if_gre.c revision 1.55
1 /* $NetBSD: if_gre.c,v 1.55 2005/02/26 22:45:09 perry 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 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Encapsulate L3 protocols into IP 41 * See RFC 1701 and 1702 for more details. 42 * If_gre is compatible with Cisco GRE tunnels, so you can 43 * have a NetBSD box as the other end of a tunnel interface of a Cisco 44 * router. See gre(4) for more details. 45 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 46 */ 47 48 #include <sys/cdefs.h> 49 __KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.55 2005/02/26 22:45:09 perry Exp $"); 50 51 #include "opt_inet.h" 52 #include "opt_ns.h" 53 #include "bpfilter.h" 54 55 #ifdef INET 56 #include <sys/param.h> 57 #include <sys/malloc.h> 58 #include <sys/mbuf.h> 59 #include <sys/proc.h> 60 #include <sys/protosw.h> 61 #include <sys/socket.h> 62 #include <sys/ioctl.h> 63 #include <sys/queue.h> 64 #if __NetBSD__ 65 #include <sys/systm.h> 66 #endif 67 68 #include <machine/cpu.h> 69 70 #include <net/ethertypes.h> 71 #include <net/if.h> 72 #include <net/if_types.h> 73 #include <net/netisr.h> 74 #include <net/route.h> 75 76 #ifdef INET 77 #include <netinet/in.h> 78 #include <netinet/in_systm.h> 79 #include <netinet/in_var.h> 80 #include <netinet/ip.h> 81 #include <netinet/ip_var.h> 82 #else 83 #error "Huh? if_gre without inet?" 84 #endif 85 86 #ifdef NS 87 #include <netns/ns.h> 88 #include <netns/ns_if.h> 89 #endif 90 91 #ifdef NETATALK 92 #include <netatalk/at.h> 93 #include <netatalk/at_var.h> 94 #include <netatalk/at_extern.h> 95 #endif 96 97 #if NBPFILTER > 0 98 #include <sys/time.h> 99 #include <net/bpf.h> 100 #endif 101 102 #include <net/if_gre.h> 103 104 /* 105 * It is not easy to calculate the right value for a GRE MTU. 106 * We leave this task to the admin and use the same default that 107 * other vendors use. 108 */ 109 #define GREMTU 1476 110 111 struct gre_softc_head gre_softc_list; 112 int ip_gre_ttl = GRE_TTL; 113 114 int gre_clone_create __P((struct if_clone *, int)); 115 int gre_clone_destroy __P((struct ifnet *)); 116 117 struct if_clone gre_cloner = 118 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 119 120 int gre_compute_route(struct gre_softc *sc); 121 122 int 123 gre_clone_create(ifc, unit) 124 struct if_clone *ifc; 125 int unit; 126 { 127 struct gre_softc *sc; 128 129 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 130 memset(sc, 0, sizeof(struct gre_softc)); 131 132 snprintf(sc->sc_if.if_xname, sizeof(sc->sc_if.if_xname), "%s%d", 133 ifc->ifc_name, unit); 134 sc->sc_if.if_softc = sc; 135 sc->sc_if.if_type = IFT_TUNNEL; 136 sc->sc_if.if_addrlen = 0; 137 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 138 sc->sc_if.if_dlt = DLT_NULL; 139 sc->sc_if.if_mtu = GREMTU; 140 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 141 sc->sc_if.if_output = gre_output; 142 sc->sc_if.if_ioctl = gre_ioctl; 143 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 144 sc->g_proto = IPPROTO_GRE; 145 sc->sc_if.if_flags |= IFF_LINK0; 146 if_attach(&sc->sc_if); 147 if_alloc_sadl(&sc->sc_if); 148 #if NBPFILTER > 0 149 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 150 #endif 151 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 152 return (0); 153 } 154 155 int 156 gre_clone_destroy(ifp) 157 struct ifnet *ifp; 158 { 159 struct gre_softc *sc = ifp->if_softc; 160 161 LIST_REMOVE(sc, sc_list); 162 #if NBPFILTER > 0 163 bpfdetach(ifp); 164 #endif 165 if_detach(ifp); 166 free(sc, M_DEVBUF); 167 168 return (0); 169 } 170 171 /* 172 * The output routine. Takes a packet and encapsulates it in the protocol 173 * given by sc->g_proto. See also RFC 1701 and RFC 2004 174 */ 175 int 176 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 177 struct rtentry *rt) 178 { 179 int error = 0; 180 struct gre_softc *sc = ifp->if_softc; 181 struct greip *gh; 182 struct ip *ip; 183 u_int16_t etype = 0; 184 struct mobile_h mob_h; 185 186 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 187 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 188 m_freem(m); 189 error = ENETDOWN; 190 goto end; 191 } 192 193 gh = NULL; 194 ip = NULL; 195 196 #if NBPFILTER >0 197 if (ifp->if_bpf) 198 bpf_mtap_af(ifp->if_bpf, dst->sa_family, m); 199 #endif 200 201 m->m_flags &= ~(M_BCAST|M_MCAST); 202 203 if (sc->g_proto == IPPROTO_MOBILE) { 204 if (dst->sa_family == AF_INET) { 205 struct mbuf *m0; 206 int msiz; 207 208 ip = mtod(m, struct ip *); 209 210 memset(&mob_h, 0, MOB_H_SIZ_L); 211 mob_h.proto = (ip->ip_p) << 8; 212 mob_h.odst = ip->ip_dst.s_addr; 213 ip->ip_dst.s_addr = sc->g_dst.s_addr; 214 215 /* 216 * If the packet comes from our host, we only change 217 * the destination address in the IP header. 218 * Else we also need to save and change the source 219 */ 220 if (in_hosteq(ip->ip_src, sc->g_src)) { 221 msiz = MOB_H_SIZ_S; 222 } else { 223 mob_h.proto |= MOB_H_SBIT; 224 mob_h.osrc = ip->ip_src.s_addr; 225 ip->ip_src.s_addr = sc->g_src.s_addr; 226 msiz = MOB_H_SIZ_L; 227 } 228 HTONS(mob_h.proto); 229 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 230 231 if ((m->m_data - msiz) < m->m_pktdat) { 232 /* need new mbuf */ 233 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 234 if (m0 == NULL) { 235 IF_DROP(&ifp->if_snd); 236 m_freem(m); 237 error = ENOBUFS; 238 goto end; 239 } 240 m0->m_next = m; 241 m->m_data += sizeof(struct ip); 242 m->m_len -= sizeof(struct ip); 243 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 244 m0->m_len = msiz + sizeof(struct ip); 245 m0->m_data += max_linkhdr; 246 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 247 sizeof(struct ip)); 248 m = m0; 249 } else { /* we have some space left in the old one */ 250 m->m_data -= msiz; 251 m->m_len += msiz; 252 m->m_pkthdr.len += msiz; 253 memmove(mtod(m, caddr_t), ip, 254 sizeof(struct ip)); 255 } 256 ip = mtod(m, struct ip *); 257 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 258 ip->ip_len = htons(ntohs(ip->ip_len) + msiz); 259 } else { /* AF_INET */ 260 IF_DROP(&ifp->if_snd); 261 m_freem(m); 262 error = EINVAL; 263 goto end; 264 } 265 } else if (sc->g_proto == IPPROTO_GRE) { 266 switch (dst->sa_family) { 267 case AF_INET: 268 ip = mtod(m, struct ip *); 269 etype = ETHERTYPE_IP; 270 break; 271 #ifdef NETATALK 272 case AF_APPLETALK: 273 etype = ETHERTYPE_ATALK; 274 break; 275 #endif 276 #ifdef NS 277 case AF_NS: 278 etype = ETHERTYPE_NS; 279 break; 280 #endif 281 default: 282 IF_DROP(&ifp->if_snd); 283 m_freem(m); 284 error = EAFNOSUPPORT; 285 goto end; 286 } 287 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 288 } else { 289 IF_DROP(&ifp->if_snd); 290 m_freem(m); 291 error = EINVAL; 292 goto end; 293 } 294 295 if (m == NULL) { /* impossible */ 296 IF_DROP(&ifp->if_snd); 297 error = ENOBUFS; 298 goto end; 299 } 300 301 gh = mtod(m, struct greip *); 302 if (sc->g_proto == IPPROTO_GRE) { 303 /* we don't have any GRE flags for now */ 304 305 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 306 gh->gi_ptype = htons(etype); 307 } 308 309 gh->gi_pr = sc->g_proto; 310 if (sc->g_proto != IPPROTO_MOBILE) { 311 gh->gi_src = sc->g_src; 312 gh->gi_dst = sc->g_dst; 313 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 314 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 315 ((struct ip*)gh)->ip_tos = ip->ip_tos; 316 gh->gi_len = htons(m->m_pkthdr.len); 317 } 318 319 ifp->if_opackets++; 320 ifp->if_obytes += m->m_pkthdr.len; 321 /* send it off */ 322 error = ip_output(m, NULL, &sc->route, 0, 323 (struct ip_moptions *)NULL, (struct socket *)NULL); 324 end: 325 if (error) 326 ifp->if_oerrors++; 327 return (error); 328 } 329 330 int 331 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 332 { 333 struct proc *p = curproc; /* XXX */ 334 struct ifreq *ifr = (struct ifreq *)data; 335 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 336 struct gre_softc *sc = ifp->if_softc; 337 int s; 338 struct sockaddr_in si; 339 struct sockaddr *sa = NULL; 340 int error; 341 342 error = 0; 343 344 s = splnet(); 345 switch (cmd) { 346 case SIOCSIFADDR: 347 ifp->if_flags |= IFF_UP; 348 break; 349 case SIOCSIFDSTADDR: 350 break; 351 case SIOCSIFFLAGS: 352 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 353 break; 354 if ((ifr->ifr_flags & IFF_LINK0) != 0) 355 sc->g_proto = IPPROTO_GRE; 356 else 357 sc->g_proto = IPPROTO_MOBILE; 358 break; 359 case SIOCSIFMTU: 360 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 361 break; 362 if (ifr->ifr_mtu < 576) { 363 error = EINVAL; 364 break; 365 } 366 ifp->if_mtu = ifr->ifr_mtu; 367 break; 368 case SIOCGIFMTU: 369 ifr->ifr_mtu = sc->sc_if.if_mtu; 370 break; 371 case SIOCADDMULTI: 372 case SIOCDELMULTI: 373 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 374 break; 375 if (ifr == 0) { 376 error = EAFNOSUPPORT; 377 break; 378 } 379 switch (ifr->ifr_addr.sa_family) { 380 #ifdef INET 381 case AF_INET: 382 break; 383 #endif 384 default: 385 error = EAFNOSUPPORT; 386 break; 387 } 388 break; 389 case GRESPROTO: 390 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 391 break; 392 sc->g_proto = ifr->ifr_flags; 393 switch (sc->g_proto) { 394 case IPPROTO_GRE: 395 ifp->if_flags |= IFF_LINK0; 396 break; 397 case IPPROTO_MOBILE: 398 ifp->if_flags &= ~IFF_LINK0; 399 break; 400 default: 401 error = EPROTONOSUPPORT; 402 break; 403 } 404 break; 405 case GREGPROTO: 406 ifr->ifr_flags = sc->g_proto; 407 break; 408 case GRESADDRS: 409 case GRESADDRD: 410 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 411 break; 412 /* 413 * set tunnel endpoints, compute a less specific route 414 * to the remote end and mark if as up 415 */ 416 sa = &ifr->ifr_addr; 417 if (cmd == GRESADDRS) 418 sc->g_src = (satosin(sa))->sin_addr; 419 if (cmd == GRESADDRD) 420 sc->g_dst = (satosin(sa))->sin_addr; 421 recompute: 422 if ((sc->g_src.s_addr != INADDR_ANY) && 423 (sc->g_dst.s_addr != INADDR_ANY)) { 424 if (sc->route.ro_rt != 0) /* free old route */ 425 RTFREE(sc->route.ro_rt); 426 if (gre_compute_route(sc) == 0) 427 ifp->if_flags |= IFF_RUNNING; 428 else 429 ifp->if_flags &= ~IFF_RUNNING; 430 } 431 break; 432 case GREGADDRS: 433 memset(&si, 0, sizeof(si)); 434 si.sin_family = AF_INET; 435 si.sin_len = sizeof(struct sockaddr_in); 436 si.sin_addr.s_addr = sc->g_src.s_addr; 437 sa = sintosa(&si); 438 ifr->ifr_addr = *sa; 439 break; 440 case GREGADDRD: 441 memset(&si, 0, sizeof(si)); 442 si.sin_family = AF_INET; 443 si.sin_len = sizeof(struct sockaddr_in); 444 si.sin_addr.s_addr = sc->g_dst.s_addr; 445 sa = sintosa(&si); 446 ifr->ifr_addr = *sa; 447 break; 448 case SIOCSLIFPHYADDR: 449 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 450 break; 451 if (lifr->addr.ss_family != AF_INET || 452 lifr->dstaddr.ss_family != AF_INET) { 453 error = EAFNOSUPPORT; 454 break; 455 } 456 if (lifr->addr.ss_len != sizeof(si) || 457 lifr->dstaddr.ss_len != sizeof(si)) { 458 error = EINVAL; 459 break; 460 } 461 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 462 sc->g_dst = 463 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 464 goto recompute; 465 case SIOCDIFPHYADDR: 466 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 467 break; 468 sc->g_src.s_addr = INADDR_ANY; 469 sc->g_dst.s_addr = INADDR_ANY; 470 break; 471 case SIOCGLIFPHYADDR: 472 if (sc->g_src.s_addr == INADDR_ANY || 473 sc->g_dst.s_addr == INADDR_ANY) { 474 error = EADDRNOTAVAIL; 475 break; 476 } 477 memset(&si, 0, sizeof(si)); 478 si.sin_family = AF_INET; 479 si.sin_len = sizeof(struct sockaddr_in); 480 si.sin_addr.s_addr = sc->g_src.s_addr; 481 memcpy(&lifr->addr, &si, sizeof(si)); 482 si.sin_addr.s_addr = sc->g_dst.s_addr; 483 memcpy(&lifr->dstaddr, &si, sizeof(si)); 484 break; 485 default: 486 error = EINVAL; 487 break; 488 } 489 490 splx(s); 491 return (error); 492 } 493 494 /* 495 * computes a route to our destination that is not the one 496 * which would be taken by ip_output(), as this one will loop back to 497 * us. If the interface is p2p as a--->b, then a routing entry exists 498 * If we now send a packet to b (e.g. ping b), this will come down here 499 * gets src=a, dst=b tacked on and would from ip_output() sent back to 500 * if_gre. 501 * Goal here is to compute a route to b that is less specific than 502 * a-->b. We know that this one exists as in normal operation we have 503 * at least a default route which matches. 504 */ 505 int 506 gre_compute_route(struct gre_softc *sc) 507 { 508 struct route *ro; 509 u_int32_t a, b, c; 510 511 ro = &sc->route; 512 513 memset(ro, 0, sizeof(struct route)); 514 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 515 ro->ro_dst.sa_family = AF_INET; 516 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 517 518 /* 519 * toggle last bit, so our interface is not found, but a less 520 * specific route. I'd rather like to specify a shorter mask, 521 * but this is not possible. Should work though. XXX 522 * there is a simpler way ... 523 */ 524 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 525 a = ntohl(sc->g_dst.s_addr); 526 b = a & 0x01; 527 c = a & 0xfffffffe; 528 b = b ^ 0x01; 529 a = b | c; 530 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 531 = htonl(a); 532 } 533 534 #ifdef DIAGNOSTIC 535 printf("%s: searching for a route to %s", sc->sc_if.if_xname, 536 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 537 #endif 538 539 rtalloc(ro); 540 541 /* 542 * check if this returned a route at all and this route is no 543 * recursion to ourself 544 */ 545 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 546 #ifdef DIAGNOSTIC 547 if (ro->ro_rt == NULL) 548 printf(" - no route found!\n"); 549 else 550 printf(" - route loops back to ourself!\n"); 551 #endif 552 return EADDRNOTAVAIL; 553 } 554 555 /* 556 * now change it back - else ip_output will just drop 557 * the route and search one to this interface ... 558 */ 559 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 560 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 561 562 #ifdef DIAGNOSTIC 563 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 564 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 565 printf("\n"); 566 #endif 567 568 return 0; 569 } 570 571 /* 572 * do a checksum of a buffer - much like in_cksum, which operates on 573 * mbufs. 574 */ 575 u_int16_t 576 gre_in_cksum(u_int16_t *p, u_int len) 577 { 578 u_int32_t sum = 0; 579 int nwords = len >> 1; 580 581 while (nwords-- != 0) 582 sum += *p++; 583 584 if (len & 1) { 585 union { 586 u_short w; 587 u_char c[2]; 588 } u; 589 u.c[0] = *(u_char *)p; 590 u.c[1] = 0; 591 sum += u.w; 592 } 593 594 /* end-around-carry */ 595 sum = (sum >> 16) + (sum & 0xffff); 596 sum += (sum >> 16); 597 return (~sum); 598 } 599 #endif 600 601 void greattach __P((int)); 602 603 /* ARGSUSED */ 604 void 605 greattach(count) 606 int count; 607 { 608 #ifdef INET 609 LIST_INIT(&gre_softc_list); 610 if_clone_attach(&gre_cloner); 611 #endif 612 } 613
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