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("$FreeBSD$"); 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_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 */ 154 int 155 frag6_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 IP6STAT_INC(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 * RFC 6946: Handle "atomic" fragments (offset and m bit set to 0) 226 * upfront, unrelated to any reassembly. Just skip the fragment header. 227 */ 228 if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) { 229 /* XXX-BZ we want dedicated counters for this. */ 230 IP6STAT_INC(ip6s_reassembled); 231 in6_ifstat_inc(dstifp, ifs6_reass_ok); 232 *offp = offset; 233 return (ip6f->ip6f_nxt); 234 } 235 236 IP6Q_LOCK(); 237 238 /* 239 * Enforce upper bound on number of fragments. 240 * If maxfrag is 0, never accept fragments. 241 * If maxfrag is -1, accept all fragments without limitation. 242 */ 243 if (V_ip6_maxfrags < 0) 244 ; 245 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 246 goto dropfrag; 247 248 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 249 if (ip6f->ip6f_ident == q6->ip6q_ident && 250 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 251 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 252 #ifdef MAC 253 && mac_ip6q_match(m, q6) 254 #endif 255 ) 256 break; 257 258 if (q6 == &V_ip6q) { 259 /* 260 * the first fragment to arrive, create a reassembly queue. 261 */ 262 first_frag = 1; 263 264 /* 265 * Enforce upper bound on number of fragmented packets 266 * for which we attempt reassembly; 267 * If maxfragpackets is 0, never accept fragments. 268 * If maxfragpackets is -1, accept all fragments without 269 * limitation. 270 */ 271 if (V_ip6_maxfragpackets < 0) 272 ; 273 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 274 goto dropfrag; 275 V_frag6_nfragpackets++; 276 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 277 M_NOWAIT); 278 if (q6 == NULL) 279 goto dropfrag; 280 bzero(q6, sizeof(*q6)); 281 #ifdef MAC 282 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 283 free(q6, M_FTABLE); 284 goto dropfrag; 285 } 286 mac_ip6q_create(m, q6); 287 #endif 288 frag6_insque(q6, &V_ip6q); 289 290 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 291 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 292 #ifdef notyet 293 q6->ip6q_nxtp = (u_char *)nxtp; 294 #endif 295 q6->ip6q_ident = ip6f->ip6f_ident; 296 q6->ip6q_ttl = IPV6_FRAGTTL; 297 q6->ip6q_src = ip6->ip6_src; 298 q6->ip6q_dst = ip6->ip6_dst; 299 q6->ip6q_ecn = 300 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 301 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 302 303 q6->ip6q_nfrag = 0; 304 } 305 306 /* 307 * If it's the 1st fragment, record the length of the 308 * unfragmentable part and the next header of the fragment header. 309 */ 310 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 311 if (fragoff == 0) { 312 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 313 sizeof(struct ip6_frag); 314 q6->ip6q_nxt = ip6f->ip6f_nxt; 315 } 316 317 /* 318 * Check that the reassembled packet would not exceed 65535 bytes 319 * in size. 320 * If it would exceed, discard the fragment and return an ICMP error. 321 */ 322 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 323 if (q6->ip6q_unfrglen >= 0) { 324 /* The 1st fragment has already arrived. */ 325 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 326 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 327 offset - sizeof(struct ip6_frag) + 328 offsetof(struct ip6_frag, ip6f_offlg)); 329 IP6Q_UNLOCK(); 330 return (IPPROTO_DONE); 331 } 332 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 333 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 334 offset - sizeof(struct ip6_frag) + 335 offsetof(struct ip6_frag, ip6f_offlg)); 336 IP6Q_UNLOCK(); 337 return (IPPROTO_DONE); 338 } 339 /* 340 * If it's the first fragment, do the above check for each 341 * fragment already stored in the reassembly queue. 342 */ 343 if (fragoff == 0) { 344 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 345 af6 = af6dwn) { 346 af6dwn = af6->ip6af_down; 347 348 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 349 IPV6_MAXPACKET) { 350 struct mbuf *merr = IP6_REASS_MBUF(af6); 351 struct ip6_hdr *ip6err; 352 int erroff = af6->ip6af_offset; 353 354 /* dequeue the fragment. */ 355 frag6_deq(af6); 356 free(af6, M_FTABLE); 357 358 /* adjust pointer. */ 359 ip6err = mtod(merr, struct ip6_hdr *); 360 361 /* 362 * Restore source and destination addresses 363 * in the erroneous IPv6 header. 364 */ 365 ip6err->ip6_src = q6->ip6q_src; 366 ip6err->ip6_dst = q6->ip6q_dst; 367 368 icmp6_error(merr, ICMP6_PARAM_PROB, 369 ICMP6_PARAMPROB_HEADER, 370 erroff - sizeof(struct ip6_frag) + 371 offsetof(struct ip6_frag, ip6f_offlg)); 372 } 373 } 374 } 375 376 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 377 M_NOWAIT); 378 if (ip6af == NULL) 379 goto dropfrag; 380 bzero(ip6af, sizeof(*ip6af)); 381 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 382 ip6af->ip6af_off = fragoff; 383 ip6af->ip6af_frglen = frgpartlen; 384 ip6af->ip6af_offset = offset; 385 IP6_REASS_MBUF(ip6af) = m; 386 387 if (first_frag) { 388 af6 = (struct ip6asfrag *)q6; 389 goto insert; 390 } 391 392 /* 393 * Handle ECN by comparing this segment with the first one; 394 * if CE is set, do not lose CE. 395 * drop if CE and not-ECT are mixed for the same packet. 396 */ 397 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 398 ecn0 = q6->ip6q_ecn; 399 if (ecn == IPTOS_ECN_CE) { 400 if (ecn0 == IPTOS_ECN_NOTECT) { 401 free(ip6af, M_FTABLE); 402 goto dropfrag; 403 } 404 if (ecn0 != IPTOS_ECN_CE) 405 q6->ip6q_ecn = IPTOS_ECN_CE; 406 } 407 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 408 free(ip6af, M_FTABLE); 409 goto dropfrag; 410 } 411 412 /* 413 * Find a segment which begins after this one does. 414 */ 415 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 416 af6 = af6->ip6af_down) 417 if (af6->ip6af_off > ip6af->ip6af_off) 418 break; 419 420 #if 0 421 /* 422 * If there is a preceding segment, it may provide some of 423 * our data already. If so, drop the data from the incoming 424 * segment. If it provides all of our data, drop us. 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 (i >= ip6af->ip6af_frglen) 431 goto dropfrag; 432 m_adj(IP6_REASS_MBUF(ip6af), i); 433 ip6af->ip6af_off += i; 434 ip6af->ip6af_frglen -= i; 435 } 436 } 437 438 /* 439 * While we overlap succeeding segments trim them or, 440 * if they are completely covered, dequeue them. 441 */ 442 while (af6 != (struct ip6asfrag *)q6 && 443 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 444 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 445 if (i < af6->ip6af_frglen) { 446 af6->ip6af_frglen -= i; 447 af6->ip6af_off += i; 448 m_adj(IP6_REASS_MBUF(af6), i); 449 break; 450 } 451 af6 = af6->ip6af_down; 452 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 453 frag6_deq(af6->ip6af_up); 454 } 455 #else 456 /* 457 * If the incoming framgent overlaps some existing fragments in 458 * the reassembly queue, drop it, since it is dangerous to override 459 * existing fragments from a security point of view. 460 * We don't know which fragment is the bad guy - here we trust 461 * fragment that came in earlier, with no real reason. 462 * 463 * Note: due to changes after disabling this part, mbuf passed to 464 * m_adj() below now does not meet the requirement. 465 */ 466 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 467 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 468 - ip6af->ip6af_off; 469 if (i > 0) { 470 #if 0 /* suppress the noisy log */ 471 log(LOG_ERR, "%d bytes of a fragment from %s " 472 "overlaps the previous fragment\n", 473 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 474 #endif 475 free(ip6af, M_FTABLE); 476 goto dropfrag; 477 } 478 } 479 if (af6 != (struct ip6asfrag *)q6) { 480 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 481 if (i > 0) { 482 #if 0 /* suppress the noisy log */ 483 log(LOG_ERR, "%d bytes of a fragment from %s " 484 "overlaps the succeeding fragment", 485 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 486 #endif 487 free(ip6af, M_FTABLE); 488 goto dropfrag; 489 } 490 } 491 #endif 492 493 insert: 494 #ifdef MAC 495 if (!first_frag) 496 mac_ip6q_update(m, q6); 497 #endif 498 499 /* 500 * Stick new segment in its place; 501 * check for complete reassembly. 502 * Move to front of packet queue, as we are 503 * the most recently active fragmented packet. 504 */ 505 frag6_enq(ip6af, af6->ip6af_up); 506 V_frag6_nfrags++; 507 q6->ip6q_nfrag++; 508 #if 0 /* xxx */ 509 if (q6 != V_ip6q.ip6q_next) { 510 frag6_remque(q6); 511 frag6_insque(q6, &V_ip6q); 512 } 513 #endif 514 next = 0; 515 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 516 af6 = af6->ip6af_down) { 517 if (af6->ip6af_off != next) { 518 IP6Q_UNLOCK(); 519 return IPPROTO_DONE; 520 } 521 next += af6->ip6af_frglen; 522 } 523 if (af6->ip6af_up->ip6af_mff) { 524 IP6Q_UNLOCK(); 525 return IPPROTO_DONE; 526 } 527 528 /* 529 * Reassembly is complete; concatenate fragments. 530 */ 531 ip6af = q6->ip6q_down; 532 t = m = IP6_REASS_MBUF(ip6af); 533 af6 = ip6af->ip6af_down; 534 frag6_deq(ip6af); 535 while (af6 != (struct ip6asfrag *)q6) { 536 af6dwn = af6->ip6af_down; 537 frag6_deq(af6); 538 while (t->m_next) 539 t = t->m_next; 540 t->m_next = IP6_REASS_MBUF(af6); 541 m_adj(t->m_next, af6->ip6af_offset); 542 free(af6, M_FTABLE); 543 af6 = af6dwn; 544 } 545 546 /* adjust offset to point where the original next header starts */ 547 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 548 free(ip6af, M_FTABLE); 549 ip6 = mtod(m, struct ip6_hdr *); 550 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 551 if (q6->ip6q_ecn == IPTOS_ECN_CE) 552 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 553 nxt = q6->ip6q_nxt; 554 #ifdef notyet 555 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 556 #endif 557 558 /* Delete frag6 header */ 559 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 560 /* This is the only possible case with !PULLDOWN_TEST */ 561 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 562 offset); 563 m->m_data += sizeof(struct ip6_frag); 564 m->m_len -= sizeof(struct ip6_frag); 565 } else { 566 /* this comes with no copy if the boundary is on cluster */ 567 if ((t = m_split(m, offset, M_NOWAIT)) == NULL) { 568 frag6_remque(q6); 569 V_frag6_nfrags -= q6->ip6q_nfrag; 570 #ifdef MAC 571 mac_ip6q_destroy(q6); 572 #endif 573 free(q6, M_FTABLE); 574 V_frag6_nfragpackets--; 575 goto dropfrag; 576 } 577 m_adj(t, sizeof(struct ip6_frag)); 578 m_cat(m, t); 579 } 580 581 /* 582 * Store NXT to the original. 583 */ 584 { 585 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 586 *prvnxtp = nxt; 587 } 588 589 frag6_remque(q6); 590 V_frag6_nfrags -= q6->ip6q_nfrag; 591 #ifdef MAC 592 mac_ip6q_reassemble(q6, m); 593 mac_ip6q_destroy(q6); 594 #endif 595 free(q6, M_FTABLE); 596 V_frag6_nfragpackets--; 597 598 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 599 int plen = 0; 600 for (t = m; t; t = t->m_next) 601 plen += t->m_len; 602 m->m_pkthdr.len = plen; 603 } 604 605 IP6STAT_INC(ip6s_reassembled); 606 in6_ifstat_inc(dstifp, ifs6_reass_ok); 607 608 /* 609 * Tell launch routine the next header 610 */ 611 612 *mp = m; 613 *offp = offset; 614 615 IP6Q_UNLOCK(); 616 return nxt; 617 618 dropfrag: 619 IP6Q_UNLOCK(); 620 in6_ifstat_inc(dstifp, ifs6_reass_fail); 621 IP6STAT_INC(ip6s_fragdropped); 622 m_freem(m); 623 return IPPROTO_DONE; 624 } 625 626 /* 627 * Free a fragment reassembly header and all 628 * associated datagrams. 629 */ 630 void 631 frag6_freef(struct ip6q *q6) 632 { 633 struct ip6asfrag *af6, *down6; 634 635 IP6Q_LOCK_ASSERT(); 636 637 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 638 af6 = down6) { 639 struct mbuf *m = IP6_REASS_MBUF(af6); 640 641 down6 = af6->ip6af_down; 642 frag6_deq(af6); 643 644 /* 645 * Return ICMP time exceeded error for the 1st fragment. 646 * Just free other fragments. 647 */ 648 if (af6->ip6af_off == 0) { 649 struct ip6_hdr *ip6; 650 651 /* adjust pointer */ 652 ip6 = mtod(m, struct ip6_hdr *); 653 654 /* restore source and destination addresses */ 655 ip6->ip6_src = q6->ip6q_src; 656 ip6->ip6_dst = q6->ip6q_dst; 657 658 icmp6_error(m, ICMP6_TIME_EXCEEDED, 659 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 660 } else 661 m_freem(m); 662 free(af6, M_FTABLE); 663 } 664 frag6_remque(q6); 665 V_frag6_nfrags -= q6->ip6q_nfrag; 666 #ifdef MAC 667 mac_ip6q_destroy(q6); 668 #endif 669 free(q6, M_FTABLE); 670 V_frag6_nfragpackets--; 671 } 672 673 /* 674 * Put an ip fragment on a reassembly chain. 675 * Like insque, but pointers in middle of structure. 676 */ 677 void 678 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 679 { 680 681 IP6Q_LOCK_ASSERT(); 682 683 af6->ip6af_up = up6; 684 af6->ip6af_down = up6->ip6af_down; 685 up6->ip6af_down->ip6af_up = af6; 686 up6->ip6af_down = af6; 687 } 688 689 /* 690 * To frag6_enq as remque is to insque. 691 */ 692 void 693 frag6_deq(struct ip6asfrag *af6) 694 { 695 696 IP6Q_LOCK_ASSERT(); 697 698 af6->ip6af_up->ip6af_down = af6->ip6af_down; 699 af6->ip6af_down->ip6af_up = af6->ip6af_up; 700 } 701 702 void 703 frag6_insque(struct ip6q *new, struct ip6q *old) 704 { 705 706 IP6Q_LOCK_ASSERT(); 707 708 new->ip6q_prev = old; 709 new->ip6q_next = old->ip6q_next; 710 old->ip6q_next->ip6q_prev= new; 711 old->ip6q_next = new; 712 } 713 714 void 715 frag6_remque(struct ip6q *p6) 716 { 717 718 IP6Q_LOCK_ASSERT(); 719 720 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 721 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 722 } 723 724 /* 725 * IPv6 reassembling timer processing; 726 * if a timer expires on a reassembly 727 * queue, discard it. 728 */ 729 void 730 frag6_slowtimo(void) 731 { 732 VNET_ITERATOR_DECL(vnet_iter); 733 struct ip6q *q6; 734 735 VNET_LIST_RLOCK_NOSLEEP(); 736 IP6Q_LOCK(); 737 VNET_FOREACH(vnet_iter) { 738 CURVNET_SET(vnet_iter); 739 q6 = V_ip6q.ip6q_next; 740 if (q6) 741 while (q6 != &V_ip6q) { 742 --q6->ip6q_ttl; 743 q6 = q6->ip6q_next; 744 if (q6->ip6q_prev->ip6q_ttl == 0) { 745 IP6STAT_INC(ip6s_fragtimeout); 746 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 747 frag6_freef(q6->ip6q_prev); 748 } 749 } 750 /* 751 * If we are over the maximum number of fragments 752 * (due to the limit being lowered), drain off 753 * enough to get down to the new limit. 754 */ 755 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 756 V_ip6q.ip6q_prev) { 757 IP6STAT_INC(ip6s_fragoverflow); 758 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 759 frag6_freef(V_ip6q.ip6q_prev); 760 } 761 CURVNET_RESTORE(); 762 } 763 IP6Q_UNLOCK(); 764 VNET_LIST_RUNLOCK_NOSLEEP(); 765 } 766 767 /* 768 * Drain off all datagram fragments. 769 */ 770 void 771 frag6_drain(void) 772 { 773 VNET_ITERATOR_DECL(vnet_iter); 774 775 VNET_LIST_RLOCK_NOSLEEP(); 776 if (IP6Q_TRYLOCK() == 0) { 777 VNET_LIST_RUNLOCK_NOSLEEP(); 778 return; 779 } 780 VNET_FOREACH(vnet_iter) { 781 CURVNET_SET(vnet_iter); 782 while (V_ip6q.ip6q_next != &V_ip6q) { 783 IP6STAT_INC(ip6s_fragdropped); 784 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 785 frag6_freef(V_ip6q.ip6q_next); 786 } 787 CURVNET_RESTORE(); 788 } 789 IP6Q_UNLOCK(); 790 VNET_LIST_RUNLOCK_NOSLEEP(); 791 } 792