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_atalk.h" 50 #include "opt_inet.h" 51 52 #include <sys/param.h> 53 #include <sys/kernel.h> 54 #include <sys/bus.h> 55 #include <sys/malloc.h> 56 #include <sys/mbuf.h> 57 #include <sys/proc.h> 58 #include <sys/priv.h> 59 #include <sys/protosw.h> 60 #include <sys/socket.h> 61 #include <sys/sockio.h> 62 #include <sys/sysctl.h> 63 #include <sys/systm.h> 64 #include <sys/thread2.h> 65 66 #include <net/ethernet.h> 67 #include <net/if.h> 68 #include <net/if_types.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 sc->sc_if.if_snd.ifq_maxlen = 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_char osrc; 240 u_short etype = 0; 241 struct mobile_h mob_h; 242 243 /* 244 * gre may cause infinite recursion calls when misconfigured. 245 * We'll prevent this by introducing upper limit. 246 */ 247 if (++(sc->called) > max_gre_nesting) { 248 kprintf("%s: gre_output: recursively called too many " 249 "times(%d)\n", if_name(&sc->sc_if), sc->called); 250 m_freem(m); 251 error = EIO; /* is there better errno? */ 252 goto end; 253 } 254 255 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 256 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 257 m_freem(m); 258 error = ENETDOWN; 259 goto end; 260 } 261 262 gh = NULL; 263 ip = NULL; 264 osrc = 0; 265 266 if (ifp->if_bpf) { 267 uint32_t af = dst->sa_family; 268 269 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 270 } 271 272 m->m_flags &= ~(M_BCAST|M_MCAST); 273 274 if (sc->g_proto == IPPROTO_MOBILE) { 275 if (dst->sa_family == AF_INET) { 276 struct mbuf *m0; 277 int msiz; 278 279 ip = mtod(m, struct ip *); 280 281 /* 282 * RFC2004 specifies that fragmented datagrams shouldn't 283 * be encapsulated. 284 */ 285 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 286 IF_DROP(&ifp->if_snd); 287 m_freem(m); 288 error = EINVAL; /* is there better errno? */ 289 goto end; 290 } 291 memset(&mob_h, 0, MOB_H_SIZ_L); 292 mob_h.proto = (ip->ip_p) << 8; 293 mob_h.odst = ip->ip_dst.s_addr; 294 ip->ip_dst.s_addr = sc->g_dst.s_addr; 295 296 /* 297 * If the packet comes from our host, we only change 298 * the destination address in the IP header. 299 * Else we also need to save and change the source 300 */ 301 if (in_hosteq(ip->ip_src, sc->g_src)) { 302 msiz = MOB_H_SIZ_S; 303 } else { 304 mob_h.proto |= MOB_H_SBIT; 305 mob_h.osrc = ip->ip_src.s_addr; 306 ip->ip_src.s_addr = sc->g_src.s_addr; 307 msiz = MOB_H_SIZ_L; 308 } 309 mob_h.proto = htons(mob_h.proto); 310 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 311 312 if ((m->m_data - msiz) < m->m_pktdat) { 313 /* need new mbuf */ 314 MGETHDR(m0, MB_DONTWAIT, MT_HEADER); 315 if (m0 == NULL) { 316 IF_DROP(&ifp->if_snd); 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 IF_DROP(&ifp->if_snd); 342 m_freem(m); 343 error = EINVAL; 344 goto end; 345 } 346 } else if (sc->g_proto == IPPROTO_GRE) { 347 switch (dst->sa_family) { 348 case AF_INET: 349 ip = mtod(m, struct ip *); 350 etype = ETHERTYPE_IP; 351 break; 352 #ifdef NETATALK 353 case AF_APPLETALK: 354 etype = ETHERTYPE_ATALK; 355 break; 356 #endif 357 default: 358 IF_DROP(&ifp->if_snd); 359 m_freem(m); 360 error = EAFNOSUPPORT; 361 goto end; 362 } 363 M_PREPEND(m, sizeof(struct greip), MB_DONTWAIT); 364 } else { 365 IF_DROP(&ifp->if_snd); 366 m_freem(m); 367 error = EINVAL; 368 goto end; 369 } 370 371 if (m == NULL) { /* impossible */ 372 IF_DROP(&ifp->if_snd); 373 error = ENOBUFS; 374 goto end; 375 } 376 377 gh = mtod(m, struct greip *); 378 if (sc->g_proto == IPPROTO_GRE) { 379 /* we don't have any GRE flags for now */ 380 381 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 382 gh->gi_ptype = htons(etype); 383 } 384 385 gh->gi_pr = sc->g_proto; 386 if (sc->g_proto != IPPROTO_MOBILE) { 387 gh->gi_src = sc->g_src; 388 gh->gi_dst = sc->g_dst; 389 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 390 ((struct ip*)gh)->ip_ttl = GRE_TTL; 391 ((struct ip*)gh)->ip_tos = ip->ip_tos; 392 ((struct ip*)gh)->ip_id = ip->ip_id; 393 gh->gi_len = m->m_pkthdr.len; 394 } 395 396 ifp->if_opackets++; 397 ifp->if_obytes += m->m_pkthdr.len; 398 /* send it off */ 399 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 400 end: 401 sc->called = 0; 402 if (error) 403 ifp->if_oerrors++; 404 return (error); 405 } 406 407 static int 408 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 409 struct rtentry *rt) 410 { 411 int error; 412 413 ifnet_serialize_tx(ifp); 414 error = gre_output_serialized(ifp, m, dst, rt); 415 ifnet_deserialize_tx(ifp); 416 417 return error; 418 } 419 420 static int 421 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 422 { 423 struct ifreq *ifr = (struct ifreq *)data; 424 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 425 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 426 struct gre_softc *sc = ifp->if_softc; 427 struct sockaddr_in si; 428 struct sockaddr *sa = NULL; 429 int error; 430 struct sockaddr_in sp, sm, dp, dm; 431 432 error = 0; 433 434 crit_enter(); 435 switch (cmd) { 436 case SIOCSIFADDR: 437 ifp->if_flags |= IFF_UP; 438 break; 439 case SIOCSIFDSTADDR: 440 break; 441 case SIOCSIFFLAGS: 442 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 443 break; 444 if ((ifr->ifr_flags & IFF_LINK0) != 0) 445 sc->g_proto = IPPROTO_GRE; 446 else 447 sc->g_proto = IPPROTO_MOBILE; 448 goto recompute; 449 case SIOCSIFMTU: 450 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 451 break; 452 if (ifr->ifr_mtu < 576) { 453 error = EINVAL; 454 break; 455 } 456 ifp->if_mtu = ifr->ifr_mtu; 457 break; 458 case SIOCGIFMTU: 459 ifr->ifr_mtu = sc->sc_if.if_mtu; 460 break; 461 case SIOCADDMULTI: 462 case SIOCDELMULTI: 463 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 464 break; 465 if (ifr == 0) { 466 error = EAFNOSUPPORT; 467 break; 468 } 469 switch (ifr->ifr_addr.sa_family) { 470 #ifdef INET 471 case AF_INET: 472 break; 473 #endif 474 default: 475 error = EAFNOSUPPORT; 476 break; 477 } 478 break; 479 case GRESPROTO: 480 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 481 break; 482 sc->g_proto = ifr->ifr_flags; 483 switch (sc->g_proto) { 484 case IPPROTO_GRE: 485 ifp->if_flags |= IFF_LINK0; 486 break; 487 case IPPROTO_MOBILE: 488 ifp->if_flags &= ~IFF_LINK0; 489 break; 490 default: 491 error = EPROTONOSUPPORT; 492 break; 493 } 494 goto recompute; 495 case GREGPROTO: 496 ifr->ifr_flags = sc->g_proto; 497 break; 498 case GRESADDRS: 499 case GRESADDRD: 500 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 501 break; 502 /* 503 * set tunnel endpoints, compute a less specific route 504 * to the remote end and mark if as up 505 */ 506 sa = &ifr->ifr_addr; 507 if (cmd == GRESADDRS) 508 sc->g_src = (satosin(sa))->sin_addr; 509 if (cmd == GRESADDRD) 510 sc->g_dst = (satosin(sa))->sin_addr; 511 recompute: 512 #ifdef INET 513 if (sc->encap != NULL) { 514 encap_detach(sc->encap); 515 sc->encap = NULL; 516 } 517 #endif 518 if ((sc->g_src.s_addr != INADDR_ANY) && 519 (sc->g_dst.s_addr != INADDR_ANY)) { 520 bzero(&sp, sizeof(sp)); 521 bzero(&sm, sizeof(sm)); 522 bzero(&dp, sizeof(dp)); 523 bzero(&dm, sizeof(dm)); 524 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 525 sizeof(struct sockaddr_in); 526 sp.sin_family = sm.sin_family = dp.sin_family = 527 dm.sin_family = AF_INET; 528 sp.sin_addr = sc->g_src; 529 dp.sin_addr = sc->g_dst; 530 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 531 INADDR_BROADCAST; 532 #ifdef INET 533 sc->encap = encap_attach(AF_INET, sc->g_proto, 534 sintosa(&sp), sintosa(&sm), sintosa(&dp), 535 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 536 &in_gre_protosw : &in_mobile_protosw, sc); 537 if (sc->encap == NULL) 538 kprintf("%s: unable to attach encap\n", 539 if_name(&sc->sc_if)); 540 #endif 541 if (sc->route.ro_rt != 0) /* free old route */ 542 RTFREE(sc->route.ro_rt); 543 if (gre_compute_route(sc) == 0) 544 ifp->if_flags |= IFF_RUNNING; 545 else 546 ifp->if_flags &= ~IFF_RUNNING; 547 } 548 break; 549 case GREGADDRS: 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_src.s_addr; 554 sa = sintosa(&si); 555 ifr->ifr_addr = *sa; 556 break; 557 case GREGADDRD: 558 memset(&si, 0, sizeof(si)); 559 si.sin_family = AF_INET; 560 si.sin_len = sizeof(struct sockaddr_in); 561 si.sin_addr.s_addr = sc->g_dst.s_addr; 562 sa = sintosa(&si); 563 ifr->ifr_addr = *sa; 564 break; 565 case SIOCSIFPHYADDR: 566 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 567 break; 568 if (aifr->ifra_addr.sin_family != AF_INET || 569 aifr->ifra_dstaddr.sin_family != AF_INET) { 570 error = EAFNOSUPPORT; 571 break; 572 } 573 if (aifr->ifra_addr.sin_len != sizeof(si) || 574 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 575 error = EINVAL; 576 break; 577 } 578 sc->g_src = aifr->ifra_addr.sin_addr; 579 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 580 goto recompute; 581 case SIOCSLIFPHYADDR: 582 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 583 break; 584 if (lifr->addr.ss_family != AF_INET || 585 lifr->dstaddr.ss_family != AF_INET) { 586 error = EAFNOSUPPORT; 587 break; 588 } 589 if (lifr->addr.ss_len != sizeof(si) || 590 lifr->dstaddr.ss_len != sizeof(si)) { 591 error = EINVAL; 592 break; 593 } 594 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 595 sc->g_dst = 596 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 597 goto recompute; 598 case SIOCDIFPHYADDR: 599 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 600 break; 601 sc->g_src.s_addr = INADDR_ANY; 602 sc->g_dst.s_addr = INADDR_ANY; 603 goto recompute; 604 case SIOCGLIFPHYADDR: 605 if (sc->g_src.s_addr == INADDR_ANY || 606 sc->g_dst.s_addr == INADDR_ANY) { 607 error = EADDRNOTAVAIL; 608 break; 609 } 610 memset(&si, 0, sizeof(si)); 611 si.sin_family = AF_INET; 612 si.sin_len = sizeof(struct sockaddr_in); 613 si.sin_addr.s_addr = sc->g_src.s_addr; 614 memcpy(&lifr->addr, &si, sizeof(si)); 615 si.sin_addr.s_addr = sc->g_dst.s_addr; 616 memcpy(&lifr->dstaddr, &si, sizeof(si)); 617 break; 618 case SIOCGIFPSRCADDR: 619 if (sc->g_src.s_addr == INADDR_ANY) { 620 error = EADDRNOTAVAIL; 621 break; 622 } 623 memset(&si, 0, sizeof(si)); 624 si.sin_family = AF_INET; 625 si.sin_len = sizeof(struct sockaddr_in); 626 si.sin_addr.s_addr = sc->g_src.s_addr; 627 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 628 break; 629 case SIOCGIFPDSTADDR: 630 if (sc->g_dst.s_addr == INADDR_ANY) { 631 error = EADDRNOTAVAIL; 632 break; 633 } 634 memset(&si, 0, sizeof(si)); 635 si.sin_family = AF_INET; 636 si.sin_len = sizeof(struct sockaddr_in); 637 si.sin_addr.s_addr = sc->g_dst.s_addr; 638 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 639 break; 640 default: 641 error = EINVAL; 642 break; 643 } 644 645 crit_exit(); 646 return (error); 647 } 648 649 /* 650 * computes a route to our destination that is not the one 651 * which would be taken by ip_output(), as this one will loop back to 652 * us. If the interface is p2p as a--->b, then a routing entry exists 653 * If we now send a packet to b (e.g. ping b), this will come down here 654 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 655 * if_gre. 656 * Goal here is to compute a route to b that is less specific than 657 * a-->b. We know that this one exists as in normal operation we have 658 * at least a default route which matches. 659 */ 660 static int 661 gre_compute_route(struct gre_softc *sc) 662 { 663 struct route *ro; 664 u_int32_t a, b, c; 665 666 ro = &sc->route; 667 668 memset(ro, 0, sizeof(struct route)); 669 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 670 ro->ro_dst.sa_family = AF_INET; 671 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 672 673 /* 674 * toggle last bit, so our interface is not found, but a less 675 * specific route. I'd rather like to specify a shorter mask, 676 * but this is not possible. Should work though. XXX 677 * there is a simpler way ... 678 */ 679 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 680 a = ntohl(sc->g_dst.s_addr); 681 b = a & 0x01; 682 c = a & 0xfffffffe; 683 b = b ^ 0x01; 684 a = b | c; 685 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 686 = htonl(a); 687 } 688 689 #ifdef DIAGNOSTIC 690 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 691 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 692 #endif 693 694 rtalloc(ro); 695 696 /* 697 * check if this returned a route at all and this route is no 698 * recursion to ourself 699 */ 700 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 701 #ifdef DIAGNOSTIC 702 if (ro->ro_rt == NULL) 703 kprintf(" - no route found!\n"); 704 else 705 kprintf(" - route loops back to ourself!\n"); 706 #endif 707 return EADDRNOTAVAIL; 708 } 709 710 /* 711 * now change it back - else ip_output will just drop 712 * the route and search one to this interface ... 713 */ 714 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 715 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 716 717 #ifdef DIAGNOSTIC 718 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 719 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 720 kprintf("\n"); 721 #endif 722 723 return 0; 724 } 725 726 /* 727 * do a checksum of a buffer - much like in_cksum, which operates on 728 * mbufs. 729 */ 730 u_short 731 gre_in_cksum(u_short *p, u_int len) 732 { 733 u_int sum = 0; 734 int nwords = len >> 1; 735 736 while (nwords-- != 0) 737 sum += *p++; 738 739 if (len & 1) { 740 union { 741 u_short w; 742 u_char c[2]; 743 } u; 744 u.c[0] = *(u_char *)p; 745 u.c[1] = 0; 746 sum += u.w; 747 } 748 749 /* end-around-carry */ 750 sum = (sum >> 16) + (sum & 0xffff); 751 sum += (sum >> 16); 752 return (~sum); 753 } 754 755 static int 756 gremodevent(module_t mod, int type, void *data) 757 { 758 759 switch (type) { 760 case MOD_LOAD: 761 greattach(); 762 break; 763 case MOD_UNLOAD: 764 if_clone_detach(&gre_cloner); 765 766 while (!LIST_EMPTY(&gre_softc_list)) 767 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 768 769 break; 770 } 771 return 0; 772 } 773 774 static moduledata_t gre_mod = { 775 "if_gre", 776 gremodevent, 777 0 778 }; 779 780 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 781 MODULE_VERSION(if_gre, 1); 782