if_gre.c revision 147256
1/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ 2/* $FreeBSD: head/sys/net/if_gre.c 147256 2005-06-10 16:49:24Z brooks $ */ 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 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40/* 41 * Encapsulate L3 protocols into IP 42 * See RFC 1701 and 1702 for more details. 43 * If_gre is compatible with Cisco GRE tunnels, so you can 44 * have a NetBSD box as the other end of a tunnel interface of a Cisco 45 * router. See gre(4) for more details. 46 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 47 */ 48 49#include "opt_atalk.h" 50#include "opt_inet.h" 51#include "opt_inet6.h" 52 53#include <sys/param.h> 54#include <sys/kernel.h> 55#include <sys/malloc.h> 56#include <sys/module.h> 57#include <sys/mbuf.h> 58#include <sys/protosw.h> 59#include <sys/socket.h> 60#include <sys/sockio.h> 61#include <sys/sysctl.h> 62#include <sys/systm.h> 63 64#include <net/ethernet.h> 65#include <net/if.h> 66#include <net/if_clone.h> 67#include <net/if_types.h> 68#include <net/route.h> 69 70#ifdef INET 71#include <netinet/in.h> 72#include <netinet/in_systm.h> 73#include <netinet/in_var.h> 74#include <netinet/ip.h> 75#include <netinet/ip_gre.h> 76#include <netinet/ip_var.h> 77#include <netinet/ip_encap.h> 78#else 79#error "Huh? if_gre without inet?" 80#endif 81 82#include <net/bpf.h> 83 84#include <net/net_osdep.h> 85#include <net/if_gre.h> 86 87/* 88 * It is not easy to calculate the right value for a GRE MTU. 89 * We leave this task to the admin and use the same default that 90 * other vendors use. 91 */ 92#define GREMTU 1476 93 94#define GRENAME "gre" 95 96/* 97 * gre_mtx protects all global variables in if_gre.c. 98 * XXX: gre_softc data not protected yet. 99 */ 100struct mtx gre_mtx; 101static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 102 103struct gre_softc_head gre_softc_list; 104 105static int gre_clone_create(struct if_clone *, int); 106static void gre_clone_destroy(struct ifnet *); 107static int gre_ioctl(struct ifnet *, u_long, caddr_t); 108static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 109 struct rtentry *rt); 110 111IFC_SIMPLE_DECLARE(gre, 0); 112 113static int gre_compute_route(struct gre_softc *sc); 114 115static void greattach(void); 116 117#ifdef INET 118extern struct domain inetdomain; 119static const struct protosw in_gre_protosw = 120{ SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 121 (pr_input_t*)gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 122 0, 123 0, 0, 0, 0, 124 &rip_usrreqs 125}; 126static const struct protosw in_mobile_protosw = 127{ SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 128 (pr_input_t*)gre_mobile_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 129 0, 130 0, 0, 0, 0, 131 &rip_usrreqs 132}; 133#endif 134 135SYSCTL_DECL(_net_link); 136SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0, 137 "Generic Routing Encapsulation"); 138#ifndef MAX_GRE_NEST 139/* 140 * This macro controls the default upper limitation on nesting of gre tunnels. 141 * Since, setting a large value to this macro with a careless configuration 142 * may introduce system crash, we don't allow any nestings by default. 143 * If you need to configure nested gre tunnels, you can define this macro 144 * in your kernel configuration file. However, if you do so, please be 145 * careful to configure the tunnels so that it won't make a loop. 146 */ 147#define MAX_GRE_NEST 1 148#endif 149static int max_gre_nesting = MAX_GRE_NEST; 150SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 151 &max_gre_nesting, 0, "Max nested tunnels"); 152 153/* ARGSUSED */ 154static void 155greattach(void) 156{ 157 158 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF); 159 LIST_INIT(&gre_softc_list); 160 if_clone_attach(&gre_cloner); 161} 162 163static int 164gre_clone_create(ifc, unit) 165 struct if_clone *ifc; 166 int unit; 167{ 168 struct gre_softc *sc; 169 170 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO); 171 172 if_initname(GRE2IFP(sc), ifc->ifc_name, unit); 173 GRE2IFP(sc)->if_softc = sc; 174 GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN; 175 GRE2IFP(sc)->if_type = IFT_TUNNEL; 176 GRE2IFP(sc)->if_addrlen = 0; 177 GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */ 178 GRE2IFP(sc)->if_mtu = GREMTU; 179 GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 180 GRE2IFP(sc)->if_output = gre_output; 181 GRE2IFP(sc)->if_ioctl = gre_ioctl; 182 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 183 sc->g_proto = IPPROTO_GRE; 184 GRE2IFP(sc)->if_flags |= IFF_LINK0; 185 sc->encap = NULL; 186 sc->called = 0; 187 sc->wccp_ver = WCCP_V1; 188 if_attach(GRE2IFP(sc)); 189 bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t)); 190 mtx_lock(&gre_mtx); 191 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 192 mtx_unlock(&gre_mtx); 193 return (0); 194} 195 196static void 197gre_destroy(struct gre_softc *sc) 198{ 199 200#ifdef INET 201 if (sc->encap != NULL) 202 encap_detach(sc->encap); 203#endif 204 bpfdetach(GRE2IFP(sc)); 205 if_detach(GRE2IFP(sc)); 206 if_free(GRE2IFP(sc)); 207 free(sc, M_GRE); 208} 209 210static void 211gre_clone_destroy(ifp) 212 struct ifnet *ifp; 213{ 214 struct gre_softc *sc = ifp->if_softc; 215 216 mtx_lock(&gre_mtx); 217 LIST_REMOVE(sc, sc_list); 218 mtx_unlock(&gre_mtx); 219 gre_destroy(sc); 220} 221 222/* 223 * The output routine. Takes a packet and encapsulates it in the protocol 224 * given by sc->g_proto. See also RFC 1701 and RFC 2004 225 */ 226static int 227gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 228 struct rtentry *rt) 229{ 230 int error = 0; 231 struct gre_softc *sc = ifp->if_softc; 232 struct greip *gh; 233 struct ip *ip; 234 u_int16_t etype = 0; 235 struct mobile_h mob_h; 236 237 /* 238 * gre may cause infinite recursion calls when misconfigured. 239 * We'll prevent this by introducing upper limit. 240 */ 241 if (++(sc->called) > max_gre_nesting) { 242 printf("%s: gre_output: recursively called too many " 243 "times(%d)\n", if_name(GRE2IFP(sc)), sc->called); 244 m_freem(m); 245 error = EIO; /* is there better errno? */ 246 goto end; 247 } 248 249 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 250 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 251 m_freem(m); 252 error = ENETDOWN; 253 goto end; 254 } 255 256 gh = NULL; 257 ip = NULL; 258 259 if (ifp->if_bpf) { 260 u_int32_t af = dst->sa_family; 261 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 262 } 263 264 m->m_flags &= ~(M_BCAST|M_MCAST); 265 266 if (sc->g_proto == IPPROTO_MOBILE) { 267 if (dst->sa_family == AF_INET) { 268 struct mbuf *m0; 269 int msiz; 270 271 ip = mtod(m, struct ip *); 272 273 /* 274 * RFC2004 specifies that fragmented diagrams shouldn't 275 * be encapsulated. 276 */ 277 if ((ip->ip_off & IP_MF) != 0) { 278 _IF_DROP(&ifp->if_snd); 279 m_freem(m); 280 error = EINVAL; /* is there better errno? */ 281 goto end; 282 } 283 memset(&mob_h, 0, MOB_H_SIZ_L); 284 mob_h.proto = (ip->ip_p) << 8; 285 mob_h.odst = ip->ip_dst.s_addr; 286 ip->ip_dst.s_addr = sc->g_dst.s_addr; 287 288 /* 289 * If the packet comes from our host, we only change 290 * the destination address in the IP header. 291 * Else we also need to save and change the source 292 */ 293 if (in_hosteq(ip->ip_src, sc->g_src)) { 294 msiz = MOB_H_SIZ_S; 295 } else { 296 mob_h.proto |= MOB_H_SBIT; 297 mob_h.osrc = ip->ip_src.s_addr; 298 ip->ip_src.s_addr = sc->g_src.s_addr; 299 msiz = MOB_H_SIZ_L; 300 } 301 mob_h.proto = htons(mob_h.proto); 302 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 303 304 if ((m->m_data - msiz) < m->m_pktdat) { 305 /* need new mbuf */ 306 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 307 if (m0 == NULL) { 308 _IF_DROP(&ifp->if_snd); 309 m_freem(m); 310 error = ENOBUFS; 311 goto end; 312 } 313 m0->m_next = m; 314 m->m_data += sizeof(struct ip); 315 m->m_len -= sizeof(struct ip); 316 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 317 m0->m_len = msiz + sizeof(struct ip); 318 m0->m_data += max_linkhdr; 319 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 320 sizeof(struct ip)); 321 m = m0; 322 } else { /* we have some space left in the old one */ 323 m->m_data -= msiz; 324 m->m_len += msiz; 325 m->m_pkthdr.len += msiz; 326 bcopy(ip, mtod(m, caddr_t), 327 sizeof(struct ip)); 328 } 329 ip = mtod(m, struct ip *); 330 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 331 ip->ip_len = ntohs(ip->ip_len) + msiz; 332 } else { /* AF_INET */ 333 _IF_DROP(&ifp->if_snd); 334 m_freem(m); 335 error = EINVAL; 336 goto end; 337 } 338 } else if (sc->g_proto == IPPROTO_GRE) { 339 switch (dst->sa_family) { 340 case AF_INET: 341 ip = mtod(m, struct ip *); 342 etype = ETHERTYPE_IP; 343 break; 344#ifdef NETATALK 345 case AF_APPLETALK: 346 etype = ETHERTYPE_ATALK; 347 break; 348#endif 349 default: 350 _IF_DROP(&ifp->if_snd); 351 m_freem(m); 352 error = EAFNOSUPPORT; 353 goto end; 354 } 355 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 356 } else { 357 _IF_DROP(&ifp->if_snd); 358 m_freem(m); 359 error = EINVAL; 360 goto end; 361 } 362 363 if (m == NULL) { /* mbuf allocation failed */ 364 _IF_DROP(&ifp->if_snd); 365 error = ENOBUFS; 366 goto end; 367 } 368 369 gh = mtod(m, struct greip *); 370 if (sc->g_proto == IPPROTO_GRE) { 371 /* we don't have any GRE flags for now */ 372 memset((void *)gh, 0, sizeof(struct greip)); 373 gh->gi_ptype = htons(etype); 374 } 375 376 gh->gi_pr = sc->g_proto; 377 if (sc->g_proto != IPPROTO_MOBILE) { 378 gh->gi_src = sc->g_src; 379 gh->gi_dst = sc->g_dst; 380 ((struct ip*)gh)->ip_v = IPPROTO_IPV4; 381 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 382 ((struct ip*)gh)->ip_ttl = GRE_TTL; 383 ((struct ip*)gh)->ip_tos = ip->ip_tos; 384 ((struct ip*)gh)->ip_id = ip->ip_id; 385 gh->gi_len = m->m_pkthdr.len; 386 } 387 388 ifp->if_opackets++; 389 ifp->if_obytes += m->m_pkthdr.len; 390 /* 391 * Send it off and with IP_FORWARD flag to prevent it from 392 * overwriting the ip_id again. ip_id is already set to the 393 * ip_id of the encapsulated packet. 394 */ 395 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 396 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 397 end: 398 sc->called = 0; 399 if (error) 400 ifp->if_oerrors++; 401 return (error); 402} 403 404static int 405gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 406{ 407 struct ifreq *ifr = (struct ifreq *)data; 408 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 409 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 410 struct gre_softc *sc = ifp->if_softc; 411 int s; 412 struct sockaddr_in si; 413 struct sockaddr *sa = NULL; 414 int error; 415 struct sockaddr_in sp, sm, dp, dm; 416 417 error = 0; 418 419 s = splnet(); 420 switch (cmd) { 421 case SIOCSIFADDR: 422 ifp->if_flags |= IFF_UP; 423 break; 424 case SIOCSIFDSTADDR: 425 break; 426 case SIOCSIFFLAGS: 427 if ((error = suser(curthread)) != 0) 428 break; 429 if ((ifr->ifr_flags & IFF_LINK0) != 0) 430 sc->g_proto = IPPROTO_GRE; 431 else 432 sc->g_proto = IPPROTO_MOBILE; 433 if ((ifr->ifr_flags & IFF_LINK2) != 0) 434 sc->wccp_ver = WCCP_V2; 435 else 436 sc->wccp_ver = WCCP_V1; 437 goto recompute; 438 case SIOCSIFMTU: 439 if ((error = suser(curthread)) != 0) 440 break; 441 if (ifr->ifr_mtu < 576) { 442 error = EINVAL; 443 break; 444 } 445 ifp->if_mtu = ifr->ifr_mtu; 446 break; 447 case SIOCGIFMTU: 448 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu; 449 break; 450 case SIOCADDMULTI: 451 case SIOCDELMULTI: 452 if ((error = suser(curthread)) != 0) 453 break; 454 if (ifr == 0) { 455 error = EAFNOSUPPORT; 456 break; 457 } 458 switch (ifr->ifr_addr.sa_family) { 459#ifdef INET 460 case AF_INET: 461 break; 462#endif 463 default: 464 error = EAFNOSUPPORT; 465 break; 466 } 467 break; 468 case GRESPROTO: 469 if ((error = suser(curthread)) != 0) 470 break; 471 sc->g_proto = ifr->ifr_flags; 472 switch (sc->g_proto) { 473 case IPPROTO_GRE: 474 ifp->if_flags |= IFF_LINK0; 475 break; 476 case IPPROTO_MOBILE: 477 ifp->if_flags &= ~IFF_LINK0; 478 break; 479 default: 480 error = EPROTONOSUPPORT; 481 break; 482 } 483 goto recompute; 484 case GREGPROTO: 485 ifr->ifr_flags = sc->g_proto; 486 break; 487 case GRESADDRS: 488 case GRESADDRD: 489 if ((error = suser(curthread)) != 0) 490 break; 491 /* 492 * set tunnel endpoints, compute a less specific route 493 * to the remote end and mark if as up 494 */ 495 sa = &ifr->ifr_addr; 496 if (cmd == GRESADDRS) 497 sc->g_src = (satosin(sa))->sin_addr; 498 if (cmd == GRESADDRD) 499 sc->g_dst = (satosin(sa))->sin_addr; 500 recompute: 501#ifdef INET 502 if (sc->encap != NULL) { 503 encap_detach(sc->encap); 504 sc->encap = NULL; 505 } 506#endif 507 if ((sc->g_src.s_addr != INADDR_ANY) && 508 (sc->g_dst.s_addr != INADDR_ANY)) { 509 bzero(&sp, sizeof(sp)); 510 bzero(&sm, sizeof(sm)); 511 bzero(&dp, sizeof(dp)); 512 bzero(&dm, sizeof(dm)); 513 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 514 sizeof(struct sockaddr_in); 515 sp.sin_family = sm.sin_family = dp.sin_family = 516 dm.sin_family = AF_INET; 517 sp.sin_addr = sc->g_src; 518 dp.sin_addr = sc->g_dst; 519 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 520 INADDR_BROADCAST; 521#ifdef INET 522 sc->encap = encap_attach(AF_INET, sc->g_proto, 523 sintosa(&sp), sintosa(&sm), sintosa(&dp), 524 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 525 &in_gre_protosw : &in_mobile_protosw, sc); 526 if (sc->encap == NULL) 527 printf("%s: unable to attach encap\n", 528 if_name(GRE2IFP(sc))); 529#endif 530 if (sc->route.ro_rt != 0) /* free old route */ 531 RTFREE(sc->route.ro_rt); 532 if (gre_compute_route(sc) == 0) 533 ifp->if_flags |= IFF_RUNNING; 534 else 535 ifp->if_flags &= ~IFF_RUNNING; 536 } 537 break; 538 case GREGADDRS: 539 memset(&si, 0, sizeof(si)); 540 si.sin_family = AF_INET; 541 si.sin_len = sizeof(struct sockaddr_in); 542 si.sin_addr.s_addr = sc->g_src.s_addr; 543 sa = sintosa(&si); 544 ifr->ifr_addr = *sa; 545 break; 546 case GREGADDRD: 547 memset(&si, 0, sizeof(si)); 548 si.sin_family = AF_INET; 549 si.sin_len = sizeof(struct sockaddr_in); 550 si.sin_addr.s_addr = sc->g_dst.s_addr; 551 sa = sintosa(&si); 552 ifr->ifr_addr = *sa; 553 break; 554 case SIOCSIFPHYADDR: 555 if ((error = suser(curthread)) != 0) 556 break; 557 if (aifr->ifra_addr.sin_family != AF_INET || 558 aifr->ifra_dstaddr.sin_family != AF_INET) { 559 error = EAFNOSUPPORT; 560 break; 561 } 562 if (aifr->ifra_addr.sin_len != sizeof(si) || 563 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 564 error = EINVAL; 565 break; 566 } 567 sc->g_src = aifr->ifra_addr.sin_addr; 568 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 569 goto recompute; 570 case SIOCSLIFPHYADDR: 571 if ((error = suser(curthread)) != 0) 572 break; 573 if (lifr->addr.ss_family != AF_INET || 574 lifr->dstaddr.ss_family != AF_INET) { 575 error = EAFNOSUPPORT; 576 break; 577 } 578 if (lifr->addr.ss_len != sizeof(si) || 579 lifr->dstaddr.ss_len != sizeof(si)) { 580 error = EINVAL; 581 break; 582 } 583 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 584 sc->g_dst = 585 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 586 goto recompute; 587 case SIOCDIFPHYADDR: 588 if ((error = suser(curthread)) != 0) 589 break; 590 sc->g_src.s_addr = INADDR_ANY; 591 sc->g_dst.s_addr = INADDR_ANY; 592 goto recompute; 593 case SIOCGLIFPHYADDR: 594 if (sc->g_src.s_addr == INADDR_ANY || 595 sc->g_dst.s_addr == INADDR_ANY) { 596 error = EADDRNOTAVAIL; 597 break; 598 } 599 memset(&si, 0, sizeof(si)); 600 si.sin_family = AF_INET; 601 si.sin_len = sizeof(struct sockaddr_in); 602 si.sin_addr.s_addr = sc->g_src.s_addr; 603 memcpy(&lifr->addr, &si, sizeof(si)); 604 si.sin_addr.s_addr = sc->g_dst.s_addr; 605 memcpy(&lifr->dstaddr, &si, sizeof(si)); 606 break; 607 case SIOCGIFPSRCADDR: 608#ifdef INET6 609 case SIOCGIFPSRCADDR_IN6: 610#endif 611 if (sc->g_src.s_addr == INADDR_ANY) { 612 error = EADDRNOTAVAIL; 613 break; 614 } 615 memset(&si, 0, sizeof(si)); 616 si.sin_family = AF_INET; 617 si.sin_len = sizeof(struct sockaddr_in); 618 si.sin_addr.s_addr = sc->g_src.s_addr; 619 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 620 break; 621 case SIOCGIFPDSTADDR: 622#ifdef INET6 623 case SIOCGIFPDSTADDR_IN6: 624#endif 625 if (sc->g_dst.s_addr == INADDR_ANY) { 626 error = EADDRNOTAVAIL; 627 break; 628 } 629 memset(&si, 0, sizeof(si)); 630 si.sin_family = AF_INET; 631 si.sin_len = sizeof(struct sockaddr_in); 632 si.sin_addr.s_addr = sc->g_dst.s_addr; 633 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 634 break; 635 default: 636 error = EINVAL; 637 break; 638 } 639 640 splx(s); 641 return (error); 642} 643 644/* 645 * computes a route to our destination that is not the one 646 * which would be taken by ip_output(), as this one will loop back to 647 * us. If the interface is p2p as a--->b, then a routing entry exists 648 * If we now send a packet to b (e.g. ping b), this will come down here 649 * gets src=a, dst=b tacked on and would from ip_output() sent back to 650 * if_gre. 651 * Goal here is to compute a route to b that is less specific than 652 * a-->b. We know that this one exists as in normal operation we have 653 * at least a default route which matches. 654 */ 655static int 656gre_compute_route(struct gre_softc *sc) 657{ 658 struct route *ro; 659 u_int32_t a, b, c; 660 661 ro = &sc->route; 662 663 memset(ro, 0, sizeof(struct route)); 664 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 665 ro->ro_dst.sa_family = AF_INET; 666 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 667 668 /* 669 * toggle last bit, so our interface is not found, but a less 670 * specific route. I'd rather like to specify a shorter mask, 671 * but this is not possible. Should work though. XXX 672 * there is a simpler way ... 673 */ 674 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) { 675 a = ntohl(sc->g_dst.s_addr); 676 b = a & 0x01; 677 c = a & 0xfffffffe; 678 b = b ^ 0x01; 679 a = b | c; 680 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 681 = htonl(a); 682 } 683 684#ifdef DIAGNOSTIC 685 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)), 686 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 687#endif 688 689 rtalloc(ro); 690 691 /* 692 * check if this returned a route at all and this route is no 693 * recursion to ourself 694 */ 695 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 696#ifdef DIAGNOSTIC 697 if (ro->ro_rt == NULL) 698 printf(" - no route found!\n"); 699 else 700 printf(" - route loops back to ourself!\n"); 701#endif 702 return EADDRNOTAVAIL; 703 } 704 705 /* 706 * now change it back - else ip_output will just drop 707 * the route and search one to this interface ... 708 */ 709 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) 710 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 711 712#ifdef DIAGNOSTIC 713 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 714 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 715 printf("\n"); 716#endif 717 718 return 0; 719} 720 721/* 722 * do a checksum of a buffer - much like in_cksum, which operates on 723 * mbufs. 724 */ 725u_int16_t 726gre_in_cksum(u_int16_t *p, u_int len) 727{ 728 u_int32_t sum = 0; 729 int nwords = len >> 1; 730 731 while (nwords-- != 0) 732 sum += *p++; 733 734 if (len & 1) { 735 union { 736 u_short w; 737 u_char c[2]; 738 } u; 739 u.c[0] = *(u_char *)p; 740 u.c[1] = 0; 741 sum += u.w; 742 } 743 744 /* end-around-carry */ 745 sum = (sum >> 16) + (sum & 0xffff); 746 sum += (sum >> 16); 747 return (~sum); 748} 749 750static int 751gremodevent(module_t mod, int type, void *data) 752{ 753 struct gre_softc *sc; 754 755 switch (type) { 756 case MOD_LOAD: 757 greattach(); 758 break; 759 case MOD_UNLOAD: 760 if_clone_detach(&gre_cloner); 761 762 mtx_lock(&gre_mtx); 763 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) { 764 LIST_REMOVE(sc, sc_list); 765 mtx_unlock(&gre_mtx); 766 gre_destroy(sc); 767 mtx_lock(&gre_mtx); 768 } 769 mtx_unlock(&gre_mtx); 770 mtx_destroy(&gre_mtx); 771 break; 772 default: 773 return EOPNOTSUPP; 774 } 775 return 0; 776} 777 778static moduledata_t gre_mod = { 779 "if_gre", 780 gremodevent, 781 0 782}; 783 784DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 785MODULE_VERSION(if_gre, 1); 786