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sys/netinet6/frag6.c
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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: releng/8.0/sys/netinet6/frag6.c 196019 2009-08-01 19:26:27Z rwatson $"); 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 #include <net/vnet.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 #include <security/mac/mac_framework.h> 60 61 /* 62 * Define it to get a correct behavior on per-interface statistics. 63 * You will need to perform an extra routing table lookup, per fragment, 64 * to do it. This may, or may not be, a performance hit. 65 */ 66 #define IN6_IFSTAT_STRICT 67 68 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 69 static void frag6_deq(struct ip6asfrag *); 70 static void frag6_insque(struct ip6q *, struct ip6q *); 71 static void frag6_remque(struct ip6q *); 72 static void frag6_freef(struct ip6q *); 73 74 static struct mtx ip6qlock; 75 /* 76 * These fields all protected by ip6qlock. 77 */ 78 static VNET_DEFINE(u_int, frag6_nfragpackets); 79 static VNET_DEFINE(u_int, frag6_nfrags); 80 static VNET_DEFINE(struct ip6q, ip6q); /* ip6 reassemble queue */ 81 82 #define V_frag6_nfragpackets VNET(frag6_nfragpackets) 83 #define V_frag6_nfrags VNET(frag6_nfrags) 84 #define V_ip6q VNET(ip6q) 85 86 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 87 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 88 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 89 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 90 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 91 92 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 93 94 /* 95 * Initialise reassembly queue and fragment identifier. 96 */ 97 static void 98 frag6_change(void *tag) 99 { 100 101 V_ip6_maxfragpackets = nmbclusters / 4; 102 V_ip6_maxfrags = nmbclusters / 4; 103 } 104 105 void 106 frag6_init(void) 107 { 108 109 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 110 V_ip6_maxfragpackets = nmbclusters / 4; 111 V_ip6_maxfrags = nmbclusters / 4; 112 113 if (!IS_DEFAULT_VNET(curvnet)) 114 return; 115 116 IP6Q_LOCK_INIT(); 117 EVENTHANDLER_REGISTER(nmbclusters_change, 118 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 119 } 120 121 /* 122 * In RFC2460, fragment and reassembly rule do not agree with each other, 123 * in terms of next header field handling in fragment header. 124 * While the sender will use the same value for all of the fragmented packets, 125 * receiver is suggested not to check the consistency. 126 * 127 * fragment rule (p20): 128 * (2) A Fragment header containing: 129 * The Next Header value that identifies the first header of 130 * the Fragmentable Part of the original packet. 131 * -> next header field is same for all fragments 132 * 133 * reassembly rule (p21): 134 * The Next Header field of the last header of the Unfragmentable 135 * Part is obtained from the Next Header field of the first 136 * fragment's Fragment header. 137 * -> should grab it from the first fragment only 138 * 139 * The following note also contradicts with fragment rule - noone is going to 140 * send different fragment with different next header field. 141 * 142 * additional note (p22): 143 * The Next Header values in the Fragment headers of different 144 * fragments of the same original packet may differ. Only the value 145 * from the Offset zero fragment packet is used for reassembly. 146 * -> should grab it from the first fragment only 147 * 148 * There is no explicit reason given in the RFC. Historical reason maybe? 149 */ 150 /* 151 * Fragment input 152 */ 153 int 154 frag6_input(struct mbuf **mp, int *offp, int proto) 155 { 156 struct mbuf *m = *mp, *t; 157 struct ip6_hdr *ip6; 158 struct ip6_frag *ip6f; 159 struct ip6q *q6; 160 struct ip6asfrag *af6, *ip6af, *af6dwn; 161 #ifdef IN6_IFSTAT_STRICT 162 struct in6_ifaddr *ia; 163 #endif 164 int offset = *offp, nxt, i, next; 165 int first_frag = 0; 166 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 167 struct ifnet *dstifp; 168 u_int8_t ecn, ecn0; 169 #if 0 170 char ip6buf[INET6_ADDRSTRLEN]; 171 #endif 172 173 ip6 = mtod(m, struct ip6_hdr *); 174 #ifndef PULLDOWN_TEST 175 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 176 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 177 #else 178 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 179 if (ip6f == NULL) 180 return (IPPROTO_DONE); 181 #endif 182 183 dstifp = NULL; 184 #ifdef IN6_IFSTAT_STRICT 185 /* find the destination interface of the packet. */ 186 if ((ia = ip6_getdstifaddr(m)) != NULL) { 187 dstifp = ia->ia_ifp; 188 ifa_free(&ia->ia_ifa); 189 } 190 #else 191 /* we are violating the spec, this is not the destination interface */ 192 if ((m->m_flags & M_PKTHDR) != 0) 193 dstifp = m->m_pkthdr.rcvif; 194 #endif 195 196 /* jumbo payload can't contain a fragment header */ 197 if (ip6->ip6_plen == 0) { 198 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 199 in6_ifstat_inc(dstifp, ifs6_reass_fail); 200 return IPPROTO_DONE; 201 } 202 203 /* 204 * check whether fragment packet's fragment length is 205 * multiple of 8 octets. 206 * sizeof(struct ip6_frag) == 8 207 * sizeof(struct ip6_hdr) = 40 208 */ 209 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 210 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 211 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 212 offsetof(struct ip6_hdr, ip6_plen)); 213 in6_ifstat_inc(dstifp, ifs6_reass_fail); 214 return IPPROTO_DONE; 215 } 216 217 V_ip6stat.ip6s_fragments++; 218 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 219 220 /* offset now points to data portion */ 221 offset += sizeof(struct ip6_frag); 222 223 IP6Q_LOCK(); 224 225 /* 226 * Enforce upper bound on number of fragments. 227 * If maxfrag is 0, never accept fragments. 228 * If maxfrag is -1, accept all fragments without limitation. 229 */ 230 if (V_ip6_maxfrags < 0) 231 ; 232 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 233 goto dropfrag; 234 235 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 236 if (ip6f->ip6f_ident == q6->ip6q_ident && 237 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 238 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 239 #ifdef MAC 240 && mac_ip6q_match(m, q6) 241 #endif 242 ) 243 break; 244 245 if (q6 == &V_ip6q) { 246 /* 247 * the first fragment to arrive, create a reassembly queue. 248 */ 249 first_frag = 1; 250 251 /* 252 * Enforce upper bound on number of fragmented packets 253 * for which we attempt reassembly; 254 * If maxfragpackets is 0, never accept fragments. 255 * If maxfragpackets is -1, accept all fragments without 256 * limitation. 257 */ 258 if (V_ip6_maxfragpackets < 0) 259 ; 260 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 261 goto dropfrag; 262 V_frag6_nfragpackets++; 263 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 264 M_NOWAIT); 265 if (q6 == NULL) 266 goto dropfrag; 267 bzero(q6, sizeof(*q6)); 268 #ifdef MAC 269 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 270 free(q6, M_FTABLE); 271 goto dropfrag; 272 } 273 mac_ip6q_create(m, q6); 274 #endif 275 frag6_insque(q6, &V_ip6q); 276 277 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 278 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 279 #ifdef notyet 280 q6->ip6q_nxtp = (u_char *)nxtp; 281 #endif 282 q6->ip6q_ident = ip6f->ip6f_ident; 283 q6->ip6q_ttl = IPV6_FRAGTTL; 284 q6->ip6q_src = ip6->ip6_src; 285 q6->ip6q_dst = ip6->ip6_dst; 286 q6->ip6q_ecn = 287 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 288 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 289 290 q6->ip6q_nfrag = 0; 291 } 292 293 /* 294 * If it's the 1st fragment, record the length of the 295 * unfragmentable part and the next header of the fragment header. 296 */ 297 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 298 if (fragoff == 0) { 299 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 300 sizeof(struct ip6_frag); 301 q6->ip6q_nxt = ip6f->ip6f_nxt; 302 } 303 304 /* 305 * Check that the reassembled packet would not exceed 65535 bytes 306 * in size. 307 * If it would exceed, discard the fragment and return an ICMP error. 308 */ 309 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 310 if (q6->ip6q_unfrglen >= 0) { 311 /* The 1st fragment has already arrived. */ 312 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 313 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 314 offset - sizeof(struct ip6_frag) + 315 offsetof(struct ip6_frag, ip6f_offlg)); 316 IP6Q_UNLOCK(); 317 return (IPPROTO_DONE); 318 } 319 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 320 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 321 offset - sizeof(struct ip6_frag) + 322 offsetof(struct ip6_frag, ip6f_offlg)); 323 IP6Q_UNLOCK(); 324 return (IPPROTO_DONE); 325 } 326 /* 327 * If it's the first fragment, do the above check for each 328 * fragment already stored in the reassembly queue. 329 */ 330 if (fragoff == 0) { 331 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 332 af6 = af6dwn) { 333 af6dwn = af6->ip6af_down; 334 335 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 336 IPV6_MAXPACKET) { 337 struct mbuf *merr = IP6_REASS_MBUF(af6); 338 struct ip6_hdr *ip6err; 339 int erroff = af6->ip6af_offset; 340 341 /* dequeue the fragment. */ 342 frag6_deq(af6); 343 free(af6, M_FTABLE); 344 345 /* adjust pointer. */ 346 ip6err = mtod(merr, struct ip6_hdr *); 347 348 /* 349 * Restore source and destination addresses 350 * in the erroneous IPv6 header. 351 */ 352 ip6err->ip6_src = q6->ip6q_src; 353 ip6err->ip6_dst = q6->ip6q_dst; 354 355 icmp6_error(merr, ICMP6_PARAM_PROB, 356 ICMP6_PARAMPROB_HEADER, 357 erroff - sizeof(struct ip6_frag) + 358 offsetof(struct ip6_frag, ip6f_offlg)); 359 } 360 } 361 } 362 363 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 364 M_NOWAIT); 365 if (ip6af == NULL) 366 goto dropfrag; 367 bzero(ip6af, sizeof(*ip6af)); 368 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 369 ip6af->ip6af_off = fragoff; 370 ip6af->ip6af_frglen = frgpartlen; 371 ip6af->ip6af_offset = offset; 372 IP6_REASS_MBUF(ip6af) = m; 373 374 if (first_frag) { 375 af6 = (struct ip6asfrag *)q6; 376 goto insert; 377 } 378 379 /* 380 * Handle ECN by comparing this segment with the first one; 381 * if CE is set, do not lose CE. 382 * drop if CE and not-ECT are mixed for the same packet. 383 */ 384 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 385 ecn0 = q6->ip6q_ecn; 386 if (ecn == IPTOS_ECN_CE) { 387 if (ecn0 == IPTOS_ECN_NOTECT) { 388 free(ip6af, M_FTABLE); 389 goto dropfrag; 390 } 391 if (ecn0 != IPTOS_ECN_CE) 392 q6->ip6q_ecn = IPTOS_ECN_CE; 393 } 394 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 395 free(ip6af, M_FTABLE); 396 goto dropfrag; 397 } 398 399 /* 400 * Find a segment which begins after this one does. 401 */ 402 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 403 af6 = af6->ip6af_down) 404 if (af6->ip6af_off > ip6af->ip6af_off) 405 break; 406 407 #if 0 408 /* 409 * If there is a preceding segment, it may provide some of 410 * our data already. If so, drop the data from the incoming 411 * segment. If it provides all of our data, drop us. 412 */ 413 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 414 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 415 - ip6af->ip6af_off; 416 if (i > 0) { 417 if (i >= ip6af->ip6af_frglen) 418 goto dropfrag; 419 m_adj(IP6_REASS_MBUF(ip6af), i); 420 ip6af->ip6af_off += i; 421 ip6af->ip6af_frglen -= i; 422 } 423 } 424 425 /* 426 * While we overlap succeeding segments trim them or, 427 * if they are completely covered, dequeue them. 428 */ 429 while (af6 != (struct ip6asfrag *)q6 && 430 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 431 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 432 if (i < af6->ip6af_frglen) { 433 af6->ip6af_frglen -= i; 434 af6->ip6af_off += i; 435 m_adj(IP6_REASS_MBUF(af6), i); 436 break; 437 } 438 af6 = af6->ip6af_down; 439 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 440 frag6_deq(af6->ip6af_up); 441 } 442 #else 443 /* 444 * If the incoming framgent overlaps some existing fragments in 445 * the reassembly queue, drop it, since it is dangerous to override 446 * existing fragments from a security point of view. 447 * We don't know which fragment is the bad guy - here we trust 448 * fragment that came in earlier, with no real reason. 449 * 450 * Note: due to changes after disabling this part, mbuf passed to 451 * m_adj() below now does not meet the requirement. 452 */ 453 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 454 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 455 - ip6af->ip6af_off; 456 if (i > 0) { 457 #if 0 /* suppress the noisy log */ 458 log(LOG_ERR, "%d bytes of a fragment from %s " 459 "overlaps the previous fragment\n", 460 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 461 #endif 462 free(ip6af, M_FTABLE); 463 goto dropfrag; 464 } 465 } 466 if (af6 != (struct ip6asfrag *)q6) { 467 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 468 if (i > 0) { 469 #if 0 /* suppress the noisy log */ 470 log(LOG_ERR, "%d bytes of a fragment from %s " 471 "overlaps the succeeding fragment", 472 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 473 #endif 474 free(ip6af, M_FTABLE); 475 goto dropfrag; 476 } 477 } 478 #endif 479 480 insert: 481 #ifdef MAC 482 if (!first_frag) 483 mac_ip6q_update(m, q6); 484 #endif 485 486 /* 487 * Stick new segment in its place; 488 * check for complete reassembly. 489 * Move to front of packet queue, as we are 490 * the most recently active fragmented packet. 491 */ 492 frag6_enq(ip6af, af6->ip6af_up); 493 V_frag6_nfrags++; 494 q6->ip6q_nfrag++; 495 #if 0 /* xxx */ 496 if (q6 != V_ip6q.ip6q_next) { 497 frag6_remque(q6); 498 frag6_insque(q6, &V_ip6q); 499 } 500 #endif 501 next = 0; 502 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 503 af6 = af6->ip6af_down) { 504 if (af6->ip6af_off != next) { 505 IP6Q_UNLOCK(); 506 return IPPROTO_DONE; 507 } 508 next += af6->ip6af_frglen; 509 } 510 if (af6->ip6af_up->ip6af_mff) { 511 IP6Q_UNLOCK(); 512 return IPPROTO_DONE; 513 } 514 515 /* 516 * Reassembly is complete; concatenate fragments. 517 */ 518 ip6af = q6->ip6q_down; 519 t = m = IP6_REASS_MBUF(ip6af); 520 af6 = ip6af->ip6af_down; 521 frag6_deq(ip6af); 522 while (af6 != (struct ip6asfrag *)q6) { 523 af6dwn = af6->ip6af_down; 524 frag6_deq(af6); 525 while (t->m_next) 526 t = t->m_next; 527 t->m_next = IP6_REASS_MBUF(af6); 528 m_adj(t->m_next, af6->ip6af_offset); 529 free(af6, M_FTABLE); 530 af6 = af6dwn; 531 } 532 533 /* adjust offset to point where the original next header starts */ 534 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 535 free(ip6af, M_FTABLE); 536 ip6 = mtod(m, struct ip6_hdr *); 537 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 538 if (q6->ip6q_ecn == IPTOS_ECN_CE) 539 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 540 nxt = q6->ip6q_nxt; 541 #ifdef notyet 542 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 543 #endif 544 545 /* Delete frag6 header */ 546 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 547 /* This is the only possible case with !PULLDOWN_TEST */ 548 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 549 offset); 550 m->m_data += sizeof(struct ip6_frag); 551 m->m_len -= sizeof(struct ip6_frag); 552 } else { 553 /* this comes with no copy if the boundary is on cluster */ 554 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 555 frag6_remque(q6); 556 V_frag6_nfrags -= q6->ip6q_nfrag; 557 #ifdef MAC 558 mac_ip6q_destroy(q6); 559 #endif 560 free(q6, M_FTABLE); 561 V_frag6_nfragpackets--; 562 goto dropfrag; 563 } 564 m_adj(t, sizeof(struct ip6_frag)); 565 m_cat(m, t); 566 } 567 568 /* 569 * Store NXT to the original. 570 */ 571 { 572 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 573 *prvnxtp = nxt; 574 } 575 576 frag6_remque(q6); 577 V_frag6_nfrags -= q6->ip6q_nfrag; 578 #ifdef MAC 579 mac_ip6q_reassemble(q6, m); 580 mac_ip6q_destroy(q6); 581 #endif 582 free(q6, M_FTABLE); 583 V_frag6_nfragpackets--; 584 585 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 586 int plen = 0; 587 for (t = m; t; t = t->m_next) 588 plen += t->m_len; 589 m->m_pkthdr.len = plen; 590 } 591 592 V_ip6stat.ip6s_reassembled++; 593 in6_ifstat_inc(dstifp, ifs6_reass_ok); 594 595 /* 596 * Tell launch routine the next header 597 */ 598 599 *mp = m; 600 *offp = offset; 601 602 IP6Q_UNLOCK(); 603 return nxt; 604 605 dropfrag: 606 IP6Q_UNLOCK(); 607 in6_ifstat_inc(dstifp, ifs6_reass_fail); 608 V_ip6stat.ip6s_fragdropped++; 609 m_freem(m); 610 return IPPROTO_DONE; 611 } 612 613 /* 614 * Free a fragment reassembly header and all 615 * associated datagrams. 616 */ 617 void 618 frag6_freef(struct ip6q *q6) 619 { 620 struct ip6asfrag *af6, *down6; 621 622 IP6Q_LOCK_ASSERT(); 623 624 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 625 af6 = down6) { 626 struct mbuf *m = IP6_REASS_MBUF(af6); 627 628 down6 = af6->ip6af_down; 629 frag6_deq(af6); 630 631 /* 632 * Return ICMP time exceeded error for the 1st fragment. 633 * Just free other fragments. 634 */ 635 if (af6->ip6af_off == 0) { 636 struct ip6_hdr *ip6; 637 638 /* adjust pointer */ 639 ip6 = mtod(m, struct ip6_hdr *); 640 641 /* restore source and destination addresses */ 642 ip6->ip6_src = q6->ip6q_src; 643 ip6->ip6_dst = q6->ip6q_dst; 644 645 icmp6_error(m, ICMP6_TIME_EXCEEDED, 646 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 647 } else 648 m_freem(m); 649 free(af6, M_FTABLE); 650 } 651 frag6_remque(q6); 652 V_frag6_nfrags -= q6->ip6q_nfrag; 653 #ifdef MAC 654 mac_ip6q_destroy(q6); 655 #endif 656 free(q6, M_FTABLE); 657 V_frag6_nfragpackets--; 658 } 659 660 /* 661 * Put an ip fragment on a reassembly chain. 662 * Like insque, but pointers in middle of structure. 663 */ 664 void 665 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 666 { 667 668 IP6Q_LOCK_ASSERT(); 669 670 af6->ip6af_up = up6; 671 af6->ip6af_down = up6->ip6af_down; 672 up6->ip6af_down->ip6af_up = af6; 673 up6->ip6af_down = af6; 674 } 675 676 /* 677 * To frag6_enq as remque is to insque. 678 */ 679 void 680 frag6_deq(struct ip6asfrag *af6) 681 { 682 683 IP6Q_LOCK_ASSERT(); 684 685 af6->ip6af_up->ip6af_down = af6->ip6af_down; 686 af6->ip6af_down->ip6af_up = af6->ip6af_up; 687 } 688 689 void 690 frag6_insque(struct ip6q *new, struct ip6q *old) 691 { 692 693 IP6Q_LOCK_ASSERT(); 694 695 new->ip6q_prev = old; 696 new->ip6q_next = old->ip6q_next; 697 old->ip6q_next->ip6q_prev= new; 698 old->ip6q_next = new; 699 } 700 701 void 702 frag6_remque(struct ip6q *p6) 703 { 704 705 IP6Q_LOCK_ASSERT(); 706 707 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 708 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 709 } 710 711 /* 712 * IPv6 reassembling timer processing; 713 * if a timer expires on a reassembly 714 * queue, discard it. 715 */ 716 void 717 frag6_slowtimo(void) 718 { 719 VNET_ITERATOR_DECL(vnet_iter); 720 struct ip6q *q6; 721 722 VNET_LIST_RLOCK_NOSLEEP(); 723 IP6Q_LOCK(); 724 VNET_FOREACH(vnet_iter) { 725 CURVNET_SET(vnet_iter); 726 q6 = V_ip6q.ip6q_next; 727 if (q6) 728 while (q6 != &V_ip6q) { 729 --q6->ip6q_ttl; 730 q6 = q6->ip6q_next; 731 if (q6->ip6q_prev->ip6q_ttl == 0) { 732 V_ip6stat.ip6s_fragtimeout++; 733 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 734 frag6_freef(q6->ip6q_prev); 735 } 736 } 737 /* 738 * If we are over the maximum number of fragments 739 * (due to the limit being lowered), drain off 740 * enough to get down to the new limit. 741 */ 742 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 743 V_ip6q.ip6q_prev) { 744 V_ip6stat.ip6s_fragoverflow++; 745 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 746 frag6_freef(V_ip6q.ip6q_prev); 747 } 748 CURVNET_RESTORE(); 749 } 750 IP6Q_UNLOCK(); 751 VNET_LIST_RUNLOCK_NOSLEEP(); 752 } 753 754 /* 755 * Drain off all datagram fragments. 756 */ 757 void 758 frag6_drain(void) 759 { 760 VNET_ITERATOR_DECL(vnet_iter); 761 762 VNET_LIST_RLOCK_NOSLEEP(); 763 if (IP6Q_TRYLOCK() == 0) { 764 VNET_LIST_RUNLOCK_NOSLEEP(); 765 return; 766 } 767 VNET_FOREACH(vnet_iter) { 768 CURVNET_SET(vnet_iter); 769 while (V_ip6q.ip6q_next != &V_ip6q) { 770 V_ip6stat.ip6s_fragdropped++; 771 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 772 frag6_freef(V_ip6q.ip6q_next); 773 } 774 CURVNET_RESTORE(); 775 } 776 IP6Q_UNLOCK(); 777 VNET_LIST_RUNLOCK_NOSLEEP(); 778 }
Cache object: 8ebfa50183c93897107de2037090008e
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