if_gre.c revision 1.59.10.2
1 /* $NetBSD: if_gre.c,v 1.59.10.2 2006/03/10 15:05:22 elad Exp $ */ 2 3 /* 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Heiko W.Rupp <hwr (at) pilhuhn.de> 9 * 10 * IPv6-over-GRE contributed by Gert Doering <gert (at) greenie.muc.de> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 /* 42 * Encapsulate L3 protocols into IP 43 * See RFC 1701 and 1702 for more details. 44 * If_gre is compatible with Cisco GRE tunnels, so you can 45 * have a NetBSD box as the other end of a tunnel interface of a Cisco 46 * router. See gre(4) for more details. 47 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 48 */ 49 50 #include <sys/cdefs.h> 51 __KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.59.10.2 2006/03/10 15:05:22 elad Exp $"); 52 53 #include "opt_inet.h" 54 #include "opt_ns.h" 55 #include "bpfilter.h" 56 57 #ifdef INET 58 #include <sys/param.h> 59 #include <sys/malloc.h> 60 #include <sys/mbuf.h> 61 #include <sys/proc.h> 62 #include <sys/protosw.h> 63 #include <sys/socket.h> 64 #include <sys/ioctl.h> 65 #include <sys/queue.h> 66 #if __NetBSD__ 67 #include <sys/systm.h> 68 #endif 69 70 #include <machine/cpu.h> 71 72 #include <net/ethertypes.h> 73 #include <net/if.h> 74 #include <net/if_types.h> 75 #include <net/netisr.h> 76 #include <net/route.h> 77 78 #ifdef INET 79 #include <netinet/in.h> 80 #include <netinet/in_systm.h> 81 #include <netinet/in_var.h> 82 #include <netinet/ip.h> 83 #include <netinet/ip_var.h> 84 #else 85 #error "Huh? if_gre without inet?" 86 #endif 87 88 #ifdef NS 89 #include <netns/ns.h> 90 #include <netns/ns_if.h> 91 #endif 92 93 #ifdef NETATALK 94 #include <netatalk/at.h> 95 #include <netatalk/at_var.h> 96 #include <netatalk/at_extern.h> 97 #endif 98 99 #if NBPFILTER > 0 100 #include <sys/time.h> 101 #include <net/bpf.h> 102 #endif 103 104 #include <net/if_gre.h> 105 106 /* 107 * It is not easy to calculate the right value for a GRE MTU. 108 * We leave this task to the admin and use the same default that 109 * other vendors use. 110 */ 111 #define GREMTU 1476 112 113 struct gre_softc_head gre_softc_list; 114 int ip_gre_ttl = GRE_TTL; 115 116 static int gre_clone_create(struct if_clone *, int); 117 static int gre_clone_destroy(struct ifnet *); 118 119 static struct if_clone gre_cloner = 120 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 121 122 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 123 struct rtentry *); 124 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 125 126 static int gre_compute_route(struct gre_softc *sc); 127 128 static int 129 gre_clone_create(struct if_clone *ifc, int unit) 130 { 131 struct gre_softc *sc; 132 133 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 134 memset(sc, 0, sizeof(struct gre_softc)); 135 136 snprintf(sc->sc_if.if_xname, sizeof(sc->sc_if.if_xname), "%s%d", 137 ifc->ifc_name, unit); 138 sc->sc_if.if_softc = sc; 139 sc->sc_if.if_type = IFT_TUNNEL; 140 sc->sc_if.if_addrlen = 0; 141 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 142 sc->sc_if.if_dlt = DLT_NULL; 143 sc->sc_if.if_mtu = GREMTU; 144 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 145 sc->sc_if.if_output = gre_output; 146 sc->sc_if.if_ioctl = gre_ioctl; 147 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 148 sc->g_proto = IPPROTO_GRE; 149 sc->sc_if.if_flags |= IFF_LINK0; 150 if_attach(&sc->sc_if); 151 if_alloc_sadl(&sc->sc_if); 152 #if NBPFILTER > 0 153 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 154 #endif 155 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 156 return (0); 157 } 158 159 static int 160 gre_clone_destroy(struct ifnet *ifp) 161 { 162 struct gre_softc *sc = ifp->if_softc; 163 164 LIST_REMOVE(sc, sc_list); 165 #if NBPFILTER > 0 166 bpfdetach(ifp); 167 #endif 168 if_detach(ifp); 169 free(sc, M_DEVBUF); 170 171 return (0); 172 } 173 174 /* 175 * The output routine. Takes a packet and encapsulates it in the protocol 176 * given by sc->g_proto. See also RFC 1701 and RFC 2004 177 */ 178 static int 179 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 180 struct rtentry *rt) 181 { 182 int error = 0; 183 struct gre_softc *sc = ifp->if_softc; 184 struct greip *gh; 185 struct ip *ip; 186 u_int8_t ip_tos = 0; 187 u_int16_t etype = 0; 188 struct mobile_h mob_h; 189 190 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 191 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 192 m_freem(m); 193 error = ENETDOWN; 194 goto end; 195 } 196 197 gh = NULL; 198 ip = NULL; 199 200 #if NBPFILTER >0 201 if (ifp->if_bpf) 202 bpf_mtap_af(ifp->if_bpf, dst->sa_family, m); 203 #endif 204 205 m->m_flags &= ~(M_BCAST|M_MCAST); 206 207 if (sc->g_proto == IPPROTO_MOBILE) { 208 if (dst->sa_family == AF_INET) { 209 struct mbuf *m0; 210 int msiz; 211 212 ip = mtod(m, struct ip *); 213 214 memset(&mob_h, 0, MOB_H_SIZ_L); 215 mob_h.proto = (ip->ip_p) << 8; 216 mob_h.odst = ip->ip_dst.s_addr; 217 ip->ip_dst.s_addr = sc->g_dst.s_addr; 218 219 /* 220 * If the packet comes from our host, we only change 221 * the destination address in the IP header. 222 * Else we also need to save and change the source 223 */ 224 if (in_hosteq(ip->ip_src, sc->g_src)) { 225 msiz = MOB_H_SIZ_S; 226 } else { 227 mob_h.proto |= MOB_H_SBIT; 228 mob_h.osrc = ip->ip_src.s_addr; 229 ip->ip_src.s_addr = sc->g_src.s_addr; 230 msiz = MOB_H_SIZ_L; 231 } 232 HTONS(mob_h.proto); 233 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 234 235 if ((m->m_data - msiz) < m->m_pktdat) { 236 /* need new mbuf */ 237 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 238 if (m0 == NULL) { 239 IF_DROP(&ifp->if_snd); 240 m_freem(m); 241 error = ENOBUFS; 242 goto end; 243 } 244 m0->m_next = m; 245 m->m_data += sizeof(struct ip); 246 m->m_len -= sizeof(struct ip); 247 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 248 m0->m_len = msiz + sizeof(struct ip); 249 m0->m_data += max_linkhdr; 250 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 251 sizeof(struct ip)); 252 m = m0; 253 } else { /* we have some space left in the old one */ 254 m->m_data -= msiz; 255 m->m_len += msiz; 256 m->m_pkthdr.len += msiz; 257 memmove(mtod(m, caddr_t), ip, 258 sizeof(struct ip)); 259 } 260 ip = mtod(m, struct ip *); 261 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 262 ip->ip_len = htons(ntohs(ip->ip_len) + msiz); 263 } else { /* AF_INET */ 264 IF_DROP(&ifp->if_snd); 265 m_freem(m); 266 error = EINVAL; 267 goto end; 268 } 269 } else if (sc->g_proto == IPPROTO_GRE) { 270 #ifdef GRE_DEBUG 271 printf( "start gre_output/GRE, dst->sa_family=%d\n", 272 dst->sa_family ); 273 #endif 274 switch (dst->sa_family) { 275 case AF_INET: 276 ip = mtod(m, struct ip *); 277 ip_tos = ip->ip_tos; 278 etype = ETHERTYPE_IP; 279 break; 280 #ifdef NETATALK 281 case AF_APPLETALK: 282 etype = ETHERTYPE_ATALK; 283 break; 284 #endif 285 #ifdef NS 286 case AF_NS: 287 etype = ETHERTYPE_NS; 288 break; 289 #endif 290 #ifdef INET6 291 case AF_INET6: 292 etype = ETHERTYPE_IPV6; 293 break; 294 #endif 295 default: 296 IF_DROP(&ifp->if_snd); 297 m_freem(m); 298 error = EAFNOSUPPORT; 299 goto end; 300 } 301 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 302 } else { 303 IF_DROP(&ifp->if_snd); 304 m_freem(m); 305 error = EINVAL; 306 goto end; 307 } 308 309 if (m == NULL) { /* impossible */ 310 IF_DROP(&ifp->if_snd); 311 error = ENOBUFS; 312 goto end; 313 } 314 315 gh = mtod(m, struct greip *); 316 if (sc->g_proto == IPPROTO_GRE) { 317 /* we don't have any GRE flags for now */ 318 319 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 320 gh->gi_ptype = htons(etype); 321 } 322 323 gh->gi_pr = sc->g_proto; 324 if (sc->g_proto != IPPROTO_MOBILE) { 325 gh->gi_src = sc->g_src; 326 gh->gi_dst = sc->g_dst; 327 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 328 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 329 ((struct ip*)gh)->ip_tos = ip_tos; 330 gh->gi_len = htons(m->m_pkthdr.len); 331 } 332 333 ifp->if_opackets++; 334 ifp->if_obytes += m->m_pkthdr.len; 335 /* send it off */ 336 error = ip_output(m, NULL, &sc->route, 0, 337 (struct ip_moptions *)NULL, (struct socket *)NULL); 338 end: 339 if (error) 340 ifp->if_oerrors++; 341 return (error); 342 } 343 344 static int 345 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 346 { 347 struct proc *p = curproc; /* XXX */ 348 struct ifreq *ifr = (struct ifreq *)data; 349 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 350 struct gre_softc *sc = ifp->if_softc; 351 int s; 352 struct sockaddr_in si; 353 struct sockaddr *sa = NULL; 354 int error; 355 356 error = 0; 357 358 s = splnet(); 359 switch (cmd) { 360 case SIOCSIFADDR: 361 ifp->if_flags |= IFF_UP; 362 break; 363 case SIOCSIFDSTADDR: 364 break; 365 case SIOCSIFFLAGS: 366 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 367 break; 368 if ((ifr->ifr_flags & IFF_LINK0) != 0) 369 sc->g_proto = IPPROTO_GRE; 370 else 371 sc->g_proto = IPPROTO_MOBILE; 372 break; 373 case SIOCSIFMTU: 374 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 375 break; 376 if (ifr->ifr_mtu < 576) { 377 error = EINVAL; 378 break; 379 } 380 ifp->if_mtu = ifr->ifr_mtu; 381 break; 382 case SIOCGIFMTU: 383 ifr->ifr_mtu = sc->sc_if.if_mtu; 384 break; 385 case SIOCADDMULTI: 386 case SIOCDELMULTI: 387 if (ifr == 0) { 388 error = EAFNOSUPPORT; 389 break; 390 } 391 switch (ifr->ifr_addr.sa_family) { 392 #ifdef INET 393 case AF_INET: 394 break; 395 #endif 396 #ifdef INET6 397 case AF_INET6: 398 break; 399 #endif 400 default: 401 error = EAFNOSUPPORT; 402 break; 403 } 404 break; 405 case GRESPROTO: 406 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 407 break; 408 sc->g_proto = ifr->ifr_flags; 409 switch (sc->g_proto) { 410 case IPPROTO_GRE: 411 ifp->if_flags |= IFF_LINK0; 412 break; 413 case IPPROTO_MOBILE: 414 ifp->if_flags &= ~IFF_LINK0; 415 break; 416 default: 417 error = EPROTONOSUPPORT; 418 break; 419 } 420 break; 421 case GREGPROTO: 422 ifr->ifr_flags = sc->g_proto; 423 break; 424 case GRESADDRS: 425 case GRESADDRD: 426 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 427 break; 428 /* 429 * set tunnel endpoints, compute a less specific route 430 * to the remote end and mark if as up 431 */ 432 sa = &ifr->ifr_addr; 433 if (cmd == GRESADDRS) 434 sc->g_src = (satosin(sa))->sin_addr; 435 if (cmd == GRESADDRD) 436 sc->g_dst = (satosin(sa))->sin_addr; 437 recompute: 438 if ((sc->g_src.s_addr != INADDR_ANY) && 439 (sc->g_dst.s_addr != INADDR_ANY)) { 440 if (sc->route.ro_rt != 0) /* free old route */ 441 RTFREE(sc->route.ro_rt); 442 if (gre_compute_route(sc) == 0) 443 ifp->if_flags |= IFF_RUNNING; 444 else 445 ifp->if_flags &= ~IFF_RUNNING; 446 } 447 break; 448 case GREGADDRS: 449 memset(&si, 0, sizeof(si)); 450 si.sin_family = AF_INET; 451 si.sin_len = sizeof(struct sockaddr_in); 452 si.sin_addr.s_addr = sc->g_src.s_addr; 453 sa = sintosa(&si); 454 ifr->ifr_addr = *sa; 455 break; 456 case GREGADDRD: 457 memset(&si, 0, sizeof(si)); 458 si.sin_family = AF_INET; 459 si.sin_len = sizeof(struct sockaddr_in); 460 si.sin_addr.s_addr = sc->g_dst.s_addr; 461 sa = sintosa(&si); 462 ifr->ifr_addr = *sa; 463 break; 464 case SIOCSLIFPHYADDR: 465 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 466 break; 467 if (lifr->addr.ss_family != AF_INET || 468 lifr->dstaddr.ss_family != AF_INET) { 469 error = EAFNOSUPPORT; 470 break; 471 } 472 if (lifr->addr.ss_len != sizeof(si) || 473 lifr->dstaddr.ss_len != sizeof(si)) { 474 error = EINVAL; 475 break; 476 } 477 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 478 sc->g_dst = 479 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 480 goto recompute; 481 case SIOCDIFPHYADDR: 482 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, &p->p_acflag)) != 0) 483 break; 484 sc->g_src.s_addr = INADDR_ANY; 485 sc->g_dst.s_addr = INADDR_ANY; 486 break; 487 case SIOCGLIFPHYADDR: 488 if (sc->g_src.s_addr == INADDR_ANY || 489 sc->g_dst.s_addr == INADDR_ANY) { 490 error = EADDRNOTAVAIL; 491 break; 492 } 493 memset(&si, 0, sizeof(si)); 494 si.sin_family = AF_INET; 495 si.sin_len = sizeof(struct sockaddr_in); 496 si.sin_addr.s_addr = sc->g_src.s_addr; 497 memcpy(&lifr->addr, &si, sizeof(si)); 498 si.sin_addr.s_addr = sc->g_dst.s_addr; 499 memcpy(&lifr->dstaddr, &si, sizeof(si)); 500 break; 501 default: 502 error = EINVAL; 503 break; 504 } 505 506 splx(s); 507 return (error); 508 } 509 510 /* 511 * computes a route to our destination that is not the one 512 * which would be taken by ip_output(), as this one will loop back to 513 * us. If the interface is p2p as a--->b, then a routing entry exists 514 * If we now send a packet to b (e.g. ping b), this will come down here 515 * gets src=a, dst=b tacked on and would from ip_output() sent back to 516 * if_gre. 517 * Goal here is to compute a route to b that is less specific than 518 * a-->b. We know that this one exists as in normal operation we have 519 * at least a default route which matches. 520 */ 521 static int 522 gre_compute_route(struct gre_softc *sc) 523 { 524 struct route *ro; 525 u_int32_t a, b, c; 526 527 ro = &sc->route; 528 529 memset(ro, 0, sizeof(struct route)); 530 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 531 ro->ro_dst.sa_family = AF_INET; 532 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 533 534 /* 535 * toggle last bit, so our interface is not found, but a less 536 * specific route. I'd rather like to specify a shorter mask, 537 * but this is not possible. Should work though. XXX 538 * there is a simpler way ... 539 */ 540 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 541 a = ntohl(sc->g_dst.s_addr); 542 b = a & 0x01; 543 c = a & 0xfffffffe; 544 b = b ^ 0x01; 545 a = b | c; 546 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 547 = htonl(a); 548 } 549 550 #ifdef DIAGNOSTIC 551 printf("%s: searching for a route to %s", sc->sc_if.if_xname, 552 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 553 #endif 554 555 rtalloc(ro); 556 557 /* 558 * check if this returned a route at all and this route is no 559 * recursion to ourself 560 */ 561 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 562 #ifdef DIAGNOSTIC 563 if (ro->ro_rt == NULL) 564 printf(" - no route found!\n"); 565 else 566 printf(" - route loops back to ourself!\n"); 567 #endif 568 return EADDRNOTAVAIL; 569 } 570 571 /* 572 * now change it back - else ip_output will just drop 573 * the route and search one to this interface ... 574 */ 575 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 576 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 577 578 #ifdef DIAGNOSTIC 579 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 580 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 581 printf("\n"); 582 #endif 583 584 return 0; 585 } 586 587 /* 588 * do a checksum of a buffer - much like in_cksum, which operates on 589 * mbufs. 590 */ 591 u_int16_t 592 gre_in_cksum(u_int16_t *p, u_int len) 593 { 594 u_int32_t sum = 0; 595 int nwords = len >> 1; 596 597 while (nwords-- != 0) 598 sum += *p++; 599 600 if (len & 1) { 601 union { 602 u_short w; 603 u_char c[2]; 604 } u; 605 u.c[0] = *(u_char *)p; 606 u.c[1] = 0; 607 sum += u.w; 608 } 609 610 /* end-around-carry */ 611 sum = (sum >> 16) + (sum & 0xffff); 612 sum += (sum >> 16); 613 return (~sum); 614 } 615 #endif 616 617 void greattach(int); 618 619 /* ARGSUSED */ 620 void 621 greattach(int count) 622 { 623 #ifdef INET 624 LIST_INIT(&gre_softc_list); 625 if_clone_attach(&gre_cloner); 626 #endif 627 } 628
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