xnu-7195.81.3.tar.gz

[apple/xnu.git] / bsd / kern / kpi_socket.c

/*
 * Copyright (c) 2003-2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#define __KPI__
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/mbuf.h>
#include <sys/mcache.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/uio_internal.h>
#include <kern/locks.h>
#include <net/net_api_stats.h>
#include <netinet/in.h>
#include <libkern/OSAtomic.h>
#include <stdbool.h>

static errno_t sock_send_internal(socket_t, const struct msghdr *,
    mbuf_t, int, size_t *);

#undef sock_accept
#undef sock_socket
errno_t sock_accept(socket_t so, struct sockaddr *from, int fromlen,
    int flags, sock_upcall callback, void *cookie, socket_t *new_so);
errno_t sock_socket(int domain, int type, int protocol, sock_upcall callback,
    void *context, socket_t *new_so);

static errno_t sock_accept_common(socket_t sock, struct sockaddr *from,
    int fromlen, int flags, sock_upcall callback, void *cookie,
    socket_t *new_sock, bool is_internal);
static errno_t sock_socket_common(int domain, int type, int protocol,
    sock_upcall callback, void *context, socket_t *new_so, bool is_internal);

errno_t
sock_accept_common(socket_t sock, struct sockaddr *from, int fromlen, int flags,
    sock_upcall callback, void *cookie, socket_t *new_sock, bool is_internal)
{
        struct sockaddr *sa;
        struct socket *new_so;
        lck_mtx_t *mutex_held;
        int dosocklock;
        errno_t error = 0;

        if (sock == NULL || new_sock == NULL) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        if ((sock->so_options & SO_ACCEPTCONN) == 0) {
                socket_unlock(sock, 1);
                return EINVAL;
        }
        if ((flags & ~(MSG_DONTWAIT)) != 0) {
                socket_unlock(sock, 1);
                return ENOTSUP;
        }
check_again:
        if (((flags & MSG_DONTWAIT) != 0 || (sock->so_state & SS_NBIO) != 0) &&
            sock->so_comp.tqh_first == NULL) {
                socket_unlock(sock, 1);
                return EWOULDBLOCK;
        }

        if (sock->so_proto->pr_getlock != NULL) {
                mutex_held = (*sock->so_proto->pr_getlock)(sock, PR_F_WILLUNLOCK);
                dosocklock = 1;
        } else {
                mutex_held = sock->so_proto->pr_domain->dom_mtx;
                dosocklock = 0;
        }

        while (TAILQ_EMPTY(&sock->so_comp) && sock->so_error == 0) {
                if (sock->so_state & SS_CANTRCVMORE) {
                        sock->so_error = ECONNABORTED;
                        break;
                }
                error = msleep((caddr_t)&sock->so_timeo, mutex_held,
                    PSOCK | PCATCH, "sock_accept", NULL);
                if (error != 0) {
                        socket_unlock(sock, 1);
                        return error;
                }
        }
        if (sock->so_error != 0) {
                error = sock->so_error;
                sock->so_error = 0;
                socket_unlock(sock, 1);
                return error;
        }

        so_acquire_accept_list(sock, NULL);
        if (TAILQ_EMPTY(&sock->so_comp)) {
                so_release_accept_list(sock);
                goto check_again;
        }
        new_so = TAILQ_FIRST(&sock->so_comp);
        TAILQ_REMOVE(&sock->so_comp, new_so, so_list);
        new_so->so_state &= ~SS_COMP;
        new_so->so_head = NULL;
        sock->so_qlen--;

        so_release_accept_list(sock);

        /*
         * Count the accepted socket as an in-kernel socket
         */
        new_so->so_flags1 |= SOF1_IN_KERNEL_SOCKET;
        INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_in_kernel_total);
        if (is_internal) {
                INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_in_kernel_os_total);
        }

        /*
         * Pass the pre-accepted socket to any interested socket filter(s).
         * Upon failure, the socket would have been closed by the callee.
         */
        if (new_so->so_filt != NULL) {
                /*
                 * Temporarily drop the listening socket's lock before we
                 * hand off control over to the socket filter(s), but keep
                 * a reference so that it won't go away.  We'll grab it
                 * again once we're done with the filter(s).
                 */
                socket_unlock(sock, 0);
                if ((error = soacceptfilter(new_so, sock)) != 0) {
                        /* Drop reference on listening socket */
                        sodereference(sock);
                        return error;
                }
                socket_lock(sock, 0);
        }

        if (dosocklock) {
                LCK_MTX_ASSERT(new_so->so_proto->pr_getlock(new_so, 0),
                    LCK_MTX_ASSERT_NOTOWNED);
                socket_lock(new_so, 1);
        }

        (void) soacceptlock(new_so, &sa, 0);

        socket_unlock(sock, 1); /* release the head */

        /* see comments in sock_setupcall() */
        if (callback != NULL) {
#if (defined(__arm__) || defined(__arm64__))
                sock_setupcalls_locked(new_so, callback, cookie, callback, cookie, 0);
#else /* (defined(__arm__) || defined(__arm64__)) */
                sock_setupcalls_locked(new_so, callback, cookie, NULL, NULL, 0);
#endif /* (defined(__arm__) || defined(__arm64__)) */
        }

        if (sa != NULL && from != NULL) {
                if (fromlen > sa->sa_len) {
                        fromlen = sa->sa_len;
                }
                memcpy(from, sa, fromlen);
        }
        if (sa != NULL) {
                FREE(sa, M_SONAME);
        }

        /*
         * If the socket has been marked as inactive by sosetdefunct(),
         * disallow further operations on it.
         */
        if (new_so->so_flags & SOF_DEFUNCT) {
                (void) sodefunct(current_proc(), new_so,
                    SHUTDOWN_SOCKET_LEVEL_DISCONNECT_INTERNAL);
        }
        *new_sock = new_so;
        if (dosocklock) {
                socket_unlock(new_so, 1);
        }
        return error;
}

errno_t
sock_accept(socket_t sock, struct sockaddr *from, int fromlen, int flags,
    sock_upcall callback, void *cookie, socket_t *new_sock)
{
        return sock_accept_common(sock, from, fromlen, flags,
                   callback, cookie, new_sock, false);
}

errno_t
sock_accept_internal(socket_t sock, struct sockaddr *from, int fromlen, int flags,
    sock_upcall callback, void *cookie, socket_t *new_sock)
{
        return sock_accept_common(sock, from, fromlen, flags,
                   callback, cookie, new_sock, true);
}

errno_t
sock_bind(socket_t sock, const struct sockaddr *to)
{
        int error = 0;
        struct sockaddr *sa = NULL;
        struct sockaddr_storage ss;
        boolean_t want_free = TRUE;

        if (sock == NULL || to == NULL) {
                return EINVAL;
        }

        if (to->sa_len > sizeof(ss)) {
                MALLOC(sa, struct sockaddr *, to->sa_len, M_SONAME, M_WAITOK);
                if (sa == NULL) {
                        return ENOBUFS;
                }
        } else {
                sa = (struct sockaddr *)&ss;
                want_free = FALSE;
        }
        memcpy(sa, to, to->sa_len);

        error = sobindlock(sock, sa, 1);        /* will lock socket */

        if (sa != NULL && want_free == TRUE) {
                FREE(sa, M_SONAME);
        }

        return error;
}

errno_t
sock_connect(socket_t sock, const struct sockaddr *to, int flags)
{
        int error = 0;
        lck_mtx_t *mutex_held;
        struct sockaddr *sa = NULL;
        struct sockaddr_storage ss;
        boolean_t want_free = TRUE;

        if (sock == NULL || to == NULL) {
                return EINVAL;
        }

        if (to->sa_len > sizeof(ss)) {
                MALLOC(sa, struct sockaddr *, to->sa_len, M_SONAME,
                    (flags & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK);
                if (sa == NULL) {
                        return ENOBUFS;
                }
        } else {
                sa = (struct sockaddr *)&ss;
                want_free = FALSE;
        }
        memcpy(sa, to, to->sa_len);

        socket_lock(sock, 1);

        if ((sock->so_state & SS_ISCONNECTING) &&
            ((sock->so_state & SS_NBIO) != 0 || (flags & MSG_DONTWAIT) != 0)) {
                error = EALREADY;
                goto out;
        }
        error = soconnectlock(sock, sa, 0);
        if (!error) {
                if ((sock->so_state & SS_ISCONNECTING) &&
                    ((sock->so_state & SS_NBIO) != 0 ||
                    (flags & MSG_DONTWAIT) != 0)) {
                        error = EINPROGRESS;
                        goto out;
                }

                if (sock->so_proto->pr_getlock != NULL) {
                        mutex_held = (*sock->so_proto->pr_getlock)(sock, PR_F_WILLUNLOCK);
                } else {
                        mutex_held = sock->so_proto->pr_domain->dom_mtx;
                }

                while ((sock->so_state & SS_ISCONNECTING) &&
                    sock->so_error == 0) {
                        error = msleep((caddr_t)&sock->so_timeo,
                            mutex_held, PSOCK | PCATCH, "sock_connect", NULL);
                        if (error != 0) {
                                break;
                        }
                }

                if (error == 0) {
                        error = sock->so_error;
                        sock->so_error = 0;
                }
        } else {
                sock->so_state &= ~SS_ISCONNECTING;
        }
out:
        socket_unlock(sock, 1);

        if (sa != NULL && want_free == TRUE) {
                FREE(sa, M_SONAME);
        }

        return error;
}

errno_t
sock_connectwait(socket_t sock, const struct timeval *tv)
{
        lck_mtx_t *mutex_held;
        errno_t retval = 0;
        struct timespec ts;

        socket_lock(sock, 1);

        /* Check if we're already connected or if we've already errored out */
        if ((sock->so_state & SS_ISCONNECTING) == 0 || sock->so_error != 0) {
                if (sock->so_error != 0) {
                        retval = sock->so_error;
                        sock->so_error = 0;
                } else {
                        if ((sock->so_state & SS_ISCONNECTED) != 0) {
                                retval = 0;
                        } else {
                                retval = EINVAL;
                        }
                }
                goto done;
        }

        /* copied translation from timeval to hertz from SO_RCVTIMEO handling */
        if (tv->tv_sec < 0 || tv->tv_sec > SHRT_MAX / hz ||
            tv->tv_usec < 0 || tv->tv_usec >= 1000000) {
                retval = EDOM;
                goto done;
        }

        ts.tv_sec = tv->tv_sec;
        ts.tv_nsec = (tv->tv_usec * (integer_t)NSEC_PER_USEC);
        if ((ts.tv_sec + (ts.tv_nsec / (long)NSEC_PER_SEC)) / 100 > SHRT_MAX) {
                retval = EDOM;
                goto done;
        }

        if (sock->so_proto->pr_getlock != NULL) {
                mutex_held = (*sock->so_proto->pr_getlock)(sock, PR_F_WILLUNLOCK);
        } else {
                mutex_held = sock->so_proto->pr_domain->dom_mtx;
        }

        msleep((caddr_t)&sock->so_timeo, mutex_held,
            PSOCK, "sock_connectwait", &ts);

        /* Check if we're still waiting to connect */
        if ((sock->so_state & SS_ISCONNECTING) && sock->so_error == 0) {
                retval = EINPROGRESS;
                goto done;
        }

        if (sock->so_error != 0) {
                retval = sock->so_error;
                sock->so_error = 0;
        }

done:
        socket_unlock(sock, 1);
        return retval;
}

errno_t
sock_nointerrupt(socket_t sock, int on)
{
        socket_lock(sock, 1);

        if (on) {
                sock->so_rcv.sb_flags |= SB_NOINTR;     /* This isn't safe */
                sock->so_snd.sb_flags |= SB_NOINTR;     /* This isn't safe */
        } else {
                sock->so_rcv.sb_flags &= ~SB_NOINTR;    /* This isn't safe */
                sock->so_snd.sb_flags &= ~SB_NOINTR;    /* This isn't safe */
        }

        socket_unlock(sock, 1);

        return 0;
}

errno_t
sock_getpeername(socket_t sock, struct sockaddr *peername, int peernamelen)
{
        int error;
        struct sockaddr *sa = NULL;

        if (sock == NULL || peername == NULL || peernamelen < 0) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        if (!(sock->so_state & (SS_ISCONNECTED | SS_ISCONFIRMING))) {
                socket_unlock(sock, 1);
                return ENOTCONN;
        }
        error = sogetaddr_locked(sock, &sa, 1);
        socket_unlock(sock, 1);
        if (error == 0) {
                if (peernamelen > sa->sa_len) {
                        peernamelen = sa->sa_len;
                }
                memcpy(peername, sa, peernamelen);
                FREE(sa, M_SONAME);
        }
        return error;
}

errno_t
sock_getsockname(socket_t sock, struct sockaddr *sockname, int socknamelen)
{
        int error;
        struct sockaddr *sa = NULL;

        if (sock == NULL || sockname == NULL || socknamelen < 0) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        error = sogetaddr_locked(sock, &sa, 0);
        socket_unlock(sock, 1);
        if (error == 0) {
                if (socknamelen > sa->sa_len) {
                        socknamelen = sa->sa_len;
                }
                memcpy(sockname, sa, socknamelen);
                FREE(sa, M_SONAME);
        }
        return error;
}

__private_extern__ int
sogetaddr_locked(struct socket *so, struct sockaddr **psa, int peer)
{
        int error;

        if (so == NULL || psa == NULL) {
                return EINVAL;
        }

        *psa = NULL;
        error = peer ? so->so_proto->pr_usrreqs->pru_peeraddr(so, psa) :
            so->so_proto->pr_usrreqs->pru_sockaddr(so, psa);

        if (error == 0 && *psa == NULL) {
                error = ENOMEM;
        } else if (error != 0 && *psa != NULL) {
                FREE(*psa, M_SONAME);
                *psa = NULL;
        }
        return error;
}

errno_t
sock_getaddr(socket_t sock, struct sockaddr **psa, int peer)
{
        int error;

        if (sock == NULL || psa == NULL) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        error = sogetaddr_locked(sock, psa, peer);
        socket_unlock(sock, 1);

        return error;
}

void
sock_freeaddr(struct sockaddr *sa)
{
        if (sa != NULL) {
                FREE(sa, M_SONAME);
        }
}

errno_t
sock_getsockopt(socket_t sock, int level, int optname, void *optval,
    int *optlen)
{
        int error = 0;
        struct sockopt  sopt;

        if (sock == NULL || optval == NULL || optlen == NULL) {
                return EINVAL;
        }

        sopt.sopt_dir = SOPT_GET;
        sopt.sopt_level = level;
        sopt.sopt_name = optname;
        sopt.sopt_val = CAST_USER_ADDR_T(optval);
        sopt.sopt_valsize = *optlen;
        sopt.sopt_p = kernproc;
        error = sogetoptlock(sock, &sopt, 1);   /* will lock socket */
        if (error == 0) {
                *optlen = (uint32_t)sopt.sopt_valsize;
        }
        return error;
}

errno_t
sock_ioctl(socket_t sock, unsigned long request, void *argp)
{
        return soioctl(sock, request, argp, kernproc); /* will lock socket */
}

errno_t
sock_setsockopt(socket_t sock, int level, int optname, const void *optval,
    int optlen)
{
        struct sockopt  sopt;

        if (sock == NULL || optval == NULL) {
                return EINVAL;
        }

        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_level = level;
        sopt.sopt_name = optname;
        sopt.sopt_val = CAST_USER_ADDR_T(optval);
        sopt.sopt_valsize = optlen;
        sopt.sopt_p = kernproc;
        return sosetoptlock(sock, &sopt, 1); /* will lock socket */
}

/*
 * This follows the recommended mappings between DSCP code points
 * and WMM access classes.
 */
static uint32_t
so_tc_from_dscp(uint8_t dscp)
{
        uint32_t tc;

        if (dscp >= 0x30 && dscp <= 0x3f) {
                tc = SO_TC_VO;
        } else if (dscp >= 0x20 && dscp <= 0x2f) {
                tc = SO_TC_VI;
        } else if (dscp >= 0x08 && dscp <= 0x17) {
                tc = SO_TC_BK_SYS;
        } else {
                tc = SO_TC_BE;
        }

        return tc;
}

errno_t
sock_settclassopt(socket_t sock, const void *optval, size_t optlen)
{
        errno_t error = 0;
        struct sockopt sopt;
        int sotc;

        if (sock == NULL || optval == NULL || optlen != sizeof(int)) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        if (!(sock->so_state & SS_ISCONNECTED)) {
                /*
                 * If the socket is not connected then we don't know
                 * if the destination is on LAN  or not. Skip
                 * setting traffic class in this case
                 */
                error = ENOTCONN;
                goto out;
        }

        if (sock->so_proto == NULL || sock->so_proto->pr_domain == NULL ||
            sock->so_pcb == NULL) {
                error = EINVAL;
                goto out;
        }

        /*
         * Set the socket traffic class based on the passed DSCP code point
         * regardless of the scope of the destination
         */
        sotc = so_tc_from_dscp((uint8_t)((*(const int *)optval) >> 2));

        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_val = CAST_USER_ADDR_T(&sotc);
        sopt.sopt_valsize = sizeof(sotc);
        sopt.sopt_p = kernproc;
        sopt.sopt_level = SOL_SOCKET;
        sopt.sopt_name = SO_TRAFFIC_CLASS;

        error = sosetoptlock(sock, &sopt, 0);   /* already locked */

        if (error != 0) {
                printf("%s: sosetopt SO_TRAFFIC_CLASS failed %d\n",
                    __func__, error);
                goto out;
        }

        /*
         * Check if the destination address is LAN or link local address.
         * We do not want to set traffic class bits if the destination
         * is not local.
         */
        if (!so_isdstlocal(sock)) {
                goto out;
        }

        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_val = CAST_USER_ADDR_T(optval);
        sopt.sopt_valsize = optlen;
        sopt.sopt_p = kernproc;

        switch (SOCK_DOM(sock)) {
        case PF_INET:
                sopt.sopt_level = IPPROTO_IP;
                sopt.sopt_name = IP_TOS;
                break;
        case PF_INET6:
                sopt.sopt_level = IPPROTO_IPV6;
                sopt.sopt_name = IPV6_TCLASS;
                break;
        default:
                error = EINVAL;
                goto out;
        }

        error = sosetoptlock(sock, &sopt, 0);   /* already locked */
        socket_unlock(sock, 1);
        return error;
out:
        socket_unlock(sock, 1);
        return error;
}

errno_t
sock_gettclassopt(socket_t sock, void *optval, size_t *optlen)
{
        errno_t error = 0;
        struct sockopt sopt;

        if (sock == NULL || optval == NULL || optlen == NULL) {
                return EINVAL;
        }

        sopt.sopt_dir = SOPT_GET;
        sopt.sopt_val = CAST_USER_ADDR_T(optval);
        sopt.sopt_valsize = *optlen;
        sopt.sopt_p = kernproc;

        socket_lock(sock, 1);
        if (sock->so_proto == NULL || sock->so_proto->pr_domain == NULL) {
                socket_unlock(sock, 1);
                return EINVAL;
        }

        switch (SOCK_DOM(sock)) {
        case PF_INET:
                sopt.sopt_level = IPPROTO_IP;
                sopt.sopt_name = IP_TOS;
                break;
        case PF_INET6:
                sopt.sopt_level = IPPROTO_IPV6;
                sopt.sopt_name = IPV6_TCLASS;
                break;
        default:
                socket_unlock(sock, 1);
                return EINVAL;
        }
        error = sogetoptlock(sock, &sopt, 0);   /* already locked */
        socket_unlock(sock, 1);
        if (error == 0) {
                *optlen = sopt.sopt_valsize;
        }
        return error;
}

errno_t
sock_listen(socket_t sock, int backlog)
{
        if (sock == NULL) {
                return EINVAL;
        }

        return solisten(sock, backlog); /* will lock socket */
}

errno_t
sock_receive_internal(socket_t sock, struct msghdr *msg, mbuf_t *data,
    int flags, size_t *recvdlen)
{
        uio_t auio;
        struct mbuf *control = NULL;
        int error = 0;
        user_ssize_t length = 0;
        struct sockaddr *fromsa = NULL;
        char uio_buf[UIO_SIZEOF((msg != NULL) ? msg->msg_iovlen : 0)];

        if (sock == NULL) {
                return EINVAL;
        }

        auio = uio_createwithbuffer(((msg != NULL) ? msg->msg_iovlen : 0),
            0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
        if (msg != NULL && data == NULL) {
                int i;
                struct iovec *tempp = msg->msg_iov;

                for (i = 0; i < msg->msg_iovlen; i++) {
                        uio_addiov(auio,
                            CAST_USER_ADDR_T((tempp + i)->iov_base),
                            (tempp + i)->iov_len);
                }
                if (uio_resid(auio) < 0) {
                        return EINVAL;
                }
        } else if (recvdlen != NULL) {
                uio_setresid(auio, (uio_resid(auio) + *recvdlen));
        }
        length = uio_resid(auio);

        if (recvdlen != NULL) {
                *recvdlen = 0;
        }

        /* let pru_soreceive handle the socket locking */
        error = sock->so_proto->pr_usrreqs->pru_soreceive(sock, &fromsa, auio,
            data, (msg && msg->msg_control) ? &control : NULL, &flags);
        if (error != 0) {
                goto cleanup;
        }

        if (recvdlen != NULL) {
                *recvdlen = length - uio_resid(auio);
        }
        if (msg != NULL) {
                msg->msg_flags = flags;

                if (msg->msg_name != NULL) {
                        int salen;
                        salen = msg->msg_namelen;
                        if (msg->msg_namelen > 0 && fromsa != NULL) {
                                salen = MIN(salen, fromsa->sa_len);
                                memcpy(msg->msg_name, fromsa,
                                    msg->msg_namelen > fromsa->sa_len ?
                                    fromsa->sa_len : msg->msg_namelen);
                        }
                }

                if (msg->msg_control != NULL) {
                        struct mbuf *m = control;
                        u_char *ctlbuf = msg->msg_control;
                        int clen = msg->msg_controllen;

                        msg->msg_controllen = 0;

                        while (m != NULL && clen > 0) {
                                unsigned int tocopy;

                                if (clen >= m->m_len) {
                                        tocopy = m->m_len;
                                } else {
                                        msg->msg_flags |= MSG_CTRUNC;
                                        tocopy = clen;
                                }
                                memcpy(ctlbuf, mtod(m, caddr_t), tocopy);
                                ctlbuf += tocopy;
                                clen -= tocopy;
                                m = m->m_next;
                        }
                        msg->msg_controllen =
                            (socklen_t)((uintptr_t)ctlbuf - (uintptr_t)msg->msg_control);
                }
        }

cleanup:
        if (control != NULL) {
                m_freem(control);
        }
        if (fromsa != NULL) {
                FREE(fromsa, M_SONAME);
        }
        return error;
}

errno_t
sock_receive(socket_t sock, struct msghdr *msg, int flags, size_t *recvdlen)
{
        if ((msg == NULL) || (msg->msg_iovlen < 1) ||
            (msg->msg_iov[0].iov_len == 0) ||
            (msg->msg_iov[0].iov_base == NULL)) {
                return EINVAL;
        }

        return sock_receive_internal(sock, msg, NULL, flags, recvdlen);
}

errno_t
sock_receivembuf(socket_t sock, struct msghdr *msg, mbuf_t *data, int flags,
    size_t *recvlen)
{
        if (data == NULL || recvlen == 0 || *recvlen <= 0 || (msg != NULL &&
            (msg->msg_iov != NULL || msg->msg_iovlen != 0))) {
                return EINVAL;
        }

        return sock_receive_internal(sock, msg, data, flags, recvlen);
}

errno_t
sock_send_internal(socket_t sock, const struct msghdr *msg, mbuf_t data,
    int flags, size_t *sentlen)
{
        uio_t auio = NULL;
        struct mbuf *control = NULL;
        int error = 0;
        user_ssize_t datalen = 0;
        char uio_buf[UIO_SIZEOF((msg != NULL ? msg->msg_iovlen : 1))];

        if (sock == NULL) {
                error = EINVAL;
                goto errorout;
        }

        if (data == NULL && msg != NULL) {
                struct iovec *tempp = msg->msg_iov;

                auio = uio_createwithbuffer(msg->msg_iovlen, 0,
                    UIO_SYSSPACE, UIO_WRITE, &uio_buf[0], sizeof(uio_buf));
                if (tempp != NULL) {
                        int i;

                        for (i = 0; i < msg->msg_iovlen; i++) {
                                uio_addiov(auio,
                                    CAST_USER_ADDR_T((tempp + i)->iov_base),
                                    (tempp + i)->iov_len);
                        }

                        if (uio_resid(auio) < 0) {
                                error = EINVAL;
                                goto errorout;
                        }
                }
        }

        if (sentlen != NULL) {
                *sentlen = 0;
        }

        if (auio != NULL) {
                datalen = uio_resid(auio);
        } else {
                datalen = data->m_pkthdr.len;
        }

        if (msg != NULL && msg->msg_control) {
                if ((size_t)msg->msg_controllen < sizeof(struct cmsghdr)) {
                        error = EINVAL;
                        goto errorout;
                }

                if ((size_t)msg->msg_controllen > MLEN) {
                        error = EINVAL;
                        goto errorout;
                }

                control = m_get(M_NOWAIT, MT_CONTROL);
                if (control == NULL) {
                        error = ENOMEM;
                        goto errorout;
                }
                memcpy(mtod(control, caddr_t), msg->msg_control,
                    msg->msg_controllen);
                control->m_len = msg->msg_controllen;
        }

        error = sock->so_proto->pr_usrreqs->pru_sosend(sock, msg != NULL ?
            (struct sockaddr *)msg->msg_name : NULL, auio, data,
            control, flags);

        /*
         * Residual data is possible in the case of IO vectors but not
         * in the mbuf case since the latter is treated as atomic send.
         * If pru_sosend() consumed a portion of the iovecs data and
         * the error returned is transient, treat it as success; this
         * is consistent with sendit() behavior.
         */
        if (auio != NULL && uio_resid(auio) != datalen &&
            (error == ERESTART || error == EINTR || error == EWOULDBLOCK)) {
                error = 0;
        }

        if (error == 0 && sentlen != NULL) {
                if (auio != NULL) {
                        *sentlen = datalen - uio_resid(auio);
                } else {
                        *sentlen = datalen;
                }
        }

        return error;

/*
 * In cases where we detect an error before returning, we need to
 * free the mbuf chain if there is one. sosend (and pru_sosend) will
 * free the mbuf chain if they encounter an error.
 */
errorout:
        if (control) {
                m_freem(control);
        }
        if (data) {
                m_freem(data);
        }
        if (sentlen) {
                *sentlen = 0;
        }
        return error;
}

errno_t
sock_send(socket_t sock, const struct msghdr *msg, int flags, size_t *sentlen)
{
        if (msg == NULL || msg->msg_iov == NULL || msg->msg_iovlen < 1) {
                return EINVAL;
        }

        return sock_send_internal(sock, msg, NULL, flags, sentlen);
}

errno_t
sock_sendmbuf(socket_t sock, const struct msghdr *msg, mbuf_t data,
    int flags, size_t *sentlen)
{
        if (data == NULL || (msg != NULL && (msg->msg_iov != NULL ||
            msg->msg_iovlen != 0))) {
                if (data != NULL) {
                        m_freem(data);
                }
                return EINVAL;
        }
        return sock_send_internal(sock, msg, data, flags, sentlen);
}

errno_t
sock_shutdown(socket_t sock, int how)
{
        if (sock == NULL) {
                return EINVAL;
        }

        return soshutdown(sock, how);
}

errno_t
sock_socket_common(int domain, int type, int protocol, sock_upcall callback,
    void *context, socket_t *new_so, bool is_internal)
{
        int error = 0;

        if (new_so == NULL) {
                return EINVAL;
        }

        /* socreate will create an initial so_count */
        error = socreate(domain, new_so, type, protocol);
        if (error == 0) {
                /*
                 * This is an in-kernel socket
                 */
                (*new_so)->so_flags1 |= SOF1_IN_KERNEL_SOCKET;
                INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_in_kernel_total);
                if (is_internal) {
                        INC_ATOMIC_INT64_LIM(net_api_stats.nas_socket_in_kernel_os_total);
                }

                /* see comments in sock_setupcall() */
                if (callback != NULL) {
                        sock_setupcall(*new_so, callback, context);
                }
                /*
                 * last_pid and last_upid should be zero for sockets
                 * created using sock_socket
                 */
                (*new_so)->last_pid = 0;
                (*new_so)->last_upid = 0;
        }
        return error;
}

errno_t
sock_socket_internal(int domain, int type, int protocol, sock_upcall callback,
    void *context, socket_t *new_so)
{
        return sock_socket_common(domain, type, protocol, callback,
                   context, new_so, true);
}

errno_t
sock_socket(int domain, int type, int protocol, sock_upcall callback,
    void *context, socket_t *new_so)
{
        return sock_socket_common(domain, type, protocol, callback,
                   context, new_so, false);
}

void
sock_close(socket_t sock)
{
        if (sock == NULL) {
                return;
        }

        soclose(sock);
}

/* Do we want this to be APPLE_PRIVATE API?: YES (LD 12/23/04) */
void
sock_retain(socket_t sock)
{
        if (sock == NULL) {
                return;
        }

        socket_lock(sock, 1);
        sock->so_retaincnt++;
        sock->so_usecount++;    /* add extra reference for holding the socket */
        socket_unlock(sock, 1);
}

/* Do we want this to be APPLE_PRIVATE API? */
void
sock_release(socket_t sock)
{
        if (sock == NULL) {
                return;
        }

        socket_lock(sock, 1);
        if (sock->so_upcallusecount > 0) {
                soclose_wait_locked(sock);
        }

        sock->so_retaincnt--;
        if (sock->so_retaincnt < 0) {
                panic("%s: negative retain count (%d) for sock=%p\n",
                    __func__, sock->so_retaincnt, sock);
                /* NOTREACHED */
        }
        /*
         * Check SS_NOFDREF in case a close happened as sock_retain()
         * was grabbing the lock
         */
        if ((sock->so_retaincnt == 0) && (sock->so_usecount == 2) &&
            (!(sock->so_state & SS_NOFDREF) ||
            (sock->so_flags & SOF_MP_SUBFLOW))) {
                /* close socket only if the FD is not holding it */
                soclose_locked(sock);
        } else {
                /* remove extra reference holding the socket */
                VERIFY(sock->so_usecount > 1);
                sock->so_usecount--;
        }
        socket_unlock(sock, 1);
}

errno_t
sock_setpriv(socket_t sock, int on)
{
        if (sock == NULL) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        if (on) {
                sock->so_state |= SS_PRIV;
        } else {
                sock->so_state &= ~SS_PRIV;
        }
        socket_unlock(sock, 1);
        return 0;
}

int
sock_isconnected(socket_t sock)
{
        int retval;

        socket_lock(sock, 1);
        retval = ((sock->so_state & SS_ISCONNECTED) ? 1 : 0);
        socket_unlock(sock, 1);
        return retval;
}

int
sock_isnonblocking(socket_t sock)
{
        int retval;

        socket_lock(sock, 1);
        retval = ((sock->so_state & SS_NBIO) ? 1 : 0);
        socket_unlock(sock, 1);
        return retval;
}

errno_t
sock_gettype(socket_t sock, int *outDomain, int *outType, int *outProtocol)
{
        socket_lock(sock, 1);
        if (outDomain != NULL) {
                *outDomain = SOCK_DOM(sock);
        }
        if (outType != NULL) {
                *outType = sock->so_type;
        }
        if (outProtocol != NULL) {
                *outProtocol = SOCK_PROTO(sock);
        }
        socket_unlock(sock, 1);
        return 0;
}

/*
 * Return the listening socket of a pre-accepted socket.  It returns the
 * listener (so_head) value of a given socket.  This is intended to be
 * called by a socket filter during a filter attach (sf_attach) callback.
 * The value returned by this routine is safe to be used only in the
 * context of that callback, because we hold the listener's lock across
 * the sflt_initsock() call.
 */
socket_t
sock_getlistener(socket_t sock)
{
        return sock->so_head;
}

static inline void
sock_set_tcp_stream_priority(socket_t sock)
{
        if ((SOCK_DOM(sock) == PF_INET || SOCK_DOM(sock) == PF_INET6) &&
            SOCK_TYPE(sock) == SOCK_STREAM) {
                set_tcp_stream_priority(sock);
        }
}

/*
 * Caller must have ensured socket is valid and won't be going away.
 */
void
socket_set_traffic_mgt_flags_locked(socket_t sock, u_int8_t flags)
{
        u_int32_t soflags1 = 0;

        if ((flags & TRAFFIC_MGT_SO_BACKGROUND)) {
                soflags1 |= SOF1_TRAFFIC_MGT_SO_BACKGROUND;
        }
        if ((flags & TRAFFIC_MGT_TCP_RECVBG)) {
                soflags1 |= SOF1_TRAFFIC_MGT_TCP_RECVBG;
        }

        (void) OSBitOrAtomic(soflags1, &sock->so_flags1);

        sock_set_tcp_stream_priority(sock);
}

void
socket_set_traffic_mgt_flags(socket_t sock, u_int8_t flags)
{
        socket_lock(sock, 1);
        socket_set_traffic_mgt_flags_locked(sock, flags);
        socket_unlock(sock, 1);
}

/*
 * Caller must have ensured socket is valid and won't be going away.
 */
void
socket_clear_traffic_mgt_flags_locked(socket_t sock, u_int8_t flags)
{
        u_int32_t soflags1 = 0;

        if ((flags & TRAFFIC_MGT_SO_BACKGROUND)) {
                soflags1 |= SOF1_TRAFFIC_MGT_SO_BACKGROUND;
        }
        if ((flags & TRAFFIC_MGT_TCP_RECVBG)) {
                soflags1 |= SOF1_TRAFFIC_MGT_TCP_RECVBG;
        }

        (void) OSBitAndAtomic(~soflags1, &sock->so_flags1);

        sock_set_tcp_stream_priority(sock);
}

void
socket_clear_traffic_mgt_flags(socket_t sock, u_int8_t flags)
{
        socket_lock(sock, 1);
        socket_clear_traffic_mgt_flags_locked(sock, flags);
        socket_unlock(sock, 1);
}


/*
 * Caller must have ensured socket is valid and won't be going away.
 */
errno_t
socket_defunct(struct proc *p, socket_t so, int level)
{
        errno_t retval;

        if (level != SHUTDOWN_SOCKET_LEVEL_DISCONNECT_SVC &&
            level != SHUTDOWN_SOCKET_LEVEL_DISCONNECT_ALL) {
                return EINVAL;
        }

        socket_lock(so, 1);
        /*
         * SHUTDOWN_SOCKET_LEVEL_DISCONNECT_SVC level is meant to tear down
         * all of mDNSResponder IPC sockets, currently those of AF_UNIX; note
         * that this is an implementation artifact of mDNSResponder.  We do
         * a quick test against the socket buffers for SB_UNIX, since that
         * would have been set by unp_attach() at socket creation time.
         */
        if (level == SHUTDOWN_SOCKET_LEVEL_DISCONNECT_SVC &&
            (so->so_rcv.sb_flags & so->so_snd.sb_flags & SB_UNIX) != SB_UNIX) {
                socket_unlock(so, 1);
                return EOPNOTSUPP;
        }
        retval = sosetdefunct(p, so, level, TRUE);
        if (retval == 0) {
                retval = sodefunct(p, so, level);
        }
        socket_unlock(so, 1);
        return retval;
}

void
sock_setupcalls_locked(socket_t sock, sock_upcall rcallback, void *rcontext,
    sock_upcall wcallback, void *wcontext, int locked)
{
        if (rcallback != NULL) {
                sock->so_rcv.sb_flags |= SB_UPCALL;
                if (locked) {
                        sock->so_rcv.sb_flags |= SB_UPCALL_LOCK;
                }
                sock->so_rcv.sb_upcall = rcallback;
                sock->so_rcv.sb_upcallarg = rcontext;
        } else {
                sock->so_rcv.sb_flags &= ~(SB_UPCALL | SB_UPCALL_LOCK);
                sock->so_rcv.sb_upcall = NULL;
                sock->so_rcv.sb_upcallarg = NULL;
        }

        if (wcallback != NULL) {
                sock->so_snd.sb_flags |= SB_UPCALL;
                if (locked) {
                        sock->so_snd.sb_flags |= SB_UPCALL_LOCK;
                }
                sock->so_snd.sb_upcall = wcallback;
                sock->so_snd.sb_upcallarg = wcontext;
        } else {
                sock->so_snd.sb_flags &= ~(SB_UPCALL | SB_UPCALL_LOCK);
                sock->so_snd.sb_upcall = NULL;
                sock->so_snd.sb_upcallarg = NULL;
        }
}

errno_t
sock_setupcall(socket_t sock, sock_upcall callback, void *context)
{
        if (sock == NULL) {
                return EINVAL;
        }

        /*
         * Note that we don't wait for any in progress upcall to complete.
         * On embedded, sock_setupcall() causes both read and write
         * callbacks to be set; on desktop, only read callback is set
         * to maintain legacy KPI behavior.
         *
         * The newer sock_setupcalls() KPI should be used instead to set
         * the read and write callbacks and their respective parameters.
         */
        socket_lock(sock, 1);
#if (defined(__arm__) || defined(__arm64__))
        sock_setupcalls_locked(sock, callback, context, callback, context, 0);
#else /* (defined(__arm__) || defined(__arm64__)) */
        sock_setupcalls_locked(sock, callback, context, NULL, NULL, 0);
#endif /* (defined(__arm__) || defined(__arm64__)) */
        socket_unlock(sock, 1);

        return 0;
}

errno_t
sock_setupcalls(socket_t sock, sock_upcall rcallback, void *rcontext,
    sock_upcall wcallback, void *wcontext)
{
        if (sock == NULL) {
                return EINVAL;
        }

        /*
         * Note that we don't wait for any in progress upcall to complete.
         */
        socket_lock(sock, 1);
        sock_setupcalls_locked(sock, rcallback, rcontext, wcallback, wcontext, 0);
        socket_unlock(sock, 1);

        return 0;
}

void
sock_catchevents_locked(socket_t sock, sock_evupcall ecallback, void *econtext,
    long emask)
{
        socket_lock_assert_owned(sock);

        /*
         * Note that we don't wait for any in progress upcall to complete.
         */
        if (ecallback != NULL) {
                sock->so_event = ecallback;
                sock->so_eventarg = econtext;
                sock->so_eventmask = (uint32_t)emask;
        } else {
                sock->so_event = sonullevent;
                sock->so_eventarg = NULL;
                sock->so_eventmask = 0;
        }
}

errno_t
sock_catchevents(socket_t sock, sock_evupcall ecallback, void *econtext,
    long emask)
{
        if (sock == NULL) {
                return EINVAL;
        }

        socket_lock(sock, 1);
        sock_catchevents_locked(sock, ecallback, econtext, emask);
        socket_unlock(sock, 1);

        return 0;
}

/*
 * Returns true whether or not a socket belongs to the kernel.
 */
int
sock_iskernel(socket_t so)
{
        return so && so->last_pid == 0;
}