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

/*
 * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_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_LICENSE_OSREFERENCE_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/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/syslog.h>
#include <sys/tprintf.h>
#include <sys/uio_internal.h>
#include <libkern/OSAtomic.h>

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

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

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

#include <sys/kdebug.h>

#define FSDBG(A, B, C, D, E) \
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, (A))) | DBG_FUNC_NONE, \
                (int)(B), (int)(C), (int)(D), (int)(E), 0)
#define FSDBG_TOP(A, B, C, D, E) \
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, (A))) | DBG_FUNC_START, \
                (int)(B), (int)(C), (int)(D), (int)(E), 0)
#define FSDBG_BOT(A, B, C, D, E) \
        KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, (A))) | DBG_FUNC_END, \
                (int)(B), (int)(C), (int)(D), (int)(E), 0)

/*
 * 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]
/*
 * External data, mostly RPC constants in XDR form
 */
extern u_long rpc_reply, rpc_msgdenied, rpc_mismatch, rpc_vers, rpc_auth_unix,
        rpc_msgaccepted, rpc_call, rpc_autherr,
        rpc_auth_kerb;
extern u_long nfs_prog;
extern struct nfsstats nfsstats;
extern int nfsv3_procid[NFS_NPROCS];
extern int nfs_ticks;
extern u_long nfs_xidwrap;

/*
 * Defines which timer to use for the procnum.
 * 0 - default
 * 1 - getattr
 * 2 - lookup
 * 3 - read
 * 4 - write
 */
static int proct[NFS_NPROCS] = {
        0, 1, 0, 2, 1, 3, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 3, 3, 0, 0, 0, 0, 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, };
int nfsrtton = 0;
struct nfsrtt nfsrtt;

static int      nfs_rcvlock(struct nfsreq *);
static void     nfs_rcvunlock(struct nfsreq *);
static int      nfs_receive(struct nfsreq *rep, mbuf_t *mp);
static int      nfs_reconnect(struct nfsreq *rep);
static void     nfs_repdequeue(struct nfsreq *rep);

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

#ifndef NFS_NOSERVER 
static int      nfsrv_getstream(struct nfssvc_sock *,int);

int (*nfsrv3_procs[NFS_NPROCS])(struct nfsrv_descript *nd,
                                    struct nfssvc_sock *slp,
                                    proc_t procp,
                                    mbuf_t *mreqp) = {
        nfsrv_null,
        nfsrv_getattr,
        nfsrv_setattr,
        nfsrv_lookup,
        nfsrv3_access,
        nfsrv_readlink,
        nfsrv_read,
        nfsrv_write,
        nfsrv_create,
        nfsrv_mkdir,
        nfsrv_symlink,
        nfsrv_mknod,
        nfsrv_remove,
        nfsrv_rmdir,
        nfsrv_rename,
        nfsrv_link,
        nfsrv_readdir,
        nfsrv_readdirplus,
        nfsrv_statfs,
        nfsrv_fsinfo,
        nfsrv_pathconf,
        nfsrv_commit,
        nfsrv_noop
};
#endif /* NFS_NOSERVER */


/*
 * attempt to bind a socket to a reserved port
 */
static int
nfs_bind_resv(struct nfsmount *nmp)
{
        socket_t so = nmp->nm_so;
        struct sockaddr_in sin;
        int error;
        u_short tport;

        if (!so)
                return (EINVAL);

        sin.sin_len = sizeof (struct sockaddr_in);
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = INADDR_ANY;
        tport = IPPORT_RESERVED - 1;
        sin.sin_port = htons(tport);

        while (((error = sock_bind(so, (struct sockaddr *) &sin)) == EADDRINUSE) &&
               (--tport > IPPORT_RESERVED / 2))
                sin.sin_port = htons(tport);
        return (error);
}

/*
 * variables for managing the nfs_bind_resv_thread
 */
int nfs_resv_mounts = 0;
static int nfs_bind_resv_thread_state = 0;
#define NFS_BIND_RESV_THREAD_STATE_INITTED      1
#define NFS_BIND_RESV_THREAD_STATE_RUNNING      2
lck_grp_t *nfs_bind_resv_lck_grp;
lck_grp_attr_t *nfs_bind_resv_lck_grp_attr;
lck_attr_t *nfs_bind_resv_lck_attr;
lck_mtx_t *nfs_bind_resv_mutex;
struct nfs_bind_resv_request {
        TAILQ_ENTRY(nfs_bind_resv_request) brr_chain;
        struct nfsmount *brr_nmp;
        int brr_error;
};
static TAILQ_HEAD(, nfs_bind_resv_request) nfs_bind_resv_request_queue;

/*
 * thread to handle any reserved port bind requests
 */
static void
nfs_bind_resv_thread(void)
{
        struct nfs_bind_resv_request *brreq;

        nfs_bind_resv_thread_state = NFS_BIND_RESV_THREAD_STATE_RUNNING;

        while (nfs_resv_mounts > 0) {
                lck_mtx_lock(nfs_bind_resv_mutex);
                while ((brreq = TAILQ_FIRST(&nfs_bind_resv_request_queue))) {
                        TAILQ_REMOVE(&nfs_bind_resv_request_queue, brreq, brr_chain);
                        lck_mtx_unlock(nfs_bind_resv_mutex);
                        brreq->brr_error = nfs_bind_resv(brreq->brr_nmp);
                        wakeup(brreq);
                        lck_mtx_lock(nfs_bind_resv_mutex);
                }
                msleep((caddr_t)&nfs_bind_resv_request_queue,
                                nfs_bind_resv_mutex, PSOCK | PDROP,
                                "nfs_bind_resv_request_queue", 0);
        }

        nfs_bind_resv_thread_state = NFS_BIND_RESV_THREAD_STATE_INITTED;
        (void) thread_terminate(current_thread());
}

int
nfs_bind_resv_thread_wake(void)
{
        if (nfs_bind_resv_thread_state < NFS_BIND_RESV_THREAD_STATE_RUNNING)
                return (EIO);
        wakeup(&nfs_bind_resv_request_queue);
        return (0);
}

/*
 * underprivileged procs call this to request nfs_bind_resv_thread
 * to perform the reserved port binding for them.
 */
static int
nfs_bind_resv_nopriv(struct nfsmount *nmp)
{
        struct nfs_bind_resv_request brreq;
        int error;

        if (nfs_bind_resv_thread_state < NFS_BIND_RESV_THREAD_STATE_RUNNING) {
                if (nfs_bind_resv_thread_state < NFS_BIND_RESV_THREAD_STATE_INITTED) {
                        nfs_bind_resv_lck_grp_attr = lck_grp_attr_alloc_init();
                        nfs_bind_resv_lck_grp = lck_grp_alloc_init("nfs_bind_resv", nfs_bind_resv_lck_grp_attr);
                        nfs_bind_resv_lck_attr = lck_attr_alloc_init();
                        nfs_bind_resv_mutex = lck_mtx_alloc_init(nfs_bind_resv_lck_grp, nfs_bind_resv_lck_attr);
                        TAILQ_INIT(&nfs_bind_resv_request_queue);
                        nfs_bind_resv_thread_state = NFS_BIND_RESV_THREAD_STATE_INITTED;
                }
                kernel_thread(kernel_task, nfs_bind_resv_thread);
                nfs_bind_resv_thread_state = NFS_BIND_RESV_THREAD_STATE_RUNNING;
        }

        brreq.brr_nmp = nmp;
        brreq.brr_error = 0;

        lck_mtx_lock(nfs_bind_resv_mutex);
        TAILQ_INSERT_TAIL(&nfs_bind_resv_request_queue, &brreq, brr_chain);
        lck_mtx_unlock(nfs_bind_resv_mutex);

        error = nfs_bind_resv_thread_wake();
        if (error) {
                TAILQ_REMOVE(&nfs_bind_resv_request_queue, &brreq, brr_chain);
                /* Note: we might be able to simply restart the thread */
                return (error);
        }

        tsleep((caddr_t)&brreq, PSOCK, "nfsbindresv", 0);

        return (brreq.brr_error);
}

/*
 * Initialize sockets and congestion for a new NFS connection.
 * We do not free the sockaddr if error.
 */
int
nfs_connect(
        struct nfsmount *nmp,
        __unused struct nfsreq *rep)
{
        socket_t so;
        int error, rcvreserve, sndreserve;
        struct sockaddr *saddr;
        struct timeval timeo;

        nmp->nm_so = 0;
        saddr = mbuf_data(nmp->nm_nam);
        error = sock_socket(saddr->sa_family, nmp->nm_sotype,
                                                nmp->nm_soproto, 0, 0, &nmp->nm_so);
        if (error) {
                goto bad;
        }
        so = nmp->nm_so;

        /*
         * Some servers require that the client port be a reserved port number.
         */
        if (saddr->sa_family == AF_INET && (nmp->nm_flag & NFSMNT_RESVPORT)) {
                proc_t p;
                /*
                 * sobind() requires current_proc() to have superuser privs.
                 * If this bind is part of a reconnect, and the current proc
                 * doesn't have superuser privs, we hand the sobind() off to
                 * a kernel thread to process.
                 */
                if ((nmp->nm_state & NFSSTA_MOUNTED) &&
                    (p = current_proc()) && suser(kauth_cred_get(), 0)) {
                        /* request nfs_bind_resv_thread() to do bind */
                        error = nfs_bind_resv_nopriv(nmp);
                } else {
                        error = nfs_bind_resv(nmp);
                }
                if (error)
                        goto bad;
        }

        /*
         * Protocols that do not require connections may be optionally left
         * unconnected for servers that reply from a port other than NFS_PORT.
         */
        if (nmp->nm_flag & NFSMNT_NOCONN) {
                if (nmp->nm_sotype == SOCK_STREAM) {
                        error = ENOTCONN;
                        goto bad;
                }
        } else {
                struct timeval  tv;
                tv.tv_sec = 2;
                tv.tv_usec = 0;
                error = sock_connect(so, mbuf_data(nmp->nm_nam), MSG_DONTWAIT);
                if (error && error != EINPROGRESS) {
                        goto bad;
                }
                
                while ((error = sock_connectwait(so, &tv)) == EINPROGRESS) {
                        if (rep && (error = nfs_sigintr(nmp, rep, rep->r_procp))) {
                                goto bad;
                        }
                }
        }
        
        /*
         * Always time out on recieve, this allows us to reconnect the
         * socket to deal with network changes.
         */
        timeo.tv_usec = 0;
        timeo.tv_sec = 2;
        error = sock_setsockopt(so, SOL_SOCKET, SO_RCVTIMEO, &timeo, sizeof(timeo));
        if (nmp->nm_flag & (NFSMNT_SOFT | NFSMNT_INT)) {
                timeo.tv_sec = 5;
        } else {
                timeo.tv_sec = 0;
        }
        error = sock_setsockopt(so, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
        
        if (nmp->nm_sotype == SOCK_DGRAM) {
                sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR) * 3;
                rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR) *
                        (nmp->nm_readahead > 0 ? nmp->nm_readahead + 1 : 2);
        } else if (nmp->nm_sotype == SOCK_SEQPACKET) {
                sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR) * 3;
                rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR) *
                        (nmp->nm_readahead > 0 ? nmp->nm_readahead + 1 : 2);
        } else {
                int proto;
                int on = 1;
                
                sock_gettype(so, NULL, NULL, &proto);
                if (nmp->nm_sotype != SOCK_STREAM)
                        panic("nfscon sotype");

                // Assume that SOCK_STREAM always requires a connection
                sock_setsockopt(so, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on));
                
                if (proto == IPPROTO_TCP) {
                        sock_setsockopt(so, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
                }

                sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR + sizeof (u_long)) * 3;
                rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR + sizeof (u_long)) *
                                (nmp->nm_readahead > 0 ? nmp->nm_readahead + 1 : 2);
        }

        if (sndreserve > NFS_MAXSOCKBUF)
                sndreserve = NFS_MAXSOCKBUF;
        if (rcvreserve > NFS_MAXSOCKBUF)
                rcvreserve = NFS_MAXSOCKBUF;
        error = sock_setsockopt(so, SOL_SOCKET, SO_SNDBUF, &sndreserve, sizeof(sndreserve));
        if (error) {
                goto bad;
        }
        error = sock_setsockopt(so, SOL_SOCKET, SO_RCVBUF, &rcvreserve, sizeof(rcvreserve));
        if (error) {
                goto bad;
        }

        sock_nointerrupt(so, 1);

        /* Initialize other non-zero congestion variables */
        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;
        nmp->nm_cwnd = NFS_MAXCWND / 2;     /* Initial send window */
        nmp->nm_sent = 0;
        FSDBG(529, nmp, nmp->nm_state, nmp->nm_soflags, nmp->nm_cwnd);
        nmp->nm_timeouts = 0;
        return (0);

bad:
        nfs_disconnect(nmp);
        return (error);
}

/*
 * Reconnect routine:
 * Called when a connection is broken on a reliable protocol.
 * - clean up the old socket
 * - nfs_connect() again
 * - set R_MUSTRESEND for all outstanding requests on mount point
 * If this fails the mount point is DEAD!
 * nb: Must be called with the nfs_sndlock() set on the mount point.
 */
static int
nfs_reconnect(struct nfsreq *rep)
{
        struct nfsreq *rp;
        struct nfsmount *nmp = rep->r_nmp;
        int error;

        nfs_disconnect(nmp);
        while ((error = nfs_connect(nmp, rep))) {
                if (error == EINTR || error == ERESTART)
                        return (EINTR);
                if (error == EIO)
                        return (EIO);
                nfs_down(rep->r_nmp, rep->r_procp, error, NFSSTA_TIMEO,
                        "can not connect");
                rep->r_flags |= R_TPRINTFMSG;
                if (!(nmp->nm_state & NFSSTA_MOUNTED)) {
                        /* we're not yet completely mounted and */
                        /* we can't reconnect, so we fail */
                        return (error);
                }
                if ((error = nfs_sigintr(rep->r_nmp, rep, rep->r_procp)))
                        return (error);
                tsleep((caddr_t)&lbolt, PSOCK, "nfscon", 0);
        }

        /*
         * Loop through outstanding request list and fix up all requests
         * on old socket.
         */
        TAILQ_FOREACH(rp, &nfs_reqq, r_chain) {
                if (rp->r_nmp == nmp)
                        rp->r_flags |= R_MUSTRESEND;
        }
        return (0);
}

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

        if (nmp->nm_so) {
                so = nmp->nm_so;
                nmp->nm_so = 0;
                sock_shutdown(so, 2);
                sock_close(so);
        }
}

/*
 * This is the nfs send routine. For connection based socket types, it
 * must be called with an nfs_sndlock() on the socket.
 * "rep == NULL" indicates that it has been called from a server.
 * For the client side:
 * - return EINTR if the RPC is terminated, 0 otherwise
 * - set R_MUSTRESEND if the send fails for any reason
 * - do any cleanup required by recoverable socket errors (???)
 * For the server side:
 * - 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
nfs_send(so, nam, top, rep)
        socket_t so;
        mbuf_t nam;
        mbuf_t top;
        struct nfsreq *rep;
{
        struct sockaddr *sendnam;
        int error, error2, sotype, flags;
        u_long xidqueued = 0;
        struct nfsreq *rp;
        char savenametolog[MAXPATHLEN];
        struct msghdr msg;
        
        if (rep) {
                error = nfs_sigintr(rep->r_nmp, rep, rep->r_procp);
                if (error) {
                        mbuf_freem(top);
                        return (error);
                }
                if ((so = rep->r_nmp->nm_so) == NULL) {
                        rep->r_flags |= R_MUSTRESEND;
                        mbuf_freem(top);
                        return (0);
                }
                rep->r_flags &= ~R_MUSTRESEND;
                TAILQ_FOREACH(rp, &nfs_reqq, r_chain)
                        if (rp == rep)
                                break;
                if (rp)
                        xidqueued = rp->r_xid;
        }
        sock_gettype(so, NULL, &sotype, NULL);
        if ((sotype == SOCK_STREAM) || (sock_isconnected(so)) ||
            (nam == 0))
                sendnam = (struct sockaddr *)0;
        else
                sendnam = mbuf_data(nam);

        if (sotype == SOCK_SEQPACKET)
                flags = MSG_EOR;
        else
                flags = 0;

        /* 
         * Save the name here in case mount point goes away if we block.
         * The name is using local stack and is large, but don't
         * want to block if we malloc.
         */
        if (rep)
                strncpy(savenametolog,
                        vfs_statfs(rep->r_nmp->nm_mountp)->f_mntfromname,
                        MAXPATHLEN - 1);
        bzero(&msg, sizeof(msg));
        msg.msg_name = (caddr_t)sendnam;
        msg.msg_namelen = sendnam == 0 ? 0 : sendnam->sa_len;
        error = sock_sendmbuf(so, &msg, top, flags, NULL);

        if (error) {
                if (rep) {
                        if (xidqueued) {
                                TAILQ_FOREACH(rp, &nfs_reqq, r_chain)
                                        if (rp == rep && rp->r_xid == xidqueued)
                                                break;
                                if (!rp)
                                        panic("nfs_send: error %d xid %x gone",
                                              error, xidqueued);
                        }
                        log(LOG_INFO, "nfs send error %d for server %s\n",
                            error, savenametolog);
                        /*
                         * Deal with errors for the client side.
                         */
                        error2 = nfs_sigintr(rep->r_nmp, rep, rep->r_procp);
                        if (error2) {
                                error = error2;
                        } else {
                                rep->r_flags |= R_MUSTRESEND;
                        }
                } else
                        log(LOG_INFO, "nfsd send error %d\n", error);

                /*
                 * Handle any recoverable (soft) socket errors here. (???)
                 */
                if (error != EINTR && error != ERESTART && error != EIO &&
                        error != EWOULDBLOCK && error != EPIPE) {
                        error = 0;
                }
        }
        return (error);
}

/*
 * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
 * done by soreceive(), but for SOCK_STREAM we must deal with the Record
 * Mark and consolidate the data into a new mbuf list.
 * nb: Sometimes TCP passes the data up to soreceive() in long lists of
 *     small mbufs.
 * For SOCK_STREAM we must be very careful to read an entire record once
 * we have read any of it, even if the system call has been interrupted.
 */
static int
nfs_receive(struct nfsreq *rep, mbuf_t *mp)
{
        socket_t so;
        struct iovec_32 aio;
        mbuf_t m, mlast;
        u_long len, fraglen;
        int error, error2, sotype;
        proc_t p = current_proc();      /* XXX */
        struct msghdr msg;
        size_t rcvlen;
        int lastfragment;

        /*
         * Set up arguments for soreceive()
         */
        *mp = NULL;
        sotype = rep->r_nmp->nm_sotype;

        /*
         * For reliable protocols, lock against other senders/receivers
         * in case a reconnect is necessary.
         * For SOCK_STREAM, first get the Record Mark to find out how much
         * more there is to get.
         * We must lock the socket against other receivers
         * until we have an entire rpc request/reply.
         */
        if (sotype != SOCK_DGRAM) {
                error = nfs_sndlock(rep);
                if (error)
                        return (error);
tryagain:
                /*
                 * Check for fatal errors and resending request.
                 */
                /*
                 * Ugh: If a reconnect attempt just happened, nm_so
                 * would have changed. NULL indicates a failed
                 * attempt that has essentially shut down this
                 * mount point.
                 */
                if ((error = nfs_sigintr(rep->r_nmp, rep, p)) || rep->r_mrep) {
                        nfs_sndunlock(rep);
                        if (error)
                                return (error);
                        return (EINTR);
                }
                so = rep->r_nmp->nm_so;
                if (!so) {
                        error = nfs_reconnect(rep);
                        if (error) {
                                nfs_sndunlock(rep);
                                return (error);
                        }
                        goto tryagain;
                }
                while (rep->r_flags & R_MUSTRESEND) {
                        error = mbuf_copym(rep->r_mreq, 0, MBUF_COPYALL, MBUF_WAITOK, &m);
                        if (!error) {
                                OSAddAtomic(1, (SInt32*)&nfsstats.rpcretries);
                                error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
                        }
                        /*
                         * we also hold rcv lock so rep is still
                         * legit this point
                         */
                        if (error) {
                                if (error == EINTR || error == ERESTART ||
                                    (error = nfs_reconnect(rep))) {
                                        nfs_sndunlock(rep);
                                        return (error);
                                }
                                goto tryagain;
                        }
                }
                nfs_sndunlock(rep);
                if (sotype == SOCK_STREAM) {
                        error = 0;
                        len = 0;
                        lastfragment = 0;
                        mlast = NULL;
                        while (!error && !lastfragment) {
                                aio.iov_base = (uintptr_t) &fraglen;
                                aio.iov_len = sizeof(u_long);
                                bzero(&msg, sizeof(msg));
                                msg.msg_iov = (struct iovec *) &aio;
                                msg.msg_iovlen = 1;
                                do {
                                   error = sock_receive(so, &msg, MSG_WAITALL, &rcvlen);
                                   if (!rep->r_nmp) /* if unmounted then bailout */
                                        goto shutout;
                                   if (error == EWOULDBLOCK && rep) {
                                        error2 = nfs_sigintr(rep->r_nmp, rep, p);
                                        if (error2)
                                                error = error2;
                                   }
                                } while (error == EWOULDBLOCK);
                                if (!error && rcvlen < aio.iov_len) {
                                    /* only log a message if we got a partial word */
                                    if (rcvlen != 0)
                                            log(LOG_INFO,
                                                 "short receive (%d/%d) from nfs server %s\n",
                                                 rcvlen, sizeof(u_long),
                                                 vfs_statfs(rep->r_nmp->nm_mountp)->f_mntfromname);
                                    error = EPIPE;
                                }
                                if (error)
                                        goto errout;
                                lastfragment = ntohl(fraglen) & 0x80000000;
                                fraglen = ntohl(fraglen) & ~0x80000000;
                                len += fraglen;
                                /*
                                 * This is SERIOUS! We are out of sync with the sender
                                 * and forcing a disconnect/reconnect is all I can do.
                                 */
                                if (len > NFS_MAXPACKET) {
                                    log(LOG_ERR, "%s (%d) from nfs server %s\n",
                                        "impossible RPC record length", len,
                                        vfs_statfs(rep->r_nmp->nm_mountp)->f_mntfromname);
                                    error = EFBIG;
                                    goto errout;
                                }

                                m = NULL;
                                do {
                                    rcvlen = fraglen;
                                    error = sock_receivembuf(so, NULL, &m, MSG_WAITALL, &rcvlen);
                                    if (!rep->r_nmp) /* if unmounted then bailout */ {
                                        goto shutout;
                                    }
                                } while (error == EWOULDBLOCK || error == EINTR ||
                                         error == ERESTART);

                                if (!error && fraglen > rcvlen) {
                                    log(LOG_INFO,
                                        "short receive (%d/%d) from nfs server %s\n",
                                        rcvlen, fraglen,
                                        vfs_statfs(rep->r_nmp->nm_mountp)->f_mntfromname);
                                    error = EPIPE;
                                    mbuf_freem(m);
                                }
                                if (!error) {
                                        if (!*mp) {
                                                *mp = m;
                                                mlast = m;
                                        } else {
                                                error = mbuf_setnext(mlast, m);
                                                if (error) {
                                                        printf("nfs_receive: mbuf_setnext failed %d\n", error);
                                                        mbuf_freem(m);
                                                }
                                        }
                                        while (mbuf_next(mlast))
                                                mlast = mbuf_next(mlast);
                                }
                        }
                } else {
                        bzero(&msg, sizeof(msg));
                        do {
                            rcvlen = 100000000;
                            error = sock_receivembuf(so, &msg, mp, 0, &rcvlen);
                            if (!rep->r_nmp) /* if unmounted then bailout */ {
                                goto shutout;
                            }   
                            if (error == EWOULDBLOCK && rep) {
                                error2 = nfs_sigintr(rep->r_nmp, rep, p);
                                if (error2) {
                                        return (error2);
                                }
                            }
                        } while (error == EWOULDBLOCK);

                        if ((msg.msg_flags & MSG_EOR) == 0)
                                printf("Egad!!\n");
                        if (!error && *mp == NULL)
                                error = EPIPE;
                        len = rcvlen;
                }
errout:
                if (error && error != EINTR && error != ERESTART) {
                        mbuf_freem(*mp);
                        *mp = NULL;
                        if (error != EPIPE)
                                log(LOG_INFO,
                                    "receive error %d from nfs server %s\n", error,
                                    vfs_statfs(rep->r_nmp->nm_mountp)->f_mntfromname);
                        error = nfs_sndlock(rep);
                        if (!error) {
                                error = nfs_reconnect(rep);
                                if (!error)
                                        goto tryagain;
                                nfs_sndunlock(rep);
                        }
                }
        } else {
                /*
                 * We could have failed while rebinding the datagram socket
                 * so we need to attempt to rebind here.
                 */
                if ((so = rep->r_nmp->nm_so) == NULL) {
                        error = nfs_sndlock(rep);
                        if (!error) {
                                error = nfs_reconnect(rep);
                                nfs_sndunlock(rep);
                        }
                        if (error)
                                return (error);
                        if (!rep->r_nmp) /* if unmounted then bailout */
                                return (ENXIO);
                        so = rep->r_nmp->nm_so;
                }
                bzero(&msg, sizeof(msg));
                len = 0;
                do {
                        rcvlen = 1000000;
                        error = sock_receivembuf(so, &msg, mp, 0, &rcvlen);
                        if (!rep->r_nmp) /* if unmounted then bailout */
                                goto shutout;
                        if (error) {
                                error2 = nfs_sigintr(rep->r_nmp, rep, p);
                                if (error2) {
                                        error = error2;
                                        goto shutout;
                                }
                        }
                        /* Reconnect for all errors.  We may be receiving
                         * soft/hard/blocking errors because of a network
                         * change.
                         * XXX: we should rate limit or delay this
                         * to once every N attempts or something.
                         * although TCP doesn't seem to.
                         */
                        if (error) {
                                error2 = nfs_sndlock(rep);
                                if (!error2) {
                                        error2 = nfs_reconnect(rep);
                                        if (error2)
                                                error = error2;
                                        else if (!rep->r_nmp) /* if unmounted then bailout */
                                                error = ENXIO;
                                        else
                                                so = rep->r_nmp->nm_so;
                                        nfs_sndunlock(rep);
                                } else {
                                        error = error2;
                                }
                        }
                } while (error == EWOULDBLOCK);
        }
shutout:
        if (error) {
                mbuf_freem(*mp);
                *mp = NULL;
        }
        return (error);
}

/*
 * Implement receipt of reply on a socket.
 * We must search through the list of received datagrams matching them
 * with outstanding requests using the xid, until ours is found.
 */
/* ARGSUSED */
int
nfs_reply(myrep)
        struct nfsreq *myrep;
{
        struct nfsreq *rep;
        struct nfsmount *nmp = myrep->r_nmp;
        long t1;
        mbuf_t mrep, md;
        u_long rxid, *tl;
        caddr_t dpos, cp2;
        int error;

        /*
         * Loop around until we get our own reply
         */
        for (;;) {
                /*
                 * Lock against other receivers so that I don't get stuck in
                 * sbwait() after someone else has received my reply for me.
                 * Also necessary for connection based protocols to avoid
                 * race conditions during a reconnect.
                 * If nfs_rcvlock() returns EALREADY, that means that
                 * the reply has already been recieved by another
                 * process and we can return immediately.  In this
                 * case, the lock is not taken to avoid races with
                 * other processes.
                 */
                error = nfs_rcvlock(myrep);
                if (error == EALREADY)
                        return (0);
                if (error)
                        return (error);
                
                /*
                 * If we slept after putting bits otw, then reply may have
                 * arrived.  In which case returning is required, or we
                 * would hang trying to nfs_receive an already received reply.
                 */
                if (myrep->r_mrep != NULL) {
                        nfs_rcvunlock(myrep);
                        FSDBG(530, myrep->r_xid, myrep, myrep->r_nmp, -1);
                        return (0);
                }
                /*
                 * Get the next Rpc reply off the socket. Assume myrep->r_nmp
                 * is still intact by checks done in nfs_rcvlock.
                 */
                error = nfs_receive(myrep, &mrep);
                /*
                 * Bailout asap if nfsmount struct gone (unmounted). 
                 */
                if (!myrep->r_nmp) {
                        FSDBG(530, myrep->r_xid, myrep, nmp, -2);
                        if (mrep)
                                mbuf_freem(mrep);
                        return (ENXIO);
                }
                if (error) {
                        FSDBG(530, myrep->r_xid, myrep, nmp, error);
                        nfs_rcvunlock(myrep);

                        /* Bailout asap if nfsmount struct gone (unmounted). */
                        if (!myrep->r_nmp) {
                                if (mrep)
                                        mbuf_freem(mrep);
                                return (ENXIO);
                        }

                        /*
                         * Ignore routing errors on connectionless protocols??
                         */
                        if (NFSIGNORE_SOERROR(nmp->nm_sotype, error)) {
                                if (nmp->nm_so) {
                                        int clearerror;
                                        int optlen = sizeof(clearerror);
                                        sock_getsockopt(nmp->nm_so, SOL_SOCKET, SO_ERROR, &clearerror, &optlen);
                                }
                                continue;
                        }
                        if (mrep)
                                mbuf_freem(mrep);
                        return (error);
                }

                /*
                 * We assume all is fine, but if we did not have an error
                 * and mrep is 0, better not dereference it. nfs_receive
                 * calls soreceive which carefully sets error=0 when it got
                 * errors on sbwait (tsleep). In most cases, I assume that's 
                 * so we could go back again. In tcp case, EPIPE is returned.
                 * In udp, case nfs_receive gets back here with no error and no
                 * mrep. Is the right fix to have soreceive check for process
                 * aborted after sbwait and return something non-zero? Should
                 * nfs_receive give an EPIPE?  Too risky to play with those
                 * two this late in game for a shutdown problem. Instead,
                 * just check here and get out. (ekn)
                 */
                if (!mrep) {
                        nfs_rcvunlock(myrep);
                        FSDBG(530, myrep->r_xid, myrep, nmp, -3);
                        return (ENXIO); /* sounds good */
                }
                        
                /*
                 * Get the xid and check that it is an rpc reply
                 */
                md = mrep;
                dpos = mbuf_data(md);
                nfsm_dissect(tl, u_long *, 2*NFSX_UNSIGNED);
                rxid = *tl++;
                if (*tl != rpc_reply) {
                        OSAddAtomic(1, (SInt32*)&nfsstats.rpcinvalid);
                        mbuf_freem(mrep);
nfsmout:
                        if (nmp->nm_state & NFSSTA_RCVLOCK)
                                nfs_rcvunlock(myrep);
                        continue;
                }

                /*
                 * Loop through the request list to match up the reply
                 * Iff no match, just drop the datagram
                 */
                TAILQ_FOREACH(rep, &nfs_reqq, r_chain) {
                        if (rep->r_mrep == NULL && rxid == rep->r_xid) {
                                /* Found it.. */
                                rep->r_mrep = mrep;
                                rep->r_md = md;
                                rep->r_dpos = dpos;
                                /*
                                 * If we're tracking the round trip time
                                 * then we update the circular log here
                                 * with the stats from our current request.
                                 */
                                if (nfsrtton) {
                                        struct rttl *rt;

                                        rt = &nfsrtt.rttl[nfsrtt.pos];
                                        rt->proc = rep->r_procnum;
                                        rt->rto = NFS_RTO(nmp, proct[rep->r_procnum]);
                                        rt->sent = nmp->nm_sent;
                                        rt->cwnd = nmp->nm_cwnd;
                                        if (proct[rep->r_procnum] == 0)
                                                panic("nfs_reply: proct[%d] is zero", rep->r_procnum);
                                        rt->srtt = nmp->nm_srtt[proct[rep->r_procnum] - 1];
                                        rt->sdrtt = nmp->nm_sdrtt[proct[rep->r_procnum] - 1];
                                        rt->fsid = vfs_statfs(nmp->nm_mountp)->f_fsid;
                                        microtime(&rt->tstamp); // XXX unused
                                        if (rep->r_flags & R_TIMING)
                                                rt->rtt = rep->r_rtt;
                                        else
                                                rt->rtt = 1000000;
                                        nfsrtt.pos = (nfsrtt.pos + 1) % NFSRTTLOGSIZ;
                                }
                                /*
                                 * Update congestion window.
                                 * Do the additive increase of
                                 * one rpc/rtt.
                                 */
                                FSDBG(530, rep->r_xid, rep, 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 (rep->r_flags & R_SENT) {
                                    rep->r_flags &= ~R_SENT;
                                    nmp->nm_sent -= NFS_CWNDSCALE;
                               }
                                /*
                                 * Update rtt using a gain of 0.125 on the mean
                                 * and a gain of 0.25 on the deviation.
                                 */
                                if (rep->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[rep->r_procnum] == 0)
                                                panic("nfs_reply: proct[%d] is zero", rep->r_procnum);
                                        t1 = rep->r_rtt + 1;
                                        t1 -= (NFS_SRTT(rep) >> 3);
                                        NFS_SRTT(rep) += t1;
                                        if (t1 < 0)
                                                t1 = -t1;
                                        t1 -= (NFS_SDRTT(rep) >> 2);
                                        NFS_SDRTT(rep) += t1;
                                }
                                nmp->nm_timeouts = 0;
                                break;
                        }
                }
                nfs_rcvunlock(myrep);
                /*
                 * If not matched to a request, drop it.
                 * If it's mine, get out.
                 */
                if (rep == 0) {
                        OSAddAtomic(1, (SInt32*)&nfsstats.rpcunexpected);
                        mbuf_freem(mrep);
                } else if (rep == myrep) {
                        if (rep->r_mrep == NULL)
                                panic("nfs_reply: nil r_mrep");
                        return (0);
                }
                FSDBG(530, myrep->r_xid, myrep, rep,
                      rep ? rep->r_xid : myrep->r_flags);
        }
}

/*
 * nfs_request - goes something like this
 *      - fill in request struct
 *      - links it into list
 *      - calls nfs_send() for first transmit
 *      - calls nfs_receive() to get reply
 *      - break down rpc header and return with nfs reply pointed to
 *        by mrep or error
 * nb: always frees up mreq mbuf list
 */
int
nfs_request(vp, mp, mrest, procnum, procp, cred, mrp, mdp, dposp, xidp)
        vnode_t vp;
        mount_t mp;
        mbuf_t mrest;
        int procnum;
        proc_t procp;
        kauth_cred_t cred;
        mbuf_t *mrp;
        mbuf_t *mdp;
        caddr_t *dposp;
        u_int64_t *xidp;
{
        mbuf_t m, mrep, m2;
        struct nfsreq re, *rep;
        u_long *tl;
        int i;
        struct nfsmount *nmp;
        mbuf_t md, mheadend;
        char nickv[RPCX_NICKVERF];
        time_t waituntil;
        caddr_t dpos, cp2;
        int t1, error = 0, mrest_len, auth_len, auth_type;
        int trylater_delay = NFS_TRYLATERDEL, failed_auth = 0;
        int verf_len, verf_type;
        u_long xid;
        char *auth_str, *verf_str;
        NFSKERBKEY_T key;               /* save session key */
        int nmsotype;
        struct timeval now;

        if (mrp)
                *mrp = NULL;
        if (xidp)
                *xidp = 0;
        nmp = VFSTONFS(mp);

        rep = &re;

        if (vp)
                nmp = VFSTONFS(vnode_mount(vp));
        if (nmp == NULL ||
            (nmp->nm_state & (NFSSTA_FORCE|NFSSTA_TIMEO)) ==
            (NFSSTA_FORCE|NFSSTA_TIMEO)) {
                mbuf_freem(mrest);
                return (ENXIO);
        }
        nmsotype = nmp->nm_sotype;

        FSDBG_TOP(531, vp, procnum, nmp, rep);

        rep->r_nmp = nmp;
        rep->r_vp = vp;
        rep->r_procp = procp;
        rep->r_procnum = procnum;
        microuptime(&now);
        rep->r_lastmsg = now.tv_sec -
            ((nmp->nm_tprintf_delay) - (nmp->nm_tprintf_initial_delay));
        i = 0;
        m = mrest;
        while (m) {
                i += mbuf_len(m);
                m = mbuf_next(m);
        }
        mrest_len = i;

        /*
         * Get the RPC header with authorization.
         */
kerbauth:
        nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;
        if (!nmp) {
                FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                mbuf_freem(mrest);
                return (ENXIO);
        }
        verf_str = auth_str = (char *)0;
        if (nmp->nm_flag & NFSMNT_KERB) {
                verf_str = nickv;
                verf_len = sizeof (nickv);
                auth_type = RPCAUTH_KERB4;
                bzero((caddr_t)key, sizeof (key));
                if (failed_auth || nfs_getnickauth(nmp, cred, &auth_str,
                        &auth_len, verf_str, verf_len)) {
                        nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;
                        if (!nmp) {
                                FSDBG_BOT(531, 2, vp, error, rep);
                                mbuf_freem(mrest);
                                return (ENXIO);
                        }
                        error = nfs_getauth(nmp, rep, cred, &auth_str,
                                &auth_len, verf_str, &verf_len, key);
                        nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;
                        if (!error && !nmp)
                                error = ENXIO;
                        if (error) {
                                FSDBG_BOT(531, 2, vp, error, rep);
                                mbuf_freem(mrest);
                                return (error);
                        }
                }
        } else {
                auth_type = RPCAUTH_UNIX;
                if (cred->cr_ngroups < 1)
                        panic("nfsreq nogrps");
                auth_len = ((((cred->cr_ngroups - 1) > nmp->nm_numgrps) ?
                        nmp->nm_numgrps : (cred->cr_ngroups - 1)) << 2) +
                        5 * NFSX_UNSIGNED;
        }
        error = nfsm_rpchead(cred, nmp->nm_flag, procnum, auth_type, auth_len,
             auth_str, verf_len, verf_str, mrest, mrest_len, &mheadend, &xid, &m);
        if (auth_str)
                _FREE(auth_str, M_TEMP);
        if (error) {
                mbuf_freem(mrest);
                FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                return (error);
        }
        if (xidp)
                *xidp = ntohl(xid) + ((u_int64_t)nfs_xidwrap << 32);

        /*
         * For stream protocols, insert a Sun RPC Record Mark.
         */
        if (nmsotype == SOCK_STREAM) {
                error = mbuf_prepend(&m, NFSX_UNSIGNED, MBUF_WAITOK);
                if (error) {
                        mbuf_freem(m);
                        FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                        return (error);
                }
                *((u_long*)mbuf_data(m)) =
                        htonl(0x80000000 | (mbuf_pkthdr_len(m) - NFSX_UNSIGNED));
        }
        rep->r_mreq = m;
        rep->r_xid = xid;
tryagain:
        nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;
        if (nmp && (nmp->nm_flag & NFSMNT_SOFT))
                rep->r_retry = nmp->nm_retry;
        else
                rep->r_retry = NFS_MAXREXMIT + 1;       /* past clip limit */
        rep->r_rtt = rep->r_rexmit = 0;
        if (proct[procnum] > 0)
                rep->r_flags = R_TIMING;
        else
                rep->r_flags = 0;
        rep->r_mrep = NULL;

        /*
         * Do the client side RPC.
         */
        OSAddAtomic(1, (SInt32*)&nfsstats.rpcrequests);
        /*
         * Chain request into list of outstanding requests. Be sure
         * to put it LAST so timer finds oldest requests first.
         */
        TAILQ_INSERT_TAIL(&nfs_reqq, rep, r_chain);

        /*
         * If backing off another request or avoiding congestion, don't
         * send this one now but let timer do it. If not timing a request,
         * do it now.
         */
        if (nmp && nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
                           (nmp->nm_flag & NFSMNT_DUMBTIMR) ||
                           nmp->nm_sent < nmp->nm_cwnd)) {
                int connrequired = (nmp->nm_sotype == SOCK_STREAM);

                if (connrequired)
                        error = nfs_sndlock(rep);

                /*
                 * Set the R_SENT before doing the send in case another thread
                 * processes the reply before the nfs_send returns here
                 */
                if (!error) {
                        if ((rep->r_flags & R_MUSTRESEND) == 0) {
                                FSDBG(531, rep->r_xid, rep, nmp->nm_sent,
                                      nmp->nm_cwnd);
                                nmp->nm_sent += NFS_CWNDSCALE;
                                rep->r_flags |= R_SENT;
                        }

                        error = mbuf_copym(m, 0, MBUF_COPYALL, MBUF_WAITOK, &m2);
                        if (!error)
                                error = nfs_send(nmp->nm_so, nmp->nm_nam, m2, rep);
                        if (connrequired)
                                nfs_sndunlock(rep);
                }
                nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;
                if (error) {
                        if (nmp)
                                nmp->nm_sent -= NFS_CWNDSCALE;
                        rep->r_flags &= ~R_SENT;
                }
        } else {
                rep->r_rtt = -1;
        }

        /*
         * Wait for the reply from our send or the timer's.
         */
        if (!error || error == EPIPE)
                error = nfs_reply(rep);

        /*
         * RPC done, unlink the request.
         */
        nfs_repdequeue(rep);

        nmp = vp ? VFSTONFS(vnode_mount(vp)) : rep->r_nmp;

        /*
         * Decrement the outstanding request count.
         */
        if (rep->r_flags & R_SENT) {
                rep->r_flags &= ~R_SENT;        /* paranoia */
                if (nmp) {
                        FSDBG(531, rep->r_xid, rep, nmp->nm_sent, nmp->nm_cwnd);
                        nmp->nm_sent -= NFS_CWNDSCALE;
                }
        }

        /*
         * If there was a successful reply and a tprintf msg.
         * tprintf a response.
         */
        if (!error)
                nfs_up(nmp, procp, NFSSTA_TIMEO,
                        (rep->r_flags & R_TPRINTFMSG) ? "is alive again" : NULL);
        mrep = rep->r_mrep;
        md = rep->r_md;
        dpos = rep->r_dpos;
        if (!error && !nmp)
                error = ENXIO;
        if (error) {
                mbuf_freem(rep->r_mreq);
                FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                return (error);
        }

        /*
         * break down the rpc header and check if ok
         */
        nfsm_dissect(tl, u_long *, 3 * NFSX_UNSIGNED);
        if (*tl++ == rpc_msgdenied) {
                if (*tl == rpc_mismatch)
                        error = EOPNOTSUPP;
                else if ((nmp->nm_flag & NFSMNT_KERB) && *tl++ == rpc_autherr) {
                        if (!failed_auth) {
                                failed_auth++;
                                error = mbuf_setnext(mheadend, NULL);
                                mbuf_freem(mrep);
                                mbuf_freem(rep->r_mreq);
                                if (!error)
                                        goto kerbauth;
                                printf("nfs_request: mbuf_setnext failed\n");
                        } else
                                error = EAUTH;
                } else
                        error = EACCES;
                mbuf_freem(mrep);
                mbuf_freem(rep->r_mreq);
                FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                return (error);
        }

        /*
         * Grab any Kerberos verifier, otherwise just throw it away.
         */
        verf_type = fxdr_unsigned(int, *tl++);
        i = fxdr_unsigned(int, *tl);
        if ((nmp->nm_flag & NFSMNT_KERB) && verf_type == RPCAUTH_KERB4) {
                error = nfs_savenickauth(nmp, cred, i, key, &md, &dpos, mrep);
                if (error)
                        goto nfsmout;
        } else if (i > 0)
                nfsm_adv(nfsm_rndup(i));
        nfsm_dissect(tl, u_long *, NFSX_UNSIGNED);
        /* 0 == ok */
        if (*tl == 0) {
                nfsm_dissect(tl, u_long *, NFSX_UNSIGNED);
                if (*tl != 0) {
                        error = fxdr_unsigned(int, *tl);
                        if ((nmp->nm_flag & NFSMNT_NFSV3) &&
                                error == NFSERR_TRYLATER) {
                                mbuf_freem(mrep);
                                error = 0;
                                microuptime(&now);
                                waituntil = now.tv_sec + trylater_delay;
                                while (now.tv_sec < waituntil) {
                                        tsleep((caddr_t)&lbolt, PSOCK, "nfstrylater", 0);
                                        microuptime(&now);
                                }
                                trylater_delay *= 2;
                                if (trylater_delay > 60)
                                        trylater_delay = 60;
                                goto tryagain;
                        }

                        /*
                         * If the File Handle was stale, invalidate the
                         * lookup cache, just in case.
                         */
                        if ((error == ESTALE) && vp)
                                cache_purge(vp);
                        if (nmp->nm_flag & NFSMNT_NFSV3) {
                                *mrp = mrep;
                                *mdp = md;
                                *dposp = dpos;
                                error |= NFSERR_RETERR;
                        } else {
                                mbuf_freem(mrep);
                                error &= ~NFSERR_RETERR;
                        }
                        mbuf_freem(rep->r_mreq);
                        FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
                        return (error);
                }

                *mrp = mrep;
                *mdp = md;
                *dposp = dpos;
                mbuf_freem(rep->r_mreq);
                FSDBG_BOT(531, 0xf0f0f0f0, rep->r_xid, nmp, rep);
                return (0);
        }
        mbuf_freem(mrep);
        error = EPROTONOSUPPORT;
nfsmout:
        mbuf_freem(rep->r_mreq);
        FSDBG_BOT(531, error, rep->r_xid, nmp, rep);
        return (error);
}

#ifndef NFS_NOSERVER
/*
 * Generate the rpc reply header
 * siz arg. is used to decide if adding a cluster is worthwhile
 */
int
nfs_rephead(siz, nd, slp, err, mrq, mbp, bposp)
        int siz;
        struct nfsrv_descript *nd;
        struct nfssvc_sock *slp;
        int err;
        mbuf_t *mrq;
        mbuf_t *mbp;
        caddr_t *bposp;
{
        u_long *tl;
        mbuf_t mreq;
        caddr_t bpos;
        mbuf_t mb, mb2;
        int error, mlen;

        /*
         * 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, &mreq);
        } else {
                error = mbuf_gethdr(MBUF_WAITOK, MBUF_TYPE_DATA, &mreq);
        }
        if (error) {
                /* unable to allocate packet */
                /* XXX nfsstat? */
                return (error);
        }
        mb = mreq;
        tl = mbuf_data(mreq);
        mlen = 6 * NFSX_UNSIGNED;
        if (siz < nfs_mbuf_minclsize) {
                /* leave space for lower level headers */
                tl += 80/sizeof(*tl);  /* XXX max_hdr? XXX */
                mbuf_setdata(mreq, tl, mlen);
        } else {
                mbuf_setlen(mreq, mlen);
        }
        bpos = ((caddr_t)tl) + mlen;
        *tl++ = txdr_unsigned(nd->nd_retxid);
        *tl++ = rpc_reply;
        if (err == ERPCMISMATCH || (err & NFSERR_AUTHERR)) {
                *tl++ = rpc_msgdenied;
                if (err & NFSERR_AUTHERR) {
                        *tl++ = rpc_autherr;
                        *tl = txdr_unsigned(err & ~NFSERR_AUTHERR);
                        mlen -= NFSX_UNSIGNED;
                        mbuf_setlen(mreq, mlen);
                        bpos -= NFSX_UNSIGNED;
                } else {
                        *tl++ = rpc_mismatch;
                        *tl++ = txdr_unsigned(RPC_VER2);
                        *tl = txdr_unsigned(RPC_VER2);
                }
        } else {
                *tl++ = rpc_msgaccepted;

                /*
                 * For Kerberos authentication, we must send the nickname
                 * verifier back, otherwise just RPCAUTH_NULL.
                 */
                if (nd->nd_flag & ND_KERBFULL) {
                    struct nfsuid *nuidp;
                    struct timeval ktvin, ktvout;
                    uid_t uid = kauth_cred_getuid(nd->nd_cr);

                    lck_rw_lock_shared(&slp->ns_rwlock);
                    for (nuidp = NUIDHASH(slp, uid)->lh_first;
                        nuidp != 0; nuidp = nuidp->nu_hash.le_next) {
                        if (kauth_cred_getuid(nuidp->nu_cr) == uid &&
                            (!nd->nd_nam2 || netaddr_match(NU_NETFAM(nuidp),
                             &nuidp->nu_haddr, nd->nd_nam2)))
                            break;
                    }
                    if (nuidp) {
                        ktvin.tv_sec =
                            txdr_unsigned(nuidp->nu_timestamp.tv_sec - 1);
                        ktvin.tv_usec =
                            txdr_unsigned(nuidp->nu_timestamp.tv_usec);

                        /*
                         * Encrypt the timestamp in ecb mode using the
                         * session key.
                         */
#if NFSKERB
                        XXX
#endif

                        *tl++ = rpc_auth_kerb;
                        *tl++ = txdr_unsigned(3 * NFSX_UNSIGNED);
                        *tl = ktvout.tv_sec;
                        nfsm_build(tl, u_long *, 3 * NFSX_UNSIGNED);
                        *tl++ = ktvout.tv_usec;
                        *tl++ = txdr_unsigned(kauth_cred_getuid(nuidp->nu_cr));
                    } else {
                        *tl++ = 0;
                        *tl++ = 0;
                    }
                    lck_rw_done(&slp->ns_rwlock);
                } else {
                        *tl++ = 0;
                        *tl++ = 0;
                }
                switch (err) {
                case EPROGUNAVAIL:
                        *tl = txdr_unsigned(RPC_PROGUNAVAIL);
                        break;
                case EPROGMISMATCH:
                        *tl = txdr_unsigned(RPC_PROGMISMATCH);
                        nfsm_build(tl, u_long *, 2 * NFSX_UNSIGNED);
                        // XXX hard coded versions
                        *tl++ = txdr_unsigned(2);
                        *tl = txdr_unsigned(3);
                        break;
                case EPROCUNAVAIL:
                        *tl = txdr_unsigned(RPC_PROCUNAVAIL);
                        break;
                case EBADRPC:
                        *tl = txdr_unsigned(RPC_GARBAGE);
                        break;
                default:
                        *tl = 0;
                        if (err != NFSERR_RETVOID) {
                                nfsm_build(tl, u_long *, NFSX_UNSIGNED);
                                if (err)
                                    *tl = txdr_unsigned(nfsrv_errmap(nd, err));
                                else
                                    *tl = 0;
                        }
                        break;
                }
        }

        if (mrq != NULL)
                *mrq = mreq;
        *mbp = mb;
        *bposp = bpos;
        if (err != 0 && err != NFSERR_RETVOID) {
                OSAddAtomic(1, (SInt32*)&nfsstats.srvrpc_errs);
        }
        return (0);
}


#endif /* NFS_NOSERVER */


/*
 * From FreeBSD 1.58, a Matt Dillon fix...
 * Flag a request as being about to terminate.
 * The nm_sent count is decremented now to avoid deadlocks when the process
 * in soreceive() hasn't yet managed to send its own request.
 */
static void
nfs_softterm(struct nfsreq *rep)
{

        rep->r_flags |= R_SOFTTERM;
        if (rep->r_flags & R_SENT) {
                FSDBG(532, rep->r_xid, rep, rep->r_nmp->nm_sent,
                      rep->r_nmp->nm_cwnd);
                rep->r_nmp->nm_sent -= NFS_CWNDSCALE;
                rep->r_flags &= ~R_SENT;
        }
}

void
nfs_timer_funnel(void * arg)
{
        (void) thread_funnel_set(kernel_flock, TRUE);
        nfs_timer(arg);
        (void) thread_funnel_set(kernel_flock, FALSE);

}

/*
 * Ensure rep isn't in use by the timer, then dequeue it.
 */
static void
nfs_repdequeue(struct nfsreq *rep)
{

        while ((rep->r_flags & R_BUSY)) {
                rep->r_flags |= R_WAITING;
                tsleep(rep, PSOCK, "repdeq", 0);
        }
        TAILQ_REMOVE(&nfs_reqq, rep, r_chain);
}

/*
 * Busy (lock) a nfsreq, used by the nfs timer to make sure it's not
 * free()'d out from under it.
 */
static void
nfs_repbusy(struct nfsreq *rep)
{

        if ((rep->r_flags & R_BUSY))
                panic("rep locked");
        rep->r_flags |= R_BUSY;
}

/*
 * Unbusy the nfsreq passed in, return the next nfsreq in the chain busied.
 */
static struct nfsreq *
nfs_repnext(struct nfsreq *rep)
{
        struct nfsreq * nextrep;

        if (rep == 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.
         */
        nextrep = TAILQ_NEXT(rep, r_chain);
        if (nextrep != NULL)
                nfs_repbusy(nextrep);
        /* unbusy and signal. */
        rep->r_flags &= ~R_BUSY;
        if ((rep->r_flags & R_WAITING)) {
                rep->r_flags &= ~R_WAITING;
                wakeup(rep);
        }
        return (nextrep);
}

/*
 * Nfs timer routine
 * Scan the nfsreq list and retranmit any requests that have timed out
 * To avoid retransmission attempts on STREAM sockets (in the future) make
 * sure to set the r_retry field to 0 (implies nm_retry == 0).
 */
void
nfs_timer(__unused void *arg)
{
        struct nfsreq *rep;
        mbuf_t m;
        socket_t so;
        struct nfsmount *nmp;
        int timeo;
        int error;
#ifndef NFS_NOSERVER
        struct nfssvc_sock *slp;
        u_quad_t cur_usec;
#endif /* NFS_NOSERVER */
        int flags, rexmit, cwnd, sent;
        u_long xid;
        struct timeval now;

        rep = TAILQ_FIRST(&nfs_reqq);
        if (rep != NULL)
                nfs_repbusy(rep);
        microuptime(&now);
        for ( ; rep != NULL ; rep = nfs_repnext(rep)) {
                nmp = rep->r_nmp;
                if (!nmp) /* unmounted */
                    continue;
                if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
                        continue;
                if (nfs_sigintr(nmp, rep, rep->r_procp))
                        continue;
                if (nmp->nm_tprintf_initial_delay != 0 &&
                    (rep->r_rexmit > 2 || (rep->r_flags & R_RESENDERR)) &&
                    rep->r_lastmsg + nmp->nm_tprintf_delay < now.tv_sec) {
                        rep->r_lastmsg = now.tv_sec;
                        nfs_down(rep->r_nmp, rep->r_procp, 0, NFSSTA_TIMEO,
                                "not responding");
                        rep->r_flags |= R_TPRINTFMSG;
                        if (!(nmp->nm_state & NFSSTA_MOUNTED)) {
                                /* we're not yet completely mounted and */
                                /* we can't complete an RPC, so we fail */
                                OSAddAtomic(1, (SInt32*)&nfsstats.rpctimeouts);
                                nfs_softterm(rep);
                                continue;
                        }
                }
                if (rep->r_rtt >= 0) {
                        rep->r_rtt++;
                        if (nmp->nm_flag & NFSMNT_DUMBTIMR)
                                timeo = nmp->nm_timeo;
                        else
                                timeo = NFS_RTO(nmp, proct[rep->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];
                        if (rep->r_rtt <= timeo)
                                continue;
                        if (nmp->nm_timeouts < 8)
                                nmp->nm_timeouts++;
                }
                /*
                 * Check for too many retransmits.  This is never true for
                 * 'hard' mounts because we set r_retry to NFS_MAXREXMIT + 1
                 * and never allow r_rexmit to be more than NFS_MAXREXMIT.
                 */
                if (rep->r_rexmit >= rep->r_retry) {    /* too many */
                        OSAddAtomic(1, (SInt32*)&nfsstats.rpctimeouts);
                        nfs_softterm(rep);
                        continue;
                }
                if (nmp->nm_sotype != SOCK_DGRAM) {
                        if (++rep->r_rexmit > NFS_MAXREXMIT)
                                rep->r_rexmit = NFS_MAXREXMIT;
                        continue;
                }
                if ((so = nmp->nm_so) == NULL)
                        continue;

                /*
                 * If there is enough space and the window allows..
                 *      Resend it
                 * Set r_rtt to -1 in case we fail to send it now.
                 */
                rep->r_rtt = -1;
                if (((nmp->nm_flag & NFSMNT_DUMBTIMR) ||
                    (rep->r_flags & R_SENT) ||
                    nmp->nm_sent < nmp->nm_cwnd) &&
                   (mbuf_copym(rep->r_mreq, 0, MBUF_COPYALL, MBUF_DONTWAIT, &m) == 0)){
                        struct msghdr   msg;
                        /*
                         * Iff first send, start timing
                         * else turn timing off, backoff timer
                         * and divide congestion window by 2.
                         * We update these *before* the send to avoid
                         * racing against receiving the reply.
                         * We save them so we can restore them on send error.
                         */
                        flags = rep->r_flags;
                        rexmit = rep->r_rexmit;
                        cwnd = nmp->nm_cwnd;
                        sent = nmp->nm_sent;
                        xid = rep->r_xid;
                        if (rep->r_flags & R_SENT) {
                                rep->r_flags &= ~R_TIMING;
                                if (++rep->r_rexmit > NFS_MAXREXMIT)
                                        rep->r_rexmit = NFS_MAXREXMIT;
                                nmp->nm_cwnd >>= 1;
                                if (nmp->nm_cwnd < NFS_CWNDSCALE)
                                        nmp->nm_cwnd = NFS_CWNDSCALE;
                                OSAddAtomic(1, (SInt32*)&nfsstats.rpcretries);
                        } else {
                                rep->r_flags |= R_SENT;
                                nmp->nm_sent += NFS_CWNDSCALE;
                        }
                        FSDBG(535, xid, rep, nmp->nm_sent, nmp->nm_cwnd);

                        bzero(&msg, sizeof(msg));
                        if ((nmp->nm_flag & NFSMNT_NOCONN) == NFSMNT_NOCONN) {
                                msg.msg_name = mbuf_data(nmp->nm_nam);
                                msg.msg_namelen = mbuf_len(nmp->nm_nam);
                        }
                        error = sock_sendmbuf(so, &msg, m, MSG_DONTWAIT, NULL);

                        FSDBG(535, xid, error, sent, cwnd);

                        if (error) {
                                if (error == EWOULDBLOCK) {
                                        rep->r_flags = flags;
                                        rep->r_rexmit = rexmit;
                                        nmp->nm_cwnd = cwnd;
                                        nmp->nm_sent = sent;
                                        rep->r_xid = xid;
                                }
                                else {
                                        if (NFSIGNORE_SOERROR(nmp->nm_sotype, error)) {
                                                int clearerror;
                                                int optlen = sizeof(clearerror);
                                                sock_getsockopt(nmp->nm_so, SOL_SOCKET, SO_ERROR, &clearerror, &optlen);
                                        }
                                        rep->r_flags  = flags | R_RESENDERR;
                                        rep->r_rexmit = rexmit;
                                        nmp->nm_cwnd = cwnd;
                                        nmp->nm_sent = sent;
                                        if (flags & R_SENT)
                                                OSAddAtomic(-1, (SInt32*)&nfsstats.rpcretries);
                                }
                        } else
                                rep->r_rtt = 0;
                }
        }
        microuptime(&now);
#ifndef NFS_NOSERVER
        /*
         * Scan the write gathering queues for writes that need to be
         * completed now.
         */
        cur_usec = (u_quad_t)now.tv_sec * 1000000 + (u_quad_t)now.tv_usec;
        lck_mtx_lock(nfsd_mutex);
        TAILQ_FOREACH(slp, &nfssvc_sockhead, ns_chain) {
            if (slp->ns_wgtime && (slp->ns_wgtime <= cur_usec))
                nfsrv_wakenfsd(slp);
        }
        while ((slp = TAILQ_FIRST(&nfssvc_deadsockhead))) {
                if ((slp->ns_timestamp + 5) > now.tv_sec)
                        break;
                TAILQ_REMOVE(&nfssvc_deadsockhead, slp, ns_chain);
                nfsrv_slpfree(slp);
        }
        lck_mtx_unlock(nfsd_mutex);
#endif /* NFS_NOSERVER */

        if (nfsbuffreeuptimestamp + 30 <= now.tv_sec) {
                /*
                 * We haven't called nfs_buf_freeup() in a little while.
                 * So, see if we can free up any stale/unused bufs now.
                 */
                nfs_buf_freeup(1);
        }

        timeout(nfs_timer_funnel, (void *)0, nfs_ticks);

}


/*
 * Test for a termination condition pending on the process.
 * This is used to determine if we need to bail on a mount.
 * EIO 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).
 */
int
nfs_sigintr(nmp, rep, p)
        struct nfsmount *nmp;
        struct nfsreq *rep;
        proc_t p;
{
        sigset_t pending_sigs;
        int context_good = 0;
        struct nfsmount *repnmp;
        extern proc_t kernproc;

        if (nmp == NULL)
                return (ENXIO);
        if (rep != NULL) {
                repnmp = rep->r_nmp;
                /* we've had a forced unmount. */
                if (repnmp == NULL)
                        return (ENXIO);
                /* request has timed out on a 'soft' mount. */
                if (rep->r_flags & R_SOFTTERM)
                        return (EIO);
                /*
                 * We're in the progress of a force unmount and there's
                 * been a timeout we're dead and fail IO.
                 */
                if ((repnmp->nm_state & (NFSSTA_FORCE|NFSSTA_TIMEO)) ==
                   (NFSSTA_FORCE|NFSSTA_TIMEO))
                        return (EIO);
                /* Someone is unmounting us, go soft and mark it. */
                if (repnmp->nm_mountp->mnt_kern_flag & MNTK_FRCUNMOUNT) {
                        repnmp->nm_flag |= NFSMNT_SOFT;
                        nmp->nm_state |= NFSSTA_FORCE;
                }
                /*
                 * If the mount is hung and we've requested not to hang
                 * on remote filesystems, then bail now.
                 */
                if (p != NULL && (proc_noremotehang(p)) != 0 &&
                    (repnmp->nm_state & NFSSTA_TIMEO) != 0)
                        return (EIO);
        }
        /* XXX: is this valid?  this probably should be an assertion. */
        if (p == NULL)
                return (0);

        /* Is this thread belongs to kernel task; then abort check  is not needed */
        if ((current_proc() != kernproc) && current_thread_aborted()) {
                return (EINTR);
        }
        /* mask off thread and process blocked signals. */

        pending_sigs = proc_pendingsignals(p, NFSINT_SIGMASK);
        if (pending_sigs && (nmp->nm_flag & NFSMNT_INT) != 0)
                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(rep)
        struct nfsreq *rep;
{
        int *statep;
        proc_t p;
        int error, slpflag = 0, slptimeo = 0;

        if (rep->r_nmp == NULL)
                return (ENXIO);
        statep = &rep->r_nmp->nm_state;

        p = rep->r_procp;
        if (rep->r_nmp->nm_flag & NFSMNT_INT)
                slpflag = PCATCH;
        while (*statep & NFSSTA_SNDLOCK) {
                error = nfs_sigintr(rep->r_nmp, rep, p);
                if (error)
                        return (error);
                *statep |= NFSSTA_WANTSND;
                if (p != NULL && (proc_noremotehang(p)) != 0)
                        slptimeo = hz;
                tsleep((caddr_t)statep, slpflag | (PZERO - 1), "nfsndlck", slptimeo);
                if (slpflag == PCATCH) {
                        slpflag = 0;
                        slptimeo = 2 * hz;
                }
                /*
                 * Make sure while we slept that the mountpoint didn't go away.
                 * nfs_sigintr and callers expect it in tact.
                 */
                if (!rep->r_nmp) 
                        return (ENXIO); /* don't have lock until out of loop */
        }
        *statep |= NFSSTA_SNDLOCK;
        return (0);
}

/*
 * Unlock the stream socket for others.
 */
void
nfs_sndunlock(rep)
        struct nfsreq *rep;
{
        int *statep;

        if (rep->r_nmp == NULL)
                return;
        statep = &rep->r_nmp->nm_state;
        if ((*statep & NFSSTA_SNDLOCK) == 0)
                panic("nfs sndunlock");
        *statep &= ~NFSSTA_SNDLOCK;
        if (*statep & NFSSTA_WANTSND) {
                *statep &= ~NFSSTA_WANTSND;
                wakeup((caddr_t)statep);
        }
}

static int
nfs_rcvlock(struct nfsreq *rep)
{
        int *statep;
        int error, slpflag, slptimeo = 0;

        /* make sure we still have our mountpoint */
        if (!rep->r_nmp) {
                if (rep->r_mrep != NULL)
                        return (EALREADY);
                return (ENXIO);
        }

        statep = &rep->r_nmp->nm_state;
        FSDBG_TOP(534, rep->r_xid, rep, rep->r_nmp, *statep);
        if (rep->r_nmp->nm_flag & NFSMNT_INT)
                slpflag = PCATCH;
        else
                slpflag = 0;
        while (*statep & NFSSTA_RCVLOCK) {
                if ((error = nfs_sigintr(rep->r_nmp, rep, rep->r_procp))) {
                        FSDBG_BOT(534, rep->r_xid, rep, rep->r_nmp, 0x100);
                        return (error);
                } else if (rep->r_mrep != NULL) {
                        /*
                         * Don't bother sleeping if reply already arrived
                         */
                        FSDBG_BOT(534, rep->r_xid, rep, rep->r_nmp, 0x101);
                        return (EALREADY);
                }
                FSDBG(534, rep->r_xid, rep, rep->r_nmp, 0x102);
                *statep |= NFSSTA_WANTRCV;
                /*
                 * We need to poll if we're P_NOREMOTEHANG so that we
                 * call nfs_sigintr periodically above.
                 */
                if (rep->r_procp != NULL &&
                    (proc_noremotehang(rep->r_procp)) != 0)
                        slptimeo = hz;
                tsleep((caddr_t)statep, slpflag | (PZERO - 1), "nfsrcvlk", slptimeo);
                if (slpflag == PCATCH) {
                        slpflag = 0;
                        slptimeo = 2 * hz;
                }
                /*
                 * Make sure while we slept that the mountpoint didn't go away.
                 * nfs_sigintr and caller nfs_reply expect it intact.
                 */
                if (!rep->r_nmp)  {
                        FSDBG_BOT(534, rep->r_xid, rep, rep->r_nmp, 0x103);
                        return (ENXIO); /* don't have lock until out of loop */
                }
        }
        /*
         * nfs_reply will handle it if reply already arrived.
         * (We may have slept or been preempted).
         */
        FSDBG_BOT(534, rep->r_xid, rep, rep->r_nmp, *statep);
        *statep |= NFSSTA_RCVLOCK;
        return (0);
}

/*
 * Unlock the stream socket for others.
 */
static void
nfs_rcvunlock(struct nfsreq *rep)
{
        int *statep;
        
        if (rep->r_nmp == NULL)
                return;
        statep = &rep->r_nmp->nm_state;

        FSDBG(533, statep, *statep, 0, 0);
        if ((*statep & NFSSTA_RCVLOCK) == 0)
                panic("nfs rcvunlock");
        *statep &= ~NFSSTA_RCVLOCK;
        if (*statep & NFSSTA_WANTRCV) {
                *statep &= ~NFSSTA_WANTRCV;
                wakeup((caddr_t)statep);
        }
}


#ifndef NFS_NOSERVER
/*
 * Socket upcall routine for the nfsd sockets.
 * The caddr_t arg is a pointer to the "struct nfssvc_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, caddr_t arg, int waitflag)
{
        struct nfssvc_sock *slp = (struct nfssvc_sock *)arg;

        if (!nfs_numnfsd || !(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 nfssvc_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 nfsd so that there is feedback to the TCP layer that
                 * the nfs servers are heavily loaded.
                 */
                if (slp->ns_rec && waitflag == MBUF_DONTWAIT) {
                        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 = SLP_NEEDQ;
                        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;
                
                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_recend = m;
                                mbuf_setnextpkt(m, NULL);
                        }
#if 0
                        if (error) {
                                /*
                                 * This may be needed in the future to support
                                 * non-byte-stream connection-oriented protocols
                                 * such as SCTP.
                                 */
                                /*
                                 * This (slp->ns_sotype == SOCK_STREAM) should really
                                 * be a check for PR_CONNREQUIRED.
                                 */
                                if ((slp->ns_sotype == SOCK_STREAM)
                                        && error != EWOULDBLOCK) {
                                        ns_flag = SLP_DISCONN;
                                        goto dorecs;
                                }
                        }
#endif
                } 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_rec || (slp->ns_flag & (SLP_NEEDQ | SLP_DISCONN)));
                lck_rw_done(&slp->ns_rwlock);
                if (wake && nfs_numnfsd) {
                        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.
 */
static int
nfsrv_getstream(slp, waitflag)
        struct nfssvc_sock *slp;
        int waitflag;
{
        mbuf_t m;
        char *cp1, *cp2, *mdata;
        int len, mlen, error;
        mbuf_t om, m2, recm;
        u_long 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 < NFS_MINPACKET || 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_recend = slp->ns_frag;
                slp->ns_frag = NULL;
            }
        }
}

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

        *ndp = NULL;
        if ((slp->ns_flag & SLP_VALID) == 0 || (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_recend = NULL;
        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_md = nd->nd_mrep = m;
        nd->nd_nam2 = nam;
        nd->nd_dpos = mbuf_data(m);
        error = nfs_getreq(nd, nfsd, TRUE);
        if (error) {
                if (nam)
                        mbuf_freem(nam);
                FREE_ZONE((caddr_t)nd,  sizeof *nd, M_NFSRVDESC);
                return (error);
        }
        *ndp = nd;
        nfsd->nfsd_nd = nd;
        return (0);
}

/*
 * Parse an RPC request
 * - verify it
 * - fill in the cred struct.
 */
int
nfs_getreq(nd, nfsd, has_header)
        struct nfsrv_descript *nd;
        struct nfsd *nfsd;
        int has_header;
{
        int len, i;
        u_long *tl;
        long t1;
        uio_t uiop;
        caddr_t dpos, cp2, cp;
        u_long nfsvers, auth_type;
        uid_t nickuid;
        int error = 0, ticklen;
        mbuf_t mrep, md;
        struct nfsuid *nuidp;
        uid_t user_id;
        gid_t group_id;
        int ngroups;
        struct ucred temp_cred;
        struct timeval tvin, tvout, now;
        char uio_buf[ UIO_SIZEOF(1) ];
#if 0                           /* until encrypted keys are implemented */
        NFSKERBKEYSCHED_T keys; /* stores key schedule */
#endif

        nd->nd_cr = NULL;

        mrep = nd->nd_mrep;
        md = nd->nd_md;
        dpos = nd->nd_dpos;
        if (has_header) {
                nfsm_dissect(tl, u_long *, 10 * NFSX_UNSIGNED);
                nd->nd_retxid = fxdr_unsigned(u_long, *tl++);
                if (*tl++ != rpc_call) {
                        mbuf_freem(mrep);
                        return (EBADRPC);
                }
        } else
                nfsm_dissect(tl, u_long *, 8 * NFSX_UNSIGNED);
        nd->nd_repstat = 0;
        nd->nd_flag = 0;
        if (*tl++ != rpc_vers) {
                nd->nd_repstat = ERPCMISMATCH;
                nd->nd_procnum = NFSPROC_NOOP;
                return (0);
        }
        if (*tl != nfs_prog) {
                nd->nd_repstat = EPROGUNAVAIL;
                nd->nd_procnum = NFSPROC_NOOP;
                return (0);
        }
        tl++;
        nfsvers = fxdr_unsigned(u_long, *tl++);
        if ((nfsvers < NFS_VER2) || (nfsvers > NFS_VER3)) {
                nd->nd_repstat = EPROGMISMATCH;
                nd->nd_procnum = NFSPROC_NOOP;
                return (0);
        }
        else if (nfsvers == NFS_VER3)
                nd->nd_flag = ND_NFSV3;
        nd->nd_procnum = fxdr_unsigned(u_long, *tl++);
        if (nd->nd_procnum == NFSPROC_NULL)
                return (0);
        if ((nd->nd_procnum >= NFS_NPROCS) ||
                (!nd->nd_flag && nd->nd_procnum > NFSV2PROC_STATFS)) {
                nd->nd_repstat = EPROCUNAVAIL;
                nd->nd_procnum = NFSPROC_NOOP;
                return (0);
        }
        if ((nd->nd_flag & ND_NFSV3) == 0)
                nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
        auth_type = *tl++;
        len = fxdr_unsigned(int, *tl++);
        if (len < 0 || len > RPCAUTH_MAXSIZ) {
                mbuf_freem(mrep);
                return (EBADRPC);
        }

        nd->nd_flag &= ~ND_KERBAUTH;
        /*
         * Handle auth_unix or auth_kerb.
         */
        if (auth_type == rpc_auth_unix) {
                len = fxdr_unsigned(int, *++tl);
                if (len < 0 || len > NFS_MAXNAMLEN) {
                        mbuf_freem(mrep);
                        return (EBADRPC);
                }
                bzero(&temp_cred, sizeof(temp_cred));
                nfsm_adv(nfsm_rndup(len));
                nfsm_dissect(tl, u_long *, 3 * NFSX_UNSIGNED);
                user_id = fxdr_unsigned(uid_t, *tl++);
                group_id = fxdr_unsigned(gid_t, *tl++);
                temp_cred.cr_groups[0] = group_id;
                len = fxdr_unsigned(int, *tl);
                if (len < 0 || len > RPCAUTH_UNIXGIDS) {
                        mbuf_freem(mrep);
                        return (EBADRPC);
                }
                nfsm_dissect(tl, u_long *, (len + 2) * NFSX_UNSIGNED);
                for (i = 1; i <= len; i++)
                    if (i < NGROUPS)
                        temp_cred.cr_groups[i] = fxdr_unsigned(gid_t, *tl++);
                    else
                        tl++;
                ngroups = (len >= NGROUPS) ? NGROUPS : (len + 1);
                if (ngroups > 1)
                    nfsrvw_sort(&temp_cred.cr_groups[0], ngroups);
                len = fxdr_unsigned(int, *++tl);
                if (len < 0 || len > RPCAUTH_MAXSIZ) {
                        mbuf_freem(mrep);
                        return (EBADRPC);
                }
                temp_cred.cr_uid = user_id;
                temp_cred.cr_ngroups = ngroups;
                nd->nd_cr = kauth_cred_create(&temp_cred); 
                if (nd->nd_cr == NULL) {
                        nd->nd_repstat = ENOMEM;
                        nd->nd_procnum = NFSPROC_NOOP;
                        return (0);
                }
                if (len > 0)
                        nfsm_adv(nfsm_rndup(len));
        } else if (auth_type == rpc_auth_kerb) {
                switch (fxdr_unsigned(int, *tl++)) {
                case RPCAKN_FULLNAME:
                        ticklen = fxdr_unsigned(int, *tl);
                        *((u_long *)nfsd->nfsd_authstr) = *tl;
                        uiop = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, 
                                                &uio_buf[0], sizeof(uio_buf));
                        if (!uiop) {
                                nd->nd_repstat = ENOMEM;
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }

                        // LP64todo - fix this
                        nfsd->nfsd_authlen = (nfsm_rndup(ticklen) + (NFSX_UNSIGNED * 2));
                        if ((nfsm_rndup(ticklen) + NFSX_UNSIGNED) > (len - 2 * NFSX_UNSIGNED)) {
                                mbuf_freem(mrep);
                                return (EBADRPC);
                        }
                        uio_addiov(uiop, CAST_USER_ADDR_T(&nfsd->nfsd_authstr[4]), RPCAUTH_MAXSIZ - 4);
                        // LP64todo - fix this
                        nfsm_mtouio(uiop, uio_resid(uiop));
                        nfsm_dissect(tl, u_long *, 2 * NFSX_UNSIGNED);
                        if (*tl++ != rpc_auth_kerb ||
                                fxdr_unsigned(int, *tl) != 4 * NFSX_UNSIGNED) {
                                printf("Bad kerb verifier\n");
                                nd->nd_repstat = (NFSERR_AUTHERR|AUTH_BADVERF);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        nfsm_dissect(cp, caddr_t, 4 * NFSX_UNSIGNED);
                        tl = (u_long *)cp;
                        if (fxdr_unsigned(int, *tl) != RPCAKN_FULLNAME) {
                                printf("Not fullname kerb verifier\n");
                                nd->nd_repstat = (NFSERR_AUTHERR|AUTH_BADVERF);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        cp += NFSX_UNSIGNED;
                        bcopy(cp, nfsd->nfsd_verfstr, 3 * NFSX_UNSIGNED);
                        nfsd->nfsd_verflen = 3 * NFSX_UNSIGNED;
                        nd->nd_flag |= ND_KERBFULL;
                        nfsd->nfsd_flag |= NFSD_NEEDAUTH;
                        break;
                case RPCAKN_NICKNAME:
                        if (len != 2 * NFSX_UNSIGNED) {
                                printf("Kerb nickname short\n");
                                nd->nd_repstat = (NFSERR_AUTHERR|AUTH_BADCRED);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        nickuid = fxdr_unsigned(uid_t, *tl);
                        nfsm_dissect(tl, u_long *, 2 * NFSX_UNSIGNED);
                        if (*tl++ != rpc_auth_kerb ||
                                fxdr_unsigned(int, *tl) != 3 * NFSX_UNSIGNED) {
                                printf("Kerb nick verifier bad\n");
                                nd->nd_repstat = (NFSERR_AUTHERR|AUTH_BADVERF);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        nfsm_dissect(tl, u_long *, 3 * NFSX_UNSIGNED);
                        tvin.tv_sec = *tl++;
                        tvin.tv_usec = *tl;

                        for (nuidp = NUIDHASH(nfsd->nfsd_slp,nickuid)->lh_first;
                            nuidp != 0; nuidp = nuidp->nu_hash.le_next) {
                                if (kauth_cred_getuid(nuidp->nu_cr) == nickuid &&
                                    (!nd->nd_nam2 ||
                                     netaddr_match(NU_NETFAM(nuidp),
                                      &nuidp->nu_haddr, nd->nd_nam2)))
                                        break;
                        }
                        if (!nuidp) {
                                nd->nd_repstat =
                                        (NFSERR_AUTHERR|AUTH_REJECTCRED);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }

                        /*
                         * Now, decrypt the timestamp using the session key
                         * and validate it.
                         */
#if NFSKERB
                        XXX
#endif

                        tvout.tv_sec = fxdr_unsigned(long, tvout.tv_sec);
                        tvout.tv_usec = fxdr_unsigned(long, tvout.tv_usec);
                        microtime(&now);
                        if (nuidp->nu_expire < now.tv_sec ||
                            nuidp->nu_timestamp.tv_sec > tvout.tv_sec ||
                            (nuidp->nu_timestamp.tv_sec == tvout.tv_sec &&
                             nuidp->nu_timestamp.tv_usec > tvout.tv_usec)) {
                                nuidp->nu_expire = 0;
                                nd->nd_repstat =
                                    (NFSERR_AUTHERR|AUTH_REJECTVERF);
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        bzero(&temp_cred, sizeof(temp_cred));
                        ngroups = nuidp->nu_cr->cr_ngroups;
                        for (i = 0; i < ngroups; i++)
                                temp_cred.cr_groups[i] = nuidp->nu_cr->cr_groups[i];
                        if (ngroups > 1)
                                nfsrvw_sort(&temp_cred.cr_groups[0], ngroups);

                        temp_cred.cr_uid = kauth_cred_getuid(nuidp->nu_cr);
                        temp_cred.cr_ngroups = ngroups;
                        nd->nd_cr = kauth_cred_create(&temp_cred); 
                        if (!nd->nd_cr) {
                                nd->nd_repstat = ENOMEM;
                                nd->nd_procnum = NFSPROC_NOOP;
                                return (0);
                        }
                        nd->nd_flag |= ND_KERBNICK;
                };
        } else {
                nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
                nd->nd_procnum = NFSPROC_NOOP;
                return (0);
        }

        nd->nd_md = md;
        nd->nd_dpos = dpos;
        return (0);
nfsmout:
        if (nd->nd_cr)
                kauth_cred_rele(nd->nd_cr);
        return (error);
}

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

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

        lck_rw_lock_exclusive(&slp->ns_rwlock);

        if (nfsd_waiting) {
                TAILQ_FOREACH(nd, &nfsd_head, nfsd_chain) {
                        if (nd->nfsd_flag & NFSD_WAITING) {
                                nd->nfsd_flag &= ~NFSD_WAITING;
                                if (nd->nfsd_slp)
                                        panic("nfsd wakeup");
                                slp->ns_sref++;
                                nd->nfsd_slp = slp;
                                lck_rw_done(&slp->ns_rwlock);
                                wakeup((caddr_t)nd);
                                return;
                        }
                }
        }

        slp->ns_flag |= SLP_DOREC;

        lck_rw_done(&slp->ns_rwlock);

        nfsd_head_flag |= NFSD_CHECKSLP;
}
#endif /* NFS_NOSERVER */

static int
nfs_msg(proc_t p,
        const char *server,
        const char *msg,
        int error)
{
        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);
}

void
nfs_down(nmp, proc, error, flags, msg)
        struct nfsmount *nmp;
        proc_t proc;
        int error, flags;
        const char *msg;
{
        if (nmp == NULL)
                return;
        if ((flags & NFSSTA_TIMEO) && !(nmp->nm_state & NFSSTA_TIMEO)) {
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, VQ_NOTRESP, 0);
                nmp->nm_state |= NFSSTA_TIMEO;
        }
        if ((flags & NFSSTA_LOCKTIMEO) && !(nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, VQ_NOTRESPLOCK, 0);
                nmp->nm_state |= NFSSTA_LOCKTIMEO;
        }
        nfs_msg(proc, vfs_statfs(nmp->nm_mountp)->f_mntfromname, msg, error);
}

void
nfs_up(nmp, proc, flags, msg)
        struct nfsmount *nmp;
        proc_t proc;
        int flags;
        const char *msg;
{
        if (nmp == NULL)
                return;
        if (msg)
                nfs_msg(proc, vfs_statfs(nmp->nm_mountp)->f_mntfromname, msg, 0);
        if ((flags & NFSSTA_TIMEO) && (nmp->nm_state & NFSSTA_TIMEO)) {
                nmp->nm_state &= ~NFSSTA_TIMEO;
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, VQ_NOTRESP, 1);
        }
        if ((flags & NFSSTA_LOCKTIMEO) && (nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                nmp->nm_state &= ~NFSSTA_LOCKTIMEO;
                vfs_event_signal(&vfs_statfs(nmp->nm_mountp)->f_fsid, VQ_NOTRESPLOCK, 1);
        }
}