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sys/net/if_gre.c
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1 /* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ 2 /* $FreeBSD$ */ 3 4 /*- 5 * Copyright (c) 1998 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Heiko W.Rupp <hwr@pilhuhn.de> 10 * 11 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de> 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the NetBSD 24 * Foundation, Inc. and its contributors. 25 * 4. Neither the name of The NetBSD Foundation nor the names of its 26 * contributors may be used to endorse or promote products derived 27 * from this software without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 30 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 31 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 32 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 33 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 34 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 35 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 39 * POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 /* 43 * Encapsulate L3 protocols into IP 44 * See RFC 2784 (successor of RFC 1701 and 1702) for more details. 45 * If_gre is compatible with Cisco GRE tunnels, so you can 46 * have a NetBSD box as the other end of a tunnel interface of a Cisco 47 * router. See gre(4) for more details. 48 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 49 */ 50 51 #include "opt_atalk.h" 52 #include "opt_inet.h" 53 #include "opt_inet6.h" 54 55 #include <sys/param.h> 56 #include <sys/kernel.h> 57 #include <sys/malloc.h> 58 #include <sys/module.h> 59 #include <sys/mbuf.h> 60 #include <sys/protosw.h> 61 #include <sys/socket.h> 62 #include <sys/sockio.h> 63 #include <sys/sysctl.h> 64 #include <sys/systm.h> 65 66 #include <net/ethernet.h> 67 #include <net/if.h> 68 #include <net/if_clone.h> 69 #include <net/if_types.h> 70 #include <net/route.h> 71 72 #ifdef INET 73 #include <netinet/in.h> 74 #include <netinet/in_systm.h> 75 #include <netinet/in_var.h> 76 #include <netinet/ip.h> 77 #include <netinet/ip_gre.h> 78 #include <netinet/ip_var.h> 79 #include <netinet/ip_encap.h> 80 #else 81 #error "Huh? if_gre without inet?" 82 #endif 83 84 #include <net/bpf.h> 85 86 #include <net/net_osdep.h> 87 #include <net/if_gre.h> 88 89 /* 90 * It is not easy to calculate the right value for a GRE MTU. 91 * We leave this task to the admin and use the same default that 92 * other vendors use. 93 */ 94 #define GREMTU 1476 95 96 #define GRENAME "gre" 97 98 /* 99 * gre_mtx protects all global variables in if_gre.c. 100 * XXX: gre_softc data not protected yet. 101 */ 102 struct mtx gre_mtx; 103 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 104 105 struct gre_softc_head gre_softc_list; 106 107 static int gre_clone_create(struct if_clone *, int); 108 static void gre_clone_destroy(struct ifnet *); 109 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 110 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 111 struct rtentry *rt); 112 113 IFC_SIMPLE_DECLARE(gre, 0); 114 115 static int gre_compute_route(struct gre_softc *sc); 116 117 static void greattach(void); 118 119 #ifdef INET 120 extern struct domain inetdomain; 121 static const struct protosw in_gre_protosw = 122 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 123 gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 124 0, 125 0, 0, 0, 0, 126 &rip_usrreqs 127 }; 128 static const struct protosw in_mobile_protosw = 129 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 130 gre_mobile_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 131 0, 132 0, 0, 0, 0, 133 &rip_usrreqs 134 }; 135 #endif 136 137 SYSCTL_DECL(_net_link); 138 SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0, 139 "Generic Routing Encapsulation"); 140 #ifndef MAX_GRE_NEST 141 /* 142 * This macro controls the default upper limitation on nesting of gre tunnels. 143 * Since, setting a large value to this macro with a careless configuration 144 * may introduce system crash, we don't allow any nestings by default. 145 * If you need to configure nested gre tunnels, you can define this macro 146 * in your kernel configuration file. However, if you do so, please be 147 * careful to configure the tunnels so that it won't make a loop. 148 */ 149 #define MAX_GRE_NEST 1 150 #endif 151 static int max_gre_nesting = MAX_GRE_NEST; 152 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 153 &max_gre_nesting, 0, "Max nested tunnels"); 154 155 /* ARGSUSED */ 156 static void 157 greattach(void) 158 { 159 160 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF); 161 LIST_INIT(&gre_softc_list); 162 if_clone_attach(&gre_cloner); 163 } 164 165 static int 166 gre_clone_create(ifc, unit) 167 struct if_clone *ifc; 168 int unit; 169 { 170 struct gre_softc *sc; 171 172 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO); 173 174 if_initname(&sc->sc_if, ifc->ifc_name, unit); 175 sc->sc_if.if_softc = sc; 176 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 177 sc->sc_if.if_type = IFT_TUNNEL; 178 sc->sc_if.if_addrlen = 0; 179 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 180 sc->sc_if.if_mtu = GREMTU; 181 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 182 sc->sc_if.if_output = gre_output; 183 sc->sc_if.if_ioctl = gre_ioctl; 184 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 185 sc->g_proto = IPPROTO_GRE; 186 sc->sc_if.if_flags |= IFF_LINK0; 187 sc->encap = NULL; 188 sc->called = 0; 189 sc->wccp_ver = WCCP_V1; 190 if_attach(&sc->sc_if); 191 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 192 mtx_lock(&gre_mtx); 193 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 194 mtx_unlock(&gre_mtx); 195 return (0); 196 } 197 198 static void 199 gre_destroy(struct gre_softc *sc) 200 { 201 202 #ifdef INET 203 if (sc->encap != NULL) 204 encap_detach(sc->encap); 205 #endif 206 bpfdetach(&sc->sc_if); 207 if_detach(&sc->sc_if); 208 free(sc, M_GRE); 209 } 210 211 static void 212 gre_clone_destroy(ifp) 213 struct ifnet *ifp; 214 { 215 struct gre_softc *sc = ifp->if_softc; 216 217 mtx_lock(&gre_mtx); 218 LIST_REMOVE(sc, sc_list); 219 mtx_unlock(&gre_mtx); 220 gre_destroy(sc); 221 } 222 223 /* 224 * The output routine. Takes a packet and encapsulates it in the protocol 225 * given by sc->g_proto. See also RFC 1701 and RFC 2004 226 */ 227 static int 228 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 229 struct rtentry *rt) 230 { 231 int error = 0; 232 struct gre_softc *sc = ifp->if_softc; 233 struct greip *gh; 234 struct ip *ip; 235 u_short ip_id = 0; 236 uint8_t ip_tos = 0; 237 u_int16_t etype = 0; 238 struct mobile_h mob_h; 239 240 /* 241 * gre may cause infinite recursion calls when misconfigured. 242 * We'll prevent this by introducing upper limit. 243 */ 244 if (++(sc->called) > max_gre_nesting) { 245 printf("%s: gre_output: recursively called too many " 246 "times(%d)\n", if_name(&sc->sc_if), sc->called); 247 m_freem(m); 248 error = EIO; /* is there better errno? */ 249 goto end; 250 } 251 252 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 253 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 254 m_freem(m); 255 error = ENETDOWN; 256 goto end; 257 } 258 259 gh = NULL; 260 ip = NULL; 261 262 if (ifp->if_bpf) { 263 u_int32_t af = dst->sa_family; 264 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 265 } 266 267 m->m_flags &= ~(M_BCAST|M_MCAST); 268 269 if (sc->g_proto == IPPROTO_MOBILE) { 270 if (dst->sa_family == AF_INET) { 271 struct mbuf *m0; 272 int msiz; 273 274 ip = mtod(m, struct ip *); 275 276 /* 277 * RFC2004 specifies that fragmented diagrams shouldn't 278 * be encapsulated. 279 */ 280 if ((ip->ip_off & IP_MF) != 0) { 281 _IF_DROP(&ifp->if_snd); 282 m_freem(m); 283 error = EINVAL; /* is there better errno? */ 284 goto end; 285 } 286 memset(&mob_h, 0, MOB_H_SIZ_L); 287 mob_h.proto = (ip->ip_p) << 8; 288 mob_h.odst = ip->ip_dst.s_addr; 289 ip->ip_dst.s_addr = sc->g_dst.s_addr; 290 291 /* 292 * If the packet comes from our host, we only change 293 * the destination address in the IP header. 294 * Else we also need to save and change the source 295 */ 296 if (in_hosteq(ip->ip_src, sc->g_src)) { 297 msiz = MOB_H_SIZ_S; 298 } else { 299 mob_h.proto |= MOB_H_SBIT; 300 mob_h.osrc = ip->ip_src.s_addr; 301 ip->ip_src.s_addr = sc->g_src.s_addr; 302 msiz = MOB_H_SIZ_L; 303 } 304 mob_h.proto = htons(mob_h.proto); 305 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 306 307 if ((m->m_data - msiz) < m->m_pktdat) { 308 /* need new mbuf */ 309 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 310 if (m0 == NULL) { 311 _IF_DROP(&ifp->if_snd); 312 m_freem(m); 313 error = ENOBUFS; 314 goto end; 315 } 316 m0->m_next = m; 317 m->m_data += sizeof(struct ip); 318 m->m_len -= sizeof(struct ip); 319 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 320 m0->m_len = msiz + sizeof(struct ip); 321 m0->m_data += max_linkhdr; 322 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 323 sizeof(struct ip)); 324 m = m0; 325 } else { /* we have some space left in the old one */ 326 m->m_data -= msiz; 327 m->m_len += msiz; 328 m->m_pkthdr.len += msiz; 329 bcopy(ip, mtod(m, caddr_t), 330 sizeof(struct ip)); 331 } 332 ip = mtod(m, struct ip *); 333 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 334 ip->ip_len = ntohs(ip->ip_len) + msiz; 335 } else { /* AF_INET */ 336 _IF_DROP(&ifp->if_snd); 337 m_freem(m); 338 error = EINVAL; 339 goto end; 340 } 341 } else if (sc->g_proto == IPPROTO_GRE) { 342 switch (dst->sa_family) { 343 case AF_INET: 344 ip = mtod(m, struct ip *); 345 ip_tos = ip->ip_tos; 346 ip_id = ip->ip_id; 347 etype = ETHERTYPE_IP; 348 break; 349 #ifdef INET6 350 case AF_INET6: 351 ip_id = ip_newid(); 352 etype = ETHERTYPE_IPV6; 353 break; 354 #endif 355 #ifdef NETATALK 356 case AF_APPLETALK: 357 etype = ETHERTYPE_ATALK; 358 break; 359 #endif 360 default: 361 _IF_DROP(&ifp->if_snd); 362 m_freem(m); 363 error = EAFNOSUPPORT; 364 goto end; 365 } 366 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 367 } else { 368 _IF_DROP(&ifp->if_snd); 369 m_freem(m); 370 error = EINVAL; 371 goto end; 372 } 373 374 if (m == NULL) { /* mbuf allocation failed */ 375 _IF_DROP(&ifp->if_snd); 376 error = ENOBUFS; 377 goto end; 378 } 379 380 gh = mtod(m, struct greip *); 381 if (sc->g_proto == IPPROTO_GRE) { 382 /* we don't have any GRE flags for now */ 383 memset((void *)gh, 0, sizeof(struct greip)); 384 gh->gi_ptype = htons(etype); 385 } 386 387 gh->gi_pr = sc->g_proto; 388 if (sc->g_proto != IPPROTO_MOBILE) { 389 gh->gi_src = sc->g_src; 390 gh->gi_dst = sc->g_dst; 391 ((struct ip*)gh)->ip_v = IPPROTO_IPV4; 392 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 393 ((struct ip*)gh)->ip_ttl = GRE_TTL; 394 ((struct ip*)gh)->ip_tos = ip_tos; 395 ((struct ip*)gh)->ip_id = ip_id; 396 gh->gi_len = m->m_pkthdr.len; 397 } 398 399 ifp->if_opackets++; 400 ifp->if_obytes += m->m_pkthdr.len; 401 /* 402 * Send it off and with IP_FORWARD flag to prevent it from 403 * overwriting the ip_id again. ip_id is already set to the 404 * ip_id of the encapsulated packet. 405 */ 406 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 407 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 408 end: 409 sc->called = 0; 410 if (error) 411 ifp->if_oerrors++; 412 return (error); 413 } 414 415 static int 416 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 417 { 418 struct ifreq *ifr = (struct ifreq *)data; 419 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 420 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 421 struct gre_softc *sc = ifp->if_softc; 422 int s; 423 struct sockaddr_in si; 424 struct sockaddr *sa = NULL; 425 int error; 426 struct sockaddr_in sp, sm, dp, dm; 427 428 error = 0; 429 430 s = splnet(); 431 switch (cmd) { 432 case SIOCSIFADDR: 433 ifp->if_flags |= IFF_UP; 434 break; 435 case SIOCSIFDSTADDR: 436 break; 437 case SIOCSIFFLAGS: 438 if ((error = suser(curthread)) != 0) 439 break; 440 if ((ifr->ifr_flags & IFF_LINK0) != 0) 441 sc->g_proto = IPPROTO_GRE; 442 else 443 sc->g_proto = IPPROTO_MOBILE; 444 if ((ifr->ifr_flags & IFF_LINK2) != 0) 445 sc->wccp_ver = WCCP_V2; 446 else 447 sc->wccp_ver = WCCP_V1; 448 goto recompute; 449 case SIOCSIFMTU: 450 if ((error = suser(curthread)) != 0) 451 break; 452 if (ifr->ifr_mtu < 576) { 453 error = EINVAL; 454 break; 455 } 456 ifp->if_mtu = ifr->ifr_mtu; 457 break; 458 case SIOCGIFMTU: 459 ifr->ifr_mtu = sc->sc_if.if_mtu; 460 break; 461 case SIOCADDMULTI: 462 case SIOCDELMULTI: 463 if ((error = suser(curthread)) != 0) 464 break; 465 if (ifr == 0) { 466 error = EAFNOSUPPORT; 467 break; 468 } 469 switch (ifr->ifr_addr.sa_family) { 470 #ifdef INET 471 case AF_INET: 472 break; 473 #endif 474 #ifdef INET6 475 case AF_INET6: 476 break; 477 #endif 478 default: 479 error = EAFNOSUPPORT; 480 break; 481 } 482 break; 483 case GRESPROTO: 484 if ((error = suser(curthread)) != 0) 485 break; 486 sc->g_proto = ifr->ifr_flags; 487 switch (sc->g_proto) { 488 case IPPROTO_GRE: 489 ifp->if_flags |= IFF_LINK0; 490 break; 491 case IPPROTO_MOBILE: 492 ifp->if_flags &= ~IFF_LINK0; 493 break; 494 default: 495 error = EPROTONOSUPPORT; 496 break; 497 } 498 goto recompute; 499 case GREGPROTO: 500 ifr->ifr_flags = sc->g_proto; 501 break; 502 case GRESADDRS: 503 case GRESADDRD: 504 if ((error = suser(curthread)) != 0) 505 break; 506 /* 507 * set tunnel endpoints, compute a less specific route 508 * to the remote end and mark if as up 509 */ 510 sa = &ifr->ifr_addr; 511 if (cmd == GRESADDRS) 512 sc->g_src = (satosin(sa))->sin_addr; 513 if (cmd == GRESADDRD) 514 sc->g_dst = (satosin(sa))->sin_addr; 515 recompute: 516 #ifdef INET 517 if (sc->encap != NULL) { 518 encap_detach(sc->encap); 519 sc->encap = NULL; 520 } 521 #endif 522 if ((sc->g_src.s_addr != INADDR_ANY) && 523 (sc->g_dst.s_addr != INADDR_ANY)) { 524 bzero(&sp, sizeof(sp)); 525 bzero(&sm, sizeof(sm)); 526 bzero(&dp, sizeof(dp)); 527 bzero(&dm, sizeof(dm)); 528 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 529 sizeof(struct sockaddr_in); 530 sp.sin_family = sm.sin_family = dp.sin_family = 531 dm.sin_family = AF_INET; 532 sp.sin_addr = sc->g_src; 533 dp.sin_addr = sc->g_dst; 534 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 535 INADDR_BROADCAST; 536 #ifdef INET 537 sc->encap = encap_attach(AF_INET, sc->g_proto, 538 sintosa(&sp), sintosa(&sm), sintosa(&dp), 539 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 540 &in_gre_protosw : &in_mobile_protosw, sc); 541 if (sc->encap == NULL) 542 printf("%s: unable to attach encap\n", 543 if_name(&sc->sc_if)); 544 #endif 545 if (sc->route.ro_rt != 0) /* free old route */ 546 RTFREE(sc->route.ro_rt); 547 if (gre_compute_route(sc) == 0) 548 ifp->if_flags |= IFF_RUNNING; 549 else 550 ifp->if_flags &= ~IFF_RUNNING; 551 } 552 break; 553 case GREGADDRS: 554 memset(&si, 0, sizeof(si)); 555 si.sin_family = AF_INET; 556 si.sin_len = sizeof(struct sockaddr_in); 557 si.sin_addr.s_addr = sc->g_src.s_addr; 558 sa = sintosa(&si); 559 ifr->ifr_addr = *sa; 560 break; 561 case GREGADDRD: 562 memset(&si, 0, sizeof(si)); 563 si.sin_family = AF_INET; 564 si.sin_len = sizeof(struct sockaddr_in); 565 si.sin_addr.s_addr = sc->g_dst.s_addr; 566 sa = sintosa(&si); 567 ifr->ifr_addr = *sa; 568 break; 569 case SIOCSIFPHYADDR: 570 if ((error = suser(curthread)) != 0) 571 break; 572 if (aifr->ifra_addr.sin_family != AF_INET || 573 aifr->ifra_dstaddr.sin_family != AF_INET) { 574 error = EAFNOSUPPORT; 575 break; 576 } 577 if (aifr->ifra_addr.sin_len != sizeof(si) || 578 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 579 error = EINVAL; 580 break; 581 } 582 sc->g_src = aifr->ifra_addr.sin_addr; 583 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 584 goto recompute; 585 case SIOCSLIFPHYADDR: 586 if ((error = suser(curthread)) != 0) 587 break; 588 if (lifr->addr.ss_family != AF_INET || 589 lifr->dstaddr.ss_family != AF_INET) { 590 error = EAFNOSUPPORT; 591 break; 592 } 593 if (lifr->addr.ss_len != sizeof(si) || 594 lifr->dstaddr.ss_len != sizeof(si)) { 595 error = EINVAL; 596 break; 597 } 598 sc->g_src = (satosin(&lifr->addr))->sin_addr; 599 sc->g_dst = 600 (satosin(&lifr->dstaddr))->sin_addr; 601 goto recompute; 602 case SIOCDIFPHYADDR: 603 if ((error = suser(curthread)) != 0) 604 break; 605 sc->g_src.s_addr = INADDR_ANY; 606 sc->g_dst.s_addr = INADDR_ANY; 607 goto recompute; 608 case SIOCGLIFPHYADDR: 609 if (sc->g_src.s_addr == INADDR_ANY || 610 sc->g_dst.s_addr == INADDR_ANY) { 611 error = EADDRNOTAVAIL; 612 break; 613 } 614 memset(&si, 0, sizeof(si)); 615 si.sin_family = AF_INET; 616 si.sin_len = sizeof(struct sockaddr_in); 617 si.sin_addr.s_addr = sc->g_src.s_addr; 618 memcpy(&lifr->addr, &si, sizeof(si)); 619 si.sin_addr.s_addr = sc->g_dst.s_addr; 620 memcpy(&lifr->dstaddr, &si, sizeof(si)); 621 break; 622 case SIOCGIFPSRCADDR: 623 #ifdef INET6 624 case SIOCGIFPSRCADDR_IN6: 625 #endif 626 if (sc->g_src.s_addr == INADDR_ANY) { 627 error = EADDRNOTAVAIL; 628 break; 629 } 630 memset(&si, 0, sizeof(si)); 631 si.sin_family = AF_INET; 632 si.sin_len = sizeof(struct sockaddr_in); 633 si.sin_addr.s_addr = sc->g_src.s_addr; 634 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 635 break; 636 case SIOCGIFPDSTADDR: 637 #ifdef INET6 638 case SIOCGIFPDSTADDR_IN6: 639 #endif 640 if (sc->g_dst.s_addr == INADDR_ANY) { 641 error = EADDRNOTAVAIL; 642 break; 643 } 644 memset(&si, 0, sizeof(si)); 645 si.sin_family = AF_INET; 646 si.sin_len = sizeof(struct sockaddr_in); 647 si.sin_addr.s_addr = sc->g_dst.s_addr; 648 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 649 break; 650 default: 651 error = EINVAL; 652 break; 653 } 654 655 splx(s); 656 return (error); 657 } 658 659 /* 660 * computes a route to our destination that is not the one 661 * which would be taken by ip_output(), as this one will loop back to 662 * us. If the interface is p2p as a--->b, then a routing entry exists 663 * If we now send a packet to b (e.g. ping b), this will come down here 664 * gets src=a, dst=b tacked on and would from ip_output() sent back to 665 * if_gre. 666 * Goal here is to compute a route to b that is less specific than 667 * a-->b. We know that this one exists as in normal operation we have 668 * at least a default route which matches. 669 */ 670 static int 671 gre_compute_route(struct gre_softc *sc) 672 { 673 struct route *ro; 674 u_int32_t a, b, c; 675 676 ro = &sc->route; 677 678 memset(ro, 0, sizeof(struct route)); 679 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 680 ro->ro_dst.sa_family = AF_INET; 681 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 682 683 /* 684 * toggle last bit, so our interface is not found, but a less 685 * specific route. I'd rather like to specify a shorter mask, 686 * but this is not possible. Should work though. XXX 687 * there is a simpler way ... 688 */ 689 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 690 a = ntohl(sc->g_dst.s_addr); 691 b = a & 0x01; 692 c = a & 0xfffffffe; 693 b = b ^ 0x01; 694 a = b | c; 695 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 696 = htonl(a); 697 } 698 699 #ifdef DIAGNOSTIC 700 printf("%s: searching for a route to %s", if_name(&sc->sc_if), 701 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 702 #endif 703 704 rtalloc(ro); 705 706 /* 707 * check if this returned a route at all and this route is no 708 * recursion to ourself 709 */ 710 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 711 #ifdef DIAGNOSTIC 712 if (ro->ro_rt == NULL) 713 printf(" - no route found!\n"); 714 else 715 printf(" - route loops back to ourself!\n"); 716 #endif 717 return EADDRNOTAVAIL; 718 } 719 720 /* 721 * now change it back - else ip_output will just drop 722 * the route and search one to this interface ... 723 */ 724 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 725 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 726 727 #ifdef DIAGNOSTIC 728 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 729 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 730 printf("\n"); 731 #endif 732 733 return 0; 734 } 735 736 /* 737 * do a checksum of a buffer - much like in_cksum, which operates on 738 * mbufs. 739 */ 740 u_int16_t 741 gre_in_cksum(u_int16_t *p, u_int len) 742 { 743 u_int32_t sum = 0; 744 int nwords = len >> 1; 745 746 while (nwords-- != 0) 747 sum += *p++; 748 749 if (len & 1) { 750 union { 751 u_short w; 752 u_char c[2]; 753 } u; 754 u.c[0] = *(u_char *)p; 755 u.c[1] = 0; 756 sum += u.w; 757 } 758 759 /* end-around-carry */ 760 sum = (sum >> 16) + (sum & 0xffff); 761 sum += (sum >> 16); 762 return (~sum); 763 } 764 765 static int 766 gremodevent(module_t mod, int type, void *data) 767 { 768 struct gre_softc *sc; 769 770 switch (type) { 771 case MOD_LOAD: 772 greattach(); 773 break; 774 case MOD_UNLOAD: 775 if_clone_detach(&gre_cloner); 776 777 mtx_lock(&gre_mtx); 778 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) { 779 LIST_REMOVE(sc, sc_list); 780 mtx_unlock(&gre_mtx); 781 gre_destroy(sc); 782 mtx_lock(&gre_mtx); 783 } 784 mtx_unlock(&gre_mtx); 785 mtx_destroy(&gre_mtx); 786 break; 787 default: 788 return EOPNOTSUPP; 789 } 790 return 0; 791 } 792 793 static moduledata_t gre_mod = { 794 "if_gre", 795 gremodevent, 796 0 797 }; 798 799 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 800 MODULE_VERSION(if_gre, 1);
Cache object: b81021ec7a5e4e108223f3379dc6470b
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