xref: /openbsd-src/sys/kern/uipc_socket.c (revision 850e275390052b330d93020bf619a739a3c277ac)
1 /*	$OpenBSD: uipc_socket.c,v 1.72 2008/08/07 17:43:37 reyk Exp $	*/
2 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1982, 1986, 1988, 1990, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)uipc_socket.c	8.3 (Berkeley) 4/15/94
33  */
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/proc.h>
38 #include <sys/file.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/domain.h>
42 #include <sys/kernel.h>
43 #include <sys/event.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
47 #include <sys/signalvar.h>
48 #include <sys/resourcevar.h>
49 #include <sys/pool.h>
50 
51 void 	filt_sordetach(struct knote *kn);
52 int 	filt_soread(struct knote *kn, long hint);
53 void 	filt_sowdetach(struct knote *kn);
54 int	filt_sowrite(struct knote *kn, long hint);
55 int	filt_solisten(struct knote *kn, long hint);
56 
57 struct filterops solisten_filtops =
58 	{ 1, NULL, filt_sordetach, filt_solisten };
59 struct filterops soread_filtops =
60 	{ 1, NULL, filt_sordetach, filt_soread };
61 struct filterops sowrite_filtops =
62 	{ 1, NULL, filt_sowdetach, filt_sowrite };
63 
64 
65 #ifndef SOMINCONN
66 #define SOMINCONN 80
67 #endif /* SOMINCONN */
68 
69 int	somaxconn = SOMAXCONN;
70 int	sominconn = SOMINCONN;
71 
72 struct pool socket_pool;
73 
74 void
75 soinit(void)
76 {
77 
78 	pool_init(&socket_pool, sizeof(struct socket), 0, 0, 0, "sockpl", NULL);
79 }
80 
81 /*
82  * Socket operation routines.
83  * These routines are called by the routines in
84  * sys_socket.c or from a system process, and
85  * implement the semantics of socket operations by
86  * switching out to the protocol specific routines.
87  */
88 /*ARGSUSED*/
89 int
90 socreate(int dom, struct socket **aso, int type, int proto)
91 {
92 	struct proc *p = curproc;		/* XXX */
93 	struct protosw *prp;
94 	struct socket *so;
95 	int error, s;
96 
97 	if (proto)
98 		prp = pffindproto(dom, proto, type);
99 	else
100 		prp = pffindtype(dom, type);
101 	if (prp == NULL || prp->pr_usrreq == 0)
102 		return (EPROTONOSUPPORT);
103 	if (prp->pr_type != type)
104 		return (EPROTOTYPE);
105 	s = splsoftnet();
106 	so = pool_get(&socket_pool, PR_WAITOK | PR_ZERO);
107 	TAILQ_INIT(&so->so_q0);
108 	TAILQ_INIT(&so->so_q);
109 	so->so_type = type;
110 	if (p->p_ucred->cr_uid == 0)
111 		so->so_state = SS_PRIV;
112 	so->so_ruid = p->p_cred->p_ruid;
113 	so->so_euid = p->p_ucred->cr_uid;
114 	so->so_rgid = p->p_cred->p_rgid;
115 	so->so_egid = p->p_ucred->cr_gid;
116 	so->so_cpid = p->p_pid;
117 	so->so_proto = prp;
118 	error = (*prp->pr_usrreq)(so, PRU_ATTACH, NULL,
119 	    (struct mbuf *)(long)proto, NULL, p);
120 	if (error) {
121 		so->so_state |= SS_NOFDREF;
122 		sofree(so);
123 		splx(s);
124 		return (error);
125 	}
126 #ifdef COMPAT_SUNOS
127 	{
128 		extern struct emul emul_sunos;
129 		if (p->p_emul == &emul_sunos && type == SOCK_DGRAM)
130 			so->so_options |= SO_BROADCAST;
131 	}
132 #endif
133 	splx(s);
134 	*aso = so;
135 	return (0);
136 }
137 
138 int
139 sobind(struct socket *so, struct mbuf *nam, struct proc *p)
140 {
141 	int s = splsoftnet();
142 	int error;
143 
144 	error = (*so->so_proto->pr_usrreq)(so, PRU_BIND, NULL, nam, NULL, p);
145 	splx(s);
146 	return (error);
147 }
148 
149 int
150 solisten(struct socket *so, int backlog)
151 {
152 	int s = splsoftnet(), error;
153 
154 	error = (*so->so_proto->pr_usrreq)(so, PRU_LISTEN, NULL, NULL, NULL,
155 	    curproc);
156 	if (error) {
157 		splx(s);
158 		return (error);
159 	}
160 	if (TAILQ_FIRST(&so->so_q) == NULL)
161 		so->so_options |= SO_ACCEPTCONN;
162 	if (backlog < 0 || backlog > somaxconn)
163 		backlog = somaxconn;
164 	if (backlog < sominconn)
165 		backlog = sominconn;
166 	so->so_qlimit = backlog;
167 	splx(s);
168 	return (0);
169 }
170 
171 /*
172  *  Must be called at splsoftnet()
173  */
174 
175 void
176 sofree(struct socket *so)
177 {
178 	splassert(IPL_SOFTNET);
179 
180 	if (so->so_pcb || (so->so_state & SS_NOFDREF) == 0)
181 		return;
182 	if (so->so_head) {
183 		/*
184 		 * We must not decommission a socket that's on the accept(2)
185 		 * queue.  If we do, then accept(2) may hang after select(2)
186 		 * indicated that the listening socket was ready.
187 		 */
188 		if (!soqremque(so, 0))
189 			return;
190 	}
191 	sbrelease(&so->so_snd);
192 	sorflush(so);
193 	pool_put(&socket_pool, so);
194 }
195 
196 /*
197  * Close a socket on last file table reference removal.
198  * Initiate disconnect if connected.
199  * Free socket when disconnect complete.
200  */
201 int
202 soclose(struct socket *so)
203 {
204 	struct socket *so2;
205 	int s = splsoftnet();		/* conservative */
206 	int error = 0;
207 
208 	if (so->so_options & SO_ACCEPTCONN) {
209 		while ((so2 = TAILQ_FIRST(&so->so_q0)) != NULL) {
210 			(void) soqremque(so2, 0);
211 			(void) soabort(so2);
212 		}
213 		while ((so2 = TAILQ_FIRST(&so->so_q)) != NULL) {
214 			(void) soqremque(so2, 1);
215 			(void) soabort(so2);
216 		}
217 	}
218 	if (so->so_pcb == 0)
219 		goto discard;
220 	if (so->so_state & SS_ISCONNECTED) {
221 		if ((so->so_state & SS_ISDISCONNECTING) == 0) {
222 			error = sodisconnect(so);
223 			if (error)
224 				goto drop;
225 		}
226 		if (so->so_options & SO_LINGER) {
227 			if ((so->so_state & SS_ISDISCONNECTING) &&
228 			    (so->so_state & SS_NBIO))
229 				goto drop;
230 			while (so->so_state & SS_ISCONNECTED) {
231 				error = tsleep(&so->so_timeo,
232 				    PSOCK | PCATCH, netcls,
233 				    so->so_linger * hz);
234 				if (error)
235 					break;
236 			}
237 		}
238 	}
239 drop:
240 	if (so->so_pcb) {
241 		int error2 = (*so->so_proto->pr_usrreq)(so, PRU_DETACH, NULL,
242 		    NULL, NULL, curproc);
243 		if (error == 0)
244 			error = error2;
245 	}
246 discard:
247 	if (so->so_state & SS_NOFDREF)
248 		panic("soclose: NOFDREF");
249 	so->so_state |= SS_NOFDREF;
250 	sofree(so);
251 	splx(s);
252 	return (error);
253 }
254 
255 /*
256  * Must be called at splsoftnet.
257  */
258 int
259 soabort(struct socket *so)
260 {
261 	splassert(IPL_SOFTNET);
262 
263 	return (*so->so_proto->pr_usrreq)(so, PRU_ABORT, NULL, NULL, NULL,
264 	   curproc);
265 }
266 
267 int
268 soaccept(struct socket *so, struct mbuf *nam)
269 {
270 	int s = splsoftnet();
271 	int error = 0;
272 
273 	if ((so->so_state & SS_NOFDREF) == 0)
274 		panic("soaccept: !NOFDREF");
275 	so->so_state &= ~SS_NOFDREF;
276 	if ((so->so_state & SS_ISDISCONNECTED) == 0 ||
277 	    (so->so_proto->pr_flags & PR_ABRTACPTDIS) == 0)
278 		error = (*so->so_proto->pr_usrreq)(so, PRU_ACCEPT, NULL,
279 		    nam, NULL, curproc);
280 	else
281 		error = ECONNABORTED;
282 	splx(s);
283 	return (error);
284 }
285 
286 int
287 soconnect(struct socket *so, struct mbuf *nam)
288 {
289 	int s;
290 	int error;
291 
292 	if (so->so_options & SO_ACCEPTCONN)
293 		return (EOPNOTSUPP);
294 	s = splsoftnet();
295 	/*
296 	 * If protocol is connection-based, can only connect once.
297 	 * Otherwise, if connected, try to disconnect first.
298 	 * This allows user to disconnect by connecting to, e.g.,
299 	 * a null address.
300 	 */
301 	if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
302 	    ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
303 	    (error = sodisconnect(so))))
304 		error = EISCONN;
305 	else
306 		error = (*so->so_proto->pr_usrreq)(so, PRU_CONNECT,
307 		    NULL, nam, NULL, curproc);
308 	splx(s);
309 	return (error);
310 }
311 
312 int
313 soconnect2(struct socket *so1, struct socket *so2)
314 {
315 	int s = splsoftnet();
316 	int error;
317 
318 	error = (*so1->so_proto->pr_usrreq)(so1, PRU_CONNECT2, NULL,
319 	    (struct mbuf *)so2, NULL, curproc);
320 	splx(s);
321 	return (error);
322 }
323 
324 int
325 sodisconnect(struct socket *so)
326 {
327 	int s = splsoftnet();
328 	int error;
329 
330 	if ((so->so_state & SS_ISCONNECTED) == 0) {
331 		error = ENOTCONN;
332 		goto bad;
333 	}
334 	if (so->so_state & SS_ISDISCONNECTING) {
335 		error = EALREADY;
336 		goto bad;
337 	}
338 	error = (*so->so_proto->pr_usrreq)(so, PRU_DISCONNECT, NULL, NULL,
339 	    NULL, curproc);
340 bad:
341 	splx(s);
342 	return (error);
343 }
344 
345 #define	SBLOCKWAIT(f)	(((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
346 /*
347  * Send on a socket.
348  * If send must go all at once and message is larger than
349  * send buffering, then hard error.
350  * Lock against other senders.
351  * If must go all at once and not enough room now, then
352  * inform user that this would block and do nothing.
353  * Otherwise, if nonblocking, send as much as possible.
354  * The data to be sent is described by "uio" if nonzero,
355  * otherwise by the mbuf chain "top" (which must be null
356  * if uio is not).  Data provided in mbuf chain must be small
357  * enough to send all at once.
358  *
359  * Returns nonzero on error, timeout or signal; callers
360  * must check for short counts if EINTR/ERESTART are returned.
361  * Data and control buffers are freed on return.
362  */
363 int
364 sosend(struct socket *so, struct mbuf *addr, struct uio *uio, struct mbuf *top,
365     struct mbuf *control, int flags)
366 {
367 	struct mbuf **mp;
368 	struct mbuf *m;
369 	long space, len, mlen, clen = 0;
370 	quad_t resid;
371 	int error, s, dontroute;
372 	int atomic = sosendallatonce(so) || top;
373 
374 	if (uio)
375 		resid = uio->uio_resid;
376 	else
377 		resid = top->m_pkthdr.len;
378 	/*
379 	 * In theory resid should be unsigned (since uio->uio_resid is).
380 	 * However, space must be signed, as it might be less than 0
381 	 * if we over-committed, and we must use a signed comparison
382 	 * of space and resid.  On the other hand, a negative resid
383 	 * causes us to loop sending 0-length segments to the protocol.
384 	 * MSG_EOR on a SOCK_STREAM socket is also invalid.
385 	 */
386 	if (resid < 0 ||
387 	    (so->so_type == SOCK_STREAM && (flags & MSG_EOR))) {
388 		error = EINVAL;
389 		goto out;
390 	}
391 	dontroute =
392 	    (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
393 	    (so->so_proto->pr_flags & PR_ATOMIC);
394 	if (uio && uio->uio_procp)
395 		uio->uio_procp->p_stats->p_ru.ru_msgsnd++;
396 	if (control)
397 		clen = control->m_len;
398 #define	snderr(errno)	{ error = errno; splx(s); goto release; }
399 
400 restart:
401 	if ((error = sblock(&so->so_snd, SBLOCKWAIT(flags))) != 0)
402 		goto out;
403 	so->so_state |= SS_ISSENDING;
404 	do {
405 		s = splsoftnet();
406 		if (so->so_state & SS_CANTSENDMORE)
407 			snderr(EPIPE);
408 		if (so->so_error) {
409 			error = so->so_error;
410 			so->so_error = 0;
411 			splx(s);
412 			goto release;
413 		}
414 		if ((so->so_state & SS_ISCONNECTED) == 0) {
415 			if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
416 				if ((so->so_state & SS_ISCONFIRMING) == 0 &&
417 				    !(resid == 0 && clen != 0))
418 					snderr(ENOTCONN);
419 			} else if (addr == 0)
420 				snderr(EDESTADDRREQ);
421 		}
422 		space = sbspace(&so->so_snd);
423 		if (flags & MSG_OOB)
424 			space += 1024;
425 		if ((atomic && resid > so->so_snd.sb_hiwat) ||
426 		    clen > so->so_snd.sb_hiwat)
427 			snderr(EMSGSIZE);
428 		if (space < resid + clen &&
429 		    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
430 			if (so->so_state & SS_NBIO)
431 				snderr(EWOULDBLOCK);
432 			sbunlock(&so->so_snd);
433 			error = sbwait(&so->so_snd);
434 			so->so_state &= ~SS_ISSENDING;
435 			splx(s);
436 			if (error)
437 				goto out;
438 			goto restart;
439 		}
440 		splx(s);
441 		mp = &top;
442 		space -= clen;
443 		do {
444 			if (uio == NULL) {
445 				/*
446 				 * Data is prepackaged in "top".
447 				 */
448 				resid = 0;
449 				if (flags & MSG_EOR)
450 					top->m_flags |= M_EOR;
451 			} else do {
452 				if (top == 0) {
453 					MGETHDR(m, M_WAIT, MT_DATA);
454 					mlen = MHLEN;
455 					m->m_pkthdr.len = 0;
456 					m->m_pkthdr.rcvif = (struct ifnet *)0;
457 				} else {
458 					MGET(m, M_WAIT, MT_DATA);
459 					mlen = MLEN;
460 				}
461 				if (resid >= MINCLSIZE && space >= MCLBYTES) {
462 					MCLGET(m, M_NOWAIT);
463 					if ((m->m_flags & M_EXT) == 0)
464 						goto nopages;
465 					mlen = MCLBYTES;
466 					if (atomic && top == 0) {
467 						len = lmin(MCLBYTES - max_hdr, resid);
468 						m->m_data += max_hdr;
469 					} else
470 						len = lmin(MCLBYTES, resid);
471 					space -= len;
472 				} else {
473 nopages:
474 					len = lmin(lmin(mlen, resid), space);
475 					space -= len;
476 					/*
477 					 * For datagram protocols, leave room
478 					 * for protocol headers in first mbuf.
479 					 */
480 					if (atomic && top == 0 && len < mlen)
481 						MH_ALIGN(m, len);
482 				}
483 				error = uiomove(mtod(m, caddr_t), (int)len,
484 				    uio);
485 				resid = uio->uio_resid;
486 				m->m_len = len;
487 				*mp = m;
488 				top->m_pkthdr.len += len;
489 				if (error)
490 					goto release;
491 				mp = &m->m_next;
492 				if (resid <= 0) {
493 					if (flags & MSG_EOR)
494 						top->m_flags |= M_EOR;
495 					break;
496 				}
497 			} while (space > 0 && atomic);
498 			if (dontroute)
499 				so->so_options |= SO_DONTROUTE;
500 			s = splsoftnet();		/* XXX */
501 			if (resid <= 0)
502 				so->so_state &= ~SS_ISSENDING;
503 			error = (*so->so_proto->pr_usrreq)(so,
504 			    (flags & MSG_OOB) ? PRU_SENDOOB : PRU_SEND,
505 			    top, addr, control, curproc);
506 			splx(s);
507 			if (dontroute)
508 				so->so_options &= ~SO_DONTROUTE;
509 			clen = 0;
510 			control = 0;
511 			top = 0;
512 			mp = &top;
513 			if (error)
514 				goto release;
515 		} while (resid && space > 0);
516 	} while (resid);
517 
518 release:
519 	so->so_state &= ~SS_ISSENDING;
520 	sbunlock(&so->so_snd);
521 out:
522 	if (top)
523 		m_freem(top);
524 	if (control)
525 		m_freem(control);
526 	return (error);
527 }
528 
529 /*
530  * Implement receive operations on a socket.
531  * We depend on the way that records are added to the sockbuf
532  * by sbappend*.  In particular, each record (mbufs linked through m_next)
533  * must begin with an address if the protocol so specifies,
534  * followed by an optional mbuf or mbufs containing ancillary data,
535  * and then zero or more mbufs of data.
536  * In order to avoid blocking network interrupts for the entire time here,
537  * we splx() while doing the actual copy to user space.
538  * Although the sockbuf is locked, new data may still be appended,
539  * and thus we must maintain consistency of the sockbuf during that time.
540  *
541  * The caller may receive the data as a single mbuf chain by supplying
542  * an mbuf **mp0 for use in returning the chain.  The uio is then used
543  * only for the count in uio_resid.
544  */
545 int
546 soreceive(struct socket *so, struct mbuf **paddr, struct uio *uio,
547     struct mbuf **mp0, struct mbuf **controlp, int *flagsp)
548 {
549 	struct mbuf *m, **mp;
550 	int flags, len, error, s, offset;
551 	struct protosw *pr = so->so_proto;
552 	struct mbuf *nextrecord;
553 	int moff, type = 0;
554 	size_t orig_resid = uio->uio_resid;
555 	int uio_error = 0;
556 	int resid;
557 
558 	mp = mp0;
559 	if (paddr)
560 		*paddr = 0;
561 	if (controlp)
562 		*controlp = 0;
563 	if (flagsp)
564 		flags = *flagsp &~ MSG_EOR;
565 	else
566 		flags = 0;
567 	if (so->so_state & SS_NBIO)
568 		flags |= MSG_DONTWAIT;
569 	if (flags & MSG_OOB) {
570 		m = m_get(M_WAIT, MT_DATA);
571 		error = (*pr->pr_usrreq)(so, PRU_RCVOOB, m,
572 		    (struct mbuf *)(long)(flags & MSG_PEEK), NULL, curproc);
573 		if (error)
574 			goto bad;
575 		do {
576 			error = uiomove(mtod(m, caddr_t),
577 			    (int) min(uio->uio_resid, m->m_len), uio);
578 			m = m_free(m);
579 		} while (uio->uio_resid && error == 0 && m);
580 bad:
581 		if (m)
582 			m_freem(m);
583 		return (error);
584 	}
585 	if (mp)
586 		*mp = NULL;
587 	if (so->so_state & SS_ISCONFIRMING && uio->uio_resid)
588 		(*pr->pr_usrreq)(so, PRU_RCVD, NULL, NULL, NULL, curproc);
589 
590 restart:
591 	if ((error = sblock(&so->so_rcv, SBLOCKWAIT(flags))) != 0)
592 		return (error);
593 	s = splsoftnet();
594 
595 	m = so->so_rcv.sb_mb;
596 	/*
597 	 * If we have less data than requested, block awaiting more
598 	 * (subject to any timeout) if:
599 	 *   1. the current count is less than the low water mark,
600 	 *   2. MSG_WAITALL is set, and it is possible to do the entire
601 	 *	receive operation at once if we block (resid <= hiwat), or
602 	 *   3. MSG_DONTWAIT is not set.
603 	 * If MSG_WAITALL is set but resid is larger than the receive buffer,
604 	 * we have to do the receive in sections, and thus risk returning
605 	 * a short count if a timeout or signal occurs after we start.
606 	 */
607 	if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
608 	    so->so_rcv.sb_cc < uio->uio_resid) &&
609 	    (so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
610 	    ((flags & MSG_WAITALL) && uio->uio_resid <= so->so_rcv.sb_hiwat)) &&
611 	    m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
612 #ifdef DIAGNOSTIC
613 		if (m == NULL && so->so_rcv.sb_cc)
614 			panic("receive 1");
615 #endif
616 		if (so->so_error) {
617 			if (m)
618 				goto dontblock;
619 			error = so->so_error;
620 			if ((flags & MSG_PEEK) == 0)
621 				so->so_error = 0;
622 			goto release;
623 		}
624 		if (so->so_state & SS_CANTRCVMORE) {
625 			if (m)
626 				goto dontblock;
627 			else
628 				goto release;
629 		}
630 		for (; m; m = m->m_next)
631 			if (m->m_type == MT_OOBDATA  || (m->m_flags & M_EOR)) {
632 				m = so->so_rcv.sb_mb;
633 				goto dontblock;
634 			}
635 		if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
636 		    (so->so_proto->pr_flags & PR_CONNREQUIRED)) {
637 			error = ENOTCONN;
638 			goto release;
639 		}
640 		if (uio->uio_resid == 0 && controlp == NULL)
641 			goto release;
642 		if ((so->so_state & SS_NBIO) || (flags & MSG_DONTWAIT)) {
643 			error = EWOULDBLOCK;
644 			goto release;
645 		}
646 		SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 1");
647 		SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 1");
648 		sbunlock(&so->so_rcv);
649 		error = sbwait(&so->so_rcv);
650 		splx(s);
651 		if (error)
652 			return (error);
653 		goto restart;
654 	}
655 dontblock:
656 	/*
657 	 * On entry here, m points to the first record of the socket buffer.
658 	 * While we process the initial mbufs containing address and control
659 	 * info, we save a copy of m->m_nextpkt into nextrecord.
660 	 */
661 	if (uio->uio_procp)
662 		uio->uio_procp->p_stats->p_ru.ru_msgrcv++;
663 	KASSERT(m == so->so_rcv.sb_mb);
664 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 1");
665 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 1");
666 	nextrecord = m->m_nextpkt;
667 	if (pr->pr_flags & PR_ADDR) {
668 #ifdef DIAGNOSTIC
669 		if (m->m_type != MT_SONAME)
670 			panic("receive 1a");
671 #endif
672 		orig_resid = 0;
673 		if (flags & MSG_PEEK) {
674 			if (paddr)
675 				*paddr = m_copy(m, 0, m->m_len);
676 			m = m->m_next;
677 		} else {
678 			sbfree(&so->so_rcv, m);
679 			if (paddr) {
680 				*paddr = m;
681 				so->so_rcv.sb_mb = m->m_next;
682 				m->m_next = 0;
683 				m = so->so_rcv.sb_mb;
684 			} else {
685 				MFREE(m, so->so_rcv.sb_mb);
686 				m = so->so_rcv.sb_mb;
687 			}
688 		}
689 	}
690 	while (m && m->m_type == MT_CONTROL && error == 0) {
691 		if (flags & MSG_PEEK) {
692 			if (controlp)
693 				*controlp = m_copy(m, 0, m->m_len);
694 			m = m->m_next;
695 		} else {
696 			sbfree(&so->so_rcv, m);
697 			if (controlp) {
698 				if (pr->pr_domain->dom_externalize &&
699 				    mtod(m, struct cmsghdr *)->cmsg_type ==
700 				    SCM_RIGHTS)
701 				   error = (*pr->pr_domain->dom_externalize)(m);
702 				*controlp = m;
703 				so->so_rcv.sb_mb = m->m_next;
704 				m->m_next = 0;
705 				m = so->so_rcv.sb_mb;
706 			} else {
707 				/*
708 				 * Dispose of any SCM_RIGHTS message that went
709 				 * through the read path rather than recv.
710 				 */
711 				if (pr->pr_domain->dom_dispose &&
712 				    mtod(m, struct cmsghdr *)->cmsg_type == SCM_RIGHTS)
713 					pr->pr_domain->dom_dispose(m);
714 				MFREE(m, so->so_rcv.sb_mb);
715 				m = so->so_rcv.sb_mb;
716 			}
717 		}
718 		if (controlp) {
719 			orig_resid = 0;
720 			controlp = &(*controlp)->m_next;
721 		}
722 	}
723 
724 	/*
725 	 * If m is non-NULL, we have some data to read.  From now on,
726 	 * make sure to keep sb_lastrecord consistent when working on
727 	 * the last packet on the chain (nextrecord == NULL) and we
728 	 * change m->m_nextpkt.
729 	 */
730 	if (m) {
731 		if ((flags & MSG_PEEK) == 0) {
732 			m->m_nextpkt = nextrecord;
733 			/*
734 			 * If nextrecord == NULL (this is a single chain),
735 			 * then sb_lastrecord may not be valid here if m
736 			 * was changed earlier.
737 			 */
738 			if (nextrecord == NULL) {
739 				KASSERT(so->so_rcv.sb_mb == m);
740 				so->so_rcv.sb_lastrecord = m;
741 			}
742 		}
743 		type = m->m_type;
744 		if (type == MT_OOBDATA)
745 			flags |= MSG_OOB;
746 		if (m->m_flags & M_BCAST)
747 			flags |= MSG_BCAST;
748 		if (m->m_flags & M_MCAST)
749 			flags |= MSG_MCAST;
750 	} else {
751 		if ((flags & MSG_PEEK) == 0) {
752 			KASSERT(so->so_rcv.sb_mb == m);
753 			so->so_rcv.sb_mb = nextrecord;
754 			SB_EMPTY_FIXUP(&so->so_rcv);
755 		}
756 	}
757 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 2");
758 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 2");
759 
760 	moff = 0;
761 	offset = 0;
762 	while (m && uio->uio_resid > 0 && error == 0) {
763 		if (m->m_type == MT_OOBDATA) {
764 			if (type != MT_OOBDATA)
765 				break;
766 		} else if (type == MT_OOBDATA)
767 			break;
768 #ifdef DIAGNOSTIC
769 		else if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
770 			panic("receive 3");
771 #endif
772 		so->so_state &= ~SS_RCVATMARK;
773 		len = uio->uio_resid;
774 		if (so->so_oobmark && len > so->so_oobmark - offset)
775 			len = so->so_oobmark - offset;
776 		if (len > m->m_len - moff)
777 			len = m->m_len - moff;
778 		/*
779 		 * If mp is set, just pass back the mbufs.
780 		 * Otherwise copy them out via the uio, then free.
781 		 * Sockbuf must be consistent here (points to current mbuf,
782 		 * it points to next record) when we drop priority;
783 		 * we must note any additions to the sockbuf when we
784 		 * block interrupts again.
785 		 */
786 		if (mp == NULL && uio_error == 0) {
787 			SBLASTRECORDCHK(&so->so_rcv, "soreceive uiomove");
788 			SBLASTMBUFCHK(&so->so_rcv, "soreceive uiomove");
789 			resid = uio->uio_resid;
790 			splx(s);
791 			uio_error =
792 				uiomove(mtod(m, caddr_t) + moff, (int)len,
793 					uio);
794 			s = splsoftnet();
795 			if (uio_error)
796 				uio->uio_resid = resid - len;
797 		} else
798 			uio->uio_resid -= len;
799 		if (len == m->m_len - moff) {
800 			if (m->m_flags & M_EOR)
801 				flags |= MSG_EOR;
802 			if (flags & MSG_PEEK) {
803 				m = m->m_next;
804 				moff = 0;
805 			} else {
806 				nextrecord = m->m_nextpkt;
807 				sbfree(&so->so_rcv, m);
808 				if (mp) {
809 					*mp = m;
810 					mp = &m->m_next;
811 					so->so_rcv.sb_mb = m = m->m_next;
812 					*mp = NULL;
813 				} else {
814 					MFREE(m, so->so_rcv.sb_mb);
815 					m = so->so_rcv.sb_mb;
816 				}
817 				/*
818 				 * If m != NULL, we also know that
819 				 * so->so_rcv.sb_mb != NULL.
820 				 */
821 				KASSERT(so->so_rcv.sb_mb == m);
822 				if (m) {
823 					m->m_nextpkt = nextrecord;
824 					if (nextrecord == NULL)
825 						so->so_rcv.sb_lastrecord = m;
826 				} else {
827 					so->so_rcv.sb_mb = nextrecord;
828 					SB_EMPTY_FIXUP(&so->so_rcv);
829 				}
830 				SBLASTRECORDCHK(&so->so_rcv, "soreceive 3");
831 				SBLASTMBUFCHK(&so->so_rcv, "soreceive 3");
832 			}
833 		} else {
834 			if (flags & MSG_PEEK)
835 				moff += len;
836 			else {
837 				if (mp)
838 					*mp = m_copym(m, 0, len, M_WAIT);
839 				m->m_data += len;
840 				m->m_len -= len;
841 				so->so_rcv.sb_cc -= len;
842 				so->so_rcv.sb_datacc -= len;
843 			}
844 		}
845 		if (so->so_oobmark) {
846 			if ((flags & MSG_PEEK) == 0) {
847 				so->so_oobmark -= len;
848 				if (so->so_oobmark == 0) {
849 					so->so_state |= SS_RCVATMARK;
850 					break;
851 				}
852 			} else {
853 				offset += len;
854 				if (offset == so->so_oobmark)
855 					break;
856 			}
857 		}
858 		if (flags & MSG_EOR)
859 			break;
860 		/*
861 		 * If the MSG_WAITALL flag is set (for non-atomic socket),
862 		 * we must not quit until "uio->uio_resid == 0" or an error
863 		 * termination.  If a signal/timeout occurs, return
864 		 * with a short count but without error.
865 		 * Keep sockbuf locked against other readers.
866 		 */
867 		while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
868 		    !sosendallatonce(so) && !nextrecord) {
869 			if (so->so_error || so->so_state & SS_CANTRCVMORE)
870 				break;
871 			SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 2");
872 			SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 2");
873 			error = sbwait(&so->so_rcv);
874 			if (error) {
875 				sbunlock(&so->so_rcv);
876 				splx(s);
877 				return (0);
878 			}
879 			if ((m = so->so_rcv.sb_mb) != NULL)
880 				nextrecord = m->m_nextpkt;
881 		}
882 	}
883 
884 	if (m && pr->pr_flags & PR_ATOMIC) {
885 		flags |= MSG_TRUNC;
886 		if ((flags & MSG_PEEK) == 0)
887 			(void) sbdroprecord(&so->so_rcv);
888 	}
889 	if ((flags & MSG_PEEK) == 0) {
890 		if (m == NULL) {
891 			/*
892 			 * First part is an inline SB_EMPTY_FIXUP().  Second
893 			 * part makes sure sb_lastrecord is up-to-date if
894 			 * there is still data in the socket buffer.
895 			 */
896 			so->so_rcv.sb_mb = nextrecord;
897 			if (so->so_rcv.sb_mb == NULL) {
898 				so->so_rcv.sb_mbtail = NULL;
899 				so->so_rcv.sb_lastrecord = NULL;
900 			} else if (nextrecord->m_nextpkt == NULL)
901 				so->so_rcv.sb_lastrecord = nextrecord;
902 		}
903 		SBLASTRECORDCHK(&so->so_rcv, "soreceive 4");
904 		SBLASTMBUFCHK(&so->so_rcv, "soreceive 4");
905 		if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
906 			(*pr->pr_usrreq)(so, PRU_RCVD, NULL,
907 			    (struct mbuf *)(long)flags, NULL, curproc);
908 	}
909 	if (orig_resid == uio->uio_resid && orig_resid &&
910 	    (flags & MSG_EOR) == 0 && (so->so_state & SS_CANTRCVMORE) == 0) {
911 		sbunlock(&so->so_rcv);
912 		splx(s);
913 		goto restart;
914 	}
915 
916 	if (uio_error)
917 		error = uio_error;
918 
919 	if (flagsp)
920 		*flagsp |= flags;
921 release:
922 	sbunlock(&so->so_rcv);
923 	splx(s);
924 	return (error);
925 }
926 
927 int
928 soshutdown(struct socket *so, int how)
929 {
930 	struct protosw *pr = so->so_proto;
931 
932 	switch (how) {
933 	case SHUT_RD:
934 	case SHUT_RDWR:
935 		sorflush(so);
936 		if (how == SHUT_RD)
937 			return (0);
938 		/* FALLTHROUGH */
939 	case SHUT_WR:
940 		return (*pr->pr_usrreq)(so, PRU_SHUTDOWN, NULL, NULL, NULL,
941 		    curproc);
942 	default:
943 		return (EINVAL);
944 	}
945 }
946 
947 void
948 sorflush(struct socket *so)
949 {
950 	struct sockbuf *sb = &so->so_rcv;
951 	struct protosw *pr = so->so_proto;
952 	int s;
953 	struct sockbuf asb;
954 
955 	sb->sb_flags |= SB_NOINTR;
956 	(void) sblock(sb, M_WAITOK);
957 	s = splnet();
958 	socantrcvmore(so);
959 	sbunlock(sb);
960 	asb = *sb;
961 	bzero(sb, sizeof (*sb));
962 	/* XXX - the bzero stumps all over so_rcv */
963 	if (asb.sb_flags & SB_KNOTE) {
964 		sb->sb_sel.si_note = asb.sb_sel.si_note;
965 		sb->sb_flags = SB_KNOTE;
966 	}
967 	splx(s);
968 	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose)
969 		(*pr->pr_domain->dom_dispose)(asb.sb_mb);
970 	sbrelease(&asb);
971 }
972 
973 int
974 sosetopt(struct socket *so, int level, int optname, struct mbuf *m0)
975 {
976 	int error = 0;
977 	struct mbuf *m = m0;
978 
979 	if (level != SOL_SOCKET) {
980 		if (so->so_proto && so->so_proto->pr_ctloutput)
981 			return ((*so->so_proto->pr_ctloutput)
982 				  (PRCO_SETOPT, so, level, optname, &m0));
983 		error = ENOPROTOOPT;
984 	} else {
985 		switch (optname) {
986 		case SO_BINDANY:
987 			if ((error = suser(curproc, 0)) != 0)	/* XXX */
988 				goto bad;
989 			break;
990 		}
991 
992 		switch (optname) {
993 
994 		case SO_LINGER:
995 			if (m == NULL || m->m_len != sizeof (struct linger) ||
996 			    mtod(m, struct linger *)->l_linger < 0 ||
997 			    mtod(m, struct linger *)->l_linger > SHRT_MAX) {
998 				error = EINVAL;
999 				goto bad;
1000 			}
1001 			so->so_linger = mtod(m, struct linger *)->l_linger;
1002 			/* FALLTHROUGH */
1003 
1004 		case SO_BINDANY:
1005 		case SO_DEBUG:
1006 		case SO_KEEPALIVE:
1007 		case SO_DONTROUTE:
1008 		case SO_USELOOPBACK:
1009 		case SO_BROADCAST:
1010 		case SO_REUSEADDR:
1011 		case SO_REUSEPORT:
1012 		case SO_OOBINLINE:
1013 		case SO_JUMBO:
1014 		case SO_TIMESTAMP:
1015 			if (m == NULL || m->m_len < sizeof (int)) {
1016 				error = EINVAL;
1017 				goto bad;
1018 			}
1019 			if (*mtod(m, int *))
1020 				so->so_options |= optname;
1021 			else
1022 				so->so_options &= ~optname;
1023 			break;
1024 
1025 		case SO_SNDBUF:
1026 		case SO_RCVBUF:
1027 		case SO_SNDLOWAT:
1028 		case SO_RCVLOWAT:
1029 		    {
1030 			u_long cnt;
1031 
1032 			if (m == NULL || m->m_len < sizeof (int)) {
1033 				error = EINVAL;
1034 				goto bad;
1035 			}
1036 			cnt = *mtod(m, int *);
1037 			if ((long)cnt <= 0)
1038 				cnt = 1;
1039 			switch (optname) {
1040 
1041 			case SO_SNDBUF:
1042 				if (sbcheckreserve(cnt, so->so_snd.sb_hiwat) ||
1043 				    sbreserve(&so->so_snd, cnt) == 0) {
1044 					error = ENOBUFS;
1045 					goto bad;
1046 				}
1047 				break;
1048 
1049 			case SO_RCVBUF:
1050 				if (sbcheckreserve(cnt, so->so_rcv.sb_hiwat) ||
1051 				    sbreserve(&so->so_rcv, cnt) == 0) {
1052 					error = ENOBUFS;
1053 					goto bad;
1054 				}
1055 				break;
1056 
1057 			case SO_SNDLOWAT:
1058 				so->so_snd.sb_lowat = (cnt > so->so_snd.sb_hiwat) ?
1059 				    so->so_snd.sb_hiwat : cnt;
1060 				break;
1061 			case SO_RCVLOWAT:
1062 				so->so_rcv.sb_lowat = (cnt > so->so_rcv.sb_hiwat) ?
1063 				    so->so_rcv.sb_hiwat : cnt;
1064 				break;
1065 			}
1066 			break;
1067 		    }
1068 
1069 		case SO_SNDTIMEO:
1070 		case SO_RCVTIMEO:
1071 		    {
1072 			struct timeval *tv;
1073 			short val;
1074 
1075 			if (m == NULL || m->m_len < sizeof (*tv)) {
1076 				error = EINVAL;
1077 				goto bad;
1078 			}
1079 			tv = mtod(m, struct timeval *);
1080 			if (tv->tv_sec > (SHRT_MAX - tv->tv_usec / tick) / hz) {
1081 				error = EDOM;
1082 				goto bad;
1083 			}
1084 			val = tv->tv_sec * hz + tv->tv_usec / tick;
1085 			if (val == 0 && tv->tv_usec != 0)
1086 				val = 1;
1087 
1088 			switch (optname) {
1089 
1090 			case SO_SNDTIMEO:
1091 				so->so_snd.sb_timeo = val;
1092 				break;
1093 			case SO_RCVTIMEO:
1094 				so->so_rcv.sb_timeo = val;
1095 				break;
1096 			}
1097 			break;
1098 		    }
1099 
1100 		default:
1101 			error = ENOPROTOOPT;
1102 			break;
1103 		}
1104 		if (error == 0 && so->so_proto && so->so_proto->pr_ctloutput) {
1105 			(void) ((*so->so_proto->pr_ctloutput)
1106 				  (PRCO_SETOPT, so, level, optname, &m0));
1107 			m = NULL;	/* freed by protocol */
1108 		}
1109 	}
1110 bad:
1111 	if (m)
1112 		(void) m_free(m);
1113 	return (error);
1114 }
1115 
1116 int
1117 sogetopt(struct socket *so, int level, int optname, struct mbuf **mp)
1118 {
1119 	struct mbuf *m;
1120 
1121 	if (level != SOL_SOCKET) {
1122 		if (so->so_proto && so->so_proto->pr_ctloutput) {
1123 			return ((*so->so_proto->pr_ctloutput)
1124 				  (PRCO_GETOPT, so, level, optname, mp));
1125 		} else
1126 			return (ENOPROTOOPT);
1127 	} else {
1128 		m = m_get(M_WAIT, MT_SOOPTS);
1129 		m->m_len = sizeof (int);
1130 
1131 		switch (optname) {
1132 
1133 		case SO_LINGER:
1134 			m->m_len = sizeof (struct linger);
1135 			mtod(m, struct linger *)->l_onoff =
1136 				so->so_options & SO_LINGER;
1137 			mtod(m, struct linger *)->l_linger = so->so_linger;
1138 			break;
1139 
1140 		case SO_BINDANY:
1141 		case SO_USELOOPBACK:
1142 		case SO_DONTROUTE:
1143 		case SO_DEBUG:
1144 		case SO_KEEPALIVE:
1145 		case SO_REUSEADDR:
1146 		case SO_REUSEPORT:
1147 		case SO_BROADCAST:
1148 		case SO_OOBINLINE:
1149 		case SO_JUMBO:
1150 		case SO_TIMESTAMP:
1151 			*mtod(m, int *) = so->so_options & optname;
1152 			break;
1153 
1154 		case SO_TYPE:
1155 			*mtod(m, int *) = so->so_type;
1156 			break;
1157 
1158 		case SO_ERROR:
1159 			*mtod(m, int *) = so->so_error;
1160 			so->so_error = 0;
1161 			break;
1162 
1163 		case SO_SNDBUF:
1164 			*mtod(m, int *) = so->so_snd.sb_hiwat;
1165 			break;
1166 
1167 		case SO_RCVBUF:
1168 			*mtod(m, int *) = so->so_rcv.sb_hiwat;
1169 			break;
1170 
1171 		case SO_SNDLOWAT:
1172 			*mtod(m, int *) = so->so_snd.sb_lowat;
1173 			break;
1174 
1175 		case SO_RCVLOWAT:
1176 			*mtod(m, int *) = so->so_rcv.sb_lowat;
1177 			break;
1178 
1179 		case SO_SNDTIMEO:
1180 		case SO_RCVTIMEO:
1181 		    {
1182 			int val = (optname == SO_SNDTIMEO ?
1183 			    so->so_snd.sb_timeo : so->so_rcv.sb_timeo);
1184 
1185 			m->m_len = sizeof(struct timeval);
1186 			mtod(m, struct timeval *)->tv_sec = val / hz;
1187 			mtod(m, struct timeval *)->tv_usec =
1188 			    (val % hz) * tick;
1189 			break;
1190 		    }
1191 
1192 		default:
1193 			(void)m_free(m);
1194 			return (ENOPROTOOPT);
1195 		}
1196 		*mp = m;
1197 		return (0);
1198 	}
1199 }
1200 
1201 void
1202 sohasoutofband(struct socket *so)
1203 {
1204 	csignal(so->so_pgid, SIGURG, so->so_siguid, so->so_sigeuid);
1205 	selwakeup(&so->so_rcv.sb_sel);
1206 }
1207 
1208 int
1209 soo_kqfilter(struct file *fp, struct knote *kn)
1210 {
1211 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1212 	struct sockbuf *sb;
1213 	int s;
1214 
1215 	switch (kn->kn_filter) {
1216 	case EVFILT_READ:
1217 		if (so->so_options & SO_ACCEPTCONN)
1218 			kn->kn_fop = &solisten_filtops;
1219 		else
1220 			kn->kn_fop = &soread_filtops;
1221 		sb = &so->so_rcv;
1222 		break;
1223 	case EVFILT_WRITE:
1224 		kn->kn_fop = &sowrite_filtops;
1225 		sb = &so->so_snd;
1226 		break;
1227 	default:
1228 		return (1);
1229 	}
1230 
1231 	s = splnet();
1232 	SLIST_INSERT_HEAD(&sb->sb_sel.si_note, kn, kn_selnext);
1233 	sb->sb_flags |= SB_KNOTE;
1234 	splx(s);
1235 	return (0);
1236 }
1237 
1238 void
1239 filt_sordetach(struct knote *kn)
1240 {
1241 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1242 	int s = splnet();
1243 
1244 	SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext);
1245 	if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note))
1246 		so->so_rcv.sb_flags &= ~SB_KNOTE;
1247 	splx(s);
1248 }
1249 
1250 /*ARGSUSED*/
1251 int
1252 filt_soread(struct knote *kn, long hint)
1253 {
1254 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1255 
1256 	kn->kn_data = so->so_rcv.sb_cc;
1257 	if (so->so_state & SS_CANTRCVMORE) {
1258 		kn->kn_flags |= EV_EOF;
1259 		kn->kn_fflags = so->so_error;
1260 		return (1);
1261 	}
1262 	if (so->so_error)	/* temporary udp error */
1263 		return (1);
1264 	if (kn->kn_sfflags & NOTE_LOWAT)
1265 		return (kn->kn_data >= kn->kn_sdata);
1266 	return (kn->kn_data >= so->so_rcv.sb_lowat);
1267 }
1268 
1269 void
1270 filt_sowdetach(struct knote *kn)
1271 {
1272 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1273 	int s = splnet();
1274 
1275 	SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext);
1276 	if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note))
1277 		so->so_snd.sb_flags &= ~SB_KNOTE;
1278 	splx(s);
1279 }
1280 
1281 /*ARGSUSED*/
1282 int
1283 filt_sowrite(struct knote *kn, long hint)
1284 {
1285 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1286 
1287 	kn->kn_data = sbspace(&so->so_snd);
1288 	if (so->so_state & SS_CANTSENDMORE) {
1289 		kn->kn_flags |= EV_EOF;
1290 		kn->kn_fflags = so->so_error;
1291 		return (1);
1292 	}
1293 	if (so->so_error)	/* temporary udp error */
1294 		return (1);
1295 	if (((so->so_state & SS_ISCONNECTED) == 0) &&
1296 	    (so->so_proto->pr_flags & PR_CONNREQUIRED))
1297 		return (0);
1298 	if (kn->kn_sfflags & NOTE_LOWAT)
1299 		return (kn->kn_data >= kn->kn_sdata);
1300 	return (kn->kn_data >= so->so_snd.sb_lowat);
1301 }
1302 
1303 /*ARGSUSED*/
1304 int
1305 filt_solisten(struct knote *kn, long hint)
1306 {
1307 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1308 
1309 	kn->kn_data = so->so_qlen;
1310 	return (so->so_qlen != 0);
1311 }
1312