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 #include "opt_inet.h" 37 #include "opt_inet6.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/jail.h> 42 #include <sys/socket.h> 43 #include <sys/sockio.h> 44 #include <sys/mbuf.h> 45 #include <sys/errno.h> 46 #include <sys/kernel.h> 47 #include <sys/sysctl.h> 48 #include <sys/malloc.h> 49 #include <sys/proc.h> 50 51 #include <net/ethernet.h> 52 #include <net/if.h> 53 #include <net/if_var.h> 54 #include <net/if_private.h> 55 #include <net/route.h> 56 #include <net/vnet.h> 57 58 #include <netinet/in.h> 59 #include <netinet/in_systm.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_var.h> 62 #include <netinet/in_var.h> 63 #include <netinet/ip_encap.h> 64 #include <netinet/ip_ecn.h> 65 #include <netinet/in_fib.h> 66 67 #ifdef INET6 68 #include <netinet/ip6.h> 69 #endif 70 71 #include <net/if_gif.h> 72 73 #define GIF_TTL 30 74 VNET_DEFINE_STATIC(int, ip_gif_ttl) = GIF_TTL; 75 #define V_ip_gif_ttl VNET(ip_gif_ttl) 76 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW, 77 &VNET_NAME(ip_gif_ttl), 0, "Default TTL value for encapsulated packets"); 78 79 /* 80 * We keep interfaces in a hash table using src+dst as key. 81 * Interfaces with GIF_IGNORE_SOURCE flag are linked into plain list. 82 */ 83 VNET_DEFINE_STATIC(struct gif_list *, ipv4_hashtbl) = NULL; 84 VNET_DEFINE_STATIC(struct gif_list *, ipv4_srchashtbl) = NULL; 85 VNET_DEFINE_STATIC(struct gif_list, ipv4_list) = CK_LIST_HEAD_INITIALIZER(); 86 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 87 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 88 #define V_ipv4_list VNET(ipv4_list) 89 90 #define GIF_HASH(src, dst) (V_ipv4_hashtbl[\ 91 in_gif_hashval((src), (dst)) & (GIF_HASH_SIZE - 1)]) 92 #define GIF_SRCHASH(src) (V_ipv4_srchashtbl[\ 93 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GIF_HASH_SIZE - 1)]) 94 #define GIF_HASH_SC(sc) GIF_HASH((sc)->gif_iphdr->ip_src.s_addr,\ 95 (sc)->gif_iphdr->ip_dst.s_addr) 96 static uint32_t 97 in_gif_hashval(in_addr_t src, in_addr_t dst) 98 { 99 uint32_t ret; 100 101 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 102 return (fnv_32_buf(&dst, sizeof(dst), ret)); 103 } 104 105 static int 106 in_gif_checkdup(const struct gif_softc *sc, in_addr_t src, in_addr_t dst) 107 { 108 struct gif_softc *tmp; 109 110 if (sc->gif_family == AF_INET && 111 sc->gif_iphdr->ip_src.s_addr == src && 112 sc->gif_iphdr->ip_dst.s_addr == dst) 113 return (EEXIST); 114 115 CK_LIST_FOREACH(tmp, &GIF_HASH(src, dst), chain) { 116 if (tmp == sc) 117 continue; 118 if (tmp->gif_iphdr->ip_src.s_addr == src && 119 tmp->gif_iphdr->ip_dst.s_addr == dst) 120 return (EADDRNOTAVAIL); 121 } 122 return (0); 123 } 124 125 /* 126 * Check that ingress address belongs to local host. 127 */ 128 static void 129 in_gif_set_running(struct gif_softc *sc) 130 { 131 132 if (in_localip(sc->gif_iphdr->ip_src)) 133 GIF2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 134 else 135 GIF2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 136 } 137 138 /* 139 * ifaddr_event handler. 140 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 141 * source address spoofing. 142 */ 143 static void 144 in_gif_srcaddr(void *arg __unused, const struct sockaddr *sa, 145 int event __unused) 146 { 147 const struct sockaddr_in *sin; 148 struct gif_softc *sc; 149 150 /* Check that VNET is ready */ 151 if (V_ipv4_hashtbl == NULL) 152 return; 153 154 NET_EPOCH_ASSERT(); 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 epoch_tracker et; 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 NET_EPOCH_ENTER(et); 249 in_gif_set_running(sc); 250 NET_EPOCH_EXIT(et); 251 break; 252 case SIOCGIFPSRCADDR: 253 case SIOCGIFPDSTADDR: 254 if (sc->gif_family != AF_INET) { 255 error = EADDRNOTAVAIL; 256 break; 257 } 258 src = (struct sockaddr_in *)&ifr->ifr_addr; 259 memset(src, 0, sizeof(*src)); 260 src->sin_family = AF_INET; 261 src->sin_len = sizeof(*src); 262 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 263 sc->gif_iphdr->ip_src: sc->gif_iphdr->ip_dst; 264 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 265 if (error != 0) 266 memset(src, 0, sizeof(*src)); 267 break; 268 } 269 return (error); 270 } 271 272 int 273 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn) 274 { 275 struct gif_softc *sc = ifp->if_softc; 276 struct ip *ip; 277 278 /* prepend new IP header */ 279 NET_EPOCH_ASSERT(); 280 M_PREPEND(m, sizeof(struct ip), M_NOWAIT); 281 if (m == NULL) 282 return (ENOBUFS); 283 ip = mtod(m, struct ip *); 284 285 MPASS(sc->gif_family == AF_INET); 286 memcpy(ip, sc->gif_iphdr, sizeof(struct ip)); 287 ip->ip_p = proto; 288 /* version will be set in ip_output() */ 289 ip->ip_ttl = V_ip_gif_ttl; 290 ip->ip_len = htons(m->m_pkthdr.len); 291 ip->ip_tos = ecn; 292 293 return (ip_output(m, NULL, NULL, 0, NULL, NULL)); 294 } 295 296 static int 297 in_gif_input(struct mbuf *m, int off, int proto, void *arg) 298 { 299 struct gif_softc *sc = arg; 300 struct ifnet *gifp; 301 struct ip *ip; 302 uint8_t ecn; 303 304 NET_EPOCH_ASSERT(); 305 if (sc == NULL) { 306 m_freem(m); 307 KMOD_IPSTAT_INC(ips_nogif); 308 return (IPPROTO_DONE); 309 } 310 gifp = GIF2IFP(sc); 311 if ((gifp->if_flags & IFF_UP) != 0) { 312 ip = mtod(m, struct ip *); 313 ecn = ip->ip_tos; 314 m_adj(m, off); 315 gif_input(m, gifp, proto, ecn); 316 } else { 317 m_freem(m); 318 KMOD_IPSTAT_INC(ips_nogif); 319 } 320 return (IPPROTO_DONE); 321 } 322 323 static int 324 in_gif_lookup(const struct mbuf *m, int off, int proto, void **arg) 325 { 326 const struct ip *ip; 327 struct gif_softc *sc; 328 int ret; 329 330 if (V_ipv4_hashtbl == NULL) 331 return (0); 332 333 NET_EPOCH_ASSERT(); 334 ip = mtod(m, const struct ip *); 335 /* 336 * NOTE: it is safe to iterate without any locking here, because softc 337 * can be reclaimed only when we are not within net_epoch_preempt 338 * section, but ip_encap lookup+input are executed in epoch section. 339 */ 340 ret = 0; 341 CK_LIST_FOREACH(sc, &GIF_HASH(ip->ip_dst.s_addr, 342 ip->ip_src.s_addr), chain) { 343 /* 344 * This is an inbound packet, its ip_dst is source address 345 * in softc. 346 */ 347 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr && 348 sc->gif_iphdr->ip_dst.s_addr == ip->ip_src.s_addr) { 349 ret = ENCAP_DRV_LOOKUP; 350 goto done; 351 } 352 } 353 /* 354 * No exact match. 355 * Check the list of interfaces with GIF_IGNORE_SOURCE flag. 356 */ 357 CK_LIST_FOREACH(sc, &V_ipv4_list, chain) { 358 if (sc->gif_iphdr->ip_src.s_addr == ip->ip_dst.s_addr) { 359 ret = 32 + 8; /* src + proto */ 360 goto done; 361 } 362 } 363 return (0); 364 done: 365 if ((GIF2IFP(sc)->if_flags & IFF_UP) == 0) 366 return (0); 367 /* ingress filters on outer source */ 368 if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) { 369 if (fib4_check_urpf(sc->gif_fibnum, ip->ip_src, 0, NHR_NONE, 370 m->m_pkthdr.rcvif) == 0) 371 return (0); 372 } 373 *arg = sc; 374 return (ret); 375 } 376 377 static const struct srcaddrtab *ipv4_srcaddrtab; 378 static struct { 379 const struct encap_config encap; 380 const struct encaptab *cookie; 381 } ipv4_encap_cfg[] = { 382 { 383 .encap = { 384 .proto = IPPROTO_IPV4, 385 .min_length = 2 * sizeof(struct ip), 386 .exact_match = ENCAP_DRV_LOOKUP, 387 .lookup = in_gif_lookup, 388 .input = in_gif_input 389 }, 390 }, 391 #ifdef INET6 392 { 393 .encap = { 394 .proto = IPPROTO_IPV6, 395 .min_length = sizeof(struct ip) + 396 sizeof(struct ip6_hdr), 397 .exact_match = ENCAP_DRV_LOOKUP, 398 .lookup = in_gif_lookup, 399 .input = in_gif_input 400 }, 401 }, 402 #endif 403 { 404 .encap = { 405 .proto = IPPROTO_ETHERIP, 406 .min_length = sizeof(struct ip) + 407 sizeof(struct etherip_header) + 408 sizeof(struct ether_header), 409 .exact_match = ENCAP_DRV_LOOKUP, 410 .lookup = in_gif_lookup, 411 .input = in_gif_input 412 }, 413 } 414 }; 415 416 void 417 in_gif_init(void) 418 { 419 int i; 420 421 if (!IS_DEFAULT_VNET(curvnet)) 422 return; 423 424 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gif_srcaddr, 425 NULL, M_WAITOK); 426 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 427 ipv4_encap_cfg[i].cookie = ip_encap_attach( 428 &ipv4_encap_cfg[i].encap, NULL, M_WAITOK); 429 } 430 431 void 432 in_gif_uninit(void) 433 { 434 int i; 435 436 if (IS_DEFAULT_VNET(curvnet)) { 437 for (i = 0; i < nitems(ipv4_encap_cfg); i++) 438 ip_encap_detach(ipv4_encap_cfg[i].cookie); 439 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 440 } 441 if (V_ipv4_hashtbl != NULL) { 442 gif_hashdestroy(V_ipv4_hashtbl); 443 V_ipv4_hashtbl = NULL; 444 GIF_WAIT(); 445 gif_hashdestroy(V_ipv4_srchashtbl); 446 } 447 } 448