1 /**	$MirOS: src/sys/kern/uipc_socket.c,v 1.4 2005/12/20 19:41:21 tg Exp $ */
2 /*	$OpenBSD: uipc_socket.c,v 1.53 2004/04/19 22:39:07 deraadt Exp $	*/
3 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
4 
5 /*
6  * Copyright (c) 1982, 1986, 1988, 1990, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)uipc_socket.c	8.3 (Berkeley) 4/15/94
34  */
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/proc.h>
39 #include <sys/file.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/domain.h>
43 #include <sys/kernel.h>
44 #include <sys/event.h>
45 #include <sys/protosw.h>
46 #include <sys/socket.h>
47 #include <sys/socketvar.h>
48 #include <sys/signalvar.h>
49 #include <sys/resourcevar.h>
50 #include <sys/pool.h>
51 
52 void 	filt_sordetach(struct knote *kn);
53 int 	filt_soread(struct knote *kn, long hint);
54 void 	filt_sowdetach(struct knote *kn);
55 int	filt_sowrite(struct knote *kn, long hint);
56 int	filt_solisten(struct knote *kn, long hint);
57 
58 struct filterops solisten_filtops =
59 	{ 1, NULL, filt_sordetach, filt_solisten };
60 struct filterops soread_filtops =
61 	{ 1, NULL, filt_sordetach, filt_soread };
62 struct filterops sowrite_filtops =
63 	{ 1, NULL, filt_sowdetach, filt_sowrite };
64 
65 
66 #ifndef SOMINCONN
67 #define SOMINCONN 80
68 #endif /* SOMINCONN */
69 
70 int	somaxconn = SOMAXCONN;
71 int	sominconn = SOMINCONN;
72 
73 struct pool socket_pool;
74 
75 void
soinit(void)76 soinit(void)
77 {
78 
79 	pool_init(&socket_pool, sizeof(struct socket), 0, 0, 0, "sockpl", NULL);
80 }
81 
82 /*
83  * Socket operation routines.
84  * These routines are called by the routines in
85  * sys_socket.c or from a system process, and
86  * implement the semantics of socket operations by
87  * switching out to the protocol specific routines.
88  */
89 /*ARGSUSED*/
90 int
socreate(dom,aso,type,proto)91 socreate(dom, aso, type, proto)
92 	int dom;
93 	struct socket **aso;
94 	register int type;
95 	int proto;
96 {
97 	struct proc *p = curproc;		/* XXX */
98 	struct protosw *prp;
99 	struct socket *so;
100 	int error, s;
101 
102 	if (proto)
103 		prp = pffindproto(dom, proto, type);
104 	else
105 		prp = pffindtype(dom, type);
106 	if (prp == NULL || prp->pr_usrreq == 0)
107 		return (EPROTONOSUPPORT);
108 	if (prp->pr_type != type)
109 		return (EPROTOTYPE);
110 	s = splsoftnet();
111 	so = pool_get(&socket_pool, PR_WAITOK);
112 	bzero(so, sizeof(*so));
113 	TAILQ_INIT(&so->so_q0);
114 	TAILQ_INIT(&so->so_q);
115 	so->so_type = type;
116 	if (p->p_ucred->cr_uid == 0)
117 		so->so_state = SS_PRIV;
118 	so->so_ruid = p->p_cred->p_ruid;
119 	so->so_euid = p->p_ucred->cr_uid;
120 	so->so_rgid = p->p_cred->p_rgid;
121 	so->so_egid = p->p_ucred->cr_gid;
122 	so->so_proto = prp;
123 	error = (*prp->pr_usrreq)(so, PRU_ATTACH, NULL,
124 	    (struct mbuf *)(long)proto, NULL);
125 	if (error) {
126 		so->so_state |= SS_NOFDREF;
127 		sofree(so);
128 		splx(s);
129 		return (error);
130 	}
131 	splx(s);
132 	*aso = so;
133 	return (0);
134 }
135 
136 int
sobind(so,nam)137 sobind(so, nam)
138 	struct socket *so;
139 	struct mbuf *nam;
140 {
141 	int s = splsoftnet();
142 	int error;
143 
144 	error = (*so->so_proto->pr_usrreq)(so, PRU_BIND, NULL, nam, NULL);
145 	splx(s);
146 	return (error);
147 }
148 
149 int
solisten(so,backlog)150 solisten(so, backlog)
151 	register struct socket *so;
152 	int backlog;
153 {
154 	int s = splsoftnet(), error;
155 
156 	error = (*so->so_proto->pr_usrreq)(so, PRU_LISTEN, NULL, NULL, NULL);
157 	if (error) {
158 		splx(s);
159 		return (error);
160 	}
161 	if (TAILQ_FIRST(&so->so_q) == NULL)
162 		so->so_options |= SO_ACCEPTCONN;
163 	if (backlog < 0 || backlog > somaxconn)
164 		backlog = somaxconn;
165 	if (backlog < sominconn)
166 		backlog = sominconn;
167 	so->so_qlimit = backlog;
168 	splx(s);
169 	return (0);
170 }
171 
172 /*
173  *  Must be called at splsoftnet()
174  */
175 
176 void
sofree(struct socket * so)177 sofree(struct socket *so)
178 {
179 	splassert(IPL_SOFTNET);
180 
181 	if (so->so_pcb || (so->so_state & SS_NOFDREF) == 0)
182 		return;
183 	if (so->so_head) {
184 		/*
185 		 * We must not decommission a socket that's on the accept(2)
186 		 * queue.  If we do, then accept(2) may hang after select(2)
187 		 * indicated that the listening socket was ready.
188 		 */
189 		if (!soqremque(so, 0))
190 			return;
191 	}
192 	sbrelease(&so->so_snd);
193 	sorflush(so);
194 	pool_put(&socket_pool, so);
195 }
196 
197 /*
198  * Close a socket on last file table reference removal.
199  * Initiate disconnect if connected.
200  * Free socket when disconnect complete.
201  */
202 int
soclose(so)203 soclose(so)
204 	register struct socket *so;
205 {
206 	struct socket *so2;
207 	int s = splsoftnet();		/* conservative */
208 	int error = 0;
209 
210 	if (so->so_options & SO_ACCEPTCONN) {
211 		while ((so2 = TAILQ_FIRST(&so->so_q0)) != NULL) {
212 			(void) soqremque(so2, 0);
213 			(void) soabort(so2);
214 		}
215 		while ((so2 = TAILQ_FIRST(&so->so_q)) != NULL) {
216 			(void) soqremque(so2, 1);
217 			(void) soabort(so2);
218 		}
219 	}
220 	if (so->so_pcb == 0)
221 		goto discard;
222 	if (so->so_state & SS_ISCONNECTED) {
223 		if ((so->so_state & SS_ISDISCONNECTING) == 0) {
224 			error = sodisconnect(so);
225 			if (error)
226 				goto drop;
227 		}
228 		if (so->so_options & SO_LINGER) {
229 			if ((so->so_state & SS_ISDISCONNECTING) &&
230 			    (so->so_state & SS_NBIO))
231 				goto drop;
232 			while (so->so_state & SS_ISCONNECTED) {
233 				error = tsleep(&so->so_timeo,
234 				    PSOCK | PCATCH, netcls,
235 				    so->so_linger * hz);
236 				if (error)
237 					break;
238 			}
239 		}
240 	}
241 drop:
242 	if (so->so_pcb) {
243 		int error2 = (*so->so_proto->pr_usrreq)(so, PRU_DETACH, NULL,
244 							NULL, NULL);
245 		if (error == 0)
246 			error = error2;
247 	}
248 discard:
249 	if (so->so_state & SS_NOFDREF)
250 		panic("soclose: NOFDREF");
251 	so->so_state |= SS_NOFDREF;
252 	sofree(so);
253 	splx(s);
254 	return (error);
255 }
256 
257 /*
258  * Must be called at splsoftnet.
259  */
260 int
soabort(struct socket * so)261 soabort(struct socket *so)
262 {
263 	splassert(IPL_SOFTNET);
264 
265 	return (*so->so_proto->pr_usrreq)(so, PRU_ABORT, NULL, NULL, NULL);
266 }
267 
268 int
soaccept(so,nam)269 soaccept(so, nam)
270 	register struct socket *so;
271 	struct mbuf *nam;
272 {
273 	int s = splsoftnet();
274 	int error = 0;
275 
276 	if ((so->so_state & SS_NOFDREF) == 0)
277 		panic("soaccept: !NOFDREF");
278 	so->so_state &= ~SS_NOFDREF;
279 	if ((so->so_state & SS_ISDISCONNECTED) == 0 ||
280 	    (so->so_proto->pr_flags & PR_ABRTACPTDIS) == 0)
281 		error = (*so->so_proto->pr_usrreq)(so, PRU_ACCEPT, NULL,
282 		    nam, NULL);
283 	else
284 		error = ECONNABORTED;
285 	splx(s);
286 	return (error);
287 }
288 
289 int
soconnect(so,nam)290 soconnect(so, nam)
291 	register struct socket *so;
292 	struct mbuf *nam;
293 {
294 	int s;
295 	int error;
296 
297 	if (so->so_options & SO_ACCEPTCONN)
298 		return (EOPNOTSUPP);
299 	s = splsoftnet();
300 	/*
301 	 * If protocol is connection-based, can only connect once.
302 	 * Otherwise, if connected, try to disconnect first.
303 	 * This allows user to disconnect by connecting to, e.g.,
304 	 * a null address.
305 	 */
306 	if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
307 	    ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
308 	    (error = sodisconnect(so))))
309 		error = EISCONN;
310 	else
311 		error = (*so->so_proto->pr_usrreq)(so, PRU_CONNECT,
312 						   NULL, nam, NULL);
313 	splx(s);
314 	return (error);
315 }
316 
317 int
soconnect2(so1,so2)318 soconnect2(so1, so2)
319 	register struct socket *so1;
320 	struct socket *so2;
321 {
322 	int s = splsoftnet();
323 	int error;
324 
325 	error = (*so1->so_proto->pr_usrreq)(so1, PRU_CONNECT2, NULL,
326 					    (struct mbuf *)so2, NULL);
327 	splx(s);
328 	return (error);
329 }
330 
331 int
sodisconnect(so)332 sodisconnect(so)
333 	register struct socket *so;
334 {
335 	int s = splsoftnet();
336 	int error;
337 
338 	if ((so->so_state & SS_ISCONNECTED) == 0) {
339 		error = ENOTCONN;
340 		goto bad;
341 	}
342 	if (so->so_state & SS_ISDISCONNECTING) {
343 		error = EALREADY;
344 		goto bad;
345 	}
346 	error = (*so->so_proto->pr_usrreq)(so, PRU_DISCONNECT, NULL, NULL,
347 					   NULL);
348 bad:
349 	splx(s);
350 	return (error);
351 }
352 
353 #define	SBLOCKWAIT(f)	(((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
354 /*
355  * Send on a socket.
356  * If send must go all at once and message is larger than
357  * send buffering, then hard error.
358  * Lock against other senders.
359  * If must go all at once and not enough room now, then
360  * inform user that this would block and do nothing.
361  * Otherwise, if nonblocking, send as much as possible.
362  * The data to be sent is described by "uio" if nonzero,
363  * otherwise by the mbuf chain "top" (which must be null
364  * if uio is not).  Data provided in mbuf chain must be small
365  * enough to send all at once.
366  *
367  * Returns nonzero on error, timeout or signal; callers
368  * must check for short counts if EINTR/ERESTART are returned.
369  * Data and control buffers are freed on return.
370  */
371 int
sosend(so,addr,uio,top,control,flags)372 sosend(so, addr, uio, top, control, flags)
373 	register struct socket *so;
374 	struct mbuf *addr;
375 	struct uio *uio;
376 	struct mbuf *top;
377 	struct mbuf *control;
378 	int flags;
379 {
380 	struct proc *p = curproc;		/* XXX */
381 	struct mbuf **mp;
382 	struct mbuf *m;
383 	long space, len, mlen, clen = 0;
384 	quad_t resid;
385 	int error, s, dontroute;
386 	int atomic = sosendallatonce(so) || top;
387 
388 	if (uio)
389 		resid = uio->uio_resid;
390 	else
391 		resid = top->m_pkthdr.len;
392 	/*
393 	 * In theory resid should be unsigned (since uio->uio_resid is).
394 	 * However, space must be signed, as it might be less than 0
395 	 * if we over-committed, and we must use a signed comparison
396 	 * of space and resid.  On the other hand, a negative resid
397 	 * causes us to loop sending 0-length segments to the protocol.
398 	 * MSG_EOR on a SOCK_STREAM socket is also invalid.
399 	 */
400 	if (resid < 0 ||
401 	    (so->so_type == SOCK_STREAM && (flags & MSG_EOR))) {
402 		error = EINVAL;
403 		goto out;
404 	}
405 	dontroute =
406 	    (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
407 	    (so->so_proto->pr_flags & PR_ATOMIC);
408 	p->p_stats->p_ru.ru_msgsnd++;
409 	if (control)
410 		clen = control->m_len;
411 #define	snderr(errno)	{ error = errno; splx(s); goto release; }
412 
413 restart:
414 	if ((error = sblock(&so->so_snd, SBLOCKWAIT(flags))) != 0)
415 		goto out;
416 	do {
417 		s = splsoftnet();
418 		if (so->so_state & SS_CANTSENDMORE)
419 			snderr(EPIPE);
420 		if (so->so_error) {
421 			error = so->so_error;
422 			so->so_error = 0;
423 			splx(s);
424 			goto release;
425 		}
426 		if ((so->so_state & SS_ISCONNECTED) == 0) {
427 			if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
428 				if ((so->so_state & SS_ISCONFIRMING) == 0 &&
429 				    !(resid == 0 && clen != 0))
430 					snderr(ENOTCONN);
431 			} else if (addr == 0)
432 				snderr(EDESTADDRREQ);
433 		}
434 		space = sbspace(&so->so_snd);
435 		if (flags & MSG_OOB)
436 			space += 1024;
437 		if ((atomic && resid > so->so_snd.sb_hiwat) ||
438 		    clen > so->so_snd.sb_hiwat)
439 			snderr(EMSGSIZE);
440 		if (space < resid + clen && uio &&
441 		    (atomic || space < so->so_snd.sb_lowat || space < clen)) {
442 			if (so->so_state & SS_NBIO)
443 				snderr(EWOULDBLOCK);
444 			sbunlock(&so->so_snd);
445 			error = sbwait(&so->so_snd);
446 			splx(s);
447 			if (error)
448 				goto out;
449 			goto restart;
450 		}
451 		splx(s);
452 		mp = &top;
453 		space -= clen;
454 		do {
455 			if (uio == NULL) {
456 				/*
457 				 * Data is prepackaged in "top".
458 				 */
459 				resid = 0;
460 				if (flags & MSG_EOR)
461 					top->m_flags |= M_EOR;
462 			} else do {
463 				if (top == 0) {
464 					MGETHDR(m, M_WAIT, MT_DATA);
465 					mlen = MHLEN;
466 					m->m_pkthdr.len = 0;
467 					m->m_pkthdr.rcvif = (struct ifnet *)0;
468 				} else {
469 					MGET(m, M_WAIT, MT_DATA);
470 					mlen = MLEN;
471 				}
472 				if (resid >= MINCLSIZE && space >= MCLBYTES) {
473 					MCLGET(m, M_WAIT);
474 					if ((m->m_flags & M_EXT) == 0)
475 						goto nopages;
476 					mlen = MCLBYTES;
477 					if (atomic && top == 0) {
478 						len = lmin(MCLBYTES - max_hdr, resid);
479 						m->m_data += max_hdr;
480 					} else
481 						len = lmin(MCLBYTES, resid);
482 					space -= len;
483 				} else {
484 nopages:
485 					len = lmin(lmin(mlen, resid), space);
486 					space -= len;
487 					/*
488 					 * For datagram protocols, leave room
489 					 * for protocol headers in first mbuf.
490 					 */
491 					if (atomic && top == 0 && len < mlen)
492 						MH_ALIGN(m, len);
493 				}
494 				error = uiomove(mtod(m, caddr_t), (int)len,
495 				    uio);
496 				resid = uio->uio_resid;
497 				m->m_len = len;
498 				*mp = m;
499 				top->m_pkthdr.len += len;
500 				if (error)
501 					goto release;
502 				mp = &m->m_next;
503 				if (resid <= 0) {
504 					if (flags & MSG_EOR)
505 						top->m_flags |= M_EOR;
506 					break;
507 				}
508 			} while (space > 0 && atomic);
509 			if (dontroute)
510 				so->so_options |= SO_DONTROUTE;
511 			s = splsoftnet();		/* XXX */
512 			error = (*so->so_proto->pr_usrreq)(so,
513 			    (flags & MSG_OOB) ? PRU_SENDOOB : PRU_SEND,
514 			    top, addr, control);
515 			splx(s);
516 			if (dontroute)
517 				so->so_options &= ~SO_DONTROUTE;
518 			clen = 0;
519 			control = 0;
520 			top = 0;
521 			mp = &top;
522 			if (error)
523 				goto release;
524 		} while (resid && space > 0);
525 	} while (resid);
526 
527 release:
528 	sbunlock(&so->so_snd);
529 out:
530 	if (top)
531 		m_freem(top);
532 	if (control)
533 		m_freem(control);
534 	return (error);
535 }
536 
537 /*
538  * Implement receive operations on a socket.
539  * We depend on the way that records are added to the sockbuf
540  * by sbappend*.  In particular, each record (mbufs linked through m_next)
541  * must begin with an address if the protocol so specifies,
542  * followed by an optional mbuf or mbufs containing ancillary data,
543  * and then zero or more mbufs of data.
544  * In order to avoid blocking network interrupts for the entire time here,
545  * we splx() while doing the actual copy to user space.
546  * Although the sockbuf is locked, new data may still be appended,
547  * and thus we must maintain consistency of the sockbuf during that time.
548  *
549  * The caller may receive the data as a single mbuf chain by supplying
550  * an mbuf **mp0 for use in returning the chain.  The uio is then used
551  * only for the count in uio_resid.
552  */
553 int
soreceive(so,paddr,uio,mp0,controlp,flagsp)554 soreceive(so, paddr, uio, mp0, controlp, flagsp)
555 	register struct socket *so;
556 	struct mbuf **paddr;
557 	struct uio *uio;
558 	struct mbuf **mp0;
559 	struct mbuf **controlp;
560 	int *flagsp;
561 {
562 	register struct mbuf *m, **mp;
563 	register int flags, len, error, s, offset;
564 	struct protosw *pr = so->so_proto;
565 	struct mbuf *nextrecord;
566 	int moff, type = 0;
567 	size_t orig_resid = uio->uio_resid;
568 	int uio_error = 0;
569 	int resid;
570 
571 	mp = mp0;
572 	if (paddr)
573 		*paddr = 0;
574 	if (controlp)
575 		*controlp = 0;
576 	if (flagsp)
577 		flags = *flagsp &~ MSG_EOR;
578 	else
579 		flags = 0;
580 	if (so->so_state & SS_NBIO)
581 		flags |= MSG_DONTWAIT;
582 	if (flags & MSG_OOB) {
583 		m = m_get(M_WAIT, MT_DATA);
584 		error = (*pr->pr_usrreq)(so, PRU_RCVOOB, m,
585 		    (struct mbuf *)(long)(flags & MSG_PEEK), NULL);
586 		if (error)
587 			goto bad;
588 		do {
589 			error = uiomove(mtod(m, caddr_t),
590 			    (int) min(uio->uio_resid, m->m_len), uio);
591 			m = m_free(m);
592 		} while (uio->uio_resid && error == 0 && m);
593 bad:
594 		if (m)
595 			m_freem(m);
596 		return (error);
597 	}
598 	if (mp)
599 		*mp = NULL;
600 	if (so->so_state & SS_ISCONFIRMING && uio->uio_resid)
601 		(*pr->pr_usrreq)(so, PRU_RCVD, NULL, NULL, NULL);
602 
603 restart:
604 	if ((error = sblock(&so->so_rcv, SBLOCKWAIT(flags))) != 0)
605 		return (error);
606 	s = splsoftnet();
607 
608 	m = so->so_rcv.sb_mb;
609 	/*
610 	 * If we have less data than requested, block awaiting more
611 	 * (subject to any timeout) if:
612 	 *   1. the current count is less than the low water mark,
613 	 *   2. MSG_WAITALL is set, and it is possible to do the entire
614 	 *	receive operation at once if we block (resid <= hiwat), or
615 	 *   3. MSG_DONTWAIT is not set.
616 	 * If MSG_WAITALL is set but resid is larger than the receive buffer,
617 	 * we have to do the receive in sections, and thus risk returning
618 	 * a short count if a timeout or signal occurs after we start.
619 	 */
620 	if (m == NULL || (((flags & MSG_DONTWAIT) == 0 &&
621 	    so->so_rcv.sb_cc < uio->uio_resid) &&
622 	    (so->so_rcv.sb_cc < so->so_rcv.sb_lowat ||
623 	    ((flags & MSG_WAITALL) && uio->uio_resid <= so->so_rcv.sb_hiwat)) &&
624 	    m->m_nextpkt == NULL && (pr->pr_flags & PR_ATOMIC) == 0)) {
625 #ifdef DIAGNOSTIC
626 		if (m == NULL && so->so_rcv.sb_cc)
627 			panic("receive 1");
628 #endif
629 		if (so->so_error) {
630 			if (m)
631 				goto dontblock;
632 			error = so->so_error;
633 			if ((flags & MSG_PEEK) == 0)
634 				so->so_error = 0;
635 			goto release;
636 		}
637 		if (so->so_state & SS_CANTRCVMORE) {
638 			if (m)
639 				goto dontblock;
640 			else
641 				goto release;
642 		}
643 		for (; m; m = m->m_next)
644 			if (m->m_type == MT_OOBDATA  || (m->m_flags & M_EOR)) {
645 				m = so->so_rcv.sb_mb;
646 				goto dontblock;
647 			}
648 		if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 &&
649 		    (so->so_proto->pr_flags & PR_CONNREQUIRED)) {
650 			error = ENOTCONN;
651 			goto release;
652 		}
653 		if (uio->uio_resid == 0 && controlp == NULL)
654 			goto release;
655 		if ((so->so_state & SS_NBIO) || (flags & MSG_DONTWAIT)) {
656 			error = EWOULDBLOCK;
657 			goto release;
658 		}
659 		SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 1");
660 		SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 1");
661 		sbunlock(&so->so_rcv);
662 		error = sbwait(&so->so_rcv);
663 		splx(s);
664 		if (error)
665 			return (error);
666 		goto restart;
667 	}
668 dontblock:
669 	/*
670 	 * On entry here, m points to the first record of the socket buffer.
671 	 * While we process the initial mbufs containing address and control
672 	 * info, we save a copy of m->m_nextpkt into nextrecord.
673 	 */
674 #ifdef notyet /* XXXX */
675 	if (uio->uio_procp)
676 		uio->uio_procp->p_stats->p_ru.ru_msgrcv++;
677 #endif
678 	KASSERT(m == so->so_rcv.sb_mb);
679 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 1");
680 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 1");
681 	nextrecord = m->m_nextpkt;
682 	if (pr->pr_flags & PR_ADDR) {
683 #ifdef DIAGNOSTIC
684 		if (m->m_type != MT_SONAME)
685 			panic("receive 1a");
686 #endif
687 		orig_resid = 0;
688 		if (flags & MSG_PEEK) {
689 			if (paddr)
690 				*paddr = m_copy(m, 0, m->m_len);
691 			m = m->m_next;
692 		} else {
693 			sbfree(&so->so_rcv, m);
694 			if (paddr) {
695 				*paddr = m;
696 				so->so_rcv.sb_mb = m->m_next;
697 				m->m_next = 0;
698 				m = so->so_rcv.sb_mb;
699 			} else {
700 				MFREE(m, so->so_rcv.sb_mb);
701 				m = so->so_rcv.sb_mb;
702 			}
703 		}
704 	}
705 	while (m && m->m_type == MT_CONTROL && error == 0) {
706 		if (flags & MSG_PEEK) {
707 			if (controlp)
708 				*controlp = m_copy(m, 0, m->m_len);
709 			m = m->m_next;
710 		} else {
711 			sbfree(&so->so_rcv, m);
712 			if (controlp) {
713 				if (pr->pr_domain->dom_externalize &&
714 				    mtod(m, struct cmsghdr *)->cmsg_type ==
715 				    SCM_RIGHTS)
716 				   error = (*pr->pr_domain->dom_externalize)(m);
717 				*controlp = m;
718 				so->so_rcv.sb_mb = m->m_next;
719 				m->m_next = 0;
720 				m = so->so_rcv.sb_mb;
721 			} else {
722 				MFREE(m, so->so_rcv.sb_mb);
723 				m = so->so_rcv.sb_mb;
724 			}
725 		}
726 		if (controlp) {
727 			orig_resid = 0;
728 			controlp = &(*controlp)->m_next;
729 		}
730 	}
731 
732 	/*
733 	 * If m is non-NULL, we have some data to read.  From now on,
734 	 * make sure to keep sb_lastrecord consistent when working on
735 	 * the last packet on the chain (nextrecord == NULL) and we
736 	 * change m->m_nextpkt.
737 	 */
738 	if (m) {
739 		if ((flags & MSG_PEEK) == 0) {
740 			m->m_nextpkt = nextrecord;
741 			/*
742 			 * If nextrecord == NULL (this is a single chain),
743 			 * then sb_lastrecord may not be valid here if m
744 			 * was changed earlier.
745 			 */
746 			if (nextrecord == NULL) {
747 				KASSERT(so->so_rcv.sb_mb == m);
748 				so->so_rcv.sb_lastrecord = m;
749 			}
750 		}
751 		type = m->m_type;
752 		if (type == MT_OOBDATA)
753 			flags |= MSG_OOB;
754 		if (m->m_flags & M_BCAST)
755 			flags |= MSG_BCAST;
756 		if (m->m_flags & M_MCAST)
757 			flags |= MSG_MCAST;
758 	} else {
759 		if ((flags & MSG_PEEK) == 0) {
760 			KASSERT(so->so_rcv.sb_mb == m);
761 			so->so_rcv.sb_mb = nextrecord;
762 			SB_EMPTY_FIXUP(&so->so_rcv);
763 		}
764 	}
765 	SBLASTRECORDCHK(&so->so_rcv, "soreceive 2");
766 	SBLASTMBUFCHK(&so->so_rcv, "soreceive 2");
767 
768 	moff = 0;
769 	offset = 0;
770 	while (m && uio->uio_resid > 0 && error == 0) {
771 		if (m->m_type == MT_OOBDATA) {
772 			if (type != MT_OOBDATA)
773 				break;
774 		} else if (type == MT_OOBDATA)
775 			break;
776 #ifdef DIAGNOSTIC
777 		else if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
778 			panic("receive 3");
779 #endif
780 		so->so_state &= ~SS_RCVATMARK;
781 		len = uio->uio_resid;
782 		if (so->so_oobmark && len > so->so_oobmark - offset)
783 			len = so->so_oobmark - offset;
784 		if (len > m->m_len - moff)
785 			len = m->m_len - moff;
786 		/*
787 		 * If mp is set, just pass back the mbufs.
788 		 * Otherwise copy them out via the uio, then free.
789 		 * Sockbuf must be consistent here (points to current mbuf,
790 		 * it points to next record) when we drop priority;
791 		 * we must note any additions to the sockbuf when we
792 		 * block interrupts again.
793 		 */
794 		if (mp == NULL && uio_error == 0) {
795 			SBLASTRECORDCHK(&so->so_rcv, "soreceive uiomove");
796 			SBLASTMBUFCHK(&so->so_rcv, "soreceive uiomove");
797 			resid = uio->uio_resid;
798 			splx(s);
799 			uio_error =
800 				uiomove(mtod(m, caddr_t) + moff, (int)len,
801 					uio);
802 			s = splsoftnet();
803 			if (uio_error)
804 				uio->uio_resid = resid - len;
805 		} else
806 			uio->uio_resid -= len;
807 		if (len == m->m_len - moff) {
808 			if (m->m_flags & M_EOR)
809 				flags |= MSG_EOR;
810 			if (flags & MSG_PEEK) {
811 				m = m->m_next;
812 				moff = 0;
813 			} else {
814 				nextrecord = m->m_nextpkt;
815 				sbfree(&so->so_rcv, m);
816 				if (mp) {
817 					*mp = m;
818 					mp = &m->m_next;
819 					so->so_rcv.sb_mb = m = m->m_next;
820 					*mp = NULL;
821 				} else {
822 					MFREE(m, so->so_rcv.sb_mb);
823 					m = so->so_rcv.sb_mb;
824 				}
825 				/*
826 				 * If m != NULL, we also know that
827 				 * so->so_rcv.sb_mb != NULL.
828 				 */
829 				KASSERT(so->so_rcv.sb_mb == m);
830 				if (m) {
831 					m->m_nextpkt = nextrecord;
832 					if (nextrecord == NULL)
833 						so->so_rcv.sb_lastrecord = m;
834 				} else {
835 					so->so_rcv.sb_mb = nextrecord;
836 					SB_EMPTY_FIXUP(&so->so_rcv);
837 				}
838 				SBLASTRECORDCHK(&so->so_rcv, "soreceive 3");
839 				SBLASTMBUFCHK(&so->so_rcv, "soreceive 3");
840 			}
841 		} else {
842 			if (flags & MSG_PEEK)
843 				moff += len;
844 			else {
845 				if (mp)
846 					*mp = m_copym(m, 0, len, M_WAIT);
847 				m->m_data += len;
848 				m->m_len -= len;
849 				so->so_rcv.sb_cc -= len;
850 			}
851 		}
852 		if (so->so_oobmark) {
853 			if ((flags & MSG_PEEK) == 0) {
854 				so->so_oobmark -= len;
855 				if (so->so_oobmark == 0) {
856 					so->so_state |= SS_RCVATMARK;
857 					break;
858 				}
859 			} else {
860 				offset += len;
861 				if (offset == so->so_oobmark)
862 					break;
863 			}
864 		}
865 		if (flags & MSG_EOR)
866 			break;
867 		/*
868 		 * If the MSG_WAITALL flag is set (for non-atomic socket),
869 		 * we must not quit until "uio->uio_resid == 0" or an error
870 		 * termination.  If a signal/timeout occurs, return
871 		 * with a short count but without error.
872 		 * Keep sockbuf locked against other readers.
873 		 */
874 		while (flags & MSG_WAITALL && m == NULL && uio->uio_resid > 0 &&
875 		    !sosendallatonce(so) && !nextrecord) {
876 			if (so->so_error || so->so_state & SS_CANTRCVMORE)
877 				break;
878 			SBLASTRECORDCHK(&so->so_rcv, "soreceive sbwait 2");
879 			SBLASTMBUFCHK(&so->so_rcv, "soreceive sbwait 2");
880 			error = sbwait(&so->so_rcv);
881 			if (error) {
882 				sbunlock(&so->so_rcv);
883 				splx(s);
884 				return (0);
885 			}
886 			if ((m = so->so_rcv.sb_mb) != NULL)
887 				nextrecord = m->m_nextpkt;
888 		}
889 	}
890 
891 	if (m && pr->pr_flags & PR_ATOMIC) {
892 		flags |= MSG_TRUNC;
893 		if ((flags & MSG_PEEK) == 0)
894 			(void) sbdroprecord(&so->so_rcv);
895 	}
896 	if ((flags & MSG_PEEK) == 0) {
897 		if (m == NULL) {
898 			/*
899 			 * First part is an inline SB_EMPTY_FIXUP().  Second
900 			 * part makes sure sb_lastrecord is up-to-date if
901 			 * there is still data in the socket buffer.
902 			 */
903 			so->so_rcv.sb_mb = nextrecord;
904 			if (so->so_rcv.sb_mb == NULL) {
905 				so->so_rcv.sb_mbtail = NULL;
906 				so->so_rcv.sb_lastrecord = NULL;
907 			} else if (nextrecord->m_nextpkt == NULL)
908 				so->so_rcv.sb_lastrecord = nextrecord;
909 		}
910 		SBLASTRECORDCHK(&so->so_rcv, "soreceive 4");
911 		SBLASTMBUFCHK(&so->so_rcv, "soreceive 4");
912 		if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
913 			(*pr->pr_usrreq)(so, PRU_RCVD, NULL,
914 					 (struct mbuf *)(long)flags, NULL);
915 	}
916 	if (orig_resid == uio->uio_resid && orig_resid &&
917 	    (flags & MSG_EOR) == 0 && (so->so_state & SS_CANTRCVMORE) == 0) {
918 		sbunlock(&so->so_rcv);
919 		splx(s);
920 		goto restart;
921 	}
922 
923 	if (uio_error)
924 		error = uio_error;
925 
926 	if (flagsp)
927 		*flagsp |= flags;
928 release:
929 	sbunlock(&so->so_rcv);
930 	splx(s);
931 	return (error);
932 }
933 
934 int
soshutdown(so,how)935 soshutdown(so, how)
936 	register struct socket *so;
937 	register int how;
938 {
939 	register struct protosw *pr = so->so_proto;
940 
941 	how++;
942 	if (how & ~(FREAD|FWRITE))
943 		return (EINVAL);
944 	if (how & FREAD)
945 		sorflush(so);
946 	if (how & FWRITE)
947 		return (*pr->pr_usrreq)(so, PRU_SHUTDOWN, NULL, NULL, NULL);
948 	return (0);
949 }
950 
951 void
sorflush(so)952 sorflush(so)
953 	register struct socket *so;
954 {
955 	register struct sockbuf *sb = &so->so_rcv;
956 	register struct protosw *pr = so->so_proto;
957 	register int s;
958 	struct sockbuf asb;
959 
960 	sb->sb_flags |= SB_NOINTR;
961 	(void) sblock(sb, M_WAITOK);
962 	s = splimp();
963 	socantrcvmore(so);
964 	sbunlock(sb);
965 	asb = *sb;
966 	bzero(sb, sizeof (*sb));
967 	/* XXX - the bzero stumps all over so_rcv */
968 	if (asb.sb_flags & SB_KNOTE) {
969 		sb->sb_sel.si_note = asb.sb_sel.si_note;
970 		sb->sb_flags = SB_KNOTE;
971 	}
972 	splx(s);
973 	if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose)
974 		(*pr->pr_domain->dom_dispose)(asb.sb_mb);
975 	sbrelease(&asb);
976 }
977 
978 int
sosetopt(so,level,optname,m0)979 sosetopt(so, level, optname, m0)
980 	register struct socket *so;
981 	int level, optname;
982 	struct mbuf *m0;
983 {
984 	int error = 0;
985 	register struct mbuf *m = m0;
986 
987 	if (level != SOL_SOCKET) {
988 		if (so->so_proto && so->so_proto->pr_ctloutput)
989 			return ((*so->so_proto->pr_ctloutput)
990 				  (PRCO_SETOPT, so, level, optname, &m0));
991 		error = ENOPROTOOPT;
992 	} else {
993 		switch (optname) {
994 
995 		case SO_LINGER:
996 			if (m == NULL || m->m_len != sizeof (struct linger) ||
997 			    mtod(m, struct linger *)->l_linger < 0 ||
998 			    mtod(m, struct linger *)->l_linger > SHRT_MAX) {
999 				error = EINVAL;
1000 				goto bad;
1001 			}
1002 			so->so_linger = mtod(m, struct linger *)->l_linger;
1003 			/* fall thru... */
1004 
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 			if (m == NULL || m->m_len < sizeof (int)) {
1014 				error = EINVAL;
1015 				goto bad;
1016 			}
1017 			if (*mtod(m, int *))
1018 				so->so_options |= optname;
1019 			else
1020 				so->so_options &= ~optname;
1021 			break;
1022 
1023 		case SO_SNDBUF:
1024 		case SO_RCVBUF:
1025 		case SO_SNDLOWAT:
1026 		case SO_RCVLOWAT:
1027 		    {
1028 			u_long cnt;
1029 			extern u_long unpst_recvspace;
1030 			extern u_long unpst_sendspace;
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, unpst_sendspace) ||
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, unpst_recvspace) ||
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
sogetopt(so,level,optname,mp)1117 sogetopt(so, level, optname, mp)
1118 	register struct socket *so;
1119 	int level, optname;
1120 	struct mbuf **mp;
1121 {
1122 	register struct mbuf *m;
1123 
1124 	if (level != SOL_SOCKET) {
1125 		if (so->so_proto && so->so_proto->pr_ctloutput) {
1126 			return ((*so->so_proto->pr_ctloutput)
1127 				  (PRCO_GETOPT, so, level, optname, mp));
1128 		} else
1129 			return (ENOPROTOOPT);
1130 	} else {
1131 		m = m_get(M_WAIT, MT_SOOPTS);
1132 		m->m_len = sizeof (int);
1133 
1134 		switch (optname) {
1135 
1136 		case SO_LINGER:
1137 			m->m_len = sizeof (struct linger);
1138 			mtod(m, struct linger *)->l_onoff =
1139 				so->so_options & SO_LINGER;
1140 			mtod(m, struct linger *)->l_linger = so->so_linger;
1141 			break;
1142 
1143 		case SO_USELOOPBACK:
1144 		case SO_DONTROUTE:
1145 		case SO_DEBUG:
1146 		case SO_KEEPALIVE:
1147 		case SO_REUSEADDR:
1148 		case SO_REUSEPORT:
1149 		case SO_BROADCAST:
1150 		case SO_OOBINLINE:
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
sohasoutofband(so)1202 sohasoutofband(so)
1203 	register struct socket *so;
1204 {
1205 	csignal(so->so_pgid, SIGURG, so->so_siguid, so->so_sigeuid);
1206 	selwakeup(&so->so_rcv.sb_sel);
1207 }
1208 
1209 int
soo_kqfilter(struct file * fp,struct knote * kn)1210 soo_kqfilter(struct file *fp, struct knote *kn)
1211 {
1212 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1213 	struct sockbuf *sb;
1214 	int s;
1215 
1216 	switch (kn->kn_filter) {
1217 	case EVFILT_READ:
1218 		if (so->so_options & SO_ACCEPTCONN)
1219 			kn->kn_fop = &solisten_filtops;
1220 		else
1221 			kn->kn_fop = &soread_filtops;
1222 		sb = &so->so_rcv;
1223 		break;
1224 	case EVFILT_WRITE:
1225 		kn->kn_fop = &sowrite_filtops;
1226 		sb = &so->so_snd;
1227 		break;
1228 	default:
1229 		return (1);
1230 	}
1231 
1232 	s = splnet();
1233 	SLIST_INSERT_HEAD(&sb->sb_sel.si_note, kn, kn_selnext);
1234 	sb->sb_flags |= SB_KNOTE;
1235 	splx(s);
1236 	return (0);
1237 }
1238 
1239 void
filt_sordetach(struct knote * kn)1240 filt_sordetach(struct knote *kn)
1241 {
1242 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1243 	int s = splnet();
1244 
1245 	SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext);
1246 	if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note))
1247 		so->so_rcv.sb_flags &= ~SB_KNOTE;
1248 	splx(s);
1249 }
1250 
1251 /*ARGSUSED*/
1252 int
filt_soread(struct knote * kn,long hint)1253 filt_soread(struct knote *kn, long hint)
1254 {
1255 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1256 
1257 	kn->kn_data = so->so_rcv.sb_cc;
1258 	if (so->so_state & SS_CANTRCVMORE) {
1259 		kn->kn_flags |= EV_EOF;
1260 		kn->kn_fflags = so->so_error;
1261 		return (1);
1262 	}
1263 	if (so->so_error)	/* temporary udp error */
1264 		return (1);
1265 	if (kn->kn_sfflags & NOTE_LOWAT)
1266 		return (kn->kn_data >= kn->kn_sdata);
1267 	return (kn->kn_data >= so->so_rcv.sb_lowat);
1268 }
1269 
1270 void
filt_sowdetach(struct knote * kn)1271 filt_sowdetach(struct knote *kn)
1272 {
1273 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1274 	int s = splnet();
1275 
1276 	SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext);
1277 	if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note))
1278 		so->so_snd.sb_flags &= ~SB_KNOTE;
1279 	splx(s);
1280 }
1281 
1282 /*ARGSUSED*/
1283 int
filt_sowrite(struct knote * kn,long hint)1284 filt_sowrite(struct knote *kn, long hint)
1285 {
1286 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1287 
1288 	kn->kn_data = sbspace(&so->so_snd);
1289 	if (so->so_state & SS_CANTSENDMORE) {
1290 		kn->kn_flags |= EV_EOF;
1291 		kn->kn_fflags = so->so_error;
1292 		return (1);
1293 	}
1294 	if (so->so_error)	/* temporary udp error */
1295 		return (1);
1296 	if (((so->so_state & SS_ISCONNECTED) == 0) &&
1297 	    (so->so_proto->pr_flags & PR_CONNREQUIRED))
1298 		return (0);
1299 	if (kn->kn_sfflags & NOTE_LOWAT)
1300 		return (kn->kn_data >= kn->kn_sdata);
1301 	return (kn->kn_data >= so->so_snd.sb_lowat);
1302 }
1303 
1304 /*ARGSUSED*/
1305 int
filt_solisten(struct knote * kn,long hint)1306 filt_solisten(struct knote *kn, long hint)
1307 {
1308 	struct socket *so = (struct socket *)kn->kn_fp->f_data;
1309 
1310 	kn->kn_data = so->so_qlen;
1311 	return (so->so_qlen != 0);
1312 }
1313