1 /* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 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 #include "opt_inet6.h" 52 53 #include <sys/param.h> 54 #include <sys/kernel.h> 55 #include <sys/malloc.h> 56 #include <sys/module.h> 57 #include <sys/mbuf.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 64 #include <net/ethernet.h> 65 #include <net/if.h> 66 #include <net/if_clone.h> 67 #include <net/if_types.h> 68 #include <net/route.h> 69 70 #ifdef INET 71 #include <netinet/in.h> 72 #include <netinet/in_systm.h> 73 #include <netinet/in_var.h> 74 #include <netinet/ip.h> 75 #include <netinet/ip_gre.h> 76 #include <netinet/ip_var.h> 77 #include <netinet/ip_encap.h> 78 #else 79 #error "Huh? if_gre without inet?" 80 #endif 81 82 #include <net/bpf.h> 83 84 #include <net/net_osdep.h> 85 #include <net/if_gre.h> 86 87 /* 88 * It is not easy to calculate the right value for a GRE MTU. 89 * We leave this task to the admin and use the same default that 90 * other vendors use. 91 */ 92 #define GREMTU 1476 93 94 #define GRENAME "gre" 95 96 /* 97 * gre_mtx protects all global variables in if_gre.c. 98 * XXX: gre_softc data not protected yet. 99 */ 100 struct mtx gre_mtx; 101 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 102 103 struct gre_softc_head gre_softc_list; 104 105 static int gre_clone_create(struct if_clone *, int); 106 static void gre_clone_destroy(struct ifnet *); 107 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 108 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 109 struct rtentry *rt); 110 111 IFC_SIMPLE_DECLARE(gre, 0); 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 (pr_input_t*)gre_input, (pr_output_t*)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 (pr_input_t*)gre_mobile_input, (pr_output_t*)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_TUNNEL, 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 mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF); 159 LIST_INIT(&gre_softc_list); 160 if_clone_attach(&gre_cloner); 161 } 162 163 static int 164 gre_clone_create(ifc, unit) 165 struct if_clone *ifc; 166 int unit; 167 { 168 struct gre_softc *sc; 169 170 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO); 171 172 if_initname(&sc->sc_if, ifc->ifc_name, unit); 173 sc->sc_if.if_softc = sc; 174 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 175 sc->sc_if.if_type = IFT_TUNNEL; 176 sc->sc_if.if_addrlen = 0; 177 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 178 sc->sc_if.if_mtu = GREMTU; 179 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 180 sc->sc_if.if_output = gre_output; 181 sc->sc_if.if_ioctl = gre_ioctl; 182 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 183 sc->g_proto = IPPROTO_GRE; 184 sc->sc_if.if_flags |= IFF_LINK0; 185 sc->encap = NULL; 186 sc->called = 0; 187 sc->wccp_ver = WCCP_V1; 188 if_attach(&sc->sc_if); 189 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 190 mtx_lock(&gre_mtx); 191 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 192 mtx_unlock(&gre_mtx); 193 return (0); 194 } 195 196 static void 197 gre_destroy(struct gre_softc *sc) 198 { 199 200 #ifdef INET 201 if (sc->encap != NULL) 202 encap_detach(sc->encap); 203 #endif 204 bpfdetach(&sc->sc_if); 205 if_detach(&sc->sc_if); 206 free(sc, M_GRE); 207 } 208 209 static void 210 gre_clone_destroy(ifp) 211 struct ifnet *ifp; 212 { 213 struct gre_softc *sc = ifp->if_softc; 214 215 mtx_lock(&gre_mtx); 216 LIST_REMOVE(sc, sc_list); 217 mtx_unlock(&gre_mtx); 218 gre_destroy(sc); 219 } 220 221 /* 222 * The output routine. Takes a packet and encapsulates it in the protocol 223 * given by sc->g_proto. See also RFC 1701 and RFC 2004 224 */ 225 static int 226 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 227 struct rtentry *rt) 228 { 229 int error = 0; 230 struct gre_softc *sc = ifp->if_softc; 231 struct greip *gh; 232 struct ip *ip; 233 u_int16_t etype = 0; 234 struct mobile_h mob_h; 235 236 /* 237 * gre may cause infinite recursion calls when misconfigured. 238 * We'll prevent this by introducing upper limit. 239 */ 240 if (++(sc->called) > max_gre_nesting) { 241 printf("%s: gre_output: recursively called too many " 242 "times(%d)\n", if_name(&sc->sc_if), sc->called); 243 m_freem(m); 244 error = EIO; /* is there better errno? */ 245 goto end; 246 } 247 248 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 249 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 250 m_freem(m); 251 error = ENETDOWN; 252 goto end; 253 } 254 255 gh = NULL; 256 ip = NULL; 257 258 if (ifp->if_bpf) { 259 u_int32_t af = dst->sa_family; 260 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m); 261 } 262 263 m->m_flags &= ~(M_BCAST|M_MCAST); 264 265 if (sc->g_proto == IPPROTO_MOBILE) { 266 if (dst->sa_family == AF_INET) { 267 struct mbuf *m0; 268 int msiz; 269 270 ip = mtod(m, struct ip *); 271 272 /* 273 * RFC2004 specifies that fragmented diagrams shouldn't 274 * be encapsulated. 275 */ 276 if ((ip->ip_off & IP_MF) != 0) { 277 _IF_DROP(&ifp->if_snd); 278 m_freem(m); 279 error = EINVAL; /* is there better errno? */ 280 goto end; 281 } 282 memset(&mob_h, 0, MOB_H_SIZ_L); 283 mob_h.proto = (ip->ip_p) << 8; 284 mob_h.odst = ip->ip_dst.s_addr; 285 ip->ip_dst.s_addr = sc->g_dst.s_addr; 286 287 /* 288 * If the packet comes from our host, we only change 289 * the destination address in the IP header. 290 * Else we also need to save and change the source 291 */ 292 if (in_hosteq(ip->ip_src, sc->g_src)) { 293 msiz = MOB_H_SIZ_S; 294 } else { 295 mob_h.proto |= MOB_H_SBIT; 296 mob_h.osrc = ip->ip_src.s_addr; 297 ip->ip_src.s_addr = sc->g_src.s_addr; 298 msiz = MOB_H_SIZ_L; 299 } 300 mob_h.proto = htons(mob_h.proto); 301 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 302 303 if ((m->m_data - msiz) < m->m_pktdat) { 304 /* need new mbuf */ 305 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 306 if (m0 == NULL) { 307 _IF_DROP(&ifp->if_snd); 308 m_freem(m); 309 error = ENOBUFS; 310 goto end; 311 } 312 m0->m_next = m; 313 m->m_data += sizeof(struct ip); 314 m->m_len -= sizeof(struct ip); 315 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 316 m0->m_len = msiz + sizeof(struct ip); 317 m0->m_data += max_linkhdr; 318 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 319 sizeof(struct ip)); 320 m = m0; 321 } else { /* we have some space left in the old one */ 322 m->m_data -= msiz; 323 m->m_len += msiz; 324 m->m_pkthdr.len += msiz; 325 bcopy(ip, mtod(m, caddr_t), 326 sizeof(struct ip)); 327 } 328 ip = mtod(m, struct ip *); 329 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 330 ip->ip_len = ntohs(ip->ip_len) + msiz; 331 } else { /* AF_INET */ 332 _IF_DROP(&ifp->if_snd); 333 m_freem(m); 334 error = EINVAL; 335 goto end; 336 } 337 } else if (sc->g_proto == IPPROTO_GRE) { 338 switch (dst->sa_family) { 339 case AF_INET: 340 ip = mtod(m, struct ip *); 341 etype = ETHERTYPE_IP; 342 break; 343 #ifdef NETATALK 344 case AF_APPLETALK: 345 etype = ETHERTYPE_ATALK; 346 break; 347 #endif 348 default: 349 _IF_DROP(&ifp->if_snd); 350 m_freem(m); 351 error = EAFNOSUPPORT; 352 goto end; 353 } 354 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 355 } else { 356 _IF_DROP(&ifp->if_snd); 357 m_freem(m); 358 error = EINVAL; 359 goto end; 360 } 361 362 if (m == NULL) { /* mbuf allocation failed */ 363 _IF_DROP(&ifp->if_snd); 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 memset((void *)gh, 0, sizeof(struct greip)); 372 gh->gi_ptype = htons(etype); 373 } 374 375 gh->gi_pr = sc->g_proto; 376 if (sc->g_proto != IPPROTO_MOBILE) { 377 gh->gi_src = sc->g_src; 378 gh->gi_dst = sc->g_dst; 379 ((struct ip*)gh)->ip_v = IPPROTO_IPV4; 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 ifp->if_opackets++; 388 ifp->if_obytes += m->m_pkthdr.len; 389 /* 390 * Send it off and with IP_FORWARD flag to prevent it from 391 * overwriting the ip_id again. ip_id is already set to the 392 * ip_id of the encapsulated packet. 393 */ 394 error = ip_output(m, NULL, &sc->route, IP_FORWARDING, 395 (struct ip_moptions *)NULL, (struct inpcb *)NULL); 396 end: 397 sc->called = 0; 398 if (error) 399 ifp->if_oerrors++; 400 return (error); 401 } 402 403 static int 404 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 405 { 406 struct ifreq *ifr = (struct ifreq *)data; 407 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 408 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 409 struct gre_softc *sc = ifp->if_softc; 410 int s; 411 struct sockaddr_in si; 412 struct sockaddr *sa = NULL; 413 int error; 414 struct sockaddr_in sp, sm, dp, dm; 415 416 error = 0; 417 418 s = splnet(); 419 switch (cmd) { 420 case SIOCSIFADDR: 421 ifp->if_flags |= IFF_UP; 422 break; 423 case SIOCSIFDSTADDR: 424 break; 425 case SIOCSIFFLAGS: 426 if ((error = suser(curthread)) != 0) 427 break; 428 if ((ifr->ifr_flags & IFF_LINK0) != 0) 429 sc->g_proto = IPPROTO_GRE; 430 else 431 sc->g_proto = IPPROTO_MOBILE; 432 if ((ifr->ifr_flags & IFF_LINK2) != 0) 433 sc->wccp_ver = WCCP_V2; 434 else 435 sc->wccp_ver = WCCP_V1; 436 goto recompute; 437 case SIOCSIFMTU: 438 if ((error = suser(curthread)) != 0) 439 break; 440 if (ifr->ifr_mtu < 576) { 441 error = EINVAL; 442 break; 443 } 444 ifp->if_mtu = ifr->ifr_mtu; 445 break; 446 case SIOCGIFMTU: 447 ifr->ifr_mtu = sc->sc_if.if_mtu; 448 break; 449 case SIOCADDMULTI: 450 case SIOCDELMULTI: 451 if ((error = suser(curthread)) != 0) 452 break; 453 if (ifr == 0) { 454 error = EAFNOSUPPORT; 455 break; 456 } 457 switch (ifr->ifr_addr.sa_family) { 458 #ifdef INET 459 case AF_INET: 460 break; 461 #endif 462 default: 463 error = EAFNOSUPPORT; 464 break; 465 } 466 break; 467 case GRESPROTO: 468 if ((error = suser(curthread)) != 0) 469 break; 470 sc->g_proto = ifr->ifr_flags; 471 switch (sc->g_proto) { 472 case IPPROTO_GRE: 473 ifp->if_flags |= IFF_LINK0; 474 break; 475 case IPPROTO_MOBILE: 476 ifp->if_flags &= ~IFF_LINK0; 477 break; 478 default: 479 error = EPROTONOSUPPORT; 480 break; 481 } 482 goto recompute; 483 case GREGPROTO: 484 ifr->ifr_flags = sc->g_proto; 485 break; 486 case GRESADDRS: 487 case GRESADDRD: 488 if ((error = suser(curthread)) != 0) 489 break; 490 /* 491 * set tunnel endpoints, compute a less specific route 492 * to the remote end and mark if as up 493 */ 494 sa = &ifr->ifr_addr; 495 if (cmd == GRESADDRS) 496 sc->g_src = (satosin(sa))->sin_addr; 497 if (cmd == GRESADDRD) 498 sc->g_dst = (satosin(sa))->sin_addr; 499 recompute: 500 #ifdef INET 501 if (sc->encap != NULL) { 502 encap_detach(sc->encap); 503 sc->encap = NULL; 504 } 505 #endif 506 if ((sc->g_src.s_addr != INADDR_ANY) && 507 (sc->g_dst.s_addr != INADDR_ANY)) { 508 bzero(&sp, sizeof(sp)); 509 bzero(&sm, sizeof(sm)); 510 bzero(&dp, sizeof(dp)); 511 bzero(&dm, sizeof(dm)); 512 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 513 sizeof(struct sockaddr_in); 514 sp.sin_family = sm.sin_family = dp.sin_family = 515 dm.sin_family = AF_INET; 516 sp.sin_addr = sc->g_src; 517 dp.sin_addr = sc->g_dst; 518 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 519 INADDR_BROADCAST; 520 #ifdef INET 521 sc->encap = encap_attach(AF_INET, sc->g_proto, 522 sintosa(&sp), sintosa(&sm), sintosa(&dp), 523 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 524 &in_gre_protosw : &in_mobile_protosw, sc); 525 if (sc->encap == NULL) 526 printf("%s: unable to attach encap\n", 527 if_name(&sc->sc_if)); 528 #endif 529 if (sc->route.ro_rt != 0) /* free old route */ 530 RTFREE(sc->route.ro_rt); 531 if (gre_compute_route(sc) == 0) 532 ifp->if_flags |= IFF_RUNNING; 533 else 534 ifp->if_flags &= ~IFF_RUNNING; 535 } 536 break; 537 case GREGADDRS: 538 memset(&si, 0, sizeof(si)); 539 si.sin_family = AF_INET; 540 si.sin_len = sizeof(struct sockaddr_in); 541 si.sin_addr.s_addr = sc->g_src.s_addr; 542 sa = sintosa(&si); 543 ifr->ifr_addr = *sa; 544 break; 545 case GREGADDRD: 546 memset(&si, 0, sizeof(si)); 547 si.sin_family = AF_INET; 548 si.sin_len = sizeof(struct sockaddr_in); 549 si.sin_addr.s_addr = sc->g_dst.s_addr; 550 sa = sintosa(&si); 551 ifr->ifr_addr = *sa; 552 break; 553 case SIOCSIFPHYADDR: 554 if ((error = suser(curthread)) != 0) 555 break; 556 if (aifr->ifra_addr.sin_family != AF_INET || 557 aifr->ifra_dstaddr.sin_family != AF_INET) { 558 error = EAFNOSUPPORT; 559 break; 560 } 561 if (aifr->ifra_addr.sin_len != sizeof(si) || 562 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 563 error = EINVAL; 564 break; 565 } 566 sc->g_src = aifr->ifra_addr.sin_addr; 567 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 568 goto recompute; 569 case SIOCSLIFPHYADDR: 570 if ((error = suser(curthread)) != 0) 571 break; 572 if (lifr->addr.ss_family != AF_INET || 573 lifr->dstaddr.ss_family != AF_INET) { 574 error = EAFNOSUPPORT; 575 break; 576 } 577 if (lifr->addr.ss_len != sizeof(si) || 578 lifr->dstaddr.ss_len != sizeof(si)) { 579 error = EINVAL; 580 break; 581 } 582 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 583 sc->g_dst = 584 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 585 goto recompute; 586 case SIOCDIFPHYADDR: 587 if ((error = suser(curthread)) != 0) 588 break; 589 sc->g_src.s_addr = INADDR_ANY; 590 sc->g_dst.s_addr = INADDR_ANY; 591 goto recompute; 592 case SIOCGLIFPHYADDR: 593 if (sc->g_src.s_addr == INADDR_ANY || 594 sc->g_dst.s_addr == INADDR_ANY) { 595 error = EADDRNOTAVAIL; 596 break; 597 } 598 memset(&si, 0, sizeof(si)); 599 si.sin_family = AF_INET; 600 si.sin_len = sizeof(struct sockaddr_in); 601 si.sin_addr.s_addr = sc->g_src.s_addr; 602 memcpy(&lifr->addr, &si, sizeof(si)); 603 si.sin_addr.s_addr = sc->g_dst.s_addr; 604 memcpy(&lifr->dstaddr, &si, sizeof(si)); 605 break; 606 case SIOCGIFPSRCADDR: 607 #ifdef INET6 608 case SIOCGIFPSRCADDR_IN6: 609 #endif 610 if (sc->g_src.s_addr == INADDR_ANY) { 611 error = EADDRNOTAVAIL; 612 break; 613 } 614 memset(&si, 0, sizeof(si)); 615 si.sin_family = AF_INET; 616 si.sin_len = sizeof(struct sockaddr_in); 617 si.sin_addr.s_addr = sc->g_src.s_addr; 618 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 619 break; 620 case SIOCGIFPDSTADDR: 621 #ifdef INET6 622 case SIOCGIFPDSTADDR_IN6: 623 #endif 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 splx(s); 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_output() 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 printf("%s: searching for 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 printf(" - no route found!\n"); 698 else 699 printf(" - 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 printf(", 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 printf("\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_int16_t 725 gre_in_cksum(u_int16_t *p, u_int len) 726 { 727 u_int32_t 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 struct gre_softc *sc; 753 754 switch (type) { 755 case MOD_LOAD: 756 greattach(); 757 break; 758 case MOD_UNLOAD: 759 if_clone_detach(&gre_cloner); 760 761 mtx_lock(&gre_mtx); 762 while ((sc = LIST_FIRST(&gre_softc_list)) != NULL) { 763 LIST_REMOVE(sc, sc_list); 764 mtx_unlock(&gre_mtx); 765 gre_destroy(sc); 766 mtx_lock(&gre_mtx); 767 } 768 mtx_unlock(&gre_mtx); 769 mtx_destroy(&gre_mtx); 770 break; 771 default: 772 return EOPNOTSUPP; 773 } 774 return 0; 775 } 776 777 static moduledata_t gre_mod = { 778 "if_gre", 779 gremodevent, 780 0 781 }; 782 783 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 784 MODULE_VERSION(if_gre, 1); 785