1 /* $NetBSD: in_gif.c,v 1.63 2013/03/01 18:25:57 joerg Exp $ */ 2 /* $KAME: in_gif.c,v 1.66 2001/07/29 04:46:09 itojun Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 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 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: in_gif.c,v 1.63 2013/03/01 18:25:57 joerg Exp $"); 35 36 #include "opt_inet.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/socket.h> 41 #include <sys/sockio.h> 42 #include <sys/mbuf.h> 43 #include <sys/errno.h> 44 #include <sys/ioctl.h> 45 #include <sys/syslog.h> 46 #include <sys/protosw.h> 47 #include <sys/kernel.h> 48 49 #include <net/if.h> 50 #include <net/route.h> 51 52 #include <netinet/in.h> 53 #include <netinet/in_systm.h> 54 #include <netinet/ip.h> 55 #include <netinet/ip_var.h> 56 #include <netinet/in_gif.h> 57 #include <netinet/in_var.h> 58 #include <netinet/ip_encap.h> 59 #include <netinet/ip_ecn.h> 60 61 #ifdef INET6 62 #include <netinet/ip6.h> 63 #endif 64 65 #include <net/if_gif.h> 66 67 #include "gif.h" 68 69 #include <net/net_osdep.h> 70 71 static int gif_validate4(const struct ip *, struct gif_softc *, 72 struct ifnet *); 73 74 #if NGIF > 0 75 int ip_gif_ttl = GIF_TTL; 76 #else 77 int ip_gif_ttl = 0; 78 #endif 79 80 const struct protosw in_gif_protosw = 81 { SOCK_RAW, &inetdomain, 0/* IPPROTO_IPV[46] */, PR_ATOMIC|PR_ADDR, 82 in_gif_input, rip_output, 0, rip_ctloutput, 83 rip_usrreq, 84 0, 0, 0, 0, 85 }; 86 87 int 88 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m) 89 { 90 struct rtentry *rt; 91 struct gif_softc *sc = ifp->if_softc; 92 struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc; 93 struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst; 94 struct ip iphdr; /* capsule IP header, host byte ordered */ 95 int proto, error; 96 u_int8_t tos; 97 union { 98 struct sockaddr dst; 99 struct sockaddr_in dst4; 100 } u; 101 102 if (sin_src == NULL || sin_dst == NULL || 103 sin_src->sin_family != AF_INET || 104 sin_dst->sin_family != AF_INET) { 105 m_freem(m); 106 return EAFNOSUPPORT; 107 } 108 109 switch (family) { 110 #ifdef INET 111 case AF_INET: 112 { 113 const struct ip *ip; 114 115 proto = IPPROTO_IPV4; 116 if (m->m_len < sizeof(*ip)) { 117 m = m_pullup(m, sizeof(*ip)); 118 if (m == NULL) 119 return ENOBUFS; 120 } 121 ip = mtod(m, const struct ip *); 122 tos = ip->ip_tos; 123 break; 124 } 125 #endif /* INET */ 126 #ifdef INET6 127 case AF_INET6: 128 { 129 const struct ip6_hdr *ip6; 130 proto = IPPROTO_IPV6; 131 if (m->m_len < sizeof(*ip6)) { 132 m = m_pullup(m, sizeof(*ip6)); 133 if (m == NULL) 134 return ENOBUFS; 135 } 136 ip6 = mtod(m, const struct ip6_hdr *); 137 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 138 break; 139 } 140 #endif /* INET6 */ 141 default: 142 #ifdef DEBUG 143 printf("in_gif_output: warning: unknown family %d passed\n", 144 family); 145 #endif 146 m_freem(m); 147 return EAFNOSUPPORT; 148 } 149 150 memset(&iphdr, 0, sizeof(iphdr)); 151 iphdr.ip_src = sin_src->sin_addr; 152 /* bidirectional configured tunnel mode */ 153 if (sin_dst->sin_addr.s_addr != INADDR_ANY) 154 iphdr.ip_dst = sin_dst->sin_addr; 155 else { 156 m_freem(m); 157 return ENETUNREACH; 158 } 159 iphdr.ip_p = proto; 160 /* version will be set in ip_output() */ 161 iphdr.ip_ttl = ip_gif_ttl; 162 iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip)); 163 if (ifp->if_flags & IFF_LINK1) 164 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos); 165 else 166 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos); 167 168 /* prepend new IP header */ 169 M_PREPEND(m, sizeof(struct ip), M_DONTWAIT); 170 /* XXX Is m_pullup really necessary after M_PREPEND? */ 171 if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip))) 172 m = m_pullup(m, sizeof(struct ip)); 173 if (m == NULL) 174 return ENOBUFS; 175 bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip)); 176 177 sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0); 178 if ((rt = rtcache_lookup(&sc->gif_ro, &u.dst)) == NULL) { 179 m_freem(m); 180 return ENETUNREACH; 181 } 182 183 /* If the route constitutes infinite encapsulation, punt. */ 184 if (rt->rt_ifp == ifp) { 185 rtcache_free(&sc->gif_ro); 186 m_freem(m); 187 return ENETUNREACH; /*XXX*/ 188 } 189 190 error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL); 191 return (error); 192 } 193 194 void 195 in_gif_input(struct mbuf *m, ...) 196 { 197 int off, proto; 198 struct ifnet *gifp = NULL; 199 const struct ip *ip; 200 va_list ap; 201 int af; 202 u_int8_t otos; 203 204 va_start(ap, m); 205 off = va_arg(ap, int); 206 proto = va_arg(ap, int); 207 va_end(ap); 208 209 ip = mtod(m, const struct ip *); 210 211 gifp = (struct ifnet *)encap_getarg(m); 212 213 if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) { 214 m_freem(m); 215 ip_statinc(IP_STAT_NOGIF); 216 return; 217 } 218 #ifndef GIF_ENCAPCHECK 219 if (!gif_validate4(ip, gifp->if_softc, m->m_pkthdr.rcvif)) { 220 m_freem(m); 221 ip_statinc(IP_STAT_NOGIF); 222 return; 223 } 224 #endif 225 226 otos = ip->ip_tos; 227 m_adj(m, off); 228 229 switch (proto) { 230 #ifdef INET 231 case IPPROTO_IPV4: 232 { 233 struct ip *xip; 234 af = AF_INET; 235 if (M_UNWRITABLE(m, sizeof(*xip))) { 236 if ((m = m_pullup(m, sizeof(*xip))) == NULL) 237 return; 238 } 239 xip = mtod(m, struct ip *); 240 if (gifp->if_flags & IFF_LINK1) 241 ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos); 242 else 243 ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos); 244 break; 245 } 246 #endif 247 #ifdef INET6 248 case IPPROTO_IPV6: 249 { 250 struct ip6_hdr *ip6; 251 u_int8_t itos; 252 af = AF_INET6; 253 if (M_UNWRITABLE(m, sizeof(*ip6))) { 254 if ((m = m_pullup(m, sizeof(*ip6))) == NULL) 255 return; 256 } 257 ip6 = mtod(m, struct ip6_hdr *); 258 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 259 if (gifp->if_flags & IFF_LINK1) 260 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 261 else 262 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 263 ip6->ip6_flow &= ~htonl(0xff << 20); 264 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 265 break; 266 } 267 #endif /* INET6 */ 268 default: 269 ip_statinc(IP_STAT_NOGIF); 270 m_freem(m); 271 return; 272 } 273 gif_input(m, af, gifp); 274 return; 275 } 276 277 /* 278 * validate outer address. 279 */ 280 static int 281 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp) 282 { 283 struct sockaddr_in *src, *dst; 284 struct in_ifaddr *ia4; 285 286 src = (struct sockaddr_in *)sc->gif_psrc; 287 dst = (struct sockaddr_in *)sc->gif_pdst; 288 289 /* check for address match */ 290 if (src->sin_addr.s_addr != ip->ip_dst.s_addr || 291 dst->sin_addr.s_addr != ip->ip_src.s_addr) 292 return 0; 293 294 /* martian filters on outer source - NOT done in ip_input! */ 295 if (IN_MULTICAST(ip->ip_src.s_addr)) 296 return 0; 297 switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) { 298 case 0: case 127: case 255: 299 return 0; 300 } 301 /* reject packets with broadcast on source */ 302 TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) { 303 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 304 continue; 305 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) 306 return 0; 307 } 308 309 /* ingress filters on outer source */ 310 if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) { 311 union { 312 struct sockaddr sa; 313 struct sockaddr_in sin; 314 } u; 315 struct rtentry *rt; 316 317 sockaddr_in_init(&u.sin, &ip->ip_src, 0); 318 rt = rtalloc1(&u.sa, 0); 319 if (rt == NULL || rt->rt_ifp != ifp) { 320 #if 0 321 log(LOG_WARNING, "%s: packet from 0x%x dropped " 322 "due to ingress filter\n", if_name(&sc->gif_if), 323 (u_int32_t)ntohl(u.sin.sin_addr.s_addr)); 324 #endif 325 if (rt != NULL) 326 rtfree(rt); 327 return 0; 328 } 329 rtfree(rt); 330 } 331 332 return 32 * 2; 333 } 334 335 #ifdef GIF_ENCAPCHECK 336 /* 337 * we know that we are in IFF_UP, outer address available, and outer family 338 * matched the physical addr family. see gif_encapcheck(). 339 */ 340 int 341 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg) 342 { 343 struct ip ip; 344 struct gif_softc *sc; 345 struct ifnet *ifp; 346 347 /* sanity check done in caller */ 348 sc = arg; 349 350 m_copydata(m, 0, sizeof(ip), &ip); 351 ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL; 352 353 return gif_validate4(&ip, sc, ifp); 354 } 355 #endif 356 357 int 358 in_gif_attach(struct gif_softc *sc) 359 { 360 #ifndef GIF_ENCAPCHECK 361 struct sockaddr_in mask4; 362 363 memset(&mask4, 0, sizeof(mask4)); 364 mask4.sin_len = sizeof(struct sockaddr_in); 365 mask4.sin_addr.s_addr = ~0; 366 367 if (!sc->gif_psrc || !sc->gif_pdst) 368 return EINVAL; 369 sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc, 370 (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4, 371 (const struct protosw *)&in_gif_protosw, sc); 372 #else 373 sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck, 374 &in_gif_protosw, sc); 375 #endif 376 if (sc->encap_cookie4 == NULL) 377 return EEXIST; 378 return 0; 379 } 380 381 int 382 in_gif_detach(struct gif_softc *sc) 383 { 384 int error; 385 386 error = encap_detach(sc->encap_cookie4); 387 if (error == 0) 388 sc->encap_cookie4 = NULL; 389 390 rtcache_free(&sc->gif_ro); 391 392 return error; 393 } 394