1 /* $NetBSD: if_gre.c,v 1.42 2002/08/14 00:23:27 itojun Exp $ */ 2 /* $FreeBSD: src/sys/net/if_gre.c,v 1.9.2.3 2003/01/23 21:06:44 sam Exp $ */ 3 /* $DragonFly: src/sys/net/gre/if_gre.c,v 1.22 2008/10/27 02:56:30 sephe Exp $ */ 4 5 /* 6 * Copyright (c) 1998 The NetBSD Foundation, Inc. 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to The NetBSD Foundation 10 * by Heiko W.Rupp <hwr@pilhuhn.de> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 /* 42 * Encapsulate L3 protocols into IP 43 * See RFC 1701 and 1702 for more details. 44 * If_gre is compatible with Cisco GRE tunnels, so you can 45 * have a NetBSD box as the other end of a tunnel interface of a Cisco 46 * router. See gre(4) for more details. 47 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 48 */ 49 50 #include "opt_atalk.h" 51 #include "opt_inet.h" 52 #include "opt_ns.h" 53 54 #include <sys/param.h> 55 #include <sys/kernel.h> 56 #include <sys/bus.h> 57 #include <sys/malloc.h> 58 #include <sys/mbuf.h> 59 #include <sys/proc.h> 60 #include <sys/priv.h> 61 #include <sys/protosw.h> 62 #include <sys/socket.h> 63 #include <sys/sockio.h> 64 #include <sys/sysctl.h> 65 #include <sys/systm.h> 66 #include <sys/thread2.h> 67 68 #include <net/ethernet.h> 69 #include <net/if.h> 70 #include <net/if_types.h> 71 #include <net/route.h> 72 #include <net/if_clone.h> 73 74 #ifdef INET 75 #include <netinet/in.h> 76 #include <netinet/in_systm.h> 77 #include <netinet/in_var.h> 78 #include <netinet/ip.h> 79 #include <netinet/ip_gre.h> 80 #include <netinet/ip_var.h> 81 #include <netinet/ip_encap.h> 82 #else 83 #error "Huh? if_gre without inet?" 84 #endif 85 86 #include <net/bpf.h> 87 88 #include <net/net_osdep.h> 89 #include "if_gre.h" 90 91 /* 92 * It is not easy to calculate the right value for a GRE MTU. 93 * We leave this task to the admin and use the same default that 94 * other vendors use. 95 */ 96 #define GREMTU 1476 97 98 #define GRENAME "gre" 99 100 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 101 102 struct gre_softc_head gre_softc_list; 103 104 static int gre_clone_create(struct if_clone *, int); 105 static void gre_clone_destroy(struct ifnet *); 106 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *); 107 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 108 struct rtentry *rt); 109 110 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", 111 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 112 113 static int gre_compute_route(struct gre_softc *sc); 114 115 static void greattach(void); 116 117 #ifdef INET 118 extern struct domain inetdomain; 119 static const struct protosw in_gre_protosw = 120 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 121 gre_input, rip_output, rip_ctlinput, rip_ctloutput, 122 cpu0_soport, cpu0_ctlport, 123 0, 0, 0, 0, 124 &rip_usrreqs 125 }; 126 static const struct protosw in_mobile_protosw = 127 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 128 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput, 129 cpu0_soport, cpu0_ctlport, 130 0, 0, 0, 0, 131 &rip_usrreqs 132 }; 133 #endif 134 135 SYSCTL_DECL(_net_link); 136 SYSCTL_NODE(_net_link, IFT_OTHER, 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 149 static int max_gre_nesting = MAX_GRE_NEST; 150 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 151 &max_gre_nesting, 0, "Max nested tunnels"); 152 153 /* ARGSUSED */ 154 static void 155 greattach(void) 156 { 157 158 LIST_INIT(&gre_softc_list); 159 if_clone_attach(&gre_cloner); 160 } 161 162 static int 163 gre_clone_create(struct if_clone *ifc, int unit) 164 { 165 struct gre_softc *sc; 166 167 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 168 memset(sc, 0, sizeof(struct gre_softc)); 169 170 sc->sc_if.if_softc = sc; 171 if_initname(&(sc->sc_if), GRENAME, unit); 172 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 173 sc->sc_if.if_type = IFT_OTHER; 174 sc->sc_if.if_addrlen = 0; 175 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 176 sc->sc_if.if_mtu = GREMTU; 177 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 178 sc->sc_if.if_output = gre_output; 179 sc->sc_if.if_ioctl = gre_ioctl; 180 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 181 sc->g_proto = IPPROTO_GRE; 182 sc->sc_if.if_flags |= IFF_LINK0; 183 sc->encap = NULL; 184 sc->called = 0; 185 if_attach(&sc->sc_if, NULL); 186 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 187 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 188 return (0); 189 } 190 191 static void 192 gre_clone_destroy(struct ifnet *ifp) 193 { 194 struct gre_softc *sc = ifp->if_softc; 195 196 #ifdef INET 197 if (sc->encap != NULL) 198 encap_detach(sc->encap); 199 #endif 200 LIST_REMOVE(sc, sc_list); 201 bpfdetach(ifp); 202 if_detach(ifp); 203 204 kfree(sc, M_GRE); 205 } 206 207 /* 208 * The output routine. Takes a packet and encapsulates it in the protocol 209 * given by sc->g_proto. See also RFC 1701 and RFC 2004 210 */ 211 static int 212 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 213 struct rtentry *rt) 214 { 215 int error = 0; 216 struct gre_softc *sc = ifp->if_softc; 217 struct greip *gh; 218 struct ip *ip; 219 u_char osrc; 220 u_short etype = 0; 221 struct mobile_h mob_h; 222 223 /* 224 * gre may cause infinite recursion calls when misconfigured. 225 * We'll prevent this by introducing upper limit. 226 */ 227 if (++(sc->called) > max_gre_nesting) { 228 kprintf("%s: gre_output: recursively called too many " 229 "times(%d)\n", if_name(&sc->sc_if), sc->called); 230 m_freem(m); 231 error = EIO; /* is there better errno? */ 232 goto end; 233 } 234 235 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 236 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 237 m_freem(m); 238 error = ENETDOWN; 239 goto end; 240 } 241 242 gh = NULL; 243 ip = NULL; 244 osrc = 0; 245 246 if (ifp->if_bpf) { 247 uint32_t af = dst->sa_family; 248 249 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 250 } 251 252 m->m_flags &= ~(M_BCAST|M_MCAST); 253 254 if (sc->g_proto == IPPROTO_MOBILE) { 255 if (dst->sa_family == AF_INET) { 256 struct mbuf *m0; 257 int msiz; 258 259 ip = mtod(m, struct ip *); 260 261 /* 262 * RFC2004 specifies that fragmented datagrams shouldn't 263 * be encapsulated. 264 */ 265 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 266 IF_DROP(&ifp->if_snd); 267 m_freem(m); 268 error = EINVAL; /* is there better errno? */ 269 goto end; 270 } 271 memset(&mob_h, 0, MOB_H_SIZ_L); 272 mob_h.proto = (ip->ip_p) << 8; 273 mob_h.odst = ip->ip_dst.s_addr; 274 ip->ip_dst.s_addr = sc->g_dst.s_addr; 275 276 /* 277 * If the packet comes from our host, we only change 278 * the destination address in the IP header. 279 * Else we also need to save and change the source 280 */ 281 if (in_hosteq(ip->ip_src, sc->g_src)) { 282 msiz = MOB_H_SIZ_S; 283 } else { 284 mob_h.proto |= MOB_H_SBIT; 285 mob_h.osrc = ip->ip_src.s_addr; 286 ip->ip_src.s_addr = sc->g_src.s_addr; 287 msiz = MOB_H_SIZ_L; 288 } 289 mob_h.proto = htons(mob_h.proto); 290 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 291 292 if ((m->m_data - msiz) < m->m_pktdat) { 293 /* need new mbuf */ 294 MGETHDR(m0, MB_DONTWAIT, MT_HEADER); 295 if (m0 == NULL) { 296 IF_DROP(&ifp->if_snd); 297 m_freem(m); 298 error = ENOBUFS; 299 goto end; 300 } 301 m0->m_next = m; 302 m->m_data += sizeof(struct ip); 303 m->m_len -= sizeof(struct ip); 304 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 305 m0->m_len = msiz + sizeof(struct ip); 306 m0->m_data += max_linkhdr; 307 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 308 sizeof(struct ip)); 309 m = m0; 310 } else { /* we have some space left in the old one */ 311 m->m_data -= msiz; 312 m->m_len += msiz; 313 m->m_pkthdr.len += msiz; 314 bcopy(ip, mtod(m, caddr_t), 315 sizeof(struct ip)); 316 } 317 ip = mtod(m, struct ip *); 318 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 319 ip->ip_len = ntohs(ip->ip_len) + msiz; 320 } else { /* AF_INET */ 321 IF_DROP(&ifp->if_snd); 322 m_freem(m); 323 error = EINVAL; 324 goto end; 325 } 326 } else if (sc->g_proto == IPPROTO_GRE) { 327 switch (dst->sa_family) { 328 case AF_INET: 329 ip = mtod(m, struct ip *); 330 etype = ETHERTYPE_IP; 331 break; 332 #ifdef NETATALK 333 case AF_APPLETALK: 334 etype = ETHERTYPE_ATALK; 335 break; 336 #endif 337 #ifdef NS 338 case AF_NS: 339 etype = ETHERTYPE_NS; 340 break; 341 #endif 342 default: 343 IF_DROP(&ifp->if_snd); 344 m_freem(m); 345 error = EAFNOSUPPORT; 346 goto end; 347 } 348 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 349 } else { 350 IF_DROP(&ifp->if_snd); 351 m_freem(m); 352 error = EINVAL; 353 goto end; 354 } 355 356 if (m == NULL) { /* impossible */ 357 IF_DROP(&ifp->if_snd); 358 error = ENOBUFS; 359 goto end; 360 } 361 362 gh = mtod(m, struct greip *); 363 if (sc->g_proto == IPPROTO_GRE) { 364 /* we don't have any GRE flags for now */ 365 366 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 367 gh->gi_ptype = htons(etype); 368 } 369 370 gh->gi_pr = sc->g_proto; 371 if (sc->g_proto != IPPROTO_MOBILE) { 372 gh->gi_src = sc->g_src; 373 gh->gi_dst = sc->g_dst; 374 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 375 ((struct ip*)gh)->ip_ttl = GRE_TTL; 376 ((struct ip*)gh)->ip_tos = ip->ip_tos; 377 ((struct ip*)gh)->ip_id = ip->ip_id; 378 gh->gi_len = m->m_pkthdr.len; 379 } 380 381 ifp->if_opackets++; 382 ifp->if_obytes += m->m_pkthdr.len; 383 /* send it off */ 384 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 385 end: 386 sc->called = 0; 387 if (error) 388 ifp->if_oerrors++; 389 return (error); 390 } 391 392 static int 393 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 394 struct rtentry *rt) 395 { 396 int error; 397 398 ifnet_serialize_tx(ifp); 399 error = gre_output_serialized(ifp, m, dst, rt); 400 ifnet_deserialize_tx(ifp); 401 402 return error; 403 } 404 405 static int 406 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 407 { 408 struct ifreq *ifr = (struct ifreq *)data; 409 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 410 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 411 struct gre_softc *sc = ifp->if_softc; 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 crit_enter(); 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 = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 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 goto recompute; 434 case SIOCSIFMTU: 435 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 436 break; 437 if (ifr->ifr_mtu < 576) { 438 error = EINVAL; 439 break; 440 } 441 ifp->if_mtu = ifr->ifr_mtu; 442 break; 443 case SIOCGIFMTU: 444 ifr->ifr_mtu = sc->sc_if.if_mtu; 445 break; 446 case SIOCADDMULTI: 447 case SIOCDELMULTI: 448 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 449 break; 450 if (ifr == 0) { 451 error = EAFNOSUPPORT; 452 break; 453 } 454 switch (ifr->ifr_addr.sa_family) { 455 #ifdef INET 456 case AF_INET: 457 break; 458 #endif 459 default: 460 error = EAFNOSUPPORT; 461 break; 462 } 463 break; 464 case GRESPROTO: 465 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 466 break; 467 sc->g_proto = ifr->ifr_flags; 468 switch (sc->g_proto) { 469 case IPPROTO_GRE: 470 ifp->if_flags |= IFF_LINK0; 471 break; 472 case IPPROTO_MOBILE: 473 ifp->if_flags &= ~IFF_LINK0; 474 break; 475 default: 476 error = EPROTONOSUPPORT; 477 break; 478 } 479 goto recompute; 480 case GREGPROTO: 481 ifr->ifr_flags = sc->g_proto; 482 break; 483 case GRESADDRS: 484 case GRESADDRD: 485 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 486 break; 487 /* 488 * set tunnel endpoints, compute a less specific route 489 * to the remote end and mark if as up 490 */ 491 sa = &ifr->ifr_addr; 492 if (cmd == GRESADDRS) 493 sc->g_src = (satosin(sa))->sin_addr; 494 if (cmd == GRESADDRD) 495 sc->g_dst = (satosin(sa))->sin_addr; 496 recompute: 497 #ifdef INET 498 if (sc->encap != NULL) { 499 encap_detach(sc->encap); 500 sc->encap = NULL; 501 } 502 #endif 503 if ((sc->g_src.s_addr != INADDR_ANY) && 504 (sc->g_dst.s_addr != INADDR_ANY)) { 505 bzero(&sp, sizeof(sp)); 506 bzero(&sm, sizeof(sm)); 507 bzero(&dp, sizeof(dp)); 508 bzero(&dm, sizeof(dm)); 509 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 510 sizeof(struct sockaddr_in); 511 sp.sin_family = sm.sin_family = dp.sin_family = 512 dm.sin_family = AF_INET; 513 sp.sin_addr = sc->g_src; 514 dp.sin_addr = sc->g_dst; 515 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 516 INADDR_BROADCAST; 517 #ifdef INET 518 sc->encap = encap_attach(AF_INET, sc->g_proto, 519 sintosa(&sp), sintosa(&sm), sintosa(&dp), 520 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 521 &in_gre_protosw : &in_mobile_protosw, sc); 522 if (sc->encap == NULL) 523 kprintf("%s: unable to attach encap\n", 524 if_name(&sc->sc_if)); 525 #endif 526 if (sc->route.ro_rt != 0) /* free old route */ 527 RTFREE(sc->route.ro_rt); 528 if (gre_compute_route(sc) == 0) 529 ifp->if_flags |= IFF_RUNNING; 530 else 531 ifp->if_flags &= ~IFF_RUNNING; 532 } 533 break; 534 case GREGADDRS: 535 memset(&si, 0, sizeof(si)); 536 si.sin_family = AF_INET; 537 si.sin_len = sizeof(struct sockaddr_in); 538 si.sin_addr.s_addr = sc->g_src.s_addr; 539 sa = sintosa(&si); 540 ifr->ifr_addr = *sa; 541 break; 542 case GREGADDRD: 543 memset(&si, 0, sizeof(si)); 544 si.sin_family = AF_INET; 545 si.sin_len = sizeof(struct sockaddr_in); 546 si.sin_addr.s_addr = sc->g_dst.s_addr; 547 sa = sintosa(&si); 548 ifr->ifr_addr = *sa; 549 break; 550 case SIOCSIFPHYADDR: 551 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 552 break; 553 if (aifr->ifra_addr.sin_family != AF_INET || 554 aifr->ifra_dstaddr.sin_family != AF_INET) { 555 error = EAFNOSUPPORT; 556 break; 557 } 558 if (aifr->ifra_addr.sin_len != sizeof(si) || 559 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 560 error = EINVAL; 561 break; 562 } 563 sc->g_src = aifr->ifra_addr.sin_addr; 564 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 565 goto recompute; 566 case SIOCSLIFPHYADDR: 567 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 568 break; 569 if (lifr->addr.ss_family != AF_INET || 570 lifr->dstaddr.ss_family != AF_INET) { 571 error = EAFNOSUPPORT; 572 break; 573 } 574 if (lifr->addr.ss_len != sizeof(si) || 575 lifr->dstaddr.ss_len != sizeof(si)) { 576 error = EINVAL; 577 break; 578 } 579 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 580 sc->g_dst = 581 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 582 goto recompute; 583 case SIOCDIFPHYADDR: 584 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 585 break; 586 sc->g_src.s_addr = INADDR_ANY; 587 sc->g_dst.s_addr = INADDR_ANY; 588 goto recompute; 589 case SIOCGLIFPHYADDR: 590 if (sc->g_src.s_addr == INADDR_ANY || 591 sc->g_dst.s_addr == INADDR_ANY) { 592 error = EADDRNOTAVAIL; 593 break; 594 } 595 memset(&si, 0, sizeof(si)); 596 si.sin_family = AF_INET; 597 si.sin_len = sizeof(struct sockaddr_in); 598 si.sin_addr.s_addr = sc->g_src.s_addr; 599 memcpy(&lifr->addr, &si, sizeof(si)); 600 si.sin_addr.s_addr = sc->g_dst.s_addr; 601 memcpy(&lifr->dstaddr, &si, sizeof(si)); 602 break; 603 case SIOCGIFPSRCADDR: 604 if (sc->g_src.s_addr == INADDR_ANY) { 605 error = EADDRNOTAVAIL; 606 break; 607 } 608 memset(&si, 0, sizeof(si)); 609 si.sin_family = AF_INET; 610 si.sin_len = sizeof(struct sockaddr_in); 611 si.sin_addr.s_addr = sc->g_src.s_addr; 612 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 613 break; 614 case SIOCGIFPDSTADDR: 615 if (sc->g_dst.s_addr == INADDR_ANY) { 616 error = EADDRNOTAVAIL; 617 break; 618 } 619 memset(&si, 0, sizeof(si)); 620 si.sin_family = AF_INET; 621 si.sin_len = sizeof(struct sockaddr_in); 622 si.sin_addr.s_addr = sc->g_dst.s_addr; 623 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 624 break; 625 default: 626 error = EINVAL; 627 break; 628 } 629 630 crit_exit(); 631 return (error); 632 } 633 634 /* 635 * computes a route to our destination that is not the one 636 * which would be taken by ip_output(), as this one will loop back to 637 * us. If the interface is p2p as a--->b, then a routing entry exists 638 * If we now send a packet to b (e.g. ping b), this will come down here 639 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 640 * if_gre. 641 * Goal here is to compute a route to b that is less specific than 642 * a-->b. We know that this one exists as in normal operation we have 643 * at least a default route which matches. 644 */ 645 static int 646 gre_compute_route(struct gre_softc *sc) 647 { 648 struct route *ro; 649 u_int32_t a, b, c; 650 651 ro = &sc->route; 652 653 memset(ro, 0, sizeof(struct route)); 654 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 655 ro->ro_dst.sa_family = AF_INET; 656 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 657 658 /* 659 * toggle last bit, so our interface is not found, but a less 660 * specific route. I'd rather like to specify a shorter mask, 661 * but this is not possible. Should work though. XXX 662 * there is a simpler way ... 663 */ 664 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 665 a = ntohl(sc->g_dst.s_addr); 666 b = a & 0x01; 667 c = a & 0xfffffffe; 668 b = b ^ 0x01; 669 a = b | c; 670 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 671 = htonl(a); 672 } 673 674 #ifdef DIAGNOSTIC 675 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 676 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 677 #endif 678 679 rtalloc(ro); 680 681 /* 682 * check if this returned a route at all and this route is no 683 * recursion to ourself 684 */ 685 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 686 #ifdef DIAGNOSTIC 687 if (ro->ro_rt == NULL) 688 kprintf(" - no route found!\n"); 689 else 690 kprintf(" - route loops back to ourself!\n"); 691 #endif 692 return EADDRNOTAVAIL; 693 } 694 695 /* 696 * now change it back - else ip_output will just drop 697 * the route and search one to this interface ... 698 */ 699 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 700 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 701 702 #ifdef DIAGNOSTIC 703 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 704 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 705 kprintf("\n"); 706 #endif 707 708 return 0; 709 } 710 711 /* 712 * do a checksum of a buffer - much like in_cksum, which operates on 713 * mbufs. 714 */ 715 u_short 716 gre_in_cksum(u_short *p, u_int len) 717 { 718 u_int sum = 0; 719 int nwords = len >> 1; 720 721 while (nwords-- != 0) 722 sum += *p++; 723 724 if (len & 1) { 725 union { 726 u_short w; 727 u_char c[2]; 728 } u; 729 u.c[0] = *(u_char *)p; 730 u.c[1] = 0; 731 sum += u.w; 732 } 733 734 /* end-around-carry */ 735 sum = (sum >> 16) + (sum & 0xffff); 736 sum += (sum >> 16); 737 return (~sum); 738 } 739 740 static int 741 gremodevent(module_t mod, int type, void *data) 742 { 743 744 switch (type) { 745 case MOD_LOAD: 746 greattach(); 747 break; 748 case MOD_UNLOAD: 749 if_clone_detach(&gre_cloner); 750 751 while (!LIST_EMPTY(&gre_softc_list)) 752 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 753 754 break; 755 } 756 return 0; 757 } 758 759 static moduledata_t gre_mod = { 760 "if_gre", 761 gremodevent, 762 0 763 }; 764 765 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 766 MODULE_VERSION(if_gre, 1); 767