1 /* $FreeBSD: src/sys/net/if_stf.c,v 1.1.2.11 2003/01/23 21:06:44 sam Exp $ */ 2 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */ 3 4 /* 5 * Copyright (C) 2000 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * 6to4 interface, based on RFC3056. 35 * 36 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting. 37 * There is no address mapping defined from IPv6 multicast address to IPv4 38 * address. Therefore, we do not have IFF_MULTICAST on the interface. 39 * 40 * Due to the lack of address mapping for link-local addresses, we cannot 41 * throw packets toward link-local addresses (fe80::x). Also, we cannot throw 42 * packets to link-local multicast addresses (ff02::x). 43 * 44 * Here are interesting symptoms due to the lack of link-local address: 45 * 46 * Unicast routing exchange: 47 * - RIPng: Impossible. Uses link-local multicast packet toward ff02::9, 48 * and link-local addresses as nexthop. 49 * - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address 50 * assigned to the link, and makes use of them. Also, HELLO packets use 51 * link-local multicast addresses (ff02::5 and ff02::6). 52 * - BGP4+: Maybe. You can only use global address as nexthop, and global 53 * address as TCP endpoint address. 54 * 55 * Multicast routing protocols: 56 * - PIM: Hello packet cannot be used to discover adjacent PIM routers. 57 * Adjacent PIM routers must be configured manually (is it really spec-wise 58 * correct thing to do?). 59 * 60 * ICMPv6: 61 * - Redirects cannot be used due to the lack of link-local address. 62 * 63 * stf interface does not have, and will not need, a link-local address. 64 * It seems to have no real benefit and does not help the above symptoms much. 65 * Even if we assign link-locals to interface, we cannot really 66 * use link-local unicast/multicast on top of 6to4 cloud (since there's no 67 * encapsulation defined for link-local address), and the above analysis does 68 * not change. RFC3056 does not mandate the assignment of link-local address 69 * either. 70 * 71 * 6to4 interface has security issues. Refer to 72 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt 73 * for details. The code tries to filter out some of malicious packets. 74 * Note that there is no way to be 100% secure. 75 */ 76 77 #include "opt_inet.h" 78 #include "opt_inet6.h" 79 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/socket.h> 83 #include <sys/sockio.h> 84 #include <sys/mbuf.h> 85 #include <sys/errno.h> 86 #include <sys/protosw.h> 87 #include <sys/kernel.h> 88 #include <machine/cpu.h> 89 90 #include <sys/malloc.h> 91 92 #include <net/if.h> 93 #include <net/route.h> 94 #include <net/netisr.h> 95 #include <net/if_types.h> 96 #include <net/ifq_var.h> 97 #include "if_stf.h" 98 99 #include <netinet/in.h> 100 #include <netinet/in_systm.h> 101 #include <netinet/ip.h> 102 #include <netinet/ip_var.h> 103 #include <netinet/in_var.h> 104 105 #include <netinet/ip6.h> 106 #include <netinet6/ip6_var.h> 107 #include <netinet6/in6_var.h> 108 #include <netinet/ip_ecn.h> 109 110 #include <netinet/ip_encap.h> 111 112 #include <machine/stdarg.h> 113 114 #include <net/net_osdep.h> 115 116 #include <net/bpf.h> 117 118 #define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002) 119 #define GET_V4(x) ((struct in_addr *)(&(x)->s6_addr16[1])) 120 121 struct stf_softc { 122 struct ifnet sc_if; /* common area */ 123 union { 124 struct route __sc_ro4; 125 struct route_in6 __sc_ro6; /* just for safety */ 126 } __sc_ro46; 127 #define sc_ro __sc_ro46.__sc_ro4 128 const struct encaptab *encap_cookie; 129 }; 130 131 static struct stf_softc *stf; 132 133 static MALLOC_DEFINE(M_STF, "stf", "6to4 Tunnel Interface"); 134 static int ip_stf_ttl = 40; 135 136 extern struct domain inetdomain; 137 struct protosw in_stf_protosw = 138 { 139 .pr_type = SOCK_RAW, 140 .pr_domain = &inetdomain, 141 .pr_protocol = IPPROTO_IPV6, 142 .pr_flags = PR_ATOMIC|PR_ADDR, 143 144 .pr_input = in_stf_input, 145 .pr_output = rip_output, 146 .pr_ctlinput = NULL, 147 .pr_ctloutput = rip_ctloutput, 148 149 .pr_usrreqs = &rip_usrreqs 150 }; 151 152 static int stfmodevent (module_t, int, void *); 153 static int stf_encapcheck (const struct mbuf *, int, int, void *); 154 static struct in6_ifaddr *stf_getsrcifa6 (struct ifnet *); 155 static int stf_output (struct ifnet *, struct mbuf *, struct sockaddr *, 156 struct rtentry *); 157 static int stf_checkaddr4 (struct stf_softc *, struct in_addr *, 158 struct ifnet *); 159 static int stf_checkaddr6 (struct stf_softc *, struct in6_addr *, 160 struct ifnet *); 161 static void stf_rtrequest (int, struct rtentry *); 162 static int stf_ioctl (struct ifnet *, u_long, caddr_t, struct ucred *); 163 164 static int 165 stfmodevent(module_t mod, int type, void *data) 166 { 167 struct stf_softc *sc; 168 int err; 169 const struct encaptab *p; 170 171 switch (type) { 172 case MOD_LOAD: 173 stf = kmalloc(sizeof(struct stf_softc), M_STF, 174 M_WAITOK | M_ZERO); 175 sc = stf; 176 177 bzero(sc, sizeof(*sc)); 178 if_initname(&(sc->sc_if), "stf", 0); 179 180 p = encap_attach_func(AF_INET, IPPROTO_IPV6, stf_encapcheck, 181 (void *)&in_stf_protosw, sc); 182 if (p == NULL) { 183 kprintf("%s: attach failed\n", if_name(&sc->sc_if)); 184 return (ENOMEM); 185 } 186 sc->encap_cookie = p; 187 188 sc->sc_if.if_mtu = IPV6_MMTU; 189 sc->sc_if.if_flags = 0; 190 sc->sc_if.if_ioctl = stf_ioctl; 191 sc->sc_if.if_output = stf_output; 192 sc->sc_if.if_type = IFT_STF; 193 #if 0 194 /* turn off ingress filter */ 195 sc->sc_if.if_flags |= IFF_LINK2; 196 #endif 197 ifq_set_maxlen(&sc->sc_if.if_snd, IFQ_MAXLEN); 198 if_attach(&sc->sc_if, NULL); 199 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int)); 200 break; 201 case MOD_UNLOAD: 202 sc = stf; 203 bpfdetach(&sc->sc_if); 204 if_detach(&sc->sc_if); 205 err = encap_detach(sc->encap_cookie); 206 KASSERT(err == 0, ("Unexpected error detaching encap_cookie")); 207 kfree(sc, M_STF); 208 break; 209 } 210 211 return (0); 212 } 213 214 static moduledata_t stf_mod = { 215 "if_stf", 216 stfmodevent, 217 0 218 }; 219 220 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 221 222 static int 223 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg) 224 { 225 struct ip ip; 226 struct in6_ifaddr *ia6; 227 struct stf_softc *sc; 228 struct in_addr a, b; 229 230 sc = (struct stf_softc *)arg; 231 if (sc == NULL) 232 return 0; 233 234 if ((sc->sc_if.if_flags & IFF_UP) == 0) 235 return 0; 236 237 /* IFF_LINK0 means "no decapsulation" */ 238 if ((sc->sc_if.if_flags & IFF_LINK0) != 0) 239 return 0; 240 241 if (proto != IPPROTO_IPV6) 242 return 0; 243 244 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip); 245 246 if (ip.ip_v != 4) 247 return 0; 248 249 ia6 = stf_getsrcifa6(&sc->sc_if); 250 if (ia6 == NULL) 251 return 0; 252 253 /* 254 * check if IPv4 dst matches the IPv4 address derived from the 255 * local 6to4 address. 256 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:... 257 */ 258 if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst, 259 sizeof(ip.ip_dst)) != 0) 260 return 0; 261 262 /* 263 * check if IPv4 src matches the IPv4 address derived from the 264 * local 6to4 address masked by prefixmask. 265 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24 266 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24 267 */ 268 bzero(&a, sizeof(a)); 269 a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr; 270 a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr; 271 b = ip.ip_src; 272 b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr; 273 if (a.s_addr != b.s_addr) 274 return 0; 275 276 /* stf interface makes single side match only */ 277 return 32; 278 } 279 280 static struct in6_ifaddr * 281 stf_getsrcifa6(struct ifnet *ifp) 282 { 283 struct ifaddr_container *ifac; 284 struct sockaddr_in6 *sin6; 285 struct in_addr in; 286 287 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 288 struct ifaddr *ia = ifac->ifa; 289 struct in_ifaddr_container *iac; 290 291 if (ia->ifa_addr == NULL) 292 continue; 293 if (ia->ifa_addr->sa_family != AF_INET6) 294 continue; 295 sin6 = (struct sockaddr_in6 *)ia->ifa_addr; 296 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) 297 continue; 298 299 bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in)); 300 LIST_FOREACH(iac, INADDR_HASH(in.s_addr), ia_hash) { 301 if (iac->ia->ia_addr.sin_addr.s_addr == in.s_addr) 302 break; 303 } 304 if (iac == NULL) 305 continue; 306 307 return (struct in6_ifaddr *)ia; 308 } 309 310 return NULL; 311 } 312 313 static int 314 stf_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 315 struct rtentry *rt) 316 { 317 struct stf_softc *sc; 318 struct sockaddr_in6 *dst6; 319 struct in_addr *in4; 320 struct sockaddr_in *dst4; 321 u_int8_t tos; 322 struct ip *ip; 323 struct ip6_hdr *ip6; 324 struct in6_ifaddr *ia6; 325 static const uint32_t af = AF_INET6; 326 327 sc = (struct stf_softc*)ifp; 328 dst6 = (struct sockaddr_in6 *)dst; 329 330 /* just in case */ 331 if ((ifp->if_flags & IFF_UP) == 0) { 332 m_freem(m); 333 return ENETDOWN; 334 } 335 336 /* 337 * If we don't have an ip4 address that match my inner ip6 address, 338 * we shouldn't generate output. Without this check, we'll end up 339 * using wrong IPv4 source. 340 */ 341 ia6 = stf_getsrcifa6(ifp); 342 if (ia6 == NULL) { 343 m_freem(m); 344 return ENETDOWN; 345 } 346 347 if (m->m_len < sizeof(*ip6)) { 348 m = m_pullup(m, sizeof(*ip6)); 349 if (!m) 350 return ENOBUFS; 351 } 352 ip6 = mtod(m, struct ip6_hdr *); 353 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 354 355 /* 356 * Pickup the right outer dst addr from the list of candidates. 357 * ip6_dst has priority as it may be able to give us shorter IPv4 hops. 358 */ 359 if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst)) 360 in4 = GET_V4(&ip6->ip6_dst); 361 else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr)) 362 in4 = GET_V4(&dst6->sin6_addr); 363 else { 364 m_freem(m); 365 return ENETUNREACH; 366 } 367 368 if (ifp->if_bpf) { 369 bpf_gettoken(); 370 if (ifp->if_bpf) 371 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 372 bpf_reltoken(); 373 } 374 375 M_PREPEND(m, sizeof(struct ip), M_NOWAIT); 376 if (m && m->m_len < sizeof(struct ip)) 377 m = m_pullup(m, sizeof(struct ip)); 378 if (m == NULL) 379 return ENOBUFS; 380 ip = mtod(m, struct ip *); 381 382 bzero(ip, sizeof(*ip)); 383 384 bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr), 385 &ip->ip_src, sizeof(ip->ip_src)); 386 bcopy(in4, &ip->ip_dst, sizeof(ip->ip_dst)); 387 ip->ip_p = IPPROTO_IPV6; 388 ip->ip_ttl = ip_stf_ttl; 389 ip->ip_len = m->m_pkthdr.len; /*host order*/ 390 if (ifp->if_flags & IFF_LINK1) 391 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos); 392 else 393 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos); 394 395 dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst; 396 if (dst4->sin_family != AF_INET || 397 bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) { 398 /* cache route doesn't match */ 399 dst4->sin_family = AF_INET; 400 dst4->sin_len = sizeof(struct sockaddr_in); 401 bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr)); 402 if (sc->sc_ro.ro_rt) { 403 RTFREE(sc->sc_ro.ro_rt); 404 sc->sc_ro.ro_rt = NULL; 405 } 406 } 407 408 if (sc->sc_ro.ro_rt == NULL) { 409 rtalloc(&sc->sc_ro); 410 if (sc->sc_ro.ro_rt == NULL) { 411 m_freem(m); 412 return ENETUNREACH; 413 } 414 } 415 416 return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL); 417 } 418 419 static int 420 stf_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 421 struct rtentry *rt) 422 { 423 struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd); 424 int error; 425 426 ifsq_serialize_hw(ifsq); 427 error = stf_output_serialized(ifp, m, dst, rt); 428 ifsq_deserialize_hw(ifsq); 429 430 return error; 431 } 432 433 /* 434 * Parameters: 435 * inifp: incoming interface 436 */ 437 static int 438 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp) 439 { 440 struct in_ifaddr_container *iac; 441 442 /* 443 * reject packets with the following address: 444 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8 445 */ 446 if (IN_MULTICAST(ntohl(in->s_addr))) 447 return -1; 448 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) { 449 case 0: case 127: case 255: 450 return -1; 451 } 452 453 /* 454 * reject packets with broadcast 455 */ 456 TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) { 457 struct in_ifaddr *ia4 = iac->ia; 458 459 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 460 continue; 461 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) 462 return -1; 463 } 464 465 /* 466 * perform ingress filter 467 */ 468 if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) { 469 struct sockaddr_in sin; 470 struct rtentry *rt; 471 472 bzero(&sin, sizeof(sin)); 473 sin.sin_family = AF_INET; 474 sin.sin_len = sizeof(struct sockaddr_in); 475 sin.sin_addr = *in; 476 rt = rtpurelookup((struct sockaddr *)&sin); 477 if (!rt || rt->rt_ifp != inifp) { 478 #if 0 479 log(LOG_WARNING, "%s: packet from 0x%x dropped " 480 "due to ingress filter\n", if_name(&sc->sc_if), 481 (u_int32_t)ntohl(sin.sin_addr.s_addr)); 482 #endif 483 if (rt) 484 rtfree(rt); 485 return -1; 486 } 487 rtfree(rt); 488 } 489 490 return 0; 491 } 492 493 /* 494 * Parameters: 495 * inifp: incoming interface 496 */ 497 static int 498 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp) 499 { 500 /* 501 * check 6to4 addresses 502 */ 503 if (IN6_IS_ADDR_6TO4(in6)) 504 return stf_checkaddr4(sc, GET_V4(in6), inifp); 505 506 /* 507 * reject anything that look suspicious. the test is implemented 508 * in ip6_input too, but we check here as well to 509 * (1) reject bad packets earlier, and 510 * (2) to be safe against future ip6_input change. 511 */ 512 if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6)) 513 return -1; 514 515 return 0; 516 } 517 518 int 519 in_stf_input(struct mbuf **mp, int *offp, int proto) 520 { 521 struct mbuf *m; 522 struct stf_softc *sc; 523 struct ip *ip; 524 struct ip6_hdr *ip6; 525 u_int8_t otos, itos; 526 struct ifnet *ifp; 527 int off; 528 static const uint32_t af = AF_INET6; 529 530 m = *mp; 531 off = *offp; 532 533 if (proto != IPPROTO_IPV6) { 534 m_freem(m); 535 return(IPPROTO_DONE); 536 } 537 538 ip = mtod(m, struct ip *); 539 540 sc = (struct stf_softc *)encap_getarg(m); 541 542 if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) { 543 m_freem(m); 544 return(IPPROTO_DONE); 545 } 546 547 ifp = &sc->sc_if; 548 549 /* 550 * perform sanity check against outer src/dst. 551 * for source, perform ingress filter as well. 552 */ 553 if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 || 554 stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) { 555 m_freem(m); 556 return(IPPROTO_DONE); 557 } 558 559 otos = ip->ip_tos; 560 m_adj(m, off); 561 562 if (m->m_len < sizeof(*ip6)) { 563 m = m_pullup(m, sizeof(*ip6)); 564 if (!m) 565 return(IPPROTO_DONE); 566 } 567 ip6 = mtod(m, struct ip6_hdr *); 568 569 /* 570 * perform sanity check against inner src/dst. 571 * for source, perform ingress filter as well. 572 */ 573 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 || 574 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) { 575 m_freem(m); 576 return(IPPROTO_DONE); 577 } 578 579 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 580 if ((ifp->if_flags & IFF_LINK1) != 0) 581 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 582 else 583 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 584 ip6->ip6_flow &= ~htonl(0xff << 20); 585 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 586 587 m->m_pkthdr.rcvif = ifp; 588 589 if (ifp->if_bpf) { 590 bpf_gettoken(); 591 if (ifp->if_bpf) 592 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 593 bpf_reltoken(); 594 } 595 596 /* 597 * Put the packet to the network layer input queue according to the 598 * specified address family. 599 * See net/if_gif.c for possible issues with packet processing 600 * reorder due to extra queueing. 601 */ 602 IFNET_STAT_INC(ifp, ipackets, 1); 603 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len); 604 netisr_queue(NETISR_IPV6, m); 605 return(IPPROTO_DONE); 606 } 607 608 /* ARGSUSED */ 609 static void 610 stf_rtrequest(int cmd, struct rtentry *rt) 611 { 612 613 if (rt) 614 rt->rt_rmx.rmx_mtu = IPV6_MMTU; 615 } 616 617 static int 618 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 619 { 620 struct ifaddr *ifa; 621 struct ifreq *ifr; 622 struct sockaddr_in6 *sin6; 623 int error; 624 625 error = 0; 626 switch (cmd) { 627 case SIOCSIFADDR: 628 ifa = (struct ifaddr *)data; 629 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) { 630 error = EAFNOSUPPORT; 631 break; 632 } 633 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr; 634 if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) { 635 ifa->ifa_rtrequest = stf_rtrequest; 636 ifp->if_flags |= IFF_UP; 637 } else 638 error = EINVAL; 639 break; 640 641 case SIOCADDMULTI: 642 case SIOCDELMULTI: 643 ifr = (struct ifreq *)data; 644 if (ifr && ifr->ifr_addr.sa_family == AF_INET6) 645 ; 646 else 647 error = EAFNOSUPPORT; 648 break; 649 650 default: 651 error = EINVAL; 652 break; 653 } 654 655 return error; 656 } 657