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_char osrc; 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 osrc = 0; 264 265 if (ifp->if_bpf) { 266 uint32_t af = dst->sa_family; 267 268 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 269 } 270 271 m->m_flags &= ~(M_BCAST|M_MCAST); 272 273 if (sc->g_proto == IPPROTO_MOBILE) { 274 if (dst->sa_family == AF_INET) { 275 struct mbuf *m0; 276 int msiz; 277 278 ip = mtod(m, struct ip *); 279 280 /* 281 * RFC2004 specifies that fragmented datagrams shouldn't 282 * be encapsulated. 283 */ 284 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 285 IF_DROP(&ifp->if_snd); 286 m_freem(m); 287 error = EINVAL; /* is there better errno? */ 288 goto end; 289 } 290 memset(&mob_h, 0, MOB_H_SIZ_L); 291 mob_h.proto = (ip->ip_p) << 8; 292 mob_h.odst = ip->ip_dst.s_addr; 293 ip->ip_dst.s_addr = sc->g_dst.s_addr; 294 295 /* 296 * If the packet comes from our host, we only change 297 * the destination address in the IP header. 298 * Else we also need to save and change the source 299 */ 300 if (in_hosteq(ip->ip_src, sc->g_src)) { 301 msiz = MOB_H_SIZ_S; 302 } else { 303 mob_h.proto |= MOB_H_SBIT; 304 mob_h.osrc = ip->ip_src.s_addr; 305 ip->ip_src.s_addr = sc->g_src.s_addr; 306 msiz = MOB_H_SIZ_L; 307 } 308 mob_h.proto = htons(mob_h.proto); 309 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 310 311 if ((m->m_data - msiz) < m->m_pktdat) { 312 /* need new mbuf */ 313 MGETHDR(m0, MB_DONTWAIT, MT_HEADER); 314 if (m0 == NULL) { 315 IF_DROP(&ifp->if_snd); 316 m_freem(m); 317 error = ENOBUFS; 318 goto end; 319 } 320 m0->m_next = m; 321 m->m_data += sizeof(struct ip); 322 m->m_len -= sizeof(struct ip); 323 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 324 m0->m_len = msiz + sizeof(struct ip); 325 m0->m_data += max_linkhdr; 326 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 327 sizeof(struct ip)); 328 m = m0; 329 } else { /* we have some space left in the old one */ 330 m->m_data -= msiz; 331 m->m_len += msiz; 332 m->m_pkthdr.len += msiz; 333 bcopy(ip, mtod(m, caddr_t), 334 sizeof(struct ip)); 335 } 336 ip = mtod(m, struct ip *); 337 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 338 ip->ip_len = ntohs(ip->ip_len) + msiz; 339 } else { /* AF_INET */ 340 IF_DROP(&ifp->if_snd); 341 m_freem(m); 342 error = EINVAL; 343 goto end; 344 } 345 } else if (sc->g_proto == IPPROTO_GRE) { 346 switch (dst->sa_family) { 347 case AF_INET: 348 ip = mtod(m, struct ip *); 349 etype = ETHERTYPE_IP; 350 break; 351 default: 352 IF_DROP(&ifp->if_snd); 353 m_freem(m); 354 error = EAFNOSUPPORT; 355 goto end; 356 } 357 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 358 } else { 359 IF_DROP(&ifp->if_snd); 360 m_freem(m); 361 error = EINVAL; 362 goto end; 363 } 364 365 if (m == NULL) { /* impossible */ 366 IF_DROP(&ifp->if_snd); 367 error = ENOBUFS; 368 goto end; 369 } 370 371 gh = mtod(m, struct greip *); 372 if (sc->g_proto == IPPROTO_GRE) { 373 /* we don't have any GRE flags for now */ 374 375 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 376 gh->gi_ptype = htons(etype); 377 } 378 379 gh->gi_pr = sc->g_proto; 380 if (sc->g_proto != IPPROTO_MOBILE) { 381 gh->gi_src = sc->g_src; 382 gh->gi_dst = sc->g_dst; 383 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 384 ((struct ip*)gh)->ip_ttl = GRE_TTL; 385 ((struct ip*)gh)->ip_tos = ip->ip_tos; 386 ((struct ip*)gh)->ip_id = ip->ip_id; 387 gh->gi_len = m->m_pkthdr.len; 388 } 389 390 ifp->if_opackets++; 391 ifp->if_obytes += m->m_pkthdr.len; 392 /* send it off */ 393 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 394 end: 395 sc->called = 0; 396 if (error) 397 ifp->if_oerrors++; 398 return (error); 399 } 400 401 static int 402 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 403 struct rtentry *rt) 404 { 405 int error; 406 407 ifnet_serialize_tx(ifp); 408 error = gre_output_serialized(ifp, m, dst, rt); 409 ifnet_deserialize_tx(ifp); 410 411 return error; 412 } 413 414 static int 415 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 416 { 417 struct ifreq *ifr = (struct ifreq *)data; 418 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 419 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 420 struct gre_softc *sc = ifp->if_softc; 421 struct sockaddr_in si; 422 struct sockaddr *sa = NULL; 423 int error; 424 struct sockaddr_in sp, sm, dp, dm; 425 426 error = 0; 427 428 crit_enter(); 429 switch (cmd) { 430 case SIOCSIFADDR: 431 ifp->if_flags |= IFF_UP; 432 break; 433 case SIOCSIFDSTADDR: 434 break; 435 case SIOCSIFFLAGS: 436 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 437 break; 438 if ((ifr->ifr_flags & IFF_LINK0) != 0) 439 sc->g_proto = IPPROTO_GRE; 440 else 441 sc->g_proto = IPPROTO_MOBILE; 442 goto recompute; 443 case SIOCSIFMTU: 444 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 445 break; 446 if (ifr->ifr_mtu < 576) { 447 error = EINVAL; 448 break; 449 } 450 ifp->if_mtu = ifr->ifr_mtu; 451 break; 452 case SIOCGIFMTU: 453 ifr->ifr_mtu = sc->sc_if.if_mtu; 454 break; 455 case SIOCADDMULTI: 456 case SIOCDELMULTI: 457 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 458 break; 459 if (ifr == NULL) { 460 error = EAFNOSUPPORT; 461 break; 462 } 463 switch (ifr->ifr_addr.sa_family) { 464 #ifdef INET 465 case AF_INET: 466 break; 467 #endif 468 default: 469 error = EAFNOSUPPORT; 470 break; 471 } 472 break; 473 case GRESPROTO: 474 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 475 break; 476 sc->g_proto = ifr->ifr_flags; 477 switch (sc->g_proto) { 478 case IPPROTO_GRE: 479 ifp->if_flags |= IFF_LINK0; 480 break; 481 case IPPROTO_MOBILE: 482 ifp->if_flags &= ~IFF_LINK0; 483 break; 484 default: 485 error = EPROTONOSUPPORT; 486 break; 487 } 488 goto recompute; 489 case GREGPROTO: 490 ifr->ifr_flags = sc->g_proto; 491 break; 492 case GRESADDRS: 493 case GRESADDRD: 494 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 495 break; 496 /* 497 * set tunnel endpoints, compute a less specific route 498 * to the remote end and mark if as up 499 */ 500 sa = &ifr->ifr_addr; 501 if (cmd == GRESADDRS) 502 sc->g_src = (satosin(sa))->sin_addr; 503 if (cmd == GRESADDRD) 504 sc->g_dst = (satosin(sa))->sin_addr; 505 recompute: 506 #ifdef INET 507 if (sc->encap != NULL) { 508 encap_detach(sc->encap); 509 sc->encap = NULL; 510 } 511 #endif 512 if ((sc->g_src.s_addr != INADDR_ANY) && 513 (sc->g_dst.s_addr != INADDR_ANY)) { 514 bzero(&sp, sizeof(sp)); 515 bzero(&sm, sizeof(sm)); 516 bzero(&dp, sizeof(dp)); 517 bzero(&dm, sizeof(dm)); 518 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 519 sizeof(struct sockaddr_in); 520 sp.sin_family = sm.sin_family = dp.sin_family = 521 dm.sin_family = AF_INET; 522 sp.sin_addr = sc->g_src; 523 dp.sin_addr = sc->g_dst; 524 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 525 INADDR_BROADCAST; 526 #ifdef INET 527 sc->encap = encap_attach(AF_INET, sc->g_proto, 528 sintosa(&sp), sintosa(&sm), sintosa(&dp), 529 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 530 &in_gre_protosw : &in_mobile_protosw, sc); 531 if (sc->encap == NULL) 532 kprintf("%s: unable to attach encap\n", 533 if_name(&sc->sc_if)); 534 #endif 535 if (sc->route.ro_rt != 0) /* free old route */ 536 RTFREE(sc->route.ro_rt); 537 if (gre_compute_route(sc) == 0) 538 ifp->if_flags |= IFF_RUNNING; 539 else 540 ifp->if_flags &= ~IFF_RUNNING; 541 } 542 break; 543 case GREGADDRS: 544 memset(&si, 0, sizeof(si)); 545 si.sin_family = AF_INET; 546 si.sin_len = sizeof(struct sockaddr_in); 547 si.sin_addr.s_addr = sc->g_src.s_addr; 548 sa = sintosa(&si); 549 ifr->ifr_addr = *sa; 550 break; 551 case GREGADDRD: 552 memset(&si, 0, sizeof(si)); 553 si.sin_family = AF_INET; 554 si.sin_len = sizeof(struct sockaddr_in); 555 si.sin_addr.s_addr = sc->g_dst.s_addr; 556 sa = sintosa(&si); 557 ifr->ifr_addr = *sa; 558 break; 559 case SIOCSIFPHYADDR: 560 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 561 break; 562 if (aifr->ifra_addr.sin_family != AF_INET || 563 aifr->ifra_dstaddr.sin_family != AF_INET) { 564 error = EAFNOSUPPORT; 565 break; 566 } 567 if (aifr->ifra_addr.sin_len != sizeof(si) || 568 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 569 error = EINVAL; 570 break; 571 } 572 sc->g_src = aifr->ifra_addr.sin_addr; 573 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 574 goto recompute; 575 case SIOCSLIFPHYADDR: 576 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 577 break; 578 if (lifr->addr.ss_family != AF_INET || 579 lifr->dstaddr.ss_family != AF_INET) { 580 error = EAFNOSUPPORT; 581 break; 582 } 583 if (lifr->addr.ss_len != sizeof(si) || 584 lifr->dstaddr.ss_len != sizeof(si)) { 585 error = EINVAL; 586 break; 587 } 588 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 589 sc->g_dst = 590 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 591 goto recompute; 592 case SIOCDIFPHYADDR: 593 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 594 break; 595 sc->g_src.s_addr = INADDR_ANY; 596 sc->g_dst.s_addr = INADDR_ANY; 597 goto recompute; 598 case SIOCGLIFPHYADDR: 599 if (sc->g_src.s_addr == INADDR_ANY || 600 sc->g_dst.s_addr == INADDR_ANY) { 601 error = EADDRNOTAVAIL; 602 break; 603 } 604 memset(&si, 0, sizeof(si)); 605 si.sin_family = AF_INET; 606 si.sin_len = sizeof(struct sockaddr_in); 607 si.sin_addr.s_addr = sc->g_src.s_addr; 608 memcpy(&lifr->addr, &si, sizeof(si)); 609 si.sin_addr.s_addr = sc->g_dst.s_addr; 610 memcpy(&lifr->dstaddr, &si, sizeof(si)); 611 break; 612 case SIOCGIFPSRCADDR: 613 if (sc->g_src.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 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 622 break; 623 case SIOCGIFPDSTADDR: 624 if (sc->g_dst.s_addr == INADDR_ANY) { 625 error = EADDRNOTAVAIL; 626 break; 627 } 628 memset(&si, 0, sizeof(si)); 629 si.sin_family = AF_INET; 630 si.sin_len = sizeof(struct sockaddr_in); 631 si.sin_addr.s_addr = sc->g_dst.s_addr; 632 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 633 break; 634 default: 635 error = EINVAL; 636 break; 637 } 638 639 crit_exit(); 640 return (error); 641 } 642 643 /* 644 * computes a route to our destination that is not the one 645 * which would be taken by ip_output(), as this one will loop back to 646 * us. If the interface is p2p as a--->b, then a routing entry exists 647 * If we now send a packet to b (e.g. ping b), this will come down here 648 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 649 * if_gre. 650 * Goal here is to compute a route to b that is less specific than 651 * a-->b. We know that this one exists as in normal operation we have 652 * at least a default route which matches. 653 */ 654 static int 655 gre_compute_route(struct gre_softc *sc) 656 { 657 struct route *ro; 658 u_int32_t a, b, c; 659 660 ro = &sc->route; 661 662 memset(ro, 0, sizeof(struct route)); 663 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 664 ro->ro_dst.sa_family = AF_INET; 665 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 666 667 /* 668 * toggle last bit, so our interface is not found, but a less 669 * specific route. I'd rather like to specify a shorter mask, 670 * but this is not possible. Should work though. XXX 671 * there is a simpler way ... 672 */ 673 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 674 a = ntohl(sc->g_dst.s_addr); 675 b = a & 0x01; 676 c = a & 0xfffffffe; 677 b = b ^ 0x01; 678 a = b | c; 679 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 680 = htonl(a); 681 } 682 683 #ifdef DIAGNOSTIC 684 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 685 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 686 #endif 687 688 rtalloc(ro); 689 690 /* 691 * check if this returned a route at all and this route is no 692 * recursion to ourself 693 */ 694 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 695 #ifdef DIAGNOSTIC 696 if (ro->ro_rt == NULL) 697 kprintf(" - no route found!\n"); 698 else 699 kprintf(" - route loops back to ourself!\n"); 700 #endif 701 return EADDRNOTAVAIL; 702 } 703 704 /* 705 * now change it back - else ip_output will just drop 706 * the route and search one to this interface ... 707 */ 708 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 709 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 710 711 #ifdef DIAGNOSTIC 712 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 713 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 714 kprintf("\n"); 715 #endif 716 717 return 0; 718 } 719 720 /* 721 * do a checksum of a buffer - much like in_cksum, which operates on 722 * mbufs. 723 */ 724 u_short 725 gre_in_cksum(u_short *p, u_int len) 726 { 727 u_int sum = 0; 728 int nwords = len >> 1; 729 730 while (nwords-- != 0) 731 sum += *p++; 732 733 if (len & 1) { 734 union { 735 u_short w; 736 u_char c[2]; 737 } u; 738 u.c[0] = *(u_char *)p; 739 u.c[1] = 0; 740 sum += u.w; 741 } 742 743 /* end-around-carry */ 744 sum = (sum >> 16) + (sum & 0xffff); 745 sum += (sum >> 16); 746 return (~sum); 747 } 748 749 static int 750 gremodevent(module_t mod, int type, void *data) 751 { 752 753 switch (type) { 754 case MOD_LOAD: 755 greattach(); 756 break; 757 case MOD_UNLOAD: 758 if_clone_detach(&gre_cloner); 759 760 while (!LIST_EMPTY(&gre_softc_list)) 761 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 762 763 break; 764 } 765 return 0; 766 } 767 768 static moduledata_t gre_mod = { 769 "if_gre", 770 gremodevent, 771 0 772 }; 773 774 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 775 MODULE_VERSION(if_gre, 1); 776