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 1.5 2003/08/07 21:17:24 dillon 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/malloc.h> 57 #include <sys/mbuf.h> 58 #include <sys/proc.h> 59 #include <sys/protosw.h> 60 #include <machine/bus.h> 61 #include <sys/rman.h> 62 #include <sys/socket.h> 63 #include <sys/sockio.h> 64 #include <sys/sysctl.h> 65 #include <sys/systm.h> 66 67 #include <net/ethernet.h> 68 #include <net/if.h> 69 #include <net/if_types.h> 70 #include <net/route.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 #define GRE_MAXUNIT 0x7fff 98 99 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 100 static struct rman greunits[1]; 101 102 struct gre_softc_head gre_softc_list; 103 104 static int gre_clone_create(struct if_clone *, int *); 105 static void gre_clone_destroy(struct ifnet *); 106 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 107 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 108 struct rtentry *rt); 109 110 static struct if_clone gre_cloner = 111 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 112 113 static int gre_compute_route(struct gre_softc *sc); 114 115 static void greattach(void); 116 117 #ifdef INET 118 extern struct domain inetdomain; 119 static const struct protosw in_gre_protosw = 120 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 121 gre_input, rip_output, rip_ctlinput, rip_ctloutput, 122 0, 123 0, 0, 0, 0, 124 &rip_usrreqs 125 }; 126 static const struct protosw in_mobile_protosw = 127 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 128 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput, 129 0, 130 0, 0, 0, 0, 131 &rip_usrreqs 132 }; 133 #endif 134 135 SYSCTL_DECL(_net_link); 136 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 137 "Generic Routing Encapsulation"); 138 #ifndef MAX_GRE_NEST 139 /* 140 * This macro controls the default upper limitation on nesting of gre tunnels. 141 * Since, setting a large value to this macro with a careless configuration 142 * may introduce system crash, we don't allow any nestings by default. 143 * If you need to configure nested gre tunnels, you can define this macro 144 * in your kernel configuration file. However, if you do so, please be 145 * careful to configure the tunnels so that it won't make a loop. 146 */ 147 #define MAX_GRE_NEST 1 148 #endif 149 static int max_gre_nesting = MAX_GRE_NEST; 150 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 151 &max_gre_nesting, 0, "Max nested tunnels"); 152 153 /* ARGSUSED */ 154 static void 155 greattach(void) 156 { 157 158 LIST_INIT(&gre_softc_list); 159 if_clone_attach(&gre_cloner); 160 } 161 162 static int 163 gre_clone_create(ifc, unit) 164 struct if_clone *ifc; 165 int *unit; 166 { 167 struct resource *r; 168 struct gre_softc *sc; 169 170 if (*unit > GRE_MAXUNIT) 171 return (ENXIO); 172 173 if (*unit < 0) { 174 r = rman_reserve_resource(greunits, 0, GRE_MAXUNIT, 1, 175 RF_ALLOCATED | RF_ACTIVE, NULL); 176 if (r == NULL) 177 return (ENOSPC); 178 *unit = rman_get_start(r); 179 } else { 180 r = rman_reserve_resource(greunits, *unit, *unit, 1, 181 RF_ALLOCATED | RF_ACTIVE, NULL); 182 if (r == NULL) 183 return (EEXIST); 184 } 185 186 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 187 memset(sc, 0, sizeof(struct gre_softc)); 188 189 sc->sc_if.if_name = GRENAME; 190 sc->sc_if.if_softc = sc; 191 sc->sc_if.if_unit = *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 sc->r_unit = r; 206 if_attach(&sc->sc_if); 207 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 208 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 209 return (0); 210 } 211 212 static void 213 gre_clone_destroy(ifp) 214 struct ifnet *ifp; 215 { 216 int err; 217 struct gre_softc *sc = ifp->if_softc; 218 219 #ifdef INET 220 if (sc->encap != NULL) 221 encap_detach(sc->encap); 222 #endif 223 LIST_REMOVE(sc, sc_list); 224 bpfdetach(ifp); 225 if_detach(ifp); 226 227 err = rman_release_resource(sc->r_unit); 228 KASSERT(err == 0, ("Unexpected error freeing resource")); 229 230 free(sc, M_GRE); 231 } 232 233 /* 234 * The output routine. Takes a packet and encapsulates it in the protocol 235 * given by sc->g_proto. See also RFC 1701 and RFC 2004 236 */ 237 static int 238 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 239 struct rtentry *rt) 240 { 241 int error = 0; 242 struct gre_softc *sc = ifp->if_softc; 243 struct greip *gh; 244 struct ip *ip; 245 u_char osrc; 246 u_short etype = 0; 247 struct mobile_h mob_h; 248 249 /* 250 * gre may cause infinite recursion calls when misconfigured. 251 * We'll prevent this by introducing upper limit. 252 */ 253 if (++(sc->called) > max_gre_nesting) { 254 printf("%s: gre_output: recursively called too many " 255 "times(%d)\n", if_name(&sc->sc_if), sc->called); 256 m_freem(m); 257 error = EIO; /* is there better errno? */ 258 goto end; 259 } 260 261 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 262 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 263 m_freem(m); 264 error = ENETDOWN; 265 goto end; 266 } 267 268 gh = NULL; 269 ip = NULL; 270 osrc = 0; 271 272 if (ifp->if_bpf) { 273 /* see comment of other if_foo.c files */ 274 struct mbuf m0; 275 u_int32_t af = dst->sa_family; 276 277 m0.m_next = m; 278 m0.m_len = 4; 279 m0.m_data = (char *)⁡ 280 281 bpf_mtap(ifp, &m0); 282 } 283 284 m->m_flags &= ~(M_BCAST|M_MCAST); 285 286 if (sc->g_proto == IPPROTO_MOBILE) { 287 if (dst->sa_family == AF_INET) { 288 struct mbuf *m0; 289 int msiz; 290 291 ip = mtod(m, struct ip *); 292 293 /* 294 * RFC2004 specifies that fragmented diagrams shouldn't 295 * be encapsulated. 296 */ 297 if ((ip->ip_off & IP_MF) != 0) { 298 IF_DROP(&ifp->if_snd); 299 m_freem(m); 300 error = EINVAL; /* is there better errno? */ 301 goto end; 302 } 303 memset(&mob_h, 0, MOB_H_SIZ_L); 304 mob_h.proto = (ip->ip_p) << 8; 305 mob_h.odst = ip->ip_dst.s_addr; 306 ip->ip_dst.s_addr = sc->g_dst.s_addr; 307 308 /* 309 * If the packet comes from our host, we only change 310 * the destination address in the IP header. 311 * Else we also need to save and change the source 312 */ 313 if (in_hosteq(ip->ip_src, sc->g_src)) { 314 msiz = MOB_H_SIZ_S; 315 } else { 316 mob_h.proto |= MOB_H_SBIT; 317 mob_h.osrc = ip->ip_src.s_addr; 318 ip->ip_src.s_addr = sc->g_src.s_addr; 319 msiz = MOB_H_SIZ_L; 320 } 321 mob_h.proto = htons(mob_h.proto); 322 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 323 324 if ((m->m_data - msiz) < m->m_pktdat) { 325 /* need new mbuf */ 326 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 327 if (m0 == NULL) { 328 IF_DROP(&ifp->if_snd); 329 m_freem(m); 330 error = ENOBUFS; 331 goto end; 332 } 333 m0->m_next = m; 334 m->m_data += sizeof(struct ip); 335 m->m_len -= sizeof(struct ip); 336 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 337 m0->m_len = msiz + sizeof(struct ip); 338 m0->m_data += max_linkhdr; 339 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 340 sizeof(struct ip)); 341 m = m0; 342 } else { /* we have some space left in the old one */ 343 m->m_data -= msiz; 344 m->m_len += msiz; 345 m->m_pkthdr.len += msiz; 346 bcopy(ip, mtod(m, caddr_t), 347 sizeof(struct ip)); 348 } 349 ip = mtod(m, struct ip *); 350 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 351 ip->ip_len = ntohs(ip->ip_len) + msiz; 352 } else { /* AF_INET */ 353 IF_DROP(&ifp->if_snd); 354 m_freem(m); 355 error = EINVAL; 356 goto end; 357 } 358 } else if (sc->g_proto == IPPROTO_GRE) { 359 switch (dst->sa_family) { 360 case AF_INET: 361 ip = mtod(m, struct ip *); 362 etype = ETHERTYPE_IP; 363 break; 364 #ifdef NETATALK 365 case AF_APPLETALK: 366 etype = ETHERTYPE_ATALK; 367 break; 368 #endif 369 #ifdef NS 370 case AF_NS: 371 etype = ETHERTYPE_NS; 372 break; 373 #endif 374 default: 375 IF_DROP(&ifp->if_snd); 376 m_freem(m); 377 error = EAFNOSUPPORT; 378 goto end; 379 } 380 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 381 } else { 382 IF_DROP(&ifp->if_snd); 383 m_freem(m); 384 error = EINVAL; 385 goto end; 386 } 387 388 if (m == NULL) { /* impossible */ 389 IF_DROP(&ifp->if_snd); 390 error = ENOBUFS; 391 goto end; 392 } 393 394 gh = mtod(m, struct greip *); 395 if (sc->g_proto == IPPROTO_GRE) { 396 /* we don't have any GRE flags for now */ 397 398 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 399 gh->gi_ptype = htons(etype); 400 } 401 402 gh->gi_pr = sc->g_proto; 403 if (sc->g_proto != IPPROTO_MOBILE) { 404 gh->gi_src = sc->g_src; 405 gh->gi_dst = sc->g_dst; 406 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 407 ((struct ip*)gh)->ip_ttl = GRE_TTL; 408 ((struct ip*)gh)->ip_tos = ip->ip_tos; 409 ((struct ip*)gh)->ip_id = ip->ip_id; 410 gh->gi_len = m->m_pkthdr.len; 411 } 412 413 ifp->if_opackets++; 414 ifp->if_obytes += m->m_pkthdr.len; 415 /* send it off */ 416 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 417 end: 418 sc->called = 0; 419 if (error) 420 ifp->if_oerrors++; 421 return (error); 422 } 423 424 static int 425 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 426 { 427 struct ifreq *ifr = (struct ifreq *)data; 428 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 429 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 430 struct gre_softc *sc = ifp->if_softc; 431 int s; 432 struct sockaddr_in si; 433 struct sockaddr *sa = NULL; 434 int error; 435 struct sockaddr_in sp, sm, dp, dm; 436 struct thread *td = curthread; 437 438 error = 0; 439 440 s = splnet(); 441 switch (cmd) { 442 case SIOCSIFADDR: 443 ifp->if_flags |= IFF_UP; 444 break; 445 case SIOCSIFDSTADDR: 446 break; 447 case SIOCSIFFLAGS: 448 if ((error = suser(td)) != 0) 449 break; 450 if ((ifr->ifr_flags & IFF_LINK0) != 0) 451 sc->g_proto = IPPROTO_GRE; 452 else 453 sc->g_proto = IPPROTO_MOBILE; 454 goto recompute; 455 case SIOCSIFMTU: 456 if ((error = suser(td)) != 0) 457 break; 458 if (ifr->ifr_mtu < 576) { 459 error = EINVAL; 460 break; 461 } 462 ifp->if_mtu = ifr->ifr_mtu; 463 break; 464 case SIOCGIFMTU: 465 ifr->ifr_mtu = sc->sc_if.if_mtu; 466 break; 467 case SIOCADDMULTI: 468 case SIOCDELMULTI: 469 if ((error = suser(td)) != 0) 470 break; 471 if (ifr == 0) { 472 error = EAFNOSUPPORT; 473 break; 474 } 475 switch (ifr->ifr_addr.sa_family) { 476 #ifdef INET 477 case AF_INET: 478 break; 479 #endif 480 default: 481 error = EAFNOSUPPORT; 482 break; 483 } 484 break; 485 case GRESPROTO: 486 if ((error = suser(td)) != 0) 487 break; 488 sc->g_proto = ifr->ifr_flags; 489 switch (sc->g_proto) { 490 case IPPROTO_GRE: 491 ifp->if_flags |= IFF_LINK0; 492 break; 493 case IPPROTO_MOBILE: 494 ifp->if_flags &= ~IFF_LINK0; 495 break; 496 default: 497 error = EPROTONOSUPPORT; 498 break; 499 } 500 goto recompute; 501 case GREGPROTO: 502 ifr->ifr_flags = sc->g_proto; 503 break; 504 case GRESADDRS: 505 case GRESADDRD: 506 if ((error = suser(td)) != 0) 507 break; 508 /* 509 * set tunnel endpoints, compute a less specific route 510 * to the remote end and mark if as up 511 */ 512 sa = &ifr->ifr_addr; 513 if (cmd == GRESADDRS) 514 sc->g_src = (satosin(sa))->sin_addr; 515 if (cmd == GRESADDRD) 516 sc->g_dst = (satosin(sa))->sin_addr; 517 recompute: 518 #ifdef INET 519 if (sc->encap != NULL) { 520 encap_detach(sc->encap); 521 sc->encap = NULL; 522 } 523 #endif 524 if ((sc->g_src.s_addr != INADDR_ANY) && 525 (sc->g_dst.s_addr != INADDR_ANY)) { 526 bzero(&sp, sizeof(sp)); 527 bzero(&sm, sizeof(sm)); 528 bzero(&dp, sizeof(dp)); 529 bzero(&dm, sizeof(dm)); 530 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 531 sizeof(struct sockaddr_in); 532 sp.sin_family = sm.sin_family = dp.sin_family = 533 dm.sin_family = AF_INET; 534 sp.sin_addr = sc->g_src; 535 dp.sin_addr = sc->g_dst; 536 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 537 INADDR_BROADCAST; 538 #ifdef INET 539 sc->encap = encap_attach(AF_INET, sc->g_proto, 540 sintosa(&sp), sintosa(&sm), sintosa(&dp), 541 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 542 &in_gre_protosw : &in_mobile_protosw, sc); 543 if (sc->encap == NULL) 544 printf("%s: unable to attach encap\n", 545 if_name(&sc->sc_if)); 546 #endif 547 if (sc->route.ro_rt != 0) /* free old route */ 548 RTFREE(sc->route.ro_rt); 549 if (gre_compute_route(sc) == 0) 550 ifp->if_flags |= IFF_RUNNING; 551 else 552 ifp->if_flags &= ~IFF_RUNNING; 553 } 554 break; 555 case GREGADDRS: 556 memset(&si, 0, sizeof(si)); 557 si.sin_family = AF_INET; 558 si.sin_len = sizeof(struct sockaddr_in); 559 si.sin_addr.s_addr = sc->g_src.s_addr; 560 sa = sintosa(&si); 561 ifr->ifr_addr = *sa; 562 break; 563 case GREGADDRD: 564 memset(&si, 0, sizeof(si)); 565 si.sin_family = AF_INET; 566 si.sin_len = sizeof(struct sockaddr_in); 567 si.sin_addr.s_addr = sc->g_dst.s_addr; 568 sa = sintosa(&si); 569 ifr->ifr_addr = *sa; 570 break; 571 case SIOCSIFPHYADDR: 572 if ((error = suser(td)) != 0) 573 break; 574 if (aifr->ifra_addr.sin_family != AF_INET || 575 aifr->ifra_dstaddr.sin_family != AF_INET) { 576 error = EAFNOSUPPORT; 577 break; 578 } 579 if (aifr->ifra_addr.sin_len != sizeof(si) || 580 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 581 error = EINVAL; 582 break; 583 } 584 sc->g_src = aifr->ifra_addr.sin_addr; 585 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 586 goto recompute; 587 case SIOCSLIFPHYADDR: 588 if ((error = suser(td)) != 0) 589 break; 590 if (lifr->addr.ss_family != AF_INET || 591 lifr->dstaddr.ss_family != AF_INET) { 592 error = EAFNOSUPPORT; 593 break; 594 } 595 if (lifr->addr.ss_len != sizeof(si) || 596 lifr->dstaddr.ss_len != sizeof(si)) { 597 error = EINVAL; 598 break; 599 } 600 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 601 sc->g_dst = 602 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 603 goto recompute; 604 case SIOCDIFPHYADDR: 605 if ((error = suser(td)) != 0) 606 break; 607 sc->g_src.s_addr = INADDR_ANY; 608 sc->g_dst.s_addr = INADDR_ANY; 609 goto recompute; 610 case SIOCGLIFPHYADDR: 611 if (sc->g_src.s_addr == INADDR_ANY || 612 sc->g_dst.s_addr == INADDR_ANY) { 613 error = EADDRNOTAVAIL; 614 break; 615 } 616 memset(&si, 0, sizeof(si)); 617 si.sin_family = AF_INET; 618 si.sin_len = sizeof(struct sockaddr_in); 619 si.sin_addr.s_addr = sc->g_src.s_addr; 620 memcpy(&lifr->addr, &si, sizeof(si)); 621 si.sin_addr.s_addr = sc->g_dst.s_addr; 622 memcpy(&lifr->dstaddr, &si, sizeof(si)); 623 break; 624 case SIOCGIFPSRCADDR: 625 if (sc->g_src.s_addr == INADDR_ANY) { 626 error = EADDRNOTAVAIL; 627 break; 628 } 629 memset(&si, 0, sizeof(si)); 630 si.sin_family = AF_INET; 631 si.sin_len = sizeof(struct sockaddr_in); 632 si.sin_addr.s_addr = sc->g_src.s_addr; 633 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 634 break; 635 case SIOCGIFPDSTADDR: 636 if (sc->g_dst.s_addr == INADDR_ANY) { 637 error = EADDRNOTAVAIL; 638 break; 639 } 640 memset(&si, 0, sizeof(si)); 641 si.sin_family = AF_INET; 642 si.sin_len = sizeof(struct sockaddr_in); 643 si.sin_addr.s_addr = sc->g_dst.s_addr; 644 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 645 break; 646 default: 647 error = EINVAL; 648 break; 649 } 650 651 splx(s); 652 return (error); 653 } 654 655 /* 656 * computes a route to our destination that is not the one 657 * which would be taken by ip_output(), as this one will loop back to 658 * us. If the interface is p2p as a--->b, then a routing entry exists 659 * If we now send a packet to b (e.g. ping b), this will come down here 660 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 661 * if_gre. 662 * Goal here is to compute a route to b that is less specific than 663 * a-->b. We know that this one exists as in normal operation we have 664 * at least a default route which matches. 665 */ 666 static int 667 gre_compute_route(struct gre_softc *sc) 668 { 669 struct route *ro; 670 u_int32_t a, b, c; 671 672 ro = &sc->route; 673 674 memset(ro, 0, sizeof(struct route)); 675 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 676 ro->ro_dst.sa_family = AF_INET; 677 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 678 679 /* 680 * toggle last bit, so our interface is not found, but a less 681 * specific route. I'd rather like to specify a shorter mask, 682 * but this is not possible. Should work though. XXX 683 * there is a simpler way ... 684 */ 685 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 686 a = ntohl(sc->g_dst.s_addr); 687 b = a & 0x01; 688 c = a & 0xfffffffe; 689 b = b ^ 0x01; 690 a = b | c; 691 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 692 = htonl(a); 693 } 694 695 #ifdef DIAGNOSTIC 696 printf("%s: searching a route to %s", if_name(&sc->sc_if), 697 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 698 #endif 699 700 rtalloc(ro); 701 702 /* 703 * check if this returned a route at all and this route is no 704 * recursion to ourself 705 */ 706 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 707 #ifdef DIAGNOSTIC 708 if (ro->ro_rt == NULL) 709 printf(" - no route found!\n"); 710 else 711 printf(" - route loops back to ourself!\n"); 712 #endif 713 return EADDRNOTAVAIL; 714 } 715 716 /* 717 * now change it back - else ip_output will just drop 718 * the route and search one to this interface ... 719 */ 720 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 721 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 722 723 #ifdef DIAGNOSTIC 724 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 725 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 726 printf("\n"); 727 #endif 728 729 return 0; 730 } 731 732 /* 733 * do a checksum of a buffer - much like in_cksum, which operates on 734 * mbufs. 735 */ 736 u_short 737 gre_in_cksum(u_short *p, u_int len) 738 { 739 u_int sum = 0; 740 int nwords = len >> 1; 741 742 while (nwords-- != 0) 743 sum += *p++; 744 745 if (len & 1) { 746 union { 747 u_short w; 748 u_char c[2]; 749 } u; 750 u.c[0] = *(u_char *)p; 751 u.c[1] = 0; 752 sum += u.w; 753 } 754 755 /* end-around-carry */ 756 sum = (sum >> 16) + (sum & 0xffff); 757 sum += (sum >> 16); 758 return (~sum); 759 } 760 761 static int 762 gremodevent(module_t mod, int type, void *data) 763 { 764 int err; 765 766 switch (type) { 767 case MOD_LOAD: 768 greunits->rm_type = RMAN_ARRAY; 769 greunits->rm_descr = "configurable if_gre units"; 770 err = rman_init(greunits); 771 if (err != 0) 772 return (err); 773 err = rman_manage_region(greunits, 0, GRE_MAXUNIT); 774 if (err != 0) { 775 printf("%s: greunits: rman_manage_region: Failed %d\n", 776 GRENAME, err); 777 rman_fini(greunits); 778 return (err); 779 } 780 greattach(); 781 break; 782 case MOD_UNLOAD: 783 if_clone_detach(&gre_cloner); 784 785 while (!LIST_EMPTY(&gre_softc_list)) 786 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 787 788 err = rman_fini(greunits); 789 if (err != 0) 790 return (err); 791 792 break; 793 } 794 return 0; 795 } 796 797 static moduledata_t gre_mod = { 798 "if_gre", 799 gremodevent, 800 0 801 }; 802 803 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 804 MODULE_VERSION(if_gre, 1); 805