if_gre.c revision 148887
1/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ 2/* $FreeBSD: head/sys/net/if_gre.c 148887 2005-08-09 10:20:02Z rwatson $ */ 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 */ 102struct mtx gre_mtx; 103static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 104 105struct gre_softc_head gre_softc_list; 106 107static int gre_clone_create(struct if_clone *, int); 108static void gre_clone_destroy(struct ifnet *); 109static int gre_ioctl(struct ifnet *, u_long, caddr_t); 110static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 111 struct rtentry *rt); 112 113IFC_SIMPLE_DECLARE(gre, 0); 114 115static int gre_compute_route(struct gre_softc *sc); 116 117static void greattach(void); 118 119#ifdef INET 120extern struct domain inetdomain; 121static const struct protosw in_gre_protosw = 122{ SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 123 (pr_input_t*)gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 124 0, 125 0, 0, 0, 0, 126 &rip_usrreqs 127}; 128static const struct protosw in_mobile_protosw = 129{ SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 130 (pr_input_t*)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 137SYSCTL_DECL(_net_link); 138SYSCTL_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 151static int max_gre_nesting = MAX_GRE_NEST; 152SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 153 &max_gre_nesting, 0, "Max nested tunnels"); 154 155/* ARGSUSED */ 156static void 157greattach(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 165static int 166gre_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 GRE2IFP(sc) = if_alloc(IFT_TUNNEL); 175 if (GRE2IFP(sc) == NULL) { 176 free(sc, M_GRE); 177 return (ENOSPC); 178 } 179 180 GRE2IFP(sc)->if_softc = sc; 181 if_initname(GRE2IFP(sc), ifc->ifc_name, unit); 182 183 GRE2IFP(sc)->if_snd.ifq_maxlen = IFQ_MAXLEN; 184 GRE2IFP(sc)->if_addrlen = 0; 185 GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */ 186 GRE2IFP(sc)->if_mtu = GREMTU; 187 GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 188 GRE2IFP(sc)->if_output = gre_output; 189 GRE2IFP(sc)->if_ioctl = gre_ioctl; 190 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 191 sc->g_proto = IPPROTO_GRE; 192 GRE2IFP(sc)->if_flags |= IFF_LINK0; 193 sc->encap = NULL; 194 sc->called = 0; 195 sc->wccp_ver = WCCP_V1; 196 if_attach(GRE2IFP(sc)); 197 bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t)); 198 mtx_lock(&gre_mtx); 199 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 200 mtx_unlock(&gre_mtx); 201 return (0); 202} 203 204static void 205gre_destroy(struct gre_softc *sc) 206{ 207 208#ifdef INET 209 if (sc->encap != NULL) 210 encap_detach(sc->encap); 211#endif 212 bpfdetach(GRE2IFP(sc)); 213 if_detach(GRE2IFP(sc)); 214 if_free(GRE2IFP(sc)); 215 free(sc, M_GRE); 216} 217 218static void 219gre_clone_destroy(ifp) 220 struct ifnet *ifp; 221{ 222 struct gre_softc *sc = ifp->if_softc; 223 224 mtx_lock(&gre_mtx); 225 LIST_REMOVE(sc, sc_list); 226 mtx_unlock(&gre_mtx); 227 gre_destroy(sc); 228} 229 230/* 231 * The output routine. Takes a packet and encapsulates it in the protocol 232 * given by sc->g_proto. See also RFC 1701 and RFC 2004 233 */ 234static int 235gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 236 struct rtentry *rt) 237{ 238 int error = 0; 239 struct gre_softc *sc = ifp->if_softc; 240 struct greip *gh; 241 struct ip *ip; 242 u_short ip_id = 0; 243 uint8_t ip_tos = 0; 244 u_int16_t etype = 0; 245 struct mobile_h mob_h; 246 u_int32_t af; 247 248 /* 249 * gre may cause infinite recursion calls when misconfigured. 250 * We'll prevent this by introducing upper limit. 251 */ 252 if (++(sc->called) > max_gre_nesting) { 253 printf("%s: gre_output: recursively called too many " 254 "times(%d)\n", if_name(GRE2IFP(sc)), sc->called); 255 m_freem(m); 256 error = EIO; /* is there better errno? */ 257 goto end; 258 } 259 260 if (!((ifp->if_flags & IFF_UP) && 261 (ifp->if_drv_flags & IFF_DRV_RUNNING)) || 262 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 263 m_freem(m); 264 error = ENETDOWN; 265 goto end; 266 } 267 268 gh = NULL; 269 ip = NULL; 270 271 /* BPF writes need to be handled specially. */ 272 if (dst->sa_family == AF_UNSPEC) { 273 bcopy(dst->sa_data, &af, sizeof(af)); 274 dst->sa_family = af; 275 } 276 277 if (ifp->if_bpf) { 278 af = dst->sa_family; 279 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 280 } 281 282 m->m_flags &= ~(M_BCAST|M_MCAST); 283 284 if (sc->g_proto == IPPROTO_MOBILE) { 285 if (dst->sa_family == AF_INET) { 286 struct mbuf *m0; 287 int msiz; 288 289 ip = mtod(m, struct ip *); 290 291 /* 292 * RFC2004 specifies that fragmented diagrams shouldn't 293 * be encapsulated. 294 */ 295 if ((ip->ip_off & IP_MF) != 0) { 296 _IF_DROP(&ifp->if_snd); 297 m_freem(m); 298 error = EINVAL; /* is there better errno? */ 299 goto end; 300 } 301 memset(&mob_h, 0, MOB_H_SIZ_L); 302 mob_h.proto = (ip->ip_p) << 8; 303 mob_h.odst = ip->ip_dst.s_addr; 304 ip->ip_dst.s_addr = sc->g_dst.s_addr; 305 306 /* 307 * If the packet comes from our host, we only change 308 * the destination address in the IP header. 309 * Else we also need to save and change the source 310 */ 311 if (in_hosteq(ip->ip_src, sc->g_src)) { 312 msiz = MOB_H_SIZ_S; 313 } else { 314 mob_h.proto |= MOB_H_SBIT; 315 mob_h.osrc = ip->ip_src.s_addr; 316 ip->ip_src.s_addr = sc->g_src.s_addr; 317 msiz = MOB_H_SIZ_L; 318 } 319 mob_h.proto = htons(mob_h.proto); 320 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 321 322 if ((m->m_data - msiz) < m->m_pktdat) { 323 /* need new mbuf */ 324 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 325 if (m0 == NULL) { 326 _IF_DROP(&ifp->if_snd); 327 m_freem(m); 328 error = ENOBUFS; 329 goto end; 330 } 331 m0->m_next = m; 332 m->m_data += sizeof(struct ip); 333 m->m_len -= sizeof(struct ip); 334 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 335 m0->m_len = msiz + sizeof(struct ip); 336 m0->m_data += max_linkhdr; 337 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 338 sizeof(struct ip)); 339 m = m0; 340 } else { /* we have some space left in the old one */ 341 m->m_data -= msiz; 342 m->m_len += msiz; 343 m->m_pkthdr.len += msiz; 344 bcopy(ip, mtod(m, caddr_t), 345 sizeof(struct ip)); 346 } 347 ip = mtod(m, struct ip *); 348 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 349 ip->ip_len = ntohs(ip->ip_len) + msiz; 350 } else { /* AF_INET */ 351 _IF_DROP(&ifp->if_snd); 352 m_freem(m); 353 error = EINVAL; 354 goto end; 355 } 356 } else if (sc->g_proto == IPPROTO_GRE) { 357 switch (dst->sa_family) { 358 case AF_INET: 359 ip = mtod(m, struct ip *); 360 ip_tos = ip->ip_tos; 361 ip_id = ip->ip_id; 362 etype = ETHERTYPE_IP; 363 break; 364#ifdef INET6 365 case AF_INET6: 366 ip_id = ip_newid(); 367 etype = ETHERTYPE_IPV6; 368 break; 369#endif 370#ifdef NETATALK 371 case AF_APPLETALK: 372 etype = ETHERTYPE_ATALK; 373 break; 374#endif 375 default: 376 _IF_DROP(&ifp->if_snd); 377 m_freem(m); 378 error = EAFNOSUPPORT; 379 goto end; 380 } 381 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 382 } else { 383 _IF_DROP(&ifp->if_snd); 384 m_freem(m); 385 error = EINVAL; 386 goto end; 387 } 388 389 if (m == NULL) { /* mbuf allocation failed */ 390 _IF_DROP(&ifp->if_snd); 391 error = ENOBUFS; 392 goto end; 393 } 394 395 gh = mtod(m, struct greip *); 396 if (sc->g_proto == IPPROTO_GRE) { 397 /* we don't have any GRE flags for now */ 398 memset((void *)gh, 0, sizeof(struct greip)); 399 gh->gi_ptype = htons(etype); 400 } 401 402 gh->gi_pr = sc->g_proto; 403 if (sc->g_proto != IPPROTO_MOBILE) { 404 gh->gi_src = sc->g_src; 405 gh->gi_dst = sc->g_dst; 406 ((struct ip*)gh)->ip_v = IPPROTO_IPV4; 407 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 408 ((struct ip*)gh)->ip_ttl = GRE_TTL; 409 ((struct ip*)gh)->ip_tos = ip_tos; 410 ((struct ip*)gh)->ip_id = ip_id; 411 gh->gi_len = m->m_pkthdr.len; 412 } 413 414 ifp->if_opackets++; 415 ifp->if_obytes += m->m_pkthdr.len; 416 /* 417 * Send it off and with IP_FORWARD flag to prevent it from 418 * overwriting the ip_id again. ip_id is already set to the 419 * ip_id of the encapsulated packet. 420 */ 421 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 422 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 423 end: 424 sc->called = 0; 425 if (error) 426 ifp->if_oerrors++; 427 return (error); 428} 429 430static int 431gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 432{ 433 struct ifreq *ifr = (struct ifreq *)data; 434 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 435 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 436 struct gre_softc *sc = ifp->if_softc; 437 int s; 438 struct sockaddr_in si; 439 struct sockaddr *sa = NULL; 440 int error; 441 struct sockaddr_in sp, sm, dp, dm; 442 443 error = 0; 444 445 s = splnet(); 446 switch (cmd) { 447 case SIOCSIFADDR: 448 ifp->if_flags |= IFF_UP; 449 break; 450 case SIOCSIFDSTADDR: 451 break; 452 case SIOCSIFFLAGS: 453 if ((error = suser(curthread)) != 0) 454 break; 455 if ((ifr->ifr_flags & IFF_LINK0) != 0) 456 sc->g_proto = IPPROTO_GRE; 457 else 458 sc->g_proto = IPPROTO_MOBILE; 459 if ((ifr->ifr_flags & IFF_LINK2) != 0) 460 sc->wccp_ver = WCCP_V2; 461 else 462 sc->wccp_ver = WCCP_V1; 463 goto recompute; 464 case SIOCSIFMTU: 465 if ((error = suser(curthread)) != 0) 466 break; 467 if (ifr->ifr_mtu < 576) { 468 error = EINVAL; 469 break; 470 } 471 ifp->if_mtu = ifr->ifr_mtu; 472 break; 473 case SIOCGIFMTU: 474 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu; 475 break; 476 case SIOCADDMULTI: 477 case SIOCDELMULTI: 478 if ((error = suser(curthread)) != 0) 479 break; 480 if (ifr == 0) { 481 error = EAFNOSUPPORT; 482 break; 483 } 484 switch (ifr->ifr_addr.sa_family) { 485#ifdef INET 486 case AF_INET: 487 break; 488#endif 489#ifdef INET6 490 case AF_INET6: 491 break; 492#endif 493 default: 494 error = EAFNOSUPPORT; 495 break; 496 } 497 break; 498 case GRESPROTO: 499 if ((error = suser(curthread)) != 0) 500 break; 501 sc->g_proto = ifr->ifr_flags; 502 switch (sc->g_proto) { 503 case IPPROTO_GRE: 504 ifp->if_flags |= IFF_LINK0; 505 break; 506 case IPPROTO_MOBILE: 507 ifp->if_flags &= ~IFF_LINK0; 508 break; 509 default: 510 error = EPROTONOSUPPORT; 511 break; 512 } 513 goto recompute; 514 case GREGPROTO: 515 ifr->ifr_flags = sc->g_proto; 516 break; 517 case GRESADDRS: 518 case GRESADDRD: 519 if ((error = suser(curthread)) != 0) 520 break; 521 /* 522 * set tunnel endpoints, compute a less specific route 523 * to the remote end and mark if as up 524 */ 525 sa = &ifr->ifr_addr; 526 if (cmd == GRESADDRS) 527 sc->g_src = (satosin(sa))->sin_addr; 528 if (cmd == GRESADDRD) 529 sc->g_dst = (satosin(sa))->sin_addr; 530 recompute: 531#ifdef INET 532 if (sc->encap != NULL) { 533 encap_detach(sc->encap); 534 sc->encap = NULL; 535 } 536#endif 537 if ((sc->g_src.s_addr != INADDR_ANY) && 538 (sc->g_dst.s_addr != INADDR_ANY)) { 539 bzero(&sp, sizeof(sp)); 540 bzero(&sm, sizeof(sm)); 541 bzero(&dp, sizeof(dp)); 542 bzero(&dm, sizeof(dm)); 543 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 544 sizeof(struct sockaddr_in); 545 sp.sin_family = sm.sin_family = dp.sin_family = 546 dm.sin_family = AF_INET; 547 sp.sin_addr = sc->g_src; 548 dp.sin_addr = sc->g_dst; 549 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 550 INADDR_BROADCAST; 551#ifdef INET 552 sc->encap = encap_attach(AF_INET, sc->g_proto, 553 sintosa(&sp), sintosa(&sm), sintosa(&dp), 554 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 555 &in_gre_protosw : &in_mobile_protosw, sc); 556 if (sc->encap == NULL) 557 printf("%s: unable to attach encap\n", 558 if_name(GRE2IFP(sc))); 559#endif 560 if (sc->route.ro_rt != 0) /* free old route */ 561 RTFREE(sc->route.ro_rt); 562 if (gre_compute_route(sc) == 0) 563 ifp->if_drv_flags |= IFF_DRV_RUNNING; 564 else 565 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 566 } 567 break; 568 case GREGADDRS: 569 memset(&si, 0, sizeof(si)); 570 si.sin_family = AF_INET; 571 si.sin_len = sizeof(struct sockaddr_in); 572 si.sin_addr.s_addr = sc->g_src.s_addr; 573 sa = sintosa(&si); 574 ifr->ifr_addr = *sa; 575 break; 576 case GREGADDRD: 577 memset(&si, 0, sizeof(si)); 578 si.sin_family = AF_INET; 579 si.sin_len = sizeof(struct sockaddr_in); 580 si.sin_addr.s_addr = sc->g_dst.s_addr; 581 sa = sintosa(&si); 582 ifr->ifr_addr = *sa; 583 break; 584 case SIOCSIFPHYADDR: 585 if ((error = suser(curthread)) != 0) 586 break; 587 if (aifr->ifra_addr.sin_family != AF_INET || 588 aifr->ifra_dstaddr.sin_family != AF_INET) { 589 error = EAFNOSUPPORT; 590 break; 591 } 592 if (aifr->ifra_addr.sin_len != sizeof(si) || 593 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 594 error = EINVAL; 595 break; 596 } 597 sc->g_src = aifr->ifra_addr.sin_addr; 598 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 599 goto recompute; 600 case SIOCSLIFPHYADDR: 601 if ((error = suser(curthread)) != 0) 602 break; 603 if (lifr->addr.ss_family != AF_INET || 604 lifr->dstaddr.ss_family != AF_INET) { 605 error = EAFNOSUPPORT; 606 break; 607 } 608 if (lifr->addr.ss_len != sizeof(si) || 609 lifr->dstaddr.ss_len != sizeof(si)) { 610 error = EINVAL; 611 break; 612 } 613 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 614 sc->g_dst = 615 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 616 goto recompute; 617 case SIOCDIFPHYADDR: 618 if ((error = suser(curthread)) != 0) 619 break; 620 sc->g_src.s_addr = INADDR_ANY; 621 sc->g_dst.s_addr = INADDR_ANY; 622 goto recompute; 623 case SIOCGLIFPHYADDR: 624 if (sc->g_src.s_addr == INADDR_ANY || 625 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_src.s_addr; 633 memcpy(&lifr->addr, &si, sizeof(si)); 634 si.sin_addr.s_addr = sc->g_dst.s_addr; 635 memcpy(&lifr->dstaddr, &si, sizeof(si)); 636 break; 637 case SIOCGIFPSRCADDR: 638#ifdef INET6 639 case SIOCGIFPSRCADDR_IN6: 640#endif 641 if (sc->g_src.s_addr == INADDR_ANY) { 642 error = EADDRNOTAVAIL; 643 break; 644 } 645 memset(&si, 0, sizeof(si)); 646 si.sin_family = AF_INET; 647 si.sin_len = sizeof(struct sockaddr_in); 648 si.sin_addr.s_addr = sc->g_src.s_addr; 649 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 650 break; 651 case SIOCGIFPDSTADDR: 652#ifdef INET6 653 case SIOCGIFPDSTADDR_IN6: 654#endif 655 if (sc->g_dst.s_addr == INADDR_ANY) { 656 error = EADDRNOTAVAIL; 657 break; 658 } 659 memset(&si, 0, sizeof(si)); 660 si.sin_family = AF_INET; 661 si.sin_len = sizeof(struct sockaddr_in); 662 si.sin_addr.s_addr = sc->g_dst.s_addr; 663 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 664 break; 665 default: 666 error = EINVAL; 667 break; 668 } 669 670 splx(s); 671 return (error); 672} 673 674/* 675 * computes a route to our destination that is not the one 676 * which would be taken by ip_output(), as this one will loop back to 677 * us. If the interface is p2p as a--->b, then a routing entry exists 678 * If we now send a packet to b (e.g. ping b), this will come down here 679 * gets src=a, dst=b tacked on and would from ip_output() sent back to 680 * if_gre. 681 * Goal here is to compute a route to b that is less specific than 682 * a-->b. We know that this one exists as in normal operation we have 683 * at least a default route which matches. 684 */ 685static int 686gre_compute_route(struct gre_softc *sc) 687{ 688 struct route *ro; 689 u_int32_t a, b, c; 690 691 ro = &sc->route; 692 693 memset(ro, 0, sizeof(struct route)); 694 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 695 ro->ro_dst.sa_family = AF_INET; 696 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 697 698 /* 699 * toggle last bit, so our interface is not found, but a less 700 * specific route. I'd rather like to specify a shorter mask, 701 * but this is not possible. Should work though. XXX 702 * there is a simpler way ... 703 */ 704 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) { 705 a = ntohl(sc->g_dst.s_addr); 706 b = a & 0x01; 707 c = a & 0xfffffffe; 708 b = b ^ 0x01; 709 a = b | c; 710 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 711 = htonl(a); 712 } 713 714#ifdef DIAGNOSTIC 715 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)), 716 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 717#endif 718 719 rtalloc(ro); 720 721 /* 722 * check if this returned a route at all and this route is no 723 * recursion to ourself 724 */ 725 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 726#ifdef DIAGNOSTIC 727 if (ro->ro_rt == NULL) 728 printf(" - no route found!\n"); 729 else 730 printf(" - route loops back to ourself!\n"); 731#endif 732 return EADDRNOTAVAIL; 733 } 734 735 /* 736 * now change it back - else ip_output will just drop 737 * the route and search one to this interface ... 738 */ 739 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) 740 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 741 742#ifdef DIAGNOSTIC 743 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 744 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 745 printf("\n"); 746#endif 747 748 return 0; 749} 750 751/* 752 * do a checksum of a buffer - much like in_cksum, which operates on 753 * mbufs. 754 */ 755u_int16_t 756gre_in_cksum(u_int16_t *p, u_int len) 757{ 758 u_int32_t sum = 0; 759 int nwords = len >> 1; 760 761 while (nwords-- != 0) 762 sum += *p++; 763 764 if (len & 1) { 765 union { 766 u_short w; 767 u_char c[2]; 768 } u; 769 u.c[0] = *(u_char *)p; 770 u.c[1] = 0; 771 sum += u.w; 772 } 773 774 /* end-around-carry */ 775 sum = (sum >> 16) + (sum & 0xffff); 776 sum += (sum >> 16); 777 return (~sum); 778} 779 780static int 781gremodevent(module_t mod, int type, void *data) 782{ 783 struct gre_softc *sc; 784 785 switch (type) { 786 case MOD_LOAD: 787 greattach(); 788 break; 789 case MOD_UNLOAD: 790 if_clone_detach(&gre_cloner); 791 792 mtx_lock(&gre_mtx); 793 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) { 794 LIST_REMOVE(sc, sc_list); 795 mtx_unlock(&gre_mtx); 796 gre_destroy(sc); 797 mtx_lock(&gre_mtx); 798 } 799 mtx_unlock(&gre_mtx); 800 mtx_destroy(&gre_mtx); 801 break; 802 default: 803 return EOPNOTSUPP; 804 } 805 return 0; 806} 807 808static moduledata_t gre_mod = { 809 "if_gre", 810 gremodevent, 811 0 812}; 813 814DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 815MODULE_VERSION(if_gre, 1); 816