[apple/xnu.git] / bsd / nfs / nfs_socket.c

/*
 * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1989, 1991, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)nfs_socket.c        8.5 (Berkeley) 3/30/95
 * FreeBSD-Id: nfs_socket.c,v 1.30 1997/10/28 15:59:07 bde Exp $
 */

/*
 * Socket operations for use by nfs
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/kauth.h>
#include <sys/mount_internal.h>
#include <sys/kernel.h>
#include <sys/kpi_mbuf.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/syslog.h>
#include <sys/tprintf.h>
#include <libkern/OSAtomic.h>

#include <sys/time.h>
#include <kern/clock.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/thread_call.h>
#include <sys/user.h>
#include <sys/acct.h>

#include <netinet/in.h>
#include <netinet/tcp.h>

#include <nfs/rpcv2.h>
#include <nfs/krpc.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/xdr_subs.h>
#include <nfs/nfsm_subs.h>
#include <nfs/nfs_gss.h>
#include <nfs/nfsmount.h>
#include <nfs/nfsnode.h>

#define NFS_SOCK_DBG(...) NFS_DBG(NFS_FAC_SOCK, 7, ## __VA_ARGS__)
#define NFS_SOCK_DUMP_MBUF(msg, mb) if (NFS_IS_DBG(NFS_FAC_SOCK, 15)) nfs_dump_mbuf(__func__, __LINE__, (msg), (mb))

/* XXX */
boolean_t       current_thread_aborted(void);
kern_return_t   thread_terminate(thread_t);


#if NFSSERVER
int nfsrv_sock_max_rec_queue_length = 128; /* max # RPC records queued on (UDP) socket */

int nfsrv_getstream(struct nfsrv_sock *, int);
int nfsrv_getreq(struct nfsrv_descript *);
extern int nfsv3_procid[NFS_NPROCS];
#endif /* NFSSERVER */

/*
 * compare two sockaddr structures
 */
int
nfs_sockaddr_cmp(struct sockaddr *sa1, struct sockaddr *sa2)
{
        if (!sa1) {
                return -1;
        }
        if (!sa2) {
                return 1;
        }
        if (sa1->sa_family != sa2->sa_family) {
                return (sa1->sa_family < sa2->sa_family) ? -1 : 1;
        }
        if (sa1->sa_len != sa2->sa_len) {
                return (sa1->sa_len < sa2->sa_len) ? -1 : 1;
        }
        if (sa1->sa_family == AF_INET) {
                return bcmp(&((struct sockaddr_in*)sa1)->sin_addr,
                           &((struct sockaddr_in*)sa2)->sin_addr, sizeof(((struct sockaddr_in*)sa1)->sin_addr));
        }
        if (sa1->sa_family == AF_INET6) {
                return bcmp(&((struct sockaddr_in6*)sa1)->sin6_addr,
                           &((struct sockaddr_in6*)sa2)->sin6_addr, sizeof(((struct sockaddr_in6*)sa1)->sin6_addr));
        }
        return -1;
}

#if NFSCLIENT

int     nfs_connect_search_new_socket(struct nfsmount *, struct nfs_socket_search *, struct timeval *);
int     nfs_connect_search_socket_connect(struct nfsmount *, struct nfs_socket *, int);
int     nfs_connect_search_ping(struct nfsmount *, struct nfs_socket *, struct timeval *);
void    nfs_connect_search_socket_found(struct nfsmount *, struct nfs_socket_search *, struct nfs_socket *);
void    nfs_connect_search_socket_reap(struct nfsmount *, struct nfs_socket_search *, struct timeval *);
int     nfs_connect_search_check(struct nfsmount *, struct nfs_socket_search *, struct timeval *);
int     nfs_reconnect(struct nfsmount *);
int     nfs_connect_setup(struct nfsmount *);
void    nfs_mount_sock_thread(void *, wait_result_t);
void    nfs_udp_rcv(socket_t, void*, int);
void    nfs_tcp_rcv(socket_t, void*, int);
void    nfs_sock_poke(struct nfsmount *);
void    nfs_request_match_reply(struct nfsmount *, mbuf_t);
void    nfs_reqdequeue(struct nfsreq *);
void    nfs_reqbusy(struct nfsreq *);
struct nfsreq *nfs_reqnext(struct nfsreq *);
int     nfs_wait_reply(struct nfsreq *);
void    nfs_softterm(struct nfsreq *);
int     nfs_can_squish(struct nfsmount *);
int     nfs_is_squishy(struct nfsmount *);
int     nfs_is_dead(int, struct nfsmount *);

/*
 * Estimate rto for an nfs rpc sent via. an unreliable datagram.
 * Use the mean and mean deviation of rtt for the appropriate type of rpc
 * for the frequent rpcs and a default for the others.
 * The justification for doing "other" this way is that these rpcs
 * happen so infrequently that timer est. would probably be stale.
 * Also, since many of these rpcs are
 * non-idempotent, a conservative timeout is desired.
 * getattr, lookup - A+2D
 * read, write     - A+4D
 * other           - nm_timeo
 */
#define NFS_RTO(n, t) \
        ((t) == 0 ? (n)->nm_timeo : \
         ((t) < 3 ? \
          (((((n)->nm_srtt[t-1] + 3) >> 2) + (n)->nm_sdrtt[t-1] + 1) >> 1) : \
          ((((n)->nm_srtt[t-1] + 7) >> 3) + (n)->nm_sdrtt[t-1] + 1)))
#define NFS_SRTT(r)     (r)->r_nmp->nm_srtt[proct[(r)->r_procnum] - 1]
#define NFS_SDRTT(r)    (r)->r_nmp->nm_sdrtt[proct[(r)->r_procnum] - 1]

/*
 * Defines which timer to use for the procnum.
 * 0 - default
 * 1 - getattr
 * 2 - lookup
 * 3 - read
 * 4 - write
 */
static const int proct[] = {
        [NFSPROC_NULL]                  =       0,
        [NFSPROC_GETATTR]               =       1,
        [NFSPROC_SETATTR]               =       0,
        [NFSPROC_LOOKUP]                =       2,
        [NFSPROC_ACCESS]                =       1,
        [NFSPROC_READLINK]              =       3,
        [NFSPROC_READ]                  =       3,
        [NFSPROC_WRITE]                 =       4,
        [NFSPROC_CREATE]                =       0,
        [NFSPROC_MKDIR]                 =       0,
        [NFSPROC_SYMLINK]               =       0,
        [NFSPROC_MKNOD]                 =       0,
        [NFSPROC_REMOVE]                =       0,
        [NFSPROC_RMDIR]                 =       0,
        [NFSPROC_RENAME]                =       0,
        [NFSPROC_LINK]                  =       0,
        [NFSPROC_READDIR]               =       3,
        [NFSPROC_READDIRPLUS]           =       3,
        [NFSPROC_FSSTAT]                =       0,
        [NFSPROC_FSINFO]                =       0,
        [NFSPROC_PATHCONF]              =       0,
        [NFSPROC_COMMIT]                =       0,
        [NFSPROC_NOOP]                  =       0,
};

/*
 * There is a congestion window for outstanding rpcs maintained per mount
 * point. The cwnd size is adjusted in roughly the way that:
 * Van Jacobson, Congestion avoidance and Control, In "Proceedings of
 * SIGCOMM '88". ACM, August 1988.
 * describes for TCP. The cwnd size is chopped in half on a retransmit timeout
 * and incremented by 1/cwnd when each rpc reply is received and a full cwnd
 * of rpcs is in progress.
 * (The sent count and cwnd are scaled for integer arith.)
 * Variants of "slow start" were tried and were found to be too much of a
 * performance hit (ave. rtt 3 times larger),
 * I suspect due to the large rtt that nfs rpcs have.
 */
#define NFS_CWNDSCALE   256
#define NFS_MAXCWND     (NFS_CWNDSCALE * 32)
static int nfs_backoff[8] = { 2, 4, 8, 16, 32, 64, 128, 256, };

/*
 * Increment location index to next address/server/location.
 */
void
nfs_location_next(struct nfs_fs_locations *nlp, struct nfs_location_index *nlip)
{
        uint8_t loc = nlip->nli_loc;
        uint8_t serv = nlip->nli_serv;
        uint8_t addr = nlip->nli_addr;

        /* move to next address */
        addr++;
        if (addr >= nlp->nl_locations[loc]->nl_servers[serv]->ns_addrcount) {
                /* no more addresses on current server, go to first address of next server */
next_server:
                addr = 0;
                serv++;
                if (serv >= nlp->nl_locations[loc]->nl_servcount) {
                        /* no more servers on current location, go to first server of next location */
                        serv = 0;
                        loc++;
                        if (loc >= nlp->nl_numlocs) {
                                loc = 0; /* after last location, wrap back around to first location */
                        }
                }
        }
        /*
         * It's possible for this next server to not have any addresses.
         * Check for that here and go to the next server.
         * But bail out if we've managed to come back around to the original
         * location that was passed in. (That would mean no servers had any
         * addresses.  And we don't want to spin here forever.)
         */
        if ((loc == nlip->nli_loc) && (serv == nlip->nli_serv) && (addr == nlip->nli_addr)) {
                return;
        }
        if (addr >= nlp->nl_locations[loc]->nl_servers[serv]->ns_addrcount) {
                goto next_server;
        }

        nlip->nli_loc = loc;
        nlip->nli_serv = serv;
        nlip->nli_addr = addr;
}

/*
 * Compare two location indices.
 */
int
nfs_location_index_cmp(struct nfs_location_index *nlip1, struct nfs_location_index *nlip2)
{
        if (nlip1->nli_loc != nlip2->nli_loc) {
                return nlip1->nli_loc - nlip2->nli_loc;
        }
        if (nlip1->nli_serv != nlip2->nli_serv) {
                return nlip1->nli_serv - nlip2->nli_serv;
        }
        return nlip1->nli_addr - nlip2->nli_addr;
}

/*
 * Get the mntfromname (or path portion only) for a given location.
 */
void
nfs_location_mntfromname(struct nfs_fs_locations *locs, struct nfs_location_index idx, char *s, int size, int pathonly)
{
        struct nfs_fs_location *fsl = locs->nl_locations[idx.nli_loc];
        char *p;
        int cnt, i;

        p = s;
        if (!pathonly) {
                char *name = fsl->nl_servers[idx.nli_serv]->ns_name;
                if (name == NULL) {
                        name = "";
                }
                if (*name == '\0') {
                        if (*fsl->nl_servers[idx.nli_serv]->ns_addresses[idx.nli_addr]) {
                                name = fsl->nl_servers[idx.nli_serv]->ns_addresses[idx.nli_addr];
                        }
                        cnt = snprintf(p, size, "<%s>:", name);
                } else {
                        cnt = snprintf(p, size, "%s:", name);
                }
                p += cnt;
                size -= cnt;
        }
        if (fsl->nl_path.np_compcount == 0) {
                /* mounting root export on server */
                if (size > 0) {
                        *p++ = '/';
                        *p++ = '\0';
                }
                return;
        }
        /* append each server path component */
        for (i = 0; (size > 0) && (i < (int)fsl->nl_path.np_compcount); i++) {
                cnt = snprintf(p, size, "/%s", fsl->nl_path.np_components[i]);
                p += cnt;
                size -= cnt;
        }
}

/*
 * NFS client connect socket upcall.
 * (Used only during socket connect/search.)
 */
void
nfs_connect_upcall(socket_t so, void *arg, __unused int waitflag)
{
        struct nfs_socket *nso = arg;
        size_t rcvlen;
        mbuf_t m;
        int error = 0, recv = 1;

        if (nso->nso_flags & NSO_CONNECTING) {
                NFS_SOCK_DBG("nfs connect - socket %p upcall - connecting flags = %8.8x\n", nso, nso->nso_flags);
                wakeup(nso->nso_wake);
                return;
        }

        lck_mtx_lock(&nso->nso_lock);
        if ((nso->nso_flags & (NSO_UPCALL | NSO_DISCONNECTING | NSO_DEAD)) || !(nso->nso_flags & NSO_PINGING)) {
                NFS_SOCK_DBG("nfs connect - socket %p upcall - nevermind\n", nso);
                lck_mtx_unlock(&nso->nso_lock);
                return;
        }
        NFS_SOCK_DBG("nfs connect - socket %p upcall %8.8x\n", nso, nso->nso_flags);
        nso->nso_flags |= NSO_UPCALL;

        /* loop while we make error-free progress */
        while (!error && recv) {
                /* make sure we're still interested in this socket */
                if (nso->nso_flags & (NSO_DISCONNECTING | NSO_DEAD)) {
                        break;
                }
                lck_mtx_unlock(&nso->nso_lock);
                m = NULL;
                if (nso->nso_sotype == SOCK_STREAM) {
                        error = nfs_rpc_record_read(so, &nso->nso_rrs, MSG_DONTWAIT, &recv, &m);
                        NFS_SOCK_DBG("nfs_rpc_record_read returned %d recv = %d\n", error, recv);
                } else {
                        rcvlen = 1000000;
                        error = sock_receivembuf(so, NULL, &m, MSG_DONTWAIT, &rcvlen);
                        recv = m ? 1 : 0;
                }
                lck_mtx_lock(&nso->nso_lock);
                if (m) {
                        /* match response with request */
                        struct nfsm_chain nmrep;
                        uint32_t reply = 0, rxid = 0, verf_type, verf_len;
                        uint32_t reply_status, rejected_status, accepted_status;

                        NFS_SOCK_DUMP_MBUF("Got mbuf from ping", m);
                        nfsm_chain_dissect_init(error, &nmrep, m);
                        nfsm_chain_get_32(error, &nmrep, rxid);
                        nfsm_chain_get_32(error, &nmrep, reply);
                        if (!error && ((reply != RPC_REPLY) || (rxid != nso->nso_pingxid))) {
                                error = EBADRPC;
                        }
                        nfsm_chain_get_32(error, &nmrep, reply_status);
                        if (!error && (reply_status == RPC_MSGDENIED)) {
                                nfsm_chain_get_32(error, &nmrep, rejected_status);
                                if (!error) {
                                        error = (rejected_status == RPC_MISMATCH) ? ERPCMISMATCH : EACCES;
                                }
                        }
                        nfsm_chain_get_32(error, &nmrep, verf_type); /* verifier flavor */
                        nfsm_chain_get_32(error, &nmrep, verf_len); /* verifier length */
                        nfsmout_if(error);
                        if (verf_len) {
                                nfsm_chain_adv(error, &nmrep, nfsm_rndup(verf_len));
                        }
                        nfsm_chain_get_32(error, &nmrep, accepted_status);
                        nfsmout_if(error);
                        NFS_SOCK_DBG("Recevied accepted_status of %d  nso_version = %d\n", accepted_status, nso->nso_version);
                        if ((accepted_status == RPC_PROGMISMATCH) && !nso->nso_version) {
                                uint32_t minvers, maxvers;
                                nfsm_chain_get_32(error, &nmrep, minvers);
                                nfsm_chain_get_32(error, &nmrep, maxvers);
                                nfsmout_if(error);
                                if (nso->nso_protocol == PMAPPROG) {
                                        if ((minvers > RPCBVERS4) || (maxvers < PMAPVERS)) {
                                                error = EPROGMISMATCH;
                                        } else if ((nso->nso_saddr->sa_family == AF_INET) &&
                                            (PMAPVERS >= minvers) && (PMAPVERS <= maxvers)) {
                                                nso->nso_version = PMAPVERS;
                                        } else if (nso->nso_saddr->sa_family == AF_INET6) {
                                                if ((RPCBVERS4 >= minvers) && (RPCBVERS4 <= maxvers)) {
                                                        nso->nso_version = RPCBVERS4;
                                                } else if ((RPCBVERS3 >= minvers) && (RPCBVERS3 <= maxvers)) {
                                                        nso->nso_version = RPCBVERS3;
                                                }
                                        }
                                } else if (nso->nso_protocol == NFS_PROG) {
                                        int vers;

                                        /*
                                         * N.B. Both portmapper and rpcbind V3 are happy to return
                                         * addresses for other versions than the one you ask (getport or
                                         * getaddr) and thus we may have fallen to this code path. So if
                                         * we get a version that we support, use highest supported
                                         * version.  This assumes that the server supports all versions
                                         * between minvers and maxvers.  Note for IPv6 we will try and
                                         * use rpcbind V4 which has getversaddr and we should not get
                                         * here if that was successful.
                                         */
                                        for (vers = nso->nso_nfs_max_vers; vers >= (int)nso->nso_nfs_min_vers; vers--) {
                                                if (vers >= (int)minvers && vers <= (int)maxvers) {
                                                        break;
                                                }
                                        }
                                        nso->nso_version = (vers < (int)nso->nso_nfs_min_vers) ? 0 : vers;
                                }
                                if (!error && nso->nso_version) {
                                        accepted_status = RPC_SUCCESS;
                                }
                        }
                        if (!error) {
                                switch (accepted_status) {
                                case RPC_SUCCESS:
                                        error = 0;
                                        break;
                                case RPC_PROGUNAVAIL:
                                        error = EPROGUNAVAIL;
                                        break;
                                case RPC_PROGMISMATCH:
                                        error = EPROGMISMATCH;
                                        break;
                                case RPC_PROCUNAVAIL:
                                        error = EPROCUNAVAIL;
                                        break;
                                case RPC_GARBAGE:
                                        error = EBADRPC;
                                        break;
                                case RPC_SYSTEM_ERR:
                                default:
                                        error = EIO;
                                        break;
                                }
                        }
nfsmout:
                        nso->nso_flags &= ~NSO_PINGING;
                        if (error) {
                                NFS_SOCK_DBG("nfs upcalled failed for %d program %d vers error = %d\n",
                                    nso->nso_protocol, nso->nso_version, error);
                                nso->nso_error = error;
                                nso->nso_flags |= NSO_DEAD;
                        } else {
                                nso->nso_flags |= NSO_VERIFIED;
                        }
                        mbuf_freem(m);
                        /* wake up search thread */
                        wakeup(nso->nso_wake);
                        break;
                }
        }

        nso->nso_flags &= ~NSO_UPCALL;
        if ((error != EWOULDBLOCK) && (error || !recv)) {
                /* problems with the socket... */
                NFS_SOCK_DBG("connect upcall failed %d\n", error);
                nso->nso_error = error ? error : EPIPE;
                nso->nso_flags |= NSO_DEAD;
                wakeup(nso->nso_wake);
        }
        if (nso->nso_flags & NSO_DISCONNECTING) {
                wakeup(&nso->nso_flags);
        }
        lck_mtx_unlock(&nso->nso_lock);
}

/*
 * Create/initialize an nfs_socket structure.
 */
int
nfs_socket_create(
        struct nfsmount *nmp,
        struct sockaddr *sa,
        int sotype,
        in_port_t port,
        uint32_t protocol,
        uint32_t vers,
        int resvport,
        struct nfs_socket **nsop)
{
        struct nfs_socket *nso;
        struct timeval now;
        int error;
#define NFS_SOCKET_DEBUGGING
#ifdef NFS_SOCKET_DEBUGGING
        char naddr[sizeof((struct sockaddr_un *)0)->sun_path];
        void *sinaddr;

        switch (sa->sa_family) {
        case AF_INET:
        case AF_INET6:
                if (sa->sa_family == AF_INET) {
                        sinaddr = &((struct sockaddr_in*)sa)->sin_addr;
                } else {
                        sinaddr = &((struct sockaddr_in6*)sa)->sin6_addr;
                }
                if (inet_ntop(sa->sa_family, sinaddr, naddr, sizeof(naddr)) != naddr) {
                        strlcpy(naddr, "<unknown>", sizeof(naddr));
                }
                break;
        case AF_LOCAL:
                strlcpy(naddr, ((struct sockaddr_un *)sa)->sun_path, sizeof(naddr));
                break;
        default:
                strlcpy(naddr, "<unsupported address family>", sizeof(naddr));
                break;
        }
#else
        char naddr[1] =  { 0 };
#endif

        *nsop = NULL;

        /* Create the socket. */
        MALLOC(nso, struct nfs_socket *, sizeof(struct nfs_socket), M_TEMP, M_WAITOK | M_ZERO);
        if (nso) {
                MALLOC(nso->nso_saddr, struct sockaddr *, sa->sa_len, M_SONAME, M_WAITOK | M_ZERO);
        }
        if (!nso || !nso->nso_saddr) {
                if (nso) {
                        FREE(nso, M_TEMP);
                }
                return ENOMEM;
        }
        lck_mtx_init(&nso->nso_lock, nfs_request_grp, LCK_ATTR_NULL);
        nso->nso_sotype = sotype;
        if (nso->nso_sotype == SOCK_STREAM) {
                nfs_rpc_record_state_init(&nso->nso_rrs);
        }
        microuptime(&now);
        nso->nso_timestamp = now.tv_sec;
        bcopy(sa, nso->nso_saddr, sa->sa_len);
        switch (sa->sa_family) {
        case AF_INET:
        case AF_INET6:
                if (sa->sa_family == AF_INET) {
                        ((struct sockaddr_in*)nso->nso_saddr)->sin_port = htons(port);
                } else if (sa->sa_family == AF_INET6) {
                        ((struct sockaddr_in6*)nso->nso_saddr)->sin6_port = htons(port);
                }
                break;
        case AF_LOCAL:
                break;
        }
        nso->nso_protocol = protocol;
        nso->nso_version = vers;
        nso->nso_nfs_min_vers = PVER2MAJOR(nmp->nm_min_vers);
        nso->nso_nfs_max_vers = PVER2MAJOR(nmp->nm_max_vers);

        error = sock_socket(sa->sa_family, nso->nso_sotype, 0, NULL, NULL, &nso->nso_so);

        /* Some servers require that the client port be a reserved port number. */
        if (!error && resvport && ((sa->sa_family == AF_INET) || (sa->sa_family == AF_INET6))) {
                struct sockaddr_storage ss;
                int level = (sa->sa_family == AF_INET) ? IPPROTO_IP : IPPROTO_IPV6;
                int optname = (sa->sa_family == AF_INET) ? IP_PORTRANGE : IPV6_PORTRANGE;
                int portrange = IP_PORTRANGE_LOW;

                error = sock_setsockopt(nso->nso_so, level, optname, &portrange, sizeof(portrange));
                if (!error) {   /* bind now to check for failure */
                        ss.ss_len = sa->sa_len;
                        ss.ss_family = sa->sa_family;
                        if (ss.ss_family == AF_INET) {
                                ((struct sockaddr_in*)&ss)->sin_addr.s_addr = INADDR_ANY;
                                ((struct sockaddr_in*)&ss)->sin_port = htons(0);
                        } else if (ss.ss_family == AF_INET6) {
                                ((struct sockaddr_in6*)&ss)->sin6_addr = in6addr_any;
                                ((struct sockaddr_in6*)&ss)->sin6_port = htons(0);
                        } else {
                                error = EINVAL;
                        }
                        if (!error) {
                                error = sock_bind(nso->nso_so, (struct sockaddr*)&ss);
                        }
                }
        }

        if (error) {
                NFS_SOCK_DBG("nfs connect %s error %d creating socket %p %s type %d%s port %d prot %d %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, error, nso, naddr, sotype,
                    resvport ? "r" : "", port, protocol, vers);
                nfs_socket_destroy(nso);
        } else {
                NFS_SOCK_DBG("nfs connect %s created socket %p <%s> type %d%s port %d prot %d %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, naddr,
                    sotype, resvport ? "r" : "", port, protocol, vers);
                *nsop = nso;
        }
        return error;
}

/*
 * Destroy an nfs_socket structure.
 */
void
nfs_socket_destroy(struct nfs_socket *nso)
{
        struct timespec ts = { .tv_sec = 4, .tv_nsec = 0 };

        NFS_SOCK_DBG("Destoring socket %p flags = %8.8x error = %d\n", nso, nso->nso_flags, nso->nso_error);
        lck_mtx_lock(&nso->nso_lock);
        nso->nso_flags |= NSO_DISCONNECTING;
        if (nso->nso_flags & NSO_UPCALL) { /* give upcall a chance to complete */
                msleep(&nso->nso_flags, &nso->nso_lock, PZERO - 1, "nfswaitupcall", &ts);
        }
        lck_mtx_unlock(&nso->nso_lock);
        sock_shutdown(nso->nso_so, SHUT_RDWR);
        sock_close(nso->nso_so);
        if (nso->nso_sotype == SOCK_STREAM) {
                nfs_rpc_record_state_cleanup(&nso->nso_rrs);
        }
        lck_mtx_destroy(&nso->nso_lock, nfs_request_grp);
        if (nso->nso_saddr) {
                FREE(nso->nso_saddr, M_SONAME);
        }
        if (nso->nso_saddr2) {
                FREE(nso->nso_saddr2, M_SONAME);
        }
        NFS_SOCK_DBG("nfs connect - socket %p destroyed\n", nso);
        FREE(nso, M_TEMP);
}

/*
 * Set common socket options on an nfs_socket.
 */
void
nfs_socket_options(struct nfsmount *nmp, struct nfs_socket *nso)
{
        /*
         * Set socket send/receive timeouts
         * - Receive timeout shouldn't matter because most receives are performed
         *   in the socket upcall non-blocking.
         * - Send timeout should allow us to react to a blocked socket.
         *   Soft mounts will want to abort sooner.
         */
        struct timeval timeo;
        int on = 1, proto;

        timeo.tv_usec = 0;
        timeo.tv_sec = (NMFLAG(nmp, SOFT) || nfs_can_squish(nmp)) ? 5 : 60;
        sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
        sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
        if (nso->nso_sotype == SOCK_STREAM) {
                /* Assume that SOCK_STREAM always requires a connection */
                sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on));
                /* set nodelay for TCP */
                sock_gettype(nso->nso_so, NULL, NULL, &proto);
                if (proto == IPPROTO_TCP) {
                        sock_setsockopt(nso->nso_so, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
                }
        }
        if (nso->nso_sotype == SOCK_DGRAM || nso->nso_saddr->sa_family == AF_LOCAL) { /* set socket buffer sizes for UDP */
                int reserve = (nso->nso_sotype == SOCK_DGRAM) ? NFS_UDPSOCKBUF : (2 * 1024 * 1024);
                sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_SNDBUF, &reserve, sizeof(reserve));
                sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_RCVBUF, &reserve, sizeof(reserve));
        }
        /* set SO_NOADDRERR to detect network changes ASAP */
        sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_NOADDRERR, &on, sizeof(on));
        /* just playin' it safe with upcalls */
        sock_setsockopt(nso->nso_so, SOL_SOCKET, SO_UPCALLCLOSEWAIT, &on, sizeof(on));
        /* socket should be interruptible if the mount is */
        if (!NMFLAG(nmp, INTR)) {
                sock_nointerrupt(nso->nso_so, 1);
        }
}

/*
 * Release resources held in an nfs_socket_search.
 */
void
nfs_socket_search_cleanup(struct nfs_socket_search *nss)
{
        struct nfs_socket *nso, *nsonext;

        TAILQ_FOREACH_SAFE(nso, &nss->nss_socklist, nso_link, nsonext) {
                TAILQ_REMOVE(&nss->nss_socklist, nso, nso_link);
                nss->nss_sockcnt--;
                nfs_socket_destroy(nso);
        }
        if (nss->nss_sock) {
                nfs_socket_destroy(nss->nss_sock);
                nss->nss_sock = NULL;
        }
}

/*
 * Prefer returning certain errors over others.
 * This function returns a ranking of the given error.
 */
int
nfs_connect_error_class(int error)
{
        switch (error) {
        case 0:
                return 0;
        case ETIMEDOUT:
        case EAGAIN:
                return 1;
        case EPIPE:
        case EADDRNOTAVAIL:
        case ENETDOWN:
        case ENETUNREACH:
        case ENETRESET:
        case ECONNABORTED:
        case ECONNRESET:
        case EISCONN:
        case ENOTCONN:
        case ESHUTDOWN:
        case ECONNREFUSED:
        case EHOSTDOWN:
        case EHOSTUNREACH:
                return 2;
        case ERPCMISMATCH:
        case EPROCUNAVAIL:
        case EPROGMISMATCH:
        case EPROGUNAVAIL:
                return 3;
        case EBADRPC:
                return 4;
        default:
                return 5;
        }
}

/*
 * Make sure a socket search returns the best error.
 */
void
nfs_socket_search_update_error(struct nfs_socket_search *nss, int error)
{
        if (nfs_connect_error_class(error) >= nfs_connect_error_class(nss->nss_error)) {
                nss->nss_error = error;
        }
}

/* nfs_connect_search_new_socket:
 *      Given a socket search structure for an nfs mount try to find a new socket from the set of addresses specified
 *      by nss.
 *
 *      nss_last is set to -1 at initialization to indicate the first time. Its set to -2 if address was found but
 *      could not be used or if a socket timed out.
 */
int
nfs_connect_search_new_socket(struct nfsmount *nmp, struct nfs_socket_search *nss, struct timeval *now)
{
        struct nfs_fs_location *fsl;
        struct nfs_fs_server *fss;
        struct sockaddr_storage ss;
        struct nfs_socket *nso;
        char *addrstr;
        int error = 0;


        NFS_SOCK_DBG("nfs connect %s nss_addrcnt = %d\n",
            vfs_statfs(nmp->nm_mountp)->f_mntfromname, nss->nss_addrcnt);

        /*
         * while there are addresses and:
         *      we have no sockets or
         *      the last address failed and did not produce a socket (nss_last < 0) or
         *      Its been a while (2 seconds) and we have less than the max number of concurrent sockets to search (4)
         *      then attempt to create a socket with the current address.
         */
        while (nss->nss_addrcnt > 0 && ((nss->nss_last < 0) || (nss->nss_sockcnt == 0) ||
            ((nss->nss_sockcnt < 4) && (now->tv_sec >= (nss->nss_last + 2))))) {
                if (nmp->nm_sockflags & NMSOCK_UNMOUNT) {
                        return EINTR;
                }
                /* Can we convert the address to a sockaddr? */
                fsl = nmp->nm_locations.nl_locations[nss->nss_nextloc.nli_loc];
                fss = fsl->nl_servers[nss->nss_nextloc.nli_serv];
                addrstr = fss->ns_addresses[nss->nss_nextloc.nli_addr];
                NFS_SOCK_DBG("Trying address %s for program %d on port %d\n", addrstr, nss->nss_protocol, nss->nss_port);
                if (*addrstr == '\0') {
                        /*
                         * We have an unspecified local domain address. We use the program to translate to
                         * a well known local transport address. We only support PMAPROG and NFS for this.
                         */
                        if (nss->nss_protocol == PMAPPROG) {
                                addrstr = (nss->nss_sotype == SOCK_DGRAM) ? RPCB_TICLTS_PATH : RPCB_TICOTSORD_PATH;
                        } else if (nss->nss_protocol == NFS_PROG) {
                                addrstr = nmp->nm_nfs_localport;
                                if (!addrstr || *addrstr == '\0') {
                                        addrstr = (nss->nss_sotype == SOCK_DGRAM) ? NFS_TICLTS_PATH : NFS_TICOTSORD_PATH;
                                }
                        }
                        NFS_SOCK_DBG("Calling  prog %d with <%s>\n", nss->nss_protocol, addrstr);
                }
                if (!nfs_uaddr2sockaddr(addrstr, (struct sockaddr*)&ss)) {
                        NFS_SOCK_DBG("Could not convert address %s to socket\n", addrstr);
                        nfs_location_next(&nmp->nm_locations, &nss->nss_nextloc);
                        nss->nss_addrcnt -= 1;
                        nss->nss_last = -2;
                        continue;
                }
                /* Check that socket family is acceptable. */
                if (nmp->nm_sofamily && (ss.ss_family != nmp->nm_sofamily)) {
                        NFS_SOCK_DBG("Skipping socket family %d, want mount family %d\n", ss.ss_family, nmp->nm_sofamily);
                        nfs_location_next(&nmp->nm_locations, &nss->nss_nextloc);
                        nss->nss_addrcnt -= 1;
                        nss->nss_last = -2;
                        continue;
                }

                /* Create the socket. */
                error = nfs_socket_create(nmp, (struct sockaddr*)&ss, nss->nss_sotype,
                    nss->nss_port, nss->nss_protocol, nss->nss_version,
                    ((nss->nss_protocol == NFS_PROG) && NMFLAG(nmp, RESVPORT)), &nso);
                if (error) {
                        return error;
                }

                nso->nso_location = nss->nss_nextloc;
                nso->nso_wake = nss;
                error = sock_setupcall(nso->nso_so, nfs_connect_upcall, nso);
                if (error) {
                        NFS_SOCK_DBG("sock_setupcall failed for socket %p setting nfs_connect_upcall error = %d\n", nso, error);
                        lck_mtx_lock(&nso->nso_lock);
                        nso->nso_error = error;
                        nso->nso_flags |= NSO_DEAD;
                        lck_mtx_unlock(&nso->nso_lock);
                }

                TAILQ_INSERT_TAIL(&nss->nss_socklist, nso, nso_link);
                nss->nss_sockcnt++;
                nfs_location_next(&nmp->nm_locations, &nss->nss_nextloc);
                nss->nss_addrcnt -= 1;

                nss->nss_last = now->tv_sec;
        }

        if (nss->nss_addrcnt == 0 && nss->nss_last < 0) {
                nss->nss_last = now->tv_sec;
        }

        return error;
}

/*
 * nfs_connect_search_socket_connect:   Connect an nfs socket nso for nfsmount nmp.
 *                                      If successful set the socket options for the socket as require from the mount.
 *
 * Assumes:                             nso->nso_lock is held on entry and return.
 */
int
nfs_connect_search_socket_connect(struct nfsmount *nmp, struct nfs_socket *nso, int verbose)
{
        int error;

        if ((nso->nso_sotype != SOCK_STREAM) && NMFLAG(nmp, NOCONNECT)) {
                /* no connection needed, just say it's already connected */
                NFS_SOCK_DBG("nfs connect %s UDP socket %p noconnect\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);
                nso->nso_flags |= NSO_CONNECTED;
                nfs_socket_options(nmp, nso);
                return 1;   /* Socket is connected and setup */
        } else if (!(nso->nso_flags & NSO_CONNECTING)) {
                /* initiate the connection */
                nso->nso_flags |= NSO_CONNECTING;
                lck_mtx_unlock(&nso->nso_lock);
                NFS_SOCK_DBG("nfs connect %s connecting socket %p %s\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso,
                    nso->nso_saddr->sa_family == AF_LOCAL ? ((struct sockaddr_un*)nso->nso_saddr)->sun_path : "");
                error = sock_connect(nso->nso_so, nso->nso_saddr, MSG_DONTWAIT);
                if (error) {
                        NFS_SOCK_DBG("nfs connect %s connecting socket %p returned %d\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, error);
                }
                lck_mtx_lock(&nso->nso_lock);
                if (error && (error != EINPROGRESS)) {
                        nso->nso_error = error;
                        nso->nso_flags |= NSO_DEAD;
                        return 0;
                }
        }
        if (nso->nso_flags & NSO_CONNECTING) {
                /* check the connection */
                if (sock_isconnected(nso->nso_so)) {
                        NFS_SOCK_DBG("nfs connect %s socket %p is connected\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);
                        nso->nso_flags &= ~NSO_CONNECTING;
                        nso->nso_flags |= NSO_CONNECTED;
                        nfs_socket_options(nmp, nso);
                        return 1;   /* Socket is connected and setup */
                } else {
                        int optlen = sizeof(error);
                        error = 0;
                        sock_getsockopt(nso->nso_so, SOL_SOCKET, SO_ERROR, &error, &optlen);
                        if (error) { /* we got an error on the socket */
                                NFS_SOCK_DBG("nfs connect %s socket %p connection error %d\n",
                                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, error);
                                if (verbose) {
                                        printf("nfs connect socket error %d for %s\n",
                                            error, vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                                }
                                nso->nso_error = error;
                                nso->nso_flags |= NSO_DEAD;
                                return 0;
                        }
                }
        }

        return 0;  /* Waiting to be connected */
}

/*
 * nfs_connect_search_ping:     Send a null proc on the nso socket.
 */
int
nfs_connect_search_ping(struct nfsmount *nmp, struct nfs_socket *nso, struct timeval *now)
{
        /* initiate a NULL RPC request */
        uint64_t xid = nso->nso_pingxid;
        mbuf_t m, mreq = NULL;
        struct msghdr msg;
        size_t reqlen, sentlen;
        uint32_t vers = nso->nso_version;
        int error;

        if (!vers) {
                if (nso->nso_protocol == PMAPPROG) {
                        vers = (nso->nso_saddr->sa_family == AF_INET) ? PMAPVERS : RPCBVERS4;
                } else if (nso->nso_protocol == NFS_PROG) {
                        vers = PVER2MAJOR(nmp->nm_max_vers);
                }
        }
        lck_mtx_unlock(&nso->nso_lock);
        NFS_SOCK_DBG("Pinging  socket %p %d %d %d\n", nso, nso->nso_sotype, nso->nso_protocol, vers);
        error = nfsm_rpchead2(nmp, nso->nso_sotype, nso->nso_protocol, vers, 0, RPCAUTH_SYS,
            vfs_context_ucred(vfs_context_kernel()), NULL, NULL, &xid, &mreq);
        lck_mtx_lock(&nso->nso_lock);
        if (!error) {
                nso->nso_flags |= NSO_PINGING;
                nso->nso_pingxid = R_XID32(xid);
                nso->nso_reqtimestamp = now->tv_sec;
                bzero(&msg, sizeof(msg));
                if ((nso->nso_sotype != SOCK_STREAM) && !sock_isconnected(nso->nso_so)) {
                        msg.msg_name = nso->nso_saddr;
                        msg.msg_namelen = nso->nso_saddr->sa_len;
                }
                for (reqlen = 0, m = mreq; m; m = mbuf_next(m)) {
                        reqlen += mbuf_len(m);
                }
                lck_mtx_unlock(&nso->nso_lock);
                NFS_SOCK_DUMP_MBUF("Sending ping packet", mreq);
                error = sock_sendmbuf(nso->nso_so, &msg, mreq, 0, &sentlen);
                NFS_SOCK_DBG("nfs connect %s verifying socket %p send rv %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, error);
                lck_mtx_lock(&nso->nso_lock);
                if (!error && (sentlen != reqlen)) {
                        error = ETIMEDOUT;
                }
        }
        if (error) {
                nso->nso_error = error;
                nso->nso_flags |= NSO_DEAD;
                return 0;
        }

        return 1;
}

/*
 * nfs_connect_search_socket_found:     Take the found socket of the socket search list and assign it to the searched socket.
 *                                      Set the nfs socket protocol and version if needed.
 */
void
nfs_connect_search_socket_found(struct nfsmount *nmp, struct nfs_socket_search *nss, struct nfs_socket *nso)
{
        NFS_SOCK_DBG("nfs connect %s socket %p verified\n",
            vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);
        if (!nso->nso_version) {
                /* If the version isn't set, the default must have worked. */
                if (nso->nso_protocol == PMAPPROG) {
                        nso->nso_version = (nso->nso_saddr->sa_family == AF_INET) ? PMAPVERS : RPCBVERS4;
                }
                if (nso->nso_protocol == NFS_PROG) {
                        nso->nso_version = PVER2MAJOR(nmp->nm_max_vers);
                }
        }
        TAILQ_REMOVE(&nss->nss_socklist, nso, nso_link);
        nss->nss_sockcnt--;
        nss->nss_sock = nso;
}

/*
 * nfs_connect_search_socket_reap:      For each socket in the search list mark any timed out socket as dead and remove from
 *                                      the list. Dead socket are then destroyed.
 */
void
nfs_connect_search_socket_reap(struct nfsmount *nmp __unused, struct nfs_socket_search *nss, struct timeval *now)
{
        struct nfs_socket *nso, *nsonext;

        TAILQ_FOREACH_SAFE(nso, &nss->nss_socklist, nso_link, nsonext) {
                lck_mtx_lock(&nso->nso_lock);
                if (now->tv_sec >= (nso->nso_timestamp + nss->nss_timeo)) {
                        /* took too long */
                        NFS_SOCK_DBG("nfs connect %s socket %p timed out\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);
                        nso->nso_error = ETIMEDOUT;
                        nso->nso_flags |= NSO_DEAD;
                }
                if (!(nso->nso_flags & NSO_DEAD)) {
                        lck_mtx_unlock(&nso->nso_lock);
                        continue;
                }
                lck_mtx_unlock(&nso->nso_lock);
                NFS_SOCK_DBG("nfs connect %s reaping socket %p error = %d flags = %8.8x\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, nso->nso_error, nso->nso_flags);
                nfs_socket_search_update_error(nss, nso->nso_error);
                TAILQ_REMOVE(&nss->nss_socklist, nso, nso_link);
                nss->nss_sockcnt--;
                nfs_socket_destroy(nso);
                /* If there are more sockets to try, force the starting of another socket */
                if (nss->nss_addrcnt > 0) {
                        nss->nss_last = -2;
                }
        }
}

/*
 * nfs_connect_search_check:    Check on the status of search and wait for replies if needed.
 */
int
nfs_connect_search_check(struct nfsmount *nmp, struct nfs_socket_search *nss, struct timeval *now)
{
        int error;

        /* log a warning if connect is taking a while */
        if (((now->tv_sec - nss->nss_timestamp) >= 8) && ((nss->nss_flags & (NSS_VERBOSE | NSS_WARNED)) == NSS_VERBOSE)) {
                printf("nfs_connect: socket connect taking a while for %s\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                nss->nss_flags |= NSS_WARNED;
        }
        if (nmp->nm_sockflags & NMSOCK_UNMOUNT) {
                return EINTR;
        }
        if ((error = nfs_sigintr(nmp, NULL, current_thread(), 0))) {
                return error;
        }

        /* If we were succesfull at sending a ping, wait up to a second for a reply  */
        if (nss->nss_last >= 0) {
                tsleep(nss, PSOCK, "nfs_connect_search_wait", hz);
        }

        return 0;
}


/*
 * Continue the socket search until we have something to report.
 */
int
nfs_connect_search_loop(struct nfsmount *nmp, struct nfs_socket_search *nss)
{
        struct nfs_socket *nso;
        struct timeval now;
        int error;
        int verbose = (nss->nss_flags & NSS_VERBOSE);

loop:
        microuptime(&now);
        NFS_SOCK_DBG("nfs connect %s search %ld\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname, now.tv_sec);

        /* add a new socket to the socket list if needed and available */
        error = nfs_connect_search_new_socket(nmp, nss, &now);
        if (error) {
                NFS_SOCK_DBG("nfs connect returned %d\n", error);
                return error;
        }

        /* check each active socket on the list and try to push it along */
        TAILQ_FOREACH(nso, &nss->nss_socklist, nso_link) {
                lck_mtx_lock(&nso->nso_lock);

                /* If not connected connect it */
                if (!(nso->nso_flags & NSO_CONNECTED)) {
                        if (!nfs_connect_search_socket_connect(nmp, nso, verbose)) {
                                lck_mtx_unlock(&nso->nso_lock);
                                continue;
                        }
                }

                /* If the socket hasn't been verified or in a ping, ping it. We also handle UDP retransmits */
                if (!(nso->nso_flags & (NSO_PINGING | NSO_VERIFIED)) ||
                    ((nso->nso_sotype == SOCK_DGRAM) && (now.tv_sec >= nso->nso_reqtimestamp + 2))) {
                        if (!nfs_connect_search_ping(nmp, nso, &now)) {
                                lck_mtx_unlock(&nso->nso_lock);
                                continue;
                        }
                }

                /* Has the socket been verified by the up call routine? */
                if (nso->nso_flags & NSO_VERIFIED) {
                        /* WOOHOO!! This socket looks good! */
                        nfs_connect_search_socket_found(nmp, nss, nso);
                        lck_mtx_unlock(&nso->nso_lock);
                        break;
                }
                lck_mtx_unlock(&nso->nso_lock);
        }

        /* Check for timed out sockets and mark as dead and then remove all dead sockets. */
        nfs_connect_search_socket_reap(nmp, nss, &now);

        /*
         * Keep looping if we haven't found a socket yet and we have more
         * sockets to (continue to) try.
         */
        error = 0;
        if (!nss->nss_sock && (!TAILQ_EMPTY(&nss->nss_socklist) || nss->nss_addrcnt)) {
                error = nfs_connect_search_check(nmp, nss, &now);
                if (!error) {
                        goto loop;
                }
        }

        NFS_SOCK_DBG("nfs connect %s returning %d\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname, error);
        return error;
}

/*
 * Initialize a new NFS connection.
 *
 * Search for a location to connect a socket to and initialize the connection.
 *
 * An NFS mount may have multiple locations/servers/addresses available.
 * We attempt to connect to each one asynchronously and will start
 * several sockets in parallel if other locations are slow to answer.
 * We'll use the first NFS socket we can successfully set up.
 *
 * The search may involve contacting the portmapper service first.
 *
 * A mount's initial connection may require negotiating some parameters such
 * as socket type and NFS version.
 */

int
nfs_connect(struct nfsmount *nmp, int verbose, int timeo)
{
        struct nfs_socket_search nss;
        struct nfs_socket *nso, *nsonfs;
        struct sockaddr_storage ss;
        struct sockaddr *saddr, *oldsaddr;
        sock_upcall upcall;
#if CONFIG_NFS4
        struct timeval now;
#endif
        struct timeval start;
        int error, savederror, nfsvers;
        int tryv4 = 1;
        uint8_t sotype = nmp->nm_sotype ? nmp->nm_sotype : SOCK_STREAM;
        fhandle_t *fh = NULL;
        char *path = NULL;
        in_port_t port;
        int addrtotal = 0;

        /* paranoia... check that we have at least one address in the locations */
        uint32_t loc, serv;
        for (loc = 0; loc < nmp->nm_locations.nl_numlocs; loc++) {
                for (serv = 0; serv < nmp->nm_locations.nl_locations[loc]->nl_servcount; serv++) {
                        addrtotal += nmp->nm_locations.nl_locations[loc]->nl_servers[serv]->ns_addrcount;
                        if (nmp->nm_locations.nl_locations[loc]->nl_servers[serv]->ns_addrcount == 0) {
                                NFS_SOCK_DBG("nfs connect %s search, server %s has no addresses\n",
                                    vfs_statfs(nmp->nm_mountp)->f_mntfromname,
                                    nmp->nm_locations.nl_locations[loc]->nl_servers[serv]->ns_name);
                        }
                }
        }

        if (addrtotal == 0) {
                NFS_SOCK_DBG("nfs connect %s search failed, no addresses\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                return EINVAL;
        } else {
                NFS_SOCK_DBG("nfs connect %s has %d addresses\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, addrtotal);
        }

        lck_mtx_lock(&nmp->nm_lock);
        nmp->nm_sockflags |= NMSOCK_CONNECTING;
        nmp->nm_nss = &nss;
        lck_mtx_unlock(&nmp->nm_lock);
        microuptime(&start);
        savederror = error = 0;

tryagain:
        /* initialize socket search state */
        bzero(&nss, sizeof(nss));
        nss.nss_addrcnt = addrtotal;
        nss.nss_error = savederror;
        TAILQ_INIT(&nss.nss_socklist);
        nss.nss_sotype = sotype;
        nss.nss_startloc = nmp->nm_locations.nl_current;
        nss.nss_timestamp = start.tv_sec;
        nss.nss_timeo = timeo;
        if (verbose) {
                nss.nss_flags |= NSS_VERBOSE;
        }

        /* First time connecting, we may need to negotiate some things */
        if (!(nmp->nm_sockflags & NMSOCK_HASCONNECTED)) {
                NFS_SOCK_DBG("so_family = %d\n", nmp->nm_sofamily);
                NFS_SOCK_DBG("nfs port = %d local: <%s>\n", nmp->nm_nfsport, nmp->nm_nfs_localport ? nmp->nm_nfs_localport : "");
                NFS_SOCK_DBG("mount port = %d local: <%s>\n", nmp->nm_mountport, nmp->nm_mount_localport ? nmp->nm_mount_localport : "");
                if (!nmp->nm_vers) {
                        /* No NFS version specified... */
                        if (!nmp->nm_nfsport || (!NM_OMATTR_GIVEN(nmp, FH) && !nmp->nm_mountport)) {
#if CONFIG_NFS4
                                if (PVER2MAJOR(nmp->nm_max_vers) >= NFS_VER4 && tryv4) {
                                        nss.nss_port = NFS_PORT;
                                        nss.nss_protocol = NFS_PROG;
                                        nss.nss_version = 4;
                                        nss.nss_flags |= NSS_FALLBACK2PMAP;
                                } else {
#endif
                                /* ...connect to portmapper first if we (may) need any ports. */
                                nss.nss_port = PMAPPORT;
                                nss.nss_protocol = PMAPPROG;
                                nss.nss_version = 0;
#if CONFIG_NFS4
                        }
#endif
                        } else {
                                /* ...connect to NFS port first. */
                                nss.nss_port = nmp->nm_nfsport;
                                nss.nss_protocol = NFS_PROG;
                                nss.nss_version = 0;
                        }
#if CONFIG_NFS4
                } else if (nmp->nm_vers >= NFS_VER4) {
                        if (tryv4) {
                                /* For NFSv4, we use the given (or default) port. */
                                nss.nss_port = nmp->nm_nfsport ? nmp->nm_nfsport : NFS_PORT;
                                nss.nss_protocol = NFS_PROG;
                                nss.nss_version = 4;
                                /*
                                 * set NSS_FALLBACK2PMAP here to pick up any non standard port
                                 * if no port is specified on the mount;
                                 * Note nm_vers is set so we will only try NFS_VER4.
                                 */
                                if (!nmp->nm_nfsport) {
                                        nss.nss_flags |= NSS_FALLBACK2PMAP;
                                }
                        } else {
                                nss.nss_port = PMAPPORT;
                                nss.nss_protocol = PMAPPROG;
                                nss.nss_version = 0;
                        }
#endif
                } else {
                        /* For NFSv3/v2... */
                        if (!nmp->nm_nfsport || (!NM_OMATTR_GIVEN(nmp, FH) && !nmp->nm_mountport)) {
                                /* ...connect to portmapper first if we need any ports. */
                                nss.nss_port = PMAPPORT;
                                nss.nss_protocol = PMAPPROG;
                                nss.nss_version = 0;
                        } else {
                                /* ...connect to NFS port first. */
                                nss.nss_port = nmp->nm_nfsport;
                                nss.nss_protocol = NFS_PROG;
                                nss.nss_version = nmp->nm_vers;
                        }
                }
                NFS_SOCK_DBG("nfs connect first %s, so type %d port %d prot %d %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nss.nss_sotype, nss.nss_port,
                    nss.nss_protocol, nss.nss_version);
        } else {
                /* we've connected before, just connect to NFS port */
                if (!nmp->nm_nfsport) {
                        /* need to ask portmapper which port that would be */
                        nss.nss_port = PMAPPORT;
                        nss.nss_protocol = PMAPPROG;
                        nss.nss_version = 0;
                } else {
                        nss.nss_port = nmp->nm_nfsport;
                        nss.nss_protocol = NFS_PROG;
                        nss.nss_version = nmp->nm_vers;
                }
                NFS_SOCK_DBG("nfs connect %s, so type %d port %d prot %d %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nss.nss_sotype, nss.nss_port,
                    nss.nss_protocol, nss.nss_version);
        }

        /* Set next location to first valid location. */
        /* If start location is invalid, find next location. */
        nss.nss_nextloc = nss.nss_startloc;
        if ((nss.nss_nextloc.nli_serv >= nmp->nm_locations.nl_locations[nss.nss_nextloc.nli_loc]->nl_servcount) ||
            (nss.nss_nextloc.nli_addr >= nmp->nm_locations.nl_locations[nss.nss_nextloc.nli_loc]->nl_servers[nss.nss_nextloc.nli_serv]->ns_addrcount)) {
                nfs_location_next(&nmp->nm_locations, &nss.nss_nextloc);
                if (!nfs_location_index_cmp(&nss.nss_nextloc, &nss.nss_startloc)) {
                        NFS_SOCK_DBG("nfs connect %s search failed, couldn't find a valid location index\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                        return ENOENT;
                }
        }
        nss.nss_last = -1;

keepsearching:

        error = nfs_connect_search_loop(nmp, &nss);
        if (error || !nss.nss_sock) {
                /* search failed */
                nfs_socket_search_cleanup(&nss);
                if (nss.nss_flags & NSS_FALLBACK2PMAP) {
                        tryv4 = 0;
                        NFS_SOCK_DBG("nfs connect %s TCP failed for V4 %d %d, trying PORTMAP\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname, error, nss.nss_error);
                        goto tryagain;
                }

                if (!error && (nss.nss_sotype == SOCK_STREAM) && !nmp->nm_sotype && (nmp->nm_vers < NFS_VER4)) {
                        /* Try using UDP */
                        sotype = SOCK_DGRAM;
                        savederror = nss.nss_error;
                        NFS_SOCK_DBG("nfs connect %s TCP failed %d %d, trying UDP\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname, error, nss.nss_error);
                        goto tryagain;
                }
                if (!error) {
                        error = nss.nss_error ? nss.nss_error : ETIMEDOUT;
                }
                lck_mtx_lock(&nmp->nm_lock);
                nmp->nm_sockflags &= ~NMSOCK_CONNECTING;
                nmp->nm_nss = NULL;
                lck_mtx_unlock(&nmp->nm_lock);
                if (nss.nss_flags & NSS_WARNED) {
                        log(LOG_INFO, "nfs_connect: socket connect aborted for %s\n",
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                }
                if (fh) {
                        FREE(fh, M_TEMP);
                }
                if (path) {
                        FREE_ZONE(path, MAXPATHLEN, M_NAMEI);
                }
                NFS_SOCK_DBG("nfs connect %s search failed, returning %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, error);
                return error;
        }

        /* try to use nss_sock */
        nso = nss.nss_sock;
        nss.nss_sock = NULL;

        /* We may be speaking to portmap first... to determine port(s). */
        if (nso->nso_saddr->sa_family == AF_INET) {
                port = ntohs(((struct sockaddr_in*)nso->nso_saddr)->sin_port);
        } else if (nso->nso_saddr->sa_family == AF_INET6) {
                port = ntohs(((struct sockaddr_in6*)nso->nso_saddr)->sin6_port);
        } else if (nso->nso_saddr->sa_family == AF_LOCAL) {
                if (nso->nso_protocol == PMAPPROG) {
                        port = PMAPPORT;
                }
        }

        if (port == PMAPPORT) {
                /* Use this portmapper port to get the port #s we need. */
                NFS_SOCK_DBG("nfs connect %s got portmapper socket %p\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);

                /* remove the connect upcall so nfs_portmap_lookup() can use this socket */
                sock_setupcall(nso->nso_so, NULL, NULL);

                /* Set up socket address and port for NFS socket. */
                bcopy(nso->nso_saddr, &ss, nso->nso_saddr->sa_len);

                /* If NFS version not set, try nm_max_vers down to nm_min_vers */
                nfsvers = nmp->nm_vers ? nmp->nm_vers : PVER2MAJOR(nmp->nm_max_vers);
                if (!(port = nmp->nm_nfsport)) {
                        if (ss.ss_family == AF_INET) {
                                ((struct sockaddr_in*)&ss)->sin_port = htons(0);
                        } else if (ss.ss_family == AF_INET6) {
                                ((struct sockaddr_in6*)&ss)->sin6_port = htons(0);
                        } else if (ss.ss_family == AF_LOCAL) {
                                if (((struct sockaddr_un*)&ss)->sun_path[0] == '/') {
                                        NFS_SOCK_DBG("Looking up  NFS socket over %s\n", ((struct sockaddr_un*)&ss)->sun_path);
                                }
                        }
                        for (; nfsvers >= (int)PVER2MAJOR(nmp->nm_min_vers); nfsvers--) {
                                if (nmp->nm_vers && nmp->nm_vers != nfsvers) {
                                        continue; /* Wrong version */
                                }
#if CONFIG_NFS4
                                if (nfsvers == NFS_VER4 && nso->nso_sotype == SOCK_DGRAM) {
                                        continue; /* NFSv4 does not do UDP */
                                }
#endif
                                if (ss.ss_family == AF_LOCAL && nmp->nm_nfs_localport) {
                                        struct sockaddr_un *sun = (struct sockaddr_un *)&ss;
                                        NFS_SOCK_DBG("Using supplied local address %s for NFS_PROG\n", nmp->nm_nfs_localport);
                                        strlcpy(sun->sun_path, nmp->nm_nfs_localport, sizeof(sun->sun_path));
                                        error = 0;
                                } else {
                                        NFS_SOCK_DBG("Calling Portmap/Rpcbind for NFS_PROG");
                                        error = nfs_portmap_lookup(nmp, vfs_context_current(), (struct sockaddr*)&ss,
                                            nso->nso_so, NFS_PROG, nfsvers, nso->nso_sotype, timeo);
                                }
                                if (!error) {
                                        if (ss.ss_family == AF_INET) {
                                                port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
                                        } else if (ss.ss_family == AF_INET6) {
                                                port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
                                        } else if (ss.ss_family == AF_LOCAL) {
                                                port = ((struct sockaddr_un *)&ss)->sun_path[0] ? NFS_PORT : 0;
                                        }
                                        if (!port) {
                                                error = EPROGUNAVAIL;
                                        }
#if CONFIG_NFS4
                                        if (port == NFS_PORT && nfsvers == NFS_VER4 && tryv4 == 0) {
                                                continue; /* We already tried this */
                                        }
#endif
                                }
                                if (!error) {
                                        break;
                                }
                        }
                        if (nfsvers < (int)PVER2MAJOR(nmp->nm_min_vers) && error == 0) {
                                error = EPROGUNAVAIL;
                        }
                        if (error) {
                                nfs_socket_search_update_error(&nss, error);
                                nfs_socket_destroy(nso);
                                NFS_SOCK_DBG("Could not lookup NFS socket address for version %d error = %d\n", nfsvers, error);
                                goto keepsearching;
                        }
                } else if (nmp->nm_nfs_localport) {
                        strlcpy(((struct sockaddr_un*)&ss)->sun_path, nmp->nm_nfs_localport, sizeof(((struct sockaddr_un*)&ss)->sun_path));
                        NFS_SOCK_DBG("Using supplied nfs_local_port %s for NFS_PROG\n", nmp->nm_nfs_localport);
                }

                /* Create NFS protocol socket and add it to the list of sockets. */
                /* N.B. If nfsvers is NFS_VER4 at this point then we're on a non standard port */
                if (ss.ss_family == AF_LOCAL) {
                        NFS_SOCK_DBG("Creating NFS socket for %s port = %d\n", ((struct sockaddr_un*)&ss)->sun_path, port);
                }
                error = nfs_socket_create(nmp, (struct sockaddr*)&ss, nso->nso_sotype, port,
                    NFS_PROG, nfsvers, NMFLAG(nmp, RESVPORT), &nsonfs);
                if (error) {
                        nfs_socket_search_update_error(&nss, error);
                        nfs_socket_destroy(nso);
                        NFS_SOCK_DBG("Could not create NFS socket: %d\n", error);
                        goto keepsearching;
                }
                nsonfs->nso_location = nso->nso_location;
                nsonfs->nso_wake = &nss;
                error = sock_setupcall(nsonfs->nso_so, nfs_connect_upcall, nsonfs);
                if (error) {
                        nfs_socket_search_update_error(&nss, error);
                        nfs_socket_destroy(nsonfs);
                        nfs_socket_destroy(nso);
                        NFS_SOCK_DBG("Could not nfs_connect_upcall: %d", error);
                        goto keepsearching;
                }
                TAILQ_INSERT_TAIL(&nss.nss_socklist, nsonfs, nso_link);
                nss.nss_sockcnt++;
                if ((nfsvers < NFS_VER4) && !(nmp->nm_sockflags & NMSOCK_HASCONNECTED) && !NM_OMATTR_GIVEN(nmp, FH)) {
                        /* Set up socket address and port for MOUNT socket. */
                        error = 0;
                        bcopy(nso->nso_saddr, &ss, nso->nso_saddr->sa_len);
                        port = nmp->nm_mountport;
                        NFS_SOCK_DBG("mount port = %d\n", port);
                        if (ss.ss_family == AF_INET) {
                                ((struct sockaddr_in*)&ss)->sin_port = htons(port);
                        } else if (ss.ss_family == AF_INET6) {
                                ((struct sockaddr_in6*)&ss)->sin6_port = htons(port);
                        } else if (ss.ss_family == AF_LOCAL && nmp->nm_mount_localport) {
                                NFS_SOCK_DBG("Setting mount address to %s port = %d\n", nmp->nm_mount_localport, nmp->nm_mountport);
                                strlcpy(((struct sockaddr_un*)&ss)->sun_path, nmp->nm_mount_localport, sizeof(((struct sockaddr_un*)&ss)->sun_path));
                        }
                        if (!port) {
                                /* Get port/sockaddr for MOUNT version corresponding to NFS version. */
                                /* If NFS version is unknown, optimistically choose for NFSv3. */
                                int mntvers = (nfsvers == NFS_VER2) ? RPCMNT_VER1 : RPCMNT_VER3;
                                int mntproto = (NM_OMFLAG(nmp, MNTUDP) || (nso->nso_sotype == SOCK_DGRAM)) ? IPPROTO_UDP : IPPROTO_TCP;
                                NFS_SOCK_DBG("Looking up mount port with socket %p\n", nso->nso_so);
                                error = nfs_portmap_lookup(nmp, vfs_context_current(), (struct sockaddr*)&ss,
                                    nso->nso_so, RPCPROG_MNT, mntvers, mntproto == IPPROTO_UDP ? SOCK_DGRAM : SOCK_STREAM, timeo);
                        }
                        if (!error) {
                                if (ss.ss_family == AF_INET) {
                                        port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
                                } else if (ss.ss_family == AF_INET6) {
                                        port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
                                } else if (ss.ss_family == AF_LOCAL) {
                                        port = (((struct sockaddr_un*)&ss)->sun_path[0] != '\0');
                                }
                                if (!port) {
                                        error = EPROGUNAVAIL;
                                }
                        }
                        /* create sockaddr for MOUNT */
                        if (!error) {
                                MALLOC(nsonfs->nso_saddr2, struct sockaddr *, ss.ss_len, M_SONAME, M_WAITOK | M_ZERO);
                        }
                        if (!error && !nsonfs->nso_saddr2) {
                                error = ENOMEM;
                        }
                        if (!error) {
                                bcopy(&ss, nsonfs->nso_saddr2, ss.ss_len);
                        }
                        if (error) {
                                NFS_SOCK_DBG("Could not create mount sockaet address %d", error);
                                lck_mtx_lock(&nsonfs->nso_lock);
                                nsonfs->nso_error = error;
                                nsonfs->nso_flags |= NSO_DEAD;
                                lck_mtx_unlock(&nsonfs->nso_lock);
                        }
                }
                NFS_SOCK_DBG("Destroying socket %p so %p\n", nso, nso->nso_so);
                nfs_socket_destroy(nso);
                goto keepsearching;
        }

        /* nso is an NFS socket */
        NFS_SOCK_DBG("nfs connect %s got NFS socket %p\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso);

        /* If NFS version wasn't specified, it was determined during the connect. */
        nfsvers = nmp->nm_vers ? nmp->nm_vers : (int)nso->nso_version;

        /* Perform MOUNT call for initial NFSv2/v3 connection/mount. */
        if ((nfsvers < NFS_VER4) && !(nmp->nm_sockflags & NMSOCK_HASCONNECTED) && !NM_OMATTR_GIVEN(nmp, FH)) {
                error = 0;
                saddr = nso->nso_saddr2;
                if (!saddr) {
                        /* Need sockaddr for MOUNT port */
                        NFS_SOCK_DBG("Getting mount address mountport = %d, mount_localport = %s\n", nmp->nm_mountport, nmp->nm_mount_localport);
                        bcopy(nso->nso_saddr, &ss, nso->nso_saddr->sa_len);
                        port = nmp->nm_mountport;
                        if (ss.ss_family == AF_INET) {
                                ((struct sockaddr_in*)&ss)->sin_port = htons(port);
                        } else if (ss.ss_family == AF_INET6) {
                                ((struct sockaddr_in6*)&ss)->sin6_port = htons(port);
                        } else if (ss.ss_family == AF_LOCAL && nmp->nm_mount_localport) {
                                NFS_SOCK_DBG("Setting mount address to %s port = %d\n", nmp->nm_mount_localport, nmp->nm_mountport);
                                strlcpy(((struct sockaddr_un*)&ss)->sun_path, nmp->nm_mount_localport, sizeof(((struct sockaddr_un*)&ss)->sun_path));
                        }
                        if (!port) {
                                /* Get port/sockaddr for MOUNT version corresponding to NFS version. */
                                int mntvers = (nfsvers == NFS_VER2) ? RPCMNT_VER1 : RPCMNT_VER3;
                                int so_type = NM_OMFLAG(nmp, MNTUDP) ? SOCK_DGRAM : nso->nso_sotype;
                                error = nfs_portmap_lookup(nmp, vfs_context_current(), (struct sockaddr*)&ss,
                                    NULL, RPCPROG_MNT, mntvers, so_type, timeo);
                                if (ss.ss_family == AF_INET) {
                                        port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
                                } else if (ss.ss_family == AF_INET6) {
                                        port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
                                }
                        }
                        if (!error) {
                                if (port) {
                                        saddr = (struct sockaddr*)&ss;
                                } else {
                                        error = EPROGUNAVAIL;
                                }
                        }
                }
                if (saddr) {
                        MALLOC(fh, fhandle_t *, sizeof(fhandle_t), M_TEMP, M_WAITOK | M_ZERO);
                }
                if (saddr && fh) {
                        MALLOC_ZONE(path, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
                }
                if (!saddr || !fh || !path) {
                        if (!error) {
                                error = ENOMEM;
                        }
                        if (fh) {
                                FREE(fh, M_TEMP);
                        }
                        if (path) {
                                FREE_ZONE(path, MAXPATHLEN, M_NAMEI);
                        }
                        fh = NULL;
                        path = NULL;
                        nfs_socket_search_update_error(&nss, error);
                        nfs_socket_destroy(nso);
                        goto keepsearching;
                }
                nfs_location_mntfromname(&nmp->nm_locations, nso->nso_location, path, MAXPATHLEN, 1);
                error = nfs3_mount_rpc(nmp, saddr, nso->nso_sotype, nfsvers,
                    path, vfs_context_current(), timeo, fh, &nmp->nm_servsec);
                NFS_SOCK_DBG("nfs connect %s socket %p mount %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, error);
                if (!error) {
                        /* Make sure we can agree on a security flavor. */
                        int o, s;  /* indices into mount option and server security flavor lists */
                        int found = 0;

                        if ((nfsvers == NFS_VER3) && !nmp->nm_servsec.count) {
                                /* Some servers return an empty list to indicate RPCAUTH_SYS? */
                                nmp->nm_servsec.count = 1;
                                nmp->nm_servsec.flavors[0] = RPCAUTH_SYS;
                        }
                        if (nmp->nm_sec.count) {
                                /* Choose the first flavor in our list that the server supports. */
                                if (!nmp->nm_servsec.count) {
                                        /* we don't know what the server supports, just use our first choice */
                                        nmp->nm_auth = nmp->nm_sec.flavors[0];
                                        found = 1;
                                }
                                for (o = 0; !found && (o < nmp->nm_sec.count); o++) {
                                        for (s = 0; !found && (s < nmp->nm_servsec.count); s++) {
                                                if (nmp->nm_sec.flavors[o] == nmp->nm_servsec.flavors[s]) {
                                                        nmp->nm_auth = nmp->nm_sec.flavors[o];
                                                        found = 1;
                                                }
                                        }
                                }
                        } else {
                                /* Choose the first one we support from the server's list. */
                                if (!nmp->nm_servsec.count) {
                                        nmp->nm_auth = RPCAUTH_SYS;
                                        found = 1;
                                }
                                for (s = 0; s < nmp->nm_servsec.count; s++) {
                                        switch (nmp->nm_servsec.flavors[s]) {
                                        case RPCAUTH_SYS:
                                                /* prefer RPCAUTH_SYS to RPCAUTH_NONE */
                                                if (found && (nmp->nm_auth == RPCAUTH_NONE)) {
                                                        found = 0;
                                                }
                                        case RPCAUTH_NONE:
                                        case RPCAUTH_KRB5:
                                        case RPCAUTH_KRB5I:
                                        case RPCAUTH_KRB5P:
                                                if (!found) {
                                                        nmp->nm_auth = nmp->nm_servsec.flavors[s];
                                                        found = 1;
                                                }
                                                break;
                                        }
                                }
                        }
                        error = !found ? EAUTH : 0;
                }
                FREE_ZONE(path, MAXPATHLEN, M_NAMEI);
                path = NULL;
                if (error) {
                        nfs_socket_search_update_error(&nss, error);
                        FREE(fh, M_TEMP);
                        fh = NULL;
                        nfs_socket_destroy(nso);
                        goto keepsearching;
                }
                if (nmp->nm_fh) {
                        FREE(nmp->nm_fh, M_TEMP);
                }
                nmp->nm_fh = fh;
                fh = NULL;
                NFS_BITMAP_SET(nmp->nm_flags, NFS_MFLAG_CALLUMNT);
        }

        /* put the real upcall in place */
        upcall = (nso->nso_sotype == SOCK_STREAM) ? nfs_tcp_rcv : nfs_udp_rcv;
        error = sock_setupcall(nso->nso_so, upcall, nmp);
        if (error) {
                nfs_socket_search_update_error(&nss, error);
                nfs_socket_destroy(nso);
                goto keepsearching;
        }

        if (!(nmp->nm_sockflags & NMSOCK_HASCONNECTED)) {
                /* set mntfromname to this location */
                if (!NM_OMATTR_GIVEN(nmp, MNTFROM)) {
                        nfs_location_mntfromname(&nmp->nm_locations, nso->nso_location,
                            vfs_statfs(nmp->nm_mountp)->f_mntfromname,
                            sizeof(vfs_statfs(nmp->nm_mountp)->f_mntfromname), 0);
                }
                /* some negotiated values need to remain unchanged for the life of the mount */
                if (!nmp->nm_sotype) {
                        nmp->nm_sotype = nso->nso_sotype;
                }
                if (!nmp->nm_vers) {
                        nmp->nm_vers = nfsvers;
#if CONFIG_NFS4
                        /* If we negotiated NFSv4, set nm_nfsport if we ended up on the standard NFS port */
                        if ((nfsvers >= NFS_VER4) && !NFS_BITMAP_ISSET(nmp->nm_mattrs, NFS_MATTR_NFS_PORT)) {
                                if (nso->nso_saddr->sa_family == AF_INET) {
                                        port = ((struct sockaddr_in*)nso->nso_saddr)->sin_port = htons(port);
                                } else if (nso->nso_saddr->sa_family == AF_INET6) {
                                        port = ((struct sockaddr_in6*)nso->nso_saddr)->sin6_port = htons(port);
                                } else {
                                        port = 0;
                                }
                                if (port == NFS_PORT) {
                                        nmp->nm_nfsport = NFS_PORT;
                                }
                        }
#endif
                }
#if CONFIG_NFS4
                /* do some version-specific pre-mount set up */
                if (nmp->nm_vers >= NFS_VER4) {
                        microtime(&now);
                        nmp->nm_mounttime = ((uint64_t)now.tv_sec << 32) | now.tv_usec;
                        if (!NMFLAG(nmp, NOCALLBACK)) {
                                nfs4_mount_callback_setup(nmp);
                        }
                }
#endif
        }

        /* Initialize NFS socket state variables */
        lck_mtx_lock(&nmp->nm_lock);
        nmp->nm_srtt[0] = nmp->nm_srtt[1] = nmp->nm_srtt[2] =
            nmp->nm_srtt[3] = (NFS_TIMEO << 3);
        nmp->nm_sdrtt[0] = nmp->nm_sdrtt[1] = nmp->nm_sdrtt[2] =
            nmp->nm_sdrtt[3] = 0;
        if (nso->nso_sotype == SOCK_DGRAM) {
                nmp->nm_cwnd = NFS_MAXCWND / 2;     /* Initial send window */
                nmp->nm_sent = 0;
        } else if (nso->nso_sotype == SOCK_STREAM) {
                nmp->nm_timeouts = 0;
        }
        nmp->nm_sockflags &= ~NMSOCK_CONNECTING;
        nmp->nm_sockflags |= NMSOCK_SETUP;
        /* move the socket to the mount structure */
        nmp->nm_nso = nso;
        oldsaddr = nmp->nm_saddr;
        nmp->nm_saddr = nso->nso_saddr;
        lck_mtx_unlock(&nmp->nm_lock);
        error = nfs_connect_setup(nmp);
        lck_mtx_lock(&nmp->nm_lock);
        nmp->nm_sockflags &= ~NMSOCK_SETUP;
        if (!error) {
                nmp->nm_sockflags |= NMSOCK_READY;
                wakeup(&nmp->nm_sockflags);
        }
        if (error) {
                NFS_SOCK_DBG("nfs connect %s socket %p setup failed %d\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, nso, error);
                nfs_socket_search_update_error(&nss, error);
                nmp->nm_saddr = oldsaddr;
                if (!(nmp->nm_sockflags & NMSOCK_HASCONNECTED)) {
                        /* undo settings made prior to setup */
                        if (!NFS_BITMAP_ISSET(nmp->nm_mattrs, NFS_MATTR_SOCKET_TYPE)) {
                                nmp->nm_sotype = 0;
                        }
                        if (!NFS_BITMAP_ISSET(nmp->nm_mattrs, NFS_MATTR_NFS_VERSION)) {
#if CONFIG_NFS4
                                if (nmp->nm_vers >= NFS_VER4) {
                                        if (!NFS_BITMAP_ISSET(nmp->nm_mattrs, NFS_MATTR_NFS_PORT)) {
                                                nmp->nm_nfsport = 0;
                                        }
                                        if (nmp->nm_cbid) {
                                                nfs4_mount_callback_shutdown(nmp);
                                        }
                                        if (IS_VALID_CRED(nmp->nm_mcred)) {
                                                kauth_cred_unref(&nmp->nm_mcred);
                                        }
                                        bzero(&nmp->nm_un, sizeof(nmp->nm_un));
                                }
#endif
                                nmp->nm_vers = 0;
                        }
                }
                lck_mtx_unlock(&nmp->nm_lock);
                nmp->nm_nso = NULL;
                nfs_socket_destroy(nso);
                goto keepsearching;
        }

        /* update current location */
        if ((nmp->nm_locations.nl_current.nli_flags & NLI_VALID) &&
            (nmp->nm_locations.nl_current.nli_serv != nso->nso_location.nli_serv)) {
                /* server has changed, we should initiate failover/recovery */
                // XXX
        }
        nmp->nm_locations.nl_current = nso->nso_location;
        nmp->nm_locations.nl_current.nli_flags |= NLI_VALID;

        if (!(nmp->nm_sockflags & NMSOCK_HASCONNECTED)) {
                /* We have now successfully connected... make a note of it. */
                nmp->nm_sockflags |= NMSOCK_HASCONNECTED;
        }

        lck_mtx_unlock(&nmp->nm_lock);
        if (oldsaddr) {
                FREE(oldsaddr, M_SONAME);
        }

        if (nss.nss_flags & NSS_WARNED) {
                log(LOG_INFO, "nfs_connect: socket connect completed for %s\n",
                    vfs_statfs(nmp->nm_mountp)->f_mntfromname);
        }

        nmp->nm_nss = NULL;
        nfs_socket_search_cleanup(&nss);
        if (fh) {
                FREE(fh, M_TEMP);
        }
        if (path) {
                FREE_ZONE(path, MAXPATHLEN, M_NAMEI);
        }
        NFS_SOCK_DBG("nfs connect %s success\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname);
        return 0;
}


/* setup & confirm socket connection is functional */
int
nfs_connect_setup(
#if !CONFIG_NFS4
        __unused
#endif
        struct nfsmount *nmp)
{
        int error = 0;
#if CONFIG_NFS4
        if (nmp->nm_vers >= NFS_VER4) {
                if (nmp->nm_state & NFSSTA_CLIENTID) {
                        /* first, try to renew our current state */
                        error = nfs4_renew(nmp, R_SETUP);
                        if ((error == NFSERR_ADMIN_REVOKED) ||
                            (error == NFSERR_CB_PATH_DOWN) ||
                            (error == NFSERR_EXPIRED) ||
                            (error == NFSERR_LEASE_MOVED) ||
                            (error == NFSERR_STALE_CLIENTID)) {
                                lck_mtx_lock(&nmp->nm_lock);
                                nfs_need_recover(nmp, error);
                                lck_mtx_unlock(&nmp->nm_lock);
                        }
                }
                error = nfs4_setclientid(nmp);
        }
#endif
        return error;
}

/*
 * NFS socket reconnect routine:
 * Called when a connection is broken.
 * - disconnect the old socket
 * - nfs_connect() again
 * - set R_MUSTRESEND for all outstanding requests on mount point
 * If this fails the mount point is DEAD!
 */
int
nfs_reconnect(struct nfsmount *nmp)
{
        struct nfsreq *rq;
        struct timeval now;
        thread_t thd = current_thread();
        int error, wentdown = 0, verbose = 1;
        time_t lastmsg;
        int timeo;

        microuptime(&now);
        lastmsg = now.tv_sec - (nmp->nm_tprintf_delay - nmp->nm_tprintf_initial_delay);

        nfs_disconnect(nmp);


        lck_mtx_lock(&nmp->nm_lock);
        timeo = nfs_is_squishy(nmp) ? 8 : 30;
        lck_mtx_unlock(&nmp->nm_lock);

        while ((error = nfs_connect(nmp, verbose, timeo))) {
                verbose = 0;
                nfs_disconnect(nmp);
                if ((error == EINTR) || (error == ERESTART)) {
                        return EINTR;
                }
                if (error == EIO) {
                        return EIO;
                }
                microuptime(&now);
                if ((lastmsg + nmp->nm_tprintf_delay) < now.tv_sec) {
                        lastmsg = now.tv_sec;
                        nfs_down(nmp, thd, error, NFSSTA_TIMEO, "can not connect", 0);
                        wentdown = 1;
                }
                lck_mtx_lock(&nmp->nm_lock);
                if (!(nmp->nm_state & NFSSTA_MOUNTED)) {
                        /* we're not yet completely mounted and */
                        /* we can't reconnect, so we fail */
                        lck_mtx_unlock(&nmp->nm_lock);
                        NFS_SOCK_DBG("Not mounted returning %d\n", error);
                        return error;
                }

                if (nfs_mount_check_dead_timeout(nmp)) {
                        nfs_mount_make_zombie(nmp);
                        lck_mtx_unlock(&nmp->nm_lock);
                        return ENXIO;
                }

                if ((error = nfs_sigintr(nmp, NULL, thd, 1))) {
                        lck_mtx_unlock(&nmp->nm_lock);
                        return error;
                }
                lck_mtx_unlock(&nmp->nm_lock);
                tsleep(nfs_reconnect, PSOCK, "nfs_reconnect_delay", 2 * hz);
                if ((error = nfs_sigintr(nmp, NULL, thd, 0))) {
                        return error;
                }
        }

        if (wentdown) {
                nfs_up(nmp, thd, NFSSTA_TIMEO, "connected");
        }

        /*
         * Loop through outstanding request list and mark all requests
         * as needing a resend.  (Though nfs_need_reconnect() probably
         * marked them all already.)
         */
        lck_mtx_lock(nfs_request_mutex);
        TAILQ_FOREACH(rq, &nfs_reqq, r_chain) {
                if (rq->r_nmp == nmp) {
                        lck_mtx_lock(&rq->r_mtx);
                        if (!rq->r_error && !rq->r_nmrep.nmc_mhead && !(rq->r_flags & R_MUSTRESEND)) {
                                rq->r_flags |= R_MUSTRESEND;
                                rq->r_rtt = -1;
                                wakeup(rq);
                                if ((rq->r_flags & (R_IOD | R_ASYNC | R_ASYNCWAIT | R_SENDING)) == R_ASYNC) {
                                        nfs_asyncio_resend(rq);
                                }
                        }
                        lck_mtx_unlock(&rq->r_mtx);
                }
        }
        lck_mtx_unlock(nfs_request_mutex);
        return 0;
}

/*
 * NFS disconnect. Clean up and unlink.
 */
void
nfs_disconnect(struct nfsmount *nmp)
{
        struct nfs_socket *nso;

        lck_mtx_lock(&nmp->nm_lock);
tryagain:
        if (nmp->nm_nso) {
                struct timespec ts = { .tv_sec = 1, .tv_nsec = 0 };
                if (nmp->nm_state & NFSSTA_SENDING) { /* wait for sending to complete */
                        nmp->nm_state |= NFSSTA_WANTSND;
                        msleep(&nmp->nm_state, &nmp->nm_lock, PZERO - 1, "nfswaitsending", &ts);
                        goto tryagain;
                }
                if (nmp->nm_sockflags & NMSOCK_POKE) { /* wait for poking to complete */
                        msleep(&nmp->nm_sockflags, &nmp->nm_lock, PZERO - 1, "nfswaitpoke", &ts);
                        goto tryagain;
                }
                nmp->nm_sockflags |= NMSOCK_DISCONNECTING;
                nmp->nm_sockflags &= ~NMSOCK_READY;
                nso = nmp->nm_nso;
                nmp->nm_nso = NULL;
                if (nso->nso_saddr == nmp->nm_saddr) {
                        nso->nso_saddr = NULL;
                }
                lck_mtx_unlock(&nmp->nm_lock);
                nfs_socket_destroy(nso);
                lck_mtx_lock(&nmp->nm_lock);
                nmp->nm_sockflags &= ~NMSOCK_DISCONNECTING;
                lck_mtx_unlock(&nmp->nm_lock);
        } else {
                lck_mtx_unlock(&nmp->nm_lock);
        }
}

/*
 * mark an NFS mount as needing a reconnect/resends.
 */
void
nfs_need_reconnect(struct nfsmount *nmp)
{
        struct nfsreq *rq;

        lck_mtx_lock(&nmp->nm_lock);
        nmp->nm_sockflags &= ~(NMSOCK_READY | NMSOCK_SETUP);
        lck_mtx_unlock(&nmp->nm_lock);

        /*
         * Loop through outstanding request list and
         * mark all requests as needing a resend.
         */
        lck_mtx_lock(nfs_request_mutex);
        TAILQ_FOREACH(rq, &nfs_reqq, r_chain) {
                if (rq->r_nmp == nmp) {
                        lck_mtx_lock(&rq->r_mtx);
                        if (!rq->r_error && !rq->r_nmrep.nmc_mhead && !(rq->r_flags & R_MUSTRESEND)) {
                                rq->r_flags |= R_MUSTRESEND;
                                rq->r_rtt = -1;
                                wakeup(rq);
                                if ((rq->r_flags & (R_IOD | R_ASYNC | R_ASYNCWAIT | R_SENDING)) == R_ASYNC) {
                                        nfs_asyncio_resend(rq);
                                }
                        }
                        lck_mtx_unlock(&rq->r_mtx);
                }
        }
        lck_mtx_unlock(nfs_request_mutex);
}


/*
 * thread to handle miscellaneous async NFS socket work (reconnects/resends)
 */
void
nfs_mount_sock_thread(void *arg, __unused wait_result_t wr)
{
        struct nfsmount *nmp = arg;
        struct timespec ts = { .tv_sec = 30, .tv_nsec = 0 };
        thread_t thd = current_thread();
        struct nfsreq *req;
        struct timeval now;
        int error, dofinish;
        nfsnode_t np;
        int do_reconnect_sleep = 0;

        lck_mtx_lock(&nmp->nm_lock);
        while (!(nmp->nm_sockflags & NMSOCK_READY) ||
            !TAILQ_EMPTY(&nmp->nm_resendq) ||
            !LIST_EMPTY(&nmp->nm_monlist) ||
            nmp->nm_deadto_start ||
            (nmp->nm_state & NFSSTA_RECOVER) ||
            ((nmp->nm_vers >= NFS_VER4) && !TAILQ_EMPTY(&nmp->nm_dreturnq))) {
                if (nmp->nm_sockflags & NMSOCK_UNMOUNT) {
                        break;
                }
                /* do reconnect, if necessary */
                if (!(nmp->nm_sockflags & NMSOCK_READY) && !(nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD))) {
                        if (nmp->nm_reconnect_start <= 0) {
                                microuptime(&now);
                                nmp->nm_reconnect_start = now.tv_sec;
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                        NFS_SOCK_DBG("nfs reconnect %s\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                        /*
                         * XXX We don't want to call reconnect again right away if returned errors
                         * before that may not have blocked. This has caused spamming null procs
                         * from machines in the pass.
                         */
                        if (do_reconnect_sleep) {
                                tsleep(nfs_mount_sock_thread, PSOCK, "nfs_reconnect_sock_thread_delay", hz);
                        }
                        error = nfs_reconnect(nmp);
                        if (error) {
                                int lvl = 7;
                                if (error == EIO || error == EINTR) {
                                        lvl = (do_reconnect_sleep++ % 600) ? 7 : 0;
                                }
                                NFS_DBG(NFS_FAC_SOCK, lvl, "nfs reconnect %s: returned %d\n",
                                    vfs_statfs(nmp->nm_mountp)->f_mntfromname, error);
                        } else {
                                nmp->nm_reconnect_start = 0;
                                do_reconnect_sleep = 0;
                        }
                        lck_mtx_lock(&nmp->nm_lock);
                }
                if ((nmp->nm_sockflags & NMSOCK_READY) &&
                    (nmp->nm_state & NFSSTA_RECOVER) &&
                    !(nmp->nm_sockflags & NMSOCK_UNMOUNT) &&
                    !(nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD))) {
                        /* perform state recovery */
                        lck_mtx_unlock(&nmp->nm_lock);
                        nfs_recover(nmp);
                        lck_mtx_lock(&nmp->nm_lock);
                }
#if CONFIG_NFS4
                /* handle NFSv4 delegation returns */
                while ((nmp->nm_vers >= NFS_VER4) && !(nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD)) &&
                    (nmp->nm_sockflags & NMSOCK_READY) && !(nmp->nm_state & NFSSTA_RECOVER) &&
                    ((np = TAILQ_FIRST(&nmp->nm_dreturnq)))) {
                        lck_mtx_unlock(&nmp->nm_lock);
                        nfs4_delegation_return(np, R_RECOVER, thd, nmp->nm_mcred);
                        lck_mtx_lock(&nmp->nm_lock);
                }
#endif
                /* do resends, if necessary/possible */
                while ((((nmp->nm_sockflags & NMSOCK_READY) && !(nmp->nm_state & NFSSTA_RECOVER)) ||
                    (nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD))) &&
                    ((req = TAILQ_FIRST(&nmp->nm_resendq)))) {
                        if (req->r_resendtime) {
                                microuptime(&now);
                        }
                        while (req && !(nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD)) && req->r_resendtime && (now.tv_sec < req->r_resendtime)) {
                                req = TAILQ_NEXT(req, r_rchain);
                        }
                        if (!req) {
                                break;
                        }
                        TAILQ_REMOVE(&nmp->nm_resendq, req, r_rchain);
                        req->r_rchain.tqe_next = NFSREQNOLIST;
                        lck_mtx_unlock(&nmp->nm_lock);
                        lck_mtx_lock(&req->r_mtx);
                        /* Note that we have a reference on the request that was taken nfs_asyncio_resend */
                        if (req->r_error || req->r_nmrep.nmc_mhead) {
                                dofinish = req->r_callback.rcb_func && !(req->r_flags & R_WAITSENT);
                                req->r_flags &= ~R_RESENDQ;
                                wakeup(req);
                                lck_mtx_unlock(&req->r_mtx);
                                if (dofinish) {
                                        nfs_asyncio_finish(req);
                                }
                                nfs_request_rele(req);
                                lck_mtx_lock(&nmp->nm_lock);
                                continue;
                        }
                        if ((req->r_flags & R_RESTART) || nfs_request_using_gss(req)) {
                                req->r_flags &= ~R_RESTART;
                                req->r_resendtime = 0;
                                lck_mtx_unlock(&req->r_mtx);
                                /* async RPCs on GSS mounts need to be rebuilt and resent. */
                                nfs_reqdequeue(req);
#if CONFIG_NFS_GSS
                                if (nfs_request_using_gss(req)) {
                                        nfs_gss_clnt_rpcdone(req);
                                        error = nfs_gss_clnt_args_restore(req);
                                        if (error == ENEEDAUTH) {
                                                req->r_xid = 0;
                                        }
                                }
#endif /* CONFIG_NFS_GSS */
                                NFS_SOCK_DBG("nfs async%s restart: p %d x 0x%llx f 0x%x rtt %d\n",
                                    nfs_request_using_gss(req) ? " gss" : "", req->r_procnum, req->r_xid,
                                    req->r_flags, req->r_rtt);
                                error = nfs_sigintr(nmp, req, req->r_thread, 0);
                                if (!error) {
                                        error = nfs_request_add_header(req);
                                }
                                if (!error) {
                                        error = nfs_request_send(req, 0);
                                }
                                lck_mtx_lock(&req->r_mtx);
                                if (req->r_flags & R_RESENDQ) {
                                        req->r_flags &= ~R_RESENDQ;
                                }
                                if (error) {
                                        req->r_error = error;
                                }
                                wakeup(req);
                                dofinish = error && req->r_callback.rcb_func && !(req->r_flags & R_WAITSENT);
                                lck_mtx_unlock(&req->r_mtx);
                                if (dofinish) {
                                        nfs_asyncio_finish(req);
                                }
                                nfs_request_rele(req);
                                lck_mtx_lock(&nmp->nm_lock);
                                error = 0;
                                continue;
                        }
                        NFS_SOCK_DBG("nfs async resend: p %d x 0x%llx f 0x%x rtt %d\n",
                            req->r_procnum, req->r_xid, req->r_flags, req->r_rtt);
                        error = nfs_sigintr(nmp, req, req->r_thread, 0);
                        if (!error) {
                                req->r_flags |= R_SENDING;
                                lck_mtx_unlock(&req->r_mtx);
                                error = nfs_send(req, 0);
                                lck_mtx_lock(&req->r_mtx);
                                if (!error) {
                                        if (req->r_flags & R_RESENDQ) {
                                                req->r_flags &= ~R_RESENDQ;
                                        }
                                        wakeup(req);
                                        lck_mtx_unlock(&req->r_mtx);
                                        nfs_request_rele(req);
                                        lck_mtx_lock(&nmp->nm_lock);
                                        continue;
                                }
                        }
                        req->r_error = error;
                        if (req->r_flags & R_RESENDQ) {
                                req->r_flags &= ~R_RESENDQ;
                        }
                        wakeup(req);
                        dofinish = req->r_callback.rcb_func && !(req->r_flags & R_WAITSENT);
                        lck_mtx_unlock(&req->r_mtx);
                        if (dofinish) {
                                nfs_asyncio_finish(req);
                        }
                        nfs_request_rele(req);
                        lck_mtx_lock(&nmp->nm_lock);
                }
                if (nfs_mount_check_dead_timeout(nmp)) {
                        nfs_mount_make_zombie(nmp);
                        break;
                }

                if (nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD)) {
                        break;
                }
                /* check monitored nodes, if necessary/possible */
                if (!LIST_EMPTY(&nmp->nm_monlist)) {
                        nmp->nm_state |= NFSSTA_MONITOR_SCAN;
                        LIST_FOREACH(np, &nmp->nm_monlist, n_monlink) {
                                if (!(nmp->nm_sockflags & NMSOCK_READY) ||
                                    (nmp->nm_state & (NFSSTA_RECOVER | NFSSTA_UNMOUNTING | NFSSTA_FORCE | NFSSTA_DEAD))) {
                                        break;
                                }
                                np->n_mflag |= NMMONSCANINPROG;
                                lck_mtx_unlock(&nmp->nm_lock);
                                error = nfs_getattr(np, NULL, vfs_context_kernel(), (NGA_UNCACHED | NGA_MONITOR));
                                if (!error && ISSET(np->n_flag, NUPDATESIZE)) { /* update quickly to avoid multiple events */
                                        nfs_data_update_size(np, 0);
                                }
                                lck_mtx_lock(&nmp->nm_lock);
                                np->n_mflag &= ~NMMONSCANINPROG;
                                if (np->n_mflag & NMMONSCANWANT) {
                                        np->n_mflag &= ~NMMONSCANWANT;
                                        wakeup(&np->n_mflag);
                                }
                                if (error || !(nmp->nm_sockflags & NMSOCK_READY) ||
                                    (nmp->nm_state & (NFSSTA_RECOVER | NFSSTA_UNMOUNTING | NFSSTA_FORCE | NFSSTA_DEAD))) {
                                        break;
                                }
                        }
                        nmp->nm_state &= ~NFSSTA_MONITOR_SCAN;
                        if (nmp->nm_state & NFSSTA_UNMOUNTING) {
                                wakeup(&nmp->nm_state); /* let unmounting thread know scan is done */
                        }
                }
                if ((nmp->nm_sockflags & NMSOCK_READY) || (nmp->nm_state & (NFSSTA_RECOVER | NFSSTA_UNMOUNTING))) {
                        if (nmp->nm_deadto_start || !TAILQ_EMPTY(&nmp->nm_resendq) ||
                            (nmp->nm_state & NFSSTA_RECOVER)) {
                                ts.tv_sec = 1;
                        } else {
                                ts.tv_sec = 5;
                        }
                        msleep(&nmp->nm_sockthd, &nmp->nm_lock, PSOCK, "nfssockthread", &ts);
                }
        }

        /* If we're unmounting, send the unmount RPC, if requested/appropriate. */
        if ((nmp->nm_sockflags & NMSOCK_UNMOUNT) &&
            (nmp->nm_state & NFSSTA_MOUNTED) && NMFLAG(nmp, CALLUMNT) &&
            (nmp->nm_vers < NFS_VER4) && !(nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD))) {
                lck_mtx_unlock(&nmp->nm_lock);
                nfs3_umount_rpc(nmp, vfs_context_kernel(),
                    (nmp->nm_sockflags & NMSOCK_READY) ? 6 : 2);
                lck_mtx_lock(&nmp->nm_lock);
        }

        if (nmp->nm_sockthd == thd) {
                nmp->nm_sockthd = NULL;
        }
        lck_mtx_unlock(&nmp->nm_lock);
        wakeup(&nmp->nm_sockthd);
        thread_terminate(thd);
}

/* start or wake a mount's socket thread */
void
nfs_mount_sock_thread_wake(struct nfsmount *nmp)
{
        if (nmp->nm_sockthd) {
                wakeup(&nmp->nm_sockthd);
        } else if (kernel_thread_start(nfs_mount_sock_thread, nmp, &nmp->nm_sockthd) == KERN_SUCCESS) {
                thread_deallocate(nmp->nm_sockthd);
        }
}

/*
 * Check if we should mark the mount dead because the
 * unresponsive mount has reached the dead timeout.
 * (must be called with nmp locked)
 */
int
nfs_mount_check_dead_timeout(struct nfsmount *nmp)
{
        struct timeval now;

        if (nmp->nm_state & NFSSTA_DEAD) {
                return 1;
        }
        if (nmp->nm_deadto_start == 0) {
                return 0;
        }
        nfs_is_squishy(nmp);
        if (nmp->nm_curdeadtimeout <= 0) {
                return 0;
        }
        microuptime(&now);
        if ((now.tv_sec - nmp->nm_deadto_start) < nmp->nm_curdeadtimeout) {
                return 0;
        }
        return 1;
}

/*
 * Call nfs_mount_zombie to remove most of the
 * nfs state for the mount, and then ask to be forcibly unmounted.
 *
 * Assumes the nfs mount structure lock nm_lock is held.
 */

void
nfs_mount_make_zombie(struct nfsmount *nmp)
{
        fsid_t fsid;

        if (!nmp) {
                return;
        }

        if (nmp->nm_state & NFSSTA_DEAD) {
                return;
        }

        printf("nfs server %s: %sdead\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname,
            (nmp->nm_curdeadtimeout != nmp->nm_deadtimeout) ? "squished " : "");
        fsid = vfs_statfs(nmp->nm_mountp)->f_fsid;
        lck_mtx_unlock(&nmp->nm_lock);
        nfs_mount_zombie(nmp, NFSSTA_DEAD);
        vfs_event_signal(&fsid, VQ_DEAD, 0);
        lck_mtx_lock(&nmp->nm_lock);
}


/*
 * NFS callback channel socket state
 */
struct nfs_callback_socket {
        TAILQ_ENTRY(nfs_callback_socket) ncbs_link;
        socket_t                        ncbs_so;        /* the socket */
        struct sockaddr_storage         ncbs_saddr;     /* socket address */
        struct nfs_rpc_record_state     ncbs_rrs;       /* RPC record parsing state */
        time_t                          ncbs_stamp;     /* last accessed at */
        uint32_t                        ncbs_flags;     /* see below */
};
#define NCBSOCK_UPCALL          0x0001
#define NCBSOCK_UPCALLWANT      0x0002
#define NCBSOCK_DEAD            0x0004

#if CONFIG_NFS4
/*
 * NFS callback channel state
 *
 * One listening socket for accepting socket connections from servers and
 * a list of connected sockets to handle callback requests on.
 * Mounts registered with the callback channel are assigned IDs and
 * put on a list so that the callback request handling code can match
 * the requests up with mounts.
 */
socket_t nfs4_cb_so = NULL;
socket_t nfs4_cb_so6 = NULL;
in_port_t nfs4_cb_port = 0;
in_port_t nfs4_cb_port6 = 0;
uint32_t nfs4_cb_id = 0;
uint32_t nfs4_cb_so_usecount = 0;
TAILQ_HEAD(nfs4_cb_sock_list, nfs_callback_socket) nfs4_cb_socks;
TAILQ_HEAD(nfs4_cb_mount_list, nfsmount) nfs4_cb_mounts;

int nfs4_cb_handler(struct nfs_callback_socket *, mbuf_t);

/*
 * Set up the callback channel for the NFS mount.
 *
 * Initializes the callback channel socket state and
 * assigns a callback ID to the mount.
 */
void
nfs4_mount_callback_setup(struct nfsmount *nmp)
{
        struct sockaddr_in sin;
        struct sockaddr_in6 sin6;
        socket_t so = NULL;
        socket_t so6 = NULL;
        struct timeval timeo;
        int error, on = 1;
        in_port_t port;

        lck_mtx_lock(nfs_global_mutex);
        if (nfs4_cb_id == 0) {
                TAILQ_INIT(&nfs4_cb_mounts);
                TAILQ_INIT(&nfs4_cb_socks);
                nfs4_cb_id++;
        }
        nmp->nm_cbid = nfs4_cb_id++;
        if (nmp->nm_cbid == 0) {
                nmp->nm_cbid = nfs4_cb_id++;
        }
        nfs4_cb_so_usecount++;
        TAILQ_INSERT_HEAD(&nfs4_cb_mounts, nmp, nm_cblink);

        if (nfs4_cb_so) {
                lck_mtx_unlock(nfs_global_mutex);
                return;
        }

        /* IPv4 */
        error = sock_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP, nfs4_cb_accept, NULL, &nfs4_cb_so);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d creating listening IPv4 socket\n", error);
                goto fail;
        }
        so = nfs4_cb_so;

        sock_setsockopt(so, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
        sin.sin_len = sizeof(struct sockaddr_in);
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = htonl(INADDR_ANY);
        sin.sin_port = htons(nfs_callback_port); /* try to use specified port */
        error = sock_bind(so, (struct sockaddr *)&sin);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d binding listening IPv4 socket\n", error);
                goto fail;
        }
        error = sock_getsockname(so, (struct sockaddr *)&sin, sin.sin_len);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d getting listening IPv4 socket port\n", error);
                goto fail;
        }
        nfs4_cb_port = ntohs(sin.sin_port);

        error = sock_listen(so, 32);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d on IPv4 listen\n", error);
                goto fail;
        }

        /* receive timeout shouldn't matter.  If timeout on send, we'll want to drop the socket */
        timeo.tv_usec = 0;
        timeo.tv_sec = 60;
        error = sock_setsockopt(so, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d setting IPv4 socket rx timeout\n", error);
        }
        error = sock_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d setting IPv4 socket tx timeout\n", error);
        }
        sock_setsockopt(so, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
        sock_setsockopt(so, SOL_SOCKET, SO_NOADDRERR, &on, sizeof(on));
        sock_setsockopt(so, SOL_SOCKET, SO_UPCALLCLOSEWAIT, &on, sizeof(on));
        error = 0;

        /* IPv6 */
        error = sock_socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP, nfs4_cb_accept, NULL, &nfs4_cb_so6);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d creating listening IPv6 socket\n", error);
                goto fail;
        }
        so6 = nfs4_cb_so6;

        sock_setsockopt(so6, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
        sock_setsockopt(so6, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
        /* try to use specified port or same port as IPv4 */
        port = nfs_callback_port ? nfs_callback_port : nfs4_cb_port;
ipv6_bind_again:
        sin6.sin6_len = sizeof(struct sockaddr_in6);
        sin6.sin6_family = AF_INET6;
        sin6.sin6_addr = in6addr_any;
        sin6.sin6_port = htons(port);
        error = sock_bind(so6, (struct sockaddr *)&sin6);
        if (error) {
                if (port != nfs_callback_port) {
                        /* if we simply tried to match the IPv4 port, then try any port */
                        port = 0;
                        goto ipv6_bind_again;
                }
                log(LOG_INFO, "nfs callback setup: error %d binding listening IPv6 socket\n", error);
                goto fail;
        }
        error = sock_getsockname(so6, (struct sockaddr *)&sin6, sin6.sin6_len);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d getting listening IPv6 socket port\n", error);
                goto fail;
        }
        nfs4_cb_port6 = ntohs(sin6.sin6_port);

        error = sock_listen(so6, 32);
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d on IPv6 listen\n", error);
                goto fail;
        }

        /* receive timeout shouldn't matter.  If timeout on send, we'll want to drop the socket */
        timeo.tv_usec = 0;
        timeo.tv_sec = 60;
        error = sock_setsockopt(so6, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d setting IPv6 socket rx timeout\n", error);
        }
        error = sock_setsockopt(so6, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback setup: error %d setting IPv6 socket tx timeout\n", error);
        }
        sock_setsockopt(so6, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
        sock_setsockopt(so6, SOL_SOCKET, SO_NOADDRERR, &on, sizeof(on));
        sock_setsockopt(so6, SOL_SOCKET, SO_UPCALLCLOSEWAIT, &on, sizeof(on));
        error = 0;

fail:
        if (error) {
                nfs4_cb_so = nfs4_cb_so6 = NULL;
                lck_mtx_unlock(nfs_global_mutex);
                if (so) {
                        sock_shutdown(so, SHUT_RDWR);
                        sock_close(so);
                }
                if (so6) {
                        sock_shutdown(so6, SHUT_RDWR);
                        sock_close(so6);
                }
        } else {
                lck_mtx_unlock(nfs_global_mutex);
        }
}

/*
 * Shut down the callback channel for the NFS mount.
 *
 * Clears the mount's callback ID and releases the mounts
 * reference on the callback socket.  Last reference dropped
 * will also shut down the callback socket(s).
 */
void
nfs4_mount_callback_shutdown(struct nfsmount *nmp)
{
        struct nfs_callback_socket *ncbsp;
        socket_t so, so6;
        struct nfs4_cb_sock_list cb_socks;
        struct timespec ts = { .tv_sec = 1, .tv_nsec = 0 };

        lck_mtx_lock(nfs_global_mutex);
        TAILQ_REMOVE(&nfs4_cb_mounts, nmp, nm_cblink);
        /* wait for any callbacks in progress to complete */
        while (nmp->nm_cbrefs) {
                msleep(&nmp->nm_cbrefs, nfs_global_mutex, PSOCK, "cbshutwait", &ts);
        }
        nmp->nm_cbid = 0;
        if (--nfs4_cb_so_usecount) {
                lck_mtx_unlock(nfs_global_mutex);
                return;
        }
        so = nfs4_cb_so;
        so6 = nfs4_cb_so6;
        nfs4_cb_so = nfs4_cb_so6 = NULL;
        TAILQ_INIT(&cb_socks);
        TAILQ_CONCAT(&cb_socks, &nfs4_cb_socks, ncbs_link);
        lck_mtx_unlock(nfs_global_mutex);
        if (so) {
                sock_shutdown(so, SHUT_RDWR);
                sock_close(so);
        }
        if (so6) {
                sock_shutdown(so6, SHUT_RDWR);
                sock_close(so6);
        }
        while ((ncbsp = TAILQ_FIRST(&cb_socks))) {
                TAILQ_REMOVE(&cb_socks, ncbsp, ncbs_link);
                sock_shutdown(ncbsp->ncbs_so, SHUT_RDWR);
                sock_close(ncbsp->ncbs_so);
                nfs_rpc_record_state_cleanup(&ncbsp->ncbs_rrs);
                FREE(ncbsp, M_TEMP);
        }
}

/*
 * Check periodically for stale/unused nfs callback sockets
 */
#define NFS4_CB_TIMER_PERIOD    30
#define NFS4_CB_IDLE_MAX        300
void
nfs4_callback_timer(__unused void *param0, __unused void *param1)
{
        struct nfs_callback_socket *ncbsp, *nextncbsp;
        struct timeval now;

loop:
        lck_mtx_lock(nfs_global_mutex);
        if (TAILQ_EMPTY(&nfs4_cb_socks)) {
                nfs4_callback_timer_on = 0;
                lck_mtx_unlock(nfs_global_mutex);
                return;
        }
        microuptime(&now);
        TAILQ_FOREACH_SAFE(ncbsp, &nfs4_cb_socks, ncbs_link, nextncbsp) {
                if (!(ncbsp->ncbs_flags & NCBSOCK_DEAD) &&
                    (now.tv_sec < (ncbsp->ncbs_stamp + NFS4_CB_IDLE_MAX))) {
                        continue;
                }
                TAILQ_REMOVE(&nfs4_cb_socks, ncbsp, ncbs_link);
                lck_mtx_unlock(nfs_global_mutex);
                sock_shutdown(ncbsp->ncbs_so, SHUT_RDWR);
                sock_close(ncbsp->ncbs_so);
                nfs_rpc_record_state_cleanup(&ncbsp->ncbs_rrs);
                FREE(ncbsp, M_TEMP);
                goto loop;
        }
        nfs4_callback_timer_on = 1;
        nfs_interval_timer_start(nfs4_callback_timer_call,
            NFS4_CB_TIMER_PERIOD * 1000);
        lck_mtx_unlock(nfs_global_mutex);
}

/*
 * Accept a new callback socket.
 */
void
nfs4_cb_accept(socket_t so, __unused void *arg, __unused int waitflag)
{
        socket_t newso = NULL;
        struct nfs_callback_socket *ncbsp;
        struct nfsmount *nmp;
        struct timeval timeo, now;
        int error, on = 1, ip;

        if (so == nfs4_cb_so) {
                ip = 4;
        } else if (so == nfs4_cb_so6) {
                ip = 6;
        } else {
                return;
        }

        /* allocate/initialize a new nfs_callback_socket */
        MALLOC(ncbsp, struct nfs_callback_socket *, sizeof(struct nfs_callback_socket), M_TEMP, M_WAITOK);
        if (!ncbsp) {
                log(LOG_ERR, "nfs callback accept: no memory for new socket\n");
                return;
        }
        bzero(ncbsp, sizeof(*ncbsp));
        ncbsp->ncbs_saddr.ss_len = (ip == 4) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6);
        nfs_rpc_record_state_init(&ncbsp->ncbs_rrs);

        /* accept a new socket */
        error = sock_accept(so, (struct sockaddr*)&ncbsp->ncbs_saddr,
            ncbsp->ncbs_saddr.ss_len, MSG_DONTWAIT,
            nfs4_cb_rcv, ncbsp, &newso);
        if (error) {
                log(LOG_INFO, "nfs callback accept: error %d accepting IPv%d socket\n", error, ip);
                FREE(ncbsp, M_TEMP);
                return;
        }

        /* set up the new socket */
        /* receive timeout shouldn't matter.  If timeout on send, we'll want to drop the socket */
        timeo.tv_usec = 0;
        timeo.tv_sec = 60;
        error = sock_setsockopt(newso, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback socket: error %d setting IPv%d socket rx timeout\n", error, ip);
        }
        error = sock_setsockopt(newso, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
        if (error) {
                log(LOG_INFO, "nfs callback socket: error %d setting IPv%d socket tx timeout\n", error, ip);
        }
        sock_setsockopt(newso, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
        sock_setsockopt(newso, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
        sock_setsockopt(newso, SOL_SOCKET, SO_NOADDRERR, &on, sizeof(on));
        sock_setsockopt(newso, SOL_SOCKET, SO_UPCALLCLOSEWAIT, &on, sizeof(on));

        ncbsp->ncbs_so = newso;
        microuptime(&now);
        ncbsp->ncbs_stamp = now.tv_sec;

        lck_mtx_lock(nfs_global_mutex);

        /* add it to the list */
        TAILQ_INSERT_HEAD(&nfs4_cb_socks, ncbsp, ncbs_link);

        /* verify it's from a host we have mounted */
        TAILQ_FOREACH(nmp, &nfs4_cb_mounts, nm_cblink) {
                /* check if socket's source address matches this mount's server address */
                if (!nmp->nm_saddr) {
                        continue;
                }
                if (nfs_sockaddr_cmp((struct sockaddr*)&ncbsp->ncbs_saddr, nmp->nm_saddr) == 0) {
                        break;
                }
        }
        if (!nmp) { /* we don't want this socket, mark it dead */
                ncbsp->ncbs_flags |= NCBSOCK_DEAD;
        }

        /* make sure the callback socket cleanup timer is running */
        /* (shorten the timer if we've got a socket we don't want) */
        if (!nfs4_callback_timer_on) {
                nfs4_callback_timer_on = 1;
                nfs_interval_timer_start(nfs4_callback_timer_call,
                    !nmp ? 500 : (NFS4_CB_TIMER_PERIOD * 1000));
        } else if (!nmp && (nfs4_callback_timer_on < 2)) {
                nfs4_callback_timer_on = 2;
                thread_call_cancel(nfs4_callback_timer_call);
                nfs_interval_timer_start(nfs4_callback_timer_call, 500);
        }

        lck_mtx_unlock(nfs_global_mutex);
}

/*
 * Receive mbufs from callback sockets into RPC records and process each record.
 * Detect connection has been closed and shut down.
 */
void
nfs4_cb_rcv(socket_t so, void *arg, __unused int waitflag)
{
        struct nfs_callback_socket *ncbsp = arg;
        struct timespec ts = { .tv_sec = 1, .tv_nsec = 0 };
        struct timeval now;
        mbuf_t m;
        int error = 0, recv = 1;

        lck_mtx_lock(nfs_global_mutex);
        while (ncbsp->ncbs_flags & NCBSOCK_UPCALL) {
                /* wait if upcall is already in progress */
                ncbsp->ncbs_flags |= NCBSOCK_UPCALLWANT;
                msleep(ncbsp, nfs_global_mutex, PSOCK, "cbupcall", &ts);
        }
        ncbsp->ncbs_flags |= NCBSOCK_UPCALL;
        lck_mtx_unlock(nfs_global_mutex);

        /* loop while we make error-free progress */
        while (!error && recv) {
                error = nfs_rpc_record_read(so, &ncbsp->ncbs_rrs, MSG_DONTWAIT, &recv, &m);
                if (m) { /* handle the request */
                        error = nfs4_cb_handler(ncbsp, m);
                }
        }

        /* note: no error and no data indicates server closed its end */
        if ((error != EWOULDBLOCK) && (error || !recv)) {
                /*
                 * Socket is either being closed or should be.
                 * We can't close the socket in the context of the upcall.
                 * So we mark it as dead and leave it for the cleanup timer to reap.
                 */
                ncbsp->ncbs_stamp = 0;
                ncbsp->ncbs_flags |= NCBSOCK_DEAD;
        } else {
                microuptime(&now);
                ncbsp->ncbs_stamp = now.tv_sec;
        }

        lck_mtx_lock(nfs_global_mutex);
        ncbsp->ncbs_flags &= ~NCBSOCK_UPCALL;
        lck_mtx_unlock(nfs_global_mutex);
        wakeup(ncbsp);
}

/*
 * Handle an NFS callback channel request.
 */
int
nfs4_cb_handler(struct nfs_callback_socket *ncbsp, mbuf_t mreq)
{
        socket_t so = ncbsp->ncbs_so;
        struct nfsm_chain nmreq, nmrep;
        mbuf_t mhead = NULL, mrest = NULL, m;
        struct msghdr msg;
        struct nfsmount *nmp;
        fhandle_t fh;
        nfsnode_t np;
        nfs_stateid stateid;
        uint32_t bitmap[NFS_ATTR_BITMAP_LEN], rbitmap[NFS_ATTR_BITMAP_LEN], bmlen, truncate, attrbytes;
        uint32_t val, xid, procnum, taglen, cbid, numops, op, status;
        uint32_t auth_type, auth_len;
        uint32_t numres, *pnumres;
        int error = 0, replen, len;
        size_t sentlen = 0;

        xid = numops = op = status = procnum = taglen = cbid = 0;

        nfsm_chain_dissect_init(error, &nmreq, mreq);
        nfsm_chain_get_32(error, &nmreq, xid);          // RPC XID
        nfsm_chain_get_32(error, &nmreq, val);          // RPC Call
        nfsm_assert(error, (val == RPC_CALL), EBADRPC);
        nfsm_chain_get_32(error, &nmreq, val);          // RPC Version
        nfsm_assert(error, (val == RPC_VER2), ERPCMISMATCH);
        nfsm_chain_get_32(error, &nmreq, val);          // RPC Program Number
        nfsm_assert(error, (val == NFS4_CALLBACK_PROG), EPROGUNAVAIL);
        nfsm_chain_get_32(error, &nmreq, val);          // NFS Callback Program Version Number
        nfsm_assert(error, (val == NFS4_CALLBACK_PROG_VERSION), EPROGMISMATCH);
        nfsm_chain_get_32(error, &nmreq, procnum);      // NFS Callback Procedure Number
        nfsm_assert(error, (procnum <= NFSPROC4_CB_COMPOUND), EPROCUNAVAIL);

        /* Handle authentication */
        /* XXX just ignore auth for now - handling kerberos may be tricky */
        nfsm_chain_get_32(error, &nmreq, auth_type);    // RPC Auth Flavor
        nfsm_chain_get_32(error, &nmreq, auth_len);     // RPC Auth Length
        nfsm_assert(error, (auth_len <= RPCAUTH_MAXSIZ), EBADRPC);
        if (!error && (auth_len > 0)) {
                nfsm_chain_adv(error, &nmreq, nfsm_rndup(auth_len));
        }
        nfsm_chain_adv(error, &nmreq, NFSX_UNSIGNED);   // verifier flavor (should be AUTH_NONE)
        nfsm_chain_get_32(error, &nmreq, auth_len);     // verifier length
        nfsm_assert(error, (auth_len <= RPCAUTH_MAXSIZ), EBADRPC);
        if (!error && (auth_len > 0)) {
                nfsm_chain_adv(error, &nmreq, nfsm_rndup(auth_len));
        }
        if (error) {
                status = error;
                error = 0;
                goto nfsmout;
        }

        switch (procnum) {
        case NFSPROC4_CB_NULL:
                status = NFSERR_RETVOID;
                break;
        case NFSPROC4_CB_COMPOUND:
                /* tag, minorversion, cb ident, numops, op array */
                nfsm_chain_get_32(error, &nmreq, taglen);       /* tag length */
                nfsm_assert(error, (val <= NFS4_OPAQUE_LIMIT), EBADRPC);

                /* start building the body of the response */
                nfsm_mbuf_get(error, &mrest, nfsm_rndup(taglen) + 5 * NFSX_UNSIGNED);
                nfsm_chain_init(&nmrep, mrest);

                /* copy tag from request to response */
                nfsm_chain_add_32(error, &nmrep, taglen);       /* tag length */
                for (len = (int)taglen; !error && (len > 0); len -= NFSX_UNSIGNED) {
                        nfsm_chain_get_32(error, &nmreq, val);
                        nfsm_chain_add_32(error, &nmrep, val);
                }

                /* insert number of results placeholder */
                numres = 0;
                nfsm_chain_add_32(error, &nmrep, numres);
                pnumres = (uint32_t*)(nmrep.nmc_ptr - NFSX_UNSIGNED);

                nfsm_chain_get_32(error, &nmreq, val);          /* minorversion */
                nfsm_assert(error, (val == 0), NFSERR_MINOR_VERS_MISMATCH);
                nfsm_chain_get_32(error, &nmreq, cbid);         /* callback ID */
                nfsm_chain_get_32(error, &nmreq, numops);       /* number of operations */
                if (error) {
                        if ((error == EBADRPC) || (error == NFSERR_MINOR_VERS_MISMATCH)) {
                                status = error;
                        } else if ((error == ENOBUFS) || (error == ENOMEM)) {
                                status = NFSERR_RESOURCE;
                        } else {
                                status = NFSERR_SERVERFAULT;
                        }
                        error = 0;
                        nfsm_chain_null(&nmrep);
                        goto nfsmout;
                }
                /* match the callback ID to a registered mount */
                lck_mtx_lock(nfs_global_mutex);
                TAILQ_FOREACH(nmp, &nfs4_cb_mounts, nm_cblink) {
                        if (nmp->nm_cbid != cbid) {
                                continue;
                        }
                        /* verify socket's source address matches this mount's server address */
                        if (!nmp->nm_saddr) {
                                continue;
                        }
                        if (nfs_sockaddr_cmp((struct sockaddr*)&ncbsp->ncbs_saddr, nmp->nm_saddr) == 0) {
                                break;
                        }
                }
                /* mark the NFS mount as busy */
                if (nmp) {
                        nmp->nm_cbrefs++;
                }
                lck_mtx_unlock(nfs_global_mutex);
                if (!nmp) {
                        /* if no mount match, just drop socket. */
                        error = EPERM;
                        nfsm_chain_null(&nmrep);
                        goto out;
                }

                /* process ops, adding results to mrest */
                while (numops > 0) {
                        numops--;
                        nfsm_chain_get_32(error, &nmreq, op);
                        if (error) {
                                break;
                        }
                        switch (op) {
                        case NFS_OP_CB_GETATTR:
                                // (FH, BITMAP) -> (STATUS, BITMAP, ATTRS)
                                np = NULL;
                                nfsm_chain_get_fh(error, &nmreq, NFS_VER4, &fh);
                                bmlen = NFS_ATTR_BITMAP_LEN;
                                nfsm_chain_get_bitmap(error, &nmreq, bitmap, bmlen);
                                if (error) {
                                        status = error;
                                        error = 0;
                                        numops = 0; /* don't process any more ops */
                                } else {
                                        /* find the node for the file handle */
                                        error = nfs_nget(nmp->nm_mountp, NULL, NULL, fh.fh_data, fh.fh_len, NULL, NULL, RPCAUTH_UNKNOWN, NG_NOCREATE, &np);
                                        if (error || !np) {
                                                status = NFSERR_BADHANDLE;
                                                error = 0;
                                                np = NULL;
                                                numops = 0; /* don't process any more ops */
                                        }
                                }
                                nfsm_chain_add_32(error, &nmrep, op);
                                nfsm_chain_add_32(error, &nmrep, status);
                                if (!error && (status == EBADRPC)) {
                                        error = status;
                                }
                                if (np) {
                                        /* only allow returning size, change, and mtime attrs */
                                        NFS_CLEAR_ATTRIBUTES(&rbitmap);
                                        attrbytes = 0;
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_CHANGE)) {
                                                NFS_BITMAP_SET(&rbitmap, NFS_FATTR_CHANGE);
                                                attrbytes += 2 * NFSX_UNSIGNED;
                                        }
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_SIZE)) {
                                                NFS_BITMAP_SET(&rbitmap, NFS_FATTR_SIZE);
                                                attrbytes += 2 * NFSX_UNSIGNED;
                                        }
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_TIME_MODIFY)) {
                                                NFS_BITMAP_SET(&rbitmap, NFS_FATTR_TIME_MODIFY);
                                                attrbytes += 3 * NFSX_UNSIGNED;
                                        }
                                        nfsm_chain_add_bitmap(error, &nmrep, rbitmap, NFS_ATTR_BITMAP_LEN);
                                        nfsm_chain_add_32(error, &nmrep, attrbytes);
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_CHANGE)) {
                                                nfsm_chain_add_64(error, &nmrep,
                                                    np->n_vattr.nva_change + ((np->n_flag & NMODIFIED) ? 1 : 0));
                                        }
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_SIZE)) {
                                                nfsm_chain_add_64(error, &nmrep, np->n_size);
                                        }
                                        if (NFS_BITMAP_ISSET(&bitmap, NFS_FATTR_TIME_MODIFY)) {
                                                nfsm_chain_add_64(error, &nmrep, np->n_vattr.nva_timesec[NFSTIME_MODIFY]);
                                                nfsm_chain_add_32(error, &nmrep, np->n_vattr.nva_timensec[NFSTIME_MODIFY]);
                                        }
                                        nfs_node_unlock(np);
                                        vnode_put(NFSTOV(np));
                                        np = NULL;
                                }
                                /*
                                 * If we hit an error building the reply, we can't easily back up.
                                 * So we'll just update the status and hope the server ignores the
                                 * extra garbage.
                                 */
                                break;
                        case NFS_OP_CB_RECALL:
                                // (STATEID, TRUNCATE, FH) -> (STATUS)
                                np = NULL;
                                nfsm_chain_get_stateid(error, &nmreq, &stateid);
                                nfsm_chain_get_32(error, &nmreq, truncate);
                                nfsm_chain_get_fh(error, &nmreq, NFS_VER4, &fh);
                                if (error) {
                                        status = error;
                                        error = 0;
                                        numops = 0; /* don't process any more ops */
                                } else {
                                        /* find the node for the file handle */
                                        error = nfs_nget(nmp->nm_mountp, NULL, NULL, fh.fh_data, fh.fh_len, NULL, NULL, RPCAUTH_UNKNOWN, NG_NOCREATE, &np);
                                        if (error || !np) {
                                                status = NFSERR_BADHANDLE;
                                                error = 0;
                                                np = NULL;
                                                numops = 0; /* don't process any more ops */
                                        } else if (!(np->n_openflags & N_DELEG_MASK) ||
                                            bcmp(&np->n_dstateid, &stateid, sizeof(stateid))) {
                                                /* delegation stateid state doesn't match */
                                                status = NFSERR_BAD_STATEID;
                                                numops = 0; /* don't process any more ops */
                                        }
                                        if (!status) { /* add node to recall queue, and wake socket thread */
                                                nfs4_delegation_return_enqueue(np);
                                        }
                                        if (np) {
                                                nfs_node_unlock(np);
                                                vnode_put(NFSTOV(np));
                                        }
                                }
                                nfsm_chain_add_32(error, &nmrep, op);
                                nfsm_chain_add_32(error, &nmrep, status);
                                if (!error && (status == EBADRPC)) {
                                        error = status;
                                }
                                break;
                        case NFS_OP_CB_ILLEGAL:
                        default:
                                nfsm_chain_add_32(error, &nmrep, NFS_OP_CB_ILLEGAL);
                                status = NFSERR_OP_ILLEGAL;
                                nfsm_chain_add_32(error, &nmrep, status);
                                numops = 0; /* don't process any more ops */
                                break;
                        }
                        numres++;
                }

                if (!status && error) {
                        if (error == EBADRPC) {
                                status = error;
                        } else if ((error == ENOBUFS) || (error == ENOMEM)) {
                                status = NFSERR_RESOURCE;
                        } else {
                                status = NFSERR_SERVERFAULT;
                        }
                        error = 0;
                }

                /* Now, set the numres field */
                *pnumres = txdr_unsigned(numres);
                nfsm_chain_build_done(error, &nmrep);
                nfsm_chain_null(&nmrep);

                /* drop the callback reference on the mount */
                lck_mtx_lock(nfs_global_mutex);
                nmp->nm_cbrefs--;
                if (!nmp->nm_cbid) {
                        wakeup(&nmp->nm_cbrefs);
                }
                lck_mtx_unlock(nfs_global_mutex);
                break;
        }

nfsmout:
        if (status == EBADRPC) {
                OSAddAtomic64(1, &nfsstats.rpcinvalid);
        }

        /* build reply header */
        error = mbuf_gethdr(MBUF_WAITOK, MBUF_TYPE_DATA, &mhead);
        nfsm_chain_init(&nmrep, mhead);
        nfsm_chain_add_32(error, &nmrep, 0); /* insert space for an RPC record mark */
        nfsm_chain_add_32(error, &nmrep, xid);
        nfsm_chain_add_32(error, &nmrep, RPC_REPLY);
        if ((status == ERPCMISMATCH) || (status & NFSERR_AUTHERR)) {
                nfsm_chain_add_32(error, &nmrep, RPC_MSGDENIED);
                if (status & NFSERR_AUTHERR) {
                        nfsm_chain_add_32(error, &nmrep, RPC_AUTHERR);
                        nfsm_chain_add_32(error, &nmrep, (status & ~NFSERR_AUTHERR));
                } else {
                        nfsm_chain_add_32(error, &nmrep, RPC_MISMATCH);
                        nfsm_chain_add_32(error, &nmrep, RPC_VER2);
                        nfsm_chain_add_32(error, &nmrep, RPC_VER2);
                }
        } else {
                /* reply status */
                nfsm_chain_add_32(error, &nmrep, RPC_MSGACCEPTED);
                /* XXX RPCAUTH_NULL verifier */
                nfsm_chain_add_32(error, &nmrep, RPCAUTH_NULL);
                nfsm_chain_add_32(error, &nmrep, 0);
                /* accepted status */
                switch (status) {
                case EPROGUNAVAIL:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROGUNAVAIL);
                        break;
                case EPROGMISMATCH:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROGMISMATCH);
                        nfsm_chain_add_32(error, &nmrep, NFS4_CALLBACK_PROG_VERSION);
                        nfsm_chain_add_32(error, &nmrep, NFS4_CALLBACK_PROG_VERSION);
                        break;
                case EPROCUNAVAIL:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROCUNAVAIL);
                        break;
                case EBADRPC:
                        nfsm_chain_add_32(error, &nmrep, RPC_GARBAGE);
                        break;
                default:
                        nfsm_chain_add_32(error, &nmrep, RPC_SUCCESS);
                        if (status != NFSERR_RETVOID) {
                                nfsm_chain_add_32(error, &nmrep, status);
                        }
                        break;
                }
        }
        nfsm_chain_build_done(error, &nmrep);
        if (error) {
                nfsm_chain_null(&nmrep);
                goto out;
        }
        error = mbuf_setnext(nmrep.nmc_mcur, mrest);
        if (error) {
                printf("nfs cb: mbuf_setnext failed %d\n", error);
                goto out;
        }
        mrest = NULL;
        /* Calculate the size of the reply */
        replen = 0;
        for (m = nmrep.nmc_mhead; m; m = mbuf_next(m)) {
                replen += mbuf_len(m);
        }
        mbuf_pkthdr_setlen(mhead, replen);
        error = mbuf_pkthdr_setrcvif(mhead, NULL);
        nfsm_chain_set_recmark(error, &nmrep, (replen - NFSX_UNSIGNED) | 0x80000000);
        nfsm_chain_null(&nmrep);

        /* send the reply */
        bzero(&msg, sizeof(msg));
        error = sock_sendmbuf(so, &msg, mhead, 0, &sentlen);
        mhead = NULL;
        if (!error && ((int)sentlen != replen)) {
                error = EWOULDBLOCK;
        }
        if (error == EWOULDBLOCK) { /* inability to send response is considered fatal */
                error = ETIMEDOUT;
        }
out:
        if (error) {
                nfsm_chain_cleanup(&nmrep);
        }
        if (mhead) {
                mbuf_freem(mhead);
        }
        if (mrest) {
                mbuf_freem(mrest);
        }
        if (mreq) {
                mbuf_freem(mreq);
        }
        return error;
}
#endif /* CONFIG_NFS4 */

/*
 * Initialize an nfs_rpc_record_state structure.
 */
void
nfs_rpc_record_state_init(struct nfs_rpc_record_state *nrrsp)
{
        bzero(nrrsp, sizeof(*nrrsp));
        nrrsp->nrrs_markerleft = sizeof(nrrsp->nrrs_fragleft);
}

/*
 * Clean up an nfs_rpc_record_state structure.
 */
void
nfs_rpc_record_state_cleanup(struct nfs_rpc_record_state *nrrsp)
{
        if (nrrsp->nrrs_m) {
                mbuf_freem(nrrsp->nrrs_m);
                nrrsp->nrrs_m = nrrsp->nrrs_mlast = NULL;
        }
}

/*
 * Read the next (marked) RPC record from the socket.
 *
 * *recvp returns if any data was received.
 * *mp returns the next complete RPC record
 */
int
nfs_rpc_record_read(socket_t so, struct nfs_rpc_record_state *nrrsp, int flags, int *recvp, mbuf_t *mp)
{
        struct iovec aio;
        struct msghdr msg;
        size_t rcvlen;
        int error = 0;
        mbuf_t m;

        *recvp = 0;
        *mp = NULL;

        /* read the TCP RPC record marker */
        while (!error && nrrsp->nrrs_markerleft) {
                aio.iov_base = ((char*)&nrrsp->nrrs_fragleft +
                    sizeof(nrrsp->nrrs_fragleft) - nrrsp->nrrs_markerleft);
                aio.iov_len = nrrsp->nrrs_markerleft;
                bzero(&msg, sizeof(msg));
                msg.msg_iov = &aio;
                msg.msg_iovlen = 1;
                error = sock_receive(so, &msg, flags, &rcvlen);
                if (error || !rcvlen) {
                        break;
                }
                *recvp = 1;
                nrrsp->nrrs_markerleft -= rcvlen;
                if (nrrsp->nrrs_markerleft) {
                        continue;
                }
                /* record marker complete */
                nrrsp->nrrs_fragleft = ntohl(nrrsp->nrrs_fragleft);
                if (nrrsp->nrrs_fragleft & 0x80000000) {
                        nrrsp->nrrs_lastfrag = 1;
                        nrrsp->nrrs_fragleft &= ~0x80000000;
                }
                nrrsp->nrrs_reclen += nrrsp->nrrs_fragleft;
                if (nrrsp->nrrs_reclen > NFS_MAXPACKET) {
                        /* This is SERIOUS! We are out of sync with the sender. */
                        log(LOG_ERR, "impossible RPC record length (%d) on callback", nrrsp->nrrs_reclen);
                        error = EFBIG;
                }
        }

        /* read the TCP RPC record fragment */
        while (!error && !nrrsp->nrrs_markerleft && nrrsp->nrrs_fragleft) {
                m = NULL;
                rcvlen = nrrsp->nrrs_fragleft;
                error = sock_receivembuf(so, NULL, &m, flags, &rcvlen);
                if (error || !rcvlen || !m) {
                        break;
                }
                *recvp = 1;
                /* append mbufs to list */
                nrrsp->nrrs_fragleft -= rcvlen;
                if (!nrrsp->nrrs_m) {
                        nrrsp->nrrs_m = m;
                } else {
                        error = mbuf_setnext(nrrsp->nrrs_mlast, m);
                        if (error) {
                                printf("nfs tcp rcv: mbuf_setnext failed %d\n", error);
                                mbuf_freem(m);
                                break;
                        }
                }
                while (mbuf_next(m)) {
                        m = mbuf_next(m);
                }
                nrrsp->nrrs_mlast = m;
        }

        /* done reading fragment? */
        if (!error && !nrrsp->nrrs_markerleft && !nrrsp->nrrs_fragleft) {
                /* reset socket fragment parsing state */
                nrrsp->nrrs_markerleft = sizeof(nrrsp->nrrs_fragleft);
                if (nrrsp->nrrs_lastfrag) {
                        /* RPC record complete */
                        *mp = nrrsp->nrrs_m;
                        /* reset socket record parsing state */
                        nrrsp->nrrs_reclen = 0;
                        nrrsp->nrrs_m = nrrsp->nrrs_mlast = NULL;
                        nrrsp->nrrs_lastfrag = 0;
                }
        }

        return error;
}



/*
 * The NFS client send routine.
 *
 * Send the given NFS request out the mount's socket.
 * Holds nfs_sndlock() for the duration of this call.
 *
 * - check for request termination (sigintr)
 * - wait for reconnect, if necessary
 * - UDP: check the congestion window
 * - make a copy of the request to send
 * - UDP: update the congestion window
 * - send the request
 *
 * If sent successfully, R_MUSTRESEND and R_RESENDERR are cleared.
 * rexmit count is also updated if this isn't the first send.
 *
 * If the send is not successful, make sure R_MUSTRESEND is set.
 * If this wasn't the first transmit, set R_RESENDERR.
 * Also, undo any UDP congestion window changes made.
 *
 * If the error appears to indicate that the socket should
 * be reconnected, mark the socket for reconnection.
 *
 * Only return errors when the request should be aborted.
 */
int
nfs_send(struct nfsreq *req, int wait)
{
        struct nfsmount *nmp;
        struct nfs_socket *nso;
        int error, error2, sotype, rexmit, slpflag = 0, needrecon;
        struct msghdr msg;
        struct sockaddr *sendnam;
        mbuf_t mreqcopy;
        size_t sentlen = 0;
        struct timespec ts = { .tv_sec = 2, .tv_nsec = 0 };

again:
        error = nfs_sndlock(req);
        if (error) {
                lck_mtx_lock(&req->r_mtx);
                req->r_error = error;
                req->r_flags &= ~R_SENDING;
                lck_mtx_unlock(&req->r_mtx);
                return error;
        }

        error = nfs_sigintr(req->r_nmp, req, NULL, 0);
        if (error) {
                nfs_sndunlock(req);
                lck_mtx_lock(&req->r_mtx);
                req->r_error = error;
                req->r_flags &= ~R_SENDING;
                lck_mtx_unlock(&req->r_mtx);
                return error;
        }
        nmp = req->r_nmp;
        sotype = nmp->nm_sotype;

        /*
         * If it's a setup RPC but we're not in SETUP... must need reconnect.
         * If it's a recovery RPC but the socket's not ready... must need reconnect.
         */
        if (((req->r_flags & R_SETUP) && !(nmp->nm_sockflags & NMSOCK_SETUP)) ||
            ((req->r_flags & R_RECOVER) && !(nmp->nm_sockflags & NMSOCK_READY))) {
                error = ETIMEDOUT;
                nfs_sndunlock(req);
                lck_mtx_lock(&req->r_mtx);
                req->r_error = error;
                req->r_flags &= ~R_SENDING;
                lck_mtx_unlock(&req->r_mtx);
                return error;
        }

        /* If the socket needs reconnection, do that now. */
        /* wait until socket is ready - unless this request is part of setup */
        lck_mtx_lock(&nmp->nm_lock);
        if (!(nmp->nm_sockflags & NMSOCK_READY) &&
            !((nmp->nm_sockflags & NMSOCK_SETUP) && (req->r_flags & R_SETUP))) {
                if (NMFLAG(nmp, INTR) && !(req->r_flags & R_NOINTR)) {
                        slpflag |= PCATCH;
                }
                lck_mtx_unlock(&nmp->nm_lock);
                nfs_sndunlock(req);
                if (!wait) {
                        lck_mtx_lock(&req->r_mtx);
                        req->r_flags &= ~R_SENDING;
                        req->r_flags |= R_MUSTRESEND;
                        req->r_rtt = 0;
                        lck_mtx_unlock(&req->r_mtx);
                        return 0;
                }
                NFS_SOCK_DBG("nfs_send: 0x%llx wait reconnect\n", req->r_xid);
                lck_mtx_lock(&req->r_mtx);
                req->r_flags &= ~R_MUSTRESEND;
                req->r_rtt = 0;
                lck_mtx_unlock(&req->r_mtx);
                lck_mtx_lock(&nmp->nm_lock);
                while (!(nmp->nm_sockflags & NMSOCK_READY)) {
                        /* don't bother waiting if the socket thread won't be reconnecting it */
                        if (nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD)) {
                                error = EIO;
                                break;
                        }
                        if ((NMFLAG(nmp, SOFT) || (req->r_flags & R_SOFT)) && (nmp->nm_reconnect_start > 0)) {
                                struct timeval now;
                                microuptime(&now);
                                if ((now.tv_sec - nmp->nm_reconnect_start) >= 8) {
                                        /* soft mount in reconnect for a while... terminate ASAP */
                                        OSAddAtomic64(1, &nfsstats.rpctimeouts);
                                        req->r_flags |= R_SOFTTERM;
                                        req->r_error = error = ETIMEDOUT;
                                        break;
                                }
                        }
                        /* make sure socket thread is running, then wait */
                        nfs_mount_sock_thread_wake(nmp);
                        if ((error = nfs_sigintr(req->r_nmp, req, req->r_thread, 1))) {
                                break;
                        }
                        msleep(req, &nmp->nm_lock, slpflag | PSOCK, "nfsconnectwait", &ts);
                        slpflag = 0;
                }
                lck_mtx_unlock(&nmp->nm_lock);
                if (error) {
                        lck_mtx_lock(&req->r_mtx);
                        req->r_error = error;
                        req->r_flags &= ~R_SENDING;
                        lck_mtx_unlock(&req->r_mtx);
                        return error;
                }
                goto again;
        }
        nso = nmp->nm_nso;
        /* note that we're using the mount's socket to do the send */
        nmp->nm_state |= NFSSTA_SENDING;  /* will be cleared by nfs_sndunlock() */
        lck_mtx_unlock(&nmp->nm_lock);
        if (!nso) {
                nfs_sndunlock(req);
                lck_mtx_lock(&req->r_mtx);
                req->r_flags &= ~R_SENDING;
                req->r_flags |= R_MUSTRESEND;
                req->r_rtt = 0;
                lck_mtx_unlock(&req->r_mtx);
                return 0;
        }

        lck_mtx_lock(&req->r_mtx);
        rexmit = (req->r_flags & R_SENT);

        if (sotype == SOCK_DGRAM) {
                lck_mtx_lock(&nmp->nm_lock);
                if (!(req->r_flags & R_CWND) && (nmp->nm_sent >= nmp->nm_cwnd)) {
                        /* if we can't send this out yet, wait on the cwnd queue */
                        slpflag = (NMFLAG(nmp, INTR) && req->r_thread) ? PCATCH : 0;
                        lck_mtx_unlock(&nmp->nm_lock);
                        nfs_sndunlock(req);
                        req->r_flags &= ~R_SENDING;
                        req->r_flags |= R_MUSTRESEND;
                        lck_mtx_unlock(&req->r_mtx);
                        if (!wait) {
                                req->r_rtt = 0;
                                return 0;
                        }
                        lck_mtx_lock(&nmp->nm_lock);
                        while (nmp->nm_sent >= nmp->nm_cwnd) {
                                if ((error = nfs_sigintr(req->r_nmp, req, req->r_thread, 1))) {
                                        break;
                                }
                                TAILQ_INSERT_TAIL(&nmp->nm_cwndq, req, r_cchain);
                                msleep(req, &nmp->nm_lock, slpflag | (PZERO - 1), "nfswaitcwnd", &ts);
                                slpflag = 0;
                                if ((req->r_cchain.tqe_next != NFSREQNOLIST)) {
                                        TAILQ_REMOVE(&nmp->nm_cwndq, req, r_cchain);
                                        req->r_cchain.tqe_next = NFSREQNOLIST;
                                }
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                        goto again;
                }
                /*
                 * We update these *before* the send to avoid racing
                 * against others who may be looking to send requests.
                 */
                if (!rexmit) {
                        /* first transmit */
                        req->r_flags |= R_CWND;
                        nmp->nm_sent += NFS_CWNDSCALE;
                } else {
                        /*
                         * When retransmitting, turn timing off
                         * and divide congestion window by 2.
                         */
                        req->r_flags &= ~R_TIMING;
                        nmp->nm_cwnd >>= 1;
                        if (nmp->nm_cwnd < NFS_CWNDSCALE) {
                                nmp->nm_cwnd = NFS_CWNDSCALE;
                        }
                }
                lck_mtx_unlock(&nmp->nm_lock);
        }

        req->r_flags &= ~R_MUSTRESEND;
        lck_mtx_unlock(&req->r_mtx);

        error = mbuf_copym(req->r_mhead, 0, MBUF_COPYALL,
            wait ? MBUF_WAITOK : MBUF_DONTWAIT, &mreqcopy);
        if (error) {
                if (wait) {
                        log(LOG_INFO, "nfs_send: mbuf copy failed %d\n", error);
                }
                nfs_sndunlock(req);
                lck_mtx_lock(&req->r_mtx);
                req->r_flags &= ~R_SENDING;
                req->r_flags |= R_MUSTRESEND;
                req->r_rtt = 0;
                lck_mtx_unlock(&req->r_mtx);
                return 0;
        }

        bzero(&msg, sizeof(msg));
        if ((sotype != SOCK_STREAM) && !sock_isconnected(nso->nso_so) && ((sendnam = nmp->nm_saddr))) {
                msg.msg_name = (caddr_t)sendnam;
                msg.msg_namelen = sendnam->sa_len;
        }
        NFS_SOCK_DUMP_MBUF("Sending mbuf\n", mreqcopy);
        error = sock_sendmbuf(nso->nso_so, &msg, mreqcopy, 0, &sentlen);
        if (error || (sentlen != req->r_mreqlen)) {
                NFS_SOCK_DBG("nfs_send: 0x%llx sent %d/%d error %d\n",
                    req->r_xid, (int)sentlen, (int)req->r_mreqlen, error);
        }

        if (!error && (sentlen != req->r_mreqlen)) {
                error = EWOULDBLOCK;
        }
        needrecon = ((sotype == SOCK_STREAM) && sentlen && (sentlen != req->r_mreqlen));

        lck_mtx_lock(&req->r_mtx);
        req->r_flags &= ~R_SENDING;
        req->r_rtt = 0;
        if (rexmit && (++req->r_rexmit > NFS_MAXREXMIT)) {
                req->r_rexmit = NFS_MAXREXMIT;
        }

        if (!error) {
                /* SUCCESS */
                req->r_flags &= ~R_RESENDERR;
                if (rexmit) {
                        OSAddAtomic64(1, &nfsstats.rpcretries);
                }
                req->r_flags |= R_SENT;
                if (req->r_flags & R_WAITSENT) {
                        req->r_flags &= ~R_WAITSENT;
                        wakeup(req);
                }
                nfs_sndunlock(req);
                lck_mtx_unlock(&req->r_mtx);
                return 0;
        }

        /* send failed */
        req->r_flags |= R_MUSTRESEND;
        if (rexmit) {
                req->r_flags |= R_RESENDERR;
        }
        if ((error == EINTR) || (error == ERESTART)) {
                req->r_error = error;
        }
        lck_mtx_unlock(&req->r_mtx);

        if (sotype == SOCK_DGRAM) {
                /*
                 * Note: even though a first send may fail, we consider
                 * the request sent for congestion window purposes.
                 * So we don't need to undo any of the changes made above.
                 */
                /*
                 * Socket errors ignored for connectionless sockets??
                 * For now, ignore them all
                 */
                if ((error != EINTR) && (error != ERESTART) &&
                    (error != EWOULDBLOCK) && (error != EIO) && (nso == nmp->nm_nso)) {
                        int clearerror = 0, optlen = sizeof(clearerror);
                        sock_getsockopt(nso->nso_so, SOL_SOCKET, SO_ERROR, &clearerror, &optlen);
#ifdef NFS_SOCKET_DEBUGGING
                        if (clearerror) {
                                NFS_SOCK_DBG("nfs_send: ignoring UDP socket error %d so %d\n",
                                    error, clearerror);
                        }
#endif
                }
        }

        /* check if it appears we should reconnect the socket */
        switch (error) {
        case EWOULDBLOCK:
                /* if send timed out, reconnect if on TCP */
                if (sotype != SOCK_STREAM) {
                        break;
                }
        case EPIPE:
        case EADDRNOTAVAIL:
        case ENETDOWN:
        case ENETUNREACH:
        case ENETRESET:
        case ECONNABORTED:
        case ECONNRESET:
        case ENOTCONN:
        case ESHUTDOWN:
        case ECONNREFUSED:
        case EHOSTDOWN:
        case EHOSTUNREACH:
                /* case ECANCELED??? */
                needrecon = 1;
                break;
        }
        if (needrecon && (nso == nmp->nm_nso)) { /* mark socket as needing reconnect */
                NFS_SOCK_DBG("nfs_send: 0x%llx need reconnect %d\n", req->r_xid, error);
                nfs_need_reconnect(nmp);
        }

        nfs_sndunlock(req);

        if (nfs_is_dead(error, nmp)) {
                error = EIO;
        }

        /*
         * Don't log some errors:
         * EPIPE errors may be common with servers that drop idle connections.
         * EADDRNOTAVAIL may occur on network transitions.
         * ENOTCONN may occur under some network conditions.
         */
        if ((error == EPIPE) || (error == EADDRNOTAVAIL) || (error == ENOTCONN)) {
                error = 0;
        }
        if (error && (error != EINTR) && (error != ERESTART)) {
                log(LOG_INFO, "nfs send error %d for server %s\n", error,
                    !req->r_nmp ? "<unmounted>" :
                    vfs_statfs(req->r_nmp->nm_mountp)->f_mntfromname);
        }

        /* prefer request termination error over other errors */
        error2 = nfs_sigintr(req->r_nmp, req, req->r_thread, 0);
        if (error2) {
                error = error2;
        }

        /* only allow the following errors to be returned */
        if ((error != EINTR) && (error != ERESTART) && (error != EIO) &&
            (error != ENXIO) && (error != ETIMEDOUT)) {
                /*
                 * We got some error we don't know what do do with,
                 * i.e., we're not reconnecting, we map it to
                 * EIO. Presumably our send failed and we better tell
                 * the caller so they don't wait for a reply that is
                 * never going to come.  If we are reconnecting we
                 * return 0 and the request will be resent.
                 */
                error = needrecon ? 0 : EIO;
        }
        return error;
}

/*
 * NFS client socket upcalls
 *
 * Pull RPC replies out of an NFS mount's socket and match them
 * up with the pending request.
 *
 * The datagram code is simple because we always get whole
 * messages out of the socket.
 *
 * The stream code is more involved because we have to parse
 * the RPC records out of the stream.
 */

/* NFS client UDP socket upcall */
void
nfs_udp_rcv(socket_t so, void *arg, __unused int waitflag)
{
        struct nfsmount *nmp = arg;
        struct nfs_socket *nso = nmp->nm_nso;
        size_t rcvlen;
        mbuf_t m;
        int error = 0;

        if (nmp->nm_sockflags & NMSOCK_CONNECTING) {
                return;
        }

        do {
                /* make sure we're on the current socket */
                if (!nso || (nso->nso_so != so)) {
                        return;
                }

                m = NULL;
                rcvlen = 1000000;
                error = sock_receivembuf(so, NULL, &m, MSG_DONTWAIT, &rcvlen);
                if (m) {
                        nfs_request_match_reply(nmp, m);
                }
        } while (m && !error);

        if (error && (error != EWOULDBLOCK)) {
                /* problems with the socket... mark for reconnection */
                NFS_SOCK_DBG("nfs_udp_rcv: need reconnect %d\n", error);
                nfs_need_reconnect(nmp);
        }
}

/* NFS client TCP socket upcall */
void
nfs_tcp_rcv(socket_t so, void *arg, __unused int waitflag)
{
        struct nfsmount *nmp = arg;
        struct nfs_socket *nso = nmp->nm_nso;
        struct nfs_rpc_record_state nrrs;
        mbuf_t m;
        int error = 0;
        int recv = 1;
        int wup = 0;

        if (nmp->nm_sockflags & NMSOCK_CONNECTING) {
                return;
        }

        /* make sure we're on the current socket */
        lck_mtx_lock(&nmp->nm_lock);
        nso = nmp->nm_nso;
        if (!nso || (nso->nso_so != so) || (nmp->nm_sockflags & (NMSOCK_DISCONNECTING))) {
                lck_mtx_unlock(&nmp->nm_lock);
                return;
        }
        lck_mtx_unlock(&nmp->nm_lock);

        /* make sure this upcall should be trying to do work */
        lck_mtx_lock(&nso->nso_lock);
        if (nso->nso_flags & (NSO_UPCALL | NSO_DISCONNECTING | NSO_DEAD)) {
                lck_mtx_unlock(&nso->nso_lock);
                return;
        }
        nso->nso_flags |= NSO_UPCALL;
        nrrs = nso->nso_rrs;
        lck_mtx_unlock(&nso->nso_lock);

        /* loop while we make error-free progress */
        while (!error && recv) {
                error = nfs_rpc_record_read(so, &nrrs, MSG_DONTWAIT, &recv, &m);
                if (m) { /* match completed response with request */
                        nfs_request_match_reply(nmp, m);
                }
        }

        /* Update the sockets's rpc parsing state */
        lck_mtx_lock(&nso->nso_lock);
        nso->nso_rrs = nrrs;
        if (nso->nso_flags & NSO_DISCONNECTING) {
                wup = 1;
        }
        nso->nso_flags &= ~NSO_UPCALL;
        lck_mtx_unlock(&nso->nso_lock);
        if (wup) {
                wakeup(&nso->nso_flags);
        }

#ifdef NFS_SOCKET_DEBUGGING
        if (!recv && (error != EWOULDBLOCK)) {
                NFS_SOCK_DBG("nfs_tcp_rcv: got nothing, error %d, got FIN?\n", error);
        }
#endif
        /* note: no error and no data indicates server closed its end */
        if ((error != EWOULDBLOCK) && (error || !recv)) {
                /* problems with the socket... mark for reconnection */
                NFS_SOCK_DBG("nfs_tcp_rcv: need reconnect %d\n", error);
                nfs_need_reconnect(nmp);
        }
}

/*
 * "poke" a socket to try to provoke any pending errors
 */
void
nfs_sock_poke(struct nfsmount *nmp)
{
        struct iovec aio;
        struct msghdr msg;
        size_t len;
        int error = 0;
        int dummy;

        lck_mtx_lock(&nmp->nm_lock);
        if ((nmp->nm_sockflags & NMSOCK_UNMOUNT) ||
            !(nmp->nm_sockflags & NMSOCK_READY) || !nmp->nm_nso || !nmp->nm_nso->nso_so) {
                /* Nothing to poke */
                nmp->nm_sockflags &= ~NMSOCK_POKE;
                wakeup(&nmp->nm_sockflags);
                lck_mtx_unlock(&nmp->nm_lock);
                return;
        }
        lck_mtx_unlock(&nmp->nm_lock);
        aio.iov_base = &dummy;
        aio.iov_len = 0;
        len = 0;
        bzero(&msg, sizeof(msg));
        msg.msg_iov = &aio;
        msg.msg_iovlen = 1;
        error = sock_send(nmp->nm_nso->nso_so, &msg, MSG_DONTWAIT, &len);
        NFS_SOCK_DBG("nfs_sock_poke: error %d\n", error);
        lck_mtx_lock(&nmp->nm_lock);
        nmp->nm_sockflags &= ~NMSOCK_POKE;
        wakeup(&nmp->nm_sockflags);
        lck_mtx_unlock(&nmp->nm_lock);
        nfs_is_dead(error, nmp);
}

/*
 * Match an RPC reply with the corresponding request
 */
void
nfs_request_match_reply(struct nfsmount *nmp, mbuf_t mrep)
{
        struct nfsreq *req;
        struct nfsm_chain nmrep;
        u_int32_t reply = 0, rxid = 0;
        int error = 0, asyncioq, t1;

        /* Get the xid and check that it is an rpc reply */
        nfsm_chain_dissect_init(error, &nmrep, mrep);
        nfsm_chain_get_32(error, &nmrep, rxid);
        nfsm_chain_get_32(error, &nmrep, reply);
        if (error || (reply != RPC_REPLY)) {
                OSAddAtomic64(1, &nfsstats.rpcinvalid);
                mbuf_freem(mrep);
                return;
        }

        /*
         * Loop through the request list to match up the reply
         * Iff no match, just drop it.
         */
        lck_mtx_lock(nfs_request_mutex);
        TAILQ_FOREACH(req, &nfs_reqq, r_chain) {
                if (req->r_nmrep.nmc_mhead || (rxid != R_XID32(req->r_xid))) {
                        continue;
                }
                /* looks like we have it, grab lock and double check */
                lck_mtx_lock(&req->r_mtx);
                if (req->r_nmrep.nmc_mhead || (rxid != R_XID32(req->r_xid))) {
                        lck_mtx_unlock(&req->r_mtx);
                        continue;
                }
                /* Found it.. */
                req->r_nmrep = nmrep;
                lck_mtx_lock(&nmp->nm_lock);
                if (nmp->nm_sotype == SOCK_DGRAM) {
                        /*
                         * Update congestion window.
                         * Do the additive increase of one rpc/rtt.
                         */
                        FSDBG(530, R_XID32(req->r_xid), req, nmp->nm_sent, nmp->nm_cwnd);
                        if (nmp->nm_cwnd <= nmp->nm_sent) {
                                nmp->nm_cwnd +=
                                    ((NFS_CWNDSCALE * NFS_CWNDSCALE) +
                                    (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
                                if (nmp->nm_cwnd > NFS_MAXCWND) {
                                        nmp->nm_cwnd = NFS_MAXCWND;
                                }
                        }
                        if (req->r_flags & R_CWND) {
                                nmp->nm_sent -= NFS_CWNDSCALE;
                                req->r_flags &= ~R_CWND;
                        }
                        if ((nmp->nm_sent < nmp->nm_cwnd) && !TAILQ_EMPTY(&nmp->nm_cwndq)) {
                                /* congestion window is open, poke the cwnd queue */
                                struct nfsreq *req2 = TAILQ_FIRST(&nmp->nm_cwndq);
                                TAILQ_REMOVE(&nmp->nm_cwndq, req2, r_cchain);
                                req2->r_cchain.tqe_next = NFSREQNOLIST;
                                wakeup(req2);
                        }
                }
                /*
                 * Update rtt using a gain of 0.125 on the mean
                 * and a gain of 0.25 on the deviation.
                 */
                if (req->r_flags & R_TIMING) {
                        /*
                         * Since the timer resolution of
                         * NFS_HZ is so course, it can often
                         * result in r_rtt == 0. Since
                         * r_rtt == N means that the actual
                         * rtt is between N+dt and N+2-dt ticks,
                         * add 1.
                         */
                        if (proct[req->r_procnum] == 0) {
                                panic("nfs_request_match_reply: proct[%d] is zero", req->r_procnum);
                        }
                        t1 = req->r_rtt + 1;
                        t1 -= (NFS_SRTT(req) >> 3);
                        NFS_SRTT(req) += t1;
                        if (t1 < 0) {
                                t1 = -t1;
                        }
                        t1 -= (NFS_SDRTT(req) >> 2);
                        NFS_SDRTT(req) += t1;
                }
                nmp->nm_timeouts = 0;
                lck_mtx_unlock(&nmp->nm_lock);
                /* signal anyone waiting on this request */
                wakeup(req);
                asyncioq = (req->r_callback.rcb_func != NULL);
#if CONFIG_NFS_GSS
                if (nfs_request_using_gss(req)) {
                        nfs_gss_clnt_rpcdone(req);
                }
#endif /* CONFIG_NFS_GSS */
                lck_mtx_unlock(&req->r_mtx);
                lck_mtx_unlock(nfs_request_mutex);
                /* if it's an async RPC with a callback, queue it up */
                if (asyncioq) {
                        nfs_asyncio_finish(req);
                }
                break;
        }

        if (!req) {
                /* not matched to a request, so drop it. */
                lck_mtx_unlock(nfs_request_mutex);
                OSAddAtomic64(1, &nfsstats.rpcunexpected);
                mbuf_freem(mrep);
        }
}

/*
 * Wait for the reply for a given request...
 * ...potentially resending the request if necessary.
 */
int
nfs_wait_reply(struct nfsreq *req)
{
        struct timespec ts = { .tv_sec = 2, .tv_nsec = 0 };
        int error = 0, slpflag, first = 1;

        if (req->r_nmp && NMFLAG(req->r_nmp, INTR) && req->r_thread && !(req->r_flags & R_NOINTR)) {
                slpflag = PCATCH;
        } else {
                slpflag = 0;
        }

        lck_mtx_lock(&req->r_mtx);
        while (!req->r_nmrep.nmc_mhead) {
                if ((error = nfs_sigintr(req->r_nmp, req, first ? NULL : req->r_thread, 0))) {
                        break;
                }
                if (((error = req->r_error)) || req->r_nmrep.nmc_mhead) {
                        break;
                }
                /* check if we need to resend */
                if (req->r_flags & R_MUSTRESEND) {
                        NFS_SOCK_DBG("nfs wait resend: p %d x 0x%llx f 0x%x rtt %d\n",
                            req->r_procnum, req->r_xid, req->r_flags, req->r_rtt);
                        req->r_flags |= R_SENDING;
                        lck_mtx_unlock(&req->r_mtx);
                        if (nfs_request_using_gss(req)) {
                                /*
                                 * It's an RPCSEC_GSS request.
                                 * Can't just resend the original request
                                 * without bumping the cred sequence number.
                                 * Go back and re-build the request.
                                 */
                                lck_mtx_lock(&req->r_mtx);
                                req->r_flags &= ~R_SENDING;
                                lck_mtx_unlock(&req->r_mtx);
                                return EAGAIN;
                        }
                        error = nfs_send(req, 1);
                        lck_mtx_lock(&req->r_mtx);
                        NFS_SOCK_DBG("nfs wait resend: p %d x 0x%llx f 0x%x rtt %d err %d\n",
                            req->r_procnum, req->r_xid, req->r_flags, req->r_rtt, error);
                        if (error) {
                                break;
                        }
                        if (((error = req->r_error)) || req->r_nmrep.nmc_mhead) {
                                break;
                        }
                }
                /* need to poll if we're P_NOREMOTEHANG */
                if (nfs_noremotehang(req->r_thread)) {
                        ts.tv_sec = 1;
                }
                msleep(req, &req->r_mtx, slpflag | (PZERO - 1), "nfswaitreply", &ts);
                first = slpflag = 0;
        }
        lck_mtx_unlock(&req->r_mtx);

        return error;
}

/*
 * An NFS request goes something like this:
 * (nb: always frees up mreq mbuf list)
 * nfs_request_create()
 *      - allocates a request struct if one is not provided
 *      - initial fill-in of the request struct
 * nfs_request_add_header()
 *      - add the RPC header
 * nfs_request_send()
 *      - link it into list
 *      - call nfs_send() for first transmit
 * nfs_request_wait()
 *      - call nfs_wait_reply() to wait for the reply
 * nfs_request_finish()
 *      - break down rpc header and return with error or nfs reply
 *        pointed to by nmrep.
 * nfs_request_rele()
 * nfs_request_destroy()
 *      - clean up the request struct
 *      - free the request struct if it was allocated by nfs_request_create()
 */

/*
 * Set up an NFS request struct (allocating if no request passed in).
 */
int
nfs_request_create(
        nfsnode_t np,
        mount_t mp,     /* used only if !np */
        struct nfsm_chain *nmrest,
        int procnum,
        thread_t thd,
        kauth_cred_t cred,
        struct nfsreq **reqp)
{
        struct nfsreq *req, *newreq = NULL;
        struct nfsmount *nmp;

        req = *reqp;
        if (!req) {
                /* allocate a new NFS request structure */
                MALLOC_ZONE(newreq, struct nfsreq*, sizeof(*newreq), M_NFSREQ, M_WAITOK);
                if (!newreq) {
                        mbuf_freem(nmrest->nmc_mhead);
                        nmrest->nmc_mhead = NULL;
                        return ENOMEM;
                }
                req = newreq;
        }

        bzero(req, sizeof(*req));
        if (req == newreq) {
                req->r_flags = R_ALLOCATED;
        }

        nmp = VFSTONFS(np ? NFSTOMP(np) : mp);
        if (nfs_mount_gone(nmp)) {
                if (newreq) {
                        FREE_ZONE(newreq, sizeof(*newreq), M_NFSREQ);
                }
                return ENXIO;
        }
        lck_mtx_lock(&nmp->nm_lock);
        if ((nmp->nm_state & (NFSSTA_FORCE | NFSSTA_DEAD)) &&
            (nmp->nm_state & NFSSTA_TIMEO)) {
                lck_mtx_unlock(&nmp->nm_lock);
                mbuf_freem(nmrest->nmc_mhead);
                nmrest->nmc_mhead = NULL;
                if (newreq) {
                        FREE_ZONE(newreq, sizeof(*newreq), M_NFSREQ);
                }
                return ENXIO;
        }

        if ((nmp->nm_vers != NFS_VER4) && (procnum >= 0) && (procnum < NFS_NPROCS)) {
                OSAddAtomic64(1, &nfsstats.rpccnt[procnum]);
        }
        if ((nmp->nm_vers == NFS_VER4) && (procnum != NFSPROC4_COMPOUND) && (procnum != NFSPROC4_NULL)) {
                panic("nfs_request: invalid NFSv4 RPC request %d\n", procnum);
        }

        lck_mtx_init(&req->r_mtx, nfs_request_grp, LCK_ATTR_NULL);
        req->r_nmp = nmp;
        nmp->nm_ref++;
        req->r_np = np;
        req->r_thread = thd;
        if (!thd) {
                req->r_flags |= R_NOINTR;
        }
        if (IS_VALID_CRED(cred)) {
                kauth_cred_ref(cred);
                req->r_cred = cred;
        }
        req->r_procnum = procnum;
        if (proct[procnum] > 0) {
                req->r_flags |= R_TIMING;
        }
        req->r_nmrep.nmc_mhead = NULL;
        SLIST_INIT(&req->r_gss_seqlist);
        req->r_achain.tqe_next = NFSREQNOLIST;
        req->r_rchain.tqe_next = NFSREQNOLIST;
        req->r_cchain.tqe_next = NFSREQNOLIST;

        /* set auth flavor to use for request */
        if (!req->r_cred) {
                req->r_auth = RPCAUTH_NONE;
        } else if (req->r_np && (req->r_np->n_auth != RPCAUTH_INVALID)) {
                req->r_auth = req->r_np->n_auth;
        } else {
                req->r_auth = nmp->nm_auth;
        }

        lck_mtx_unlock(&nmp->nm_lock);

        /* move the request mbuf chain to the nfsreq */
        req->r_mrest = nmrest->nmc_mhead;
        nmrest->nmc_mhead = NULL;

        req->r_flags |= R_INITTED;
        req->r_refs = 1;
        if (newreq) {
                *reqp = req;
        }
        return 0;
}

/*
 * Clean up and free an NFS request structure.
 */
void
nfs_request_destroy(struct nfsreq *req)
{
        struct nfsmount *nmp;
        int clearjbtimeo = 0;

#if CONFIG_NFS_GSS
        struct gss_seq *gsp, *ngsp;
#endif

        if (!req || !(req->r_flags & R_INITTED)) {
                return;
        }
        nmp  = req->r_nmp;
        req->r_flags &= ~R_INITTED;
        if (req->r_lflags & RL_QUEUED) {
                nfs_reqdequeue(req);
        }

        if (req->r_achain.tqe_next != NFSREQNOLIST) {
                /*
                 * Still on an async I/O queue?
                 * %%% But which one, we may be on a local iod.
                 */
                lck_mtx_lock(nfsiod_mutex);
                if (nmp && req->r_achain.tqe_next != NFSREQNOLIST) {
                        TAILQ_REMOVE(&nmp->nm_iodq, req, r_achain);
                        req->r_achain.tqe_next = NFSREQNOLIST;
                }
                lck_mtx_unlock(nfsiod_mutex);
        }

        lck_mtx_lock(&req->r_mtx);
        if (nmp) {
                lck_mtx_lock(&nmp->nm_lock);
                if (req->r_flags & R_CWND) {
                        /* Decrement the outstanding request count.  */
                        req->r_flags &= ~R_CWND;
                        nmp->nm_sent -= NFS_CWNDSCALE;
                        if ((nmp->nm_sent < nmp->nm_cwnd) && !TAILQ_EMPTY(&nmp->nm_cwndq)) {
                                /* congestion window is open, poke the cwnd queue */
                                struct nfsreq *req2 = TAILQ_FIRST(&nmp->nm_cwndq);
                                TAILQ_REMOVE(&nmp->nm_cwndq, req2, r_cchain);
                                req2->r_cchain.tqe_next = NFSREQNOLIST;
                                wakeup(req2);
                        }
                }
                assert((req->r_flags & R_RESENDQ) == 0);
                /* XXX should we just remove this conditional, we should have a reference if we're resending */
                if (req->r_rchain.tqe_next != NFSREQNOLIST) {
                        TAILQ_REMOVE(&nmp->nm_resendq, req, r_rchain);
                        req->r_rchain.tqe_next = NFSREQNOLIST;
                        if (req->r_flags & R_RESENDQ) {
                                req->r_flags &= ~R_RESENDQ;
                        }
                }
                if (req->r_cchain.tqe_next != NFSREQNOLIST) {
                        TAILQ_REMOVE(&nmp->nm_cwndq, req, r_cchain);
                        req->r_cchain.tqe_next = NFSREQNOLIST;
                }
                if (req->r_flags & R_JBTPRINTFMSG) {
                        req->r_flags &= ~R_JBTPRINTFMSG;
                        nmp->nm_jbreqs--;
                        clearjbtimeo = (nmp->nm_jbreqs == 0) ? NFSSTA_JUKEBOXTIMEO : 0;
                }
                lck_mtx_unlock(&nmp->nm_lock);
        }
        lck_mtx_unlock(&req->r_mtx);

        if (clearjbtimeo) {
                nfs_up(nmp, req->r_thread, clearjbtimeo, NULL);
        }
        if (req->r_mhead) {
                mbuf_freem(req->r_mhead);
        } else if (req->r_mrest) {
                mbuf_freem(req->r_mrest);
        }
        if (req->r_nmrep.nmc_mhead) {
                mbuf_freem(req->r_nmrep.nmc_mhead);
        }
        if (IS_VALID_CRED(req->r_cred)) {
                kauth_cred_unref(&req->r_cred);
        }
#if CONFIG_NFS_GSS
        if (nfs_request_using_gss(req)) {
                nfs_gss_clnt_rpcdone(req);
        }
        SLIST_FOREACH_SAFE(gsp, &req->r_gss_seqlist, gss_seqnext, ngsp)
        FREE(gsp, M_TEMP);
        if (req->r_gss_ctx) {
                nfs_gss_clnt_ctx_unref(req);
        }
#endif /* CONFIG_NFS_GSS */
        if (req->r_wrongsec) {
                FREE(req->r_wrongsec, M_TEMP);
        }
        if (nmp) {
                nfs_mount_rele(nmp);
        }
        lck_mtx_destroy(&req->r_mtx, nfs_request_grp);
        if (req->r_flags & R_ALLOCATED) {
                FREE_ZONE(req, sizeof(*req), M_NFSREQ);
        }
}

void
nfs_request_ref(struct nfsreq *req, int locked)
{
        if (!locked) {
                lck_mtx_lock(&req->r_mtx);
        }
        if (req->r_refs <= 0) {
                panic("nfsreq reference error");
        }
        req->r_refs++;
        if (!locked) {
                lck_mtx_unlock(&req->r_mtx);
        }
}

void
nfs_request_rele(struct nfsreq *req)
{
        int destroy;

        lck_mtx_lock(&req->r_mtx);
        if (req->r_refs <= 0) {
                panic("nfsreq reference underflow");
        }
        req->r_refs--;
        destroy = (req->r_refs == 0);
        lck_mtx_unlock(&req->r_mtx);
        if (destroy) {
                nfs_request_destroy(req);
        }
}


/*
 * Add an (updated) RPC header with authorization to an NFS request.
 */
int
nfs_request_add_header(struct nfsreq *req)
{
        struct nfsmount *nmp;
        int error = 0;
        mbuf_t m;

        /* free up any previous header */
        if ((m = req->r_mhead)) {
                while (m && (m != req->r_mrest)) {
                        m = mbuf_free(m);
                }
                req->r_mhead = NULL;
        }

        nmp = req->r_nmp;
        if (nfs_mount_gone(nmp)) {
                return ENXIO;
        }

        error = nfsm_rpchead(req, req->r_mrest, &req->r_xid, &req->r_mhead);
        if (error) {
                return error;
        }

        req->r_mreqlen = mbuf_pkthdr_len(req->r_mhead);
        nmp = req->r_nmp;
        if (nfs_mount_gone(nmp)) {
                return ENXIO;
        }
        lck_mtx_lock(&nmp->nm_lock);
        if (NMFLAG(nmp, SOFT) || (req->r_flags & R_SOFT)) {
                req->r_retry = nmp->nm_retry;
        } else {
                req->r_retry = NFS_MAXREXMIT + 1;       /* past clip limit */
        }
        lck_mtx_unlock(&nmp->nm_lock);

        return error;
}


/*
 * Queue an NFS request up and send it out.
 */
int
nfs_request_send(struct nfsreq *req, int wait)
{
        struct nfsmount *nmp;
        struct timeval now;

        lck_mtx_lock(&req->r_mtx);
        req->r_flags |= R_SENDING;
        lck_mtx_unlock(&req->r_mtx);

        lck_mtx_lock(nfs_request_mutex);

        nmp = req->r_nmp;
        if (nfs_mount_gone(nmp)) {
                lck_mtx_unlock(nfs_request_mutex);
                return ENXIO;
        }

        microuptime(&now);
        if (!req->r_start) {
                req->r_start = now.tv_sec;
                req->r_lastmsg = now.tv_sec -
                    ((nmp->nm_tprintf_delay) - (nmp->nm_tprintf_initial_delay));
        }

        OSAddAtomic64(1, &nfsstats.rpcrequests);

        /*
         * Chain request into list of outstanding requests. Be sure
         * to put it LAST so timer finds oldest requests first.
         * Make sure that the request queue timer is running
         * to check for possible request timeout.
         */
        TAILQ_INSERT_TAIL(&nfs_reqq, req, r_chain);
        req->r_lflags |= RL_QUEUED;
        if (!nfs_request_timer_on) {
                nfs_request_timer_on = 1;
                nfs_interval_timer_start(nfs_request_timer_call,
                    NFS_REQUESTDELAY);
        }
        lck_mtx_unlock(nfs_request_mutex);

        /* Send the request... */
        return nfs_send(req, wait);
}

/*
 * Call nfs_wait_reply() to wait for the reply.
 */
void
nfs_request_wait(struct nfsreq *req)
{
        req->r_error = nfs_wait_reply(req);
}

/*
 * Finish up an NFS request by dequeueing it and
 * doing the initial NFS request reply processing.
 */
int
nfs_request_finish(
        struct nfsreq *req,
        struct nfsm_chain *nmrepp,
        int *status)
{
        struct nfsmount *nmp;
        mbuf_t mrep;
        int verf_type = 0;
        uint32_t verf_len = 0;
        uint32_t reply_status = 0;
        uint32_t rejected_status = 0;
        uint32_t auth_status = 0;
        uint32_t accepted_status = 0;
        struct nfsm_chain nmrep;
        int error, clearjbtimeo;

        error = req->r_error;

        if (nmrepp) {
                nmrepp->nmc_mhead = NULL;
        }

        /* RPC done, unlink the request. */
        nfs_reqdequeue(req);

        mrep = req->r_nmrep.nmc_mhead;

        nmp = req->r_nmp;

        if ((req->r_flags & R_CWND) && nmp) {
                /*
                 * Decrement the outstanding request count.
                 */
                req->r_flags &= ~R_CWND;
                lck_mtx_lock(&nmp->nm_lock);
                FSDBG(273, R_XID32(req->r_xid), req, nmp->nm_sent, nmp->nm_cwnd);
                nmp->nm_sent -= NFS_CWNDSCALE;
                if ((nmp->nm_sent < nmp->nm_cwnd) && !TAILQ_EMPTY(&nmp->nm_cwndq)) {
                        /* congestion window is open, poke the cwnd queue */
                        struct nfsreq *req2 = TAILQ_FIRST(&nmp->nm_cwndq);
                        TAILQ_REMOVE(&nmp->nm_cwndq, req2, r_cchain);
                        req2->r_cchain.tqe_next = NFSREQNOLIST;
                        wakeup(req2);
                }
                lck_mtx_unlock(&nmp->nm_lock);
        }

#if CONFIG_NFS_GSS
        if (nfs_request_using_gss(req)) {
                /*
                 * If the request used an RPCSEC_GSS credential
                 * then reset its sequence number bit in the
                 * request window.
                 */
                nfs_gss_clnt_rpcdone(req);

                /*
                 * If we need to re-send, go back and re-build the
                 * request based on a new sequence number.
                 * Note that we're using the original XID.
                 */
                if (error == EAGAIN) {
                        req->r_error = 0;
                        if (mrep) {
                                mbuf_freem(mrep);
                        }
                        error = nfs_gss_clnt_args_restore(req); // remove any trailer mbufs
                        req->r_nmrep.nmc_mhead = NULL;
                        req->r_flags |= R_RESTART;
                        if (error == ENEEDAUTH) {
                                req->r_xid = 0;         // get a new XID
                                error = 0;
                        }
                        goto nfsmout;
                }
        }
#endif /* CONFIG_NFS_GSS */

        /*
         * If there was a successful reply, make sure to mark the mount as up.
         * If a tprintf message was given (or if this is a timed-out soft mount)
         * then post a tprintf message indicating the server is alive again.
         */
        if (!error) {
                if ((req->r_flags & R_TPRINTFMSG) ||
                    (nmp && (NMFLAG(nmp, SOFT) || (req->r_flags & R_SOFT)) &&
                    ((nmp->nm_state & (NFSSTA_TIMEO | NFSSTA_FORCE | NFSSTA_DEAD)) == NFSSTA_TIMEO))) {
                        nfs_up(nmp, req->r_thread, NFSSTA_TIMEO, "is alive again");
                } else {
                        nfs_up(nmp, req->r_thread, NFSSTA_TIMEO, NULL);
                }
        }
        if (!error && !nmp) {
                error = ENXIO;
        }
        nfsmout_if(error);

        /*
         * break down the RPC header and check if ok
         */
        nmrep = req->r_nmrep;
        nfsm_chain_get_32(error, &nmrep, reply_status);
        nfsmout_if(error);
        if (reply_status == RPC_MSGDENIED) {
                nfsm_chain_get_32(error, &nmrep, rejected_status);
                nfsmout_if(error);
                if (rejected_status == RPC_MISMATCH) {
                        error = ENOTSUP;
                        goto nfsmout;
                }
                nfsm_chain_get_32(error, &nmrep, auth_status);
                nfsmout_if(error);
                switch (auth_status) {
#if CONFIG_NFS_GSS
                case RPCSEC_GSS_CREDPROBLEM:
                case RPCSEC_GSS_CTXPROBLEM:
                        /*
                         * An RPCSEC_GSS cred or context problem.
                         * We can't use it anymore.
                         * Restore the args, renew the context
                         * and set up for a resend.
                         */
                        error = nfs_gss_clnt_args_restore(req);
                        if (error && error != ENEEDAUTH) {
                                break;
                        }

                        if (!error) {
                                error = nfs_gss_clnt_ctx_renew(req);
                                if (error) {
                                        break;
                                }
                        }
                        mbuf_freem(mrep);
                        req->r_nmrep.nmc_mhead = NULL;
                        req->r_xid = 0;         // get a new XID
                        req->r_flags |= R_RESTART;
                        goto nfsmout;
#endif /* CONFIG_NFS_GSS */
                default:
                        error = EACCES;
                        break;
                }
                goto nfsmout;
        }

        /* Now check the verifier */
        nfsm_chain_get_32(error, &nmrep, verf_type); // verifier flavor
        nfsm_chain_get_32(error, &nmrep, verf_len);  // verifier length
        nfsmout_if(error);

        switch (req->r_auth) {
        case RPCAUTH_NONE:
        case RPCAUTH_SYS:
                /* Any AUTH_SYS verifier is ignored */
                if (verf_len > 0) {
                        nfsm_chain_adv(error, &nmrep, nfsm_rndup(verf_len));
                }
                nfsm_chain_get_32(error, &nmrep, accepted_status);
                break;
#if CONFIG_NFS_GSS
        case RPCAUTH_KRB5:
        case RPCAUTH_KRB5I:
        case RPCAUTH_KRB5P:
                error = nfs_gss_clnt_verf_get(req, &nmrep,
                    verf_type, verf_len, &accepted_status);
                break;
#endif /* CONFIG_NFS_GSS */
        }
        nfsmout_if(error);

        switch (accepted_status) {
        case RPC_SUCCESS:
                if (req->r_procnum == NFSPROC_NULL) {
                        /*
                         * The NFS null procedure is unique,
                         * in not returning an NFS status.
                         */
                        *status = NFS_OK;
                } else {
                        nfsm_chain_get_32(error, &nmrep, *status);
                        nfsmout_if(error);
                }

                if ((nmp->nm_vers != NFS_VER2) && (*status == NFSERR_TRYLATER)) {
                        /*
                         * It's a JUKEBOX error - delay and try again
                         */
                        int delay, slpflag = (NMFLAG(nmp, INTR) && !(req->r_flags & R_NOINTR)) ? PCATCH : 0;

                        mbuf_freem(mrep);
                        req->r_nmrep.nmc_mhead = NULL;
                        if ((req->r_delay >= 30) && !(nmp->nm_state & NFSSTA_MOUNTED)) {
                                /* we're not yet completely mounted and */
                                /* we can't complete an RPC, so we fail */
                                OSAddAtomic64(1, &nfsstats.rpctimeouts);
                                nfs_softterm(req);
                                error = req->r_error;
                                goto nfsmout;
                        }
                        req->r_delay = !req->r_delay ? NFS_TRYLATERDEL : (req->r_delay * 2);
                        if (req->r_delay > 30) {
                                req->r_delay = 30;
                        }
                        if (nmp->nm_tprintf_initial_delay && (req->r_delay >= nmp->nm_tprintf_initial_delay)) {
                                if (!(req->r_flags & R_JBTPRINTFMSG)) {
                                        req->r_flags |= R_JBTPRINTFMSG;
                                        lck_mtx_lock(&nmp->nm_lock);
                                        nmp->nm_jbreqs++;
                                        lck_mtx_unlock(&nmp->nm_lock);
                                }
                                nfs_down(req->r_nmp, req->r_thread, 0, NFSSTA_JUKEBOXTIMEO,
                                    "resource temporarily unavailable (jukebox)", 0);
                        }
                        if ((NMFLAG(nmp, SOFT) || (req->r_flags & R_SOFT)) && (req->r_delay == 30) &&
                            !(req->r_flags & R_NOINTR)) {
                                /* for soft mounts, just give up after a short while */
                                OSAddAtomic64(1, &nfsstats.rpctimeouts);
                                nfs_softterm(req);
                                error = req->r_error;
                                goto nfsmout;
                        }
                        delay = req->r_delay;
                        if (req->r_callback.rcb_func) {
                                struct timeval now;
                                microuptime(&now);
                                req->r_resendtime = now.tv_sec + delay;
                        } else {
                                do {
                                        if ((error = nfs_sigintr(req->r_nmp, req, req->r_thread, 0))) {
                                                goto nfsmout;
                                        }
                                        tsleep(nfs_request_finish, PSOCK | slpflag, "nfs_jukebox_trylater", hz);
                                        slpflag = 0;
                                } while (--delay > 0);
                        }
                        req->r_xid = 0;                 // get a new XID
                        req->r_flags |= R_RESTART;
                        req->r_start = 0;
                        FSDBG(273, R_XID32(req->r_xid), nmp, req, NFSERR_TRYLATER);
                        return 0;
                }

                if (req->r_flags & R_JBTPRINTFMSG) {
                        req->r_flags &= ~R_JBTPRINTFMSG;
                        lck_mtx_lock(&nmp->nm_lock);
                        nmp->nm_jbreqs--;
                        clearjbtimeo = (nmp->nm_jbreqs == 0) ? NFSSTA_JUKEBOXTIMEO : 0;
                        lck_mtx_unlock(&nmp->nm_lock);
                        nfs_up(nmp, req->r_thread, clearjbtimeo, "resource available again");
                }

#if CONFIG_NFS4
                if ((nmp->nm_vers >= NFS_VER4) && (*status == NFSERR_WRONGSEC)) {
                        /*
                         * Hmmm... we need to try a different security flavor.
                         * The first time a request hits this, we will allocate an array
                         * to track flavors to try.  We fill the array with the mount's
                         * preferred flavors or the server's preferred flavors or just the
                         * flavors we support.
                         */
                        uint32_t srvflavors[NX_MAX_SEC_FLAVORS];
                        int srvcount, i, j;

                        /* Call SECINFO to try to get list of flavors from server. */
                        srvcount = NX_MAX_SEC_FLAVORS;
                        nfs4_secinfo_rpc(nmp, &req->r_secinfo, req->r_cred, srvflavors, &srvcount);

                        if (!req->r_wrongsec) {
                                /* first time... set up flavor array */
                                MALLOC(req->r_wrongsec, uint32_t*, NX_MAX_SEC_FLAVORS * sizeof(uint32_t), M_TEMP, M_WAITOK);
                                if (!req->r_wrongsec) {
                                        error = EACCES;
                                        goto nfsmout;
                                }
                                i = 0;
                                if (nmp->nm_sec.count) { /* use the mount's preferred list of flavors */
                                        for (; i < nmp->nm_sec.count; i++) {
                                                req->r_wrongsec[i] = nmp->nm_sec.flavors[i];
                                        }
                                } else if (srvcount) { /* otherwise use the server's list of flavors */
                                        for (; i < srvcount; i++) {
                                                req->r_wrongsec[i] = srvflavors[i];
                                        }
                                } else { /* otherwise, just try the flavors we support. */
                                        req->r_wrongsec[i++] = RPCAUTH_KRB5P;
                                        req->r_wrongsec[i++] = RPCAUTH_KRB5I;
                                        req->r_wrongsec[i++] = RPCAUTH_KRB5;
                                        req->r_wrongsec[i++] = RPCAUTH_SYS;
                                        req->r_wrongsec[i++] = RPCAUTH_NONE;
                                }
                                for (; i < NX_MAX_SEC_FLAVORS; i++) { /* invalidate any remaining slots */
                                        req->r_wrongsec[i] = RPCAUTH_INVALID;
                                }
                        }

                        /* clear the current flavor from the list */
                        for (i = 0; i < NX_MAX_SEC_FLAVORS; i++) {
                                if (req->r_wrongsec[i] == req->r_auth) {
                                        req->r_wrongsec[i] = RPCAUTH_INVALID;
                                }
                        }

                        /* find the next flavor to try */
                        for (i = 0; i < NX_MAX_SEC_FLAVORS; i++) {
                                if (req->r_wrongsec[i] != RPCAUTH_INVALID) {
                                        if (!srvcount) { /* no server list, just try it */
                                                break;
                                        }
                                        /* check that it's in the server's list */
                                        for (j = 0; j < srvcount; j++) {
                                                if (req->r_wrongsec[i] == srvflavors[j]) {
                                                        break;
                                                }
                                        }
                                        if (j < srvcount) { /* found */
                                                break;
                                        }
                                        /* not found in server list */
                                        req->r_wrongsec[i] = RPCAUTH_INVALID;
                                }
                        }
                        if (i == NX_MAX_SEC_FLAVORS) {
                                /* nothing left to try! */
                                error = EACCES;
                                goto nfsmout;
                        }

                        /* retry with the next auth flavor */
                        req->r_auth = req->r_wrongsec[i];
                        req->r_xid = 0;                 // get a new XID
                        req->r_flags |= R_RESTART;
                        req->r_start = 0;
                        FSDBG(273, R_XID32(req->r_xid), nmp, req, NFSERR_WRONGSEC);
                        return 0;
                }
                if ((nmp->nm_vers >= NFS_VER4) && req->r_wrongsec) {
                        /*
                         * We renegotiated security for this request; so update the
                         * default security flavor for the associated node.
                         */
                        if (req->r_np) {
                                req->r_np->n_auth = req->r_auth;
                        }
                }
#endif /* CONFIG_NFS4 */
                if (*status == NFS_OK) {
                        /*
                         * Successful NFS request
                         */
                        *nmrepp = nmrep;
                        req->r_nmrep.nmc_mhead = NULL;
                        break;
                }
                /* Got an NFS error of some kind */

                /*
                 * If the File Handle was stale, invalidate the
                 * lookup cache, just in case.
                 */
                if ((*status == ESTALE) && req->r_np) {
                        cache_purge(NFSTOV(req->r_np));
                        /* if monitored, also send delete event */
                        if (vnode_ismonitored(NFSTOV(req->r_np))) {
                                nfs_vnode_notify(req->r_np, (VNODE_EVENT_ATTRIB | VNODE_EVENT_DELETE));
                        }
                }
                if (nmp->nm_vers == NFS_VER2) {
                        mbuf_freem(mrep);
                } else {
                        *nmrepp = nmrep;
                }
                req->r_nmrep.nmc_mhead = NULL;
                error = 0;
                break;
        case RPC_PROGUNAVAIL:
                error = EPROGUNAVAIL;
                break;
        case RPC_PROGMISMATCH:
                error = ERPCMISMATCH;
                break;
        case RPC_PROCUNAVAIL:
                error = EPROCUNAVAIL;
                break;
        case RPC_GARBAGE:
                error = EBADRPC;
                break;
        case RPC_SYSTEM_ERR:
        default:
                error = EIO;
                break;
        }
nfsmout:
        if (req->r_flags & R_JBTPRINTFMSG) {
                req->r_flags &= ~R_JBTPRINTFMSG;
                lck_mtx_lock(&nmp->nm_lock);
                nmp->nm_jbreqs--;
                clearjbtimeo = (nmp->nm_jbreqs == 0) ? NFSSTA_JUKEBOXTIMEO : 0;
                lck_mtx_unlock(&nmp->nm_lock);
                if (clearjbtimeo) {
                        nfs_up(nmp, req->r_thread, clearjbtimeo, NULL);
                }
        }
        FSDBG(273, R_XID32(req->r_xid), nmp, req,
            (!error && (*status == NFS_OK)) ? 0xf0f0f0f0 : error);
        return error;
}

/*
 * NFS request using a GSS/Kerberos security flavor?
 */
int
nfs_request_using_gss(struct nfsreq *req)
{
        if (!req->r_gss_ctx) {
                return 0;
        }
        switch (req->r_auth) {
        case RPCAUTH_KRB5:
        case RPCAUTH_KRB5I:
        case RPCAUTH_KRB5P:
                return 1;
        }
        return 0;
}

/*
 * Perform an NFS request synchronously.
 */

int
nfs_request(
        nfsnode_t np,
        mount_t mp,     /* used only if !np */
        struct nfsm_chain *nmrest,
        int procnum,
        vfs_context_t ctx,
        struct nfsreq_secinfo_args *si,
        struct nfsm_chain *nmrepp,
        u_int64_t *xidp,
        int *status)
{
        return nfs_request2(np, mp, nmrest, procnum,
                   vfs_context_thread(ctx), vfs_context_ucred(ctx),
                   si, 0, nmrepp, xidp, status);
}

int
nfs_request2(
        nfsnode_t np,
        mount_t mp,     /* used only if !np */
        struct nfsm_chain *nmrest,
        int procnum,
        thread_t thd,
        kauth_cred_t cred,
        struct nfsreq_secinfo_args *si,
        int flags,
        struct nfsm_chain *nmrepp,
        u_int64_t *xidp,
        int *status)
{
        struct nfsreq rq, *req = &rq;
        int error;

        if ((error = nfs_request_create(np, mp, nmrest, procnum, thd, cred, &req))) {
                return error;
        }
        req->r_flags |= (flags & (R_OPTMASK | R_SOFT));
        if (si) {
                req->r_secinfo = *si;
        }

        FSDBG_TOP(273, R_XID32(req->r_xid), np, procnum, 0);
        do {
                req->r_error = 0;
                req->r_flags &= ~R_RESTART;
                if ((error = nfs_request_add_header(req))) {
                        break;
                }
                if (xidp) {
                        *xidp = req->r_xid;
                }
                if ((error = nfs_request_send(req, 1))) {
                        break;
                }
                nfs_request_wait(req);
                if ((error = nfs_request_finish(req, nmrepp, status))) {
                        break;
                }
        } while (req->r_flags & R_RESTART);

        FSDBG_BOT(273, R_XID32(req->r_xid), np, procnum, error);
        nfs_request_rele(req);
        return error;
}


#if CONFIG_NFS_GSS
/*
 * Set up a new null proc request to exchange GSS context tokens with the
 * server. Associate the context that we are setting up with the request that we
 * are sending.
 */

int
nfs_request_gss(
        mount_t mp,
        struct nfsm_chain *nmrest,
        thread_t thd,
        kauth_cred_t cred,
        int flags,
        struct nfs_gss_clnt_ctx *cp,           /* Set to gss context to renew or setup */
        struct nfsm_chain *nmrepp,
        int *status)
{
        struct nfsreq rq, *req = &rq;
        int error, wait = 1;

        if ((error = nfs_request_create(NULL, mp, nmrest, NFSPROC_NULL, thd, cred, &req))) {
                return error;
        }
        req->r_flags |= (flags & R_OPTMASK);

        if (cp == NULL) {
                printf("nfs_request_gss request has no context\n");
                nfs_request_rele(req);
                return NFSERR_EAUTH;
        }
        nfs_gss_clnt_ctx_ref(req, cp);

        /*
         * Don't wait for a reply to a context destroy advisory
         * to avoid hanging on a dead server.
         */
        if (cp->gss_clnt_proc == RPCSEC_GSS_DESTROY) {
                wait = 0;
        }

        FSDBG_TOP(273, R_XID32(req->r_xid), NULL, NFSPROC_NULL, 0);
        do {
                req->r_error = 0;
                req->r_flags &= ~R_RESTART;
                if ((error = nfs_request_add_header(req))) {
                        break;
                }

                if ((error = nfs_request_send(req, wait))) {
                        break;
                }
                if (!wait) {
                        break;
                }

                nfs_request_wait(req);
                if ((error = nfs_request_finish(req, nmrepp, status))) {
                        break;
                }
        } while (req->r_flags & R_RESTART);

        FSDBG_BOT(273, R_XID32(req->r_xid), NULL, NFSPROC_NULL, error);

        nfs_gss_clnt_ctx_unref(req);
        nfs_request_rele(req);

        return error;
}
#endif /* CONFIG_NFS_GSS */

/*
 * Create and start an asynchronous NFS request.
 */
int
nfs_request_async(
        nfsnode_t np,
        mount_t mp,     /* used only if !np */
        struct nfsm_chain *nmrest,
        int procnum,
        thread_t thd,
        kauth_cred_t cred,
        struct nfsreq_secinfo_args *si,
        int flags,
        struct nfsreq_cbinfo *cb,
        struct nfsreq **reqp)
{
        struct nfsreq *req;
        struct nfsmount *nmp;
        int error, sent;

        error = nfs_request_create(np, mp, nmrest, procnum, thd, cred, reqp);
        req = *reqp;
        FSDBG(274, (req ? R_XID32(req->r_xid) : 0), np, procnum, error);
        if (error) {
                return error;
        }
        req->r_flags |= (flags & R_OPTMASK);
        req->r_flags |= R_ASYNC;
        if (si) {
                req->r_secinfo = *si;
        }
        if (cb) {
                req->r_callback = *cb;
        }
        error = nfs_request_add_header(req);
        if (!error) {
                req->r_flags |= R_WAITSENT;
                if (req->r_callback.rcb_func) {
                        nfs_request_ref(req, 0);
                }
                error = nfs_request_send(req, 1);
                lck_mtx_lock(&req->r_mtx);
                if (!error && !(req->r_flags & R_SENT) && req->r_callback.rcb_func) {
                        /* make sure to wait until this async I/O request gets sent */
                        int slpflag = (req->r_nmp && NMFLAG(req->r_nmp, INTR) && req->r_thread && !(req->r_flags & R_NOINTR)) ? PCATCH : 0;
                        struct timespec ts = { .tv_sec = 2, .tv_nsec = 0 };
                        while (!(req->r_flags & R_SENT)) {
                                nmp = req->r_nmp;
                                if ((req->r_flags & R_RESENDQ) && !nfs_mount_gone(nmp)) {
                                        lck_mtx_lock(&nmp->nm_lock);
                                        if ((nmp->nm_state & NFSSTA_RECOVER) && (req->r_rchain.tqe_next != NFSREQNOLIST)) {
                                                /*
                                                 * It's not going to get off the resend queue if we're in recovery.
                                                 * So, just take it off ourselves.  We could be holding mount state
                                                 * busy and thus holding up the start of recovery.
                                                 */
                                                TAILQ_REMOVE(&nmp->nm_resendq, req, r_rchain);
                                                req->r_rchain.tqe_next = NFSREQNOLIST;
                                                if (req->r_flags & R_RESENDQ) {
                                                        req->r_flags &= ~R_RESENDQ;
                                                }
                                                lck_mtx_unlock(&nmp->nm_lock);
                                                req->r_flags |= R_SENDING;
                                                lck_mtx_unlock(&req->r_mtx);
                                                error = nfs_send(req, 1);
                                                /* Remove the R_RESENDQ reference */
                                                nfs_request_rele(req);
                                                lck_mtx_lock(&req->r_mtx);
                                                if (error) {
                                                        break;
                                                }
                                                continue;
                                        }
                                        lck_mtx_unlock(&nmp->nm_lock);
                                }
                                if ((error = nfs_sigintr(req->r_nmp, req, req->r_thread, 0))) {
                                        break;
                                }
                                msleep(req, &req->r_mtx, slpflag | (PZERO - 1), "nfswaitsent", &ts);
                                slpflag = 0;
                        }
                }
                sent = req->r_flags & R_SENT;
                lck_mtx_unlock(&req->r_mtx);
                if (error && req->r_callback.rcb_func && !sent) {
                        nfs_request_rele(req);
                }
        }
        FSDBG(274, R_XID32(req->r_xid), np, procnum, error);
        if (error || req->r_callback.rcb_func) {
                nfs_request_rele(req);
        }

        return error;
}

/*
 * Wait for and finish an asynchronous NFS request.
 */
int
nfs_request_async_finish(
        struct nfsreq *req,
        struct nfsm_chain *nmrepp,
        u_int64_t *xidp,
        int *status)
{
        int error = 0, asyncio = req->r_callback.rcb_func ? 1 : 0;
        struct nfsmount *nmp;

        lck_mtx_lock(&req->r_mtx);
        if (!asyncio) {
                req->r_flags |= R_ASYNCWAIT;
        }
        while (req->r_flags & R_RESENDQ) {  /* wait until the request is off the resend queue */
                struct timespec ts = { .tv_sec = 2, .tv_nsec = 0 };

                if ((nmp = req->r_nmp)) {
                        lck_mtx_lock(&nmp->nm_lock);
                        if ((nmp->nm_state & NFSSTA_RECOVER) && (req->r_rchain.tqe_next != NFSREQNOLIST)) {
                                /*
                                 * It's not going to get off the resend queue if we're in recovery.
                                 * So, just take it off ourselves.  We could be holding mount state
                                 * busy and thus holding up the start of recovery.
                                 */
                                TAILQ_REMOVE(&nmp->nm_resendq, req, r_rchain);
                                req->r_rchain.tqe_next = NFSREQNOLIST;
                                if (req->r_flags & R_RESENDQ) {
                                        req->r_flags &= ~R_RESENDQ;
                                }
                                /* Remove the R_RESENDQ reference */
                                assert(req->r_refs > 0);
                                req->r_refs--;
                                lck_mtx_unlock(&nmp->nm_lock);
                                break;
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                }
                if ((error = nfs_sigintr(req->r_nmp, req, req->r_thread, 0))) {
                        break;
                }
                msleep(req, &req->r_mtx, PZERO - 1, "nfsresendqwait", &ts);
        }
        lck_mtx_unlock(&req->r_mtx);

        if (!error) {
                nfs_request_wait(req);
                error = nfs_request_finish(req, nmrepp, status);
        }

        while (!error && (req->r_flags & R_RESTART)) {
                if (asyncio) {
                        assert(req->r_achain.tqe_next == NFSREQNOLIST);
                        lck_mtx_lock(&req->r_mtx);
                        req->r_flags &= ~R_IOD;
                        if (req->r_resendtime) {  /* send later */
                                nfs_asyncio_resend(req);
                                lck_mtx_unlock(&req->r_mtx);
                                return EINPROGRESS;
                        }
                        lck_mtx_unlock(&req->r_mtx);
                }
                req->r_error = 0;
                req->r_flags &= ~R_RESTART;
                if ((error = nfs_request_add_header(req))) {
                        break;
                }
                if ((error = nfs_request_send(req, !asyncio))) {
                        break;
                }
                if (asyncio) {
                        return EINPROGRESS;
                }
                nfs_request_wait(req);
                if ((error = nfs_request_finish(req, nmrepp, status))) {
                        break;
                }
        }
        if (xidp) {
                *xidp = req->r_xid;
        }

        FSDBG(275, R_XID32(req->r_xid), req->r_np, req->r_procnum, error);
        nfs_request_rele(req);
        return error;
}

/*
 * Cancel a pending asynchronous NFS request.
 */
void
nfs_request_async_cancel(struct nfsreq *req)
{
        FSDBG(275, R_XID32(req->r_xid), req->r_np, req->r_procnum, 0xD1ED1E);
        nfs_request_rele(req);
}

/*
 * Flag a request as being terminated.
 */
void
nfs_softterm(struct nfsreq *req)
{
        struct nfsmount *nmp = req->r_nmp;
        req->r_flags |= R_SOFTTERM;
        req->r_error = ETIMEDOUT;
        if (!(req->r_flags & R_CWND) || nfs_mount_gone(nmp)) {
                return;
        }
        /* update congestion window */
        req->r_flags &= ~R_CWND;
        lck_mtx_lock(&nmp->nm_lock);
        FSDBG(532, R_XID32(req->r_xid), req, nmp->nm_sent, nmp->nm_cwnd);
        nmp->nm_sent -= NFS_CWNDSCALE;
        if ((nmp->nm_sent < nmp->nm_cwnd) && !TAILQ_EMPTY(&nmp->nm_cwndq)) {
                /* congestion window is open, poke the cwnd queue */
                struct nfsreq *req2 = TAILQ_FIRST(&nmp->nm_cwndq);
                TAILQ_REMOVE(&nmp->nm_cwndq, req2, r_cchain);
                req2->r_cchain.tqe_next = NFSREQNOLIST;
                wakeup(req2);
        }
        lck_mtx_unlock(&nmp->nm_lock);
}

/*
 * Ensure req isn't in use by the timer, then dequeue it.
 */
void
nfs_reqdequeue(struct nfsreq *req)
{
        lck_mtx_lock(nfs_request_mutex);
        while (req->r_lflags & RL_BUSY) {
                req->r_lflags |= RL_WAITING;
                msleep(&req->r_lflags, nfs_request_mutex, PSOCK, "reqdeq", NULL);
        }
        if (req->r_lflags & RL_QUEUED) {
                TAILQ_REMOVE(&nfs_reqq, req, r_chain);
                req->r_lflags &= ~RL_QUEUED;
        }
        lck_mtx_unlock(nfs_request_mutex);
}

/*
 * Busy (lock) a nfsreq, used by the nfs timer to make sure it's not
 * free()'d out from under it.
 */
void
nfs_reqbusy(struct nfsreq *req)
{
        if (req->r_lflags & RL_BUSY) {
                panic("req locked");
        }
        req->r_lflags |= RL_BUSY;
}

/*
 * Unbusy the nfsreq passed in, return the next nfsreq in the chain busied.
 */
struct nfsreq *
nfs_reqnext(struct nfsreq *req)
{
        struct nfsreq * nextreq;

        if (req == NULL) {
                return NULL;
        }
        /*
         * We need to get and busy the next req before signalling the
         * current one, otherwise wakeup() may block us and we'll race to
         * grab the next req.
         */
        nextreq = TAILQ_NEXT(req, r_chain);
        if (nextreq != NULL) {
                nfs_reqbusy(nextreq);
        }
        /* unbusy and signal. */
        req->r_lflags &= ~RL_BUSY;
        if (req->r_lflags & RL_WAITING) {
                req->r_lflags &= ~RL_WAITING;
                wakeup(&req->r_lflags);
        }
        return nextreq;
}

/*
 * NFS request queue timer routine
 *
 * Scan the NFS request queue for any requests that have timed out.
 *
 * Alert the system of unresponsive servers.
 * Mark expired requests on soft mounts as terminated.
 * For UDP, mark/signal requests for retransmission.
 */
void
nfs_request_timer(__unused void *param0, __unused void *param1)
{
        struct nfsreq *req;
        struct nfsmount *nmp;
        int timeo, maxtime, finish_asyncio, error;
        struct timeval now;
        TAILQ_HEAD(nfs_mount_pokeq, nfsmount) nfs_mount_poke_queue;
        TAILQ_INIT(&nfs_mount_poke_queue);

restart:
        lck_mtx_lock(nfs_request_mutex);
        req = TAILQ_FIRST(&nfs_reqq);
        if (req == NULL) {      /* no requests - turn timer off */
                nfs_request_timer_on = 0;
                lck_mtx_unlock(nfs_request_mutex);
                return;
        }

        nfs_reqbusy(req);

        microuptime(&now);
        for (; req != NULL; req = nfs_reqnext(req)) {
                nmp = req->r_nmp;
                if (nmp == NULL) {
                        NFS_SOCK_DBG("Found a request with out a mount!\n");
                        continue;
                }
                if (req->r_error || req->r_nmrep.nmc_mhead) {
                        continue;
                }
                if ((error = nfs_sigintr(nmp, req, req->r_thread, 0))) {
                        if (req->r_callback.rcb_func != NULL) {
                                /* async I/O RPC needs to be finished */
                                lck_mtx_lock(&req->r_mtx);
                                req->r_error = error;
                                finish_asyncio = !(req->r_flags & R_WAITSENT);
                                wakeup(req);
                                lck_mtx_unlock(&req->r_mtx);
                                if (finish_asyncio) {
                                        nfs_asyncio_finish(req);
                                }
                        }
                        continue;
                }

                lck_mtx_lock(&req->r_mtx);

                if (nmp->nm_tprintf_initial_delay &&
                    ((req->r_rexmit > 2) || (req->r_flags & R_RESENDERR)) &&
                    ((req->r_lastmsg + nmp->nm_tprintf_delay) < now.tv_sec)) {
                        req->r_lastmsg = now.tv_sec;
                        nfs_down(req->r_nmp, req->r_thread, 0, NFSSTA_TIMEO,
                            "not responding", 1);
                        req->r_flags |= R_TPRINTFMSG;
                        lck_mtx_lock(&nmp->nm_lock);
                        if (!(nmp->nm_state & NFSSTA_MOUNTED)) {
                                lck_mtx_unlock(&nmp->nm_lock);
                                /* we're not yet completely mounted and */
                                /* we can't complete an RPC, so we fail */
                                OSAddAtomic64(1, &nfsstats.rpctimeouts);
                                nfs_softterm(req);
                                finish_asyncio = ((req->r_callback.rcb_func != NULL) && !(req->r_flags & R_WAITSENT));
                                wakeup(req);
                                lck_mtx_unlock(&req->r_mtx);
                                if (finish_asyncio) {
                                        nfs_asyncio_finish(req);
                                }
                                continue;
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                }

                /*
                 * Put a reasonable limit on the maximum timeout,
                 * and reduce that limit when soft mounts get timeouts or are in reconnect.
                 */
                if (!(NMFLAG(nmp, SOFT) || (req->r_flags & R_SOFT)) && !nfs_can_squish(nmp)) {
                        maxtime = NFS_MAXTIMEO;
                } else if ((req->r_flags & (R_SETUP | R_RECOVER)) ||
                    ((nmp->nm_reconnect_start <= 0) || ((now.tv_sec - nmp->nm_reconnect_start) < 8))) {
                        maxtime = (NFS_MAXTIMEO / (nmp->nm_timeouts + 1)) / 2;
                } else {
                        maxtime = NFS_MINTIMEO / 4;
                }

                /*
                 * Check for request timeout.
                 */
                if (req->r_rtt >= 0) {
                        req->r_rtt++;
                        lck_mtx_lock(&nmp->nm_lock);
                        if (req->r_flags & R_RESENDERR) {
                                /* with resend errors, retry every few seconds */
                                timeo = 4 * hz;
                        } else {
                                if (req->r_procnum == NFSPROC_NULL && req->r_gss_ctx != NULL) {
                                        timeo = NFS_MINIDEMTIMEO; // gss context setup
                                } else if (NMFLAG(nmp, DUMBTIMER)) {
                                        timeo = nmp->nm_timeo;
                                } else {
                                        timeo = NFS_RTO(nmp, proct[req->r_procnum]);
                                }

                                /* ensure 62.5 ms floor */
                                while (16 * timeo < hz) {
                                        timeo *= 2;
                                }
                                if (nmp->nm_timeouts > 0) {
                                        timeo *= nfs_backoff[nmp->nm_timeouts - 1];
                                }
                        }
                        /* limit timeout to max */
                        if (timeo > maxtime) {
                                timeo = maxtime;
                        }
                        if (req->r_rtt <= timeo) {
                                NFS_SOCK_DBG("nfs timeout: req time %d and timeo is %d continue\n", req->r_rtt, timeo);
                                lck_mtx_unlock(&nmp->nm_lock);
                                lck_mtx_unlock(&req->r_mtx);
                                continue;
                        }
                        /* The request has timed out */
                        NFS_SOCK_DBG("nfs timeout: proc %d %d xid %llx rtt %d to %d # %d, t %ld/%d\n",
                            req->r_procnum, proct[req->r_procnum],
                            req->r_xid, req->r_rtt, timeo, nmp->nm_timeouts,
                            (now.tv_sec - req->r_start) * NFS_HZ, maxtime);
                        if (nmp->nm_timeouts < 8) {
                                nmp->nm_timeouts++;
                        }
                        if (nfs_mount_check_dead_timeout(nmp)) {
                                /* Unbusy this request */
                                req->r_lflags &= ~RL_BUSY;
                                if (req->r_lflags & RL_WAITING) {
                                        req->r_lflags &= ~RL_WAITING;
                                        wakeup(&req->r_lflags);
                                }
                                lck_mtx_unlock(&req->r_mtx);

                                /* No need to poke this mount */
                                if (nmp->nm_sockflags & NMSOCK_POKE) {
                                        nmp->nm_sockflags &= ~NMSOCK_POKE;
                                        TAILQ_REMOVE(&nfs_mount_poke_queue, nmp, nm_pokeq);
                                }
                                /* Release our lock state, so we can become a zombie */
                                lck_mtx_unlock(nfs_request_mutex);

                                /*
                                 * Note nfs_mount_make zombie(nmp) must be
                                 * called with nm_lock held. After doing some
                                 * work we release nm_lock in
                                 * nfs_make_mount_zombie with out acquiring any
                                 * other locks. (Later, in nfs_mount_zombie we
                                 * will acquire nfs_request_mutex, r_mtx,
                                 * nm_lock in that order). So we should not be
                                 * introducing deadlock here. We take a reference
                                 * on the mount so that its still there when we
                                 * release the lock.
                                 */
                                nmp->nm_ref++;
                                nfs_mount_make_zombie(nmp);
                                lck_mtx_unlock(&nmp->nm_lock);
                                nfs_mount_rele(nmp);

                                /*
                                 * All the request for this mount have now been
                                 * removed from the request queue. Restart to
                                 * process the remaining mounts
                                 */
                                goto restart;
                        }

                        /* if it's been a few seconds, try poking the socket */
                        if ((nmp->nm_sotype == SOCK_STREAM) &&
                            ((now.tv_sec - req->r_start) >= 3) &&
                            !(nmp->nm_sockflags & (NMSOCK_POKE | NMSOCK_UNMOUNT)) &&
                            (nmp->nm_sockflags & NMSOCK_READY)) {
                                nmp->nm_sockflags |= NMSOCK_POKE;
                                /*
                                 * We take a ref on the mount so that we know the mount will still be there
                                 * when we process the nfs_mount_poke_queue. An unmount request will block
                                 * in nfs_mount_drain_and_cleanup until after the poke is finished. We release
                                 * the reference after calling nfs_sock_poke below;
                                 */
                                nmp->nm_ref++;
                                TAILQ_INSERT_TAIL(&nfs_mount_poke_queue, nmp, nm_pokeq);
                        }
                        lck_mtx_unlock(&nmp->nm_lock);
                }

                /* For soft mounts (& SETUPs/RECOVERs), check for too many retransmits/timeout. */
                if ((NMFLAG(nmp, SOFT) || (req->r_flags & (R_SETUP | R_RECOVER | R_SOFT))) &&
                    ((req->r_rexmit >= req->r_retry) || /* too many */
                    ((now.tv_sec - req->r_start) * NFS_HZ > maxtime))) { /* too long */
                        OSAddAtomic64(1, &nfsstats.rpctimeouts);
                        lck_mtx_lock(&nmp->nm_lock);
                        if (!(nmp->nm_state & NFSSTA_TIMEO)) {
                                lck_mtx_unlock(&nmp->nm_lock);
                                /* make sure we note the unresponsive server */
                                /* (maxtime may be less than tprintf delay) */
                                nfs_down(req->r_nmp, req->r_thread, 0, NFSSTA_TIMEO,
                                    "not responding", 1);
                                req->r_lastmsg = now.tv_sec;
                                req->r_flags |= R_TPRINTFMSG;
                        } else {
                                lck_mtx_unlock(&nmp->nm_lock);
                        }
                        if (req->r_flags & R_NOINTR) {
                                /* don't terminate nointr requests on timeout */
                                lck_mtx_unlock(&req->r_mtx);
                                continue;
                        }
                        NFS_SOCK_DBG("nfs timer TERMINATE: p %d x 0x%llx f 0x%x rtt %d t %ld\n",
                            req->r_procnum, req->r_xid, req->r_flags, req->r_rtt,
                            now.tv_sec - req->r_start);
                        nfs_softterm(req);
                        finish_asyncio = ((req->r_callback.rcb_func != NULL) && !(req->r_flags & R_WAITSENT));
                        wakeup(req);
                        lck_mtx_unlock(&req->r_mtx);
                        if (finish_asyncio) {
                                nfs_asyncio_finish(req);
                        }
                        continue;
                }

                /* for TCP, only resend if explicitly requested */
                if ((nmp->nm_sotype == SOCK_STREAM) && !(req->r_flags & R_MUSTRESEND)) {
                        if (++req->r_rexmit > NFS_MAXREXMIT) {
                                req->r_rexmit = NFS_MAXREXMIT;
                        }
                        req->r_rtt = 0;
                        lck_mtx_unlock(&req->r_mtx);
                        continue;
                }

                /*
                 * The request needs to be (re)sent.  Kick the requester to resend it.
                 * (unless it's already marked as needing a resend)
                 */
                if ((req->r_flags & R_MUSTRESEND) && (req->r_rtt == -1)) {
                        lck_mtx_unlock(&req->r_mtx);
                        continue;
                }
                NFS_SOCK_DBG("nfs timer mark resend: p %d x 0x%llx f 0x%x rtt %d\n",
                    req->r_procnum, req->r_xid, req->r_flags, req->r_rtt);
                req->r_flags |= R_MUSTRESEND;
                req->r_rtt = -1;
                wakeup(req);
                if ((req->r_flags & (R_IOD | R_ASYNC | R_ASYNCWAIT | R_SENDING)) == R_ASYNC) {
                        nfs_asyncio_resend(req);
                }
                lck_mtx_unlock(&req->r_mtx);
        }

        lck_mtx_unlock(nfs_request_mutex);

        /* poke any sockets */
        while ((nmp = TAILQ_FIRST(&nfs_mount_poke_queue))) {
                TAILQ_REMOVE(&nfs_mount_poke_queue, nmp, nm_pokeq);
                nfs_sock_poke(nmp);
                nfs_mount_rele(nmp);
        }

        nfs_interval_timer_start(nfs_request_timer_call, NFS_REQUESTDELAY);
}

/*
 * check a thread's proc for the "noremotehang" flag.
 */
int
nfs_noremotehang(thread_t thd)
{
        proc_t p = thd ? get_bsdthreadtask_info(thd) : NULL;
        return p && proc_noremotehang(p);
}

/*
 * Test for a termination condition pending on the process.
 * This is used to determine if we need to bail on a mount.
 * ETIMEDOUT is returned if there has been a soft timeout.
 * EINTR is returned if there is a signal pending that is not being ignored
 * and the mount is interruptable, or if we are a thread that is in the process
 * of cancellation (also SIGKILL posted).
 */
extern int sigprop[NSIG + 1];
int
nfs_sigintr(struct nfsmount *nmp, struct nfsreq *req, thread_t thd, int nmplocked)
{
        proc_t p;
        int error = 0;

        if (!nmp) {
                return ENXIO;
        }

        if (req && (req->r_flags & R_SOFTTERM)) {
                return ETIMEDOUT; /* request has been terminated. */
        }
        if (req && (req->r_flags & R_NOINTR)) {
                thd = NULL; /* don't check for signal on R_NOINTR */
        }
        if (!nmplocked) {
                lck_mtx_lock(&nmp->nm_lock);
        }
        if (nmp->nm_state & NFSSTA_FORCE) {
                /* If a force unmount is in progress then fail. */
                error = EIO;
        } else if (vfs_isforce(nmp->nm_mountp)) {
                /* Someone is unmounting us, go soft and mark it. */
                NFS_BITMAP_SET(nmp->nm_flags, NFS_MFLAG_SOFT);
                nmp->nm_state |= NFSSTA_FORCE;
        }

        /* Check if the mount is marked dead. */
        if (!error && (nmp->nm_state & NFSSTA_DEAD)) {
                error = ENXIO;
        }

        /*
         * If the mount is hung and we've requested not to hang
         * on remote filesystems, then bail now.
         */
        if (current_proc() != kernproc &&
            !error && (nmp->nm_state & NFSSTA_TIMEO) && nfs_noremotehang(thd)) {
                error = EIO;
        }

        if (!nmplocked) {
                lck_mtx_unlock(&nmp->nm_lock);
        }
        if (error) {
                return error;
        }

        /* may not have a thread for async I/O */
        if (thd == NULL || current_proc() == kernproc) {
                return 0;
        }

        /*
         * Check if the process is aborted, but don't interrupt if we
         * were killed by a signal and this is the exiting thread which
         * is attempting to dump core.
         */
        if (((p = current_proc()) != kernproc) && current_thread_aborted() &&
            (!(p->p_acflag & AXSIG) || (p->exit_thread != current_thread()) ||
            (p->p_sigacts == NULL) ||
            (p->p_sigacts->ps_sig < 1) || (p->p_sigacts->ps_sig > NSIG) ||
            !(sigprop[p->p_sigacts->ps_sig] & SA_CORE))) {
                return EINTR;
        }

        /* mask off thread and process blocked signals. */
        if (NMFLAG(nmp, INTR) && ((p = get_bsdthreadtask_info(thd))) &&
            proc_pendingsignals(p, NFSINT_SIGMASK)) {
                return EINTR;
        }
        return 0;
}

/*
 * Lock a socket against others.
 * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
 * and also to avoid race conditions between the processes with nfs requests
 * in progress when a reconnect is necessary.
 */
int
nfs_sndlock(struct nfsreq *req)
{
        struct nfsmount *nmp = req->r_nmp;
        int *statep;
        int error = 0, slpflag = 0;
        struct timespec ts = { .tv_sec = 0, .tv_nsec = 0 };

        if (nfs_mount_gone(nmp)) {
                return ENXIO;
        }

        lck_mtx_lock(&nmp->nm_lock);
        statep = &nmp->nm_state;

        if (NMFLAG(nmp, INTR) && req->r_thread && !(req->r_flags & R_NOINTR)) {
                slpflag = PCATCH;
        }
        while (*statep & NFSSTA_SNDLOCK) {
                if ((error = nfs_sigintr(nmp, req, req->r_thread, 1))) {
                        break;
                }
                *statep |= NFSSTA_WANTSND;
                if (nfs_noremotehang(req->r_thread)) {
                        ts.tv_sec = 1;
                }
                msleep(statep, &nmp->nm_lock, slpflag | (PZERO - 1), "nfsndlck", &ts);
                if (slpflag == PCATCH) {
                        slpflag = 0;
                        ts.tv_sec = 2;
                }
        }
        if (!error) {
                *statep |= NFSSTA_SNDLOCK;
        }
        lck_mtx_unlock(&nmp->nm_lock);
        return error;
}

/*
 * Unlock the stream socket for others.
 */
void
nfs_sndunlock(struct nfsreq *req)
{
        struct nfsmount *nmp = req->r_nmp;
        int *statep, wake = 0;

        if (!nmp) {
                return;
        }
        lck_mtx_lock(&nmp->nm_lock);
        statep = &nmp->nm_state;
        if ((*statep & NFSSTA_SNDLOCK) == 0) {
                panic("nfs sndunlock");
        }
        *statep &= ~(NFSSTA_SNDLOCK | NFSSTA_SENDING);
        if (*statep & NFSSTA_WANTSND) {
                *statep &= ~NFSSTA_WANTSND;
                wake = 1;
        }
        lck_mtx_unlock(&nmp->nm_lock);
        if (wake) {
                wakeup(statep);
        }
}

int
nfs_aux_request(
        struct nfsmount *nmp,
        thread_t thd,
        struct sockaddr *saddr,
        socket_t so,
        int sotype,
        mbuf_t mreq,
        uint32_t xid,
        int bindresv,
        int timeo,
        struct nfsm_chain *nmrep)
{
        int error = 0, on = 1, try, sendat = 2, soproto, recv, optlen, restoreto = 0;
        socket_t newso = NULL;
        struct sockaddr_storage ss;
        struct timeval orig_rcvto, orig_sndto, tv = { .tv_sec = 1, .tv_usec = 0 };
        mbuf_t m, mrep = NULL;
        struct msghdr msg;
        uint32_t rxid = 0, reply = 0, reply_status, rejected_status;
        uint32_t verf_type, verf_len, accepted_status;
        size_t readlen, sentlen;
        struct nfs_rpc_record_state nrrs;

        if (!so) {
                /* create socket and set options */
                if (saddr->sa_family == AF_LOCAL) {
                        soproto = 0;
                } else {
                        soproto = (sotype == SOCK_DGRAM) ? IPPROTO_UDP : IPPROTO_TCP;
                }
                if ((error = sock_socket(saddr->sa_family, sotype, soproto, NULL, NULL, &newso))) {
                        goto nfsmout;
                }

                if (bindresv && saddr->sa_family != AF_LOCAL) {
                        int level = (saddr->sa_family == AF_INET) ? IPPROTO_IP : IPPROTO_IPV6;
                        int optname = (saddr->sa_family == AF_INET) ? IP_PORTRANGE : IPV6_PORTRANGE;
                        int portrange = IP_PORTRANGE_LOW;
                        error = sock_setsockopt(newso, level, optname, &portrange, sizeof(portrange));
                        nfsmout_if(error);
                        ss.ss_len = saddr->sa_len;
                        ss.ss_family = saddr->sa_family;
                        if (ss.ss_family == AF_INET) {
                                ((struct sockaddr_in*)&ss)->sin_addr.s_addr = INADDR_ANY;
                                ((struct sockaddr_in*)&ss)->sin_port = htons(0);
                        } else if (ss.ss_family == AF_INET6) {
                                ((struct sockaddr_in6*)&ss)->sin6_addr = in6addr_any;
                                ((struct sockaddr_in6*)&ss)->sin6_port = htons(0);
                        } else {
                                error = EINVAL;
                        }
                        if (!error) {
                                error = sock_bind(newso, (struct sockaddr *)&ss);
                        }
                        nfsmout_if(error);
                }

                if (sotype == SOCK_STREAM) {
#                       define NFS_AUX_CONNECTION_TIMEOUT 4   /* 4 second timeout for connections */
                        int count = 0;

                        error = sock_connect(newso, saddr, MSG_DONTWAIT);
                        if (error == EINPROGRESS) {
                                error = 0;
                        }
                        nfsmout_if(error);

                        while ((error = sock_connectwait(newso, &tv)) == EINPROGRESS) {
                                /* After NFS_AUX_CONNECTION_TIMEOUT bail */
                                if (++count >= NFS_AUX_CONNECTION_TIMEOUT) {
                                        error = ETIMEDOUT;
                                        break;
                                }
                        }
                        nfsmout_if(error);
                }
                if (((error = sock_setsockopt(newso, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))) ||
                    ((error = sock_setsockopt(newso, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))) ||
                    ((error = sock_setsockopt(newso, SOL_SOCKET, SO_NOADDRERR, &on, sizeof(on))))) {
                        goto nfsmout;
                }
                so = newso;
        } else {
                /* make sure socket is using a one second timeout in this function */
                optlen = sizeof(orig_rcvto);
                error = sock_getsockopt(so, SOL_SOCKET, SO_RCVTIMEO, &orig_rcvto, &optlen);
                if (!error) {
                        optlen = sizeof(orig_sndto);
                        error = sock_getsockopt(so, SOL_SOCKET, SO_SNDTIMEO, &orig_sndto, &optlen);
                }
                if (!error) {
                        sock_setsockopt(so, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
                        sock_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
                        restoreto = 1;
                }
        }

        if (sotype == SOCK_STREAM) {
                sendat = 0; /* we only resend the request for UDP */
                nfs_rpc_record_state_init(&nrrs);
        }

        for (try = 0; try < timeo; try++) {
                if ((error = nfs_sigintr(nmp, NULL, !try ? NULL : thd, 0))) {
                        break;
                }
                if (!try || (try == sendat)) {
                        /* send the request (resending periodically for UDP) */
                        if ((error = mbuf_copym(mreq, 0, MBUF_COPYALL, MBUF_WAITOK, &m))) {
                                goto nfsmout;
                        }
                        bzero(&msg, sizeof(msg));
                        if ((sotype == SOCK_DGRAM) && !sock_isconnected(so)) {
                                msg.msg_name = saddr;
                                msg.msg_namelen = saddr->sa_len;
                        }
                        if ((error = sock_sendmbuf(so, &msg, m, 0, &sentlen))) {
                                goto nfsmout;
                        }
                        sendat *= 2;
                        if (sendat > 30) {
                                sendat = 30;
                        }
                }
                /* wait for the response */
                if (sotype == SOCK_STREAM) {
                        /* try to read (more of) record */
                        error = nfs_rpc_record_read(so, &nrrs, 0, &recv, &mrep);
                        /* if we don't have the whole record yet, we'll keep trying */
                } else {
                        readlen = 1 << 18;
                        bzero(&msg, sizeof(msg));
                        error = sock_receivembuf(so, &msg, &mrep, 0, &readlen);
                }
                if (error == EWOULDBLOCK) {
                        continue;
                }
                nfsmout_if(error);
                /* parse the response */
                nfsm_chain_dissect_init(error, nmrep, mrep);
                nfsm_chain_get_32(error, nmrep, rxid);
                nfsm_chain_get_32(error, nmrep, reply);
                nfsmout_if(error);
                if ((rxid != xid) || (reply != RPC_REPLY)) {
                        error = EBADRPC;
                }
                nfsm_chain_get_32(error, nmrep, reply_status);
                nfsmout_if(error);
                if (reply_status == RPC_MSGDENIED) {
                        nfsm_chain_get_32(error, nmrep, rejected_status);
                        nfsmout_if(error);
                        error = (rejected_status == RPC_MISMATCH) ? ERPCMISMATCH : EACCES;
                        goto nfsmout;
                }
                nfsm_chain_get_32(error, nmrep, verf_type); /* verifier flavor */
                nfsm_chain_get_32(error, nmrep, verf_len); /* verifier length */
                nfsmout_if(error);
                if (verf_len) {
                        nfsm_chain_adv(error, nmrep, nfsm_rndup(verf_len));
                }
                nfsm_chain_get_32(error, nmrep, accepted_status);
                nfsmout_if(error);
                switch (accepted_status) {
                case RPC_SUCCESS:
                        error = 0;
                        break;
                case RPC_PROGUNAVAIL:
                        error = EPROGUNAVAIL;
                        break;
                case RPC_PROGMISMATCH:
                        error = EPROGMISMATCH;
                        break;
                case RPC_PROCUNAVAIL:
                        error = EPROCUNAVAIL;
                        break;
                case RPC_GARBAGE:
                        error = EBADRPC;
                        break;
                case RPC_SYSTEM_ERR:
                default:
                        error = EIO;
                        break;
                }
                break;
        }
nfsmout:
        if (restoreto) {
                sock_setsockopt(so, SOL_SOCKET, SO_RCVTIMEO, &orig_rcvto, sizeof(tv));
                sock_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO, &orig_sndto, sizeof(tv));
        }
        if (newso) {
                sock_shutdown(newso, SHUT_RDWR);
                sock_close(newso);
        }
        mbuf_freem(mreq);
        return error;
}

int
nfs_portmap_lookup(
        struct nfsmount *nmp,
        vfs_context_t ctx,
        struct sockaddr *sa,
        socket_t so,
        uint32_t protocol,
        uint32_t vers,
        uint32_t stype,
        int timeo)
{
        thread_t thd = vfs_context_thread(ctx);
        kauth_cred_t cred = vfs_context_ucred(ctx);
        struct sockaddr_storage ss;
        struct sockaddr *saddr = (struct sockaddr*)&ss;
        static struct sockaddr_un rpcbind_cots = {
                sizeof(struct sockaddr_un),
                AF_LOCAL,
                RPCB_TICOTSORD_PATH
        };
        static struct sockaddr_un rpcbind_clts = {
                sizeof(struct sockaddr_un),
                AF_LOCAL,
                RPCB_TICLTS_PATH
        };
        struct nfsm_chain nmreq, nmrep;
        mbuf_t mreq;
        int error = 0, ip, pmprog, pmvers, pmproc;
        uint32_t ualen = 0;
        uint32_t port;
        uint64_t xid = 0;
        char uaddr[MAX_IPv6_STR_LEN + 16];

        bcopy(sa, saddr, min(sizeof(ss), sa->sa_len));
        if (saddr->sa_family == AF_INET) {
                ip = 4;
                pmprog = PMAPPROG;
                pmvers = PMAPVERS;
                pmproc = PMAPPROC_GETPORT;
        } else if (saddr->sa_family == AF_INET6) {
                ip = 6;
                pmprog = RPCBPROG;
                pmvers = RPCBVERS4;
                pmproc = RPCBPROC_GETVERSADDR;
        } else if (saddr->sa_family == AF_LOCAL) {
                ip = 0;
                pmprog = RPCBPROG;
                pmvers = RPCBVERS4;
                pmproc = RPCBPROC_GETVERSADDR;
                NFS_SOCK_DBG("%s\n", ((struct sockaddr_un*)sa)->sun_path);
                saddr = (struct sockaddr*)((stype == SOCK_STREAM) ? &rpcbind_cots : &rpcbind_clts);
        } else {
                return EINVAL;
        }
        nfsm_chain_null(&nmreq);
        nfsm_chain_null(&nmrep);

tryagain:
        /* send portmapper request to get port/uaddr */
        if (ip == 4) {
                ((struct sockaddr_in*)saddr)->sin_port = htons(PMAPPORT);
        } else if (ip == 6) {
                ((struct sockaddr_in6*)saddr)->sin6_port = htons(PMAPPORT);
        }
        nfsm_chain_build_alloc_init(error, &nmreq, 8 * NFSX_UNSIGNED);
        nfsm_chain_add_32(error, &nmreq, protocol);
        nfsm_chain_add_32(error, &nmreq, vers);
        if (ip == 4) {
                nfsm_chain_add_32(error, &nmreq, stype == SOCK_STREAM ? IPPROTO_TCP : IPPROTO_UDP);
                nfsm_chain_add_32(error, &nmreq, 0);
        } else {
                if (stype == SOCK_STREAM) {
                        if (ip == 6) {
                                nfsm_chain_add_string(error, &nmreq, "tcp6", 4);
                        } else {
                                nfsm_chain_add_string(error, &nmreq, "ticotsord", 9);
                        }
                } else {
                        if (ip == 6) {
                                nfsm_chain_add_string(error, &nmreq, "udp6", 4);
                        } else {
                                nfsm_chain_add_string(error, &nmreq, "ticlts", 6);
                        }
                }
                nfsm_chain_add_string(error, &nmreq, "", 0); /* uaddr */
                nfsm_chain_add_string(error, &nmreq, "", 0); /* owner */
        }
        nfsm_chain_build_done(error, &nmreq);
        nfsmout_if(error);
        error = nfsm_rpchead2(nmp, stype, pmprog, pmvers, pmproc,
            RPCAUTH_SYS, cred, NULL, nmreq.nmc_mhead, &xid, &mreq);
        nfsmout_if(error);
        nmreq.nmc_mhead = NULL;

        NFS_SOCK_DUMP_MBUF("nfs_portmap_loockup request", mreq);
        error = nfs_aux_request(nmp, thd, saddr, so,
            stype, mreq, R_XID32(xid), 0, timeo, &nmrep);
        NFS_SOCK_DUMP_MBUF("nfs_portmap_lookup reply", nmrep.nmc_mhead);
        NFS_SOCK_DBG("rpcbind request returned %d for program %u vers %u: %s\n", error, protocol, vers,
            (saddr->sa_family == AF_LOCAL) ? ((struct sockaddr_un *)saddr)->sun_path :
            (saddr->sa_family == AF_INET6) ? "INET6 socket" : "INET socket");

        /* grab port from portmap response */
        if (ip == 4) {
                nfsm_chain_get_32(error, &nmrep, port);
                if (!error) {
                        ((struct sockaddr_in*)sa)->sin_port = htons(port);
                }
        } else {
                /* get uaddr string and convert to sockaddr */
                nfsm_chain_get_32(error, &nmrep, ualen);
                if (!error) {
                        if (ualen > (sizeof(uaddr) - 1)) {
                                error = EIO;
                        }
                        if (ualen < 1) {
                                /* program is not available, just return a zero port */
                                bcopy(sa, saddr, min(sizeof(ss), sa->sa_len));
                                if (ip == 6) {
                                        ((struct sockaddr_in6*)saddr)->sin6_port = htons(0);
                                } else {
                                        ((struct sockaddr_un*)saddr)->sun_path[0] = '\0';
                                }
                                NFS_SOCK_DBG("Program %u version %u unavailable", protocol, vers);
                        } else {
                                nfsm_chain_get_opaque(error, &nmrep, ualen, uaddr);
                                NFS_SOCK_DBG("Got uaddr %s\n", uaddr);
                                if (!error) {
                                        uaddr[ualen] = '\0';
                                        if (!nfs_uaddr2sockaddr(uaddr, saddr)) {
                                                error = EIO;
                                        }
                                }
                        }
                }
                if ((error == EPROGMISMATCH) || (error == EPROCUNAVAIL) || (error == EIO) || (error == EBADRPC)) {
                        /* remote doesn't support rpcbind version or proc (or we couldn't parse uaddr) */
                        if (pmvers == RPCBVERS4) {
                                /* fall back to v3 and GETADDR */
                                pmvers = RPCBVERS3;
                                pmproc = RPCBPROC_GETADDR;
                                nfsm_chain_cleanup(&nmreq);
                                nfsm_chain_cleanup(&nmrep);
                                bcopy(sa, saddr, min(sizeof(ss), sa->sa_len));
                                xid = 0;
                                error = 0;
                                goto tryagain;
                        }
                }
                if (!error) {
                        bcopy(saddr, sa, min(saddr->sa_len, sa->sa_len));
                }
        }
nfsmout:
        nfsm_chain_cleanup(&nmreq);
        nfsm_chain_cleanup(&nmrep);
        NFS_SOCK_DBG("Returned %d\n", error);

        return error;
}

int
nfs_msg(thread_t thd,
    const char *server,
    const char *msg,
    int error)
{
        proc_t p = thd ? get_bsdthreadtask_info(thd) : NULL;
        tpr_t tpr;

        if (p) {
                tpr = tprintf_open(p);
        } else {
                tpr = NULL;
        }
        if (error) {
                tprintf(tpr, "nfs server %s: %s, error %d\n", server, msg, error);
        } else {
                tprintf(tpr, "nfs server %s: %s\n", server, msg);
        }
        tprintf_close(tpr);
        return 0;
}

#define NFS_SQUISH_MOBILE_ONLY          0x0001          /* Squish mounts only on mobile machines */
#define NFS_SQUISH_AUTOMOUNTED_ONLY     0x0002          /* Squish mounts only if the are automounted */
#define NFS_SQUISH_SOFT                 0x0004          /* Treat all soft mounts as though they were on a mobile machine */
#define NFS_SQUISH_QUICK                0x0008          /* Try to squish mounts more quickly. */
#define NFS_SQUISH_SHUTDOWN             0x1000          /* Squish all mounts on shutdown. Currently not implemented */

uint32_t nfs_squishy_flags = NFS_SQUISH_MOBILE_ONLY | NFS_SQUISH_AUTOMOUNTED_ONLY | NFS_SQUISH_QUICK;
int32_t nfs_is_mobile;

#define NFS_SQUISHY_DEADTIMEOUT         8       /* Dead time out for squishy mounts */
#define NFS_SQUISHY_QUICKTIMEOUT        4       /* Quicker dead time out when nfs_squish_flags NFS_SQUISH_QUICK bit is set*/

/*
 * Could this mount be squished?
 */
int
nfs_can_squish(struct nfsmount *nmp)
{
        uint64_t flags = vfs_flags(nmp->nm_mountp);
        int softsquish = ((nfs_squishy_flags & NFS_SQUISH_SOFT) & NMFLAG(nmp, SOFT));

        if (!softsquish && (nfs_squishy_flags & NFS_SQUISH_MOBILE_ONLY) && nfs_is_mobile == 0) {
                return 0;
        }

        if ((nfs_squishy_flags & NFS_SQUISH_AUTOMOUNTED_ONLY) && (flags & MNT_AUTOMOUNTED) == 0) {
                return 0;
        }

        return 1;
}

/*
 * NFS mounts default to "rw,hard" - but frequently on mobile clients
 * the mount may become "not responding".  It's desirable to be able
 * to unmount these dead mounts, but only if there is no risk of
 * losing data or crashing applications.  A "squishy" NFS mount is one
 * that can be force unmounted with little risk of harm.
 *
 * nfs_is_squishy checks if a mount is in a squishy state.  A mount is
 * in a squishy state iff it is allowed to be squishy and there are no
 * dirty pages and there are no mmapped files and there are no files
 * open for write. Mounts are allowed to be squishy is controlled by
 * the settings of the nfs_squishy_flags and its mobility state. These
 * flags can be set by sysctls.
 *
 * If nfs_is_squishy determines that we are in a squishy state we will
 * update the current dead timeout to at least NFS_SQUISHY_DEADTIMEOUT
 * (or NFS_SQUISHY_QUICKTIMEOUT if NFS_SQUISH_QUICK is set) (see
 * above) or 1/8th of the mount's nm_deadtimeout value, otherwise we just
 * update the current dead timeout with the mount's nm_deadtimeout
 * value set at mount time.
 *
 * Assumes that nm_lock is held.
 *
 * Note this routine is racey, but its effects on setting the
 * dead timeout only have effects when we're in trouble and are likely
 * to stay that way. Since by default its only for automounted
 * volumes on mobile machines; this is a reasonable trade off between
 * data integrity and user experience. It can be disabled or set via
 * nfs.conf file.
 */

int
nfs_is_squishy(struct nfsmount *nmp)
{
        mount_t mp = nmp->nm_mountp;
        int squishy = 0;
        int timeo = (nfs_squishy_flags & NFS_SQUISH_QUICK) ? NFS_SQUISHY_QUICKTIMEOUT : NFS_SQUISHY_DEADTIMEOUT;

        NFS_SOCK_DBG("%s: nm_curdeadtimeout = %d, nfs_is_mobile = %d\n",
            vfs_statfs(mp)->f_mntfromname, nmp->nm_curdeadtimeout, nfs_is_mobile);

        if (!nfs_can_squish(nmp)) {
                goto out;
        }

        timeo =  (nmp->nm_deadtimeout > timeo) ? max(nmp->nm_deadtimeout / 8, timeo) : timeo;
        NFS_SOCK_DBG("nm_writers = %d  nm_mappers = %d timeo = %d\n", nmp->nm_writers, nmp->nm_mappers, timeo);

        if (nmp->nm_writers == 0 && nmp->nm_mappers == 0) {
                uint64_t flags = mp ? vfs_flags(mp) : 0;
                squishy = 1;

                /*
                 * Walk the nfs nodes and check for dirty buffers it we're not
                 * RDONLY and we've not already been declared as squishy since
                 * this can be a bit expensive.
                 */
                if (!(flags & MNT_RDONLY) && !(nmp->nm_state & NFSSTA_SQUISHY)) {
                        squishy = !nfs_mount_is_dirty(mp);
                }
        }

out:
        if (squishy) {
                nmp->nm_state |= NFSSTA_SQUISHY;
        } else {
                nmp->nm_state &= ~NFSSTA_SQUISHY;
        }

        nmp->nm_curdeadtimeout = squishy ? timeo : nmp->nm_deadtimeout;

        NFS_SOCK_DBG("nm_curdeadtimeout = %d\n", nmp->nm_curdeadtimeout);

        return squishy;
}

/*
 * On a send operation, if we can't reach the server and we've got only one server to talk to
 * and NFS_SQUISH_QUICK flag is set and we are in a squishy state then mark the mount as dead
 * and ask to be forcibly unmounted. Return 1 if we're dead and 0 otherwise.
 */
int
nfs_is_dead(int error, struct nfsmount *nmp)
{
        fsid_t fsid;

        lck_mtx_lock(&nmp->nm_lock);
        if (nmp->nm_state & NFSSTA_DEAD) {
                lck_mtx_unlock(&nmp->nm_lock);
                return 1;
        }

        if ((error != ENETUNREACH && error != EHOSTUNREACH && error != EADDRNOTAVAIL) ||
            !(nmp->nm_locations.nl_numlocs == 1 && nmp->nm_locations.nl_locations[0]->nl_servcount == 1)) {
                lck_mtx_unlock(&nmp->nm_lock);
                return 0;
        }

        if ((nfs_squishy_flags & NFS_SQUISH_QUICK) && nfs_is_squishy(nmp)) {
                printf("nfs_is_dead: nfs server %s: unreachable. Squished dead\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname);
                fsid = vfs_statfs(nmp->nm_mountp)->f_fsid;
                lck_mtx_unlock(&nmp->nm_lock);
                nfs_mount_zombie(nmp, NFSSTA_DEAD);
                vfs_event_signal(&fsid, VQ_DEAD, 0);
                return 1;
        }
        lck_mtx_unlock(&nmp->nm_lock);
        return 0;
}

/*
 * If we've experienced timeouts and we're not really a
 * classic hard mount, then just return cached data to
 * the caller instead of likely hanging on an RPC.
 */
int
nfs_use_cache(struct nfsmount *nmp)
{
        /*
         *%%% We always let mobile users goto the cache,
         * perhaps we should not even require them to have
         * a timeout?
         */
        int cache_ok = (nfs_is_mobile || NMFLAG(nmp, SOFT) ||
            nfs_can_squish(nmp) || nmp->nm_deadtimeout);

        int timeoutmask = NFSSTA_TIMEO | NFSSTA_LOCKTIMEO | NFSSTA_JUKEBOXTIMEO;

        /*
         * So if we have a timeout and we're not really a hard hard-mount,
         * return 1 to not get things out of the cache.
         */

        return (nmp->nm_state & timeoutmask) && cache_ok;
}

/*
 * Log a message that nfs or lockd server is unresponsive. Check if we
 * can be squished and if we can, or that our dead timeout has
 * expired, and we're not holding state, set our mount as dead, remove
 * our mount state and ask to be unmounted. If we are holding state
 * we're being called from the nfs_request_timer and will soon detect
 * that we need to unmount.
 */
void
nfs_down(struct nfsmount *nmp, thread_t thd, int error, int flags, const char *msg, int holding_state)
{
        int timeoutmask, wasunresponsive, unresponsive, softnobrowse;
        uint32_t do_vfs_signal = 0;
        struct timeval now;

        if (nfs_mount_gone(nmp)) {
                return;
        }

        lck_mtx_lock(&nmp->nm_lock);

        timeoutmask = NFSSTA_TIMEO | NFSSTA_LOCKTIMEO | NFSSTA_JUKEBOXTIMEO;
        if (NMFLAG(nmp, MUTEJUKEBOX)) { /* jukebox timeouts don't count as unresponsive if muted */
                timeoutmask &= ~NFSSTA_JUKEBOXTIMEO;
        }
        wasunresponsive = (nmp->nm_state & timeoutmask);

        /* XXX don't allow users to know about/disconnect unresponsive, soft, nobrowse mounts */
        softnobrowse = (NMFLAG(nmp, SOFT) && (vfs_flags(nmp->nm_mountp) & MNT_DONTBROWSE));

        if ((flags & NFSSTA_TIMEO) && !(nmp->nm_state & NFSSTA_TIMEO)) {
                nmp->nm_state |= NFSSTA_TIMEO;
        }
        if ((flags & NFSSTA_LOCKTIMEO) && !(nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                nmp->nm_state |= NFSSTA_LOCKTIMEO;
        }
        if ((flags & NFSSTA_JUKEBOXTIMEO) && !(nmp->nm_state & NFSSTA_JUKEBOXTIMEO)) {
                nmp->nm_state |= NFSSTA_JUKEBOXTIMEO;
        }

        unresponsive = (nmp->nm_state & timeoutmask);

        nfs_is_squishy(nmp);

        if (unresponsive && (nmp->nm_curdeadtimeout > 0)) {
                microuptime(&now);
                if (!wasunresponsive) {
                        nmp->nm_deadto_start = now.tv_sec;
                        nfs_mount_sock_thread_wake(nmp);
                } else if ((now.tv_sec - nmp->nm_deadto_start) > nmp->nm_curdeadtimeout && !holding_state) {
                        if (!(nmp->nm_state & NFSSTA_DEAD)) {
                                printf("nfs server %s: %sdead\n", vfs_statfs(nmp->nm_mountp)->f_mntfromname,
                                    (nmp->nm_curdeadtimeout != nmp->nm_deadtimeout) ? "squished " : "");
                        }
                        do_vfs_signal = VQ_DEAD;
                }
        }
        lck_mtx_unlock(&nmp->nm_lock);

        if (do_vfs_signal == VQ_DEAD && !(nmp->nm_state & NFSSTA_DEAD)) {
                nfs_mount_zombie(nmp, NFSSTA_DEAD);
        } else if (softnobrowse || wasunresponsive || !unresponsive) {
                do_vfs_signal = 0;
        } else {
                do_vfs_signal = VQ_NOTRESP;
        }
        if (do_vfs_signal) {
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, do_vfs_signal, 0);
        }

        nfs_msg(thd, vfs_statfs(nmp->nm_mountp)->f_mntfromname, msg, error);
}

void
nfs_up(struct nfsmount *nmp, thread_t thd, int flags, const char *msg)
{
        int timeoutmask, wasunresponsive, unresponsive, softnobrowse;
        int do_vfs_signal;

        if (nfs_mount_gone(nmp)) {
                return;
        }

        if (msg) {
                nfs_msg(thd, vfs_statfs(nmp->nm_mountp)->f_mntfromname, msg, 0);
        }

        lck_mtx_lock(&nmp->nm_lock);

        timeoutmask = NFSSTA_TIMEO | NFSSTA_LOCKTIMEO | NFSSTA_JUKEBOXTIMEO;
        if (NMFLAG(nmp, MUTEJUKEBOX)) { /* jukebox timeouts don't count as unresponsive if muted */
                timeoutmask &= ~NFSSTA_JUKEBOXTIMEO;
        }
        wasunresponsive = (nmp->nm_state & timeoutmask);

        /* XXX don't allow users to know about/disconnect unresponsive, soft, nobrowse mounts */
        softnobrowse = (NMFLAG(nmp, SOFT) && (vfs_flags(nmp->nm_mountp) & MNT_DONTBROWSE));

        if ((flags & NFSSTA_TIMEO) && (nmp->nm_state & NFSSTA_TIMEO)) {
                nmp->nm_state &= ~NFSSTA_TIMEO;
        }
        if ((flags & NFSSTA_LOCKTIMEO) && (nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                nmp->nm_state &= ~NFSSTA_LOCKTIMEO;
        }
        if ((flags & NFSSTA_JUKEBOXTIMEO) && (nmp->nm_state & NFSSTA_JUKEBOXTIMEO)) {
                nmp->nm_state &= ~NFSSTA_JUKEBOXTIMEO;
        }

        unresponsive = (nmp->nm_state & timeoutmask);

        nmp->nm_deadto_start = 0;
        nmp->nm_curdeadtimeout = nmp->nm_deadtimeout;
        nmp->nm_state &= ~NFSSTA_SQUISHY;
        lck_mtx_unlock(&nmp->nm_lock);

        if (softnobrowse) {
                do_vfs_signal = 0;
        } else {
                do_vfs_signal = (wasunresponsive && !unresponsive);
        }
        if (do_vfs_signal) {
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, VQ_NOTRESP, 1);
        }
}


#endif /* NFSCLIENT */

#if NFSSERVER

/*
 * Generate the rpc reply header
 * siz arg. is used to decide if adding a cluster is worthwhile
 */
int
nfsrv_rephead(
        struct nfsrv_descript *nd,
        __unused struct nfsrv_sock *slp,
        struct nfsm_chain *nmrepp,
        size_t siz)
{
        mbuf_t mrep;
        u_int32_t *tl;
        struct nfsm_chain nmrep;
        int err, error;

        err = nd->nd_repstat;
        if (err && (nd->nd_vers == NFS_VER2)) {
                siz = 0;
        }

        /*
         * If this is a big reply, use a cluster else
         * try and leave leading space for the lower level headers.
         */
        siz += RPC_REPLYSIZ;
        if (siz >= nfs_mbuf_minclsize) {
                error = mbuf_getpacket(MBUF_WAITOK, &mrep);
        } else {
                error = mbuf_gethdr(MBUF_WAITOK, MBUF_TYPE_DATA, &mrep);
        }
        if (error) {
                /* unable to allocate packet */
                /* XXX should we keep statistics for these errors? */
                return error;
        }
        if (siz < nfs_mbuf_minclsize) {
                /* leave space for lower level headers */
                tl = mbuf_data(mrep);
                tl += 80 / sizeof(*tl);  /* XXX max_hdr? XXX */
                mbuf_setdata(mrep, tl, 6 * NFSX_UNSIGNED);
        }
        nfsm_chain_init(&nmrep, mrep);
        nfsm_chain_add_32(error, &nmrep, nd->nd_retxid);
        nfsm_chain_add_32(error, &nmrep, RPC_REPLY);
        if (err == ERPCMISMATCH || (err & NFSERR_AUTHERR)) {
                nfsm_chain_add_32(error, &nmrep, RPC_MSGDENIED);
                if (err & NFSERR_AUTHERR) {
                        nfsm_chain_add_32(error, &nmrep, RPC_AUTHERR);
                        nfsm_chain_add_32(error, &nmrep, (err & ~NFSERR_AUTHERR));
                } else {
                        nfsm_chain_add_32(error, &nmrep, RPC_MISMATCH);
                        nfsm_chain_add_32(error, &nmrep, RPC_VER2);
                        nfsm_chain_add_32(error, &nmrep, RPC_VER2);
                }
        } else {
                /* reply status */
                nfsm_chain_add_32(error, &nmrep, RPC_MSGACCEPTED);
                if (nd->nd_gss_context != NULL) {
                        /* RPCSEC_GSS verifier */
                        error = nfs_gss_svc_verf_put(nd, &nmrep);
                        if (error) {
                                nfsm_chain_add_32(error, &nmrep, RPC_SYSTEM_ERR);
                                goto done;
                        }
                } else {
                        /* RPCAUTH_NULL verifier */
                        nfsm_chain_add_32(error, &nmrep, RPCAUTH_NULL);
                        nfsm_chain_add_32(error, &nmrep, 0);
                }
                /* accepted status */
                switch (err) {
                case EPROGUNAVAIL:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROGUNAVAIL);
                        break;
                case EPROGMISMATCH:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROGMISMATCH);
                        /* XXX hard coded versions? */
                        nfsm_chain_add_32(error, &nmrep, NFS_VER2);
                        nfsm_chain_add_32(error, &nmrep, NFS_VER3);
                        break;
                case EPROCUNAVAIL:
                        nfsm_chain_add_32(error, &nmrep, RPC_PROCUNAVAIL);
                        break;
                case EBADRPC:
                        nfsm_chain_add_32(error, &nmrep, RPC_GARBAGE);
                        break;
                default:
                        nfsm_chain_add_32(error, &nmrep, RPC_SUCCESS);
                        if (nd->nd_gss_context != NULL) {
                                error = nfs_gss_svc_prepare_reply(nd, &nmrep);
                        }
                        if (err != NFSERR_RETVOID) {
                                nfsm_chain_add_32(error, &nmrep,
                                    (err ? nfsrv_errmap(nd, err) : 0));
                        }
                        break;
                }
        }

done:
        nfsm_chain_build_done(error, &nmrep);
        if (error) {
                /* error composing reply header */
                /* XXX should we keep statistics for these errors? */
                mbuf_freem(mrep);
                return error;
        }

        *nmrepp = nmrep;
        if ((err != 0) && (err != NFSERR_RETVOID)) {
                OSAddAtomic64(1, &nfsstats.srvrpc_errs);
        }
        return 0;
}

/*
 * The nfs server send routine.
 *
 * - return EINTR or ERESTART if interrupted by a signal
 * - return EPIPE if a connection is lost for connection based sockets (TCP...)
 * - do any cleanup required by recoverable socket errors (???)
 */
int
nfsrv_send(struct nfsrv_sock *slp, mbuf_t nam, mbuf_t top)
{
        int error;
        socket_t so = slp->ns_so;
        struct sockaddr *sendnam;
        struct msghdr msg;

        bzero(&msg, sizeof(msg));
        if (nam && !sock_isconnected(so) && (slp->ns_sotype != SOCK_STREAM)) {
                if ((sendnam = mbuf_data(nam))) {
                        msg.msg_name = (caddr_t)sendnam;
                        msg.msg_namelen = sendnam->sa_len;
                }
        }
        if (NFS_IS_DBG(NFS_FAC_SRV, 15)) {
                nfs_dump_mbuf(__func__, __LINE__, "nfsrv_send\n", top);
        }
        error = sock_sendmbuf(so, &msg, top, 0, NULL);
        if (!error) {
                return 0;
        }
        log(LOG_INFO, "nfsd send error %d\n", error);

        if ((error == EWOULDBLOCK) && (slp->ns_sotype == SOCK_STREAM)) {
                error = EPIPE;  /* zap TCP sockets if they time out on send */
        }
        /* Handle any recoverable (soft) socket errors here. (???) */
        if (error != EINTR && error != ERESTART && error != EIO &&
            error != EWOULDBLOCK && error != EPIPE) {
                error = 0;
        }

        return error;
}

/*
 * Socket upcall routine for the nfsd sockets.
 * The caddr_t arg is a pointer to the "struct nfsrv_sock".
 * Essentially do as much as possible non-blocking, else punt and it will
 * be called with MBUF_WAITOK from an nfsd.
 */
void
nfsrv_rcv(socket_t so, void *arg, int waitflag)
{
        struct nfsrv_sock *slp = arg;

        if (!nfsd_thread_count || !(slp->ns_flag & SLP_VALID)) {
                return;
        }

        lck_rw_lock_exclusive(&slp->ns_rwlock);
        nfsrv_rcv_locked(so, slp, waitflag);
        /* Note: ns_rwlock gets dropped when called with MBUF_DONTWAIT */
}
void
nfsrv_rcv_locked(socket_t so, struct nfsrv_sock *slp, int waitflag)
{
        mbuf_t m, mp, mhck, m2;
        int ns_flag = 0, error;
        struct msghdr   msg;
        size_t bytes_read;

        if ((slp->ns_flag & SLP_VALID) == 0) {
                if (waitflag == MBUF_DONTWAIT) {
                        lck_rw_done(&slp->ns_rwlock);
                }
                return;
        }

#ifdef notdef
        /*
         * Define this to test for nfsds handling this under heavy load.
         */
        if (waitflag == MBUF_DONTWAIT) {
                ns_flag = SLP_NEEDQ;
                goto dorecs;
        }
#endif
        if (slp->ns_sotype == SOCK_STREAM) {
                /*
                 * If there are already records on the queue, defer soreceive()
                 * to an(other) nfsd so that there is feedback to the TCP layer that
                 * the nfs servers are heavily loaded.
                 */
                if (slp->ns_rec) {
                        ns_flag = SLP_NEEDQ;
                        goto dorecs;
                }

                /*
                 * Do soreceive().
                 */
                bytes_read = 1000000000;
                error = sock_receivembuf(so, NULL, &mp, MSG_DONTWAIT, &bytes_read);
                if (error || mp == NULL) {
                        if (error == EWOULDBLOCK) {
                                ns_flag = (waitflag == MBUF_DONTWAIT) ? SLP_NEEDQ : 0;
                        } else {
                                ns_flag = SLP_DISCONN;
                        }
                        goto dorecs;
                }
                m = mp;
                if (slp->ns_rawend) {
                        if ((error = mbuf_setnext(slp->ns_rawend, m))) {
                                panic("nfsrv_rcv: mbuf_setnext failed %d\n", error);
                        }
                        slp->ns_cc += bytes_read;
                } else {
                        slp->ns_raw = m;
                        slp->ns_cc = bytes_read;
                }
                while ((m2 = mbuf_next(m))) {
                        m = m2;
                }
                slp->ns_rawend = m;

                /*
                 * Now try and parse record(s) out of the raw stream data.
                 */
                error = nfsrv_getstream(slp, waitflag);
                if (error) {
                        if (error == EPERM) {
                                ns_flag = SLP_DISCONN;
                        } else {
                                ns_flag = SLP_NEEDQ;
                        }
                }
        } else {
                struct sockaddr_storage nam;

                if (slp->ns_reccnt >= nfsrv_sock_max_rec_queue_length) {
                        /* already have max # RPC records queued on this socket */
                        ns_flag = SLP_NEEDQ;
                        goto dorecs;
                }

                bzero(&msg, sizeof(msg));
                msg.msg_name = (caddr_t)&nam;
                msg.msg_namelen = sizeof(nam);

                do {
                        bytes_read = 1000000000;
                        error = sock_receivembuf(so, &msg, &mp, MSG_DONTWAIT | MSG_NEEDSA, &bytes_read);
                        if (mp) {
                                if (msg.msg_name && (mbuf_get(MBUF_WAITOK, MBUF_TYPE_SONAME, &mhck) == 0)) {
                                        mbuf_setlen(mhck, nam.ss_len);
                                        bcopy(&nam, mbuf_data(mhck), nam.ss_len);
                                        m = mhck;
                                        if (mbuf_setnext(m, mp)) {
                                                /* trouble... just drop it */
                                                printf("nfsrv_rcv: mbuf_setnext failed\n");
                                                mbuf_free(mhck);
                                                m = mp;
                                        }
                                } else {
                                        m = mp;
                                }
                                if (slp->ns_recend) {
                                        mbuf_setnextpkt(slp->ns_recend, m);
                                } else {
                                        slp->ns_rec = m;
                                        slp->ns_flag |= SLP_DOREC;
                                }
                                slp->ns_recend = m;
                                mbuf_setnextpkt(m, NULL);
                                slp->ns_reccnt++;
                        }
                } while (mp);
        }

        /*
         * Now try and process the request records, non-blocking.
         */
dorecs:
        if (ns_flag) {
                slp->ns_flag |= ns_flag;
        }
        if (waitflag == MBUF_DONTWAIT) {
                int wake = (slp->ns_flag & SLP_WORKTODO);
                lck_rw_done(&slp->ns_rwlock);
                if (wake && nfsd_thread_count) {
                        lck_mtx_lock(nfsd_mutex);
                        nfsrv_wakenfsd(slp);
                        lck_mtx_unlock(nfsd_mutex);
                }
        }
}

/*
 * Try and extract an RPC request from the mbuf data list received on a
 * stream socket. The "waitflag" argument indicates whether or not it
 * can sleep.
 */
int
nfsrv_getstream(struct nfsrv_sock *slp, int waitflag)
{
        mbuf_t m;
        char *cp1, *cp2, *mdata;
        int len, mlen, error;
        mbuf_t om, m2, recm;
        u_int32_t recmark;

        if (slp->ns_flag & SLP_GETSTREAM) {
                panic("nfs getstream");
        }
        slp->ns_flag |= SLP_GETSTREAM;
        for (;;) {
                if (slp->ns_reclen == 0) {
                        if (slp->ns_cc < NFSX_UNSIGNED) {
                                slp->ns_flag &= ~SLP_GETSTREAM;
                                return 0;
                        }
                        m = slp->ns_raw;
                        mdata = mbuf_data(m);
                        mlen = mbuf_len(m);
                        if (mlen >= NFSX_UNSIGNED) {
                                bcopy(mdata, (caddr_t)&recmark, NFSX_UNSIGNED);
                                mdata += NFSX_UNSIGNED;
                                mlen -= NFSX_UNSIGNED;
                                mbuf_setdata(m, mdata, mlen);
                        } else {
                                cp1 = (caddr_t)&recmark;
                                cp2 = mdata;
                                while (cp1 < ((caddr_t)&recmark) + NFSX_UNSIGNED) {
                                        while (mlen == 0) {
                                                m = mbuf_next(m);
                                                cp2 = mbuf_data(m);
                                                mlen = mbuf_len(m);
                                        }
                                        *cp1++ = *cp2++;
                                        mlen--;
                                        mbuf_setdata(m, cp2, mlen);
                                }
                        }
                        slp->ns_cc -= NFSX_UNSIGNED;
                        recmark = ntohl(recmark);
                        slp->ns_reclen = recmark & ~0x80000000;
                        if (recmark & 0x80000000) {
                                slp->ns_flag |= SLP_LASTFRAG;
                        } else {
                                slp->ns_flag &= ~SLP_LASTFRAG;
                        }
                        if (slp->ns_reclen <= 0 || slp->ns_reclen > NFS_MAXPACKET) {
                                slp->ns_flag &= ~SLP_GETSTREAM;
                                return EPERM;
                        }
                }

                /*
                 * Now get the record part.
                 *
                 * Note that slp->ns_reclen may be 0.  Linux sometimes
                 * generates 0-length RPCs
                 */
                recm = NULL;
                if (slp->ns_cc == slp->ns_reclen) {
                        recm = slp->ns_raw;
                        slp->ns_raw = slp->ns_rawend = NULL;
                        slp->ns_cc = slp->ns_reclen = 0;
                } else if (slp->ns_cc > slp->ns_reclen) {
                        len = 0;
                        m = slp->ns_raw;
                        mlen = mbuf_len(m);
                        mdata = mbuf_data(m);
                        om = NULL;
                        while (len < slp->ns_reclen) {
                                if ((len + mlen) > slp->ns_reclen) {
                                        if (mbuf_copym(m, 0, slp->ns_reclen - len, waitflag, &m2)) {
                                                slp->ns_flag &= ~SLP_GETSTREAM;
                                                return EWOULDBLOCK;
                                        }
                                        if (om) {
                                                if (mbuf_setnext(om, m2)) {
                                                        /* trouble... just drop it */
                                                        printf("nfsrv_getstream: mbuf_setnext failed\n");
                                                        mbuf_freem(m2);
                                                        slp->ns_flag &= ~SLP_GETSTREAM;
                                                        return EWOULDBLOCK;
                                                }
                                                recm = slp->ns_raw;
                                        } else {
                                                recm = m2;
                                        }
                                        mdata += slp->ns_reclen - len;
                                        mlen -= slp->ns_reclen - len;
                                        mbuf_setdata(m, mdata, mlen);
                                        len = slp->ns_reclen;
                                } else if ((len + mlen) == slp->ns_reclen) {
                                        om = m;
                                        len += mlen;
                                        m = mbuf_next(m);
                                        recm = slp->ns_raw;
                                        if (mbuf_setnext(om, NULL)) {
                                                printf("nfsrv_getstream: mbuf_setnext failed 2\n");
                                                slp->ns_flag &= ~SLP_GETSTREAM;
                                                return EWOULDBLOCK;
                                        }
                                        mlen = mbuf_len(m);
                                        mdata = mbuf_data(m);
                                } else {
                                        om = m;
                                        len += mlen;
                                        m = mbuf_next(m);
                                        mlen = mbuf_len(m);
                                        mdata = mbuf_data(m);
                                }
                        }
                        slp->ns_raw = m;
                        slp->ns_cc -= len;
                        slp->ns_reclen = 0;
                } else {
                        slp->ns_flag &= ~SLP_GETSTREAM;
                        return 0;
                }

                /*
                 * Accumulate the fragments into a record.
                 */
                if (slp->ns_frag == NULL) {
                        slp->ns_frag = recm;
                } else {
                        m = slp->ns_frag;
                        while ((m2 = mbuf_next(m))) {
                                m = m2;
                        }
                        if ((error = mbuf_setnext(m, recm))) {
                                panic("nfsrv_getstream: mbuf_setnext failed 3, %d\n", error);
                        }
                }
                if (slp->ns_flag & SLP_LASTFRAG) {
                        if (slp->ns_recend) {
                                mbuf_setnextpkt(slp->ns_recend, slp->ns_frag);
                        } else {
                                slp->ns_rec = slp->ns_frag;
                                slp->ns_flag |= SLP_DOREC;
                        }
                        slp->ns_recend = slp->ns_frag;
                        slp->ns_frag = NULL;
                }
        }
}

/*
 * Parse an RPC header.
 */
int
nfsrv_dorec(
        struct nfsrv_sock *slp,
        struct nfsd *nfsd,
        struct nfsrv_descript **ndp)
{
        mbuf_t m;
        mbuf_t nam;
        struct nfsrv_descript *nd;
        int error = 0;

        *ndp = NULL;
        if (!(slp->ns_flag & (SLP_VALID | SLP_DOREC)) || (slp->ns_rec == NULL)) {
                return ENOBUFS;
        }
        MALLOC_ZONE(nd, struct nfsrv_descript *,
            sizeof(struct nfsrv_descript), M_NFSRVDESC, M_WAITOK);
        if (!nd) {
                return ENOMEM;
        }
        m = slp->ns_rec;
        slp->ns_rec = mbuf_nextpkt(m);
        if (slp->ns_rec) {
                mbuf_setnextpkt(m, NULL);
        } else {
                slp->ns_flag &= ~SLP_DOREC;
                slp->ns_recend = NULL;
        }
        slp->ns_reccnt--;
        if (mbuf_type(m) == MBUF_TYPE_SONAME) {
                nam = m;
                m = mbuf_next(m);
                if ((error = mbuf_setnext(nam, NULL))) {
                        panic("nfsrv_dorec: mbuf_setnext failed %d\n", error);
                }
        } else {
                nam = NULL;
        }
        nd->nd_nam2 = nam;
        nfsm_chain_dissect_init(error, &nd->nd_nmreq, m);
        if (!error) {
                error = nfsrv_getreq(nd);
        }
        if (error) {
                if (nam) {
                        mbuf_freem(nam);
                }
                if (nd->nd_gss_context) {
                        nfs_gss_svc_ctx_deref(nd->nd_gss_context);
                }
                FREE_ZONE(nd, sizeof(*nd), M_NFSRVDESC);
                return error;
        }
        nd->nd_mrep = NULL;
        *ndp = nd;
        nfsd->nfsd_nd = nd;
        return 0;
}

/*
 * Parse an RPC request
 * - verify it
 * - fill in the cred struct.
 */
int
nfsrv_getreq(struct nfsrv_descript *nd)
{
        struct nfsm_chain *nmreq;
        int len, i;
        u_int32_t nfsvers, auth_type;
        int error = 0;
        uid_t user_id;
        gid_t group_id;
        int ngroups;
        uint32_t val;

        nd->nd_cr = NULL;
        nd->nd_gss_context = NULL;
        nd->nd_gss_seqnum = 0;
        nd->nd_gss_mb = NULL;

        user_id = group_id = -2;
        val = auth_type = len = 0;

        nmreq = &nd->nd_nmreq;
        nfsm_chain_get_32(error, nmreq, nd->nd_retxid); // XID
        nfsm_chain_get_32(error, nmreq, val);           // RPC Call
        if (!error && (val != RPC_CALL)) {
                error = EBADRPC;
        }
        nfsmout_if(error);
        nd->nd_repstat = 0;
        nfsm_chain_get_32(error, nmreq, val);   // RPC Version
        nfsmout_if(error);
        if (val != RPC_VER2) {
                nd->nd_repstat = ERPCMISMATCH;
                nd->nd_procnum = NFSPROC_NOOP;
                return 0;
        }
        nfsm_chain_get_32(error, nmreq, val);   // RPC Program Number
        nfsmout_if(error);
        if (val != NFS_PROG) {
                nd->nd_repstat = EPROGUNAVAIL;
                nd->nd_procnum = NFSPROC_NOOP;
                return 0;
        }
        nfsm_chain_get_32(error, nmreq, nfsvers);// NFS Version Number
        nfsmout_if(error);
        if ((nfsvers < NFS_VER2) || (nfsvers > NFS_VER3)) {
                nd->nd_repstat = EPROGMISMATCH;
                nd->nd_procnum = NFSPROC_NOOP;
                return 0;
        }
        nd->nd_vers = nfsvers;
        nfsm_chain_get_32(error, nmreq, nd->nd_procnum);// NFS Procedure Number
        nfsmout_if(error);
        if ((nd->nd_procnum >= NFS_NPROCS) ||
            ((nd->nd_vers == NFS_VER2) && (nd->nd_procnum > NFSV2PROC_STATFS))) {
                nd->nd_repstat = EPROCUNAVAIL;
                nd->nd_procnum = NFSPROC_NOOP;
                return 0;
        }
        if (nfsvers != NFS_VER3) {
                nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
        }
        nfsm_chain_get_32(error, nmreq, auth_type);     // Auth Flavor
        nfsm_chain_get_32(error, nmreq, len);           // Auth Length
        if (!error && (len < 0 || len > RPCAUTH_MAXSIZ)) {
                error = EBADRPC;
        }
        nfsmout_if(error);

        /* Handle authentication */
        if (auth_type == RPCAUTH_SYS) {
                struct posix_cred temp_pcred;
                if (nd->nd_procnum == NFSPROC_NULL) {
                        return 0;
                }
                nd->nd_sec = RPCAUTH_SYS;
                nfsm_chain_adv(error, nmreq, NFSX_UNSIGNED);    // skip stamp
                nfsm_chain_get_32(error, nmreq, len);           // hostname length
                if (len < 0 || len > NFS_MAXNAMLEN) {
                        error = EBADRPC;
                }
                nfsm_chain_adv(error, nmreq, nfsm_rndup(len));  // skip hostname
                nfsmout_if(error);

                /* create a temporary credential using the bits from the wire */
                bzero(&temp_pcred, sizeof(temp_pcred));
                nfsm_chain_get_32(error, nmreq, user_id);
                nfsm_chain_get_32(error, nmreq, group_id);
                temp_pcred.cr_groups[0] = group_id;
                nfsm_chain_get_32(error, nmreq, len);           // extra GID count
                if ((len < 0) || (len > RPCAUTH_UNIXGIDS)) {
                        error = EBADRPC;
                }
                nfsmout_if(error);
                for (i = 1; i <= len; i++) {
                        if (i < NGROUPS) {
                                nfsm_chain_get_32(error, nmreq, temp_pcred.cr_groups[i]);
                        } else {
                                nfsm_chain_adv(error, nmreq, NFSX_UNSIGNED);
                        }
                }
                nfsmout_if(error);
                ngroups = (len >= NGROUPS) ? NGROUPS : (len + 1);
                if (ngroups > 1) {
                        nfsrv_group_sort(&temp_pcred.cr_groups[0], ngroups);
                }
                nfsm_chain_adv(error, nmreq, NFSX_UNSIGNED);    // verifier flavor (should be AUTH_NONE)
                nfsm_chain_get_32(error, nmreq, len);           // verifier length
                if (len < 0 || len > RPCAUTH_MAXSIZ) {
                        error = EBADRPC;
                }
                if (len > 0) {
                        nfsm_chain_adv(error, nmreq, nfsm_rndup(len));
                }

                /* request creation of a real credential */
                temp_pcred.cr_uid = user_id;
                temp_pcred.cr_ngroups = ngroups;
                nd->nd_cr = posix_cred_create(&temp_pcred);
                if (nd->nd_cr == NULL) {
                        nd->nd_repstat = ENOMEM;
                        nd->nd_procnum = NFSPROC_NOOP;
                        return 0;
                }
        } else if (auth_type == RPCSEC_GSS) {
                error = nfs_gss_svc_cred_get(nd, nmreq);
                if (error) {
                        if (error == EINVAL) {
                                goto nfsmout;   // drop the request
                        }
                        nd->nd_repstat = error;
                        nd->nd_procnum = NFSPROC_NOOP;
                        return 0;
                }
        } else {
                if (nd->nd_procnum == NFSPROC_NULL) {   // assume it's AUTH_NONE
                        return 0;
                }
                nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
                nd->nd_procnum = NFSPROC_NOOP;
                return 0;
        }
        return 0;
nfsmout:
        if (IS_VALID_CRED(nd->nd_cr)) {
                kauth_cred_unref(&nd->nd_cr);
        }
        nfsm_chain_cleanup(nmreq);
        return error;
}

/*
 * Search for a sleeping nfsd and wake it up.
 * SIDE EFFECT: If none found, make sure the socket is queued up so that one
 * of the running nfsds will go look for the work in the nfsrv_sockwait list.
 * Note: Must be called with nfsd_mutex held.
 */
void
nfsrv_wakenfsd(struct nfsrv_sock *slp)
{
        struct nfsd *nd;

        if ((slp->ns_flag & SLP_VALID) == 0) {
                return;
        }

        lck_rw_lock_exclusive(&slp->ns_rwlock);
        /* if there's work to do on this socket, make sure it's queued up */
        if ((slp->ns_flag & SLP_WORKTODO) && !(slp->ns_flag & SLP_QUEUED)) {
                TAILQ_INSERT_TAIL(&nfsrv_sockwait, slp, ns_svcq);
                slp->ns_flag |= SLP_WAITQ;
        }
        lck_rw_done(&slp->ns_rwlock);

        /* wake up a waiting nfsd, if possible */
        nd = TAILQ_FIRST(&nfsd_queue);
        if (!nd) {
                return;
        }

        TAILQ_REMOVE(&nfsd_queue, nd, nfsd_queue);
        nd->nfsd_flag &= ~NFSD_WAITING;
        wakeup(nd);
}

#endif /* NFSSERVER */