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 MPASS(in_epoch(net_epoch_preempt)); 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 MPASS(in_epoch(net_epoch_preempt)); 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 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 epoch_call(net_epoch_preempt, &gs->epoch_ctx, 288 gre_sofree); 289 } 290 gs = sc->gre_so = NULL; 291 } 292 } 293 294 if (gs == NULL) { 295 /* 296 * Check that socket for given address is already 297 * configured. 298 */ 299 gs = in_gre_lookup_socket(addr); 300 if (gs == NULL) { 301 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO); 302 s->addr = addr; 303 gs = &s->base; 304 305 error = socreate(sc->gre_family, &gs->so, 306 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred, 307 curthread); 308 if (error != 0) { 309 if_printf(GRE2IFP(sc), 310 "cannot create socket: %d\n", error); 311 free(s, M_GRE); 312 return (error); 313 } 314 315 error = udp_set_kernel_tunneling(gs->so, 316 in_gre_udp_input, NULL, gs); 317 if (error != 0) { 318 if_printf(GRE2IFP(sc), 319 "cannot set UDP tunneling: %d\n", error); 320 goto fail; 321 } 322 323 memset(&sopt, 0, sizeof(sopt)); 324 sopt.sopt_dir = SOPT_SET; 325 sopt.sopt_level = IPPROTO_IP; 326 sopt.sopt_name = IP_BINDANY; 327 sopt.sopt_val = &value; 328 sopt.sopt_valsize = sizeof(value); 329 value = 1; 330 error = sosetopt(gs->so, &sopt); 331 if (error != 0) { 332 if_printf(GRE2IFP(sc), 333 "cannot set IP_BINDANY opt: %d\n", error); 334 goto fail; 335 } 336 337 memset(&sin, 0, sizeof(sin)); 338 sin.sin_family = AF_INET; 339 sin.sin_len = sizeof(sin); 340 sin.sin_addr.s_addr = addr; 341 sin.sin_port = htons(GRE_UDPPORT); 342 error = sobind(gs->so, (struct sockaddr *)&sin, 343 curthread); 344 if (error != 0) { 345 if_printf(GRE2IFP(sc), 346 "cannot bind socket: %d\n", error); 347 goto fail; 348 } 349 /* Add socket to the chain */ 350 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain); 351 } 352 } 353 354 /* Add softc to the socket's list */ 355 CK_LIST_INSERT_HEAD(&gs->list, sc, chain); 356 sc->gre_so = gs; 357 return (0); 358 fail: 359 soclose(gs->so); 360 free(s, M_GRE); 361 return (error); 362 } 363 364 static int 365 in_gre_attach(struct gre_softc *sc) 366 { 367 struct grehdr *gh; 368 int error; 369 370 if (sc->gre_options & GRE_UDPENCAP) { 371 sc->gre_csumflags = CSUM_UDP; 372 sc->gre_hlen = sizeof(struct greudp); 373 sc->gre_oip.ip_p = IPPROTO_UDP; 374 gh = &sc->gre_udphdr->gi_gre; 375 gre_update_udphdr(sc, &sc->gre_udp, 376 in_pseudo(sc->gre_oip.ip_src.s_addr, 377 sc->gre_oip.ip_dst.s_addr, 0)); 378 } else { 379 sc->gre_hlen = sizeof(struct greip); 380 sc->gre_oip.ip_p = IPPROTO_GRE; 381 gh = &sc->gre_iphdr->gi_gre; 382 } 383 sc->gre_oip.ip_v = IPVERSION; 384 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2; 385 gre_update_hdr(sc, gh); 386 387 /* 388 * If we return error, this means that sc is not linked, 389 * and caller should reset gre_family and free(sc->gre_hdr). 390 */ 391 if (sc->gre_options & GRE_UDPENCAP) { 392 error = in_gre_setup_socket(sc); 393 if (error != 0) 394 return (error); 395 } else 396 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain); 397 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr), 398 sc, srchash); 399 400 /* Set IFF_DRV_RUNNING if interface is ready */ 401 in_gre_set_running(sc); 402 return (0); 403 } 404 405 int 406 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value) 407 { 408 int error; 409 410 /* NOTE: we are protected with gre_ioctl_sx lock */ 411 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT); 412 MPASS(sc->gre_family == AF_INET); 413 414 /* 415 * If we are going to change encapsulation protocol, do check 416 * for duplicate tunnels. Return EEXIST here to do not confuse 417 * user. 418 */ 419 if (cmd == GRESOPTS && 420 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) && 421 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr, 422 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL) 423 return (EEXIST); 424 425 CK_LIST_REMOVE(sc, chain); 426 CK_LIST_REMOVE(sc, srchash); 427 GRE_WAIT(); 428 switch (cmd) { 429 case GRESKEY: 430 sc->gre_key = value; 431 break; 432 case GRESOPTS: 433 sc->gre_options = value; 434 break; 435 case GRESPORT: 436 sc->gre_port = value; 437 break; 438 } 439 error = in_gre_attach(sc); 440 if (error != 0) { 441 sc->gre_family = 0; 442 free(sc->gre_hdr, M_GRE); 443 } 444 return (error); 445 } 446 447 int 448 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data) 449 { 450 struct ifreq *ifr = (struct ifreq *)data; 451 struct sockaddr_in *dst, *src; 452 struct ip *ip; 453 int error; 454 455 /* NOTE: we are protected with gre_ioctl_sx lock */ 456 error = EINVAL; 457 switch (cmd) { 458 case SIOCSIFPHYADDR: 459 src = &((struct in_aliasreq *)data)->ifra_addr; 460 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 461 462 /* sanity checks */ 463 if (src->sin_family != dst->sin_family || 464 src->sin_family != AF_INET || 465 src->sin_len != dst->sin_len || 466 src->sin_len != sizeof(*src)) 467 break; 468 if (src->sin_addr.s_addr == INADDR_ANY || 469 dst->sin_addr.s_addr == INADDR_ANY) { 470 error = EADDRNOTAVAIL; 471 break; 472 } 473 if (V_ipv4_hashtbl == NULL) { 474 V_ipv4_hashtbl = gre_hashinit(); 475 V_ipv4_srchashtbl = gre_hashinit(); 476 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit(); 477 } 478 error = in_gre_checkdup(sc, src->sin_addr.s_addr, 479 dst->sin_addr.s_addr, sc->gre_options); 480 if (error == EADDRNOTAVAIL) 481 break; 482 if (error == EEXIST) { 483 /* Addresses are the same. Just return. */ 484 error = 0; 485 break; 486 } 487 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t), 488 M_GRE, M_WAITOK | M_ZERO); 489 ip->ip_src.s_addr = src->sin_addr.s_addr; 490 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 491 if (sc->gre_family != 0) { 492 /* Detach existing tunnel first */ 493 CK_LIST_REMOVE(sc, chain); 494 CK_LIST_REMOVE(sc, srchash); 495 GRE_WAIT(); 496 free(sc->gre_hdr, M_GRE); 497 /* XXX: should we notify about link state change? */ 498 } 499 sc->gre_family = AF_INET; 500 sc->gre_hdr = ip; 501 sc->gre_oseq = 0; 502 sc->gre_iseq = UINT32_MAX; 503 error = in_gre_attach(sc); 504 if (error != 0) { 505 sc->gre_family = 0; 506 free(sc->gre_hdr, M_GRE); 507 } 508 break; 509 case SIOCGIFPSRCADDR: 510 case SIOCGIFPDSTADDR: 511 if (sc->gre_family != AF_INET) { 512 error = EADDRNOTAVAIL; 513 break; 514 } 515 src = (struct sockaddr_in *)&ifr->ifr_addr; 516 memset(src, 0, sizeof(*src)); 517 src->sin_family = AF_INET; 518 src->sin_len = sizeof(*src); 519 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 520 sc->gre_oip.ip_src: sc->gre_oip.ip_dst; 521 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 522 if (error != 0) 523 memset(src, 0, sizeof(*src)); 524 break; 525 } 526 return (error); 527 } 528 529 int 530 in_gre_output(struct mbuf *m, int af, int hlen) 531 { 532 struct greip *gi; 533 534 gi = mtod(m, struct greip *); 535 switch (af) { 536 case AF_INET: 537 /* 538 * gre_transmit() has used M_PREPEND() that doesn't guarantee 539 * m_data is contiguous more than hlen bytes. Use m_copydata() 540 * here to avoid m_pullup(). 541 */ 542 m_copydata(m, hlen + offsetof(struct ip, ip_tos), 543 sizeof(u_char), &gi->gi_ip.ip_tos); 544 m_copydata(m, hlen + offsetof(struct ip, ip_id), 545 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id); 546 break; 547 #ifdef INET6 548 case AF_INET6: 549 gi->gi_ip.ip_tos = 0; /* XXX */ 550 ip_fillid(&gi->gi_ip); 551 break; 552 #endif 553 } 554 gi->gi_ip.ip_ttl = V_ip_gre_ttl; 555 gi->gi_ip.ip_len = htons(m->m_pkthdr.len); 556 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL)); 557 } 558 559 static const struct srcaddrtab *ipv4_srcaddrtab = NULL; 560 static const struct encaptab *ecookie = NULL; 561 static const struct encap_config ipv4_encap_cfg = { 562 .proto = IPPROTO_GRE, 563 .min_length = sizeof(struct greip) + sizeof(struct ip), 564 .exact_match = ENCAP_DRV_LOOKUP, 565 .lookup = in_gre_lookup, 566 .input = gre_input 567 }; 568 569 void 570 in_gre_init(void) 571 { 572 573 if (!IS_DEFAULT_VNET(curvnet)) 574 return; 575 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr, 576 NULL, M_WAITOK); 577 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK); 578 } 579 580 void 581 in_gre_uninit(void) 582 { 583 584 if (IS_DEFAULT_VNET(curvnet)) { 585 ip_encap_detach(ecookie); 586 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 587 } 588 if (V_ipv4_hashtbl != NULL) { 589 gre_hashdestroy(V_ipv4_hashtbl); 590 V_ipv4_hashtbl = NULL; 591 GRE_WAIT(); 592 gre_hashdestroy(V_ipv4_srchashtbl); 593 gre_hashdestroy((struct gre_list *)V_ipv4_sockets); 594 } 595 } 596