if_gre.c revision 128580
1/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ 2/* $FreeBSD: head/sys/net/if_gre.c 128580 2004-04-23 16:10:23Z andre $ */ 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/mbuf.h> 57#include <sys/protosw.h> 58#include <sys/socket.h> 59#include <sys/sockio.h> 60#include <sys/sysctl.h> 61#include <sys/systm.h> 62 63#include <net/ethernet.h> 64#include <net/if.h> 65#include <net/if_types.h> 66#include <net/route.h> 67 68#ifdef INET 69#include <netinet/in.h> 70#include <netinet/in_systm.h> 71#include <netinet/in_var.h> 72#include <netinet/ip.h> 73#include <netinet/ip_gre.h> 74#include <netinet/ip_var.h> 75#include <netinet/ip_encap.h> 76#else 77#error "Huh? if_gre without inet?" 78#endif 79 80#include <net/bpf.h> 81 82#include <net/net_osdep.h> 83#include <net/if_gre.h> 84 85/* 86 * It is not easy to calculate the right value for a GRE MTU. 87 * We leave this task to the admin and use the same default that 88 * other vendors use. 89 */ 90#define GREMTU 1476 91 92#define GRENAME "gre" 93 94/* 95 * gre_mtx protects all global variables in if_gre.c. 96 * XXX: gre_softc data not protected yet. 97 */ 98struct mtx gre_mtx; 99static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 100 101struct gre_softc_head gre_softc_list; 102 103static int gre_clone_create(struct if_clone *, int); 104static void gre_clone_destroy(struct ifnet *); 105static int gre_ioctl(struct ifnet *, u_long, caddr_t); 106static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 107 struct rtentry *rt); 108 109static struct if_clone gre_cloner = 110 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 111 112static int gre_compute_route(struct gre_softc *sc); 113 114static void greattach(void); 115 116#ifdef INET 117extern struct domain inetdomain; 118static const struct protosw in_gre_protosw = 119{ SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 120 (pr_input_t*)gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 121 0, 122 0, 0, 0, 0, 123 &rip_usrreqs 124}; 125static const struct protosw in_mobile_protosw = 126{ SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 127 (pr_input_t*)gre_mobile_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 128 0, 129 0, 0, 0, 0, 130 &rip_usrreqs 131}; 132#endif 133 134SYSCTL_DECL(_net_link); 135SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0, 136 "Generic Routing Encapsulation"); 137#ifndef MAX_GRE_NEST 138/* 139 * This macro controls the default upper limitation on nesting of gre tunnels. 140 * Since, setting a large value to this macro with a careless configuration 141 * may introduce system crash, we don't allow any nestings by default. 142 * If you need to configure nested gre tunnels, you can define this macro 143 * in your kernel configuration file. However, if you do so, please be 144 * careful to configure the tunnels so that it won't make a loop. 145 */ 146#define MAX_GRE_NEST 1 147#endif 148static int max_gre_nesting = MAX_GRE_NEST; 149SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 150 &max_gre_nesting, 0, "Max nested tunnels"); 151 152/* ARGSUSED */ 153static void 154greattach(void) 155{ 156 157 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF); 158 LIST_INIT(&gre_softc_list); 159 if_clone_attach(&gre_cloner); 160} 161 162static int 163gre_clone_create(ifc, unit) 164 struct if_clone *ifc; 165 int unit; 166{ 167 struct gre_softc *sc; 168 169 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 170 memset(sc, 0, sizeof(struct gre_softc)); 171 172 if_initname(&sc->sc_if, ifc->ifc_name, unit); 173 sc->sc_if.if_softc = sc; 174 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 175 sc->sc_if.if_type = IFT_TUNNEL; 176 sc->sc_if.if_addrlen = 0; 177 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 178 sc->sc_if.if_mtu = GREMTU; 179 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 180 sc->sc_if.if_output = gre_output; 181 sc->sc_if.if_ioctl = gre_ioctl; 182 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 183 sc->g_proto = IPPROTO_GRE; 184 sc->sc_if.if_flags |= IFF_LINK0; 185 sc->encap = NULL; 186 sc->called = 0; 187 sc->wccp_ver = WCCP_V1; 188 if_attach(&sc->sc_if); 189 bpfattach(&sc->sc_if, 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(&sc->sc_if); 205 if_detach(&sc->sc_if); 206 free(sc, M_GRE); 207} 208 209static void 210gre_clone_destroy(ifp) 211 struct ifnet *ifp; 212{ 213 struct gre_softc *sc = ifp->if_softc; 214 215 mtx_lock(&gre_mtx); 216 LIST_REMOVE(sc, sc_list); 217 mtx_unlock(&gre_mtx); 218 gre_destroy(sc); 219} 220 221/* 222 * The output routine. Takes a packet and encapsulates it in the protocol 223 * given by sc->g_proto. See also RFC 1701 and RFC 2004 224 */ 225static int 226gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 227 struct rtentry *rt) 228{ 229 int error = 0; 230 struct gre_softc *sc = ifp->if_softc; 231 struct greip *gh; 232 struct ip *ip; 233 u_int16_t etype = 0; 234 struct mobile_h mob_h; 235 236 /* 237 * gre may cause infinite recursion calls when misconfigured. 238 * We'll prevent this by introducing upper limit. 239 */ 240 if (++(sc->called) > max_gre_nesting) { 241 printf("%s: gre_output: recursively called too many " 242 "times(%d)\n", if_name(&sc->sc_if), sc->called); 243 m_freem(m); 244 error = EIO; /* is there better errno? */ 245 goto end; 246 } 247 248 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 249 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 250 m_freem(m); 251 error = ENETDOWN; 252 goto end; 253 } 254 255 gh = NULL; 256 ip = NULL; 257 258 if (ifp->if_bpf) { 259 u_int32_t af = dst->sa_family; 260 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 261 } 262 263 m->m_flags &= ~(M_BCAST|M_MCAST); 264 265 if (sc->g_proto == IPPROTO_MOBILE) { 266 if (dst->sa_family == AF_INET) { 267 struct mbuf *m0; 268 int msiz; 269 270 ip = mtod(m, struct ip *); 271 272 /* 273 * RFC2004 specifies that fragmented diagrams shouldn't 274 * be encapsulated. 275 */ 276 if ((ip->ip_off & IP_MF) != 0) { 277 _IF_DROP(&ifp->if_snd); 278 m_freem(m); 279 error = EINVAL; /* is there better errno? */ 280 goto end; 281 } 282 memset(&mob_h, 0, MOB_H_SIZ_L); 283 mob_h.proto = (ip->ip_p) << 8; 284 mob_h.odst = ip->ip_dst.s_addr; 285 ip->ip_dst.s_addr = sc->g_dst.s_addr; 286 287 /* 288 * If the packet comes from our host, we only change 289 * the destination address in the IP header. 290 * Else we also need to save and change the source 291 */ 292 if (in_hosteq(ip->ip_src, sc->g_src)) { 293 msiz = MOB_H_SIZ_S; 294 } else { 295 mob_h.proto |= MOB_H_SBIT; 296 mob_h.osrc = ip->ip_src.s_addr; 297 ip->ip_src.s_addr = sc->g_src.s_addr; 298 msiz = MOB_H_SIZ_L; 299 } 300 mob_h.proto = htons(mob_h.proto); 301 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 302 303 if ((m->m_data - msiz) < m->m_pktdat) { 304 /* need new mbuf */ 305 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 306 if (m0 == NULL) { 307 _IF_DROP(&ifp->if_snd); 308 m_freem(m); 309 error = ENOBUFS; 310 goto end; 311 } 312 m0->m_next = m; 313 m->m_data += sizeof(struct ip); 314 m->m_len -= sizeof(struct ip); 315 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 316 m0->m_len = msiz + sizeof(struct ip); 317 m0->m_data += max_linkhdr; 318 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 319 sizeof(struct ip)); 320 m = m0; 321 } else { /* we have some space left in the old one */ 322 m->m_data -= msiz; 323 m->m_len += msiz; 324 m->m_pkthdr.len += msiz; 325 bcopy(ip, mtod(m, caddr_t), 326 sizeof(struct ip)); 327 } 328 ip = mtod(m, struct ip *); 329 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 330 ip->ip_len = ntohs(ip->ip_len) + msiz; 331 } else { /* AF_INET */ 332 _IF_DROP(&ifp->if_snd); 333 m_freem(m); 334 error = EINVAL; 335 goto end; 336 } 337 } else if (sc->g_proto == IPPROTO_GRE) { 338 switch (dst->sa_family) { 339 case AF_INET: 340 ip = mtod(m, struct ip *); 341 etype = ETHERTYPE_IP; 342 break; 343#ifdef NETATALK 344 case AF_APPLETALK: 345 etype = ETHERTYPE_ATALK; 346 break; 347#endif 348 default: 349 _IF_DROP(&ifp->if_snd); 350 m_freem(m); 351 error = EAFNOSUPPORT; 352 goto end; 353 } 354 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 355 } else { 356 _IF_DROP(&ifp->if_snd); 357 m_freem(m); 358 error = EINVAL; 359 goto end; 360 } 361 362 if (m == NULL) { /* mbuf allocation failed */ 363 _IF_DROP(&ifp->if_snd); 364 error = ENOBUFS; 365 goto end; 366 } 367 368 gh = mtod(m, struct greip *); 369 if (sc->g_proto == IPPROTO_GRE) { 370 /* we don't have any GRE flags for now */ 371 memset((void *)gh, 0, sizeof(struct greip)); 372 gh->gi_ptype = htons(etype); 373 } 374 375 gh->gi_pr = sc->g_proto; 376 if (sc->g_proto != IPPROTO_MOBILE) { 377 gh->gi_src = sc->g_src; 378 gh->gi_dst = sc->g_dst; 379 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 380 ((struct ip*)gh)->ip_ttl = GRE_TTL; 381 ((struct ip*)gh)->ip_tos = ip->ip_tos; 382 ((struct ip*)gh)->ip_id = ip->ip_id; 383 gh->gi_len = m->m_pkthdr.len; 384 } 385 386 ifp->if_opackets++; 387 ifp->if_obytes += m->m_pkthdr.len; 388 /* send it off */ 389 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 390 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 391 end: 392 sc->called = 0; 393 if (error) 394 ifp->if_oerrors++; 395 return (error); 396} 397 398static int 399gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 400{ 401 struct ifreq *ifr = (struct ifreq *)data; 402 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 403 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 404 struct gre_softc *sc = ifp->if_softc; 405 int s; 406 struct sockaddr_in si; 407 struct sockaddr *sa = NULL; 408 int error; 409 struct sockaddr_in sp, sm, dp, dm; 410 411 error = 0; 412 413 s = splnet(); 414 switch (cmd) { 415 case SIOCSIFADDR: 416 ifp->if_flags |= IFF_UP; 417 break; 418 case SIOCSIFDSTADDR: 419 break; 420 case SIOCSIFFLAGS: 421 if ((error = suser(curthread)) != 0) 422 break; 423 if ((ifr->ifr_flags & IFF_LINK0) != 0) 424 sc->g_proto = IPPROTO_GRE; 425 else 426 sc->g_proto = IPPROTO_MOBILE; 427 if ((ifr->ifr_flags & IFF_LINK2) != 0) 428 sc->wccp_ver = WCCP_V2; 429 else 430 sc->wccp_ver = WCCP_V1; 431 goto recompute; 432 case SIOCSIFMTU: 433 if ((error = suser(curthread)) != 0) 434 break; 435 if (ifr->ifr_mtu < 576) { 436 error = EINVAL; 437 break; 438 } 439 ifp->if_mtu = ifr->ifr_mtu; 440 break; 441 case SIOCGIFMTU: 442 ifr->ifr_mtu = sc->sc_if.if_mtu; 443 break; 444 case SIOCADDMULTI: 445 case SIOCDELMULTI: 446 if ((error = suser(curthread)) != 0) 447 break; 448 if (ifr == 0) { 449 error = EAFNOSUPPORT; 450 break; 451 } 452 switch (ifr->ifr_addr.sa_family) { 453#ifdef INET 454 case AF_INET: 455 break; 456#endif 457 default: 458 error = EAFNOSUPPORT; 459 break; 460 } 461 break; 462 case GRESPROTO: 463 if ((error = suser(curthread)) != 0) 464 break; 465 sc->g_proto = ifr->ifr_flags; 466 switch (sc->g_proto) { 467 case IPPROTO_GRE: 468 ifp->if_flags |= IFF_LINK0; 469 break; 470 case IPPROTO_MOBILE: 471 ifp->if_flags &= ~IFF_LINK0; 472 break; 473 default: 474 error = EPROTONOSUPPORT; 475 break; 476 } 477 goto recompute; 478 case GREGPROTO: 479 ifr->ifr_flags = sc->g_proto; 480 break; 481 case GRESADDRS: 482 case GRESADDRD: 483 if ((error = suser(curthread)) != 0) 484 break; 485 /* 486 * set tunnel endpoints, compute a less specific route 487 * to the remote end and mark if as up 488 */ 489 sa = &ifr->ifr_addr; 490 if (cmd == GRESADDRS) 491 sc->g_src = (satosin(sa))->sin_addr; 492 if (cmd == GRESADDRD) 493 sc->g_dst = (satosin(sa))->sin_addr; 494 recompute: 495#ifdef INET 496 if (sc->encap != NULL) { 497 encap_detach(sc->encap); 498 sc->encap = NULL; 499 } 500#endif 501 if ((sc->g_src.s_addr != INADDR_ANY) && 502 (sc->g_dst.s_addr != INADDR_ANY)) { 503 bzero(&sp, sizeof(sp)); 504 bzero(&sm, sizeof(sm)); 505 bzero(&dp, sizeof(dp)); 506 bzero(&dm, sizeof(dm)); 507 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 508 sizeof(struct sockaddr_in); 509 sp.sin_family = sm.sin_family = dp.sin_family = 510 dm.sin_family = AF_INET; 511 sp.sin_addr = sc->g_src; 512 dp.sin_addr = sc->g_dst; 513 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 514 INADDR_BROADCAST; 515#ifdef INET 516 sc->encap = encap_attach(AF_INET, sc->g_proto, 517 sintosa(&sp), sintosa(&sm), sintosa(&dp), 518 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 519 &in_gre_protosw : &in_mobile_protosw, sc); 520 if (sc->encap == NULL) 521 printf("%s: unable to attach encap\n", 522 if_name(&sc->sc_if)); 523#endif 524 if (sc->route.ro_rt != 0) /* free old route */ 525 RTFREE(sc->route.ro_rt); 526 if (gre_compute_route(sc) == 0) 527 ifp->if_flags |= IFF_RUNNING; 528 else 529 ifp->if_flags &= ~IFF_RUNNING; 530 } 531 break; 532 case GREGADDRS: 533 memset(&si, 0, sizeof(si)); 534 si.sin_family = AF_INET; 535 si.sin_len = sizeof(struct sockaddr_in); 536 si.sin_addr.s_addr = sc->g_src.s_addr; 537 sa = sintosa(&si); 538 ifr->ifr_addr = *sa; 539 break; 540 case GREGADDRD: 541 memset(&si, 0, sizeof(si)); 542 si.sin_family = AF_INET; 543 si.sin_len = sizeof(struct sockaddr_in); 544 si.sin_addr.s_addr = sc->g_dst.s_addr; 545 sa = sintosa(&si); 546 ifr->ifr_addr = *sa; 547 break; 548 case SIOCSIFPHYADDR: 549 if ((error = suser(curthread)) != 0) 550 break; 551 if (aifr->ifra_addr.sin_family != AF_INET || 552 aifr->ifra_dstaddr.sin_family != AF_INET) { 553 error = EAFNOSUPPORT; 554 break; 555 } 556 if (aifr->ifra_addr.sin_len != sizeof(si) || 557 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 558 error = EINVAL; 559 break; 560 } 561 sc->g_src = aifr->ifra_addr.sin_addr; 562 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 563 goto recompute; 564 case SIOCSLIFPHYADDR: 565 if ((error = suser(curthread)) != 0) 566 break; 567 if (lifr->addr.ss_family != AF_INET || 568 lifr->dstaddr.ss_family != AF_INET) { 569 error = EAFNOSUPPORT; 570 break; 571 } 572 if (lifr->addr.ss_len != sizeof(si) || 573 lifr->dstaddr.ss_len != sizeof(si)) { 574 error = EINVAL; 575 break; 576 } 577 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 578 sc->g_dst = 579 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 580 goto recompute; 581 case SIOCDIFPHYADDR: 582 if ((error = suser(curthread)) != 0) 583 break; 584 sc->g_src.s_addr = INADDR_ANY; 585 sc->g_dst.s_addr = INADDR_ANY; 586 goto recompute; 587 case SIOCGLIFPHYADDR: 588 if (sc->g_src.s_addr == INADDR_ANY || 589 sc->g_dst.s_addr == INADDR_ANY) { 590 error = EADDRNOTAVAIL; 591 break; 592 } 593 memset(&si, 0, sizeof(si)); 594 si.sin_family = AF_INET; 595 si.sin_len = sizeof(struct sockaddr_in); 596 si.sin_addr.s_addr = sc->g_src.s_addr; 597 memcpy(&lifr->addr, &si, sizeof(si)); 598 si.sin_addr.s_addr = sc->g_dst.s_addr; 599 memcpy(&lifr->dstaddr, &si, sizeof(si)); 600 break; 601 case SIOCGIFPSRCADDR: 602#ifdef INET6 603 case SIOCGIFPSRCADDR_IN6: 604#endif 605 if (sc->g_src.s_addr == INADDR_ANY) { 606 error = EADDRNOTAVAIL; 607 break; 608 } 609 memset(&si, 0, sizeof(si)); 610 si.sin_family = AF_INET; 611 si.sin_len = sizeof(struct sockaddr_in); 612 si.sin_addr.s_addr = sc->g_src.s_addr; 613 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 614 break; 615 case SIOCGIFPDSTADDR: 616#ifdef INET6 617 case SIOCGIFPDSTADDR_IN6: 618#endif 619 if (sc->g_dst.s_addr == INADDR_ANY) { 620 error = EADDRNOTAVAIL; 621 break; 622 } 623 memset(&si, 0, sizeof(si)); 624 si.sin_family = AF_INET; 625 si.sin_len = sizeof(struct sockaddr_in); 626 si.sin_addr.s_addr = sc->g_dst.s_addr; 627 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 628 break; 629 default: 630 error = EINVAL; 631 break; 632 } 633 634 splx(s); 635 return (error); 636} 637 638/* 639 * computes a route to our destination that is not the one 640 * which would be taken by ip_output(), as this one will loop back to 641 * us. If the interface is p2p as a--->b, then a routing entry exists 642 * If we now send a packet to b (e.g. ping b), this will come down here 643 * gets src=a, dst=b tacked on and would from ip_output() sent back to 644 * if_gre. 645 * Goal here is to compute a route to b that is less specific than 646 * a-->b. We know that this one exists as in normal operation we have 647 * at least a default route which matches. 648 */ 649static int 650gre_compute_route(struct gre_softc *sc) 651{ 652 struct route *ro; 653 u_int32_t a, b, c; 654 655 ro = &sc->route; 656 657 memset(ro, 0, sizeof(struct route)); 658 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 659 ro->ro_dst.sa_family = AF_INET; 660 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 661 662 /* 663 * toggle last bit, so our interface is not found, but a less 664 * specific route. I'd rather like to specify a shorter mask, 665 * but this is not possible. Should work though. XXX 666 * there is a simpler way ... 667 */ 668 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 669 a = ntohl(sc->g_dst.s_addr); 670 b = a & 0x01; 671 c = a & 0xfffffffe; 672 b = b ^ 0x01; 673 a = b | c; 674 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 675 = htonl(a); 676 } 677 678#ifdef DIAGNOSTIC 679 printf("%s: searching for a route to %s", if_name(&sc->sc_if), 680 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 681#endif 682 683 rtalloc(ro); 684 685 /* 686 * check if this returned a route at all and this route is no 687 * recursion to ourself 688 */ 689 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 690#ifdef DIAGNOSTIC 691 if (ro->ro_rt == NULL) 692 printf(" - no route found!\n"); 693 else 694 printf(" - route loops back to ourself!\n"); 695#endif 696 return EADDRNOTAVAIL; 697 } 698 699 /* 700 * now change it back - else ip_output will just drop 701 * the route and search one to this interface ... 702 */ 703 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 704 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 705 706#ifdef DIAGNOSTIC 707 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 708 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 709 printf("\n"); 710#endif 711 712 return 0; 713} 714 715/* 716 * do a checksum of a buffer - much like in_cksum, which operates on 717 * mbufs. 718 */ 719u_int16_t 720gre_in_cksum(u_int16_t *p, u_int len) 721{ 722 u_int32_t sum = 0; 723 int nwords = len >> 1; 724 725 while (nwords-- != 0) 726 sum += *p++; 727 728 if (len & 1) { 729 union { 730 u_short w; 731 u_char c[2]; 732 } u; 733 u.c[0] = *(u_char *)p; 734 u.c[1] = 0; 735 sum += u.w; 736 } 737 738 /* end-around-carry */ 739 sum = (sum >> 16) + (sum & 0xffff); 740 sum += (sum >> 16); 741 return (~sum); 742} 743 744static int 745gremodevent(module_t mod, int type, void *data) 746{ 747 struct gre_softc *sc; 748 749 switch (type) { 750 case MOD_LOAD: 751 greattach(); 752 break; 753 case MOD_UNLOAD: 754 if_clone_detach(&gre_cloner); 755 756 mtx_lock(&gre_mtx); 757 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) { 758 LIST_REMOVE(sc, sc_list); 759 mtx_unlock(&gre_mtx); 760 gre_destroy(sc); 761 mtx_lock(&gre_mtx); 762 } 763 mtx_unlock(&gre_mtx); 764 mtx_destroy(&gre_mtx); 765 break; 766 } 767 return 0; 768} 769 770static moduledata_t gre_mod = { 771 "if_gre", 772 gremodevent, 773 0 774}; 775 776DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 777MODULE_VERSION(if_gre, 1); 778