xref: /freebsd/sys/netinet/in_pcb.c (revision 48991a368427cadb9cdac39581d1676c29619c52)
1 /*
2  * Copyright (c) 1982, 1986, 1991, 1993, 1995
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. 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  *	@(#)in_pcb.c	8.4 (Berkeley) 5/24/95
34  *	$Id: in_pcb.c,v 1.14 1995/10/29 15:32:25 phk Exp $
35  */
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/ioctl.h>
45 #include <sys/errno.h>
46 #include <sys/time.h>
47 #include <sys/proc.h>
48 #include <sys/queue.h>
49 
50 #include <net/if.h>
51 #include <net/route.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/in_var.h>
58 #include <netinet/ip_var.h>
59 
60 struct	in_addr zeroin_addr;
61 
62 static void	 in_pcbinshash __P((struct inpcb *));
63 static void	 in_rtchange __P((struct inpcb *, int));
64 
65 int
66 in_pcballoc(so, pcbinfo)
67 	struct socket *so;
68 	struct inpcbinfo *pcbinfo;
69 {
70 	register struct inpcb *inp;
71 	int s;
72 
73 	MALLOC(inp, struct inpcb *, sizeof(*inp), M_PCB, M_NOWAIT);
74 	if (inp == NULL)
75 		return (ENOBUFS);
76 	bzero((caddr_t)inp, sizeof(*inp));
77 	inp->inp_pcbinfo = pcbinfo;
78 	inp->inp_socket = so;
79 	s = splnet();
80 	LIST_INSERT_HEAD(pcbinfo->listhead, inp, inp_list);
81 	in_pcbinshash(inp);
82 	splx(s);
83 	so->so_pcb = (caddr_t)inp;
84 	return (0);
85 }
86 
87 int
88 in_pcbbind(inp, nam)
89 	register struct inpcb *inp;
90 	struct mbuf *nam;
91 {
92 	register struct socket *so = inp->inp_socket;
93 	struct inpcbhead *head = inp->inp_pcbinfo->listhead;
94 	unsigned short *lastport = &inp->inp_pcbinfo->lastport;
95 	struct sockaddr_in *sin;
96 	struct proc *p = curproc;		/* XXX */
97 	u_short lport = 0;
98 	int wild = 0, reuseport = (so->so_options & SO_REUSEPORT);
99 	int error;
100 
101 	if (in_ifaddr == 0)
102 		return (EADDRNOTAVAIL);
103 	if (inp->inp_lport || inp->inp_laddr.s_addr != INADDR_ANY)
104 		return (EINVAL);
105 	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 &&
106 	    ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 ||
107 	     (so->so_options & SO_ACCEPTCONN) == 0))
108 		wild = INPLOOKUP_WILDCARD;
109 	if (nam) {
110 		sin = mtod(nam, struct sockaddr_in *);
111 		if (nam->m_len != sizeof (*sin))
112 			return (EINVAL);
113 #ifdef notdef
114 		/*
115 		 * We should check the family, but old programs
116 		 * incorrectly fail to initialize it.
117 		 */
118 		if (sin->sin_family != AF_INET)
119 			return (EAFNOSUPPORT);
120 #endif
121 		lport = sin->sin_port;
122 		if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr))) {
123 			/*
124 			 * Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
125 			 * allow complete duplication of binding if
126 			 * SO_REUSEPORT is set, or if SO_REUSEADDR is set
127 			 * and a multicast address is bound on both
128 			 * new and duplicated sockets.
129 			 */
130 			if (so->so_options & SO_REUSEADDR)
131 				reuseport = SO_REUSEADDR|SO_REUSEPORT;
132 		} else if (sin->sin_addr.s_addr != INADDR_ANY) {
133 			sin->sin_port = 0;		/* yech... */
134 			if (ifa_ifwithaddr((struct sockaddr *)sin) == 0)
135 				return (EADDRNOTAVAIL);
136 		}
137 		if (lport) {
138 			struct inpcb *t;
139 
140 			/* GROSS */
141 			if (ntohs(lport) < IPPORT_RESERVED &&
142 			    (error = suser(p->p_ucred, &p->p_acflag)))
143 				return (EACCES);
144 			t = in_pcblookup(head, zeroin_addr, 0,
145 			    sin->sin_addr, lport, wild);
146 			if (t && (reuseport & t->inp_socket->so_options) == 0)
147 				return (EADDRINUSE);
148 		}
149 		inp->inp_laddr = sin->sin_addr;
150 	}
151 	if (lport == 0)
152 		do {
153 			++*lastport;
154 			if (*lastport < IPPORT_RESERVED ||
155 			    *lastport > IPPORT_USERRESERVED)
156 				*lastport = IPPORT_RESERVED;
157 			lport = htons(*lastport);
158 		} while (in_pcblookup(head,
159 			    zeroin_addr, 0, inp->inp_laddr, lport, wild));
160 	inp->inp_lport = lport;
161 	in_pcbrehash(inp);
162 	return (0);
163 }
164 
165 /*
166  *   Transform old in_pcbconnect() into an inner subroutine for new
167  *   in_pcbconnect(): Do some validity-checking on the remote
168  *   address (in mbuf 'nam') and then determine local host address
169  *   (i.e., which interface) to use to access that remote host.
170  *
171  *   This preserves definition of in_pcbconnect(), while supporting a
172  *   slightly different version for T/TCP.  (This is more than
173  *   a bit of a kludge, but cleaning up the internal interfaces would
174  *   have forced minor changes in every protocol).
175  */
176 
177 int
178 in_pcbladdr(inp, nam, plocal_sin)
179 	register struct inpcb *inp;
180 	struct mbuf *nam;
181 	struct sockaddr_in **plocal_sin;
182 {
183 	struct in_ifaddr *ia;
184 	register struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
185 
186 	if (nam->m_len != sizeof (*sin))
187 		return (EINVAL);
188 	if (sin->sin_family != AF_INET)
189 		return (EAFNOSUPPORT);
190 	if (sin->sin_port == 0)
191 		return (EADDRNOTAVAIL);
192 	if (in_ifaddr) {
193 		/*
194 		 * If the destination address is INADDR_ANY,
195 		 * use the primary local address.
196 		 * If the supplied address is INADDR_BROADCAST,
197 		 * and the primary interface supports broadcast,
198 		 * choose the broadcast address for that interface.
199 		 */
200 #define	satosin(sa)	((struct sockaddr_in *)(sa))
201 #define sintosa(sin)	((struct sockaddr *)(sin))
202 #define ifatoia(ifa)	((struct in_ifaddr *)(ifa))
203 		if (sin->sin_addr.s_addr == INADDR_ANY)
204 		    sin->sin_addr = IA_SIN(in_ifaddr)->sin_addr;
205 		else if (sin->sin_addr.s_addr == (u_long)INADDR_BROADCAST &&
206 		  (in_ifaddr->ia_ifp->if_flags & IFF_BROADCAST))
207 		    sin->sin_addr = satosin(&in_ifaddr->ia_broadaddr)->sin_addr;
208 	}
209 	if (inp->inp_laddr.s_addr == INADDR_ANY) {
210 		register struct route *ro;
211 
212 		ia = (struct in_ifaddr *)0;
213 		/*
214 		 * If route is known or can be allocated now,
215 		 * our src addr is taken from the i/f, else punt.
216 		 */
217 		ro = &inp->inp_route;
218 		if (ro->ro_rt &&
219 		    (satosin(&ro->ro_dst)->sin_addr.s_addr !=
220 			sin->sin_addr.s_addr ||
221 		    inp->inp_socket->so_options & SO_DONTROUTE)) {
222 			RTFREE(ro->ro_rt);
223 			ro->ro_rt = (struct rtentry *)0;
224 		}
225 		if ((inp->inp_socket->so_options & SO_DONTROUTE) == 0 && /*XXX*/
226 		    (ro->ro_rt == (struct rtentry *)0 ||
227 		    ro->ro_rt->rt_ifp == (struct ifnet *)0)) {
228 			/* No route yet, so try to acquire one */
229 			ro->ro_dst.sa_family = AF_INET;
230 			ro->ro_dst.sa_len = sizeof(struct sockaddr_in);
231 			((struct sockaddr_in *) &ro->ro_dst)->sin_addr =
232 				sin->sin_addr;
233 			rtalloc(ro);
234 		}
235 		/*
236 		 * If we found a route, use the address
237 		 * corresponding to the outgoing interface
238 		 * unless it is the loopback (in case a route
239 		 * to our address on another net goes to loopback).
240 		 */
241 		if (ro->ro_rt && !(ro->ro_rt->rt_ifp->if_flags & IFF_LOOPBACK))
242 			ia = ifatoia(ro->ro_rt->rt_ifa);
243 		if (ia == 0) {
244 			u_short fport = sin->sin_port;
245 
246 			sin->sin_port = 0;
247 			ia = ifatoia(ifa_ifwithdstaddr(sintosa(sin)));
248 			if (ia == 0)
249 				ia = ifatoia(ifa_ifwithnet(sintosa(sin)));
250 			sin->sin_port = fport;
251 			if (ia == 0)
252 				ia = in_ifaddr;
253 			if (ia == 0)
254 				return (EADDRNOTAVAIL);
255 		}
256 		/*
257 		 * If the destination address is multicast and an outgoing
258 		 * interface has been set as a multicast option, use the
259 		 * address of that interface as our source address.
260 		 */
261 		if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)) &&
262 		    inp->inp_moptions != NULL) {
263 			struct ip_moptions *imo;
264 			struct ifnet *ifp;
265 
266 			imo = inp->inp_moptions;
267 			if (imo->imo_multicast_ifp != NULL) {
268 				ifp = imo->imo_multicast_ifp;
269 				for (ia = in_ifaddr; ia; ia = ia->ia_next)
270 					if (ia->ia_ifp == ifp)
271 						break;
272 				if (ia == 0)
273 					return (EADDRNOTAVAIL);
274 			}
275 		}
276 	/*
277 	 * Don't do pcblookup call here; return interface in plocal_sin
278 	 * and exit to caller, that will do the lookup.
279 	 */
280 		*plocal_sin = &ia->ia_addr;
281 
282 	}
283 	return(0);
284 }
285 
286 /*
287  * Outer subroutine:
288  * Connect from a socket to a specified address.
289  * Both address and port must be specified in argument sin.
290  * If don't have a local address for this socket yet,
291  * then pick one.
292  */
293 int
294 in_pcbconnect(inp, nam)
295 	register struct inpcb *inp;
296 	struct mbuf *nam;
297 {
298 	struct sockaddr_in *ifaddr;
299 	register struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
300 	int error;
301 
302 	/*
303 	 *   Call inner routine, to assign local interface address.
304 	 */
305 	if (error = in_pcbladdr(inp, nam, &ifaddr))
306 		return(error);
307 
308 	if (in_pcblookuphash(inp->inp_pcbinfo, sin->sin_addr, sin->sin_port,
309 	    inp->inp_laddr.s_addr ? inp->inp_laddr : ifaddr->sin_addr,
310 	    inp->inp_lport) != NULL)
311 		return (EADDRINUSE);
312 	if (inp->inp_laddr.s_addr == INADDR_ANY) {
313 		if (inp->inp_lport == 0)
314 			(void)in_pcbbind(inp, (struct mbuf *)0);
315 		inp->inp_laddr = ifaddr->sin_addr;
316 	}
317 	inp->inp_faddr = sin->sin_addr;
318 	inp->inp_fport = sin->sin_port;
319 	in_pcbrehash(inp);
320 	return (0);
321 }
322 
323 void
324 in_pcbdisconnect(inp)
325 	struct inpcb *inp;
326 {
327 
328 	inp->inp_faddr.s_addr = INADDR_ANY;
329 	inp->inp_fport = 0;
330 	in_pcbrehash(inp);
331 	if (inp->inp_socket->so_state & SS_NOFDREF)
332 		in_pcbdetach(inp);
333 }
334 
335 void
336 in_pcbdetach(inp)
337 	struct inpcb *inp;
338 {
339 	struct socket *so = inp->inp_socket;
340 	int s;
341 
342 	so->so_pcb = 0;
343 	sofree(so);
344 	if (inp->inp_options)
345 		(void)m_free(inp->inp_options);
346 	if (inp->inp_route.ro_rt)
347 		rtfree(inp->inp_route.ro_rt);
348 	ip_freemoptions(inp->inp_moptions);
349 	s = splnet();
350 	LIST_REMOVE(inp, inp_hash);
351 	LIST_REMOVE(inp, inp_list);
352 	splx(s);
353 	FREE(inp, M_PCB);
354 }
355 
356 void
357 in_setsockaddr(inp, nam)
358 	register struct inpcb *inp;
359 	struct mbuf *nam;
360 {
361 	register struct sockaddr_in *sin;
362 
363 	nam->m_len = sizeof (*sin);
364 	sin = mtod(nam, struct sockaddr_in *);
365 	bzero((caddr_t)sin, sizeof (*sin));
366 	sin->sin_family = AF_INET;
367 	sin->sin_len = sizeof(*sin);
368 	sin->sin_port = inp->inp_lport;
369 	sin->sin_addr = inp->inp_laddr;
370 }
371 
372 void
373 in_setpeeraddr(inp, nam)
374 	struct inpcb *inp;
375 	struct mbuf *nam;
376 {
377 	register struct sockaddr_in *sin;
378 
379 	nam->m_len = sizeof (*sin);
380 	sin = mtod(nam, struct sockaddr_in *);
381 	bzero((caddr_t)sin, sizeof (*sin));
382 	sin->sin_family = AF_INET;
383 	sin->sin_len = sizeof(*sin);
384 	sin->sin_port = inp->inp_fport;
385 	sin->sin_addr = inp->inp_faddr;
386 }
387 
388 /*
389  * Pass some notification to all connections of a protocol
390  * associated with address dst.  The local address and/or port numbers
391  * may be specified to limit the search.  The "usual action" will be
392  * taken, depending on the ctlinput cmd.  The caller must filter any
393  * cmds that are uninteresting (e.g., no error in the map).
394  * Call the protocol specific routine (if any) to report
395  * any errors for each matching socket.
396  *
397  * Must be called at splnet.
398  */
399 void
400 in_pcbnotify(head, dst, fport_arg, laddr, lport_arg, cmd, notify)
401 	struct inpcbhead *head;
402 	struct sockaddr *dst;
403 	u_int fport_arg, lport_arg;
404 	struct in_addr laddr;
405 	int cmd;
406 	void (*notify) __P((struct inpcb *, int));
407 {
408 	register struct inpcb *inp, *oinp;
409 	struct in_addr faddr;
410 	u_short fport = fport_arg, lport = lport_arg;
411 	int errno, s;
412 
413 	if ((unsigned)cmd > PRC_NCMDS || dst->sa_family != AF_INET)
414 		return;
415 	faddr = ((struct sockaddr_in *)dst)->sin_addr;
416 	if (faddr.s_addr == INADDR_ANY)
417 		return;
418 
419 	/*
420 	 * Redirects go to all references to the destination,
421 	 * and use in_rtchange to invalidate the route cache.
422 	 * Dead host indications: notify all references to the destination.
423 	 * Otherwise, if we have knowledge of the local port and address,
424 	 * deliver only to that socket.
425 	 */
426 	if (PRC_IS_REDIRECT(cmd) || cmd == PRC_HOSTDEAD) {
427 		fport = 0;
428 		lport = 0;
429 		laddr.s_addr = 0;
430 		if (cmd != PRC_HOSTDEAD)
431 			notify = in_rtchange;
432 	}
433 	errno = inetctlerrmap[cmd];
434 	s = splnet();
435 	for (inp = head->lh_first; inp != NULL;) {
436 		if (inp->inp_faddr.s_addr != faddr.s_addr ||
437 		    inp->inp_socket == 0 ||
438 		    (lport && inp->inp_lport != lport) ||
439 		    (laddr.s_addr && inp->inp_laddr.s_addr != laddr.s_addr) ||
440 		    (fport && inp->inp_fport != fport)) {
441 			inp = inp->inp_list.le_next;
442 			continue;
443 		}
444 		oinp = inp;
445 		inp = inp->inp_list.le_next;
446 		if (notify)
447 			(*notify)(oinp, errno);
448 	}
449 	splx(s);
450 }
451 
452 /*
453  * Check for alternatives when higher level complains
454  * about service problems.  For now, invalidate cached
455  * routing information.  If the route was created dynamically
456  * (by a redirect), time to try a default gateway again.
457  */
458 void
459 in_losing(inp)
460 	struct inpcb *inp;
461 {
462 	register struct rtentry *rt;
463 	struct rt_addrinfo info;
464 
465 	if ((rt = inp->inp_route.ro_rt)) {
466 		inp->inp_route.ro_rt = 0;
467 		bzero((caddr_t)&info, sizeof(info));
468 		info.rti_info[RTAX_DST] =
469 			(struct sockaddr *)&inp->inp_route.ro_dst;
470 		info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
471 		info.rti_info[RTAX_NETMASK] = rt_mask(rt);
472 		rt_missmsg(RTM_LOSING, &info, rt->rt_flags, 0);
473 		if (rt->rt_flags & RTF_DYNAMIC)
474 			(void) rtrequest(RTM_DELETE, rt_key(rt),
475 				rt->rt_gateway, rt_mask(rt), rt->rt_flags,
476 				(struct rtentry **)0);
477 		else
478 		/*
479 		 * A new route can be allocated
480 		 * the next time output is attempted.
481 		 */
482 			rtfree(rt);
483 	}
484 }
485 
486 /*
487  * After a routing change, flush old routing
488  * and allocate a (hopefully) better one.
489  */
490 static void
491 in_rtchange(inp, errno)
492 	register struct inpcb *inp;
493 	int errno;
494 {
495 	if (inp->inp_route.ro_rt) {
496 		rtfree(inp->inp_route.ro_rt);
497 		inp->inp_route.ro_rt = 0;
498 		/*
499 		 * A new route can be allocated the next time
500 		 * output is attempted.
501 		 */
502 	}
503 }
504 
505 struct inpcb *
506 in_pcblookup(head, faddr, fport_arg, laddr, lport_arg, flags)
507 	struct inpcbhead *head;
508 	struct in_addr faddr, laddr;
509 	u_int fport_arg, lport_arg;
510 	int flags;
511 {
512 	register struct inpcb *inp, *match = NULL;
513 	int matchwild = 3, wildcard;
514 	u_short fport = fport_arg, lport = lport_arg;
515 	int s;
516 
517 	s = splnet();
518 
519 	for (inp = head->lh_first; inp != NULL; inp = inp->inp_list.le_next) {
520 		if (inp->inp_lport != lport)
521 			continue;
522 		wildcard = 0;
523 		if (inp->inp_faddr.s_addr != INADDR_ANY) {
524 			if (faddr.s_addr == INADDR_ANY)
525 				wildcard++;
526 			else if (inp->inp_faddr.s_addr != faddr.s_addr ||
527 			    inp->inp_fport != fport)
528 				continue;
529 		} else {
530 			if (faddr.s_addr != INADDR_ANY)
531 				wildcard++;
532 		}
533 		if (inp->inp_laddr.s_addr != INADDR_ANY) {
534 			if (laddr.s_addr == INADDR_ANY)
535 				wildcard++;
536 			else if (inp->inp_laddr.s_addr != laddr.s_addr)
537 				continue;
538 		} else {
539 			if (laddr.s_addr != INADDR_ANY)
540 				wildcard++;
541 		}
542 		if (wildcard && (flags & INPLOOKUP_WILDCARD) == 0)
543 			continue;
544 		if (wildcard < matchwild) {
545 			match = inp;
546 			matchwild = wildcard;
547 			if (matchwild == 0) {
548 				break;
549 			}
550 		}
551 	}
552 	splx(s);
553 	return (match);
554 }
555 
556 /*
557  * Lookup PCB in hash list.
558  */
559 struct inpcb *
560 in_pcblookuphash(pcbinfo, faddr, fport_arg, laddr, lport_arg)
561 	struct inpcbinfo *pcbinfo;
562 	struct in_addr faddr, laddr;
563 	u_int fport_arg, lport_arg;
564 {
565 	struct inpcbhead *head;
566 	register struct inpcb *inp;
567 	u_short fport = fport_arg, lport = lport_arg;
568 	int s;
569 
570 	s = splnet();
571 	/*
572 	 * First look for an exact match.
573 	 */
574 	head = &pcbinfo->hashbase[(faddr.s_addr + lport + fport) % pcbinfo->hashsize];
575 
576 	for (inp = head->lh_first; inp != NULL; inp = inp->inp_hash.le_next) {
577 		if (inp->inp_faddr.s_addr != faddr.s_addr ||
578 		    inp->inp_fport != fport ||
579 		    inp->inp_lport != lport ||
580 		    inp->inp_laddr.s_addr != laddr.s_addr)
581 			continue;
582 		/*
583 		 * Move PCB to head of this hash chain so that it can be
584 		 * found more quickly in the future.
585 		 */
586 		if (inp != head->lh_first) {
587 			LIST_REMOVE(inp, inp_hash);
588 			LIST_INSERT_HEAD(head, inp, inp_hash);
589 		}
590 		break;
591 	}
592 	splx(s);
593 	return (inp);
594 }
595 
596 /*
597  * Insert PCB into hash chain. Must be called at splnet.
598  */
599 static void
600 in_pcbinshash(inp)
601 	struct inpcb *inp;
602 {
603 	struct inpcbhead *head;
604 
605 	head = &inp->inp_pcbinfo->hashbase[(inp->inp_faddr.s_addr +
606 		inp->inp_lport + inp->inp_fport) % inp->inp_pcbinfo->hashsize];
607 
608 	LIST_INSERT_HEAD(head, inp, inp_hash);
609 }
610 
611 void
612 in_pcbrehash(inp)
613 	struct inpcb *inp;
614 {
615 	struct inpcbhead *head;
616 	int s;
617 
618 	s = splnet();
619 	LIST_REMOVE(inp, inp_hash);
620 
621 	head = &inp->inp_pcbinfo->hashbase[(inp->inp_faddr.s_addr +
622 		inp->inp_lport + inp->inp_fport) % inp->inp_pcbinfo->hashsize];
623 
624 	LIST_INSERT_HEAD(head, inp, inp_hash);
625 	splx(s);
626 }
627