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

Revision 1.98, Sat Apr 17 15:15:29 2004 UTC (10 years, 8 months ago) by christos
Branch: MAIN
Changes since 1.97: +25 -9 lines

PR/9347: Eric E. Fair: socket buffer pool exhaustion leads to system deadlock
and unkillable processes.
1. Introduce new SBSIZE resource limit from FreeBSD to limit socket buffer
   size resource.
2. make sokvareserve interruptible, so processes ltsleeping on it can be
   killed.

/*	$NetBSD: uipc_socket.c,v 1.98 2004/04/17 15:15:29 christos Exp $	*/

/*-
 * Copyright (c) 2002 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.
 *
 * 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 NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 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) 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 1.98 2004/04/17 15:15:29 christos Exp $");

#include "opt_sock_counters.h"
#include "opt_sosend_loan.h"
#include "opt_mbuftrace.h"
#include "opt_somaxkva.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/malloc.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/pool.h>
#include <sys/event.h>
#include <sys/poll.h>

#include <uvm/uvm.h>

struct pool	socket_pool;

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

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

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

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

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

#else

#define	SOSEND_COUNTER_INCR(ev)		/* nothing */

#endif /* SOSEND_COUNTERS */

void
soinit(void)
{

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

	pool_init(&socket_pool, sizeof(struct socket), 0, 0, 0,
	    "sockpl", NULL);

#ifdef SOSEND_COUNTERS
	evcnt_attach_static(&sosend_loan_big);
	evcnt_attach_static(&sosend_copy_big);
	evcnt_attach_static(&sosend_copy_small);
	evcnt_attach_static(&sosend_kvalimit);
#endif /* SOSEND_COUNTERS */
}

#ifdef SOSEND_NO_LOAN
int use_sosend_loan = 0;
#else
int use_sosend_loan = 1;
#endif

struct simplelock so_pendfree_slock = SIMPLELOCK_INITIALIZER;
struct mbuf *so_pendfree;

#ifndef SOMAXKVA
#define	SOMAXKVA (16 * 1024 * 1024)
#endif
int somaxkva = SOMAXKVA;
int socurkva;
int sokvawaiters;

#define	SOCK_LOAN_THRESH	4096
#define	SOCK_LOAN_CHUNK		65536

static size_t sodopendfree(struct socket *);
static size_t sodopendfreel(struct socket *);
static __inline vsize_t sokvareserve(struct socket *, vsize_t);
static __inline void sokvaunreserve(vsize_t);

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

	s = splvm();
	simple_lock(&so_pendfree_slock);
	while (socurkva + len > somaxkva) {
		size_t freed;

		/*
		 * try to do pendfree.
		 */

		freed = sodopendfreel(so);

		/*
		 * if some kva was freed, try again.
		 */

		if (freed)
			continue;

		SOSEND_COUNTER_INCR(&sosend_kvalimit);
		sokvawaiters++;
		error = ltsleep(&socurkva, PVM | PCATCH, "sokva", 0,
		    &so_pendfree_slock);
		sokvawaiters--;
		if (error) {
			len = 0;
			break;
		}
	}
	socurkva += len;
	simple_unlock(&so_pendfree_slock);
	splx(s);
	return len;
}

static __inline void
sokvaunreserve(vsize_t len)
{
	int s;

	s = splvm();
	simple_lock(&so_pendfree_slock);
	socurkva -= len;
	if (sokvawaiters)
		wakeup(&socurkva);
	simple_unlock(&so_pendfree_slock);
	splx(s);
}

/*
 * 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_valloc_wait(kernel_map, len);
	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);

	/*
	 * unreserve kva.
	 */

	sokvaunreserve(len);
}

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

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

	if (__predict_false(pgs == NULL)) {
		pgs = alloca(npgs * sizeof(*pgs));

		for (i = 0, va = sva; va < eva; i++, va += PAGE_SIZE) {
			if (pmap_extract(pmap_kernel(), va, &pa) == FALSE)
				panic("sodoloanfree: va 0x%lx not mapped", va);
			pgs[i] = PHYS_TO_VM_PAGE(pa);
		}
	}

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

static size_t
sodopendfree(struct socket *so)
{
	int s;
	size_t rv;

	s = splvm();
	simple_lock(&so_pendfree_slock);
	rv = sodopendfreel(so);
	simple_unlock(&so_pendfree_slock);
	splx(s);

	return rv;
}

/*
 * sodopendfreel: free mbufs on "pendfree" list.
 * unlock and relock so_pendfree_slock when freeing mbufs.
 *
 * => called with so_pendfree_slock held.
 * => called at splvm.
 */

static size_t
sodopendfreel(struct socket *so)
{
	size_t rv = 0;

	LOCK_ASSERT(simple_lock_held(&so_pendfree_slock));

	for (;;) {
		struct mbuf *m;
		struct mbuf *next;

		m = so_pendfree;
		if (m == NULL)
			break;
		so_pendfree = NULL;
		simple_unlock(&so_pendfree_slock);
		/* XXX splx */

		for (; m != NULL; m = next) {
			next = m->m_next;

			rv += m->m_ext.ext_size;
			sodoloanfree((m->m_flags & M_EXT_PAGES) ?
			    m->m_ext.ext_pgs : NULL, m->m_ext.ext_buf,
			    m->m_ext.ext_size);
			pool_cache_put(&mbpool_cache, m);
		}

		/* XXX splvm */
		simple_lock(&so_pendfree_slock);
	}

	return (rv);
}

void
soloanfree(struct mbuf *m, caddr_t buf, size_t size, void *arg)
{
	int s;

	if (m == NULL) {

		/*
		 * called from MEXTREMOVE.
		 */

		sodoloanfree(NULL, buf, size);
		return;
	}

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

	s = splvm();
	simple_lock(&so_pendfree_slock);
	m->m_next = so_pendfree;
	so_pendfree = m;
	if (sokvawaiters)
		wakeup(&socurkva);
	simple_unlock(&so_pendfree_slock);
	splx(s);
}

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, va;
	int npgs, i, error;

	if (uio->uio_segflg != UIO_USERSPACE)
		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;

	/* XXX KDASSERT */
	KASSERT(npgs <= M_EXT_MAXPAGES);

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

	error = uvm_loan(&uio->uio_procp->p_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);
	pmap_update(pmap_kernel());

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

	MEXTADD(m, (caddr_t) 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 = (caddr_t) 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);
}

/*
 * 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 proc	*p;
	struct protosw	*prp;
	struct socket	*so;
	int		error, s;

	p = curproc;		/* XXX */
	if (proto)
		prp = pffindproto(dom, proto, type);
	else
		prp = pffindtype(dom, type);
	if (prp == 0 || prp->pr_usrreq == 0)
		return (EPROTONOSUPPORT);
	if (prp->pr_type != type)
		return (EPROTOTYPE);
	s = splsoftnet();
	so = pool_get(&socket_pool, PR_WAITOK);
	memset((caddr_t)so, 0, sizeof(*so));
	TAILQ_INIT(&so->so_q0);
	TAILQ_INIT(&so->so_q);
	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
	if (p != 0)
		so->so_uid = p->p_ucred->cr_uid;
	else
		so->so_uid = UID_MAX;
	error = (*prp->pr_usrreq)(so, PRU_ATTACH, (struct mbuf *)0,
	    (struct mbuf *)(long)proto, (struct mbuf *)0, p);
	if (error) {
		so->so_state |= SS_NOFDREF;
		sofree(so);
		splx(s);
		return (error);
	}
	splx(s);
	*aso = so;
	return (0);
}

int
sobind(struct socket *so, struct mbuf *nam, struct proc *p)
{
	int	s, error;

	s = splsoftnet();
	error = (*so->so_proto->pr_usrreq)(so, PRU_BIND, (struct mbuf *)0,
	    nam, (struct mbuf *)0, p);
	splx(s);
	return (error);
}

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

	s = splsoftnet();
	error = (*so->so_proto->pr_usrreq)(so, PRU_LISTEN, (struct mbuf *)0,
	    (struct mbuf *)0, (struct mbuf *)0, (struct proc *)0);
	if (error) {
		splx(s);
		return (error);
	}
	if (TAILQ_EMPTY(&so->so_q))
		so->so_options |= SO_ACCEPTCONN;
	if (backlog < 0)
		backlog = 0;
	so->so_qlimit = min(backlog, somaxconn);
	splx(s);
	return (0);
}

void
sofree(struct socket *so)
{

	if (so->so_pcb || (so->so_state & SS_NOFDREF) == 0)
		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))
			return;
	}
	if (so->so_rcv.sb_hiwat)
		(void)chgsbsize(so->so_uid, &so->so_rcv.sb_hiwat, 0,
		    RLIM_INFINITY);
	if (so->so_snd.sb_hiwat)
		(void)chgsbsize(so->so_uid, &so->so_snd.sb_hiwat, 0,
		    RLIM_INFINITY);
	sbrelease(&so->so_snd, so);
	sorflush(so);
	pool_put(&socket_pool, 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		s, error;

	error = 0;
	s = splsoftnet();		/* conservative */
	if (so->so_options & SO_ACCEPTCONN) {
		while ((so2 = TAILQ_FIRST(&so->so_q0)) != 0) {
			(void) soqremque(so2, 0);
			(void) soabort(so2);
		}
		while ((so2 = TAILQ_FIRST(&so->so_q)) != 0) {
			(void) soqremque(so2, 1);
			(void) soabort(so2);
		}
	}
	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_state & SS_NBIO))
				goto drop;
			while (so->so_state & SS_ISCONNECTED) {
				error = tsleep((caddr_t)&so->so_timeo,
					       PSOCK | PCATCH, netcls,
					       so->so_linger * hz);
				if (error)
					break;
			}
		}
	}
 drop:
	if (so->so_pcb) {
		int error2 = (*so->so_proto->pr_usrreq)(so, PRU_DETACH,
		    (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0,
		    (struct proc *)0);
		if (error == 0)
			error = error2;
	}
 discard:
	if (so->so_state & SS_NOFDREF)
		panic("soclose: NOFDREF");
	so->so_state |= SS_NOFDREF;
	sofree(so);
	splx(s);
	return (error);
}

/*
 * Must be called at splsoftnet...
 */
int
soabort(struct socket *so)
{

	return (*so->so_proto->pr_usrreq)(so, PRU_ABORT, (struct mbuf *)0,
	    (struct mbuf *)0, (struct mbuf *)0, (struct proc *)0);
}

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

	error = 0;
	s = splsoftnet();
	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,
		    (struct mbuf *)0, nam, (struct mbuf *)0, (struct proc *)0);
	else
		error = ECONNABORTED;

	splx(s);
	return (error);
}

int
soconnect(struct socket *so, struct mbuf *nam)
{
	struct proc	*p;
	int		s, error;

	p = curproc;		/* XXX */
	if (so->so_options & SO_ACCEPTCONN)
		return (EOPNOTSUPP);
	s = splsoftnet();
	/*
	 * 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,
		    (struct mbuf *)0, nam, (struct mbuf *)0, p);
	splx(s);
	return (error);
}

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

	s = splsoftnet();
	error = (*so1->so_proto->pr_usrreq)(so1, PRU_CONNECT2,
	    (struct mbuf *)0, (struct mbuf *)so2, (struct mbuf *)0,
	    (struct proc *)0);
	splx(s);
	return (error);
}

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

	s = splsoftnet();
	if ((so->so_state & SS_ISCONNECTED) == 0) {
		error = ENOTCONN;
		goto bad;
	}
	if (so->so_state & SS_ISDISCONNECTING) {
		error = EALREADY;
		goto bad;
	}
	error = (*so->so_proto->pr_usrreq)(so, PRU_DISCONNECT,
	    (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0,
	    (struct proc *)0);
 bad:
	splx(s);
	sodopendfree(so);
	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 proc	*p;
	struct mbuf	**mp, *m;
	long		space, len, resid, clen, mlen;
	int		error, s, dontroute, atomic;

	sodopendfree(so);

	p = curproc;		/* XXX */
	clen = 0;
	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);
	p->p_stats->p_ru.ru_msgsnd++;
	if (control)
		clen = control->m_len;
#define	snderr(errno)	{ error = errno; splx(s); goto release; }

 restart:
	if ((error = sblock(&so->so_snd, SBLOCKWAIT(flags))) != 0)
		goto out;
	do {
		s = splsoftnet();
		if (so->so_state & SS_CANTSENDMORE)
			snderr(EPIPE);
		if (so->so_error) {
			error = so->so_error;
			so->so_error = 0;
			splx(s);
			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))
					snderr(ENOTCONN);
			} else if (addr == 0)
				snderr(EDESTADDRREQ);
		}
		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)
			snderr(EMSGSIZE);
		if (space < resid + clen &&
		    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
			if (so->so_state & SS_NBIO)
				snderr(EWOULDBLOCK);
			sbunlock(&so->so_snd);
			error = sbwait(&so->so_snd);
			splx(s);
			if (error)
				goto out;
			goto restart;
		}
		splx(s);
		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 {
				if (top == 0) {
					m = m_gethdr(M_WAIT, MT_DATA);
					mlen = MHLEN;
					m->m_pkthdr.len = 0;
					m->m_pkthdr.rcvif = (struct ifnet *)0;
				} else {
					m = m_get(M_WAIT, MT_DATA);
					mlen = MLEN;
				}
				MCLAIM(m, so->so_snd.sb_mowner);
				if (use_sosend_loan &&
				    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_WAIT);
					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, caddr_t), (int)len,
				    uio);
 have_data:
				resid = uio->uio_resid;
				m->m_len = len;
				*mp = m;
				top->m_pkthdr.len += len;
				if (error)
					goto release;
				mp = &m->m_next;
				if (resid <= 0) {
					if (flags & MSG_EOR)
						top->m_flags |= M_EOR;
					break;
				}
			} while (space > 0 && atomic);
			
			s = splsoftnet();

			if (so->so_state & SS_CANTSENDMORE)
				snderr(EPIPE);

			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, p);
			if (dontroute)
				so->so_options &= ~SO_DONTROUTE;
			if (resid > 0)
				so->so_state &= ~SS_MORETOCOME;
			splx(s);

			clen = 0;
			control = 0;
			top = 0;
			mp = &top;
			if (error)
				goto release;
		} while (resid && space > 0);
	} while (resid);

 release:
	sbunlock(&so->so_snd);
 out:
	if (top)
		m_freem(top);
	if (control)
		m_freem(control);
	return (error);
}

/*
 * 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 mbuf	*m, **mp;
	int		flags, len, error, s, offset, moff, type, orig_resid;
	struct protosw	*pr;
	struct mbuf	*nextrecord;
	int		mbuf_removed = 0;

	pr = so->so_proto;
	mp = mp0;
	type = 0;
	orig_resid = uio->uio_resid;
	if (paddr)
		*paddr = 0;
	if (controlp)
		*controlp = 0;
	if (flagsp)
		flags = *flagsp &~ MSG_EOR;
	else
		flags = 0;

	if ((flags & MSG_DONTWAIT) == 0)
		sodopendfree(so);

	if (flags & MSG_OOB) {
		m = m_get(M_WAIT, MT_DATA);
		error = (*pr->pr_usrreq)(so, PRU_RCVOOB, m,
		    (struct mbuf *)(long)(flags & MSG_PEEK), (struct mbuf *)0,
		    (struct proc *)0);
		if (error)
			goto bad;
		do {
			error = uiomove(mtod(m, caddr_t),
			    (int) min(uio->uio_resid, m->m_len), uio);
			m = m_free(m);
		} while (uio->uio_resid && error == 0 && m);
 bad:
		if (m)
			m_freem(m);
		return (error);
	}
	if (mp)
		*mp = (struct mbuf *)0;
	if (so->so_state & SS_ISCONFIRMING && uio->uio_resid)
		(*pr->pr_usrreq)(so, PRU_RCVD, (struct mbuf *)0,
		    (struct mbuf *)0, (struct mbuf *)0, (struct proc *)0);

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

	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 == 0 || (((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 == 0 && (pr->pr_flags & PR_ATOMIC) == 0)) {
#ifdef DIAGNOSTIC
		if (m == 0 && so->so_rcv.sb_cc)
			panic("receive 1");
#endif
		if (so->so_error) {
			if (m)
				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)
				goto dontblock;
			else
				goto release;
		}
		for (; m; 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_state & SS_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);
		error = sbwait(&so->so_rcv);
		splx(s);
		if (error)
			return (error);
		goto restart;
	}
 dontblock:
	/*
	 * On entry here, m points to the first record of the socket buffer.
	 * While we process the initial mbufs containing address and control
	 * info, we save a copy of m->m_nextpkt into nextrecord.
	 */
#ifdef notyet /* XXXX */
	if (uio->uio_procp)
		uio->uio_procp->p_stats->p_ru.ru_msgrcv++;
#endif
	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) {
				*paddr = m;
				so->so_rcv.sb_mb = m->m_next;
				m->m_next = 0;
				m = so->so_rcv.sb_mb;
			} else {
				MFREE(m, so->so_rcv.sb_mb);
				m = so->so_rcv.sb_mb;
			}
		}
	}
	while (m && m->m_type == MT_CONTROL && error == 0) {
		if (flags & MSG_PEEK) {
			if (controlp)
				*controlp = m_copy(m, 0, m->m_len);
			m = m->m_next;
		} else {
			sbfree(&so->so_rcv, m);
			mbuf_removed = 1;
			if (controlp) {
				if (pr->pr_domain->dom_externalize &&
				    mtod(m, struct cmsghdr *)->cmsg_type ==
				    SCM_RIGHTS)
					error = (*pr->pr_domain->dom_externalize)(m);
				*controlp = m;
				so->so_rcv.sb_mb = m->m_next;
				m->m_next = 0;
				m = so->so_rcv.sb_mb;
			} else {
				MFREE(m, so->so_rcv.sb_mb);
				m = so->so_rcv.sb_mb;
			}
		}
		if (controlp) {
			orig_resid = 0;
			controlp = &(*controlp)->m_next;
		}
	}

	/*
	 * If m is non-NULL, we have some data to read.  From now on,
	 * make sure to keep sb_lastrecord consistent when working on
	 * the last packet on the chain (nextrecord == NULL) and we
	 * change m->m_nextpkt.
	 */
	if (m) {
		if ((flags & MSG_PEEK) == 0) {
			m->m_nextpkt = nextrecord;
			/*
			 * If nextrecord == NULL (this is a single chain),
			 * then sb_lastrecord may not be valid here if m
			 * was changed earlier.
			 */
			if (nextrecord == NULL) {
				KASSERT(so->so_rcv.sb_mb == m);
				so->so_rcv.sb_lastrecord = m;
			}
		}
		type = m->m_type;
		if (type == MT_OOBDATA)
			flags |= MSG_OOB;
	} else {
		if ((flags & MSG_PEEK) == 0) {
			KASSERT(so->so_rcv.sb_mb == m);
			so->so_rcv.sb_mb = nextrecord;
			SB_EMPTY_FIXUP(&so->so_rcv);
		}
	}
	SBLASTRECORDCHK(&so->so_rcv, "soreceive 2");
	SBLASTMBUFCHK(&so->so_rcv, "soreceive 2");

	moff = 0;
	offset = 0;
	while (m && 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;
		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 == 0) {
			SBLASTRECORDCHK(&so->so_rcv, "soreceive uiomove");
			SBLASTMBUFCHK(&so->so_rcv, "soreceive uiomove");
			splx(s);
			error = uiomove(mtod(m, caddr_t) + moff, (int)len, uio);
			s = splsoftnet();
			if (error) {
				/*
				 * 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
				    && (pr->pr_flags & PR_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 = (struct mbuf *)0;
				} 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)
					*mp = m_copym(m, 0, len, M_WAIT);
				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 == 0 && 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,
				    (struct mbuf *)0,
				    (struct mbuf *)(long)flags,
				    (struct mbuf *)0,
				    (struct proc *)0);
			SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 2");
			SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 2");
			error = sbwait(&so->so_rcv);
			if (error) {
				sbunlock(&so->so_rcv);
				splx(s);
				return (0);
			}
			if ((m = so->so_rcv.sb_mb) != NULL)
				nextrecord = m->m_nextpkt;
		}
	}

	if (m && pr->pr_flags & PR_ATOMIC) {
		flags |= MSG_TRUNC;
		if ((flags & MSG_PEEK) == 0)
			(void) sbdroprecord(&so->so_rcv);
	}
	if ((flags & MSG_PEEK) == 0) {
		if (m == 0) {
			/*
			 * 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, (struct mbuf *)0,
			    (struct mbuf *)(long)flags, (struct mbuf *)0,
			    (struct proc *)0);
	}
	if (orig_resid == uio->uio_resid && orig_resid &&
	    (flags & MSG_EOR) == 0 && (so->so_state & SS_CANTRCVMORE) == 0) {
		sbunlock(&so->so_rcv);
		splx(s);
		goto restart;
	}
		
	if (flagsp)
		*flagsp |= flags;
 release:
	sbunlock(&so->so_rcv);
	splx(s);
	return (error);
}

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

	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);
	if (how == SHUT_WR || how == SHUT_RDWR)
		return (*pr->pr_usrreq)(so, PRU_SHUTDOWN, (struct mbuf *)0,
		    (struct mbuf *)0, (struct mbuf *)0, (struct proc *)0);
	return (0);
}

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

	sb = &so->so_rcv;
	pr = so->so_proto;
	sb->sb_flags |= SB_NOINTR;
	(void) sblock(sb, M_WAITOK);
	s = splnet();
	socantrcvmore(so);
	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));
	splx(s);
	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose)
		(*pr->pr_domain->dom_dispose)(asb.sb_mb);
	sbrelease(&asb, so);
}

int
sosetopt(struct socket *so, int level, int optname, struct mbuf *m0)
{
	int		error;
	struct mbuf	*m;

	error = 0;
	m = m0;
	if (level != SOL_SOCKET) {
		if (so->so_proto && so->so_proto->pr_ctloutput)
			return ((*so->so_proto->pr_ctloutput)
				  (PRCO_SETOPT, so, level, optname, &m0));
		error = ENOPROTOOPT;
	} else {
		switch (optname) {

		case SO_LINGER:
			if (m == NULL || m->m_len != sizeof(struct linger)) {
				error = EINVAL;
				goto bad;
			}
			so->so_linger = mtod(m, struct linger *)->l_linger;
			/* fall thru... */

		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:
			if (m == NULL || m->m_len < sizeof(int)) {
				error = EINVAL;
				goto bad;
			}
			if (*mtod(m, int *))
				so->so_options |= optname;
			else
				so->so_options &= ~optname;
			break;

		case SO_SNDBUF:
		case SO_RCVBUF:
		case SO_SNDLOWAT:
		case SO_RCVLOWAT:
		    {
			int optval;

			if (m == NULL || m->m_len < sizeof(int)) {
				error = EINVAL;
				goto bad;
			}

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

			switch (optname) {

			case SO_SNDBUF:
			case SO_RCVBUF:
				if (sbreserve(optname == SO_SNDBUF ?
				    &so->so_snd : &so->so_rcv,
				    (u_long) optval, so) == 0) {
					error = ENOBUFS;
					goto bad;
				}
				break;

			/*
			 * Make sure the low-water is never greater than
			 * the high-water.
			 */
			case SO_SNDLOWAT:
				so->so_snd.sb_lowat =
				    (optval > so->so_snd.sb_hiwat) ?
				    so->so_snd.sb_hiwat : optval;
				break;
			case SO_RCVLOWAT:
				so->so_rcv.sb_lowat =
				    (optval > so->so_rcv.sb_hiwat) ?
				    so->so_rcv.sb_hiwat : optval;
				break;
			}
			break;
		    }

		case SO_SNDTIMEO:
		case SO_RCVTIMEO:
		    {
			struct timeval *tv;
			short val;

			if (m == NULL || m->m_len < sizeof(*tv)) {
				error = EINVAL;
				goto bad;
			}
			tv = mtod(m, struct timeval *);
			if (tv->tv_sec > (SHRT_MAX - tv->tv_usec / tick) / hz) {
				error = EDOM;
				goto bad;
			}
			val = tv->tv_sec * hz + tv->tv_usec / tick;
			if (val == 0 && tv->tv_usec != 0)
				val = 1;

			switch (optname) {

			case SO_SNDTIMEO:
				so->so_snd.sb_timeo = val;
				break;
			case SO_RCVTIMEO:
				so->so_rcv.sb_timeo = val;
				break;
			}
			break;
		    }

		default:
			error = ENOPROTOOPT;
			break;
		}
		if (error == 0 && so->so_proto && so->so_proto->pr_ctloutput) {
			(void) ((*so->so_proto->pr_ctloutput)
				  (PRCO_SETOPT, so, level, optname, &m0));
			m = NULL;	/* freed by protocol */
		}
	}
 bad:
	if (m)
		(void) m_free(m);
	return (error);
}

int
sogetopt(struct socket *so, int level, int optname, struct mbuf **mp)
{
	struct mbuf	*m;

	if (level != SOL_SOCKET) {
		if (so->so_proto && so->so_proto->pr_ctloutput) {
			return ((*so->so_proto->pr_ctloutput)
				  (PRCO_GETOPT, so, level, optname, mp));
		} else
			return (ENOPROTOOPT);
	} else {
		m = m_get(M_WAIT, MT_SOOPTS);
		m->m_len = sizeof(int);

		switch (optname) {

		case SO_LINGER:
			m->m_len = sizeof(struct linger);
			mtod(m, struct linger *)->l_onoff =
				so->so_options & SO_LINGER;
			mtod(m, struct linger *)->l_linger = so->so_linger;
			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:
			*mtod(m, int *) = so->so_options & optname;
			break;

		case SO_TYPE:
			*mtod(m, int *) = so->so_type;
			break;

		case SO_ERROR:
			*mtod(m, int *) = so->so_error;
			so->so_error = 0;
			break;

		case SO_SNDBUF:
			*mtod(m, int *) = so->so_snd.sb_hiwat;
			break;

		case SO_RCVBUF:
			*mtod(m, int *) = so->so_rcv.sb_hiwat;
			break;

		case SO_SNDLOWAT:
			*mtod(m, int *) = so->so_snd.sb_lowat;
			break;

		case SO_RCVLOWAT:
			*mtod(m, int *) = so->so_rcv.sb_lowat;
			break;

		case SO_SNDTIMEO:
		case SO_RCVTIMEO:
		    {
			int val = (optname == SO_SNDTIMEO ?
			     so->so_snd.sb_timeo : so->so_rcv.sb_timeo);

			m->m_len = sizeof(struct timeval);
			mtod(m, struct timeval *)->tv_sec = val / hz;
			mtod(m, struct timeval *)->tv_usec =
			    (val % hz) * tick;
			break;
		    }

		default:
			(void)m_free(m);
			return (ENOPROTOOPT);
		}
		*mp = m;
		return (0);
	}
}

void
sohasoutofband(struct socket *so)
{
	fownsignal(so->so_pgid, SIGURG, POLL_PRI, POLLPRI|POLLRDBAND, so);
	selwakeup(&so->so_rcv.sb_sel);
}

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

	so = (struct socket *)kn->kn_fp->f_data;
	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;
}

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

	so = (struct socket *)kn->kn_fp->f_data;
	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;
		return (1);
	}
	if (so->so_error)	/* temporary udp error */
		return (1);
	if (kn->kn_sfflags & NOTE_LOWAT)
		return (kn->kn_data >= kn->kn_sdata);
	return (kn->kn_data >= so->so_rcv.sb_lowat);
}

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

	so = (struct socket *)kn->kn_fp->f_data;
	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;
}

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

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

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

	so = (struct socket *)kn->kn_fp->f_data;

	/*
	 * Set kn_data to number of incoming connections, not
	 * counting partial (incomplete) connections.
	 */ 
	kn->kn_data = so->so_qlen;
	return (kn->kn_data > 0);
}

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 = (struct socket *)kn->kn_fp->f_data;
	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:
		return (1);
	}
	SLIST_INSERT_HEAD(&sb->sb_sel.sel_klist, kn, kn_selnext);
	sb->sb_flags |= SB_KNOTE;
	return (0);
}

#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;
	int s;

	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);

	s = splvm();
	simple_lock(&so_pendfree_slock);
	somaxkva = new_somaxkva;
	wakeup(&socurkva);
	simple_unlock(&so_pendfree_slock);
	splx(s);

	return (error);
}

SYSCTL_SETUP(sysctl_kern_somaxkva_setup, "sysctl kern.somaxkva setup")
{

	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_NODE, "kern", NULL,
		       NULL, 0, NULL, 0,
		       CTL_KERN, CTL_EOL);

	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "somaxkva", NULL,
		       sysctl_kern_somaxkva, 0, NULL, 0,
		       CTL_KERN, KERN_SOMAXKVA, CTL_EOL);
}