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 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 m_freem(m); 318 error = ENOBUFS; 319 goto end; 320 } 321 m0->m_next = m; 322 m->m_data += sizeof(struct ip); 323 m->m_len -= sizeof(struct ip); 324 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 325 m0->m_len = msiz + sizeof(struct ip); 326 m0->m_data += max_linkhdr; 327 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 328 sizeof(struct ip)); 329 m = m0; 330 } else { /* we have some space left in the old one */ 331 m->m_data -= msiz; 332 m->m_len += msiz; 333 m->m_pkthdr.len += msiz; 334 bcopy(ip, mtod(m, caddr_t), 335 sizeof(struct ip)); 336 } 337 ip = mtod(m, struct ip *); 338 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 339 ip->ip_len = ntohs(ip->ip_len) + msiz; 340 } else { /* AF_INET */ 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 m_freem(m); 353 error = EAFNOSUPPORT; 354 goto end; 355 } 356 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 357 } else { 358 m_freem(m); 359 error = EINVAL; 360 goto end; 361 } 362 363 if (m == NULL) { /* impossible */ 364 error = ENOBUFS; 365 goto end; 366 } 367 368 gh = mtod(m, struct greip *); 369 if (sc->g_proto == IPPROTO_GRE) { 370 /* we don't have any GRE flags for now */ 371 372 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 373 gh->gi_ptype = htons(etype); 374 } 375 376 gh->gi_pr = sc->g_proto; 377 if (sc->g_proto != IPPROTO_MOBILE) { 378 gh->gi_src = sc->g_src; 379 gh->gi_dst = sc->g_dst; 380 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 381 ((struct ip*)gh)->ip_ttl = GRE_TTL; 382 ((struct ip*)gh)->ip_tos = ip->ip_tos; 383 ((struct ip*)gh)->ip_id = ip->ip_id; 384 gh->gi_len = m->m_pkthdr.len; 385 } 386 387 IFNET_STAT_INC(ifp, opackets, 1); 388 IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len); 389 /* send it off */ 390 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 391 end: 392 sc->called = 0; 393 if (error) 394 IFNET_STAT_INC(ifp, oerrors, 1); 395 return (error); 396 } 397 398 static int 399 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 400 struct rtentry *rt) 401 { 402 const struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd); 403 int error; 404 405 ifnet_serialize_tx(ifp, ifsq); 406 error = gre_output_serialized(ifp, m, dst, rt); 407 ifnet_deserialize_tx(ifp, ifsq); 408 409 return error; 410 } 411 412 static int 413 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 414 { 415 struct ifreq *ifr = (struct ifreq *)data; 416 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 417 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 418 struct gre_softc *sc = ifp->if_softc; 419 struct sockaddr_in si; 420 struct sockaddr *sa = NULL; 421 int error; 422 struct sockaddr_in sp, sm, dp, dm; 423 424 error = 0; 425 426 crit_enter(); 427 switch (cmd) { 428 case SIOCSIFADDR: 429 ifp->if_flags |= IFF_UP; 430 break; 431 case SIOCSIFDSTADDR: 432 break; 433 case SIOCSIFFLAGS: 434 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 435 break; 436 if ((ifr->ifr_flags & IFF_LINK0) != 0) 437 sc->g_proto = IPPROTO_GRE; 438 else 439 sc->g_proto = IPPROTO_MOBILE; 440 goto recompute; 441 case SIOCSIFMTU: 442 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 443 break; 444 if (ifr->ifr_mtu < 576) { 445 error = EINVAL; 446 break; 447 } 448 ifp->if_mtu = ifr->ifr_mtu; 449 break; 450 case SIOCGIFMTU: 451 ifr->ifr_mtu = sc->sc_if.if_mtu; 452 break; 453 case SIOCADDMULTI: 454 case SIOCDELMULTI: 455 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 456 break; 457 if (ifr == NULL) { 458 error = EAFNOSUPPORT; 459 break; 460 } 461 switch (ifr->ifr_addr.sa_family) { 462 #ifdef INET 463 case AF_INET: 464 break; 465 #endif 466 default: 467 error = EAFNOSUPPORT; 468 break; 469 } 470 break; 471 case GRESPROTO: 472 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 473 break; 474 sc->g_proto = ifr->ifr_flags; 475 switch (sc->g_proto) { 476 case IPPROTO_GRE: 477 ifp->if_flags |= IFF_LINK0; 478 break; 479 case IPPROTO_MOBILE: 480 ifp->if_flags &= ~IFF_LINK0; 481 break; 482 default: 483 error = EPROTONOSUPPORT; 484 break; 485 } 486 goto recompute; 487 case GREGPROTO: 488 ifr->ifr_flags = sc->g_proto; 489 break; 490 case GRESADDRS: 491 case GRESADDRD: 492 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 493 break; 494 /* 495 * set tunnel endpoints, compute a less specific route 496 * to the remote end and mark if as up 497 */ 498 sa = &ifr->ifr_addr; 499 if (cmd == GRESADDRS) 500 sc->g_src = (satosin(sa))->sin_addr; 501 if (cmd == GRESADDRD) 502 sc->g_dst = (satosin(sa))->sin_addr; 503 recompute: 504 #ifdef INET 505 if (sc->encap != NULL) { 506 encap_detach(sc->encap); 507 sc->encap = NULL; 508 } 509 #endif 510 if ((sc->g_src.s_addr != INADDR_ANY) && 511 (sc->g_dst.s_addr != INADDR_ANY)) { 512 bzero(&sp, sizeof(sp)); 513 bzero(&sm, sizeof(sm)); 514 bzero(&dp, sizeof(dp)); 515 bzero(&dm, sizeof(dm)); 516 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 517 sizeof(struct sockaddr_in); 518 sp.sin_family = sm.sin_family = dp.sin_family = 519 dm.sin_family = AF_INET; 520 sp.sin_addr = sc->g_src; 521 dp.sin_addr = sc->g_dst; 522 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 523 INADDR_BROADCAST; 524 #ifdef INET 525 sc->encap = encap_attach(AF_INET, sc->g_proto, 526 sintosa(&sp), sintosa(&sm), sintosa(&dp), 527 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 528 &in_gre_protosw : &in_mobile_protosw, sc); 529 if (sc->encap == NULL) 530 kprintf("%s: unable to attach encap\n", 531 if_name(&sc->sc_if)); 532 #endif 533 if (sc->route.ro_rt != 0) /* free old route */ 534 RTFREE(sc->route.ro_rt); 535 if (gre_compute_route(sc) == 0) 536 ifp->if_flags |= IFF_RUNNING; 537 else 538 ifp->if_flags &= ~IFF_RUNNING; 539 } 540 break; 541 case GREGADDRS: 542 memset(&si, 0, sizeof(si)); 543 si.sin_family = AF_INET; 544 si.sin_len = sizeof(struct sockaddr_in); 545 si.sin_addr.s_addr = sc->g_src.s_addr; 546 sa = sintosa(&si); 547 ifr->ifr_addr = *sa; 548 break; 549 case GREGADDRD: 550 memset(&si, 0, sizeof(si)); 551 si.sin_family = AF_INET; 552 si.sin_len = sizeof(struct sockaddr_in); 553 si.sin_addr.s_addr = sc->g_dst.s_addr; 554 sa = sintosa(&si); 555 ifr->ifr_addr = *sa; 556 break; 557 case SIOCSIFPHYADDR: 558 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 559 break; 560 if (aifr->ifra_addr.sin_family != AF_INET || 561 aifr->ifra_dstaddr.sin_family != AF_INET) { 562 error = EAFNOSUPPORT; 563 break; 564 } 565 if (aifr->ifra_addr.sin_len != sizeof(si) || 566 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 567 error = EINVAL; 568 break; 569 } 570 sc->g_src = aifr->ifra_addr.sin_addr; 571 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 572 goto recompute; 573 case SIOCSLIFPHYADDR: 574 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 575 break; 576 if (lifr->addr.ss_family != AF_INET || 577 lifr->dstaddr.ss_family != AF_INET) { 578 error = EAFNOSUPPORT; 579 break; 580 } 581 if (lifr->addr.ss_len != sizeof(si) || 582 lifr->dstaddr.ss_len != sizeof(si)) { 583 error = EINVAL; 584 break; 585 } 586 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 587 sc->g_dst = 588 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 589 goto recompute; 590 case SIOCDIFPHYADDR: 591 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 592 break; 593 sc->g_src.s_addr = INADDR_ANY; 594 sc->g_dst.s_addr = INADDR_ANY; 595 goto recompute; 596 case SIOCGLIFPHYADDR: 597 if (sc->g_src.s_addr == INADDR_ANY || 598 sc->g_dst.s_addr == INADDR_ANY) { 599 error = EADDRNOTAVAIL; 600 break; 601 } 602 memset(&si, 0, sizeof(si)); 603 si.sin_family = AF_INET; 604 si.sin_len = sizeof(struct sockaddr_in); 605 si.sin_addr.s_addr = sc->g_src.s_addr; 606 memcpy(&lifr->addr, &si, sizeof(si)); 607 si.sin_addr.s_addr = sc->g_dst.s_addr; 608 memcpy(&lifr->dstaddr, &si, sizeof(si)); 609 break; 610 case SIOCGIFPSRCADDR: 611 if (sc->g_src.s_addr == INADDR_ANY) { 612 error = EADDRNOTAVAIL; 613 break; 614 } 615 memset(&si, 0, sizeof(si)); 616 si.sin_family = AF_INET; 617 si.sin_len = sizeof(struct sockaddr_in); 618 si.sin_addr.s_addr = sc->g_src.s_addr; 619 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 620 break; 621 case SIOCGIFPDSTADDR: 622 if (sc->g_dst.s_addr == INADDR_ANY) { 623 error = EADDRNOTAVAIL; 624 break; 625 } 626 memset(&si, 0, sizeof(si)); 627 si.sin_family = AF_INET; 628 si.sin_len = sizeof(struct sockaddr_in); 629 si.sin_addr.s_addr = sc->g_dst.s_addr; 630 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 631 break; 632 default: 633 error = EINVAL; 634 break; 635 } 636 637 crit_exit(); 638 return (error); 639 } 640 641 /* 642 * computes a route to our destination that is not the one 643 * which would be taken by ip_output(), as this one will loop back to 644 * us. If the interface is p2p as a--->b, then a routing entry exists 645 * If we now send a packet to b (e.g. ping b), this will come down here 646 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 647 * if_gre. 648 * Goal here is to compute a route to b that is less specific than 649 * a-->b. We know that this one exists as in normal operation we have 650 * at least a default route which matches. 651 */ 652 static int 653 gre_compute_route(struct gre_softc *sc) 654 { 655 struct route *ro; 656 u_int32_t a, b, c; 657 658 ro = &sc->route; 659 660 memset(ro, 0, sizeof(struct route)); 661 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 662 ro->ro_dst.sa_family = AF_INET; 663 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 664 665 /* 666 * toggle last bit, so our interface is not found, but a less 667 * specific route. I'd rather like to specify a shorter mask, 668 * but this is not possible. Should work though. XXX 669 * there is a simpler way ... 670 */ 671 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 672 a = ntohl(sc->g_dst.s_addr); 673 b = a & 0x01; 674 c = a & 0xfffffffe; 675 b = b ^ 0x01; 676 a = b | c; 677 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 678 = htonl(a); 679 } 680 681 #ifdef DIAGNOSTIC 682 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 683 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 684 #endif 685 686 rtalloc(ro); 687 688 /* 689 * check if this returned a route at all and this route is no 690 * recursion to ourself 691 */ 692 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 693 #ifdef DIAGNOSTIC 694 if (ro->ro_rt == NULL) 695 kprintf(" - no route found!\n"); 696 else 697 kprintf(" - route loops back to ourself!\n"); 698 #endif 699 return EADDRNOTAVAIL; 700 } 701 702 /* 703 * now change it back - else ip_output will just drop 704 * the route and search one to this interface ... 705 */ 706 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 707 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 708 709 #ifdef DIAGNOSTIC 710 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 711 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 712 kprintf("\n"); 713 #endif 714 715 return 0; 716 } 717 718 /* 719 * do a checksum of a buffer - much like in_cksum, which operates on 720 * mbufs. 721 */ 722 u_short 723 gre_in_cksum(u_short *p, u_int len) 724 { 725 u_int sum = 0; 726 int nwords = len >> 1; 727 728 while (nwords-- != 0) 729 sum += *p++; 730 731 if (len & 1) { 732 union { 733 u_short w; 734 u_char c[2]; 735 } u; 736 u.c[0] = *(u_char *)p; 737 u.c[1] = 0; 738 sum += u.w; 739 } 740 741 /* end-around-carry */ 742 sum = (sum >> 16) + (sum & 0xffff); 743 sum += (sum >> 16); 744 return (~sum); 745 } 746 747 static int 748 gremodevent(module_t mod, int type, void *data) 749 { 750 751 switch (type) { 752 case MOD_LOAD: 753 greattach(); 754 break; 755 case MOD_UNLOAD: 756 if_clone_detach(&gre_cloner); 757 758 while (!LIST_EMPTY(&gre_softc_list)) 759 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 760 761 break; 762 } 763 return 0; 764 } 765 766 static moduledata_t gre_mod = { 767 "if_gre", 768 gremodevent, 769 0 770 }; 771 772 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 773 MODULE_VERSION(if_gre, 1); 774