if_gre.c revision 152209
1/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */ 2/* $FreeBSD: head/sys/net/if_gre.c 152209 2005-11-08 20:08:34Z thompsa $ */ 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_clone_destroy(ifp) 206 struct ifnet *ifp; 207{ 208 struct gre_softc *sc = ifp->if_softc; 209 210 mtx_lock(&gre_mtx); 211 LIST_REMOVE(sc, sc_list); 212 mtx_unlock(&gre_mtx); 213 214#ifdef INET 215 if (sc->encap != NULL) 216 encap_detach(sc->encap); 217#endif 218 bpfdetach(ifp); 219 if_detach(ifp); 220 if_free(ifp); 221 free(sc, M_GRE); 222} 223 224/* 225 * The output routine. Takes a packet and encapsulates it in the protocol 226 * given by sc->g_proto. See also RFC 1701 and RFC 2004 227 */ 228static int 229gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 230 struct rtentry *rt) 231{ 232 int error = 0; 233 struct gre_softc *sc = ifp->if_softc; 234 struct greip *gh; 235 struct ip *ip; 236 u_short ip_id = 0; 237 uint8_t ip_tos = 0; 238 u_int16_t etype = 0; 239 struct mobile_h mob_h; 240 u_int32_t af; 241 242 /* 243 * gre may cause infinite recursion calls when misconfigured. 244 * We'll prevent this by introducing upper limit. 245 */ 246 if (++(sc->called) > max_gre_nesting) { 247 printf("%s: gre_output: recursively called too many " 248 "times(%d)\n", if_name(GRE2IFP(sc)), sc->called); 249 m_freem(m); 250 error = EIO; /* is there better errno? */ 251 goto end; 252 } 253 254 if (!((ifp->if_flags & IFF_UP) && 255 (ifp->if_drv_flags & IFF_DRV_RUNNING)) || 256 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 257 m_freem(m); 258 error = ENETDOWN; 259 goto end; 260 } 261 262 gh = NULL; 263 ip = NULL; 264 265 /* BPF writes need to be handled specially. */ 266 if (dst->sa_family == AF_UNSPEC) { 267 bcopy(dst->sa_data, &af, sizeof(af)); 268 dst->sa_family = af; 269 } 270 271 if (ifp->if_bpf) { 272 af = dst->sa_family; 273 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 274 } 275 276 m->m_flags &= ~(M_BCAST|M_MCAST); 277 278 if (sc->g_proto == IPPROTO_MOBILE) { 279 if (dst->sa_family == AF_INET) { 280 struct mbuf *m0; 281 int msiz; 282 283 ip = mtod(m, struct ip *); 284 285 /* 286 * RFC2004 specifies that fragmented diagrams shouldn't 287 * be encapsulated. 288 */ 289 if ((ip->ip_off & IP_MF) != 0) { 290 _IF_DROP(&ifp->if_snd); 291 m_freem(m); 292 error = EINVAL; /* is there better errno? */ 293 goto end; 294 } 295 memset(&mob_h, 0, MOB_H_SIZ_L); 296 mob_h.proto = (ip->ip_p) << 8; 297 mob_h.odst = ip->ip_dst.s_addr; 298 ip->ip_dst.s_addr = sc->g_dst.s_addr; 299 300 /* 301 * If the packet comes from our host, we only change 302 * the destination address in the IP header. 303 * Else we also need to save and change the source 304 */ 305 if (in_hosteq(ip->ip_src, sc->g_src)) { 306 msiz = MOB_H_SIZ_S; 307 } else { 308 mob_h.proto |= MOB_H_SBIT; 309 mob_h.osrc = ip->ip_src.s_addr; 310 ip->ip_src.s_addr = sc->g_src.s_addr; 311 msiz = MOB_H_SIZ_L; 312 } 313 mob_h.proto = htons(mob_h.proto); 314 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 315 316 if ((m->m_data - msiz) < m->m_pktdat) { 317 /* need new mbuf */ 318 MGETHDR(m0, M_DONTWAIT, MT_DATA); 319 if (m0 == NULL) { 320 _IF_DROP(&ifp->if_snd); 321 m_freem(m); 322 error = ENOBUFS; 323 goto end; 324 } 325 m0->m_next = m; 326 m->m_data += sizeof(struct ip); 327 m->m_len -= sizeof(struct ip); 328 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 329 m0->m_len = msiz + sizeof(struct ip); 330 m0->m_data += max_linkhdr; 331 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 332 sizeof(struct ip)); 333 m = m0; 334 } else { /* we have some space left in the old one */ 335 m->m_data -= msiz; 336 m->m_len += msiz; 337 m->m_pkthdr.len += msiz; 338 bcopy(ip, mtod(m, caddr_t), 339 sizeof(struct ip)); 340 } 341 ip = mtod(m, struct ip *); 342 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 343 ip->ip_len = ntohs(ip->ip_len) + msiz; 344 } else { /* AF_INET */ 345 _IF_DROP(&ifp->if_snd); 346 m_freem(m); 347 error = EINVAL; 348 goto end; 349 } 350 } else if (sc->g_proto == IPPROTO_GRE) { 351 switch (dst->sa_family) { 352 case AF_INET: 353 ip = mtod(m, struct ip *); 354 ip_tos = ip->ip_tos; 355 ip_id = ip->ip_id; 356 etype = ETHERTYPE_IP; 357 break; 358#ifdef INET6 359 case AF_INET6: 360 ip_id = ip_newid(); 361 etype = ETHERTYPE_IPV6; 362 break; 363#endif 364#ifdef NETATALK 365 case AF_APPLETALK: 366 etype = ETHERTYPE_ATALK; 367 break; 368#endif 369 default: 370 _IF_DROP(&ifp->if_snd); 371 m_freem(m); 372 error = EAFNOSUPPORT; 373 goto end; 374 } 375 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 376 } else { 377 _IF_DROP(&ifp->if_snd); 378 m_freem(m); 379 error = EINVAL; 380 goto end; 381 } 382 383 if (m == NULL) { /* mbuf allocation failed */ 384 _IF_DROP(&ifp->if_snd); 385 error = ENOBUFS; 386 goto end; 387 } 388 389 gh = mtod(m, struct greip *); 390 if (sc->g_proto == IPPROTO_GRE) { 391 /* we don't have any GRE flags for now */ 392 memset((void *)gh, 0, sizeof(struct greip)); 393 gh->gi_ptype = htons(etype); 394 } 395 396 gh->gi_pr = sc->g_proto; 397 if (sc->g_proto != IPPROTO_MOBILE) { 398 gh->gi_src = sc->g_src; 399 gh->gi_dst = sc->g_dst; 400 ((struct ip*)gh)->ip_v = IPPROTO_IPV4; 401 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 402 ((struct ip*)gh)->ip_ttl = GRE_TTL; 403 ((struct ip*)gh)->ip_tos = ip_tos; 404 ((struct ip*)gh)->ip_id = ip_id; 405 gh->gi_len = m->m_pkthdr.len; 406 } 407 408 ifp->if_opackets++; 409 ifp->if_obytes += m->m_pkthdr.len; 410 /* 411 * Send it off and with IP_FORWARD flag to prevent it from 412 * overwriting the ip_id again. ip_id is already set to the 413 * ip_id of the encapsulated packet. 414 */ 415 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 416 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 417 end: 418 sc->called = 0; 419 if (error) 420 ifp->if_oerrors++; 421 return (error); 422} 423 424static int 425gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 426{ 427 struct ifreq *ifr = (struct ifreq *)data; 428 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 429 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 430 struct gre_softc *sc = ifp->if_softc; 431 int s; 432 struct sockaddr_in si; 433 struct sockaddr *sa = NULL; 434 int error; 435 struct sockaddr_in sp, sm, dp, dm; 436 437 error = 0; 438 439 s = splnet(); 440 switch (cmd) { 441 case SIOCSIFADDR: 442 ifp->if_flags |= IFF_UP; 443 break; 444 case SIOCSIFDSTADDR: 445 break; 446 case SIOCSIFFLAGS: 447 if ((error = suser(curthread)) != 0) 448 break; 449 if ((ifr->ifr_flags & IFF_LINK0) != 0) 450 sc->g_proto = IPPROTO_GRE; 451 else 452 sc->g_proto = IPPROTO_MOBILE; 453 if ((ifr->ifr_flags & IFF_LINK2) != 0) 454 sc->wccp_ver = WCCP_V2; 455 else 456 sc->wccp_ver = WCCP_V1; 457 goto recompute; 458 case SIOCSIFMTU: 459 if ((error = suser(curthread)) != 0) 460 break; 461 if (ifr->ifr_mtu < 576) { 462 error = EINVAL; 463 break; 464 } 465 ifp->if_mtu = ifr->ifr_mtu; 466 break; 467 case SIOCGIFMTU: 468 ifr->ifr_mtu = GRE2IFP(sc)->if_mtu; 469 break; 470 case SIOCADDMULTI: 471 case SIOCDELMULTI: 472 if ((error = suser(curthread)) != 0) 473 break; 474 if (ifr == 0) { 475 error = EAFNOSUPPORT; 476 break; 477 } 478 switch (ifr->ifr_addr.sa_family) { 479#ifdef INET 480 case AF_INET: 481 break; 482#endif 483#ifdef INET6 484 case AF_INET6: 485 break; 486#endif 487 default: 488 error = EAFNOSUPPORT; 489 break; 490 } 491 break; 492 case GRESPROTO: 493 if ((error = suser(curthread)) != 0) 494 break; 495 sc->g_proto = ifr->ifr_flags; 496 switch (sc->g_proto) { 497 case IPPROTO_GRE: 498 ifp->if_flags |= IFF_LINK0; 499 break; 500 case IPPROTO_MOBILE: 501 ifp->if_flags &= ~IFF_LINK0; 502 break; 503 default: 504 error = EPROTONOSUPPORT; 505 break; 506 } 507 goto recompute; 508 case GREGPROTO: 509 ifr->ifr_flags = sc->g_proto; 510 break; 511 case GRESADDRS: 512 case GRESADDRD: 513 if ((error = suser(curthread)) != 0) 514 break; 515 /* 516 * set tunnel endpoints, compute a less specific route 517 * to the remote end and mark if as up 518 */ 519 sa = &ifr->ifr_addr; 520 if (cmd == GRESADDRS) 521 sc->g_src = (satosin(sa))->sin_addr; 522 if (cmd == GRESADDRD) 523 sc->g_dst = (satosin(sa))->sin_addr; 524 recompute: 525#ifdef INET 526 if (sc->encap != NULL) { 527 encap_detach(sc->encap); 528 sc->encap = NULL; 529 } 530#endif 531 if ((sc->g_src.s_addr != INADDR_ANY) && 532 (sc->g_dst.s_addr != INADDR_ANY)) { 533 bzero(&sp, sizeof(sp)); 534 bzero(&sm, sizeof(sm)); 535 bzero(&dp, sizeof(dp)); 536 bzero(&dm, sizeof(dm)); 537 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 538 sizeof(struct sockaddr_in); 539 sp.sin_family = sm.sin_family = dp.sin_family = 540 dm.sin_family = AF_INET; 541 sp.sin_addr = sc->g_src; 542 dp.sin_addr = sc->g_dst; 543 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 544 INADDR_BROADCAST; 545#ifdef INET 546 sc->encap = encap_attach(AF_INET, sc->g_proto, 547 sintosa(&sp), sintosa(&sm), sintosa(&dp), 548 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 549 &in_gre_protosw : &in_mobile_protosw, sc); 550 if (sc->encap == NULL) 551 printf("%s: unable to attach encap\n", 552 if_name(GRE2IFP(sc))); 553#endif 554 if (sc->route.ro_rt != 0) /* free old route */ 555 RTFREE(sc->route.ro_rt); 556 if (gre_compute_route(sc) == 0) 557 ifp->if_drv_flags |= IFF_DRV_RUNNING; 558 else 559 ifp->if_drv_flags &= ~IFF_DRV_RUNNING; 560 } 561 break; 562 case GREGADDRS: 563 memset(&si, 0, sizeof(si)); 564 si.sin_family = AF_INET; 565 si.sin_len = sizeof(struct sockaddr_in); 566 si.sin_addr.s_addr = sc->g_src.s_addr; 567 sa = sintosa(&si); 568 ifr->ifr_addr = *sa; 569 break; 570 case GREGADDRD: 571 memset(&si, 0, sizeof(si)); 572 si.sin_family = AF_INET; 573 si.sin_len = sizeof(struct sockaddr_in); 574 si.sin_addr.s_addr = sc->g_dst.s_addr; 575 sa = sintosa(&si); 576 ifr->ifr_addr = *sa; 577 break; 578 case SIOCSIFPHYADDR: 579 if ((error = suser(curthread)) != 0) 580 break; 581 if (aifr->ifra_addr.sin_family != AF_INET || 582 aifr->ifra_dstaddr.sin_family != AF_INET) { 583 error = EAFNOSUPPORT; 584 break; 585 } 586 if (aifr->ifra_addr.sin_len != sizeof(si) || 587 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 588 error = EINVAL; 589 break; 590 } 591 sc->g_src = aifr->ifra_addr.sin_addr; 592 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 593 goto recompute; 594 case SIOCSLIFPHYADDR: 595 if ((error = suser(curthread)) != 0) 596 break; 597 if (lifr->addr.ss_family != AF_INET || 598 lifr->dstaddr.ss_family != AF_INET) { 599 error = EAFNOSUPPORT; 600 break; 601 } 602 if (lifr->addr.ss_len != sizeof(si) || 603 lifr->dstaddr.ss_len != sizeof(si)) { 604 error = EINVAL; 605 break; 606 } 607 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 608 sc->g_dst = 609 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 610 goto recompute; 611 case SIOCDIFPHYADDR: 612 if ((error = suser(curthread)) != 0) 613 break; 614 sc->g_src.s_addr = INADDR_ANY; 615 sc->g_dst.s_addr = INADDR_ANY; 616 goto recompute; 617 case SIOCGLIFPHYADDR: 618 if (sc->g_src.s_addr == INADDR_ANY || 619 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_src.s_addr; 627 memcpy(&lifr->addr, &si, sizeof(si)); 628 si.sin_addr.s_addr = sc->g_dst.s_addr; 629 memcpy(&lifr->dstaddr, &si, sizeof(si)); 630 break; 631 case SIOCGIFPSRCADDR: 632#ifdef INET6 633 case SIOCGIFPSRCADDR_IN6: 634#endif 635 if (sc->g_src.s_addr == INADDR_ANY) { 636 error = EADDRNOTAVAIL; 637 break; 638 } 639 memset(&si, 0, sizeof(si)); 640 si.sin_family = AF_INET; 641 si.sin_len = sizeof(struct sockaddr_in); 642 si.sin_addr.s_addr = sc->g_src.s_addr; 643 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 644 break; 645 case SIOCGIFPDSTADDR: 646#ifdef INET6 647 case SIOCGIFPDSTADDR_IN6: 648#endif 649 if (sc->g_dst.s_addr == INADDR_ANY) { 650 error = EADDRNOTAVAIL; 651 break; 652 } 653 memset(&si, 0, sizeof(si)); 654 si.sin_family = AF_INET; 655 si.sin_len = sizeof(struct sockaddr_in); 656 si.sin_addr.s_addr = sc->g_dst.s_addr; 657 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 658 break; 659 default: 660 error = EINVAL; 661 break; 662 } 663 664 splx(s); 665 return (error); 666} 667 668/* 669 * computes a route to our destination that is not the one 670 * which would be taken by ip_output(), as this one will loop back to 671 * us. If the interface is p2p as a--->b, then a routing entry exists 672 * If we now send a packet to b (e.g. ping b), this will come down here 673 * gets src=a, dst=b tacked on and would from ip_output() sent back to 674 * if_gre. 675 * Goal here is to compute a route to b that is less specific than 676 * a-->b. We know that this one exists as in normal operation we have 677 * at least a default route which matches. 678 */ 679static int 680gre_compute_route(struct gre_softc *sc) 681{ 682 struct route *ro; 683 u_int32_t a, b, c; 684 685 ro = &sc->route; 686 687 memset(ro, 0, sizeof(struct route)); 688 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 689 ro->ro_dst.sa_family = AF_INET; 690 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 691 692 /* 693 * toggle last bit, so our interface is not found, but a less 694 * specific route. I'd rather like to specify a shorter mask, 695 * but this is not possible. Should work though. XXX 696 * there is a simpler way ... 697 */ 698 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) { 699 a = ntohl(sc->g_dst.s_addr); 700 b = a & 0x01; 701 c = a & 0xfffffffe; 702 b = b ^ 0x01; 703 a = b | c; 704 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 705 = htonl(a); 706 } 707 708#ifdef DIAGNOSTIC 709 printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)), 710 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 711#endif 712 713 rtalloc(ro); 714 715 /* 716 * check if this returned a route at all and this route is no 717 * recursion to ourself 718 */ 719 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 720#ifdef DIAGNOSTIC 721 if (ro->ro_rt == NULL) 722 printf(" - no route found!\n"); 723 else 724 printf(" - route loops back to ourself!\n"); 725#endif 726 return EADDRNOTAVAIL; 727 } 728 729 /* 730 * now change it back - else ip_output will just drop 731 * the route and search one to this interface ... 732 */ 733 if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) 734 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 735 736#ifdef DIAGNOSTIC 737 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 738 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 739 printf("\n"); 740#endif 741 742 return 0; 743} 744 745/* 746 * do a checksum of a buffer - much like in_cksum, which operates on 747 * mbufs. 748 */ 749u_int16_t 750gre_in_cksum(u_int16_t *p, u_int len) 751{ 752 u_int32_t sum = 0; 753 int nwords = len >> 1; 754 755 while (nwords-- != 0) 756 sum += *p++; 757 758 if (len & 1) { 759 union { 760 u_short w; 761 u_char c[2]; 762 } u; 763 u.c[0] = *(u_char *)p; 764 u.c[1] = 0; 765 sum += u.w; 766 } 767 768 /* end-around-carry */ 769 sum = (sum >> 16) + (sum & 0xffff); 770 sum += (sum >> 16); 771 return (~sum); 772} 773 774static int 775gremodevent(module_t mod, int type, void *data) 776{ 777 778 switch (type) { 779 case MOD_LOAD: 780 greattach(); 781 break; 782 case MOD_UNLOAD: 783 if_clone_detach(&gre_cloner); 784 mtx_destroy(&gre_mtx); 785 break; 786 default: 787 return EOPNOTSUPP; 788 } 789 return 0; 790} 791 792static moduledata_t gre_mod = { 793 "if_gre", 794 gremodevent, 795 0 796}; 797 798DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 799MODULE_VERSION(if_gre, 1); 800