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/sockio.h> 48 #include <sys/mbuf.h> 49 #include <sys/errno.h> 50 #include <sys/kernel.h> 51 #include <sys/sysctl.h> 52 #include <sys/malloc.h> 53 #include <sys/proc.h> 54 55 #include <net/if.h> 56 #include <net/if_var.h> 57 #include <net/vnet.h> 58 59 #include <netinet/in.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip.h> 62 #include <netinet/ip_encap.h> 63 #include <netinet/ip_var.h> 64 65 #ifdef INET6 66 #include <netinet/ip6.h> 67 #endif 68 69 #include <net/if_gre.h> 70 71 #define GRE_TTL 30 72 VNET_DEFINE(int, ip_gre_ttl) = GRE_TTL; 73 #define V_ip_gre_ttl VNET(ip_gre_ttl) 74 SYSCTL_INT(_net_inet_ip, OID_AUTO, grettl, CTLFLAG_VNET | CTLFLAG_RW, 75 &VNET_NAME(ip_gre_ttl), 0, "Default TTL value for encapsulated packets"); 76 77 VNET_DEFINE_STATIC(struct gre_list *, ipv4_hashtbl) = NULL; 78 VNET_DEFINE_STATIC(struct gre_list *, ipv4_srchashtbl) = NULL; 79 #define V_ipv4_hashtbl VNET(ipv4_hashtbl) 80 #define V_ipv4_srchashtbl VNET(ipv4_srchashtbl) 81 #define GRE_HASH(src, dst) (V_ipv4_hashtbl[\ 82 in_gre_hashval((src), (dst)) & (GRE_HASH_SIZE - 1)]) 83 #define GRE_SRCHASH(src) (V_ipv4_srchashtbl[\ 84 fnv_32_buf(&(src), sizeof(src), FNV1_32_INIT) & (GRE_HASH_SIZE - 1)]) 85 #define GRE_HASH_SC(sc) GRE_HASH((sc)->gre_oip.ip_src.s_addr,\ 86 (sc)->gre_oip.ip_dst.s_addr) 87 88 static uint32_t 89 in_gre_hashval(in_addr_t src, in_addr_t dst) 90 { 91 uint32_t ret; 92 93 ret = fnv_32_buf(&src, sizeof(src), FNV1_32_INIT); 94 return (fnv_32_buf(&dst, sizeof(dst), ret)); 95 } 96 97 static int 98 in_gre_checkdup(const struct gre_softc *sc, in_addr_t src, in_addr_t dst) 99 { 100 struct gre_softc *tmp; 101 102 if (sc->gre_family == AF_INET && 103 sc->gre_oip.ip_src.s_addr == src && 104 sc->gre_oip.ip_dst.s_addr == dst) 105 return (EEXIST); 106 107 CK_LIST_FOREACH(tmp, &GRE_HASH(src, dst), chain) { 108 if (tmp == sc) 109 continue; 110 if (tmp->gre_oip.ip_src.s_addr == src && 111 tmp->gre_oip.ip_dst.s_addr == dst) 112 return (EADDRNOTAVAIL); 113 } 114 return (0); 115 } 116 117 static int 118 in_gre_lookup(const struct mbuf *m, int off, int proto, void **arg) 119 { 120 const struct ip *ip; 121 struct gre_softc *sc; 122 123 if (V_ipv4_hashtbl == NULL) 124 return (0); 125 126 MPASS(in_epoch(net_epoch_preempt)); 127 ip = mtod(m, const struct ip *); 128 CK_LIST_FOREACH(sc, &GRE_HASH(ip->ip_dst.s_addr, 129 ip->ip_src.s_addr), chain) { 130 /* 131 * This is an inbound packet, its ip_dst is source address 132 * in softc. 133 */ 134 if (sc->gre_oip.ip_src.s_addr == ip->ip_dst.s_addr && 135 sc->gre_oip.ip_dst.s_addr == ip->ip_src.s_addr) { 136 if ((GRE2IFP(sc)->if_flags & IFF_UP) == 0) 137 return (0); 138 *arg = sc; 139 return (ENCAP_DRV_LOOKUP); 140 } 141 } 142 return (0); 143 } 144 145 /* 146 * Check that ingress address belongs to local host. 147 */ 148 static void 149 in_gre_set_running(struct gre_softc *sc) 150 { 151 152 if (in_localip(sc->gre_oip.ip_src)) 153 GRE2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING; 154 else 155 GRE2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING; 156 } 157 158 /* 159 * ifaddr_event handler. 160 * Clear IFF_DRV_RUNNING flag when ingress address disappears to prevent 161 * source address spoofing. 162 */ 163 static void 164 in_gre_srcaddr(void *arg __unused, const struct sockaddr *sa, 165 int event __unused) 166 { 167 const struct sockaddr_in *sin; 168 struct gre_softc *sc; 169 170 /* Check that VNET is ready */ 171 if (V_ipv4_hashtbl == NULL) 172 return; 173 174 MPASS(in_epoch(net_epoch_preempt)); 175 sin = (const struct sockaddr_in *)sa; 176 CK_LIST_FOREACH(sc, &GRE_SRCHASH(sin->sin_addr.s_addr), srchash) { 177 if (sc->gre_oip.ip_src.s_addr != sin->sin_addr.s_addr) 178 continue; 179 in_gre_set_running(sc); 180 } 181 } 182 183 static void 184 in_gre_attach(struct gre_softc *sc) 185 { 186 187 sc->gre_hlen = sizeof(struct greip); 188 sc->gre_oip.ip_v = IPVERSION; 189 sc->gre_oip.ip_hl = sizeof(struct ip) >> 2; 190 sc->gre_oip.ip_p = IPPROTO_GRE; 191 gre_updatehdr(sc, &sc->gre_gihdr->gi_gre); 192 CK_LIST_INSERT_HEAD(&GRE_HASH_SC(sc), sc, chain); 193 CK_LIST_INSERT_HEAD(&GRE_SRCHASH(sc->gre_oip.ip_src.s_addr), 194 sc, srchash); 195 } 196 197 void 198 in_gre_setopts(struct gre_softc *sc, u_long cmd, uint32_t value) 199 { 200 201 MPASS(cmd == GRESKEY || cmd == GRESOPTS); 202 203 /* NOTE: we are protected with gre_ioctl_sx lock */ 204 MPASS(sc->gre_family == AF_INET); 205 CK_LIST_REMOVE(sc, chain); 206 CK_LIST_REMOVE(sc, srchash); 207 GRE_WAIT(); 208 if (cmd == GRESKEY) 209 sc->gre_key = value; 210 else 211 sc->gre_options = value; 212 in_gre_attach(sc); 213 } 214 215 int 216 in_gre_ioctl(struct gre_softc *sc, u_long cmd, caddr_t data) 217 { 218 struct ifreq *ifr = (struct ifreq *)data; 219 struct sockaddr_in *dst, *src; 220 struct ip *ip; 221 int error; 222 223 /* NOTE: we are protected with gre_ioctl_sx lock */ 224 error = EINVAL; 225 switch (cmd) { 226 case SIOCSIFPHYADDR: 227 src = &((struct in_aliasreq *)data)->ifra_addr; 228 dst = &((struct in_aliasreq *)data)->ifra_dstaddr; 229 230 /* sanity checks */ 231 if (src->sin_family != dst->sin_family || 232 src->sin_family != AF_INET || 233 src->sin_len != dst->sin_len || 234 src->sin_len != sizeof(*src)) 235 break; 236 if (src->sin_addr.s_addr == INADDR_ANY || 237 dst->sin_addr.s_addr == INADDR_ANY) { 238 error = EADDRNOTAVAIL; 239 break; 240 } 241 if (V_ipv4_hashtbl == NULL) { 242 V_ipv4_hashtbl = gre_hashinit(); 243 V_ipv4_srchashtbl = gre_hashinit(); 244 } 245 error = in_gre_checkdup(sc, src->sin_addr.s_addr, 246 dst->sin_addr.s_addr); 247 if (error == EADDRNOTAVAIL) 248 break; 249 if (error == EEXIST) { 250 /* Addresses are the same. Just return. */ 251 error = 0; 252 break; 253 } 254 ip = malloc(sizeof(struct greip) + 3 * sizeof(uint32_t), 255 M_GRE, M_WAITOK | M_ZERO); 256 ip->ip_src.s_addr = src->sin_addr.s_addr; 257 ip->ip_dst.s_addr = dst->sin_addr.s_addr; 258 if (sc->gre_family != 0) { 259 /* Detach existing tunnel first */ 260 CK_LIST_REMOVE(sc, chain); 261 CK_LIST_REMOVE(sc, srchash); 262 GRE_WAIT(); 263 free(sc->gre_hdr, M_GRE); 264 /* XXX: should we notify about link state change? */ 265 } 266 sc->gre_family = AF_INET; 267 sc->gre_hdr = ip; 268 sc->gre_oseq = 0; 269 sc->gre_iseq = UINT32_MAX; 270 in_gre_attach(sc); 271 in_gre_set_running(sc); 272 break; 273 case SIOCGIFPSRCADDR: 274 case SIOCGIFPDSTADDR: 275 if (sc->gre_family != AF_INET) { 276 error = EADDRNOTAVAIL; 277 break; 278 } 279 src = (struct sockaddr_in *)&ifr->ifr_addr; 280 memset(src, 0, sizeof(*src)); 281 src->sin_family = AF_INET; 282 src->sin_len = sizeof(*src); 283 src->sin_addr = (cmd == SIOCGIFPSRCADDR) ? 284 sc->gre_oip.ip_src: sc->gre_oip.ip_dst; 285 error = prison_if(curthread->td_ucred, (struct sockaddr *)src); 286 if (error != 0) 287 memset(src, 0, sizeof(*src)); 288 break; 289 } 290 return (error); 291 } 292 293 int 294 in_gre_output(struct mbuf *m, int af, int hlen) 295 { 296 struct greip *gi; 297 298 gi = mtod(m, struct greip *); 299 switch (af) { 300 case AF_INET: 301 /* 302 * gre_transmit() has used M_PREPEND() that doesn't guarantee 303 * m_data is contiguous more than hlen bytes. Use m_copydata() 304 * here to avoid m_pullup(). 305 */ 306 m_copydata(m, hlen + offsetof(struct ip, ip_tos), 307 sizeof(u_char), &gi->gi_ip.ip_tos); 308 m_copydata(m, hlen + offsetof(struct ip, ip_id), 309 sizeof(u_short), (caddr_t)&gi->gi_ip.ip_id); 310 break; 311 #ifdef INET6 312 case AF_INET6: 313 gi->gi_ip.ip_tos = 0; /* XXX */ 314 ip_fillid(&gi->gi_ip); 315 break; 316 #endif 317 } 318 gi->gi_ip.ip_ttl = V_ip_gre_ttl; 319 gi->gi_ip.ip_len = htons(m->m_pkthdr.len); 320 return (ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL)); 321 } 322 323 static const struct srcaddrtab *ipv4_srcaddrtab = NULL; 324 static const struct encaptab *ecookie = NULL; 325 static const struct encap_config ipv4_encap_cfg = { 326 .proto = IPPROTO_GRE, 327 .min_length = sizeof(struct greip) + sizeof(struct ip), 328 .exact_match = ENCAP_DRV_LOOKUP, 329 .lookup = in_gre_lookup, 330 .input = gre_input 331 }; 332 333 void 334 in_gre_init(void) 335 { 336 337 if (!IS_DEFAULT_VNET(curvnet)) 338 return; 339 ipv4_srcaddrtab = ip_encap_register_srcaddr(in_gre_srcaddr, 340 NULL, M_WAITOK); 341 ecookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK); 342 } 343 344 void 345 in_gre_uninit(void) 346 { 347 348 if (IS_DEFAULT_VNET(curvnet)) { 349 ip_encap_detach(ecookie); 350 ip_encap_unregister_srcaddr(ipv4_srcaddrtab); 351 } 352 if (V_ipv4_hashtbl != NULL) { 353 gre_hashdestroy(V_ipv4_hashtbl); 354 V_ipv4_hashtbl = NULL; 355 GRE_WAIT(); 356 gre_hashdestroy(V_ipv4_srchashtbl); 357 } 358 } 359