frag6.c revision 238248
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: head/sys/netinet6/frag6.c 238248 2012-07-08 15:30:24Z bz $"); 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 68static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 69static void frag6_deq(struct ip6asfrag *); 70static void frag6_insque(struct ip6q *, struct ip6q *); 71static void frag6_remque(struct ip6q *); 72static void frag6_freef(struct ip6q *); 73 74static struct mtx ip6qlock; 75/* 76 * These fields all protected by ip6qlock. 77 */ 78static VNET_DEFINE(u_int, frag6_nfragpackets); 79static VNET_DEFINE(u_int, frag6_nfrags); 80static 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 92static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 93 94/* 95 * Initialise reassembly queue and fragment identifier. 96 */ 97static void 98frag6_change(void *tag) 99{ 100 101 V_ip6_maxfragpackets = nmbclusters / 4; 102 V_ip6_maxfrags = nmbclusters / 4; 103} 104 105void 106frag6_init(void) 107{ 108 109 V_ip6_maxfragpackets = nmbclusters / 4; 110 V_ip6_maxfrags = nmbclusters / 4; 111 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 112 113 if (!IS_DEFAULT_VNET(curvnet)) 114 return; 115 116 EVENTHANDLER_REGISTER(nmbclusters_change, 117 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 118 119 IP6Q_LOCK_INIT(); 120} 121 122/* 123 * In RFC2460, fragment and reassembly rule do not agree with each other, 124 * in terms of next header field handling in fragment header. 125 * While the sender will use the same value for all of the fragmented packets, 126 * receiver is suggested not to check the consistency. 127 * 128 * fragment rule (p20): 129 * (2) A Fragment header containing: 130 * The Next Header value that identifies the first header of 131 * the Fragmentable Part of the original packet. 132 * -> next header field is same for all fragments 133 * 134 * reassembly rule (p21): 135 * The Next Header field of the last header of the Unfragmentable 136 * Part is obtained from the Next Header field of the first 137 * fragment's Fragment header. 138 * -> should grab it from the first fragment only 139 * 140 * The following note also contradicts with fragment rule - noone is going to 141 * send different fragment with different next header field. 142 * 143 * additional note (p22): 144 * The Next Header values in the Fragment headers of different 145 * fragments of the same original packet may differ. Only the value 146 * from the Offset zero fragment packet is used for reassembly. 147 * -> should grab it from the first fragment only 148 * 149 * There is no explicit reason given in the RFC. Historical reason maybe? 150 */ 151/* 152 * Fragment input 153 */ 154int 155frag6_input(struct mbuf **mp, int *offp, int proto) 156{ 157 struct mbuf *m = *mp, *t; 158 struct ip6_hdr *ip6; 159 struct ip6_frag *ip6f; 160 struct ip6q *q6; 161 struct ip6asfrag *af6, *ip6af, *af6dwn; 162#ifdef IN6_IFSTAT_STRICT 163 struct in6_ifaddr *ia; 164#endif 165 int offset = *offp, nxt, i, next; 166 int first_frag = 0; 167 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 168 struct ifnet *dstifp; 169 u_int8_t ecn, ecn0; 170#if 0 171 char ip6buf[INET6_ADDRSTRLEN]; 172#endif 173 174 ip6 = mtod(m, struct ip6_hdr *); 175#ifndef PULLDOWN_TEST 176 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 177 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 178#else 179 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 180 if (ip6f == NULL) 181 return (IPPROTO_DONE); 182#endif 183 184 dstifp = NULL; 185#ifdef IN6_IFSTAT_STRICT 186 /* find the destination interface of the packet. */ 187 if ((ia = ip6_getdstifaddr(m)) != NULL) { 188 dstifp = ia->ia_ifp; 189 ifa_free(&ia->ia_ifa); 190 } 191#else 192 /* we are violating the spec, this is not the destination interface */ 193 if ((m->m_flags & M_PKTHDR) != 0) 194 dstifp = m->m_pkthdr.rcvif; 195#endif 196 197 /* jumbo payload can't contain a fragment header */ 198 if (ip6->ip6_plen == 0) { 199 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 200 in6_ifstat_inc(dstifp, ifs6_reass_fail); 201 return IPPROTO_DONE; 202 } 203 204 /* 205 * check whether fragment packet's fragment length is 206 * multiple of 8 octets. 207 * sizeof(struct ip6_frag) == 8 208 * sizeof(struct ip6_hdr) = 40 209 */ 210 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 211 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 212 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 213 offsetof(struct ip6_hdr, ip6_plen)); 214 in6_ifstat_inc(dstifp, ifs6_reass_fail); 215 return IPPROTO_DONE; 216 } 217 218 V_ip6stat.ip6s_fragments++; 219 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 220 221 /* offset now points to data portion */ 222 offset += sizeof(struct ip6_frag); 223 224 /* 225 * XXX-BZ RFC XXXX (draft-gont-6man-ipv6-atomic-fragments) 226 * Handle "atomic" fragments (offset and m bit set to 0) upfront, 227 * unrelated to any reassembly. Just skip the fragment header. 228 */ 229 if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) { 230 /* XXX-BZ we want dedicated counters for this. */ 231 V_ip6stat.ip6s_reassembled++; 232 in6_ifstat_inc(dstifp, ifs6_reass_ok); 233 *offp = offset; 234 return (ip6f->ip6f_nxt); 235 } 236 237 IP6Q_LOCK(); 238 239 /* 240 * Enforce upper bound on number of fragments. 241 * If maxfrag is 0, never accept fragments. 242 * If maxfrag is -1, accept all fragments without limitation. 243 */ 244 if (V_ip6_maxfrags < 0) 245 ; 246 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 247 goto dropfrag; 248 249 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 250 if (ip6f->ip6f_ident == q6->ip6q_ident && 251 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 252 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 253#ifdef MAC 254 && mac_ip6q_match(m, q6) 255#endif 256 ) 257 break; 258 259 if (q6 == &V_ip6q) { 260 /* 261 * the first fragment to arrive, create a reassembly queue. 262 */ 263 first_frag = 1; 264 265 /* 266 * Enforce upper bound on number of fragmented packets 267 * for which we attempt reassembly; 268 * If maxfragpackets is 0, never accept fragments. 269 * If maxfragpackets is -1, accept all fragments without 270 * limitation. 271 */ 272 if (V_ip6_maxfragpackets < 0) 273 ; 274 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 275 goto dropfrag; 276 V_frag6_nfragpackets++; 277 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 278 M_NOWAIT); 279 if (q6 == NULL) 280 goto dropfrag; 281 bzero(q6, sizeof(*q6)); 282#ifdef MAC 283 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 284 free(q6, M_FTABLE); 285 goto dropfrag; 286 } 287 mac_ip6q_create(m, q6); 288#endif 289 frag6_insque(q6, &V_ip6q); 290 291 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 292 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 293#ifdef notyet 294 q6->ip6q_nxtp = (u_char *)nxtp; 295#endif 296 q6->ip6q_ident = ip6f->ip6f_ident; 297 q6->ip6q_ttl = IPV6_FRAGTTL; 298 q6->ip6q_src = ip6->ip6_src; 299 q6->ip6q_dst = ip6->ip6_dst; 300 q6->ip6q_ecn = 301 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 302 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 303 304 q6->ip6q_nfrag = 0; 305 } 306 307 /* 308 * If it's the 1st fragment, record the length of the 309 * unfragmentable part and the next header of the fragment header. 310 */ 311 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 312 if (fragoff == 0) { 313 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 314 sizeof(struct ip6_frag); 315 q6->ip6q_nxt = ip6f->ip6f_nxt; 316 } 317 318 /* 319 * Check that the reassembled packet would not exceed 65535 bytes 320 * in size. 321 * If it would exceed, discard the fragment and return an ICMP error. 322 */ 323 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 324 if (q6->ip6q_unfrglen >= 0) { 325 /* The 1st fragment has already arrived. */ 326 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 327 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 328 offset - sizeof(struct ip6_frag) + 329 offsetof(struct ip6_frag, ip6f_offlg)); 330 IP6Q_UNLOCK(); 331 return (IPPROTO_DONE); 332 } 333 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 334 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 335 offset - sizeof(struct ip6_frag) + 336 offsetof(struct ip6_frag, ip6f_offlg)); 337 IP6Q_UNLOCK(); 338 return (IPPROTO_DONE); 339 } 340 /* 341 * If it's the first fragment, do the above check for each 342 * fragment already stored in the reassembly queue. 343 */ 344 if (fragoff == 0) { 345 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 346 af6 = af6dwn) { 347 af6dwn = af6->ip6af_down; 348 349 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 350 IPV6_MAXPACKET) { 351 struct mbuf *merr = IP6_REASS_MBUF(af6); 352 struct ip6_hdr *ip6err; 353 int erroff = af6->ip6af_offset; 354 355 /* dequeue the fragment. */ 356 frag6_deq(af6); 357 free(af6, M_FTABLE); 358 359 /* adjust pointer. */ 360 ip6err = mtod(merr, struct ip6_hdr *); 361 362 /* 363 * Restore source and destination addresses 364 * in the erroneous IPv6 header. 365 */ 366 ip6err->ip6_src = q6->ip6q_src; 367 ip6err->ip6_dst = q6->ip6q_dst; 368 369 icmp6_error(merr, ICMP6_PARAM_PROB, 370 ICMP6_PARAMPROB_HEADER, 371 erroff - sizeof(struct ip6_frag) + 372 offsetof(struct ip6_frag, ip6f_offlg)); 373 } 374 } 375 } 376 377 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 378 M_NOWAIT); 379 if (ip6af == NULL) 380 goto dropfrag; 381 bzero(ip6af, sizeof(*ip6af)); 382 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 383 ip6af->ip6af_off = fragoff; 384 ip6af->ip6af_frglen = frgpartlen; 385 ip6af->ip6af_offset = offset; 386 IP6_REASS_MBUF(ip6af) = m; 387 388 if (first_frag) { 389 af6 = (struct ip6asfrag *)q6; 390 goto insert; 391 } 392 393 /* 394 * Handle ECN by comparing this segment with the first one; 395 * if CE is set, do not lose CE. 396 * drop if CE and not-ECT are mixed for the same packet. 397 */ 398 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 399 ecn0 = q6->ip6q_ecn; 400 if (ecn == IPTOS_ECN_CE) { 401 if (ecn0 == IPTOS_ECN_NOTECT) { 402 free(ip6af, M_FTABLE); 403 goto dropfrag; 404 } 405 if (ecn0 != IPTOS_ECN_CE) 406 q6->ip6q_ecn = IPTOS_ECN_CE; 407 } 408 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 409 free(ip6af, M_FTABLE); 410 goto dropfrag; 411 } 412 413 /* 414 * Find a segment which begins after this one does. 415 */ 416 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 417 af6 = af6->ip6af_down) 418 if (af6->ip6af_off > ip6af->ip6af_off) 419 break; 420 421#if 0 422 /* 423 * If there is a preceding segment, it may provide some of 424 * our data already. If so, drop the data from the incoming 425 * segment. If it provides all of our data, drop us. 426 */ 427 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 428 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 429 - ip6af->ip6af_off; 430 if (i > 0) { 431 if (i >= ip6af->ip6af_frglen) 432 goto dropfrag; 433 m_adj(IP6_REASS_MBUF(ip6af), i); 434 ip6af->ip6af_off += i; 435 ip6af->ip6af_frglen -= i; 436 } 437 } 438 439 /* 440 * While we overlap succeeding segments trim them or, 441 * if they are completely covered, dequeue them. 442 */ 443 while (af6 != (struct ip6asfrag *)q6 && 444 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 445 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 446 if (i < af6->ip6af_frglen) { 447 af6->ip6af_frglen -= i; 448 af6->ip6af_off += i; 449 m_adj(IP6_REASS_MBUF(af6), i); 450 break; 451 } 452 af6 = af6->ip6af_down; 453 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 454 frag6_deq(af6->ip6af_up); 455 } 456#else 457 /* 458 * If the incoming framgent overlaps some existing fragments in 459 * the reassembly queue, drop it, since it is dangerous to override 460 * existing fragments from a security point of view. 461 * We don't know which fragment is the bad guy - here we trust 462 * fragment that came in earlier, with no real reason. 463 * 464 * Note: due to changes after disabling this part, mbuf passed to 465 * m_adj() below now does not meet the requirement. 466 */ 467 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 468 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 469 - ip6af->ip6af_off; 470 if (i > 0) { 471#if 0 /* suppress the noisy log */ 472 log(LOG_ERR, "%d bytes of a fragment from %s " 473 "overlaps the previous fragment\n", 474 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 475#endif 476 free(ip6af, M_FTABLE); 477 goto dropfrag; 478 } 479 } 480 if (af6 != (struct ip6asfrag *)q6) { 481 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 482 if (i > 0) { 483#if 0 /* suppress the noisy log */ 484 log(LOG_ERR, "%d bytes of a fragment from %s " 485 "overlaps the succeeding fragment", 486 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 487#endif 488 free(ip6af, M_FTABLE); 489 goto dropfrag; 490 } 491 } 492#endif 493 494insert: 495#ifdef MAC 496 if (!first_frag) 497 mac_ip6q_update(m, q6); 498#endif 499 500 /* 501 * Stick new segment in its place; 502 * check for complete reassembly. 503 * Move to front of packet queue, as we are 504 * the most recently active fragmented packet. 505 */ 506 frag6_enq(ip6af, af6->ip6af_up); 507 V_frag6_nfrags++; 508 q6->ip6q_nfrag++; 509#if 0 /* xxx */ 510 if (q6 != V_ip6q.ip6q_next) { 511 frag6_remque(q6); 512 frag6_insque(q6, &V_ip6q); 513 } 514#endif 515 next = 0; 516 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 517 af6 = af6->ip6af_down) { 518 if (af6->ip6af_off != next) { 519 IP6Q_UNLOCK(); 520 return IPPROTO_DONE; 521 } 522 next += af6->ip6af_frglen; 523 } 524 if (af6->ip6af_up->ip6af_mff) { 525 IP6Q_UNLOCK(); 526 return IPPROTO_DONE; 527 } 528 529 /* 530 * Reassembly is complete; concatenate fragments. 531 */ 532 ip6af = q6->ip6q_down; 533 t = m = IP6_REASS_MBUF(ip6af); 534 af6 = ip6af->ip6af_down; 535 frag6_deq(ip6af); 536 while (af6 != (struct ip6asfrag *)q6) { 537 af6dwn = af6->ip6af_down; 538 frag6_deq(af6); 539 while (t->m_next) 540 t = t->m_next; 541 t->m_next = IP6_REASS_MBUF(af6); 542 m_adj(t->m_next, af6->ip6af_offset); 543 free(af6, M_FTABLE); 544 af6 = af6dwn; 545 } 546 547 /* adjust offset to point where the original next header starts */ 548 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 549 free(ip6af, M_FTABLE); 550 ip6 = mtod(m, struct ip6_hdr *); 551 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 552 if (q6->ip6q_ecn == IPTOS_ECN_CE) 553 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 554 nxt = q6->ip6q_nxt; 555#ifdef notyet 556 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 557#endif 558 559 /* Delete frag6 header */ 560 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 561 /* This is the only possible case with !PULLDOWN_TEST */ 562 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 563 offset); 564 m->m_data += sizeof(struct ip6_frag); 565 m->m_len -= sizeof(struct ip6_frag); 566 } else { 567 /* this comes with no copy if the boundary is on cluster */ 568 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 569 frag6_remque(q6); 570 V_frag6_nfrags -= q6->ip6q_nfrag; 571#ifdef MAC 572 mac_ip6q_destroy(q6); 573#endif 574 free(q6, M_FTABLE); 575 V_frag6_nfragpackets--; 576 goto dropfrag; 577 } 578 m_adj(t, sizeof(struct ip6_frag)); 579 m_cat(m, t); 580 } 581 582 /* 583 * Store NXT to the original. 584 */ 585 { 586 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 587 *prvnxtp = nxt; 588 } 589 590 frag6_remque(q6); 591 V_frag6_nfrags -= q6->ip6q_nfrag; 592#ifdef MAC 593 mac_ip6q_reassemble(q6, m); 594 mac_ip6q_destroy(q6); 595#endif 596 free(q6, M_FTABLE); 597 V_frag6_nfragpackets--; 598 599 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 600 int plen = 0; 601 for (t = m; t; t = t->m_next) 602 plen += t->m_len; 603 m->m_pkthdr.len = plen; 604 } 605 606 V_ip6stat.ip6s_reassembled++; 607 in6_ifstat_inc(dstifp, ifs6_reass_ok); 608 609 /* 610 * Tell launch routine the next header 611 */ 612 613 *mp = m; 614 *offp = offset; 615 616 IP6Q_UNLOCK(); 617 return nxt; 618 619 dropfrag: 620 IP6Q_UNLOCK(); 621 in6_ifstat_inc(dstifp, ifs6_reass_fail); 622 V_ip6stat.ip6s_fragdropped++; 623 m_freem(m); 624 return IPPROTO_DONE; 625} 626 627/* 628 * Free a fragment reassembly header and all 629 * associated datagrams. 630 */ 631void 632frag6_freef(struct ip6q *q6) 633{ 634 struct ip6asfrag *af6, *down6; 635 636 IP6Q_LOCK_ASSERT(); 637 638 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 639 af6 = down6) { 640 struct mbuf *m = IP6_REASS_MBUF(af6); 641 642 down6 = af6->ip6af_down; 643 frag6_deq(af6); 644 645 /* 646 * Return ICMP time exceeded error for the 1st fragment. 647 * Just free other fragments. 648 */ 649 if (af6->ip6af_off == 0) { 650 struct ip6_hdr *ip6; 651 652 /* adjust pointer */ 653 ip6 = mtod(m, struct ip6_hdr *); 654 655 /* restore source and destination addresses */ 656 ip6->ip6_src = q6->ip6q_src; 657 ip6->ip6_dst = q6->ip6q_dst; 658 659 icmp6_error(m, ICMP6_TIME_EXCEEDED, 660 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 661 } else 662 m_freem(m); 663 free(af6, M_FTABLE); 664 } 665 frag6_remque(q6); 666 V_frag6_nfrags -= q6->ip6q_nfrag; 667#ifdef MAC 668 mac_ip6q_destroy(q6); 669#endif 670 free(q6, M_FTABLE); 671 V_frag6_nfragpackets--; 672} 673 674/* 675 * Put an ip fragment on a reassembly chain. 676 * Like insque, but pointers in middle of structure. 677 */ 678void 679frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 680{ 681 682 IP6Q_LOCK_ASSERT(); 683 684 af6->ip6af_up = up6; 685 af6->ip6af_down = up6->ip6af_down; 686 up6->ip6af_down->ip6af_up = af6; 687 up6->ip6af_down = af6; 688} 689 690/* 691 * To frag6_enq as remque is to insque. 692 */ 693void 694frag6_deq(struct ip6asfrag *af6) 695{ 696 697 IP6Q_LOCK_ASSERT(); 698 699 af6->ip6af_up->ip6af_down = af6->ip6af_down; 700 af6->ip6af_down->ip6af_up = af6->ip6af_up; 701} 702 703void 704frag6_insque(struct ip6q *new, struct ip6q *old) 705{ 706 707 IP6Q_LOCK_ASSERT(); 708 709 new->ip6q_prev = old; 710 new->ip6q_next = old->ip6q_next; 711 old->ip6q_next->ip6q_prev= new; 712 old->ip6q_next = new; 713} 714 715void 716frag6_remque(struct ip6q *p6) 717{ 718 719 IP6Q_LOCK_ASSERT(); 720 721 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 722 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 723} 724 725/* 726 * IPv6 reassembling timer processing; 727 * if a timer expires on a reassembly 728 * queue, discard it. 729 */ 730void 731frag6_slowtimo(void) 732{ 733 VNET_ITERATOR_DECL(vnet_iter); 734 struct ip6q *q6; 735 736 VNET_LIST_RLOCK_NOSLEEP(); 737 IP6Q_LOCK(); 738 VNET_FOREACH(vnet_iter) { 739 CURVNET_SET(vnet_iter); 740 q6 = V_ip6q.ip6q_next; 741 if (q6) 742 while (q6 != &V_ip6q) { 743 --q6->ip6q_ttl; 744 q6 = q6->ip6q_next; 745 if (q6->ip6q_prev->ip6q_ttl == 0) { 746 V_ip6stat.ip6s_fragtimeout++; 747 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 748 frag6_freef(q6->ip6q_prev); 749 } 750 } 751 /* 752 * If we are over the maximum number of fragments 753 * (due to the limit being lowered), drain off 754 * enough to get down to the new limit. 755 */ 756 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 757 V_ip6q.ip6q_prev) { 758 V_ip6stat.ip6s_fragoverflow++; 759 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 760 frag6_freef(V_ip6q.ip6q_prev); 761 } 762 CURVNET_RESTORE(); 763 } 764 IP6Q_UNLOCK(); 765 VNET_LIST_RUNLOCK_NOSLEEP(); 766} 767 768/* 769 * Drain off all datagram fragments. 770 */ 771void 772frag6_drain(void) 773{ 774 VNET_ITERATOR_DECL(vnet_iter); 775 776 VNET_LIST_RLOCK_NOSLEEP(); 777 if (IP6Q_TRYLOCK() == 0) { 778 VNET_LIST_RUNLOCK_NOSLEEP(); 779 return; 780 } 781 VNET_FOREACH(vnet_iter) { 782 CURVNET_SET(vnet_iter); 783 while (V_ip6q.ip6q_next != &V_ip6q) { 784 V_ip6stat.ip6s_fragdropped++; 785 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 786 frag6_freef(V_ip6q.ip6q_next); 787 } 788 CURVNET_RESTORE(); 789 } 790 IP6Q_UNLOCK(); 791 VNET_LIST_RUNLOCK_NOSLEEP(); 792} 793