Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet6/frag6.c
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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 #include <net/net_osdep.h> 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 __P((struct ip6asfrag *, struct ip6asfrag *)); 66 static void frag6_deq __P((struct ip6asfrag *)); 67 static void frag6_insque __P((struct ip6q *, struct ip6q *)); 68 static void frag6_remque __P((struct ip6q *)); 69 static void frag6_freef __P((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 void 91 frag6_init() 92 { 93 94 ip6_maxfragpackets = nmbclusters / 4; 95 ip6_maxfrags = nmbclusters / 4; 96 97 IP6Q_LOCK_INIT(); 98 99 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 100 } 101 102 /* 103 * In RFC2460, fragment and reassembly rule do not agree with each other, 104 * in terms of next header field handling in fragment header. 105 * While the sender will use the same value for all of the fragmented packets, 106 * receiver is suggested not to check the consistency. 107 * 108 * fragment rule (p20): 109 * (2) A Fragment header containing: 110 * The Next Header value that identifies the first header of 111 * the Fragmentable Part of the original packet. 112 * -> next header field is same for all fragments 113 * 114 * reassembly rule (p21): 115 * The Next Header field of the last header of the Unfragmentable 116 * Part is obtained from the Next Header field of the first 117 * fragment's Fragment header. 118 * -> should grab it from the first fragment only 119 * 120 * The following note also contradicts with fragment rule - noone is going to 121 * send different fragment with different next header field. 122 * 123 * additional note (p22): 124 * The Next Header values in the Fragment headers of different 125 * fragments of the same original packet may differ. Only the value 126 * from the Offset zero fragment packet is used for reassembly. 127 * -> should grab it from the first fragment only 128 * 129 * There is no explicit reason given in the RFC. Historical reason maybe? 130 */ 131 /* 132 * Fragment input 133 */ 134 int 135 frag6_input(mp, offp, proto) 136 struct mbuf **mp; 137 int *offp, proto; 138 { 139 struct mbuf *m = *mp, *t; 140 struct ip6_hdr *ip6; 141 struct ip6_frag *ip6f; 142 struct ip6q *q6; 143 struct ip6asfrag *af6, *ip6af, *af6dwn; 144 #ifdef IN6_IFSTAT_STRICT 145 struct in6_ifaddr *ia; 146 #endif 147 int offset = *offp, nxt, i, next; 148 int first_frag = 0; 149 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 150 struct ifnet *dstifp; 151 u_int8_t ecn, ecn0; 152 153 ip6 = mtod(m, struct ip6_hdr *); 154 #ifndef PULLDOWN_TEST 155 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 156 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 157 #else 158 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 159 if (ip6f == NULL) 160 return (IPPROTO_DONE); 161 #endif 162 163 dstifp = NULL; 164 #ifdef IN6_IFSTAT_STRICT 165 /* find the destination interface of the packet. */ 166 if ((ia = ip6_getdstifaddr(m)) != NULL) 167 dstifp = ia->ia_ifp; 168 #else 169 /* we are violating the spec, this is not the destination interface */ 170 if ((m->m_flags & M_PKTHDR) != 0) 171 dstifp = m->m_pkthdr.rcvif; 172 #endif 173 174 /* jumbo payload can't contain a fragment header */ 175 if (ip6->ip6_plen == 0) { 176 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 177 in6_ifstat_inc(dstifp, ifs6_reass_fail); 178 return IPPROTO_DONE; 179 } 180 181 /* 182 * check whether fragment packet's fragment length is 183 * multiple of 8 octets. 184 * sizeof(struct ip6_frag) == 8 185 * sizeof(struct ip6_hdr) = 40 186 */ 187 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 188 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 189 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 190 offsetof(struct ip6_hdr, ip6_plen)); 191 in6_ifstat_inc(dstifp, ifs6_reass_fail); 192 return IPPROTO_DONE; 193 } 194 195 ip6stat.ip6s_fragments++; 196 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 197 198 /* offset now points to data portion */ 199 offset += sizeof(struct ip6_frag); 200 201 IP6Q_LOCK(); 202 203 /* 204 * Enforce upper bound on number of fragments. 205 * If maxfrag is 0, never accept fragments. 206 * If maxfrag is -1, accept all fragments without limitation. 207 */ 208 if (ip6_maxfrags < 0) 209 ; 210 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 211 goto dropfrag; 212 213 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 214 if (ip6f->ip6f_ident == q6->ip6q_ident && 215 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 216 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 217 break; 218 219 if (q6 == &ip6q) { 220 /* 221 * the first fragment to arrive, create a reassembly queue. 222 */ 223 first_frag = 1; 224 225 /* 226 * Enforce upper bound on number of fragmented packets 227 * for which we attempt reassembly; 228 * If maxfragpackets is 0, never accept fragments. 229 * If maxfragpackets is -1, accept all fragments without 230 * limitation. 231 */ 232 if (ip6_maxfragpackets < 0) 233 ; 234 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 235 goto dropfrag; 236 frag6_nfragpackets++; 237 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 238 M_NOWAIT); 239 if (q6 == NULL) 240 goto dropfrag; 241 bzero(q6, sizeof(*q6)); 242 243 frag6_insque(q6, &ip6q); 244 245 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 246 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 247 #ifdef notyet 248 q6->ip6q_nxtp = (u_char *)nxtp; 249 #endif 250 q6->ip6q_ident = ip6f->ip6f_ident; 251 q6->ip6q_ttl = IPV6_FRAGTTL; 252 q6->ip6q_src = ip6->ip6_src; 253 q6->ip6q_dst = ip6->ip6_dst; 254 q6->ip6q_ecn = 255 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 256 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 257 258 q6->ip6q_nfrag = 0; 259 } 260 261 /* 262 * If it's the 1st fragment, record the length of the 263 * unfragmentable part and the next header of the fragment header. 264 */ 265 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 266 if (fragoff == 0) { 267 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 268 sizeof(struct ip6_frag); 269 q6->ip6q_nxt = ip6f->ip6f_nxt; 270 } 271 272 /* 273 * Check that the reassembled packet would not exceed 65535 bytes 274 * in size. 275 * If it would exceed, discard the fragment and return an ICMP error. 276 */ 277 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 278 if (q6->ip6q_unfrglen >= 0) { 279 /* The 1st fragment has already arrived. */ 280 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 281 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 282 offset - sizeof(struct ip6_frag) + 283 offsetof(struct ip6_frag, ip6f_offlg)); 284 IP6Q_UNLOCK(); 285 return (IPPROTO_DONE); 286 } 287 } else if (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 /* 295 * If it's the first fragment, do the above check for each 296 * fragment already stored in the reassembly queue. 297 */ 298 if (fragoff == 0) { 299 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 300 af6 = af6dwn) { 301 af6dwn = af6->ip6af_down; 302 303 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 304 IPV6_MAXPACKET) { 305 struct mbuf *merr = IP6_REASS_MBUF(af6); 306 struct ip6_hdr *ip6err; 307 int erroff = af6->ip6af_offset; 308 309 /* dequeue the fragment. */ 310 frag6_deq(af6); 311 free(af6, M_FTABLE); 312 313 /* adjust pointer. */ 314 ip6err = mtod(merr, struct ip6_hdr *); 315 316 /* 317 * Restore source and destination addresses 318 * in the erroneous IPv6 header. 319 */ 320 ip6err->ip6_src = q6->ip6q_src; 321 ip6err->ip6_dst = q6->ip6q_dst; 322 323 icmp6_error(merr, ICMP6_PARAM_PROB, 324 ICMP6_PARAMPROB_HEADER, 325 erroff - sizeof(struct ip6_frag) + 326 offsetof(struct ip6_frag, ip6f_offlg)); 327 } 328 } 329 } 330 331 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 332 M_NOWAIT); 333 if (ip6af == NULL) 334 goto dropfrag; 335 bzero(ip6af, sizeof(*ip6af)); 336 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 337 ip6af->ip6af_off = fragoff; 338 ip6af->ip6af_frglen = frgpartlen; 339 ip6af->ip6af_offset = offset; 340 IP6_REASS_MBUF(ip6af) = m; 341 342 if (first_frag) { 343 af6 = (struct ip6asfrag *)q6; 344 goto insert; 345 } 346 347 /* 348 * Handle ECN by comparing this segment with the first one; 349 * if CE is set, do not lose CE. 350 * drop if CE and not-ECT are mixed for the same packet. 351 */ 352 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 353 ecn0 = q6->ip6q_ecn; 354 if (ecn == IPTOS_ECN_CE) { 355 if (ecn0 == IPTOS_ECN_NOTECT) { 356 free(ip6af, M_FTABLE); 357 goto dropfrag; 358 } 359 if (ecn0 != IPTOS_ECN_CE) 360 q6->ip6q_ecn = IPTOS_ECN_CE; 361 } 362 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 363 free(ip6af, M_FTABLE); 364 goto dropfrag; 365 } 366 367 /* 368 * Find a segment which begins after this one does. 369 */ 370 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 371 af6 = af6->ip6af_down) 372 if (af6->ip6af_off > ip6af->ip6af_off) 373 break; 374 375 #if 0 376 /* 377 * If there is a preceding segment, it may provide some of 378 * our data already. If so, drop the data from the incoming 379 * segment. If it provides all of our data, drop us. 380 */ 381 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 382 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 383 - ip6af->ip6af_off; 384 if (i > 0) { 385 if (i >= ip6af->ip6af_frglen) 386 goto dropfrag; 387 m_adj(IP6_REASS_MBUF(ip6af), i); 388 ip6af->ip6af_off += i; 389 ip6af->ip6af_frglen -= i; 390 } 391 } 392 393 /* 394 * While we overlap succeeding segments trim them or, 395 * if they are completely covered, dequeue them. 396 */ 397 while (af6 != (struct ip6asfrag *)q6 && 398 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 399 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 400 if (i < af6->ip6af_frglen) { 401 af6->ip6af_frglen -= i; 402 af6->ip6af_off += i; 403 m_adj(IP6_REASS_MBUF(af6), i); 404 break; 405 } 406 af6 = af6->ip6af_down; 407 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 408 frag6_deq(af6->ip6af_up); 409 } 410 #else 411 /* 412 * If the incoming framgent overlaps some existing fragments in 413 * the reassembly queue, drop it, since it is dangerous to override 414 * existing fragments from a security point of view. 415 * We don't know which fragment is the bad guy - here we trust 416 * fragment that came in earlier, with no real reason. 417 * 418 * Note: due to changes after disabling this part, mbuf passed to 419 * m_adj() below now does not meet the requirement. 420 */ 421 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 422 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 423 - ip6af->ip6af_off; 424 if (i > 0) { 425 #if 0 /* suppress the noisy log */ 426 log(LOG_ERR, "%d bytes of a fragment from %s " 427 "overlaps the previous fragment\n", 428 i, ip6_sprintf(&q6->ip6q_src)); 429 #endif 430 free(ip6af, M_FTABLE); 431 goto dropfrag; 432 } 433 } 434 if (af6 != (struct ip6asfrag *)q6) { 435 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->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 succeeding fragment", 440 i, ip6_sprintf(&q6->ip6q_src)); 441 #endif 442 free(ip6af, M_FTABLE); 443 goto dropfrag; 444 } 445 } 446 #endif 447 448 insert: 449 450 /* 451 * Stick new segment in its place; 452 * check for complete reassembly. 453 * Move to front of packet queue, as we are 454 * the most recently active fragmented packet. 455 */ 456 frag6_enq(ip6af, af6->ip6af_up); 457 frag6_nfrags++; 458 q6->ip6q_nfrag++; 459 #if 0 /* xxx */ 460 if (q6 != ip6q.ip6q_next) { 461 frag6_remque(q6); 462 frag6_insque(q6, &ip6q); 463 } 464 #endif 465 next = 0; 466 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 467 af6 = af6->ip6af_down) { 468 if (af6->ip6af_off != next) { 469 IP6Q_UNLOCK(); 470 return IPPROTO_DONE; 471 } 472 next += af6->ip6af_frglen; 473 } 474 if (af6->ip6af_up->ip6af_mff) { 475 IP6Q_UNLOCK(); 476 return IPPROTO_DONE; 477 } 478 479 /* 480 * Reassembly is complete; concatenate fragments. 481 */ 482 ip6af = q6->ip6q_down; 483 t = m = IP6_REASS_MBUF(ip6af); 484 af6 = ip6af->ip6af_down; 485 frag6_deq(ip6af); 486 while (af6 != (struct ip6asfrag *)q6) { 487 af6dwn = af6->ip6af_down; 488 frag6_deq(af6); 489 while (t->m_next) 490 t = t->m_next; 491 t->m_next = IP6_REASS_MBUF(af6); 492 m_adj(t->m_next, af6->ip6af_offset); 493 free(af6, M_FTABLE); 494 af6 = af6dwn; 495 } 496 497 /* adjust offset to point where the original next header starts */ 498 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 499 free(ip6af, M_FTABLE); 500 ip6 = mtod(m, struct ip6_hdr *); 501 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 502 if (q6->ip6q_ecn == IPTOS_ECN_CE) 503 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 504 nxt = q6->ip6q_nxt; 505 #ifdef notyet 506 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 507 #endif 508 509 /* Delete frag6 header */ 510 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 511 /* This is the only possible case with !PULLDOWN_TEST */ 512 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 513 offset); 514 m->m_data += sizeof(struct ip6_frag); 515 m->m_len -= sizeof(struct ip6_frag); 516 } else { 517 /* this comes with no copy if the boundary is on cluster */ 518 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 519 frag6_remque(q6); 520 frag6_nfrags -= q6->ip6q_nfrag; 521 free(q6, M_FTABLE); 522 frag6_nfragpackets--; 523 goto dropfrag; 524 } 525 m_adj(t, sizeof(struct ip6_frag)); 526 m_cat(m, t); 527 } 528 529 /* 530 * Store NXT to the original. 531 */ 532 { 533 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 534 *prvnxtp = nxt; 535 } 536 537 frag6_remque(q6); 538 frag6_nfrags -= q6->ip6q_nfrag; 539 free(q6, M_FTABLE); 540 frag6_nfragpackets--; 541 542 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 543 int plen = 0; 544 for (t = m; t; t = t->m_next) 545 plen += t->m_len; 546 m->m_pkthdr.len = plen; 547 } 548 549 ip6stat.ip6s_reassembled++; 550 in6_ifstat_inc(dstifp, ifs6_reass_ok); 551 552 /* 553 * Tell launch routine the next header 554 */ 555 556 *mp = m; 557 *offp = offset; 558 559 IP6Q_UNLOCK(); 560 return nxt; 561 562 dropfrag: 563 IP6Q_UNLOCK(); 564 in6_ifstat_inc(dstifp, ifs6_reass_fail); 565 ip6stat.ip6s_fragdropped++; 566 m_freem(m); 567 return IPPROTO_DONE; 568 } 569 570 /* 571 * Free a fragment reassembly header and all 572 * associated datagrams. 573 */ 574 void 575 frag6_freef(q6) 576 struct ip6q *q6; 577 { 578 struct ip6asfrag *af6, *down6; 579 580 IP6Q_LOCK_ASSERT(); 581 582 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 583 af6 = down6) { 584 struct mbuf *m = IP6_REASS_MBUF(af6); 585 586 down6 = af6->ip6af_down; 587 frag6_deq(af6); 588 589 /* 590 * Return ICMP time exceeded error for the 1st fragment. 591 * Just free other fragments. 592 */ 593 if (af6->ip6af_off == 0) { 594 struct ip6_hdr *ip6; 595 596 /* adjust pointer */ 597 ip6 = mtod(m, struct ip6_hdr *); 598 599 /* restore source and destination addresses */ 600 ip6->ip6_src = q6->ip6q_src; 601 ip6->ip6_dst = q6->ip6q_dst; 602 603 icmp6_error(m, ICMP6_TIME_EXCEEDED, 604 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 605 } else 606 m_freem(m); 607 free(af6, M_FTABLE); 608 } 609 frag6_remque(q6); 610 frag6_nfrags -= q6->ip6q_nfrag; 611 free(q6, M_FTABLE); 612 frag6_nfragpackets--; 613 } 614 615 /* 616 * Put an ip fragment on a reassembly chain. 617 * Like insque, but pointers in middle of structure. 618 */ 619 void 620 frag6_enq(af6, up6) 621 struct ip6asfrag *af6, *up6; 622 { 623 624 IP6Q_LOCK_ASSERT(); 625 626 af6->ip6af_up = up6; 627 af6->ip6af_down = up6->ip6af_down; 628 up6->ip6af_down->ip6af_up = af6; 629 up6->ip6af_down = af6; 630 } 631 632 /* 633 * To frag6_enq as remque is to insque. 634 */ 635 void 636 frag6_deq(af6) 637 struct ip6asfrag *af6; 638 { 639 640 IP6Q_LOCK_ASSERT(); 641 642 af6->ip6af_up->ip6af_down = af6->ip6af_down; 643 af6->ip6af_down->ip6af_up = af6->ip6af_up; 644 } 645 646 void 647 frag6_insque(new, old) 648 struct ip6q *new, *old; 649 { 650 651 IP6Q_LOCK_ASSERT(); 652 653 new->ip6q_prev = old; 654 new->ip6q_next = old->ip6q_next; 655 old->ip6q_next->ip6q_prev= new; 656 old->ip6q_next = new; 657 } 658 659 void 660 frag6_remque(p6) 661 struct ip6q *p6; 662 { 663 664 IP6Q_LOCK_ASSERT(); 665 666 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 667 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 668 } 669 670 /* 671 * IPv6 reassembling timer processing; 672 * if a timer expires on a reassembly 673 * queue, discard it. 674 */ 675 void 676 frag6_slowtimo() 677 { 678 struct ip6q *q6; 679 int s = splnet(); 680 681 IP6Q_LOCK(); 682 q6 = ip6q.ip6q_next; 683 if (q6) 684 while (q6 != &ip6q) { 685 --q6->ip6q_ttl; 686 q6 = q6->ip6q_next; 687 if (q6->ip6q_prev->ip6q_ttl == 0) { 688 ip6stat.ip6s_fragtimeout++; 689 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 690 frag6_freef(q6->ip6q_prev); 691 } 692 } 693 /* 694 * If we are over the maximum number of fragments 695 * (due to the limit being lowered), drain off 696 * enough to get down to the new limit. 697 */ 698 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 699 ip6q.ip6q_prev) { 700 ip6stat.ip6s_fragoverflow++; 701 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 702 frag6_freef(ip6q.ip6q_prev); 703 } 704 IP6Q_UNLOCK(); 705 706 #if 0 707 /* 708 * Routing changes might produce a better route than we last used; 709 * make sure we notice eventually, even if forwarding only for one 710 * destination and the cache is never replaced. 711 */ 712 if (ip6_forward_rt.ro_rt) { 713 RTFREE(ip6_forward_rt.ro_rt); 714 ip6_forward_rt.ro_rt = 0; 715 } 716 if (ipsrcchk_rt.ro_rt) { 717 RTFREE(ipsrcchk_rt.ro_rt); 718 ipsrcchk_rt.ro_rt = 0; 719 } 720 #endif 721 722 splx(s); 723 } 724 725 /* 726 * Drain off all datagram fragments. 727 */ 728 void 729 frag6_drain() 730 { 731 732 if (IP6Q_TRYLOCK() == 0) 733 return; 734 while (ip6q.ip6q_next != &ip6q) { 735 ip6stat.ip6s_fragdropped++; 736 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 737 frag6_freef(ip6q.ip6q_next); 738 } 739 IP6Q_UNLOCK(); 740 }
Cache object: 73e354f6b2e4519ea5e1638a7cf631e3
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