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 <netinet6/ipsec.h> 70 #ifdef INET6 71 #include <netinet6/ipsec6.h> 72 #endif 73 #include <netkey/key.h> 74 #endif /* IPSEC */ 75 76 #ifdef FAST_IPSEC 77 #include <netipsec/ipsec.h> 78 #include <netipsec/ipsec6.h> 79 #include <netipsec/key.h> 80 #define IPSEC 81 #endif /* FAST_IPSEC */ 82 83 #include <netinet6/ip6protosw.h> 84 85 struct route_in6 ip6_forward_rt; 86 87 /* 88 * Forward a packet. If some error occurs return the sender 89 * an icmp packet. Note we can't always generate a meaningful 90 * icmp message because icmp doesn't have a large enough repertoire 91 * of codes and types. 92 * 93 * If not forwarding, just drop the packet. This could be confusing 94 * if ipforwarding was zero but some routing protocol was advancing 95 * us as a gateway to somewhere. However, we must let the routing 96 * protocol deal with that. 97 * 98 */ 99 100 void 101 ip6_forward(m, srcrt) 102 struct mbuf *m; 103 int srcrt; 104 { 105 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 106 struct sockaddr_in6 *dst = NULL; 107 struct rtentry *rt = NULL; 108 int error, type = 0, code = 0; 109 struct mbuf *mcopy = NULL; 110 struct ifnet *origifp; /* maybe unnecessary */ 111 u_int32_t inzone, outzone; 112 struct in6_addr src_in6, dst_in6; 113 #ifdef IPSEC 114 struct secpolicy *sp = NULL; 115 int ipsecrt = 0; 116 #endif 117 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN]; 118 119 GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */ 120 121 #ifdef IPSEC 122 /* 123 * Check AH/ESP integrity. 124 */ 125 /* 126 * Don't increment ip6s_cantforward because this is the check 127 * before forwarding packet actually. 128 */ 129 if (ipsec6_in_reject(m, NULL)) { 130 #if !defined(FAST_IPSEC) 131 ipsec6stat.in_polvio++; 132 #endif 133 m_freem(m); 134 return; 135 } 136 #endif /* IPSEC */ 137 138 /* 139 * Do not forward packets to multicast destination (should be handled 140 * by ip6_mforward(). 141 * Do not forward packets with unspecified source. It was discussed 142 * in July 2000, on the ipngwg mailing list. 143 */ 144 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 145 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 146 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 147 ip6stat.ip6s_cantforward++; 148 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 149 if (ip6_log_time + ip6_log_interval < time_second) { 150 ip6_log_time = time_second; 151 log(LOG_DEBUG, 152 "cannot forward " 153 "from %s to %s nxt %d received on %s\n", 154 ip6_sprintf(ip6bufs, &ip6->ip6_src), 155 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 156 ip6->ip6_nxt, 157 if_name(m->m_pkthdr.rcvif)); 158 } 159 m_freem(m); 160 return; 161 } 162 163 #ifdef IPSTEALTH 164 if (!ip6stealth) { 165 #endif 166 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 167 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 168 icmp6_error(m, ICMP6_TIME_EXCEEDED, 169 ICMP6_TIME_EXCEED_TRANSIT, 0); 170 return; 171 } 172 ip6->ip6_hlim -= IPV6_HLIMDEC; 173 174 #ifdef IPSTEALTH 175 } 176 #endif 177 178 /* 179 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 180 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 181 * we need to generate an ICMP6 message to the src. 182 * Thanks to M_EXT, in most cases copy will not occur. 183 * 184 * It is important to save it before IPsec processing as IPsec 185 * processing may modify the mbuf. 186 */ 187 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 188 189 #ifdef IPSEC 190 /* get a security policy for this packet */ 191 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 192 IP_FORWARDING, &error); 193 if (sp == NULL) { 194 ipsec6stat.out_inval++; 195 ip6stat.ip6s_cantforward++; 196 if (mcopy) { 197 #if 0 198 /* XXX: what icmp ? */ 199 #else 200 m_freem(mcopy); 201 #endif 202 } 203 m_freem(m); 204 return; 205 } 206 207 error = 0; 208 209 /* check policy */ 210 switch (sp->policy) { 211 case IPSEC_POLICY_DISCARD: 212 /* 213 * This packet is just discarded. 214 */ 215 ipsec6stat.out_polvio++; 216 ip6stat.ip6s_cantforward++; 217 key_freesp(sp); 218 if (mcopy) { 219 #if 0 220 /* XXX: what icmp ? */ 221 #else 222 m_freem(mcopy); 223 #endif 224 } 225 m_freem(m); 226 return; 227 228 case IPSEC_POLICY_BYPASS: 229 case IPSEC_POLICY_NONE: 230 /* no need to do IPsec. */ 231 key_freesp(sp); 232 goto skip_ipsec; 233 234 case IPSEC_POLICY_IPSEC: 235 if (sp->req == NULL) { 236 /* XXX should be panic ? */ 237 printf("ip6_forward: No IPsec request specified.\n"); 238 ip6stat.ip6s_cantforward++; 239 key_freesp(sp); 240 if (mcopy) { 241 #if 0 242 /* XXX: what icmp ? */ 243 #else 244 m_freem(mcopy); 245 #endif 246 } 247 m_freem(m); 248 return; 249 } 250 /* do IPsec */ 251 break; 252 253 case IPSEC_POLICY_ENTRUST: 254 default: 255 /* should be panic ?? */ 256 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 257 key_freesp(sp); 258 goto skip_ipsec; 259 } 260 261 { 262 struct ipsecrequest *isr = NULL; 263 struct ipsec_output_state state; 264 265 /* 266 * when the kernel forwards a packet, it is not proper to apply 267 * IPsec transport mode to the packet is not proper. this check 268 * avoid from this. 269 * at present, if there is even a transport mode SA request in the 270 * security policy, the kernel does not apply IPsec to the packet. 271 * this check is not enough because the following case is valid. 272 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 273 */ 274 for (isr = sp->req; isr; isr = isr->next) { 275 if (isr->saidx.mode == IPSEC_MODE_ANY) 276 goto doipsectunnel; 277 if (isr->saidx.mode == IPSEC_MODE_TUNNEL) 278 goto doipsectunnel; 279 } 280 281 /* 282 * if there's no need for tunnel mode IPsec, skip. 283 */ 284 if (!isr) 285 goto skip_ipsec; 286 287 doipsectunnel: 288 /* 289 * All the extension headers will become inaccessible 290 * (since they can be encrypted). 291 * Don't panic, we need no more updates to extension headers 292 * on inner IPv6 packet (since they are now encapsulated). 293 * 294 * IPv6 [ESP|AH] IPv6 [extension headers] payload 295 */ 296 bzero(&state, sizeof(state)); 297 state.m = m; 298 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 299 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 300 301 error = ipsec6_output_tunnel(&state, sp, 0); 302 303 m = state.m; 304 key_freesp(sp); 305 306 if (error) { 307 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 308 switch (error) { 309 case EHOSTUNREACH: 310 case ENETUNREACH: 311 case EMSGSIZE: 312 case ENOBUFS: 313 case ENOMEM: 314 break; 315 default: 316 printf("ip6_output (ipsec): error code %d\n", error); 317 /* FALLTHROUGH */ 318 case ENOENT: 319 /* don't show these error codes to the user */ 320 break; 321 } 322 ip6stat.ip6s_cantforward++; 323 if (mcopy) { 324 #if 0 325 /* XXX: what icmp ? */ 326 #else 327 m_freem(mcopy); 328 #endif 329 } 330 m_freem(m); 331 return; 332 } 333 334 if (ip6 != mtod(m, struct ip6_hdr *)) { 335 /* 336 * now tunnel mode headers are added. we are originating 337 * packet instead of forwarding the packet. 338 */ 339 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL, 340 NULL); 341 goto freecopy; 342 } 343 344 /* adjust pointer */ 345 dst = (struct sockaddr_in6 *)state.dst; 346 rt = state.ro ? state.ro->ro_rt : NULL; 347 if (dst != NULL && rt != NULL) 348 ipsecrt = 1; 349 } 350 skip_ipsec: 351 #endif /* IPSEC */ 352 353 #ifdef IPSEC 354 if (ipsecrt) 355 goto skip_routing; 356 #endif 357 358 dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 359 if (!srcrt) { 360 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ 361 if (ip6_forward_rt.ro_rt == 0 || 362 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 363 if (ip6_forward_rt.ro_rt) { 364 RTFREE(ip6_forward_rt.ro_rt); 365 ip6_forward_rt.ro_rt = 0; 366 } 367 368 /* this probably fails but give it a try again */ 369 rtalloc((struct route *)&ip6_forward_rt); 370 } 371 372 if (ip6_forward_rt.ro_rt == 0) { 373 ip6stat.ip6s_noroute++; 374 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 375 if (mcopy) { 376 icmp6_error(mcopy, ICMP6_DST_UNREACH, 377 ICMP6_DST_UNREACH_NOROUTE, 0); 378 } 379 m_freem(m); 380 return; 381 } 382 } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 383 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 384 if (ip6_forward_rt.ro_rt) { 385 RTFREE(ip6_forward_rt.ro_rt); 386 ip6_forward_rt.ro_rt = 0; 387 } 388 bzero(dst, sizeof(*dst)); 389 dst->sin6_len = sizeof(struct sockaddr_in6); 390 dst->sin6_family = AF_INET6; 391 dst->sin6_addr = ip6->ip6_dst; 392 393 rtalloc((struct route *)&ip6_forward_rt); 394 if (ip6_forward_rt.ro_rt == 0) { 395 ip6stat.ip6s_noroute++; 396 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 397 if (mcopy) { 398 icmp6_error(mcopy, ICMP6_DST_UNREACH, 399 ICMP6_DST_UNREACH_NOROUTE, 0); 400 } 401 m_freem(m); 402 return; 403 } 404 } 405 rt = ip6_forward_rt.ro_rt; 406 #ifdef IPSEC 407 skip_routing:; 408 #endif 409 410 /* 411 * Source scope check: if a packet can't be delivered to its 412 * destination for the reason that the destination is beyond the scope 413 * of the source address, discard the packet and return an icmp6 414 * destination unreachable error with Code 2 (beyond scope of source 415 * address). We use a local copy of ip6_src, since in6_setscope() 416 * will possibly modify its first argument. 417 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 418 */ 419 src_in6 = ip6->ip6_src; 420 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 421 /* XXX: this should not happen */ 422 ip6stat.ip6s_cantforward++; 423 ip6stat.ip6s_badscope++; 424 m_freem(m); 425 return; 426 } 427 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 428 ip6stat.ip6s_cantforward++; 429 ip6stat.ip6s_badscope++; 430 m_freem(m); 431 return; 432 } 433 if (inzone != outzone 434 #ifdef IPSEC 435 && !ipsecrt 436 #endif 437 ) { 438 ip6stat.ip6s_cantforward++; 439 ip6stat.ip6s_badscope++; 440 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 441 442 if (ip6_log_time + ip6_log_interval < time_second) { 443 ip6_log_time = time_second; 444 log(LOG_DEBUG, 445 "cannot forward " 446 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 447 ip6_sprintf(ip6bufs, &ip6->ip6_src), 448 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 449 ip6->ip6_nxt, 450 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 451 } 452 if (mcopy) 453 icmp6_error(mcopy, ICMP6_DST_UNREACH, 454 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 455 m_freem(m); 456 return; 457 } 458 459 /* 460 * Destination scope check: if a packet is going to break the scope 461 * zone of packet's destination address, discard it. This case should 462 * usually be prevented by appropriately-configured routing table, but 463 * we need an explicit check because we may mistakenly forward the 464 * packet to a different zone by (e.g.) a default route. 465 */ 466 dst_in6 = ip6->ip6_dst; 467 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 468 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 469 inzone != outzone) { 470 ip6stat.ip6s_cantforward++; 471 ip6stat.ip6s_badscope++; 472 m_freem(m); 473 return; 474 } 475 476 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 477 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 478 if (mcopy) { 479 u_long mtu; 480 #ifdef IPSEC 481 struct secpolicy *sp; 482 int ipsecerror; 483 size_t ipsechdrsiz; 484 #endif 485 486 mtu = IN6_LINKMTU(rt->rt_ifp); 487 #ifdef IPSEC 488 /* 489 * When we do IPsec tunnel ingress, we need to play 490 * with the link value (decrement IPsec header size 491 * from mtu value). The code is much simpler than v4 492 * case, as we have the outgoing interface for 493 * encapsulated packet as "rt->rt_ifp". 494 */ 495 sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 496 IP_FORWARDING, &ipsecerror); 497 if (sp) { 498 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 499 IPSEC_DIR_OUTBOUND, NULL); 500 if (ipsechdrsiz < mtu) 501 mtu -= ipsechdrsiz; 502 } 503 504 /* 505 * if mtu becomes less than minimum MTU, 506 * tell minimum MTU (and I'll need to fragment it). 507 */ 508 if (mtu < IPV6_MMTU) 509 mtu = IPV6_MMTU; 510 #endif 511 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 512 } 513 m_freem(m); 514 return; 515 } 516 517 if (rt->rt_flags & RTF_GATEWAY) 518 dst = (struct sockaddr_in6 *)rt->rt_gateway; 519 520 /* 521 * If we are to forward the packet using the same interface 522 * as one we got the packet from, perhaps we should send a redirect 523 * to sender to shortcut a hop. 524 * Only send redirect if source is sending directly to us, 525 * and if packet was not source routed (or has any options). 526 * Also, don't send redirect if forwarding using a route 527 * modified by a redirect. 528 */ 529 if (ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 530 #ifdef IPSEC 531 !ipsecrt && 532 #endif 533 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 534 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 535 /* 536 * If the incoming interface is equal to the outgoing 537 * one, and the link attached to the interface is 538 * point-to-point, then it will be highly probable 539 * that a routing loop occurs. Thus, we immediately 540 * drop the packet and send an ICMPv6 error message. 541 * 542 * type/code is based on suggestion by Rich Draves. 543 * not sure if it is the best pick. 544 */ 545 icmp6_error(mcopy, ICMP6_DST_UNREACH, 546 ICMP6_DST_UNREACH_ADDR, 0); 547 m_freem(m); 548 return; 549 } 550 type = ND_REDIRECT; 551 } 552 553 /* 554 * Fake scoped addresses. Note that even link-local source or 555 * destinaion can appear, if the originating node just sends the 556 * packet to us (without address resolution for the destination). 557 * Since both icmp6_error and icmp6_redirect_output fill the embedded 558 * link identifiers, we can do this stuff after making a copy for 559 * returning an error. 560 */ 561 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 562 /* 563 * See corresponding comments in ip6_output. 564 * XXX: but is it possible that ip6_forward() sends a packet 565 * to a loopback interface? I don't think so, and thus 566 * I bark here. (jinmei@kame.net) 567 * XXX: it is common to route invalid packets to loopback. 568 * also, the codepath will be visited on use of ::1 in 569 * rthdr. (itojun) 570 */ 571 #if 1 572 if (0) 573 #else 574 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 575 #endif 576 { 577 printf("ip6_forward: outgoing interface is loopback. " 578 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 579 ip6_sprintf(ip6bufs, &ip6->ip6_src), 580 ip6_sprintf(ip6bufd, &ip6->ip6_dst), 581 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 582 if_name(rt->rt_ifp)); 583 } 584 585 /* we can just use rcvif in forwarding. */ 586 origifp = m->m_pkthdr.rcvif; 587 } 588 else 589 origifp = rt->rt_ifp; 590 /* 591 * clear embedded scope identifiers if necessary. 592 * in6_clearscope will touch the addresses only when necessary. 593 */ 594 in6_clearscope(&ip6->ip6_src); 595 in6_clearscope(&ip6->ip6_dst); 596 597 /* Jump over all PFIL processing if hooks are not active. */ 598 if (!PFIL_HOOKED(&inet6_pfil_hook)) 599 goto pass; 600 601 /* Run through list of hooks for output packets. */ 602 error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL); 603 if (error != 0) 604 goto senderr; 605 if (m == NULL) 606 goto freecopy; 607 ip6 = mtod(m, struct ip6_hdr *); 608 609 pass: 610 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 611 if (error) { 612 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 613 ip6stat.ip6s_cantforward++; 614 } else { 615 ip6stat.ip6s_forward++; 616 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 617 if (type) 618 ip6stat.ip6s_redirectsent++; 619 else { 620 if (mcopy) 621 goto freecopy; 622 } 623 } 624 625 senderr: 626 if (mcopy == NULL) 627 return; 628 switch (error) { 629 case 0: 630 if (type == ND_REDIRECT) { 631 icmp6_redirect_output(mcopy, rt); 632 return; 633 } 634 goto freecopy; 635 636 case EMSGSIZE: 637 /* xxx MTU is constant in PPP? */ 638 goto freecopy; 639 640 case ENOBUFS: 641 /* Tell source to slow down like source quench in IP? */ 642 goto freecopy; 643 644 case ENETUNREACH: /* shouldn't happen, checked above */ 645 case EHOSTUNREACH: 646 case ENETDOWN: 647 case EHOSTDOWN: 648 default: 649 type = ICMP6_DST_UNREACH; 650 code = ICMP6_DST_UNREACH_ADDR; 651 break; 652 } 653 icmp6_error(mcopy, type, code, 0); 654 return; 655 656 freecopy: 657 m_freem(mcopy); 658 return; 659 } 660