1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-NetBSD 3 * 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * Copyright (c) 2014, 2018 Andrey V. Elsukov <ae@FreeBSD.org> 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 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de> 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 * POSSIBILITY OF SUCH DAMAGE. 33 * 34 * $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $ 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_inet.h" 41 #include "opt_inet6.h" 42 43 #include <sys/param.h> 44 #include <sys/jail.h> 45 #include <sys/systm.h> 46 #include <sys/socket.h> 47 #include <sys/socketvar.h> 48 #include <sys/sockio.h> 49 #include <sys/mbuf.h> 50 #include <sys/errno.h> 51 #include <sys/kernel.h> 52 #include <sys/sysctl.h> 53 #include <sys/malloc.h> 54 #include <sys/proc.h> 55 56 #include <net/if.h> 57 #include <net/if_var.h> 58 #include <net/vnet.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_var.h> 62 #include <netinet/in_pcb.h> 63 #include <netinet/ip.h> 64 #include <netinet/ip_encap.h> 65 #include <netinet/ip_var.h> 66 #include <netinet/udp.h> 67 #include <netinet/udp_var.h> 68 69 #ifdef INET6 70 #include <netinet/ip6.h> 71 #endif 72 73 #include <net/if_gre.h> 74 #include <machine/in_cksum.h> 75 76 #define GRE_TTL 30 77 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL; 78 #define V_ip_gre_ttl VNET(ip_gre_ttl) 79 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW, 80 &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets"); 81 82 struct in_gre_socket { 83 struct gre_socket base; 84 in_addr_t addr; 85 }; 86 VNET_DEFINE_STATIC(struct gre_sockets *, ipv4_sockets) = NULL; 87 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL; 88 VNET_DEFINE_STATIC(struct gre_list *, ipv4_srchashtbl) = NULL; 89 #define V_ipv4_sockets VNET(ipv4_sockets) 90 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 91 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 92 #define GRE_HASH(src, dst) (V_ipv4_hashtbl[\ 93 in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)]) 94 #define GRE_SRCHASH(src) (V_ipv4_srchashtbl[\ 95 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)]) 96 #define GRE_SOCKHASH(src) (V_ipv4_sockets[\ 97 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)]) 98 #define GRE_HASH_SC(sc) GRE_HASH((sc)->gre_oip.ip_src.s_addr,\ 99 (sc)->gre_oip.ip_dst.s_addr) 100 101 static uint32_t 102 in_gre_hashval(in_addr_t src, in_addr_t dst) 103 { 104 uint32_t ret; 105 106 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 107 return (fnv_32_buf(&dst, sizeof(dst), ret)); 108 } 109 110 static struct gre_socket* 111 in_gre_lookup_socket(in_addr_t addr) 112 { 113 struct gre_socket *gs; 114 struct in_gre_socket *s; 115 116 CK_LIST_FOREACH(gs, &GRE_SOCKHASH(addr), chain) { 117 s = __containerof(gs, struct in_gre_socket, base); 118 if (s->addr == addr) 119 break; 120 } 121 return (gs); 122 } 123 124 static int 125 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst, 126 uint32_t opts) 127 { 128 struct gre_list *head; 129 struct gre_softc *tmp; 130 struct gre_socket *gs; 131 132 if (sc->gre_family == AF_INET && 133 sc->gre_oip.ip_src.s_addr == src && 134 sc->gre_oip.ip_dst.s_addr == dst && 135 (sc->gre_options & GRE_UDPENCAP) == (opts & GRE_UDPENCAP)) 136 return (EEXIST); 137 138 if (opts & GRE_UDPENCAP) { 139 gs = in_gre_lookup_socket(src); 140 if (gs == NULL) 141 return (0); 142 head = &gs->list; 143 } else 144 head = &GRE_HASH(src, dst); 145 146 CK_LIST_FOREACH(tmp, head, chain) { 147 if (tmp == sc) 148 continue; 149 if (tmp->gre_oip.ip_src.s_addr == src && 150 tmp->gre_oip.ip_dst.s_addr == dst) 151 return (EADDRNOTAVAIL); 152 } 153 return (0); 154 } 155 156 static int 157 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg) 158 { 159 const struct ip *ip; 160 struct gre_softc *sc; 161 162 if (V_ipv4_hashtbl == NULL) 163 return (0); 164 165 NET_EPOCH_ASSERT(); 166 ip = mtod(m, const struct ip *); 167 CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr, 168 ip->ip_src.s_addr), chain) { 169 /* 170 * This is an inbound packet, its ip_dst is source address 171 * in softc. 172 */ 173 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr && 174 sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) { 175 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0) 176 return (0); 177 *arg = sc; 178 return (ENCAP_DRV_LOOKUP); 179 } 180 } 181 return (0); 182 } 183 184 /* 185 * Check that ingress address belongs to local host. 186 */ 187 static void 188 in_gre_set_running(struct gre_softc *sc) 189 { 190 191 if (in_localip(sc->gre_oip.ip_src)) 192 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 193 else 194 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 195 } 196 197 /* 198 * ifaddr_event handler. 199 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 200 * source address spoofing. 201 */ 202 static void 203 in_gre_srcaddr(void *arg __unused, const struct sockaddr *sa, 204 int event __unused) 205 { 206 const struct sockaddr_in *sin; 207 struct gre_softc *sc; 208 209 /* Check that VNET is ready */ 210 if (V_ipv4_hashtbl == NULL) 211 return; 212 213 NET_EPOCH_ASSERT(); 214 sin = (const struct sockaddr_in *)sa; 215 CK_LIST_FOREACH(sc, &GRE_SRCHASH(sin->sin_addr.s_addr), srchash) { 216 if (sc->gre_oip.ip_src.s_addr != sin->sin_addr.s_addr) 217 continue; 218 in_gre_set_running(sc); 219 } 220 } 221 222 static void 223 in_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp, 224 const struct sockaddr *sa, void *ctx) 225 { 226 struct epoch_tracker et; 227 struct gre_socket *gs; 228 struct gre_softc *sc; 229 in_addr_t dst; 230 231 NET_EPOCH_ENTER(et); 232 /* 233 * udp_append() holds reference to inp, it is safe to check 234 * inp_flags2 without INP_RLOCK(). 235 * If socket was closed before we have entered NET_EPOCH section, 236 * INP_FREED flag should be set. Otherwise it should be safe to 237 * make access to ctx data, because gre_so will be freed by 238 * gre_sofree() via NET_EPOCH_CALL(). 239 */ 240 if (__predict_false(inp->inp_flags2 & INP_FREED)) { 241 NET_EPOCH_EXIT(et); 242 m_freem(m); 243 return; 244 } 245 246 gs = (struct gre_socket *)ctx; 247 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr; 248 CK_LIST_FOREACH(sc, &gs->list, chain) { 249 if (sc->gre_oip.ip_dst.s_addr == dst) 250 break; 251 } 252 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){ 253 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc); 254 NET_EPOCH_EXIT(et); 255 return; 256 } 257 m_freem(m); 258 NET_EPOCH_EXIT(et); 259 } 260 261 static int 262 in_gre_setup_socket(struct gre_softc *sc) 263 { 264 struct sockopt sopt; 265 struct sockaddr_in sin; 266 struct in_gre_socket *s; 267 struct gre_socket *gs; 268 in_addr_t addr; 269 int error, value; 270 271 /* 272 * NOTE: we are protected with gre_ioctl_sx lock. 273 * 274 * First check that socket is already configured. 275 * If so, check that source addres was not changed. 276 * If address is different, check that there are no other tunnels 277 * and close socket. 278 */ 279 addr = sc->gre_oip.ip_src.s_addr; 280 gs = sc->gre_so; 281 if (gs != NULL) { 282 s = __containerof(gs, struct in_gre_socket, base); 283 if (s->addr != addr) { 284 if (CK_LIST_EMPTY(&gs->list)) { 285 CK_LIST_REMOVE(gs, chain); 286 soclose(gs->so); 287 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx); 288 } 289 gs = sc->gre_so = NULL; 290 } 291 } 292 293 if (gs == NULL) { 294 /* 295 * Check that socket for given address is already 296 * configured. 297 */ 298 gs = in_gre_lookup_socket(addr); 299 if (gs == NULL) { 300 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO); 301 s->addr = addr; 302 gs = &s->base; 303 304 error = socreate(sc->gre_family, &gs->so, 305 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred, 306 curthread); 307 if (error != 0) { 308 if_printf(GRE2IFP(sc), 309 "cannot create socket: %d\n", error); 310 free(s, M_GRE); 311 return (error); 312 } 313 314 error = udp_set_kernel_tunneling(gs->so, 315 in_gre_udp_input, NULL, gs); 316 if (error != 0) { 317 if_printf(GRE2IFP(sc), 318 "cannot set UDP tunneling: %d\n", error); 319 goto fail; 320 } 321 322 memset(&sopt, 0, sizeof(sopt)); 323 sopt.sopt_dir = SOPT_SET; 324 sopt.sopt_level = IPPROTO_IP; 325 sopt.sopt_name = IP_BINDANY; 326 sopt.sopt_val = &value; 327 sopt.sopt_valsize = sizeof(value); 328 value = 1; 329 error = sosetopt(gs->so, &sopt); 330 if (error != 0) { 331 if_printf(GRE2IFP(sc), 332 "cannot set IP_BINDANY opt: %d\n", error); 333 goto fail; 334 } 335 336 memset(&sin, 0, sizeof(sin)); 337 sin.sin_family = AF_INET; 338 sin.sin_len = sizeof(sin); 339 sin.sin_addr.s_addr = addr; 340 sin.sin_port = htons(GRE_UDPPORT); 341 error = sobind(gs->so, (struct sockaddr *)&sin, 342 curthread); 343 if (error != 0) { 344 if_printf(GRE2IFP(sc), 345 "cannot bind socket: %d\n", error); 346 goto fail; 347 } 348 /* Add socket to the chain */ 349 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain); 350 } 351 } 352 353 /* Add softc to the socket's list */ 354 CK_LIST_INSERT_HEAD(&gs->list, sc, chain); 355 sc->gre_so = gs; 356 return (0); 357 fail: 358 soclose(gs->so); 359 free(s, M_GRE); 360 return (error); 361 } 362 363 static int 364 in_gre_attach(struct gre_softc *sc) 365 { 366 struct grehdr *gh; 367 int error; 368 369 if (sc->gre_options & GRE_UDPENCAP) { 370 sc->gre_csumflags = CSUM_UDP; 371 sc->gre_hlen = sizeof(struct greudp); 372 sc->gre_oip.ip_p = IPPROTO_UDP; 373 gh = &sc->gre_udphdr->gi_gre; 374 gre_update_udphdr(sc, &sc->gre_udp, 375 in_pseudo(sc->gre_oip.ip_src.s_addr, 376 sc->gre_oip.ip_dst.s_addr, 0)); 377 } else { 378 sc->gre_hlen = sizeof(struct greip); 379 sc->gre_oip.ip_p = IPPROTO_GRE; 380 gh = &sc->gre_iphdr->gi_gre; 381 } 382 sc->gre_oip.ip_v = IPVERSION; 383 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2; 384 gre_update_hdr(sc, gh); 385 386 /* 387 * If we return error, this means that sc is not linked, 388 * and caller should reset gre_family and free(sc->gre_hdr). 389 */ 390 if (sc->gre_options & GRE_UDPENCAP) { 391 error = in_gre_setup_socket(sc); 392 if (error != 0) 393 return (error); 394 } else 395 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain); 396 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr), 397 sc, srchash); 398 399 /* Set IFF_DRV_RUNNING if interface is ready */ 400 in_gre_set_running(sc); 401 return (0); 402 } 403 404 int 405 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value) 406 { 407 int error; 408 409 /* NOTE: we are protected with gre_ioctl_sx lock */ 410 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT); 411 MPASS(sc->gre_family == AF_INET); 412 413 /* 414 * If we are going to change encapsulation protocol, do check 415 * for duplicate tunnels. Return EEXIST here to do not confuse 416 * user. 417 */ 418 if (cmd == GRESOPTS && 419 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) && 420 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr, 421 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL) 422 return (EEXIST); 423 424 CK_LIST_REMOVE(sc, chain); 425 CK_LIST_REMOVE(sc, srchash); 426 GRE_WAIT(); 427 switch (cmd) { 428 case GRESKEY: 429 sc->gre_key = value; 430 break; 431 case GRESOPTS: 432 sc->gre_options = value; 433 break; 434 case GRESPORT: 435 sc->gre_port = value; 436 break; 437 } 438 error = in_gre_attach(sc); 439 if (error != 0) { 440 sc->gre_family = 0; 441 free(sc->gre_hdr, M_GRE); 442 } 443 return (error); 444 } 445 446 int 447 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data) 448 { 449 struct ifreq *ifr = (struct ifreq *)data; 450 struct sockaddr_in *dst, *src; 451 struct ip *ip; 452 int error; 453 454 /* NOTE: we are protected with gre_ioctl_sx lock */ 455 error = EINVAL; 456 switch (cmd) { 457 case SIOCSIFPHYADDR: 458 src = &((struct in_aliasreq *)data)->ifra_addr; 459 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 460 461 /* sanity checks */ 462 if (src->sin_family != dst->sin_family || 463 src->sin_family != AF_INET || 464 src->sin_len != dst->sin_len || 465 src->sin_len != sizeof(*src)) 466 break; 467 if (src->sin_addr.s_addr == INADDR_ANY || 468 dst->sin_addr.s_addr == INADDR_ANY) { 469 error = EADDRNOTAVAIL; 470 break; 471 } 472 if (V_ipv4_hashtbl == NULL) { 473 V_ipv4_hashtbl = gre_hashinit(); 474 V_ipv4_srchashtbl = gre_hashinit(); 475 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit(); 476 } 477 error = in_gre_checkdup(sc, src->sin_addr.s_addr, 478 dst->sin_addr.s_addr, sc->gre_options); 479 if (error == EADDRNOTAVAIL) 480 break; 481 if (error == EEXIST) { 482 /* Addresses are the same. Just return. */ 483 error = 0; 484 break; 485 } 486 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t), 487 M_GRE, M_WAITOK | M_ZERO); 488 ip->ip_src.s_addr = src->sin_addr.s_addr; 489 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 490 if (sc->gre_family != 0) { 491 /* Detach existing tunnel first */ 492 CK_LIST_REMOVE(sc, chain); 493 CK_LIST_REMOVE(sc, srchash); 494 GRE_WAIT(); 495 free(sc->gre_hdr, M_GRE); 496 /* XXX: should we notify about link state change? */ 497 } 498 sc->gre_family = AF_INET; 499 sc->gre_hdr = ip; 500 sc->gre_oseq = 0; 501 sc->gre_iseq = UINT32_MAX; 502 error = in_gre_attach(sc); 503 if (error != 0) { 504 sc->gre_family = 0; 505 free(sc->gre_hdr, M_GRE); 506 } 507 break; 508 case SIOCGIFPSRCADDR: 509 case SIOCGIFPDSTADDR: 510 if (sc->gre_family != AF_INET) { 511 error = EADDRNOTAVAIL; 512 break; 513 } 514 src = (struct sockaddr_in *)&ifr->ifr_addr; 515 memset(src, 0, sizeof(*src)); 516 src->sin_family = AF_INET; 517 src->sin_len = sizeof(*src); 518 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 519 sc->gre_oip.ip_src: sc->gre_oip.ip_dst; 520 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 521 if (error != 0) 522 memset(src, 0, sizeof(*src)); 523 break; 524 } 525 return (error); 526 } 527 528 int 529 in_gre_output(struct mbuf *m, int af, int hlen) 530 { 531 struct greip *gi; 532 533 gi = mtod(m, struct greip *); 534 switch (af) { 535 case AF_INET: 536 /* 537 * gre_transmit() has used M_PREPEND() that doesn't guarantee 538 * m_data is contiguous more than hlen bytes. Use m_copydata() 539 * here to avoid m_pullup(). 540 */ 541 m_copydata(m, hlen + offsetof(struct ip, ip_tos), 542 sizeof(u_char), &gi->gi_ip.ip_tos); 543 m_copydata(m, hlen + offsetof(struct ip, ip_id), 544 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id); 545 break; 546 #ifdef INET6 547 case AF_INET6: 548 gi->gi_ip.ip_tos = 0; /* XXX */ 549 ip_fillid(&gi->gi_ip); 550 break; 551 #endif 552 } 553 gi->gi_ip.ip_ttl = V_ip_gre_ttl; 554 gi->gi_ip.ip_len = htons(m->m_pkthdr.len); 555 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL)); 556 } 557 558 static const struct srcaddrtab *ipv4_srcaddrtab = NULL; 559 static const struct encaptab *ecookie = NULL; 560 static const struct encap_config ipv4_encap_cfg = { 561 .proto = IPPROTO_GRE, 562 .min_length = sizeof(struct greip) + sizeof(struct ip), 563 .exact_match = ENCAP_DRV_LOOKUP, 564 .lookup = in_gre_lookup, 565 .input = gre_input 566 }; 567 568 void 569 in_gre_init(void) 570 { 571 572 if (!IS_DEFAULT_VNET(curvnet)) 573 return; 574 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr, 575 NULL, M_WAITOK); 576 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK); 577 } 578 579 void 580 in_gre_uninit(void) 581 { 582 583 if (IS_DEFAULT_VNET(curvnet)) { 584 ip_encap_detach(ecookie); 585 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 586 } 587 if (V_ipv4_hashtbl != NULL) { 588 gre_hashdestroy(V_ipv4_hashtbl); 589 V_ipv4_hashtbl = NULL; 590 GRE_WAIT(); 591 gre_hashdestroy(V_ipv4_srchashtbl); 592 gre_hashdestroy((struct gre_list *)V_ipv4_sockets); 593 } 594 } 595