1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "opt_inet.h" 39 #include "opt_inet6.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/jail.h> 44 #include <sys/socket.h> 45 #include <sys/sockio.h> 46 #include <sys/mbuf.h> 47 #include <sys/errno.h> 48 #include <sys/kernel.h> 49 #include <sys/sysctl.h> 50 #include <sys/malloc.h> 51 #include <sys/proc.h> 52 53 #include <net/ethernet.h> 54 #include <net/if.h> 55 #include <net/if_var.h> 56 #include <net/if_private.h> 57 #include <net/route.h> 58 #include <net/vnet.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_systm.h> 62 #include <netinet/ip.h> 63 #include <netinet/ip_var.h> 64 #include <netinet/in_var.h> 65 #include <netinet/ip_encap.h> 66 #include <netinet/ip_ecn.h> 67 #include <netinet/in_fib.h> 68 69 #ifdef INET6 70 #include <netinet/ip6.h> 71 #endif 72 73 #include <net/if_gif.h> 74 75 #define GIF_TTL 30 76 VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL; 77 #define V_ip_gif_ttl VNET(ip_gif_ttl) 78 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW, 79 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets"); 80 81 /* 82 * We keep interfaces in a hash table using src+dst as key. 83 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list. 84 */ 85 VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL; 86 VNET_DEFINE_STATIC(struct gif_list *, ipv4_srchashtbl) = NULL; 87 VNET_DEFINE_STATIC(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER(); 88 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 89 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 90 #define V_ipv4_list VNET(ipv4_list) 91 92 #define GIF_HASH(src, dst) (V_ipv4_hashtbl[\ 93 in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)]) 94 #define GIF_SRCHASH(src) (V_ipv4_srchashtbl[\ 95 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)]) 96 #define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\ 97 (sc)->gif_iphdr->ip_dst.s_addr) 98 static uint32_t 99 in_gif_hashval(in_addr_t src, in_addr_t dst) 100 { 101 uint32_t ret; 102 103 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 104 return (fnv_32_buf(&dst, sizeof(dst), ret)); 105 } 106 107 static int 108 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst) 109 { 110 struct gif_softc *tmp; 111 112 if (sc->gif_family == AF_INET && 113 sc->gif_iphdr->ip_src.s_addr == src && 114 sc->gif_iphdr->ip_dst.s_addr == dst) 115 return (EEXIST); 116 117 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) { 118 if (tmp == sc) 119 continue; 120 if (tmp->gif_iphdr->ip_src.s_addr == src && 121 tmp->gif_iphdr->ip_dst.s_addr == dst) 122 return (EADDRNOTAVAIL); 123 } 124 return (0); 125 } 126 127 /* 128 * Check that ingress address belongs to local host. 129 */ 130 static void 131 in_gif_set_running(struct gif_softc *sc) 132 { 133 134 if (in_localip(sc->gif_iphdr->ip_src)) 135 GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 136 else 137 GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 138 } 139 140 /* 141 * ifaddr_event handler. 142 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 143 * source address spoofing. 144 */ 145 static void 146 in_gif_srcaddr(void *arg __unused, const struct sockaddr *sa, 147 int event __unused) 148 { 149 const struct sockaddr_in *sin; 150 struct gif_softc *sc; 151 152 /* Check that VNET is ready */ 153 if (V_ipv4_hashtbl == NULL) 154 return; 155 156 NET_EPOCH_ASSERT(); 157 sin = (const struct sockaddr_in *)sa; 158 CK_LIST_FOREACH(sc, &GIF_SRCHASH(sin->sin_addr.s_addr), srchash) { 159 if (sc->gif_iphdr->ip_src.s_addr != sin->sin_addr.s_addr) 160 continue; 161 in_gif_set_running(sc); 162 } 163 } 164 165 static void 166 in_gif_attach(struct gif_softc *sc) 167 { 168 169 if (sc->gif_options & GIF_IGNORE_SOURCE) 170 CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain); 171 else 172 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain); 173 174 CK_LIST_INSERT_HEAD(&GIF_SRCHASH(sc->gif_iphdr->ip_src.s_addr), 175 sc, srchash); 176 } 177 178 int 179 in_gif_setopts(struct gif_softc *sc, u_int options) 180 { 181 182 /* NOTE: we are protected with gif_ioctl_sx lock */ 183 MPASS(sc->gif_family == AF_INET); 184 MPASS(sc->gif_options != options); 185 186 if ((options & GIF_IGNORE_SOURCE) != 187 (sc->gif_options & GIF_IGNORE_SOURCE)) { 188 CK_LIST_REMOVE(sc, srchash); 189 CK_LIST_REMOVE(sc, chain); 190 sc->gif_options = options; 191 in_gif_attach(sc); 192 } 193 return (0); 194 } 195 196 int 197 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data) 198 { 199 struct ifreq *ifr = (struct ifreq *)data; 200 struct epoch_tracker et; 201 struct sockaddr_in *dst, *src; 202 struct ip *ip; 203 int error; 204 205 /* NOTE: we are protected with gif_ioctl_sx lock */ 206 error = EINVAL; 207 switch (cmd) { 208 case SIOCSIFPHYADDR: 209 src = &((struct in_aliasreq *)data)->ifra_addr; 210 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 211 212 /* sanity checks */ 213 if (src->sin_family != dst->sin_family || 214 src->sin_family != AF_INET || 215 src->sin_len != dst->sin_len || 216 src->sin_len != sizeof(*src)) 217 break; 218 if (src->sin_addr.s_addr == INADDR_ANY || 219 dst->sin_addr.s_addr == INADDR_ANY) { 220 error = EADDRNOTAVAIL; 221 break; 222 } 223 if (V_ipv4_hashtbl == NULL) { 224 V_ipv4_hashtbl = gif_hashinit(); 225 V_ipv4_srchashtbl = gif_hashinit(); 226 } 227 error = in_gif_checkdup(sc, src->sin_addr.s_addr, 228 dst->sin_addr.s_addr); 229 if (error == EADDRNOTAVAIL) 230 break; 231 if (error == EEXIST) { 232 /* Addresses are the same. Just return. */ 233 error = 0; 234 break; 235 } 236 ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO); 237 ip->ip_src.s_addr = src->sin_addr.s_addr; 238 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 239 if (sc->gif_family != 0) { 240 /* Detach existing tunnel first */ 241 CK_LIST_REMOVE(sc, srchash); 242 CK_LIST_REMOVE(sc, chain); 243 GIF_WAIT(); 244 free(sc->gif_hdr, M_GIF); 245 /* XXX: should we notify about link state change? */ 246 } 247 sc->gif_family = AF_INET; 248 sc->gif_iphdr = ip; 249 in_gif_attach(sc); 250 NET_EPOCH_ENTER(et); 251 in_gif_set_running(sc); 252 NET_EPOCH_EXIT(et); 253 break; 254 case SIOCGIFPSRCADDR: 255 case SIOCGIFPDSTADDR: 256 if (sc->gif_family != AF_INET) { 257 error = EADDRNOTAVAIL; 258 break; 259 } 260 src = (struct sockaddr_in *)&ifr->ifr_addr; 261 memset(src, 0, sizeof(*src)); 262 src->sin_family = AF_INET; 263 src->sin_len = sizeof(*src); 264 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 265 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst; 266 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 267 if (error != 0) 268 memset(src, 0, sizeof(*src)); 269 break; 270 } 271 return (error); 272 } 273 274 int 275 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn) 276 { 277 struct gif_softc *sc = ifp->if_softc; 278 struct ip *ip; 279 int len; 280 281 /* prepend new IP header */ 282 NET_EPOCH_ASSERT(); 283 len = sizeof(struct ip); 284 #ifndef __NO_STRICT_ALIGNMENT 285 if (proto == IPPROTO_ETHERIP) 286 len += ETHERIP_ALIGN; 287 #endif 288 M_PREPEND(m, len, M_NOWAIT); 289 if (m == NULL) 290 return (ENOBUFS); 291 #ifndef __NO_STRICT_ALIGNMENT 292 if (proto == IPPROTO_ETHERIP) { 293 len = mtod(m, vm_offset_t) & 3; 294 KASSERT(len == 0 || len == ETHERIP_ALIGN, 295 ("in_gif_output: unexpected misalignment")); 296 m->m_data += len; 297 m->m_len -= ETHERIP_ALIGN; 298 } 299 #endif 300 ip = mtod(m, struct ip *); 301 302 MPASS(sc->gif_family == AF_INET); 303 bcopy(sc->gif_iphdr, ip, sizeof(struct ip)); 304 ip->ip_p = proto; 305 /* version will be set in ip_output() */ 306 ip->ip_ttl = V_ip_gif_ttl; 307 ip->ip_len = htons(m->m_pkthdr.len); 308 ip->ip_tos = ecn; 309 310 return (ip_output(m, NULL, NULL, 0, NULL, NULL)); 311 } 312 313 static int 314 in_gif_input(struct mbuf *m, int off, int proto, void *arg) 315 { 316 struct gif_softc *sc = arg; 317 struct ifnet *gifp; 318 struct ip *ip; 319 uint8_t ecn; 320 321 NET_EPOCH_ASSERT(); 322 if (sc == NULL) { 323 m_freem(m); 324 KMOD_IPSTAT_INC(ips_nogif); 325 return (IPPROTO_DONE); 326 } 327 gifp = GIF2IFP(sc); 328 if ((gifp->if_flags & IFF_UP) != 0) { 329 ip = mtod(m, struct ip *); 330 ecn = ip->ip_tos; 331 m_adj(m, off); 332 gif_input(m, gifp, proto, ecn); 333 } else { 334 m_freem(m); 335 KMOD_IPSTAT_INC(ips_nogif); 336 } 337 return (IPPROTO_DONE); 338 } 339 340 static int 341 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg) 342 { 343 const struct ip *ip; 344 struct gif_softc *sc; 345 int ret; 346 347 if (V_ipv4_hashtbl == NULL) 348 return (0); 349 350 NET_EPOCH_ASSERT(); 351 ip = mtod(m, const struct ip *); 352 /* 353 * NOTE: it is safe to iterate without any locking here, because softc 354 * can be reclaimed only when we are not within net_epoch_preempt 355 * section, but ip_encap lookup+input are executed in epoch section. 356 */ 357 ret = 0; 358 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr, 359 ip->ip_src.s_addr), chain) { 360 /* 361 * This is an inbound packet, its ip_dst is source address 362 * in softc. 363 */ 364 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr && 365 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) { 366 ret = ENCAP_DRV_LOOKUP; 367 goto done; 368 } 369 } 370 /* 371 * No exact match. 372 * Check the list of interfaces with GIF_IGNORE_SOURCE flag. 373 */ 374 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) { 375 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) { 376 ret = 32 + 8; /* src + proto */ 377 goto done; 378 } 379 } 380 return (0); 381 done: 382 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0) 383 return (0); 384 /* ingress filters on outer source */ 385 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) { 386 if (fib4_check_urpf(sc->gif_fibnum, ip->ip_src, 0, NHR_NONE, 387 m->m_pkthdr.rcvif) == 0) 388 return (0); 389 } 390 *arg = sc; 391 return (ret); 392 } 393 394 static const struct srcaddrtab *ipv4_srcaddrtab; 395 static struct { 396 const struct encap_config encap; 397 const struct encaptab *cookie; 398 } ipv4_encap_cfg[] = { 399 { 400 .encap = { 401 .proto = IPPROTO_IPV4, 402 .min_length = 2 * sizeof(struct ip), 403 .exact_match = ENCAP_DRV_LOOKUP, 404 .lookup = in_gif_lookup, 405 .input = in_gif_input 406 }, 407 }, 408 #ifdef INET6 409 { 410 .encap = { 411 .proto = IPPROTO_IPV6, 412 .min_length = sizeof(struct ip) + 413 sizeof(struct ip6_hdr), 414 .exact_match = ENCAP_DRV_LOOKUP, 415 .lookup = in_gif_lookup, 416 .input = in_gif_input 417 }, 418 }, 419 #endif 420 { 421 .encap = { 422 .proto = IPPROTO_ETHERIP, 423 .min_length = sizeof(struct ip) + 424 sizeof(struct etherip_header) + 425 sizeof(struct ether_header), 426 .exact_match = ENCAP_DRV_LOOKUP, 427 .lookup = in_gif_lookup, 428 .input = in_gif_input 429 }, 430 } 431 }; 432 433 void 434 in_gif_init(void) 435 { 436 int i; 437 438 if (!IS_DEFAULT_VNET(curvnet)) 439 return; 440 441 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gif_srcaddr, 442 NULL, M_WAITOK); 443 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 444 ipv4_encap_cfg[i].cookie = ip_encap_attach( 445 &ipv4_encap_cfg[i].encap, NULL, M_WAITOK); 446 } 447 448 void 449 in_gif_uninit(void) 450 { 451 int i; 452 453 if (IS_DEFAULT_VNET(curvnet)) { 454 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 455 ip_encap_detach(ipv4_encap_cfg[i].cookie); 456 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 457 } 458 if (V_ipv4_hashtbl != NULL) { 459 gif_hashdestroy(V_ipv4_hashtbl); 460 V_ipv4_hashtbl = NULL; 461 GIF_WAIT(); 462 gif_hashdestroy(V_ipv4_srchashtbl); 463 } 464 } 465