1 /* $NetBSD: in_gif.c,v 1.75 2016/01/26 06:00:10 knakahara 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 1.75 2016/01/26 06:00:10 knakahara Exp $"); 35 36 #ifdef _KERNEL_OPT 37 #include "opt_inet.h" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/socket.h> 43 #include <sys/sockio.h> 44 #include <sys/mbuf.h> 45 #include <sys/errno.h> 46 #include <sys/ioctl.h> 47 #include <sys/syslog.h> 48 #include <sys/kernel.h> 49 50 #include <net/if.h> 51 #include <net/route.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_var.h> 57 #include <netinet/in_gif.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_encap.h> 60 #include <netinet/ip_ecn.h> 61 62 #ifdef INET6 63 #include <netinet/ip6.h> 64 #endif 65 66 #include <net/if_gif.h> 67 68 #include "gif.h" 69 70 #include <net/net_osdep.h> 71 72 static int gif_validate4(const struct ip *, struct gif_softc *, 73 struct ifnet *); 74 75 #if NGIF > 0 76 int ip_gif_ttl = GIF_TTL; 77 #else 78 int ip_gif_ttl = 0; 79 #endif 80 81 static const struct encapsw in_gif_encapsw = { 82 .encapsw4 = { 83 .pr_input = in_gif_input, 84 .pr_ctlinput = NULL, 85 } 86 }; 87 88 int 89 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m) 90 { 91 struct rtentry *rt; 92 struct gif_softc *sc = ifp->if_softc; 93 struct sockaddr_in *sin_src = satosin(sc->gif_psrc); 94 struct sockaddr_in *sin_dst = satosin(sc->gif_pdst); 95 struct ip iphdr; /* capsule IP header, host byte ordered */ 96 int proto, error; 97 u_int8_t tos; 98 union { 99 struct sockaddr dst; 100 struct sockaddr_in dst4; 101 } u; 102 103 if (sin_src == NULL || sin_dst == NULL || 104 sin_src->sin_family != AF_INET || 105 sin_dst->sin_family != AF_INET) { 106 m_freem(m); 107 return EAFNOSUPPORT; 108 } 109 110 switch (family) { 111 #ifdef INET 112 case AF_INET: 113 { 114 const struct ip *ip; 115 116 proto = IPPROTO_IPV4; 117 if (m->m_len < sizeof(*ip)) { 118 m = m_pullup(m, sizeof(*ip)); 119 if (m == NULL) 120 return ENOBUFS; 121 } 122 ip = mtod(m, const struct ip *); 123 tos = ip->ip_tos; 124 break; 125 } 126 #endif /* INET */ 127 #ifdef INET6 128 case AF_INET6: 129 { 130 const struct ip6_hdr *ip6; 131 proto = IPPROTO_IPV6; 132 if (m->m_len < sizeof(*ip6)) { 133 m = m_pullup(m, sizeof(*ip6)); 134 if (m == NULL) 135 return ENOBUFS; 136 } 137 ip6 = mtod(m, const struct ip6_hdr *); 138 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 139 break; 140 } 141 #endif /* INET6 */ 142 default: 143 #ifdef DEBUG 144 printf("in_gif_output: warning: unknown family %d passed\n", 145 family); 146 #endif 147 m_freem(m); 148 return EAFNOSUPPORT; 149 } 150 151 memset(&iphdr, 0, sizeof(iphdr)); 152 iphdr.ip_src = sin_src->sin_addr; 153 /* bidirectional configured tunnel mode */ 154 if (sin_dst->sin_addr.s_addr != INADDR_ANY) 155 iphdr.ip_dst = sin_dst->sin_addr; 156 else { 157 m_freem(m); 158 return ENETUNREACH; 159 } 160 iphdr.ip_p = proto; 161 /* version will be set in ip_output() */ 162 iphdr.ip_ttl = ip_gif_ttl; 163 iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip)); 164 if (ifp->if_flags & IFF_LINK1) 165 ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos); 166 else 167 ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos); 168 169 /* prepend new IP header */ 170 M_PREPEND(m, sizeof(struct ip), M_DONTWAIT); 171 /* XXX Is m_pullup really necessary after M_PREPEND? */ 172 if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip))) 173 m = m_pullup(m, sizeof(struct ip)); 174 if (m == NULL) 175 return ENOBUFS; 176 bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip)); 177 178 sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0); 179 if ((rt = rtcache_lookup(&sc->gif_ro, &u.dst)) == NULL) { 180 m_freem(m); 181 return ENETUNREACH; 182 } 183 184 /* If the route constitutes infinite encapsulation, punt. */ 185 if (rt->rt_ifp == ifp) { 186 rtcache_free(&sc->gif_ro); 187 m_freem(m); 188 return ENETUNREACH; /*XXX*/ 189 } 190 191 error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL); 192 return (error); 193 } 194 195 void 196 in_gif_input(struct mbuf *m, int off, int proto) 197 { 198 struct ifnet *gifp = NULL; 199 const struct ip *ip; 200 int af; 201 u_int8_t otos; 202 203 ip = mtod(m, const struct ip *); 204 205 gifp = (struct ifnet *)encap_getarg(m); 206 207 if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) { 208 m_freem(m); 209 ip_statinc(IP_STAT_NOGIF); 210 return; 211 } 212 #ifndef GIF_ENCAPCHECK 213 struct gif_softc *sc = (struct gif_softc *)gifp->if_softc; 214 /* other CPU do delete_tunnel */ 215 if (sc->gif_psrc == NULL || sc->gif_pdst == NULL) { 216 m_freem(m); 217 ip_statinc(IP_STAT_NOGIF); 218 return; 219 } 220 221 if (!gif_validate4(ip, sc, m->m_pkthdr.rcvif)) { 222 m_freem(m); 223 ip_statinc(IP_STAT_NOGIF); 224 return; 225 } 226 #endif 227 otos = ip->ip_tos; 228 m_adj(m, off); 229 230 switch (proto) { 231 #ifdef INET 232 case IPPROTO_IPV4: 233 { 234 struct ip *xip; 235 af = AF_INET; 236 if (M_UNWRITABLE(m, sizeof(*xip))) { 237 if ((m = m_pullup(m, sizeof(*xip))) == NULL) 238 return; 239 } 240 xip = mtod(m, struct ip *); 241 if (gifp->if_flags & IFF_LINK1) 242 ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos); 243 else 244 ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos); 245 break; 246 } 247 #endif 248 #ifdef INET6 249 case IPPROTO_IPV6: 250 { 251 struct ip6_hdr *ip6; 252 u_int8_t itos; 253 af = AF_INET6; 254 if (M_UNWRITABLE(m, sizeof(*ip6))) { 255 if ((m = m_pullup(m, sizeof(*ip6))) == NULL) 256 return; 257 } 258 ip6 = mtod(m, struct ip6_hdr *); 259 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 260 if (gifp->if_flags & IFF_LINK1) 261 ip_ecn_egress(ECN_ALLOWED, &otos, &itos); 262 else 263 ip_ecn_egress(ECN_NOCARE, &otos, &itos); 264 ip6->ip6_flow &= ~htonl(0xff << 20); 265 ip6->ip6_flow |= htonl((u_int32_t)itos << 20); 266 break; 267 } 268 #endif /* INET6 */ 269 default: 270 ip_statinc(IP_STAT_NOGIF); 271 m_freem(m); 272 return; 273 } 274 gif_input(m, af, gifp); 275 return; 276 } 277 278 /* 279 * validate outer address. 280 */ 281 static int 282 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp) 283 { 284 struct sockaddr_in *src, *dst; 285 struct in_ifaddr *ia4; 286 287 src = satosin(sc->gif_psrc); 288 dst = satosin(sc->gif_pdst); 289 290 /* check for address match */ 291 if (src->sin_addr.s_addr != ip->ip_dst.s_addr || 292 dst->sin_addr.s_addr != ip->ip_src.s_addr) 293 return 0; 294 295 /* martian filters on outer source - NOT done in ip_input! */ 296 if (IN_MULTICAST(ip->ip_src.s_addr)) 297 return 0; 298 switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) { 299 case 0: case 127: case 255: 300 return 0; 301 } 302 /* reject packets with broadcast on source */ 303 TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) { 304 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0) 305 continue; 306 if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) 307 return 0; 308 } 309 310 /* ingress filters on outer source */ 311 if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) { 312 union { 313 struct sockaddr sa; 314 struct sockaddr_in sin; 315 } u; 316 struct rtentry *rt; 317 318 sockaddr_in_init(&u.sin, &ip->ip_src, 0); 319 rt = rtalloc1(&u.sa, 0); 320 if (rt == NULL || rt->rt_ifp != ifp) { 321 #if 0 322 log(LOG_WARNING, "%s: packet from 0x%x dropped " 323 "due to ingress filter\n", if_name(&sc->gif_if), 324 (u_int32_t)ntohl(u.sin.sin_addr.s_addr)); 325 #endif 326 if (rt != NULL) 327 rtfree(rt); 328 return 0; 329 } 330 rtfree(rt); 331 } 332 333 return 32 * 2; 334 } 335 336 #ifdef GIF_ENCAPCHECK 337 /* 338 * we know that we are in IFF_UP, outer address available, and outer family 339 * matched the physical addr family. see gif_encapcheck(). 340 */ 341 int 342 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg) 343 { 344 struct ip ip; 345 struct gif_softc *sc; 346 struct ifnet *ifp; 347 348 /* sanity check done in caller */ 349 sc = arg; 350 351 m_copydata(m, 0, sizeof(ip), &ip); 352 ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL; 353 354 return gif_validate4(&ip, sc, ifp); 355 } 356 #endif 357 358 int 359 in_gif_attach(struct gif_softc *sc) 360 { 361 #ifndef GIF_ENCAPCHECK 362 struct sockaddr_in mask4; 363 364 memset(&mask4, 0, sizeof(mask4)); 365 mask4.sin_len = sizeof(struct sockaddr_in); 366 mask4.sin_addr.s_addr = ~0; 367 368 if (!sc->gif_psrc || !sc->gif_pdst) 369 return EINVAL; 370 sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc, 371 (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4, 372 &in_gif_encapsw, sc); 373 #else 374 sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck, 375 &in_gif_encapsw, sc); 376 #endif 377 if (sc->encap_cookie4 == NULL) 378 return EEXIST; 379 return 0; 380 } 381 382 int 383 in_gif_detach(struct gif_softc *sc) 384 { 385 int error; 386 387 error = encap_detach(sc->encap_cookie4); 388 if (error == 0) 389 sc->encap_cookie4 = NULL; 390 391 rtcache_free(&sc->gif_ro); 392 393 return error; 394 } 395