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 gre_socket *gs; 227 struct gre_softc *sc; 228 in_addr_t dst; 229 230 NET_EPOCH_ASSERT(); 231 232 gs = (struct gre_socket *)ctx; 233 dst = ((const struct sockaddr_in *)sa)->sin_addr.s_addr; 234 CK_LIST_FOREACH(sc, &gs->list, chain) { 235 if (sc->gre_oip.ip_dst.s_addr == dst) 236 break; 237 } 238 if (sc != NULL && (GRE2IFP(sc)->if_flags & IFF_UP) != 0){ 239 gre_input(m, off + sizeof(struct udphdr), IPPROTO_UDP, sc); 240 return; 241 } 242 m_freem(m); 243 } 244 245 static int 246 in_gre_setup_socket(struct gre_softc *sc) 247 { 248 struct sockopt sopt; 249 struct sockaddr_in sin; 250 struct in_gre_socket *s; 251 struct gre_socket *gs; 252 in_addr_t addr; 253 int error, value; 254 255 /* 256 * NOTE: we are protected with gre_ioctl_sx lock. 257 * 258 * First check that socket is already configured. 259 * If so, check that source addres was not changed. 260 * If address is different, check that there are no other tunnels 261 * and close socket. 262 */ 263 addr = sc->gre_oip.ip_src.s_addr; 264 gs = sc->gre_so; 265 if (gs != NULL) { 266 s = __containerof(gs, struct in_gre_socket, base); 267 if (s->addr != addr) { 268 if (CK_LIST_EMPTY(&gs->list)) { 269 CK_LIST_REMOVE(gs, chain); 270 soclose(gs->so); 271 NET_EPOCH_CALL(gre_sofree, &gs->epoch_ctx); 272 } 273 gs = sc->gre_so = NULL; 274 } 275 } 276 277 if (gs == NULL) { 278 /* 279 * Check that socket for given address is already 280 * configured. 281 */ 282 gs = in_gre_lookup_socket(addr); 283 if (gs == NULL) { 284 s = malloc(sizeof(*s), M_GRE, M_WAITOK | M_ZERO); 285 s->addr = addr; 286 gs = &s->base; 287 288 error = socreate(sc->gre_family, &gs->so, 289 SOCK_DGRAM, IPPROTO_UDP, curthread->td_ucred, 290 curthread); 291 if (error != 0) { 292 if_printf(GRE2IFP(sc), 293 "cannot create socket: %d\n", error); 294 free(s, M_GRE); 295 return (error); 296 } 297 298 error = udp_set_kernel_tunneling(gs->so, 299 in_gre_udp_input, NULL, gs); 300 if (error != 0) { 301 if_printf(GRE2IFP(sc), 302 "cannot set UDP tunneling: %d\n", error); 303 goto fail; 304 } 305 306 memset(&sopt, 0, sizeof(sopt)); 307 sopt.sopt_dir = SOPT_SET; 308 sopt.sopt_level = IPPROTO_IP; 309 sopt.sopt_name = IP_BINDANY; 310 sopt.sopt_val = &value; 311 sopt.sopt_valsize = sizeof(value); 312 value = 1; 313 error = sosetopt(gs->so, &sopt); 314 if (error != 0) { 315 if_printf(GRE2IFP(sc), 316 "cannot set IP_BINDANY opt: %d\n", error); 317 goto fail; 318 } 319 320 memset(&sin, 0, sizeof(sin)); 321 sin.sin_family = AF_INET; 322 sin.sin_len = sizeof(sin); 323 sin.sin_addr.s_addr = addr; 324 sin.sin_port = htons(GRE_UDPPORT); 325 error = sobind(gs->so, (struct sockaddr *)&sin, 326 curthread); 327 if (error != 0) { 328 if_printf(GRE2IFP(sc), 329 "cannot bind socket: %d\n", error); 330 goto fail; 331 } 332 /* Add socket to the chain */ 333 CK_LIST_INSERT_HEAD(&GRE_SOCKHASH(addr), gs, chain); 334 } 335 } 336 337 /* Add softc to the socket's list */ 338 CK_LIST_INSERT_HEAD(&gs->list, sc, chain); 339 sc->gre_so = gs; 340 return (0); 341 fail: 342 soclose(gs->so); 343 free(s, M_GRE); 344 return (error); 345 } 346 347 static int 348 in_gre_attach(struct gre_softc *sc) 349 { 350 struct epoch_tracker et; 351 struct grehdr *gh; 352 int error; 353 354 if (sc->gre_options & GRE_UDPENCAP) { 355 sc->gre_csumflags = CSUM_UDP; 356 sc->gre_hlen = sizeof(struct greudp); 357 sc->gre_oip.ip_p = IPPROTO_UDP; 358 gh = &sc->gre_udphdr->gi_gre; 359 gre_update_udphdr(sc, &sc->gre_udp, 360 in_pseudo(sc->gre_oip.ip_src.s_addr, 361 sc->gre_oip.ip_dst.s_addr, 0)); 362 } else { 363 sc->gre_hlen = sizeof(struct greip); 364 sc->gre_oip.ip_p = IPPROTO_GRE; 365 gh = &sc->gre_iphdr->gi_gre; 366 } 367 sc->gre_oip.ip_v = IPVERSION; 368 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2; 369 gre_update_hdr(sc, gh); 370 371 /* 372 * If we return error, this means that sc is not linked, 373 * and caller should reset gre_family and free(sc->gre_hdr). 374 */ 375 if (sc->gre_options & GRE_UDPENCAP) { 376 error = in_gre_setup_socket(sc); 377 if (error != 0) 378 return (error); 379 } else 380 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain); 381 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr), 382 sc, srchash); 383 384 /* Set IFF_DRV_RUNNING if interface is ready */ 385 NET_EPOCH_ENTER(et); 386 in_gre_set_running(sc); 387 NET_EPOCH_EXIT(et); 388 return (0); 389 } 390 391 int 392 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value) 393 { 394 int error; 395 396 /* NOTE: we are protected with gre_ioctl_sx lock */ 397 MPASS(cmd == GRESKEY || cmd == GRESOPTS || cmd == GRESPORT); 398 MPASS(sc->gre_family == AF_INET); 399 400 /* 401 * If we are going to change encapsulation protocol, do check 402 * for duplicate tunnels. Return EEXIST here to do not confuse 403 * user. 404 */ 405 if (cmd == GRESOPTS && 406 (sc->gre_options & GRE_UDPENCAP) != (value & GRE_UDPENCAP) && 407 in_gre_checkdup(sc, sc->gre_oip.ip_src.s_addr, 408 sc->gre_oip.ip_dst.s_addr, value) == EADDRNOTAVAIL) 409 return (EEXIST); 410 411 CK_LIST_REMOVE(sc, chain); 412 CK_LIST_REMOVE(sc, srchash); 413 GRE_WAIT(); 414 switch (cmd) { 415 case GRESKEY: 416 sc->gre_key = value; 417 break; 418 case GRESOPTS: 419 sc->gre_options = value; 420 break; 421 case GRESPORT: 422 sc->gre_port = value; 423 break; 424 } 425 error = in_gre_attach(sc); 426 if (error != 0) { 427 sc->gre_family = 0; 428 free(sc->gre_hdr, M_GRE); 429 } 430 return (error); 431 } 432 433 int 434 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data) 435 { 436 struct ifreq *ifr = (struct ifreq *)data; 437 struct sockaddr_in *dst, *src; 438 struct ip *ip; 439 int error; 440 441 /* NOTE: we are protected with gre_ioctl_sx lock */ 442 error = EINVAL; 443 switch (cmd) { 444 case SIOCSIFPHYADDR: 445 src = &((struct in_aliasreq *)data)->ifra_addr; 446 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 447 448 /* sanity checks */ 449 if (src->sin_family != dst->sin_family || 450 src->sin_family != AF_INET || 451 src->sin_len != dst->sin_len || 452 src->sin_len != sizeof(*src)) 453 break; 454 if (src->sin_addr.s_addr == INADDR_ANY || 455 dst->sin_addr.s_addr == INADDR_ANY) { 456 error = EADDRNOTAVAIL; 457 break; 458 } 459 if (V_ipv4_hashtbl == NULL) { 460 V_ipv4_hashtbl = gre_hashinit(); 461 V_ipv4_srchashtbl = gre_hashinit(); 462 V_ipv4_sockets = (struct gre_sockets *)gre_hashinit(); 463 } 464 error = in_gre_checkdup(sc, src->sin_addr.s_addr, 465 dst->sin_addr.s_addr, sc->gre_options); 466 if (error == EADDRNOTAVAIL) 467 break; 468 if (error == EEXIST) { 469 /* Addresses are the same. Just return. */ 470 error = 0; 471 break; 472 } 473 ip = malloc(sizeof(struct greudp) + 3 * sizeof(uint32_t), 474 M_GRE, M_WAITOK | M_ZERO); 475 ip->ip_src.s_addr = src->sin_addr.s_addr; 476 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 477 if (sc->gre_family != 0) { 478 /* Detach existing tunnel first */ 479 CK_LIST_REMOVE(sc, chain); 480 CK_LIST_REMOVE(sc, srchash); 481 GRE_WAIT(); 482 free(sc->gre_hdr, M_GRE); 483 /* XXX: should we notify about link state change? */ 484 } 485 sc->gre_family = AF_INET; 486 sc->gre_hdr = ip; 487 sc->gre_oseq = 0; 488 sc->gre_iseq = UINT32_MAX; 489 error = in_gre_attach(sc); 490 if (error != 0) { 491 sc->gre_family = 0; 492 free(sc->gre_hdr, M_GRE); 493 } 494 break; 495 case SIOCGIFPSRCADDR: 496 case SIOCGIFPDSTADDR: 497 if (sc->gre_family != AF_INET) { 498 error = EADDRNOTAVAIL; 499 break; 500 } 501 src = (struct sockaddr_in *)&ifr->ifr_addr; 502 memset(src, 0, sizeof(*src)); 503 src->sin_family = AF_INET; 504 src->sin_len = sizeof(*src); 505 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 506 sc->gre_oip.ip_src: sc->gre_oip.ip_dst; 507 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 508 if (error != 0) 509 memset(src, 0, sizeof(*src)); 510 break; 511 } 512 return (error); 513 } 514 515 int 516 in_gre_output(struct mbuf *m, int af, int hlen) 517 { 518 struct greip *gi; 519 520 gi = mtod(m, struct greip *); 521 switch (af) { 522 case AF_INET: 523 /* 524 * gre_transmit() has used M_PREPEND() that doesn't guarantee 525 * m_data is contiguous more than hlen bytes. Use m_copydata() 526 * here to avoid m_pullup(). 527 */ 528 m_copydata(m, hlen + offsetof(struct ip, ip_tos), 529 sizeof(u_char), &gi->gi_ip.ip_tos); 530 m_copydata(m, hlen + offsetof(struct ip, ip_id), 531 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id); 532 break; 533 #ifdef INET6 534 case AF_INET6: 535 gi->gi_ip.ip_tos = 0; /* XXX */ 536 ip_fillid(&gi->gi_ip); 537 break; 538 #endif 539 } 540 gi->gi_ip.ip_ttl = V_ip_gre_ttl; 541 gi->gi_ip.ip_len = htons(m->m_pkthdr.len); 542 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL)); 543 } 544 545 static const struct srcaddrtab *ipv4_srcaddrtab = NULL; 546 static const struct encaptab *ecookie = NULL; 547 static const struct encap_config ipv4_encap_cfg = { 548 .proto = IPPROTO_GRE, 549 .min_length = sizeof(struct greip) + sizeof(struct ip), 550 .exact_match = ENCAP_DRV_LOOKUP, 551 .lookup = in_gre_lookup, 552 .input = gre_input 553 }; 554 555 void 556 in_gre_init(void) 557 { 558 559 if (!IS_DEFAULT_VNET(curvnet)) 560 return; 561 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr, 562 NULL, M_WAITOK); 563 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK); 564 } 565 566 void 567 in_gre_uninit(void) 568 { 569 570 if (IS_DEFAULT_VNET(curvnet)) { 571 ip_encap_detach(ecookie); 572 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 573 } 574 if (V_ipv4_hashtbl != NULL) { 575 gre_hashdestroy(V_ipv4_hashtbl); 576 V_ipv4_hashtbl = NULL; 577 GRE_WAIT(); 578 gre_hashdestroy(V_ipv4_srchashtbl); 579 gre_hashdestroy((struct gre_list *)V_ipv4_sockets); 580 } 581 } 582