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/route.h> 57 #include <net/vnet.h> 58 59 #include <netinet/in.h> 60 #include <netinet/in_systm.h> 61 #include <netinet/ip.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/in_var.h> 64 #include <netinet/ip_encap.h> 65 #include <netinet/ip_ecn.h> 66 #include <netinet/in_fib.h> 67 68 #ifdef INET6 69 #include <netinet/ip6.h> 70 #endif 71 72 #include <net/if_gif.h> 73 74 #define GIF_TTL 30 75 VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL; 76 #define V_ip_gif_ttl VNET(ip_gif_ttl) 77 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW, 78 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets"); 79 80 /* 81 * We keep interfaces in a hash table using src+dst as key. 82 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list. 83 */ 84 VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL; 85 VNET_DEFINE_STATIC(struct gif_list *, ipv4_srchashtbl) = NULL; 86 VNET_DEFINE_STATIC(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER(); 87 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 88 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 89 #define V_ipv4_list VNET(ipv4_list) 90 91 #define GIF_HASH(src, dst) (V_ipv4_hashtbl[\ 92 in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)]) 93 #define GIF_SRCHASH(src) (V_ipv4_srchashtbl[\ 94 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)]) 95 #define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\ 96 (sc)->gif_iphdr->ip_dst.s_addr) 97 static uint32_t 98 in_gif_hashval(in_addr_t src, in_addr_t dst) 99 { 100 uint32_t ret; 101 102 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 103 return (fnv_32_buf(&dst, sizeof(dst), ret)); 104 } 105 106 static int 107 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst) 108 { 109 struct gif_softc *tmp; 110 111 if (sc->gif_family == AF_INET && 112 sc->gif_iphdr->ip_src.s_addr == src && 113 sc->gif_iphdr->ip_dst.s_addr == dst) 114 return (EEXIST); 115 116 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) { 117 if (tmp == sc) 118 continue; 119 if (tmp->gif_iphdr->ip_src.s_addr == src && 120 tmp->gif_iphdr->ip_dst.s_addr == dst) 121 return (EADDRNOTAVAIL); 122 } 123 return (0); 124 } 125 126 /* 127 * Check that ingress address belongs to local host. 128 */ 129 static void 130 in_gif_set_running(struct gif_softc *sc) 131 { 132 133 if (in_localip(sc->gif_iphdr->ip_src)) 134 GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 135 else 136 GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 137 } 138 139 /* 140 * ifaddr_event handler. 141 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 142 * source address spoofing. 143 */ 144 static void 145 in_gif_srcaddr(void *arg __unused, const struct sockaddr *sa, 146 int event __unused) 147 { 148 const struct sockaddr_in *sin; 149 struct gif_softc *sc; 150 151 if (V_ipv4_srchashtbl == NULL) 152 return; 153 154 MPASS(in_epoch(net_epoch_preempt)); 155 sin = (const struct sockaddr_in *)sa; 156 CK_LIST_FOREACH(sc, &GIF_SRCHASH(sin->sin_addr.s_addr), srchash) { 157 if (sc->gif_iphdr->ip_src.s_addr != sin->sin_addr.s_addr) 158 continue; 159 in_gif_set_running(sc); 160 } 161 } 162 163 static void 164 in_gif_attach(struct gif_softc *sc) 165 { 166 167 if (sc->gif_options & GIF_IGNORE_SOURCE) 168 CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain); 169 else 170 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain); 171 172 CK_LIST_INSERT_HEAD(&GIF_SRCHASH(sc->gif_iphdr->ip_src.s_addr), 173 sc, srchash); 174 } 175 176 int 177 in_gif_setopts(struct gif_softc *sc, u_int options) 178 { 179 180 /* NOTE: we are protected with gif_ioctl_sx lock */ 181 MPASS(sc->gif_family == AF_INET); 182 MPASS(sc->gif_options != options); 183 184 if ((options & GIF_IGNORE_SOURCE) != 185 (sc->gif_options & GIF_IGNORE_SOURCE)) { 186 CK_LIST_REMOVE(sc, srchash); 187 CK_LIST_REMOVE(sc, chain); 188 sc->gif_options = options; 189 in_gif_attach(sc); 190 } 191 return (0); 192 } 193 194 int 195 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data) 196 { 197 struct ifreq *ifr = (struct ifreq *)data; 198 struct sockaddr_in *dst, *src; 199 struct ip *ip; 200 int error; 201 202 /* NOTE: we are protected with gif_ioctl_sx lock */ 203 error = EINVAL; 204 switch (cmd) { 205 case SIOCSIFPHYADDR: 206 src = &((struct in_aliasreq *)data)->ifra_addr; 207 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 208 209 /* sanity checks */ 210 if (src->sin_family != dst->sin_family || 211 src->sin_family != AF_INET || 212 src->sin_len != dst->sin_len || 213 src->sin_len != sizeof(*src)) 214 break; 215 if (src->sin_addr.s_addr == INADDR_ANY || 216 dst->sin_addr.s_addr == INADDR_ANY) { 217 error = EADDRNOTAVAIL; 218 break; 219 } 220 if (V_ipv4_hashtbl == NULL) { 221 V_ipv4_hashtbl = gif_hashinit(); 222 V_ipv4_srchashtbl = gif_hashinit(); 223 } 224 error = in_gif_checkdup(sc, src->sin_addr.s_addr, 225 dst->sin_addr.s_addr); 226 if (error == EADDRNOTAVAIL) 227 break; 228 if (error == EEXIST) { 229 /* Addresses are the same. Just return. */ 230 error = 0; 231 break; 232 } 233 ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO); 234 ip->ip_src.s_addr = src->sin_addr.s_addr; 235 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 236 if (sc->gif_family != 0) { 237 /* Detach existing tunnel first */ 238 CK_LIST_REMOVE(sc, srchash); 239 CK_LIST_REMOVE(sc, chain); 240 GIF_WAIT(); 241 free(sc->gif_hdr, M_GIF); 242 /* XXX: should we notify about link state change? */ 243 } 244 sc->gif_family = AF_INET; 245 sc->gif_iphdr = ip; 246 in_gif_attach(sc); 247 in_gif_set_running(sc); 248 break; 249 case SIOCGIFPSRCADDR: 250 case SIOCGIFPDSTADDR: 251 if (sc->gif_family != AF_INET) { 252 error = EADDRNOTAVAIL; 253 break; 254 } 255 src = (struct sockaddr_in *)&ifr->ifr_addr; 256 memset(src, 0, sizeof(*src)); 257 src->sin_family = AF_INET; 258 src->sin_len = sizeof(*src); 259 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 260 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst; 261 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 262 if (error != 0) 263 memset(src, 0, sizeof(*src)); 264 break; 265 } 266 return (error); 267 } 268 269 int 270 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn) 271 { 272 struct gif_softc *sc = ifp->if_softc; 273 struct ip *ip; 274 int len; 275 276 /* prepend new IP header */ 277 MPASS(in_epoch(net_epoch_preempt)); 278 len = sizeof(struct ip); 279 #ifndef __NO_STRICT_ALIGNMENT 280 if (proto == IPPROTO_ETHERIP) 281 len += ETHERIP_ALIGN; 282 #endif 283 M_PREPEND(m, len, M_NOWAIT); 284 if (m == NULL) 285 return (ENOBUFS); 286 #ifndef __NO_STRICT_ALIGNMENT 287 if (proto == IPPROTO_ETHERIP) { 288 len = mtod(m, vm_offset_t) & 3; 289 KASSERT(len == 0 || len == ETHERIP_ALIGN, 290 ("in_gif_output: unexpected misalignment")); 291 m->m_data += len; 292 m->m_len -= ETHERIP_ALIGN; 293 } 294 #endif 295 ip = mtod(m, struct ip *); 296 297 MPASS(sc->gif_family == AF_INET); 298 bcopy(sc->gif_iphdr, ip, sizeof(struct ip)); 299 ip->ip_p = proto; 300 /* version will be set in ip_output() */ 301 ip->ip_ttl = V_ip_gif_ttl; 302 ip->ip_len = htons(m->m_pkthdr.len); 303 ip->ip_tos = ecn; 304 305 return (ip_output(m, NULL, NULL, 0, NULL, NULL)); 306 } 307 308 static int 309 in_gif_input(struct mbuf *m, int off, int proto, void *arg) 310 { 311 struct gif_softc *sc = arg; 312 struct ifnet *gifp; 313 struct ip *ip; 314 uint8_t ecn; 315 316 MPASS(in_epoch(net_epoch_preempt)); 317 if (sc == NULL) { 318 m_freem(m); 319 KMOD_IPSTAT_INC(ips_nogif); 320 return (IPPROTO_DONE); 321 } 322 gifp = GIF2IFP(sc); 323 if ((gifp->if_flags & IFF_UP) != 0) { 324 ip = mtod(m, struct ip *); 325 ecn = ip->ip_tos; 326 m_adj(m, off); 327 gif_input(m, gifp, proto, ecn); 328 } else { 329 m_freem(m); 330 KMOD_IPSTAT_INC(ips_nogif); 331 } 332 return (IPPROTO_DONE); 333 } 334 335 static int 336 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg) 337 { 338 const struct ip *ip; 339 struct gif_softc *sc; 340 int ret; 341 342 if (V_ipv4_hashtbl == NULL) 343 return (0); 344 345 MPASS(in_epoch(net_epoch_preempt)); 346 ip = mtod(m, const struct ip *); 347 /* 348 * NOTE: it is safe to iterate without any locking here, because softc 349 * can be reclaimed only when we are not within net_epoch_preempt 350 * section, but ip_encap lookup+input are executed in epoch section. 351 */ 352 ret = 0; 353 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr, 354 ip->ip_src.s_addr), chain) { 355 /* 356 * This is an inbound packet, its ip_dst is source address 357 * in softc. 358 */ 359 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr && 360 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) { 361 ret = ENCAP_DRV_LOOKUP; 362 goto done; 363 } 364 } 365 /* 366 * No exact match. 367 * Check the list of interfaces with GIF_IGNORE_SOURCE flag. 368 */ 369 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) { 370 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) { 371 ret = 32 + 8; /* src + proto */ 372 goto done; 373 } 374 } 375 return (0); 376 done: 377 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0) 378 return (0); 379 /* ingress filters on outer source */ 380 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) { 381 struct nhop4_basic nh4; 382 struct in_addr dst; 383 384 dst = ip->ip_src; 385 if (fib4_lookup_nh_basic(sc->gif_fibnum, dst, 0, 0, &nh4) != 0) 386 return (0); 387 if (nh4.nh_ifp != m->m_pkthdr.rcvif) 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 gif_hashdestroy(V_ipv4_srchashtbl); 461 } 462 } 463 464