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, 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 = NULL, 132 .pr_ctloutput = rip_ctloutput, 133 134 .pr_ctlport = NULL, 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 = NULL, 148 .pr_ctloutput = rip_ctloutput, 149 150 .pr_ctlport = NULL, 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, 185 caddr_t params __unused, caddr_t data __unused) 186 { 187 struct gre_softc *sc; 188 189 sc = kmalloc(sizeof(struct gre_softc), M_GRE, M_WAITOK); 190 memset(sc, 0, sizeof(struct gre_softc)); 191 192 sc->sc_if.if_softc = sc; 193 if_initname(&(sc->sc_if), GRENAME, unit); 194 ifq_set_maxlen(&sc->sc_if.if_snd, IFQ_MAXLEN); 195 sc->sc_if.if_type = IFT_OTHER; 196 sc->sc_if.if_addrlen = 0; 197 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 198 sc->sc_if.if_mtu = GREMTU; 199 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 200 sc->sc_if.if_output = gre_output; 201 sc->sc_if.if_ioctl = gre_ioctl; 202 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 203 sc->g_proto = IPPROTO_GRE; 204 sc->sc_if.if_flags |= IFF_LINK0; 205 sc->encap = NULL; 206 sc->called = 0; 207 sc->route_pcpu = kmalloc(netisr_ncpus * sizeof(struct route), M_GRE, 208 M_WAITOK | M_ZERO); 209 if_attach(&sc->sc_if, NULL); 210 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 211 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 212 return (0); 213 } 214 215 static int 216 gre_clone_destroy(struct ifnet *ifp) 217 { 218 struct gre_softc *sc = ifp->if_softc; 219 int cpu; 220 221 #ifdef INET 222 if (sc->encap != NULL) 223 encap_detach(sc->encap); 224 #endif 225 LIST_REMOVE(sc, sc_list); 226 bpfdetach(ifp); 227 if_detach(ifp); 228 229 for (cpu = 0; cpu < netisr_ncpus; ++cpu) { 230 if (sc->route_pcpu[cpu].ro_rt != NULL) { 231 rtfree_async(sc->route_pcpu[cpu].ro_rt); 232 sc->route_pcpu[cpu].ro_rt = NULL; 233 } 234 } 235 kfree(sc->route_pcpu, M_GRE); 236 kfree(sc, M_GRE); 237 238 return 0; 239 } 240 241 /* 242 * The output routine. Takes a packet and encapsulates it in the protocol 243 * given by sc->g_proto. See also RFC 1701 and RFC 2004 244 */ 245 static int 246 gre_output_serialized(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 247 struct rtentry *rt) 248 { 249 int error = 0; 250 struct gre_softc *sc = ifp->if_softc; 251 struct greip *gh; 252 struct ip *ip; 253 u_short etype = 0; 254 struct mobile_h mob_h; 255 struct route *ro; 256 struct sockaddr_in *ro_dst; 257 258 ASSERT_NETISR_NCPUS(mycpuid); 259 260 /* 261 * gre may cause infinite recursion calls when misconfigured. 262 * We'll prevent this by introducing upper limit. 263 */ 264 if (++(sc->called) > max_gre_nesting) { 265 kprintf("%s: gre_output: recursively called too many " 266 "times(%d)\n", if_name(&sc->sc_if), sc->called); 267 m_freem(m); 268 error = EIO; /* is there better errno? */ 269 goto end; 270 } 271 272 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 273 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 274 m_freem(m); 275 error = ENETDOWN; 276 goto end; 277 } 278 279 ro = &sc->route_pcpu[mycpuid]; 280 ro_dst = (struct sockaddr_in *)&ro->ro_dst; 281 if (ro->ro_rt != NULL && 282 ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 283 ro_dst->sin_addr.s_addr != sc->g_dst.s_addr)) { 284 RTFREE(ro->ro_rt); 285 ro->ro_rt = NULL; 286 } 287 if (ro->ro_rt == NULL) { 288 error = gre_compute_route(sc, ro); 289 if (error) { 290 m_freem(m); 291 goto end; 292 } 293 } 294 295 gh = NULL; 296 ip = NULL; 297 298 if (ifp->if_bpf) { 299 bpf_gettoken(); 300 if (ifp->if_bpf) { 301 uint32_t af = dst->sa_family; 302 303 bpf_ptap(ifp->if_bpf, m, &af, sizeof(af)); 304 } 305 bpf_reltoken(); 306 } 307 308 m->m_flags &= ~(M_BCAST|M_MCAST); 309 310 if (sc->g_proto == IPPROTO_MOBILE) { 311 if (dst->sa_family == AF_INET) { 312 struct mbuf *m0; 313 int msiz; 314 315 ip = mtod(m, struct ip *); 316 317 /* 318 * RFC2004 specifies that fragmented datagrams shouldn't 319 * be encapsulated. 320 */ 321 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) { 322 m_freem(m); 323 error = EINVAL; /* is there better errno? */ 324 goto end; 325 } 326 memset(&mob_h, 0, MOB_H_SIZ_L); 327 mob_h.proto = (ip->ip_p) << 8; 328 mob_h.odst = ip->ip_dst.s_addr; 329 ip->ip_dst.s_addr = sc->g_dst.s_addr; 330 331 /* 332 * If the packet comes from our host, we only change 333 * the destination address in the IP header. 334 * Else we also need to save and change the source 335 */ 336 if (in_hosteq(ip->ip_src, sc->g_src)) { 337 msiz = MOB_H_SIZ_S; 338 } else { 339 mob_h.proto |= MOB_H_SBIT; 340 mob_h.osrc = ip->ip_src.s_addr; 341 ip->ip_src.s_addr = sc->g_src.s_addr; 342 msiz = MOB_H_SIZ_L; 343 } 344 mob_h.proto = htons(mob_h.proto); 345 mob_h.hcrc = gre_in_cksum((u_short *)&mob_h, msiz); 346 347 if ((m->m_data - msiz) < m->m_pktdat) { 348 /* need new mbuf */ 349 MGETHDR(m0, M_NOWAIT, MT_HEADER); 350 if (m0 == NULL) { 351 m_freem(m); 352 error = ENOBUFS; 353 goto end; 354 } 355 m0->m_next = m; 356 m->m_data += sizeof(struct ip); 357 m->m_len -= sizeof(struct ip); 358 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 359 m0->m_len = msiz + sizeof(struct ip); 360 m0->m_data += max_linkhdr; 361 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 362 sizeof(struct ip)); 363 m = m0; 364 } else { /* we have some space left in the old one */ 365 m->m_data -= msiz; 366 m->m_len += msiz; 367 m->m_pkthdr.len += msiz; 368 bcopy(ip, mtod(m, caddr_t), 369 sizeof(struct ip)); 370 } 371 ip = mtod(m, struct ip *); 372 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 373 ip->ip_len = htons(ntohs(ip->ip_len) + msiz); 374 } else { /* AF_INET */ 375 m_freem(m); 376 error = EINVAL; 377 goto end; 378 } 379 } else if (sc->g_proto == IPPROTO_GRE) { 380 switch (dst->sa_family) { 381 case AF_INET: 382 ip = mtod(m, struct ip *); 383 etype = ETHERTYPE_IP; 384 break; 385 default: 386 m_freem(m); 387 error = EAFNOSUPPORT; 388 goto end; 389 } 390 M_PREPEND(m, sizeof(struct greip), M_NOWAIT); 391 } else { 392 m_freem(m); 393 error = EINVAL; 394 goto end; 395 } 396 397 if (m == NULL) { /* impossible */ 398 error = ENOBUFS; 399 goto end; 400 } 401 402 gh = mtod(m, struct greip *); 403 if (sc->g_proto == IPPROTO_GRE) { 404 /* we don't have any GRE flags for now */ 405 406 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 407 gh->gi_ptype = htons(etype); 408 } 409 410 gh->gi_pr = sc->g_proto; 411 if (sc->g_proto != IPPROTO_MOBILE) { 412 gh->gi_src = sc->g_src; 413 gh->gi_dst = sc->g_dst; 414 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 415 ((struct ip*)gh)->ip_ttl = GRE_TTL; 416 ((struct ip*)gh)->ip_tos = ip->ip_tos; 417 ((struct ip*)gh)->ip_id = ip->ip_id; 418 gh->gi_len = htons(m->m_pkthdr.len); 419 } 420 421 IFNET_STAT_INC(ifp, opackets, 1); 422 IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len); 423 /* send it off */ 424 error = ip_output(m, NULL, ro, IP_DEBUGROUTE, NULL, NULL); 425 end: 426 sc->called = 0; 427 if (error) 428 IFNET_STAT_INC(ifp, oerrors, 1); 429 return (error); 430 } 431 432 static int 433 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 434 struct rtentry *rt) 435 { 436 struct ifaltq_subque *ifsq = ifq_get_subq_default(&ifp->if_snd); 437 int error; 438 439 ifsq_serialize_hw(ifsq); 440 error = gre_output_serialized(ifp, m, dst, rt); 441 ifsq_deserialize_hw(ifsq); 442 443 return error; 444 } 445 446 static int 447 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr) 448 { 449 struct ifreq *ifr = (struct ifreq *)data; 450 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 451 struct in_aliasreq *aifr = (struct in_aliasreq *)data; 452 struct gre_softc *sc = ifp->if_softc; 453 struct sockaddr_in si; 454 struct sockaddr *sa = NULL; 455 int error; 456 struct sockaddr_in sp, sm, dp, dm; 457 458 error = 0; 459 460 crit_enter(); 461 switch (cmd) { 462 case SIOCSIFADDR: 463 ifp->if_flags |= IFF_UP; 464 break; 465 case SIOCSIFDSTADDR: 466 break; 467 case SIOCSIFFLAGS: 468 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 469 break; 470 if ((ifr->ifr_flags & IFF_LINK0) != 0) 471 sc->g_proto = IPPROTO_GRE; 472 else 473 sc->g_proto = IPPROTO_MOBILE; 474 goto recompute; 475 case SIOCSIFMTU: 476 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 477 break; 478 if (ifr->ifr_mtu < 576) { 479 error = EINVAL; 480 break; 481 } 482 ifp->if_mtu = ifr->ifr_mtu; 483 break; 484 case SIOCGIFMTU: 485 ifr->ifr_mtu = sc->sc_if.if_mtu; 486 break; 487 case SIOCADDMULTI: 488 case SIOCDELMULTI: 489 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 490 break; 491 if (ifr == NULL) { 492 error = EAFNOSUPPORT; 493 break; 494 } 495 switch (ifr->ifr_addr.sa_family) { 496 #ifdef INET 497 case AF_INET: 498 break; 499 #endif 500 default: 501 error = EAFNOSUPPORT; 502 break; 503 } 504 break; 505 case GRESPROTO: 506 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 507 break; 508 sc->g_proto = ifr->ifr_flags; 509 switch (sc->g_proto) { 510 case IPPROTO_GRE: 511 ifp->if_flags |= IFF_LINK0; 512 break; 513 case IPPROTO_MOBILE: 514 ifp->if_flags &= ~IFF_LINK0; 515 break; 516 default: 517 error = EPROTONOSUPPORT; 518 break; 519 } 520 goto recompute; 521 case GREGPROTO: 522 ifr->ifr_flags = sc->g_proto; 523 break; 524 case GRESADDRS: 525 case GRESADDRD: 526 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 527 break; 528 /* 529 * set tunnel endpoints, compute a less specific route 530 * to the remote end and mark if as up 531 */ 532 sa = &ifr->ifr_addr; 533 if (cmd == GRESADDRS) 534 sc->g_src = (satosin(sa))->sin_addr; 535 if (cmd == GRESADDRD) 536 sc->g_dst = (satosin(sa))->sin_addr; 537 recompute: 538 #ifdef INET 539 if (sc->encap != NULL) { 540 encap_detach(sc->encap); 541 sc->encap = NULL; 542 } 543 #endif 544 if ((sc->g_src.s_addr != INADDR_ANY) && 545 (sc->g_dst.s_addr != INADDR_ANY)) { 546 bzero(&sp, sizeof(sp)); 547 bzero(&sm, sizeof(sm)); 548 bzero(&dp, sizeof(dp)); 549 bzero(&dm, sizeof(dm)); 550 sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len = 551 sizeof(struct sockaddr_in); 552 sp.sin_family = sm.sin_family = dp.sin_family = 553 dm.sin_family = AF_INET; 554 sp.sin_addr = sc->g_src; 555 dp.sin_addr = sc->g_dst; 556 sm.sin_addr.s_addr = dm.sin_addr.s_addr = 557 INADDR_BROADCAST; 558 #ifdef INET 559 sc->encap = encap_attach(AF_INET, sc->g_proto, 560 sintosa(&sp), sintosa(&sm), sintosa(&dp), 561 sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ? 562 &in_gre_protosw : &in_mobile_protosw, sc); 563 if (sc->encap == NULL) 564 kprintf("%s: unable to attach encap\n", 565 if_name(&sc->sc_if)); 566 #endif 567 ifnet_deserialize_all(ifp); 568 error = gre_check_route(sc); 569 ifnet_serialize_all(ifp); 570 if (!error) 571 ifp->if_flags |= IFF_RUNNING; 572 else 573 ifp->if_flags &= ~IFF_RUNNING; 574 } 575 break; 576 case GREGADDRS: 577 memset(&si, 0, sizeof(si)); 578 si.sin_family = AF_INET; 579 si.sin_len = sizeof(struct sockaddr_in); 580 si.sin_addr.s_addr = sc->g_src.s_addr; 581 sa = sintosa(&si); 582 ifr->ifr_addr = *sa; 583 break; 584 case GREGADDRD: 585 memset(&si, 0, sizeof(si)); 586 si.sin_family = AF_INET; 587 si.sin_len = sizeof(struct sockaddr_in); 588 si.sin_addr.s_addr = sc->g_dst.s_addr; 589 sa = sintosa(&si); 590 ifr->ifr_addr = *sa; 591 break; 592 case SIOCSIFPHYADDR: 593 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 594 break; 595 if (aifr->ifra_addr.sin_family != AF_INET || 596 aifr->ifra_dstaddr.sin_family != AF_INET) { 597 error = EAFNOSUPPORT; 598 break; 599 } 600 if (aifr->ifra_addr.sin_len != sizeof(si) || 601 aifr->ifra_dstaddr.sin_len != sizeof(si)) { 602 error = EINVAL; 603 break; 604 } 605 sc->g_src = aifr->ifra_addr.sin_addr; 606 sc->g_dst = aifr->ifra_dstaddr.sin_addr; 607 goto recompute; 608 case SIOCSLIFPHYADDR: 609 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 610 break; 611 if (lifr->addr.ss_family != AF_INET || 612 lifr->dstaddr.ss_family != AF_INET) { 613 error = EAFNOSUPPORT; 614 break; 615 } 616 if (lifr->addr.ss_len != sizeof(si) || 617 lifr->dstaddr.ss_len != sizeof(si)) { 618 error = EINVAL; 619 break; 620 } 621 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 622 sc->g_dst = 623 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 624 goto recompute; 625 case SIOCDIFPHYADDR: 626 if ((error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY)) != 0) 627 break; 628 sc->g_src.s_addr = INADDR_ANY; 629 sc->g_dst.s_addr = INADDR_ANY; 630 goto recompute; 631 case SIOCGLIFPHYADDR: 632 if (sc->g_src.s_addr == INADDR_ANY || 633 sc->g_dst.s_addr == INADDR_ANY) { 634 error = EADDRNOTAVAIL; 635 break; 636 } 637 memset(&si, 0, sizeof(si)); 638 si.sin_family = AF_INET; 639 si.sin_len = sizeof(struct sockaddr_in); 640 si.sin_addr.s_addr = sc->g_src.s_addr; 641 memcpy(&lifr->addr, &si, sizeof(si)); 642 si.sin_addr.s_addr = sc->g_dst.s_addr; 643 memcpy(&lifr->dstaddr, &si, sizeof(si)); 644 break; 645 case SIOCGIFPSRCADDR: 646 if (sc->g_src.s_addr == INADDR_ANY) { 647 error = EADDRNOTAVAIL; 648 break; 649 } 650 memset(&si, 0, sizeof(si)); 651 si.sin_family = AF_INET; 652 si.sin_len = sizeof(struct sockaddr_in); 653 si.sin_addr.s_addr = sc->g_src.s_addr; 654 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 655 break; 656 case SIOCGIFPDSTADDR: 657 if (sc->g_dst.s_addr == INADDR_ANY) { 658 error = EADDRNOTAVAIL; 659 break; 660 } 661 memset(&si, 0, sizeof(si)); 662 si.sin_family = AF_INET; 663 si.sin_len = sizeof(struct sockaddr_in); 664 si.sin_addr.s_addr = sc->g_dst.s_addr; 665 bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr)); 666 break; 667 default: 668 error = EINVAL; 669 break; 670 } 671 672 crit_exit(); 673 return (error); 674 } 675 676 /* 677 * computes a route to our destination that is not the one 678 * which would be taken by ip_output(), as this one will loop back to 679 * us. If the interface is p2p as a--->b, then a routing entry exists 680 * If we now send a packet to b (e.g. ping b), this will come down here 681 * gets src=a, dst=b tacked on and would from ip_ouput() sent back to 682 * if_gre. 683 * Goal here is to compute a route to b that is less specific than 684 * a-->b. We know that this one exists as in normal operation we have 685 * at least a default route which matches. 686 */ 687 static int 688 gre_compute_route(struct gre_softc *sc, struct route *ro) 689 { 690 #ifdef DIAGNOSTIC 691 char abuf[INET_ADDRSTRLEN]; 692 #endif 693 u_int32_t a, b, c; 694 695 ASSERT_NETISR_NCPUS(mycpuid); 696 KASSERT(ro == &sc->route_pcpu[mycpuid], ("route mismatch")); 697 KASSERT(ro->ro_rt == NULL, ("rtentry not freed")); 698 699 memset(ro, 0, sizeof(struct route)); 700 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 701 ro->ro_dst.sa_family = AF_INET; 702 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 703 704 /* 705 * toggle last bit, so our interface is not found, but a less 706 * specific route. I'd rather like to specify a shorter mask, 707 * but this is not possible. Should work though. XXX 708 * there is a simpler way ... 709 */ 710 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 711 a = ntohl(sc->g_dst.s_addr); 712 b = a & 0x01; 713 c = a & 0xfffffffe; 714 b = b ^ 0x01; 715 a = b | c; 716 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 717 = htonl(a); 718 } 719 720 #ifdef DIAGNOSTIC 721 kprintf("%s: searching a route to %s", if_name(&sc->sc_if), 722 kinet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr, abuf)); 723 #endif 724 725 rtalloc(ro); 726 727 /* 728 * check if this returned a route at all and this route is no 729 * recursion to ourself 730 */ 731 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 732 #ifdef DIAGNOSTIC 733 if (ro->ro_rt == NULL) 734 kprintf(" - no route found!\n"); 735 else 736 kprintf(" - route loops back to ourself!\n"); 737 #endif 738 return EADDRNOTAVAIL; 739 } 740 741 /* 742 * now change it back - else ip_output will just drop 743 * the route and search one to this interface ... 744 */ 745 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 746 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 747 748 #ifdef DIAGNOSTIC 749 kprintf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp), 750 kinet_ntoa( 751 ((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr, abuf)); 752 kprintf("\n"); 753 #endif 754 755 return 0; 756 } 757 758 static void 759 gre_check_route_handler(netmsg_t msg) 760 { 761 struct gre_softc *sc = msg->base.lmsg.u.ms_resultp; 762 struct route *ro; 763 int error; 764 765 ASSERT_NETISR0; 766 767 ro = &sc->route_pcpu[mycpuid]; 768 if (ro->ro_rt != NULL) { 769 RTFREE(ro->ro_rt); 770 ro->ro_rt = NULL; 771 } 772 error = gre_compute_route(sc, ro); 773 774 netisr_replymsg(&msg->base, error); 775 } 776 777 static int 778 gre_check_route(struct gre_softc *sc) 779 { 780 struct netmsg_base msg; 781 782 netmsg_init(&msg, NULL, &curthread->td_msgport, MSGF_PRIORITY, 783 gre_check_route_handler); 784 msg.lmsg.u.ms_resultp = sc; 785 786 return (netisr_domsg(&msg, 0)); 787 } 788 789 /* 790 * do a checksum of a buffer - much like in_cksum, which operates on 791 * mbufs. 792 */ 793 u_short 794 gre_in_cksum(u_short *p, u_int len) 795 { 796 u_int sum = 0; 797 int nwords = len >> 1; 798 799 while (nwords-- != 0) 800 sum += *p++; 801 802 if (len & 1) { 803 union { 804 u_short w; 805 u_char c[2]; 806 } u; 807 u.c[0] = *(u_char *)p; 808 u.c[1] = 0; 809 sum += u.w; 810 } 811 812 /* end-around-carry */ 813 sum = (sum >> 16) + (sum & 0xffff); 814 sum += (sum >> 16); 815 return (~sum); 816 } 817 818 static int 819 gremodevent(module_t mod, int type, void *data) 820 { 821 822 switch (type) { 823 case MOD_LOAD: 824 greattach(); 825 break; 826 case MOD_UNLOAD: 827 if_clone_detach(&gre_cloner); 828 829 while (!LIST_EMPTY(&gre_softc_list)) 830 gre_clone_destroy(&LIST_FIRST(&gre_softc_list)->sc_if); 831 832 break; 833 } 834 return 0; 835 } 836 837 static moduledata_t gre_mod = { 838 "if_gre", 839 gremodevent, 840 0 841 }; 842 843 DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 844 MODULE_VERSION(if_gre, 1); 845