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_inet.h" 50 51 #include <sys/param.h> 52 #include <sys/kernel.h> 53 #include <sys/bus.h> 54 #include <sys/malloc.h> 55 #include <sys/mbuf.h> 56 #include <sys/proc.h> 57 #include <sys/priv.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 #include <sys/thread2.h> 64 65 #include <net/ethernet.h> 66 #include <net/if.h> 67 #include <net/if_types.h> 68 #include <net/ifq_var.h> 69 #include <net/route.h> 70 #include <net/if_clone.h> 71 #include <net/netmsg2.h> 72 #include <net/netisr2.h> 73 74 #ifdef INET 75 #include <netinet/in.h> 76 #include <netinet/in_systm.h> 77 #include <netinet/in_var.h> 78 #include <netinet/ip.h> 79 #include <netinet/ip_gre.h> 80 #include <netinet/ip_var.h> 81 #include <netinet/ip_encap.h> 82 #else 83 #error "Huh? if_gre without inet?" 84 #endif 85 86 #include <net/bpf.h> 87 88 #include <net/net_osdep.h> 89 #include "if_gre.h" 90 91 /* 92 * It is not easy to calculate the right value for a GRE MTU. 93 * We leave this task to the admin and use the same default that 94 * other vendors use. 95 */ 96 #define GREMTU 1476 97 98 #define GRENAME "gre" 99 100 static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation"); 101 102 struct gre_softc_head gre_softc_list; 103 104 static int gre_clone_create(struct if_clone *, int, caddr_t); 105 static int gre_clone_destroy(struct ifnet *); 106 static int gre_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *); 107 static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *, 108 struct rtentry *rt); 109 110 static struct if_clone gre_cloner = IF_CLONE_INITIALIZER("gre", 111 gre_clone_create, gre_clone_destroy, 0, IF_MAXUNIT); 112 113 static int gre_compute_route(struct gre_softc *sc, struct route *); 114 static int gre_check_route(struct gre_softc *sc); 115 116 static void greattach(void); 117 118 #ifdef INET 119 120 extern struct domain inetdomain; 121 122 static const struct protosw in_gre_protosw = 123 { 124 .pr_type = SOCK_RAW, 125 .pr_domain = &inetdomain, 126 .pr_protocol = IPPROTO_GRE, 127 .pr_flags = PR_ATOMIC|PR_ADDR, 128 129 .pr_input = gre_input, 130 .pr_output = rip_output, 131 .pr_ctlinput = rip_ctlinput, 132 .pr_ctloutput = rip_ctloutput, 133 134 .pr_ctlport = cpu0_ctlport, 135 .pr_usrreqs = &rip_usrreqs 136 }; 137 138 static const struct protosw in_mobile_protosw = 139 { 140 .pr_type = SOCK_RAW, 141 .pr_domain = &inetdomain, 142 .pr_protocol = IPPROTO_MOBILE, 143 .pr_flags = PR_ATOMIC|PR_ADDR, 144 145 .pr_input = gre_mobile_input, 146 .pr_output = rip_output, 147 .pr_ctlinput = rip_ctlinput, 148 .pr_ctloutput = rip_ctloutput, 149 150 .pr_ctlport = cpu0_ctlport, 151 .pr_usrreqs = &rip_usrreqs 152 }; 153 154 #endif 155 156 SYSCTL_DECL(_net_link); 157 SYSCTL_NODE(_net_link, IFT_OTHER, gre, CTLFLAG_RW, 0, 158 "Generic Routing Encapsulation"); 159 #ifndef MAX_GRE_NEST 160 /* 161 * This macro controls the default upper limitation on nesting of gre tunnels. 162 * Since, setting a large value to this macro with a careless configuration 163 * may introduce system crash, we don't allow any nestings by default. 164 * If you need to configure nested gre tunnels, you can define this macro 165 * in your kernel configuration file. However, if you do so, please be 166 * careful to configure the tunnels so that it won't make a loop. 167 */ 168 #define MAX_GRE_NEST 1 169 #endif 170 static int max_gre_nesting = MAX_GRE_NEST; 171 SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW, 172 &max_gre_nesting, 0, "Max nested tunnels"); 173 174 /* ARGSUSED */ 175 static void 176 greattach(void) 177 { 178 179 LIST_INIT(&gre_softc_list); 180 if_clone_attach(&gre_cloner); 181 } 182 183 static int 184 gre_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused) 185 { 186 struct gre_softc *sc; 187 188 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 189 memset(sc, 0, sizeof(struct gre_softc)); 190 191 sc->sc_if.if_softc = sc; 192 if_initname(&(sc->sc_if), GRENAME, unit); 193 ifq_set_maxlen(&sc->sc_if.if_snd, IFQ_MAXLEN); 194 sc->sc_if.if_type = IFT_OTHER; 195 sc->sc_if.if_addrlen = 0; 196 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 197 sc->sc_if.if_mtu = GREMTU; 198 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 199 sc->sc_if.if_output = gre_output; 200 sc->sc_if.if_ioctl = gre_ioctl; 201 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 202 sc->g_proto = IPPROTO_GRE; 203 sc->sc_if.if_flags |= IFF_LINK0; 204 sc->encap = NULL; 205 sc->called = 0; 206 sc->route_pcpu = kmalloc(netisr_ncpus * sizeof(struct route), M_GRE, 207 M_WAITOK | M_ZERO); 208 if_attach(&sc->sc_if, NULL); 209 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 210 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 211 return (0); 212 } 213 214 static int 215 gre_clone_destroy(struct ifnet *ifp) 216 { 217 struct gre_softc *sc = ifp->if_softc; 218 int cpu; 219 220 #ifdef INET 221 if (sc->encap != NULL) 222 encap_detach(sc->encap); 223 #endif 224 LIST_REMOVE(sc, sc_list); 225 bpfdetach(ifp); 226 if_detach(ifp); 227 228 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 229 if (sc->route_pcpu[cpu].ro_rt != NULL) { 230 rtfree_async(sc->route_pcpu[cpu].ro_rt); 231 sc->route_pcpu[cpu].ro_rt = NULL; 232 } 233 } 234 kfree(sc->route_pcpu, M_GRE); 235 kfree(sc, M_GRE); 236 237 return 0; 238 } 239 240 /* 241 * The output routine. Takes a packet and encapsulates it in the protocol 242 * given by sc->g_proto. See also RFC 1701 and RFC 2004 243 */ 244 static int 245 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 246 struct rtentry *rt) 247 { 248 int error = 0; 249 struct gre_softc *sc = ifp->if_softc; 250 struct greip *gh; 251 struct ip *ip; 252 u_short etype = 0; 253 struct mobile_h mob_h; 254 struct route *ro; 255 struct sockaddr_in *ro_dst; 256 257 ASSERT_NETISR_NCPUS(mycpuid); 258 259 /* 260 * gre may cause infinite recursion calls when misconfigured. 261 * We'll prevent this by introducing upper limit. 262 */ 263 if (++(sc->called) > max_gre_nesting) { 264 kprintf("%s: gre_output: recursively called too many " 265 "times(%d)\n", if_name(&sc->sc_if), sc->called); 266 m_freem(m); 267 error = EIO; /* is there better errno? */ 268 goto end; 269 } 270 271 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 272 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 273 m_freem(m); 274 error = ENETDOWN; 275 goto end; 276 } 277 278 ro = &sc->route_pcpu[mycpuid]; 279 ro_dst = (struct sockaddr_in *)&ro->ro_dst; 280 if (ro->ro_rt != NULL && 281 ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 282 ro_dst->sin_addr.s_addr != sc->g_dst.s_addr)) { 283 RTFREE(ro->ro_rt); 284 ro->ro_rt = NULL; 285 } 286 if (ro->ro_rt == NULL) { 287 error = gre_compute_route(sc, ro); 288 if (error) { 289 m_freem(m); 290 goto end; 291 } 292 } 293 294 gh = NULL; 295 ip = NULL; 296 297 if (ifp->if_bpf) { 298 bpf_gettoken(); 299 if (ifp->if_bpf) { 300 uint32_t af = dst->sa_family; 301 302 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 303 } 304 bpf_reltoken(); 305 } 306 307 m->m_flags &= ~(M_BCAST|M_MCAST); 308 309 if (sc->g_proto == IPPROTO_MOBILE) { 310 if (dst->sa_family == AF_INET) { 311 struct mbuf *m0; 312 int msiz; 313 314 ip = mtod(m, struct ip *); 315 316 /* 317 * RFC2004 specifies that fragmented datagrams shouldn't 318 * be encapsulated. 319 */ 320 if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 321 m_freem(m); 322 error = EINVAL; /* is there better errno? */ 323 goto end; 324 } 325 memset(&mob_h, 0, MOB_H_SIZ_L); 326 mob_h.proto = (ip->ip_p) << 8; 327 mob_h.odst = ip->ip_dst.s_addr; 328 ip->ip_dst.s_addr = sc->g_dst.s_addr; 329 330 /* 331 * If the packet comes from our host, we only change 332 * the destination address in the IP header. 333 * Else we also need to save and change the source 334 */ 335 if (in_hosteq(ip->ip_src, sc->g_src)) { 336 msiz = MOB_H_SIZ_S; 337 } else { 338 mob_h.proto |= MOB_H_SBIT; 339 mob_h.osrc = ip->ip_src.s_addr; 340 ip->ip_src.s_addr = sc->g_src.s_addr; 341 msiz = MOB_H_SIZ_L; 342 } 343 mob_h.proto = htons(mob_h.proto); 344 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 345 346 if ((m->m_data - msiz) < m->m_pktdat) { 347 /* need new mbuf */ 348 MGETHDR(m0, M_NOWAIT, MT_HEADER); 349 if (m0 == NULL) { 350 m_freem(m); 351 error = ENOBUFS; 352 goto end; 353 } 354 m0->m_next = m; 355 m->m_data += sizeof(struct ip); 356 m->m_len -= sizeof(struct ip); 357 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 358 m0->m_len = msiz + sizeof(struct ip); 359 m0->m_data += max_linkhdr; 360 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 361 sizeof(struct ip)); 362 m = m0; 363 } else { /* we have some space left in the old one */ 364 m->m_data -= msiz; 365 m->m_len += msiz; 366 m->m_pkthdr.len += msiz; 367 bcopy(ip, mtod(m, caddr_t), 368 sizeof(struct ip)); 369 } 370 ip = mtod(m, struct ip *); 371 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 372 ip->ip_len = ntohs(ip->ip_len) + msiz; 373 } else { /* AF_INET */ 374 m_freem(m); 375 error = EINVAL; 376 goto end; 377 } 378 } else if (sc->g_proto == IPPROTO_GRE) { 379 switch (dst->sa_family) { 380 case AF_INET: 381 ip = mtod(m, struct ip *); 382 etype = ETHERTYPE_IP; 383 break; 384 default: 385 m_freem(m); 386 error = EAFNOSUPPORT; 387 goto end; 388 } 389 M_PREPEND(m, sizeof(struct greip), M_NOWAIT); 390 } else { 391 m_freem(m); 392 error = EINVAL; 393 goto end; 394 } 395 396 if (m == NULL) { /* impossible */ 397 error = ENOBUFS; 398 goto end; 399 } 400 401 gh = mtod(m, struct greip *); 402 if (sc->g_proto == IPPROTO_GRE) { 403 /* we don't have any GRE flags for now */ 404 405 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 406 gh->gi_ptype = htons(etype); 407 } 408 409 gh->gi_pr = sc->g_proto; 410 if (sc->g_proto != IPPROTO_MOBILE) { 411 gh->gi_src = sc->g_src; 412 gh->gi_dst = sc->g_dst; 413 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 414 ((struct ip*)gh)->ip_ttl = GRE_TTL; 415 ((struct ip*)gh)->ip_tos = ip->ip_tos; 416 ((struct ip*)gh)->ip_id = ip->ip_id; 417 gh->gi_len = m->m_pkthdr.len; 418 } 419 420 IFNET_STAT_INC(ifp, opackets, 1); 421 IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len); 422 /* send it off */ 423 error = ip_output(m, NULL, ro, IP_DEBUGROUTE, NULL, NULL); 424 end: 425 sc->called = 0; 426 if (error) 427 IFNET_STAT_INC(ifp, oerrors, 1); 428 return (error); 429 } 430 431 static int 432 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 433 struct rtentry *rt) 434 { 435 struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd); 436 int error; 437 438 ifsq_serialize_hw(ifsq); 439 error = gre_output_serialized(ifp, m, dst, rt); 440 ifsq_deserialize_hw(ifsq); 441 442 return error; 443 } 444 445 static int 446 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 447 { 448 struct ifreq *ifr = (struct ifreq *)data; 449 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 450 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 451 struct gre_softc *sc = ifp->if_softc; 452 struct sockaddr_in si; 453 struct sockaddr *sa = NULL; 454 int error; 455 struct sockaddr_in sp, sm, dp, dm; 456 457 error = 0; 458 459 crit_enter(); 460 switch (cmd) { 461 case SIOCSIFADDR: 462 ifp->if_flags |= IFF_UP; 463 break; 464 case SIOCSIFDSTADDR: 465 break; 466 case SIOCSIFFLAGS: 467 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 468 break; 469 if ((ifr->ifr_flags & IFF_LINK0) != 0) 470 sc->g_proto = IPPROTO_GRE; 471 else 472 sc->g_proto = IPPROTO_MOBILE; 473 goto recompute; 474 case SIOCSIFMTU: 475 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 476 break; 477 if (ifr->ifr_mtu < 576) { 478 error = EINVAL; 479 break; 480 } 481 ifp->if_mtu = ifr->ifr_mtu; 482 break; 483 case SIOCGIFMTU: 484 ifr->ifr_mtu = sc->sc_if.if_mtu; 485 break; 486 case SIOCADDMULTI: 487 case SIOCDELMULTI: 488 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 489 break; 490 if (ifr == NULL) { 491 error = EAFNOSUPPORT; 492 break; 493 } 494 switch (ifr->ifr_addr.sa_family) { 495 #ifdef INET 496 case AF_INET: 497 break; 498 #endif 499 default: 500 error = EAFNOSUPPORT; 501 break; 502 } 503 break; 504 case GRESPROTO: 505 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 506 break; 507 sc->g_proto = ifr->ifr_flags; 508 switch (sc->g_proto) { 509 case IPPROTO_GRE: 510 ifp->if_flags |= IFF_LINK0; 511 break; 512 case IPPROTO_MOBILE: 513 ifp->if_flags &= ~IFF_LINK0; 514 break; 515 default: 516 error = EPROTONOSUPPORT; 517 break; 518 } 519 goto recompute; 520 case GREGPROTO: 521 ifr->ifr_flags = sc->g_proto; 522 break; 523 case GRESADDRS: 524 case GRESADDRD: 525 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 526 break; 527 /* 528 * set tunnel endpoints, compute a less specific route 529 * to the remote end and mark if as up 530 */ 531 sa = &ifr->ifr_addr; 532 if (cmd == GRESADDRS) 533 sc->g_src = (satosin(sa))->sin_addr; 534 if (cmd == GRESADDRD) 535 sc->g_dst = (satosin(sa))->sin_addr; 536 recompute: 537 #ifdef INET 538 if (sc->encap != NULL) { 539 encap_detach(sc->encap); 540 sc->encap = NULL; 541 } 542 #endif 543 if ((sc->g_src.s_addr != INADDR_ANY) && 544 (sc->g_dst.s_addr != INADDR_ANY)) { 545 bzero(&sp, sizeof(sp)); 546 bzero(&sm, sizeof(sm)); 547 bzero(&dp, sizeof(dp)); 548 bzero(&dm, sizeof(dm)); 549 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 550 sizeof(struct sockaddr_in); 551 sp.sin_family = sm.sin_family = dp.sin_family = 552 dm.sin_family = AF_INET; 553 sp.sin_addr = sc->g_src; 554 dp.sin_addr = sc->g_dst; 555 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 556 INADDR_BROADCAST; 557 #ifdef INET 558 sc->encap = encap_attach(AF_INET, sc->g_proto, 559 sintosa(&sp), sintosa(&sm), sintosa(&dp), 560 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 561 &in_gre_protosw : &in_mobile_protosw, sc); 562 if (sc->encap == NULL) 563 kprintf("%s: unable to attach encap\n", 564 if_name(&sc->sc_if)); 565 #endif 566 ifnet_deserialize_all(ifp); 567 error = gre_check_route(sc); 568 ifnet_serialize_all(ifp); 569 if (!error) 570 ifp->if_flags |= IFF_RUNNING; 571 else 572 ifp->if_flags &= ~IFF_RUNNING; 573 } 574 break; 575 case GREGADDRS: 576 memset(&si, 0, sizeof(si)); 577 si.sin_family = AF_INET; 578 si.sin_len = sizeof(struct sockaddr_in); 579 si.sin_addr.s_addr = sc->g_src.s_addr; 580 sa = sintosa(&si); 581 ifr->ifr_addr = *sa; 582 break; 583 case GREGADDRD: 584 memset(&si, 0, sizeof(si)); 585 si.sin_family = AF_INET; 586 si.sin_len = sizeof(struct sockaddr_in); 587 si.sin_addr.s_addr = sc->g_dst.s_addr; 588 sa = sintosa(&si); 589 ifr->ifr_addr = *sa; 590 break; 591 case SIOCSIFPHYADDR: 592 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 593 break; 594 if (aifr->ifra_addr.sin_family != AF_INET || 595 aifr->ifra_dstaddr.sin_family != AF_INET) { 596 error = EAFNOSUPPORT; 597 break; 598 } 599 if (aifr->ifra_addr.sin_len != sizeof(si) || 600 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 601 error = EINVAL; 602 break; 603 } 604 sc->g_src = aifr->ifra_addr.sin_addr; 605 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 606 goto recompute; 607 case SIOCSLIFPHYADDR: 608 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 609 break; 610 if (lifr->addr.ss_family != AF_INET || 611 lifr->dstaddr.ss_family != AF_INET) { 612 error = EAFNOSUPPORT; 613 break; 614 } 615 if (lifr->addr.ss_len != sizeof(si) || 616 lifr->dstaddr.ss_len != sizeof(si)) { 617 error = EINVAL; 618 break; 619 } 620 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 621 sc->g_dst = 622 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 623 goto recompute; 624 case SIOCDIFPHYADDR: 625 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 626 break; 627 sc->g_src.s_addr = INADDR_ANY; 628 sc->g_dst.s_addr = INADDR_ANY; 629 goto recompute; 630 case SIOCGLIFPHYADDR: 631 if (sc->g_src.s_addr == INADDR_ANY || 632 sc->g_dst.s_addr == INADDR_ANY) { 633 error = EADDRNOTAVAIL; 634 break; 635 } 636 memset(&si, 0, sizeof(si)); 637 si.sin_family = AF_INET; 638 si.sin_len = sizeof(struct sockaddr_in); 639 si.sin_addr.s_addr = sc->g_src.s_addr; 640 memcpy(&lifr->addr, &si, sizeof(si)); 641 si.sin_addr.s_addr = sc->g_dst.s_addr; 642 memcpy(&lifr->dstaddr, &si, sizeof(si)); 643 break; 644 case SIOCGIFPSRCADDR: 645 if (sc->g_src.s_addr == INADDR_ANY) { 646 error = EADDRNOTAVAIL; 647 break; 648 } 649 memset(&si, 0, sizeof(si)); 650 si.sin_family = AF_INET; 651 si.sin_len = sizeof(struct sockaddr_in); 652 si.sin_addr.s_addr = sc->g_src.s_addr; 653 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 654 break; 655 case SIOCGIFPDSTADDR: 656 if (sc->g_dst.s_addr == INADDR_ANY) { 657 error = EADDRNOTAVAIL; 658 break; 659 } 660 memset(&si, 0, sizeof(si)); 661 si.sin_family = AF_INET; 662 si.sin_len = sizeof(struct sockaddr_in); 663 si.sin_addr.s_addr = sc->g_dst.s_addr; 664 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 665 break; 666 default: 667 error = EINVAL; 668 break; 669 } 670 671 crit_exit(); 672 return (error); 673 } 674 675 /* 676 * computes a route to our destination that is not the one 677 * which would be taken by ip_output(), as this one will loop back to 678 * us. If the interface is p2p as a--->b, then a routing entry exists 679 * If we now send a packet to b (e.g. ping b), this will come down here 680 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 681 * if_gre. 682 * Goal here is to compute a route to b that is less specific than 683 * a-->b. We know that this one exists as in normal operation we have 684 * at least a default route which matches. 685 */ 686 static int 687 gre_compute_route(struct gre_softc *sc, struct route *ro) 688 { 689 #ifdef DIAGNOSTIC 690 char abuf[INET_ADDRSTRLEN]; 691 #endif 692 u_int32_t a, b, c; 693 694 ASSERT_NETISR_NCPUS(mycpuid); 695 KASSERT(ro == &sc->route_pcpu[mycpuid], ("route mismatch")); 696 KASSERT(ro->ro_rt == NULL, ("rtentry not freed")); 697 698 memset(ro, 0, sizeof(struct route)); 699 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 700 ro->ro_dst.sa_family = AF_INET; 701 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 702 703 /* 704 * toggle last bit, so our interface is not found, but a less 705 * specific route. I'd rather like to specify a shorter mask, 706 * but this is not possible. Should work though. XXX 707 * there is a simpler way ... 708 */ 709 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 710 a = ntohl(sc->g_dst.s_addr); 711 b = a & 0x01; 712 c = a & 0xfffffffe; 713 b = b ^ 0x01; 714 a = b | c; 715 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 716 = htonl(a); 717 } 718 719 #ifdef DIAGNOSTIC 720 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 721 kinet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr, abuf)); 722 #endif 723 724 rtalloc(ro); 725 726 /* 727 * check if this returned a route at all and this route is no 728 * recursion to ourself 729 */ 730 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 731 #ifdef DIAGNOSTIC 732 if (ro->ro_rt == NULL) 733 kprintf(" - no route found!\n"); 734 else 735 kprintf(" - route loops back to ourself!\n"); 736 #endif 737 return EADDRNOTAVAIL; 738 } 739 740 /* 741 * now change it back - else ip_output will just drop 742 * the route and search one to this interface ... 743 */ 744 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 745 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 746 747 #ifdef DIAGNOSTIC 748 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 749 kinet_ntoa( 750 ((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr, abuf)); 751 kprintf("\n"); 752 #endif 753 754 return 0; 755 } 756 757 static void 758 gre_check_route_handler(netmsg_t msg) 759 { 760 struct gre_softc *sc = msg->base.lmsg.u.ms_resultp; 761 struct route *ro; 762 int error; 763 764 ASSERT_NETISR0; 765 766 ro = &sc->route_pcpu[mycpuid]; 767 if (ro->ro_rt != NULL) { 768 RTFREE(ro->ro_rt); 769 ro->ro_rt = NULL; 770 } 771 error = gre_compute_route(sc, ro); 772 773 netisr_replymsg(&msg->base, error); 774 } 775 776 static int 777 gre_check_route(struct gre_softc *sc) 778 { 779 struct netmsg_base msg; 780 781 netmsg_init(&msg, NULL, &curthread->td_msgport, MSGF_PRIORITY, 782 gre_check_route_handler); 783 msg.lmsg.u.ms_resultp = sc; 784 785 return (netisr_domsg(&msg, 0)); 786 } 787 788 /* 789 * do a checksum of a buffer - much like in_cksum, which operates on 790 * mbufs. 791 */ 792 u_short 793 gre_in_cksum(u_short *p, u_int len) 794 { 795 u_int sum = 0; 796 int nwords = len >> 1; 797 798 while (nwords-- != 0) 799 sum += *p++; 800 801 if (len & 1) { 802 union { 803 u_short w; 804 u_char c[2]; 805 } u; 806 u.c[0] = *(u_char *)p; 807 u.c[1] = 0; 808 sum += u.w; 809 } 810 811 /* end-around-carry */ 812 sum = (sum >> 16) + (sum & 0xffff); 813 sum += (sum >> 16); 814 return (~sum); 815 } 816 817 static int 818 gremodevent(module_t mod, int type, void *data) 819 { 820 821 switch (type) { 822 case MOD_LOAD: 823 greattach(); 824 break; 825 case MOD_UNLOAD: 826 if_clone_detach(&gre_cloner); 827 828 while (!LIST_EMPTY(&gre_softc_list)) 829 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 830 831 break; 832 } 833 return 0; 834 } 835 836 static moduledata_t gre_mod = { 837 "if_gre", 838 gremodevent, 839 0 840 }; 841 842 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 843 MODULE_VERSION(if_gre, 1); 844