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/ifq_var.h> 69 #include <net/route.h> 70 #include <net/if_clone.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 "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 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 99 100 struct gre_softc_head gre_softc_list; 101 102 static int gre_clone_create(struct if_clone *, int, caddr_t); 103 static int gre_clone_destroy(struct ifnet *); 104 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *); 105 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 106 struct rtentry *rt); 107 108 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", 109 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 110 111 static int gre_compute_route(struct gre_softc *sc); 112 113 static void greattach(void); 114 115 #ifdef INET 116 117 extern struct domain inetdomain; 118 119 static const struct protosw in_gre_protosw = 120 { 121 .pr_type = SOCK_RAW, 122 .pr_domain = &inetdomain, 123 .pr_protocol = IPPROTO_GRE, 124 .pr_flags = PR_ATOMIC|PR_ADDR, 125 126 .pr_input = gre_input, 127 .pr_output = rip_output, 128 .pr_ctlinput = rip_ctlinput, 129 .pr_ctloutput = rip_ctloutput, 130 131 .pr_ctlport = cpu0_ctlport, 132 .pr_usrreqs = &rip_usrreqs 133 }; 134 135 static const struct protosw in_mobile_protosw = 136 { 137 .pr_type = SOCK_RAW, 138 .pr_domain = &inetdomain, 139 .pr_protocol = IPPROTO_MOBILE, 140 .pr_flags = PR_ATOMIC|PR_ADDR, 141 142 .pr_input = gre_mobile_input, 143 .pr_output = rip_output, 144 .pr_ctlinput = rip_ctlinput, 145 .pr_ctloutput = rip_ctloutput, 146 147 .pr_ctlport = cpu0_ctlport, 148 .pr_usrreqs = &rip_usrreqs 149 }; 150 151 #endif 152 153 SYSCTL_DECL(_net_link); 154 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 155 "Generic Routing Encapsulation"); 156 #ifndef MAX_GRE_NEST 157 /* 158 * This macro controls the default upper limitation on nesting of gre tunnels. 159 * Since, setting a large value to this macro with a careless configuration 160 * may introduce system crash, we don't allow any nestings by default. 161 * If you need to configure nested gre tunnels, you can define this macro 162 * in your kernel configuration file. However, if you do so, please be 163 * careful to configure the tunnels so that it won't make a loop. 164 */ 165 #define MAX_GRE_NEST 1 166 #endif 167 static int max_gre_nesting = MAX_GRE_NEST; 168 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 169 &max_gre_nesting, 0, "Max nested tunnels"); 170 171 /* ARGSUSED */ 172 static void 173 greattach(void) 174 { 175 176 LIST_INIT(&gre_softc_list); 177 if_clone_attach(&gre_cloner); 178 } 179 180 static int 181 gre_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused) 182 { 183 struct gre_softc *sc; 184 185 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 186 memset(sc, 0, sizeof(struct gre_softc)); 187 188 sc->sc_if.if_softc = sc; 189 if_initname(&(sc->sc_if), GRENAME, unit); 190 ifq_set_maxlen(&sc->sc_if.if_snd, IFQ_MAXLEN); 191 sc->sc_if.if_type = IFT_OTHER; 192 sc->sc_if.if_addrlen = 0; 193 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 194 sc->sc_if.if_mtu = GREMTU; 195 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 196 sc->sc_if.if_output = gre_output; 197 sc->sc_if.if_ioctl = gre_ioctl; 198 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 199 sc->g_proto = IPPROTO_GRE; 200 sc->sc_if.if_flags |= IFF_LINK0; 201 sc->encap = NULL; 202 sc->called = 0; 203 if_attach(&sc->sc_if, NULL); 204 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 205 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 206 return (0); 207 } 208 209 static int 210 gre_clone_destroy(struct ifnet *ifp) 211 { 212 struct gre_softc *sc = ifp->if_softc; 213 214 #ifdef INET 215 if (sc->encap != NULL) 216 encap_detach(sc->encap); 217 #endif 218 LIST_REMOVE(sc, sc_list); 219 bpfdetach(ifp); 220 if_detach(ifp); 221 222 kfree(sc, M_GRE); 223 224 return 0; 225 } 226 227 /* 228 * The output routine. Takes a packet and encapsulates it in the protocol 229 * given by sc->g_proto. See also RFC 1701 and RFC 2004 230 */ 231 static int 232 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 233 struct rtentry *rt) 234 { 235 int error = 0; 236 struct gre_softc *sc = ifp->if_softc; 237 struct greip *gh; 238 struct ip *ip; 239 u_short etype = 0; 240 struct mobile_h mob_h; 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 kprintf("%s: gre_output: recursively called too many " 248 "times(%d)\n", if_name(&sc->sc_if), 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 | IFF_RUNNING)) == 0 || 255 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 256 m_freem(m); 257 error = ENETDOWN; 258 goto end; 259 } 260 261 gh = NULL; 262 ip = NULL; 263 264 if (ifp->if_bpf) { 265 bpf_gettoken(); 266 if (ifp->if_bpf) { 267 uint32_t af = dst->sa_family; 268 269 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 270 } 271 bpf_reltoken(); 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 default: 355 IF_DROP(&ifp->if_snd); 356 m_freem(m); 357 error = EAFNOSUPPORT; 358 goto end; 359 } 360 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 361 } else { 362 IF_DROP(&ifp->if_snd); 363 m_freem(m); 364 error = EINVAL; 365 goto end; 366 } 367 368 if (m == NULL) { /* impossible */ 369 IF_DROP(&ifp->if_snd); 370 error = ENOBUFS; 371 goto end; 372 } 373 374 gh = mtod(m, struct greip *); 375 if (sc->g_proto == IPPROTO_GRE) { 376 /* we don't have any GRE flags for now */ 377 378 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 379 gh->gi_ptype = htons(etype); 380 } 381 382 gh->gi_pr = sc->g_proto; 383 if (sc->g_proto != IPPROTO_MOBILE) { 384 gh->gi_src = sc->g_src; 385 gh->gi_dst = sc->g_dst; 386 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 387 ((struct ip*)gh)->ip_ttl = GRE_TTL; 388 ((struct ip*)gh)->ip_tos = ip->ip_tos; 389 ((struct ip*)gh)->ip_id = ip->ip_id; 390 gh->gi_len = m->m_pkthdr.len; 391 } 392 393 ifp->if_opackets++; 394 ifp->if_obytes += m->m_pkthdr.len; 395 /* send it off */ 396 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 397 end: 398 sc->called = 0; 399 if (error) 400 ifp->if_oerrors++; 401 return (error); 402 } 403 404 static int 405 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 406 struct rtentry *rt) 407 { 408 int error; 409 410 ifnet_serialize_tx(ifp); 411 error = gre_output_serialized(ifp, m, dst, rt); 412 ifnet_deserialize_tx(ifp); 413 414 return error; 415 } 416 417 static int 418 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 419 { 420 struct ifreq *ifr = (struct ifreq *)data; 421 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 422 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 423 struct gre_softc *sc = ifp->if_softc; 424 struct sockaddr_in si; 425 struct sockaddr *sa = NULL; 426 int error; 427 struct sockaddr_in sp, sm, dp, dm; 428 429 error = 0; 430 431 crit_enter(); 432 switch (cmd) { 433 case SIOCSIFADDR: 434 ifp->if_flags |= IFF_UP; 435 break; 436 case SIOCSIFDSTADDR: 437 break; 438 case SIOCSIFFLAGS: 439 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 440 break; 441 if ((ifr->ifr_flags & IFF_LINK0) != 0) 442 sc->g_proto = IPPROTO_GRE; 443 else 444 sc->g_proto = IPPROTO_MOBILE; 445 goto recompute; 446 case SIOCSIFMTU: 447 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 448 break; 449 if (ifr->ifr_mtu < 576) { 450 error = EINVAL; 451 break; 452 } 453 ifp->if_mtu = ifr->ifr_mtu; 454 break; 455 case SIOCGIFMTU: 456 ifr->ifr_mtu = sc->sc_if.if_mtu; 457 break; 458 case SIOCADDMULTI: 459 case SIOCDELMULTI: 460 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 461 break; 462 if (ifr == NULL) { 463 error = EAFNOSUPPORT; 464 break; 465 } 466 switch (ifr->ifr_addr.sa_family) { 467 #ifdef INET 468 case AF_INET: 469 break; 470 #endif 471 default: 472 error = EAFNOSUPPORT; 473 break; 474 } 475 break; 476 case GRESPROTO: 477 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 478 break; 479 sc->g_proto = ifr->ifr_flags; 480 switch (sc->g_proto) { 481 case IPPROTO_GRE: 482 ifp->if_flags |= IFF_LINK0; 483 break; 484 case IPPROTO_MOBILE: 485 ifp->if_flags &= ~IFF_LINK0; 486 break; 487 default: 488 error = EPROTONOSUPPORT; 489 break; 490 } 491 goto recompute; 492 case GREGPROTO: 493 ifr->ifr_flags = sc->g_proto; 494 break; 495 case GRESADDRS: 496 case GRESADDRD: 497 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 498 break; 499 /* 500 * set tunnel endpoints, compute a less specific route 501 * to the remote end and mark if as up 502 */ 503 sa = &ifr->ifr_addr; 504 if (cmd == GRESADDRS) 505 sc->g_src = (satosin(sa))->sin_addr; 506 if (cmd == GRESADDRD) 507 sc->g_dst = (satosin(sa))->sin_addr; 508 recompute: 509 #ifdef INET 510 if (sc->encap != NULL) { 511 encap_detach(sc->encap); 512 sc->encap = NULL; 513 } 514 #endif 515 if ((sc->g_src.s_addr != INADDR_ANY) && 516 (sc->g_dst.s_addr != INADDR_ANY)) { 517 bzero(&sp, sizeof(sp)); 518 bzero(&sm, sizeof(sm)); 519 bzero(&dp, sizeof(dp)); 520 bzero(&dm, sizeof(dm)); 521 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 522 sizeof(struct sockaddr_in); 523 sp.sin_family = sm.sin_family = dp.sin_family = 524 dm.sin_family = AF_INET; 525 sp.sin_addr = sc->g_src; 526 dp.sin_addr = sc->g_dst; 527 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 528 INADDR_BROADCAST; 529 #ifdef INET 530 sc->encap = encap_attach(AF_INET, sc->g_proto, 531 sintosa(&sp), sintosa(&sm), sintosa(&dp), 532 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 533 &in_gre_protosw : &in_mobile_protosw, sc); 534 if (sc->encap == NULL) 535 kprintf("%s: unable to attach encap\n", 536 if_name(&sc->sc_if)); 537 #endif 538 if (sc->route.ro_rt != 0) /* free old route */ 539 RTFREE(sc->route.ro_rt); 540 if (gre_compute_route(sc) == 0) 541 ifp->if_flags |= IFF_RUNNING; 542 else 543 ifp->if_flags &= ~IFF_RUNNING; 544 } 545 break; 546 case GREGADDRS: 547 memset(&si, 0, sizeof(si)); 548 si.sin_family = AF_INET; 549 si.sin_len = sizeof(struct sockaddr_in); 550 si.sin_addr.s_addr = sc->g_src.s_addr; 551 sa = sintosa(&si); 552 ifr->ifr_addr = *sa; 553 break; 554 case GREGADDRD: 555 memset(&si, 0, sizeof(si)); 556 si.sin_family = AF_INET; 557 si.sin_len = sizeof(struct sockaddr_in); 558 si.sin_addr.s_addr = sc->g_dst.s_addr; 559 sa = sintosa(&si); 560 ifr->ifr_addr = *sa; 561 break; 562 case SIOCSIFPHYADDR: 563 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 564 break; 565 if (aifr->ifra_addr.sin_family != AF_INET || 566 aifr->ifra_dstaddr.sin_family != AF_INET) { 567 error = EAFNOSUPPORT; 568 break; 569 } 570 if (aifr->ifra_addr.sin_len != sizeof(si) || 571 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 572 error = EINVAL; 573 break; 574 } 575 sc->g_src = aifr->ifra_addr.sin_addr; 576 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 577 goto recompute; 578 case SIOCSLIFPHYADDR: 579 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 580 break; 581 if (lifr->addr.ss_family != AF_INET || 582 lifr->dstaddr.ss_family != AF_INET) { 583 error = EAFNOSUPPORT; 584 break; 585 } 586 if (lifr->addr.ss_len != sizeof(si) || 587 lifr->dstaddr.ss_len != sizeof(si)) { 588 error = EINVAL; 589 break; 590 } 591 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 592 sc->g_dst = 593 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 594 goto recompute; 595 case SIOCDIFPHYADDR: 596 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 597 break; 598 sc->g_src.s_addr = INADDR_ANY; 599 sc->g_dst.s_addr = INADDR_ANY; 600 goto recompute; 601 case SIOCGLIFPHYADDR: 602 if (sc->g_src.s_addr == INADDR_ANY || 603 sc->g_dst.s_addr == INADDR_ANY) { 604 error = EADDRNOTAVAIL; 605 break; 606 } 607 memset(&si, 0, sizeof(si)); 608 si.sin_family = AF_INET; 609 si.sin_len = sizeof(struct sockaddr_in); 610 si.sin_addr.s_addr = sc->g_src.s_addr; 611 memcpy(&lifr->addr, &si, sizeof(si)); 612 si.sin_addr.s_addr = sc->g_dst.s_addr; 613 memcpy(&lifr->dstaddr, &si, sizeof(si)); 614 break; 615 case SIOCGIFPSRCADDR: 616 if (sc->g_src.s_addr == INADDR_ANY) { 617 error = EADDRNOTAVAIL; 618 break; 619 } 620 memset(&si, 0, sizeof(si)); 621 si.sin_family = AF_INET; 622 si.sin_len = sizeof(struct sockaddr_in); 623 si.sin_addr.s_addr = sc->g_src.s_addr; 624 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 625 break; 626 case SIOCGIFPDSTADDR: 627 if (sc->g_dst.s_addr == INADDR_ANY) { 628 error = EADDRNOTAVAIL; 629 break; 630 } 631 memset(&si, 0, sizeof(si)); 632 si.sin_family = AF_INET; 633 si.sin_len = sizeof(struct sockaddr_in); 634 si.sin_addr.s_addr = sc->g_dst.s_addr; 635 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 636 break; 637 default: 638 error = EINVAL; 639 break; 640 } 641 642 crit_exit(); 643 return (error); 644 } 645 646 /* 647 * computes a route to our destination that is not the one 648 * which would be taken by ip_output(), as this one will loop back to 649 * us. If the interface is p2p as a--->b, then a routing entry exists 650 * If we now send a packet to b (e.g. ping b), this will come down here 651 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 652 * if_gre. 653 * Goal here is to compute a route to b that is less specific than 654 * a-->b. We know that this one exists as in normal operation we have 655 * at least a default route which matches. 656 */ 657 static int 658 gre_compute_route(struct gre_softc *sc) 659 { 660 struct route *ro; 661 u_int32_t a, b, c; 662 663 ro = &sc->route; 664 665 memset(ro, 0, sizeof(struct route)); 666 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 667 ro->ro_dst.sa_family = AF_INET; 668 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 669 670 /* 671 * toggle last bit, so our interface is not found, but a less 672 * specific route. I'd rather like to specify a shorter mask, 673 * but this is not possible. Should work though. XXX 674 * there is a simpler way ... 675 */ 676 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 677 a = ntohl(sc->g_dst.s_addr); 678 b = a & 0x01; 679 c = a & 0xfffffffe; 680 b = b ^ 0x01; 681 a = b | c; 682 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 683 = htonl(a); 684 } 685 686 #ifdef DIAGNOSTIC 687 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 688 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 689 #endif 690 691 rtalloc(ro); 692 693 /* 694 * check if this returned a route at all and this route is no 695 * recursion to ourself 696 */ 697 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 698 #ifdef DIAGNOSTIC 699 if (ro->ro_rt == NULL) 700 kprintf(" - no route found!\n"); 701 else 702 kprintf(" - route loops back to ourself!\n"); 703 #endif 704 return EADDRNOTAVAIL; 705 } 706 707 /* 708 * now change it back - else ip_output will just drop 709 * the route and search one to this interface ... 710 */ 711 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 712 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 713 714 #ifdef DIAGNOSTIC 715 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 716 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 717 kprintf("\n"); 718 #endif 719 720 return 0; 721 } 722 723 /* 724 * do a checksum of a buffer - much like in_cksum, which operates on 725 * mbufs. 726 */ 727 u_short 728 gre_in_cksum(u_short *p, u_int len) 729 { 730 u_int sum = 0; 731 int nwords = len >> 1; 732 733 while (nwords-- != 0) 734 sum += *p++; 735 736 if (len & 1) { 737 union { 738 u_short w; 739 u_char c[2]; 740 } u; 741 u.c[0] = *(u_char *)p; 742 u.c[1] = 0; 743 sum += u.w; 744 } 745 746 /* end-around-carry */ 747 sum = (sum >> 16) + (sum & 0xffff); 748 sum += (sum >> 16); 749 return (~sum); 750 } 751 752 static int 753 gremodevent(module_t mod, int type, void *data) 754 { 755 756 switch (type) { 757 case MOD_LOAD: 758 greattach(); 759 break; 760 case MOD_UNLOAD: 761 if_clone_detach(&gre_cloner); 762 763 while (!LIST_EMPTY(&gre_softc_list)) 764 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 765 766 break; 767 } 768 return 0; 769 } 770 771 static moduledata_t gre_mod = { 772 "if_gre", 773 gremodevent, 774 0 775 }; 776 777 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 778 MODULE_VERSION(if_gre, 1); 779