xref: /netbsd/sys/netinet/in_proto.c (revision 42a2659f)
1 /*	$NetBSD: in_proto.c,v 1.131 2022/09/03 02:53:18 thorpej Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1982, 1986, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)in_proto.c	8.2 (Berkeley) 2/9/95
61  */
62 
63 #include <sys/cdefs.h>
64 __KERNEL_RCSID(0, "$NetBSD: in_proto.c,v 1.131 2022/09/03 02:53:18 thorpej Exp $");
65 
66 #ifdef _KERNEL_OPT
67 #include "opt_mrouting.h"
68 #include "opt_inet.h"
69 #include "opt_ipsec.h"
70 #include "opt_pim.h"
71 #include "opt_gateway.h"
72 #include "opt_dccp.h"
73 #include "opt_sctp.h"
74 #include "opt_compat_netbsd.h"
75 #include "opt_net_mpsafe.h"
76 #endif
77 
78 #include <sys/param.h>
79 #include <sys/socket.h>
80 #include <sys/protosw.h>
81 #include <sys/domain.h>
82 #include <sys/mbuf.h>
83 
84 #include <net/if.h>
85 
86 #include <netinet/in.h>
87 #include <netinet/in_systm.h>
88 #include <netinet/in_var.h>
89 #include <netinet/ip.h>
90 #include <netinet/ip_var.h>
91 #include <netinet/ip_icmp.h>
92 #include <netinet/in_ifattach.h>
93 #include <netinet/in_pcb.h>
94 #include <netinet/in_proto.h>
95 
96 #ifdef INET6
97 #ifndef INET
98 #include <netinet/in.h>
99 #endif
100 #include <netinet/ip6.h>
101 #endif
102 
103 #include <netinet/igmp_var.h>
104 #ifdef PIM
105 #include <netinet/pim_var.h>
106 #endif
107 #include <netinet/tcp.h>
108 #include <netinet/tcp_fsm.h>
109 #include <netinet/tcp_seq.h>
110 #include <netinet/tcp_timer.h>
111 #include <netinet/tcp_var.h>
112 #include <netinet/tcp_debug.h>
113 #include <netinet/udp.h>
114 #include <netinet/udp_var.h>
115 #include <netinet/ip_encap.h>
116 
117 #ifdef DCCP
118 #include <netinet/dccp.h>
119 #include <netinet/dccp_var.h>
120 #endif
121 
122 #ifdef SCTP
123 #include <netinet/sctp.h>
124 #include <netinet/sctp_var.h>
125 #endif
126 
127 /*
128  * TCP/IP protocol family: IP, ICMP, UDP, TCP.
129  */
130 
131 #ifdef IPSEC
132 #include <netipsec/ipsec.h>
133 #include <netipsec/key.h>
134 #endif	/* IPSEC */
135 
136 #include "carp.h"
137 #if NCARP > 0
138 #include <netinet/ip_carp.h>
139 #endif
140 
141 #include "pfsync.h"
142 #if NPFSYNC > 0
143 #include <net/pfvar.h>
144 #include <net/if_pfsync.h>
145 #endif
146 
147 DOMAIN_DEFINE(inetdomain);	/* forward declare and add to link set */
148 
149 /* Wrappers to acquire kernel_lock. */
150 
151 PR_WRAP_CTLINPUT(rip_ctlinput)
PR_WRAP_CTLINPUT(udp_ctlinput)152 PR_WRAP_CTLINPUT(udp_ctlinput)
153 PR_WRAP_CTLINPUT(tcp_ctlinput)
154 
155 #define	rip_ctlinput	rip_ctlinput_wrapper
156 #define	udp_ctlinput	udp_ctlinput_wrapper
157 #define	tcp_ctlinput	tcp_ctlinput_wrapper
158 
159 PR_WRAP_CTLOUTPUT(rip_ctloutput)
160 PR_WRAP_CTLOUTPUT(udp_ctloutput)
161 PR_WRAP_CTLOUTPUT(tcp_ctloutput)
162 
163 #define	rip_ctloutput	rip_ctloutput_wrapper
164 #define	udp_ctloutput	udp_ctloutput_wrapper
165 #define	tcp_ctloutput	tcp_ctloutput_wrapper
166 
167 #ifdef DCCP
168 PR_WRAP_CTLINPUT(dccp_ctlinput)
169 PR_WRAP_CTLOUTPUT(dccp_ctloutput)
170 
171 #define dccp_ctlinput	dccp_ctlinput_wrapper
172 #define dccp_ctloutput	dccp_ctloutput_wrapper
173 #endif
174 
175 #ifdef SCTP
176 PR_WRAP_CTLINPUT(sctp_ctlinput)
177 PR_WRAP_CTLOUTPUT(sctp_ctloutput)
178 
179 #define sctp_ctlinput	sctp_ctlinput_wrapper
180 #define sctp_ctloutput	sctp_ctloutput_wrapper
181 #endif
182 
183 #ifdef NET_MPSAFE
184 PR_WRAP_INPUT(udp_input)
185 PR_WRAP_INPUT(tcp_input)
186 #ifdef DCCP
187 PR_WRAP_INPUT(dccp_input)
188 #endif
189 #ifdef SCTP
190 PR_WRAP_INPUT(sctp_input)
191 #endif
192 PR_WRAP_INPUT(rip_input)
193 #if NPFSYNC > 0
194 PR_WRAP_INPUT(pfsync_input)
195 #endif
196 PR_WRAP_INPUT(igmp_input)
197 #ifdef PIM
198 PR_WRAP_INPUT(pim_input)
199 #endif
200 
201 #define	udp_input		udp_input_wrapper
202 #define	tcp_input		tcp_input_wrapper
203 #define	dccp_input		dccp_input_wrapper
204 #define	sctp_input		sctp_input_wrapper
205 #define	rip_input		rip_input_wrapper
206 #define	pfsync_input		pfsync_input_wrapper
207 #define	igmp_input		igmp_input_wrapper
208 #define	pim_input		pim_input_wrapper
209 #endif
210 
211 #if defined(IPSEC)
212 
213 #ifdef IPSEC_RUMPKERNEL
214 /*
215  * .pr_input = ipsec4_common_input won't be resolved on loading
216  * the ipsec shared library. We need a wrapper anyway.
217  */
218 static void
219 ipsec4_common_input_wrapper(struct mbuf *m, int off, int proto)
220 {
221 
222 	if (ipsec_enabled) {
223 		ipsec4_common_input(m, off, proto);
224 	} else {
225 		m_freem(m);
226 	}
227 }
228 #define	ipsec4_common_input	ipsec4_common_input_wrapper
229 
230 /* The ctlinput functions may not be loaded */
231 #define	IPSEC_WRAP_CTLINPUT(name)			\
232 static void *						\
233 name##_wrapper(int a, const struct sockaddr *b, void *c)\
234 {							\
235 	void *rv;					\
236 	KERNEL_LOCK(1, NULL);				\
237 	if (ipsec_enabled)				\
238 		rv = name(a, b, c);			\
239 	else						\
240 		rv = NULL;				\
241 	KERNEL_UNLOCK_ONE(NULL);			\
242 	return rv;					\
243 }
244 IPSEC_WRAP_CTLINPUT(ah4_ctlinput)
245 IPSEC_WRAP_CTLINPUT(esp4_ctlinput)
246 
247 #else /* !IPSEC_RUMPKERNEL */
248 
249 PR_WRAP_CTLINPUT(ah4_ctlinput)
250 PR_WRAP_CTLINPUT(esp4_ctlinput)
251 
252 #endif /* !IPSEC_RUMPKERNEL */
253 
254 #define	ah4_ctlinput	ah4_ctlinput_wrapper
255 #define	esp4_ctlinput	esp4_ctlinput_wrapper
256 
257 #endif /* IPSEC */
258 
259 const struct protosw inetsw[] = {
260 {	.pr_domain = &inetdomain,
261 	.pr_init = ip_init,
262 	.pr_fasttimo = ip_fasttimo,
263 	.pr_slowtimo = ip_slowtimo,
264 	.pr_drain = ip_drainstub,
265 },
266 {	.pr_type = SOCK_RAW,
267 	.pr_domain = &inetdomain,
268 	.pr_protocol = IPPROTO_ICMP,
269 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
270 	.pr_input = icmp_input,
271 	.pr_ctlinput = rip_ctlinput,
272 	.pr_ctloutput = rip_ctloutput,
273 	.pr_usrreqs = &rip_usrreqs,
274 	.pr_init = icmp_init,
275 },
276 {	.pr_type = SOCK_DGRAM,
277 	.pr_domain = &inetdomain,
278 	.pr_protocol = IPPROTO_UDP,
279 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_PURGEIF,
280 	.pr_input = udp_input,
281 	.pr_ctlinput = udp_ctlinput,
282 	.pr_ctloutput = udp_ctloutput,
283 	.pr_usrreqs = &udp_usrreqs,
284 	.pr_init = udp_init,
285 },
286 {	.pr_type = SOCK_STREAM,
287 	.pr_domain = &inetdomain,
288 	.pr_protocol = IPPROTO_TCP,
289 	.pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_LISTEN|PR_ABRTACPTDIS|PR_PURGEIF,
290 	.pr_input = tcp_input,
291 	.pr_ctlinput = tcp_ctlinput,
292 	.pr_ctloutput = tcp_ctloutput,
293 	.pr_usrreqs = &tcp_usrreqs,
294 	.pr_init = tcp_init,
295 	.pr_fasttimo = tcp_fasttimo,
296 	.pr_drain = tcp_drainstub,
297 },
298 #ifdef DCCP
299 {	.pr_type = SOCK_CONN_DGRAM,
300 	.pr_domain = &inetdomain,
301 	.pr_protocol = IPPROTO_DCCP,
302 	.pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_ATOMIC|PR_LISTEN|PR_ABRTACPTDIS,
303 	.pr_input = dccp_input,
304 	.pr_ctlinput = dccp_ctlinput,
305 	.pr_ctloutput = dccp_ctloutput,
306 	.pr_usrreqs = &dccp_usrreqs,
307 	.pr_init = dccp_init,
308 },
309 #endif
310 #ifdef SCTP
311 {	.pr_type = SOCK_DGRAM,
312 	.pr_domain = &inetdomain,
313 	.pr_protocol = IPPROTO_SCTP,
314 	.pr_flags = PR_ADDR_OPT|PR_WANTRCVD,
315 	.pr_input = sctp_input,
316 	.pr_ctlinput = sctp_ctlinput,
317 	.pr_ctloutput = sctp_ctloutput,
318 	.pr_usrreqs = &sctp_usrreqs,
319 	.pr_init = sctp_init,
320 	.pr_drain = sctp_drain
321 },
322 {	.pr_type = SOCK_SEQPACKET,
323 	.pr_domain = &inetdomain,
324 	.pr_protocol = IPPROTO_SCTP,
325 	.pr_flags = PR_ADDR_OPT|PR_WANTRCVD,
326 	.pr_input = sctp_input,
327 	.pr_ctlinput = sctp_ctlinput,
328 	.pr_ctloutput = sctp_ctloutput,
329 	.pr_usrreqs = &sctp_usrreqs,
330 	.pr_drain = sctp_drain
331 },
332 {	.pr_type = SOCK_STREAM,
333 	.pr_domain = &inetdomain,
334 	.pr_protocol = IPPROTO_SCTP,
335 	.pr_flags = PR_CONNREQUIRED|PR_ADDR_OPT|PR_WANTRCVD|PR_LISTEN,
336 	.pr_input = sctp_input,
337 	.pr_ctlinput = sctp_ctlinput,
338 	.pr_ctloutput = sctp_ctloutput,
339 	.pr_usrreqs = &sctp_usrreqs,
340 	.pr_drain = sctp_drain
341 },
342 #endif /* SCTP */
343 {	.pr_type = SOCK_RAW,
344 	.pr_domain = &inetdomain,
345 	.pr_protocol = IPPROTO_RAW,
346 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_PURGEIF,
347 	.pr_input = rip_input,
348 	.pr_ctlinput = rip_ctlinput,
349 	.pr_ctloutput = rip_ctloutput,
350 	.pr_usrreqs = &rip_usrreqs,
351 },
352 #ifdef GATEWAY
353 {	.pr_domain = &inetdomain,
354 	.pr_protocol = IPPROTO_IP,
355 	.pr_slowtimo = ipflow_slowtimo,
356 	.pr_init = ipflow_poolinit,
357 },
358 #endif /* GATEWAY */
359 #ifdef IPSEC
360 {	.pr_type = SOCK_RAW,
361 	.pr_domain = &inetdomain,
362 	.pr_protocol = IPPROTO_AH,
363 	.pr_flags = PR_ATOMIC|PR_ADDR,
364 	.pr_input = ipsec4_common_input,
365 	.pr_ctlinput = ah4_ctlinput,
366 },
367 {	.pr_type = SOCK_RAW,
368 	.pr_domain = &inetdomain,
369 	.pr_protocol = IPPROTO_ESP,
370 	.pr_flags = PR_ATOMIC|PR_ADDR,
371 	.pr_input = ipsec4_common_input,
372 	.pr_ctlinput = esp4_ctlinput,
373 },
374 {	.pr_type = SOCK_RAW,
375 	.pr_domain = &inetdomain,
376 	.pr_protocol = IPPROTO_IPCOMP,
377 	.pr_flags = PR_ATOMIC|PR_ADDR,
378 	.pr_input = ipsec4_common_input,
379 },
380 #endif /* IPSEC */
381 {	.pr_type = SOCK_RAW,
382 	.pr_domain = &inetdomain,
383 	.pr_protocol = IPPROTO_IPV4,
384 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
385 	.pr_input = encap4_input,
386 	.pr_ctlinput = rip_ctlinput,
387 	.pr_ctloutput = rip_ctloutput,
388 	.pr_usrreqs = &rip_usrreqs,
389 	.pr_init = encap_init,
390 },
391 #ifdef INET6
392 {	.pr_type = SOCK_RAW,
393 	.pr_domain = &inetdomain,
394 	.pr_protocol = IPPROTO_IPV6,
395 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
396 	.pr_input = encap4_input,
397 	.pr_ctlinput = rip_ctlinput,
398 	.pr_ctloutput = rip_ctloutput,
399 	.pr_usrreqs = &rip_usrreqs,
400 	.pr_init = encap_init,
401 },
402 #endif /* INET6 */
403 #if NCARP > 0
404 {	.pr_type = SOCK_RAW,
405 	.pr_domain = &inetdomain,
406 	.pr_protocol = IPPROTO_CARP,
407 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
408 	.pr_input = carp_proto_input,
409 	.pr_ctloutput = rip_ctloutput,
410 	.pr_usrreqs = &rip_usrreqs,
411 	.pr_init = carp_init,
412 },
413 #endif /* NCARP > 0 */
414 {	.pr_type = SOCK_RAW,
415 	.pr_domain = &inetdomain,
416 	.pr_protocol = IPPROTO_L2TP,
417 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
418 	.pr_input = encap4_input,
419 	.pr_ctlinput = rip_ctlinput,
420 	.pr_ctloutput = rip_ctloutput,
421 	.pr_usrreqs = &rip_usrreqs,	/*XXX*/
422 	.pr_init = encap_init,
423 },
424 #if NPFSYNC > 0
425 {	.pr_type = SOCK_RAW,
426 	.pr_domain = &inetdomain,
427 	.pr_protocol = IPPROTO_PFSYNC,
428 	.pr_flags	 = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
429 	.pr_input	 = pfsync_input,
430 	.pr_ctloutput = rip_ctloutput,
431 	.pr_usrreqs	 = &rip_usrreqs,
432 },
433 #endif /* NPFSYNC > 0 */
434 {	.pr_type = SOCK_RAW,
435 	.pr_domain = &inetdomain,
436 	.pr_protocol = IPPROTO_IGMP,
437 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
438 	.pr_input = igmp_input,
439 	.pr_ctloutput = rip_ctloutput,
440 	.pr_ctlinput = rip_ctlinput,
441 	.pr_usrreqs = &rip_usrreqs,
442 	.pr_fasttimo = igmp_fasttimo,
443 	.pr_slowtimo = igmp_slowtimo,
444 	.pr_init = igmp_init,
445 },
446 #ifdef PIM
447 {	.pr_type = SOCK_RAW,
448 	.pr_domain = &inetdomain,
449 	.pr_protocol = IPPROTO_PIM,
450 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
451 	.pr_input = pim_input,
452 	.pr_ctloutput = rip_ctloutput,
453 	.pr_ctlinput = rip_ctlinput,
454 	.pr_usrreqs = &rip_usrreqs,
455 },
456 #endif /* PIM */
457 /* raw wildcard */
458 {	.pr_type = SOCK_RAW,
459 	.pr_domain = &inetdomain,
460 	.pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
461 	.pr_input = rip_input,
462 	.pr_ctloutput = rip_ctloutput,
463 	.pr_ctlinput = rip_ctlinput,
464 	.pr_usrreqs = &rip_usrreqs,
465 	.pr_init = rip_init,
466 },
467 };
468 
469 const struct sockaddr_in in_any = {
470 	  .sin_len = sizeof(struct sockaddr_in)
471 	, .sin_family = AF_INET
472 	, .sin_port = 0
473 	, .sin_addr = {.s_addr = 0 /* INADDR_ANY */}
474 };
475 
476 struct domain inetdomain = {
477 	.dom_family = PF_INET, .dom_name = "internet", .dom_init = NULL,
478 	.dom_externalize = NULL, .dom_dispose = NULL,
479 	.dom_protosw = inetsw,
480 	.dom_protoswNPROTOSW = &inetsw[__arraycount(inetsw)],
481 	.dom_rtattach = rt_inithead,
482 	.dom_rtoffset = 32,
483 	.dom_maxrtkey = sizeof(struct ip_pack4),
484 	.dom_if_up = in_if_up,
485 	.dom_if_down = in_if_down,
486 	.dom_ifattach = in_domifattach,
487 	.dom_ifdetach = in_domifdetach,
488 	.dom_if_link_state_change = in_if_link_state_change,
489 	.dom_link = { NULL },
490 	.dom_mowner = MOWNER_INIT("",""),
491 	.dom_sa_cmpofs = offsetof(struct sockaddr_in, sin_addr),
492 	.dom_sa_cmplen = sizeof(struct in_addr),
493 	.dom_sa_any = (const struct sockaddr *)&in_any,
494 	.dom_sockaddr_const_addr = sockaddr_in_const_addr,
495 	.dom_sockaddr_addr = sockaddr_in_addr,
496 };
497 
498 u_char	ip_protox[IPPROTO_MAX];
499 
500 static void
sockaddr_in_addrlen(const struct sockaddr * sa,socklen_t * slenp)501 sockaddr_in_addrlen(const struct sockaddr *sa, socklen_t *slenp)
502 {
503 	socklen_t slen;
504 
505 	if (slenp == NULL)
506 		return;
507 
508 	slen = sockaddr_getlen(sa);
509 	*slenp = (socklen_t)MIN(sizeof(struct in_addr),
510 	    slen - MIN(slen, offsetof(struct sockaddr_in, sin_addr)));
511 }
512 
513 const void *
sockaddr_in_const_addr(const struct sockaddr * sa,socklen_t * slenp)514 sockaddr_in_const_addr(const struct sockaddr *sa, socklen_t *slenp)
515 {
516 	const struct sockaddr_in *sin;
517 
518 	sockaddr_in_addrlen(sa, slenp);
519 	sin = (const struct sockaddr_in *)sa;
520 	return &sin->sin_addr;
521 }
522 
523 void *
sockaddr_in_addr(struct sockaddr * sa,socklen_t * slenp)524 sockaddr_in_addr(struct sockaddr *sa, socklen_t *slenp)
525 {
526 	struct sockaddr_in *sin;
527 
528 	sockaddr_in_addrlen(sa, slenp);
529 	sin = (struct sockaddr_in *)sa;
530 	return &sin->sin_addr;
531 }
532 
533 int
sockaddr_in_cmp(const struct sockaddr * sa1,const struct sockaddr * sa2)534 sockaddr_in_cmp(const struct sockaddr *sa1, const struct sockaddr *sa2)
535 {
536 	uint_fast8_t len;
537 	const uint_fast8_t addrofs = offsetof(struct sockaddr_in, sin_addr),
538 			   addrend = addrofs + sizeof(struct in_addr);
539 	int rc;
540 	const struct sockaddr_in *sin1, *sin2;
541 
542 	sin1 = satocsin(sa1);
543 	sin2 = satocsin(sa2);
544 
545 	len = MIN(addrend, MIN(sin1->sin_len, sin2->sin_len));
546 
547 	if (len > addrofs &&
548 	     (rc = memcmp(&sin1->sin_addr, &sin2->sin_addr,
549 	                  len - addrofs)) != 0)
550 		return rc;
551 
552 	return sin1->sin_len - sin2->sin_len;
553 }
554