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

Revision 1.159, Mon Apr 14 15:42:20 2008 UTC (6 years ago) by ad
Branch: MAIN
CVS Tags: yamt-pf42-baseX, yamt-pf42-base
Branch point for: yamt-pf42
Changes since 1.158: +107 -52 lines

soreceive: dom_externalize/dom_dispose can block. If new messages are
appended while the receiver is blocked, the sockbuf will be corrupted.
Dequeue control messages from the sockbuf and sync its state in one
pass. Only then process the control messages. From FreeBSD.

/*	$NetBSD: uipc_socket.c,v 1.159 2008/04/14 15:42:20 ad Exp $	*/

/*-
 * Copyright (c) 2002, 2007, 2008 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) 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 1.159 2008/04/14 15:42:20 ad 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/filedesc.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 <sys/kauth.h>
#include <sys/mutex.h>
#include <sys/condvar.h>

#include <uvm/uvm.h>

POOL_INIT(socket_pool, sizeof(struct socket), 0, 0, 0, "sockpl", NULL,
    IPL_SOFTNET);

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;

#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;

#ifdef SOSEND_NO_LOAN
int sock_loan_thresh = -1;
#else
int sock_loan_thresh = 4096;
#endif

static kmutex_t so_pendfree_lock;
static struct mbuf *so_pendfree;

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

#define	SOCK_LOAN_CHUNK		65536

static size_t sodopendfree(void);
static size_t sodopendfreel(void);

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

	mutex_enter(&so_pendfree_lock);
	while (socurkva + len > somaxkva) {
		size_t freed;

		/*
		 * try to do pendfree.
		 */

		freed = sodopendfreel();

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

		if (freed)
			continue;

		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);
}

static size_t
sodopendfree(void)
{
	size_t rv;

	mutex_enter(&so_pendfree_lock);
	rv = sodopendfreel();
	mutex_exit(&so_pendfree_lock);

	return rv;
}

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

static size_t
sodopendfreel(void)
{
	struct mbuf *m, *next;
	size_t rv = 0;

	KASSERT(mutex_owned(&so_pendfree_lock));

	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);
	}

	return (rv);
}

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_broadcast(&socurkva_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;

	/* XXX KDASSERT */
	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);
	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);

	sodopendfree();
	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;
}

struct mbuf *
m_intopt(struct socket *so, int val)
{
	struct mbuf *m;

	m = getsombuf(so, MT_SOOPTS);
	m->m_len = sizeof(int);
	*mtod(m, int *) = val;
	return m;
}

void
soinit(void)
{

	mutex_init(&so_pendfree_lock, MUTEX_DEFAULT, IPL_VM);
	cv_init(&socurkva_cv, "sokva");

	/* 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 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)
{
	const struct protosw	*prp;
	struct socket	*so;
	uid_t		uid;
	int		error, s;

	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;
	s = splsoftnet();
	so = pool_get(&socket_pool, PR_WAITOK);
	memset(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
	selinit(&so->so_rcv.sb_sel);
	selinit(&so->so_snd.sb_sel);
	uid = kauth_cred_geteuid(l->l_cred);
	so->so_uidinfo = uid_find(uid);
	error = (*prp->pr_usrreq)(so, PRU_ATTACH, NULL,
	    (struct mbuf *)(long)proto, NULL, l);
	if (error != 0) {
		so->so_state |= SS_NOFDREF;
		sofree(so);
		splx(s);
		return error;
	}
	splx(s);
	*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;

	if ((error = fd_allocfile(&fp, &fd)) != 0)
		return (error);
	fp->f_flag = FREAD|FWRITE;
	fp->f_type = DTYPE_SOCKET;
	fp->f_ops = &socketops;
	error = socreate(domain, &so, type, protocol, l);
	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
sobind(struct socket *so, struct mbuf *nam, struct lwp *l)
{
	int	s, error;

	s = splsoftnet();
	error = (*so->so_proto->pr_usrreq)(so, PRU_BIND, NULL, nam, NULL, l);
	splx(s);
	return error;
}

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

	s = splsoftnet();
	if ((so->so_state & (SS_ISCONNECTED | SS_ISCONNECTING | 
	    SS_ISDISCONNECTING)) != 0)
		return (EOPNOTSUPP);
	error = (*so->so_proto->pr_usrreq)(so, PRU_LISTEN, NULL,
	    NULL, NULL, l);
	if (error != 0) {
		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_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);
	sorflush(so);
	seldestroy(&so->so_rcv.sb_sel);
	seldestroy(&so->so_snd.sb_sel);
	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_nbio)
				goto drop;
			while (so->so_state & SS_ISCONNECTED) {
				error = tsleep((void *)&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,
		    NULL, NULL, NULL, NULL);
		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)
{
	int error;

	KASSERT(so->so_head == NULL);
	error = (*so->so_proto->pr_usrreq)(so, PRU_ABORT, NULL,
	    NULL, NULL, NULL);
	if (error) {
		sofree(so);
	}
	return error;
}

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,
		    NULL, nam, NULL, NULL);
	else
		error = ECONNABORTED;

	splx(s);
	return (error);
}

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

	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,
		    NULL, nam, NULL, l);
	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,
	    NULL, (struct mbuf *)so2, NULL, NULL);
	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,
	    NULL, NULL, NULL, NULL);
 bad:
	splx(s);
	sodopendfree();
	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;

	p = l->l_proc;
	sodopendfree();

	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);
	if (l)
		l->l_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_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 == 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_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, void *), (int)len, uio);
 have_data:
				resid = uio->uio_resid;
				m->m_len = len;
				*mp = m;
				top->m_pkthdr.len += len;
				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);

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

			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:
	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)
{

	/*
	 * 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;
	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;

	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_DONTWAIT) == 0)
		sodopendfree();

	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), NULL, l);
		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;
	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)
		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 == 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);
		error = sbwait(&so->so_rcv);
		splx(s);
		if (error != 0)
			return error;
		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
	 * IPL, 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) {
					splx(s);
					error = (*dom->dom_externalize)(cm, l);
					s = splsoftnet();
				}
				*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) {
				    	splx(s);
					(*dom->dom_dispose)(cm);
					s = splsoftnet();
				}
				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;
		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");
			splx(s);
			error = uiomove(mtod(m, char *) + moff, (int)len, uio);
			s = splsoftnet();
			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)
				*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 == 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");
			error = sbwait(&so->so_rcv);
			if (error != 0) {
				sbunlock(&so->so_rcv);
				splx(s);
				return 0;
			}
			if ((m = so->so_rcv.sb_mb) != NULL)
				nextrecord = m->m_nextpkt;
		}
	}

	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);
		splx(s);
		goto restart;
	}

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

int
soshutdown(struct socket *so, int how)
{
	const 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, NULL,
		    NULL, NULL, NULL);
	return 0;
}

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

static int
sosetopt1(struct socket *so, int level, int optname, struct mbuf *m)
{
	int optval, val;
	struct linger	*l;
	struct sockbuf	*sb;
	struct timeval *tv;

	switch (optname) {

	case SO_LINGER:
		if (m == NULL || m->m_len != sizeof(struct linger))
			return EINVAL;
		l = mtod(m, struct linger *);
		if (l->l_linger < 0 || l->l_linger > USHRT_MAX ||
		    l->l_linger > (INT_MAX / hz))
			return EDOM;
		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:
		if (m == NULL || m->m_len < sizeof(int))
			return EINVAL;
		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:
		if (m == NULL || m->m_len < sizeof(int))
			return EINVAL;

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

		switch (optname) {

		case SO_SNDBUF:
		case SO_RCVBUF:
			sb = (optname == SO_SNDBUF) ?
			    &so->so_snd : &so->so_rcv;
			if (sbreserve(sb, (u_long)optval, so) == 0)
				return ENOBUFS;
			sb->sb_flags &= ~SB_AUTOSIZE;
			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:
		if (m == NULL || m->m_len < sizeof(*tv))
			return EINVAL;
		tv = mtod(m, struct timeval *);
		if (tv->tv_sec > (INT_MAX - tv->tv_usec / tick) / hz)
			return EDOM;
		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:
		return ENOPROTOOPT;
	}
	return 0;
}

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

	if (level == SOL_SOCKET)
		error = sosetopt1(so, level, optname, m);
	else
		error = ENOPROTOOPT;

	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, level,
		    optname, &m);
		if (prerr == 0)
			error = 0;
		else if (prerr != ENOPROTOOPT)
			error = prerr;
	} else if (m != NULL)
		(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) ? 1 : 0;
			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) ? 1 : 0;
			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;
		    }

		case SO_OVERFLOWED:
			*mtod(m, int *) = so->so_rcv.sb_overflowed;
			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);
	selnotify(&so->so_rcv.sb_sel, POLLPRI | POLLRDBAND, 0);
}

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

	so = ((file_t *)kn->kn_obj)->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 = ((file_t *)kn->kn_obj)->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 = ((file_t *)kn->kn_obj)->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 = ((file_t *)kn->kn_obj)->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 = ((file_t *)kn->kn_obj)->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 = ((file_t *)kn->kn_obj)->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 (EINVAL);
	}
	SLIST_INSERT_HEAD(&sb->sb_sel.sel_klist, kn, kn_selnext);
	sb->sb_flags |= SB_KNOTE;
	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;
	int s;

	if ((revents = sodopoll(so, events)) != 0)
		return revents;

	KERNEL_LOCK(1, curlwp);
	s = splsoftnet();

	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_SEL;
		}

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

	splx(s);
	KERNEL_UNLOCK_ONE(curlwp);

	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);
}

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",
		       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);
}