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 /* Check that VNET is ready */ 152 if (V_ipv4_hashtbl == NULL) 153 return; 154 155 MPASS(in_epoch(net_epoch_preempt)); 156 sin = (const struct sockaddr_in *)sa; 157 CK_LIST_FOREACH(sc, &GIF_SRCHASH(sin->sin_addr.s_addr), srchash) { 158 if (sc->gif_iphdr->ip_src.s_addr != sin->sin_addr.s_addr) 159 continue; 160 in_gif_set_running(sc); 161 } 162 } 163 164 static void 165 in_gif_attach(struct gif_softc *sc) 166 { 167 168 if (sc->gif_options & GIF_IGNORE_SOURCE) 169 CK_LIST_INSERT_HEAD(&V_ipv4_list, sc, chain); 170 else 171 CK_LIST_INSERT_HEAD(&GIF_HASH_SC(sc), sc, chain); 172 173 CK_LIST_INSERT_HEAD(&GIF_SRCHASH(sc->gif_iphdr->ip_src.s_addr), 174 sc, srchash); 175 } 176 177 int 178 in_gif_setopts(struct gif_softc *sc, u_int options) 179 { 180 181 /* NOTE: we are protected with gif_ioctl_sx lock */ 182 MPASS(sc->gif_family == AF_INET); 183 MPASS(sc->gif_options != options); 184 185 if ((options & GIF_IGNORE_SOURCE) != 186 (sc->gif_options & GIF_IGNORE_SOURCE)) { 187 CK_LIST_REMOVE(sc, srchash); 188 CK_LIST_REMOVE(sc, chain); 189 sc->gif_options = options; 190 in_gif_attach(sc); 191 } 192 return (0); 193 } 194 195 int 196 in_gif_ioctl(struct gif_softc *sc, u_long cmd, caddr_t data) 197 { 198 struct ifreq *ifr = (struct ifreq *)data; 199 struct sockaddr_in *dst, *src; 200 struct ip *ip; 201 int error; 202 203 /* NOTE: we are protected with gif_ioctl_sx lock */ 204 error = EINVAL; 205 switch (cmd) { 206 case SIOCSIFPHYADDR: 207 src = &((struct in_aliasreq *)data)->ifra_addr; 208 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 209 210 /* sanity checks */ 211 if (src->sin_family != dst->sin_family || 212 src->sin_family != AF_INET || 213 src->sin_len != dst->sin_len || 214 src->sin_len != sizeof(*src)) 215 break; 216 if (src->sin_addr.s_addr == INADDR_ANY || 217 dst->sin_addr.s_addr == INADDR_ANY) { 218 error = EADDRNOTAVAIL; 219 break; 220 } 221 if (V_ipv4_hashtbl == NULL) { 222 V_ipv4_hashtbl = gif_hashinit(); 223 V_ipv4_srchashtbl = gif_hashinit(); 224 } 225 error = in_gif_checkdup(sc, src->sin_addr.s_addr, 226 dst->sin_addr.s_addr); 227 if (error == EADDRNOTAVAIL) 228 break; 229 if (error == EEXIST) { 230 /* Addresses are the same. Just return. */ 231 error = 0; 232 break; 233 } 234 ip = malloc(sizeof(*ip), M_GIF, M_WAITOK | M_ZERO); 235 ip->ip_src.s_addr = src->sin_addr.s_addr; 236 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 237 if (sc->gif_family != 0) { 238 /* Detach existing tunnel first */ 239 CK_LIST_REMOVE(sc, srchash); 240 CK_LIST_REMOVE(sc, chain); 241 GIF_WAIT(); 242 free(sc->gif_hdr, M_GIF); 243 /* XXX: should we notify about link state change? */ 244 } 245 sc->gif_family = AF_INET; 246 sc->gif_iphdr = ip; 247 in_gif_attach(sc); 248 in_gif_set_running(sc); 249 break; 250 case SIOCGIFPSRCADDR: 251 case SIOCGIFPDSTADDR: 252 if (sc->gif_family != AF_INET) { 253 error = EADDRNOTAVAIL; 254 break; 255 } 256 src = (struct sockaddr_in *)&ifr->ifr_addr; 257 memset(src, 0, sizeof(*src)); 258 src->sin_family = AF_INET; 259 src->sin_len = sizeof(*src); 260 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 261 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst; 262 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 263 if (error != 0) 264 memset(src, 0, sizeof(*src)); 265 break; 266 } 267 return (error); 268 } 269 270 int 271 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn) 272 { 273 struct gif_softc *sc = ifp->if_softc; 274 struct ip *ip; 275 int len; 276 277 /* prepend new IP header */ 278 MPASS(in_epoch(net_epoch_preempt)); 279 len = sizeof(struct ip); 280 #ifndef __NO_STRICT_ALIGNMENT 281 if (proto == IPPROTO_ETHERIP) 282 len += ETHERIP_ALIGN; 283 #endif 284 M_PREPEND(m, len, M_NOWAIT); 285 if (m == NULL) 286 return (ENOBUFS); 287 #ifndef __NO_STRICT_ALIGNMENT 288 if (proto == IPPROTO_ETHERIP) { 289 len = mtod(m, vm_offset_t) & 3; 290 KASSERT(len == 0 || len == ETHERIP_ALIGN, 291 ("in_gif_output: unexpected misalignment")); 292 m->m_data += len; 293 m->m_len -= ETHERIP_ALIGN; 294 } 295 #endif 296 ip = mtod(m, struct ip *); 297 298 MPASS(sc->gif_family == AF_INET); 299 bcopy(sc->gif_iphdr, ip, sizeof(struct ip)); 300 ip->ip_p = proto; 301 /* version will be set in ip_output() */ 302 ip->ip_ttl = V_ip_gif_ttl; 303 ip->ip_len = htons(m->m_pkthdr.len); 304 ip->ip_tos = ecn; 305 306 return (ip_output(m, NULL, NULL, 0, NULL, NULL)); 307 } 308 309 static int 310 in_gif_input(struct mbuf *m, int off, int proto, void *arg) 311 { 312 struct gif_softc *sc = arg; 313 struct ifnet *gifp; 314 struct ip *ip; 315 uint8_t ecn; 316 317 MPASS(in_epoch(net_epoch_preempt)); 318 if (sc == NULL) { 319 m_freem(m); 320 KMOD_IPSTAT_INC(ips_nogif); 321 return (IPPROTO_DONE); 322 } 323 gifp = GIF2IFP(sc); 324 if ((gifp->if_flags & IFF_UP) != 0) { 325 ip = mtod(m, struct ip *); 326 ecn = ip->ip_tos; 327 m_adj(m, off); 328 gif_input(m, gifp, proto, ecn); 329 } else { 330 m_freem(m); 331 KMOD_IPSTAT_INC(ips_nogif); 332 } 333 return (IPPROTO_DONE); 334 } 335 336 static int 337 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg) 338 { 339 const struct ip *ip; 340 struct gif_softc *sc; 341 int ret; 342 343 if (V_ipv4_hashtbl == NULL) 344 return (0); 345 346 MPASS(in_epoch(net_epoch_preempt)); 347 ip = mtod(m, const struct ip *); 348 /* 349 * NOTE: it is safe to iterate without any locking here, because softc 350 * can be reclaimed only when we are not within net_epoch_preempt 351 * section, but ip_encap lookup+input are executed in epoch section. 352 */ 353 ret = 0; 354 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr, 355 ip->ip_src.s_addr), chain) { 356 /* 357 * This is an inbound packet, its ip_dst is source address 358 * in softc. 359 */ 360 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr && 361 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) { 362 ret = ENCAP_DRV_LOOKUP; 363 goto done; 364 } 365 } 366 /* 367 * No exact match. 368 * Check the list of interfaces with GIF_IGNORE_SOURCE flag. 369 */ 370 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) { 371 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) { 372 ret = 32 + 8; /* src + proto */ 373 goto done; 374 } 375 } 376 return (0); 377 done: 378 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0) 379 return (0); 380 /* ingress filters on outer source */ 381 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) { 382 struct nhop4_basic nh4; 383 struct in_addr dst; 384 385 dst = ip->ip_src; 386 if (fib4_lookup_nh_basic(sc->gif_fibnum, dst, 0, 0, &nh4) != 0) 387 return (0); 388 if (nh4.nh_ifp != m->m_pkthdr.rcvif) 389 return (0); 390 } 391 *arg = sc; 392 return (ret); 393 } 394 395 static const struct srcaddrtab *ipv4_srcaddrtab; 396 static struct { 397 const struct encap_config encap; 398 const struct encaptab *cookie; 399 } ipv4_encap_cfg[] = { 400 { 401 .encap = { 402 .proto = IPPROTO_IPV4, 403 .min_length = 2 * sizeof(struct ip), 404 .exact_match = ENCAP_DRV_LOOKUP, 405 .lookup = in_gif_lookup, 406 .input = in_gif_input 407 }, 408 }, 409 #ifdef INET6 410 { 411 .encap = { 412 .proto = IPPROTO_IPV6, 413 .min_length = sizeof(struct ip) + 414 sizeof(struct ip6_hdr), 415 .exact_match = ENCAP_DRV_LOOKUP, 416 .lookup = in_gif_lookup, 417 .input = in_gif_input 418 }, 419 }, 420 #endif 421 { 422 .encap = { 423 .proto = IPPROTO_ETHERIP, 424 .min_length = sizeof(struct ip) + 425 sizeof(struct etherip_header) + 426 sizeof(struct ether_header), 427 .exact_match = ENCAP_DRV_LOOKUP, 428 .lookup = in_gif_lookup, 429 .input = in_gif_input 430 }, 431 } 432 }; 433 434 void 435 in_gif_init(void) 436 { 437 int i; 438 439 if (!IS_DEFAULT_VNET(curvnet)) 440 return; 441 442 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gif_srcaddr, 443 NULL, M_WAITOK); 444 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 445 ipv4_encap_cfg[i].cookie = ip_encap_attach( 446 &ipv4_encap_cfg[i].encap, NULL, M_WAITOK); 447 } 448 449 void 450 in_gif_uninit(void) 451 { 452 int i; 453 454 if (IS_DEFAULT_VNET(curvnet)) { 455 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 456 ip_encap_detach(ipv4_encap_cfg[i].cookie); 457 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 458 } 459 if (V_ipv4_hashtbl != NULL) { 460 gif_hashdestroy(V_ipv4_hashtbl); 461 V_ipv4_hashtbl = NULL; 462 GIF_WAIT(); 463 gif_hashdestroy(V_ipv4_srchashtbl); 464 } 465 } 466 467