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 #include <sys/vimage.h> 47 48 #include <net/if.h> 49 #include <net/route.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_var.h> 53 #include <netinet/ip6.h> 54 #include <netinet6/ip6_var.h> 55 #include <netinet/icmp6.h> 56 #include <netinet/in_systm.h> /* for ECN definitions */ 57 #include <netinet/ip.h> /* for ECN definitions */ 58 59 /* 60 * Define it to get a correct behavior on per-interface statistics. 61 * You will need to perform an extra routing table lookup, per fragment, 62 * to do it. This may, or may not be, a performance hit. 63 */ 64 #define IN6_IFSTAT_STRICT 65 66 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 67 static void frag6_deq(struct ip6asfrag *); 68 static void frag6_insque(struct ip6q *, struct ip6q *); 69 static void frag6_remque(struct ip6q *); 70 static void frag6_freef(struct ip6q *); 71 72 static struct mtx ip6qlock; 73 /* 74 * These fields all protected by ip6qlock. 75 */ 76 static u_int frag6_nfragpackets; 77 static u_int frag6_nfrags; 78 static struct ip6q ip6q; /* ip6 reassemble queue */ 79 80 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 81 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 82 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 83 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 84 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 85 86 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 87 88 /* 89 * Initialise reassembly queue and fragment identifier. 90 */ 91 static void 92 frag6_change(void *tag) 93 { 94 95 V_ip6_maxfragpackets = nmbclusters / 4; 96 V_ip6_maxfrags = nmbclusters / 4; 97 } 98 99 void 100 frag6_init(void) 101 { 102 103 V_ip6_maxfragpackets = nmbclusters / 4; 104 V_ip6_maxfrags = nmbclusters / 4; 105 EVENTHANDLER_REGISTER(nmbclusters_change, 106 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 107 108 IP6Q_LOCK_INIT(); 109 110 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 111 } 112 113 /* 114 * In RFC2460, fragment and reassembly rule do not agree with each other, 115 * in terms of next header field handling in fragment header. 116 * While the sender will use the same value for all of the fragmented packets, 117 * receiver is suggested not to check the consistency. 118 * 119 * fragment rule (p20): 120 * (2) A Fragment header containing: 121 * The Next Header value that identifies the first header of 122 * the Fragmentable Part of the original packet. 123 * -> next header field is same for all fragments 124 * 125 * reassembly rule (p21): 126 * The Next Header field of the last header of the Unfragmentable 127 * Part is obtained from the Next Header field of the first 128 * fragment's Fragment header. 129 * -> should grab it from the first fragment only 130 * 131 * The following note also contradicts with fragment rule - noone is going to 132 * send different fragment with different next header field. 133 * 134 * additional note (p22): 135 * The Next Header values in the Fragment headers of different 136 * fragments of the same original packet may differ. Only the value 137 * from the Offset zero fragment packet is used for reassembly. 138 * -> should grab it from the first fragment only 139 * 140 * There is no explicit reason given in the RFC. Historical reason maybe? 141 */ 142 /* 143 * Fragment input 144 */ 145 int 146 frag6_input(struct mbuf **mp, int *offp, int proto) 147 { 148 struct mbuf *m = *mp, *t; 149 struct ip6_hdr *ip6; 150 struct ip6_frag *ip6f; 151 struct ip6q *q6; 152 struct ip6asfrag *af6, *ip6af, *af6dwn; 153 #ifdef IN6_IFSTAT_STRICT 154 struct in6_ifaddr *ia; 155 #endif 156 int offset = *offp, nxt, i, next; 157 int first_frag = 0; 158 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 159 struct ifnet *dstifp; 160 u_int8_t ecn, ecn0; 161 #if 0 162 char ip6buf[INET6_ADDRSTRLEN]; 163 #endif 164 165 ip6 = mtod(m, struct ip6_hdr *); 166 #ifndef PULLDOWN_TEST 167 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 168 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 169 #else 170 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 171 if (ip6f == NULL) 172 return (IPPROTO_DONE); 173 #endif 174 175 dstifp = NULL; 176 #ifdef IN6_IFSTAT_STRICT 177 /* find the destination interface of the packet. */ 178 if ((ia = ip6_getdstifaddr(m)) != NULL) 179 dstifp = ia->ia_ifp; 180 #else 181 /* we are violating the spec, this is not the destination interface */ 182 if ((m->m_flags & M_PKTHDR) != 0) 183 dstifp = m->m_pkthdr.rcvif; 184 #endif 185 186 /* jumbo payload can't contain a fragment header */ 187 if (ip6->ip6_plen == 0) { 188 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 189 in6_ifstat_inc(dstifp, ifs6_reass_fail); 190 return IPPROTO_DONE; 191 } 192 193 /* 194 * check whether fragment packet's fragment length is 195 * multiple of 8 octets. 196 * sizeof(struct ip6_frag) == 8 197 * sizeof(struct ip6_hdr) = 40 198 */ 199 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 200 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 201 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 202 offsetof(struct ip6_hdr, ip6_plen)); 203 in6_ifstat_inc(dstifp, ifs6_reass_fail); 204 return IPPROTO_DONE; 205 } 206 207 V_ip6stat.ip6s_fragments++; 208 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 209 210 /* offset now points to data portion */ 211 offset += sizeof(struct ip6_frag); 212 213 IP6Q_LOCK(); 214 215 /* 216 * Enforce upper bound on number of fragments. 217 * If maxfrag is 0, never accept fragments. 218 * If maxfrag is -1, accept all fragments without limitation. 219 */ 220 if (V_ip6_maxfrags < 0) 221 ; 222 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 223 goto dropfrag; 224 225 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 226 if (ip6f->ip6f_ident == q6->ip6q_ident && 227 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 228 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 229 break; 230 231 if (q6 == &V_ip6q) { 232 /* 233 * the first fragment to arrive, create a reassembly queue. 234 */ 235 first_frag = 1; 236 237 /* 238 * Enforce upper bound on number of fragmented packets 239 * for which we attempt reassembly; 240 * If maxfragpackets is 0, never accept fragments. 241 * If maxfragpackets is -1, accept all fragments without 242 * limitation. 243 */ 244 if (V_ip6_maxfragpackets < 0) 245 ; 246 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 247 goto dropfrag; 248 V_frag6_nfragpackets++; 249 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 250 M_NOWAIT); 251 if (q6 == NULL) 252 goto dropfrag; 253 bzero(q6, sizeof(*q6)); 254 255 frag6_insque(q6, &V_ip6q); 256 257 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 258 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 259 #ifdef notyet 260 q6->ip6q_nxtp = (u_char *)nxtp; 261 #endif 262 q6->ip6q_ident = ip6f->ip6f_ident; 263 q6->ip6q_ttl = IPV6_FRAGTTL; 264 q6->ip6q_src = ip6->ip6_src; 265 q6->ip6q_dst = ip6->ip6_dst; 266 q6->ip6q_ecn = 267 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 268 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 269 270 q6->ip6q_nfrag = 0; 271 } 272 273 /* 274 * If it's the 1st fragment, record the length of the 275 * unfragmentable part and the next header of the fragment header. 276 */ 277 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 278 if (fragoff == 0) { 279 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 280 sizeof(struct ip6_frag); 281 q6->ip6q_nxt = ip6f->ip6f_nxt; 282 } 283 284 /* 285 * Check that the reassembled packet would not exceed 65535 bytes 286 * in size. 287 * If it would exceed, discard the fragment and return an ICMP error. 288 */ 289 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 290 if (q6->ip6q_unfrglen >= 0) { 291 /* The 1st fragment has already arrived. */ 292 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 293 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 294 offset - sizeof(struct ip6_frag) + 295 offsetof(struct ip6_frag, ip6f_offlg)); 296 IP6Q_UNLOCK(); 297 return (IPPROTO_DONE); 298 } 299 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 300 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 301 offset - sizeof(struct ip6_frag) + 302 offsetof(struct ip6_frag, ip6f_offlg)); 303 IP6Q_UNLOCK(); 304 return (IPPROTO_DONE); 305 } 306 /* 307 * If it's the first fragment, do the above check for each 308 * fragment already stored in the reassembly queue. 309 */ 310 if (fragoff == 0) { 311 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 312 af6 = af6dwn) { 313 af6dwn = af6->ip6af_down; 314 315 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 316 IPV6_MAXPACKET) { 317 struct mbuf *merr = IP6_REASS_MBUF(af6); 318 struct ip6_hdr *ip6err; 319 int erroff = af6->ip6af_offset; 320 321 /* dequeue the fragment. */ 322 frag6_deq(af6); 323 free(af6, M_FTABLE); 324 325 /* adjust pointer. */ 326 ip6err = mtod(merr, struct ip6_hdr *); 327 328 /* 329 * Restore source and destination addresses 330 * in the erroneous IPv6 header. 331 */ 332 ip6err->ip6_src = q6->ip6q_src; 333 ip6err->ip6_dst = q6->ip6q_dst; 334 335 icmp6_error(merr, ICMP6_PARAM_PROB, 336 ICMP6_PARAMPROB_HEADER, 337 erroff - sizeof(struct ip6_frag) + 338 offsetof(struct ip6_frag, ip6f_offlg)); 339 } 340 } 341 } 342 343 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 344 M_NOWAIT); 345 if (ip6af == NULL) 346 goto dropfrag; 347 bzero(ip6af, sizeof(*ip6af)); 348 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 349 ip6af->ip6af_off = fragoff; 350 ip6af->ip6af_frglen = frgpartlen; 351 ip6af->ip6af_offset = offset; 352 IP6_REASS_MBUF(ip6af) = m; 353 354 if (first_frag) { 355 af6 = (struct ip6asfrag *)q6; 356 goto insert; 357 } 358 359 /* 360 * Handle ECN by comparing this segment with the first one; 361 * if CE is set, do not lose CE. 362 * drop if CE and not-ECT are mixed for the same packet. 363 */ 364 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 365 ecn0 = q6->ip6q_ecn; 366 if (ecn == IPTOS_ECN_CE) { 367 if (ecn0 == IPTOS_ECN_NOTECT) { 368 free(ip6af, M_FTABLE); 369 goto dropfrag; 370 } 371 if (ecn0 != IPTOS_ECN_CE) 372 q6->ip6q_ecn = IPTOS_ECN_CE; 373 } 374 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 375 free(ip6af, M_FTABLE); 376 goto dropfrag; 377 } 378 379 /* 380 * Find a segment which begins after this one does. 381 */ 382 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 383 af6 = af6->ip6af_down) 384 if (af6->ip6af_off > ip6af->ip6af_off) 385 break; 386 387 #if 0 388 /* 389 * If there is a preceding segment, it may provide some of 390 * our data already. If so, drop the data from the incoming 391 * segment. If it provides all of our data, drop us. 392 */ 393 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 394 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 395 - ip6af->ip6af_off; 396 if (i > 0) { 397 if (i >= ip6af->ip6af_frglen) 398 goto dropfrag; 399 m_adj(IP6_REASS_MBUF(ip6af), i); 400 ip6af->ip6af_off += i; 401 ip6af->ip6af_frglen -= i; 402 } 403 } 404 405 /* 406 * While we overlap succeeding segments trim them or, 407 * if they are completely covered, dequeue them. 408 */ 409 while (af6 != (struct ip6asfrag *)q6 && 410 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 411 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 412 if (i < af6->ip6af_frglen) { 413 af6->ip6af_frglen -= i; 414 af6->ip6af_off += i; 415 m_adj(IP6_REASS_MBUF(af6), i); 416 break; 417 } 418 af6 = af6->ip6af_down; 419 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 420 frag6_deq(af6->ip6af_up); 421 } 422 #else 423 /* 424 * If the incoming framgent overlaps some existing fragments in 425 * the reassembly queue, drop it, since it is dangerous to override 426 * existing fragments from a security point of view. 427 * We don't know which fragment is the bad guy - here we trust 428 * fragment that came in earlier, with no real reason. 429 * 430 * Note: due to changes after disabling this part, mbuf passed to 431 * m_adj() below now does not meet the requirement. 432 */ 433 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 434 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 435 - ip6af->ip6af_off; 436 if (i > 0) { 437 #if 0 /* suppress the noisy log */ 438 log(LOG_ERR, "%d bytes of a fragment from %s " 439 "overlaps the previous fragment\n", 440 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 441 #endif 442 free(ip6af, M_FTABLE); 443 goto dropfrag; 444 } 445 } 446 if (af6 != (struct ip6asfrag *)q6) { 447 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 448 if (i > 0) { 449 #if 0 /* suppress the noisy log */ 450 log(LOG_ERR, "%d bytes of a fragment from %s " 451 "overlaps the succeeding fragment", 452 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 453 #endif 454 free(ip6af, M_FTABLE); 455 goto dropfrag; 456 } 457 } 458 #endif 459 460 insert: 461 462 /* 463 * Stick new segment in its place; 464 * check for complete reassembly. 465 * Move to front of packet queue, as we are 466 * the most recently active fragmented packet. 467 */ 468 frag6_enq(ip6af, af6->ip6af_up); 469 V_frag6_nfrags++; 470 q6->ip6q_nfrag++; 471 #if 0 /* xxx */ 472 if (q6 != V_ip6q.ip6q_next) { 473 frag6_remque(q6); 474 frag6_insque(q6, &V_ip6q); 475 } 476 #endif 477 next = 0; 478 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 479 af6 = af6->ip6af_down) { 480 if (af6->ip6af_off != next) { 481 IP6Q_UNLOCK(); 482 return IPPROTO_DONE; 483 } 484 next += af6->ip6af_frglen; 485 } 486 if (af6->ip6af_up->ip6af_mff) { 487 IP6Q_UNLOCK(); 488 return IPPROTO_DONE; 489 } 490 491 /* 492 * Reassembly is complete; concatenate fragments. 493 */ 494 ip6af = q6->ip6q_down; 495 t = m = IP6_REASS_MBUF(ip6af); 496 af6 = ip6af->ip6af_down; 497 frag6_deq(ip6af); 498 while (af6 != (struct ip6asfrag *)q6) { 499 af6dwn = af6->ip6af_down; 500 frag6_deq(af6); 501 while (t->m_next) 502 t = t->m_next; 503 t->m_next = IP6_REASS_MBUF(af6); 504 m_adj(t->m_next, af6->ip6af_offset); 505 free(af6, M_FTABLE); 506 af6 = af6dwn; 507 } 508 509 /* adjust offset to point where the original next header starts */ 510 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 511 free(ip6af, M_FTABLE); 512 ip6 = mtod(m, struct ip6_hdr *); 513 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 514 if (q6->ip6q_ecn == IPTOS_ECN_CE) 515 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 516 nxt = q6->ip6q_nxt; 517 #ifdef notyet 518 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 519 #endif 520 521 /* Delete frag6 header */ 522 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 523 /* This is the only possible case with !PULLDOWN_TEST */ 524 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 525 offset); 526 m->m_data += sizeof(struct ip6_frag); 527 m->m_len -= sizeof(struct ip6_frag); 528 } else { 529 /* this comes with no copy if the boundary is on cluster */ 530 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 531 frag6_remque(q6); 532 V_frag6_nfrags -= q6->ip6q_nfrag; 533 free(q6, M_FTABLE); 534 V_frag6_nfragpackets--; 535 goto dropfrag; 536 } 537 m_adj(t, sizeof(struct ip6_frag)); 538 m_cat(m, t); 539 } 540 541 /* 542 * Store NXT to the original. 543 */ 544 { 545 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 546 *prvnxtp = nxt; 547 } 548 549 frag6_remque(q6); 550 V_frag6_nfrags -= q6->ip6q_nfrag; 551 free(q6, M_FTABLE); 552 V_frag6_nfragpackets--; 553 554 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 555 int plen = 0; 556 for (t = m; t; t = t->m_next) 557 plen += t->m_len; 558 m->m_pkthdr.len = plen; 559 } 560 561 V_ip6stat.ip6s_reassembled++; 562 in6_ifstat_inc(dstifp, ifs6_reass_ok); 563 564 /* 565 * Tell launch routine the next header 566 */ 567 568 *mp = m; 569 *offp = offset; 570 571 IP6Q_UNLOCK(); 572 return nxt; 573 574 dropfrag: 575 IP6Q_UNLOCK(); 576 in6_ifstat_inc(dstifp, ifs6_reass_fail); 577 V_ip6stat.ip6s_fragdropped++; 578 m_freem(m); 579 return IPPROTO_DONE; 580 } 581 582 /* 583 * Free a fragment reassembly header and all 584 * associated datagrams. 585 */ 586 void 587 frag6_freef(struct ip6q *q6) 588 { 589 struct ip6asfrag *af6, *down6; 590 591 IP6Q_LOCK_ASSERT(); 592 593 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 594 af6 = down6) { 595 struct mbuf *m = IP6_REASS_MBUF(af6); 596 597 down6 = af6->ip6af_down; 598 frag6_deq(af6); 599 600 /* 601 * Return ICMP time exceeded error for the 1st fragment. 602 * Just free other fragments. 603 */ 604 if (af6->ip6af_off == 0) { 605 struct ip6_hdr *ip6; 606 607 /* adjust pointer */ 608 ip6 = mtod(m, struct ip6_hdr *); 609 610 /* restore source and destination addresses */ 611 ip6->ip6_src = q6->ip6q_src; 612 ip6->ip6_dst = q6->ip6q_dst; 613 614 icmp6_error(m, ICMP6_TIME_EXCEEDED, 615 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 616 } else 617 m_freem(m); 618 free(af6, M_FTABLE); 619 } 620 frag6_remque(q6); 621 V_frag6_nfrags -= q6->ip6q_nfrag; 622 free(q6, M_FTABLE); 623 V_frag6_nfragpackets--; 624 } 625 626 /* 627 * Put an ip fragment on a reassembly chain. 628 * Like insque, but pointers in middle of structure. 629 */ 630 void 631 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 632 { 633 634 IP6Q_LOCK_ASSERT(); 635 636 af6->ip6af_up = up6; 637 af6->ip6af_down = up6->ip6af_down; 638 up6->ip6af_down->ip6af_up = af6; 639 up6->ip6af_down = af6; 640 } 641 642 /* 643 * To frag6_enq as remque is to insque. 644 */ 645 void 646 frag6_deq(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(struct ip6q *new, struct ip6q *old) 657 { 658 659 IP6Q_LOCK_ASSERT(); 660 661 new->ip6q_prev = old; 662 new->ip6q_next = old->ip6q_next; 663 old->ip6q_next->ip6q_prev= new; 664 old->ip6q_next = new; 665 } 666 667 void 668 frag6_remque(struct ip6q *p6) 669 { 670 671 IP6Q_LOCK_ASSERT(); 672 673 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 674 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 675 } 676 677 /* 678 * IPv6 reassembling timer processing; 679 * if a timer expires on a reassembly 680 * queue, discard it. 681 */ 682 void 683 frag6_slowtimo(void) 684 { 685 struct ip6q *q6; 686 687 IP6Q_LOCK(); 688 q6 = V_ip6q.ip6q_next; 689 if (q6) 690 while (q6 != &V_ip6q) { 691 --q6->ip6q_ttl; 692 q6 = q6->ip6q_next; 693 if (q6->ip6q_prev->ip6q_ttl == 0) { 694 V_ip6stat.ip6s_fragtimeout++; 695 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 696 frag6_freef(q6->ip6q_prev); 697 } 698 } 699 /* 700 * If we are over the maximum number of fragments 701 * (due to the limit being lowered), drain off 702 * enough to get down to the new limit. 703 */ 704 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 705 V_ip6q.ip6q_prev) { 706 V_ip6stat.ip6s_fragoverflow++; 707 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 708 frag6_freef(V_ip6q.ip6q_prev); 709 } 710 IP6Q_UNLOCK(); 711 712 #if 0 713 /* 714 * Routing changes might produce a better route than we last used; 715 * make sure we notice eventually, even if forwarding only for one 716 * destination and the cache is never replaced. 717 */ 718 if (V_ip6_forward_rt.ro_rt) { 719 RTFREE(V_ip6_forward_rt.ro_rt); 720 V_ip6_forward_rt.ro_rt = 0; 721 } 722 if (ipsrcchk_rt.ro_rt) { 723 RTFREE(ipsrcchk_rt.ro_rt); 724 ipsrcchk_rt.ro_rt = 0; 725 } 726 #endif 727 } 728 729 /* 730 * Drain off all datagram fragments. 731 */ 732 void 733 frag6_drain(void) 734 { 735 736 if (IP6Q_TRYLOCK() == 0) 737 return; 738 while (V_ip6q.ip6q_next != &V_ip6q) { 739 V_ip6stat.ip6s_fragdropped++; 740 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 741 frag6_freef(V_ip6q.ip6q_next); 742 } 743 IP6Q_UNLOCK(); 744 } 745