xref: /xnu-11215.41.3/bsd/kern/uipc_socket2.c (revision 33de042d024d46de5ff4e89f2471de6608e37fa4)

/*
 * Copyright (c) 1998-2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1988, 1990, 1993
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)uipc_socket2.c	8.1 (Berkeley) 6/10/93
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mcache.h>
#include <sys/protosw.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/unpcb.h>
#include <sys/ev.h>
#include <kern/locks.h>
#include <net/route.h>
#include <net/content_filter.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp_var.h>
#include <sys/kdebug.h>
#include <libkern/OSAtomic.h>
#include <net/droptap.h>

#if CONFIG_MACF
#include <security/mac_framework.h>
#endif

#include <mach/vm_param.h>

#if MPTCP
#include <netinet/mptcp_var.h>
#endif

#include <net/sockaddr_utils.h>

extern uint32_t net_wake_pkt_debug;

#define DBG_FNC_SBDROP          NETDBG_CODE(DBG_NETSOCK, 4)
#define DBG_FNC_SBAPPEND        NETDBG_CODE(DBG_NETSOCK, 5)

SYSCTL_DECL(_kern_ipc);

__private_extern__ u_int32_t net_io_policy_throttle_best_effort = 0;
SYSCTL_INT(_kern_ipc, OID_AUTO, throttle_best_effort,
    CTLFLAG_RW | CTLFLAG_LOCKED, &net_io_policy_throttle_best_effort, 0, "");

static inline void sbcompress(struct sockbuf *, struct mbuf *, struct mbuf *);
static struct socket *sonewconn_internal(struct socket *, int);
static int sbappendcontrol_internal(struct sockbuf *, struct mbuf *,
    struct mbuf *);
static void soevent_ifdenied(struct socket *);

static int sbappendrecord_common(struct sockbuf *sb, struct mbuf *m0, boolean_t nodrop);
static int sbappend_common(struct sockbuf *sb, struct mbuf *m, boolean_t nodrop);

/*
 * Primitive routines for operating on sockets and socket buffers
 */
static int soqlimitcompat = 1;
static int soqlencomp = 0;

/*
 * Based on the number of mbuf clusters configured, high_sb_max and sb_max can
 * get scaled up or down to suit that memory configuration. high_sb_max is a
 * higher limit on sb_max that is checked when sb_max gets set through sysctl.
 */
uint32_t       sb_max = SB_MAX;
uint32_t       high_sb_max = SB_MAX;

static uint32_t sb_efficiency = 8;    /* parameter for sbreserve() */

uint32_t net_io_policy_log = 0;        /* log socket policy changes */
#if CONFIG_PROC_UUID_POLICY
uint32_t net_io_policy_uuid = 1;       /* enable UUID socket policy */
#endif /* CONFIG_PROC_UUID_POLICY */

/*
 * 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)
{
	so->so_state &= ~(SS_ISCONNECTED | SS_ISDISCONNECTING);
	so->so_state |= SS_ISCONNECTING;

	sflt_notify(so, sock_evt_connecting, NULL);
}

void
soisconnected(struct socket *so)
{
	/*
	 * If socket is subject to filter and is pending initial verdict,
	 * delay marking socket as connected and do not present the connected
	 * socket to user just yet.
	 */
	if (cfil_sock_connected_pending_verdict(so)) {
		return;
	}

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

	soreserve_preconnect(so, 0);

	sflt_notify(so, sock_evt_connected, NULL);

	if (so->so_head != NULL && (so->so_state & SS_INCOMP)) {
		struct socket *head = so->so_head;
		int locked = 0;

		/*
		 * Enforce lock order when the protocol has per socket locks
		 */
		if (head->so_proto->pr_getlock != NULL) {
			socket_lock(head, 1);
			so_acquire_accept_list(head, so);
			locked = 1;
		}
		if (so->so_head == head && (so->so_state & SS_INCOMP)) {
			so->so_state &= ~SS_INCOMP;
			so->so_state |= SS_COMP;
			TAILQ_REMOVE(&head->so_incomp, so, so_list);
			TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
			head->so_incqlen--;

			/*
			 * We have to release the accept list in
			 * case a socket callback calls sock_accept()
			 */
			if (locked != 0) {
				so_release_accept_list(head);
				socket_unlock(so, 0);
			}
			sorwakeup(head);
			wakeup_one((caddr_t)&head->so_timeo);

			if (locked != 0) {
				socket_unlock(head, 1);
				socket_lock(so, 0);
			}
		} else if (locked != 0) {
			so_release_accept_list(head);
			socket_unlock(head, 1);
		}
	} else {
		wakeup((caddr_t)&so->so_timeo);
		sorwakeup(so);
		sowwakeup(so);
		soevent(so, SO_FILT_HINT_LOCKED | SO_FILT_HINT_CONNECTED |
		    SO_FILT_HINT_CONNINFO_UPDATED);
	}
}

boolean_t
socanwrite(struct socket *so)
{
	return (so->so_state & SS_ISCONNECTED) ||
	       !(so->so_proto->pr_flags & PR_CONNREQUIRED) ||
	       (so->so_flags1 & SOF1_PRECONNECT_DATA);
}

void
soisdisconnecting(struct socket *so)
{
	so->so_state &= ~SS_ISCONNECTING;
	so->so_state |= (SS_ISDISCONNECTING | SS_CANTRCVMORE | SS_CANTSENDMORE);
	soevent(so, SO_FILT_HINT_LOCKED);
	sflt_notify(so, sock_evt_disconnecting, NULL);
	wakeup((caddr_t)&so->so_timeo);
	sowwakeup(so);
	sorwakeup(so);
}

void
soisdisconnected(struct socket *so)
{
	so->so_state &= ~(SS_ISCONNECTING | SS_ISCONNECTED | SS_ISDISCONNECTING);
	so->so_state |= (SS_CANTRCVMORE | SS_CANTSENDMORE | SS_ISDISCONNECTED);
	soevent(so, SO_FILT_HINT_LOCKED | SO_FILT_HINT_DISCONNECTED |
	    SO_FILT_HINT_CONNINFO_UPDATED);
	sflt_notify(so, sock_evt_disconnected, NULL);
	wakeup((caddr_t)&so->so_timeo);
	sowwakeup(so);
	sorwakeup(so);

#if CONTENT_FILTER
	/* Notify content filters as soon as we cannot send/receive data */
	cfil_sock_notify_shutdown(so, SHUT_RDWR);
#endif /* CONTENT_FILTER */
}

/*
 * This function will issue a wakeup like soisdisconnected but it will not
 * notify the socket filters. This will avoid unlocking the socket
 * in the midst of closing it.
 */
void
sodisconnectwakeup(struct socket *so)
{
	so->so_state &= ~(SS_ISCONNECTING | SS_ISCONNECTED | SS_ISDISCONNECTING);
	so->so_state |= (SS_CANTRCVMORE | SS_CANTSENDMORE | SS_ISDISCONNECTED);
	soevent(so, SO_FILT_HINT_LOCKED | SO_FILT_HINT_DISCONNECTED |
	    SO_FILT_HINT_CONNINFO_UPDATED);
	wakeup((caddr_t)&so->so_timeo);
	sowwakeup(so);
	sorwakeup(so);

#if CONTENT_FILTER
	/* Notify content filters as soon as we cannot send/receive data */
	cfil_sock_notify_shutdown(so, SHUT_RDWR);
#endif /* CONTENT_FILTER */
}

/*
 * When an attempt at a new connection is noted on a socket
 * which accepts connections, sonewconn is called.  If the
 * connection is possible (subject to space constraints, etc.)
 * then we allocate a new structure, propoerly linked into the
 * data structure of the original socket, and return this.
 * Connstatus may be 0, or SO_ISCONFIRMING, or SO_ISCONNECTED.
 */
static struct socket *
sonewconn_internal(struct socket *head, int connstatus)
{
	int so_qlen, error = 0;
	struct socket *so;
	lck_mtx_t *mutex_held;

	if (head->so_proto->pr_getlock != NULL) {
		mutex_held = (*head->so_proto->pr_getlock)(head, 0);
	} else {
		mutex_held = head->so_proto->pr_domain->dom_mtx;
	}
	LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);

	if (!soqlencomp) {
		/*
		 * This is the default case; so_qlen represents the
		 * sum of both incomplete and completed queues.
		 */
		so_qlen = head->so_qlen;
	} else {
		/*
		 * When kern.ipc.soqlencomp is set to 1, so_qlen
		 * represents only the completed queue.  Since we
		 * cannot let the incomplete queue goes unbounded
		 * (in case of SYN flood), we cap the incomplete
		 * queue length to at most somaxconn, and use that
		 * as so_qlen so that we fail immediately below.
		 */
		so_qlen = head->so_qlen - head->so_incqlen;
		if (head->so_incqlen > somaxconn) {
			so_qlen = somaxconn;
		}
	}

	if (so_qlen >=
	    (soqlimitcompat ? head->so_qlimit : (3 * head->so_qlimit / 2))) {
		return (struct socket *)0;
	}
	so = soalloc(1, SOCK_DOM(head), head->so_type);
	if (so == NULL) {
		return (struct socket *)0;
	}
	/* check if head was closed during the soalloc */
	if (head->so_proto == NULL) {
		sodealloc(so);
		return (struct socket *)0;
	}

	so->so_type = head->so_type;
	so->so_family = head->so_family;
	so->so_protocol = head->so_protocol;
	so->so_options = head->so_options & ~SO_ACCEPTCONN;
	so->so_linger = head->so_linger;
	so->so_state = head->so_state | SS_NOFDREF;
	so->so_proto = head->so_proto;
	so->so_timeo = head->so_timeo;
	so->so_pgid  = head->so_pgid;
	kauth_cred_ref(head->so_cred);
	so->so_cred = head->so_cred;
	so->so_persona_id = head->so_persona_id;
	so->last_pid = head->last_pid;
	so->last_upid = head->last_upid;
	memcpy(so->last_uuid, head->last_uuid, sizeof(so->last_uuid));
	if (head->so_flags & SOF_DELEGATED) {
		so->e_pid = head->e_pid;
		so->e_upid = head->e_upid;
		memcpy(so->e_uuid, head->e_uuid, sizeof(so->e_uuid));
	}
	/* inherit socket options stored in so_flags */
	so->so_flags = head->so_flags &
	    (SOF_NOSIGPIPE | SOF_NOADDRAVAIL | SOF_REUSESHAREUID |
	    SOF_NOTIFYCONFLICT | SOF_BINDRANDOMPORT | SOF_NPX_SETOPTSHUT |
	    SOF_NODEFUNCT | SOF_PRIVILEGED_TRAFFIC_CLASS | SOF_NOTSENT_LOWAT |
	    SOF_DELEGATED);
	so->so_flags1 |= SOF1_INBOUND;
	so->so_usecount = 1;
	so->next_lock_lr = 0;
	so->next_unlock_lr = 0;

	so->so_rcv.sb_flags |= SB_RECV; /* XXX */
	so->so_rcv.sb_so = so->so_snd.sb_so = so;

	/* inherit traffic management properties of listener */
	so->so_flags1 |=
	    head->so_flags1 & (SOF1_TRAFFIC_MGT_SO_BACKGROUND | SOF1_TC_NET_SERV_TYPE |
	    SOF1_QOSMARKING_ALLOWED | SOF1_QOSMARKING_POLICY_OVERRIDE);
	so->so_background_thread = head->so_background_thread;
	so->so_traffic_class = head->so_traffic_class;
	so->so_netsvctype = head->so_netsvctype;

	if (soreserve(so, head->so_snd.sb_hiwat, head->so_rcv.sb_hiwat)) {
		sodealloc(so);
		return (struct socket *)0;
	}
	so->so_rcv.sb_flags |= (head->so_rcv.sb_flags & SB_USRSIZE);
	so->so_snd.sb_flags |= (head->so_snd.sb_flags & SB_USRSIZE);

	/*
	 * Must be done with head unlocked to avoid deadlock
	 * for protocol with per socket mutexes.
	 */
	if (head->so_proto->pr_unlock) {
		socket_unlock(head, 0);
	}
	if (((*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL) != 0) ||
	    error) {
		sodealloc(so);
		if (head->so_proto->pr_unlock) {
			socket_lock(head, 0);
		}
		return (struct socket *)0;
	}
	if (head->so_proto->pr_unlock) {
		socket_lock(head, 0);
		/*
		 * Radar 7385998 Recheck that the head is still accepting
		 * to avoid race condition when head is getting closed.
		 */
		if ((head->so_options & SO_ACCEPTCONN) == 0) {
			so->so_state &= ~SS_NOFDREF;
			soclose(so);
			return (struct socket *)0;
		}
	}

	if (so->so_proto->pr_copy_last_owner != NULL) {
		(*so->so_proto->pr_copy_last_owner)(so, head);
	}
	os_atomic_inc(&so->so_proto->pr_domain->dom_refs, relaxed);

	/* Insert in head appropriate lists */
	so_acquire_accept_list(head, NULL);

	so->so_head = head;

	/*
	 * Since this socket is going to be inserted into the incomp
	 * queue, it can be picked up by another thread in
	 * tcp_dropdropablreq to get dropped before it is setup..
	 * To prevent this race, set in-progress flag which can be
	 * cleared later
	 */
	so->so_flags |= SOF_INCOMP_INPROGRESS;

	if (connstatus) {
		TAILQ_INSERT_TAIL(&head->so_comp, so, so_list);
		so->so_state |= SS_COMP;
	} else {
		TAILQ_INSERT_TAIL(&head->so_incomp, so, so_list);
		so->so_state |= SS_INCOMP;
		head->so_incqlen++;
	}
	head->so_qlen++;

	so_release_accept_list(head);

	/* Attach socket filters for this protocol */
	sflt_initsock(so);

	if (connstatus) {
		so->so_state |= (short)connstatus;
		sorwakeup(head);
		wakeup((caddr_t)&head->so_timeo);
	}
	return so;
}


struct socket *
sonewconn(struct socket *head, int connstatus, const struct sockaddr *from)
{
	int error = sflt_connectin(head, from);
	if (error) {
		return NULL;
	}

	return sonewconn_internal(head, connstatus);
}

/*
 * Socantsendmore indicates that no more data will be sent on the
 * socket; it would normally be applied to a socket when the user
 * informs the system that no more data is to be sent, by the protocol
 * code (in case PRU_SHUTDOWN).  Socantrcvmore indicates that no more data
 * will be received, and will normally be applied to the socket by a
 * protocol when it detects that the peer will send no more data.
 * Data queued for reading in the socket may yet be read.
 */

void
socantsendmore(struct socket *so)
{
	so->so_state |= SS_CANTSENDMORE;
	soevent(so, SO_FILT_HINT_LOCKED | SO_FILT_HINT_CANTSENDMORE);
	sflt_notify(so, sock_evt_cantsendmore, NULL);
	sowwakeup(so);
}

void
socantrcvmore(struct socket *so)
{
	so->so_state |= SS_CANTRCVMORE;
	soevent(so, SO_FILT_HINT_LOCKED | SO_FILT_HINT_CANTRCVMORE);
	sflt_notify(so, sock_evt_cantrecvmore, NULL);
	sorwakeup(so);
}

/*
 * Wait for data to arrive at/drain from a socket buffer.
 */
int
sbwait(struct sockbuf *sb)
{
	boolean_t nointr = (sb->sb_flags & SB_NOINTR);
	void *__single lr_saved = __unsafe_forge_single(void *, __builtin_return_address(0));
	struct socket *so = sb->sb_so;
	lck_mtx_t *mutex_held;
	struct timespec ts;
	int error = 0;

	if (so == NULL) {
		panic("%s: null so, sb=%p sb_flags=0x%x lr=%p",
		    __func__, sb, sb->sb_flags, lr_saved);
		/* NOTREACHED */
	} else if (so->so_usecount < 1) {
		panic("%s: sb=%p sb_flags=0x%x sb_so=%p usecount=%d lr=%p "
		    "lrh= %s\n", __func__, sb, sb->sb_flags, so,
		    so->so_usecount, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	if ((so->so_state & SS_DRAINING) || (so->so_flags & SOF_DEFUNCT)) {
		error = EBADF;
		if (so->so_flags & SOF_DEFUNCT) {
			SODEFUNCTLOG("%s[%d, %s]: defunct so 0x%llu [%d,%d] "
			    "(%d)\n", __func__, proc_selfpid(),
			    proc_best_name(current_proc()),
			    so->so_gencnt,
			    SOCK_DOM(so), SOCK_TYPE(so), error);
		}
		return error;
	}

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

	LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);

	ts.tv_sec = sb->sb_timeo.tv_sec;
	ts.tv_nsec = sb->sb_timeo.tv_usec * 1000;

	sb->sb_waiters++;
	VERIFY(sb->sb_waiters != 0);

	error = msleep((caddr_t)&sb->sb_cc, mutex_held,
	    nointr ? PSOCK : PSOCK | PCATCH,
	    nointr ? "sbwait_nointr" : "sbwait", &ts);

	VERIFY(sb->sb_waiters != 0);
	sb->sb_waiters--;

	if (so->so_usecount < 1) {
		panic("%s: 2 sb=%p sb_flags=0x%x sb_so=%p usecount=%d lr=%p "
		    "lrh= %s\n", __func__, sb, sb->sb_flags, so,
		    so->so_usecount, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	if ((so->so_state & SS_DRAINING) || (so->so_flags & SOF_DEFUNCT)) {
		error = EBADF;
		if (so->so_flags & SOF_DEFUNCT) {
			SODEFUNCTLOG("%s[%d, %s]: defunct so 0x%llu [%d,%d] "
			    "(%d)\n", __func__, proc_selfpid(),
			    proc_best_name(current_proc()),
			    so->so_gencnt,
			    SOCK_DOM(so), SOCK_TYPE(so), error);
		}
	}

	return error;
}

void
sbwakeup(struct sockbuf *sb)
{
	if (sb->sb_waiters > 0) {
		wakeup((caddr_t)&sb->sb_cc);
	}
}

/*
 * Wakeup processes waiting on a socket buffer.
 * Do asynchronous notification via SIGIO
 * if the socket has the SS_ASYNC flag set.
 */
void
sowakeup(struct socket *so, struct sockbuf *sb, struct socket *so2)
{
	if (so->so_flags & SOF_DEFUNCT) {
		SODEFUNCTLOG("%s[%d, %s]: defunct so 0x%llu [%d,%d] si 0x%x, "
		    "fl 0x%x [%s]\n", __func__, proc_selfpid(),
		    proc_best_name(current_proc()),
		    so->so_gencnt, SOCK_DOM(so),
		    SOCK_TYPE(so), (uint32_t)sb->sb_sel.si_flags, sb->sb_flags,
		    (sb->sb_flags & SB_RECV) ? "rcv" : "snd");
	}

	sb->sb_flags &= ~SB_SEL;
	selwakeup(&sb->sb_sel);
	sbwakeup(sb);
	if (so->so_state & SS_ASYNC) {
		if (so->so_pgid < 0) {
			gsignal(-so->so_pgid, SIGIO);
		} else if (so->so_pgid > 0) {
			proc_signal(so->so_pgid, SIGIO);
		}
	}
	if (sb->sb_flags & SB_KNOTE) {
		KNOTE(&sb->sb_sel.si_note, SO_FILT_HINT_LOCKED);
	}
	if (sb->sb_flags & SB_UPCALL) {
		void (*sb_upcall)(struct socket *, void *, int);
		caddr_t __single sb_upcallarg;
		int lock = !(sb->sb_flags & SB_UPCALL_LOCK);

		sb_upcall = sb->sb_upcall;
		sb_upcallarg = sb->sb_upcallarg;
		/* Let close know that we're about to do an upcall */
		so->so_upcallusecount++;

		if (lock) {
			if (so2) {
				struct unpcb *unp = sotounpcb(so2);
				unp->unp_flags |= UNP_DONTDISCONNECT;
				unp->rw_thrcount++;

				socket_unlock(so2, 0);
			}
			socket_unlock(so, 0);
		}
		(*sb_upcall)(so, sb_upcallarg, M_DONTWAIT);
		if (lock) {
			if (so2 && so > so2) {
				struct unpcb *unp;
				socket_lock(so2, 0);

				unp = sotounpcb(so2);
				unp->rw_thrcount--;
				if (unp->rw_thrcount == 0) {
					unp->unp_flags &= ~UNP_DONTDISCONNECT;
					wakeup(unp);
				}
			}

			socket_lock(so, 0);

			if (so2 && so < so2) {
				struct unpcb *unp;
				socket_lock(so2, 0);

				unp = sotounpcb(so2);
				unp->rw_thrcount--;
				if (unp->rw_thrcount == 0) {
					unp->unp_flags &= ~UNP_DONTDISCONNECT;
					wakeup(unp);
				}
			}
		}

		so->so_upcallusecount--;
		/* Tell close that it's safe to proceed */
		if ((so->so_flags & SOF_CLOSEWAIT) &&
		    so->so_upcallusecount == 0) {
			wakeup((caddr_t)&so->so_upcallusecount);
		}
	}
#if CONTENT_FILTER
	/*
	 * Trap disconnection events for content filters
	 */
	if ((so->so_flags & SOF_CONTENT_FILTER) != 0) {
		if ((sb->sb_flags & SB_RECV)) {
			if (so->so_state & (SS_CANTRCVMORE)) {
				cfil_sock_notify_shutdown(so, SHUT_RD);
			}
		} else {
			if (so->so_state & (SS_CANTSENDMORE)) {
				cfil_sock_notify_shutdown(so, SHUT_WR);
			}
		}
	}
#endif /* CONTENT_FILTER */
}

/*
 * Socket buffer (struct sockbuf) utility routines.
 *
 * Each socket contains two socket buffers: one for sending data and
 * one for receiving data.  Each buffer contains a queue of mbufs,
 * information about the number of mbufs and amount of data in the
 * queue, and other fields allowing select() statements and notification
 * on data availability to be implemented.
 *
 * Data stored in a socket buffer is maintained as a list of records.
 * Each record is a list of mbufs chained together with the m_next
 * field.  Records are chained together with the m_nextpkt field. The upper
 * level routine soreceive() expects the following conventions to be
 * observed when placing information in the receive buffer:
 *
 * 1. If the protocol requires each message be preceded by the sender's
 *    name, then a record containing that name must be present before
 *    any associated data (mbuf's must be of type MT_SONAME).
 * 2. If the protocol supports the exchange of ``access rights'' (really
 *    just additional data associated with the message), and there are
 *    ``rights'' to be received, then a record containing this data
 *    should be present (mbuf's must be of type MT_RIGHTS).
 * 3. If a name or rights record exists, then it must be followed by
 *    a data record, perhaps of zero length.
 *
 * Before using a new socket structure it is first necessary to reserve
 * buffer space to the socket, by calling sbreserve().  This should commit
 * some of the available buffer space in the system buffer pool for the
 * socket (currently, it does nothing but enforce limits).  The space
 * should be released by calling sbrelease() when the socket is destroyed.
 */

/*
 * Returns:	0			Success
 *		ENOBUFS
 */
int
soreserve(struct socket *so, uint32_t sndcc, uint32_t rcvcc)
{
	if (sbreserve(&so->so_snd, sndcc) == 0) {
		goto bad;
	} else {
		so->so_snd.sb_idealsize = sndcc;
	}

	if (sbreserve(&so->so_rcv, rcvcc) == 0) {
		goto bad2;
	} else {
		so->so_rcv.sb_idealsize = rcvcc;
	}

	if (so->so_rcv.sb_lowat == 0) {
		so->so_rcv.sb_lowat = 1;
	}
	if (so->so_snd.sb_lowat == 0) {
		so->so_snd.sb_lowat = MCLBYTES;
	}
	if (so->so_snd.sb_lowat > so->so_snd.sb_hiwat) {
		so->so_snd.sb_lowat = so->so_snd.sb_hiwat;
	}
	return 0;
bad2:
	so->so_snd.sb_flags &= ~SB_SEL;
	selthreadclear(&so->so_snd.sb_sel);
	sbrelease(&so->so_snd);
bad:
	return ENOBUFS;
}

void
soreserve_preconnect(struct socket *so, unsigned int pre_cc)
{
	/* As of now, same bytes for both preconnect read and write */
	so->so_snd.sb_preconn_hiwat = pre_cc;
	so->so_rcv.sb_preconn_hiwat = pre_cc;
}

/*
 * Allot mbufs to a sockbuf.
 * Attempt to scale mbmax so that mbcnt doesn't become limiting
 * if buffering efficiency is near the normal case.
 */
int
sbreserve(struct sockbuf *sb, uint32_t cc)
{
	if (cc > sb_max) {
		/* We would not end up changing sb_cc, so return 0 */
		if (sb->sb_hiwat == sb_max) {
			return 0;
		}
		cc = sb_max;
	}
	if (cc > sb->sb_hiwat && (sb->sb_flags & SB_LIMITED)) {
		return 0;
	}
	sb->sb_hiwat = cc;
	sb->sb_mbmax = cc * sb_efficiency;
	if (sb->sb_lowat > sb->sb_hiwat) {
		sb->sb_lowat = sb->sb_hiwat;
	}
	return 1;
}

/*
 * Free mbufs held by a socket, and reserved mbuf space.
 */
/*  WARNING needs to do selthreadclear() before calling this */
void
sbrelease(struct sockbuf *sb)
{
	sbflush(sb);
	sb->sb_hiwat = 0;
	sb->sb_mbmax = 0;
}

void
so_update_tx_data_stats(struct socket *so, uint32_t num_pkts, uint32_t space)
{
	so->so_tc_stats[SO_STATS_DATA].txpackets += num_pkts;
	so->so_tc_stats[SO_STATS_DATA].txbytes += space;
}

static void
sb_update_data_stats(struct sockbuf *sb, uint32_t space)
{
	if (sb->sb_flags & SB_RECV) {
		sb->sb_so->so_tc_stats[SO_STATS_DATA].rxpackets += 1;
		sb->sb_so->so_tc_stats[SO_STATS_DATA].rxbytes += space;
	} else {
		sb->sb_so->so_tc_stats[SO_STATS_DATA].txpackets += 1;
		sb->sb_so->so_tc_stats[SO_STATS_DATA].txbytes += space;
	}
}

static void
sb_update_no_space_stats(struct sockbuf *sb, uint32_t space)
{
	if (sb->sb_flags & SB_RECV) {
		sb->sb_so->so_tc_stats[SO_STATS_SBNOSPACE].rxpackets += 1;
		sb->sb_so->so_tc_stats[SO_STATS_SBNOSPACE].rxbytes += space;
	} else {
		sb->sb_so->so_tc_stats[SO_STATS_SBNOSPACE].txpackets += 1;
		sb->sb_so->so_tc_stats[SO_STATS_SBNOSPACE].txbytes += space;
	}
}

/*
 * Routines to add and remove
 * data from an mbuf queue.
 *
 * The routines sbappend() or sbappendrecord() are normally called to
 * append new mbufs to a socket buffer, after checking that adequate
 * space is available, comparing the function sbspace() with the amount
 * of data to be added.  sbappendrecord() differs from sbappend() in
 * that data supplied is treated as the beginning of a new record.
 * To place a sender's address, optional access rights, and data in a
 * socket receive buffer, sbappendaddr() should be used.  To place
 * access rights and data in a socket receive buffer, sbappendrights()
 * should be used.  In either case, the new data begins a new record.
 * Note that unlike sbappend() and sbappendrecord(), these routines check
 * for the caller that there will be enough space to store the data.
 * Each fails if there is not enough space, or if it cannot find mbufs
 * to store additional information in.
 *
 * Reliable protocols may use the socket send buffer to hold data
 * awaiting acknowledgement.  Data is normally copied from a socket
 * send buffer in a protocol with m_copy for output to a peer,
 * and then removing the data from the socket buffer with sbdrop()
 * or sbdroprecord() when the data is acknowledged by the peer.
 */

/*
 * Append mbuf chain m to the last record in the
 * socket buffer sb.  The additional space associated
 * the mbuf chain is recorded in sb.  Empty mbufs are
 * discarded and mbufs are compacted where possible.
 */
static int
sbappend_common(struct sockbuf *sb, struct mbuf *m, boolean_t nodrop)
{
	struct socket *__single so = sb->sb_so;
	struct soflow_hash_entry *__single dgram_flow_entry = NULL;

	if (m == NULL || (sb->sb_flags & SB_DROP)) {
		if (m != NULL && !nodrop) {
			m_freem(m);
		}
		return 0;
	}

	SBLASTRECORDCHK(sb, "sbappend 1");

	if (sb->sb_lastrecord != NULL && (sb->sb_mbtail->m_flags & M_EOR)) {
		return sbappendrecord_common(sb, m, nodrop);
	}

	if (SOCK_DOM(sb->sb_so) == PF_INET || SOCK_DOM(sb->sb_so) == PF_INET6) {
		ASSERT(nodrop == FALSE);

		if (NEED_DGRAM_FLOW_TRACKING(so)) {
			dgram_flow_entry = soflow_get_flow(so, NULL, NULL, NULL,
			    m != NULL ? m_length(m) : 0, false,
			    (m != NULL && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0);
		}

		if (sb->sb_flags & SB_RECV && !(m && m->m_flags & M_SKIPCFIL)) {
			int error = sflt_data_in(so, NULL, &m, NULL, 0);
			SBLASTRECORDCHK(sb, "sbappend 2");

#if CONTENT_FILTER
			if (error == 0) {
				error = cfil_sock_data_in(so, NULL, m, NULL, 0, dgram_flow_entry);
			}
#endif /* CONTENT_FILTER */

			if (error != 0) {
				if (error != EJUSTRETURN) {
					m_freem(m);
				}
				if (dgram_flow_entry != NULL) {
					soflow_free_flow(dgram_flow_entry);
				}
				return 0;
			}
		} else if (m) {
			m->m_flags &= ~M_SKIPCFIL;
		}

		if (dgram_flow_entry != NULL) {
			soflow_free_flow(dgram_flow_entry);
		}
	}

	/* If this is the first record, it's also the last record */
	if (sb->sb_lastrecord == NULL) {
		sb->sb_lastrecord = m;
	}

	sbcompress(sb, m, sb->sb_mbtail);
	SBLASTRECORDCHK(sb, "sbappend 3");
	return 1;
}

int
sbappend(struct sockbuf *sb, struct mbuf *m)
{
	return sbappend_common(sb, m, FALSE);
}

int
sbappend_nodrop(struct sockbuf *sb, struct mbuf *m)
{
	return sbappend_common(sb, m, TRUE);
}

/*
 * Similar to sbappend, except that this is optimized for stream sockets.
 */
int
sbappendstream(struct sockbuf *sb, struct mbuf *m)
{
	struct soflow_hash_entry *__single dgram_flow_entry = NULL;
	struct socket *__single so = sb->sb_so;

	if (m == NULL || (sb->sb_flags & SB_DROP)) {
		if (m != NULL) {
			m_freem(m);
		}
		return 0;
	}

	if (m->m_nextpkt != NULL || (sb->sb_mb != sb->sb_lastrecord)) {
		panic("sbappendstream: nexpkt %p || mb %p != lastrecord %p",
		    m->m_nextpkt, sb->sb_mb, sb->sb_lastrecord);
		/* NOTREACHED */
	}

	SBLASTMBUFCHK(sb, __func__);

	if (SOCK_DOM(sb->sb_so) == PF_INET || SOCK_DOM(sb->sb_so) == PF_INET6) {
		if (NEED_DGRAM_FLOW_TRACKING(so)) {
			dgram_flow_entry = soflow_get_flow(so, NULL, NULL, NULL,
			    m != NULL ? m_length(m) : 0, false,
			    (m != NULL && m->m_pkthdr.rcvif) ? m->m_pkthdr.rcvif->if_index : 0);
		}

		if (sb->sb_flags & SB_RECV && !(m && m->m_flags & M_SKIPCFIL)) {
			int error = sflt_data_in(so, NULL, &m, NULL, 0);
			SBLASTRECORDCHK(sb, "sbappendstream 1");

#if CONTENT_FILTER
			if (error == 0) {
				error = cfil_sock_data_in(so, NULL, m, NULL, 0, dgram_flow_entry);
			}
#endif /* CONTENT_FILTER */

			if (error != 0) {
				if (error != EJUSTRETURN) {
					m_freem(m);
				}
				if (dgram_flow_entry != NULL) {
					soflow_free_flow(dgram_flow_entry);
				}
				return 0;
			}
		} else if (m) {
			m->m_flags &= ~M_SKIPCFIL;
		}

		if (dgram_flow_entry != NULL) {
			soflow_free_flow(dgram_flow_entry);
		}
	}

	sbcompress(sb, m, sb->sb_mbtail);
	sb->sb_lastrecord = sb->sb_mb;
	SBLASTRECORDCHK(sb, "sbappendstream 2");
	return 1;
}

#ifdef SOCKBUF_DEBUG
void
sbcheck(struct sockbuf *sb)
{
	struct mbuf *m;
	struct mbuf *n = 0;
	u_int32_t len = 0, mbcnt = 0;
	lck_mtx_t *mutex_held;

	if (sb->sb_so->so_proto->pr_getlock != NULL) {
		mutex_held = (*sb->sb_so->so_proto->pr_getlock)(sb->sb_so, 0);
	} else {
		mutex_held = sb->sb_so->so_proto->pr_domain->dom_mtx;
	}

	LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);

	if (sbchecking == 0) {
		return;
	}

	for (m = sb->sb_mb; m; m = n) {
		n = m->m_nextpkt;
		for (; m; m = m->m_next) {
			len += m->m_len;
			mbcnt += _MSIZE;
			/* XXX pretty sure this is bogus */
			if (m->m_flags & M_EXT) {
				mbcnt += m->m_ext.ext_size;
			}
		}
	}
	if (len != sb->sb_cc || mbcnt != sb->sb_mbcnt) {
		panic("cc %ld != %ld || mbcnt %ld != %ld", len, sb->sb_cc,
		    mbcnt, sb->sb_mbcnt);
	}
}
#endif

void
sblastrecordchk(struct sockbuf *sb, const char *where)
{
	struct mbuf *m = sb->sb_mb;

	while (m && m->m_nextpkt) {
		m = m->m_nextpkt;
	}

	if (m != sb->sb_lastrecord) {
		printf("sblastrecordchk: mb 0x%llx lastrecord 0x%llx "
		    "last 0x%llx\n",
		    (uint64_t)VM_KERNEL_ADDRPERM(sb->sb_mb),
		    (uint64_t)VM_KERNEL_ADDRPERM(sb->sb_lastrecord),
		    (uint64_t)VM_KERNEL_ADDRPERM(m));
		printf("packet chain:\n");
		for (m = sb->sb_mb; m != NULL; m = m->m_nextpkt) {
			printf("\t0x%llx\n", (uint64_t)VM_KERNEL_ADDRPERM(m));
		}
		panic("sblastrecordchk from %s", where);
	}
}

void
sblastmbufchk(struct sockbuf *sb, const char *where)
{
	struct mbuf *m = sb->sb_mb;
	struct mbuf *n;

	while (m && m->m_nextpkt) {
		m = m->m_nextpkt;
	}

	while (m && m->m_next) {
		m = m->m_next;
	}

	if (m != sb->sb_mbtail) {
		printf("sblastmbufchk: mb 0x%llx mbtail 0x%llx last 0x%llx\n",
		    (uint64_t)VM_KERNEL_ADDRPERM(sb->sb_mb),
		    (uint64_t)VM_KERNEL_ADDRPERM(sb->sb_mbtail),
		    (uint64_t)VM_KERNEL_ADDRPERM(m));
		printf("packet tree:\n");
		for (m = sb->sb_mb; m != NULL; m = m->m_nextpkt) {
			printf("\t");
			for (n = m; n != NULL; n = n->m_next) {
				printf("0x%llx ",
				    (uint64_t)VM_KERNEL_ADDRPERM(n));
			}
			printf("\n");
		}
		panic("sblastmbufchk from %s", where);
	}
}

/*
 * Similar to sbappend, except the mbuf chain begins a new record.
 */
static int
sbappendrecord_common(struct sockbuf *sb, struct mbuf *m0, boolean_t nodrop)
{
	struct soflow_hash_entry *__single dgram_flow_entry = NULL;
	struct socket *__single so = sb->sb_so;
	struct mbuf *m;
	int space = 0;

	if (m0 == NULL || (sb->sb_flags & SB_DROP)) {
		if (m0 != NULL && nodrop == FALSE) {
			m_freem(m0);
		}
		return 0;
	}

	for (m = m0; m != NULL; m = m->m_next) {
		space += m->m_len;
	}

	if (space > sbspace(sb) && !(sb->sb_flags & SB_UNIX)) {
		sb_update_no_space_stats(sb, space);

		if (nodrop == FALSE) {
			m_freem(m0);
		}
		return 0;
	}

	if (SOCK_DOM(sb->sb_so) == PF_INET || SOCK_DOM(sb->sb_so) == PF_INET6) {
		ASSERT(nodrop == FALSE);

		if (NEED_DGRAM_FLOW_TRACKING(so)) {
			dgram_flow_entry = soflow_get_flow(so, NULL, NULL, NULL,
			    m0 != NULL ? m_length(m0) : 0, false,
			    (m0 != NULL && m0->m_pkthdr.rcvif) ? m0->m_pkthdr.rcvif->if_index : 0);
		}

		if (sb->sb_flags & SB_RECV && !(m0 && m0->m_flags & M_SKIPCFIL)) {
			int error = sflt_data_in(sb->sb_so, NULL, &m0, NULL,
			    sock_data_filt_flag_record);

#if CONTENT_FILTER
			if (error == 0) {
				error = cfil_sock_data_in(sb->sb_so, NULL, m0, NULL, 0, dgram_flow_entry);
			}
#endif /* CONTENT_FILTER */

			if (error != 0) {
				SBLASTRECORDCHK(sb, "sbappendrecord 1");
				if (error != EJUSTRETURN) {
					m_freem(m0);
				}
				if (dgram_flow_entry != NULL) {
					soflow_free_flow(dgram_flow_entry);
				}
				return 0;
			}
		} else if (m0) {
			m0->m_flags &= ~M_SKIPCFIL;
		}

		if (dgram_flow_entry != NULL) {
			soflow_free_flow(dgram_flow_entry);
		}
	}

	/*
	 * Note this permits zero length records.
	 */
	sballoc(sb, m0);
	SBLASTRECORDCHK(sb, "sbappendrecord 2");
	if (sb->sb_lastrecord != NULL) {
		sb->sb_lastrecord->m_nextpkt = m0;
	} else {
		sb->sb_mb = m0;
	}
	sb->sb_lastrecord = m0;
	sb->sb_mbtail = m0;

	m = m0->m_next;
	m0->m_next = 0;
	if (m && (m0->m_flags & M_EOR)) {
		m0->m_flags &= ~M_EOR;
		m->m_flags |= M_EOR;
	}
	sbcompress(sb, m, m0);
	SBLASTRECORDCHK(sb, "sbappendrecord 3");
	return 1;
}

int
sbappendrecord(struct sockbuf *sb, struct mbuf *m0)
{
	return sbappendrecord_common(sb, m0, FALSE);
}

int
sbappendrecord_nodrop(struct sockbuf *sb, struct mbuf *m0)
{
	return sbappendrecord_common(sb, m0, TRUE);
}

/*
 * Concatenate address (optional), control (optional) and data into one
 * single mbuf chain.  If sockbuf *sb is passed in, space check will be
 * performed.
 *
 * Returns:	mbuf chain pointer if succeeded, NULL if failed
 */
struct mbuf *
sbconcat_mbufs(struct sockbuf *sb, struct sockaddr *asa, struct mbuf *m0, struct mbuf *control)
{
	struct mbuf *m = NULL, *n = NULL;
	int space = 0;

	if (m0 && (m0->m_flags & M_PKTHDR) == 0) {
		panic("sbconcat_mbufs");
	}

	if (m0) {
		space += m0->m_pkthdr.len;
	}
	for (n = control; n; n = n->m_next) {
		space += n->m_len;
		if (n->m_next == 0) {   /* keep pointer to last control buf */
			break;
		}
	}

	if (asa != NULL) {
		_CASSERT(sizeof(asa->sa_len) == sizeof(__uint8_t));
		if (MLEN <= UINT8_MAX && asa->sa_len > MLEN) {
			return NULL;
		}
		space += asa->sa_len;
	}

	if (sb != NULL && space > sbspace(sb)) {
		sb_update_no_space_stats(sb, space);

		return NULL;
	}

	if (n) {
		n->m_next = m0;         /* concatenate data to control */
	} else {
		control = m0;
	}

	if (asa != NULL) {
		MGET(m, M_DONTWAIT, MT_SONAME);
		if (m == 0) {
			if (n) {
				/* unchain control and data if necessary */
				n->m_next = NULL;
			}
			return NULL;
		}
		m->m_len = asa->sa_len;
		SOCKADDR_COPY(asa, mtod(m, caddr_t), asa->sa_len);

		m->m_next = control;
	} else {
		m = control;
	}

	return m;
}

/*
 * Queue mbuf chain to the receive queue of a socket.
 * Parameter space is the total len of the mbuf chain.
 * If passed in, sockbuf space will be checked.
 *
 * Returns:	0		Invalid mbuf chain
 *			1		Success
 */
int
sbappendchain(struct sockbuf *sb, struct mbuf *m)
{
	struct mbuf *n, *nlast;
	int space = 0;

	if (m == NULL) {
		return 0;
	}

	for (n = m; n->m_next != NULL; n = n->m_next) {
		space += n->m_len;
		sballoc(sb, n);
	}
	space += n->m_len;
	sballoc(sb, n);
	nlast = n;

	if (sb->sb_lastrecord != NULL) {
		sb->sb_lastrecord->m_nextpkt = m;
	} else {
		sb->sb_mb = m;
	}
	sb->sb_lastrecord = m;
	sb->sb_mbtail = nlast;

	sb_update_data_stats(sb, space);

	SBLASTMBUFCHK(sb, __func__);
	SBLASTRECORDCHK(sb, "sbappendadddr 2");
	return 1;
}

/*
 * Returns:	0			Error: No space/out of mbufs/etc.
 *		1			Success
 *
 * Imputed:	(*error_out)		errno for error
 *		ENOBUFS
 *	sflt_data_in:???		[whatever a filter author chooses]
 */
int
sbappendaddr(struct sockbuf *sb, struct sockaddr *asa, struct mbuf *m0,
    struct mbuf *control, int *error_out)
{
	int result = 0;
	boolean_t sb_unix = (sb->sb_flags & SB_UNIX);
	struct mbuf *mbuf_chain = NULL;
	struct soflow_hash_entry *__single dgram_flow_entry = NULL;
	struct socket *__single so = sb->sb_so;

	if (error_out) {
		*error_out = 0;
	}

	if (m0 && (m0->m_flags & M_PKTHDR) == 0) {
		panic("sbappendaddrorfree");
	}

	if (sb->sb_flags & SB_DROP) {
		if (m0 != NULL) {
			m_freem(m0);
		}
		if (control != NULL && !sb_unix) {
			m_freem(control);
		}
		if (error_out != NULL) {
			*error_out = EINVAL;
		}
		return 0;
	}

	if (SOCK_DOM(sb->sb_so) == PF_INET || SOCK_DOM(sb->sb_so) == PF_INET6) {
		/* Call socket data in filters */

		if (NEED_DGRAM_FLOW_TRACKING(so)) {
			dgram_flow_entry = soflow_get_flow(so, NULL, asa, control,
			    m0 != NULL ? m_length(m0) : 0,
			    false,
			    (m0 != NULL && m0->m_pkthdr.rcvif) ? m0->m_pkthdr.rcvif->if_index : 0);
		}

		if (sb->sb_flags & SB_RECV && !(m0 && m0->m_flags & M_SKIPCFIL)) {
			int error;
			error = sflt_data_in(sb->sb_so, asa, &m0, &control, 0);
			SBLASTRECORDCHK(sb, __func__);

#if CONTENT_FILTER
			if (error == 0) {
				error = cfil_sock_data_in(sb->sb_so, asa, m0, control,
				    0, dgram_flow_entry);
			}
#endif /* CONTENT_FILTER */

			if (error) {
				if (error != EJUSTRETURN) {
					if (m0) {
						m_freem(m0);
					}
					if (control != NULL && !sb_unix) {
						m_freem(control);
					}
					if (error_out) {
						*error_out = error;
					}
				}
				if (dgram_flow_entry != NULL) {
					soflow_free_flow(dgram_flow_entry);
				}
				return 0;
			}
		} else if (m0) {
			m0->m_flags &= ~M_SKIPCFIL;
		}

		if (dgram_flow_entry != NULL) {
			soflow_free_flow(dgram_flow_entry);
		}
	}

	mbuf_chain = sbconcat_mbufs(sb, asa, m0, control);
	SBLASTRECORDCHK(sb, "sbappendadddr 1");
	result = sbappendchain(sb, mbuf_chain);
	if (result == 0) {
		if (m0) {
			m_freem(m0);
		}
		if (control != NULL && !sb_unix) {
			m_freem(control);
		}
		if (error_out) {
			*error_out = ENOBUFS;
		}
	}

	return result;
}

inline boolean_t
is_cmsg_valid(struct mbuf *control, struct cmsghdr *cmsg)
{
	if (cmsg == NULL) {
		return FALSE;
	}

	if (cmsg->cmsg_len < sizeof(struct cmsghdr)) {
		return FALSE;
	}

	if ((uintptr_t)control->m_data >= (uintptr_t)cmsg + cmsg->cmsg_len) {
		return FALSE;
	}

	if ((uintptr_t)control->m_data + control->m_len <
	    (uintptr_t)cmsg + cmsg->cmsg_len) {
		return FALSE;
	}

	return TRUE;
}

static int
sbappendcontrol_internal(struct sockbuf *sb, struct mbuf *m0,
    struct mbuf *control)
{
	struct mbuf *m, *mlast, *n;
	int space = 0;

	if (control == 0) {
		panic("sbappendcontrol");
	}

	for (m = control;; m = m->m_next) {
		space += m->m_len;
		if (m->m_next == 0) {
			break;
		}
	}
	n = m;                  /* save pointer to last control buffer */
	for (m = m0; m; m = m->m_next) {
		space += m->m_len;
	}
	if (space > sbspace(sb) && !(sb->sb_flags & SB_UNIX)) {
		sb_update_no_space_stats(sb, space);

		return 0;
	}
	n->m_next = m0;                 /* concatenate data to control */
	SBLASTRECORDCHK(sb, "sbappendcontrol 1");

	for (m = control; m->m_next != NULL; m = m->m_next) {
		sballoc(sb, m);
	}
	sballoc(sb, m);
	mlast = m;

	if (sb->sb_lastrecord != NULL) {
		sb->sb_lastrecord->m_nextpkt = control;
	} else {
		sb->sb_mb = control;
	}
	sb->sb_lastrecord = control;
	sb->sb_mbtail = mlast;

	sb_update_data_stats(sb, space);

	SBLASTMBUFCHK(sb, __func__);
	SBLASTRECORDCHK(sb, "sbappendcontrol 2");
	return 1;
}

int
sbappendcontrol(struct sockbuf *sb, struct mbuf *m0, struct mbuf *control,
    int *error_out)
{
	struct soflow_hash_entry *__single dgram_flow_entry = NULL;
	struct socket *__single so = sb->sb_so;
	int result = 0;
	boolean_t sb_unix = (sb->sb_flags & SB_UNIX);

	if (error_out) {
		*error_out = 0;
	}

	if (sb->sb_flags & SB_DROP) {
		if (m0 != NULL) {
			m_freem(m0);
		}
		if (control != NULL && !sb_unix) {
			m_freem(control);
		}
		if (error_out != NULL) {
			*error_out = EINVAL;
		}
		return 0;
	}

	if (SOCK_DOM(sb->sb_so) == PF_INET || SOCK_DOM(sb->sb_so) == PF_INET6) {
		if (NEED_DGRAM_FLOW_TRACKING(so)) {
			dgram_flow_entry = soflow_get_flow(so, NULL, NULL, control,
			    m0 != NULL ? m_length(m0) : 0, false,
			    (m0 != NULL && m0->m_pkthdr.rcvif) ? m0->m_pkthdr.rcvif->if_index : 0);
		}

		if (sb->sb_flags & SB_RECV && !(m0 && m0->m_flags & M_SKIPCFIL)) {
			int error;

			error = sflt_data_in(sb->sb_so, NULL, &m0, &control, 0);
			SBLASTRECORDCHK(sb, __func__);

#if CONTENT_FILTER
			if (error == 0) {
				error = cfil_sock_data_in(sb->sb_so, NULL, m0, control,
				    0, dgram_flow_entry);
			}
#endif /* CONTENT_FILTER */

			if (error) {
				if (error != EJUSTRETURN) {
					if (m0) {
						m_freem(m0);
					}
					if (control != NULL && !sb_unix) {
						m_freem(control);
					}
					if (error_out) {
						*error_out = error;
					}
				}
				if (dgram_flow_entry != NULL) {
					soflow_free_flow(dgram_flow_entry);
				}
				return 0;
			}
		} else if (m0) {
			m0->m_flags &= ~M_SKIPCFIL;
		}

		if (dgram_flow_entry != NULL) {
			soflow_free_flow(dgram_flow_entry);
		}
	}

	result = sbappendcontrol_internal(sb, m0, control);
	if (result == 0) {
		if (m0) {
			m_freem(m0);
		}
		if (control != NULL && !sb_unix) {
			m_freem(control);
		}
		if (error_out) {
			*error_out = ENOBUFS;
		}
	}

	return result;
}

/*
 * TCP streams have Multipath TCP support or are regular TCP sockets.
 */
int
sbappendstream_rcvdemux(struct socket *so, struct mbuf *m)
{
	int ret = 0;

	if ((m != NULL) &&
	    m_pktlen(m) <= 0 &&
	    !((so->so_flags & SOF_MP_SUBFLOW) &&
	    (m->m_flags & M_PKTHDR) &&
	    (m->m_pkthdr.pkt_flags & PKTF_MPTCP_DFIN))) {
		m_freem(m);
		return ret;
	}

#if MPTCP
	if (so->so_flags & SOF_MP_SUBFLOW) {
		return sbappendmptcpstream_rcv(&so->so_rcv, m);
	} else
#endif /* MPTCP */
	{
		return sbappendstream(&so->so_rcv, m);
	}
}

#if MPTCP
int
sbappendmptcpstream_rcv(struct sockbuf *sb, struct mbuf *m)
{
	struct socket *so = sb->sb_so;

	VERIFY(m == NULL || (m->m_flags & M_PKTHDR));
	/* SB_NOCOMPRESS must be set prevent loss of M_PKTHDR data */
	VERIFY((sb->sb_flags & (SB_RECV | SB_NOCOMPRESS)) ==
	    (SB_RECV | SB_NOCOMPRESS));

	if (m == NULL || m_pktlen(m) == 0 || (sb->sb_flags & SB_DROP) ||
	    (so->so_state & SS_CANTRCVMORE)) {
		if (m && (m->m_flags & M_PKTHDR) &&
		    m_pktlen(m) == 0 &&
		    (m->m_pkthdr.pkt_flags & PKTF_MPTCP_DFIN)) {
			mptcp_input(tptomptp(sototcpcb(so))->mpt_mpte, m);
			return 1;
		} else if (m != NULL) {
			m_freem(m);
		}
		return 0;
	}
	/* the socket is not closed, so SOF_MP_SUBFLOW must be set */
	VERIFY(so->so_flags & SOF_MP_SUBFLOW);

	if (m->m_nextpkt != NULL || (sb->sb_mb != sb->sb_lastrecord)) {
		panic("%s: nexpkt %p || mb %p != lastrecord %p", __func__,
		    m->m_nextpkt, sb->sb_mb, sb->sb_lastrecord);
		/* NOTREACHED */
	}

	SBLASTMBUFCHK(sb, __func__);

	/* No filter support (SB_RECV) on mptcp subflow sockets */

	sbcompress(sb, m, sb->sb_mbtail);
	sb->sb_lastrecord = sb->sb_mb;
	SBLASTRECORDCHK(sb, __func__);
	return 1;
}
#endif /* MPTCP */

/*
 * Compress mbuf chain m into the socket
 * buffer sb following mbuf n.  If n
 * is null, the buffer is presumed empty.
 */
static inline void
sbcompress(struct sockbuf *sb, struct mbuf *m, struct mbuf *n)
{
	int eor = 0, compress = (!(sb->sb_flags & SB_NOCOMPRESS));
	struct mbuf *o;
	int space = 0;

	if (m == NULL) {
		/* There is nothing to compress; just update the tail */
		for (; n->m_next != NULL; n = n->m_next) {
			;
		}
		sb->sb_mbtail = n;
		goto done;
	}

	while (m != NULL) {
		space += m->m_len;
		eor |= m->m_flags & M_EOR;
		if (compress && m->m_len == 0 && (eor == 0 ||
		    (((o = m->m_next) || (o = n)) && o->m_type == m->m_type))) {
			if (sb->sb_lastrecord == m) {
				sb->sb_lastrecord = m->m_next;
			}
			m = m_free(m);
			continue;
		}
		if (compress && n != NULL && (n->m_flags & M_EOR) == 0 &&
#ifndef __APPLE__
		    M_WRITABLE(n) &&
#endif
		    m->m_len <= MCLBYTES / 4 && /* XXX: Don't copy too much */
		    m->m_len <= M_TRAILINGSPACE(n) &&
		    n->m_type == m->m_type) {
			bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len,
			    (unsigned)m->m_len);
			n->m_len += m->m_len;
			sb->sb_cc += m->m_len;
			if (!m_has_mtype(m, MTF_DATA | MTF_HEADER | MTF_OOBDATA)) {
				/* XXX: Probably don't need */
				sb->sb_ctl += m->m_len;
			}

			/* update send byte count */
			if (sb->sb_flags & SB_SNDBYTE_CNT) {
				inp_incr_sndbytes_total(sb->sb_so,
				    m->m_len);
				inp_incr_sndbytes_unsent(sb->sb_so,
				    m->m_len);
			}
			m = m_free(m);
			continue;
		}
		if (n != NULL) {
			n->m_next = m;
		} else {
			sb->sb_mb = m;
		}
		sb->sb_mbtail = m;
		sballoc(sb, m);
		n = m;
		m->m_flags &= ~M_EOR;
		m = m->m_next;
		n->m_next = NULL;
	}
	if (eor != 0) {
		if (n != NULL) {
			n->m_flags |= M_EOR;
		} else {
			printf("semi-panic: sbcompress\n");
		}
	}
	sb_update_data_stats(sb, space);
done:
	SBLASTMBUFCHK(sb, __func__);
}

void
sb_empty_assert(struct sockbuf *sb, const char *where)
{
	if (!(sb->sb_cc == 0 && sb->sb_mb == NULL && sb->sb_mbcnt == 0 &&
	    sb->sb_mbtail == NULL && sb->sb_lastrecord == NULL)) {
		panic("%s: sb %p so %p cc %d mbcnt %d mb %p mbtail %p "
		    "lastrecord %p\n", where, sb, sb->sb_so, sb->sb_cc,
		    sb->sb_mbcnt, sb->sb_mb, sb->sb_mbtail,
		    sb->sb_lastrecord);
		/* NOTREACHED */
	}
}

/*
 * Free all mbufs in a sockbuf.
 * Check that all resources are reclaimed.
 */
void
sbflush(struct sockbuf *sb)
{
	void *__single lr_saved = __unsafe_forge_single(void *, __builtin_return_address(0));
	struct socket *so = sb->sb_so;

	/* so_usecount may be 0 if we get here from sofreelastref() */
	if (so == NULL) {
		panic("%s: null so, sb=%p sb_flags=0x%x lr=%p",
		    __func__, sb, sb->sb_flags, lr_saved);
		/* NOTREACHED */
	} else if (so->so_usecount < 0) {
		panic("%s: sb=%p sb_flags=0x%x sb_so=%p usecount=%d lr=%p "
		    "lrh= %s\n", __func__, sb, sb->sb_flags, so,
		    so->so_usecount, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	/*
	 * Obtain lock on the socket buffer (SB_LOCK).  This is required
	 * to prevent the socket buffer from being unexpectedly altered
	 * while it is used by another thread in socket send/receive.
	 *
	 * sblock() must not fail here, hence the assertion.
	 */
	(void) sblock(sb, SBL_WAIT | SBL_NOINTR | SBL_IGNDEFUNCT);
	VERIFY(sb->sb_flags & SB_LOCK);

	while (sb->sb_mbcnt > 0) {
		/*
		 * Don't call sbdrop(sb, 0) if the leading mbuf is non-empty:
		 * we would loop forever. Panic instead.
		 */
		if (!sb->sb_cc && (sb->sb_mb == NULL || sb->sb_mb->m_len)) {
			break;
		}
		sbdrop(sb, (int)sb->sb_cc);
	}

	if (sb->sb_flags & SB_SENDHEAD) {
		sb->sb_sendhead = NULL;
	}

	sb_empty_assert(sb, __func__);
	sbunlock(sb, TRUE);     /* keep socket locked */
}

/*
 * Drop data from (the front of) a sockbuf.
 * use m_freem_list to free the mbuf structures
 * under a single lock... this is done by pruning
 * the top of the tree from the body by keeping track
 * of where we get to in the tree and then zeroing the
 * two pertinent pointers m_nextpkt and m_next
 * the socket buffer is then updated to point at the new
 * top of the tree and the pruned area is released via
 * m_freem_list.
 */
void
sbdrop(struct sockbuf *sb, int len)
{
	struct mbuf *m, *free_list, *ml;
	struct mbuf *next, *last;

	next = (m = sb->sb_mb) ? m->m_nextpkt : 0;
#if MPTCP
	if (m != NULL && len > 0 && !(sb->sb_flags & SB_RECV) &&
	    ((sb->sb_so->so_flags & SOF_MP_SUBFLOW) ||
	    (SOCK_CHECK_DOM(sb->sb_so, PF_MULTIPATH) &&
	    SOCK_CHECK_PROTO(sb->sb_so, IPPROTO_TCP))) &&
	    !(sb->sb_so->so_flags1 & SOF1_POST_FALLBACK_SYNC)) {
		mptcp_preproc_sbdrop(sb->sb_so, m, (unsigned int)len);
	}
	if (m != NULL && len > 0 && !(sb->sb_flags & SB_RECV) &&
	    (sb->sb_so->so_flags & SOF_MP_SUBFLOW) &&
	    (sb->sb_so->so_flags1 & SOF1_POST_FALLBACK_SYNC)) {
		mptcp_fallback_sbdrop(sb->sb_so, m, len);
	}
#endif /* MPTCP */
	KERNEL_DEBUG((DBG_FNC_SBDROP | DBG_FUNC_START), sb, len, 0, 0, 0);

	free_list = last = m;
	ml = (struct mbuf *)0;

	if (sb->sb_flags & SB_SENDHEAD) {
		sb->sb_sendoff -= MIN(len, sb->sb_sendoff);
	}

	while (len > 0) {
		if (m == NULL) {
			if (next == NULL) {
				/*
				 * temporarily replacing this panic with printf
				 * because it occurs occasionally when closing
				 * a socket when there is no harm in ignoring
				 * it. This problem will be investigated
				 * further.
				 */
				/* panic("sbdrop"); */
				printf("sbdrop - count not zero\n");
				len = 0;
				/*
				 * zero the counts. if we have no mbufs,
				 * we have no data (PR-2986815)
				 */
				sb->sb_cc = 0;
				sb->sb_mbcnt = 0;
				break;
			}
			m = last = next;
			next = m->m_nextpkt;
			continue;
		}
		if (m->m_len > len) {
			m->m_len -= len;
			m->m_data += len;
			sb->sb_cc -= len;
			/* update the send byte count */
			if (sb->sb_flags & SB_SNDBYTE_CNT) {
				inp_decr_sndbytes_total(sb->sb_so, len);
			}
			if (sb->sb_flags & SB_SENDHEAD) {
				if (sb->sb_sendhead == m) {
					sb->sb_sendhead = NULL;
				}
			}
			if (!m_has_mtype(m, MTF_DATA | MTF_HEADER | MTF_OOBDATA)) {
				sb->sb_ctl -= len;
			}
			break;
		}
		len -= m->m_len;
		sbfree(sb, m);

		ml = m;
		m = m->m_next;
	}
	while (m && m->m_len == 0) {
		sbfree(sb, m);

		ml = m;
		m = m->m_next;
	}
	if (ml) {
		ml->m_next = (struct mbuf *)0;
		last->m_nextpkt = (struct mbuf *)0;
		m_freem_list(free_list);
	}
	if (m) {
		sb->sb_mb = m;
		m->m_nextpkt = next;
	} else {
		sb->sb_mb = next;
	}

	/*
	 * First part is an inline SB_EMPTY_FIXUP().  Second part
	 * makes sure sb_lastrecord is up-to-date if we dropped
	 * part of the last record.
	 */
	m = sb->sb_mb;
	if (m == NULL) {
		sb->sb_mbtail = NULL;
		sb->sb_lastrecord = NULL;
	} else if (m->m_nextpkt == NULL) {
		sb->sb_lastrecord = m;
	}

#if CONTENT_FILTER
	cfil_sock_buf_update(sb);
#endif /* CONTENT_FILTER */

	KERNEL_DEBUG((DBG_FNC_SBDROP | DBG_FUNC_END), sb, 0, 0, 0, 0);
}

/*
 * Drop a record off the front of a sockbuf
 * and move the next record to the front.
 */
void
sbdroprecord(struct sockbuf *sb)
{
	struct mbuf *m, *mn;

	m = sb->sb_mb;
	if (m) {
		sb->sb_mb = m->m_nextpkt;
		do {
			sbfree(sb, m);
			MFREE(m, mn);
			m = mn;
		} while (m);
	}
	SB_EMPTY_FIXUP(sb);
}

/*
 * Create a "control" mbuf containing the specified data
 * with the specified type for presentation on a socket buffer.
 */
struct mbuf *
sbcreatecontrol(caddr_t __sized_by(size) p, int size, int type, int level)
{
	struct cmsghdr *cp;
	struct mbuf *m;

	if (CMSG_SPACE((u_int)size) > MLEN) {
		return (struct mbuf *)NULL;
	}
	if ((m = m_get(M_DONTWAIT, MT_CONTROL)) == NULL) {
		return (struct mbuf *)NULL;
	}
	cp = mtod(m, struct cmsghdr *);
	VERIFY(IS_P2ALIGNED(cp, sizeof(u_int32_t)));
	/* XXX check size? */
	(void) memcpy(CMSG_DATA(cp), p, size);
	m->m_len = (int32_t)CMSG_SPACE(size);
	cp->cmsg_len = CMSG_LEN(size);
	cp->cmsg_level = level;
	cp->cmsg_type = type;
	return m;
}

struct mbuf **
sbcreatecontrol_mbuf(caddr_t __sized_by(size) p, int size, int type, int level, struct mbuf **mp)
{
	struct mbuf *m;
	struct cmsghdr *cp;

	if (*mp == NULL) {
		*mp = sbcreatecontrol(p, size, type, level);
		return mp;
	}

	if (CMSG_SPACE((u_int)size) + (*mp)->m_len > MLEN) {
		mp = &(*mp)->m_next;
		*mp = sbcreatecontrol(p, size, type, level);
		return mp;
	}

	m = *mp;

	cp = (struct cmsghdr *)(void *)(mtod(m, char *) + m->m_len);
	/* CMSG_SPACE ensures 32-bit alignment */
	VERIFY(IS_P2ALIGNED(cp, sizeof(u_int32_t)));
	m->m_len += (int32_t)CMSG_SPACE(size);

	/* XXX check size? */
	(void) memcpy(CMSG_DATA(cp), p, size);
	cp->cmsg_len = CMSG_LEN(size);
	cp->cmsg_level = level;
	cp->cmsg_type = type;

	return mp;
}


/*
 * Some routines that return EOPNOTSUPP for entry points that are not
 * supported by a protocol.  Fill in as needed.
 */
int
pru_abort_notsupp(struct socket *so)
{
#pragma unused(so)
	return EOPNOTSUPP;
}

int
pru_accept_notsupp(struct socket *so, struct sockaddr **nam)
{
#pragma unused(so, nam)
	return EOPNOTSUPP;
}

int
pru_attach_notsupp(struct socket *so, int proto, struct proc *p)
{
#pragma unused(so, proto, p)
	return EOPNOTSUPP;
}

int
pru_bind_notsupp(struct socket *so, struct sockaddr *nam, struct proc *p)
{
#pragma unused(so, nam, p)
	return EOPNOTSUPP;
}

int
pru_connect_notsupp(struct socket *so, struct sockaddr *nam, struct proc *p)
{
#pragma unused(so, nam, p)
	return EOPNOTSUPP;
}

int
pru_connect2_notsupp(struct socket *so1, struct socket *so2)
{
#pragma unused(so1, so2)
	return EOPNOTSUPP;
}

int
pru_connectx_notsupp(struct socket *so, struct sockaddr *src,
    struct sockaddr *dst, struct proc *p, uint32_t ifscope,
    sae_associd_t aid, sae_connid_t *pcid, uint32_t flags, void *arg,
    uint32_t arglen, struct uio *uio, user_ssize_t *bytes_written)
{
#pragma unused(so, src, dst, p, ifscope, aid, pcid, flags, arg, arglen, uio, bytes_written)
	return EOPNOTSUPP;
}

int
pru_control_notsupp(struct socket *so,
    u_long cmd, caddr_t __sized_by(IOCPARM_LEN(cmd)) data,
    struct ifnet *ifp, struct proc *p)
{
#pragma unused(so, cmd, data, ifp, p)
	return EOPNOTSUPP;
}

int
pru_detach_notsupp(struct socket *so)
{
#pragma unused(so)
	return EOPNOTSUPP;
}

int
pru_disconnect_notsupp(struct socket *so)
{
#pragma unused(so)
	return EOPNOTSUPP;
}

int
pru_disconnectx_notsupp(struct socket *so, sae_associd_t aid, sae_connid_t cid)
{
#pragma unused(so, aid, cid)
	return EOPNOTSUPP;
}

int
pru_listen_notsupp(struct socket *so, struct proc *p)
{
#pragma unused(so, p)
	return EOPNOTSUPP;
}

int
pru_peeraddr_notsupp(struct socket *so, struct sockaddr **nam)
{
#pragma unused(so, nam)
	return EOPNOTSUPP;
}

int
pru_rcvd_notsupp(struct socket *so, int flags)
{
#pragma unused(so, flags)
	return EOPNOTSUPP;
}

int
pru_rcvoob_notsupp(struct socket *so, struct mbuf *m, int flags)
{
#pragma unused(so, m, flags)
	return EOPNOTSUPP;
}

int
pru_send_notsupp(struct socket *so, int flags, struct mbuf *m,
    struct sockaddr *addr, struct mbuf *control, struct proc *p)
{
#pragma unused(so, flags, m, addr, control, p)
	return EOPNOTSUPP;
}

int
pru_send_list_notsupp(struct socket *so, struct mbuf *m, u_int *pktcnt,
    int flags)
{
#pragma unused(so, m, pktcnt, flags)
	return EOPNOTSUPP;
}

/*
 * This isn't really a ``null'' operation, but it's the default one
 * and doesn't do anything destructive.
 */
int
pru_sense_null(struct socket *so, void *ub, int isstat64)
{
	if (isstat64 != 0) {
		struct stat64 *sb64;

		sb64 = (struct stat64 *)ub;
		sb64->st_blksize = so->so_snd.sb_hiwat;
	} else {
		struct stat *sb;

		sb = (struct stat *)ub;
		sb->st_blksize = so->so_snd.sb_hiwat;
	}

	return 0;
}

int
pru_sosend_notsupp(struct socket *so, struct sockaddr *addr, struct uio *uio,
    struct mbuf *top, struct mbuf *control, int flags)
{
#pragma unused(so, addr, uio, top, control, flags)
	return EOPNOTSUPP;
}

int
pru_sosend_list_notsupp(struct socket *so, struct mbuf *m, size_t total_len, u_int *pktcnt, int flags)
{
#pragma unused(so, m, total_len, pktcnt, flags)
	return EOPNOTSUPP;
}

int
pru_soreceive_notsupp(struct socket *so, struct sockaddr **paddr,
    struct uio *uio, struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
#pragma unused(so, paddr, uio, mp0, controlp, flagsp)
	return EOPNOTSUPP;
}

int
pru_shutdown_notsupp(struct socket *so)
{
#pragma unused(so)
	return EOPNOTSUPP;
}

int
pru_sockaddr_notsupp(struct socket *so, struct sockaddr **nam)
{
#pragma unused(so, nam)
	return EOPNOTSUPP;
}

int
pru_sopoll_notsupp(struct socket *so, int events, kauth_cred_t cred, void *wql)
{
#pragma unused(so, events, cred, wql)
	return EOPNOTSUPP;
}

int
pru_socheckopt_null(struct socket *so, struct sockopt *sopt)
{
#pragma unused(so, sopt)
	/*
	 * Allow all options for set/get by default.
	 */
	return 0;
}

static int
pru_preconnect_null(struct socket *so)
{
#pragma unused(so)
	return 0;
}

static int
pru_defunct_null(struct socket *so)
{
#pragma unused(so)
	return 0;
}


void
pru_sanitize(struct pr_usrreqs *pru)
{
#define DEFAULT(foo, bar)       if ((foo) == NULL) (foo) = (bar)
	DEFAULT(pru->pru_abort, pru_abort_notsupp);
	DEFAULT(pru->pru_accept, pru_accept_notsupp);
	DEFAULT(pru->pru_attach, pru_attach_notsupp);
	DEFAULT(pru->pru_bind, pru_bind_notsupp);
	DEFAULT(pru->pru_connect, pru_connect_notsupp);
	DEFAULT(pru->pru_connect2, pru_connect2_notsupp);
	DEFAULT(pru->pru_connectx, pru_connectx_notsupp);
	DEFAULT(pru->pru_control, pru_control_notsupp);
	DEFAULT(pru->pru_detach, pru_detach_notsupp);
	DEFAULT(pru->pru_disconnect, pru_disconnect_notsupp);
	DEFAULT(pru->pru_disconnectx, pru_disconnectx_notsupp);
	DEFAULT(pru->pru_listen, pru_listen_notsupp);
	DEFAULT(pru->pru_peeraddr, pru_peeraddr_notsupp);
	DEFAULT(pru->pru_rcvd, pru_rcvd_notsupp);
	DEFAULT(pru->pru_rcvoob, pru_rcvoob_notsupp);
	DEFAULT(pru->pru_send, pru_send_notsupp);
	DEFAULT(pru->pru_send_list, pru_send_list_notsupp);
	DEFAULT(pru->pru_sense, pru_sense_null);
	DEFAULT(pru->pru_shutdown, pru_shutdown_notsupp);
	DEFAULT(pru->pru_sockaddr, pru_sockaddr_notsupp);
	DEFAULT(pru->pru_sopoll, pru_sopoll_notsupp);
	DEFAULT(pru->pru_soreceive, pru_soreceive_notsupp);
	DEFAULT(pru->pru_sosend, pru_sosend_notsupp);
	DEFAULT(pru->pru_sosend_list, pru_sosend_list_notsupp);
	DEFAULT(pru->pru_socheckopt, pru_socheckopt_null);
	DEFAULT(pru->pru_preconnect, pru_preconnect_null);
	DEFAULT(pru->pru_defunct, pru_defunct_null);
#undef DEFAULT
}

/*
 * The following are macros on BSD and functions on Darwin
 */

/*
 * Do we need to notify the other side when I/O is possible?
 */

int
sb_notify(struct sockbuf *sb)
{
	return sb->sb_waiters > 0 ||
	       (sb->sb_flags & (SB_SEL | SB_ASYNC | SB_UPCALL | SB_KNOTE));
}

/*
 * How much space is there in a socket buffer (so->so_snd or so->so_rcv)?
 * This is problematical if the fields are unsigned, as the space might
 * still be negative (cc > hiwat or mbcnt > mbmax).  Should detect
 * overflow and return 0.
 */
int
sbspace(struct sockbuf *sb)
{
	int pending = 0;
	int space;

	if (sb->sb_flags & SB_KCTL) {
		space = (int)(sb->sb_hiwat - sb->sb_cc);
	} else {
		space = imin((int)(sb->sb_hiwat - sb->sb_cc),
		    (int)(sb->sb_mbmax - sb->sb_mbcnt));
	}
	if (sb->sb_preconn_hiwat != 0) {
		space = imin((int)(sb->sb_preconn_hiwat - sb->sb_cc), space);
	}

	if (space < 0) {
		space = 0;
	}

	/* Compensate for data being processed by content filters */
#if CONTENT_FILTER
	pending = cfil_sock_data_space(sb);
#endif /* CONTENT_FILTER */
	if (pending > space) {
		space = 0;
	} else {
		space -= pending;
	}

	return space;
}

/* do we have to send all at once on a socket? */
int
sosendallatonce(struct socket *so)
{
	return so->so_proto->pr_flags & PR_ATOMIC;
}

/* can we read something from so? */
int
soreadable(struct socket *so)
{
	return so->so_rcv.sb_cc >= so->so_rcv.sb_lowat ||
	       ((so->so_state & SS_CANTRCVMORE)
#if CONTENT_FILTER
	       && cfil_sock_data_pending(&so->so_rcv) == 0
#endif /* CONTENT_FILTER */
	       ) ||
	       so->so_comp.tqh_first || so->so_error;
}

/* can we write something to so? */

int
sowriteable(struct socket *so)
{
	if ((so->so_state & SS_CANTSENDMORE) ||
	    so->so_error > 0) {
		return 1;
	}
	if (so_wait_for_if_feedback(so) || !socanwrite(so)) {
		return 0;
	}
	if (so->so_flags1 & SOF1_PRECONNECT_DATA) {
		return 1;
	}

	int64_t data = sbspace(&so->so_snd);
	int64_t lowat = so->so_snd.sb_lowat;
	/*
	 * Deal with connected UNIX domain sockets which
	 * rely on the fact that the sender's socket buffer is
	 * actually the receiver's socket buffer.
	 */
	if (SOCK_DOM(so) == PF_LOCAL) {
		struct unpcb *unp = sotounpcb(so);
		if (unp != NULL && unp->unp_conn != NULL &&
		    unp->unp_conn->unp_socket != NULL) {
			struct socket *so2 = unp->unp_conn->unp_socket;
			/*
			 * At this point we know that `so' is locked
			 * and that `unp_conn` isn't going to change.
			 * However, we don't lock `so2` because doing so
			 * may require unlocking `so'
			 * (see unp_get_locks_in_order()).
			 *
			 * Two cases can happen:
			 *
			 * 1) we return 1 and tell the application that
			 *    it can write.  Meanwhile, another thread
			 *    fills up the socket buffer.  This will either
			 *    lead to a blocking send or EWOULDBLOCK
			 *    which the application should deal with.
			 * 2) we return 0 and tell the application that
			 *    the socket is not writable.  Meanwhile,
			 *    another thread depletes the receive socket
			 *    buffer. In this case the application will
			 *    be woken up by sb_notify().
			 *
			 * MIN() is required because otherwise sosendcheck()
			 * may return EWOULDBLOCK since it only considers
			 * so->so_snd.
			 */
			data = MIN(data, sbspace(&so2->so_rcv));
		}
	}

	if (data >= lowat) {
		if (so->so_flags & SOF_NOTSENT_LOWAT) {
			if ((SOCK_DOM(so) == PF_INET6 ||
			    SOCK_DOM(so) == PF_INET) &&
			    so->so_type == SOCK_STREAM) {
				return tcp_notsent_lowat_check(so);
			}
#if MPTCP
			else if ((SOCK_DOM(so) == PF_MULTIPATH) &&
			    (SOCK_PROTO(so) == IPPROTO_TCP)) {
				return mptcp_notsent_lowat_check(so);
			}
#endif
			else {
				return 1;
			}
		} else {
			return 1;
		}
	}
	return 0;
}

/* adjust counters in sb reflecting allocation of m */

void
sballoc(struct sockbuf *sb, struct mbuf *m)
{
	sb->sb_cc += m->m_len;
	if (!m_has_mtype(m, MTF_DATA | MTF_HEADER | MTF_OOBDATA)) {
		sb->sb_ctl += m->m_len;
	}
	sb->sb_mbcnt += _MSIZE;

	if (m->m_flags & M_EXT) {
		sb->sb_mbcnt += m->m_ext.ext_size;
	}

	/*
	 * If data is being added to the send socket buffer,
	 * update the send byte count
	 */
	if (sb->sb_flags & SB_SNDBYTE_CNT) {
		inp_incr_sndbytes_total(sb->sb_so, m->m_len);
		inp_incr_sndbytes_unsent(sb->sb_so, m->m_len);
	}
}

/* adjust counters in sb reflecting freeing of m */
void
sbfree(struct sockbuf *sb, struct mbuf *m)
{
	sb->sb_cc -= m->m_len;
	if (!m_has_mtype(m, MTF_DATA | MTF_HEADER | MTF_OOBDATA)) {
		sb->sb_ctl -= m->m_len;
	}
	sb->sb_mbcnt -= _MSIZE;
	if (m->m_flags & M_EXT) {
		sb->sb_mbcnt -= m->m_ext.ext_size;
	}

	/*
	 * If data is being removed from the send socket buffer,
	 * update the send byte count
	 */
	if (sb->sb_flags & SB_SNDBYTE_CNT) {
		inp_decr_sndbytes_total(sb->sb_so, m->m_len);
	}

	if (sb->sb_flags & SB_SENDHEAD) {
		if (m == sb->sb_sendhead) {
			sb->sb_sendhead = NULL;
		}
	}
}

/*
 * Set lock on sockbuf sb; sleep if lock is already held.
 * Unless SB_NOINTR is set on sockbuf, sleep is interruptible.
 * Returns error without lock if sleep is interrupted.
 */
int
sblock(struct sockbuf *sb, uint32_t flags)
{
	boolean_t nointr = ((sb->sb_flags & SB_NOINTR) || (flags & SBL_NOINTR));
	void *__single lr_saved = __unsafe_forge_single(void *, __builtin_return_address(0));
	struct socket *so = sb->sb_so;
	void * wchan;
	int error = 0;
	thread_t __single tp = current_thread();

	VERIFY((flags & SBL_VALID) == flags);

	/* so_usecount may be 0 if we get here from sofreelastref() */
	if (so == NULL) {
		panic("%s: null so, sb=%p sb_flags=0x%x lr=%p",
		    __func__, sb, sb->sb_flags, lr_saved);
		/* NOTREACHED */
	} else if (so->so_usecount < 0) {
		panic("%s: sb=%p sb_flags=0x%x sb_so=%p usecount=%d lr=%p "
		    "lrh= %s\n", __func__, sb, sb->sb_flags, so,
		    so->so_usecount, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	/*
	 * The content filter thread must hold the sockbuf lock
	 */
	if ((so->so_flags & SOF_CONTENT_FILTER) && sb->sb_cfil_thread == tp) {
		/*
		 * Don't panic if we are defunct because SB_LOCK has
		 * been cleared by sodefunct()
		 */
		if (!(so->so_flags & SOF_DEFUNCT) && !(sb->sb_flags & SB_LOCK)) {
			panic("%s: SB_LOCK not held for %p",
			    __func__, sb);
		}

		/* Keep the sockbuf locked */
		return 0;
	}

	if ((sb->sb_flags & SB_LOCK) && !(flags & SBL_WAIT)) {
		return EWOULDBLOCK;
	}
	/*
	 * We may get here from sorflush(), in which case "sb" may not
	 * point to the real socket buffer.  Use the actual socket buffer
	 * address from the socket instead.
	 */
	wchan = (sb->sb_flags & SB_RECV) ?
	    &so->so_rcv.sb_flags : &so->so_snd.sb_flags;

	/*
	 * A content filter thread has exclusive access to the sockbuf
	 * until it clears the
	 */
	while ((sb->sb_flags & SB_LOCK) ||
	    ((so->so_flags & SOF_CONTENT_FILTER) &&
	    sb->sb_cfil_thread != NULL)) {
		lck_mtx_t *mutex_held;

		/*
		 * XXX: This code should be moved up above outside of this loop;
		 * however, we may get here as part of sofreelastref(), and
		 * at that time pr_getlock() may no longer be able to return
		 * us the lock.  This will be fixed in future.
		 */
		if (so->so_proto->pr_getlock != NULL) {
			mutex_held = (*so->so_proto->pr_getlock)(so, PR_F_WILLUNLOCK);
		} else {
			mutex_held = so->so_proto->pr_domain->dom_mtx;
		}

		LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);

		sb->sb_wantlock++;
		VERIFY(sb->sb_wantlock != 0);

		error = msleep(wchan, mutex_held,
		    nointr ? PSOCK : PSOCK | PCATCH,
		    nointr ? "sb_lock_nointr" : "sb_lock", NULL);

		VERIFY(sb->sb_wantlock != 0);
		sb->sb_wantlock--;

		if (error == 0 && (so->so_flags & SOF_DEFUNCT) &&
		    !(flags & SBL_IGNDEFUNCT)) {
			error = EBADF;
			SODEFUNCTLOG("%s[%d, %s]: defunct so 0x%llu [%d,%d] "
			    "(%d)\n", __func__, proc_selfpid(),
			    proc_best_name(current_proc()),
			    so->so_gencnt,
			    SOCK_DOM(so), SOCK_TYPE(so), error);
		}

		if (error != 0) {
			return error;
		}
	}
	sb->sb_flags |= SB_LOCK;
	return 0;
}

/*
 * Release lock on sockbuf sb
 */
void
sbunlock(struct sockbuf *sb, boolean_t keeplocked)
{
	void *__single lr_saved = __unsafe_forge_single(void *, __builtin_return_address(0));
	struct socket *so = sb->sb_so;
	thread_t __single tp = current_thread();

	/* so_usecount may be 0 if we get here from sofreelastref() */
	if (so == NULL) {
		panic("%s: null so, sb=%p sb_flags=0x%x lr=%p",
		    __func__, sb, sb->sb_flags, lr_saved);
		/* NOTREACHED */
	} else if (so->so_usecount < 0) {
		panic("%s: sb=%p sb_flags=0x%x sb_so=%p usecount=%d lr=%p "
		    "lrh= %s\n", __func__, sb, sb->sb_flags, so,
		    so->so_usecount, lr_saved, solockhistory_nr(so));
		/* NOTREACHED */
	}

	/*
	 * The content filter thread must hold the sockbuf lock
	 */
	if ((so->so_flags & SOF_CONTENT_FILTER) && sb->sb_cfil_thread == tp) {
		/*
		 * Don't panic if we are defunct because SB_LOCK has
		 * been cleared by sodefunct()
		 */
		if (!(so->so_flags & SOF_DEFUNCT) &&
		    !(sb->sb_flags & SB_LOCK) &&
		    !(so->so_state & SS_DEFUNCT) &&
		    !(so->so_flags1 & SOF1_DEFUNCTINPROG)) {
			panic("%s: SB_LOCK not held for %p",
			    __func__, sb);
		}
		/* Keep the sockbuf locked and proceed */
	} else {
		VERIFY((sb->sb_flags & SB_LOCK) ||
		    (so->so_state & SS_DEFUNCT) ||
		    (so->so_flags1 & SOF1_DEFUNCTINPROG));

		sb->sb_flags &= ~SB_LOCK;

		if (sb->sb_wantlock > 0) {
			/*
			 * We may get here from sorflush(), in which case "sb"
			 * may not point to the real socket buffer.  Use the
			 * actual socket buffer address from the socket instead.
			 */
			wakeup((sb->sb_flags & SB_RECV) ? &so->so_rcv.sb_flags :
			    &so->so_snd.sb_flags);
		}
	}

	if (!keeplocked) {      /* unlock on exit */
		if (so->so_flags & SOF_MP_SUBFLOW || SOCK_DOM(so) == PF_MULTIPATH) {
			(*so->so_proto->pr_unlock)(so, 1, lr_saved);
		} else {
			lck_mtx_t *mutex_held;

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

			LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);

			VERIFY(so->so_usecount > 0);
			so->so_usecount--;
			so->unlock_lr[so->next_unlock_lr] = lr_saved;
			so->next_unlock_lr = (so->next_unlock_lr + 1) % SO_LCKDBG_MAX;
			lck_mtx_unlock(mutex_held);
		}
	}
}

void
sorwakeup(struct socket *so)
{
	if (sb_notify(&so->so_rcv)) {
		sowakeup(so, &so->so_rcv, NULL);
	}
}

void
sowwakeup(struct socket *so)
{
	if (sb_notify(&so->so_snd)) {
		sowakeup(so, &so->so_snd, NULL);
	}
}

static void
soevupcall(struct socket *so, uint32_t hint)
{
	if (so->so_event != NULL) {
		caddr_t __single so_eventarg = so->so_eventarg;

		hint &= so->so_eventmask;
		if (hint != 0) {
			so->so_event(so, so_eventarg, hint);
		}
	}
}

void
soevent(struct socket *so, uint32_t hint)
{
	if (net_wake_pkt_debug > 0 && (hint & SO_FILT_HINT_WAKE_PKT)) {
		os_log(OS_LOG_DEFAULT, "%s: SO_FILT_HINT_WAKE_PKT so %p",
		    __func__, so);
	}

	if (so->so_flags & SOF_KNOTE) {
		KNOTE(&so->so_klist, hint);
	}

	soevupcall(so, hint);

	/*
	 * Don't post an event if this a subflow socket or
	 * the app has opted out of using cellular interface
	 */
	if ((hint & SO_FILT_HINT_IFDENIED) &&
	    !(so->so_flags & SOF_MP_SUBFLOW) &&
	    !(so->so_restrictions & SO_RESTRICT_DENY_CELLULAR) &&
	    !(so->so_restrictions & SO_RESTRICT_DENY_EXPENSIVE) &&
	    !(so->so_restrictions & SO_RESTRICT_DENY_CONSTRAINED)) {
		soevent_ifdenied(so);
	}
}

static void
soevent_ifdenied(struct socket *so)
{
	struct kev_netpolicy_ifdenied ev_ifdenied;

	bzero(&ev_ifdenied, sizeof(ev_ifdenied));
	/*
	 * The event consumer is interested about the effective {upid,pid,uuid}
	 * info which can be different than the those related to the process
	 * that recently performed a system call on the socket, i.e. when the
	 * socket is delegated.
	 */
	if (so->so_flags & SOF_DELEGATED) {
		ev_ifdenied.ev_data.eupid = so->e_upid;
		ev_ifdenied.ev_data.epid = so->e_pid;
		uuid_copy(ev_ifdenied.ev_data.euuid, so->e_uuid);
	} else {
		ev_ifdenied.ev_data.eupid = so->last_upid;
		ev_ifdenied.ev_data.epid = so->last_pid;
		uuid_copy(ev_ifdenied.ev_data.euuid, so->last_uuid);
	}

	if (++so->so_ifdenied_notifies > 1) {
		/*
		 * Allow for at most one kernel event to be generated per
		 * socket; so_ifdenied_notifies is reset upon changes in
		 * the UUID policy.  See comments in inp_update_policy.
		 */
		if (net_io_policy_log) {
			uuid_string_t buf;

			uuid_unparse(ev_ifdenied.ev_data.euuid, buf);
			log(LOG_DEBUG, "%s[%d]: so %llu [%d,%d] epid %llu "
			    "euuid %s%s has %d redundant events supressed\n",
			    __func__, so->last_pid,
			    so->so_gencnt, SOCK_DOM(so),
			    SOCK_TYPE(so), ev_ifdenied.ev_data.epid, buf,
			    ((so->so_flags & SOF_DELEGATED) ?
			    " [delegated]" : ""), so->so_ifdenied_notifies);
		}
	} else {
		if (net_io_policy_log) {
			uuid_string_t buf;

			uuid_unparse(ev_ifdenied.ev_data.euuid, buf);
			log(LOG_DEBUG, "%s[%d]: so %llu [%d,%d] epid %llu "
			    "euuid %s%s event posted\n", __func__,
			    so->last_pid, so->so_gencnt,
			    SOCK_DOM(so), SOCK_TYPE(so),
			    ev_ifdenied.ev_data.epid, buf,
			    ((so->so_flags & SOF_DELEGATED) ?
			    " [delegated]" : ""));
		}
		netpolicy_post_msg(KEV_NETPOLICY_IFDENIED, &ev_ifdenied.ev_data,
		    sizeof(ev_ifdenied));
	}
}

/*
 * Make a copy of a sockaddr in a malloced buffer of type SONAME.
 */
struct sockaddr *
dup_sockaddr(struct sockaddr *sa, int canwait)
{
	struct sockaddr *sa2;

	sa2 = SA(alloc_sockaddr(sa->sa_len, canwait ? Z_WAITOK : Z_NOWAIT));
	if (sa2 != NULL) {
		SOCKADDR_COPY(sa, sa2, sa->sa_len);
	}
	return sa2;
}

/*
 * 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)
{
	xso->xso_len = sizeof(*xso);
	xso->xso_so = (_XSOCKET_PTR(struct socket *))VM_KERNEL_ADDRHASH(so);
	xso->so_type = so->so_type;
	xso->so_options = (short)(so->so_options & 0xffff);
	xso->so_linger = so->so_linger;
	xso->so_state = so->so_state;
	xso->so_pcb = (_XSOCKET_PTR(caddr_t))VM_KERNEL_ADDRHASH(so->so_pcb);
	if (so->so_proto) {
		xso->xso_protocol = SOCK_PROTO(so);
		xso->xso_family = SOCK_DOM(so);
	} else {
		xso->xso_protocol = xso->xso_family = 0;
	}
	xso->so_qlen = so->so_qlen;
	xso->so_incqlen = so->so_incqlen;
	xso->so_qlimit = so->so_qlimit;
	xso->so_timeo = so->so_timeo;
	xso->so_error = so->so_error;
	xso->so_pgid = so->so_pgid;
	xso->so_oobmark = so->so_oobmark;
	sbtoxsockbuf(&so->so_snd, &xso->so_snd);
	sbtoxsockbuf(&so->so_rcv, &xso->so_rcv);
	xso->so_uid = kauth_cred_getuid(so->so_cred);
}


#if XNU_TARGET_OS_OSX

void
sotoxsocket64(struct socket *so, struct xsocket64 *xso)
{
	xso->xso_len = sizeof(*xso);
	xso->xso_so = (u_int64_t)VM_KERNEL_ADDRHASH(so);
	xso->so_type = so->so_type;
	xso->so_options = (short)(so->so_options & 0xffff);
	xso->so_linger = so->so_linger;
	xso->so_state = so->so_state;
	xso->so_pcb = (u_int64_t)VM_KERNEL_ADDRHASH(so->so_pcb);
	if (so->so_proto) {
		xso->xso_protocol = SOCK_PROTO(so);
		xso->xso_family = SOCK_DOM(so);
	} else {
		xso->xso_protocol = xso->xso_family = 0;
	}
	xso->so_qlen = so->so_qlen;
	xso->so_incqlen = so->so_incqlen;
	xso->so_qlimit = so->so_qlimit;
	xso->so_timeo = so->so_timeo;
	xso->so_error = so->so_error;
	xso->so_pgid = so->so_pgid;
	xso->so_oobmark = so->so_oobmark;
	sbtoxsockbuf(&so->so_snd, &xso->so_snd);
	sbtoxsockbuf(&so->so_rcv, &xso->so_rcv);
	xso->so_uid = kauth_cred_getuid(so->so_cred);
}

#endif /* XNU_TARGET_OS_OSX */

/*
 * This does the same for sockbufs.  Note that the xsockbuf structure,
 * since it is always embedded in a socket, does not include a self
 * pointer nor a length.  We make this entry point public in case
 * some other mechanism needs it.
 */
void
sbtoxsockbuf(struct sockbuf *sb, struct xsockbuf *xsb)
{
	xsb->sb_cc = sb->sb_cc;
	xsb->sb_hiwat = sb->sb_hiwat;
	xsb->sb_mbcnt = sb->sb_mbcnt;
	xsb->sb_mbmax = sb->sb_mbmax;
	xsb->sb_lowat = sb->sb_lowat;
	xsb->sb_flags = (short)sb->sb_flags;
	xsb->sb_timeo = (short)
	    ((sb->sb_timeo.tv_sec * hz) + sb->sb_timeo.tv_usec / tick);
	if (xsb->sb_timeo == 0 && sb->sb_timeo.tv_usec != 0) {
		xsb->sb_timeo = 1;
	}
}

/*
 * Based on the policy set by an all knowing decison maker, throttle sockets
 * that either have been marked as belonging to "background" process.
 */
inline int
soisthrottled(struct socket *so)
{
	return so->so_flags1 & SOF1_TRAFFIC_MGT_SO_BACKGROUND;
}

inline int
soisprivilegedtraffic(struct socket *so)
{
	return (so->so_flags & SOF_PRIVILEGED_TRAFFIC_CLASS) ? 1 : 0;
}

inline int
soissrcbackground(struct socket *so)
{
	return (so->so_flags1 & SOF1_TRAFFIC_MGT_SO_BACKGROUND) ||
	       IS_SO_TC_BACKGROUND(so->so_traffic_class);
}

inline int
soissrcrealtime(struct socket *so)
{
	return so->so_traffic_class >= SO_TC_AV &&
	       so->so_traffic_class <= SO_TC_VO;
}

inline int
soissrcbesteffort(struct socket *so)
{
	return so->so_traffic_class == SO_TC_BE ||
	       so->so_traffic_class == SO_TC_RD ||
	       so->so_traffic_class == SO_TC_OAM;
}

void
soclearfastopen(struct socket *so)
{
	if (so->so_flags1 & SOF1_PRECONNECT_DATA) {
		so->so_flags1 &= ~SOF1_PRECONNECT_DATA;
	}

	if (so->so_flags1 & SOF1_DATA_IDEMPOTENT) {
		so->so_flags1 &= ~SOF1_DATA_IDEMPOTENT;
	}
}

void
sonullevent(struct socket *so, void *arg, uint32_t hint)
{
#pragma unused(so, arg, hint)
}

/*
 * Here is the definition of some of the basic objects in the kern.ipc
 * branch of the MIB.
 */
SYSCTL_NODE(_kern, KERN_IPC, ipc,
    CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_ANYBODY, 0, "IPC");

/* Check that the maximum socket buffer size is within a range */

static int
sysctl_sb_max SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
	u_int32_t new_value;
	int changed = 0;
	int error = sysctl_io_number(req, sb_max, sizeof(u_int32_t),
	    &new_value, &changed);
	if (!error && changed) {
		if (new_value > LOW_SB_MAX && new_value <= high_sb_max) {
			sb_max = new_value;
		} else {
			error = ERANGE;
		}
	}
	return error;
}

SYSCTL_PROC(_kern_ipc, KIPC_MAXSOCKBUF, maxsockbuf,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
    &sb_max, 0, &sysctl_sb_max, "IU", "Maximum socket buffer size");

SYSCTL_INT(_kern_ipc, KIPC_SOCKBUF_WASTE, sockbuf_waste_factor,
    CTLFLAG_RW | CTLFLAG_LOCKED, &sb_efficiency, 0, "");

SYSCTL_INT(_kern_ipc, KIPC_NMBCLUSTERS, nmbclusters,
    CTLFLAG_RD | CTLFLAG_LOCKED, &nmbclusters, 0, "");

SYSCTL_INT(_kern_ipc, OID_AUTO, njcl,
    CTLFLAG_RD | CTLFLAG_LOCKED, &njcl, 0, "");

SYSCTL_INT(_kern_ipc, OID_AUTO, njclbytes,
    CTLFLAG_RD | CTLFLAG_LOCKED, &njclbytes, 0, "");

SYSCTL_INT(_kern_ipc, KIPC_SOQLIMITCOMPAT, soqlimitcompat,
    CTLFLAG_RW | CTLFLAG_LOCKED, &soqlimitcompat, 1,
    "Enable socket queue limit compatibility");

/*
 * Hack alert -- rdar://33572856
 * A loopback test we cannot change was failing because it sets
 * SO_SENDTIMEO to 5 seconds and that's also the value
 * of the minimum persist timer. Because of the persist timer,
 * the connection was not idle for 5 seconds and SO_SNDTIMEO
 * was not triggering at 5 seconds causing the test failure.
 * As a workaround we check the sysctl soqlencomp the test is already
 * setting to set disable auto tuning of the receive buffer.
 */

extern u_int32_t tcp_do_autorcvbuf;

static int
sysctl_soqlencomp SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
	u_int32_t new_value;
	int changed = 0;
	int error = sysctl_io_number(req, soqlencomp, sizeof(u_int32_t),
	    &new_value, &changed);
	if (!error && changed) {
		soqlencomp = new_value;
		if (new_value != 0) {
			tcp_do_autorcvbuf = 0;
			tcptv_persmin_val = 6 * TCP_RETRANSHZ;
		}
	}
	return error;
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, soqlencomp,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
    &soqlencomp, 0, &sysctl_soqlencomp, "IU", "");

SYSCTL_NODE(_kern_ipc, OID_AUTO, io_policy, CTLFLAG_RW, 0, "network IO policy");

SYSCTL_INT(_kern_ipc_io_policy, OID_AUTO, log, CTLFLAG_RW | CTLFLAG_LOCKED,
    &net_io_policy_log, 0, "");

#if CONFIG_PROC_UUID_POLICY
SYSCTL_INT(_kern_ipc_io_policy, OID_AUTO, uuid, CTLFLAG_RW | CTLFLAG_LOCKED,
    &net_io_policy_uuid, 0, "");
#endif /* CONFIG_PROC_UUID_POLICY */