1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/if_private.h> 59 #include <net/vnet.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_var.h> 63 #include <netinet/in_pcb.h> 64 #include <netinet/ip.h> 65 #include <netinet/ip_encap.h> 66 #include <netinet/ip_var.h> 67 #include <netinet/udp.h> 68 #include <netinet/udp_var.h> 69 70 #ifdef INET6 71 #include <netinet/ip6.h> 72 #endif 73 74 #include <net/if_gre.h> 75 #include <machine/in_cksum.h> 76 77 #define GRE_TTL 30 78 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL; 79 #define V_ip_gre_ttl VNET(ip_gre_ttl) 80 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW, 81 &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets"); 82 83 struct in_gre_socket { 84 struct gre_socket base; 85 in_addr_t addr; 86 }; 87 VNET_DEFINE_STATIC(struct gre_sockets *, ipv4_sockets) = NULL; 88 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL; 89 VNET_DEFINE_STATIC(struct gre_list *, ipv4_srchashtbl) = NULL; 90 #define V_ipv4_sockets VNET(ipv4_sockets) 91 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 92 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 93 #define GRE_HASH(src, dst) (V_ipv4_hashtbl[\ 94 in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)]) 95 #define GRE_SRCHASH(src) (V_ipv4_srchashtbl[\ 96 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)]) 97 #define GRE_SOCKHASH(src) (V_ipv4_sockets[\ 98 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)]) 99 #define GRE_HASH_SC(sc) GRE_HASH((sc)->gre_oip.ip_src.s_addr,\ 100 (sc)->gre_oip.ip_dst.s_addr) 101 102 static uint32_t 103 in_gre_hashval(in_addr_t src, in_addr_t dst) 104 { 105 uint32_t ret; 106 107 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 108 return (fnv_32_buf(&dst, sizeof(dst), ret)); 109 } 110 111 static struct gre_socket* 112 in_gre_lookup_socket(in_addr_t addr) 113 { 114 struct gre_socket *gs; 115 struct in_gre_socket *s; 116 117 CK_LIST_FOREACH(gs, &GRE_SOCKHASH(addr), chain) { 118 s = __containerof(gs, struct in_gre_socket, base); 119 if (s->addr == addr) 120 break; 121 } 122 return (gs); 123 } 124 125 static int 126 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst, 127 uint32_t opts) 128 { 129 struct gre_list *head; 130 struct gre_softc *tmp; 131 struct gre_socket *gs; 132 133 if (sc->gre_family == AF_INET && 134 sc->gre_oip.ip_src.s_addr == src && 135 sc->gre_oip.ip_dst.s_addr == dst && 136 (sc->gre_options & GRE_UDPENCAP) == (opts & GRE_UDPENCAP)) 137 return (EEXIST); 138 139 if (opts & GRE_UDPENCAP) { 140 gs = in_gre_lookup_socket(src); 141 if (gs == NULL) 142 return (0); 143 head = &gs->list; 144 } else 145 head = &GRE_HASH(src, dst); 146 147 CK_LIST_FOREACH(tmp, head, chain) { 148 if (tmp == sc) 149 continue; 150 if (tmp->gre_oip.ip_src.s_addr == src && 151 tmp->gre_oip.ip_dst.s_addr == dst) 152 return (EADDRNOTAVAIL); 153 } 154 return (0); 155 } 156 157 static int 158 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg) 159 { 160 const struct ip *ip; 161 struct gre_softc *sc; 162 163 if (V_ipv4_hashtbl == NULL) 164 return (0); 165 166 NET_EPOCH_ASSERT(); 167 ip = mtod(m, const struct ip *); 168 CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr, 169 ip->ip_src.s_addr), chain) { 170 /* 171 * This is an inbound packet, its ip_dst is source address 172 * in softc. 173 */ 174 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr && 175 sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) { 176 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0) 177 return (0); 178 *arg = sc; 179 return (ENCAP_DRV_LOOKUP); 180 } 181 } 182 return (0); 183 } 184 185 /* 186 * Check that ingress address belongs to local host. 187 */ 188 static void 189 in_gre_set_running(struct gre_softc *sc) 190 { 191 192 if (in_localip(sc->gre_oip.ip_src)) 193 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 194 else 195 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 196 } 197 198 /* 199 * ifaddr_event handler. 200 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 201 * source address spoofing. 202 */ 203 static void 204 in_gre_srcaddr(void *arg __unused, const struct sockaddr *sa, 205 int event __unused) 206 { 207 const struct sockaddr_in *sin; 208 struct gre_softc *sc; 209 210 /* Check that VNET is ready */ 211 if (V_ipv4_hashtbl == NULL) 212 return; 213 214 NET_EPOCH_ASSERT(); 215 sin = (const struct sockaddr_in *)sa; 216 CK_LIST_FOREACH(sc, &GRE_SRCHASH(sin->sin_addr.s_addr), srchash) { 217 if (sc->gre_oip.ip_src.s_addr != sin->sin_addr.s_addr) 218 continue; 219 in_gre_set_running(sc); 220 } 221 } 222 223 static bool 224 in_gre_udp_input(struct mbuf *m, int off, struct inpcb *inp, 225 const struct sockaddr *sa, void *ctx) 226 { 227 struct gre_socket *gs; 228 struct gre_softc *sc; 229 in_addr_t dst; 230 231 NET_EPOCH_ASSERT(); 232 233 gs = (struct gre_socket *)ctx; 234 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr; 235 CK_LIST_FOREACH(sc, &gs->list, chain) { 236 if (sc->gre_oip.ip_dst.s_addr == dst) 237 break; 238 } 239 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){ 240 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc); 241 return (true); 242 } 243 m_freem(m); 244 245 return (true); 246 } 247 248 static int 249 in_gre_setup_socket(struct gre_softc *sc) 250 { 251 struct sockopt sopt; 252 struct sockaddr_in sin; 253 struct in_gre_socket *s; 254 struct gre_socket *gs; 255 in_addr_t addr; 256 int error, value; 257 258 /* 259 * NOTE: we are protected with gre_ioctl_sx lock. 260 * 261 * First check that socket is already configured. 262 * If so, check that source address was not changed. 263 * If address is different, check that there are no other tunnels 264 * and close socket. 265 */ 266 addr = sc->gre_oip.ip_src.s_addr; 267 gs = sc->gre_so; 268 if (gs != NULL) { 269 s = __containerof(gs, struct in_gre_socket, base); 270 if (s->addr != addr) { 271 if (CK_LIST_EMPTY(&gs->list)) { 272 CK_LIST_REMOVE(gs, chain); 273 soclose(gs->so); 274 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx); 275 } 276 gs = sc->gre_so = NULL; 277 } 278 } 279 280 if (gs == NULL) { 281 /* 282 * Check that socket for given address is already 283 * configured. 284 */ 285 gs = in_gre_lookup_socket(addr); 286 if (gs == NULL) { 287 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO); 288 s->addr = addr; 289 gs = &s->base; 290 291 error = socreate(sc->gre_family, &gs->so, 292 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred, 293 curthread); 294 if (error != 0) { 295 if_printf(GRE2IFP(sc), 296 "cannot create socket: %d\n", error); 297 free(s, M_GRE); 298 return (error); 299 } 300 301 error = udp_set_kernel_tunneling(gs->so, 302 in_gre_udp_input, NULL, gs); 303 if (error != 0) { 304 if_printf(GRE2IFP(sc), 305 "cannot set UDP tunneling: %d\n", error); 306 goto fail; 307 } 308 309 memset(&sopt, 0, sizeof(sopt)); 310 sopt.sopt_dir = SOPT_SET; 311 sopt.sopt_level = IPPROTO_IP; 312 sopt.sopt_name = IP_BINDANY; 313 sopt.sopt_val = &value; 314 sopt.sopt_valsize = sizeof(value); 315 value = 1; 316 error = sosetopt(gs->so, &sopt); 317 if (error != 0) { 318 if_printf(GRE2IFP(sc), 319 "cannot set IP_BINDANY opt: %d\n", error); 320 goto fail; 321 } 322 323 memset(&sin, 0, sizeof(sin)); 324 sin.sin_family = AF_INET; 325 sin.sin_len = sizeof(sin); 326 sin.sin_addr.s_addr = addr; 327 sin.sin_port = htons(GRE_UDPPORT); 328 error = sobind(gs->so, (struct sockaddr *)&sin, 329 curthread); 330 if (error != 0) { 331 if_printf(GRE2IFP(sc), 332 "cannot bind socket: %d\n", error); 333 goto fail; 334 } 335 /* Add socket to the chain */ 336 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain); 337 } 338 } 339 340 /* Add softc to the socket's list */ 341 CK_LIST_INSERT_HEAD(&gs->list, sc, chain); 342 sc->gre_so = gs; 343 return (0); 344 fail: 345 soclose(gs->so); 346 free(s, M_GRE); 347 return (error); 348 } 349 350 static int 351 in_gre_attach(struct gre_softc *sc) 352 { 353 struct epoch_tracker et; 354 struct grehdr *gh; 355 int error; 356 357 if (sc->gre_options & GRE_UDPENCAP) { 358 sc->gre_csumflags = CSUM_UDP; 359 sc->gre_hlen = sizeof(struct greudp); 360 sc->gre_oip.ip_p = IPPROTO_UDP; 361 gh = &sc->gre_udphdr->gi_gre; 362 gre_update_udphdr(sc, &sc->gre_udp, 363 in_pseudo(sc->gre_oip.ip_src.s_addr, 364 sc->gre_oip.ip_dst.s_addr, 0)); 365 } else { 366 sc->gre_hlen = sizeof(struct greip); 367 sc->gre_oip.ip_p = IPPROTO_GRE; 368 gh = &sc->gre_iphdr->gi_gre; 369 } 370 sc->gre_oip.ip_v = IPVERSION; 371 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2; 372 gre_update_hdr(sc, gh); 373 374 /* 375 * If we return error, this means that sc is not linked, 376 * and caller should reset gre_family and free(sc->gre_hdr). 377 */ 378 if (sc->gre_options & GRE_UDPENCAP) { 379 error = in_gre_setup_socket(sc); 380 if (error != 0) 381 return (error); 382 } else 383 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain); 384 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr), 385 sc, srchash); 386 387 /* Set IFF_DRV_RUNNING if interface is ready */ 388 NET_EPOCH_ENTER(et); 389 in_gre_set_running(sc); 390 NET_EPOCH_EXIT(et); 391 return (0); 392 } 393 394 int 395 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value) 396 { 397 int error; 398 399 /* NOTE: we are protected with gre_ioctl_sx lock */ 400 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT); 401 MPASS(sc->gre_family == AF_INET); 402 403 /* 404 * If we are going to change encapsulation protocol, do check 405 * for duplicate tunnels. Return EEXIST here to do not confuse 406 * user. 407 */ 408 if (cmd == GRESOPTS && 409 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) && 410 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr, 411 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL) 412 return (EEXIST); 413 414 CK_LIST_REMOVE(sc, chain); 415 CK_LIST_REMOVE(sc, srchash); 416 GRE_WAIT(); 417 switch (cmd) { 418 case GRESKEY: 419 sc->gre_key = value; 420 break; 421 case GRESOPTS: 422 sc->gre_options = value; 423 break; 424 case GRESPORT: 425 sc->gre_port = value; 426 break; 427 } 428 error = in_gre_attach(sc); 429 if (error != 0) { 430 sc->gre_family = 0; 431 free(sc->gre_hdr, M_GRE); 432 } 433 return (error); 434 } 435 436 int 437 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data) 438 { 439 struct ifreq *ifr = (struct ifreq *)data; 440 struct sockaddr_in *dst, *src; 441 struct ip *ip; 442 int error; 443 444 /* NOTE: we are protected with gre_ioctl_sx lock */ 445 error = EINVAL; 446 switch (cmd) { 447 case SIOCSIFPHYADDR: 448 src = &((struct in_aliasreq *)data)->ifra_addr; 449 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 450 451 /* sanity checks */ 452 if (src->sin_family != dst->sin_family || 453 src->sin_family != AF_INET || 454 src->sin_len != dst->sin_len || 455 src->sin_len != sizeof(*src)) 456 break; 457 if (src->sin_addr.s_addr == INADDR_ANY || 458 dst->sin_addr.s_addr == INADDR_ANY) { 459 error = EADDRNOTAVAIL; 460 break; 461 } 462 if (V_ipv4_hashtbl == NULL) { 463 V_ipv4_hashtbl = gre_hashinit(); 464 V_ipv4_srchashtbl = gre_hashinit(); 465 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit(); 466 } 467 error = in_gre_checkdup(sc, src->sin_addr.s_addr, 468 dst->sin_addr.s_addr, sc->gre_options); 469 if (error == EADDRNOTAVAIL) 470 break; 471 if (error == EEXIST) { 472 /* Addresses are the same. Just return. */ 473 error = 0; 474 break; 475 } 476 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t), 477 M_GRE, M_WAITOK | M_ZERO); 478 ip->ip_src.s_addr = src->sin_addr.s_addr; 479 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 480 if (sc->gre_family != 0) { 481 /* Detach existing tunnel first */ 482 CK_LIST_REMOVE(sc, chain); 483 CK_LIST_REMOVE(sc, srchash); 484 GRE_WAIT(); 485 free(sc->gre_hdr, M_GRE); 486 /* XXX: should we notify about link state change? */ 487 } 488 sc->gre_family = AF_INET; 489 sc->gre_hdr = ip; 490 sc->gre_oseq = 0; 491 sc->gre_iseq = UINT32_MAX; 492 error = in_gre_attach(sc); 493 if (error != 0) { 494 sc->gre_family = 0; 495 free(sc->gre_hdr, M_GRE); 496 } 497 break; 498 case SIOCGIFPSRCADDR: 499 case SIOCGIFPDSTADDR: 500 if (sc->gre_family != AF_INET) { 501 error = EADDRNOTAVAIL; 502 break; 503 } 504 src = (struct sockaddr_in *)&ifr->ifr_addr; 505 memset(src, 0, sizeof(*src)); 506 src->sin_family = AF_INET; 507 src->sin_len = sizeof(*src); 508 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 509 sc->gre_oip.ip_src: sc->gre_oip.ip_dst; 510 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 511 if (error != 0) 512 memset(src, 0, sizeof(*src)); 513 break; 514 } 515 return (error); 516 } 517 518 int 519 in_gre_output(struct mbuf *m, int af, int hlen) 520 { 521 struct greip *gi; 522 523 gi = mtod(m, struct greip *); 524 switch (af) { 525 case AF_INET: 526 /* 527 * gre_transmit() has used M_PREPEND() that doesn't guarantee 528 * m_data is contiguous more than hlen bytes. Use m_copydata() 529 * here to avoid m_pullup(). 530 */ 531 m_copydata(m, hlen + offsetof(struct ip, ip_tos), 532 sizeof(u_char), &gi->gi_ip.ip_tos); 533 m_copydata(m, hlen + offsetof(struct ip, ip_id), 534 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id); 535 break; 536 #ifdef INET6 537 case AF_INET6: 538 gi->gi_ip.ip_tos = 0; /* XXX */ 539 ip_fillid(&gi->gi_ip); 540 break; 541 #endif 542 } 543 gi->gi_ip.ip_ttl = V_ip_gre_ttl; 544 gi->gi_ip.ip_len = htons(m->m_pkthdr.len); 545 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL)); 546 } 547 548 static const struct srcaddrtab *ipv4_srcaddrtab = NULL; 549 static const struct encaptab *ecookie = NULL; 550 static const struct encap_config ipv4_encap_cfg = { 551 .proto = IPPROTO_GRE, 552 .min_length = sizeof(struct greip) + sizeof(struct ip), 553 .exact_match = ENCAP_DRV_LOOKUP, 554 .lookup = in_gre_lookup, 555 .input = gre_input 556 }; 557 558 void 559 in_gre_init(void) 560 { 561 562 if (!IS_DEFAULT_VNET(curvnet)) 563 return; 564 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr, 565 NULL, M_WAITOK); 566 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK); 567 } 568 569 void 570 in_gre_uninit(void) 571 { 572 573 if (IS_DEFAULT_VNET(curvnet)) { 574 ip_encap_detach(ecookie); 575 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 576 } 577 if (V_ipv4_hashtbl != NULL) { 578 gre_hashdestroy(V_ipv4_hashtbl); 579 V_ipv4_hashtbl = NULL; 580 GRE_WAIT(); 581 gre_hashdestroy(V_ipv4_srchashtbl); 582 gre_hashdestroy((struct gre_list *)V_ipv4_sockets); 583 } 584 } 585