if_gre.c revision 1.33
1 /* $NetBSD: if_gre.c,v 1.33 2002/06/09 17:32:54 itojun 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 1.33 2002/06/09 17:32:54 itojun Exp $"); 50 51 #include "opt_inet.h" 52 #include "opt_ns.h" 53 #include "bpfilter.h" 54 55 #include <sys/param.h> 56 #include <sys/malloc.h> 57 #include <sys/mbuf.h> 58 #include <sys/proc.h> 59 #include <sys/protosw.h> 60 #include <sys/socket.h> 61 #include <sys/ioctl.h> 62 #include <sys/queue.h> 63 #if __NetBSD__ 64 #include <sys/systm.h> 65 #endif 66 67 #include <machine/cpu.h> 68 69 #include <net/ethertypes.h> 70 #include <net/if.h> 71 #include <net/if_types.h> 72 #include <net/netisr.h> 73 #include <net/route.h> 74 75 #ifdef INET 76 #include <netinet/in.h> 77 #include <netinet/in_systm.h> 78 #include <netinet/in_var.h> 79 #include <netinet/ip.h> 80 #include <netinet/ip_var.h> 81 #else 82 #error "Huh? if_gre without inet?" 83 #endif 84 85 #ifdef NS 86 #include <netns/ns.h> 87 #include <netns/ns_if.h> 88 #endif 89 90 #ifdef NETATALK 91 #include <netatalk/at.h> 92 #include <netatalk/at_var.h> 93 #include <netatalk/at_extern.h> 94 #endif 95 96 #if NBPFILTER > 0 97 #include <sys/time.h> 98 #include <net/bpf.h> 99 #endif 100 101 #include <net/if_gre.h> 102 103 /* 104 * It is not easy to calculate the right value for a GRE MTU. 105 * We leave this task to the admin and use the same default that 106 * other vendors use. 107 */ 108 #define GREMTU 1476 109 #define LINK_MASK (IFF_LINK0|IFF_LINK1|IFF_LINK2) 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 void 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 void greattach __P((int)); 123 124 /* ARGSUSED */ 125 void 126 greattach(count) 127 int count; 128 { 129 130 LIST_INIT(&gre_softc_list); 131 if_clone_attach(&gre_cloner); 132 } 133 134 int 135 gre_clone_create(ifc, unit) 136 struct if_clone *ifc; 137 int unit; 138 { 139 struct gre_softc *sc; 140 141 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 142 memset(sc, 0, sizeof(struct gre_softc)); 143 144 sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); 145 sc->sc_if.if_softc = sc; 146 sc->sc_if.if_type = IFT_OTHER; 147 sc->sc_if.if_addrlen = 4; 148 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 149 sc->sc_if.if_dlt = DLT_NULL; 150 sc->sc_if.if_mtu = GREMTU; 151 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 152 sc->sc_if.if_output = gre_output; 153 sc->sc_if.if_ioctl = gre_ioctl; 154 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 155 sc->g_proto = IPPROTO_GRE; 156 if_attach(&sc->sc_if); 157 if_alloc_sadl(&sc->sc_if); 158 #if NBPFILTER > 0 159 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 160 #endif 161 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 162 return (0); 163 } 164 165 void 166 gre_clone_destroy(ifp) 167 struct ifnet *ifp; 168 { 169 struct gre_softc *sc = ifp->if_softc; 170 171 LIST_REMOVE(sc, sc_list); 172 #if NBPFILTER > 0 173 bpfdetach(ifp); 174 #endif 175 if_detach(ifp); 176 free(sc, M_DEVBUF); 177 } 178 179 /* 180 * The output routine. Takes a packet and encapsulates it in the protocol 181 * given by sc->g_proto. See also RFC 1701 and RFC 2004 182 */ 183 int 184 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 185 struct rtentry *rt) 186 { 187 int error = 0; 188 struct gre_softc *sc = ifp->if_softc; 189 struct greip *gh; 190 struct ip *inp; 191 u_char osrc; 192 u_short etype = 0; 193 struct mobile_h mob_h; 194 195 if ((ifp->if_flags & IFF_UP) == 0) 196 return ENETDOWN; 197 198 gh = NULL; 199 inp = NULL; 200 osrc = 0; 201 202 #if NBPFILTER >0 203 if (ifp->if_bpf) { 204 /* see comment of other if_foo.c files */ 205 struct mbuf m0; 206 u_int32_t af = dst->sa_family; 207 208 m0.m_next = m; 209 m0.m_len = 4; 210 m0.m_data = (char *)⁡ 211 212 bpf_mtap(ifp->if_bpf, &m0); 213 } 214 #endif 215 216 m->m_flags &= ~(M_BCAST|M_MCAST); 217 218 if (sc->g_proto == IPPROTO_MOBILE) { 219 if (dst->sa_family == AF_INET) { 220 struct mbuf *m0; 221 int msiz; 222 223 inp = mtod(m, struct ip *); 224 225 memset(&mob_h, 0, MOB_H_SIZ_L); 226 mob_h.proto = (inp->ip_p) << 8; 227 mob_h.odst = inp->ip_dst.s_addr; 228 inp->ip_dst.s_addr = sc->g_dst.s_addr; 229 230 /* 231 * If the packet comes from our host, we only change 232 * the destination address in the IP header. 233 * Else we also need to save and change the source 234 */ 235 if (in_hosteq(inp->ip_src, sc->g_src)) { 236 msiz = MOB_H_SIZ_S; 237 } else { 238 mob_h.proto |= MOB_H_SBIT; 239 mob_h.osrc = inp->ip_src.s_addr; 240 inp->ip_src.s_addr = sc->g_src.s_addr; 241 msiz = MOB_H_SIZ_L; 242 } 243 HTONS(mob_h.proto); 244 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 245 246 if ((m->m_data - msiz) < m->m_pktdat) { 247 /* need new mbuf */ 248 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 249 if (m0 == NULL) { 250 IF_DROP(&ifp->if_snd); 251 m_freem(m); 252 return (ENOBUFS); 253 } 254 m0->m_next = m; 255 m->m_data += sizeof(struct ip); 256 m->m_len -= sizeof(struct ip); 257 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 258 m0->m_len = msiz + sizeof(struct ip); 259 m0->m_data += max_linkhdr; 260 memcpy(mtod(m0, caddr_t), (caddr_t)inp, 261 sizeof(struct ip)); 262 m = m0; 263 } else { /* we have some space left in the old one */ 264 m->m_data -= msiz; 265 m->m_len += msiz; 266 m->m_pkthdr.len += msiz; 267 memmove(mtod(m, caddr_t), inp, 268 sizeof(struct ip)); 269 } 270 inp=mtod(m, struct ip *); 271 memcpy((caddr_t)(inp + 1), &mob_h, (unsigned)msiz); 272 NTOHS(inp->ip_len); 273 inp->ip_len += msiz; 274 } else { /* AF_INET */ 275 IF_DROP(&ifp->if_snd); 276 m_freem(m); 277 return (EINVAL); 278 } 279 } else if (sc->g_proto == IPPROTO_GRE) { 280 switch (dst->sa_family) { 281 case AF_INET: 282 inp = mtod(m, struct ip *); 283 etype = ETHERTYPE_IP; 284 break; 285 #ifdef NETATALK 286 case AF_APPLETALK: 287 etype = ETHERTYPE_ATALK; 288 break; 289 #endif 290 #ifdef NS 291 case AF_NS: 292 etype = ETHERTYPE_NS; 293 break; 294 #endif 295 default: 296 IF_DROP(&ifp->if_snd); 297 m_freem(m); 298 return (EAFNOSUPPORT); 299 } 300 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 301 } else { 302 error = EINVAL; 303 IF_DROP(&ifp->if_snd); 304 m_freem(m); 305 return (error); 306 } 307 308 if (m == NULL) { 309 IF_DROP(&ifp->if_snd); 310 return (ENOBUFS); 311 } 312 313 gh = mtod(m, struct greip *); 314 if (sc->g_proto == IPPROTO_GRE) { 315 /* we don't have any GRE flags for now */ 316 317 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 318 gh->gi_ptype = htons(etype); 319 } 320 321 gh->gi_pr = sc->g_proto; 322 if (sc->g_proto != IPPROTO_MOBILE) { 323 gh->gi_src = sc->g_src; 324 gh->gi_dst = sc->g_dst; 325 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 326 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 327 ((struct ip*)gh)->ip_tos = inp->ip_tos; 328 gh->gi_len = m->m_pkthdr.len; 329 } 330 331 ifp->if_opackets++; 332 ifp->if_obytes += m->m_pkthdr.len; 333 /* send it off */ 334 error = ip_output(m, NULL, &sc->route, 0, NULL); 335 if (error) 336 ifp->if_oerrors++; 337 return (error); 338 } 339 340 int 341 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 342 { 343 struct proc *p = curproc; /* XXX */ 344 struct ifaddr *ifa = (struct ifaddr *)data; 345 struct ifreq *ifr = (struct ifreq *)data; 346 struct in_ifaddr *ia = (struct in_ifaddr *)data; 347 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 348 struct gre_softc *sc = ifp->if_softc; 349 int s; 350 struct sockaddr_in si; 351 struct sockaddr *sa = NULL; 352 int error; 353 354 error = 0; 355 356 s = splnet(); 357 switch (cmd) { 358 case SIOCSIFADDR: 359 case SIOCSIFDSTADDR: 360 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 361 break; 362 /* 363 * set tunnel endpoints in case that we "only" 364 * have ip over ip encapsulation. This allows to 365 * set tunnel endpoints with ifconfig. 366 */ 367 if (ifa->ifa_addr->sa_family == AF_INET) { 368 sa = ifa->ifa_addr; 369 sc->g_src = (satosin(sa))->sin_addr; 370 sc->g_dst = ia->ia_dstaddr.sin_addr; 371 if ((sc->g_src.s_addr != INADDR_ANY) && 372 (sc->g_dst.s_addr != INADDR_ANY)) { 373 if (sc->route.ro_rt != 0) /* free old route */ 374 RTFREE(sc->route.ro_rt); 375 if (gre_compute_route(sc) == 0) 376 ifp->if_flags |= IFF_UP; 377 } 378 } 379 break; 380 case SIOCSIFFLAGS: 381 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 382 break; 383 if ((sc->g_dst.s_addr == INADDR_ANY) || 384 (sc->g_src.s_addr == INADDR_ANY)) 385 ifp->if_flags &= ~IFF_UP; 386 387 switch (ifr->ifr_flags & LINK_MASK) { 388 case IFF_LINK0: 389 sc->g_proto = IPPROTO_GRE; 390 ifp->if_flags |= IFF_LINK0; 391 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 392 break; 393 case IFF_LINK2: 394 sc->g_proto = IPPROTO_MOBILE; 395 ifp->if_flags |= IFF_LINK2; 396 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1); 397 break; 398 } 399 break; 400 case SIOCSIFMTU: 401 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 402 break; 403 if (ifr->ifr_mtu < 576) { 404 error = EINVAL; 405 break; 406 } 407 ifp->if_mtu = ifr->ifr_mtu; 408 break; 409 case SIOCGIFMTU: 410 ifr->ifr_mtu = sc->sc_if.if_mtu; 411 break; 412 case SIOCADDMULTI: 413 case SIOCDELMULTI: 414 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 415 break; 416 if (ifr == 0) { 417 error = EAFNOSUPPORT; 418 break; 419 } 420 switch (ifr->ifr_addr.sa_family) { 421 #ifdef INET 422 case AF_INET: 423 break; 424 #endif 425 default: 426 error = EAFNOSUPPORT; 427 break; 428 } 429 break; 430 case GRESPROTO: 431 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 432 break; 433 sc->g_proto = ifr->ifr_flags; 434 switch (sc->g_proto) { 435 case IPPROTO_GRE : 436 ifp->if_flags |= IFF_LINK0; 437 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 438 break; 439 case IPPROTO_MOBILE : 440 ifp->if_flags |= IFF_LINK2; 441 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 442 break; 443 default: 444 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1|IFF_LINK2); 445 } 446 break; 447 case GREGPROTO: 448 ifr->ifr_flags = sc->g_proto; 449 break; 450 case GRESADDRS: 451 case GRESADDRD: 452 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 453 break; 454 /* 455 * set tunnel endpoints, compute a less specific route 456 * to the remote end and mark if as up 457 */ 458 sa = &ifr->ifr_addr; 459 if (cmd == GRESADDRS) 460 sc->g_src = (satosin(sa))->sin_addr; 461 if (cmd == GRESADDRD) 462 sc->g_dst = (satosin(sa))->sin_addr; 463 recompute: 464 if ((sc->g_src.s_addr != INADDR_ANY) && 465 (sc->g_dst.s_addr != INADDR_ANY)) { 466 if (sc->route.ro_rt != 0) /* free old route */ 467 RTFREE(sc->route.ro_rt); 468 if (gre_compute_route(sc) == 0) 469 ifp->if_flags |= IFF_UP; 470 } 471 break; 472 case GREGADDRS: 473 memset(&si, 0, sizeof(si)); 474 si.sin_family = AF_INET; 475 si.sin_len = sizeof(struct sockaddr_in); 476 si.sin_addr.s_addr = sc->g_src.s_addr; 477 sa = sintosa(&si); 478 ifr->ifr_addr = *sa; 479 break; 480 case GREGADDRD: 481 memset(&si, 0, sizeof(si)); 482 si.sin_family = AF_INET; 483 si.sin_len = sizeof(struct sockaddr_in); 484 si.sin_addr.s_addr = sc->g_dst.s_addr; 485 sa = sintosa(&si); 486 ifr->ifr_addr = *sa; 487 break; 488 case SIOCSLIFPHYADDR: 489 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 490 break; 491 if (lifr->addr.ss_family != AF_INET || 492 lifr->dstaddr.ss_family != AF_INET) { 493 error = EAFNOSUPPORT; 494 break; 495 } 496 if (lifr->addr.ss_len != sizeof(si) || 497 lifr->dstaddr.ss_len != sizeof(si)) { 498 error = EINVAL; 499 break; 500 } 501 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 502 sc->g_dst = 503 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 504 goto recompute; 505 case SIOCDIFPHYADDR: 506 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 507 break; 508 sc->g_src.s_addr = INADDR_ANY; 509 sc->g_dst.s_addr = INADDR_ANY; 510 break; 511 case SIOCGLIFPHYADDR: 512 if (sc->g_src.s_addr == INADDR_ANY || 513 sc->g_dst.s_addr == INADDR_ANY) { 514 error = EADDRNOTAVAIL; 515 break; 516 } 517 memset(&si, 0, sizeof(si)); 518 si.sin_family = AF_INET; 519 si.sin_len = sizeof(struct sockaddr_in); 520 si.sin_addr.s_addr = sc->g_src.s_addr; 521 memcpy(&lifr->addr, &si, sizeof(si)); 522 si.sin_addr.s_addr = sc->g_dst.s_addr; 523 memcpy(&lifr->dstaddr, &si, sizeof(si)); 524 break; 525 default: 526 error = EINVAL; 527 break; 528 } 529 530 splx(s); 531 return (error); 532 } 533 534 /* 535 * computes a route to our destination that is not the one 536 * which would be taken by ip_output(), as this one will loop back to 537 * us. If the interface is p2p as a--->b, then a routing entry exists 538 * If we now send a packet to b (e.g. ping b), this will come down here 539 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 540 * if_gre. 541 * Goal here is to compute a route to b that is less specific than 542 * a-->b. We know that this one exists as in normal operation we have 543 * at least a default route which matches. 544 */ 545 int 546 gre_compute_route(struct gre_softc *sc) 547 { 548 struct route *ro; 549 u_int32_t a, b, c; 550 551 ro = &sc->route; 552 553 memset(ro, 0, sizeof(struct route)); 554 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 555 ro->ro_dst.sa_family = AF_INET; 556 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 557 558 /* 559 * toggle last bit, so our interface is not found, but a less 560 * specific route. I'd rather like to specify a shorter mask, 561 * but this is not possible. Should work though. XXX 562 * there is a simpler way ... 563 */ 564 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 565 a = ntohl(sc->g_dst.s_addr); 566 b = a & 0x01; 567 c = a & 0xfffffffe; 568 b = b ^ 0x01; 569 a = b | c; 570 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 571 = htonl(a); 572 } 573 574 #ifdef DIAGNOSTIC 575 printf("%s: searching a route to %s", sc->sc_if.if_xname, 576 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 577 #endif 578 579 rtalloc(ro); 580 581 /* 582 * check if this returned a route at all and this route is no 583 * recursion to ourself 584 */ 585 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 586 #ifdef DIAGNOSTIC 587 if (ro->ro_rt == NULL) 588 printf(" - no route found!\n"); 589 else 590 printf(" - route loops back to ourself!\n"); 591 #endif 592 return EADDRNOTAVAIL; 593 } 594 595 /* 596 * now change it back - else ip_output will just drop 597 * the route and search one to this interface ... 598 */ 599 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 600 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 601 602 #ifdef DIAGNOSTIC 603 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 604 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 605 printf("\n"); 606 #endif 607 608 return 0; 609 } 610 611 /* 612 * do a checksum of a buffer - much like in_cksum, which operates on 613 * mbufs. 614 */ 615 u_short 616 gre_in_cksum(u_short *p, u_int len) 617 { 618 u_int sum = 0; 619 int nwords = len >> 1; 620 621 while (nwords-- != 0) 622 sum += *p++; 623 624 if (len & 1) { 625 union { 626 u_short w; 627 u_char c[2]; 628 } u; 629 u.c[0] = *(u_char *)p; 630 u.c[1] = 0; 631 sum += u.w; 632 } 633 634 /* end-around-carry */ 635 sum = (sum >> 16) + (sum & 0xffff); 636 sum += (sum >> 16); 637 return (~sum); 638 } 639
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