if_gre.c revision 1.42
1 /* $NetBSD: if_gre.c,v 1.42 2002/08/14 00:23:27 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 1.42 2002/08/14 00:23:27 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 109 110 struct gre_softc_head gre_softc_list; 111 int ip_gre_ttl = GRE_TTL; 112 113 int gre_clone_create __P((struct if_clone *, int)); 114 void gre_clone_destroy __P((struct ifnet *)); 115 116 struct if_clone gre_cloner = 117 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 118 119 int gre_compute_route(struct gre_softc *sc); 120 121 void greattach __P((int)); 122 123 /* ARGSUSED */ 124 void 125 greattach(count) 126 int count; 127 { 128 129 LIST_INIT(&gre_softc_list); 130 if_clone_attach(&gre_cloner); 131 } 132 133 int 134 gre_clone_create(ifc, unit) 135 struct if_clone *ifc; 136 int unit; 137 { 138 struct gre_softc *sc; 139 140 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 141 memset(sc, 0, sizeof(struct gre_softc)); 142 143 sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); 144 sc->sc_if.if_softc = sc; 145 sc->sc_if.if_type = IFT_OTHER; 146 sc->sc_if.if_addrlen = 0; 147 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 148 sc->sc_if.if_dlt = DLT_NULL; 149 sc->sc_if.if_mtu = GREMTU; 150 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 151 sc->sc_if.if_output = gre_output; 152 sc->sc_if.if_ioctl = gre_ioctl; 153 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 154 sc->g_proto = IPPROTO_GRE; 155 sc->sc_if.if_flags |= IFF_LINK0; 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 *ip; 191 u_char osrc; 192 u_short etype = 0; 193 struct mobile_h mob_h; 194 195 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 196 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 197 m_freem(m); 198 error = ENETDOWN; 199 goto end; 200 } 201 202 gh = NULL; 203 ip = NULL; 204 osrc = 0; 205 206 #if NBPFILTER >0 207 if (ifp->if_bpf) { 208 /* see comment of other if_foo.c files */ 209 struct mbuf m0; 210 u_int32_t af = dst->sa_family; 211 212 m0.m_next = m; 213 m0.m_len = 4; 214 m0.m_data = (char *)⁡ 215 216 bpf_mtap(ifp->if_bpf, &m0); 217 } 218 #endif 219 220 m->m_flags &= ~(M_BCAST|M_MCAST); 221 222 if (sc->g_proto == IPPROTO_MOBILE) { 223 if (dst->sa_family == AF_INET) { 224 struct mbuf *m0; 225 int msiz; 226 227 ip = mtod(m, struct ip *); 228 229 memset(&mob_h, 0, MOB_H_SIZ_L); 230 mob_h.proto = (ip->ip_p) << 8; 231 mob_h.odst = ip->ip_dst.s_addr; 232 ip->ip_dst.s_addr = sc->g_dst.s_addr; 233 234 /* 235 * If the packet comes from our host, we only change 236 * the destination address in the IP header. 237 * Else we also need to save and change the source 238 */ 239 if (in_hosteq(ip->ip_src, sc->g_src)) { 240 msiz = MOB_H_SIZ_S; 241 } else { 242 mob_h.proto |= MOB_H_SBIT; 243 mob_h.osrc = ip->ip_src.s_addr; 244 ip->ip_src.s_addr = sc->g_src.s_addr; 245 msiz = MOB_H_SIZ_L; 246 } 247 HTONS(mob_h.proto); 248 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 249 250 if ((m->m_data - msiz) < m->m_pktdat) { 251 /* need new mbuf */ 252 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 253 if (m0 == NULL) { 254 IF_DROP(&ifp->if_snd); 255 m_freem(m); 256 error = ENOBUFS; 257 goto end; 258 } 259 m0->m_next = m; 260 m->m_data += sizeof(struct ip); 261 m->m_len -= sizeof(struct ip); 262 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 263 m0->m_len = msiz + sizeof(struct ip); 264 m0->m_data += max_linkhdr; 265 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 266 sizeof(struct ip)); 267 m = m0; 268 } else { /* we have some space left in the old one */ 269 m->m_data -= msiz; 270 m->m_len += msiz; 271 m->m_pkthdr.len += msiz; 272 memmove(mtod(m, caddr_t), ip, 273 sizeof(struct ip)); 274 } 275 ip = mtod(m, struct ip *); 276 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 277 ip->ip_len = htons(ntohs(ip->ip_len) + msiz); 278 } else { /* AF_INET */ 279 IF_DROP(&ifp->if_snd); 280 m_freem(m); 281 error = EINVAL; 282 goto end; 283 } 284 } else if (sc->g_proto == IPPROTO_GRE) { 285 switch (dst->sa_family) { 286 case AF_INET: 287 ip = mtod(m, struct ip *); 288 etype = ETHERTYPE_IP; 289 break; 290 #ifdef NETATALK 291 case AF_APPLETALK: 292 etype = ETHERTYPE_ATALK; 293 break; 294 #endif 295 #ifdef NS 296 case AF_NS: 297 etype = ETHERTYPE_NS; 298 break; 299 #endif 300 default: 301 IF_DROP(&ifp->if_snd); 302 m_freem(m); 303 error = EAFNOSUPPORT; 304 goto end; 305 } 306 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 307 } else { 308 IF_DROP(&ifp->if_snd); 309 m_freem(m); 310 error = EINVAL; 311 goto end; 312 } 313 314 if (m == NULL) { /* impossible */ 315 IF_DROP(&ifp->if_snd); 316 error = ENOBUFS; 317 goto end; 318 } 319 320 gh = mtod(m, struct greip *); 321 if (sc->g_proto == IPPROTO_GRE) { 322 /* we don't have any GRE flags for now */ 323 324 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 325 gh->gi_ptype = htons(etype); 326 } 327 328 gh->gi_pr = sc->g_proto; 329 if (sc->g_proto != IPPROTO_MOBILE) { 330 gh->gi_src = sc->g_src; 331 gh->gi_dst = sc->g_dst; 332 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 333 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 334 ((struct ip*)gh)->ip_tos = ip->ip_tos; 335 gh->gi_len = m->m_pkthdr.len; 336 } 337 338 ifp->if_opackets++; 339 ifp->if_obytes += m->m_pkthdr.len; 340 /* send it off */ 341 error = ip_output(m, NULL, &sc->route, 0, NULL); 342 end: 343 if (error) 344 ifp->if_oerrors++; 345 return (error); 346 } 347 348 int 349 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 350 { 351 struct proc *p = curproc; /* XXX */ 352 struct ifreq *ifr = (struct ifreq *)data; 353 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 354 struct gre_softc *sc = ifp->if_softc; 355 int s; 356 struct sockaddr_in si; 357 struct sockaddr *sa = NULL; 358 int error; 359 360 error = 0; 361 362 s = splnet(); 363 switch (cmd) { 364 case SIOCSIFADDR: 365 ifp->if_flags |= IFF_UP; 366 break; 367 case SIOCSIFDSTADDR: 368 break; 369 case SIOCSIFFLAGS: 370 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 371 break; 372 if ((ifr->ifr_flags & IFF_LINK0) != 0) 373 sc->g_proto = IPPROTO_GRE; 374 else 375 sc->g_proto = IPPROTO_MOBILE; 376 break; 377 case SIOCSIFMTU: 378 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 379 break; 380 if (ifr->ifr_mtu < 576) { 381 error = EINVAL; 382 break; 383 } 384 ifp->if_mtu = ifr->ifr_mtu; 385 break; 386 case SIOCGIFMTU: 387 ifr->ifr_mtu = sc->sc_if.if_mtu; 388 break; 389 case SIOCADDMULTI: 390 case SIOCDELMULTI: 391 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 392 break; 393 if (ifr == 0) { 394 error = EAFNOSUPPORT; 395 break; 396 } 397 switch (ifr->ifr_addr.sa_family) { 398 #ifdef INET 399 case AF_INET: 400 break; 401 #endif 402 default: 403 error = EAFNOSUPPORT; 404 break; 405 } 406 break; 407 case GRESPROTO: 408 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 409 break; 410 sc->g_proto = ifr->ifr_flags; 411 switch (sc->g_proto) { 412 case IPPROTO_GRE: 413 ifp->if_flags |= IFF_LINK0; 414 break; 415 case IPPROTO_MOBILE: 416 ifp->if_flags &= ~IFF_LINK0; 417 break; 418 default: 419 error = EPROTONOSUPPORT; 420 break; 421 } 422 break; 423 case GREGPROTO: 424 ifr->ifr_flags = sc->g_proto; 425 break; 426 case GRESADDRS: 427 case GRESADDRD: 428 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 429 break; 430 /* 431 * set tunnel endpoints, compute a less specific route 432 * to the remote end and mark if as up 433 */ 434 sa = &ifr->ifr_addr; 435 if (cmd == GRESADDRS) 436 sc->g_src = (satosin(sa))->sin_addr; 437 if (cmd == GRESADDRD) 438 sc->g_dst = (satosin(sa))->sin_addr; 439 recompute: 440 if ((sc->g_src.s_addr != INADDR_ANY) && 441 (sc->g_dst.s_addr != INADDR_ANY)) { 442 if (sc->route.ro_rt != 0) /* free old route */ 443 RTFREE(sc->route.ro_rt); 444 if (gre_compute_route(sc) == 0) 445 ifp->if_flags |= IFF_RUNNING; 446 else 447 ifp->if_flags &= ~IFF_RUNNING; 448 } 449 break; 450 case GREGADDRS: 451 memset(&si, 0, sizeof(si)); 452 si.sin_family = AF_INET; 453 si.sin_len = sizeof(struct sockaddr_in); 454 si.sin_addr.s_addr = sc->g_src.s_addr; 455 sa = sintosa(&si); 456 ifr->ifr_addr = *sa; 457 break; 458 case GREGADDRD: 459 memset(&si, 0, sizeof(si)); 460 si.sin_family = AF_INET; 461 si.sin_len = sizeof(struct sockaddr_in); 462 si.sin_addr.s_addr = sc->g_dst.s_addr; 463 sa = sintosa(&si); 464 ifr->ifr_addr = *sa; 465 break; 466 case SIOCSLIFPHYADDR: 467 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 468 break; 469 if (lifr->addr.ss_family != AF_INET || 470 lifr->dstaddr.ss_family != AF_INET) { 471 error = EAFNOSUPPORT; 472 break; 473 } 474 if (lifr->addr.ss_len != sizeof(si) || 475 lifr->dstaddr.ss_len != sizeof(si)) { 476 error = EINVAL; 477 break; 478 } 479 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 480 sc->g_dst = 481 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 482 goto recompute; 483 case SIOCDIFPHYADDR: 484 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 485 break; 486 sc->g_src.s_addr = INADDR_ANY; 487 sc->g_dst.s_addr = INADDR_ANY; 488 break; 489 case SIOCGLIFPHYADDR: 490 if (sc->g_src.s_addr == INADDR_ANY || 491 sc->g_dst.s_addr == INADDR_ANY) { 492 error = EADDRNOTAVAIL; 493 break; 494 } 495 memset(&si, 0, sizeof(si)); 496 si.sin_family = AF_INET; 497 si.sin_len = sizeof(struct sockaddr_in); 498 si.sin_addr.s_addr = sc->g_src.s_addr; 499 memcpy(&lifr->addr, &si, sizeof(si)); 500 si.sin_addr.s_addr = sc->g_dst.s_addr; 501 memcpy(&lifr->dstaddr, &si, sizeof(si)); 502 break; 503 default: 504 error = EINVAL; 505 break; 506 } 507 508 splx(s); 509 return (error); 510 } 511 512 /* 513 * computes a route to our destination that is not the one 514 * which would be taken by ip_output(), as this one will loop back to 515 * us. If the interface is p2p as a--->b, then a routing entry exists 516 * If we now send a packet to b (e.g. ping b), this will come down here 517 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 518 * if_gre. 519 * Goal here is to compute a route to b that is less specific than 520 * a-->b. We know that this one exists as in normal operation we have 521 * at least a default route which matches. 522 */ 523 int 524 gre_compute_route(struct gre_softc *sc) 525 { 526 struct route *ro; 527 u_int32_t a, b, c; 528 529 ro = &sc->route; 530 531 memset(ro, 0, sizeof(struct route)); 532 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 533 ro->ro_dst.sa_family = AF_INET; 534 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 535 536 /* 537 * toggle last bit, so our interface is not found, but a less 538 * specific route. I'd rather like to specify a shorter mask, 539 * but this is not possible. Should work though. XXX 540 * there is a simpler way ... 541 */ 542 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 543 a = ntohl(sc->g_dst.s_addr); 544 b = a & 0x01; 545 c = a & 0xfffffffe; 546 b = b ^ 0x01; 547 a = b | c; 548 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 549 = htonl(a); 550 } 551 552 #ifdef DIAGNOSTIC 553 printf("%s: searching a route to %s", sc->sc_if.if_xname, 554 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 555 #endif 556 557 rtalloc(ro); 558 559 /* 560 * check if this returned a route at all and this route is no 561 * recursion to ourself 562 */ 563 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 564 #ifdef DIAGNOSTIC 565 if (ro->ro_rt == NULL) 566 printf(" - no route found!\n"); 567 else 568 printf(" - route loops back to ourself!\n"); 569 #endif 570 return EADDRNOTAVAIL; 571 } 572 573 /* 574 * now change it back - else ip_output will just drop 575 * the route and search one to this interface ... 576 */ 577 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 578 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 579 580 #ifdef DIAGNOSTIC 581 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 582 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 583 printf("\n"); 584 #endif 585 586 return 0; 587 } 588 589 /* 590 * do a checksum of a buffer - much like in_cksum, which operates on 591 * mbufs. 592 */ 593 u_short 594 gre_in_cksum(u_short *p, u_int len) 595 { 596 u_int sum = 0; 597 int nwords = len >> 1; 598 599 while (nwords-- != 0) 600 sum += *p++; 601 602 if (len & 1) { 603 union { 604 u_short w; 605 u_char c[2]; 606 } u; 607 u.c[0] = *(u_char *)p; 608 u.c[1] = 0; 609 sum += u.w; 610 } 611 612 /* end-around-carry */ 613 sum = (sum >> 16) + (sum & 0xffff); 614 sum += (sum >> 16); 615 return (~sum); 616 } 617
Indexes created Fri Sep 26 20:09:58 GMT 2025