1 /* $NetBSD: if_gre.c,v 1.42 2002/08/14 00:23:27 itojun Exp $ */ 2 /* $FreeBSD$ */ 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_atalk.h" 50 #include "opt_inet.h" 51 52 #include <sys/param.h> 53 #include <sys/kernel.h> 54 #include <sys/malloc.h> 55 #include <sys/mbuf.h> 56 #include <sys/protosw.h> 57 #include <sys/socket.h> 58 #include <sys/sockio.h> 59 #include <sys/sysctl.h> 60 #include <sys/systm.h> 61 62 #include <net/ethernet.h> 63 #include <net/if.h> 64 #include <net/if_types.h> 65 #include <net/route.h> 66 67 #ifdef INET 68 #include <netinet/in.h> 69 #include <netinet/in_systm.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip.h> 72 #include <netinet/ip_gre.h> 73 #include <netinet/ip_var.h> 74 #include <netinet/ip_encap.h> 75 #else 76 #error "Huh? if_gre without inet?" 77 #endif 78 79 #include <net/bpf.h> 80 81 #include <net/net_osdep.h> 82 #include <net/if_gre.h> 83 84 /* 85 * It is not easy to calculate the right value for a GRE MTU. 86 * We leave this task to the admin and use the same default that 87 * other vendors use. 88 */ 89 #define GREMTU 1476 90 91 #define GRENAME "gre" 92 93 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 94 95 struct gre_softc_head gre_softc_list; 96 97 static int gre_clone_create(struct if_clone *, int); 98 static void gre_clone_destroy(struct ifnet *); 99 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 100 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 101 struct rtentry *rt); 102 103 static struct if_clone gre_cloner = 104 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 105 106 static int gre_compute_route(struct gre_softc *sc); 107 108 static void greattach(void); 109 110 #ifdef INET 111 extern struct domain inetdomain; 112 static const struct protosw in_gre_protosw = 113 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 114 (pr_input_t*)gre_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 115 0, 116 0, 0, 0, 0, 117 &rip_usrreqs 118 }; 119 static const struct protosw in_mobile_protosw = 120 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 121 (pr_input_t*)gre_mobile_input, (pr_output_t*)rip_output, rip_ctlinput, rip_ctloutput, 122 0, 123 0, 0, 0, 0, 124 &rip_usrreqs 125 }; 126 #endif 127 128 SYSCTL_DECL(_net_link); 129 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 130 "Generic Routing Encapsulation"); 131 #ifndef MAX_GRE_NEST 132 /* 133 * This macro controls the default upper limitation on nesting of gre tunnels. 134 * Since, setting a large value to this macro with a careless configuration 135 * may introduce system crash, we don't allow any nestings by default. 136 * If you need to configure nested gre tunnels, you can define this macro 137 * in your kernel configuration file. However, if you do so, please be 138 * careful to configure the tunnels so that it won't make a loop. 139 */ 140 #define MAX_GRE_NEST 1 141 #endif 142 static int max_gre_nesting = MAX_GRE_NEST; 143 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 144 &max_gre_nesting, 0, "Max nested tunnels"); 145 146 /* ARGSUSED */ 147 static void 148 greattach(void) 149 { 150 151 LIST_INIT(&gre_softc_list); 152 if_clone_attach(&gre_cloner); 153 } 154 155 static int 156 gre_clone_create(ifc, unit) 157 struct if_clone *ifc; 158 int unit; 159 { 160 struct gre_softc *sc; 161 162 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 163 memset(sc, 0, sizeof(struct gre_softc)); 164 165 if_initname(&sc->sc_if, ifc->ifc_name, unit); 166 sc->sc_if.if_softc = sc; 167 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 168 sc->sc_if.if_type = IFT_OTHER; 169 sc->sc_if.if_addrlen = 0; 170 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 171 sc->sc_if.if_mtu = GREMTU; 172 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 173 sc->sc_if.if_output = gre_output; 174 sc->sc_if.if_ioctl = gre_ioctl; 175 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 176 sc->g_proto = IPPROTO_GRE; 177 sc->sc_if.if_flags |= IFF_LINK0; 178 sc->encap = NULL; 179 sc->called = 0; 180 if_attach(&sc->sc_if); 181 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 182 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 183 return (0); 184 } 185 186 static void 187 gre_clone_destroy(ifp) 188 struct ifnet *ifp; 189 { 190 struct gre_softc *sc = ifp->if_softc; 191 192 #ifdef INET 193 if (sc->encap != NULL) 194 encap_detach(sc->encap); 195 #endif 196 LIST_REMOVE(sc, sc_list); 197 bpfdetach(ifp); 198 if_detach(ifp); 199 free(sc, M_GRE); 200 } 201 202 /* 203 * The output routine. Takes a packet and encapsulates it in the protocol 204 * given by sc->g_proto. See also RFC 1701 and RFC 2004 205 */ 206 static int 207 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 208 struct rtentry *rt) 209 { 210 int error = 0; 211 struct gre_softc *sc = ifp->if_softc; 212 struct greip *gh; 213 struct ip *ip; 214 u_char osrc; 215 u_short etype = 0; 216 struct mobile_h mob_h; 217 218 /* 219 * gre may cause infinite recursion calls when misconfigured. 220 * We'll prevent this by introducing upper limit. 221 */ 222 if (++(sc->called) > max_gre_nesting) { 223 printf("%s: gre_output: recursively called too many " 224 "times(%d)\n", if_name(&sc->sc_if), sc->called); 225 m_freem(m); 226 error = EIO; /* is there better errno? */ 227 goto end; 228 } 229 230 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 231 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 232 m_freem(m); 233 error = ENETDOWN; 234 goto end; 235 } 236 237 gh = NULL; 238 ip = NULL; 239 osrc = 0; 240 241 if (ifp->if_bpf) { 242 /* see comment of other if_foo.c files */ 243 struct mbuf m0; 244 u_int32_t af = dst->sa_family; 245 246 m0.m_next = m; 247 m0.m_len = 4; 248 m0.m_data = (char *)⁡ 249 250 BPF_MTAP(ifp, &m0); 251 } 252 253 m->m_flags &= ~(M_BCAST|M_MCAST); 254 255 if (sc->g_proto == IPPROTO_MOBILE) { 256 if (dst->sa_family == AF_INET) { 257 struct mbuf *m0; 258 int msiz; 259 260 ip = mtod(m, struct ip *); 261 262 /* 263 * RFC2004 specifies that fragmented diagrams shouldn't 264 * be encapsulated. 265 */ 266 if ((ip->ip_off & IP_MF) != 0) { 267 _IF_DROP(&ifp->if_snd); 268 m_freem(m); 269 error = EINVAL; /* is there better errno? */ 270 goto end; 271 } 272 memset(&mob_h, 0, MOB_H_SIZ_L); 273 mob_h.proto = (ip->ip_p) << 8; 274 mob_h.odst = ip->ip_dst.s_addr; 275 ip->ip_dst.s_addr = sc->g_dst.s_addr; 276 277 /* 278 * If the packet comes from our host, we only change 279 * the destination address in the IP header. 280 * Else we also need to save and change the source 281 */ 282 if (in_hosteq(ip->ip_src, sc->g_src)) { 283 msiz = MOB_H_SIZ_S; 284 } else { 285 mob_h.proto |= MOB_H_SBIT; 286 mob_h.osrc = ip->ip_src.s_addr; 287 ip->ip_src.s_addr = sc->g_src.s_addr; 288 msiz = MOB_H_SIZ_L; 289 } 290 mob_h.proto = htons(mob_h.proto); 291 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 292 293 if ((m->m_data - msiz) < m->m_pktdat) { 294 /* need new mbuf */ 295 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 296 if (m0 == NULL) { 297 _IF_DROP(&ifp->if_snd); 298 m_freem(m); 299 error = ENOBUFS; 300 goto end; 301 } 302 m0->m_next = m; 303 m->m_data += sizeof(struct ip); 304 m->m_len -= sizeof(struct ip); 305 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 306 m0->m_len = msiz + sizeof(struct ip); 307 m0->m_data += max_linkhdr; 308 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 309 sizeof(struct ip)); 310 m = m0; 311 } else { /* we have some space left in the old one */ 312 m->m_data -= msiz; 313 m->m_len += msiz; 314 m->m_pkthdr.len += msiz; 315 bcopy(ip, mtod(m, caddr_t), 316 sizeof(struct ip)); 317 } 318 ip = mtod(m, struct ip *); 319 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 320 ip->ip_len = ntohs(ip->ip_len) + msiz; 321 } else { /* AF_INET */ 322 _IF_DROP(&ifp->if_snd); 323 m_freem(m); 324 error = EINVAL; 325 goto end; 326 } 327 } else if (sc->g_proto == IPPROTO_GRE) { 328 switch (dst->sa_family) { 329 case AF_INET: 330 ip = mtod(m, struct ip *); 331 etype = ETHERTYPE_IP; 332 break; 333 #ifdef NETATALK 334 case AF_APPLETALK: 335 etype = ETHERTYPE_ATALK; 336 break; 337 #endif 338 default: 339 _IF_DROP(&ifp->if_snd); 340 m_freem(m); 341 error = EAFNOSUPPORT; 342 goto end; 343 } 344 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 345 } else { 346 _IF_DROP(&ifp->if_snd); 347 m_freem(m); 348 error = EINVAL; 349 goto end; 350 } 351 352 if (m == NULL) { /* impossible */ 353 _IF_DROP(&ifp->if_snd); 354 error = ENOBUFS; 355 goto end; 356 } 357 358 gh = mtod(m, struct greip *); 359 if (sc->g_proto == IPPROTO_GRE) { 360 /* we don't have any GRE flags for now */ 361 362 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 363 gh->gi_ptype = htons(etype); 364 } 365 366 gh->gi_pr = sc->g_proto; 367 if (sc->g_proto != IPPROTO_MOBILE) { 368 gh->gi_src = sc->g_src; 369 gh->gi_dst = sc->g_dst; 370 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 371 ((struct ip*)gh)->ip_ttl = GRE_TTL; 372 ((struct ip*)gh)->ip_tos = ip->ip_tos; 373 ((struct ip*)gh)->ip_id = ip->ip_id; 374 gh->gi_len = m->m_pkthdr.len; 375 } 376 377 ifp->if_opackets++; 378 ifp->if_obytes += m->m_pkthdr.len; 379 /* send it off */ 380 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 381 end: 382 sc->called = 0; 383 if (error) 384 ifp->if_oerrors++; 385 return (error); 386 } 387 388 static int 389 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 390 { 391 struct ifreq *ifr = (struct ifreq *)data; 392 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 393 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 394 struct gre_softc *sc = ifp->if_softc; 395 int s; 396 struct sockaddr_in si; 397 struct sockaddr *sa = NULL; 398 int error; 399 struct sockaddr_in sp, sm, dp, dm; 400 401 error = 0; 402 403 s = splnet(); 404 switch (cmd) { 405 case SIOCSIFADDR: 406 ifp->if_flags |= IFF_UP; 407 break; 408 case SIOCSIFDSTADDR: 409 break; 410 case SIOCSIFFLAGS: 411 if ((error = suser(curthread)) != 0) 412 break; 413 if ((ifr->ifr_flags & IFF_LINK0) != 0) 414 sc->g_proto = IPPROTO_GRE; 415 else 416 sc->g_proto = IPPROTO_MOBILE; 417 goto recompute; 418 case SIOCSIFMTU: 419 if ((error = suser(curthread)) != 0) 420 break; 421 if (ifr->ifr_mtu < 576) { 422 error = EINVAL; 423 break; 424 } 425 ifp->if_mtu = ifr->ifr_mtu; 426 break; 427 case SIOCGIFMTU: 428 ifr->ifr_mtu = sc->sc_if.if_mtu; 429 break; 430 case SIOCADDMULTI: 431 case SIOCDELMULTI: 432 if ((error = suser(curthread)) != 0) 433 break; 434 if (ifr == 0) { 435 error = EAFNOSUPPORT; 436 break; 437 } 438 switch (ifr->ifr_addr.sa_family) { 439 #ifdef INET 440 case AF_INET: 441 break; 442 #endif 443 default: 444 error = EAFNOSUPPORT; 445 break; 446 } 447 break; 448 case GRESPROTO: 449 if ((error = suser(curthread)) != 0) 450 break; 451 sc->g_proto = ifr->ifr_flags; 452 switch (sc->g_proto) { 453 case IPPROTO_GRE: 454 ifp->if_flags |= IFF_LINK0; 455 break; 456 case IPPROTO_MOBILE: 457 ifp->if_flags &= ~IFF_LINK0; 458 break; 459 default: 460 error = EPROTONOSUPPORT; 461 break; 462 } 463 goto recompute; 464 case GREGPROTO: 465 ifr->ifr_flags = sc->g_proto; 466 break; 467 case GRESADDRS: 468 case GRESADDRD: 469 if ((error = suser(curthread)) != 0) 470 break; 471 /* 472 * set tunnel endpoints, compute a less specific route 473 * to the remote end and mark if as up 474 */ 475 sa = &ifr->ifr_addr; 476 if (cmd == GRESADDRS) 477 sc->g_src = (satosin(sa))->sin_addr; 478 if (cmd == GRESADDRD) 479 sc->g_dst = (satosin(sa))->sin_addr; 480 recompute: 481 #ifdef INET 482 if (sc->encap != NULL) { 483 encap_detach(sc->encap); 484 sc->encap = NULL; 485 } 486 #endif 487 if ((sc->g_src.s_addr != INADDR_ANY) && 488 (sc->g_dst.s_addr != INADDR_ANY)) { 489 bzero(&sp, sizeof(sp)); 490 bzero(&sm, sizeof(sm)); 491 bzero(&dp, sizeof(dp)); 492 bzero(&dm, sizeof(dm)); 493 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 494 sizeof(struct sockaddr_in); 495 sp.sin_family = sm.sin_family = dp.sin_family = 496 dm.sin_family = AF_INET; 497 sp.sin_addr = sc->g_src; 498 dp.sin_addr = sc->g_dst; 499 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 500 INADDR_BROADCAST; 501 #ifdef INET 502 sc->encap = encap_attach(AF_INET, sc->g_proto, 503 sintosa(&sp), sintosa(&sm), sintosa(&dp), 504 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 505 &in_gre_protosw : &in_mobile_protosw, sc); 506 if (sc->encap == NULL) 507 printf("%s: unable to attach encap\n", 508 if_name(&sc->sc_if)); 509 #endif 510 if (sc->route.ro_rt != 0) /* free old route */ 511 RTFREE(sc->route.ro_rt); 512 if (gre_compute_route(sc) == 0) 513 ifp->if_flags |= IFF_RUNNING; 514 else 515 ifp->if_flags &= ~IFF_RUNNING; 516 } 517 break; 518 case GREGADDRS: 519 memset(&si, 0, sizeof(si)); 520 si.sin_family = AF_INET; 521 si.sin_len = sizeof(struct sockaddr_in); 522 si.sin_addr.s_addr = sc->g_src.s_addr; 523 sa = sintosa(&si); 524 ifr->ifr_addr = *sa; 525 break; 526 case GREGADDRD: 527 memset(&si, 0, sizeof(si)); 528 si.sin_family = AF_INET; 529 si.sin_len = sizeof(struct sockaddr_in); 530 si.sin_addr.s_addr = sc->g_dst.s_addr; 531 sa = sintosa(&si); 532 ifr->ifr_addr = *sa; 533 break; 534 case SIOCSIFPHYADDR: 535 if ((error = suser(curthread)) != 0) 536 break; 537 if (aifr->ifra_addr.sin_family != AF_INET || 538 aifr->ifra_dstaddr.sin_family != AF_INET) { 539 error = EAFNOSUPPORT; 540 break; 541 } 542 if (aifr->ifra_addr.sin_len != sizeof(si) || 543 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 544 error = EINVAL; 545 break; 546 } 547 sc->g_src = aifr->ifra_addr.sin_addr; 548 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 549 goto recompute; 550 case SIOCSLIFPHYADDR: 551 if ((error = suser(curthread)) != 0) 552 break; 553 if (lifr->addr.ss_family != AF_INET || 554 lifr->dstaddr.ss_family != AF_INET) { 555 error = EAFNOSUPPORT; 556 break; 557 } 558 if (lifr->addr.ss_len != sizeof(si) || 559 lifr->dstaddr.ss_len != sizeof(si)) { 560 error = EINVAL; 561 break; 562 } 563 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 564 sc->g_dst = 565 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 566 goto recompute; 567 case SIOCDIFPHYADDR: 568 if ((error = suser(curthread)) != 0) 569 break; 570 sc->g_src.s_addr = INADDR_ANY; 571 sc->g_dst.s_addr = INADDR_ANY; 572 goto recompute; 573 case SIOCGLIFPHYADDR: 574 if (sc->g_src.s_addr == INADDR_ANY || 575 sc->g_dst.s_addr == INADDR_ANY) { 576 error = EADDRNOTAVAIL; 577 break; 578 } 579 memset(&si, 0, sizeof(si)); 580 si.sin_family = AF_INET; 581 si.sin_len = sizeof(struct sockaddr_in); 582 si.sin_addr.s_addr = sc->g_src.s_addr; 583 memcpy(&lifr->addr, &si, sizeof(si)); 584 si.sin_addr.s_addr = sc->g_dst.s_addr; 585 memcpy(&lifr->dstaddr, &si, sizeof(si)); 586 break; 587 case SIOCGIFPSRCADDR: 588 if (sc->g_src.s_addr == INADDR_ANY) { 589 error = EADDRNOTAVAIL; 590 break; 591 } 592 memset(&si, 0, sizeof(si)); 593 si.sin_family = AF_INET; 594 si.sin_len = sizeof(struct sockaddr_in); 595 si.sin_addr.s_addr = sc->g_src.s_addr; 596 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 597 break; 598 case SIOCGIFPDSTADDR: 599 if (sc->g_dst.s_addr == INADDR_ANY) { 600 error = EADDRNOTAVAIL; 601 break; 602 } 603 memset(&si, 0, sizeof(si)); 604 si.sin_family = AF_INET; 605 si.sin_len = sizeof(struct sockaddr_in); 606 si.sin_addr.s_addr = sc->g_dst.s_addr; 607 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 608 break; 609 default: 610 error = EINVAL; 611 break; 612 } 613 614 splx(s); 615 return (error); 616 } 617 618 /* 619 * computes a route to our destination that is not the one 620 * which would be taken by ip_output(), as this one will loop back to 621 * us. If the interface is p2p as a--->b, then a routing entry exists 622 * If we now send a packet to b (e.g. ping b), this will come down here 623 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 624 * if_gre. 625 * Goal here is to compute a route to b that is less specific than 626 * a-->b. We know that this one exists as in normal operation we have 627 * at least a default route which matches. 628 */ 629 static int 630 gre_compute_route(struct gre_softc *sc) 631 { 632 struct route *ro; 633 u_int32_t a, b, c; 634 635 ro = &sc->route; 636 637 memset(ro, 0, sizeof(struct route)); 638 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 639 ro->ro_dst.sa_family = AF_INET; 640 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 641 642 /* 643 * toggle last bit, so our interface is not found, but a less 644 * specific route. I'd rather like to specify a shorter mask, 645 * but this is not possible. Should work though. XXX 646 * there is a simpler way ... 647 */ 648 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 649 a = ntohl(sc->g_dst.s_addr); 650 b = a & 0x01; 651 c = a & 0xfffffffe; 652 b = b ^ 0x01; 653 a = b | c; 654 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 655 = htonl(a); 656 } 657 658 #ifdef DIAGNOSTIC 659 printf("%s: searching a route to %s", if_name(&sc->sc_if), 660 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 661 #endif 662 663 rtalloc(ro); 664 665 /* 666 * check if this returned a route at all and this route is no 667 * recursion to ourself 668 */ 669 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 670 #ifdef DIAGNOSTIC 671 if (ro->ro_rt == NULL) 672 printf(" - no route found!\n"); 673 else 674 printf(" - route loops back to ourself!\n"); 675 #endif 676 return EADDRNOTAVAIL; 677 } 678 679 /* 680 * now change it back - else ip_output will just drop 681 * the route and search one to this interface ... 682 */ 683 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 684 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 685 686 #ifdef DIAGNOSTIC 687 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 688 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 689 printf("\n"); 690 #endif 691 692 return 0; 693 } 694 695 /* 696 * do a checksum of a buffer - much like in_cksum, which operates on 697 * mbufs. 698 */ 699 u_short 700 gre_in_cksum(u_short *p, u_int len) 701 { 702 u_int sum = 0; 703 int nwords = len >> 1; 704 705 while (nwords-- != 0) 706 sum += *p++; 707 708 if (len & 1) { 709 union { 710 u_short w; 711 u_char c[2]; 712 } u; 713 u.c[0] = *(u_char *)p; 714 u.c[1] = 0; 715 sum += u.w; 716 } 717 718 /* end-around-carry */ 719 sum = (sum >> 16) + (sum & 0xffff); 720 sum += (sum >> 16); 721 return (~sum); 722 } 723 724 static int 725 gremodevent(module_t mod, int type, void *data) 726 { 727 728 switch (type) { 729 case MOD_LOAD: 730 greattach(); 731 break; 732 case MOD_UNLOAD: 733 if_clone_detach(&gre_cloner); 734 735 while (!LIST_EMPTY(&gre_softc_list)) 736 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 737 break; 738 } 739 return 0; 740 } 741 742 static moduledata_t gre_mod = { 743 "if_gre", 744 gremodevent, 745 0 746 }; 747 748 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 749 MODULE_VERSION(if_gre, 1); 750