ip6_forward.c revision 1.1.2.2
1 /* 2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the project nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if (defined(__FreeBSD__) && __FreeBSD__ >= 3) 31 #include "opt_ip6fw.h" 32 #include "opt_inet.h" 33 #endif 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/malloc.h> 38 #include <sys/mbuf.h> 39 #include <sys/domain.h> 40 #include <sys/protosw.h> 41 #include <sys/socket.h> 42 #include <sys/errno.h> 43 #include <sys/time.h> 44 #include <sys/kernel.h> 45 #include <sys/syslog.h> 46 47 #include <net/if.h> 48 #include <net/route.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_var.h> 52 #include <netinet6/ip6.h> 53 #include <netinet6/ip6_var.h> 54 #include <netinet6/icmp6.h> 55 #include <netinet6/nd6.h> 56 57 #ifdef __OpenBSD__ /*KAME IPSEC*/ 58 #undef IPSEC 59 #endif 60 61 #ifdef IPSEC_IPV6FWD 62 #include <netinet6/ipsec.h> 63 #include <netkey/key.h> 64 #include <netkey/key_debug.h> 65 #endif /* IPSEC_IPV6FWD */ 66 67 #ifdef IPV6FIREWALL 68 #include <netinet6/ip6_fw.h> 69 #endif 70 71 #include <net/net_osdep.h> 72 73 struct route_in6 ip6_forward_rt; 74 75 /* 76 * Forward a packet. If some error occurs return the sender 77 * an icmp packet. Note we can't always generate a meaningful 78 * icmp message because icmp doesn't have a large enough repertoire 79 * of codes and types. 80 * 81 * If not forwarding, just drop the packet. This could be confusing 82 * if ipforwarding was zero but some routing protocol was advancing 83 * us as a gateway to somewhere. However, we must let the routing 84 * protocol deal with that. 85 * 86 */ 87 88 void 89 ip6_forward(m, srcrt) 90 struct mbuf *m; 91 int srcrt; 92 { 93 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 94 register struct sockaddr_in6 *dst; 95 register struct rtentry *rt; 96 int error, type = 0, code = 0; 97 struct mbuf *mcopy; 98 #ifdef IPSEC_IPV6FWD 99 struct secpolicy *sp = NULL; 100 #endif 101 #if !(defined(__FreeBSD__) && __FreeBSD__ >= 3) 102 long time_second = time.tv_sec; 103 #endif 104 105 #ifdef IPSEC_IPV6FWD 106 /* 107 * Check AH/ESP integrity. 108 */ 109 /* 110 * Don't increment ip6s_cantforward because this is the check 111 * before forwarding packet actually. 112 */ 113 if (ipsec6_in_reject(m, NULL)) { 114 ipsec6stat.in_polvio++; 115 m_freem(m); 116 return; 117 } 118 #endif /*IPSEC_IPV6FWD*/ 119 120 if (m->m_flags & (M_BCAST|M_MCAST) || 121 in6_canforward(&ip6->ip6_src, &ip6->ip6_dst) == 0) { 122 ip6stat.ip6s_cantforward++; 123 ip6stat.ip6s_badscope++; 124 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 125 if (ip6_log_time + ip6_log_interval < time_second) { 126 char addr[INET6_ADDRSTRLEN]; 127 ip6_log_time = time_second; 128 strncpy(addr, ip6_sprintf(&ip6->ip6_src), sizeof(addr)); 129 log(LOG_DEBUG, 130 "cannot forward " 131 "from %s to %s nxt %d received on %s\n", 132 addr, ip6_sprintf(&ip6->ip6_dst), 133 ip6->ip6_nxt, 134 if_name(m->m_pkthdr.rcvif)); 135 } 136 m_freem(m); 137 return; 138 } 139 140 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 141 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 142 icmp6_error(m, ICMP6_TIME_EXCEEDED, 143 ICMP6_TIME_EXCEED_TRANSIT, 0); 144 return; 145 } 146 ip6->ip6_hlim -= IPV6_HLIMDEC; 147 148 #ifdef IPSEC_IPV6FWD 149 /* get a security policy for this packet */ 150 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error); 151 if (sp == NULL) { 152 ipsec6stat.out_inval++; 153 ip6stat.ip6s_cantforward++; 154 #if 0 155 /* XXX: what icmp ? */ 156 #else 157 m_freem(m); 158 #endif 159 return; 160 } 161 162 error = 0; 163 164 /* check policy */ 165 switch (sp->policy) { 166 case IPSEC_POLICY_DISCARD: 167 /* 168 * This packet is just discarded. 169 */ 170 ipsec6stat.out_polvio++; 171 ip6stat.ip6s_cantforward++; 172 key_freesp(sp); 173 #if 0 174 /* XXX: what icmp ? */ 175 #else 176 m_freem(m); 177 #endif 178 return; 179 180 case IPSEC_POLICY_BYPASS: 181 case IPSEC_POLICY_NONE: 182 /* no need to do IPsec. */ 183 key_freesp(sp); 184 goto skip_ipsec; 185 186 case IPSEC_POLICY_IPSEC: 187 if (sp->req == NULL) { 188 /* XXX should be panic ? */ 189 printf("ip6_forward: No IPsec request specified.\n"); 190 ip6stat.ip6s_cantforward++; 191 key_freesp(sp); 192 #if 0 193 /* XXX: what icmp ? */ 194 #else 195 m_freem(m); 196 #endif 197 return; 198 } 199 /* do IPsec */ 200 break; 201 202 case IPSEC_POLICY_ENTRUST: 203 default: 204 /* should be panic ?? */ 205 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 206 key_freesp(sp); 207 goto skip_ipsec; 208 } 209 210 { 211 struct ipsec_output_state state; 212 213 /* 214 * All the extension headers will become inaccessible 215 * (since they can be encrypted). 216 * Don't panic, we need no more updates to extension headers 217 * on inner IPv6 packet (since they are now encapsulated). 218 * 219 * IPv6 [ESP|AH] IPv6 [extension headers] payload 220 */ 221 bzero(&state, sizeof(state)); 222 state.m = m; 223 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 224 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 225 226 error = ipsec6_output_tunnel(&state, sp, 0); 227 228 m = state.m; 229 #if 0 /* XXX allocate a route (ro, dst) again later */ 230 ro = (struct route_in6 *)state.ro; 231 dst = (struct sockaddr_in6 *)state.dst; 232 #endif 233 key_freesp(sp); 234 235 if (error) { 236 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 237 switch (error) { 238 case EHOSTUNREACH: 239 case ENETUNREACH: 240 case EMSGSIZE: 241 case ENOBUFS: 242 case ENOMEM: 243 break; 244 default: 245 printf("ip6_output (ipsec): error code %d\n", error); 246 /*fall through*/ 247 case ENOENT: 248 /* don't show these error codes to the user */ 249 break; 250 } 251 ip6stat.ip6s_cantforward++; 252 #if 0 253 /* XXX: what icmp ? */ 254 #else 255 m_freem(m); 256 #endif 257 return; 258 } 259 } 260 skip_ipsec: 261 #endif /* IPSEC_IPV6FWD */ 262 263 dst = &ip6_forward_rt.ro_dst; 264 if (!srcrt) { 265 /* 266 * ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst 267 */ 268 if (ip6_forward_rt.ro_rt == 0 || 269 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 270 if (ip6_forward_rt.ro_rt) { 271 RTFREE(ip6_forward_rt.ro_rt); 272 ip6_forward_rt.ro_rt = 0; 273 } 274 /* this probably fails but give it a try again */ 275 #ifdef __FreeBSD__ 276 rtalloc_ign((struct route *)&ip6_forward_rt, 277 RTF_PRCLONING); 278 #else 279 rtalloc((struct route *)&ip6_forward_rt); 280 #endif 281 } 282 283 if (ip6_forward_rt.ro_rt == 0) { 284 ip6stat.ip6s_noroute++; 285 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 286 icmp6_error(m, ICMP6_DST_UNREACH, 287 ICMP6_DST_UNREACH_NOROUTE, 0); 288 return; 289 } 290 } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 291 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 292 if (ip6_forward_rt.ro_rt) { 293 RTFREE(ip6_forward_rt.ro_rt); 294 ip6_forward_rt.ro_rt = 0; 295 } 296 bzero(dst, sizeof(*dst)); 297 dst->sin6_len = sizeof(struct sockaddr_in6); 298 dst->sin6_family = AF_INET6; 299 dst->sin6_addr = ip6->ip6_dst; 300 301 #ifdef __FreeBSD__ 302 rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); 303 #else 304 rtalloc((struct route *)&ip6_forward_rt); 305 #endif 306 if (ip6_forward_rt.ro_rt == 0) { 307 ip6stat.ip6s_noroute++; 308 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 309 icmp6_error(m, ICMP6_DST_UNREACH, 310 ICMP6_DST_UNREACH_NOROUTE, 0); 311 return; 312 } 313 } 314 rt = ip6_forward_rt.ro_rt; 315 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu){ 316 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 317 icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, rt->rt_ifp->if_mtu); 318 return; 319 } 320 321 if (rt->rt_flags & RTF_GATEWAY) 322 dst = (struct sockaddr_in6 *)rt->rt_gateway; 323 /* 324 * Save at most 528 bytes of the packet in case 325 * we need to generate an ICMP6 message to the src. 326 * Thanks to M_EXT, in most cases copy will not occur. 327 */ 328 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 329 330 /* 331 * If we are to forward the packet using the same interface 332 * as one we got the packet from, perhaps we should send a redirect 333 * to sender to shortcut a hop. 334 * Only send redirect if source is sending directly to us, 335 * and if packet was not source routed (or has any options). 336 * Also, don't send redirect if forwarding using a route 337 * modified by a redirect. 338 */ 339 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 340 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) 341 type = ND_REDIRECT; 342 343 #ifdef IPV6FIREWALL 344 /* 345 * Check with the firewall... 346 */ 347 if (ip6_fw_chk_ptr) { 348 u_short port = 0; 349 /* If ipfw says divert, we have to just drop packet */ 350 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 351 m_freem(m); 352 goto freecopy; 353 } 354 if (!m) 355 goto freecopy; 356 } 357 #endif 358 359 #ifdef OLDIP6OUTPUT 360 error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, 361 (struct sockaddr *)dst, 362 ip6_forward_rt.ro_rt); 363 #else 364 error = nd6_output(rt->rt_ifp, m, dst, rt); 365 #endif 366 if (error) { 367 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 368 ip6stat.ip6s_cantforward++; 369 } else { 370 ip6stat.ip6s_forward++; 371 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 372 if (type) 373 ip6stat.ip6s_redirectsent++; 374 else { 375 if (mcopy) 376 goto freecopy; 377 } 378 } 379 if (mcopy == NULL) 380 return; 381 382 switch (error) { 383 case 0: 384 #if 1 385 if (type == ND_REDIRECT) { 386 icmp6_redirect_output(mcopy, rt); 387 return; 388 } 389 #endif 390 goto freecopy; 391 392 case EMSGSIZE: 393 /* xxx MTU is constant in PPP? */ 394 goto freecopy; 395 396 case ENOBUFS: 397 /* Tell source to slow down like source quench in IP? */ 398 goto freecopy; 399 400 case ENETUNREACH: /* shouldn't happen, checked above */ 401 case EHOSTUNREACH: 402 case ENETDOWN: 403 case EHOSTDOWN: 404 default: 405 type = ICMP6_DST_UNREACH; 406 code = ICMP6_DST_UNREACH_ADDR; 407 break; 408 } 409 icmp6_error(mcopy, type, code, 0); 410 return; 411 412 freecopy: 413 m_freem(mcopy); 414 return; 415 } 416
Indexes created Wed Oct 15 03:09:54 GMT 2025