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, caddr_t); 105 static int 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 118 119 extern struct domain inetdomain; 120 121 static const struct protosw in_gre_protosw = 122 { 123 .pr_type = SOCK_RAW, 124 .pr_domain = &inetdomain, 125 .pr_protocol = IPPROTO_GRE, 126 .pr_flags = PR_ATOMIC|PR_ADDR, 127 128 .pr_input = gre_input, 129 .pr_output = rip_output, 130 .pr_ctlinput = rip_ctlinput, 131 .pr_ctloutput = rip_ctloutput, 132 133 .pr_ctlport = cpu0_ctlport, 134 .pr_usrreqs = &rip_usrreqs 135 }; 136 137 static const struct protosw in_mobile_protosw = 138 { 139 .pr_type = SOCK_RAW, 140 .pr_domain = &inetdomain, 141 .pr_protocol = IPPROTO_MOBILE, 142 .pr_flags = PR_ATOMIC|PR_ADDR, 143 144 .pr_input = gre_mobile_input, 145 .pr_output = rip_output, 146 .pr_ctlinput = rip_ctlinput, 147 .pr_ctloutput = rip_ctloutput, 148 149 .pr_ctlport = cpu0_ctlport, 150 .pr_usrreqs = &rip_usrreqs 151 }; 152 153 #endif 154 155 SYSCTL_DECL(_net_link); 156 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 157 "Generic Routing Encapsulation"); 158 #ifndef MAX_GRE_NEST 159 /* 160 * This macro controls the default upper limitation on nesting of gre tunnels. 161 * Since, setting a large value to this macro with a careless configuration 162 * may introduce system crash, we don't allow any nestings by default. 163 * If you need to configure nested gre tunnels, you can define this macro 164 * in your kernel configuration file. However, if you do so, please be 165 * careful to configure the tunnels so that it won't make a loop. 166 */ 167 #define MAX_GRE_NEST 1 168 #endif 169 static int max_gre_nesting = MAX_GRE_NEST; 170 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 171 &max_gre_nesting, 0, "Max nested tunnels"); 172 173 /* ARGSUSED */ 174 static void 175 greattach(void) 176 { 177 178 LIST_INIT(&gre_softc_list); 179 if_clone_attach(&gre_cloner); 180 } 181 182 static int 183 gre_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused) 184 { 185 struct gre_softc *sc; 186 187 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 188 memset(sc, 0, sizeof(struct gre_softc)); 189 190 sc->sc_if.if_softc = sc; 191 if_initname(&(sc->sc_if), GRENAME, unit); 192 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 193 sc->sc_if.if_type = IFT_OTHER; 194 sc->sc_if.if_addrlen = 0; 195 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 196 sc->sc_if.if_mtu = GREMTU; 197 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 198 sc->sc_if.if_output = gre_output; 199 sc->sc_if.if_ioctl = gre_ioctl; 200 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 201 sc->g_proto = IPPROTO_GRE; 202 sc->sc_if.if_flags |= IFF_LINK0; 203 sc->encap = NULL; 204 sc->called = 0; 205 if_attach(&sc->sc_if, NULL); 206 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 207 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 208 return (0); 209 } 210 211 static int 212 gre_clone_destroy(struct ifnet *ifp) 213 { 214 struct gre_softc *sc = ifp->if_softc; 215 216 #ifdef INET 217 if (sc->encap != NULL) 218 encap_detach(sc->encap); 219 #endif 220 LIST_REMOVE(sc, sc_list); 221 bpfdetach(ifp); 222 if_detach(ifp); 223 224 kfree(sc, M_GRE); 225 226 return 0; 227 } 228 229 /* 230 * The output routine. Takes a packet and encapsulates it in the protocol 231 * given by sc->g_proto. See also RFC 1701 and RFC 2004 232 */ 233 static int 234 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 235 struct rtentry *rt) 236 { 237 int error = 0; 238 struct gre_softc *sc = ifp->if_softc; 239 struct greip *gh; 240 struct ip *ip; 241 u_char osrc; 242 u_short etype = 0; 243 struct mobile_h mob_h; 244 245 /* 246 * gre may cause infinite recursion calls when misconfigured. 247 * We'll prevent this by introducing upper limit. 248 */ 249 if (++(sc->called) > max_gre_nesting) { 250 kprintf("%s: gre_output: recursively called too many " 251 "times(%d)\n", if_name(&sc->sc_if), sc->called); 252 m_freem(m); 253 error = EIO; /* is there better errno? */ 254 goto end; 255 } 256 257 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 258 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 259 m_freem(m); 260 error = ENETDOWN; 261 goto end; 262 } 263 264 gh = NULL; 265 ip = NULL; 266 osrc = 0; 267 268 if (ifp->if_bpf) { 269 uint32_t af = dst->sa_family; 270 271 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 272 } 273 274 m->m_flags &= ~(M_BCAST|M_MCAST); 275 276 if (sc->g_proto == IPPROTO_MOBILE) { 277 if (dst->sa_family == AF_INET) { 278 struct mbuf *m0; 279 int msiz; 280 281 ip = mtod(m, struct ip *); 282 283 /* 284 * RFC2004 specifies that fragmented datagrams shouldn't 285 * be encapsulated. 286 */ 287 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 288 IF_DROP(&ifp->if_snd); 289 m_freem(m); 290 error = EINVAL; /* is there better errno? */ 291 goto end; 292 } 293 memset(&mob_h, 0, MOB_H_SIZ_L); 294 mob_h.proto = (ip->ip_p) << 8; 295 mob_h.odst = ip->ip_dst.s_addr; 296 ip->ip_dst.s_addr = sc->g_dst.s_addr; 297 298 /* 299 * If the packet comes from our host, we only change 300 * the destination address in the IP header. 301 * Else we also need to save and change the source 302 */ 303 if (in_hosteq(ip->ip_src, sc->g_src)) { 304 msiz = MOB_H_SIZ_S; 305 } else { 306 mob_h.proto |= MOB_H_SBIT; 307 mob_h.osrc = ip->ip_src.s_addr; 308 ip->ip_src.s_addr = sc->g_src.s_addr; 309 msiz = MOB_H_SIZ_L; 310 } 311 mob_h.proto = htons(mob_h.proto); 312 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 313 314 if ((m->m_data - msiz) < m->m_pktdat) { 315 /* need new mbuf */ 316 MGETHDR(m0, MB_DONTWAIT, MT_HEADER); 317 if (m0 == NULL) { 318 IF_DROP(&ifp->if_snd); 319 m_freem(m); 320 error = ENOBUFS; 321 goto end; 322 } 323 m0->m_next = m; 324 m->m_data += sizeof(struct ip); 325 m->m_len -= sizeof(struct ip); 326 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 327 m0->m_len = msiz + sizeof(struct ip); 328 m0->m_data += max_linkhdr; 329 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 330 sizeof(struct ip)); 331 m = m0; 332 } else { /* we have some space left in the old one */ 333 m->m_data -= msiz; 334 m->m_len += msiz; 335 m->m_pkthdr.len += msiz; 336 bcopy(ip, mtod(m, caddr_t), 337 sizeof(struct ip)); 338 } 339 ip = mtod(m, struct ip *); 340 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 341 ip->ip_len = ntohs(ip->ip_len) + msiz; 342 } else { /* AF_INET */ 343 IF_DROP(&ifp->if_snd); 344 m_freem(m); 345 error = EINVAL; 346 goto end; 347 } 348 } else if (sc->g_proto == IPPROTO_GRE) { 349 switch (dst->sa_family) { 350 case AF_INET: 351 ip = mtod(m, struct ip *); 352 etype = ETHERTYPE_IP; 353 break; 354 #ifdef NETATALK 355 case AF_APPLETALK: 356 etype = ETHERTYPE_ATALK; 357 break; 358 #endif 359 #ifdef NS 360 case AF_NS: 361 etype = ETHERTYPE_NS; 362 break; 363 #endif 364 default: 365 IF_DROP(&ifp->if_snd); 366 m_freem(m); 367 error = EAFNOSUPPORT; 368 goto end; 369 } 370 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 371 } else { 372 IF_DROP(&ifp->if_snd); 373 m_freem(m); 374 error = EINVAL; 375 goto end; 376 } 377 378 if (m == NULL) { /* impossible */ 379 IF_DROP(&ifp->if_snd); 380 error = ENOBUFS; 381 goto end; 382 } 383 384 gh = mtod(m, struct greip *); 385 if (sc->g_proto == IPPROTO_GRE) { 386 /* we don't have any GRE flags for now */ 387 388 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 389 gh->gi_ptype = htons(etype); 390 } 391 392 gh->gi_pr = sc->g_proto; 393 if (sc->g_proto != IPPROTO_MOBILE) { 394 gh->gi_src = sc->g_src; 395 gh->gi_dst = sc->g_dst; 396 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 397 ((struct ip*)gh)->ip_ttl = GRE_TTL; 398 ((struct ip*)gh)->ip_tos = ip->ip_tos; 399 ((struct ip*)gh)->ip_id = ip->ip_id; 400 gh->gi_len = m->m_pkthdr.len; 401 } 402 403 ifp->if_opackets++; 404 ifp->if_obytes += m->m_pkthdr.len; 405 /* send it off */ 406 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 407 end: 408 sc->called = 0; 409 if (error) 410 ifp->if_oerrors++; 411 return (error); 412 } 413 414 static int 415 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 416 struct rtentry *rt) 417 { 418 int error; 419 420 ifnet_serialize_tx(ifp); 421 error = gre_output_serialized(ifp, m, dst, rt); 422 ifnet_deserialize_tx(ifp); 423 424 return error; 425 } 426 427 static int 428 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 429 { 430 struct ifreq *ifr = (struct ifreq *)data; 431 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 432 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 433 struct gre_softc *sc = ifp->if_softc; 434 struct sockaddr_in si; 435 struct sockaddr *sa = NULL; 436 int error; 437 struct sockaddr_in sp, sm, dp, dm; 438 439 error = 0; 440 441 crit_enter(); 442 switch (cmd) { 443 case SIOCSIFADDR: 444 ifp->if_flags |= IFF_UP; 445 break; 446 case SIOCSIFDSTADDR: 447 break; 448 case SIOCSIFFLAGS: 449 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 450 break; 451 if ((ifr->ifr_flags & IFF_LINK0) != 0) 452 sc->g_proto = IPPROTO_GRE; 453 else 454 sc->g_proto = IPPROTO_MOBILE; 455 goto recompute; 456 case SIOCSIFMTU: 457 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 458 break; 459 if (ifr->ifr_mtu < 576) { 460 error = EINVAL; 461 break; 462 } 463 ifp->if_mtu = ifr->ifr_mtu; 464 break; 465 case SIOCGIFMTU: 466 ifr->ifr_mtu = sc->sc_if.if_mtu; 467 break; 468 case SIOCADDMULTI: 469 case SIOCDELMULTI: 470 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 471 break; 472 if (ifr == 0) { 473 error = EAFNOSUPPORT; 474 break; 475 } 476 switch (ifr->ifr_addr.sa_family) { 477 #ifdef INET 478 case AF_INET: 479 break; 480 #endif 481 default: 482 error = EAFNOSUPPORT; 483 break; 484 } 485 break; 486 case GRESPROTO: 487 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 488 break; 489 sc->g_proto = ifr->ifr_flags; 490 switch (sc->g_proto) { 491 case IPPROTO_GRE: 492 ifp->if_flags |= IFF_LINK0; 493 break; 494 case IPPROTO_MOBILE: 495 ifp->if_flags &= ~IFF_LINK0; 496 break; 497 default: 498 error = EPROTONOSUPPORT; 499 break; 500 } 501 goto recompute; 502 case GREGPROTO: 503 ifr->ifr_flags = sc->g_proto; 504 break; 505 case GRESADDRS: 506 case GRESADDRD: 507 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 508 break; 509 /* 510 * set tunnel endpoints, compute a less specific route 511 * to the remote end and mark if as up 512 */ 513 sa = &ifr->ifr_addr; 514 if (cmd == GRESADDRS) 515 sc->g_src = (satosin(sa))->sin_addr; 516 if (cmd == GRESADDRD) 517 sc->g_dst = (satosin(sa))->sin_addr; 518 recompute: 519 #ifdef INET 520 if (sc->encap != NULL) { 521 encap_detach(sc->encap); 522 sc->encap = NULL; 523 } 524 #endif 525 if ((sc->g_src.s_addr != INADDR_ANY) && 526 (sc->g_dst.s_addr != INADDR_ANY)) { 527 bzero(&sp, sizeof(sp)); 528 bzero(&sm, sizeof(sm)); 529 bzero(&dp, sizeof(dp)); 530 bzero(&dm, sizeof(dm)); 531 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 532 sizeof(struct sockaddr_in); 533 sp.sin_family = sm.sin_family = dp.sin_family = 534 dm.sin_family = AF_INET; 535 sp.sin_addr = sc->g_src; 536 dp.sin_addr = sc->g_dst; 537 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 538 INADDR_BROADCAST; 539 #ifdef INET 540 sc->encap = encap_attach(AF_INET, sc->g_proto, 541 sintosa(&sp), sintosa(&sm), sintosa(&dp), 542 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 543 &in_gre_protosw : &in_mobile_protosw, sc); 544 if (sc->encap == NULL) 545 kprintf("%s: unable to attach encap\n", 546 if_name(&sc->sc_if)); 547 #endif 548 if (sc->route.ro_rt != 0) /* free old route */ 549 RTFREE(sc->route.ro_rt); 550 if (gre_compute_route(sc) == 0) 551 ifp->if_flags |= IFF_RUNNING; 552 else 553 ifp->if_flags &= ~IFF_RUNNING; 554 } 555 break; 556 case GREGADDRS: 557 memset(&si, 0, sizeof(si)); 558 si.sin_family = AF_INET; 559 si.sin_len = sizeof(struct sockaddr_in); 560 si.sin_addr.s_addr = sc->g_src.s_addr; 561 sa = sintosa(&si); 562 ifr->ifr_addr = *sa; 563 break; 564 case GREGADDRD: 565 memset(&si, 0, sizeof(si)); 566 si.sin_family = AF_INET; 567 si.sin_len = sizeof(struct sockaddr_in); 568 si.sin_addr.s_addr = sc->g_dst.s_addr; 569 sa = sintosa(&si); 570 ifr->ifr_addr = *sa; 571 break; 572 case SIOCSIFPHYADDR: 573 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 574 break; 575 if (aifr->ifra_addr.sin_family != AF_INET || 576 aifr->ifra_dstaddr.sin_family != AF_INET) { 577 error = EAFNOSUPPORT; 578 break; 579 } 580 if (aifr->ifra_addr.sin_len != sizeof(si) || 581 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 582 error = EINVAL; 583 break; 584 } 585 sc->g_src = aifr->ifra_addr.sin_addr; 586 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 587 goto recompute; 588 case SIOCSLIFPHYADDR: 589 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 590 break; 591 if (lifr->addr.ss_family != AF_INET || 592 lifr->dstaddr.ss_family != AF_INET) { 593 error = EAFNOSUPPORT; 594 break; 595 } 596 if (lifr->addr.ss_len != sizeof(si) || 597 lifr->dstaddr.ss_len != sizeof(si)) { 598 error = EINVAL; 599 break; 600 } 601 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 602 sc->g_dst = 603 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 604 goto recompute; 605 case SIOCDIFPHYADDR: 606 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 607 break; 608 sc->g_src.s_addr = INADDR_ANY; 609 sc->g_dst.s_addr = INADDR_ANY; 610 goto recompute; 611 case SIOCGLIFPHYADDR: 612 if (sc->g_src.s_addr == INADDR_ANY || 613 sc->g_dst.s_addr == INADDR_ANY) { 614 error = EADDRNOTAVAIL; 615 break; 616 } 617 memset(&si, 0, sizeof(si)); 618 si.sin_family = AF_INET; 619 si.sin_len = sizeof(struct sockaddr_in); 620 si.sin_addr.s_addr = sc->g_src.s_addr; 621 memcpy(&lifr->addr, &si, sizeof(si)); 622 si.sin_addr.s_addr = sc->g_dst.s_addr; 623 memcpy(&lifr->dstaddr, &si, sizeof(si)); 624 break; 625 case SIOCGIFPSRCADDR: 626 if (sc->g_src.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_src.s_addr; 634 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 635 break; 636 case SIOCGIFPDSTADDR: 637 if (sc->g_dst.s_addr == INADDR_ANY) { 638 error = EADDRNOTAVAIL; 639 break; 640 } 641 memset(&si, 0, sizeof(si)); 642 si.sin_family = AF_INET; 643 si.sin_len = sizeof(struct sockaddr_in); 644 si.sin_addr.s_addr = sc->g_dst.s_addr; 645 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 646 break; 647 default: 648 error = EINVAL; 649 break; 650 } 651 652 crit_exit(); 653 return (error); 654 } 655 656 /* 657 * computes a route to our destination that is not the one 658 * which would be taken by ip_output(), as this one will loop back to 659 * us. If the interface is p2p as a--->b, then a routing entry exists 660 * If we now send a packet to b (e.g. ping b), this will come down here 661 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 662 * if_gre. 663 * Goal here is to compute a route to b that is less specific than 664 * a-->b. We know that this one exists as in normal operation we have 665 * at least a default route which matches. 666 */ 667 static int 668 gre_compute_route(struct gre_softc *sc) 669 { 670 struct route *ro; 671 u_int32_t a, b, c; 672 673 ro = &sc->route; 674 675 memset(ro, 0, sizeof(struct route)); 676 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 677 ro->ro_dst.sa_family = AF_INET; 678 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 679 680 /* 681 * toggle last bit, so our interface is not found, but a less 682 * specific route. I'd rather like to specify a shorter mask, 683 * but this is not possible. Should work though. XXX 684 * there is a simpler way ... 685 */ 686 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 687 a = ntohl(sc->g_dst.s_addr); 688 b = a & 0x01; 689 c = a & 0xfffffffe; 690 b = b ^ 0x01; 691 a = b | c; 692 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 693 = htonl(a); 694 } 695 696 #ifdef DIAGNOSTIC 697 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 698 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 699 #endif 700 701 rtalloc(ro); 702 703 /* 704 * check if this returned a route at all and this route is no 705 * recursion to ourself 706 */ 707 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 708 #ifdef DIAGNOSTIC 709 if (ro->ro_rt == NULL) 710 kprintf(" - no route found!\n"); 711 else 712 kprintf(" - route loops back to ourself!\n"); 713 #endif 714 return EADDRNOTAVAIL; 715 } 716 717 /* 718 * now change it back - else ip_output will just drop 719 * the route and search one to this interface ... 720 */ 721 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 722 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 723 724 #ifdef DIAGNOSTIC 725 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 726 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 727 kprintf("\n"); 728 #endif 729 730 return 0; 731 } 732 733 /* 734 * do a checksum of a buffer - much like in_cksum, which operates on 735 * mbufs. 736 */ 737 u_short 738 gre_in_cksum(u_short *p, u_int len) 739 { 740 u_int sum = 0; 741 int nwords = len >> 1; 742 743 while (nwords-- != 0) 744 sum += *p++; 745 746 if (len & 1) { 747 union { 748 u_short w; 749 u_char c[2]; 750 } u; 751 u.c[0] = *(u_char *)p; 752 u.c[1] = 0; 753 sum += u.w; 754 } 755 756 /* end-around-carry */ 757 sum = (sum >> 16) + (sum & 0xffff); 758 sum += (sum >> 16); 759 return (~sum); 760 } 761 762 static int 763 gremodevent(module_t mod, int type, void *data) 764 { 765 766 switch (type) { 767 case MOD_LOAD: 768 greattach(); 769 break; 770 case MOD_UNLOAD: 771 if_clone_detach(&gre_cloner); 772 773 while (!LIST_EMPTY(&gre_softc_list)) 774 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 775 776 break; 777 } 778 return 0; 779 } 780 781 static moduledata_t gre_mod = { 782 "if_gre", 783 gremodevent, 784 0 785 }; 786 787 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 788 MODULE_VERSION(if_gre, 1); 789