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: releng/5.2/sys/netinet6/frag6.c 121684 2003-10-29 15:07:04Z ume $ */ 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 "opt_random_ip_id.h" 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 #include <net/net_osdep.h> 59 60 /* 61 * Define it to get a correct behavior on per-interface statistics. 62 * You will need to perform an extra routing table lookup, per fragment, 63 * to do it. This may, or may not be, a performance hit. 64 */ 65 #define IN6_IFSTAT_STRICT 66 67 static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 68 static void frag6_deq __P((struct ip6asfrag *)); 69 static void frag6_insque __P((struct ip6q *, struct ip6q *)); 70 static void frag6_remque __P((struct ip6q *)); 71 static void frag6_freef __P((struct ip6q *)); 72 73 static struct mtx ip6qlock; 74 /* 75 * These fields all protected by ip6qlock. 76 */ 77 static u_int frag6_nfragpackets; 78 static u_int frag6_nfrags; 79 static struct ip6q ip6q; /* ip6 reassemble queue */ 80 81 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 82 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 83 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 84 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 85 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 86 87 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 88 89 /* 90 * Initialise reassembly queue and fragment identifier. 91 */ 92 void 93 frag6_init() 94 { 95 96 ip6_maxfragpackets = nmbclusters / 4; 97 ip6_maxfrags = nmbclusters / 4; 98 99 IP6Q_LOCK_INIT(); 100 101 #ifndef RANDOM_IP_ID 102 ip6_id = arc4random(); 103 #endif 104 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 105 } 106 107 /* 108 * In RFC2460, fragment and reassembly rule do not agree with each other, 109 * in terms of next header field handling in fragment header. 110 * While the sender will use the same value for all of the fragmented packets, 111 * receiver is suggested not to check the consistency. 112 * 113 * fragment rule (p20): 114 * (2) A Fragment header containing: 115 * The Next Header value that identifies the first header of 116 * the Fragmentable Part of the original packet. 117 * -> next header field is same for all fragments 118 * 119 * reassembly rule (p21): 120 * The Next Header field of the last header of the Unfragmentable 121 * Part is obtained from the Next Header field of the first 122 * fragment's Fragment header. 123 * -> should grab it from the first fragment only 124 * 125 * The following note also contradicts with fragment rule - noone is going to 126 * send different fragment with different next header field. 127 * 128 * additional note (p22): 129 * The Next Header values in the Fragment headers of different 130 * fragments of the same original packet may differ. Only the value 131 * from the Offset zero fragment packet is used for reassembly. 132 * -> should grab it from the first fragment only 133 * 134 * There is no explicit reason given in the RFC. Historical reason maybe? 135 */ 136 /* 137 * Fragment input 138 */ 139 int 140 frag6_input(mp, offp, proto) 141 struct mbuf **mp; 142 int *offp, proto; 143 { 144 struct mbuf *m = *mp, *t; 145 struct ip6_hdr *ip6; 146 struct ip6_frag *ip6f; 147 struct ip6q *q6; 148 struct ip6asfrag *af6, *ip6af, *af6dwn; 149 #ifdef IN6_IFSTAT_STRICT 150 struct in6_ifaddr *ia; 151 #endif 152 int offset = *offp, nxt, i, next; 153 int first_frag = 0; 154 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 155 struct ifnet *dstifp; 156 u_int8_t ecn, ecn0; 157 158 ip6 = mtod(m, struct ip6_hdr *); 159 #ifndef PULLDOWN_TEST 160 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 161 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 162 #else 163 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 164 if (ip6f == NULL) 165 return (IPPROTO_DONE); 166 #endif 167 168 dstifp = NULL; 169 #ifdef IN6_IFSTAT_STRICT 170 /* find the destination interface of the packet. */ 171 if ((ia = ip6_getdstifaddr(m)) != NULL) 172 dstifp = ia->ia_ifp; 173 #else 174 /* we are violating the spec, this is not the destination interface */ 175 if ((m->m_flags & M_PKTHDR) != 0) 176 dstifp = m->m_pkthdr.rcvif; 177 #endif 178 179 /* jumbo payload can't contain a fragment header */ 180 if (ip6->ip6_plen == 0) { 181 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 182 in6_ifstat_inc(dstifp, ifs6_reass_fail); 183 return IPPROTO_DONE; 184 } 185 186 /* 187 * check whether fragment packet's fragment length is 188 * multiple of 8 octets. 189 * sizeof(struct ip6_frag) == 8 190 * sizeof(struct ip6_hdr) = 40 191 */ 192 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 193 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 194 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 195 offsetof(struct ip6_hdr, ip6_plen)); 196 in6_ifstat_inc(dstifp, ifs6_reass_fail); 197 return IPPROTO_DONE; 198 } 199 200 ip6stat.ip6s_fragments++; 201 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 202 203 /* offset now points to data portion */ 204 offset += sizeof(struct ip6_frag); 205 206 IP6Q_LOCK(); 207 208 /* 209 * Enforce upper bound on number of fragments. 210 * If maxfrag is 0, never accept fragments. 211 * If maxfrag is -1, accept all fragments without limitation. 212 */ 213 if (ip6_maxfrags < 0) 214 ; 215 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 216 goto dropfrag; 217 218 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 219 if (ip6f->ip6f_ident == q6->ip6q_ident && 220 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 221 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 222 break; 223 224 if (q6 == &ip6q) { 225 /* 226 * the first fragment to arrive, create a reassembly queue. 227 */ 228 first_frag = 1; 229 230 /* 231 * Enforce upper bound on number of fragmented packets 232 * for which we attempt reassembly; 233 * If maxfragpackets is 0, never accept fragments. 234 * If maxfragpackets is -1, accept all fragments without 235 * limitation. 236 */ 237 if (ip6_maxfragpackets < 0) 238 ; 239 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 240 goto dropfrag; 241 frag6_nfragpackets++; 242 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 243 M_NOWAIT); 244 if (q6 == NULL) 245 goto dropfrag; 246 bzero(q6, sizeof(*q6)); 247 248 frag6_insque(q6, &ip6q); 249 250 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 251 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 252 #ifdef notyet 253 q6->ip6q_nxtp = (u_char *)nxtp; 254 #endif 255 q6->ip6q_ident = ip6f->ip6f_ident; 256 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 257 q6->ip6q_ttl = IPV6_FRAGTTL; 258 q6->ip6q_src = ip6->ip6_src; 259 q6->ip6q_dst = ip6->ip6_dst; 260 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 261 262 q6->ip6q_nfrag = 0; 263 } 264 265 /* 266 * If it's the 1st fragment, record the length of the 267 * unfragmentable part and the next header of the fragment header. 268 */ 269 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 270 if (fragoff == 0) { 271 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 272 sizeof(struct ip6_frag); 273 q6->ip6q_nxt = ip6f->ip6f_nxt; 274 } 275 276 /* 277 * Check that the reassembled packet would not exceed 65535 bytes 278 * in size. 279 * If it would exceed, discard the fragment and return an ICMP error. 280 */ 281 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 282 if (q6->ip6q_unfrglen >= 0) { 283 /* The 1st fragment has already arrived. */ 284 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 285 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 286 offset - sizeof(struct ip6_frag) + 287 offsetof(struct ip6_frag, ip6f_offlg)); 288 IP6Q_UNLOCK(); 289 return (IPPROTO_DONE); 290 } 291 } else if (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 /* 299 * If it's the first fragment, do the above check for each 300 * fragment already stored in the reassembly queue. 301 */ 302 if (fragoff == 0) { 303 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 304 af6 = af6dwn) { 305 af6dwn = af6->ip6af_down; 306 307 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 308 IPV6_MAXPACKET) { 309 struct mbuf *merr = IP6_REASS_MBUF(af6); 310 struct ip6_hdr *ip6err; 311 int erroff = af6->ip6af_offset; 312 313 /* dequeue the fragment. */ 314 frag6_deq(af6); 315 free(af6, M_FTABLE); 316 317 /* adjust pointer. */ 318 ip6err = mtod(merr, struct ip6_hdr *); 319 320 /* 321 * Restore source and destination addresses 322 * in the erroneous IPv6 header. 323 */ 324 ip6err->ip6_src = q6->ip6q_src; 325 ip6err->ip6_dst = q6->ip6q_dst; 326 327 icmp6_error(merr, ICMP6_PARAM_PROB, 328 ICMP6_PARAMPROB_HEADER, 329 erroff - sizeof(struct ip6_frag) + 330 offsetof(struct ip6_frag, ip6f_offlg)); 331 } 332 } 333 } 334 335 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 336 M_NOWAIT); 337 if (ip6af == NULL) 338 goto dropfrag; 339 bzero(ip6af, sizeof(*ip6af)); 340 ip6af->ip6af_head = ip6->ip6_flow; 341 ip6af->ip6af_len = ip6->ip6_plen; 342 ip6af->ip6af_nxt = ip6->ip6_nxt; 343 ip6af->ip6af_hlim = ip6->ip6_hlim; 344 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 345 ip6af->ip6af_off = fragoff; 346 ip6af->ip6af_frglen = frgpartlen; 347 ip6af->ip6af_offset = offset; 348 IP6_REASS_MBUF(ip6af) = m; 349 350 if (first_frag) { 351 af6 = (struct ip6asfrag *)q6; 352 goto insert; 353 } 354 355 /* 356 * Handle ECN by comparing this segment with the first one; 357 * if CE is set, do not lose CE. 358 * drop if CE and not-ECT are mixed for the same packet. 359 */ 360 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 361 ecn0 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK; 362 if (ecn == IPTOS_ECN_CE) { 363 if (ecn0 == IPTOS_ECN_NOTECT) { 364 free(ip6af, M_FTABLE); 365 goto dropfrag; 366 } 367 if (ecn0 != IPTOS_ECN_CE) 368 q6->ip6q_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20); 369 } 370 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 371 free(ip6af, M_FTABLE); 372 goto dropfrag; 373 } 374 375 /* 376 * Find a segment which begins after this one does. 377 */ 378 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 379 af6 = af6->ip6af_down) 380 if (af6->ip6af_off > ip6af->ip6af_off) 381 break; 382 383 #if 0 384 /* 385 * If there is a preceding segment, it may provide some of 386 * our data already. If so, drop the data from the incoming 387 * segment. If it provides all of our data, drop us. 388 */ 389 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 390 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 391 - ip6af->ip6af_off; 392 if (i > 0) { 393 if (i >= ip6af->ip6af_frglen) 394 goto dropfrag; 395 m_adj(IP6_REASS_MBUF(ip6af), i); 396 ip6af->ip6af_off += i; 397 ip6af->ip6af_frglen -= i; 398 } 399 } 400 401 /* 402 * While we overlap succeeding segments trim them or, 403 * if they are completely covered, dequeue them. 404 */ 405 while (af6 != (struct ip6asfrag *)q6 && 406 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 407 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 408 if (i < af6->ip6af_frglen) { 409 af6->ip6af_frglen -= i; 410 af6->ip6af_off += i; 411 m_adj(IP6_REASS_MBUF(af6), i); 412 break; 413 } 414 af6 = af6->ip6af_down; 415 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 416 frag6_deq(af6->ip6af_up); 417 } 418 #else 419 /* 420 * If the incoming framgent overlaps some existing fragments in 421 * the reassembly queue, drop it, since it is dangerous to override 422 * existing fragments from a security point of view. 423 * We don't know which fragment is the bad guy - here we trust 424 * fragment that came in earlier, with no real reason. 425 */ 426 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 427 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 428 - ip6af->ip6af_off; 429 if (i > 0) { 430 #if 0 /* suppress the noisy log */ 431 log(LOG_ERR, "%d bytes of a fragment from %s " 432 "overlaps the previous fragment\n", 433 i, ip6_sprintf(&q6->ip6q_src)); 434 #endif 435 free(ip6af, M_FTABLE); 436 goto dropfrag; 437 } 438 } 439 if (af6 != (struct ip6asfrag *)q6) { 440 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 441 if (i > 0) { 442 #if 0 /* suppress the noisy log */ 443 log(LOG_ERR, "%d bytes of a fragment from %s " 444 "overlaps the succeeding fragment", 445 i, ip6_sprintf(&q6->ip6q_src)); 446 #endif 447 free(ip6af, M_FTABLE); 448 goto dropfrag; 449 } 450 } 451 #endif 452 453 insert: 454 455 /* 456 * Stick new segment in its place; 457 * check for complete reassembly. 458 * Move to front of packet queue, as we are 459 * the most recently active fragmented packet. 460 */ 461 frag6_enq(ip6af, af6->ip6af_up); 462 frag6_nfrags++; 463 q6->ip6q_nfrag++; 464 #if 0 /* xxx */ 465 if (q6 != ip6q.ip6q_next) { 466 frag6_remque(q6); 467 frag6_insque(q6, &ip6q); 468 } 469 #endif 470 next = 0; 471 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 472 af6 = af6->ip6af_down) { 473 if (af6->ip6af_off != next) { 474 IP6Q_UNLOCK(); 475 return IPPROTO_DONE; 476 } 477 next += af6->ip6af_frglen; 478 } 479 if (af6->ip6af_up->ip6af_mff) { 480 IP6Q_UNLOCK(); 481 return IPPROTO_DONE; 482 } 483 484 /* 485 * Reassembly is complete; concatenate fragments. 486 */ 487 ip6af = q6->ip6q_down; 488 t = m = IP6_REASS_MBUF(ip6af); 489 af6 = ip6af->ip6af_down; 490 frag6_deq(ip6af); 491 while (af6 != (struct ip6asfrag *)q6) { 492 af6dwn = af6->ip6af_down; 493 frag6_deq(af6); 494 while (t->m_next) 495 t = t->m_next; 496 t->m_next = IP6_REASS_MBUF(af6); 497 m_adj(t->m_next, af6->ip6af_offset); 498 free(af6, M_FTABLE); 499 af6 = af6dwn; 500 } 501 502 /* adjust offset to point where the original next header starts */ 503 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 504 free(ip6af, M_FTABLE); 505 ip6 = mtod(m, struct ip6_hdr *); 506 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 507 ip6->ip6_src = q6->ip6q_src; 508 ip6->ip6_dst = q6->ip6q_dst; 509 nxt = q6->ip6q_nxt; 510 #ifdef notyet 511 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 512 #endif 513 514 /* 515 * Delete frag6 header with as a few cost as possible. 516 */ 517 if (offset < m->m_len) { 518 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 519 offset); 520 m->m_data += sizeof(struct ip6_frag); 521 m->m_len -= sizeof(struct ip6_frag); 522 } else { 523 /* this comes with no copy if the boundary is on cluster */ 524 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 525 frag6_remque(q6); 526 frag6_nfrags -= q6->ip6q_nfrag; 527 free(q6, M_FTABLE); 528 frag6_nfragpackets--; 529 goto dropfrag; 530 } 531 m_adj(t, sizeof(struct ip6_frag)); 532 m_cat(m, t); 533 } 534 535 /* 536 * Store NXT to the original. 537 */ 538 { 539 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 540 *prvnxtp = nxt; 541 } 542 543 frag6_remque(q6); 544 frag6_nfrags -= q6->ip6q_nfrag; 545 free(q6, M_FTABLE); 546 frag6_nfragpackets--; 547 548 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 549 int plen = 0; 550 for (t = m; t; t = t->m_next) 551 plen += t->m_len; 552 m->m_pkthdr.len = plen; 553 } 554 555 ip6stat.ip6s_reassembled++; 556 in6_ifstat_inc(dstifp, ifs6_reass_ok); 557 558 /* 559 * Tell launch routine the next header 560 */ 561 562 *mp = m; 563 *offp = offset; 564 565 IP6Q_UNLOCK(); 566 return nxt; 567 568 dropfrag: 569 IP6Q_UNLOCK(); 570 in6_ifstat_inc(dstifp, ifs6_reass_fail); 571 ip6stat.ip6s_fragdropped++; 572 m_freem(m); 573 return IPPROTO_DONE; 574 } 575 576 /* 577 * Free a fragment reassembly header and all 578 * associated datagrams. 579 */ 580 void 581 frag6_freef(q6) 582 struct ip6q *q6; 583 { 584 struct ip6asfrag *af6, *down6; 585 586 IP6Q_LOCK_ASSERT(); 587 588 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 589 af6 = down6) { 590 struct mbuf *m = IP6_REASS_MBUF(af6); 591 592 down6 = af6->ip6af_down; 593 frag6_deq(af6); 594 595 /* 596 * Return ICMP time exceeded error for the 1st fragment. 597 * Just free other fragments. 598 */ 599 if (af6->ip6af_off == 0) { 600 struct ip6_hdr *ip6; 601 602 /* adjust pointer */ 603 ip6 = mtod(m, struct ip6_hdr *); 604 605 /* restore source and destination addresses */ 606 ip6->ip6_src = q6->ip6q_src; 607 ip6->ip6_dst = q6->ip6q_dst; 608 609 icmp6_error(m, ICMP6_TIME_EXCEEDED, 610 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 611 } else 612 m_freem(m); 613 free(af6, M_FTABLE); 614 } 615 frag6_remque(q6); 616 frag6_nfrags -= q6->ip6q_nfrag; 617 free(q6, M_FTABLE); 618 frag6_nfragpackets--; 619 } 620 621 /* 622 * Put an ip fragment on a reassembly chain. 623 * Like insque, but pointers in middle of structure. 624 */ 625 void 626 frag6_enq(af6, up6) 627 struct ip6asfrag *af6, *up6; 628 { 629 630 IP6Q_LOCK_ASSERT(); 631 632 af6->ip6af_up = up6; 633 af6->ip6af_down = up6->ip6af_down; 634 up6->ip6af_down->ip6af_up = af6; 635 up6->ip6af_down = af6; 636 } 637 638 /* 639 * To frag6_enq as remque is to insque. 640 */ 641 void 642 frag6_deq(af6) 643 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(new, old) 654 struct ip6q *new, *old; 655 { 656 657 IP6Q_LOCK_ASSERT(); 658 659 new->ip6q_prev = old; 660 new->ip6q_next = old->ip6q_next; 661 old->ip6q_next->ip6q_prev= new; 662 old->ip6q_next = new; 663 } 664 665 void 666 frag6_remque(p6) 667 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() 683 { 684 struct ip6q *q6; 685 int s = splnet(); 686 687 IP6Q_LOCK(); 688 q6 = ip6q.ip6q_next; 689 if (q6) 690 while (q6 != &ip6q) { 691 --q6->ip6q_ttl; 692 q6 = q6->ip6q_next; 693 if (q6->ip6q_prev->ip6q_ttl == 0) { 694 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 (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 705 ip6q.ip6q_prev) { 706 ip6stat.ip6s_fragoverflow++; 707 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 708 frag6_freef(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 (ip6_forward_rt.ro_rt) { 719 RTFREE(ip6_forward_rt.ro_rt); 720 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 splx(s); 729 } 730 731 /* 732 * Drain off all datagram fragments. 733 */ 734 void 735 frag6_drain() 736 { 737 738 if (IP6Q_TRYLOCK() == 0) 739 return; 740 while (ip6q.ip6q_next != &ip6q) { 741 ip6stat.ip6s_fragdropped++; 742 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 743 frag6_freef(ip6q.ip6q_next); 744 } 745 IP6Q_UNLOCK(); 746 }
Cache object: 17b3b039de407085acb70ce08004a339
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]