if_gre.c revision 1.21
1 /* $NetBSD: if_gre.c,v 1.21 2001/05/10 01:30:55 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 "gre.h" 49 #if NGRE > 0 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 * XXX this is below the standard MTU of 105 * 1500 Bytes, allowing for headers, 106 * but we should possibly do path mtu discovery 107 * before changing if state to up to find the 108 * correct value 109 */ 110 #define GREMTU 1450 111 #define LINK_MASK (IFF_LINK0|IFF_LINK1|IFF_LINK2) 112 113 struct gre_softc_head gre_softc_list; 114 115 int gre_clone_create __P((struct if_clone *, int)); 116 void gre_clone_destroy __P((struct ifnet *)); 117 118 struct if_clone gre_cloner = 119 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 120 121 void gre_compute_route(struct gre_softc *sc); 122 123 void greattach __P((int)); 124 125 /* ARGSUSED */ 126 void 127 greattach(count) 128 int count; 129 { 130 131 LIST_INIT(&gre_softc_list); 132 if_clone_attach(&gre_cloner); 133 } 134 135 int 136 gre_clone_create(ifc, unit) 137 struct if_clone *ifc; 138 int unit; 139 { 140 struct gre_softc *sc; 141 142 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 143 memset(sc, 0, sizeof(struct gre_softc)); 144 145 sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); 146 sc->sc_if.if_softc = sc; 147 sc->sc_if.if_type = IFT_OTHER; 148 sc->sc_if.if_addrlen = 4; 149 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 150 sc->sc_if.if_dlt = DLT_NULL; 151 sc->sc_if.if_mtu = GREMTU; 152 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 153 sc->sc_if.if_output = gre_output; 154 sc->sc_if.if_ioctl = gre_ioctl; 155 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 156 sc->g_proto = IPPROTO_GRE; 157 if_attach(&sc->sc_if); 158 if_alloc_sadl(&sc->sc_if); 159 #if NBPFILTER > 0 160 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 161 #endif 162 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 163 return (0); 164 } 165 166 void 167 gre_clone_destroy(ifp) 168 struct ifnet *ifp; 169 { 170 struct gre_softc *sc = ifp->if_softc; 171 172 LIST_REMOVE(sc, sc_list); 173 #if NBPFILTER > 0 174 bpfdetach(ifp); 175 #endif 176 if_detach(ifp); 177 free(sc, M_DEVBUF); 178 } 179 180 /* 181 * The output routine. Takes a packet and encapsulates it in the protocol 182 * given by sc->g_proto. See also RFC 1701 and RFC 2004 183 */ 184 int 185 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 186 struct rtentry *rt) 187 { 188 int error = 0; 189 struct gre_softc *sc = ifp->if_softc; 190 struct greip *gh; 191 struct ip *inp; 192 u_char ttl, osrc; 193 u_short etype = 0; 194 struct mobile_h mob_h; 195 196 gh = NULL; 197 inp = NULL; 198 osrc = 0; 199 200 #if NBPFILTER >0 201 if (ifp->if_bpf) { 202 /* see comment of other if_foo.c files */ 203 struct mbuf m0; 204 u_int32_t af = dst->sa_family; 205 206 m0.m_next = m; 207 m0.m_len = 4; 208 m0.m_data = (char *)⁡ 209 210 bpf_mtap(ifp->if_bpf, &m0); 211 } 212 #endif 213 214 ttl = 255; 215 216 if (sc->g_proto == IPPROTO_MOBILE) { 217 if (dst->sa_family == AF_INET) { 218 struct mbuf *m0; 219 int msiz; 220 221 inp = mtod(m, struct ip *); 222 223 memset(&mob_h, 0, MOB_H_SIZ_L); 224 mob_h.proto = (inp->ip_p) << 8; 225 mob_h.odst = inp->ip_dst.s_addr; 226 inp->ip_dst.s_addr = sc->g_dst.s_addr; 227 228 /* 229 * If the packet comes from our host, we only change 230 * the destination address in the IP header. 231 * Else we also need to save and change the source 232 */ 233 if (in_hosteq(inp->ip_src, sc->g_src)) { 234 msiz = MOB_H_SIZ_S; 235 } else { 236 mob_h.proto |= MOB_H_SBIT; 237 mob_h.osrc = inp->ip_src.s_addr; 238 inp->ip_src.s_addr = sc->g_src.s_addr; 239 msiz = MOB_H_SIZ_L; 240 } 241 HTONS(mob_h.proto); 242 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 243 244 if ((m->m_data - msiz) < m->m_pktdat) { 245 /* need new mbuf */ 246 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 247 if (m0 == NULL) { 248 IF_DROP(&ifp->if_snd); 249 m_freem(m); 250 return (ENOBUFS); 251 } 252 m0->m_next = m; 253 m->m_data += sizeof(struct ip); 254 m->m_len -= sizeof(struct ip); 255 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 256 m0->m_len = msiz + sizeof(struct ip); 257 m0->m_data += max_linkhdr; 258 memcpy(mtod(m0, caddr_t), (caddr_t)inp, 259 sizeof(struct ip)); 260 m = m0; 261 } else { /* we have some space left in the old one */ 262 m->m_data -= msiz; 263 m->m_len += msiz; 264 m->m_pkthdr.len += msiz; 265 memmove(mtod(m, caddr_t), inp, 266 sizeof(struct ip)); 267 } 268 inp=mtod(m, struct ip *); 269 memcpy((caddr_t)(inp + 1), &mob_h, (unsigned)msiz); 270 NTOHS(inp->ip_len); 271 inp->ip_len += msiz; 272 } else { /* AF_INET */ 273 IF_DROP(&ifp->if_snd); 274 m_freem(m); 275 return (EINVAL); 276 } 277 } else if (sc->g_proto == IPPROTO_GRE) { 278 switch (dst->sa_family) { 279 case AF_INET: 280 inp = mtod(m, struct ip *); 281 ttl = inp->ip_ttl; 282 etype = ETHERTYPE_IP; 283 break; 284 #ifdef NETATALK 285 case AF_APPLETALK: 286 etype = ETHERTYPE_ATALK; 287 break; 288 #endif 289 #ifdef NS 290 case AF_NS: 291 etype = ETHERTYPE_NS; 292 break; 293 #endif 294 default: 295 IF_DROP(&ifp->if_snd); 296 m_freem(m); 297 return (EAFNOSUPPORT); 298 } 299 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 300 } else { 301 error = EINVAL; 302 IF_DROP(&ifp->if_snd); 303 m_freem(m); 304 return (error); 305 } 306 307 if (m == NULL) { 308 IF_DROP(&ifp->if_snd); 309 return (ENOBUFS); 310 } 311 312 gh = mtod(m, struct greip *); 313 if (sc->g_proto == IPPROTO_GRE) { 314 /* we don't have any GRE flags for now */ 315 316 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 317 gh->gi_ptype = htons(etype); 318 } 319 320 gh->gi_pr = sc->g_proto; 321 if (sc->g_proto != IPPROTO_MOBILE) { 322 gh->gi_src = sc->g_src; 323 gh->gi_dst = sc->g_dst; 324 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 325 ((struct ip*)gh)->ip_ttl = ttl; 326 ((struct ip*)gh)->ip_tos = inp->ip_tos; 327 gh->gi_len = m->m_pkthdr.len; 328 } 329 330 ifp->if_opackets++; 331 ifp->if_obytes += m->m_pkthdr.len; 332 /* send it off */ 333 error = ip_output(m, NULL, &sc->route, 0, NULL); 334 if (error) 335 ifp->if_oerrors++; 336 return (error); 337 } 338 339 int 340 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 341 { 342 struct proc *p = curproc; /* XXX */ 343 struct ifaddr *ifa = (struct ifaddr *)data; 344 struct ifreq *ifr = (struct ifreq *)data; 345 struct in_ifaddr *ia = (struct in_ifaddr *)data; 346 struct gre_softc *sc = ifp->if_softc; 347 int s; 348 struct sockaddr_in si; 349 struct sockaddr *sa = NULL; 350 int error; 351 352 error = 0; 353 354 s = splnet(); 355 switch (cmd) { 356 case SIOCSIFADDR: 357 case SIOCSIFDSTADDR: 358 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 359 break; 360 /* 361 * set tunnel endpoints in case that we "only" 362 * have ip over ip encapsulation. This allows to 363 * set tunnel endpoints with ifconfig. 364 */ 365 if (ifa->ifa_addr->sa_family == AF_INET) { 366 sa = ifa->ifa_addr; 367 sc->g_src = (satosin(sa))->sin_addr; 368 sc->g_dst = ia->ia_dstaddr.sin_addr; 369 if ((sc->g_src.s_addr != INADDR_ANY) && 370 (sc->g_dst.s_addr != INADDR_ANY)) { 371 if (sc->route.ro_rt != 0) /* free old route */ 372 RTFREE(sc->route.ro_rt); 373 gre_compute_route(sc); 374 ifp->if_flags |= IFF_UP; 375 } 376 } 377 break; 378 case SIOCSIFFLAGS: 379 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 380 break; 381 if ((sc->g_dst.s_addr == INADDR_ANY) || 382 (sc->g_src.s_addr == INADDR_ANY)) 383 ifp->if_flags &= ~IFF_UP; 384 385 switch (ifr->ifr_flags & LINK_MASK) { 386 case IFF_LINK0: 387 sc->g_proto = IPPROTO_GRE; 388 ifp->if_flags |= IFF_LINK0; 389 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 390 break; 391 case IFF_LINK2: 392 sc->g_proto = IPPROTO_MOBILE; 393 ifp->if_flags |= IFF_LINK2; 394 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1); 395 break; 396 } 397 break; 398 case SIOCSIFMTU: 399 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 400 break; 401 if (ifr->ifr_mtu > GREMTU || ifr->ifr_mtu < 576) { 402 error = EINVAL; 403 break; 404 } 405 ifp->if_mtu = ifr->ifr_mtu; 406 break; 407 case SIOCGIFMTU: 408 ifr->ifr_mtu = sc->sc_if.if_mtu; 409 break; 410 case SIOCADDMULTI: 411 case SIOCDELMULTI: 412 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 413 break; 414 if (ifr == 0) { 415 error = EAFNOSUPPORT; 416 break; 417 } 418 switch (ifr->ifr_addr.sa_family) { 419 #ifdef INET 420 case AF_INET: 421 break; 422 #endif 423 default: 424 error = EAFNOSUPPORT; 425 break; 426 } 427 break; 428 case GRESPROTO: 429 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 430 break; 431 sc->g_proto = ifr->ifr_flags; 432 switch (sc->g_proto) { 433 case IPPROTO_GRE : 434 ifp->if_flags |= IFF_LINK0; 435 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 436 break; 437 case IPPROTO_MOBILE : 438 ifp->if_flags |= IFF_LINK2; 439 ifp->if_flags &= ~(IFF_LINK1|IFF_LINK2); 440 break; 441 default: 442 ifp->if_flags &= ~(IFF_LINK0|IFF_LINK1|IFF_LINK2); 443 } 444 break; 445 case GREGPROTO: 446 ifr->ifr_flags = sc->g_proto; 447 break; 448 case GRESADDRS: 449 case GRESADDRD: 450 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 451 break; 452 /* 453 * set tunnel endpoints, compute a less specific route 454 * to the remote end and mark if as up 455 */ 456 sa = &ifr->ifr_addr; 457 if (cmd == GRESADDRS ) 458 sc->g_src = (satosin(sa))->sin_addr; 459 if (cmd == GRESADDRD ) 460 sc->g_dst = (satosin(sa))->sin_addr; 461 if ((sc->g_src.s_addr != INADDR_ANY) && 462 (sc->g_dst.s_addr != INADDR_ANY)) { 463 if (sc->route.ro_rt != 0) /* free old route */ 464 RTFREE(sc->route.ro_rt); 465 gre_compute_route(sc); 466 ifp->if_flags |= IFF_UP; 467 } 468 break; 469 case GREGADDRS: 470 si.sin_addr.s_addr = sc->g_src.s_addr; 471 sa = sintosa(&si); 472 ifr->ifr_addr = *sa; 473 break; 474 case GREGADDRD: 475 si.sin_addr.s_addr = sc->g_dst.s_addr; 476 sa = sintosa(&si); 477 ifr->ifr_addr = *sa; 478 break; 479 default: 480 error = EINVAL; 481 } 482 483 splx(s); 484 return (error); 485 } 486 487 /* 488 * computes a route to our destination that is not the one 489 * which would be taken by ip_output(), as this one will loop back to 490 * us. If the interface is p2p as a--->b, then a routing entry exists 491 * If we now send a packet to b (e.g. ping b), this will come down here 492 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 493 * if_gre. 494 * Goal here is to compute a route to b that is less specific than 495 * a-->b. We know that this one exists as in normal operation we have 496 * at least a default route which matches. 497 */ 498 void 499 gre_compute_route(struct gre_softc *sc) 500 { 501 struct route *ro; 502 u_int32_t a, b, c; 503 504 ro = &sc->route; 505 506 memset(ro, 0, sizeof(struct route)); 507 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 508 ro->ro_dst.sa_family = AF_INET; 509 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 510 511 /* 512 * toggle last bit, so our interface is not found, but a less 513 * specific route. I'd rather like to specify a shorter mask, 514 * but this is not possible. Should work though. XXX 515 * there is a simpler way ... 516 */ 517 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 518 a = ntohl(sc->g_dst.s_addr); 519 b = a & 0x01; 520 c = a & 0xfffffffe; 521 b = b ^ 0x01; 522 a = b | c; 523 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 524 = htonl(a); 525 } 526 527 #ifdef DIAGNOSTIC 528 printf("%s: searching a route to %s", sc->sc_if.if_xname, 529 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 530 #endif 531 532 rtalloc(ro); 533 534 /* 535 * now change it back - else ip_output will just drop 536 * the route and search one to this interface ... 537 */ 538 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 539 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 540 541 #ifdef DIAGNOSTIC 542 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 543 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 544 printf("\n"); 545 #endif 546 } 547 548 /* 549 * do a checksum of a buffer - much like in_cksum, which operates on 550 * mbufs. 551 */ 552 u_short 553 gre_in_cksum(u_short *p, u_int len) 554 { 555 u_int sum = 0; 556 int nwords = len >> 1; 557 558 while (nwords-- != 0) 559 sum += *p++; 560 561 if (len & 1) { 562 union { 563 u_short w; 564 u_char c[2]; 565 } u; 566 u.c[0] = *(u_char *)p; 567 u.c[1] = 0; 568 sum += u.w; 569 } 570 571 /* end-around-carry */ 572 sum = (sum >> 16) + (sum & 0xffff); 573 sum += (sum >> 16); 574 return (~sum); 575 } 576 #endif 577
Indexes created Fri Sep 26 20:09:58 GMT 2025