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 * $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 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 <netinet/ip6.h> 53 #include <netinet6/ip6_var.h> 54 #include <netinet/icmp6.h> 55 #include <netinet/in_systm.h> /* for ECN definitions */ 56 #include <netinet/ip.h> /* for ECN definitions */ 57 58 /* 59 * Define it to get a correct behavior on per-interface statistics. 60 * You will need to perform an extra routing table lookup, per fragment, 61 * to do it. This may, or may not be, a performance hit. 62 */ 63 #define IN6_IFSTAT_STRICT 64 65 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 66 static void frag6_deq(struct ip6asfrag *); 67 static void frag6_insque(struct ip6q *, struct ip6q *); 68 static void frag6_remque(struct ip6q *); 69 static void frag6_freef(struct ip6q *); 70 71 static struct mtx ip6qlock; 72 /* 73 * These fields all protected by ip6qlock. 74 */ 75 static u_int frag6_nfragpackets; 76 static u_int frag6_nfrags; 77 static struct ip6q ip6q; /* ip6 reassemble queue */ 78 79 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 81 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 83 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84 85 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 86 87 /* 88 * Initialise reassembly queue and fragment identifier. 89 */ 90 static void 91 frag6_change(void *tag) 92 { 93 94 ip6_maxfragpackets = nmbclusters / 4; 95 ip6_maxfrags = nmbclusters / 4; 96 } 97 98 void 99 frag6_init(void) 100 { 101 102 ip6_maxfragpackets = nmbclusters / 4; 103 ip6_maxfrags = nmbclusters / 4; 104 EVENTHANDLER_REGISTER(nmbclusters_change, 105 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 106 107 IP6Q_LOCK_INIT(); 108 109 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 110 } 111 112 /* 113 * In RFC2460, fragment and reassembly rule do not agree with each other, 114 * in terms of next header field handling in fragment header. 115 * While the sender will use the same value for all of the fragmented packets, 116 * receiver is suggested not to check the consistency. 117 * 118 * fragment rule (p20): 119 * (2) A Fragment header containing: 120 * The Next Header value that identifies the first header of 121 * the Fragmentable Part of the original packet. 122 * -> next header field is same for all fragments 123 * 124 * reassembly rule (p21): 125 * The Next Header field of the last header of the Unfragmentable 126 * Part is obtained from the Next Header field of the first 127 * fragment's Fragment header. 128 * -> should grab it from the first fragment only 129 * 130 * The following note also contradicts with fragment rule - noone is going to 131 * send different fragment with different next header field. 132 * 133 * additional note (p22): 134 * The Next Header values in the Fragment headers of different 135 * fragments of the same original packet may differ. Only the value 136 * from the Offset zero fragment packet is used for reassembly. 137 * -> should grab it from the first fragment only 138 * 139 * There is no explicit reason given in the RFC. Historical reason maybe? 140 */ 141 /* 142 * Fragment input 143 */ 144 int 145 frag6_input(struct mbuf **mp, int *offp, int proto) 146 { 147 struct mbuf *m = *mp, *t; 148 struct ip6_hdr *ip6; 149 struct ip6_frag *ip6f; 150 struct ip6q *q6; 151 struct ip6asfrag *af6, *ip6af, *af6dwn; 152 #ifdef IN6_IFSTAT_STRICT 153 struct in6_ifaddr *ia; 154 #endif 155 int offset = *offp, nxt, i, next; 156 int first_frag = 0; 157 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 158 struct ifnet *dstifp; 159 u_int8_t ecn, ecn0; 160 #if 0 161 char ip6buf[INET6_ADDRSTRLEN]; 162 #endif 163 164 ip6 = mtod(m, struct ip6_hdr *); 165 #ifndef PULLDOWN_TEST 166 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 167 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 168 #else 169 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 170 if (ip6f == NULL) 171 return (IPPROTO_DONE); 172 #endif 173 174 dstifp = NULL; 175 #ifdef IN6_IFSTAT_STRICT 176 /* find the destination interface of the packet. */ 177 if ((ia = ip6_getdstifaddr(m)) != NULL) 178 dstifp = ia->ia_ifp; 179 #else 180 /* we are violating the spec, this is not the destination interface */ 181 if ((m->m_flags & M_PKTHDR) != 0) 182 dstifp = m->m_pkthdr.rcvif; 183 #endif 184 185 /* jumbo payload can't contain a fragment header */ 186 if (ip6->ip6_plen == 0) { 187 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 188 in6_ifstat_inc(dstifp, ifs6_reass_fail); 189 return IPPROTO_DONE; 190 } 191 192 /* 193 * check whether fragment packet's fragment length is 194 * multiple of 8 octets. 195 * sizeof(struct ip6_frag) == 8 196 * sizeof(struct ip6_hdr) = 40 197 */ 198 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 199 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 200 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 201 offsetof(struct ip6_hdr, ip6_plen)); 202 in6_ifstat_inc(dstifp, ifs6_reass_fail); 203 return IPPROTO_DONE; 204 } 205 206 ip6stat.ip6s_fragments++; 207 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 208 209 /* offset now points to data portion */ 210 offset += sizeof(struct ip6_frag); 211 212 IP6Q_LOCK(); 213 214 /* 215 * Enforce upper bound on number of fragments. 216 * If maxfrag is 0, never accept fragments. 217 * If maxfrag is -1, accept all fragments without limitation. 218 */ 219 if (ip6_maxfrags < 0) 220 ; 221 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 222 goto dropfrag; 223 224 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 225 if (ip6f->ip6f_ident == q6->ip6q_ident && 226 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 227 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 228 break; 229 230 if (q6 == &ip6q) { 231 /* 232 * the first fragment to arrive, create a reassembly queue. 233 */ 234 first_frag = 1; 235 236 /* 237 * Enforce upper bound on number of fragmented packets 238 * for which we attempt reassembly; 239 * If maxfragpackets is 0, never accept fragments. 240 * If maxfragpackets is -1, accept all fragments without 241 * limitation. 242 */ 243 if (ip6_maxfragpackets < 0) 244 ; 245 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 246 goto dropfrag; 247 frag6_nfragpackets++; 248 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 249 M_NOWAIT); 250 if (q6 == NULL) 251 goto dropfrag; 252 bzero(q6, sizeof(*q6)); 253 254 frag6_insque(q6, &ip6q); 255 256 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 257 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 258 #ifdef notyet 259 q6->ip6q_nxtp = (u_char *)nxtp; 260 #endif 261 q6->ip6q_ident = ip6f->ip6f_ident; 262 q6->ip6q_ttl = IPV6_FRAGTTL; 263 q6->ip6q_src = ip6->ip6_src; 264 q6->ip6q_dst = ip6->ip6_dst; 265 q6->ip6q_ecn = 266 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 267 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 268 269 q6->ip6q_nfrag = 0; 270 } 271 272 /* 273 * If it's the 1st fragment, record the length of the 274 * unfragmentable part and the next header of the fragment header. 275 */ 276 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 277 if (fragoff == 0) { 278 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 279 sizeof(struct ip6_frag); 280 q6->ip6q_nxt = ip6f->ip6f_nxt; 281 } 282 283 /* 284 * Check that the reassembled packet would not exceed 65535 bytes 285 * in size. 286 * If it would exceed, discard the fragment and return an ICMP error. 287 */ 288 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 289 if (q6->ip6q_unfrglen >= 0) { 290 /* The 1st fragment has already arrived. */ 291 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 292 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 293 offset - sizeof(struct ip6_frag) + 294 offsetof(struct ip6_frag, ip6f_offlg)); 295 IP6Q_UNLOCK(); 296 return (IPPROTO_DONE); 297 } 298 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 299 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 300 offset - sizeof(struct ip6_frag) + 301 offsetof(struct ip6_frag, ip6f_offlg)); 302 IP6Q_UNLOCK(); 303 return (IPPROTO_DONE); 304 } 305 /* 306 * If it's the first fragment, do the above check for each 307 * fragment already stored in the reassembly queue. 308 */ 309 if (fragoff == 0) { 310 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 311 af6 = af6dwn) { 312 af6dwn = af6->ip6af_down; 313 314 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 315 IPV6_MAXPACKET) { 316 struct mbuf *merr = IP6_REASS_MBUF(af6); 317 struct ip6_hdr *ip6err; 318 int erroff = af6->ip6af_offset; 319 320 /* dequeue the fragment. */ 321 frag6_deq(af6); 322 free(af6, M_FTABLE); 323 324 /* adjust pointer. */ 325 ip6err = mtod(merr, struct ip6_hdr *); 326 327 /* 328 * Restore source and destination addresses 329 * in the erroneous IPv6 header. 330 */ 331 ip6err->ip6_src = q6->ip6q_src; 332 ip6err->ip6_dst = q6->ip6q_dst; 333 334 icmp6_error(merr, ICMP6_PARAM_PROB, 335 ICMP6_PARAMPROB_HEADER, 336 erroff - sizeof(struct ip6_frag) + 337 offsetof(struct ip6_frag, ip6f_offlg)); 338 } 339 } 340 } 341 342 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 343 M_NOWAIT); 344 if (ip6af == NULL) 345 goto dropfrag; 346 bzero(ip6af, sizeof(*ip6af)); 347 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 348 ip6af->ip6af_off = fragoff; 349 ip6af->ip6af_frglen = frgpartlen; 350 ip6af->ip6af_offset = offset; 351 IP6_REASS_MBUF(ip6af) = m; 352 353 if (first_frag) { 354 af6 = (struct ip6asfrag *)q6; 355 goto insert; 356 } 357 358 /* 359 * Handle ECN by comparing this segment with the first one; 360 * if CE is set, do not lose CE. 361 * drop if CE and not-ECT are mixed for the same packet. 362 */ 363 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 364 ecn0 = q6->ip6q_ecn; 365 if (ecn == IPTOS_ECN_CE) { 366 if (ecn0 == IPTOS_ECN_NOTECT) { 367 free(ip6af, M_FTABLE); 368 goto dropfrag; 369 } 370 if (ecn0 != IPTOS_ECN_CE) 371 q6->ip6q_ecn = IPTOS_ECN_CE; 372 } 373 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 374 free(ip6af, M_FTABLE); 375 goto dropfrag; 376 } 377 378 /* 379 * Find a segment which begins after this one does. 380 */ 381 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 382 af6 = af6->ip6af_down) 383 if (af6->ip6af_off > ip6af->ip6af_off) 384 break; 385 386 #if 0 387 /* 388 * If there is a preceding segment, it may provide some of 389 * our data already. If so, drop the data from the incoming 390 * segment. If it provides all of our data, drop us. 391 */ 392 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 393 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 394 - ip6af->ip6af_off; 395 if (i > 0) { 396 if (i >= ip6af->ip6af_frglen) 397 goto dropfrag; 398 m_adj(IP6_REASS_MBUF(ip6af), i); 399 ip6af->ip6af_off += i; 400 ip6af->ip6af_frglen -= i; 401 } 402 } 403 404 /* 405 * While we overlap succeeding segments trim them or, 406 * if they are completely covered, dequeue them. 407 */ 408 while (af6 != (struct ip6asfrag *)q6 && 409 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 410 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 411 if (i < af6->ip6af_frglen) { 412 af6->ip6af_frglen -= i; 413 af6->ip6af_off += i; 414 m_adj(IP6_REASS_MBUF(af6), i); 415 break; 416 } 417 af6 = af6->ip6af_down; 418 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 419 frag6_deq(af6->ip6af_up); 420 } 421 #else 422 /* 423 * If the incoming framgent overlaps some existing fragments in 424 * the reassembly queue, drop it, since it is dangerous to override 425 * existing fragments from a security point of view. 426 * We don't know which fragment is the bad guy - here we trust 427 * fragment that came in earlier, with no real reason. 428 * 429 * Note: due to changes after disabling this part, mbuf passed to 430 * m_adj() below now does not meet the requirement. 431 */ 432 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 433 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 434 - ip6af->ip6af_off; 435 if (i > 0) { 436 #if 0 /* suppress the noisy log */ 437 log(LOG_ERR, "%d bytes of a fragment from %s " 438 "overlaps the previous fragment\n", 439 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 440 #endif 441 free(ip6af, M_FTABLE); 442 goto dropfrag; 443 } 444 } 445 if (af6 != (struct ip6asfrag *)q6) { 446 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 447 if (i > 0) { 448 #if 0 /* suppress the noisy log */ 449 log(LOG_ERR, "%d bytes of a fragment from %s " 450 "overlaps the succeeding fragment", 451 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 452 #endif 453 free(ip6af, M_FTABLE); 454 goto dropfrag; 455 } 456 } 457 #endif 458 459 insert: 460 461 /* 462 * Stick new segment in its place; 463 * check for complete reassembly. 464 * Move to front of packet queue, as we are 465 * the most recently active fragmented packet. 466 */ 467 frag6_enq(ip6af, af6->ip6af_up); 468 frag6_nfrags++; 469 q6->ip6q_nfrag++; 470 #if 0 /* xxx */ 471 if (q6 != ip6q.ip6q_next) { 472 frag6_remque(q6); 473 frag6_insque(q6, &ip6q); 474 } 475 #endif 476 next = 0; 477 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 478 af6 = af6->ip6af_down) { 479 if (af6->ip6af_off != next) { 480 IP6Q_UNLOCK(); 481 return IPPROTO_DONE; 482 } 483 next += af6->ip6af_frglen; 484 } 485 if (af6->ip6af_up->ip6af_mff) { 486 IP6Q_UNLOCK(); 487 return IPPROTO_DONE; 488 } 489 490 /* 491 * Reassembly is complete; concatenate fragments. 492 */ 493 ip6af = q6->ip6q_down; 494 t = m = IP6_REASS_MBUF(ip6af); 495 af6 = ip6af->ip6af_down; 496 frag6_deq(ip6af); 497 while (af6 != (struct ip6asfrag *)q6) { 498 af6dwn = af6->ip6af_down; 499 frag6_deq(af6); 500 while (t->m_next) 501 t = t->m_next; 502 t->m_next = IP6_REASS_MBUF(af6); 503 m_adj(t->m_next, af6->ip6af_offset); 504 free(af6, M_FTABLE); 505 af6 = af6dwn; 506 } 507 508 /* adjust offset to point where the original next header starts */ 509 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 510 free(ip6af, M_FTABLE); 511 ip6 = mtod(m, struct ip6_hdr *); 512 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 513 if (q6->ip6q_ecn == IPTOS_ECN_CE) 514 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 515 nxt = q6->ip6q_nxt; 516 #ifdef notyet 517 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 518 #endif 519 520 /* Delete frag6 header */ 521 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 522 /* This is the only possible case with !PULLDOWN_TEST */ 523 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 524 offset); 525 m->m_data += sizeof(struct ip6_frag); 526 m->m_len -= sizeof(struct ip6_frag); 527 } else { 528 /* this comes with no copy if the boundary is on cluster */ 529 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 530 frag6_remque(q6); 531 frag6_nfrags -= q6->ip6q_nfrag; 532 free(q6, M_FTABLE); 533 frag6_nfragpackets--; 534 goto dropfrag; 535 } 536 m_adj(t, sizeof(struct ip6_frag)); 537 m_cat(m, t); 538 } 539 540 /* 541 * Store NXT to the original. 542 */ 543 { 544 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 545 *prvnxtp = nxt; 546 } 547 548 frag6_remque(q6); 549 frag6_nfrags -= q6->ip6q_nfrag; 550 free(q6, M_FTABLE); 551 frag6_nfragpackets--; 552 553 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 554 int plen = 0; 555 for (t = m; t; t = t->m_next) 556 plen += t->m_len; 557 m->m_pkthdr.len = plen; 558 } 559 560 ip6stat.ip6s_reassembled++; 561 in6_ifstat_inc(dstifp, ifs6_reass_ok); 562 563 /* 564 * Tell launch routine the next header 565 */ 566 567 *mp = m; 568 *offp = offset; 569 570 IP6Q_UNLOCK(); 571 return nxt; 572 573 dropfrag: 574 IP6Q_UNLOCK(); 575 in6_ifstat_inc(dstifp, ifs6_reass_fail); 576 ip6stat.ip6s_fragdropped++; 577 m_freem(m); 578 return IPPROTO_DONE; 579 } 580 581 /* 582 * Free a fragment reassembly header and all 583 * associated datagrams. 584 */ 585 void 586 frag6_freef(struct ip6q *q6) 587 { 588 struct ip6asfrag *af6, *down6; 589 590 IP6Q_LOCK_ASSERT(); 591 592 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 593 af6 = down6) { 594 struct mbuf *m = IP6_REASS_MBUF(af6); 595 596 down6 = af6->ip6af_down; 597 frag6_deq(af6); 598 599 /* 600 * Return ICMP time exceeded error for the 1st fragment. 601 * Just free other fragments. 602 */ 603 if (af6->ip6af_off == 0) { 604 struct ip6_hdr *ip6; 605 606 /* adjust pointer */ 607 ip6 = mtod(m, struct ip6_hdr *); 608 609 /* restore source and destination addresses */ 610 ip6->ip6_src = q6->ip6q_src; 611 ip6->ip6_dst = q6->ip6q_dst; 612 613 icmp6_error(m, ICMP6_TIME_EXCEEDED, 614 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 615 } else 616 m_freem(m); 617 free(af6, M_FTABLE); 618 } 619 frag6_remque(q6); 620 frag6_nfrags -= q6->ip6q_nfrag; 621 free(q6, M_FTABLE); 622 frag6_nfragpackets--; 623 } 624 625 /* 626 * Put an ip fragment on a reassembly chain. 627 * Like insque, but pointers in middle of structure. 628 */ 629 void 630 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 631 { 632 633 IP6Q_LOCK_ASSERT(); 634 635 af6->ip6af_up = up6; 636 af6->ip6af_down = up6->ip6af_down; 637 up6->ip6af_down->ip6af_up = af6; 638 up6->ip6af_down = af6; 639 } 640 641 /* 642 * To frag6_enq as remque is to insque. 643 */ 644 void 645 frag6_deq(struct ip6asfrag *af6) 646 { 647 648 IP6Q_LOCK_ASSERT(); 649 650 af6->ip6af_up->ip6af_down = af6->ip6af_down; 651 af6->ip6af_down->ip6af_up = af6->ip6af_up; 652 } 653 654 void 655 frag6_insque(struct ip6q *new, struct ip6q *old) 656 { 657 658 IP6Q_LOCK_ASSERT(); 659 660 new->ip6q_prev = old; 661 new->ip6q_next = old->ip6q_next; 662 old->ip6q_next->ip6q_prev= new; 663 old->ip6q_next = new; 664 } 665 666 void 667 frag6_remque(struct ip6q *p6) 668 { 669 670 IP6Q_LOCK_ASSERT(); 671 672 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 673 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 674 } 675 676 /* 677 * IPv6 reassembling timer processing; 678 * if a timer expires on a reassembly 679 * queue, discard it. 680 */ 681 void 682 frag6_slowtimo(void) 683 { 684 struct ip6q *q6; 685 686 #if 0 687 GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */ 688 #endif 689 690 IP6Q_LOCK(); 691 q6 = ip6q.ip6q_next; 692 if (q6) 693 while (q6 != &ip6q) { 694 --q6->ip6q_ttl; 695 q6 = q6->ip6q_next; 696 if (q6->ip6q_prev->ip6q_ttl == 0) { 697 ip6stat.ip6s_fragtimeout++; 698 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 699 frag6_freef(q6->ip6q_prev); 700 } 701 } 702 /* 703 * If we are over the maximum number of fragments 704 * (due to the limit being lowered), drain off 705 * enough to get down to the new limit. 706 */ 707 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 708 ip6q.ip6q_prev) { 709 ip6stat.ip6s_fragoverflow++; 710 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 711 frag6_freef(ip6q.ip6q_prev); 712 } 713 IP6Q_UNLOCK(); 714 715 #if 0 716 /* 717 * Routing changes might produce a better route than we last used; 718 * make sure we notice eventually, even if forwarding only for one 719 * destination and the cache is never replaced. 720 */ 721 if (ip6_forward_rt.ro_rt) { 722 RTFREE(ip6_forward_rt.ro_rt); 723 ip6_forward_rt.ro_rt = 0; 724 } 725 if (ipsrcchk_rt.ro_rt) { 726 RTFREE(ipsrcchk_rt.ro_rt); 727 ipsrcchk_rt.ro_rt = 0; 728 } 729 #endif 730 } 731 732 /* 733 * Drain off all datagram fragments. 734 */ 735 void 736 frag6_drain(void) 737 { 738 739 if (IP6Q_TRYLOCK() == 0) 740 return; 741 while (ip6q.ip6q_next != &ip6q) { 742 ip6stat.ip6s_fragdropped++; 743 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 744 frag6_freef(ip6q.ip6q_next); 745 } 746 IP6Q_UNLOCK(); 747 } 748