1 /* $FreeBSD$ */ 2 /* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc 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 <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/malloc.h> 36 #include <sys/mbuf.h> 37 #include <sys/domain.h> 38 #include <sys/protosw.h> 39 #include <sys/socket.h> 40 #include <sys/errno.h> 41 #include <sys/time.h> 42 #include <sys/kernel.h> 43 #include <sys/syslog.h> 44 45 #include <net/if.h> 46 #include <net/route.h> 47 48 #include <netinet/in.h> 49 #include <netinet/in_var.h> 50 #include <netinet/ip6.h> 51 #include <netinet6/ip6_var.h> 52 #include <netinet/icmp6.h> 53 #include <netinet/in_systm.h> /* for ECN definitions */ 54 #include <netinet/ip.h> /* for ECN definitions */ 55 56 /* 57 * Define it to get a correct behavior on per-interface statistics. 58 * You will need to perform an extra routing table lookup, per fragment, 59 * to do it. This may, or may not be, a performance hit. 60 */ 61 #define IN6_IFSTAT_STRICT 62 63 static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 64 static void frag6_deq __P((struct ip6asfrag *)); 65 static void frag6_insque __P((struct ip6q *, struct ip6q *)); 66 static void frag6_remque __P((struct ip6q *)); 67 static void frag6_freef __P((struct ip6q *)); 68 69 static struct mtx ip6qlock; 70 /* 71 * These fields all protected by ip6qlock. 72 */ 73 static u_int frag6_nfragpackets; 74 static u_int frag6_nfrags; 75 static struct ip6q ip6q; /* ip6 reassemble queue */ 76 77 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 78 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 79 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 80 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 81 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 82 83 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 84 85 /* 86 * Initialise reassembly queue and fragment identifier. 87 */ 88 static void 89 frag6_change(void *tag) 90 { 91 92 ip6_maxfragpackets = nmbclusters / 4; 93 ip6_maxfrags = nmbclusters / 4; 94 } 95 96 void 97 frag6_init() 98 { 99 100 ip6_maxfragpackets = nmbclusters / 4; 101 ip6_maxfrags = nmbclusters / 4; 102 EVENTHANDLER_REGISTER(nmbclusters_change, 103 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 104 105 IP6Q_LOCK_INIT(); 106 107 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 108 } 109 110 /* 111 * In RFC2460, fragment and reassembly rule do not agree with each other, 112 * in terms of next header field handling in fragment header. 113 * While the sender will use the same value for all of the fragmented packets, 114 * receiver is suggested not to check the consistency. 115 * 116 * fragment rule (p20): 117 * (2) A Fragment header containing: 118 * The Next Header value that identifies the first header of 119 * the Fragmentable Part of the original packet. 120 * -> next header field is same for all fragments 121 * 122 * reassembly rule (p21): 123 * The Next Header field of the last header of the Unfragmentable 124 * Part is obtained from the Next Header field of the first 125 * fragment's Fragment header. 126 * -> should grab it from the first fragment only 127 * 128 * The following note also contradicts with fragment rule - noone is going to 129 * send different fragment with different next header field. 130 * 131 * additional note (p22): 132 * The Next Header values in the Fragment headers of different 133 * fragments of the same original packet may differ. Only the value 134 * from the Offset zero fragment packet is used for reassembly. 135 * -> should grab it from the first fragment only 136 * 137 * There is no explicit reason given in the RFC. Historical reason maybe? 138 */ 139 /* 140 * Fragment input 141 */ 142 int 143 frag6_input(mp, offp, proto) 144 struct mbuf **mp; 145 int *offp, 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; 160 161 ip6 = mtod(m, struct ip6_hdr *); 162 #ifndef PULLDOWN_TEST 163 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 164 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 165 #else 166 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 167 if (ip6f == NULL) 168 return (IPPROTO_DONE); 169 #endif 170 171 dstifp = NULL; 172 #ifdef IN6_IFSTAT_STRICT 173 /* find the destination interface of the packet. */ 174 if ((ia = ip6_getdstifaddr(m)) != NULL) 175 dstifp = ia->ia_ifp; 176 #else 177 /* we are violating the spec, this is not the destination interface */ 178 if ((m->m_flags & M_PKTHDR) != 0) 179 dstifp = m->m_pkthdr.rcvif; 180 #endif 181 182 /* jumbo payload can't contain a fragment header */ 183 if (ip6->ip6_plen == 0) { 184 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 185 in6_ifstat_inc(dstifp, ifs6_reass_fail); 186 return IPPROTO_DONE; 187 } 188 189 /* 190 * check whether fragment packet's fragment length is 191 * multiple of 8 octets. 192 * sizeof(struct ip6_frag) == 8 193 * sizeof(struct ip6_hdr) = 40 194 */ 195 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 196 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 197 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 198 offsetof(struct ip6_hdr, ip6_plen)); 199 in6_ifstat_inc(dstifp, ifs6_reass_fail); 200 return IPPROTO_DONE; 201 } 202 203 ip6stat.ip6s_fragments++; 204 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 205 206 /* offset now points to data portion */ 207 offset += sizeof(struct ip6_frag); 208 209 IP6Q_LOCK(); 210 211 /* 212 * Enforce upper bound on number of fragments. 213 * If maxfrag is 0, never accept fragments. 214 * If maxfrag is -1, accept all fragments without limitation. 215 */ 216 if (ip6_maxfrags < 0) 217 ; 218 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 219 goto dropfrag; 220 221 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 222 if (ip6f->ip6f_ident == q6->ip6q_ident && 223 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 224 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 225 break; 226 227 if (q6 == &ip6q) { 228 /* 229 * the first fragment to arrive, create a reassembly queue. 230 */ 231 first_frag = 1; 232 233 /* 234 * Enforce upper bound on number of fragmented packets 235 * for which we attempt reassembly; 236 * If maxfragpackets is 0, never accept fragments. 237 * If maxfragpackets is -1, accept all fragments without 238 * limitation. 239 */ 240 if (ip6_maxfragpackets < 0) 241 ; 242 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 243 goto dropfrag; 244 frag6_nfragpackets++; 245 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 246 M_NOWAIT); 247 if (q6 == NULL) 248 goto dropfrag; 249 bzero(q6, sizeof(*q6)); 250 251 frag6_insque(q6, &ip6q); 252 253 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 254 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 255 #ifdef notyet 256 q6->ip6q_nxtp = (u_char *)nxtp; 257 #endif 258 q6->ip6q_ident = ip6f->ip6f_ident; 259 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 260 q6->ip6q_ttl = IPV6_FRAGTTL; 261 q6->ip6q_src = ip6->ip6_src; 262 q6->ip6q_dst = ip6->ip6_dst; 263 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 264 265 q6->ip6q_nfrag = 0; 266 } 267 268 /* 269 * If it's the 1st fragment, record the length of the 270 * unfragmentable part and the next header of the fragment header. 271 */ 272 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 273 if (fragoff == 0) { 274 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 275 sizeof(struct ip6_frag); 276 q6->ip6q_nxt = ip6f->ip6f_nxt; 277 } 278 279 /* 280 * Check that the reassembled packet would not exceed 65535 bytes 281 * in size. 282 * If it would exceed, discard the fragment and return an ICMP error. 283 */ 284 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 285 if (q6->ip6q_unfrglen >= 0) { 286 /* The 1st fragment has already arrived. */ 287 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 288 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 289 offset - sizeof(struct ip6_frag) + 290 offsetof(struct ip6_frag, ip6f_offlg)); 291 IP6Q_UNLOCK(); 292 return (IPPROTO_DONE); 293 } 294 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 295 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 296 offset - sizeof(struct ip6_frag) + 297 offsetof(struct ip6_frag, ip6f_offlg)); 298 IP6Q_UNLOCK(); 299 return (IPPROTO_DONE); 300 } 301 /* 302 * If it's the first fragment, do the above check for each 303 * fragment already stored in the reassembly queue. 304 */ 305 if (fragoff == 0) { 306 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 307 af6 = af6dwn) { 308 af6dwn = af6->ip6af_down; 309 310 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 311 IPV6_MAXPACKET) { 312 struct mbuf *merr = IP6_REASS_MBUF(af6); 313 struct ip6_hdr *ip6err; 314 int erroff = af6->ip6af_offset; 315 316 /* dequeue the fragment. */ 317 frag6_deq(af6); 318 free(af6, M_FTABLE); 319 320 /* adjust pointer. */ 321 ip6err = mtod(merr, struct ip6_hdr *); 322 323 /* 324 * Restore source and destination addresses 325 * in the erroneous IPv6 header. 326 */ 327 ip6err->ip6_src = q6->ip6q_src; 328 ip6err->ip6_dst = q6->ip6q_dst; 329 330 icmp6_error(merr, ICMP6_PARAM_PROB, 331 ICMP6_PARAMPROB_HEADER, 332 erroff - sizeof(struct ip6_frag) + 333 offsetof(struct ip6_frag, ip6f_offlg)); 334 } 335 } 336 } 337 338 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 339 M_NOWAIT); 340 if (ip6af == NULL) 341 goto dropfrag; 342 bzero(ip6af, sizeof(*ip6af)); 343 ip6af->ip6af_head = ip6->ip6_flow; 344 ip6af->ip6af_len = ip6->ip6_plen; 345 ip6af->ip6af_nxt = ip6->ip6_nxt; 346 ip6af->ip6af_hlim = ip6->ip6_hlim; 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 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK; 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_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20); 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 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 430 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 431 - ip6af->ip6af_off; 432 if (i > 0) { 433 #if 0 /* suppress the noisy log */ 434 log(LOG_ERR, "%d bytes of a fragment from %s " 435 "overlaps the previous fragment\n", 436 i, ip6_sprintf(&q6->ip6q_src)); 437 #endif 438 free(ip6af, M_FTABLE); 439 goto dropfrag; 440 } 441 } 442 if (af6 != (struct ip6asfrag *)q6) { 443 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 444 if (i > 0) { 445 #if 0 /* suppress the noisy log */ 446 log(LOG_ERR, "%d bytes of a fragment from %s " 447 "overlaps the succeeding fragment", 448 i, ip6_sprintf(&q6->ip6q_src)); 449 #endif 450 free(ip6af, M_FTABLE); 451 goto dropfrag; 452 } 453 } 454 #endif 455 456 insert: 457 458 /* 459 * Stick new segment in its place; 460 * check for complete reassembly. 461 * Move to front of packet queue, as we are 462 * the most recently active fragmented packet. 463 */ 464 frag6_enq(ip6af, af6->ip6af_up); 465 frag6_nfrags++; 466 q6->ip6q_nfrag++; 467 #if 0 /* xxx */ 468 if (q6 != ip6q.ip6q_next) { 469 frag6_remque(q6); 470 frag6_insque(q6, &ip6q); 471 } 472 #endif 473 next = 0; 474 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 475 af6 = af6->ip6af_down) { 476 if (af6->ip6af_off != next) { 477 IP6Q_UNLOCK(); 478 return IPPROTO_DONE; 479 } 480 next += af6->ip6af_frglen; 481 } 482 if (af6->ip6af_up->ip6af_mff) { 483 IP6Q_UNLOCK(); 484 return IPPROTO_DONE; 485 } 486 487 /* 488 * Reassembly is complete; concatenate fragments. 489 */ 490 ip6af = q6->ip6q_down; 491 t = m = IP6_REASS_MBUF(ip6af); 492 af6 = ip6af->ip6af_down; 493 frag6_deq(ip6af); 494 while (af6 != (struct ip6asfrag *)q6) { 495 af6dwn = af6->ip6af_down; 496 frag6_deq(af6); 497 while (t->m_next) 498 t = t->m_next; 499 t->m_next = IP6_REASS_MBUF(af6); 500 m_adj(t->m_next, af6->ip6af_offset); 501 free(af6, M_FTABLE); 502 af6 = af6dwn; 503 } 504 505 /* adjust offset to point where the original next header starts */ 506 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 507 free(ip6af, M_FTABLE); 508 ip6 = mtod(m, struct ip6_hdr *); 509 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 510 ip6->ip6_src = q6->ip6q_src; 511 ip6->ip6_dst = q6->ip6q_dst; 512 nxt = q6->ip6q_nxt; 513 #ifdef notyet 514 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 515 #endif 516 517 /* 518 * Delete frag6 header with as a few cost as possible. 519 */ 520 if (offset < m->m_len) { 521 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 522 offset); 523 m->m_data += sizeof(struct ip6_frag); 524 m->m_len -= sizeof(struct ip6_frag); 525 } else { 526 /* this comes with no copy if the boundary is on cluster */ 527 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 528 frag6_remque(q6); 529 frag6_nfrags -= q6->ip6q_nfrag; 530 free(q6, M_FTABLE); 531 frag6_nfragpackets--; 532 goto dropfrag; 533 } 534 m_adj(t, sizeof(struct ip6_frag)); 535 m_cat(m, t); 536 } 537 538 /* 539 * Store NXT to the original. 540 */ 541 { 542 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 543 *prvnxtp = nxt; 544 } 545 546 frag6_remque(q6); 547 frag6_nfrags -= q6->ip6q_nfrag; 548 free(q6, M_FTABLE); 549 frag6_nfragpackets--; 550 551 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 552 int plen = 0; 553 for (t = m; t; t = t->m_next) 554 plen += t->m_len; 555 m->m_pkthdr.len = plen; 556 } 557 558 ip6stat.ip6s_reassembled++; 559 in6_ifstat_inc(dstifp, ifs6_reass_ok); 560 561 /* 562 * Tell launch routine the next header 563 */ 564 565 *mp = m; 566 *offp = offset; 567 568 IP6Q_UNLOCK(); 569 return nxt; 570 571 dropfrag: 572 IP6Q_UNLOCK(); 573 in6_ifstat_inc(dstifp, ifs6_reass_fail); 574 ip6stat.ip6s_fragdropped++; 575 m_freem(m); 576 return IPPROTO_DONE; 577 } 578 579 /* 580 * Free a fragment reassembly header and all 581 * associated datagrams. 582 */ 583 void 584 frag6_freef(q6) 585 struct ip6q *q6; 586 { 587 struct ip6asfrag *af6, *down6; 588 589 IP6Q_LOCK_ASSERT(); 590 591 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 592 af6 = down6) { 593 struct mbuf *m = IP6_REASS_MBUF(af6); 594 595 down6 = af6->ip6af_down; 596 frag6_deq(af6); 597 598 /* 599 * Return ICMP time exceeded error for the 1st fragment. 600 * Just free other fragments. 601 */ 602 if (af6->ip6af_off == 0) { 603 struct ip6_hdr *ip6; 604 605 /* adjust pointer */ 606 ip6 = mtod(m, struct ip6_hdr *); 607 608 /* restore source and destination addresses */ 609 ip6->ip6_src = q6->ip6q_src; 610 ip6->ip6_dst = q6->ip6q_dst; 611 612 icmp6_error(m, ICMP6_TIME_EXCEEDED, 613 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 614 } else 615 m_freem(m); 616 free(af6, M_FTABLE); 617 } 618 frag6_remque(q6); 619 frag6_nfrags -= q6->ip6q_nfrag; 620 free(q6, M_FTABLE); 621 frag6_nfragpackets--; 622 } 623 624 /* 625 * Put an ip fragment on a reassembly chain. 626 * Like insque, but pointers in middle of structure. 627 */ 628 void 629 frag6_enq(af6, up6) 630 struct ip6asfrag *af6, *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(af6) 646 struct ip6asfrag *af6; 647 { 648 649 IP6Q_LOCK_ASSERT(); 650 651 af6->ip6af_up->ip6af_down = af6->ip6af_down; 652 af6->ip6af_down->ip6af_up = af6->ip6af_up; 653 } 654 655 void 656 frag6_insque(new, old) 657 struct ip6q *new, *old; 658 { 659 660 IP6Q_LOCK_ASSERT(); 661 662 new->ip6q_prev = old; 663 new->ip6q_next = old->ip6q_next; 664 old->ip6q_next->ip6q_prev= new; 665 old->ip6q_next = new; 666 } 667 668 void 669 frag6_remque(p6) 670 struct ip6q *p6; 671 { 672 673 IP6Q_LOCK_ASSERT(); 674 675 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 676 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 677 } 678 679 /* 680 * IPv6 reassembling timer processing; 681 * if a timer expires on a reassembly 682 * queue, discard it. 683 */ 684 void 685 frag6_slowtimo() 686 { 687 struct ip6q *q6; 688 689 #if 0 690 GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */ 691 #endif 692 693 IP6Q_LOCK(); 694 q6 = ip6q.ip6q_next; 695 if (q6) 696 while (q6 != &ip6q) { 697 --q6->ip6q_ttl; 698 q6 = q6->ip6q_next; 699 if (q6->ip6q_prev->ip6q_ttl == 0) { 700 ip6stat.ip6s_fragtimeout++; 701 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 702 frag6_freef(q6->ip6q_prev); 703 } 704 } 705 /* 706 * If we are over the maximum number of fragments 707 * (due to the limit being lowered), drain off 708 * enough to get down to the new limit. 709 */ 710 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 711 ip6q.ip6q_prev) { 712 ip6stat.ip6s_fragoverflow++; 713 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 714 frag6_freef(ip6q.ip6q_prev); 715 } 716 IP6Q_UNLOCK(); 717 718 #if 0 719 /* 720 * Routing changes might produce a better route than we last used; 721 * make sure we notice eventually, even if forwarding only for one 722 * destination and the cache is never replaced. 723 */ 724 if (ip6_forward_rt.ro_rt) { 725 RTFREE(ip6_forward_rt.ro_rt); 726 ip6_forward_rt.ro_rt = 0; 727 } 728 if (ipsrcchk_rt.ro_rt) { 729 RTFREE(ipsrcchk_rt.ro_rt); 730 ipsrcchk_rt.ro_rt = 0; 731 } 732 #endif 733 } 734 735 /* 736 * Drain off all datagram fragments. 737 */ 738 void 739 frag6_drain() 740 { 741 742 if (IP6Q_TRYLOCK() == 0) 743 return; 744 while (ip6q.ip6q_next != &ip6q) { 745 ip6stat.ip6s_fragdropped++; 746 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 747 frag6_freef(ip6q.ip6q_next); 748 } 749 IP6Q_UNLOCK(); 750 } 751