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 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_inet.h" 50 51 #include <sys/param.h> 52 #include <sys/kernel.h> 53 #include <sys/bus.h> 54 #include <sys/malloc.h> 55 #include <sys/mbuf.h> 56 #include <sys/proc.h> 57 #include <sys/priv.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 #include <sys/thread2.h> 64 65 #include <net/ethernet.h> 66 #include <net/if.h> 67 #include <net/if_types.h> 68 #include <net/route.h> 69 #include <net/if_clone.h> 70 71 #ifdef INET 72 #include <netinet/in.h> 73 #include <netinet/in_systm.h> 74 #include <netinet/in_var.h> 75 #include <netinet/ip.h> 76 #include <netinet/ip_gre.h> 77 #include <netinet/ip_var.h> 78 #include <netinet/ip_encap.h> 79 #else 80 #error "Huh? if_gre without inet?" 81 #endif 82 83 #include <net/bpf.h> 84 85 #include <net/net_osdep.h> 86 #include "if_gre.h" 87 88 /* 89 * It is not easy to calculate the right value for a GRE MTU. 90 * We leave this task to the admin and use the same default that 91 * other vendors use. 92 */ 93 #define GREMTU 1476 94 95 #define GRENAME "gre" 96 97 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 98 99 struct gre_softc_head gre_softc_list; 100 101 static int gre_clone_create(struct if_clone *, int, caddr_t); 102 static int gre_clone_destroy(struct ifnet *); 103 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *); 104 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 105 struct rtentry *rt); 106 107 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", 108 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 109 110 static int gre_compute_route(struct gre_softc *sc); 111 112 static void greattach(void); 113 114 #ifdef INET 115 116 extern struct domain inetdomain; 117 118 static const struct protosw in_gre_protosw = 119 { 120 .pr_type = SOCK_RAW, 121 .pr_domain = &inetdomain, 122 .pr_protocol = IPPROTO_GRE, 123 .pr_flags = PR_ATOMIC|PR_ADDR, 124 125 .pr_input = gre_input, 126 .pr_output = rip_output, 127 .pr_ctlinput = rip_ctlinput, 128 .pr_ctloutput = rip_ctloutput, 129 130 .pr_ctlport = cpu0_ctlport, 131 .pr_usrreqs = &rip_usrreqs 132 }; 133 134 static const struct protosw in_mobile_protosw = 135 { 136 .pr_type = SOCK_RAW, 137 .pr_domain = &inetdomain, 138 .pr_protocol = IPPROTO_MOBILE, 139 .pr_flags = PR_ATOMIC|PR_ADDR, 140 141 .pr_input = gre_mobile_input, 142 .pr_output = rip_output, 143 .pr_ctlinput = rip_ctlinput, 144 .pr_ctloutput = rip_ctloutput, 145 146 .pr_ctlport = cpu0_ctlport, 147 .pr_usrreqs = &rip_usrreqs 148 }; 149 150 #endif 151 152 SYSCTL_DECL(_net_link); 153 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 154 "Generic Routing Encapsulation"); 155 #ifndef MAX_GRE_NEST 156 /* 157 * This macro controls the default upper limitation on nesting of gre tunnels. 158 * Since, setting a large value to this macro with a careless configuration 159 * may introduce system crash, we don't allow any nestings by default. 160 * If you need to configure nested gre tunnels, you can define this macro 161 * in your kernel configuration file. However, if you do so, please be 162 * careful to configure the tunnels so that it won't make a loop. 163 */ 164 #define MAX_GRE_NEST 1 165 #endif 166 static int max_gre_nesting = MAX_GRE_NEST; 167 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 168 &max_gre_nesting, 0, "Max nested tunnels"); 169 170 /* ARGSUSED */ 171 static void 172 greattach(void) 173 { 174 175 LIST_INIT(&gre_softc_list); 176 if_clone_attach(&gre_cloner); 177 } 178 179 static int 180 gre_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused) 181 { 182 struct gre_softc *sc; 183 184 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 185 memset(sc, 0, sizeof(struct gre_softc)); 186 187 sc->sc_if.if_softc = sc; 188 if_initname(&(sc->sc_if), GRENAME, unit); 189 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 190 sc->sc_if.if_type = IFT_OTHER; 191 sc->sc_if.if_addrlen = 0; 192 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 193 sc->sc_if.if_mtu = GREMTU; 194 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 195 sc->sc_if.if_output = gre_output; 196 sc->sc_if.if_ioctl = gre_ioctl; 197 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 198 sc->g_proto = IPPROTO_GRE; 199 sc->sc_if.if_flags |= IFF_LINK0; 200 sc->encap = NULL; 201 sc->called = 0; 202 if_attach(&sc->sc_if, NULL); 203 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 204 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 205 return (0); 206 } 207 208 static int 209 gre_clone_destroy(struct ifnet *ifp) 210 { 211 struct gre_softc *sc = ifp->if_softc; 212 213 #ifdef INET 214 if (sc->encap != NULL) 215 encap_detach(sc->encap); 216 #endif 217 LIST_REMOVE(sc, sc_list); 218 bpfdetach(ifp); 219 if_detach(ifp); 220 221 kfree(sc, M_GRE); 222 223 return 0; 224 } 225 226 /* 227 * The output routine. Takes a packet and encapsulates it in the protocol 228 * given by sc->g_proto. See also RFC 1701 and RFC 2004 229 */ 230 static int 231 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 232 struct rtentry *rt) 233 { 234 int error = 0; 235 struct gre_softc *sc = ifp->if_softc; 236 struct greip *gh; 237 struct ip *ip; 238 u_short etype = 0; 239 struct mobile_h mob_h; 240 241 /* 242 * gre may cause infinite recursion calls when misconfigured. 243 * We'll prevent this by introducing upper limit. 244 */ 245 if (++(sc->called) > max_gre_nesting) { 246 kprintf("%s: gre_output: recursively called too many " 247 "times(%d)\n", if_name(&sc->sc_if), sc->called); 248 m_freem(m); 249 error = EIO; /* is there better errno? */ 250 goto end; 251 } 252 253 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 254 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 255 m_freem(m); 256 error = ENETDOWN; 257 goto end; 258 } 259 260 gh = NULL; 261 ip = NULL; 262 263 if (ifp->if_bpf) { 264 bpf_gettoken(); 265 if (ifp->if_bpf) { 266 uint32_t af = dst->sa_family; 267 268 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 269 } 270 bpf_reltoken(); 271 } 272 273 m->m_flags &= ~(M_BCAST|M_MCAST); 274 275 if (sc->g_proto == IPPROTO_MOBILE) { 276 if (dst->sa_family == AF_INET) { 277 struct mbuf *m0; 278 int msiz; 279 280 ip = mtod(m, struct ip *); 281 282 /* 283 * RFC2004 specifies that fragmented datagrams shouldn't 284 * be encapsulated. 285 */ 286 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 287 IF_DROP(&ifp->if_snd); 288 m_freem(m); 289 error = EINVAL; /* is there better errno? */ 290 goto end; 291 } 292 memset(&mob_h, 0, MOB_H_SIZ_L); 293 mob_h.proto = (ip->ip_p) << 8; 294 mob_h.odst = ip->ip_dst.s_addr; 295 ip->ip_dst.s_addr = sc->g_dst.s_addr; 296 297 /* 298 * If the packet comes from our host, we only change 299 * the destination address in the IP header. 300 * Else we also need to save and change the source 301 */ 302 if (in_hosteq(ip->ip_src, sc->g_src)) { 303 msiz = MOB_H_SIZ_S; 304 } else { 305 mob_h.proto |= MOB_H_SBIT; 306 mob_h.osrc = ip->ip_src.s_addr; 307 ip->ip_src.s_addr = sc->g_src.s_addr; 308 msiz = MOB_H_SIZ_L; 309 } 310 mob_h.proto = htons(mob_h.proto); 311 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 312 313 if ((m->m_data - msiz) < m->m_pktdat) { 314 /* need new mbuf */ 315 MGETHDR(m0, MB_DONTWAIT, MT_HEADER); 316 if (m0 == NULL) { 317 IF_DROP(&ifp->if_snd); 318 m_freem(m); 319 error = ENOBUFS; 320 goto end; 321 } 322 m0->m_next = m; 323 m->m_data += sizeof(struct ip); 324 m->m_len -= sizeof(struct ip); 325 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 326 m0->m_len = msiz + sizeof(struct ip); 327 m0->m_data += max_linkhdr; 328 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 329 sizeof(struct ip)); 330 m = m0; 331 } else { /* we have some space left in the old one */ 332 m->m_data -= msiz; 333 m->m_len += msiz; 334 m->m_pkthdr.len += msiz; 335 bcopy(ip, mtod(m, caddr_t), 336 sizeof(struct ip)); 337 } 338 ip = mtod(m, struct ip *); 339 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 340 ip->ip_len = ntohs(ip->ip_len) + msiz; 341 } else { /* AF_INET */ 342 IF_DROP(&ifp->if_snd); 343 m_freem(m); 344 error = EINVAL; 345 goto end; 346 } 347 } else if (sc->g_proto == IPPROTO_GRE) { 348 switch (dst->sa_family) { 349 case AF_INET: 350 ip = mtod(m, struct ip *); 351 etype = ETHERTYPE_IP; 352 break; 353 default: 354 IF_DROP(&ifp->if_snd); 355 m_freem(m); 356 error = EAFNOSUPPORT; 357 goto end; 358 } 359 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 360 } else { 361 IF_DROP(&ifp->if_snd); 362 m_freem(m); 363 error = EINVAL; 364 goto end; 365 } 366 367 if (m == NULL) { /* impossible */ 368 IF_DROP(&ifp->if_snd); 369 error = ENOBUFS; 370 goto end; 371 } 372 373 gh = mtod(m, struct greip *); 374 if (sc->g_proto == IPPROTO_GRE) { 375 /* we don't have any GRE flags for now */ 376 377 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 378 gh->gi_ptype = htons(etype); 379 } 380 381 gh->gi_pr = sc->g_proto; 382 if (sc->g_proto != IPPROTO_MOBILE) { 383 gh->gi_src = sc->g_src; 384 gh->gi_dst = sc->g_dst; 385 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 386 ((struct ip*)gh)->ip_ttl = GRE_TTL; 387 ((struct ip*)gh)->ip_tos = ip->ip_tos; 388 ((struct ip*)gh)->ip_id = ip->ip_id; 389 gh->gi_len = m->m_pkthdr.len; 390 } 391 392 ifp->if_opackets++; 393 ifp->if_obytes += m->m_pkthdr.len; 394 /* send it off */ 395 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 396 end: 397 sc->called = 0; 398 if (error) 399 ifp->if_oerrors++; 400 return (error); 401 } 402 403 static int 404 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 405 struct rtentry *rt) 406 { 407 int error; 408 409 ifnet_serialize_tx(ifp); 410 error = gre_output_serialized(ifp, m, dst, rt); 411 ifnet_deserialize_tx(ifp); 412 413 return error; 414 } 415 416 static int 417 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 418 { 419 struct ifreq *ifr = (struct ifreq *)data; 420 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 421 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 422 struct gre_softc *sc = ifp->if_softc; 423 struct sockaddr_in si; 424 struct sockaddr *sa = NULL; 425 int error; 426 struct sockaddr_in sp, sm, dp, dm; 427 428 error = 0; 429 430 crit_enter(); 431 switch (cmd) { 432 case SIOCSIFADDR: 433 ifp->if_flags |= IFF_UP; 434 break; 435 case SIOCSIFDSTADDR: 436 break; 437 case SIOCSIFFLAGS: 438 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 439 break; 440 if ((ifr->ifr_flags & IFF_LINK0) != 0) 441 sc->g_proto = IPPROTO_GRE; 442 else 443 sc->g_proto = IPPROTO_MOBILE; 444 goto recompute; 445 case SIOCSIFMTU: 446 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 447 break; 448 if (ifr->ifr_mtu < 576) { 449 error = EINVAL; 450 break; 451 } 452 ifp->if_mtu = ifr->ifr_mtu; 453 break; 454 case SIOCGIFMTU: 455 ifr->ifr_mtu = sc->sc_if.if_mtu; 456 break; 457 case SIOCADDMULTI: 458 case SIOCDELMULTI: 459 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 460 break; 461 if (ifr == NULL) { 462 error = EAFNOSUPPORT; 463 break; 464 } 465 switch (ifr->ifr_addr.sa_family) { 466 #ifdef INET 467 case AF_INET: 468 break; 469 #endif 470 default: 471 error = EAFNOSUPPORT; 472 break; 473 } 474 break; 475 case GRESPROTO: 476 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 477 break; 478 sc->g_proto = ifr->ifr_flags; 479 switch (sc->g_proto) { 480 case IPPROTO_GRE: 481 ifp->if_flags |= IFF_LINK0; 482 break; 483 case IPPROTO_MOBILE: 484 ifp->if_flags &= ~IFF_LINK0; 485 break; 486 default: 487 error = EPROTONOSUPPORT; 488 break; 489 } 490 goto recompute; 491 case GREGPROTO: 492 ifr->ifr_flags = sc->g_proto; 493 break; 494 case GRESADDRS: 495 case GRESADDRD: 496 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 497 break; 498 /* 499 * set tunnel endpoints, compute a less specific route 500 * to the remote end and mark if as up 501 */ 502 sa = &ifr->ifr_addr; 503 if (cmd == GRESADDRS) 504 sc->g_src = (satosin(sa))->sin_addr; 505 if (cmd == GRESADDRD) 506 sc->g_dst = (satosin(sa))->sin_addr; 507 recompute: 508 #ifdef INET 509 if (sc->encap != NULL) { 510 encap_detach(sc->encap); 511 sc->encap = NULL; 512 } 513 #endif 514 if ((sc->g_src.s_addr != INADDR_ANY) && 515 (sc->g_dst.s_addr != INADDR_ANY)) { 516 bzero(&sp, sizeof(sp)); 517 bzero(&sm, sizeof(sm)); 518 bzero(&dp, sizeof(dp)); 519 bzero(&dm, sizeof(dm)); 520 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 521 sizeof(struct sockaddr_in); 522 sp.sin_family = sm.sin_family = dp.sin_family = 523 dm.sin_family = AF_INET; 524 sp.sin_addr = sc->g_src; 525 dp.sin_addr = sc->g_dst; 526 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 527 INADDR_BROADCAST; 528 #ifdef INET 529 sc->encap = encap_attach(AF_INET, sc->g_proto, 530 sintosa(&sp), sintosa(&sm), sintosa(&dp), 531 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 532 &in_gre_protosw : &in_mobile_protosw, sc); 533 if (sc->encap == NULL) 534 kprintf("%s: unable to attach encap\n", 535 if_name(&sc->sc_if)); 536 #endif 537 if (sc->route.ro_rt != 0) /* free old route */ 538 RTFREE(sc->route.ro_rt); 539 if (gre_compute_route(sc) == 0) 540 ifp->if_flags |= IFF_RUNNING; 541 else 542 ifp->if_flags &= ~IFF_RUNNING; 543 } 544 break; 545 case GREGADDRS: 546 memset(&si, 0, sizeof(si)); 547 si.sin_family = AF_INET; 548 si.sin_len = sizeof(struct sockaddr_in); 549 si.sin_addr.s_addr = sc->g_src.s_addr; 550 sa = sintosa(&si); 551 ifr->ifr_addr = *sa; 552 break; 553 case GREGADDRD: 554 memset(&si, 0, sizeof(si)); 555 si.sin_family = AF_INET; 556 si.sin_len = sizeof(struct sockaddr_in); 557 si.sin_addr.s_addr = sc->g_dst.s_addr; 558 sa = sintosa(&si); 559 ifr->ifr_addr = *sa; 560 break; 561 case SIOCSIFPHYADDR: 562 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 563 break; 564 if (aifr->ifra_addr.sin_family != AF_INET || 565 aifr->ifra_dstaddr.sin_family != AF_INET) { 566 error = EAFNOSUPPORT; 567 break; 568 } 569 if (aifr->ifra_addr.sin_len != sizeof(si) || 570 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 571 error = EINVAL; 572 break; 573 } 574 sc->g_src = aifr->ifra_addr.sin_addr; 575 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 576 goto recompute; 577 case SIOCSLIFPHYADDR: 578 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 579 break; 580 if (lifr->addr.ss_family != AF_INET || 581 lifr->dstaddr.ss_family != AF_INET) { 582 error = EAFNOSUPPORT; 583 break; 584 } 585 if (lifr->addr.ss_len != sizeof(si) || 586 lifr->dstaddr.ss_len != sizeof(si)) { 587 error = EINVAL; 588 break; 589 } 590 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 591 sc->g_dst = 592 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 593 goto recompute; 594 case SIOCDIFPHYADDR: 595 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 596 break; 597 sc->g_src.s_addr = INADDR_ANY; 598 sc->g_dst.s_addr = INADDR_ANY; 599 goto recompute; 600 case SIOCGLIFPHYADDR: 601 if (sc->g_src.s_addr == INADDR_ANY || 602 sc->g_dst.s_addr == INADDR_ANY) { 603 error = EADDRNOTAVAIL; 604 break; 605 } 606 memset(&si, 0, sizeof(si)); 607 si.sin_family = AF_INET; 608 si.sin_len = sizeof(struct sockaddr_in); 609 si.sin_addr.s_addr = sc->g_src.s_addr; 610 memcpy(&lifr->addr, &si, sizeof(si)); 611 si.sin_addr.s_addr = sc->g_dst.s_addr; 612 memcpy(&lifr->dstaddr, &si, sizeof(si)); 613 break; 614 case SIOCGIFPSRCADDR: 615 if (sc->g_src.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_src.s_addr; 623 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 624 break; 625 case SIOCGIFPDSTADDR: 626 if (sc->g_dst.s_addr == INADDR_ANY) { 627 error = EADDRNOTAVAIL; 628 break; 629 } 630 memset(&si, 0, sizeof(si)); 631 si.sin_family = AF_INET; 632 si.sin_len = sizeof(struct sockaddr_in); 633 si.sin_addr.s_addr = sc->g_dst.s_addr; 634 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 635 break; 636 default: 637 error = EINVAL; 638 break; 639 } 640 641 crit_exit(); 642 return (error); 643 } 644 645 /* 646 * computes a route to our destination that is not the one 647 * which would be taken by ip_output(), as this one will loop back to 648 * us. If the interface is p2p as a--->b, then a routing entry exists 649 * If we now send a packet to b (e.g. ping b), this will come down here 650 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 651 * if_gre. 652 * Goal here is to compute a route to b that is less specific than 653 * a-->b. We know that this one exists as in normal operation we have 654 * at least a default route which matches. 655 */ 656 static int 657 gre_compute_route(struct gre_softc *sc) 658 { 659 struct route *ro; 660 u_int32_t a, b, c; 661 662 ro = &sc->route; 663 664 memset(ro, 0, sizeof(struct route)); 665 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 666 ro->ro_dst.sa_family = AF_INET; 667 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 668 669 /* 670 * toggle last bit, so our interface is not found, but a less 671 * specific route. I'd rather like to specify a shorter mask, 672 * but this is not possible. Should work though. XXX 673 * there is a simpler way ... 674 */ 675 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 676 a = ntohl(sc->g_dst.s_addr); 677 b = a & 0x01; 678 c = a & 0xfffffffe; 679 b = b ^ 0x01; 680 a = b | c; 681 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 682 = htonl(a); 683 } 684 685 #ifdef DIAGNOSTIC 686 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 687 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 688 #endif 689 690 rtalloc(ro); 691 692 /* 693 * check if this returned a route at all and this route is no 694 * recursion to ourself 695 */ 696 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 697 #ifdef DIAGNOSTIC 698 if (ro->ro_rt == NULL) 699 kprintf(" - no route found!\n"); 700 else 701 kprintf(" - route loops back to ourself!\n"); 702 #endif 703 return EADDRNOTAVAIL; 704 } 705 706 /* 707 * now change it back - else ip_output will just drop 708 * the route and search one to this interface ... 709 */ 710 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 711 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 712 713 #ifdef DIAGNOSTIC 714 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 715 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 716 kprintf("\n"); 717 #endif 718 719 return 0; 720 } 721 722 /* 723 * do a checksum of a buffer - much like in_cksum, which operates on 724 * mbufs. 725 */ 726 u_short 727 gre_in_cksum(u_short *p, u_int len) 728 { 729 u_int sum = 0; 730 int nwords = len >> 1; 731 732 while (nwords-- != 0) 733 sum += *p++; 734 735 if (len & 1) { 736 union { 737 u_short w; 738 u_char c[2]; 739 } u; 740 u.c[0] = *(u_char *)p; 741 u.c[1] = 0; 742 sum += u.w; 743 } 744 745 /* end-around-carry */ 746 sum = (sum >> 16) + (sum & 0xffff); 747 sum += (sum >> 16); 748 return (~sum); 749 } 750 751 static int 752 gremodevent(module_t mod, int type, void *data) 753 { 754 755 switch (type) { 756 case MOD_LOAD: 757 greattach(); 758 break; 759 case MOD_UNLOAD: 760 if_clone_detach(&gre_cloner); 761 762 while (!LIST_EMPTY(&gre_softc_list)) 763 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 764 765 break; 766 } 767 return 0; 768 } 769 770 static moduledata_t gre_mod = { 771 "if_gre", 772 gremodevent, 773 0 774 }; 775 776 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 777 MODULE_VERSION(if_gre, 1); 778