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 * $FreeBSD$ 30 */ 31 32 #include "opt_ipsec.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/malloc.h> 37 #include <sys/mbuf.h> 38 #include <sys/domain.h> 39 #include <sys/protosw.h> 40 #include <sys/socket.h> 41 #include <sys/errno.h> 42 #include <sys/time.h> 43 #include <sys/kernel.h> 44 #include <sys/syslog.h> 45 46 #include <net/if.h> 47 #include <net/route.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_var.h> 51 #include <netinet6/ip6.h> 52 #include <netinet6/ip6_var.h> 53 #include <netinet6/icmp6.h> 54 #include <netinet6/nd6.h> 55 56 #ifdef IPSEC_IPV6FWD 57 #include <netinet6/ipsec.h> 58 #include <netinet6/ipsec6.h> 59 #include <netkey/key.h> 60 #ifdef IPSEC_DEBUG 61 #include <netkey/key_debug.h> 62 #else 63 #define KEYDEBUG(lev,arg) 64 #endif 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 101 102 #ifdef IPSEC_IPV6FWD 103 /* 104 * Check AH/ESP integrity. 105 */ 106 /* 107 * Don't increment ip6s_cantforward because this is the check 108 * before forwarding packet actually. 109 */ 110 if (ipsec6_in_reject(m, NULL)) { 111 ipsec6stat.in_polvio++; 112 m_freem(m); 113 return; 114 } 115 #endif /*IPSEC_IPV6FWD*/ 116 117 if (m->m_flags & (M_BCAST|M_MCAST) || 118 in6_canforward(&ip6->ip6_src, &ip6->ip6_dst) == 0) { 119 ip6stat.ip6s_cantforward++; 120 ip6stat.ip6s_badscope++; 121 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 122 if (ip6_log_time + ip6_log_interval < time_second) { 123 char addr[INET6_ADDRSTRLEN]; 124 ip6_log_time = time_second; 125 strncpy(addr, ip6_sprintf(&ip6->ip6_src), sizeof(addr)); 126 log(LOG_DEBUG, 127 "cannot forward " 128 "from %s to %s nxt %d received on %s\n", 129 addr, ip6_sprintf(&ip6->ip6_dst), 130 ip6->ip6_nxt, 131 if_name(m->m_pkthdr.rcvif)); 132 } 133 m_freem(m); 134 return; 135 } 136 137 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 138 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 139 icmp6_error(m, ICMP6_TIME_EXCEEDED, 140 ICMP6_TIME_EXCEED_TRANSIT, 0); 141 return; 142 } 143 ip6->ip6_hlim -= IPV6_HLIMDEC; 144 145 #ifdef IPSEC_IPV6FWD 146 /* get a security policy for this packet */ 147 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 0, &error); 148 if (sp == NULL) { 149 ipsec6stat.out_inval++; 150 ip6stat.ip6s_cantforward++; 151 /* XXX: any icmp ? */ 152 m_freem(m); 153 return; 154 } 155 156 error = 0; 157 158 /* check policy */ 159 switch (sp->policy) { 160 case IPSEC_POLICY_DISCARD: 161 /* 162 * This packet is just discarded. 163 */ 164 ipsec6stat.out_polvio++; 165 ip6stat.ip6s_cantforward++; 166 key_freesp(sp); 167 /* XXX: any icmp ? */ 168 m_freem(m); 169 return; 170 171 case IPSEC_POLICY_BYPASS: 172 case IPSEC_POLICY_NONE: 173 /* no need to do IPsec. */ 174 key_freesp(sp); 175 goto skip_ipsec; 176 177 case IPSEC_POLICY_IPSEC: 178 if (sp->req == NULL) { 179 /* XXX should be panic ? */ 180 printf("ip6_forward: No IPsec request specified.\n"); 181 ip6stat.ip6s_cantforward++; 182 key_freesp(sp); 183 /* XXX: any icmp ? */ 184 m_freem(m); 185 return; 186 } 187 /* do IPsec */ 188 break; 189 190 case IPSEC_POLICY_ENTRUST: 191 default: 192 /* should be panic ?? */ 193 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 194 key_freesp(sp); 195 goto skip_ipsec; 196 } 197 198 { 199 struct ipsec_output_state state; 200 201 /* 202 * All the extension headers will become inaccessible 203 * (since they can be encrypted). 204 * Don't panic, we need no more updates to extension headers 205 * on inner IPv6 packet (since they are now encapsulated). 206 * 207 * IPv6 [ESP|AH] IPv6 [extension headers] payload 208 */ 209 bzero(&state, sizeof(state)); 210 state.m = m; 211 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 212 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 213 214 error = ipsec6_output_tunnel(&state, sp, 0); 215 216 m = state.m; 217 /* XXX allocate a route (ro, dst) again later */ 218 key_freesp(sp); 219 220 if (error) { 221 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 222 switch (error) { 223 case EHOSTUNREACH: 224 case ENETUNREACH: 225 case EMSGSIZE: 226 case ENOBUFS: 227 case ENOMEM: 228 break; 229 default: 230 printf("ip6_output (ipsec): error code %d\n", error); 231 /*fall through*/ 232 case ENOENT: 233 /* don't show these error codes to the user */ 234 break; 235 } 236 ip6stat.ip6s_cantforward++; 237 /* XXX: any icmp ? */ 238 m_freem(m); 239 return; 240 } 241 } 242 skip_ipsec: 243 #endif /* IPSEC_IPV6FWD */ 244 245 dst = &ip6_forward_rt.ro_dst; 246 if (!srcrt) { 247 /* 248 * ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst 249 */ 250 if (ip6_forward_rt.ro_rt == 0 || 251 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 252 if (ip6_forward_rt.ro_rt) { 253 RTFREE(ip6_forward_rt.ro_rt); 254 ip6_forward_rt.ro_rt = 0; 255 } 256 /* this probably fails but give it a try again */ 257 rtalloc_ign((struct route *)&ip6_forward_rt, 258 RTF_PRCLONING); 259 } 260 261 if (ip6_forward_rt.ro_rt == 0) { 262 ip6stat.ip6s_noroute++; 263 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 264 icmp6_error(m, ICMP6_DST_UNREACH, 265 ICMP6_DST_UNREACH_NOROUTE, 0); 266 return; 267 } 268 } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 269 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 270 if (ip6_forward_rt.ro_rt) { 271 RTFREE(ip6_forward_rt.ro_rt); 272 ip6_forward_rt.ro_rt = 0; 273 } 274 bzero(dst, sizeof(*dst)); 275 dst->sin6_len = sizeof(struct sockaddr_in6); 276 dst->sin6_family = AF_INET6; 277 dst->sin6_addr = ip6->ip6_dst; 278 279 rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); 280 if (ip6_forward_rt.ro_rt == 0) { 281 ip6stat.ip6s_noroute++; 282 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 283 icmp6_error(m, ICMP6_DST_UNREACH, 284 ICMP6_DST_UNREACH_NOROUTE, 0); 285 return; 286 } 287 } 288 rt = ip6_forward_rt.ro_rt; 289 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu){ 290 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 291 icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, rt->rt_ifp->if_mtu); 292 return; 293 } 294 295 if (rt->rt_flags & RTF_GATEWAY) 296 dst = (struct sockaddr_in6 *)rt->rt_gateway; 297 /* 298 * Save at most 528 bytes of the packet in case 299 * we need to generate an ICMP6 message to the src. 300 * Thanks to M_EXT, in most cases copy will not occur. 301 */ 302 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 303 304 /* 305 * If we are to forward the packet using the same interface 306 * as one we got the packet from, perhaps we should send a redirect 307 * to sender to shortcut a hop. 308 * Only send redirect if source is sending directly to us, 309 * and if packet was not source routed (or has any options). 310 * Also, don't send redirect if forwarding using a route 311 * modified by a redirect. 312 */ 313 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 314 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) 315 type = ND_REDIRECT; 316 317 #ifdef IPV6FIREWALL 318 /* 319 * Check with the firewall... 320 */ 321 if (ip6_fw_chk_ptr) { 322 u_short port = 0; 323 /* If ipfw says divert, we have to just drop packet */ 324 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 325 m_freem(m); 326 goto freecopy; 327 } 328 if (!m) 329 goto freecopy; 330 } 331 #endif 332 333 error = nd6_output(rt->rt_ifp, m, dst, rt); 334 if (error) { 335 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 336 ip6stat.ip6s_cantforward++; 337 } else { 338 ip6stat.ip6s_forward++; 339 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 340 if (type) 341 ip6stat.ip6s_redirectsent++; 342 else { 343 if (mcopy) 344 goto freecopy; 345 } 346 } 347 if (mcopy == NULL) 348 return; 349 350 switch (error) { 351 case 0: 352 if (type == ND_REDIRECT) { 353 icmp6_redirect_output(mcopy, rt); 354 return; 355 } 356 goto freecopy; 357 358 case EMSGSIZE: 359 /* xxx MTU is constant in PPP? */ 360 goto freecopy; 361 362 case ENOBUFS: 363 /* Tell source to slow down like source quench in IP? */ 364 goto freecopy; 365 366 case ENETUNREACH: /* shouldn't happen, checked above */ 367 case EHOSTUNREACH: 368 case ENETDOWN: 369 case EHOSTDOWN: 370 default: 371 type = ICMP6_DST_UNREACH; 372 code = ICMP6_DST_UNREACH_ADDR; 373 break; 374 } 375 icmp6_error(mcopy, type, code, 0); 376 return; 377 378 freecopy: 379 m_freem(mcopy); 380 return; 381 } 382