1 /* $FreeBSD$ */ 2 /* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 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 "opt_inet.h" 34 #include "opt_inet6.h" 35 #include "opt_ipsec.h" 36 #include "opt_ipstealth.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/malloc.h> 41 #include <sys/mbuf.h> 42 #include <sys/domain.h> 43 #include <sys/protosw.h> 44 #include <sys/socket.h> 45 #include <sys/errno.h> 46 #include <sys/time.h> 47 #include <sys/kernel.h> 48 #include <sys/syslog.h> 49 50 #include <net/if.h> 51 #include <net/route.h> 52 #include <net/pfil.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_var.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_var.h> 59 #include <netinet6/in6_var.h> 60 #include <netinet/ip6.h> 61 #include <netinet6/ip6_var.h> 62 #include <netinet6/scope6_var.h> 63 #include <netinet/icmp6.h> 64 #include <netinet6/nd6.h> 65 66 #include <netinet/in_pcb.h> 67 68 #ifdef IPSEC 69 #include <netipsec/ipsec.h> 70 #include <netipsec/ipsec6.h> 71 #include <netipsec/key.h> 72 #endif /* IPSEC */ 73 74 #include <netinet6/ip6protosw.h> 75 76 struct route_in6 ip6_forward_rt; 77 78 /* 79 * Forward a packet. If some error occurs return the sender 80 * an icmp packet. Note we can't always generate a meaningful 81 * icmp message because icmp doesn't have a large enough repertoire 82 * of codes and types. 83 * 84 * If not forwarding, just drop the packet. This could be confusing 85 * if ipforwarding was zero but some routing protocol was advancing 86 * us as a gateway to somewhere. However, we must let the routing 87 * protocol deal with that. 88 * 89 */ 90 void 91 ip6_forward(struct mbuf *m, int srcrt) 92 { 93 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 94 struct sockaddr_in6 *dst = NULL; 95 struct rtentry *rt = NULL; 96 int error, type = 0, code = 0; 97 struct mbuf *mcopy = NULL; 98 struct ifnet *origifp; /* maybe unnecessary */ 99 u_int32_t inzone, outzone; 100 struct in6_addr src_in6, dst_in6; 101 #ifdef IPSEC 102 struct secpolicy *sp = NULL; 103 int ipsecrt = 0; 104 #endif 105 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN]; 106 107 GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */ 108 109 #ifdef IPSEC 110 /* 111 * Check AH/ESP integrity. 112 */ 113 /* 114 * Don't increment ip6s_cantforward because this is the check 115 * before forwarding packet actually. 116 */ 117 if (ipsec6_in_reject(m, NULL)) { 118 ipsec6stat.in_polvio++; 119 m_freem(m); 120 return; 121 } 122 #endif /* IPSEC */ 123 124 /* 125 * Do not forward packets to multicast destination (should be handled 126 * by ip6_mforward(). 127 * Do not forward packets with unspecified source. It was discussed 128 * in July 2000, on the ipngwg mailing list. 129 */ 130 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 131 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 132 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 133 ip6stat.ip6s_cantforward++; 134 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 135 if (ip6_log_time + ip6_log_interval < time_second) { 136 ip6_log_time = time_second; 137 log(LOG_DEBUG, 138 "cannot forward " 139 "from %s to %s nxt %d received on %s\n", 140 ip6_sprintf(ip6bufs, &ip6->ip6_src), 141 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 142 ip6->ip6_nxt, 143 if_name(m->m_pkthdr.rcvif)); 144 } 145 m_freem(m); 146 return; 147 } 148 149 #ifdef IPSTEALTH 150 if (!ip6stealth) { 151 #endif 152 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 153 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 154 icmp6_error(m, ICMP6_TIME_EXCEEDED, 155 ICMP6_TIME_EXCEED_TRANSIT, 0); 156 return; 157 } 158 ip6->ip6_hlim -= IPV6_HLIMDEC; 159 160 #ifdef IPSTEALTH 161 } 162 #endif 163 164 /* 165 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 166 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 167 * we need to generate an ICMP6 message to the src. 168 * Thanks to M_EXT, in most cases copy will not occur. 169 * 170 * It is important to save it before IPsec processing as IPsec 171 * processing may modify the mbuf. 172 */ 173 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 174 175 #ifdef IPSEC 176 /* get a security policy for this packet */ 177 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 178 IP_FORWARDING, &error); 179 if (sp == NULL) { 180 ipsec6stat.out_inval++; 181 ip6stat.ip6s_cantforward++; 182 if (mcopy) { 183 #if 0 184 /* XXX: what icmp ? */ 185 #else 186 m_freem(mcopy); 187 #endif 188 } 189 m_freem(m); 190 return; 191 } 192 193 error = 0; 194 195 /* check policy */ 196 switch (sp->policy) { 197 case IPSEC_POLICY_DISCARD: 198 /* 199 * This packet is just discarded. 200 */ 201 ipsec6stat.out_polvio++; 202 ip6stat.ip6s_cantforward++; 203 KEY_FREESP(&sp); 204 if (mcopy) { 205 #if 0 206 /* XXX: what icmp ? */ 207 #else 208 m_freem(mcopy); 209 #endif 210 } 211 m_freem(m); 212 return; 213 214 case IPSEC_POLICY_BYPASS: 215 case IPSEC_POLICY_NONE: 216 /* no need to do IPsec. */ 217 KEY_FREESP(&sp); 218 goto skip_ipsec; 219 220 case IPSEC_POLICY_IPSEC: 221 if (sp->req == NULL) { 222 /* XXX should be panic ? */ 223 printf("ip6_forward: No IPsec request specified.\n"); 224 ip6stat.ip6s_cantforward++; 225 KEY_FREESP(&sp); 226 if (mcopy) { 227 #if 0 228 /* XXX: what icmp ? */ 229 #else 230 m_freem(mcopy); 231 #endif 232 } 233 m_freem(m); 234 return; 235 } 236 /* do IPsec */ 237 break; 238 239 case IPSEC_POLICY_ENTRUST: 240 default: 241 /* should be panic ?? */ 242 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 243 KEY_FREESP(&sp); 244 goto skip_ipsec; 245 } 246 247 { 248 struct ipsecrequest *isr = NULL; 249 struct ipsec_output_state state; 250 251 /* 252 * when the kernel forwards a packet, it is not proper to apply 253 * IPsec transport mode to the packet is not proper. this check 254 * avoid from this. 255 * at present, if there is even a transport mode SA request in the 256 * security policy, the kernel does not apply IPsec to the packet. 257 * this check is not enough because the following case is valid. 258 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 259 */ 260 for (isr = sp->req; isr; isr = isr->next) { 261 if (isr->saidx.mode == IPSEC_MODE_ANY) 262 goto doipsectunnel; 263 if (isr->saidx.mode == IPSEC_MODE_TUNNEL) 264 goto doipsectunnel; 265 } 266 267 /* 268 * if there's no need for tunnel mode IPsec, skip. 269 */ 270 if (!isr) 271 goto skip_ipsec; 272 273 doipsectunnel: 274 /* 275 * All the extension headers will become inaccessible 276 * (since they can be encrypted). 277 * Don't panic, we need no more updates to extension headers 278 * on inner IPv6 packet (since they are now encapsulated). 279 * 280 * IPv6 [ESP|AH] IPv6 [extension headers] payload 281 */ 282 bzero(&state, sizeof(state)); 283 state.m = m; 284 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 285 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 286 287 error = ipsec6_output_tunnel(&state, sp, 0); 288 289 m = state.m; 290 KEY_FREESP(&sp); 291 292 if (error) { 293 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 294 switch (error) { 295 case EHOSTUNREACH: 296 case ENETUNREACH: 297 case EMSGSIZE: 298 case ENOBUFS: 299 case ENOMEM: 300 break; 301 default: 302 printf("ip6_output (ipsec): error code %d\n", error); 303 /* FALLTHROUGH */ 304 case ENOENT: 305 /* don't show these error codes to the user */ 306 break; 307 } 308 ip6stat.ip6s_cantforward++; 309 if (mcopy) { 310 #if 0 311 /* XXX: what icmp ? */ 312 #else 313 m_freem(mcopy); 314 #endif 315 } 316 m_freem(m); 317 return; 318 } else { 319 /* 320 * In the FAST IPSec case we have already 321 * re-injected the packet and it has been freed 322 * by the ipsec_done() function. So, just clean 323 * up after ourselves. 324 */ 325 m = NULL; 326 goto freecopy; 327 } 328 329 if ((m != NULL) && (ip6 != mtod(m, struct ip6_hdr *)) ){ 330 /* 331 * now tunnel mode headers are added. we are originating 332 * packet instead of forwarding the packet. 333 */ 334 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL, 335 NULL); 336 goto freecopy; 337 } 338 339 /* adjust pointer */ 340 dst = (struct sockaddr_in6 *)state.dst; 341 rt = state.ro ? state.ro->ro_rt : NULL; 342 if (dst != NULL && rt != NULL) 343 ipsecrt = 1; 344 } 345 skip_ipsec: 346 #endif /* IPSEC */ 347 348 #ifdef IPSEC 349 if (ipsecrt) 350 goto skip_routing; 351 #endif 352 353 dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 354 if (!srcrt) { 355 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ 356 if (ip6_forward_rt.ro_rt == 0 || 357 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 358 if (ip6_forward_rt.ro_rt) { 359 RTFREE(ip6_forward_rt.ro_rt); 360 ip6_forward_rt.ro_rt = 0; 361 } 362 363 /* this probably fails but give it a try again */ 364 rtalloc((struct route *)&ip6_forward_rt); 365 } 366 367 if (ip6_forward_rt.ro_rt == 0) { 368 ip6stat.ip6s_noroute++; 369 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 370 if (mcopy) { 371 icmp6_error(mcopy, ICMP6_DST_UNREACH, 372 ICMP6_DST_UNREACH_NOROUTE, 0); 373 } 374 m_freem(m); 375 return; 376 } 377 } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 378 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 379 if (ip6_forward_rt.ro_rt) { 380 RTFREE(ip6_forward_rt.ro_rt); 381 ip6_forward_rt.ro_rt = 0; 382 } 383 bzero(dst, sizeof(*dst)); 384 dst->sin6_len = sizeof(struct sockaddr_in6); 385 dst->sin6_family = AF_INET6; 386 dst->sin6_addr = ip6->ip6_dst; 387 388 rtalloc((struct route *)&ip6_forward_rt); 389 if (ip6_forward_rt.ro_rt == 0) { 390 ip6stat.ip6s_noroute++; 391 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 392 if (mcopy) { 393 icmp6_error(mcopy, ICMP6_DST_UNREACH, 394 ICMP6_DST_UNREACH_NOROUTE, 0); 395 } 396 m_freem(m); 397 return; 398 } 399 } 400 rt = ip6_forward_rt.ro_rt; 401 #ifdef IPSEC 402 skip_routing:; 403 #endif 404 405 /* 406 * Source scope check: if a packet can't be delivered to its 407 * destination for the reason that the destination is beyond the scope 408 * of the source address, discard the packet and return an icmp6 409 * destination unreachable error with Code 2 (beyond scope of source 410 * address). We use a local copy of ip6_src, since in6_setscope() 411 * will possibly modify its first argument. 412 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 413 */ 414 src_in6 = ip6->ip6_src; 415 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 416 /* XXX: this should not happen */ 417 ip6stat.ip6s_cantforward++; 418 ip6stat.ip6s_badscope++; 419 m_freem(m); 420 return; 421 } 422 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 423 ip6stat.ip6s_cantforward++; 424 ip6stat.ip6s_badscope++; 425 m_freem(m); 426 return; 427 } 428 if (inzone != outzone 429 #ifdef IPSEC 430 && !ipsecrt 431 #endif 432 ) { 433 ip6stat.ip6s_cantforward++; 434 ip6stat.ip6s_badscope++; 435 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 436 437 if (ip6_log_time + ip6_log_interval < time_second) { 438 ip6_log_time = time_second; 439 log(LOG_DEBUG, 440 "cannot forward " 441 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 442 ip6_sprintf(ip6bufs, &ip6->ip6_src), 443 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 444 ip6->ip6_nxt, 445 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 446 } 447 if (mcopy) 448 icmp6_error(mcopy, ICMP6_DST_UNREACH, 449 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 450 m_freem(m); 451 return; 452 } 453 454 /* 455 * Destination scope check: if a packet is going to break the scope 456 * zone of packet's destination address, discard it. This case should 457 * usually be prevented by appropriately-configured routing table, but 458 * we need an explicit check because we may mistakenly forward the 459 * packet to a different zone by (e.g.) a default route. 460 */ 461 dst_in6 = ip6->ip6_dst; 462 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 463 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 464 inzone != outzone) { 465 ip6stat.ip6s_cantforward++; 466 ip6stat.ip6s_badscope++; 467 m_freem(m); 468 return; 469 } 470 471 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 472 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 473 if (mcopy) { 474 u_long mtu; 475 #ifdef IPSEC 476 struct secpolicy *sp; 477 int ipsecerror; 478 size_t ipsechdrsiz; 479 #endif /* IPSEC */ 480 481 mtu = IN6_LINKMTU(rt->rt_ifp); 482 #ifdef IPSEC 483 /* 484 * When we do IPsec tunnel ingress, we need to play 485 * with the link value (decrement IPsec header size 486 * from mtu value). The code is much simpler than v4 487 * case, as we have the outgoing interface for 488 * encapsulated packet as "rt->rt_ifp". 489 */ 490 sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 491 IP_FORWARDING, &ipsecerror); 492 if (sp) { 493 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 494 IPSEC_DIR_OUTBOUND, NULL); 495 if (ipsechdrsiz < mtu) 496 mtu -= ipsechdrsiz; 497 } 498 499 /* 500 * if mtu becomes less than minimum MTU, 501 * tell minimum MTU (and I'll need to fragment it). 502 */ 503 if (mtu < IPV6_MMTU) 504 mtu = IPV6_MMTU; 505 #endif /* IPSEC */ 506 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 507 } 508 m_freem(m); 509 return; 510 } 511 512 if (rt->rt_flags & RTF_GATEWAY) 513 dst = (struct sockaddr_in6 *)rt->rt_gateway; 514 515 /* 516 * If we are to forward the packet using the same interface 517 * as one we got the packet from, perhaps we should send a redirect 518 * to sender to shortcut a hop. 519 * Only send redirect if source is sending directly to us, 520 * and if packet was not source routed (or has any options). 521 * Also, don't send redirect if forwarding using a route 522 * modified by a redirect. 523 */ 524 if (ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 525 #ifdef IPSEC 526 !ipsecrt && 527 #endif /* IPSEC */ 528 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 529 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 530 /* 531 * If the incoming interface is equal to the outgoing 532 * one, and the link attached to the interface is 533 * point-to-point, then it will be highly probable 534 * that a routing loop occurs. Thus, we immediately 535 * drop the packet and send an ICMPv6 error message. 536 * 537 * type/code is based on suggestion by Rich Draves. 538 * not sure if it is the best pick. 539 */ 540 icmp6_error(mcopy, ICMP6_DST_UNREACH, 541 ICMP6_DST_UNREACH_ADDR, 0); 542 m_freem(m); 543 return; 544 } 545 type = ND_REDIRECT; 546 } 547 548 /* 549 * Fake scoped addresses. Note that even link-local source or 550 * destinaion can appear, if the originating node just sends the 551 * packet to us (without address resolution for the destination). 552 * Since both icmp6_error and icmp6_redirect_output fill the embedded 553 * link identifiers, we can do this stuff after making a copy for 554 * returning an error. 555 */ 556 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 557 /* 558 * See corresponding comments in ip6_output. 559 * XXX: but is it possible that ip6_forward() sends a packet 560 * to a loopback interface? I don't think so, and thus 561 * I bark here. (jinmei@kame.net) 562 * XXX: it is common to route invalid packets to loopback. 563 * also, the codepath will be visited on use of ::1 in 564 * rthdr. (itojun) 565 */ 566 #if 1 567 if (0) 568 #else 569 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 570 #endif 571 { 572 printf("ip6_forward: outgoing interface is loopback. " 573 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 574 ip6_sprintf(ip6bufs, &ip6->ip6_src), 575 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 576 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 577 if_name(rt->rt_ifp)); 578 } 579 580 /* we can just use rcvif in forwarding. */ 581 origifp = m->m_pkthdr.rcvif; 582 } 583 else 584 origifp = rt->rt_ifp; 585 /* 586 * clear embedded scope identifiers if necessary. 587 * in6_clearscope will touch the addresses only when necessary. 588 */ 589 in6_clearscope(&ip6->ip6_src); 590 in6_clearscope(&ip6->ip6_dst); 591 592 /* Jump over all PFIL processing if hooks are not active. */ 593 if (!PFIL_HOOKED(&inet6_pfil_hook)) 594 goto pass; 595 596 /* Run through list of hooks for output packets. */ 597 error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL); 598 if (error != 0) 599 goto senderr; 600 if (m == NULL) 601 goto freecopy; 602 ip6 = mtod(m, struct ip6_hdr *); 603 604 pass: 605 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 606 if (error) { 607 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 608 ip6stat.ip6s_cantforward++; 609 } else { 610 ip6stat.ip6s_forward++; 611 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 612 if (type) 613 ip6stat.ip6s_redirectsent++; 614 else { 615 if (mcopy) 616 goto freecopy; 617 } 618 } 619 620 senderr: 621 if (mcopy == NULL) 622 return; 623 switch (error) { 624 case 0: 625 if (type == ND_REDIRECT) { 626 icmp6_redirect_output(mcopy, rt); 627 return; 628 } 629 goto freecopy; 630 631 case EMSGSIZE: 632 /* xxx MTU is constant in PPP? */ 633 goto freecopy; 634 635 case ENOBUFS: 636 /* Tell source to slow down like source quench in IP? */ 637 goto freecopy; 638 639 case ENETUNREACH: /* shouldn't happen, checked above */ 640 case EHOSTUNREACH: 641 case ENETDOWN: 642 case EHOSTDOWN: 643 default: 644 type = ICMP6_DST_UNREACH; 645 code = ICMP6_DST_UNREACH_ADDR; 646 break; 647 } 648 icmp6_error(mcopy, type, code, 0); 649 return; 650 651 freecopy: 652 m_freem(mcopy); 653 return; 654 } 655