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File: [cvs.NetBSD.org] / src / sys / kern / uipc_socket.c (download)

Revision 1.205, Sat Jul 2 17:53:50 2011 UTC (3 years, 4 months ago) by bouyer
Branch: MAIN
CVS Tags: yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, jmcneill-usbmp-pre-base2, jmcneill-usbmp-base, jmcneill-audiomp3-base, jmcneill-audiomp3
Branch point for: yamt-pagecache, jmcneill-usbmp
Changes since 1.204: +46 -66 lines

Fix kern/45093 as discussed on tech-kern@:
http://mail-index.netbsd.org/tech-kern/2011/06/17/msg010734.html

The cause of the problem is that the so_pendfree is processed with
the softnet_lock held at one point, and processing the list
calls sodoloanfree() which may kpause(). As the thread sleeps with
softnet_lock held, it ultimately cause a deadlock (see the PR or tech-kern
thread for details).
Although it should be possible to call sodopendfree() after releasing
the socket lock, it's not so easy to know where he socket lock is held and
where it's not, so we may hit the issue again later.
Add a kernel thread to handle the so_pendfree list, and wake up this
thread when adding mbufs to this list. Get rid of the various sodopendfree()
calls, hopefully fixing definitively the problem.

/*	$NetBSD: uipc_socket.c,v 1.205 2011/07/02 17:53:50 bouyer Exp $	*/

/*-
 * Copyright (c) 2002, 2007, 2008, 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of Wasabi Systems, Inc, and by Andrew Doran.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 2004 The FreeBSD Foundation
 * Copyright (c) 2004 Robert Watson
 * 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. 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_socket.c	8.6 (Berkeley) 5/2/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uipc_socket.c,v 1.205 2011/07/02 17:53:50 bouyer Exp $");

#include "opt_compat_netbsd.h"
#include "opt_sock_counters.h"
#include "opt_sosend_loan.h"
#include "opt_mbuftrace.h"
#include "opt_somaxkva.h"
#include "opt_multiprocessor.h"	/* XXX */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/uidinfo.h>
#include <sys/event.h>
#include <sys/poll.h>
#include <sys/kauth.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/kthread.h>

#ifdef COMPAT_50
#include <compat/sys/time.h>
#include <compat/sys/socket.h>
#endif

#include <uvm/uvm_extern.h>
#include <uvm/uvm_loan.h>
#include <uvm/uvm_page.h>

MALLOC_DEFINE(M_SOOPTS, "soopts", "socket options");
MALLOC_DEFINE(M_SONAME, "soname", "socket name");

extern const struct fileops socketops;

extern int	somaxconn;			/* patchable (XXX sysctl) */
int		somaxconn = SOMAXCONN;
kmutex_t	*softnet_lock;

#ifdef SOSEND_COUNTERS
#include <sys/device.h>

static struct evcnt sosend_loan_big = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    NULL, "sosend", "loan big");
static struct evcnt sosend_copy_big = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    NULL, "sosend", "copy big");
static struct evcnt sosend_copy_small = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    NULL, "sosend", "copy small");
static struct evcnt sosend_kvalimit = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    NULL, "sosend", "kva limit");

#define	SOSEND_COUNTER_INCR(ev)		(ev)->ev_count++

EVCNT_ATTACH_STATIC(sosend_loan_big);
EVCNT_ATTACH_STATIC(sosend_copy_big);
EVCNT_ATTACH_STATIC(sosend_copy_small);
EVCNT_ATTACH_STATIC(sosend_kvalimit);
#else

#define	SOSEND_COUNTER_INCR(ev)		/* nothing */

#endif /* SOSEND_COUNTERS */

static struct callback_entry sokva_reclaimerentry;

#if defined(SOSEND_NO_LOAN) || defined(MULTIPROCESSOR)
int sock_loan_thresh = -1;
#else
int sock_loan_thresh = 4096;
#endif

static kmutex_t so_pendfree_lock;
static struct mbuf *so_pendfree = NULL;

#ifndef SOMAXKVA
#define	SOMAXKVA (16 * 1024 * 1024)
#endif
int somaxkva = SOMAXKVA;
static int socurkva;
static kcondvar_t socurkva_cv;

static kauth_listener_t socket_listener;

#define	SOCK_LOAN_CHUNK		65536

static void sopendfree_thread(void *);
static kcondvar_t pendfree_thread_cv;
static lwp_t *sopendfree_lwp;

static void sysctl_kern_somaxkva_setup(void);
static struct sysctllog *socket_sysctllog;

static vsize_t
sokvareserve(struct socket *so, vsize_t len)
{
	int error;

	mutex_enter(&so_pendfree_lock);
	while (socurkva + len > somaxkva) {
		SOSEND_COUNTER_INCR(&sosend_kvalimit);
		error = cv_wait_sig(&socurkva_cv, &so_pendfree_lock);
		if (error) {
			len = 0;
			break;
		}
	}
	socurkva += len;
	mutex_exit(&so_pendfree_lock);
	return len;
}

static void
sokvaunreserve(vsize_t len)
{

	mutex_enter(&so_pendfree_lock);
	socurkva -= len;
	cv_broadcast(&socurkva_cv);
	mutex_exit(&so_pendfree_lock);
}

/*
 * sokvaalloc: allocate kva for loan.
 */

vaddr_t
sokvaalloc(vsize_t len, struct socket *so)
{
	vaddr_t lva;

	/*
	 * reserve kva.
	 */

	if (sokvareserve(so, len) == 0)
		return 0;

	/*
	 * allocate kva.
	 */

	lva = uvm_km_alloc(kernel_map, len, 0, UVM_KMF_VAONLY | UVM_KMF_WAITVA);
	if (lva == 0) {
		sokvaunreserve(len);
		return (0);
	}

	return lva;
}

/*
 * sokvafree: free kva for loan.
 */

void
sokvafree(vaddr_t sva, vsize_t len)
{

	/*
	 * free kva.
	 */

	uvm_km_free(kernel_map, sva, len, UVM_KMF_VAONLY);

	/*
	 * unreserve kva.
	 */

	sokvaunreserve(len);
}

static void
sodoloanfree(struct vm_page **pgs, void *buf, size_t size)
{
	vaddr_t sva, eva;
	vsize_t len;
	int npgs;

	KASSERT(pgs != NULL);

	eva = round_page((vaddr_t) buf + size);
	sva = trunc_page((vaddr_t) buf);
	len = eva - sva;
	npgs = len >> PAGE_SHIFT;

	pmap_kremove(sva, len);
	pmap_update(pmap_kernel());
	uvm_unloan(pgs, npgs, UVM_LOAN_TOPAGE);
	sokvafree(sva, len);
}

/*
 * sopendfree_thread: free mbufs on "pendfree" list.
 * unlock and relock so_pendfree_lock when freeing mbufs.
 */

static void
sopendfree_thread(void *v)
{
	struct mbuf *m, *next;
	size_t rv;

	mutex_enter(&so_pendfree_lock);

	for (;;) {
		rv = 0;
		while (so_pendfree != NULL) {
			m = so_pendfree;
			so_pendfree = NULL;
			mutex_exit(&so_pendfree_lock);

			for (; m != NULL; m = next) {
				next = m->m_next;
				KASSERT((~m->m_flags & (M_EXT|M_EXT_PAGES)) == 0);
				KASSERT(m->m_ext.ext_refcnt == 0);

				rv += m->m_ext.ext_size;
				sodoloanfree(m->m_ext.ext_pgs, m->m_ext.ext_buf,
				    m->m_ext.ext_size);
				pool_cache_put(mb_cache, m);
			}

			mutex_enter(&so_pendfree_lock);
		}
		if (rv)
			cv_broadcast(&socurkva_cv);
		cv_wait(&pendfree_thread_cv, &so_pendfree_lock);
	}
	panic("sopendfree_thread");
	/* NOTREACHED */
}

void
soloanfree(struct mbuf *m, void *buf, size_t size, void *arg)
{

	KASSERT(m != NULL);

	/*
	 * postpone freeing mbuf.
	 *
	 * we can't do it in interrupt context
	 * because we need to put kva back to kernel_map.
	 */

	mutex_enter(&so_pendfree_lock);
	m->m_next = so_pendfree;
	so_pendfree = m;
	cv_signal(&pendfree_thread_cv);
	mutex_exit(&so_pendfree_lock);
}

static long
sosend_loan(struct socket *so, struct uio *uio, struct mbuf *m, long space)
{
	struct iovec *iov = uio->uio_iov;
	vaddr_t sva, eva;
	vsize_t len;
	vaddr_t lva;
	int npgs, error;
	vaddr_t va;
	int i;

	if (VMSPACE_IS_KERNEL_P(uio->uio_vmspace))
		return (0);

	if (iov->iov_len < (size_t) space)
		space = iov->iov_len;
	if (space > SOCK_LOAN_CHUNK)
		space = SOCK_LOAN_CHUNK;

	eva = round_page((vaddr_t) iov->iov_base + space);
	sva = trunc_page((vaddr_t) iov->iov_base);
	len = eva - sva;
	npgs = len >> PAGE_SHIFT;

	KASSERT(npgs <= M_EXT_MAXPAGES);

	lva = sokvaalloc(len, so);
	if (lva == 0)
		return 0;

	error = uvm_loan(&uio->uio_vmspace->vm_map, sva, len,
	    m->m_ext.ext_pgs, UVM_LOAN_TOPAGE);
	if (error) {
		sokvafree(lva, len);
		return (0);
	}

	for (i = 0, va = lva; i < npgs; i++, va += PAGE_SIZE)
		pmap_kenter_pa(va, VM_PAGE_TO_PHYS(m->m_ext.ext_pgs[i]),
		    VM_PROT_READ, 0);
	pmap_update(pmap_kernel());

	lva += (vaddr_t) iov->iov_base & PAGE_MASK;

	MEXTADD(m, (void *) lva, space, M_MBUF, soloanfree, so);
	m->m_flags |= M_EXT_PAGES | M_EXT_ROMAP;

	uio->uio_resid -= space;
	/* uio_offset not updated, not set/used for write(2) */
	uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + space;
	uio->uio_iov->iov_len -= space;
	if (uio->uio_iov->iov_len == 0) {
		uio->uio_iov++;
		uio->uio_iovcnt--;
	}

	return (space);
}

static int
sokva_reclaim_callback(struct callback_entry *ce, void *obj, void *arg)
{

	KASSERT(ce == &sokva_reclaimerentry);
	KASSERT(obj == NULL);

	if (!vm_map_starved_p(kernel_map)) {
		return CALLBACK_CHAIN_ABORT;
	}
	return CALLBACK_CHAIN_CONTINUE;
}

struct mbuf *
getsombuf(struct socket *so, int type)
{
	struct mbuf *m;

	m = m_get(M_WAIT, type);
	MCLAIM(m, so->so_mowner);
	return m;
}

static int
socket_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
    void *arg0, void *arg1, void *arg2, void *arg3)
{
	int result;
	enum kauth_network_req req;

	result = KAUTH_RESULT_DEFER;
	req = (enum kauth_network_req)arg0;

	if ((action != KAUTH_NETWORK_SOCKET) &&
	    (action != KAUTH_NETWORK_BIND))
		return result;

	switch (req) {
	case KAUTH_REQ_NETWORK_BIND_PORT:
		result = KAUTH_RESULT_ALLOW;
		break;

	case KAUTH_REQ_NETWORK_SOCKET_DROP: {
		/* Normal users can only drop their own connections. */
		struct socket *so = (struct socket *)arg1;

		if (proc_uidmatch(cred, so->so_cred))
			result = KAUTH_RESULT_ALLOW;

		break;
		}

	case KAUTH_REQ_NETWORK_SOCKET_OPEN:
		/* We allow "raw" routing/bluetooth sockets to anyone. */
		if ((u_long)arg1 == PF_ROUTE || (u_long)arg1 == PF_OROUTE
		    || (u_long)arg1 == PF_BLUETOOTH) {
			result = KAUTH_RESULT_ALLOW;
		} else {
			/* Privileged, let secmodel handle this. */
			if ((u_long)arg2 == SOCK_RAW)
				break;
		}

		result = KAUTH_RESULT_ALLOW;

		break;

	case KAUTH_REQ_NETWORK_SOCKET_CANSEE:
		result = KAUTH_RESULT_ALLOW;

		break;

	default:
		break;
	}

	return result;
}

void
soinit(void)
{

	sysctl_kern_somaxkva_setup();

	mutex_init(&so_pendfree_lock, MUTEX_DEFAULT, IPL_VM);
	softnet_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
	cv_init(&socurkva_cv, "sokva");
	cv_init(&pendfree_thread_cv, "sopendfr");
	soinit2();

	/* Set the initial adjusted socket buffer size. */
	if (sb_max_set(sb_max))
		panic("bad initial sb_max value: %lu", sb_max);

	callback_register(&vm_map_to_kernel(kernel_map)->vmk_reclaim_callback,
	    &sokva_reclaimerentry, NULL, sokva_reclaim_callback);

	socket_listener = kauth_listen_scope(KAUTH_SCOPE_NETWORK,
	    socket_listener_cb, NULL);
}

void
soinit1(void)
{
	int error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
	    sopendfree_thread, NULL, &sopendfree_lwp, "sopendfree");
	if (error)
		panic("soinit1 %d", error);
}

/*
 * 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.
 */
/*ARGSUSED*/
int
socreate(int dom, struct socket **aso, int type, int proto, struct lwp *l,
	 struct socket *lockso)
{
	const struct protosw	*prp;
	struct socket	*so;
	uid_t		uid;
	int		error;
	kmutex_t	*lock;

	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_SOCKET,
	    KAUTH_REQ_NETWORK_SOCKET_OPEN, KAUTH_ARG(dom), KAUTH_ARG(type),
	    KAUTH_ARG(proto));
	if (error != 0)
		return error;

	if (proto)
		prp = pffindproto(dom, proto, type);
	else
		prp = pffindtype(dom, type);
	if (prp == NULL) {
		/* no support for domain */
		if (pffinddomain(dom) == 0)
			return EAFNOSUPPORT;
		/* no support for socket type */
		if (proto == 0 && type != 0)
			return EPROTOTYPE;
		return EPROTONOSUPPORT;
	}
	if (prp->pr_usrreq == NULL)
		return EPROTONOSUPPORT;
	if (prp->pr_type != type)
		return EPROTOTYPE;

	so = soget(true);
	so->so_type = type;
	so->so_proto = prp;
	so->so_send = sosend;
	so->so_receive = soreceive;
#ifdef MBUFTRACE
	so->so_rcv.sb_mowner = &prp->pr_domain->dom_mowner;
	so->so_snd.sb_mowner = &prp->pr_domain->dom_mowner;
	so->so_mowner = &prp->pr_domain->dom_mowner;
#endif
	uid = kauth_cred_geteuid(l->l_cred);
	so->so_uidinfo = uid_find(uid);
	so->so_cpid = l->l_proc->p_pid;
	if (lockso != NULL) {
		/* Caller wants us to share a lock. */
		lock = lockso->so_lock;
		so->so_lock = lock;
		mutex_obj_hold(lock);
		mutex_enter(lock);
	} else {
		/* Lock assigned and taken during PRU_ATTACH. */
	}
	error = (*prp->pr_usrreq)(so, PRU_ATTACH, NULL,
	    (struct mbuf *)(long)proto, NULL, l);
	KASSERT(solocked(so));
	if (error != 0) {
		so->so_state |= SS_NOFDREF;
		sofree(so);
		return error;
	}
	so->so_cred = kauth_cred_dup(l->l_cred);
	sounlock(so);
	*aso = so;
	return 0;
}

/* On success, write file descriptor to fdout and return zero.  On
 * failure, return non-zero; *fdout will be undefined.
 */
int
fsocreate(int domain, struct socket **sop, int type, int protocol,
    struct lwp *l, int *fdout)
{
	struct socket	*so;
	struct file	*fp;
	int		fd, error;
	int		flags = type & SOCK_FLAGS_MASK;

	type &= ~SOCK_FLAGS_MASK;
	if ((error = fd_allocfile(&fp, &fd)) != 0)
		return error;
	fd_set_exclose(l, fd, (flags & SOCK_CLOEXEC) != 0);
	fp->f_flag = FREAD|FWRITE|((flags & SOCK_NONBLOCK) ? FNONBLOCK : 0);
	fp->f_type = DTYPE_SOCKET;
	fp->f_ops = &socketops;
	error = socreate(domain, &so, type, protocol, l, NULL);
	if (error != 0) {
		fd_abort(curproc, fp, fd);
	} else {
		if (sop != NULL)
			*sop = so;
		fp->f_data = so;
		fd_affix(curproc, fp, fd);
		*fdout = fd;
	}
	return error;
}

int
sofamily(const struct socket *so)
{
	const struct protosw *pr;
	const struct domain *dom;

	if ((pr = so->so_proto) == NULL)
		return AF_UNSPEC;
	if ((dom = pr->pr_domain) == NULL)
		return AF_UNSPEC;
	return dom->dom_family;
}

int
sobind(struct socket *so, struct mbuf *nam, struct lwp *l)
{
	int	error;

	solock(so);
	error = (*so->so_proto->pr_usrreq)(so, PRU_BIND, NULL, nam, NULL, l);
	sounlock(so);
	return error;
}

int
solisten(struct socket *so, int backlog, struct lwp *l)
{
	int	error;

	solock(so);
	if ((so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING | 
	    SS_ISDISCONNECTING)) != 0) {
	    	sounlock(so);
		return (EOPNOTSUPP);
	}
	error = (*so->so_proto->pr_usrreq)(so, PRU_LISTEN, NULL,
	    NULL, NULL, l);
	if (error != 0) {
		sounlock(so);
		return error;
	}
	if (TAILQ_EMPTY(&so->so_q))
		so->so_options |= SO_ACCEPTCONN;
	if (backlog < 0)
		backlog = 0;
	so->so_qlimit = min(backlog, somaxconn);
	sounlock(so);
	return 0;
}

void
sofree(struct socket *so)
{
	u_int refs;

	KASSERT(solocked(so));

	if (so->so_pcb || (so->so_state & SS_NOFDREF) == 0) {
		sounlock(so);
		return;
	}
	if (so->so_head) {
		/*
		 * We must not decommission a socket that's on the accept(2)
		 * queue.  If we do, then accept(2) may hang after select(2)
		 * indicated that the listening socket was ready.
		 */
		if (!soqremque(so, 0)) {
			sounlock(so);
			return;
		}
	}
	if (so->so_rcv.sb_hiwat)
		(void)chgsbsize(so->so_uidinfo, &so->so_rcv.sb_hiwat, 0,
		    RLIM_INFINITY);
	if (so->so_snd.sb_hiwat)
		(void)chgsbsize(so->so_uidinfo, &so->so_snd.sb_hiwat, 0,
		    RLIM_INFINITY);
	sbrelease(&so->so_snd, so);
	KASSERT(!cv_has_waiters(&so->so_cv));
	KASSERT(!cv_has_waiters(&so->so_rcv.sb_cv));
	KASSERT(!cv_has_waiters(&so->so_snd.sb_cv));
	sorflush(so);
	refs = so->so_aborting;	/* XXX */
	/* Remove acccept filter if one is present. */
	if (so->so_accf != NULL)
		(void)accept_filt_clear(so);
	sounlock(so);
	if (refs == 0)		/* XXX */
		soput(so);
}

/*
 * Close a socket on last file table reference removal.
 * Initiate disconnect if connected.
 * Free socket when disconnect complete.
 */
int
soclose(struct socket *so)
{
	struct socket	*so2;
	int		error;
	int		error2;

	error = 0;
	solock(so);
	if (so->so_options & SO_ACCEPTCONN) {
		for (;;) {
			if ((so2 = TAILQ_FIRST(&so->so_q0)) != 0) {
				KASSERT(solocked2(so, so2));
				(void) soqremque(so2, 0);
				/* soabort drops the lock. */
				(void) soabort(so2);
				solock(so);
				continue;
			}
			if ((so2 = TAILQ_FIRST(&so->so_q)) != 0) {
				KASSERT(solocked2(so, so2));
				(void) soqremque(so2, 1);
				/* soabort drops the lock. */
				(void) soabort(so2);
				solock(so);
				continue;
			}
			break;
		}
	}
	if (so->so_pcb == 0)
		goto discard;
	if (so->so_state & SS_ISCONNECTED) {
		if ((so->so_state & SS_ISDISCONNECTING) == 0) {
			error = sodisconnect(so);
			if (error)
				goto drop;
		}
		if (so->so_options & SO_LINGER) {
			if ((so->so_state & SS_ISDISCONNECTING) && so->so_nbio)
				goto drop;
			while (so->so_state & SS_ISCONNECTED) {
				error = sowait(so, true, so->so_linger * hz);
				if (error)
					break;
			}
		}
	}
 drop:
	if (so->so_pcb) {
		error2 = (*so->so_proto->pr_usrreq)(so, PRU_DETACH,
		    NULL, NULL, NULL, NULL);
		if (error == 0)
			error = error2;
	}
 discard:
	if (so->so_state & SS_NOFDREF)
		panic("soclose: NOFDREF");
	kauth_cred_free(so->so_cred);
	so->so_state |= SS_NOFDREF;
	sofree(so);
	return (error);
}

/*
 * Must be called with the socket locked..  Will return with it unlocked.
 */
int
soabort(struct socket *so)
{
	u_int refs;
	int error;
	
	KASSERT(solocked(so));
	KASSERT(so->so_head == NULL);

	so->so_aborting++;		/* XXX */
	error = (*so->so_proto->pr_usrreq)(so, PRU_ABORT, NULL,
	    NULL, NULL, NULL);
	refs = --so->so_aborting;	/* XXX */
	if (error || (refs == 0)) {
		sofree(so);
	} else {
		sounlock(so);
	}
	return error;
}

int
soaccept(struct socket *so, struct mbuf *nam)
{
	int	error;

	KASSERT(solocked(so));

	error = 0;
	if ((so->so_state & SS_NOFDREF) == 0)
		panic("soaccept: !NOFDREF");
	so->so_state &= ~SS_NOFDREF;
	if ((so->so_state & SS_ISDISCONNECTED) == 0 ||
	    (so->so_proto->pr_flags & PR_ABRTACPTDIS) == 0)
		error = (*so->so_proto->pr_usrreq)(so, PRU_ACCEPT,
		    NULL, nam, NULL, NULL);
	else
		error = ECONNABORTED;

	return (error);
}

int
soconnect(struct socket *so, struct mbuf *nam, struct lwp *l)
{
	int		error;

	KASSERT(solocked(so));

	if (so->so_options & SO_ACCEPTCONN)
		return (EOPNOTSUPP);
	/*
	 * 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.
	 */
	if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
	    ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
	    (error = sodisconnect(so))))
		error = EISCONN;
	else
		error = (*so->so_proto->pr_usrreq)(so, PRU_CONNECT,
		    NULL, nam, NULL, l);
	return (error);
}

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

	KASSERT(solocked2(so1, so2));

	error = (*so1->so_proto->pr_usrreq)(so1, PRU_CONNECT2,
	    NULL, (struct mbuf *)so2, NULL, NULL);
	return (error);
}

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

	KASSERT(solocked(so));

	if ((so->so_state & SS_ISCONNECTED) == 0) {
		error = ENOTCONN;
	} else if (so->so_state & SS_ISDISCONNECTING) {
		error = EALREADY;
	} else {
		error = (*so->so_proto->pr_usrreq)(so, PRU_DISCONNECT,
		    NULL, NULL, NULL, NULL);
	}
	return (error);
}

#define	SBLOCKWAIT(f)	(((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
/*
 * 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.
 */
int
sosend(struct socket *so, struct mbuf *addr, struct uio *uio, struct mbuf *top,
	struct mbuf *control, int flags, struct lwp *l)
{
	struct mbuf	**mp, *m;
	struct proc	*p;
	long		space, len, resid, clen, mlen;
	int		error, s, dontroute, atomic;
	short		wakeup_state = 0;

	p = l->l_proc;
	clen = 0;

	/*
	 * solock() provides atomicity of access.  splsoftnet() prevents
	 * protocol processing soft interrupts from interrupting us and
	 * blocking (expensive).
	 */
	s = splsoftnet();
	solock(so);
	atomic = sosendallatonce(so) || top;
	if (uio)
		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 &&
	    (so->so_proto->pr_flags & PR_ATOMIC);
	l->l_ru.ru_msgsnd++;
	if (control)
		clen = control->m_len;
 restart:
	if ((error = sblock(&so->so_snd, SBLOCKWAIT(flags))) != 0)
		goto out;
	do {
		if (so->so_state & SS_CANTSENDMORE) {
			error = EPIPE;
			goto release;
		}
		if (so->so_error) {
			error = so->so_error;
			so->so_error = 0;
			goto release;
		}
		if ((so->so_state & SS_ISCONNECTED) == 0) {
			if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
				if ((so->so_state & SS_ISCONFIRMING) == 0 &&
				    !(resid == 0 && clen != 0)) {
					error = ENOTCONN;
					goto release;
				}
			} else if (addr == 0) {
				error = EDESTADDRREQ;
				goto release;
			}
		}
		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) {
			error = EMSGSIZE;
			goto release;
		}
		if (space < resid + clen &&
		    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
			if (so->so_nbio) {
				error = EWOULDBLOCK;
				goto release;
			}
			sbunlock(&so->so_snd);
			if (wakeup_state & SS_RESTARTSYS) {
				error = ERESTART;
				goto out;
			}
			error = sbwait(&so->so_snd);
			if (error)
				goto out;
			wakeup_state = so->so_state;
			goto restart;
		}
		wakeup_state = 0;
		mp = &top;
		space -= clen;
		do {
			if (uio == NULL) {
				/*
				 * Data is prepackaged in "top".
				 */
				resid = 0;
				if (flags & MSG_EOR)
					top->m_flags |= M_EOR;
			} else do {
				sounlock(so);
				splx(s);
				if (top == NULL) {
					m = m_gethdr(M_WAIT, MT_DATA);
					mlen = MHLEN;
					m->m_pkthdr.len = 0;
					m->m_pkthdr.rcvif = NULL;
				} else {
					m = m_get(M_WAIT, MT_DATA);
					mlen = MLEN;
				}
				MCLAIM(m, so->so_snd.sb_mowner);
				if (sock_loan_thresh >= 0 &&
				    uio->uio_iov->iov_len >= sock_loan_thresh &&
				    space >= sock_loan_thresh &&
				    (len = sosend_loan(so, uio, m,
						       space)) != 0) {
					SOSEND_COUNTER_INCR(&sosend_loan_big);
					space -= len;
					goto have_data;
				}
				if (resid >= MINCLSIZE && space >= MCLBYTES) {
					SOSEND_COUNTER_INCR(&sosend_copy_big);
					m_clget(m, M_DONTWAIT);
					if ((m->m_flags & M_EXT) == 0)
						goto nopages;
					mlen = MCLBYTES;
					if (atomic && top == 0) {
						len = lmin(MCLBYTES - max_hdr,
						    resid);
						m->m_data += max_hdr;
					} else
						len = lmin(MCLBYTES, resid);
					space -= len;
				} else {
 nopages:
					SOSEND_COUNTER_INCR(&sosend_copy_small);
					len = lmin(lmin(mlen, resid), space);
					space -= len;
					/*
					 * For datagram protocols, leave room
					 * for protocol headers in first mbuf.
					 */
					if (atomic && top == 0 && len < mlen)
						MH_ALIGN(m, len);
				}
				error = uiomove(mtod(m, void *), (int)len, uio);
 have_data:
				resid = uio->uio_resid;
				m->m_len = len;
				*mp = m;
				top->m_pkthdr.len += len;
				s = splsoftnet();
				solock(so);
				if (error != 0)
					goto release;
				mp = &m->m_next;
				if (resid <= 0) {
					if (flags & MSG_EOR)
						top->m_flags |= M_EOR;
					break;
				}
			} while (space > 0 && atomic);

			if (so->so_state & SS_CANTSENDMORE) {
				error = EPIPE;
				goto release;
			}
			if (dontroute)
				so->so_options |= SO_DONTROUTE;
			if (resid > 0)
				so->so_state |= SS_MORETOCOME;
			error = (*so->so_proto->pr_usrreq)(so,
			    (flags & MSG_OOB) ? PRU_SENDOOB : PRU_SEND,
			    top, addr, control, curlwp);
			if (dontroute)
				so->so_options &= ~SO_DONTROUTE;
			if (resid > 0)
				so->so_state &= ~SS_MORETOCOME;
			clen = 0;
			control = NULL;
			top = NULL;
			mp = &top;
			if (error != 0)
				goto release;
		} while (resid && space > 0);
	} while (resid);

 release:
	sbunlock(&so->so_snd);
 out:
	sounlock(so);
	splx(s);
	if (top)
		m_freem(top);
	if (control)
		m_freem(control);
	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 void
sbsync(struct sockbuf *sb, struct mbuf *nextrecord)
{

	KASSERT(solocked(sb->sb_so));

	/*
	 * 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 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 avoid blocking network interrupts for the entire time here,
 * we splx() while doing the actual copy to user space.
 * 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 **mp0 for use in returning the chain.  The uio is then used
 * only for the count in uio_resid.
 */
int
soreceive(struct socket *so, struct mbuf **paddr, struct uio *uio,
	struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
{
	struct lwp *l = curlwp;
	struct mbuf	*m, **mp, *mt;
	int atomic, flags, len, error, s, offset, moff, type, orig_resid;
	const struct protosw	*pr;
	struct mbuf	*nextrecord;
	int		mbuf_removed = 0;
	const struct domain *dom;
	short		wakeup_state = 0;

	pr = so->so_proto;
	atomic = pr->pr_flags & PR_ATOMIC;
	dom = pr->pr_domain;
	mp = mp0;
	type = 0;
	orig_resid = uio->uio_resid;

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

	if (flags & MSG_OOB) {
		m = m_get(M_WAIT, MT_DATA);
		solock(so);
		error = (*pr->pr_usrreq)(so, PRU_RCVOOB, m,
		    (struct mbuf *)(long)(flags & MSG_PEEK), NULL, l);
		sounlock(so);
		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 > 0 && error == 0 && m);
 bad:
		if (m != NULL)
			m_freem(m);
		return error;
	}
	if (mp != NULL)
		*mp = NULL;

	/*
	 * solock() provides atomicity of access.  splsoftnet() prevents
	 * protocol processing soft interrupts from interrupting us and
	 * blocking (expensive).
	 */
	s = splsoftnet();
	solock(so);
	if (so->so_state & SS_ISCONFIRMING && uio->uio_resid)
		(*pr->pr_usrreq)(so, PRU_RCVD, NULL, NULL, NULL, l);

 restart:
	if ((error = sblock(&so->so_rcv, SBLOCKWAIT(flags))) != 0) {
		sounlock(so);
		splx(s);
		return error;
	}

	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,
	 *   2. MSG_WAITALL is set, and it is possible to do the entire
	 *	receive operation at once if we block (resid <= hiwat), or
	 *   3. MSG_DONTWAIT is not set.
	 * If MSG_WAITALL is set but resid is larger than the receive buffer,
	 * we have to do the receive in sections, and thus risk returning
	 * a short count if a timeout or signal occurs after we start.
	 */
	if (m == NULL ||
	    ((flags & MSG_DONTWAIT) == 0 &&
	     so->so_rcv.sb_cc < uio->uio_resid &&
	     (so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
	      ((flags & MSG_WAITALL) &&
	       uio->uio_resid <= so->so_rcv.sb_hiwat)) &&
	     m->m_nextpkt == NULL && !atomic)) {
#ifdef DIAGNOSTIC
		if (m == NULL && so->so_rcv.sb_cc)
			panic("receive 1");
#endif
		if (so->so_error) {
			if (m != NULL)
				goto dontblock;
			error = so->so_error;
			if ((flags & MSG_PEEK) == 0)
				so->so_error = 0;
			goto release;
		}
		if (so->so_state & SS_CANTRCVMORE) {
			if (m != NULL)
				goto dontblock;
			else
				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_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
		    (so->so_proto->pr_flags & PR_CONNREQUIRED)) {
			error = ENOTCONN;
			goto release;
		}
		if (uio->uio_resid == 0)
			goto release;
		if (so->so_nbio || (flags & MSG_DONTWAIT)) {
			error = EWOULDBLOCK;
			goto release;
		}
		SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 1");
		SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 1");
		sbunlock(&so->so_rcv);
		if (wakeup_state & SS_RESTARTSYS)
			error = ERESTART;
		else
			error = sbwait(&so->so_rcv);
		if (error != 0) {
			sounlock(so);
			splx(s);
			return error;
		}
		wakeup_state = so->so_state;
		goto restart;
	}
 dontblock:
	/*
	 * On entry here, m points to the first record of the socket buffer.
	 * 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 lock, 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.
	 */
	if (l != NULL)
		l->l_ru.ru_msgrcv++;
	KASSERT(m == so->so_rcv.sb_mb);
	SBLASTRECORDCHK(&so->so_rcv, "soreceive 1");
	SBLASTMBUFCHK(&so->so_rcv, "soreceive 1");
	nextrecord = m->m_nextpkt;
	if (pr->pr_flags & PR_ADDR) {
#ifdef DIAGNOSTIC
		if (m->m_type != MT_SONAME)
			panic("receive 1a");
#endif
		orig_resid = 0;
		if (flags & MSG_PEEK) {
			if (paddr)
				*paddr = m_copy(m, 0, m->m_len);
			m = m->m_next;
		} else {
			sbfree(&so->so_rcv, m);
			mbuf_removed = 1;
			if (paddr != NULL) {
				*paddr = m;
				so->so_rcv.sb_mb = m->m_next;
				m->m_next = NULL;
				m = so->so_rcv.sb_mb;
			} else {
				MFREE(m, so->so_rcv.sb_mb);
				m = so->so_rcv.sb_mb;
			}
			sbsync(&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 (__predict_false(m != NULL && m->m_type == MT_CONTROL)) {
		struct mbuf *cm = NULL, *cmn;
		struct mbuf **cme = &cm;

		do {
			if (flags & MSG_PEEK) {
				if (controlp != NULL) {
					*controlp = m_copy(m, 0, m->m_len);
					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)
			sbsync(&so->so_rcv, nextrecord);
		for (; cm != NULL; cm = cmn) {
			cmn = cm->m_next;
			cm->m_next = NULL;
			type = mtod(cm, struct cmsghdr *)->cmsg_type;
			if (controlp != NULL) {
				if (dom->dom_externalize != NULL &&
				    type == SCM_RIGHTS) {
					sounlock(so);
					splx(s);
					error = (*dom->dom_externalize)(cm, l,
					    (flags & MSG_CMSG_CLOEXEC) ?
					    O_CLOEXEC : 0);
					s = splsoftnet();
					solock(so);
				}
				*controlp = cm;
				while (*controlp != NULL)
					controlp = &(*controlp)->m_next;
			} else {
				/*
				 * Dispose of any SCM_RIGHTS message that went
				 * through the read path rather than recv.
				 */
				if (dom->dom_dispose != NULL &&
				    type == SCM_RIGHTS) {
				    	sounlock(so);
					(*dom->dom_dispose)(cm);
					solock(so);
				}
				m_freem(cm);
			}
		}
		if (m != NULL)
			nextrecord = so->so_rcv.sb_mb->m_nextpkt;
		else
			nextrecord = so->so_rcv.sb_mb;
		orig_resid = 0;
	}

	/* If m is non-NULL, we have some data to read. */
	if (__predict_true(m != NULL)) {
		type = m->m_type;
		if (type == MT_OOBDATA)
			flags |= MSG_OOB;
	}
	SBLASTRECORDCHK(&so->so_rcv, "soreceive 2");
	SBLASTMBUFCHK(&so->so_rcv, "soreceive 2");

	moff = 0;
	offset = 0;
	while (m != NULL && uio->uio_resid > 0 && error == 0) {
		if (m->m_type == MT_OOBDATA) {
			if (type != MT_OOBDATA)
				break;
		} else if (type == MT_OOBDATA)
			break;
#ifdef DIAGNOSTIC
		else if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
			panic("receive 3");
#endif
		so->so_state &= ~SS_RCVATMARK;
		wakeup_state = 0;
		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) {
			SBLASTRECORDCHK(&so->so_rcv, "soreceive uiomove");
			SBLASTMBUFCHK(&so->so_rcv, "soreceive uiomove");
			sounlock(so);
			splx(s);
			error = uiomove(mtod(m, char *) + moff, (int)len, uio);
			s = splsoftnet();
			solock(so);
			if (error != 0) {
				/*
				 * If any part of the record has been removed
				 * (such as the MT_SONAME mbuf, which will
				 * happen when PR_ADDR, and thus also
				 * PR_ATOMIC, is set), then drop the entire
				 * record to maintain the atomicity of the
				 * receive operation.
				 *
				 * This avoids a later panic("receive 1a")
				 * when compiled with DIAGNOSTIC.
				 */
				if (m && mbuf_removed && atomic)
					(void) sbdroprecord(&so->so_rcv);

				goto release;
			}
		} else
			uio->uio_resid -= len;
		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) {
					*mp = m;
					mp = &m->m_next;
					so->so_rcv.sb_mb = m = m->m_next;
					*mp = NULL;
				} else {
					MFREE(m, so->so_rcv.sb_mb);
					m = so->so_rcv.sb_mb;
				}
				/*
				 * If m != NULL, we also know that
				 * so->so_rcv.sb_mb != NULL.
				 */
				KASSERT(so->so_rcv.sb_mb == m);
				if (m) {
					m->m_nextpkt = nextrecord;
					if (nextrecord == NULL)
						so->so_rcv.sb_lastrecord = m;
				} else {
					so->so_rcv.sb_mb = nextrecord;
					SB_EMPTY_FIXUP(&so->so_rcv);
				}
				SBLASTRECORDCHK(&so->so_rcv, "soreceive 3");
				SBLASTMBUFCHK(&so->so_rcv, "soreceive 3");
			}
		} else if (flags & MSG_PEEK)
			moff += len;
		else {
			if (mp != NULL) {
				mt = m_copym(m, 0, len, M_NOWAIT);
				if (__predict_false(mt == NULL)) {
					sounlock(so);
					mt = m_copym(m, 0, len, M_WAIT);
					solock(so);
				}
				*mp = mt;
			}
			m->m_data += len;
			m->m_len -= len;
			so->so_rcv.sb_cc -= len;
		}
		if (so->so_oobmark) {
			if ((flags & MSG_PEEK) == 0) {
				so->so_oobmark -= len;
				if (so->so_oobmark == 0) {
					so->so_state |= SS_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) {
			if (so->so_error || so->so_state & SS_CANTRCVMORE)
				break;
			/*
			 * If we are peeking and the socket receive buffer is
			 * full, stop since we can't get more data to peek at.
			 */
			if ((flags & MSG_PEEK) && sbspace(&so->so_rcv) <= 0)
				break;
			/*
			 * If we've drained the socket buffer, tell the
			 * protocol in case it needs to do something to
			 * get it filled again.
			 */
			if ((pr->pr_flags & PR_WANTRCVD) && so->so_pcb)
				(*pr->pr_usrreq)(so, PRU_RCVD,
				    NULL, (struct mbuf *)(long)flags, NULL, l);
			SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 2");
			SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 2");
			if (wakeup_state & SS_RESTARTSYS)
				error = ERESTART;
			else
				error = sbwait(&so->so_rcv);
			if (error != 0) {
				sbunlock(&so->so_rcv);
				sounlock(so);
				splx(s);
				return 0;
			}
			if ((m = so->so_rcv.sb_mb) != NULL)
				nextrecord = m->m_nextpkt;
			wakeup_state = so->so_state;
		}
	}

	if (m && atomic) {
		flags |= MSG_TRUNC;
		if ((flags & MSG_PEEK) == 0)
			(void) sbdroprecord(&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, "soreceive 4");
		SBLASTMBUFCHK(&so->so_rcv, "soreceive 4");
		if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
			(*pr->pr_usrreq)(so, PRU_RCVD, NULL,
			    (struct mbuf *)(long)flags, NULL, l);
	}
	if (orig_resid == uio->uio_resid && orig_resid &&
	    (flags & MSG_EOR) == 0 && (so->so_state & SS_CANTRCVMORE) == 0) {
		sbunlock(&so->so_rcv);
		goto restart;
	}

	if (flagsp != NULL)
		*flagsp |= flags;
 release:
	sbunlock(&so->so_rcv);
	sounlock(so);
	splx(s);
	return error;
}

int
soshutdown(struct socket *so, int how)
{
	const struct protosw	*pr;
	int	error;

	KASSERT(solocked(so));

	pr = so->so_proto;
	if (!(how == SHUT_RD || how == SHUT_WR || how == SHUT_RDWR))
		return (EINVAL);

	if (how == SHUT_RD || how == SHUT_RDWR) {
		sorflush(so);
		error = 0;
	}
	if (how == SHUT_WR || how == SHUT_RDWR)
		error = (*pr->pr_usrreq)(so, PRU_SHUTDOWN, NULL,
		    NULL, NULL, NULL);

	return error;
}

void
sorestart(struct socket *so)
{
	/*
	 * An application has called close() on an fd on which another
	 * of its threads has called a socket system call.
	 * Mark this and wake everyone up, and code that would block again
	 * instead returns ERESTART.
	 * On system call re-entry the fd is validated and EBADF returned.
	 * Any other fd will block again on the 2nd syscall.
	 */
	solock(so);
	so->so_state |= SS_RESTARTSYS;
	cv_broadcast(&so->so_cv);
	cv_broadcast(&so->so_snd.sb_cv);
	cv_broadcast(&so->so_rcv.sb_cv);
	sounlock(so);
}

void
sorflush(struct socket *so)
{
	struct sockbuf	*sb, asb;
	const struct protosw	*pr;

	KASSERT(solocked(so));

	sb = &so->so_rcv;
	pr = so->so_proto;
	socantrcvmore(so);
	sb->sb_flags |= SB_NOINTR;
	(void )sblock(sb, M_WAITOK);
	sbunlock(sb);
	asb = *sb;
	/*
	 * Clear most of the sockbuf structure, but leave some of the
	 * fields valid.
	 */
	memset(&sb->sb_startzero, 0,
	    sizeof(*sb) - offsetof(struct sockbuf, sb_startzero));
	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose) {
		sounlock(so);
		(*pr->pr_domain->dom_dispose)(asb.sb_mb);
		solock(so);
	}
	sbrelease(&asb, so);
}

/*
 * internal set SOL_SOCKET options
 */
static int
sosetopt1(struct socket *so, const struct sockopt *sopt)
{
	int error = EINVAL, optval, opt;
	struct linger l;
	struct timeval tv;

	switch ((opt = sopt->sopt_name)) {

	case SO_ACCEPTFILTER:
		error = accept_filt_setopt(so, sopt);
		KASSERT(solocked(so));
		break;

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

	case SO_DEBUG:
	case SO_KEEPALIVE:
	case SO_DONTROUTE:
	case SO_USELOOPBACK:
	case SO_BROADCAST:
	case SO_REUSEADDR:
	case SO_REUSEPORT:
	case SO_OOBINLINE:
	case SO_TIMESTAMP:
#ifdef SO_OTIMESTAMP
	case SO_OTIMESTAMP:
#endif
		error = sockopt_getint(sopt, &optval);
		solock(so);
		if (error)
			break;
		if (optval)
			so->so_options |= opt;
		else
			so->so_options &= ~opt;
		break;

	case SO_SNDBUF:
	case SO_RCVBUF:
	case SO_SNDLOWAT:
	case SO_RCVLOWAT:
		error = sockopt_getint(sopt, &optval);
		solock(so);
		if (error)
			break;

		/*
		 * Values < 1 make no sense for any of these
		 * options, so disallow them.
		 */
		if (optval < 1) {
			error = EINVAL;
			break;
		}

		switch (opt) {
		case SO_SNDBUF:
			if (sbreserve(&so->so_snd, (u_long)optval, so) == 0) {
				error = ENOBUFS;
				break;
			}
			so->so_snd.sb_flags &= ~SB_AUTOSIZE;
			break;

		case SO_RCVBUF:
			if (sbreserve(&so->so_rcv, (u_long)optval, so) == 0) {
				error = ENOBUFS;
				break;
			}
			so->so_rcv.sb_flags &= ~SB_AUTOSIZE;
			break;

		/*
		 * Make sure the low-water is never greater than
		 * the high-water.
		 */
		case SO_SNDLOWAT:
			if (optval > so->so_snd.sb_hiwat)
				optval = so->so_snd.sb_hiwat;

			so->so_snd.sb_lowat = optval;
			break;

		case SO_RCVLOWAT:
			if (optval > so->so_rcv.sb_hiwat)
				optval = so->so_rcv.sb_hiwat;

			so->so_rcv.sb_lowat = optval;
			break;
		}
		break;

#ifdef COMPAT_50
	case SO_OSNDTIMEO:
	case SO_ORCVTIMEO: {
		struct timeval50 otv;
		error = sockopt_get(sopt, &otv, sizeof(otv));
		if (error) {
			solock(so);
			break;
		}
		timeval50_to_timeval(&otv, &tv);
		opt = opt == SO_OSNDTIMEO ? SO_SNDTIMEO : SO_RCVTIMEO;
		error = 0;
		/*FALLTHROUGH*/
	}
#endif /* COMPAT_50 */

	case SO_SNDTIMEO:
	case SO_RCVTIMEO:
		if (error)
			error = sockopt_get(sopt, &tv, sizeof(tv));
		solock(so);
		if (error)
			break;

		if (tv.tv_sec > (INT_MAX - tv.tv_usec / tick) / hz) {
			error = EDOM;
			break;
		}

		optval = tv.tv_sec * hz + tv.tv_usec / tick;
		if (optval == 0 && tv.tv_usec != 0)
			optval = 1;

		switch (opt) {
		case SO_SNDTIMEO:
			so->so_snd.sb_timeo = optval;
			break;
		case SO_RCVTIMEO:
			so->so_rcv.sb_timeo = optval;
			break;
		}
		break;

	default:
		solock(so);
		error = ENOPROTOOPT;
		break;
	}
	KASSERT(solocked(so));
	return error;
}

int
sosetopt(struct socket *so, struct sockopt *sopt)
{
	int error, prerr;

	if (sopt->sopt_level == SOL_SOCKET) {
		error = sosetopt1(so, sopt);
		KASSERT(solocked(so));
	} else {
		error = ENOPROTOOPT;
		solock(so);
	}

	if ((error == 0 || error == ENOPROTOOPT) &&
	    so->so_proto != NULL && so->so_proto->pr_ctloutput != NULL) {
		/* give the protocol stack a shot */
		prerr = (*so->so_proto->pr_ctloutput)(PRCO_SETOPT, so, sopt);
		if (prerr == 0)
			error = 0;
		else if (prerr != ENOPROTOOPT)
			error = prerr;
	}
	sounlock(so);
	return error;
}

/*
 * so_setsockopt() is a wrapper providing a sockopt structure for sosetopt()
 */
int
so_setsockopt(struct lwp *l, struct socket *so, int level, int name,
    const void *val, size_t valsize)
{
	struct sockopt sopt;
	int error;

	KASSERT(valsize == 0 || val != NULL);

	sockopt_init(&sopt, level, name, valsize);
	sockopt_set(&sopt, val, valsize);

	error = sosetopt(so, &sopt);

	sockopt_destroy(&sopt);

	return error;
}
 
/*
 * internal get SOL_SOCKET options
 */
static int
sogetopt1(struct socket *so, struct sockopt *sopt)
{
	int error, optval, opt;
	struct linger l;
	struct timeval tv;

	switch ((opt = sopt->sopt_name)) {

	case SO_ACCEPTFILTER:
		error = accept_filt_getopt(so, sopt);
		break;

	case SO_LINGER:
		l.l_onoff = (so->so_options & SO_LINGER) ? 1 : 0;
		l.l_linger = so->so_linger;

		error = sockopt_set(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_BROADCAST:
	case SO_OOBINLINE:
	case SO_TIMESTAMP:
#ifdef SO_OTIMESTAMP
	case SO_OTIMESTAMP:
#endif
		error = sockopt_setint(sopt, (so->so_options & opt) ? 1 : 0);
		break;

	case SO_TYPE:
		error = sockopt_setint(sopt, so->so_type);
		break;

	case SO_ERROR:
		error = sockopt_setint(sopt, so->so_error);
		so->so_error = 0;
		break;

	case SO_SNDBUF:
		error = sockopt_setint(sopt, so->so_snd.sb_hiwat);
		break;

	case SO_RCVBUF:
		error = sockopt_setint(sopt, so->so_rcv.sb_hiwat);
		break;

	case SO_SNDLOWAT:
		error = sockopt_setint(sopt, so->so_snd.sb_lowat);
		break;

	case SO_RCVLOWAT:
		error = sockopt_setint(sopt, so->so_rcv.sb_lowat);
		break;

#ifdef COMPAT_50
	case SO_OSNDTIMEO:
	case SO_ORCVTIMEO: {
		struct timeval50 otv;

		optval = (opt == SO_OSNDTIMEO ?
		     so->so_snd.sb_timeo : so->so_rcv.sb_timeo);

		otv.tv_sec = optval / hz;
		otv.tv_usec = (optval % hz) * tick;

		error = sockopt_set(sopt, &otv, sizeof(otv));
		break;
	}
#endif /* COMPAT_50 */

	case SO_SNDTIMEO:
	case SO_RCVTIMEO:
		optval = (opt == SO_SNDTIMEO ?
		     so->so_snd.sb_timeo : so->so_rcv.sb_timeo);

		tv.tv_sec = optval / hz;
		tv.tv_usec = (optval % hz) * tick;

		error = sockopt_set(sopt, &tv, sizeof(tv));
		break;

	case SO_OVERFLOWED:
		error = sockopt_setint(sopt, so->so_rcv.sb_overflowed);
		break;

	default:
		error = ENOPROTOOPT;
		break;
	}

	return (error);
}

int
sogetopt(struct socket *so, struct sockopt *sopt)
{
	int		error;

	solock(so);
	if (sopt->sopt_level != SOL_SOCKET) {
		if (so->so_proto && so->so_proto->pr_ctloutput) {
			error = ((*so->so_proto->pr_ctloutput)
			    (PRCO_GETOPT, so, sopt));
		} else
			error = (ENOPROTOOPT);
	} else {
		error = sogetopt1(so, sopt);
	}
	sounlock(so);
	return (error);
}

/*
 * alloc sockopt data buffer buffer
 *	- will be released at destroy
 */
static int
sockopt_alloc(struct sockopt *sopt, size_t len, km_flag_t kmflag)
{

	KASSERT(sopt->sopt_size == 0);

	if (len > sizeof(sopt->sopt_buf)) {
		sopt->sopt_data = kmem_zalloc(len, kmflag);
		if (sopt->sopt_data == NULL)
			return ENOMEM;
	} else
		sopt->sopt_data = sopt->sopt_buf;

	sopt->sopt_size = len;
	return 0;
}

/*
 * initialise sockopt storage
 *	- MAY sleep during allocation
 */
void
sockopt_init(struct sockopt *sopt, int level, int name, size_t size)
{

	memset(sopt, 0, sizeof(*sopt));

	sopt->sopt_level = level;
	sopt->sopt_name = name;
	(void)sockopt_alloc(sopt, size, KM_SLEEP);
}

/*
 * destroy sockopt storage
 *	- will release any held memory references
 */
void
sockopt_destroy(struct sockopt *sopt)
{

	if (sopt->sopt_data != sopt->sopt_buf)
		kmem_free(sopt->sopt_data, sopt->sopt_size);

	memset(sopt, 0, sizeof(*sopt));
}

/*
 * set sockopt value
 *	- value is copied into sockopt
 * 	- memory is allocated when necessary, will not sleep
 */
int
sockopt_set(struct sockopt *sopt, const void *buf, size_t len)
{
	int error;

	if (sopt->sopt_size == 0) {
		error = sockopt_alloc(sopt, len, KM_NOSLEEP);
		if (error)
			return error;
	}

	KASSERT(sopt->sopt_size == len);
	memcpy(sopt->sopt_data, buf, len);
	return 0;
}

/*
 * common case of set sockopt integer value
 */
int
sockopt_setint(struct sockopt *sopt, int val)
{

	return sockopt_set(sopt, &val, sizeof(int));
}

/*
 * get sockopt value
 *	- correct size must be given
 */
int
sockopt_get(const struct sockopt *sopt, void *buf, size_t len)
{

	if (sopt->sopt_size != len)
		return EINVAL;

	memcpy(buf, sopt->sopt_data, len);
	return 0;
}

/*
 * common case of get sockopt integer value
 */
int
sockopt_getint(const struct sockopt *sopt, int *valp)
{

	return sockopt_get(sopt, valp, sizeof(int));
}

/*
 * set sockopt value from mbuf
 *	- ONLY for legacy code
 *	- mbuf is released by sockopt
 *	- will not sleep
 */
int
sockopt_setmbuf(struct sockopt *sopt, struct mbuf *m)
{
	size_t len;
	int error;

	len = m_length(m);

	if (sopt->sopt_size == 0) {
		error = sockopt_alloc(sopt, len, KM_NOSLEEP);
		if (error)
			return error;
	}

	KASSERT(sopt->sopt_size == len);
	m_copydata(m, 0, len, sopt->sopt_data);
	m_freem(m);

	return 0;
}

/*
 * get sockopt value into mbuf
 *	- ONLY for legacy code
 *	- mbuf to be released by the caller
 *	- will not sleep
 */
struct mbuf *
sockopt_getmbuf(const struct sockopt *sopt)
{
	struct mbuf *m;

	if (sopt->sopt_size > MCLBYTES)
		return NULL;

	m = m_get(M_DONTWAIT, MT_SOOPTS);
	if (m == NULL)
		return NULL;

	if (sopt->sopt_size > MLEN) {
		MCLGET(m, M_DONTWAIT);
		if ((m->m_flags & M_EXT) == 0) {
			m_free(m);
			return NULL;
		}
	}

	memcpy(mtod(m, void *), sopt->sopt_data, sopt->sopt_size);
	m->m_len = sopt->sopt_size;

	return m;
}

void
sohasoutofband(struct socket *so)
{

	fownsignal(so->so_pgid, SIGURG, POLL_PRI, POLLPRI|POLLRDBAND, so);
	selnotify(&so->so_rcv.sb_sel, POLLPRI | POLLRDBAND, NOTE_SUBMIT);
}

static void
filt_sordetach(struct knote *kn)
{
	struct socket	*so;

	so = ((file_t *)kn->kn_obj)->f_data;
	solock(so);
	SLIST_REMOVE(&so->so_rcv.sb_sel.sel_klist, kn, knote, kn_selnext);
	if (SLIST_EMPTY(&so->so_rcv.sb_sel.sel_klist))
		so->so_rcv.sb_flags &= ~SB_KNOTE;
	sounlock(so);
}

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

	so = ((file_t *)kn->kn_obj)->f_data;
	if (hint != NOTE_SUBMIT)
		solock(so);
	kn->kn_data = so->so_rcv.sb_cc;
	if (so->so_state & SS_CANTRCVMORE) {
		kn->kn_flags |= EV_EOF;
		kn->kn_fflags = so->so_error;
		rv = 1;
	} else if (so->so_error)	/* temporary udp error */
		rv = 1;
	else if (kn->kn_sfflags & NOTE_LOWAT)
		rv = (kn->kn_data >= kn->kn_sdata);
	else 
		rv = (kn->kn_data >= so->so_rcv.sb_lowat);
	if (hint != NOTE_SUBMIT)
		sounlock(so);
	return rv;
}

static void
filt_sowdetach(struct knote *kn)
{
	struct socket	*so;

	so = ((file_t *)kn->kn_obj)->f_data;
	solock(so);
	SLIST_REMOVE(&so->so_snd.sb_sel.sel_klist, kn, knote, kn_selnext);
	if (SLIST_EMPTY(&so->so_snd.sb_sel.sel_klist))
		so->so_snd.sb_flags &= ~SB_KNOTE;
	sounlock(so);
}

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

	so = ((file_t *)kn->kn_obj)->f_data;
	if (hint != NOTE_SUBMIT)
		solock(so);
	kn->kn_data = sbspace(&so->so_snd);
	if (so->so_state & SS_CANTSENDMORE) {
		kn->kn_flags |= EV_EOF;
		kn->kn_fflags = so->so_error;
		rv = 1;
	} else if (so->so_error)	/* temporary udp error */
		rv = 1;
	else if (((so->so_state & SS_ISCONNECTED) == 0) &&
	    (so->so_proto->pr_flags & PR_CONNREQUIRED))
		rv = 0;
	else if (kn->kn_sfflags & NOTE_LOWAT)
		rv = (kn->kn_data >= kn->kn_sdata);
	else
		rv = (kn->kn_data >= so->so_snd.sb_lowat);
	if (hint != NOTE_SUBMIT)
		sounlock(so);
	return rv;
}

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

	so = ((file_t *)kn->kn_obj)->f_data;

	/*
	 * Set kn_data to number of incoming connections, not
	 * counting partial (incomplete) connections.
	 */
	if (hint != NOTE_SUBMIT)
		solock(so);
	kn->kn_data = so->so_qlen;
	rv = (kn->kn_data > 0);
	if (hint != NOTE_SUBMIT)
		sounlock(so);
	return rv;
}

static const struct filterops solisten_filtops =
	{ 1, NULL, filt_sordetach, filt_solisten };
static const struct filterops soread_filtops =
	{ 1, NULL, filt_sordetach, filt_soread };
static const struct filterops sowrite_filtops =
	{ 1, NULL, filt_sowdetach, filt_sowrite };

int
soo_kqfilter(struct file *fp, struct knote *kn)
{
	struct socket	*so;
	struct sockbuf	*sb;

	so = ((file_t *)kn->kn_obj)->f_data;
	solock(so);
	switch (kn->kn_filter) {
	case EVFILT_READ:
		if (so->so_options & SO_ACCEPTCONN)
			kn->kn_fop = &solisten_filtops;
		else
			kn->kn_fop = &soread_filtops;
		sb = &so->so_rcv;
		break;
	case EVFILT_WRITE:
		kn->kn_fop = &sowrite_filtops;
		sb = &so->so_snd;
		break;
	default:
		sounlock(so);
		return (EINVAL);
	}
	SLIST_INSERT_HEAD(&sb->sb_sel.sel_klist, kn, kn_selnext);
	sb->sb_flags |= SB_KNOTE;
	sounlock(so);
	return (0);
}

static int
sodopoll(struct socket *so, int events)
{
	int revents;

	revents = 0;

	if (events & (POLLIN | POLLRDNORM))
		if (soreadable(so))
			revents |= events & (POLLIN | POLLRDNORM);

	if (events & (POLLOUT | POLLWRNORM))
		if (sowritable(so))
			revents |= events & (POLLOUT | POLLWRNORM);

	if (events & (POLLPRI | POLLRDBAND))
		if (so->so_oobmark || (so->so_state & SS_RCVATMARK))
			revents |= events & (POLLPRI | POLLRDBAND);

	return revents;
}

int
sopoll(struct socket *so, int events)
{
	int revents = 0;

#ifndef DIAGNOSTIC
	/*
	 * Do a quick, unlocked check in expectation that the socket
	 * will be ready for I/O.  Don't do this check if DIAGNOSTIC,
	 * as the solocked() assertions will fail.
	 */
	if ((revents = sodopoll(so, events)) != 0)
		return revents;
#endif

	solock(so);
	if ((revents = sodopoll(so, events)) == 0) {
		if (events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
			selrecord(curlwp, &so->so_rcv.sb_sel);
			so->so_rcv.sb_flags |= SB_NOTIFY;
		}

		if (events & (POLLOUT | POLLWRNORM)) {
			selrecord(curlwp, &so->so_snd.sb_sel);
			so->so_snd.sb_flags |= SB_NOTIFY;
		}
	}
	sounlock(so);

	return revents;
}


#include <sys/sysctl.h>

static int sysctl_kern_somaxkva(SYSCTLFN_PROTO);

/*
 * sysctl helper routine for kern.somaxkva.  ensures that the given
 * value is not too small.
 * (XXX should we maybe make sure it's not too large as well?)
 */
static int
sysctl_kern_somaxkva(SYSCTLFN_ARGS)
{
	int error, new_somaxkva;
	struct sysctlnode node;

	new_somaxkva = somaxkva;
	node = *rnode;
	node.sysctl_data = &new_somaxkva;
	error = sysctl_lookup(SYSCTLFN_CALL(&node));
	if (error || newp == NULL)
		return (error);

	if (new_somaxkva < (16 * 1024 * 1024)) /* sanity */
		return (EINVAL);

	mutex_enter(&so_pendfree_lock);
	somaxkva = new_somaxkva;
	cv_broadcast(&socurkva_cv);
	mutex_exit(&so_pendfree_lock);

	return (error);
}

static void
sysctl_kern_somaxkva_setup(void)
{

	KASSERT(socket_sysctllog == NULL);
	sysctl_createv(&socket_sysctllog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_NODE, "kern", NULL,
		       NULL, 0, NULL, 0,
		       CTL_KERN, CTL_EOL);

	sysctl_createv(&socket_sysctllog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "somaxkva",
		       SYSCTL_DESCR("Maximum amount of kernel memory to be "
				    "used for socket buffers"),
		       sysctl_kern_somaxkva, 0, NULL, 0,
		       CTL_KERN, KERN_SOMAXKVA, CTL_EOL);
}