Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/netinet6/frag6.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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(void) 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(struct mbuf **mp, int *offp, int proto) 144 { 145 struct mbuf *m = *mp, *t; 146 struct ip6_hdr *ip6; 147 struct ip6_frag *ip6f; 148 struct ip6q *q6; 149 struct ip6asfrag *af6, *ip6af, *af6dwn; 150 #ifdef IN6_IFSTAT_STRICT 151 struct in6_ifaddr *ia; 152 #endif 153 int offset = *offp, nxt, i, next; 154 int first_frag = 0; 155 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 156 struct ifnet *dstifp; 157 u_int8_t ecn, ecn0; 158 #if 0 159 char ip6buf[INET6_ADDRSTRLEN]; 160 #endif 161 162 ip6 = mtod(m, struct ip6_hdr *); 163 #ifndef PULLDOWN_TEST 164 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 165 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 166 #else 167 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 168 if (ip6f == NULL) 169 return (IPPROTO_DONE); 170 #endif 171 172 dstifp = NULL; 173 #ifdef IN6_IFSTAT_STRICT 174 /* find the destination interface of the packet. */ 175 if ((ia = ip6_getdstifaddr(m)) != NULL) 176 dstifp = ia->ia_ifp; 177 #else 178 /* we are violating the spec, this is not the destination interface */ 179 if ((m->m_flags & M_PKTHDR) != 0) 180 dstifp = m->m_pkthdr.rcvif; 181 #endif 182 183 /* jumbo payload can't contain a fragment header */ 184 if (ip6->ip6_plen == 0) { 185 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 186 in6_ifstat_inc(dstifp, ifs6_reass_fail); 187 return IPPROTO_DONE; 188 } 189 190 /* 191 * check whether fragment packet's fragment length is 192 * multiple of 8 octets. 193 * sizeof(struct ip6_frag) == 8 194 * sizeof(struct ip6_hdr) = 40 195 */ 196 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 197 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 198 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 199 offsetof(struct ip6_hdr, ip6_plen)); 200 in6_ifstat_inc(dstifp, ifs6_reass_fail); 201 return IPPROTO_DONE; 202 } 203 204 ip6stat.ip6s_fragments++; 205 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 206 207 /* offset now points to data portion */ 208 offset += sizeof(struct ip6_frag); 209 210 IP6Q_LOCK(); 211 212 /* 213 * Enforce upper bound on number of fragments. 214 * If maxfrag is 0, never accept fragments. 215 * If maxfrag is -1, accept all fragments without limitation. 216 */ 217 if (ip6_maxfrags < 0) 218 ; 219 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 220 goto dropfrag; 221 222 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 223 if (ip6f->ip6f_ident == q6->ip6q_ident && 224 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 225 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 226 break; 227 228 if (q6 == &ip6q) { 229 /* 230 * the first fragment to arrive, create a reassembly queue. 231 */ 232 first_frag = 1; 233 234 /* 235 * Enforce upper bound on number of fragmented packets 236 * for which we attempt reassembly; 237 * If maxfragpackets is 0, never accept fragments. 238 * If maxfragpackets is -1, accept all fragments without 239 * limitation. 240 */ 241 if (ip6_maxfragpackets < 0) 242 ; 243 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 244 goto dropfrag; 245 frag6_nfragpackets++; 246 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 247 M_NOWAIT); 248 if (q6 == NULL) 249 goto dropfrag; 250 bzero(q6, sizeof(*q6)); 251 252 frag6_insque(q6, &ip6q); 253 254 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 255 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 256 #ifdef notyet 257 q6->ip6q_nxtp = (u_char *)nxtp; 258 #endif 259 q6->ip6q_ident = ip6f->ip6f_ident; 260 q6->ip6q_ttl = IPV6_FRAGTTL; 261 q6->ip6q_src = ip6->ip6_src; 262 q6->ip6q_dst = ip6->ip6_dst; 263 q6->ip6q_ecn = 264 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 265 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 266 267 q6->ip6q_nfrag = 0; 268 } 269 270 /* 271 * If it's the 1st fragment, record the length of the 272 * unfragmentable part and the next header of the fragment header. 273 */ 274 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 275 if (fragoff == 0) { 276 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 277 sizeof(struct ip6_frag); 278 q6->ip6q_nxt = ip6f->ip6f_nxt; 279 } 280 281 /* 282 * Check that the reassembled packet would not exceed 65535 bytes 283 * in size. 284 * If it would exceed, discard the fragment and return an ICMP error. 285 */ 286 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 287 if (q6->ip6q_unfrglen >= 0) { 288 /* The 1st fragment has already arrived. */ 289 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 290 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 291 offset - sizeof(struct ip6_frag) + 292 offsetof(struct ip6_frag, ip6f_offlg)); 293 IP6Q_UNLOCK(); 294 return (IPPROTO_DONE); 295 } 296 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 297 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 298 offset - sizeof(struct ip6_frag) + 299 offsetof(struct ip6_frag, ip6f_offlg)); 300 IP6Q_UNLOCK(); 301 return (IPPROTO_DONE); 302 } 303 /* 304 * If it's the first fragment, do the above check for each 305 * fragment already stored in the reassembly queue. 306 */ 307 if (fragoff == 0) { 308 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 309 af6 = af6dwn) { 310 af6dwn = af6->ip6af_down; 311 312 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 313 IPV6_MAXPACKET) { 314 struct mbuf *merr = IP6_REASS_MBUF(af6); 315 struct ip6_hdr *ip6err; 316 int erroff = af6->ip6af_offset; 317 318 /* dequeue the fragment. */ 319 frag6_deq(af6); 320 free(af6, M_FTABLE); 321 322 /* adjust pointer. */ 323 ip6err = mtod(merr, struct ip6_hdr *); 324 325 /* 326 * Restore source and destination addresses 327 * in the erroneous IPv6 header. 328 */ 329 ip6err->ip6_src = q6->ip6q_src; 330 ip6err->ip6_dst = q6->ip6q_dst; 331 332 icmp6_error(merr, ICMP6_PARAM_PROB, 333 ICMP6_PARAMPROB_HEADER, 334 erroff - sizeof(struct ip6_frag) + 335 offsetof(struct ip6_frag, ip6f_offlg)); 336 } 337 } 338 } 339 340 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 341 M_NOWAIT); 342 if (ip6af == NULL) 343 goto dropfrag; 344 bzero(ip6af, sizeof(*ip6af)); 345 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 346 ip6af->ip6af_off = fragoff; 347 ip6af->ip6af_frglen = frgpartlen; 348 ip6af->ip6af_offset = offset; 349 IP6_REASS_MBUF(ip6af) = m; 350 351 if (first_frag) { 352 af6 = (struct ip6asfrag *)q6; 353 goto insert; 354 } 355 356 /* 357 * Handle ECN by comparing this segment with the first one; 358 * if CE is set, do not lose CE. 359 * drop if CE and not-ECT are mixed for the same packet. 360 */ 361 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 362 ecn0 = q6->ip6q_ecn; 363 if (ecn == IPTOS_ECN_CE) { 364 if (ecn0 == IPTOS_ECN_NOTECT) { 365 free(ip6af, M_FTABLE); 366 goto dropfrag; 367 } 368 if (ecn0 != IPTOS_ECN_CE) 369 q6->ip6q_ecn = IPTOS_ECN_CE; 370 } 371 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 372 free(ip6af, M_FTABLE); 373 goto dropfrag; 374 } 375 376 /* 377 * Find a segment which begins after this one does. 378 */ 379 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 380 af6 = af6->ip6af_down) 381 if (af6->ip6af_off > ip6af->ip6af_off) 382 break; 383 384 #if 0 385 /* 386 * If there is a preceding segment, it may provide some of 387 * our data already. If so, drop the data from the incoming 388 * segment. If it provides all of our data, drop us. 389 */ 390 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 391 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 392 - ip6af->ip6af_off; 393 if (i > 0) { 394 if (i >= ip6af->ip6af_frglen) 395 goto dropfrag; 396 m_adj(IP6_REASS_MBUF(ip6af), i); 397 ip6af->ip6af_off += i; 398 ip6af->ip6af_frglen -= i; 399 } 400 } 401 402 /* 403 * While we overlap succeeding segments trim them or, 404 * if they are completely covered, dequeue them. 405 */ 406 while (af6 != (struct ip6asfrag *)q6 && 407 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 408 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 409 if (i < af6->ip6af_frglen) { 410 af6->ip6af_frglen -= i; 411 af6->ip6af_off += i; 412 m_adj(IP6_REASS_MBUF(af6), i); 413 break; 414 } 415 af6 = af6->ip6af_down; 416 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 417 frag6_deq(af6->ip6af_up); 418 } 419 #else 420 /* 421 * If the incoming framgent overlaps some existing fragments in 422 * the reassembly queue, drop it, since it is dangerous to override 423 * existing fragments from a security point of view. 424 * We don't know which fragment is the bad guy - here we trust 425 * fragment that came in earlier, with no real reason. 426 * 427 * Note: due to changes after disabling this part, mbuf passed to 428 * m_adj() below now does not meet the requirement. 429 */ 430 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 431 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 432 - ip6af->ip6af_off; 433 if (i > 0) { 434 #if 0 /* suppress the noisy log */ 435 log(LOG_ERR, "%d bytes of a fragment from %s " 436 "overlaps the previous fragment\n", 437 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 438 #endif 439 free(ip6af, M_FTABLE); 440 goto dropfrag; 441 } 442 } 443 if (af6 != (struct ip6asfrag *)q6) { 444 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 445 if (i > 0) { 446 #if 0 /* suppress the noisy log */ 447 log(LOG_ERR, "%d bytes of a fragment from %s " 448 "overlaps the succeeding fragment", 449 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 450 #endif 451 free(ip6af, M_FTABLE); 452 goto dropfrag; 453 } 454 } 455 #endif 456 457 insert: 458 459 /* 460 * Stick new segment in its place; 461 * check for complete reassembly. 462 * Move to front of packet queue, as we are 463 * the most recently active fragmented packet. 464 */ 465 frag6_enq(ip6af, af6->ip6af_up); 466 frag6_nfrags++; 467 q6->ip6q_nfrag++; 468 #if 0 /* xxx */ 469 if (q6 != ip6q.ip6q_next) { 470 frag6_remque(q6); 471 frag6_insque(q6, &ip6q); 472 } 473 #endif 474 next = 0; 475 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 476 af6 = af6->ip6af_down) { 477 if (af6->ip6af_off != next) { 478 IP6Q_UNLOCK(); 479 return IPPROTO_DONE; 480 } 481 next += af6->ip6af_frglen; 482 } 483 if (af6->ip6af_up->ip6af_mff) { 484 IP6Q_UNLOCK(); 485 return IPPROTO_DONE; 486 } 487 488 /* 489 * Reassembly is complete; concatenate fragments. 490 */ 491 ip6af = q6->ip6q_down; 492 t = m = IP6_REASS_MBUF(ip6af); 493 af6 = ip6af->ip6af_down; 494 frag6_deq(ip6af); 495 while (af6 != (struct ip6asfrag *)q6) { 496 af6dwn = af6->ip6af_down; 497 frag6_deq(af6); 498 while (t->m_next) 499 t = t->m_next; 500 t->m_next = IP6_REASS_MBUF(af6); 501 m_adj(t->m_next, af6->ip6af_offset); 502 free(af6, M_FTABLE); 503 af6 = af6dwn; 504 } 505 506 /* adjust offset to point where the original next header starts */ 507 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 508 free(ip6af, M_FTABLE); 509 ip6 = mtod(m, struct ip6_hdr *); 510 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 511 if (q6->ip6q_ecn == IPTOS_ECN_CE) 512 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 513 nxt = q6->ip6q_nxt; 514 #ifdef notyet 515 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 516 #endif 517 518 /* Delete frag6 header */ 519 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 520 /* This is the only possible case with !PULLDOWN_TEST */ 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(struct ip6q *q6) 585 { 586 struct ip6asfrag *af6, *down6; 587 588 IP6Q_LOCK_ASSERT(); 589 590 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 591 af6 = down6) { 592 struct mbuf *m = IP6_REASS_MBUF(af6); 593 594 down6 = af6->ip6af_down; 595 frag6_deq(af6); 596 597 /* 598 * Return ICMP time exceeded error for the 1st fragment. 599 * Just free other fragments. 600 */ 601 if (af6->ip6af_off == 0) { 602 struct ip6_hdr *ip6; 603 604 /* adjust pointer */ 605 ip6 = mtod(m, struct ip6_hdr *); 606 607 /* restore source and destination addresses */ 608 ip6->ip6_src = q6->ip6q_src; 609 ip6->ip6_dst = q6->ip6q_dst; 610 611 icmp6_error(m, ICMP6_TIME_EXCEEDED, 612 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 613 } else 614 m_freem(m); 615 free(af6, M_FTABLE); 616 } 617 frag6_remque(q6); 618 frag6_nfrags -= q6->ip6q_nfrag; 619 free(q6, M_FTABLE); 620 frag6_nfragpackets--; 621 } 622 623 /* 624 * Put an ip fragment on a reassembly chain. 625 * Like insque, but pointers in middle of structure. 626 */ 627 void 628 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 629 { 630 631 IP6Q_LOCK_ASSERT(); 632 633 af6->ip6af_up = up6; 634 af6->ip6af_down = up6->ip6af_down; 635 up6->ip6af_down->ip6af_up = af6; 636 up6->ip6af_down = af6; 637 } 638 639 /* 640 * To frag6_enq as remque is to insque. 641 */ 642 void 643 frag6_deq(struct ip6asfrag *af6) 644 { 645 646 IP6Q_LOCK_ASSERT(); 647 648 af6->ip6af_up->ip6af_down = af6->ip6af_down; 649 af6->ip6af_down->ip6af_up = af6->ip6af_up; 650 } 651 652 void 653 frag6_insque(struct ip6q *new, struct ip6q *old) 654 { 655 656 IP6Q_LOCK_ASSERT(); 657 658 new->ip6q_prev = old; 659 new->ip6q_next = old->ip6q_next; 660 old->ip6q_next->ip6q_prev= new; 661 old->ip6q_next = new; 662 } 663 664 void 665 frag6_remque(struct ip6q *p6) 666 { 667 668 IP6Q_LOCK_ASSERT(); 669 670 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 671 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 672 } 673 674 /* 675 * IPv6 reassembling timer processing; 676 * if a timer expires on a reassembly 677 * queue, discard it. 678 */ 679 void 680 frag6_slowtimo(void) 681 { 682 struct ip6q *q6; 683 684 #if 0 685 GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */ 686 #endif 687 688 IP6Q_LOCK(); 689 q6 = ip6q.ip6q_next; 690 if (q6) 691 while (q6 != &ip6q) { 692 --q6->ip6q_ttl; 693 q6 = q6->ip6q_next; 694 if (q6->ip6q_prev->ip6q_ttl == 0) { 695 ip6stat.ip6s_fragtimeout++; 696 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 697 frag6_freef(q6->ip6q_prev); 698 } 699 } 700 /* 701 * If we are over the maximum number of fragments 702 * (due to the limit being lowered), drain off 703 * enough to get down to the new limit. 704 */ 705 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 706 ip6q.ip6q_prev) { 707 ip6stat.ip6s_fragoverflow++; 708 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 709 frag6_freef(ip6q.ip6q_prev); 710 } 711 IP6Q_UNLOCK(); 712 713 #if 0 714 /* 715 * Routing changes might produce a better route than we last used; 716 * make sure we notice eventually, even if forwarding only for one 717 * destination and the cache is never replaced. 718 */ 719 if (ip6_forward_rt.ro_rt) { 720 RTFREE(ip6_forward_rt.ro_rt); 721 ip6_forward_rt.ro_rt = 0; 722 } 723 if (ipsrcchk_rt.ro_rt) { 724 RTFREE(ipsrcchk_rt.ro_rt); 725 ipsrcchk_rt.ro_rt = 0; 726 } 727 #endif 728 } 729 730 /* 731 * Drain off all datagram fragments. 732 */ 733 void 734 frag6_drain(void) 735 { 736 737 if (IP6Q_TRYLOCK() == 0) 738 return; 739 while (ip6q.ip6q_next != &ip6q) { 740 ip6stat.ip6s_fragdropped++; 741 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 742 frag6_freef(ip6q.ip6q_next); 743 } 744 IP6Q_UNLOCK(); 745 }
Cache object: 63a4250fb3d957a29cdc20b16fb8638e
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]