if_gre.c revision 1.17.2.5
1 /* $NetBSD: if_gre.c,v 1.17.2.5 2002/02/28 04:15:00 nathanw 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 1.17.2.5 2002/02/28 04:15:00 nathanw 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/lwp.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 * XXX this is below the standard MTU of 106 * 1500 Bytes, allowing for headers, 107 * but we should possibly do path mtu discovery 108 * before changing if state to up to find the 109 * correct value 110 */ 111 #define GREMTU 1450 112 #define LINK_MASK (IFF_LINK0|IFF_LINK1|IFF_LINK2) 113 114 struct gre_softc_head gre_softc_list; 115 int ip_gre_ttl = GRE_TTL; 116 117 int gre_clone_create __P((struct if_clone *, int)); 118 void gre_clone_destroy __P((struct ifnet *)); 119 120 struct if_clone gre_cloner = 121 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 122 123 int gre_compute_route(struct gre_softc *sc); 124 125 void greattach __P((int)); 126 127 /* ARGSUSED */ 128 void 129 greattach(count) 130 int count; 131 { 132 133 LIST_INIT(&gre_softc_list); 134 if_clone_attach(&gre_cloner); 135 } 136 137 int 138 gre_clone_create(ifc, unit) 139 struct if_clone *ifc; 140 int unit; 141 { 142 struct gre_softc *sc; 143 144 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 145 memset(sc, 0, sizeof(struct gre_softc)); 146 147 sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); 148 sc->sc_if.if_softc = sc; 149 sc->sc_if.if_type = IFT_OTHER; 150 sc->sc_if.if_addrlen = 4; 151 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 152 sc->sc_if.if_dlt = DLT_NULL; 153 sc->sc_if.if_mtu = GREMTU; 154 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 155 sc->sc_if.if_output = gre_output; 156 sc->sc_if.if_ioctl = gre_ioctl; 157 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 158 sc->g_proto = IPPROTO_GRE; 159 if_attach(&sc->sc_if); 160 if_alloc_sadl(&sc->sc_if); 161 #if NBPFILTER > 0 162 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 163 #endif 164 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 165 return (0); 166 } 167 168 void 169 gre_clone_destroy(ifp) 170 struct ifnet *ifp; 171 { 172 struct gre_softc *sc = ifp->if_softc; 173 174 LIST_REMOVE(sc, sc_list); 175 #if NBPFILTER > 0 176 bpfdetach(ifp); 177 #endif 178 if_detach(ifp); 179 free(sc, M_DEVBUF); 180 } 181 182 /* 183 * The output routine. Takes a packet and encapsulates it in the protocol 184 * given by sc->g_proto. See also RFC 1701 and RFC 2004 185 */ 186 int 187 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 188 struct rtentry *rt) 189 { 190 int error = 0; 191 struct gre_softc *sc = ifp->if_softc; 192 struct greip *gh; 193 struct ip *inp; 194 u_char osrc; 195 u_short etype = 0; 196 struct mobile_h mob_h; 197 198 if ((ifp->if_flags & IFF_UP) == 0) 199 return ENETDOWN; 200 201 gh = NULL; 202 inp = NULL; 203 osrc = 0; 204 205 #if NBPFILTER >0 206 if (ifp->if_bpf) { 207 /* see comment of other if_foo.c files */ 208 struct mbuf m0; 209 u_int32_t af = dst->sa_family; 210 211 m0.m_next = m; 212 m0.m_len = 4; 213 m0.m_data = (char *)⁡ 214 215 bpf_mtap(ifp->if_bpf, &m0); 216 } 217 #endif 218 219 m->m_flags &= ~(M_BCAST|M_MCAST); 220 221 if (sc->g_proto == IPPROTO_MOBILE) { 222 if (dst->sa_family == AF_INET) { 223 struct mbuf *m0; 224 int msiz; 225 226 inp = mtod(m, struct ip *); 227 228 memset(&mob_h, 0, MOB_H_SIZ_L); 229 mob_h.proto = (inp->ip_p) << 8; 230 mob_h.odst = inp->ip_dst.s_addr; 231 inp->ip_dst.s_addr = sc->g_dst.s_addr; 232 233 /* 234 * If the packet comes from our host, we only change 235 * the destination address in the IP header. 236 * Else we also need to save and change the source 237 */ 238 if (in_hosteq(inp->ip_src, sc->g_src)) { 239 msiz = MOB_H_SIZ_S; 240 } else { 241 mob_h.proto |= MOB_H_SBIT; 242 mob_h.osrc = inp->ip_src.s_addr; 243 inp->ip_src.s_addr = sc->g_src.s_addr; 244 msiz = MOB_H_SIZ_L; 245 } 246 HTONS(mob_h.proto); 247 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 248 249 if ((m->m_data - msiz) < m->m_pktdat) { 250 /* need new mbuf */ 251 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 252 if (m0 == NULL) { 253 IF_DROP(&ifp->if_snd); 254 m_freem(m); 255 return (ENOBUFS); 256 } 257 m0->m_next = m; 258 m->m_data += sizeof(struct ip); 259 m->m_len -= sizeof(struct ip); 260 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 261 m0->m_len = msiz + sizeof(struct ip); 262 m0->m_data += max_linkhdr; 263 memcpy(mtod(m0, caddr_t), (caddr_t)inp, 264 sizeof(struct ip)); 265 m = m0; 266 } else { /* we have some space left in the old one */ 267 m->m_data -= msiz; 268 m->m_len += msiz; 269 m->m_pkthdr.len += msiz; 270 memmove(mtod(m, caddr_t), inp, 271 sizeof(struct ip)); 272 } 273 inp=mtod(m, struct ip *); 274 memcpy((caddr_t)(inp + 1), &mob_h, (unsigned)msiz); 275 NTOHS(inp->ip_len); 276 inp->ip_len += msiz; 277 } else { /* AF_INET */ 278 IF_DROP(&ifp->if_snd); 279 m_freem(m); 280 return (EINVAL); 281 } 282 } else if (sc->g_proto == IPPROTO_GRE) { 283 switch (dst->sa_family) { 284 case AF_INET: 285 inp = mtod(m, struct ip *); 286 etype = ETHERTYPE_IP; 287 break; 288 #ifdef NETATALK 289 case AF_APPLETALK: 290 etype = ETHERTYPE_ATALK; 291 break; 292 #endif 293 #ifdef NS 294 case AF_NS: 295 etype = ETHERTYPE_NS; 296 break; 297 #endif 298 default: 299 IF_DROP(&ifp->if_snd); 300 m_freem(m); 301 return (EAFNOSUPPORT); 302 } 303 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 304 } else { 305 error = EINVAL; 306 IF_DROP(&ifp->if_snd); 307 m_freem(m); 308 return (error); 309 } 310 311 if (m == NULL) { 312 IF_DROP(&ifp->if_snd); 313 return (ENOBUFS); 314 } 315 316 gh = mtod(m, struct greip *); 317 if (sc->g_proto == IPPROTO_GRE) { 318 /* we don't have any GRE flags for now */ 319 320 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 321 gh->gi_ptype = htons(etype); 322 } 323 324 gh->gi_pr = sc->g_proto; 325 if (sc->g_proto != IPPROTO_MOBILE) { 326 gh->gi_src = sc->g_src; 327 gh->gi_dst = sc->g_dst; 328 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 329 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 330 ((struct ip*)gh)->ip_tos = inp->ip_tos; 331 gh->gi_len = m->m_pkthdr.len; 332 } 333 334 ifp->if_opackets++; 335 ifp->if_obytes += m->m_pkthdr.len; 336 /* send it off */ 337 error = ip_output(m, NULL, &sc->route, 0, NULL); 338 if (error) 339 ifp->if_oerrors++; 340 return (error); 341 } 342 343 int 344 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 345 { 346 struct proc *p = curproc->l_proc; /* XXX */ 347 struct ifaddr *ifa = (struct ifaddr *)data; 348 struct ifreq *ifr = (struct ifreq *)data; 349 struct in_ifaddr *ia = (struct in_ifaddr *)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 case SIOCSIFDSTADDR: 362 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 363 break; 364 /* 365 * set tunnel endpoints in case that we "only" 366 * have ip over ip encapsulation. This allows to 367 * set tunnel endpoints with ifconfig. 368 */ 369 if (ifa->ifa_addr->sa_family == AF_INET) { 370 sa = ifa->ifa_addr; 371 sc->g_src = (satosin(sa))->sin_addr; 372 sc->g_dst = ia->ia_dstaddr.sin_addr; 373 if ((sc->g_src.s_addr != INADDR_ANY) && 374 (sc->g_dst.s_addr != INADDR_ANY)) { 375 if (sc->route.ro_rt != 0) /* free old route */ 376 RTFREE(sc->route.ro_rt); 377 if (gre_compute_route(sc) == 0) 378 ifp->if_flags |= IFF_UP; 379 } 380 } 381 break; 382 case SIOCSIFFLAGS: 383 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 384 break; 385 if ((sc->g_dst.s_addr == INADDR_ANY) || 386 (sc->g_src.s_addr == INADDR_ANY)) 387 ifp->if_flags &= ~IFF_UP; 388 389 switch (ifr->ifr_flags & LINK_MASK) { 390 case IFF_LINK0: 391 sc->g_proto = IPPROTO_GRE; 392 ifp->if_flags |= IFF_LINK0; 393 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 394 break; 395 case IFF_LINK2: 396 sc->g_proto = IPPROTO_MOBILE; 397 ifp->if_flags |= IFF_LINK2; 398 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1); 399 break; 400 } 401 break; 402 case SIOCSIFMTU: 403 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 404 break; 405 if (ifr->ifr_mtu > GREMTU || ifr->ifr_mtu < 576) { 406 error = EINVAL; 407 break; 408 } 409 ifp->if_mtu = ifr->ifr_mtu; 410 break; 411 case SIOCGIFMTU: 412 ifr->ifr_mtu = sc->sc_if.if_mtu; 413 break; 414 case SIOCADDMULTI: 415 case SIOCDELMULTI: 416 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 417 break; 418 if (ifr == 0) { 419 error = EAFNOSUPPORT; 420 break; 421 } 422 switch (ifr->ifr_addr.sa_family) { 423 #ifdef INET 424 case AF_INET: 425 break; 426 #endif 427 default: 428 error = EAFNOSUPPORT; 429 break; 430 } 431 break; 432 case GRESPROTO: 433 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 434 break; 435 sc->g_proto = ifr->ifr_flags; 436 switch (sc->g_proto) { 437 case IPPROTO_GRE : 438 ifp->if_flags |= IFF_LINK0; 439 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 440 break; 441 case IPPROTO_MOBILE : 442 ifp->if_flags |= IFF_LINK2; 443 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 444 break; 445 default: 446 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1|IFF_LINK2); 447 } 448 break; 449 case GREGPROTO: 450 ifr->ifr_flags = sc->g_proto; 451 break; 452 case GRESADDRS: 453 case GRESADDRD: 454 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 455 break; 456 /* 457 * set tunnel endpoints, compute a less specific route 458 * to the remote end and mark if as up 459 */ 460 sa = &ifr->ifr_addr; 461 if (cmd == GRESADDRS ) 462 sc->g_src = (satosin(sa))->sin_addr; 463 if (cmd == GRESADDRD ) 464 sc->g_dst = (satosin(sa))->sin_addr; 465 if ((sc->g_src.s_addr != INADDR_ANY) && 466 (sc->g_dst.s_addr != INADDR_ANY)) { 467 if (sc->route.ro_rt != 0) /* free old route */ 468 RTFREE(sc->route.ro_rt); 469 if (gre_compute_route(sc) == 0) 470 ifp->if_flags |= IFF_UP; 471 } 472 break; 473 case GREGADDRS: 474 si.sin_addr.s_addr = sc->g_src.s_addr; 475 sa = sintosa(&si); 476 ifr->ifr_addr = *sa; 477 break; 478 case GREGADDRD: 479 si.sin_addr.s_addr = sc->g_dst.s_addr; 480 sa = sintosa(&si); 481 ifr->ifr_addr = *sa; 482 break; 483 default: 484 error = EINVAL; 485 } 486 487 splx(s); 488 return (error); 489 } 490 491 /* 492 * computes a route to our destination that is not the one 493 * which would be taken by ip_output(), as this one will loop back to 494 * us. If the interface is p2p as a--->b, then a routing entry exists 495 * If we now send a packet to b (e.g. ping b), this will come down here 496 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 497 * if_gre. 498 * Goal here is to compute a route to b that is less specific than 499 * a-->b. We know that this one exists as in normal operation we have 500 * at least a default route which matches. 501 */ 502 int 503 gre_compute_route(struct gre_softc *sc) 504 { 505 struct route *ro; 506 u_int32_t a, b, c; 507 508 ro = &sc->route; 509 510 memset(ro, 0, sizeof(struct route)); 511 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 512 ro->ro_dst.sa_family = AF_INET; 513 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 514 515 /* 516 * toggle last bit, so our interface is not found, but a less 517 * specific route. I'd rather like to specify a shorter mask, 518 * but this is not possible. Should work though. XXX 519 * there is a simpler way ... 520 */ 521 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 522 a = ntohl(sc->g_dst.s_addr); 523 b = a & 0x01; 524 c = a & 0xfffffffe; 525 b = b ^ 0x01; 526 a = b | c; 527 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 528 = htonl(a); 529 } 530 531 #ifdef DIAGNOSTIC 532 printf("%s: searching a route to %s", sc->sc_if.if_xname, 533 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 534 #endif 535 536 rtalloc(ro); 537 538 /* 539 * check if this returned a route at all and this route is no 540 * recursion to ourself 541 */ 542 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 543 #ifdef DIAGNOSTIC 544 if (ro->ro_rt == NULL) 545 printf(" - no route found!\n"); 546 else 547 printf(" - route loops back to ourself!\n"); 548 #endif 549 return EADDRNOTAVAIL; 550 } 551 552 /* 553 * now change it back - else ip_output will just drop 554 * the route and search one to this interface ... 555 */ 556 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 557 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 558 559 #ifdef DIAGNOSTIC 560 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 561 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 562 printf("\n"); 563 #endif 564 565 return 0; 566 } 567 568 /* 569 * do a checksum of a buffer - much like in_cksum, which operates on 570 * mbufs. 571 */ 572 u_short 573 gre_in_cksum(u_short *p, u_int len) 574 { 575 u_int sum = 0; 576 int nwords = len >> 1; 577 578 while (nwords-- != 0) 579 sum += *p++; 580 581 if (len & 1) { 582 union { 583 u_short w; 584 u_char c[2]; 585 } u; 586 u.c[0] = *(u_char *)p; 587 u.c[1] = 0; 588 sum += u.w; 589 } 590 591 /* end-around-carry */ 592 sum = (sum >> 16) + (sum & 0xffff); 593 sum += (sum >> 16); 594 return (~sum); 595 } 596
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