/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1988, 1990, 1993
 *      The Regents of the University of California.
 * Copyright (c) 2004 The FreeBSD Foundation
 * Copyright (c) 2004-2008 Robert N. M. Watson
 * All rights reserved.
 *
 * 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. 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.
 */

/*
 * Comments on the socket life cycle:
 *
 * soalloc() sets of socket layer state for a socket, called only by
 * socreate() and sonewconn().  Socket layer private.
 *
 * sodealloc() tears down socket layer state for a socket, called only by
 * sofree() and sonewconn().  Socket layer private.
 *
 * pr_attach() associates protocol layer state with an allocated socket;
 * called only once, may fail, aborting socket allocation.  This is called
 * from socreate() and sonewconn().  Socket layer private.
 *
 * pr_detach() disassociates protocol layer state from an attached socket,
 * and will be called exactly once for sockets in which pr_attach() has
 * been successfully called.  If pr_attach() returned an error,
 * pr_detach() will not be called.  Socket layer private.
 *
 * pr_abort() and pr_close() notify the protocol layer that the last
 * consumer of a socket is starting to tear down the socket, and that the
 * protocol should terminate the connection.  Historically, pr_abort() also
 * detached protocol state from the socket state, but this is no longer the
 * case.  pr_fdclose() is called when userspace invokes close(2) on a socket
 * file descriptor.
 *
 * socreate() creates a socket and attaches protocol state.  This is a public
 * interface that may be used by socket layer consumers to create new
 * sockets.
 *
 * sonewconn() creates a socket and attaches protocol state.  This is a
 * public interface  that may be used by protocols to create new sockets when
 * a new connection is received and will be available for accept() on a
 * listen socket.
 *
 * soclose() destroys a socket after possibly waiting for it to disconnect.
 * This is a public interface that socket consumers should use to close and
 * release a socket when done with it.
 *
 * soabort() destroys a socket without waiting for it to disconnect (used
 * only for incoming connections that are already partially or fully
 * connected).  This is used internally by the socket layer when clearing
 * listen socket queues (due to overflow or close on the listen socket), but
 * is also a public interface protocols may use to abort connections in
 * their incomplete listen queues should they no longer be required.  Sockets
 * placed in completed connection listen queues should not be aborted for
 * reasons described in the comment above the soclose() implementation.  This
 * is not a general purpose close routine, and except in the specific
 * circumstances described here, should not be used.
 *
 * sofree() will free a socket and its protocol state if all references on
 * the socket have been released, and is the public interface to attempt to
 * free a socket when a reference is removed.  This is a socket layer private
 * interface.
 *
 * NOTE: In addition to socreate() and soclose(), which provide a single
 * socket reference to the consumer to be managed as required, there are two
 * calls to explicitly manage socket references, soref(), and sorele().
 * Currently, these are generally required only when transitioning a socket
 * from a listen queue to a file descriptor, in order to prevent garbage
 * collection of the socket at an untimely moment.  For a number of reasons,
 * these interfaces are not preferred, and should be avoided.
 *
 * NOTE: With regard to VNETs the general rule is that callers do not set
 * curvnet. Exceptions to this rule include soabort(), sodisconnect(),
 * sofree(), sorele(), sonewconn() and sorflush(), which are usually called
 * from a pre-set VNET context.  sopoll_generic() currently does not need a
 * VNET context to be set.
 */

#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_kern_tls.h"
#include "opt_ktrace.h"
#include "opt_sctp.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/fcntl.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/domain.h>
#include <sys/file.h>                   /* for struct knote */
#include <sys/hhook.h>
#include <sys/kernel.h>
#include <sys/khelp.h>
#include <sys/kthread.h>
#include <sys/ktls.h>
#include <sys/event.h>
#include <sys/eventhandler.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/resourcevar.h>
#include <net/route.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <sys/jail.h>
#include <sys/syslog.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp.h>

#include <net/vnet.h>

#include <security/mac/mac_framework.h>
#include <security/mac/mac_internal.h>

#include <vm/uma.h>

#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <sys/sysent.h>
#include <compat/freebsd32/freebsd32.h>
#endif

static int      soreceive_generic_locked(struct socket *so,
                    struct sockaddr **psa, struct uio *uio, struct mbuf **mp,
                    struct mbuf **controlp, int *flagsp);
static int      soreceive_rcvoob(struct socket *so, struct uio *uio,
                    int flags);
static int      soreceive_stream_locked(struct socket *so, struct sockbuf *sb,
                    struct sockaddr **psa, struct uio *uio, struct mbuf **mp,
                    struct mbuf **controlp, int flags);
static int      sosend_generic_locked(struct socket *so, struct sockaddr *addr,
                    struct uio *uio, struct mbuf *top, struct mbuf *control,
                    int flags, struct thread *td);
static void     so_rdknl_lock(void *);
static void     so_rdknl_unlock(void *);
static void     so_rdknl_assert_lock(void *, int);
static void     so_wrknl_lock(void *);
static void     so_wrknl_unlock(void *);
static void     so_wrknl_assert_lock(void *, int);

static void     filt_sordetach(struct knote *kn);
static int      filt_soread(struct knote *kn, long hint);
static void     filt_sowdetach(struct knote *kn);
static int      filt_sowrite(struct knote *kn, long hint);
static int      filt_soempty(struct knote *kn, long hint);

static const struct filterops soread_filtops = {
        .f_isfd = 1,
        .f_detach = filt_sordetach,
        .f_event = filt_soread,
        .f_copy = knote_triv_copy,
};
static const struct filterops sowrite_filtops = {
        .f_isfd = 1,
        .f_detach = filt_sowdetach,
        .f_event = filt_sowrite,
        .f_copy = knote_triv_copy,
};
static const struct filterops soempty_filtops = {
        .f_isfd = 1,
        .f_detach = filt_sowdetach,
        .f_event = filt_soempty,
        .f_copy = knote_triv_copy,
};

so_gen_t        so_gencnt;      /* generation count for sockets */

MALLOC_DEFINE(M_SONAME, "soname", "socket name");
MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");

#define VNET_SO_ASSERT(so)                                              \
        VNET_ASSERT(curvnet != NULL,                                    \
            ("%s:%d curvnet is NULL, so=%p", __func__, __LINE__, (so)));

#ifdef SOCKET_HHOOK
VNET_DEFINE(struct hhook_head *, socket_hhh[HHOOK_SOCKET_LAST + 1]);
#define V_socket_hhh            VNET(socket_hhh)
static inline int hhook_run_socket(struct socket *, void *, int32_t);
#endif

#ifdef COMPAT_FREEBSD32
#ifdef __amd64__
/* off_t has 4-byte alignment on i386 but not on other 32-bit platforms. */
#define __splice32_packed       __packed
#else
#define __splice32_packed
#endif
struct splice32 {
        int32_t sp_fd;
        int64_t sp_max;
        struct timeval32 sp_idle;
} __splice32_packed;
#undef __splice32_packed
#endif

/*
 * Limit on the number of connections in the listen queue waiting
 * for accept(2).
 * NB: The original sysctl somaxconn is still available but hidden
 * to prevent confusion about the actual purpose of this number.
 */
VNET_DEFINE_STATIC(u_int, somaxconn) = SOMAXCONN;
#define V_somaxconn     VNET(somaxconn)

static int
sysctl_somaxconn(SYSCTL_HANDLER_ARGS)
{
        int error;
        u_int val;

        val = V_somaxconn;
        error = sysctl_handle_int(oidp, &val, 0, req);
        if (error || !req->newptr )
                return (error);

        /*
         * The purpose of the UINT_MAX / 3 limit, is so that the formula
         *   3 * sol_qlimit / 2
         * below, will not overflow.
         */

        if (val < 1 || val > UINT_MAX / 3)
                return (EINVAL);

        V_somaxconn = val;
        return (0);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, soacceptqueue,
    CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE | CTLFLAG_VNET, 0, sizeof(u_int),
    sysctl_somaxconn, "IU",
    "Maximum listen socket pending connection accept queue size");
SYSCTL_PROC(_kern_ipc, KIPC_SOMAXCONN, somaxconn,
    CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE | CTLFLAG_VNET, 0,
    sizeof(u_int), sysctl_somaxconn, "IU",
    "Maximum listen socket pending connection accept queue size (compat)");

static u_int numopensockets;
static int
sysctl_numopensockets(SYSCTL_HANDLER_ARGS)
{
        u_int val;

#ifdef VIMAGE
        if(!IS_DEFAULT_VNET(curvnet))
                val = curvnet->vnet_sockcnt;
        else
#endif
                val = numopensockets;
        return (sysctl_handle_int(oidp, &val, 0, req));
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, numopensockets,
    CTLTYPE_UINT | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_VNET, 0, sizeof(u_int),
    sysctl_numopensockets, "IU", "Number of open sockets");

/*
 * so_global_mtx protects so_gencnt, numopensockets, and the per-socket
 * so_gencnt field.
 */
static struct mtx so_global_mtx;
MTX_SYSINIT(so_global_mtx, &so_global_mtx, "so_glabel", MTX_DEF);

/*
 * General IPC sysctl name space, used by sockets and a variety of other IPC
 * types.
 */
SYSCTL_NODE(_kern, KERN_IPC, ipc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "IPC");

/*
 * Initialize the socket subsystem and set up the socket
 * memory allocator.
 */
static uma_zone_t socket_zone;
int     maxsockets;

static void
socket_zone_change(void *tag)
{

        maxsockets = uma_zone_set_max(socket_zone, maxsockets);
}

static int splice_init_state;
static struct sx splice_init_lock;
SX_SYSINIT(splice_init_lock, &splice_init_lock, "splice_init");

static SYSCTL_NODE(_kern_ipc, OID_AUTO, splice, CTLFLAG_RW, 0,
    "Settings relating to the SO_SPLICE socket option");

static bool splice_receive_stream = true;
SYSCTL_BOOL(_kern_ipc_splice, OID_AUTO, receive_stream, CTLFLAG_RWTUN,
    &splice_receive_stream, 0,
    "Use soreceive_stream() for stream splices");

static int splice_num_wq = -1;
static int
sysctl_splice_num_wq(SYSCTL_HANDLER_ARGS)
{
        int error, new;

        new = splice_num_wq;
        error = sysctl_handle_int(oidp, &new, 0, req);
        if (error == 0 && req->newptr && new != splice_num_wq) {
                if (!cold)
                        sx_xlock(&splice_init_lock);
                if (new < -1 || new > mp_ncpus ||
                    (new <= 0 && splice_init_state != 0)) {
                        error = EINVAL;
                } else {
                        splice_num_wq = new;
                }
                if (!cold)
                        sx_xunlock(&splice_init_lock);
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc_splice, OID_AUTO, num_wq,
    CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
    &splice_num_wq, 0, sysctl_splice_num_wq, "IU",
    "Number of splice worker queues");

static uma_zone_t splice_zone;
static struct proc *splice_proc;
struct splice_wq {
        struct mtx      mtx;
        STAILQ_HEAD(, so_splice) head;
        bool            running;
} __aligned(CACHE_LINE_SIZE);
static struct splice_wq *splice_wq;
static uint32_t splice_index = 0;

static void so_splice_timeout(void *arg, int pending);
static void so_splice_xfer(struct so_splice *s);
static int so_unsplice(struct socket *so, bool timeout);

static void
splice_work_thread(void *ctx)
{
        struct splice_wq *wq = ctx;
        struct so_splice *s, *s_temp;
        STAILQ_HEAD(, so_splice) local_head;
        int cpu;

        cpu = wq - splice_wq;
        if (bootverbose)
                printf("starting so_splice worker thread for CPU %d\n", cpu);

        for (;;) {
                mtx_lock(&wq->mtx);
                while (STAILQ_EMPTY(&wq->head)) {
                        wq->running = false;
                        mtx_sleep(wq, &wq->mtx, 0, "-", 0);
                        wq->running = true;
                }
                STAILQ_INIT(&local_head);
                STAILQ_CONCAT(&local_head, &wq->head);
                STAILQ_INIT(&wq->head);
                mtx_unlock(&wq->mtx);
                STAILQ_FOREACH_SAFE(s, &local_head, next, s_temp) {
                        mtx_lock(&s->mtx);
                        CURVNET_SET(s->src->so_vnet);
                        so_splice_xfer(s);
                        CURVNET_RESTORE();
                }
        }
}

static void
so_splice_dispatch_async(struct so_splice *sp)
{
        struct splice_wq *wq;
        bool running;

        wq = &splice_wq[sp->wq_index];
        mtx_lock(&wq->mtx);
        STAILQ_INSERT_TAIL(&wq->head, sp, next);
        running = wq->running;
        mtx_unlock(&wq->mtx);
        if (!running)
                wakeup(wq);
}

void
so_splice_dispatch(struct so_splice *sp)
{
        mtx_assert(&sp->mtx, MA_OWNED);

        if (sp->state != SPLICE_IDLE) {
                mtx_unlock(&sp->mtx);
        } else {
                sp->state = SPLICE_QUEUED;
                mtx_unlock(&sp->mtx);
                so_splice_dispatch_async(sp);
        }
}

static int
splice_zinit(void *mem, int size __unused, int flags __unused)
{
        struct so_splice *s;

        s = (struct so_splice *)mem;
        mtx_init(&s->mtx, "so_splice", NULL, MTX_DEF);
        return (0);
}

static void
splice_zfini(void *mem, int size)
{
        struct so_splice *s;

        s = (struct so_splice *)mem;
        mtx_destroy(&s->mtx);
}

static int
splice_init(void)
{
        struct thread *td;
        int error, i, state;

        state = atomic_load_acq_int(&splice_init_state);
        if (__predict_true(state > 0))
                return (0);
        if (state < 0)
                return (ENXIO);
        sx_xlock(&splice_init_lock);
        if (splice_init_state != 0) {
                sx_xunlock(&splice_init_lock);
                return (0);
        }

        if (splice_num_wq == -1) {
                /* if no user preference, use all cores */
                splice_num_wq = mp_ncpus;
        } else if (splice_num_wq == 0) {
                /* allow user to disable */
                splice_init_state = -1;
                sx_xunlock(&splice_init_lock);
                return (ENXIO);
        } else if (splice_num_wq > mp_ncpus) {
                splice_num_wq = mp_ncpus;
        }

        splice_zone = uma_zcreate("splice", sizeof(struct so_splice), NULL,
            NULL, splice_zinit, splice_zfini, UMA_ALIGN_CACHE, 0);

        splice_wq = mallocarray(mp_ncpus, sizeof(*splice_wq), M_TEMP,
            M_WAITOK | M_ZERO);

        /*
         * Initialize the workqueues to run the splice work.  We create a
         * work queue for each CPU.
         */
        for (i = 0; i < mp_ncpus; i++) {
                STAILQ_INIT(&splice_wq[i].head);
                mtx_init(&splice_wq[i].mtx, "splice work queue", NULL, MTX_DEF);
        }

        /* Start kthreads for each workqueue. */
        error = 0;
        for (i = 0; i < mp_ncpus; i++) {
                error = kproc_kthread_add(splice_work_thread, &splice_wq[i],
                    &splice_proc, &td, 0, 0, "so_splice", "thr_%d", i);
                if (error) {
                        printf("Can't add so_splice thread %d error %d\n",
                            i, error);
                        break;
                }

                /*
                 * It's possible to create loops with SO_SPLICE; ensure that
                 * worker threads aren't able to starve the system too easily.
                 */
                thread_lock(td);
                sched_prio(td, PUSER);
                thread_unlock(td);
        }

        splice_init_state = error != 0 ? -1 : 1;
        sx_xunlock(&splice_init_lock);

        return (error);
}

/*
 * Lock a pair of socket's I/O locks for splicing.  Avoid blocking while holding
 * one lock in order to avoid potential deadlocks in case there is some other
 * code path which acquires more than one I/O lock at a time.
 */
static void
splice_lock_pair(struct socket *so_src, struct socket *so_dst)
{
        int error;

        for (;;) {
                error = SOCK_IO_SEND_LOCK(so_dst, SBL_WAIT | SBL_NOINTR);
                KASSERT(error == 0,
                    ("%s: failed to lock send I/O lock: %d", __func__, error));
                error = SOCK_IO_RECV_LOCK(so_src, 0);
                KASSERT(error == 0 || error == EWOULDBLOCK,
                    ("%s: failed to lock recv I/O lock: %d", __func__, error));
                if (error == 0)
                        break;
                SOCK_IO_SEND_UNLOCK(so_dst);

                error = SOCK_IO_RECV_LOCK(so_src, SBL_WAIT | SBL_NOINTR);
                KASSERT(error == 0,
                    ("%s: failed to lock recv I/O lock: %d", __func__, error));
                error = SOCK_IO_SEND_LOCK(so_dst, 0);
                KASSERT(error == 0 || error == EWOULDBLOCK,
                    ("%s: failed to lock send I/O lock: %d", __func__, error));
                if (error == 0)
                        break;
                SOCK_IO_RECV_UNLOCK(so_src);
        }
}

static void
splice_unlock_pair(struct socket *so_src, struct socket *so_dst)
{
        SOCK_IO_RECV_UNLOCK(so_src);
        SOCK_IO_SEND_UNLOCK(so_dst);
}

/*
 * Move data from the source to the sink.  Assumes that both of the relevant
 * socket I/O locks are held.
 */
static int
so_splice_xfer_data(struct socket *so_src, struct socket *so_dst, off_t max,
    ssize_t *lenp)
{
        struct uio uio;
        struct mbuf *m;
        struct sockbuf *sb_src, *sb_dst;
        ssize_t len;
        long space;
        int error, flags;

        SOCK_IO_RECV_ASSERT_LOCKED(so_src);
        SOCK_IO_SEND_ASSERT_LOCKED(so_dst);

        error = 0;
        m = NULL;
        memset(&uio, 0, sizeof(uio));

        sb_src = &so_src->so_rcv;
        sb_dst = &so_dst->so_snd;

        space = sbspace(sb_dst);
        if (space < 0)
                space = 0;
        len = MIN(max, MIN(space, sbavail(sb_src)));
        if (len == 0) {
                SOCK_RECVBUF_LOCK(so_src);
                if ((sb_src->sb_state & SBS_CANTRCVMORE) != 0)
                        error = EPIPE;
                SOCK_RECVBUF_UNLOCK(so_src);
        } else {
                flags = MSG_DONTWAIT;
                uio.uio_resid = len;
                if (splice_receive_stream && sb_src->sb_tls_info == NULL) {
                        error = soreceive_stream_locked(so_src, sb_src, NULL,
                            &uio, &m, NULL, flags);
                } else {
                        error = soreceive_generic_locked(so_src, NULL,
                            &uio, &m, NULL, &flags);
                }
                if (error != 0 && m != NULL) {
                        m_freem(m);
                        m = NULL;
                }
        }
        if (m != NULL) {
                len -= uio.uio_resid;
                error = sosend_generic_locked(so_dst, NULL, NULL, m, NULL,
                    MSG_DONTWAIT, curthread);
        } else if (error == 0) {
                len = 0;
                SOCK_SENDBUF_LOCK(so_dst);
                if ((sb_dst->sb_state & SBS_CANTSENDMORE) != 0)
                        error = EPIPE;
                SOCK_SENDBUF_UNLOCK(so_dst);
        }
        if (error == 0)
                *lenp = len;
        return (error);
}

/*
 * Transfer data from the source to the sink.
 */
static void
so_splice_xfer(struct so_splice *sp)
{
        struct socket *so_src, *so_dst;
        off_t max;
        ssize_t len;
        int error;

        mtx_assert(&sp->mtx, MA_OWNED);
        KASSERT(sp->state == SPLICE_QUEUED || sp->state == SPLICE_CLOSING,
            ("so_splice_xfer: invalid state %d", sp->state));
        KASSERT(sp->max != 0, ("so_splice_xfer: max == 0"));

        if (sp->state == SPLICE_CLOSING) {
                /* Userspace asked us to close the splice. */
                goto closing;
        }

        sp->state = SPLICE_RUNNING;
        so_src = sp->src;
        so_dst = sp->dst;
        max = sp->max > 0 ? sp->max - so_src->so_splice_sent : OFF_MAX;
        if (max < 0)
                max = 0;

        /*
         * Lock the sockets in order to block userspace from doing anything
         * sneaky.  If an error occurs or one of the sockets can no longer
         * transfer data, we will automatically unsplice.
         */
        mtx_unlock(&sp->mtx);
        splice_lock_pair(so_src, so_dst);

        error = so_splice_xfer_data(so_src, so_dst, max, &len);

        mtx_lock(&sp->mtx);

        /*
         * Update our stats while still holding the socket locks.  This
         * synchronizes with getsockopt(SO_SPLICE), see the comment there.
         */
        if (error == 0) {
                KASSERT(len >= 0, ("%s: len %zd < 0", __func__, len));
                so_src->so_splice_sent += len;
        }
        splice_unlock_pair(so_src, so_dst);

        switch (sp->state) {
        case SPLICE_CLOSING:
closing:
                sp->state = SPLICE_CLOSED;
                wakeup(sp);
                mtx_unlock(&sp->mtx);
                break;
        case SPLICE_RUNNING:
                if (error != 0 ||
                    (sp->max > 0 && so_src->so_splice_sent >= sp->max)) {
                        sp->state = SPLICE_EXCEPTION;
                        soref(so_src);
                        mtx_unlock(&sp->mtx);
                        (void)so_unsplice(so_src, false);
                        sorele(so_src);
                } else {
                        /*
                         * Locklessly check for additional bytes in the source's
                         * receive buffer and queue more work if possible.  We
                         * may end up queuing needless work, but that's ok, and
                         * if we race with a thread inserting more data into the
                         * buffer and observe sbavail() == 0, the splice mutex
                         * ensures that splice_push() will queue more work for
                         * us.
                         */
                        if (sbavail(&so_src->so_rcv) > 0 &&
                            sbspace(&so_dst->so_snd) > 0) {
                                sp->state = SPLICE_QUEUED;
                                mtx_unlock(&sp->mtx);
                                so_splice_dispatch_async(sp);
                        } else {
                                sp->state = SPLICE_IDLE;
                                mtx_unlock(&sp->mtx);
                        }
                }
                break;
        default:
                __assert_unreachable();
        }
}

static void
socket_init(void *tag)
{

        socket_zone = uma_zcreate("socket", sizeof(struct socket), NULL, NULL,
            NULL, NULL, UMA_ALIGN_PTR, 0);
        maxsockets = uma_zone_set_max(socket_zone, maxsockets);
        uma_zone_set_warning(socket_zone, "kern.ipc.maxsockets limit reached");
        EVENTHANDLER_REGISTER(maxsockets_change, socket_zone_change, NULL,
            EVENTHANDLER_PRI_FIRST);
}
SYSINIT(socket, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY, socket_init, NULL);

#ifdef SOCKET_HHOOK
static void
socket_hhook_register(int subtype)
{

        if (hhook_head_register(HHOOK_TYPE_SOCKET, subtype,
            &V_socket_hhh[subtype],
            HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
                printf("%s: WARNING: unable to register hook\n", __func__);
}

static void
socket_hhook_deregister(int subtype)
{

        if (hhook_head_deregister(V_socket_hhh[subtype]) != 0)
                printf("%s: WARNING: unable to deregister hook\n", __func__);
}

static void
socket_vnet_init(const void *unused __unused)
{
        int i;

        /* We expect a contiguous range */
        for (i = 0; i <= HHOOK_SOCKET_LAST; i++)
                socket_hhook_register(i);
}
VNET_SYSINIT(socket_vnet_init, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY,
    socket_vnet_init, NULL);

static void
socket_vnet_uninit(const void *unused __unused)
{
        int i;

        for (i = 0; i <= HHOOK_SOCKET_LAST; i++)
                socket_hhook_deregister(i);
}
VNET_SYSUNINIT(socket_vnet_uninit, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY,
    socket_vnet_uninit, NULL);
#endif  /* SOCKET_HHOOK */

/*
 * Initialise maxsockets.  This SYSINIT must be run after
 * tunable_mbinit().
 */
static void
init_maxsockets(void *ignored)
{

        TUNABLE_INT_FETCH("kern.ipc.maxsockets", &maxsockets);
        maxsockets = imax(maxsockets, maxfiles);
}
SYSINIT(param, SI_SUB_TUNABLES, SI_ORDER_ANY, init_maxsockets, NULL);

/*
 * Sysctl to get and set the maximum global sockets limit.  Notify protocols
 * of the change so that they can update their dependent limits as required.
 */
static int
sysctl_maxsockets(SYSCTL_HANDLER_ARGS)
{
        int error, newmaxsockets;

        newmaxsockets = maxsockets;
        error = sysctl_handle_int(oidp, &newmaxsockets, 0, req);
        if (error == 0 && req->newptr && newmaxsockets != maxsockets) {
                if (newmaxsockets > maxsockets &&
                    newmaxsockets <= maxfiles) {
                        maxsockets = newmaxsockets;
                        EVENTHANDLER_INVOKE(maxsockets_change);
                } else
                        error = EINVAL;
        }
        return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, maxsockets,
    CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
    &maxsockets, 0, sysctl_maxsockets, "IU",
    "Maximum number of sockets available");

/*
 * Socket operation routines.  These routines are called by the routines in
 * sys_socket.c or from a system process, and implement the semantics of
 * socket operations by switching out to the protocol specific routines.
 */

/*
 * Get a socket structure from our zone, and initialize it.  Note that it
 * would probably be better to allocate socket and PCB at the same time, but
 * I'm not convinced that all the protocols can be easily modified to do
 * this.
 *
 * soalloc() returns a socket with a ref count of 0.
 */
static struct socket *
soalloc(struct vnet *vnet)
{
        struct socket *so;

        so = uma_zalloc(socket_zone, M_NOWAIT | M_ZERO);
        if (so == NULL)
                return (NULL);
#ifdef MAC
        if (mac_socket_init(so, M_NOWAIT) != 0) {
                uma_zfree(socket_zone, so);
                return (NULL);
        }
#endif
        if (khelp_init_osd(HELPER_CLASS_SOCKET, &so->osd)) {
                uma_zfree(socket_zone, so);
                return (NULL);
        }

        /*
         * The socket locking protocol allows to lock 2 sockets at a time,
         * however, the first one must be a listening socket.  WITNESS lacks
         * a feature to change class of an existing lock, so we use DUPOK.
         */
        mtx_init(&so->so_lock, "socket", NULL, MTX_DEF | MTX_DUPOK);
        so->so_rcv.sb_sel = &so->so_rdsel;
        so->so_snd.sb_sel = &so->so_wrsel;
        sx_init(&so->so_snd_sx, "so_snd_sx");
        sx_init(&so->so_rcv_sx, "so_rcv_sx");
        TAILQ_INIT(&so->so_snd.sb_aiojobq);
        TAILQ_INIT(&so->so_rcv.sb_aiojobq);
        TASK_INIT(&so->so_snd.sb_aiotask, 0, soaio_snd, so);
        TASK_INIT(&so->so_rcv.sb_aiotask, 0, soaio_rcv, so);
#ifdef VIMAGE
        VNET_ASSERT(vnet != NULL, ("%s:%d vnet is NULL, so=%p",
            __func__, __LINE__, so));
        so->so_vnet = vnet;
#endif
#ifdef SOCKET_HHOOK
        /* We shouldn't need the so_global_mtx */
        if (hhook_run_socket(so, NULL, HHOOK_SOCKET_CREATE)) {
                /* Do we need more comprehensive error returns? */
                uma_zfree(socket_zone, so);
                return (NULL);
        }
#endif
        mtx_lock(&so_global_mtx);
        so->so_gencnt = ++so_gencnt;
        ++numopensockets;
#ifdef VIMAGE
        vnet->vnet_sockcnt++;
#endif
        mtx_unlock(&so_global_mtx);

        return (so);
}

/*
 * Free the storage associated with a socket at the socket layer, tear down
 * locks, labels, etc.  All protocol state is assumed already to have been
 * torn down (and possibly never set up) by the caller.
 */
void
sodealloc(struct socket *so)
{

        KASSERT(so->so_count == 0, ("sodealloc(): so_count %d", so->so_count));
        KASSERT(so->so_pcb == NULL, ("sodealloc(): so_pcb != NULL"));

        mtx_lock(&so_global_mtx);
        so->so_gencnt = ++so_gencnt;
        --numopensockets;       /* Could be below, but faster here. */
#ifdef VIMAGE
        VNET_ASSERT(so->so_vnet != NULL, ("%s:%d so_vnet is NULL, so=%p",
            __func__, __LINE__, so));
        so->so_vnet->vnet_sockcnt--;
#endif
        mtx_unlock(&so_global_mtx);
#ifdef MAC
        mac_socket_destroy(so);
#endif
#ifdef SOCKET_HHOOK
        hhook_run_socket(so, NULL, HHOOK_SOCKET_CLOSE);
#endif

        khelp_destroy_osd(&so->osd);
        if (SOLISTENING(so)) {
                if (so->sol_accept_filter != NULL)
                        accept_filt_setopt(so, NULL);
        } else {
                if (so->so_rcv.sb_hiwat)
                        (void)chgsbsize(so->so_cred->cr_uidinfo,
                            &so->so_rcv.sb_hiwat, 0, RLIM_INFINITY);
                if (so->so_snd.sb_hiwat)
                        (void)chgsbsize(so->so_cred->cr_uidinfo,
                            &so->so_snd.sb_hiwat, 0, RLIM_INFINITY);
                sx_destroy(&so->so_snd_sx);
                sx_destroy(&so->so_rcv_sx);
        }
        crfree(so->so_cred);
        mtx_destroy(&so->so_lock);
        uma_zfree(socket_zone, so);
}

/*
 * Shim to accomodate protocols that already do their own socket buffers
 * management (marked with PR_SOCKBUF) with protocols that yet do not.
 *
 * Attach via socket(2) is different from attach via accept(2).  In case of
 * normal socket(2) syscall it is the pr_attach that calls soreserve(), even
 * for protocols that don't yet do PR_SOCKBUF.  In case of accepted connection
 * it is our shim that calls soreserve() and the hiwat values are taken from
 * the parent socket.  The SCTP's sopeeloff() hands us a non-listening parent
 * socket.
 *
 * This whole shim should go away when all major protocols fully manage their
 * socket buffers.
 */
static int
soattach(struct socket *so, int proto, struct thread *td, struct socket *head)
{
        int error;

        VNET_ASSERT(curvnet == so->so_vnet,
            ("%s: %p != %p", __func__, curvnet,  so->so_vnet));

        if ((so->so_proto->pr_flags & PR_SOCKBUF) == 0) {
                mtx_init(&so->so_snd_mtx, "so_snd", NULL, MTX_DEF);
                mtx_init(&so->so_rcv_mtx, "so_rcv", NULL, MTX_DEF);
                so->so_snd.sb_mtx = &so->so_snd_mtx;
                so->so_rcv.sb_mtx = &so->so_rcv_mtx;
        }
        if (head == NULL || (error = soreserve(so,
            SOLISTENING(head) ? head->sol_sbsnd_hiwat : head->so_snd.sb_hiwat,
            SOLISTENING(head) ? head->sol_sbrcv_hiwat : head->so_rcv.sb_hiwat))
            == 0)
                error = so->so_proto->pr_attach(so, proto, td);
        if (error != 0 && (so->so_proto->pr_flags & PR_SOCKBUF) == 0) {
                mtx_destroy(&so->so_snd_mtx);
                mtx_destroy(&so->so_rcv_mtx);
        }

        return (error);
}

/*
 * socreate returns a socket with a ref count of 1 and a file descriptor
 * reference.  The socket should be closed with soclose().
 */
int
socreate(int dom, struct socket **aso, int type, int proto,
    struct ucred *cred, struct thread *td)
{
        struct protosw *prp;
        struct socket *so;
        int error;

        prp = pffindproto(dom, type, proto);
        if (prp == NULL) {
                /* No support for domain. */
                if (pffinddomain(dom) == NULL)
                        return (EAFNOSUPPORT);
                /* No support for socket type. */
                if (proto == 0 && type != 0)
                        return (EPROTOTYPE);
                return (EPROTONOSUPPORT);
        }

        MPASS(prp->pr_attach);

        if ((prp->pr_flags & PR_CAPATTACH) == 0) {
                if (CAP_TRACING(td))
                        ktrcapfail(CAPFAIL_PROTO, &proto);
                if (IN_CAPABILITY_MODE(td))
                        return (ECAPMODE);
        }

        if (prison_check_af(cred, prp->pr_domain->dom_family) != 0)
                return (EPROTONOSUPPORT);

        so = soalloc(CRED_TO_VNET(cred));
        if (so == NULL)
                return (ENOBUFS);

        so->so_type = type;
        so->so_cred = crhold(cred);
        if ((prp->pr_domain->dom_family == PF_INET) ||
            (prp->pr_domain->dom_family == PF_INET6) ||
            (prp->pr_domain->dom_family == PF_ROUTE))
                so->so_fibnum = td->td_proc->p_fibnum;
        else
                so->so_fibnum = 0;
        so->so_proto = prp;
#ifdef MAC
        mac_socket_create(cred, so);
#endif
        knlist_init(&so->so_rdsel.si_note, so, so_rdknl_lock, so_rdknl_unlock,
            so_rdknl_assert_lock);
        knlist_init(&so->so_wrsel.si_note, so, so_wrknl_lock, so_wrknl_unlock,
            so_wrknl_assert_lock);
        CURVNET_SET(so->so_vnet);
        error = soattach(so, proto, td, NULL);
        CURVNET_RESTORE();
        if (error) {
                sodealloc(so);
                return (error);
        }
        soref(so);
        *aso = so;
        return (0);
}

#ifdef REGRESSION
static int regression_sonewconn_earlytest = 1;
SYSCTL_INT(_regression, OID_AUTO, sonewconn_earlytest, CTLFLAG_RW,
    &regression_sonewconn_earlytest, 0, "Perform early sonewconn limit test");
#endif

static int sooverprio = LOG_DEBUG;
SYSCTL_INT(_kern_ipc, OID_AUTO, sooverprio, CTLFLAG_RW,
    &sooverprio, 0, "Log priority for listen socket overflows: 0..7 or -1 to disable");

static struct timeval overinterval = { 60, 0 };
SYSCTL_TIMEVAL_SEC(_kern_ipc, OID_AUTO, sooverinterval, CTLFLAG_RW,
    &overinterval,
    "Delay in seconds between warnings for listen socket overflows");

/*
 * When an attempt at a new connection is noted on a socket which supports
 * accept(2), the protocol has two options:
 * 1) Call legacy sonewconn() function, which would call protocol attach
 *    method, same as used for socket(2).
 * 2) Call solisten_clone(), do attach that is specific to a cloned connection,
 *    and then call solisten_enqueue().
 *
 * Note: the ref count on the socket is 0 on return.
 */
struct socket *
solisten_clone(struct socket *head)
{
        struct sbuf descrsb;
        struct socket *so;
        int len, overcount;
        u_int qlen;
        const char localprefix[] = "local:";
        char descrbuf[SUNPATHLEN + sizeof(localprefix)];
#if defined(INET6)
        char addrbuf[INET6_ADDRSTRLEN];
#elif defined(INET)
        char addrbuf[INET_ADDRSTRLEN];
#endif
        bool dolog, over;

        SOLISTEN_LOCK(head);
        over = (head->sol_qlen > 3 * head->sol_qlimit / 2);
#ifdef REGRESSION
        if (regression_sonewconn_earlytest && over) {
#else
        if (over) {
#endif
                head->sol_overcount++;
                dolog = (sooverprio >= 0) &&
                        !!ratecheck(&head->sol_lastover, &overinterval);

                /*
                 * If we're going to log, copy the overflow count and queue
                 * length from the listen socket before dropping the lock.
                 * Also, reset the overflow count.
                 */
                if (dolog) {
                        overcount = head->sol_overcount;
                        head->sol_overcount = 0;
                        qlen = head->sol_qlen;
                }
                SOLISTEN_UNLOCK(head);

                if (dolog) {
                        /*
                         * Try to print something descriptive about the
                         * socket for the error message.
                         */
                        sbuf_new(&descrsb, descrbuf, sizeof(descrbuf),
                            SBUF_FIXEDLEN);
                        switch (head->so_proto->pr_domain->dom_family) {
#if defined(INET) || defined(INET6)
#ifdef INET
                        case AF_INET:
#endif
#ifdef INET6
                        case AF_INET6:
                                if (head->so_proto->pr_domain->dom_family ==
                                    AF_INET6 ||
                                    (sotoinpcb(head)->inp_inc.inc_flags &
                                    INC_ISIPV6)) {
                                        ip6_sprintf(addrbuf,
                                            &sotoinpcb(head)->inp_inc.inc6_laddr);
                                        sbuf_printf(&descrsb, "[%s]", addrbuf);
                                } else
#endif
                                {
#ifdef INET
                                        inet_ntoa_r(
                                            sotoinpcb(head)->inp_inc.inc_laddr,
                                            addrbuf);
                                        sbuf_cat(&descrsb, addrbuf);
#endif
                                }
                                sbuf_printf(&descrsb, ":%hu (proto %u)",
                                    ntohs(sotoinpcb(head)->inp_inc.inc_lport),
                                    head->so_proto->pr_protocol);
                                break;
#endif /* INET || INET6 */
                        case AF_UNIX:
                                sbuf_cat(&descrsb, localprefix);
                                if (sotounpcb(head)->unp_addr != NULL)
                                        len =
                                            sotounpcb(head)->unp_addr->sun_len -
                                            offsetof(struct sockaddr_un,
                                            sun_path);
                                else
                                        len = 0;
                                if (len > 0)
                                        sbuf_bcat(&descrsb,
                                            sotounpcb(head)->unp_addr->sun_path,
                                            len);
                                else
                                        sbuf_cat(&descrsb, "(unknown)");
                                break;
                        }

                        /*
                         * If we can't print something more specific, at least
                         * print the domain name.
                         */
                        if (sbuf_finish(&descrsb) != 0 ||
                            sbuf_len(&descrsb) <= 0) {
                                sbuf_clear(&descrsb);
                                sbuf_cat(&descrsb,
                                    head->so_proto->pr_domain->dom_name ?:
                                    "unknown");
                                sbuf_finish(&descrsb);
                        }
                        KASSERT(sbuf_len(&descrsb) > 0,
                            ("%s: sbuf creation failed", __func__));
                        /*
                         * Preserve the historic listen queue overflow log
                         * message, that starts with "sonewconn:".  It has
                         * been known to sysadmins for years and also test
                         * sys/kern/sonewconn_overflow checks for it.
                         */
                        if (head->so_cred == 0) {
                                log(LOG_PRI(sooverprio),
                                    "sonewconn: pcb %p (%s): "
                                    "Listen queue overflow: %i already in "
                                    "queue awaiting acceptance (%d "
                                    "occurrences)\n", head->so_pcb,
                                    sbuf_data(&descrsb),
                                qlen, overcount);
                        } else {
                                log(LOG_PRI(sooverprio),
                                    "sonewconn: pcb %p (%s): "
                                    "Listen queue overflow: "
                                    "%i already in queue awaiting acceptance "
                                    "(%d occurrences), euid %d, rgid %d, jail %s\n",
                                    head->so_pcb, sbuf_data(&descrsb), qlen,
                                    overcount, head->so_cred->cr_uid,
                                    head->so_cred->cr_rgid,
                                    head->so_cred->cr_prison ?
                                        head->so_cred->cr_prison->pr_name :
                                        "not_jailed");
                        }
                        sbuf_delete(&descrsb);

                        overcount = 0;
                }

                return (NULL);
        }
        SOLISTEN_UNLOCK(head);
        VNET_ASSERT(head->so_vnet != NULL, ("%s: so %p vnet is NULL",
            __func__, head));
        so = soalloc(head->so_vnet);
        if (so == NULL) {
                log(LOG_DEBUG, "%s: pcb %p: New socket allocation failure: "
                    "limit reached or out of memory\n",
                    __func__, head->so_pcb);
                return (NULL);
        }
        so->so_listen = head;
        so->so_type = head->so_type;
        /*
         * POSIX is ambiguous on what options an accept(2)ed socket should
         * inherit from the listener.  Words "create a new socket" may be
         * interpreted as not inheriting anything.  Best programming practice
         * for application developers is to not rely on such inheritance.
         * FreeBSD had historically inherited all so_options excluding
         * SO_ACCEPTCONN, which virtually means all SOL_SOCKET level options,
         * including those completely irrelevant to a new born socket.  For
         * compatibility with older versions we will inherit a list of
         * meaningful options.
         * The crucial bit to inherit is SO_ACCEPTFILTER.  We need it present
         * in the child socket for soisconnected() promoting socket from the
         * incomplete queue to complete.  It will be cleared before the child
         * gets available to accept(2).
         */
        so->so_options = head->so_options & (SO_ACCEPTFILTER | SO_KEEPALIVE |
            SO_DONTROUTE | SO_LINGER | SO_OOBINLINE | SO_NOSIGPIPE);
        so->so_linger = head->so_linger;
        so->so_state = head->so_state;
        so->so_fibnum = head->so_fibnum;
        so->so_proto = head->so_proto;
        so->so_cred = crhold(head->so_cred);
#ifdef SOCKET_HHOOK
        if (V_socket_hhh[HHOOK_SOCKET_NEWCONN]->hhh_nhooks > 0) {
                if (hhook_run_socket(so, head, HHOOK_SOCKET_NEWCONN)) {
                        sodealloc(so);
                        log(LOG_DEBUG, "%s: hhook run failed\n", __func__);
                        return (NULL);
                }
        }
#endif
#ifdef MAC
        mac_socket_newconn(head, so);
#endif
        knlist_init(&so->so_rdsel.si_note, so, so_rdknl_lock, so_rdknl_unlock,
            so_rdknl_assert_lock);
        knlist_init(&so->so_wrsel.si_note, so, so_wrknl_lock, so_wrknl_unlock,
            so_wrknl_assert_lock);
        so->so_rcv.sb_lowat = head->sol_sbrcv_lowat;
        so->so_snd.sb_lowat = head->sol_sbsnd_lowat;
        so->so_rcv.sb_timeo = head->sol_sbrcv_timeo;
        so->so_snd.sb_timeo = head->sol_sbsnd_timeo;
        so->so_rcv.sb_flags = head->sol_sbrcv_flags & SB_AUTOSIZE;
        so->so_snd.sb_flags = head->sol_sbsnd_flags &
            (SB_AUTOSIZE | SB_AUTOLOWAT);

        return (so);
}

/* Connstatus may be 0 or SS_ISCONNECTED. */
struct socket *
sonewconn(struct socket *head, int connstatus)
{
        struct socket *so;

        if ((so = solisten_clone(head)) == NULL)
                return (NULL);

        if (soattach(so, 0, NULL, head) != 0) {
                sodealloc(so);
                log(LOG_DEBUG, "%s: pcb %p: pr_attach() failed\n",
                    __func__, head->so_pcb);
                return (NULL);
        }

        (void)solisten_enqueue(so, connstatus);

        return (so);
}

/*
 * Enqueue socket cloned by solisten_clone() to the listen queue of the
 * listener it has been cloned from.
 *
 * Return 'true' if socket landed on complete queue, otherwise 'false'.
 */
bool
solisten_enqueue(struct socket *so, int connstatus)
{
        struct socket *head = so->so_listen;

        MPASS(refcount_load(&so->so_count) == 0);
        refcount_init(&so->so_count, 1);

        SOLISTEN_LOCK(head);
        if (head->sol_accept_filter != NULL)
                connstatus = 0;
        so->so_state |= connstatus;
        soref(head); /* A socket on (in)complete queue refs head. */
        if (connstatus) {
                TAILQ_INSERT_TAIL(&head->sol_comp, so, so_list);
                so->so_qstate = SQ_COMP;
                head->sol_qlen++;
                solisten_wakeup(head);  /* unlocks */
                return (true);
        } else {
                /*
                 * Keep removing sockets from the head until there's room for
                 * us to insert on the tail.  In pre-locking revisions, this
                 * was a simple if(), but as we could be racing with other
                 * threads and soabort() requires dropping locks, we must
                 * loop waiting for the condition to be true.
                 */
                while (head->sol_incqlen > head->sol_qlimit) {
                        struct socket *sp;

                        sp = TAILQ_FIRST(&head->sol_incomp);
                        TAILQ_REMOVE(&head->sol_incomp, sp, so_list);
                        head->sol_incqlen--;
                        SOCK_LOCK(sp);
                        sp->so_qstate = SQ_NONE;
                        sp->so_listen = NULL;
                        SOCK_UNLOCK(sp);
                        sorele_locked(head);    /* does SOLISTEN_UNLOCK, head stays */
                        soabort(sp);
                        SOLISTEN_LOCK(head);
                }
                TAILQ_INSERT_TAIL(&head->sol_incomp, so, so_list);
                so->so_qstate = SQ_INCOMP;
                head->sol_incqlen++;
                SOLISTEN_UNLOCK(head);
                return (false);
        }
}

#if defined(SCTP) || defined(SCTP_SUPPORT)
/*
 * Socket part of sctp_peeloff().  Create a new socket for an
 * association.  The new socket is returned with a reference.
 *
 * XXXGL: reduce copy-paste with solisten_clone().
 */
struct socket *
sopeeloff(struct socket *head, struct protosw *so_proto)
{
        struct socket *so;

        VNET_ASSERT(head->so_vnet != NULL, ("%s:%d so_vnet is NULL, head=%p",
            __func__, __LINE__, head));
        KASSERT(head->so_type == SOCK_SEQPACKET,
            ("%s: unexpecte so_type: %d", __func__, head->so_type));
        so = soalloc(head->so_vnet);
        if (so == NULL) {
                log(LOG_DEBUG, "%s: pcb %p: New socket allocation failure: "
                    "limit reached or out of memory\n",
                    __func__, head->so_pcb);
                return (NULL);
        }
        so->so_type = SOCK_STREAM;
        so->so_options = head->so_options;
        so->so_linger = head->so_linger;
        so->so_state = (head->so_state & SS_NBIO) | SS_ISCONNECTED;
        so->so_fibnum = head->so_fibnum;
        so->so_proto = so_proto;
        so->so_cred = crhold(head->so_cred);
#ifdef MAC
        mac_socket_newconn(head, so);
#endif
        knlist_init(&so->so_rdsel.si_note, so, so_rdknl_lock, so_rdknl_unlock,
            so_rdknl_assert_lock);
        knlist_init(&so->so_wrsel.si_note, so, so_wrknl_lock, so_wrknl_unlock,
            so_wrknl_assert_lock);
        if (soattach(so, 0, NULL, head)) {
                sodealloc(so);
                log(LOG_DEBUG, "%s: pcb %p: pr_attach() failed\n",
                    __func__, head->so_pcb);
                return (NULL);
        }
        so->so_rcv.sb_lowat = head->so_rcv.sb_lowat;
        so->so_snd.sb_lowat = head->so_snd.sb_lowat;
        so->so_rcv.sb_timeo = head->so_rcv.sb_timeo;
        so->so_snd.sb_timeo = head->so_snd.sb_timeo;
        so->so_rcv.sb_flags |= head->so_rcv.sb_flags & SB_AUTOSIZE;
        so->so_snd.sb_flags |= head->so_snd.sb_flags & SB_AUTOSIZE;

        soref(so);

        return (so);
}
#endif  /* SCTP */

int
sobind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_bind(so, nam, td);
        CURVNET_RESTORE();
        return (error);
}

int
sobindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_bindat(fd, so, nam, td);
        CURVNET_RESTORE();
        return (error);
}

/*
 * solisten() transitions a socket from a non-listening state to a listening
 * state, but can also be used to update the listen queue depth on an
 * existing listen socket.  The protocol will call back into the sockets
 * layer using solisten_proto_check() and solisten_proto() to check and set
 * socket-layer listen state.  Call backs are used so that the protocol can
 * acquire both protocol and socket layer locks in whatever order is required
 * by the protocol.
 *
 * Protocol implementors are advised to hold the socket lock across the
 * socket-layer test and set to avoid races at the socket layer.
 */
int
solisten(struct socket *so, int backlog, struct thread *td)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_listen(so, backlog, td);
        CURVNET_RESTORE();
        return (error);
}

/*
 * Prepare for a call to solisten_proto().  Acquire all socket buffer locks in
 * order to interlock with socket I/O.
 */
int
solisten_proto_check(struct socket *so)
{
        SOCK_LOCK_ASSERT(so);

        if ((so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING |
            SS_ISDISCONNECTING)) != 0)
                return (EINVAL);

        /*
         * Sleeping is not permitted here, so simply fail if userspace is
         * attempting to transmit or receive on the socket.  This kind of
         * transient failure is not ideal, but it should occur only if userspace
         * is misusing the socket interfaces.
         */
        if (!sx_try_xlock(&so->so_snd_sx))
                return (EAGAIN);
        if (!sx_try_xlock(&so->so_rcv_sx)) {
                sx_xunlock(&so->so_snd_sx);
                return (EAGAIN);
        }
        mtx_lock(&so->so_snd_mtx);
        mtx_lock(&so->so_rcv_mtx);

        /* Interlock with soo_aio_queue() and KTLS. */
        if (!SOLISTENING(so)) {
                bool ktls;

#ifdef KERN_TLS
                ktls = so->so_snd.sb_tls_info != NULL ||
                    so->so_rcv.sb_tls_info != NULL;
#else
                ktls = false;
#endif
                if (ktls ||
                    (so->so_snd.sb_flags & (SB_AIO | SB_AIO_RUNNING)) != 0 ||
                    (so->so_rcv.sb_flags & (SB_AIO | SB_AIO_RUNNING)) != 0) {
                        solisten_proto_abort(so);
                        return (EINVAL);
                }
        }

        return (0);
}

/*
 * Undo the setup done by solisten_proto_check().
 */
void
solisten_proto_abort(struct socket *so)
{
        mtx_unlock(&so->so_snd_mtx);
        mtx_unlock(&so->so_rcv_mtx);
        sx_xunlock(&so->so_snd_sx);
        sx_xunlock(&so->so_rcv_sx);
}

void
solisten_proto(struct socket *so, int backlog)
{
        int sbrcv_lowat, sbsnd_lowat;
        u_int sbrcv_hiwat, sbsnd_hiwat;
        short sbrcv_flags, sbsnd_flags;
        sbintime_t sbrcv_timeo, sbsnd_timeo;

        SOCK_LOCK_ASSERT(so);
        KASSERT((so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING |
            SS_ISDISCONNECTING)) == 0,
            ("%s: bad socket state %p", __func__, so));

        if (SOLISTENING(so))
                goto listening;

        /*
         * Change this socket to listening state.
         */
        sbrcv_lowat = so->so_rcv.sb_lowat;
        sbsnd_lowat = so->so_snd.sb_lowat;
        sbrcv_hiwat = so->so_rcv.sb_hiwat;
        sbsnd_hiwat = so->so_snd.sb_hiwat;
        sbrcv_flags = so->so_rcv.sb_flags;
        sbsnd_flags = so->so_snd.sb_flags;
        sbrcv_timeo = so->so_rcv.sb_timeo;
        sbsnd_timeo = so->so_snd.sb_timeo;

#ifdef MAC
        mac_socketpeer_label_free(so->so_peerlabel);
#endif

        if (!(so->so_proto->pr_flags & PR_SOCKBUF)) {
                sbdestroy(so, SO_SND);
                sbdestroy(so, SO_RCV);
        }

#ifdef INVARIANTS
        bzero(&so->so_rcv,
            sizeof(struct socket) - offsetof(struct socket, so_rcv));
#endif

        so->sol_sbrcv_lowat = sbrcv_lowat;
        so->sol_sbsnd_lowat = sbsnd_lowat;
        so->sol_sbrcv_hiwat = sbrcv_hiwat;
        so->sol_sbsnd_hiwat = sbsnd_hiwat;
        so->sol_sbrcv_flags = sbrcv_flags;
        so->sol_sbsnd_flags = sbsnd_flags;
        so->sol_sbrcv_timeo = sbrcv_timeo;
        so->sol_sbsnd_timeo = sbsnd_timeo;

        so->sol_qlen = so->sol_incqlen = 0;
        TAILQ_INIT(&so->sol_incomp);
        TAILQ_INIT(&so->sol_comp);

        so->sol_accept_filter = NULL;
        so->sol_accept_filter_arg = NULL;
        so->sol_accept_filter_str = NULL;

        so->sol_upcall = NULL;
        so->sol_upcallarg = NULL;

        so->so_options |= SO_ACCEPTCONN;

listening:
        if (backlog < 0 || backlog > V_somaxconn)
                backlog = V_somaxconn;
        so->sol_qlimit = backlog;

        mtx_unlock(&so->so_snd_mtx);
        mtx_unlock(&so->so_rcv_mtx);
        sx_xunlock(&so->so_snd_sx);
        sx_xunlock(&so->so_rcv_sx);
}

/*
 * Wakeup listeners/subsystems once we have a complete connection.
 * Enters with lock, returns unlocked.
 */
void
solisten_wakeup(struct socket *sol)
{

        if (sol->sol_upcall != NULL)
                (void )sol->sol_upcall(sol, sol->sol_upcallarg, M_NOWAIT);
        else {
                selwakeuppri(&sol->so_rdsel, PSOCK);
                KNOTE_LOCKED(&sol->so_rdsel.si_note, 0);
        }
        SOLISTEN_UNLOCK(sol);
        wakeup_one(&sol->sol_comp);
        if ((sol->so_state & SS_ASYNC) && sol->so_sigio != NULL)
                pgsigio(&sol->so_sigio, SIGIO, 0);
}

/*
 * Return single connection off a listening socket queue.  Main consumer of
 * the function is kern_accept4().  Some modules, that do their own accept
 * management also use the function.  The socket reference held by the
 * listen queue is handed to the caller.
 *
 * Listening socket must be locked on entry and is returned unlocked on
 * return.
 * The flags argument is set of accept4(2) flags and ACCEPT4_INHERIT.
 */
int
solisten_dequeue(struct socket *head, struct socket **ret, int flags)
{
        struct socket *so;
        int error;

        SOLISTEN_LOCK_ASSERT(head);

        while (!(head->so_state & SS_NBIO) && TAILQ_EMPTY(&head->sol_comp) &&
            head->so_error == 0) {
                error = msleep(&head->sol_comp, SOCK_MTX(head), PSOCK | PCATCH,
                    "accept", 0);
                if (error != 0) {
                        SOLISTEN_UNLOCK(head);
                        return (error);
                }
        }
        if (head->so_error) {
                error = head->so_error;
                head->so_error = 0;
        } else if ((head->so_state & SS_NBIO) && TAILQ_EMPTY(&head->sol_comp))
                error = EWOULDBLOCK;
        else
                error = 0;
        if (error) {
                SOLISTEN_UNLOCK(head);
                return (error);
        }
        so = TAILQ_FIRST(&head->sol_comp);
        SOCK_LOCK(so);
        KASSERT(so->so_qstate == SQ_COMP,
            ("%s: so %p not SQ_COMP", __func__, so));
        head->sol_qlen--;
        so->so_qstate = SQ_NONE;
        so->so_listen = NULL;
        TAILQ_REMOVE(&head->sol_comp, so, so_list);
        if (flags & ACCEPT4_INHERIT)
                so->so_state |= (head->so_state & SS_NBIO);
        else
                so->so_state |= (flags & SOCK_NONBLOCK) ? SS_NBIO : 0;
        SOCK_UNLOCK(so);
        sorele_locked(head);

        *ret = so;
        return (0);
}

static struct so_splice *
so_splice_alloc(off_t max)
{
        struct so_splice *sp;

        sp = uma_zalloc(splice_zone, M_WAITOK);
        sp->src = NULL;
        sp->dst = NULL;
        sp->max = max > 0 ? max : -1;
        sp->wq_index = atomic_fetchadd_32(&splice_index, 1) % splice_num_wq;
        sp->state = SPLICE_INIT;
        TIMEOUT_TASK_INIT(taskqueue_thread, &sp->timeout, 0, so_splice_timeout,
            sp);
        return (sp);
}

static void
so_splice_free(struct so_splice *sp)
{
        KASSERT(sp->state == SPLICE_CLOSED,
            ("so_splice_free: sp %p not closed", sp));
        uma_zfree(splice_zone, sp);
}

static void
so_splice_timeout(void *arg, int pending __unused)
{
        struct so_splice *sp;

        sp = arg;
        (void)so_unsplice(sp->src, true);
}

/*
 * Splice the output from so to the input of so2.
 */
static int
so_splice(struct socket *so, struct socket *so2, struct splice *splice)
{
        struct so_splice *sp;
        int error;

        if (splice->sp_max < 0)
                return (EINVAL);
        /* Handle only TCP for now; TODO: other streaming protos */
        if (so->so_proto->pr_protocol != IPPROTO_TCP ||
            so2->so_proto->pr_protocol != IPPROTO_TCP)
                return (EPROTONOSUPPORT);
        if (so->so_vnet != so2->so_vnet)
                return (EINVAL);

        /* so_splice_xfer() assumes that we're using these implementations. */
        KASSERT(so->so_proto->pr_sosend == sosend_generic,
            ("so_splice: sosend not sosend_generic"));
        KASSERT(so2->so_proto->pr_soreceive == soreceive_generic ||
            so2->so_proto->pr_soreceive == soreceive_stream,
            ("so_splice: soreceive not soreceive_generic/stream"));

        sp = so_splice_alloc(splice->sp_max);
        so->so_splice_sent = 0;
        sp->src = so;
        sp->dst = so2;

        error = 0;
        SOCK_LOCK(so);
        if (SOLISTENING(so))
                error = EINVAL;
        else if ((so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING)) == 0)
                error = ENOTCONN;
        else if (so->so_splice != NULL)
                error = EBUSY;
        if (error != 0) {
                SOCK_UNLOCK(so);
                uma_zfree(splice_zone, sp);
                return (error);
        }
        SOCK_RECVBUF_LOCK(so);
        if (so->so_rcv.sb_tls_info != NULL) {
                SOCK_RECVBUF_UNLOCK(so);
                SOCK_UNLOCK(so);
                uma_zfree(splice_zone, sp);
                return (EINVAL);
        }
        so->so_rcv.sb_flags |= SB_SPLICED;
        so->so_splice = sp;
        soref(so);
        SOCK_RECVBUF_UNLOCK(so);
        SOCK_UNLOCK(so);

        error = 0;
        SOCK_LOCK(so2);
        if (SOLISTENING(so2))
                error = EINVAL;
        else if ((so2->so_state & (SS_ISCONNECTED | SS_ISCONNECTING)) == 0)
                error = ENOTCONN;
        else if (so2->so_splice_back != NULL)
                error = EBUSY;
        if (error != 0) {
                SOCK_UNLOCK(so2);
                mtx_lock(&sp->mtx);
                sp->dst = NULL;
                sp->state = SPLICE_EXCEPTION;
                mtx_unlock(&sp->mtx);
                so_unsplice(so, false);
                return (error);
        }
        SOCK_SENDBUF_LOCK(so2);
        if (so->so_snd.sb_tls_info != NULL) {
                SOCK_SENDBUF_UNLOCK(so2);
                SOCK_UNLOCK(so2);
                mtx_lock(&sp->mtx);
                sp->dst = NULL;
                sp->state = SPLICE_EXCEPTION;
                mtx_unlock(&sp->mtx);
                so_unsplice(so, false);
                return (EINVAL);
        }
        so2->so_snd.sb_flags |= SB_SPLICED;
        so2->so_splice_back = sp;
        soref(so2);
        mtx_lock(&sp->mtx);
        SOCK_SENDBUF_UNLOCK(so2);
        SOCK_UNLOCK(so2);

        if (splice->sp_idle.tv_sec != 0 || splice->sp_idle.tv_usec != 0) {
                taskqueue_enqueue_timeout_sbt(taskqueue_thread, &sp->timeout,
                    tvtosbt(splice->sp_idle), 0, C_PREL(4));
        }

        /*
         * Transfer any data already present in the socket buffer.
         */
        KASSERT(sp->state == SPLICE_INIT,
            ("so_splice: splice %p state %d", sp, sp->state));
        sp->state = SPLICE_QUEUED;
        so_splice_xfer(sp);
        return (0);
}

static int
so_unsplice(struct socket *so, bool timeout)
{
        struct socket *so2;
        struct so_splice *sp;
        bool drain, so2rele;

        /*
         * First unset SB_SPLICED and hide the splice structure so that
         * wakeup routines will stop enqueuing work.  This also ensures that
         * a only a single thread will proceed with the unsplice.
         */
        SOCK_LOCK(so);
        if (SOLISTENING(so)) {
                SOCK_UNLOCK(so);
                return (EINVAL);
        }
        SOCK_RECVBUF_LOCK(so);
        if ((so->so_rcv.sb_flags & SB_SPLICED) == 0) {
                SOCK_RECVBUF_UNLOCK(so);
                SOCK_UNLOCK(so);
                return (ENOTCONN);
        }
        sp = so->so_splice;
        mtx_lock(&sp->mtx);
        if (sp->state == SPLICE_INIT) {
                /*
                 * A splice is in the middle of being set up.
                 */
                mtx_unlock(&sp->mtx);
                SOCK_RECVBUF_UNLOCK(so);
                SOCK_UNLOCK(so);
                return (ENOTCONN);
        }
        mtx_unlock(&sp->mtx);
        so->so_rcv.sb_flags &= ~SB_SPLICED;
        so->so_splice = NULL;
        SOCK_RECVBUF_UNLOCK(so);
        SOCK_UNLOCK(so);

        so2 = sp->dst;
        if (so2 != NULL) {
                SOCK_LOCK(so2);
                KASSERT(!SOLISTENING(so2), ("%s: so2 is listening", __func__));
                SOCK_SENDBUF_LOCK(so2);
                KASSERT((so2->so_snd.sb_flags & SB_SPLICED) != 0,
                    ("%s: so2 is not spliced", __func__));
                KASSERT(so2->so_splice_back == sp,
                    ("%s: so_splice_back != sp", __func__));
                so2->so_snd.sb_flags &= ~SB_SPLICED;
                so2rele = so2->so_splice_back != NULL;
                so2->so_splice_back = NULL;
                SOCK_SENDBUF_UNLOCK(so2);
                SOCK_UNLOCK(so2);
        }

        /*
         * No new work is being enqueued.  The worker thread might be
         * splicing data right now, in which case we want to wait for it to
         * finish before proceeding.
         */
        mtx_lock(&sp->mtx);
        switch (sp->state) {
        case SPLICE_QUEUED:
        case SPLICE_RUNNING:
                sp->state = SPLICE_CLOSING;
                while (sp->state == SPLICE_CLOSING)
                        msleep(sp, &sp->mtx, PSOCK, "unsplice", 0);
                break;
        case SPLICE_INIT:
        case SPLICE_IDLE:
        case SPLICE_EXCEPTION:
                sp->state = SPLICE_CLOSED;
                break;
        default:
                __assert_unreachable();
        }
        if (!timeout) {
                drain = taskqueue_cancel_timeout(taskqueue_thread, &sp->timeout,
                    NULL) != 0;
        } else {
                drain = false;
        }
        mtx_unlock(&sp->mtx);
        if (drain)
                taskqueue_drain_timeout(taskqueue_thread, &sp->timeout);

        /*
         * Now we hold the sole reference to the splice structure.
         * Clean up: signal userspace and release socket references.
         */
        sorwakeup(so);
        CURVNET_SET(so->so_vnet);
        sorele(so);
        if (so2 != NULL) {
                sowwakeup(so2);
                if (so2rele)
                        sorele(so2);
        }
        CURVNET_RESTORE();
        so_splice_free(sp);
        return (0);
}

/*
 * Free socket upon release of the very last reference.
 */
static void
sofree(struct socket *so)
{
        struct protosw *pr = so->so_proto;

        SOCK_LOCK_ASSERT(so);
        KASSERT(refcount_load(&so->so_count) == 0,
            ("%s: so %p has references", __func__, so));
        KASSERT(SOLISTENING(so) || so->so_qstate == SQ_NONE,
            ("%s: so %p is on listen queue", __func__, so));
        KASSERT(SOLISTENING(so) || (so->so_rcv.sb_flags & SB_SPLICED) == 0,
            ("%s: so %p rcvbuf is spliced", __func__, so));
        KASSERT(SOLISTENING(so) || (so->so_snd.sb_flags & SB_SPLICED) == 0,
            ("%s: so %p sndbuf is spliced", __func__, so));
        KASSERT(so->so_splice == NULL && so->so_splice_back == NULL,
            ("%s: so %p has spliced data", __func__, so));

        SOCK_UNLOCK(so);

        if (so->so_dtor != NULL)
                so->so_dtor(so);

        VNET_SO_ASSERT(so);
        if (pr->pr_detach != NULL)
                pr->pr_detach(so);

        if (!(pr->pr_flags & PR_SOCKBUF) && !SOLISTENING(so)) {
                /*
                 * From this point on, we assume that no other references to
                 * this socket exist anywhere else in the stack.  Therefore,
                 * no locks need to be acquired or held.
                 */
#ifdef INVARIANTS
                SOCK_SENDBUF_LOCK(so);
                SOCK_RECVBUF_LOCK(so);
#endif
                sbdestroy(so, SO_SND);
                sbdestroy(so, SO_RCV);
#ifdef INVARIANTS
                SOCK_SENDBUF_UNLOCK(so);
                SOCK_RECVBUF_UNLOCK(so);
#endif
                mtx_destroy(&so->so_snd_mtx);
                mtx_destroy(&so->so_rcv_mtx);
        }
        seldrain(&so->so_rdsel);
        seldrain(&so->so_wrsel);
        knlist_destroy(&so->so_rdsel.si_note);
        knlist_destroy(&so->so_wrsel.si_note);
        sodealloc(so);
}

/*
 * Release a reference on a socket while holding the socket lock.
 * Unlocks the socket lock before returning.
 */
void
sorele_locked(struct socket *so)
{
        SOCK_LOCK_ASSERT(so);
        if (refcount_release(&so->so_count))
                sofree(so);
        else
                SOCK_UNLOCK(so);
}

/*
 * Close a socket on last file table reference removal.  Initiate disconnect
 * if connected.  Free socket when disconnect complete.
 *
 * This function will sorele() the socket.  Note that soclose() may be called
 * prior to the ref count reaching zero.  The actual socket structure will
 * not be freed until the ref count reaches zero.
 */
int
soclose(struct socket *so)
{
        struct accept_queue lqueue;
        int error = 0;
        bool listening, last __diagused;

        CURVNET_SET(so->so_vnet);
        funsetown(&so->so_sigio);
        if (so->so_state & SS_ISCONNECTED) {
                if ((so->so_state & SS_ISDISCONNECTING) == 0) {
                        error = sodisconnect(so);
                        if (error) {
                                if (error == ENOTCONN)
                                        error = 0;
                                goto drop;
                        }
                }

                if ((so->so_options & SO_LINGER) != 0 && so->so_linger != 0) {
                        if ((so->so_state & SS_ISDISCONNECTING) &&
                            (so->so_state & SS_NBIO))
                                goto drop;
                        while (so->so_state & SS_ISCONNECTED) {
                                error = tsleep(&so->so_timeo,
                                    PSOCK | PCATCH, "soclos",
                                    so->so_linger * hz);
                                if (error)
                                        break;
                        }
                }
        }

drop:
        if (so->so_proto->pr_close != NULL)
                so->so_proto->pr_close(so);

        SOCK_LOCK(so);
        if ((listening = SOLISTENING(so))) {
                struct socket *sp;

                TAILQ_INIT(&lqueue);
                TAILQ_SWAP(&lqueue, &so->sol_incomp, socket, so_list);
                TAILQ_CONCAT(&lqueue, &so->sol_comp, so_list);

                so->sol_qlen = so->sol_incqlen = 0;

                TAILQ_FOREACH(sp, &lqueue, so_list) {
                        SOCK_LOCK(sp);
                        sp->so_qstate = SQ_NONE;
                        sp->so_listen = NULL;
                        SOCK_UNLOCK(sp);
                        last = refcount_release(&so->so_count);
                        KASSERT(!last, ("%s: released last reference for %p",
                            __func__, so));
                }
        }
        sorele_locked(so);
        if (listening) {
                struct socket *sp, *tsp;

                TAILQ_FOREACH_SAFE(sp, &lqueue, so_list, tsp)
                        soabort(sp);
        }
        CURVNET_RESTORE();
        return (error);
}

/*
 * soabort() is used to abruptly tear down a connection, such as when a
 * resource limit is reached (listen queue depth exceeded), or if a listen
 * socket is closed while there are sockets waiting to be accepted.
 *
 * This interface is tricky, because it is called on an unreferenced socket,
 * and must be called only by a thread that has actually removed the socket
 * from the listen queue it was on.  Likely this thread holds the last
 * reference on the socket and soabort() will proceed with sofree().  But
 * it might be not the last, as the sockets on the listen queues are seen
 * from the protocol side.
 *
 * This interface will call into the protocol code, so must not be called
 * with any socket locks held.  Protocols do call it while holding their own
 * recursible protocol mutexes, but this is something that should be subject
 * to review in the future.
 *
 * Usually socket should have a single reference left, but this is not a
 * requirement.  In the past, when we have had named references for file
 * descriptor and protocol, we asserted that none of them are being held.
 */
void
soabort(struct socket *so)
{

        VNET_SO_ASSERT(so);

        if (so->so_proto->pr_abort != NULL)
                so->so_proto->pr_abort(so);
        SOCK_LOCK(so);
        sorele_locked(so);
}

int
soaccept(struct socket *so, struct sockaddr *sa)
{
#ifdef INVARIANTS
        u_char len = sa->sa_len;
#endif
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_accept(so, sa);
        KASSERT(sa->sa_len <= len,
            ("%s: protocol %p sockaddr overflow", __func__, so->so_proto));
        CURVNET_RESTORE();
        return (error);
}

int
sopeeraddr(struct socket *so, struct sockaddr *sa)
{
#ifdef INVARIANTS
        u_char len = sa->sa_len;
#endif
        int error;

        CURVNET_ASSERT_SET();

        error = so->so_proto->pr_peeraddr(so, sa);
        KASSERT(sa->sa_len <= len,
            ("%s: protocol %p sockaddr overflow", __func__, so->so_proto));

        return (error);
}

int
sosockaddr(struct socket *so, struct sockaddr *sa)
{
#ifdef INVARIANTS
        u_char len = sa->sa_len;
#endif
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_sockaddr(so, sa);
        KASSERT(sa->sa_len <= len,
            ("%s: protocol %p sockaddr overflow", __func__, so->so_proto));
        CURVNET_RESTORE();

        return (error);
}

int
soconnect(struct socket *so, struct sockaddr *nam, struct thread *td)
{

        return (soconnectat(AT_FDCWD, so, nam, td));
}

int
soconnectat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
{
        int error;

        CURVNET_SET(so->so_vnet);

        /*
         * If protocol is connection-based, can only connect once.
         * Otherwise, if connected, try to disconnect first.  This allows
         * user to disconnect by connecting to, e.g., a null address.
         *
         * Note, this check is racy and may need to be re-evaluated at the
         * protocol layer.
         */
        if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
            ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
            (error = sodisconnect(so)))) {
                error = EISCONN;
        } else {
                /*
                 * Prevent accumulated error from previous connection from
                 * biting us.
                 */
                so->so_error = 0;
                if (fd == AT_FDCWD) {
                        error = so->so_proto->pr_connect(so, nam, td);
                } else {
                        error = so->so_proto->pr_connectat(fd, so, nam, td);
                }
        }
        CURVNET_RESTORE();

        return (error);
}

int
soconnect2(struct socket *so1, struct socket *so2)
{
        int error;

        CURVNET_SET(so1->so_vnet);
        error = so1->so_proto->pr_connect2(so1, so2);
        CURVNET_RESTORE();
        return (error);
}

int
sodisconnect(struct socket *so)
{
        int error;

        if ((so->so_state & SS_ISCONNECTED) == 0)
                return (ENOTCONN);
        if (so->so_state & SS_ISDISCONNECTING)
                return (EALREADY);
        VNET_SO_ASSERT(so);
        error = so->so_proto->pr_disconnect(so);
        return (error);
}

int
sosend_dgram(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
{
        long space;
        ssize_t resid;
        int clen = 0, error, dontroute;

        KASSERT(so->so_type == SOCK_DGRAM, ("sosend_dgram: !SOCK_DGRAM"));
        KASSERT(so->so_proto->pr_flags & PR_ATOMIC,
            ("sosend_dgram: !PR_ATOMIC"));

        if (uio != NULL)
                resid = uio->uio_resid;
        else
                resid = top->m_pkthdr.len;
        /*
         * In theory resid should be unsigned.  However, space must be
         * signed, as it might be less than 0 if we over-committed, and we
         * must use a signed comparison of space and resid.  On the other
         * hand, a negative resid causes us to loop sending 0-length
         * segments to the protocol.
         */
        if (resid < 0) {
                error = EINVAL;
                goto out;
        }

        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0;
        if (td != NULL)
                td->td_ru.ru_msgsnd++;
        if (control != NULL)
                clen = control->m_len;

        SOCKBUF_LOCK(&so->so_snd);
        if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
                SOCKBUF_UNLOCK(&so->so_snd);
                error = EPIPE;
                goto out;
        }
        if (so->so_error) {
                error = so->so_error;
                so->so_error = 0;
                SOCKBUF_UNLOCK(&so->so_snd);
                goto out;
        }
        if ((so->so_state & SS_ISCONNECTED) == 0) {
                /*
                 * `sendto' and `sendmsg' is allowed on a connection-based
                 * socket if it supports implied connect.  Return ENOTCONN if
                 * not connected and no address is supplied.
                 */
                if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
                    (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
                        if (!(resid == 0 && clen != 0)) {
                                SOCKBUF_UNLOCK(&so->so_snd);
                                error = ENOTCONN;
                                goto out;
                        }
                } else if (addr == NULL) {
                        if (so->so_proto->pr_flags & PR_CONNREQUIRED)
                                error = ENOTCONN;
                        else
                                error = EDESTADDRREQ;
                        SOCKBUF_UNLOCK(&so->so_snd);
                        goto out;
                }
        }

        /*
         * Do we need MSG_OOB support in SOCK_DGRAM?  Signs here may be a
         * problem and need fixing.
         */
        space = sbspace(&so->so_snd);
        if (flags & MSG_OOB)
                space += 1024;
        space -= clen;
        SOCKBUF_UNLOCK(&so->so_snd);
        if (resid > space) {
                error = EMSGSIZE;
                goto out;
        }
        if (uio == NULL) {
                resid = 0;
                if (flags & MSG_EOR)
                        top->m_flags |= M_EOR;
        } else {
                /*
                 * Copy the data from userland into a mbuf chain.
                 * If no data is to be copied in, a single empty mbuf
                 * is returned.
                 */
                top = m_uiotombuf(uio, M_WAITOK, space, max_hdr,
                    (M_PKTHDR | ((flags & MSG_EOR) ? M_EOR : 0)));
                if (top == NULL) {
                        error = EFAULT; /* only possible error */
                        goto out;
                }
                space -= resid - uio->uio_resid;
                resid = uio->uio_resid;
        }
        KASSERT(resid == 0, ("sosend_dgram: resid != 0"));
        /*
         * XXXRW: Frobbing SO_DONTROUTE here is even worse without sblock
         * than with.
         */
        if (dontroute) {
                SOCK_LOCK(so);
                so->so_options |= SO_DONTROUTE;
                SOCK_UNLOCK(so);
        }
        /*
         * XXX all the SBS_CANTSENDMORE checks previously done could be out
         * of date.  We could have received a reset packet in an interrupt or
         * maybe we slept while doing page faults in uiomove() etc.  We could
         * probably recheck again inside the locking protection here, but
         * there are probably other places that this also happens.  We must
         * rethink this.
         */
        VNET_SO_ASSERT(so);
        error = so->so_proto->pr_send(so, (flags & MSG_OOB) ? PRUS_OOB :
        /*
         * If the user set MSG_EOF, the protocol understands this flag and
         * nothing left to send then use PRU_SEND_EOF instead of PRU_SEND.
         */
            ((flags & MSG_EOF) &&
             (so->so_proto->pr_flags & PR_IMPLOPCL) &&
             (resid <= 0)) ?
                PRUS_EOF :
                /* If there is more to send set PRUS_MORETOCOME */
                (flags & MSG_MORETOCOME) ||
                (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
                top, addr, control, td);
        if (dontroute) {
                SOCK_LOCK(so);
                so->so_options &= ~SO_DONTROUTE;
                SOCK_UNLOCK(so);
        }
        clen = 0;
        control = NULL;
        top = NULL;
out:
        if (top != NULL)
                m_freem(top);
        if (control != NULL)
                m_freem(control);
        return (error);
}

/*
 * Send on a socket.  If send must go all at once and message is larger than
 * send buffering, then hard error.  Lock against other senders.  If must go
 * all at once and not enough room now, then inform user that this would
 * block and do nothing.  Otherwise, if nonblocking, send as much as
 * possible.  The data to be sent is described by "uio" if nonzero, otherwise
 * by the mbuf chain "top" (which must be null if uio is not).  Data provided
 * in mbuf chain must be small enough to send all at once.
 *
 * Returns nonzero on error, timeout or signal; callers must check for short
 * counts if EINTR/ERESTART are returned.  Data and control buffers are freed
 * on return.
 */
static int
sosend_generic_locked(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
{
        long space;
        ssize_t resid;
        int clen = 0, error, dontroute;
        int atomic = sosendallatonce(so) || top;
        int pr_send_flag;
#ifdef KERN_TLS
        struct ktls_session *tls;
        int tls_enq_cnt, tls_send_flag;
        uint8_t tls_rtype;

        tls = NULL;
        tls_rtype = TLS_RLTYPE_APP;
#endif

        SOCK_IO_SEND_ASSERT_LOCKED(so);

        if (uio != NULL)
                resid = uio->uio_resid;
        else if ((top->m_flags & M_PKTHDR) != 0)
                resid = top->m_pkthdr.len;
        else
                resid = m_length(top, NULL);
        /*
         * In theory resid should be unsigned.  However, space must be
         * signed, as it might be less than 0 if we over-committed, and we
         * must use a signed comparison of space and resid.  On the other
         * hand, a negative resid causes us to loop sending 0-length
         * segments to the protocol.
         *
         * Also check to make sure that MSG_EOR isn't used on SOCK_STREAM
         * type sockets since that's an error.
         */
        if (resid < 0 || (so->so_type == SOCK_STREAM && (flags & MSG_EOR))) {
                error = EINVAL;
                goto out;
        }

        dontroute =
            (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
            (so->so_proto->pr_flags & PR_ATOMIC);
        if (td != NULL)
                td->td_ru.ru_msgsnd++;
        if (control != NULL)
                clen = control->m_len;

#ifdef KERN_TLS
        tls_send_flag = 0;
        tls = ktls_hold(so->so_snd.sb_tls_info);
        if (tls != NULL) {
                if (tls->mode == TCP_TLS_MODE_SW)
                        tls_send_flag = PRUS_NOTREADY;

                if (control != NULL) {
                        struct cmsghdr *cm = mtod(control, struct cmsghdr *);

                        if (clen >= sizeof(*cm) &&
                            cm->cmsg_type == TLS_SET_RECORD_TYPE) {
                                tls_rtype = *((uint8_t *)CMSG_DATA(cm));
                                clen = 0;
                                m_freem(control);
                                control = NULL;
                                atomic = 1;
                        }
                }

                if (resid == 0 && !ktls_permit_empty_frames(tls)) {
                        error = EINVAL;
                        goto out;
                }
        }
#endif

restart:
        do {
                SOCKBUF_LOCK(&so->so_snd);
                if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
                        SOCKBUF_UNLOCK(&so->so_snd);
                        error = EPIPE;
                        goto out;
                }
                if (so->so_error) {
                        error = so->so_error;
                        so->so_error = 0;
                        SOCKBUF_UNLOCK(&so->so_snd);
                        goto out;
                }
                if ((so->so_state & SS_ISCONNECTED) == 0) {
                        /*
                         * `sendto' and `sendmsg' is allowed on a connection-
                         * based socket if it supports implied connect.
                         * Return ENOTCONN if not connected and no address is
                         * supplied.
                         */
                        if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
                            (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
                                if (!(resid == 0 && clen != 0)) {
                                        SOCKBUF_UNLOCK(&so->so_snd);
                                        error = ENOTCONN;
                                        goto out;
                                }
                        } else if (addr == NULL) {
                                SOCKBUF_UNLOCK(&so->so_snd);
                                if (so->so_proto->pr_flags & PR_CONNREQUIRED)
                                        error = ENOTCONN;
                                else
                                        error = EDESTADDRREQ;
                                goto out;
                        }
                }
                space = sbspace(&so->so_snd);
                if (flags & MSG_OOB)
                        space += 1024;
                if ((atomic && resid > so->so_snd.sb_hiwat) ||
                    clen > so->so_snd.sb_hiwat) {
                        SOCKBUF_UNLOCK(&so->so_snd);
                        error = EMSGSIZE;
                        goto out;
                }
                if (space < resid + clen &&
                    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
                        if ((so->so_state & SS_NBIO) ||
                            (flags & (MSG_NBIO | MSG_DONTWAIT)) != 0) {
                                SOCKBUF_UNLOCK(&so->so_snd);
                                error = EWOULDBLOCK;
                                goto out;
                        }
                        error = sbwait(so, SO_SND);
                        SOCKBUF_UNLOCK(&so->so_snd);
                        if (error)
                                goto out;
                        goto restart;
                }
                SOCKBUF_UNLOCK(&so->so_snd);
                space -= clen;
                do {
                        if (uio == NULL) {
                                resid = 0;
                                if (flags & MSG_EOR)
                                        top->m_flags |= M_EOR;
#ifdef KERN_TLS
                                if (tls != NULL) {
                                        ktls_frame(top, tls, &tls_enq_cnt,
                                            tls_rtype);
                                        tls_rtype = TLS_RLTYPE_APP;
                                }
#endif
                        } else {
                                /*
                                 * Copy the data from userland into a mbuf
                                 * chain.  If resid is 0, which can happen
                                 * only if we have control to send, then
                                 * a single empty mbuf is returned.  This
                                 * is a workaround to prevent protocol send
                                 * methods to panic.
                                 */
#ifdef KERN_TLS
                                if (tls != NULL) {
                                        top = m_uiotombuf(uio, M_WAITOK, space,
                                            tls->params.max_frame_len,
                                            M_EXTPG |
                                            ((flags & MSG_EOR) ? M_EOR : 0));
                                        if (top != NULL) {
                                                ktls_frame(top, tls,
                                                    &tls_enq_cnt, tls_rtype);
                                        }
                                        tls_rtype = TLS_RLTYPE_APP;
                                } else
#endif
                                        top = m_uiotombuf(uio, M_WAITOK, space,
                                            (atomic ? max_hdr : 0),
                                            (atomic ? M_PKTHDR : 0) |
                                            ((flags & MSG_EOR) ? M_EOR : 0));
                                if (top == NULL) {
                                        error = EFAULT; /* only possible error */
                                        goto out;
                                }
                                space -= resid - uio->uio_resid;
                                resid = uio->uio_resid;
                        }
                        if (dontroute) {
                                SOCK_LOCK(so);
                                so->so_options |= SO_DONTROUTE;
                                SOCK_UNLOCK(so);
                        }
                        /*
                         * XXX all the SBS_CANTSENDMORE checks previously
                         * done could be out of date.  We could have received
                         * a reset packet in an interrupt or maybe we slept
                         * while doing page faults in uiomove() etc.  We
                         * could probably recheck again inside the locking
                         * protection here, but there are probably other
                         * places that this also happens.  We must rethink
                         * this.
                         */
                        VNET_SO_ASSERT(so);

                        pr_send_flag = (flags & MSG_OOB) ? PRUS_OOB :
                        /*
                         * If the user set MSG_EOF, the protocol understands
                         * this flag and nothing left to send then use
                         * PRU_SEND_EOF instead of PRU_SEND.
                         */
                            ((flags & MSG_EOF) &&
                             (so->so_proto->pr_flags & PR_IMPLOPCL) &&
                             (resid <= 0)) ?
                                PRUS_EOF :
                        /* If there is more to send set PRUS_MORETOCOME. */
                            (flags & MSG_MORETOCOME) ||
                            (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0;

#ifdef KERN_TLS
                        pr_send_flag |= tls_send_flag;
#endif

                        error = so->so_proto->pr_send(so, pr_send_flag, top,
                            addr, control, td);

                        if (dontroute) {
                                SOCK_LOCK(so);
                                so->so_options &= ~SO_DONTROUTE;
                                SOCK_UNLOCK(so);
                        }

#ifdef KERN_TLS
                        if (tls != NULL && tls->mode == TCP_TLS_MODE_SW) {
                                if (error != 0) {
                                        m_freem(top);
                                        top = NULL;
                                } else {
                                        soref(so);
                                        ktls_enqueue(top, so, tls_enq_cnt);
                                }
                        }
#endif
                        clen = 0;
                        control = NULL;
                        top = NULL;
                        if (error)
                                goto out;
                } while (resid && space > 0);
        } while (resid);

out:
#ifdef KERN_TLS
        if (tls != NULL)
                ktls_free(tls);
#endif
        if (top != NULL)
                m_freem(top);
        if (control != NULL)
                m_freem(control);
        return (error);
}

int
sosend_generic(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
{
        int error;

        error = SOCK_IO_SEND_LOCK(so, SBLOCKWAIT(flags));
        if (error)
                return (error);
        error = sosend_generic_locked(so, addr, uio, top, control, flags, td);
        SOCK_IO_SEND_UNLOCK(so);
        return (error);
}

/*
 * Send to a socket from a kernel thread.
 *
 * XXXGL: in almost all cases uio is NULL and the mbuf is supplied.
 * Exception is nfs/bootp_subr.c.  It is arguable that the VNET context needs
 * to be set at all.  This function should just boil down to a static inline
 * calling the protocol method.
 */
int
sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *top, struct mbuf *control, int flags, struct thread *td)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_sosend(so, addr, uio,
            top, control, flags, td);
        CURVNET_RESTORE();
        return (error);
}

/*
 * send(2), write(2) or aio_write(2) on a socket.
 */
int
sousrsend(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *control, int flags, struct proc *userproc)
{
        struct thread *td;
        ssize_t len;
        int error;

        td = uio->uio_td;
        len = uio->uio_resid;
        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_sosend(so, addr, uio, NULL, control, flags,
            td);
        CURVNET_RESTORE();
        if (error != 0) {
                /*
                 * Clear transient errors for stream protocols if they made
                 * some progress.  Make exclusion for aio(4) that would
                 * schedule a new write in case of EWOULDBLOCK and clear
                 * error itself.  See soaio_process_job().
                 */
                if (uio->uio_resid != len &&
                    (so->so_proto->pr_flags & PR_ATOMIC) == 0 &&
                    userproc == NULL &&
                    (error == ERESTART || error == EINTR ||
                    error == EWOULDBLOCK))
                        error = 0;
                /* Generation of SIGPIPE can be controlled per socket. */
                if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0 &&
                    (flags & MSG_NOSIGNAL) == 0) {
                        if (userproc != NULL) {
                                /* aio(4) job */
                                PROC_LOCK(userproc);
                                kern_psignal(userproc, SIGPIPE);
                                PROC_UNLOCK(userproc);
                        } else {
                                PROC_LOCK(td->td_proc);
                                tdsignal(td, SIGPIPE);
                                PROC_UNLOCK(td->td_proc);
                        }
                }
        }
        return (error);
}

/*
 * The part of soreceive() that implements reading non-inline out-of-band
 * data from a socket.  For more complete comments, see soreceive(), from
 * which this code originated.
 *
 * Note that soreceive_rcvoob(), unlike the remainder of soreceive(), is
 * unable to return an mbuf chain to the caller.
 */
static int
soreceive_rcvoob(struct socket *so, struct uio *uio, int flags)
{
        struct protosw *pr = so->so_proto;
        struct mbuf *m;
        int error;

        KASSERT(flags & MSG_OOB, ("soreceive_rcvoob: (flags & MSG_OOB) == 0"));
        VNET_SO_ASSERT(so);

        m = m_get(M_WAITOK, MT_DATA);
        error = pr->pr_rcvoob(so, m, flags & MSG_PEEK);
        if (error)
                goto bad;
        do {
                error = uiomove(mtod(m, void *),
                    (int) min(uio->uio_resid, m->m_len), uio);
                m = m_free(m);
        } while (uio->uio_resid && error == 0 && m);
bad:
        if (m != NULL)
                m_freem(m);
        return (error);
}

/*
 * Following replacement or removal of the first mbuf on the first mbuf chain
 * of a socket buffer, push necessary state changes back into the socket
 * buffer so that other consumers see the values consistently.  'nextrecord'
 * is the callers locally stored value of the original value of
 * sb->sb_mb->m_nextpkt which must be restored when the lead mbuf changes.
 * NOTE: 'nextrecord' may be NULL.
 */
static __inline void
sockbuf_pushsync(struct sockbuf *sb, struct mbuf *nextrecord)
{

        SOCKBUF_LOCK_ASSERT(sb);
        /*
         * First, update for the new value of nextrecord.  If necessary, make
         * it the first record.
         */
        if (sb->sb_mb != NULL)
                sb->sb_mb->m_nextpkt = nextrecord;
        else
                sb->sb_mb = nextrecord;

        /*
         * Now update any dependent socket buffer fields to reflect the new
         * state.  This is an expanded inline of SB_EMPTY_FIXUP(), with the
         * addition of a second clause that takes care of the case where
         * sb_mb has been updated, but remains the last record.
         */
        if (sb->sb_mb == NULL) {
                sb->sb_mbtail = NULL;
                sb->sb_lastrecord = NULL;
        } else if (sb->sb_mb->m_nextpkt == NULL)
                sb->sb_lastrecord = sb->sb_mb;
}

/*
 * Implement receive operations on a socket.  We depend on the way that
 * records are added to the sockbuf by sbappend.  In particular, each record
 * (mbufs linked through m_next) must begin with an address if the protocol
 * so specifies, followed by an optional mbuf or mbufs containing ancillary
 * data, and then zero or more mbufs of data.  In order to allow parallelism
 * between network receive and copying to user space, as well as avoid
 * sleeping with a mutex held, we release the socket buffer mutex during the
 * user space copy.  Although the sockbuf is locked, new data may still be
 * appended, and thus we must maintain consistency of the sockbuf during that
 * time.
 *
 * The caller may receive the data as a single mbuf chain by supplying an
 * mbuf **mp for use in returning the chain.  The uio is then used only for
 * the count in uio_resid.
 */
static int
soreceive_generic_locked(struct socket *so, struct sockaddr **psa,
    struct uio *uio, struct mbuf **mp, struct mbuf **controlp, int *flagsp)
{
        struct mbuf *m;
        int flags, error, offset;
        ssize_t len;
        struct protosw *pr = so->so_proto;
        struct mbuf *nextrecord;
        int moff, type = 0;
        ssize_t orig_resid = uio->uio_resid;
        bool report_real_len = false;

        SOCK_IO_RECV_ASSERT_LOCKED(so);

        error = 0;
        if (flagsp != NULL) {
                report_real_len = *flagsp & MSG_TRUNC;
                *flagsp &= ~MSG_TRUNC;
                flags = *flagsp &~ MSG_EOR;
        } else
                flags = 0;

restart:
        SOCKBUF_LOCK(&so->so_rcv);
        m = so->so_rcv.sb_mb;
        /*
         * If we have less data than requested, block awaiting more (subject
         * to any timeout) if:
         *   1. the current count is less than the low water mark, or
         *   2. MSG_DONTWAIT is not set
         */
        if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
            sbavail(&so->so_rcv) < uio->uio_resid) &&
            sbavail(&so->so_rcv) < so->so_rcv.sb_lowat &&
            m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
                KASSERT(m != NULL || !sbavail(&so->so_rcv),
                    ("receive: m == %p sbavail == %u",
                    m, sbavail(&so->so_rcv)));
                if (so->so_error || so->so_rerror) {
                        if (m != NULL)
                                goto dontblock;
                        if (so->so_error)
                                error = so->so_error;
                        else
                                error = so->so_rerror;
                        if ((flags & MSG_PEEK) == 0) {
                                if (so->so_error)
                                        so->so_error = 0;
                                else
                                        so->so_rerror = 0;
                        }
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        goto release;
                }
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
                        if (m != NULL)
                                goto dontblock;
#ifdef KERN_TLS
                        else if (so->so_rcv.sb_tlsdcc == 0 &&
                            so->so_rcv.sb_tlscc == 0) {
#else
                        else {
#endif
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                goto release;
                        }
                }
                for (; m != NULL; m = m->m_next)
                        if (m->m_type == MT_OOBDATA  || (m->m_flags & M_EOR)) {
                                m = so->so_rcv.sb_mb;
                                goto dontblock;
                        }
                if ((so->so_state & (SS_ISCONNECTING | SS_ISCONNECTED |
                    SS_ISDISCONNECTING | SS_ISDISCONNECTED)) == 0 &&
                    (so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        error = ENOTCONN;
                        goto release;
                }
                if (uio->uio_resid == 0 && !report_real_len) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        goto release;
                }
                if ((so->so_state & SS_NBIO) ||
                    (flags & (MSG_DONTWAIT|MSG_NBIO))) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        error = EWOULDBLOCK;
                        goto release;
                }
                SBLASTRECORDCHK(&so->so_rcv);
                SBLASTMBUFCHK(&so->so_rcv);
                error = sbwait(so, SO_RCV);
                SOCKBUF_UNLOCK(&so->so_rcv);
                if (error)
                        goto release;
                goto restart;
        }
dontblock:
        /*
         * From this point onward, we maintain 'nextrecord' as a cache of the
         * pointer to the next record in the socket buffer.  We must keep the
         * various socket buffer pointers and local stack versions of the
         * pointers in sync, pushing out modifications before dropping the
         * socket buffer mutex, and re-reading them when picking it up.
         *
         * Otherwise, we will race with the network stack appending new data
         * or records onto the socket buffer by using inconsistent/stale
         * versions of the field, possibly resulting in socket buffer
         * corruption.
         *
         * By holding the high-level sblock(), we prevent simultaneous
         * readers from pulling off the front of the socket buffer.
         */
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (uio->uio_td)
                uio->uio_td->td_ru.ru_msgrcv++;
        KASSERT(m == so->so_rcv.sb_mb, ("soreceive: m != so->so_rcv.sb_mb"));
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);
        nextrecord = m->m_nextpkt;
        if (pr->pr_flags & PR_ADDR) {
                KASSERT(m->m_type == MT_SONAME,
                    ("m->m_type == %d", m->m_type));
                orig_resid = 0;
                if (psa != NULL)
                        *psa = sodupsockaddr(mtod(m, struct sockaddr *),
                            M_NOWAIT);
                if (flags & MSG_PEEK) {
                        m = m->m_next;
                } else {
                        sbfree(&so->so_rcv, m);
                        so->so_rcv.sb_mb = m_free(m);
                        m = so->so_rcv.sb_mb;
                        sockbuf_pushsync(&so->so_rcv, nextrecord);
                }
        }

        /*
         * Process one or more MT_CONTROL mbufs present before any data mbufs
         * in the first mbuf chain on the socket buffer.  If MSG_PEEK, we
         * just copy the data; if !MSG_PEEK, we call into the protocol to
         * perform externalization (or freeing if controlp == NULL).
         */
        if (m != NULL && m->m_type == MT_CONTROL) {
                struct mbuf *cm = NULL, *cmn;
                struct mbuf **cme = &cm;
#ifdef KERN_TLS
                struct cmsghdr *cmsg;
                struct tls_get_record tgr;

                /*
                 * For MSG_TLSAPPDATA, check for an alert record.
                 * If found, return ENXIO without removing
                 * it from the receive queue.  This allows a subsequent
                 * call without MSG_TLSAPPDATA to receive it.
                 * Note that, for TLS, there should only be a single
                 * control mbuf with the TLS_GET_RECORD message in it.
                 */
                if (flags & MSG_TLSAPPDATA) {
                        cmsg = mtod(m, struct cmsghdr *);
                        if (cmsg->cmsg_type == TLS_GET_RECORD &&
                            cmsg->cmsg_len == CMSG_LEN(sizeof(tgr))) {
                                memcpy(&tgr, CMSG_DATA(cmsg), sizeof(tgr));
                                if (__predict_false(tgr.tls_type ==
                                    TLS_RLTYPE_ALERT)) {
                                        SOCKBUF_UNLOCK(&so->so_rcv);
                                        error = ENXIO;
                                        goto release;
                                }
                        }
                }
#endif

                do {
                        if (flags & MSG_PEEK) {
                                if (controlp != NULL) {
                                        *controlp = m_copym(m, 0, m->m_len,
                                            M_NOWAIT);
                                        controlp = &(*controlp)->m_next;
                                }
                                m = m->m_next;
                        } else {
                                sbfree(&so->so_rcv, m);
                                so->so_rcv.sb_mb = m->m_next;
                                m->m_next = NULL;
                                *cme = m;
                                cme = &(*cme)->m_next;
                                m = so->so_rcv.sb_mb;
                        }
                } while (m != NULL && m->m_type == MT_CONTROL);
                if ((flags & MSG_PEEK) == 0)
                        sockbuf_pushsync(&so->so_rcv, nextrecord);
                while (cm != NULL) {
                        cmn = cm->m_next;
                        cm->m_next = NULL;
                        if (controlp != NULL)
                                *controlp = cm;
                        else
                                m_freem(cm);
                        if (controlp != NULL) {
                                while (*controlp != NULL)
                                        controlp = &(*controlp)->m_next;
                        }
                        cm = cmn;
                }
                if (m != NULL)
                        nextrecord = so->so_rcv.sb_mb->m_nextpkt;
                else
                        nextrecord = so->so_rcv.sb_mb;
                orig_resid = 0;
        }
        if (m != NULL) {
                if ((flags & MSG_PEEK) == 0) {
                        KASSERT(m->m_nextpkt == nextrecord,
                            ("soreceive: post-control, nextrecord !sync"));
                        if (nextrecord == NULL) {
                                KASSERT(so->so_rcv.sb_mb == m,
                                    ("soreceive: post-control, sb_mb!=m"));
                                KASSERT(so->so_rcv.sb_lastrecord == m,
                                    ("soreceive: post-control, lastrecord!=m"));
                        }
                }
                type = m->m_type;
                if (type == MT_OOBDATA)
                        flags |= MSG_OOB;
        } else {
                if ((flags & MSG_PEEK) == 0) {
                        KASSERT(so->so_rcv.sb_mb == nextrecord,
                            ("soreceive: sb_mb != nextrecord"));
                        if (so->so_rcv.sb_mb == NULL) {
                                KASSERT(so->so_rcv.sb_lastrecord == NULL,
                                    ("soreceive: sb_lastercord != NULL"));
                        }
                }
        }
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);

        /*
         * Now continue to read any data mbufs off of the head of the socket
         * buffer until the read request is satisfied.  Note that 'type' is
         * used to store the type of any mbuf reads that have happened so far
         * such that soreceive() can stop reading if the type changes, which
         * causes soreceive() to return only one of regular data and inline
         * out-of-band data in a single socket receive operation.
         */
        moff = 0;
        offset = 0;
        while (m != NULL && !(m->m_flags & M_NOTREADY) && uio->uio_resid > 0 &&
            error == 0) {
                /*
                 * If the type of mbuf has changed since the last mbuf
                 * examined ('type'), end the receive operation.
                 */
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (m->m_type == MT_OOBDATA || m->m_type == MT_CONTROL) {
                        if (type != m->m_type)
                                break;
                } else if (type == MT_OOBDATA)
                        break;
                else
                    KASSERT(m->m_type == MT_DATA,
                        ("m->m_type == %d", m->m_type));
                so->so_rcv.sb_state &= ~SBS_RCVATMARK;
                len = uio->uio_resid;
                if (so->so_oobmark && len > so->so_oobmark - offset)
                        len = so->so_oobmark - offset;
                if (len > m->m_len - moff)
                        len = m->m_len - moff;
                /*
                 * If mp is set, just pass back the mbufs.  Otherwise copy
                 * them out via the uio, then free.  Sockbuf must be
                 * consistent here (points to current mbuf, it points to next
                 * record) when we drop priority; we must note any additions
                 * to the sockbuf when we block interrupts again.
                 */
                if (mp == NULL) {
                        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                        SBLASTRECORDCHK(&so->so_rcv);
                        SBLASTMBUFCHK(&so->so_rcv);
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        if ((m->m_flags & M_EXTPG) != 0)
                                error = m_unmapped_uiomove(m, moff, uio,
                                    (int)len);
                        else
                                error = uiomove(mtod(m, char *) + moff,
                                    (int)len, uio);
                        SOCKBUF_LOCK(&so->so_rcv);
                        if (error) {
                                /*
                                 * The MT_SONAME mbuf has already been removed
                                 * from the record, so it is necessary to
                                 * remove the data mbufs, if any, to preserve
                                 * the invariant in the case of PR_ADDR that
                                 * requires MT_SONAME mbufs at the head of
                                 * each record.
                                 */
                                if (pr->pr_flags & PR_ATOMIC &&
                                    ((flags & MSG_PEEK) == 0))
                                        (void)sbdroprecord_locked(&so->so_rcv);
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                goto release;
                        }
                } else
                        uio->uio_resid -= len;
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (len == m->m_len - moff) {
                        if (m->m_flags & M_EOR)
                                flags |= MSG_EOR;
                        if (flags & MSG_PEEK) {
                                m = m->m_next;
                                moff = 0;
                        } else {
                                nextrecord = m->m_nextpkt;
                                sbfree(&so->so_rcv, m);
                                if (mp != NULL) {
                                        m->m_nextpkt = NULL;
                                        *mp = m;
                                        mp = &m->m_next;
                                        so->so_rcv.sb_mb = m = m->m_next;
                                        *mp = NULL;
                                } else {
                                        so->so_rcv.sb_mb = m_free(m);
                                        m = so->so_rcv.sb_mb;
                                }
                                sockbuf_pushsync(&so->so_rcv, nextrecord);
                                SBLASTRECORDCHK(&so->so_rcv);
                                SBLASTMBUFCHK(&so->so_rcv);
                        }
                } else {
                        if (flags & MSG_PEEK)
                                moff += len;
                        else {
                                if (mp != NULL) {
                                        if (flags & MSG_DONTWAIT) {
                                                *mp = m_copym(m, 0, len,
                                                    M_NOWAIT);
                                                if (*mp == NULL) {
                                                        /*
                                                         * m_copym() couldn't
                                                         * allocate an mbuf.
                                                         * Adjust uio_resid back
                                                         * (it was adjusted
                                                         * down by len bytes,
                                                         * which we didn't end
                                                         * up "copying" over).
                                                         */
                                                        uio->uio_resid += len;
                                                        break;
                                                }
                                        } else {
                                                SOCKBUF_UNLOCK(&so->so_rcv);
                                                *mp = m_copym(m, 0, len,
                                                    M_WAITOK);
                                                SOCKBUF_LOCK(&so->so_rcv);
                                        }
                                }
                                sbcut_locked(&so->so_rcv, len);
                        }
                }
                SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                if (so->so_oobmark) {
                        if ((flags & MSG_PEEK) == 0) {
                                so->so_oobmark -= len;
                                if (so->so_oobmark == 0) {
                                        so->so_rcv.sb_state |= SBS_RCVATMARK;
                                        break;
                                }
                        } else {
                                offset += len;
                                if (offset == so->so_oobmark)
                                        break;
                        }
                }
                if (flags & MSG_EOR)
                        break;
                /*
                 * If the MSG_WAITALL flag is set (for non-atomic socket), we
                 * must not quit until "uio->uio_resid == 0" or an error
                 * termination.  If a signal/timeout occurs, return with a
                 * short count but without error.  Keep sockbuf locked
                 * against other readers.
                 */
                while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
                    !sosendallatonce(so) && nextrecord == NULL) {
                        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
                        if (so->so_error || so->so_rerror ||
                            so->so_rcv.sb_state & SBS_CANTRCVMORE)
                                break;
                        /*
                         * Notify the protocol that some data has been
                         * drained before blocking.
                         */
                        if (pr->pr_flags & PR_WANTRCVD) {
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                VNET_SO_ASSERT(so);
                                pr->pr_rcvd(so, flags);
                                SOCKBUF_LOCK(&so->so_rcv);
                                if (__predict_false(so->so_rcv.sb_mb == NULL &&
                                    (so->so_error || so->so_rerror ||
                                    so->so_rcv.sb_state & SBS_CANTRCVMORE)))
                                        break;
                        }
                        SBLASTRECORDCHK(&so->so_rcv);
                        SBLASTMBUFCHK(&so->so_rcv);
                        /*
                         * We could receive some data while was notifying
                         * the protocol. Skip blocking in this case.
                         */
                        if (so->so_rcv.sb_mb == NULL) {
                                error = sbwait(so, SO_RCV);
                                if (error) {
                                        SOCKBUF_UNLOCK(&so->so_rcv);
                                        goto release;
                                }
                        }
                        m = so->so_rcv.sb_mb;
                        if (m != NULL)
                                nextrecord = m->m_nextpkt;
                }
        }

        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (m != NULL && pr->pr_flags & PR_ATOMIC) {
                if (report_real_len)
                        uio->uio_resid -= m_length(m, NULL) - moff;
                flags |= MSG_TRUNC;
                if ((flags & MSG_PEEK) == 0)
                        (void) sbdroprecord_locked(&so->so_rcv);
        }
        if ((flags & MSG_PEEK) == 0) {
                if (m == NULL) {
                        /*
                         * First part is an inline SB_EMPTY_FIXUP().  Second
                         * part makes sure sb_lastrecord is up-to-date if
                         * there is still data in the socket buffer.
                         */
                        so->so_rcv.sb_mb = nextrecord;
                        if (so->so_rcv.sb_mb == NULL) {
                                so->so_rcv.sb_mbtail = NULL;
                                so->so_rcv.sb_lastrecord = NULL;
                        } else if (nextrecord->m_nextpkt == NULL)
                                so->so_rcv.sb_lastrecord = nextrecord;
                }
                SBLASTRECORDCHK(&so->so_rcv);
                SBLASTMBUFCHK(&so->so_rcv);
                /*
                 * If soreceive() is being done from the socket callback,
                 * then don't need to generate ACK to peer to update window,
                 * since ACK will be generated on return to TCP.
                 */
                if (!(flags & MSG_SOCALLBCK) &&
                    (pr->pr_flags & PR_WANTRCVD)) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        VNET_SO_ASSERT(so);
                        pr->pr_rcvd(so, flags);
                        SOCKBUF_LOCK(&so->so_rcv);
                }
        }
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        if (orig_resid == uio->uio_resid && orig_resid &&
            (flags & MSG_EOR) == 0 && (so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0) {
                SOCKBUF_UNLOCK(&so->so_rcv);
                goto restart;
        }
        SOCKBUF_UNLOCK(&so->so_rcv);

        if (flagsp != NULL)
                *flagsp |= flags;
release:
        return (error);
}

int
soreceive_generic(struct socket *so, struct sockaddr **psa, struct uio *uio,
    struct mbuf **mp, struct mbuf **controlp, int *flagsp)
{
        int error, flags;

        if (psa != NULL)
                *psa = NULL;
        if (controlp != NULL)
                *controlp = NULL;
        if (flagsp != NULL) {
                flags = *flagsp;
                if ((flags & MSG_OOB) != 0)
                        return (soreceive_rcvoob(so, uio, flags));
        } else {
                flags = 0;
        }
        if (mp != NULL)
                *mp = NULL;

        error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(flags));
        if (error)
                return (error);
        error = soreceive_generic_locked(so, psa, uio, mp, controlp, flagsp);
        SOCK_IO_RECV_UNLOCK(so);
        return (error);
}

/*
 * Optimized version of soreceive() for stream (TCP) sockets.
 */
static int
soreceive_stream_locked(struct socket *so, struct sockbuf *sb,
    struct sockaddr **psa, struct uio *uio, struct mbuf **mp0,
    struct mbuf **controlp, int flags)
{
        int len = 0, error = 0, oresid;
        struct mbuf *m, *n = NULL;

        SOCK_IO_RECV_ASSERT_LOCKED(so);

        /* Easy one, no space to copyout anything. */
        if (uio->uio_resid == 0)
                return (EINVAL);
        oresid = uio->uio_resid;

        SOCKBUF_LOCK(sb);
        /* We will never ever get anything unless we are or were connected. */
        if (!(so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED))) {
                error = ENOTCONN;
                goto out;
        }

restart:
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);

        /* Abort if socket has reported problems. */
        if (so->so_error) {
                if (sbavail(sb) > 0)
                        goto deliver;
                if (oresid > uio->uio_resid)
                        goto out;
                error = so->so_error;
                if (!(flags & MSG_PEEK))
                        so->so_error = 0;
                goto out;
        }

        /* Door is closed.  Deliver what is left, if any. */
        if (sb->sb_state & SBS_CANTRCVMORE) {
                if (sbavail(sb) > 0)
                        goto deliver;
                else
                        goto out;
        }

        /* Socket buffer is empty and we shall not block. */
        if (sbavail(sb) == 0 &&
            ((so->so_state & SS_NBIO) || (flags & (MSG_DONTWAIT|MSG_NBIO)))) {
                error = EAGAIN;
                goto out;
        }

        /* Socket buffer got some data that we shall deliver now. */
        if (sbavail(sb) > 0 && !(flags & MSG_WAITALL) &&
            ((so->so_state & SS_NBIO) ||
             (flags & (MSG_DONTWAIT|MSG_NBIO)) ||
             sbavail(sb) >= sb->sb_lowat ||
             sbavail(sb) >= uio->uio_resid ||
             sbavail(sb) >= sb->sb_hiwat) ) {
                goto deliver;
        }

        /* On MSG_WAITALL we must wait until all data or error arrives. */
        if ((flags & MSG_WAITALL) &&
            (sbavail(sb) >= uio->uio_resid || sbavail(sb) >= sb->sb_hiwat))
                goto deliver;

        /*
         * Wait and block until (more) data comes in.
         * NB: Drops the sockbuf lock during wait.
         */
        error = sbwait(so, SO_RCV);
        if (error)
                goto out;
        goto restart;

deliver:
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);
        KASSERT(sbavail(sb) > 0, ("%s: sockbuf empty", __func__));
        KASSERT(sb->sb_mb != NULL, ("%s: sb_mb == NULL", __func__));

        /* Statistics. */
        if (uio->uio_td)
                uio->uio_td->td_ru.ru_msgrcv++;

        /* Fill uio until full or current end of socket buffer is reached. */
        len = min(uio->uio_resid, sbavail(sb));
        if (mp0 != NULL) {
                /* Dequeue as many mbufs as possible. */
                if (!(flags & MSG_PEEK) && len >= sb->sb_mb->m_len) {
                        if (*mp0 == NULL)
                                *mp0 = sb->sb_mb;
                        else
                                m_cat(*mp0, sb->sb_mb);
                        for (m = sb->sb_mb;
                             m != NULL && m->m_len <= len;
                             m = m->m_next) {
                                KASSERT(!(m->m_flags & M_NOTREADY),
                                    ("%s: m %p not available", __func__, m));
                                len -= m->m_len;
                                uio->uio_resid -= m->m_len;
                                sbfree(sb, m);
                                n = m;
                        }
                        n->m_next = NULL;
                        sb->sb_mb = m;
                        sb->sb_lastrecord = sb->sb_mb;
                        if (sb->sb_mb == NULL)
                                SB_EMPTY_FIXUP(sb);
                }
                /* Copy the remainder. */
                if (len > 0) {
                        KASSERT(sb->sb_mb != NULL,
                            ("%s: len > 0 && sb->sb_mb empty", __func__));

                        m = m_copym(sb->sb_mb, 0, len, M_NOWAIT);
                        if (m == NULL)
                                len = 0;        /* Don't flush data from sockbuf. */
                        else
                                uio->uio_resid -= len;
                        if (*mp0 != NULL)
                                m_cat(*mp0, m);
                        else
                                *mp0 = m;
                        if (*mp0 == NULL) {
                                error = ENOBUFS;
                                goto out;
                        }
                }
        } else {
                /* NB: Must unlock socket buffer as uiomove may sleep. */
                SOCKBUF_UNLOCK(sb);
                error = m_mbuftouio(uio, sb->sb_mb, len);
                SOCKBUF_LOCK(sb);
                if (error)
                        goto out;
        }
        SBLASTRECORDCHK(sb);
        SBLASTMBUFCHK(sb);

        /*
         * Remove the delivered data from the socket buffer unless we
         * were only peeking.
         */
        if (!(flags & MSG_PEEK)) {
                if (len > 0)
                        sbdrop_locked(sb, len);

                /* Notify protocol that we drained some data. */
                if ((so->so_proto->pr_flags & PR_WANTRCVD) &&
                    (((flags & MSG_WAITALL) && uio->uio_resid > 0) ||
                     !(flags & MSG_SOCALLBCK))) {
                        SOCKBUF_UNLOCK(sb);
                        VNET_SO_ASSERT(so);
                        so->so_proto->pr_rcvd(so, flags);
                        SOCKBUF_LOCK(sb);
                }
        }

        /*
         * For MSG_WAITALL we may have to loop again and wait for
         * more data to come in.
         */
        if ((flags & MSG_WAITALL) && uio->uio_resid > 0)
                goto restart;
out:
        SBLASTRECORDCHK(sb);
        SBLASTMBUFCHK(sb);
        SOCKBUF_UNLOCK(sb);
        return (error);
}

int
soreceive_stream(struct socket *so, struct sockaddr **psa, struct uio *uio,
    struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
        struct sockbuf *sb;
        int error, flags;

        sb = &so->so_rcv;

        /* We only do stream sockets. */
        if (so->so_type != SOCK_STREAM)
                return (EINVAL);
        if (psa != NULL)
                *psa = NULL;
        if (flagsp != NULL)
                flags = *flagsp & ~MSG_EOR;
        else
                flags = 0;
        if (controlp != NULL)
                *controlp = NULL;
        if (flags & MSG_OOB)
                return (soreceive_rcvoob(so, uio, flags));
        if (mp0 != NULL)
                *mp0 = NULL;

#ifdef KERN_TLS
        /*
         * KTLS store TLS records as records with a control message to
         * describe the framing.
         *
         * We check once here before acquiring locks to optimize the
         * common case.
         */
        if (sb->sb_tls_info != NULL)
                return (soreceive_generic(so, psa, uio, mp0, controlp,
                    flagsp));
#endif

        /*
         * Prevent other threads from reading from the socket.  This lock may be
         * dropped in order to sleep waiting for data to arrive.
         */
        error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(flags));
        if (error)
                return (error);
#ifdef KERN_TLS
        if (__predict_false(sb->sb_tls_info != NULL)) {
                SOCK_IO_RECV_UNLOCK(so);
                return (soreceive_generic(so, psa, uio, mp0, controlp,
                    flagsp));
        }
#endif
        error = soreceive_stream_locked(so, sb, psa, uio, mp0, controlp, flags);
        SOCK_IO_RECV_UNLOCK(so);
        return (error);
}

/*
 * Optimized version of soreceive() for simple datagram cases from userspace.
 * Unlike in the stream case, we're able to drop a datagram if copyout()
 * fails, and because we handle datagrams atomically, we don't need to use a
 * sleep lock to prevent I/O interlacing.
 */
int
soreceive_dgram(struct socket *so, struct sockaddr **psa, struct uio *uio,
    struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
        struct mbuf *m, *m2;
        int flags, error;
        ssize_t len;
        struct protosw *pr = so->so_proto;
        struct mbuf *nextrecord;

        if (psa != NULL)
                *psa = NULL;
        if (controlp != NULL)
                *controlp = NULL;
        if (flagsp != NULL)
                flags = *flagsp &~ MSG_EOR;
        else
                flags = 0;

        /*
         * For any complicated cases, fall back to the full
         * soreceive_generic().
         */
        if (mp0 != NULL || (flags & (MSG_PEEK | MSG_OOB | MSG_TRUNC)))
                return (soreceive_generic(so, psa, uio, mp0, controlp,
                    flagsp));

        /*
         * Enforce restrictions on use.
         */
        KASSERT((pr->pr_flags & PR_WANTRCVD) == 0,
            ("soreceive_dgram: wantrcvd"));
        KASSERT(pr->pr_flags & PR_ATOMIC, ("soreceive_dgram: !atomic"));
        KASSERT((so->so_rcv.sb_state & SBS_RCVATMARK) == 0,
            ("soreceive_dgram: SBS_RCVATMARK"));
        KASSERT((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0,
            ("soreceive_dgram: P_CONNREQUIRED"));

        /*
         * Loop blocking while waiting for a datagram.
         */
        SOCKBUF_LOCK(&so->so_rcv);
        while ((m = so->so_rcv.sb_mb) == NULL) {
                KASSERT(sbavail(&so->so_rcv) == 0,
                    ("soreceive_dgram: sb_mb NULL but sbavail %u",
                    sbavail(&so->so_rcv)));
                if (so->so_error) {
                        error = so->so_error;
                        so->so_error = 0;
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        return (error);
                }
                if (so->so_rcv.sb_state & SBS_CANTRCVMORE ||
                    uio->uio_resid == 0) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        return (0);
                }
                if ((so->so_state & SS_NBIO) ||
                    (flags & (MSG_DONTWAIT|MSG_NBIO))) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        return (EWOULDBLOCK);
                }
                SBLASTRECORDCHK(&so->so_rcv);
                SBLASTMBUFCHK(&so->so_rcv);
                error = sbwait(so, SO_RCV);
                if (error) {
                        SOCKBUF_UNLOCK(&so->so_rcv);
                        return (error);
                }
        }
        SOCKBUF_LOCK_ASSERT(&so->so_rcv);

        if (uio->uio_td)
                uio->uio_td->td_ru.ru_msgrcv++;
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);
        nextrecord = m->m_nextpkt;
        if (nextrecord == NULL) {
                KASSERT(so->so_rcv.sb_lastrecord == m,
                    ("soreceive_dgram: lastrecord != m"));
        }

        KASSERT(so->so_rcv.sb_mb->m_nextpkt == nextrecord,
            ("soreceive_dgram: m_nextpkt != nextrecord"));

        /*
         * Pull 'm' and its chain off the front of the packet queue.
         */
        so->so_rcv.sb_mb = NULL;
        sockbuf_pushsync(&so->so_rcv, nextrecord);

        /*
         * Walk 'm's chain and free that many bytes from the socket buffer.
         */
        for (m2 = m; m2 != NULL; m2 = m2->m_next)
                sbfree(&so->so_rcv, m2);

        /*
         * Do a few last checks before we let go of the lock.
         */
        SBLASTRECORDCHK(&so->so_rcv);
        SBLASTMBUFCHK(&so->so_rcv);
        SOCKBUF_UNLOCK(&so->so_rcv);

        if (pr->pr_flags & PR_ADDR) {
                KASSERT(m->m_type == MT_SONAME,
                    ("m->m_type == %d", m->m_type));
                if (psa != NULL)
                        *psa = sodupsockaddr(mtod(m, struct sockaddr *),
                            M_WAITOK);
                m = m_free(m);
        }
        KASSERT(m, ("%s: no data or control after soname", __func__));

        /*
         * Packet to copyout() is now in 'm' and it is disconnected from the
         * queue.
         *
         * Process one or more MT_CONTROL mbufs present before any data mbufs
         * in the first mbuf chain on the socket buffer.  We call into the
         * protocol to perform externalization (or freeing if controlp ==
         * NULL). In some cases there can be only MT_CONTROL mbufs without
         * MT_DATA mbufs.
         */
        if (m->m_type == MT_CONTROL) {
                struct mbuf *cm = NULL, *cmn;
                struct mbuf **cme = &cm;

                do {
                        m2 = m->m_next;
                        m->m_next = NULL;
                        *cme = m;
                        cme = &(*cme)->m_next;
                        m = m2;
                } while (m != NULL && m->m_type == MT_CONTROL);
                while (cm != NULL) {
                        cmn = cm->m_next;
                        cm->m_next = NULL;
                        if (controlp != NULL)
                                *controlp = cm;
                        else
                                m_freem(cm);
                        if (controlp != NULL) {
                                while (*controlp != NULL)
                                        controlp = &(*controlp)->m_next;
                        }
                        cm = cmn;
                }
        }
        KASSERT(m == NULL || m->m_type == MT_DATA,
            ("soreceive_dgram: !data"));
        while (m != NULL && uio->uio_resid > 0) {
                len = uio->uio_resid;
                if (len > m->m_len)
                        len = m->m_len;
                error = uiomove(mtod(m, char *), (int)len, uio);
                if (error) {
                        m_freem(m);
                        return (error);
                }
                if (len == m->m_len)
                        m = m_free(m);
                else {
                        m->m_data += len;
                        m->m_len -= len;
                }
        }
        if (m != NULL) {
                flags |= MSG_TRUNC;
                m_freem(m);
        }
        if (flagsp != NULL)
                *flagsp |= flags;
        return (0);
}

int
soreceive(struct socket *so, struct sockaddr **psa, struct uio *uio,
    struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_soreceive(so, psa, uio, mp0, controlp, flagsp);
        CURVNET_RESTORE();
        return (error);
}

int
soshutdown(struct socket *so, enum shutdown_how how)
{
        int error;

        CURVNET_SET(so->so_vnet);
        error = so->so_proto->pr_shutdown(so, how);
        CURVNET_RESTORE();

        return (error);
}

/*
 * Used by several pr_shutdown implementations that use generic socket buffers.
 */
void
sorflush(struct socket *so)
{
        int error;

        VNET_SO_ASSERT(so);

        /*
         * Dislodge threads currently blocked in receive and wait to acquire
         * a lock against other simultaneous readers before clearing the
         * socket buffer.  Don't let our acquire be interrupted by a signal
         * despite any existing socket disposition on interruptable waiting.
         *
         * The SOCK_IO_RECV_LOCK() is important here as there some pr_soreceive
         * methods that read the top of the socket buffer without acquisition
         * of the socket buffer mutex, assuming that top of the buffer
         * exclusively belongs to the read(2) syscall.  This is handy when
         * performing MSG_PEEK.
         */
        socantrcvmore(so);

        error = SOCK_IO_RECV_LOCK(so, SBL_WAIT | SBL_NOINTR);
        if (error != 0) {
                KASSERT(SOLISTENING(so),
                    ("%s: soiolock(%p) failed", __func__, so));
                return;
        }

        sbrelease(so, SO_RCV);
        SOCK_IO_RECV_UNLOCK(so);

}

int
sosetfib(struct socket *so, int fibnum)
{
        if (fibnum < 0 || fibnum >= rt_numfibs)
                return (EINVAL);

        SOCK_LOCK(so);
        so->so_fibnum = fibnum;
        SOCK_UNLOCK(so);

        return (0);
}

#ifdef SOCKET_HHOOK
/*
 * Wrapper for Socket established helper hook.
 * Parameters: socket, context of the hook point, hook id.
 */
static inline int
hhook_run_socket(struct socket *so, void *hctx, int32_t h_id)
{
        struct socket_hhook_data hhook_data = {
                .so = so,
                .hctx = hctx,
                .m = NULL,
                .status = 0
        };

        CURVNET_SET(so->so_vnet);
        HHOOKS_RUN_IF(V_socket_hhh[h_id], &hhook_data, &so->osd);
        CURVNET_RESTORE();

        /* Ugly but needed, since hhooks return void for now */
        return (hhook_data.status);
}
#endif

/*
 * Perhaps this routine, and sooptcopyout(), below, ought to come in an
 * additional variant to handle the case where the option value needs to be
 * some kind of integer, but not a specific size.  In addition to their use
 * here, these functions are also called by the protocol-level pr_ctloutput()
 * routines.
 */
int
sooptcopyin(struct sockopt *sopt, void *buf, size_t len, size_t minlen)
{
        size_t  valsize;

        /*
         * If the user gives us more than we wanted, we ignore it, but if we
         * don't get the minimum length the caller wants, we return EINVAL.
         * On success, sopt->sopt_valsize is set to however much we actually
         * retrieved.
         */
        if ((valsize = sopt->sopt_valsize) < minlen)
                return EINVAL;
        if (valsize > len)
                sopt->sopt_valsize = valsize = len;

        if (sopt->sopt_td != NULL)
                return (copyin(sopt->sopt_val, buf, valsize));

        bcopy(sopt->sopt_val, buf, valsize);
        return (0);
}

/*
 * Kernel version of setsockopt(2).
 *
 * XXX: optlen is size_t, not socklen_t
 */
int
so_setsockopt(struct socket *so, int level, int optname, void *optval,
    size_t optlen)
{
        struct sockopt sopt;

        sopt.sopt_level = level;
        sopt.sopt_name = optname;
        sopt.sopt_dir = SOPT_SET;
        sopt.sopt_val = optval;
        sopt.sopt_valsize = optlen;
        sopt.sopt_td = NULL;
        return (sosetopt(so, &sopt));
}

int
sosetopt(struct socket *so, struct sockopt *sopt)
{
        int     error, optval;
        struct  linger l;
        struct  timeval tv;
        sbintime_t val, *valp;
        uint32_t val32;
#ifdef MAC
        struct mac extmac;
#endif

        CURVNET_SET(so->so_vnet);
        error = 0;
        if (sopt->sopt_level != SOL_SOCKET) {
                error = so->so_proto->pr_ctloutput(so, sopt);
        } else {
                switch (sopt->sopt_name) {
                case SO_ACCEPTFILTER:
                        error = accept_filt_setopt(so, sopt);
                        if (error)
                                goto bad;
                        break;

                case SO_LINGER:
                        error = sooptcopyin(sopt, &l, sizeof l, sizeof l);
                        if (error)
                                goto bad;
                        if (l.l_linger < 0 ||
                            l.l_linger > USHRT_MAX ||
                            l.l_linger > (INT_MAX / hz)) {
                                error = EDOM;
                                goto bad;
                        }
                        SOCK_LOCK(so);
                        so->so_linger = l.l_linger;
                        if (l.l_onoff)
                                so->so_options |= SO_LINGER;
                        else
                                so->so_options &= ~SO_LINGER;
                        SOCK_UNLOCK(so);
                        break;

                case SO_DEBUG:
                case SO_KEEPALIVE:
                case SO_DONTROUTE:
                case SO_USELOOPBACK:
                case SO_BROADCAST:
                case SO_REUSEADDR:
                case SO_REUSEPORT:
                case SO_REUSEPORT_LB:
                case SO_OOBINLINE:
                case SO_TIMESTAMP:
                case SO_BINTIME:
                case SO_NOSIGPIPE:
                case SO_NO_DDP:
                case SO_NO_OFFLOAD:
                case SO_RERROR:
                        error = sooptcopyin(sopt, &optval, sizeof optval,
                            sizeof optval);
                        if (error)
                                goto bad;
                        SOCK_LOCK(so);
                        if (optval)
                                so->so_options |= sopt->sopt_name;
                        else
                                so->so_options &= ~sopt->sopt_name;
                        SOCK_UNLOCK(so);
                        break;

                case SO_SETFIB:
                        error = so->so_proto->pr_ctloutput(so, sopt);
                        break;

                case SO_USER_COOKIE:
                        error = sooptcopyin(sopt, &val32, sizeof val32,
                            sizeof val32);
                        if (error)
                                goto bad;
                        so->so_user_cookie = val32;
                        break;

                case SO_SNDBUF:
                case SO_RCVBUF:
                case SO_SNDLOWAT:
                case SO_RCVLOWAT:
                        error = so->so_proto->pr_setsbopt(so, sopt);
                        if (error)
                                goto bad;
                        break;

                case SO_SNDTIMEO:
                case SO_RCVTIMEO:
#ifdef COMPAT_FREEBSD32
                        if (SV_CURPROC_FLAG(SV_ILP32)) {
                                struct timeval32 tv32;

                                error = sooptcopyin(sopt, &tv32, sizeof tv32,
                                    sizeof tv32);
                                CP(tv32, tv, tv_sec);
                                CP(tv32, tv, tv_usec);
                        } else
#endif
                                error = sooptcopyin(sopt, &tv, sizeof tv,
                                    sizeof tv);
                        if (error)
                                goto bad;
                        if (tv.tv_sec < 0 || tv.tv_usec < 0 ||
                            tv.tv_usec >= 1000000) {
                                error = EDOM;
                                goto bad;
                        }
                        if (tv.tv_sec > INT32_MAX)
                                val = SBT_MAX;
                        else
                                val = tvtosbt(tv);
                        SOCK_LOCK(so);
                        valp = sopt->sopt_name == SO_SNDTIMEO ?
                            (SOLISTENING(so) ? &so->sol_sbsnd_timeo :
                            &so->so_snd.sb_timeo) :
                            (SOLISTENING(so) ? &so->sol_sbrcv_timeo :
                            &so->so_rcv.sb_timeo);
                        *valp = val;
                        SOCK_UNLOCK(so);
                        break;

                case SO_LABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof extmac,
                            sizeof extmac);
                        if (error)
                                goto bad;
                        error = mac_setsockopt_label(sopt->sopt_td->td_ucred,
                            so, &extmac);
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                case SO_TS_CLOCK:
                        error = sooptcopyin(sopt, &optval, sizeof optval,
                            sizeof optval);
                        if (error)
                                goto bad;
                        if (optval < 0 || optval > SO_TS_CLOCK_MAX) {
                                error = EINVAL;
                                goto bad;
                        }
                        so->so_ts_clock = optval;
                        break;

                case SO_MAX_PACING_RATE:
                        error = sooptcopyin(sopt, &val32, sizeof(val32),
                            sizeof(val32));
                        if (error)
                                goto bad;
                        so->so_max_pacing_rate = val32;
                        break;

                case SO_SPLICE: {
                        struct splice splice;

#ifdef COMPAT_FREEBSD32
                        if (SV_CURPROC_FLAG(SV_ILP32)) {
                                struct splice32 splice32;

                                error = sooptcopyin(sopt, &splice32,
                                    sizeof(splice32), sizeof(splice32));
                                if (error == 0) {
                                        splice.sp_fd = splice32.sp_fd;
                                        splice.sp_max = splice32.sp_max;
                                        CP(splice32.sp_idle, splice.sp_idle,
                                            tv_sec);
                                        CP(splice32.sp_idle, splice.sp_idle,
                                            tv_usec);
                                }
                        } else
#endif
                        {
                                error = sooptcopyin(sopt, &splice,
                                    sizeof(splice), sizeof(splice));
                        }
                        if (error)
                                goto bad;
#ifdef KTRACE
                        if (KTRPOINT(curthread, KTR_STRUCT))
                                ktrsplice(&splice);
#endif

                        error = splice_init();
                        if (error != 0)
                                goto bad;

                        if (splice.sp_fd >= 0) {
                                struct file *fp;
                                struct socket *so2;

                                if (!cap_rights_contains(sopt->sopt_rights,
                                    &cap_recv_rights)) {
                                        error = ENOTCAPABLE;
                                        goto bad;
                                }
                                error = getsock(sopt->sopt_td, splice.sp_fd,
                                    &cap_send_rights, &fp);
                                if (error != 0)
                                        goto bad;
                                so2 = fp->f_data;

                                error = so_splice(so, so2, &splice);
                                fdrop(fp, sopt->sopt_td);
                        } else {
                                error = so_unsplice(so, false);
                        }
                        break;
                }
                default:
#ifdef SOCKET_HHOOK
                        if (V_socket_hhh[HHOOK_SOCKET_OPT]->hhh_nhooks > 0)
                                error = hhook_run_socket(so, sopt,
                                    HHOOK_SOCKET_OPT);
                        else
#endif
                                error = ENOPROTOOPT;
                        break;
                }
                if (error == 0)
                        (void)so->so_proto->pr_ctloutput(so, sopt);
        }
bad:
        CURVNET_RESTORE();
        return (error);
}

/*
 * Helper routine for getsockopt.
 */
int
sooptcopyout(struct sockopt *sopt, const void *buf, size_t len)
{
        int     error;
        size_t  valsize;

        error = 0;

        /*
         * Documented get behavior is that we always return a value, possibly
         * truncated to fit in the user's buffer.  Traditional behavior is
         * that we always tell the user precisely how much we copied, rather
         * than something useful like the total amount we had available for
         * her.  Note that this interface is not idempotent; the entire
         * answer must be generated ahead of time.
         */
        valsize = min(len, sopt->sopt_valsize);
        sopt->sopt_valsize = valsize;
        if (sopt->sopt_val != NULL) {
                if (sopt->sopt_td != NULL)
                        error = copyout(buf, sopt->sopt_val, valsize);
                else
                        bcopy(buf, sopt->sopt_val, valsize);
        }
        return (error);
}

int
sogetopt(struct socket *so, struct sockopt *sopt)
{
        int     error, optval;
        struct  linger l;
        struct  timeval tv;
#ifdef MAC
        struct mac extmac;
#endif

        CURVNET_SET(so->so_vnet);
        error = 0;
        if (sopt->sopt_level != SOL_SOCKET) {
                error = so->so_proto->pr_ctloutput(so, sopt);
                CURVNET_RESTORE();
                return (error);
        } else {
                switch (sopt->sopt_name) {
                case SO_ACCEPTFILTER:
                        error = accept_filt_getopt(so, sopt);
                        break;

                case SO_LINGER:
                        SOCK_LOCK(so);
                        l.l_onoff = so->so_options & SO_LINGER;
                        l.l_linger = so->so_linger;
                        SOCK_UNLOCK(so);
                        error = sooptcopyout(sopt, &l, sizeof l);
                        break;

                case SO_USELOOPBACK:
                case SO_DONTROUTE:
                case SO_DEBUG:
                case SO_KEEPALIVE:
                case SO_REUSEADDR:
                case SO_REUSEPORT:
                case SO_REUSEPORT_LB:
                case SO_BROADCAST:
                case SO_OOBINLINE:
                case SO_ACCEPTCONN:
                case SO_TIMESTAMP:
                case SO_BINTIME:
                case SO_NOSIGPIPE:
                case SO_NO_DDP:
                case SO_NO_OFFLOAD:
                case SO_RERROR:
                        optval = so->so_options & sopt->sopt_name;
integer:
                        error = sooptcopyout(sopt, &optval, sizeof optval);
                        break;

                case SO_FIB:
                        SOCK_LOCK(so);
                        optval = so->so_fibnum;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_DOMAIN:
                        optval = so->so_proto->pr_domain->dom_family;
                        goto integer;

                case SO_TYPE:
                        optval = so->so_type;
                        goto integer;

                case SO_PROTOCOL:
                        optval = so->so_proto->pr_protocol;
                        goto integer;

                case SO_ERROR:
                        SOCK_LOCK(so);
                        if (so->so_error) {
                                optval = so->so_error;
                                so->so_error = 0;
                        } else {
                                optval = so->so_rerror;
                                so->so_rerror = 0;
                        }
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_SNDBUF:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_sbsnd_hiwat :
                            so->so_snd.sb_hiwat;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_RCVBUF:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_sbrcv_hiwat :
                            so->so_rcv.sb_hiwat;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_SNDLOWAT:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_sbsnd_lowat :
                            so->so_snd.sb_lowat;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_RCVLOWAT:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_sbrcv_lowat :
                            so->so_rcv.sb_lowat;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_SNDTIMEO:
                case SO_RCVTIMEO:
                        SOCK_LOCK(so);
                        tv = sbttotv(sopt->sopt_name == SO_SNDTIMEO ?
                            (SOLISTENING(so) ? so->sol_sbsnd_timeo :
                            so->so_snd.sb_timeo) :
                            (SOLISTENING(so) ? so->sol_sbrcv_timeo :
                            so->so_rcv.sb_timeo));
                        SOCK_UNLOCK(so);
#ifdef COMPAT_FREEBSD32
                        if (SV_CURPROC_FLAG(SV_ILP32)) {
                                struct timeval32 tv32;

                                CP(tv, tv32, tv_sec);
                                CP(tv, tv32, tv_usec);
                                error = sooptcopyout(sopt, &tv32, sizeof tv32);
                        } else
#endif
                                error = sooptcopyout(sopt, &tv, sizeof tv);
                        break;

                case SO_LABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof(extmac),
                            sizeof(extmac));
                        if (error)
                                goto bad;
                        error = mac_getsockopt_label(sopt->sopt_td->td_ucred,
                            so, &extmac);
                        if (error)
                                goto bad;
                        /* Don't copy out extmac, it is unchanged. */
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                case SO_PEERLABEL:
#ifdef MAC
                        error = sooptcopyin(sopt, &extmac, sizeof(extmac),
                            sizeof(extmac));
                        if (error)
                                goto bad;
                        error = mac_getsockopt_peerlabel(
                            sopt->sopt_td->td_ucred, so, &extmac);
                        if (error)
                                goto bad;
                        /* Don't copy out extmac, it is unchanged. */
#else
                        error = EOPNOTSUPP;
#endif
                        break;

                case SO_LISTENQLIMIT:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_qlimit : 0;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_LISTENQLEN:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_qlen : 0;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_LISTENINCQLEN:
                        SOCK_LOCK(so);
                        optval = SOLISTENING(so) ? so->sol_incqlen : 0;
                        SOCK_UNLOCK(so);
                        goto integer;

                case SO_TS_CLOCK:
                        optval = so->so_ts_clock;
                        goto integer;

                case SO_MAX_PACING_RATE:
                        optval = so->so_max_pacing_rate;
                        goto integer;

                case SO_SPLICE: {
                        off_t n;

                        /*
                         * Acquire the I/O lock to serialize with
                         * so_splice_xfer().  This is not required for
                         * correctness, but makes testing simpler: once a byte
                         * has been transmitted to the sink and observed (e.g.,
                         * by reading from the socket to which the sink is
                         * connected), a subsequent getsockopt(SO_SPLICE) will
                         * return an up-to-date value.
                         */
                        error = SOCK_IO_RECV_LOCK(so, SBL_WAIT);
                        if (error != 0)
                                goto bad;
                        SOCK_LOCK(so);
                        if (SOLISTENING(so)) {
                                n = 0;
                        } else {
                                n = so->so_splice_sent;
                        }
                        SOCK_UNLOCK(so);
                        SOCK_IO_RECV_UNLOCK(so);
                        error = sooptcopyout(sopt, &n, sizeof(n));
                        break;
                }

                default:
#ifdef SOCKET_HHOOK
                        if (V_socket_hhh[HHOOK_SOCKET_OPT]->hhh_nhooks > 0)
                                error = hhook_run_socket(so, sopt,
                                    HHOOK_SOCKET_OPT);
                        else
#endif
                                error = ENOPROTOOPT;
                        break;
                }
        }
bad:
        CURVNET_RESTORE();
        return (error);
}

int
soopt_getm(struct sockopt *sopt, struct mbuf **mp)
{
        struct mbuf *m, *m_prev;
        int sopt_size = sopt->sopt_valsize;

        MGET(m, sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
        if (m == NULL)
                return ENOBUFS;
        if (sopt_size > MLEN) {
                MCLGET(m, sopt->sopt_td ? M_WAITOK : M_NOWAIT);
                if ((m->m_flags & M_EXT) == 0) {
                        m_free(m);
                        return ENOBUFS;
                }
                m->m_len = min(MCLBYTES, sopt_size);
        } else {
                m->m_len = min(MLEN, sopt_size);
        }
        sopt_size -= m->m_len;
        *mp = m;
        m_prev = m;

        while (sopt_size) {
                MGET(m, sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA);
                if (m == NULL) {
                        m_freem(*mp);
                        return ENOBUFS;
                }
                if (sopt_size > MLEN) {
                        MCLGET(m, sopt->sopt_td != NULL ? M_WAITOK :
                            M_NOWAIT);
                        if ((m->m_flags & M_EXT) == 0) {
                                m_freem(m);
                                m_freem(*mp);
                                return ENOBUFS;
                        }
                        m->m_len = min(MCLBYTES, sopt_size);
                } else {
                        m->m_len = min(MLEN, sopt_size);
                }
                sopt_size -= m->m_len;
                m_prev->m_next = m;
                m_prev = m;
        }
        return (0);
}

int
soopt_mcopyin(struct sockopt *sopt, struct mbuf *m)
{
        struct mbuf *m0 = m;

        if (sopt->sopt_val == NULL)
                return (0);
        while (m != NULL && sopt->sopt_valsize >= m->m_len) {
                if (sopt->sopt_td != NULL) {
                        int error;

                        error = copyin(sopt->sopt_val, mtod(m, char *),
                            m->m_len);
                        if (error != 0) {
                                m_freem(m0);
                                return(error);
                        }
                } else
                        bcopy(sopt->sopt_val, mtod(m, char *), m->m_len);
                sopt->sopt_valsize -= m->m_len;
                sopt->sopt_val = (char *)sopt->sopt_val + m->m_len;
                m = m->m_next;
        }
        if (m != NULL) /* should be allocated enoughly at ip6_sooptmcopyin() */
                panic("ip6_sooptmcopyin");
        return (0);
}

int
soopt_mcopyout(struct sockopt *sopt, struct mbuf *m)
{
        struct mbuf *m0 = m;
        size_t valsize = 0;

        if (sopt->sopt_val == NULL)
                return (0);
        while (m != NULL && sopt->sopt_valsize >= m->m_len) {
                if (sopt->sopt_td != NULL) {
                        int error;

                        error = copyout(mtod(m, char *), sopt->sopt_val,
                            m->m_len);
                        if (error != 0) {
                                m_freem(m0);
                                return(error);
                        }
                } else
                        bcopy(mtod(m, char *), sopt->sopt_val, m->m_len);
                sopt->sopt_valsize -= m->m_len;
                sopt->sopt_val = (char *)sopt->sopt_val + m->m_len;
                valsize += m->m_len;
                m = m->m_next;
        }
        if (m != NULL) {
                /* enough soopt buffer should be given from user-land */
                m_freem(m0);
                return(EINVAL);
        }
        sopt->sopt_valsize = valsize;
        return (0);
}

/*
 * sohasoutofband(): protocol notifies socket layer of the arrival of new
 * out-of-band data, which will then notify socket consumers.
 */
void
sohasoutofband(struct socket *so)
{

        if (so->so_sigio != NULL)
                pgsigio(&so->so_sigio, SIGURG, 0);
        selwakeuppri(&so->so_rdsel, PSOCK);
}

int
sopoll_generic(struct socket *so, int events, struct thread *td)
{
        int revents;

        SOCK_LOCK(so);
        if (SOLISTENING(so)) {
                if (!(events & (POLLIN | POLLRDNORM)))
                        revents = 0;
                else if (!TAILQ_EMPTY(&so->sol_comp))
                        revents = events & (POLLIN | POLLRDNORM);
                else if ((events & POLLINIGNEOF) == 0 && so->so_error)
                        revents = (events & (POLLIN | POLLRDNORM)) | POLLHUP;
                else {
                        selrecord(td, &so->so_rdsel);
                        revents = 0;
                }
        } else {
                revents = 0;
                SOCK_SENDBUF_LOCK(so);
                SOCK_RECVBUF_LOCK(so);
                if (events & (POLLIN | POLLRDNORM))
                        if (soreadabledata(so) && !isspliced(so))
                                revents |= events & (POLLIN | POLLRDNORM);
                if (events & (POLLOUT | POLLWRNORM))
                        if (sowriteable(so) && !issplicedback(so))
                                revents |= events & (POLLOUT | POLLWRNORM);
                if (events & (POLLPRI | POLLRDBAND))
                        if (so->so_oobmark ||
                            (so->so_rcv.sb_state & SBS_RCVATMARK))
                                revents |= events & (POLLPRI | POLLRDBAND);
                if ((events & POLLINIGNEOF) == 0) {
                        if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
                                revents |= events & (POLLIN | POLLRDNORM);
                                if (so->so_snd.sb_state & SBS_CANTSENDMORE)
                                        revents |= POLLHUP;
                        }
                }
                if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
                        revents |= events & POLLRDHUP;
                if (revents == 0) {
                        if (events &
                            (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND | POLLRDHUP)) {
                                selrecord(td, &so->so_rdsel);
                                so->so_rcv.sb_flags |= SB_SEL;
                        }
                        if (events & (POLLOUT | POLLWRNORM)) {
                                selrecord(td, &so->so_wrsel);
                                so->so_snd.sb_flags |= SB_SEL;
                        }
                }
                SOCK_RECVBUF_UNLOCK(so);
                SOCK_SENDBUF_UNLOCK(so);
        }
        SOCK_UNLOCK(so);
        return (revents);
}

int
sokqfilter_generic(struct socket *so, struct knote *kn)
{
        struct sockbuf *sb;
        sb_which which;
        struct knlist *knl;

        switch (kn->kn_filter) {
        case EVFILT_READ:
                kn->kn_fop = &soread_filtops;
                knl = &so->so_rdsel.si_note;
                sb = &so->so_rcv;
                which = SO_RCV;
                break;
        case EVFILT_WRITE:
                kn->kn_fop = &sowrite_filtops;
                knl = &so->so_wrsel.si_note;
                sb = &so->so_snd;
                which = SO_SND;
                break;
        case EVFILT_EMPTY:
                kn->kn_fop = &soempty_filtops;
                knl = &so->so_wrsel.si_note;
                sb = &so->so_snd;
                which = SO_SND;
                break;
        default:
                return (EINVAL);
        }

        SOCK_LOCK(so);
        if (SOLISTENING(so)) {
                knlist_add(knl, kn, 1);
        } else {
                SOCK_BUF_LOCK(so, which);
                knlist_add(knl, kn, 1);
                sb->sb_flags |= SB_KNOTE;
                if ((kn->kn_sfflags & NOTE_LOWAT) &&
                    (sb->sb_flags & SB_AUTOLOWAT))
                        sb->sb_flags &= ~SB_AUTOLOWAT;
                SOCK_BUF_UNLOCK(so, which);
        }
        SOCK_UNLOCK(so);
        return (0);
}

static void
filt_sordetach(struct knote *kn)
{
        struct socket *so = kn->kn_fp->f_data;

        so_rdknl_lock(so);
        knlist_remove(&so->so_rdsel.si_note, kn, 1);
        if (!SOLISTENING(so) && knlist_empty(&so->so_rdsel.si_note))
                so->so_rcv.sb_flags &= ~SB_KNOTE;
        so_rdknl_unlock(so);
}

/*ARGSUSED*/
static int
filt_soread(struct knote *kn, long hint)
{
        struct socket *so;

        so = kn->kn_fp->f_data;

        if (SOLISTENING(so)) {
                SOCK_LOCK_ASSERT(so);
                kn->kn_data = so->sol_qlen;
                if (so->so_error) {
                        kn->kn_flags |= EV_EOF;
                        kn->kn_fflags = so->so_error;
                        return (1);
                }
                return (!TAILQ_EMPTY(&so->sol_comp));
        }

        if ((so->so_rcv.sb_flags & SB_SPLICED) != 0)
                return (0);

        SOCK_RECVBUF_LOCK_ASSERT(so);

        kn->kn_data = sbavail(&so->so_rcv) - so->so_rcv.sb_ctl;
        if (so->so_rcv.sb_state & SBS_CANTRCVMORE) {
                kn->kn_flags |= EV_EOF;
                kn->kn_fflags = so->so_error;
                return (1);
        } else if (so->so_error || so->so_rerror)
                return (1);

        if (kn->kn_sfflags & NOTE_LOWAT) {
                if (kn->kn_data >= kn->kn_sdata)
                        return (1);
        } else if (sbavail(&so->so_rcv) >= so->so_rcv.sb_lowat)
                return (1);

#ifdef SOCKET_HHOOK
        /* This hook returning non-zero indicates an event, not error */
        return (hhook_run_socket(so, NULL, HHOOK_FILT_SOREAD));
#else
        return (0);
#endif
}

static void
filt_sowdetach(struct knote *kn)
{
        struct socket *so = kn->kn_fp->f_data;

        so_wrknl_lock(so);
        knlist_remove(&so->so_wrsel.si_note, kn, 1);
        if (!SOLISTENING(so) && knlist_empty(&so->so_wrsel.si_note))
                so->so_snd.sb_flags &= ~SB_KNOTE;
        so_wrknl_unlock(so);
}

/*ARGSUSED*/
static int
filt_sowrite(struct knote *kn, long hint)
{
        struct socket *so;

        so = kn->kn_fp->f_data;

        if (SOLISTENING(so))
                return (0);

        SOCK_SENDBUF_LOCK_ASSERT(so);
        kn->kn_data = sbspace(&so->so_snd);

#ifdef SOCKET_HHOOK
        hhook_run_socket(so, kn, HHOOK_FILT_SOWRITE);
#endif

        if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
                kn->kn_flags |= EV_EOF;
                kn->kn_fflags = so->so_error;
                return (1);
        } else if (so->so_error)        /* temporary udp error */
                return (1);
        else if (((so->so_state & SS_ISCONNECTED) == 0) &&
            (so->so_proto->pr_flags & PR_CONNREQUIRED))
                return (0);
        else if (kn->kn_sfflags & NOTE_LOWAT)
                return (kn->kn_data >= kn->kn_sdata);
        else
                return (kn->kn_data >= so->so_snd.sb_lowat);
}

static int
filt_soempty(struct knote *kn, long hint)
{
        struct socket *so;

        so = kn->kn_fp->f_data;

        if (SOLISTENING(so))
                return (1);

        SOCK_SENDBUF_LOCK_ASSERT(so);
        kn->kn_data = sbused(&so->so_snd);

        if (kn->kn_data == 0)
                return (1);
        else
                return (0);
}

int
socheckuid(struct socket *so, uid_t uid)
{

        if (so == NULL)
                return (EPERM);
        if (so->so_cred->cr_uid != uid)
                return (EPERM);
        return (0);
}

/*
 * These functions are used by protocols to notify the socket layer (and its
 * consumers) of state changes in the sockets driven by protocol-side events.
 */

/*
 * Procedures to manipulate state flags of socket and do appropriate wakeups.
 *
 * Normal sequence from the active (originating) side is that
 * soisconnecting() is called during processing of connect() call, resulting
 * in an eventual call to soisconnected() if/when the connection is
 * established.  When the connection is torn down soisdisconnecting() is
 * called during processing of disconnect() call, and soisdisconnected() is
 * called when the connection to the peer is totally severed.  The semantics
 * of these routines are such that connectionless protocols can call
 * soisconnected() and soisdisconnected() only, bypassing the in-progress
 * calls when setting up a ``connection'' takes no time.
 *
 * From the passive side, a socket is created with two queues of sockets:
 * so_incomp for connections in progress and so_comp for connections already
 * made and awaiting user acceptance.  As a protocol is preparing incoming
 * connections, it creates a socket structure queued on so_incomp by calling
 * sonewconn().  When the connection is established, soisconnected() is
 * called, and transfers the socket structure to so_comp, making it available
 * to accept().
 *
 * If a socket is closed with sockets on either so_incomp or so_comp, these
 * sockets are dropped.
 *
 * If higher-level protocols are implemented in the kernel, the wakeups done
 * here will sometimes cause software-interrupt process scheduling.
 */
void
soisconnecting(struct socket *so)
{

        SOCK_LOCK(so);
        so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
        so->so_state |= SS_ISCONNECTING;
        SOCK_UNLOCK(so);
}

void
soisconnected(struct socket *so)
{
        bool last __diagused;

        SOCK_LOCK(so);
        so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING);
        so->so_state |= SS_ISCONNECTED;

        if (so->so_qstate == SQ_INCOMP) {
                struct socket *head = so->so_listen;
                int ret;

                KASSERT(head, ("%s: so %p on incomp of NULL", __func__, so));
                /*
                 * Promoting a socket from incomplete queue to complete, we
                 * need to go through reverse order of locking.  We first do
                 * trylock, and if that doesn't succeed, we go the hard way
                 * leaving a reference and rechecking consistency after proper
                 * locking.
                 */
                if (__predict_false(SOLISTEN_TRYLOCK(head) == 0)) {
                        soref(head);
                        SOCK_UNLOCK(so);
                        SOLISTEN_LOCK(head);
                        SOCK_LOCK(so);
                        if (__predict_false(head != so->so_listen)) {
                                /*
                                 * The socket went off the listen queue,
                                 * should be lost race to close(2) of sol.
                                 * The socket is about to soabort().
                                 */
                                SOCK_UNLOCK(so);
                                sorele_locked(head);
                                return;
                        }
                        last = refcount_release(&head->so_count);
                        KASSERT(!last, ("%s: released last reference for %p",
                            __func__, head));
                }
again:
                if ((so->so_options & SO_ACCEPTFILTER) == 0) {
                        TAILQ_REMOVE(&head->sol_incomp, so, so_list);
                        head->sol_incqlen--;
                        TAILQ_INSERT_TAIL(&head->sol_comp, so, so_list);
                        head->sol_qlen++;
                        so->so_qstate = SQ_COMP;
                        SOCK_UNLOCK(so);
                        solisten_wakeup(head);  /* unlocks */
                } else {
                        SOCK_RECVBUF_LOCK(so);
                        soupcall_set(so, SO_RCV,
                            head->sol_accept_filter->accf_callback,
                            head->sol_accept_filter_arg);
                        so->so_options &= ~SO_ACCEPTFILTER;
                        ret = head->sol_accept_filter->accf_callback(so,
                            head->sol_accept_filter_arg, M_NOWAIT);
                        if (ret == SU_ISCONNECTED) {
                                soupcall_clear(so, SO_RCV);
                                SOCK_RECVBUF_UNLOCK(so);
                                goto again;
                        }
                        SOCK_RECVBUF_UNLOCK(so);
                        SOCK_UNLOCK(so);
                        SOLISTEN_UNLOCK(head);
                }
                return;
        }
        SOCK_UNLOCK(so);
        wakeup(&so->so_timeo);
        sorwakeup(so);
        sowwakeup(so);
}

void
soisdisconnecting(struct socket *so)
{

        SOCK_LOCK(so);
        so->so_state &= ~SS_ISCONNECTING;
        so->so_state |= SS_ISDISCONNECTING;

        if (!SOLISTENING(so)) {
                SOCK_RECVBUF_LOCK(so);
                socantrcvmore_locked(so);
                SOCK_SENDBUF_LOCK(so);
                socantsendmore_locked(so);
        }
        SOCK_UNLOCK(so);
        wakeup(&so->so_timeo);
}

void
soisdisconnected(struct socket *so)
{

        SOCK_LOCK(so);

        /*
         * There is at least one reader of so_state that does not
         * acquire socket lock, namely soreceive_generic().  Ensure
         * that it never sees all flags that track connection status
         * cleared, by ordering the update with a barrier semantic of
         * our release thread fence.
         */
        so->so_state |= SS_ISDISCONNECTED;
        atomic_thread_fence_rel();
        so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);

        if (!SOLISTENING(so)) {
                SOCK_UNLOCK(so);
                SOCK_RECVBUF_LOCK(so);
                socantrcvmore_locked(so);
                SOCK_SENDBUF_LOCK(so);
                sbdrop_locked(&so->so_snd, sbused(&so->so_snd));
                socantsendmore_locked(so);
        } else
                SOCK_UNLOCK(so);
        wakeup(&so->so_timeo);
}

int
soiolock(struct socket *so, struct sx *sx, int flags)
{
        int error;

        KASSERT((flags & SBL_VALID) == flags,
            ("soiolock: invalid flags %#x", flags));

        if ((flags & SBL_WAIT) != 0) {
                if ((flags & SBL_NOINTR) != 0) {
                        sx_xlock(sx);
                } else {
                        error = sx_xlock_sig(sx);
                        if (error != 0)
                                return (error);
                }
        } else if (!sx_try_xlock(sx)) {
                return (EWOULDBLOCK);
        }

        if (__predict_false(SOLISTENING(so))) {
                sx_xunlock(sx);
                return (ENOTCONN);
        }
        return (0);
}

void
soiounlock(struct sx *sx)
{
        sx_xunlock(sx);
}

/*
 * Make a copy of a sockaddr in a malloced buffer of type M_SONAME.
 */
struct sockaddr *
sodupsockaddr(const struct sockaddr *sa, int mflags)
{
        struct sockaddr *sa2;

        sa2 = malloc(sa->sa_len, M_SONAME, mflags);
        if (sa2)
                bcopy(sa, sa2, sa->sa_len);
        return sa2;
}

/*
 * Register per-socket destructor.
 */
void
sodtor_set(struct socket *so, so_dtor_t *func)
{

        SOCK_LOCK_ASSERT(so);
        so->so_dtor = func;
}

/*
 * Register per-socket buffer upcalls.
 */
void
soupcall_set(struct socket *so, sb_which which, so_upcall_t func, void *arg)
{
        struct sockbuf *sb;

        KASSERT(!SOLISTENING(so), ("%s: so %p listening", __func__, so));

        switch (which) {
        case SO_RCV:
                sb = &so->so_rcv;
                break;
        case SO_SND:
                sb = &so->so_snd;
                break;
        }
        SOCK_BUF_LOCK_ASSERT(so, which);
        sb->sb_upcall = func;
        sb->sb_upcallarg = arg;
        sb->sb_flags |= SB_UPCALL;
}

void
soupcall_clear(struct socket *so, sb_which which)
{
        struct sockbuf *sb;

        KASSERT(!SOLISTENING(so), ("%s: so %p listening", __func__, so));

        switch (which) {
        case SO_RCV:
                sb = &so->so_rcv;
                break;
        case SO_SND:
                sb = &so->so_snd;
                break;
        }
        SOCK_BUF_LOCK_ASSERT(so, which);
        KASSERT(sb->sb_upcall != NULL,
            ("%s: so %p no upcall to clear", __func__, so));
        sb->sb_upcall = NULL;
        sb->sb_upcallarg = NULL;
        sb->sb_flags &= ~SB_UPCALL;
}

void
solisten_upcall_set(struct socket *so, so_upcall_t func, void *arg)
{

        SOLISTEN_LOCK_ASSERT(so);
        so->sol_upcall = func;
        so->sol_upcallarg = arg;
}

static void
so_rdknl_lock(void *arg)
{
        struct socket *so = arg;

retry:
        if (SOLISTENING(so)) {
                SOLISTEN_LOCK(so);
        } else {
                SOCK_RECVBUF_LOCK(so);
                if (__predict_false(SOLISTENING(so))) {
                        SOCK_RECVBUF_UNLOCK(so);
                        goto retry;
                }
        }
}

static void
so_rdknl_unlock(void *arg)
{
        struct socket *so = arg;

        if (SOLISTENING(so))
                SOLISTEN_UNLOCK(so);
        else
                SOCK_RECVBUF_UNLOCK(so);
}

static void
so_rdknl_assert_lock(void *arg, int what)
{
        struct socket *so = arg;

        if (what == LA_LOCKED) {
                if (SOLISTENING(so))
                        SOLISTEN_LOCK_ASSERT(so);
                else
                        SOCK_RECVBUF_LOCK_ASSERT(so);
        } else {
                if (SOLISTENING(so))
                        SOLISTEN_UNLOCK_ASSERT(so);
                else
                        SOCK_RECVBUF_UNLOCK_ASSERT(so);
        }
}

static void
so_wrknl_lock(void *arg)
{
        struct socket *so = arg;

retry:
        if (SOLISTENING(so)) {
                SOLISTEN_LOCK(so);
        } else {
                SOCK_SENDBUF_LOCK(so);
                if (__predict_false(SOLISTENING(so))) {
                        SOCK_SENDBUF_UNLOCK(so);
                        goto retry;
                }
        }
}

static void
so_wrknl_unlock(void *arg)
{
        struct socket *so = arg;

        if (SOLISTENING(so))
                SOLISTEN_UNLOCK(so);
        else
                SOCK_SENDBUF_UNLOCK(so);
}

static void
so_wrknl_assert_lock(void *arg, int what)
{
        struct socket *so = arg;

        if (what == LA_LOCKED) {
                if (SOLISTENING(so))
                        SOLISTEN_LOCK_ASSERT(so);
                else
                        SOCK_SENDBUF_LOCK_ASSERT(so);
        } else {
                if (SOLISTENING(so))
                        SOLISTEN_UNLOCK_ASSERT(so);
                else
                        SOCK_SENDBUF_UNLOCK_ASSERT(so);
        }
}

/*
 * Create an external-format (``xsocket'') structure using the information in
 * the kernel-format socket structure pointed to by so.  This is done to
 * reduce the spew of irrelevant information over this interface, to isolate
 * user code from changes in the kernel structure, and potentially to provide
 * information-hiding if we decide that some of this information should be
 * hidden from users.
 */
void
sotoxsocket(struct socket *so, struct xsocket *xso)
{

        bzero(xso, sizeof(*xso));
        xso->xso_len = sizeof *xso;
        xso->xso_so = (uintptr_t)so;
        xso->so_type = so->so_type;
        xso->so_options = so->so_options;
        xso->so_linger = so->so_linger;
        xso->so_state = so->so_state;
        xso->so_pcb = (uintptr_t)so->so_pcb;
        xso->xso_protocol = so->so_proto->pr_protocol;
        xso->xso_family = so->so_proto->pr_domain->dom_family;
        xso->so_timeo = so->so_timeo;
        xso->so_error = so->so_error;
        xso->so_uid = so->so_cred->cr_uid;
        xso->so_pgid = so->so_sigio ? so->so_sigio->sio_pgid : 0;
        SOCK_LOCK(so);
        xso->so_fibnum = so->so_fibnum;
        if (SOLISTENING(so)) {
                xso->so_qlen = so->sol_qlen;
                xso->so_incqlen = so->sol_incqlen;
                xso->so_qlimit = so->sol_qlimit;
                xso->so_oobmark = 0;
        } else {
                xso->so_state |= so->so_qstate;
                xso->so_qlen = xso->so_incqlen = xso->so_qlimit = 0;
                xso->so_oobmark = so->so_oobmark;
                sbtoxsockbuf(&so->so_snd, &xso->so_snd);
                sbtoxsockbuf(&so->so_rcv, &xso->so_rcv);
                if ((so->so_rcv.sb_flags & SB_SPLICED) != 0)
                        xso->so_splice_so = (uintptr_t)so->so_splice->dst;
        }
        SOCK_UNLOCK(so);
}

int
so_options_get(const struct socket *so)
{

        return (so->so_options);
}

void
so_options_set(struct socket *so, int val)
{

        so->so_options = val;
}

int
so_error_get(const struct socket *so)
{

        return (so->so_error);
}

void
so_error_set(struct socket *so, int val)
{

        so->so_error = val;
}