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sys/net/if_gre.c
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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 #include "opt_ns.h" 52 53 #include <sys/param.h> 54 #include <sys/kernel.h> 55 #include <sys/malloc.h> 56 #include <sys/mbuf.h> 57 #include <sys/proc.h> 58 #include <sys/protosw.h> 59 #include <machine/bus.h> 60 #include <sys/rman.h> 61 #include <sys/socket.h> 62 #include <sys/sockio.h> 63 #include <sys/sysctl.h> 64 #include <sys/systm.h> 65 66 #include <net/ethernet.h> 67 #include <net/if.h> 68 #include <net/if_types.h> 69 #include <net/route.h> 70 71 #ifdef INET 72 #include <netinet/in.h> 73 #include <netinet/in_systm.h> 74 #include <netinet/in_var.h> 75 #include <netinet/ip.h> 76 #include <netinet/ip_gre.h> 77 #include <netinet/ip_var.h> 78 #include <netinet/ip_encap.h> 79 #else 80 #error "Huh? if_gre without inet?" 81 #endif 82 83 #include <net/bpf.h> 84 85 #include <net/net_osdep.h> 86 #include <net/if_gre.h> 87 88 /* 89 * It is not easy to calculate the right value for a GRE MTU. 90 * We leave this task to the admin and use the same default that 91 * other vendors use. 92 */ 93 #define GREMTU 1476 94 95 #define GRENAME "gre" 96 #define GRE_MAXUNIT 0x7fff 97 98 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 99 static struct rman greunits[1]; 100 101 struct gre_softc_head gre_softc_list; 102 103 static int gre_clone_create(struct if_clone *, int *); 104 static void gre_clone_destroy(struct ifnet *); 105 static int gre_ioctl(struct ifnet *, u_long, caddr_t); 106 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 107 struct rtentry *rt); 108 109 static struct if_clone gre_cloner = 110 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 111 112 static int gre_compute_route(struct gre_softc *sc); 113 114 static void greattach(void); 115 116 #ifdef INET 117 extern struct domain inetdomain; 118 static const struct protosw in_gre_protosw = 119 { SOCK_RAW, &inetdomain, IPPROTO_GRE, PR_ATOMIC|PR_ADDR, 120 gre_input, rip_output, rip_ctlinput, rip_ctloutput, 121 0, 122 0, 0, 0, 0, 123 &rip_usrreqs 124 }; 125 static const struct protosw in_mobile_protosw = 126 { SOCK_RAW, &inetdomain, IPPROTO_MOBILE, PR_ATOMIC|PR_ADDR, 127 gre_mobile_input, rip_output, rip_ctlinput, rip_ctloutput, 128 0, 129 0, 0, 0, 0, 130 &rip_usrreqs 131 }; 132 #endif 133 134 SYSCTL_DECL(_net_link); 135 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 136 "Generic Routing Encapsulation"); 137 #ifndef MAX_GRE_NEST 138 /* 139 * This macro controls the default upper limitation on nesting of gre tunnels. 140 * Since, setting a large value to this macro with a careless configuration 141 * may introduce system crash, we don't allow any nestings by default. 142 * If you need to configure nested gre tunnels, you can define this macro 143 * in your kernel configuration file. However, if you do so, please be 144 * careful to configure the tunnels so that it won't make a loop. 145 */ 146 #define MAX_GRE_NEST 1 147 #endif 148 static int max_gre_nesting = MAX_GRE_NEST; 149 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 150 &max_gre_nesting, 0, "Max nested tunnels"); 151 152 /* ARGSUSED */ 153 static void 154 greattach(void) 155 { 156 157 LIST_INIT(&gre_softc_list); 158 if_clone_attach(&gre_cloner); 159 } 160 161 static int 162 gre_clone_create(ifc, unit) 163 struct if_clone *ifc; 164 int *unit; 165 { 166 struct resource *r; 167 struct gre_softc *sc; 168 169 if (*unit > GRE_MAXUNIT) 170 return (ENXIO); 171 172 if (*unit < 0) { 173 r = rman_reserve_resource(greunits, 0, GRE_MAXUNIT, 1, 174 RF_ALLOCATED | RF_ACTIVE, NULL); 175 if (r == NULL) 176 return (ENOSPC); 177 *unit = rman_get_start(r); 178 } else { 179 r = rman_reserve_resource(greunits, *unit, *unit, 1, 180 RF_ALLOCATED | RF_ACTIVE, NULL); 181 if (r == NULL) 182 return (EEXIST); 183 } 184 185 sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 186 memset(sc, 0, sizeof(struct gre_softc)); 187 188 sc->sc_if.if_name = GRENAME; 189 sc->sc_if.if_softc = sc; 190 sc->sc_if.if_unit = *unit; 191 sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN; 192 sc->sc_if.if_type = IFT_OTHER; 193 sc->sc_if.if_addrlen = 0; 194 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 195 sc->sc_if.if_mtu = GREMTU; 196 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 197 sc->sc_if.if_output = gre_output; 198 sc->sc_if.if_ioctl = gre_ioctl; 199 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 200 sc->g_proto = IPPROTO_GRE; 201 sc->sc_if.if_flags |= IFF_LINK0; 202 sc->encap = NULL; 203 sc->called = 0; 204 sc->r_unit = r; 205 if_attach(&sc->sc_if); 206 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 207 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 208 return (0); 209 } 210 211 static void 212 gre_clone_destroy(ifp) 213 struct ifnet *ifp; 214 { 215 int err; 216 struct gre_softc *sc = ifp->if_softc; 217 218 #ifdef INET 219 if (sc->encap != NULL) 220 encap_detach(sc->encap); 221 #endif 222 LIST_REMOVE(sc, sc_list); 223 bpfdetach(ifp); 224 if_detach(ifp); 225 226 err = rman_release_resource(sc->r_unit); 227 KASSERT(err == 0, ("Unexpected error freeing resource")); 228 229 free(sc, M_GRE); 230 } 231 232 /* 233 * The output routine. Takes a packet and encapsulates it in the protocol 234 * given by sc->g_proto. See also RFC 1701 and RFC 2004 235 */ 236 static int 237 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 238 struct rtentry *rt) 239 { 240 int error = 0; 241 struct gre_softc *sc = ifp->if_softc; 242 struct greip *gh; 243 struct ip *ip; 244 u_char osrc; 245 u_short etype = 0; 246 struct mobile_h mob_h; 247 248 /* 249 * gre may cause infinite recursion calls when misconfigured. 250 * We'll prevent this by introducing upper limit. 251 */ 252 if (++(sc->called) > max_gre_nesting) { 253 printf("%s: gre_output: recursively called too many " 254 "times(%d)\n", if_name(&sc->sc_if), sc->called); 255 m_freem(m); 256 error = EIO; /* is there better errno? */ 257 goto end; 258 } 259 260 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 261 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 262 m_freem(m); 263 error = ENETDOWN; 264 goto end; 265 } 266 267 gh = NULL; 268 ip = NULL; 269 osrc = 0; 270 271 if (ifp->if_bpf) { 272 /* see comment of other if_foo.c files */ 273 struct mbuf m0; 274 u_int32_t af = dst->sa_family; 275 276 m0.m_next = m; 277 m0.m_len = 4; 278 m0.m_data = (char *)⁡ 279 280 bpf_mtap(ifp, &m0); 281 } 282 283 m->m_flags &= ~(M_BCAST|M_MCAST); 284 285 if (sc->g_proto == IPPROTO_MOBILE) { 286 if (dst->sa_family == AF_INET) { 287 struct mbuf *m0; 288 int msiz; 289 290 ip = mtod(m, struct ip *); 291 292 /* 293 * RFC2004 specifies that fragmented diagrams shouldn't 294 * be encapsulated. 295 */ 296 if ((ip->ip_off & IP_MF) != 0) { 297 IF_DROP(&ifp->if_snd); 298 m_freem(m); 299 error = EINVAL; /* is there better errno? */ 300 goto end; 301 } 302 memset(&mob_h, 0, MOB_H_SIZ_L); 303 mob_h.proto = (ip->ip_p) << 8; 304 mob_h.odst = ip->ip_dst.s_addr; 305 ip->ip_dst.s_addr = sc->g_dst.s_addr; 306 307 /* 308 * If the packet comes from our host, we only change 309 * the destination address in the IP header. 310 * Else we also need to save and change the source 311 */ 312 if (in_hosteq(ip->ip_src, sc->g_src)) { 313 msiz = MOB_H_SIZ_S; 314 } else { 315 mob_h.proto |= MOB_H_SBIT; 316 mob_h.osrc = ip->ip_src.s_addr; 317 ip->ip_src.s_addr = sc->g_src.s_addr; 318 msiz = MOB_H_SIZ_L; 319 } 320 mob_h.proto = htons(mob_h.proto); 321 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 322 323 if ((m->m_data - msiz) < m->m_pktdat) { 324 /* need new mbuf */ 325 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 326 if (m0 == NULL) { 327 IF_DROP(&ifp->if_snd); 328 m_freem(m); 329 error = ENOBUFS; 330 goto end; 331 } 332 m0->m_next = m; 333 m->m_data += sizeof(struct ip); 334 m->m_len -= sizeof(struct ip); 335 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 336 m0->m_len = msiz + sizeof(struct ip); 337 m0->m_data += max_linkhdr; 338 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 339 sizeof(struct ip)); 340 m = m0; 341 } else { /* we have some space left in the old one */ 342 m->m_data -= msiz; 343 m->m_len += msiz; 344 m->m_pkthdr.len += msiz; 345 bcopy(ip, mtod(m, caddr_t), 346 sizeof(struct ip)); 347 } 348 ip = mtod(m, struct ip *); 349 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 350 ip->ip_len = ntohs(ip->ip_len) + msiz; 351 } else { /* AF_INET */ 352 IF_DROP(&ifp->if_snd); 353 m_freem(m); 354 error = EINVAL; 355 goto end; 356 } 357 } else if (sc->g_proto == IPPROTO_GRE) { 358 switch (dst->sa_family) { 359 case AF_INET: 360 ip = mtod(m, struct ip *); 361 etype = ETHERTYPE_IP; 362 break; 363 #ifdef NETATALK 364 case AF_APPLETALK: 365 etype = ETHERTYPE_ATALK; 366 break; 367 #endif 368 #ifdef NS 369 case AF_NS: 370 etype = ETHERTYPE_NS; 371 break; 372 #endif 373 default: 374 IF_DROP(&ifp->if_snd); 375 m_freem(m); 376 error = EAFNOSUPPORT; 377 goto end; 378 } 379 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 380 } else { 381 IF_DROP(&ifp->if_snd); 382 m_freem(m); 383 error = EINVAL; 384 goto end; 385 } 386 387 if (m == NULL) { /* impossible */ 388 IF_DROP(&ifp->if_snd); 389 error = ENOBUFS; 390 goto end; 391 } 392 393 gh = mtod(m, struct greip *); 394 if (sc->g_proto == IPPROTO_GRE) { 395 /* we don't have any GRE flags for now */ 396 397 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 398 gh->gi_ptype = htons(etype); 399 } 400 401 gh->gi_pr = sc->g_proto; 402 if (sc->g_proto != IPPROTO_MOBILE) { 403 gh->gi_src = sc->g_src; 404 gh->gi_dst = sc->g_dst; 405 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 406 ((struct ip*)gh)->ip_ttl = GRE_TTL; 407 ((struct ip*)gh)->ip_tos = ip->ip_tos; 408 ((struct ip*)gh)->ip_id = ip->ip_id; 409 gh->gi_len = m->m_pkthdr.len; 410 } 411 412 ifp->if_opackets++; 413 ifp->if_obytes += m->m_pkthdr.len; 414 /* send it off */ 415 error = ip_output(m, NULL, &sc->route, 0, NULL, NULL); 416 end: 417 sc->called = 0; 418 if (error) 419 ifp->if_oerrors++; 420 return (error); 421 } 422 423 static int 424 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 425 { 426 struct ifreq *ifr = (struct ifreq *)data; 427 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 428 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 429 struct gre_softc *sc = ifp->if_softc; 430 int s; 431 struct sockaddr_in si; 432 struct sockaddr *sa = NULL; 433 int error; 434 struct sockaddr_in sp, sm, dp, dm; 435 436 error = 0; 437 438 s = splnet(); 439 switch (cmd) { 440 case SIOCSIFADDR: 441 ifp->if_flags |= IFF_UP; 442 break; 443 case SIOCSIFDSTADDR: 444 break; 445 case SIOCSIFFLAGS: 446 if ((error = suser(curproc)) != 0) 447 break; 448 if ((ifr->ifr_flags & IFF_LINK0) != 0) 449 sc->g_proto = IPPROTO_GRE; 450 else 451 sc->g_proto = IPPROTO_MOBILE; 452 goto recompute; 453 case SIOCSIFMTU: 454 if ((error = suser(curproc)) != 0) 455 break; 456 if (ifr->ifr_mtu < 576) { 457 error = EINVAL; 458 break; 459 } 460 ifp->if_mtu = ifr->ifr_mtu; 461 break; 462 case SIOCGIFMTU: 463 ifr->ifr_mtu = sc->sc_if.if_mtu; 464 break; 465 case SIOCADDMULTI: 466 case SIOCDELMULTI: 467 if ((error = suser(curproc)) != 0) 468 break; 469 if (ifr == 0) { 470 error = EAFNOSUPPORT; 471 break; 472 } 473 switch (ifr->ifr_addr.sa_family) { 474 #ifdef INET 475 case AF_INET: 476 break; 477 #endif 478 default: 479 error = EAFNOSUPPORT; 480 break; 481 } 482 break; 483 case GRESPROTO: 484 if ((error = suser(curproc)) != 0) 485 break; 486 sc->g_proto = ifr->ifr_flags; 487 switch (sc->g_proto) { 488 case IPPROTO_GRE: 489 ifp->if_flags |= IFF_LINK0; 490 break; 491 case IPPROTO_MOBILE: 492 ifp->if_flags &= ~IFF_LINK0; 493 break; 494 default: 495 error = EPROTONOSUPPORT; 496 break; 497 } 498 goto recompute; 499 case GREGPROTO: 500 ifr->ifr_flags = sc->g_proto; 501 break; 502 case GRESADDRS: 503 case GRESADDRD: 504 if ((error = suser(curproc)) != 0) 505 break; 506 /* 507 * set tunnel endpoints, compute a less specific route 508 * to the remote end and mark if as up 509 */ 510 sa = &ifr->ifr_addr; 511 if (cmd == GRESADDRS) 512 sc->g_src = (satosin(sa))->sin_addr; 513 if (cmd == GRESADDRD) 514 sc->g_dst = (satosin(sa))->sin_addr; 515 recompute: 516 #ifdef INET 517 if (sc->encap != NULL) { 518 encap_detach(sc->encap); 519 sc->encap = NULL; 520 } 521 #endif 522 if ((sc->g_src.s_addr != INADDR_ANY) && 523 (sc->g_dst.s_addr != INADDR_ANY)) { 524 bzero(&sp, sizeof(sp)); 525 bzero(&sm, sizeof(sm)); 526 bzero(&dp, sizeof(dp)); 527 bzero(&dm, sizeof(dm)); 528 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 529 sizeof(struct sockaddr_in); 530 sp.sin_family = sm.sin_family = dp.sin_family = 531 dm.sin_family = AF_INET; 532 sp.sin_addr = sc->g_src; 533 dp.sin_addr = sc->g_dst; 534 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 535 INADDR_BROADCAST; 536 #ifdef INET 537 sc->encap = encap_attach(AF_INET, sc->g_proto, 538 sintosa(&sp), sintosa(&sm), sintosa(&dp), 539 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 540 &in_gre_protosw : &in_mobile_protosw, sc); 541 if (sc->encap == NULL) 542 printf("%s: unable to attach encap\n", 543 if_name(&sc->sc_if)); 544 #endif 545 if (sc->route.ro_rt != 0) /* free old route */ 546 RTFREE(sc->route.ro_rt); 547 if (gre_compute_route(sc) == 0) 548 ifp->if_flags |= IFF_RUNNING; 549 else 550 ifp->if_flags &= ~IFF_RUNNING; 551 } 552 break; 553 case GREGADDRS: 554 memset(&si, 0, sizeof(si)); 555 si.sin_family = AF_INET; 556 si.sin_len = sizeof(struct sockaddr_in); 557 si.sin_addr.s_addr = sc->g_src.s_addr; 558 sa = sintosa(&si); 559 ifr->ifr_addr = *sa; 560 break; 561 case GREGADDRD: 562 memset(&si, 0, sizeof(si)); 563 si.sin_family = AF_INET; 564 si.sin_len = sizeof(struct sockaddr_in); 565 si.sin_addr.s_addr = sc->g_dst.s_addr; 566 sa = sintosa(&si); 567 ifr->ifr_addr = *sa; 568 break; 569 case SIOCSIFPHYADDR: 570 if ((error = suser(curproc)) != 0) 571 break; 572 if (aifr->ifra_addr.sin_family != AF_INET || 573 aifr->ifra_dstaddr.sin_family != AF_INET) { 574 error = EAFNOSUPPORT; 575 break; 576 } 577 if (aifr->ifra_addr.sin_len != sizeof(si) || 578 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 579 error = EINVAL; 580 break; 581 } 582 sc->g_src = aifr->ifra_addr.sin_addr; 583 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 584 goto recompute; 585 case SIOCSLIFPHYADDR: 586 if ((error = suser(curproc)) != 0) 587 break; 588 if (lifr->addr.ss_family != AF_INET || 589 lifr->dstaddr.ss_family != AF_INET) { 590 error = EAFNOSUPPORT; 591 break; 592 } 593 if (lifr->addr.ss_len != sizeof(si) || 594 lifr->dstaddr.ss_len != sizeof(si)) { 595 error = EINVAL; 596 break; 597 } 598 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 599 sc->g_dst = 600 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 601 goto recompute; 602 case SIOCDIFPHYADDR: 603 if ((error = suser(curproc)) != 0) 604 break; 605 sc->g_src.s_addr = INADDR_ANY; 606 sc->g_dst.s_addr = INADDR_ANY; 607 goto recompute; 608 case SIOCGLIFPHYADDR: 609 if (sc->g_src.s_addr == INADDR_ANY || 610 sc->g_dst.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 memcpy(&lifr->addr, &si, sizeof(si)); 619 si.sin_addr.s_addr = sc->g_dst.s_addr; 620 memcpy(&lifr->dstaddr, &si, sizeof(si)); 621 break; 622 case SIOCGIFPSRCADDR: 623 if (sc->g_src.s_addr == INADDR_ANY) { 624 error = EADDRNOTAVAIL; 625 break; 626 } 627 memset(&si, 0, sizeof(si)); 628 si.sin_family = AF_INET; 629 si.sin_len = sizeof(struct sockaddr_in); 630 si.sin_addr.s_addr = sc->g_src.s_addr; 631 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 632 break; 633 case SIOCGIFPDSTADDR: 634 if (sc->g_dst.s_addr == INADDR_ANY) { 635 error = EADDRNOTAVAIL; 636 break; 637 } 638 memset(&si, 0, sizeof(si)); 639 si.sin_family = AF_INET; 640 si.sin_len = sizeof(struct sockaddr_in); 641 si.sin_addr.s_addr = sc->g_dst.s_addr; 642 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 643 break; 644 default: 645 error = EINVAL; 646 break; 647 } 648 649 splx(s); 650 return (error); 651 } 652 653 /* 654 * computes a route to our destination that is not the one 655 * which would be taken by ip_output(), as this one will loop back to 656 * us. If the interface is p2p as a--->b, then a routing entry exists 657 * If we now send a packet to b (e.g. ping b), this will come down here 658 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 659 * if_gre. 660 * Goal here is to compute a route to b that is less specific than 661 * a-->b. We know that this one exists as in normal operation we have 662 * at least a default route which matches. 663 */ 664 static int 665 gre_compute_route(struct gre_softc *sc) 666 { 667 struct route *ro; 668 u_int32_t a, b, c; 669 670 ro = &sc->route; 671 672 memset(ro, 0, sizeof(struct route)); 673 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 674 ro->ro_dst.sa_family = AF_INET; 675 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 676 677 /* 678 * toggle last bit, so our interface is not found, but a less 679 * specific route. I'd rather like to specify a shorter mask, 680 * but this is not possible. Should work though. XXX 681 * there is a simpler way ... 682 */ 683 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 684 a = ntohl(sc->g_dst.s_addr); 685 b = a & 0x01; 686 c = a & 0xfffffffe; 687 b = b ^ 0x01; 688 a = b | c; 689 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 690 = htonl(a); 691 } 692 693 #ifdef DIAGNOSTIC 694 printf("%s: searching a route to %s", if_name(&sc->sc_if), 695 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 696 #endif 697 698 rtalloc(ro); 699 700 /* 701 * check if this returned a route at all and this route is no 702 * recursion to ourself 703 */ 704 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 705 #ifdef DIAGNOSTIC 706 if (ro->ro_rt == NULL) 707 printf(" - no route found!\n"); 708 else 709 printf(" - route loops back to ourself!\n"); 710 #endif 711 return EADDRNOTAVAIL; 712 } 713 714 /* 715 * now change it back - else ip_output will just drop 716 * the route and search one to this interface ... 717 */ 718 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 719 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 720 721 #ifdef DIAGNOSTIC 722 printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 723 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 724 printf("\n"); 725 #endif 726 727 return 0; 728 } 729 730 /* 731 * do a checksum of a buffer - much like in_cksum, which operates on 732 * mbufs. 733 */ 734 u_short 735 gre_in_cksum(u_short *p, u_int len) 736 { 737 u_int sum = 0; 738 int nwords = len >> 1; 739 740 while (nwords-- != 0) 741 sum += *p++; 742 743 if (len & 1) { 744 union { 745 u_short w; 746 u_char c[2]; 747 } u; 748 u.c[0] = *(u_char *)p; 749 u.c[1] = 0; 750 sum += u.w; 751 } 752 753 /* end-around-carry */ 754 sum = (sum >> 16) + (sum & 0xffff); 755 sum += (sum >> 16); 756 return (~sum); 757 } 758 759 static int 760 gremodevent(module_t mod, int type, void *data) 761 { 762 int err; 763 764 switch (type) { 765 case MOD_LOAD: 766 greunits->rm_type = RMAN_ARRAY; 767 greunits->rm_descr = "configurable if_gre units"; 768 err = rman_init(greunits); 769 if (err != 0) 770 return (err); 771 err = rman_manage_region(greunits, 0, GRE_MAXUNIT); 772 if (err != 0) { 773 printf("%s: greunits: rman_manage_region: Failed %d\n", 774 GRENAME, err); 775 rman_fini(greunits); 776 return (err); 777 } 778 greattach(); 779 break; 780 case MOD_UNLOAD: 781 if_clone_detach(&gre_cloner); 782 783 while (!LIST_EMPTY(&gre_softc_list)) 784 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 785 786 err = rman_fini(greunits); 787 if (err != 0) 788 return (err); 789 790 break; 791 } 792 return 0; 793 } 794 795 static moduledata_t gre_mod = { 796 "if_gre", 797 gremodevent, 798 0 799 }; 800 801 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 802 MODULE_VERSION(if_gre, 1);
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