sys/netinet/in_proto.c

   1 /*      $NetBSD: in_proto.c,v 1.98 2009/09/14 10:36:50 degroote 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 1.98 2009/09/14 10:36:50 degroote Exp $");
  65
  66 #include "opt_mrouting.h"
  67 #include "opt_eon.h"                    /* ISO CLNL over IP */
  68 #include "opt_iso.h"                    /* ISO TP tunneled over IP */
  69 #include "opt_inet.h"
  70 #include "opt_ipsec.h"
  71 #include "opt_pim.h"
  72 #include "opt_gateway.h"
  73
  74 #include <sys/param.h>
  75 #include <sys/socket.h>
  76 #include <sys/protosw.h>
  77 #include <sys/domain.h>
  78 #include <sys/mbuf.h>
  79
  80 #include <net/if.h>
  81 #include <net/radix.h>
  82 #include <net/route.h>
  83
  84 #include <netinet/in.h>
  85 #include <netinet/in_systm.h>
  86 #include <netinet/ip.h>
  87 #include <netinet/ip_var.h>
  88 #include <netinet/ip_icmp.h>
  89 #include <netinet/in_ifattach.h>
  90 #include <netinet/in_pcb.h>
  91 #include <netinet/in_proto.h>
  92
  93 #ifdef INET6
  94 #ifndef INET
  95 #include <netinet/in.h>
  96 #endif
  97 #include <netinet/ip6.h>
  98 #endif
  99
 100 #include <netinet/igmp_var.h>
 101 #ifdef PIM
 102 #include <netinet/pim_var.h>
 103 #endif
 104 #include <netinet/tcp.h>
 105 #include <netinet/tcp_fsm.h>
 106 #include <netinet/tcp_seq.h>
 107 #include <netinet/tcp_timer.h>
 108 #include <netinet/tcp_var.h>
 109 #include <netinet/tcpip.h>
 110 #include <netinet/tcp_debug.h>
 111 #include <netinet/udp.h>
 112 #include <netinet/udp_var.h>
 113 #include <netinet/ip_encap.h>
 114
 115 /*
 116  * TCP/IP protocol family: IP, ICMP, UDP, TCP.
 117  */
 118
 119 #ifdef IPSEC
 120 #include <netinet6/ipsec.h>
 121 #include <netinet6/ah.h>
 122 #ifdef IPSEC_ESP
 123 #include <netinet6/esp.h>
 124 #endif
 125 #include <netinet6/ipcomp.h>
 126 #endif /* IPSEC */
 127
 128 #ifdef FAST_IPSEC
 129 #include <netipsec/ipsec.h>
 130 #include <netipsec/key.h>
 131 #endif  /* FAST_IPSEC */
 132
 133 #ifdef TPIP
 134 #include <netiso/tp_param.h>
 135 #include <netiso/tp_var.h>
 136 #endif /* TPIP */
 137
 138 #ifdef EON
 139 #include <netiso/eonvar.h>
 140 #endif /* EON */
 141
 142 #include "carp.h"
 143 #if NCARP > 0
 144 #include <netinet/ip_carp.h>
 145 #endif
 146
 147 #include "pfsync.h"
 148 #if NPFSYNC > 0
 149 #include <net/pfvar.h>
 150 #include <net/if_pfsync.h>
 151 #endif
 152
 153 #include "etherip.h"
 154 #if NETHERIP > 0
 155 #include <netinet/ip_etherip.h>
 156 #endif
 157
 158 DOMAIN_DEFINE(inetdomain);      /* forward declare and add to link set */
 159
 160 /* Wrappers to acquire kernel_lock. */
 161
 162 PR_WRAP_USRREQ(rip_usrreq)
 163 PR_WRAP_USRREQ(udp_usrreq)
 164 PR_WRAP_USRREQ(tcp_usrreq)
 165
 166 #define rip_usrreq      rip_usrreq_wrapper
 167 #define udp_usrreq      udp_usrreq_wrapper
 168 #define tcp_usrreq      tcp_usrreq_wrapper
 169
 170 PR_WRAP_CTLINPUT(rip_ctlinput)
 171 PR_WRAP_CTLINPUT(udp_ctlinput)
 172 PR_WRAP_CTLINPUT(tcp_ctlinput)
 173
 174 #define rip_ctlinput    rip_ctlinput_wrapper
 175 #define udp_ctlinput    udp_ctlinput_wrapper
 176 #define tcp_ctlinput    tcp_ctlinput_wrapper
 177
 178 PR_WRAP_CTLOUTPUT(rip_ctloutput)
 179 PR_WRAP_CTLOUTPUT(udp_ctloutput)
 180 PR_WRAP_CTLOUTPUT(tcp_ctloutput)
 181
 182 #define rip_ctloutput   rip_ctloutput_wrapper
 183 #define udp_ctloutput   udp_ctloutput_wrapper
 184 #define tcp_ctloutput   tcp_ctloutput_wrapper
 185
 186 #if defined(IPSEC) || defined(FAST_IPSEC)
 187 PR_WRAP_CTLINPUT(ah4_ctlinput)
 188
 189 #define ah4_ctlinput    ah4_ctlinput_wrapper
 190 #endif
 191
 192 #if defined(IPSEC_ESP) || defined(FAST_IPSEC)
 193 PR_WRAP_CTLINPUT(esp4_ctlinput)
 194
 195 #define esp4_ctlinput   esp4_ctlinput_wrapper
 196 #endif
 197
 198 #ifdef TPIP
 199 PR_WRAP_CTLOUTPUT(tp_ctloutput)
 200
 201 #define tp_ctloutput    tp_ctloutput_wrapper
 202
 203 PR_WRAP_CTLINPUT(tpip_ctlinput)
 204
 205 #define tpip_ctlinput   tpip_ctlinput_wrapper
 206 #endif
 207
 208 #ifdef EON
 209 PR_WRAP_CTLINPUT(eonctlinput)
 210
 211 #define eonctlinput     eonctlinput_wrapper
 212 #endif
 213
 214 const struct protosw inetsw[] = {
 215 {       .pr_domain = &inetdomain,
 216         .pr_init = ip_init,
 217         .pr_output = ip_output,
 218         .pr_slowtimo = ip_slowtimo,
 219         .pr_drain = ip_drain,
 220 },
 221 {       .pr_type = SOCK_DGRAM,
 222         .pr_domain = &inetdomain,
 223         .pr_protocol = IPPROTO_UDP,
 224         .pr_flags = PR_ATOMIC|PR_ADDR|PR_PURGEIF,
 225         .pr_input = udp_input,
 226         .pr_ctlinput = udp_ctlinput,
 227         .pr_ctloutput = udp_ctloutput,
 228         .pr_usrreq = udp_usrreq,
 229         .pr_init = udp_init,
 230 },
 231 {       .pr_type = SOCK_STREAM,
 232         .pr_domain = &inetdomain,
 233         .pr_protocol = IPPROTO_TCP,
 234         .pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_LISTEN|PR_ABRTACPTDIS|PR_PURGEIF,
 235         .pr_input = tcp_input,
 236         .pr_ctlinput = tcp_ctlinput,
 237         .pr_ctloutput = tcp_ctloutput,
 238         .pr_usrreq = tcp_usrreq,
 239         .pr_init = tcp_init,
 240         .pr_slowtimo = tcp_slowtimo,
 241         .pr_drain = tcp_drain,
 242 },
 243 {       .pr_type = SOCK_RAW,
 244         .pr_domain = &inetdomain,
 245         .pr_protocol = IPPROTO_RAW,
 246         .pr_flags = PR_ATOMIC|PR_ADDR|PR_PURGEIF,
 247         .pr_input = rip_input,
 248         .pr_output = rip_output,
 249         .pr_ctlinput = rip_ctlinput,
 250         .pr_ctloutput = rip_ctloutput,
 251         .pr_usrreq = rip_usrreq,
 252 },
 253 {       .pr_type = SOCK_RAW,
 254         .pr_domain = &inetdomain,
 255         .pr_protocol = IPPROTO_ICMP,
 256         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 257         .pr_input = icmp_input,
 258         .pr_output = rip_output,
 259         .pr_ctlinput = rip_ctlinput,
 260         .pr_ctloutput = rip_ctloutput,
 261         .pr_usrreq = rip_usrreq,
 262         .pr_init = icmp_init,
 263 },
 264 #ifdef GATEWAY
 265 {       .pr_domain = &inetdomain,
 266         .pr_protocol = IPPROTO_IP,
 267         .pr_slowtimo = ipflow_slowtimo,
 268         .pr_init = ipflow_poolinit,
 269 },
 270 #endif /* GATEWAY */
 271 #ifdef IPSEC
 272 {       .pr_type = SOCK_RAW,
 273         .pr_domain = &inetdomain,
 274         .pr_protocol = IPPROTO_AH,
 275         .pr_flags = PR_ATOMIC|PR_ADDR,
 276         .pr_input = ah4_input,
 277         .pr_ctlinput = ah4_ctlinput,
 278         .pr_init = ah4_init,
 279 },
 280 #ifdef IPSEC_ESP
 281 {       .pr_type = SOCK_RAW,
 282         .pr_domain = &inetdomain,
 283         .pr_protocol = IPPROTO_ESP,
 284         .pr_flags = PR_ATOMIC|PR_ADDR,
 285         .pr_input = esp4_input,
 286         .pr_ctlinput = esp4_ctlinput,
 287         .pr_init = esp4_init,
 288 },
 289 #endif /* IPSEC_ESP */
 290 {       .pr_type = SOCK_RAW,
 291         .pr_domain = &inetdomain,
 292         .pr_protocol = IPPROTO_IPCOMP,
 293         .pr_flags = PR_ATOMIC|PR_ADDR,
 294         .pr_input = ipcomp4_input,
 295         .pr_init = ipcomp4_init,
 296 },
 297 #endif /* IPSEC */
 298 #ifdef FAST_IPSEC
 299 {       .pr_type = SOCK_RAW,
 300         .pr_domain = &inetdomain,
 301         .pr_protocol = IPPROTO_AH,
 302         .pr_flags = PR_ATOMIC|PR_ADDR,
 303         .pr_input = ipsec4_common_input,
 304         .pr_ctlinput = ah4_ctlinput,
 305 },
 306 {       .pr_type = SOCK_RAW,
 307         .pr_domain = &inetdomain,
 308         .pr_protocol = IPPROTO_ESP,
 309         .pr_flags = PR_ATOMIC|PR_ADDR,
 310         .pr_input = ipsec4_common_input,
 311         .pr_ctlinput = esp4_ctlinput,
 312 },
 313 {       .pr_type = SOCK_RAW,
 314         .pr_domain = &inetdomain,
 315         .pr_protocol = IPPROTO_IPCOMP,
 316         .pr_flags = PR_ATOMIC|PR_ADDR,
 317         .pr_input = ipsec4_common_input,
 318 },
 319 #endif /* FAST_IPSEC */
 320 {       .pr_type = SOCK_RAW,
 321         .pr_domain = &inetdomain,
 322         .pr_protocol = IPPROTO_IPV4,
 323         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 324         .pr_input = encap4_input,
 325         .pr_output = rip_output,
 326         .pr_ctlinput = rip_ctlinput,
 327         .pr_ctloutput = rip_ctloutput,
 328         .pr_usrreq = rip_usrreq,
 329         .pr_init = encap_init,
 330 },
 331 #ifdef INET6
 332 {       .pr_type = SOCK_RAW,
 333         .pr_domain = &inetdomain,
 334         .pr_protocol = IPPROTO_IPV6,
 335         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 336         .pr_input = encap4_input,
 337         .pr_output = rip_output,
 338         .pr_ctlinput = rip_ctlinput,
 339         .pr_ctloutput = rip_ctloutput,
 340         .pr_usrreq = rip_usrreq,
 341         .pr_init = encap_init,
 342 },
 343 #endif /* INET6 */
 344 #if NETHERIP > 0
 345 {       .pr_type = SOCK_RAW,
 346         .pr_domain = &inetdomain,
 347         .pr_protocol = IPPROTO_ETHERIP,
 348         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 349         .pr_input = ip_etherip_input,
 350         .pr_output = rip_output,
 351         .pr_ctlinput = rip_ctlinput,
 352         .pr_ctloutput = rip_ctloutput,
 353         .pr_usrreq = rip_usrreq,
 354 },
 355 #endif /* NETHERIP > 0 */
 356 #if NCARP > 0
 357 {       .pr_type = SOCK_RAW,
 358         .pr_domain = &inetdomain,
 359         .pr_protocol = IPPROTO_CARP,
 360         .pr_flags = PR_ATOMIC|PR_ADDR,
 361         .pr_input = carp_proto_input,
 362         .pr_output = rip_output,
 363         .pr_ctloutput = rip_ctloutput,
 364         .pr_usrreq = rip_usrreq,
 365         .pr_init = carp_init,
 366 },
 367 #endif /* NCARP > 0 */
 368 #if NPFSYNC > 0
 369 {       .pr_type = SOCK_RAW,
 370         .pr_domain = &inetdomain,
 371         .pr_protocol = IPPROTO_PFSYNC,
 372         .pr_flags        = PR_ATOMIC|PR_ADDR,
 373         .pr_input        = pfsync_input,
 374         .pr_output       = rip_output,
 375         .pr_ctloutput = rip_ctloutput,
 376         .pr_usrreq       = rip_usrreq,
 377 },
 378 #endif /* NPFSYNC > 0 */
 379 {       .pr_type = SOCK_RAW,
 380         .pr_domain = &inetdomain,
 381         .pr_protocol = IPPROTO_IGMP,
 382         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 383         .pr_input = igmp_input,
 384         .pr_output = rip_output,
 385         .pr_ctloutput = rip_ctloutput,
 386         .pr_ctlinput = rip_ctlinput,
 387         .pr_usrreq = rip_usrreq,
 388         .pr_fasttimo = igmp_fasttimo,
 389         .pr_slowtimo = igmp_slowtimo,
 390         .pr_init = igmp_init,
 391 },
 392 #ifdef PIM
 393 {       .pr_type = SOCK_RAW,
 394         .pr_domain = &inetdomain,
 395         .pr_protocol = IPPROTO_PIM,
 396         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 397         .pr_input = pim_input,
 398         .pr_output = rip_output,
 399         .pr_ctloutput = rip_ctloutput,
 400         .pr_ctlinput = rip_ctlinput,
 401         .pr_usrreq = rip_usrreq,
 402 },
 403 #endif /* PIM */
 404 #ifdef TPIP
 405 {       .pr_type = SOCK_SEQPACKET,
 406         .pr_domain = &inetdomain,
 407         .pr_protocol = IPPROTO_TP,
 408         .pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_LISTEN|PR_LASTHDR|PR_ABRTACPTDIS,
 409         .pr_input = tpip_input,
 410         .pr_ctloutput = tp_ctloutput,
 411         .pr_ctlinput = tpip_ctlinput,
 412         .pr_usrreq = tp_usrreq,
 413         .pr_init = tp_init,
 414         .pr_slowtimo = tp_slowtimo,
 415         .pr_drain = tp_drain,
 416 },
 417 #endif /* TPIP */
 418 #ifdef ISO
 419 /* EON (ISO CLNL over IP) */
 420 #ifdef EON
 421 {       .pr_type = SOCK_RAW,
 422         .pr_domain = &inetdomain,
 423         .pr_protocol = IPPROTO_EON,
 424         .pr_flags = PR_LASTHDR,
 425         .pr_input = eoninput,
 426         .pr_ctlinput = eonctlinput,
 427         .pr_init = eonprotoinit,
 428 },
 429 #else
 430 {       .pr_type = SOCK_RAW,
 431         .pr_domain = &inetdomain,
 432         .pr_protocol = IPPROTO_EON,
 433         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 434         .pr_input = encap4_input,
 435         .pr_output = rip_output,
 436         .pr_ctloutput = rip_ctloutput,
 437         .pr_ctlinput = rip_ctlinput,
 438         .pr_usrreq = rip_usrreq,
 439         .pr_init = encap_init,
 440 },
 441 #endif /* EON */
 442 #endif /* ISO */
 443 /* raw wildcard */
 444 {       .pr_type = SOCK_RAW,
 445         .pr_domain = &inetdomain,
 446         .pr_flags = PR_ATOMIC|PR_ADDR|PR_LASTHDR,
 447         .pr_input = rip_input,
 448         .pr_output = rip_output,
 449         .pr_ctloutput = rip_ctloutput,
 450         .pr_ctlinput = rip_ctlinput,
 451         .pr_usrreq = rip_usrreq,
 452         .pr_init = rip_init,
 453 },
 454 };
 455
 456 extern struct ifqueue ipintrq;
 457
 458 const struct sockaddr_in in_any = {
 459           .sin_len = sizeof(struct sockaddr_in)
 460         , .sin_family = AF_INET
 461         , .sin_port = 0
 462         , .sin_addr = {.s_addr = 0 /* INADDR_ANY */}
 463 };
 464
 465 struct domain inetdomain = {
 466         .dom_family = PF_INET, .dom_name = "internet", .dom_init = NULL,
 467         .dom_externalize = NULL, .dom_dispose = NULL,
 468         .dom_protosw = inetsw,
 469         .dom_protoswNPROTOSW = &inetsw[__arraycount(inetsw)],
 470         .dom_rtattach = rn_inithead,
 471         .dom_rtoffset = 32,
 472         .dom_maxrtkey = sizeof(struct ip_pack4),
 473 #ifdef IPSELSRC
 474         .dom_ifattach = in_domifattach,
 475         .dom_ifdetach = in_domifdetach,
 476 #else
 477         .dom_ifattach = NULL,
 478         .dom_ifdetach = NULL,
 479 #endif
 480         .dom_ifqueues = { &ipintrq, NULL },
 481         .dom_link = { NULL },
 482         .dom_mowner = MOWNER_INIT("",""),
 483         .dom_sa_cmpofs = offsetof(struct sockaddr_in, sin_addr),
 484         .dom_sa_cmplen = sizeof(struct in_addr),
 485         .dom_sa_any = (const struct sockaddr *)&in_any,
 486         .dom_sockaddr_const_addr = sockaddr_in_const_addr,
 487         .dom_sockaddr_addr = sockaddr_in_addr,
 488         .dom_rtcache = LIST_HEAD_INITIALIZER(inetdomain.dom_rtcache)
 489 };
 490
 491 u_char  ip_protox[IPPROTO_MAX];
 492
 493 int icmperrppslim = 100;                        /* 100pps */
 494
 495 static void
 496 sockaddr_in_addrlen(const struct sockaddr *sa, socklen_t *slenp)
 497 {
 498         socklen_t slen;
 499
 500         if (slenp == NULL)
 501                 return;
 502
 503         slen = sockaddr_getlen(sa);
 504         *slenp = (socklen_t)MIN(sizeof(struct in_addr),
 505             slen - MIN(slen, offsetof(struct sockaddr_in, sin_addr)));
 506 }
 507
 508 const void *
 509 sockaddr_in_const_addr(const struct sockaddr *sa, socklen_t *slenp)
 510 {
 511         const struct sockaddr_in *sin;
 512
 513         sockaddr_in_addrlen(sa, slenp);
 514         sin = (const struct sockaddr_in *)sa;
 515         return &sin->sin_addr;
 516 }
 517
 518 void *
 519 sockaddr_in_addr(struct sockaddr *sa, socklen_t *slenp)
 520 {
 521         struct sockaddr_in *sin;
 522
 523         sockaddr_in_addrlen(sa, slenp);
 524         sin = (struct sockaddr_in *)sa;
 525         return &sin->sin_addr;
 526 }
 527
 528 int
 529 sockaddr_in_cmp(const struct sockaddr *sa1, const struct sockaddr *sa2)
 530 {
 531         uint_fast8_t len;
 532         const uint_fast8_t addrofs = offsetof(struct sockaddr_in, sin_addr),
 533                            addrend = addrofs + sizeof(struct in_addr);
 534         int rc;
 535         const struct sockaddr_in *sin1, *sin2;
 536
 537         sin1 = satocsin(sa1);
 538         sin2 = satocsin(sa2);
 539
 540         len = MIN(addrend, MIN(sin1->sin_len, sin2->sin_len));
 541
 542         if (len > addrofs &&
 543              (rc = memcmp(&sin1->sin_addr, &sin2->sin_addr,
 544                           len - addrofs)) != 0)
 545                 return rc;
 546
 547         return sin1->sin_len - sin2->sin_len;
 548 }