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/if_var.h> 49 #include <net/route.h> 50 #include <net/vnet.h> 51 52 #include <netinet/in.h> 53 #include <netinet/in_var.h> 54 #include <netinet/ip6.h> 55 #include <netinet6/ip6_var.h> 56 #include <netinet/icmp6.h> 57 #include <netinet/in_systm.h> /* for ECN definitions */ 58 #include <netinet/ip.h> /* for ECN definitions */ 59 60 #include <security/mac/mac_framework.h> 61 62 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 63 static void frag6_deq(struct ip6asfrag *); 64 static void frag6_insque(struct ip6q *, struct ip6q *); 65 static void frag6_remque(struct ip6q *); 66 static void frag6_freef(struct ip6q *); 67 68 static struct mtx ip6qlock; 69 /* 70 * These fields all protected by ip6qlock. 71 */ 72 static VNET_DEFINE(u_int, frag6_nfragpackets); 73 static VNET_DEFINE(u_int, frag6_nfrags); 74 static VNET_DEFINE(struct ip6q, ip6q); /* ip6 reassemble queue */ 75 76 #define V_frag6_nfragpackets VNET(frag6_nfragpackets) 77 #define V_frag6_nfrags VNET(frag6_nfrags) 78 #define V_ip6q VNET(ip6q) 79 80 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 81 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 82 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 83 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 84 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 85 86 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 87 88 /* 89 * Initialise reassembly queue and fragment identifier. 90 */ 91 static void 92 frag6_change(void *tag) 93 { 94 95 V_ip6_maxfragpackets = nmbclusters / 4; 96 V_ip6_maxfrags = nmbclusters / 4; 97 } 98 99 void 100 frag6_init(void) 101 { 102 103 V_ip6_maxfragpackets = nmbclusters / 4; 104 V_ip6_maxfrags = nmbclusters / 4; 105 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 106 107 if (!IS_DEFAULT_VNET(curvnet)) 108 return; 109 110 EVENTHANDLER_REGISTER(nmbclusters_change, 111 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 112 113 IP6Q_LOCK_INIT(); 114 } 115 116 /* 117 * In RFC2460, fragment and reassembly rule do not agree with each other, 118 * in terms of next header field handling in fragment header. 119 * While the sender will use the same value for all of the fragmented packets, 120 * receiver is suggested not to check the consistency. 121 * 122 * fragment rule (p20): 123 * (2) A Fragment header containing: 124 * The Next Header value that identifies the first header of 125 * the Fragmentable Part of the original packet. 126 * -> next header field is same for all fragments 127 * 128 * reassembly rule (p21): 129 * The Next Header field of the last header of the Unfragmentable 130 * Part is obtained from the Next Header field of the first 131 * fragment's Fragment header. 132 * -> should grab it from the first fragment only 133 * 134 * The following note also contradicts with fragment rule - noone is going to 135 * send different fragment with different next header field. 136 * 137 * additional note (p22): 138 * The Next Header values in the Fragment headers of different 139 * fragments of the same original packet may differ. Only the value 140 * from the Offset zero fragment packet is used for reassembly. 141 * -> should grab it from the first fragment only 142 * 143 * There is no explicit reason given in the RFC. Historical reason maybe? 144 */ 145 /* 146 * Fragment input 147 */ 148 int 149 frag6_input(struct mbuf **mp, int *offp, int proto) 150 { 151 struct mbuf *m = *mp, *t; 152 struct ip6_hdr *ip6; 153 struct ip6_frag *ip6f; 154 struct ip6q *q6; 155 struct ip6asfrag *af6, *ip6af, *af6dwn; 156 struct in6_ifaddr *ia; 157 int offset = *offp, nxt, i, next; 158 int first_frag = 0; 159 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 160 struct ifnet *dstifp; 161 u_int8_t ecn, ecn0; 162 #if 0 163 char ip6buf[INET6_ADDRSTRLEN]; 164 #endif 165 166 ip6 = mtod(m, struct ip6_hdr *); 167 #ifndef PULLDOWN_TEST 168 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 169 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 170 #else 171 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 172 if (ip6f == NULL) 173 return (IPPROTO_DONE); 174 #endif 175 176 dstifp = NULL; 177 /* find the destination interface of the packet. */ 178 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */); 179 if (ia != NULL) { 180 dstifp = ia->ia_ifp; 181 ifa_free(&ia->ia_ifa); 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_INC(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 /* 211 * RFC 6946: Handle "atomic" fragments (offset and m bit set to 0) 212 * upfront, unrelated to any reassembly. Just skip the fragment header. 213 */ 214 if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) { 215 /* XXX-BZ we want dedicated counters for this. */ 216 IP6STAT_INC(ip6s_reassembled); 217 in6_ifstat_inc(dstifp, ifs6_reass_ok); 218 *offp = offset; 219 return (ip6f->ip6f_nxt); 220 } 221 222 IP6Q_LOCK(); 223 224 /* 225 * Enforce upper bound on number of fragments. 226 * If maxfrag is 0, never accept fragments. 227 * If maxfrag is -1, accept all fragments without limitation. 228 */ 229 if (V_ip6_maxfrags < 0) 230 ; 231 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 232 goto dropfrag; 233 234 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 235 if (ip6f->ip6f_ident == q6->ip6q_ident && 236 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 237 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 238 #ifdef MAC 239 && mac_ip6q_match(m, q6) 240 #endif 241 ) 242 break; 243 244 if (q6 == &V_ip6q) { 245 /* 246 * the first fragment to arrive, create a reassembly queue. 247 */ 248 first_frag = 1; 249 250 /* 251 * Enforce upper bound on number of fragmented packets 252 * for which we attempt reassembly; 253 * If maxfragpackets is 0, never accept fragments. 254 * If maxfragpackets is -1, accept all fragments without 255 * limitation. 256 */ 257 if (V_ip6_maxfragpackets < 0) 258 ; 259 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 260 goto dropfrag; 261 V_frag6_nfragpackets++; 262 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 263 M_NOWAIT); 264 if (q6 == NULL) 265 goto dropfrag; 266 bzero(q6, sizeof(*q6)); 267 #ifdef MAC 268 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 269 free(q6, M_FTABLE); 270 goto dropfrag; 271 } 272 mac_ip6q_create(m, q6); 273 #endif 274 frag6_insque(q6, &V_ip6q); 275 276 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 277 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 278 #ifdef notyet 279 q6->ip6q_nxtp = (u_char *)nxtp; 280 #endif 281 q6->ip6q_ident = ip6f->ip6f_ident; 282 q6->ip6q_ttl = IPV6_FRAGTTL; 283 q6->ip6q_src = ip6->ip6_src; 284 q6->ip6q_dst = ip6->ip6_dst; 285 q6->ip6q_ecn = 286 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 287 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 288 289 q6->ip6q_nfrag = 0; 290 } 291 292 /* 293 * If it's the 1st fragment, record the length of the 294 * unfragmentable part and the next header of the fragment header. 295 */ 296 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 297 if (fragoff == 0) { 298 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 299 sizeof(struct ip6_frag); 300 q6->ip6q_nxt = ip6f->ip6f_nxt; 301 } 302 303 /* 304 * Check that the reassembled packet would not exceed 65535 bytes 305 * in size. 306 * If it would exceed, discard the fragment and return an ICMP error. 307 */ 308 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 309 if (q6->ip6q_unfrglen >= 0) { 310 /* The 1st fragment has already arrived. */ 311 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 312 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 313 offset - sizeof(struct ip6_frag) + 314 offsetof(struct ip6_frag, ip6f_offlg)); 315 IP6Q_UNLOCK(); 316 return (IPPROTO_DONE); 317 } 318 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 319 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 320 offset - sizeof(struct ip6_frag) + 321 offsetof(struct ip6_frag, ip6f_offlg)); 322 IP6Q_UNLOCK(); 323 return (IPPROTO_DONE); 324 } 325 /* 326 * If it's the first fragment, do the above check for each 327 * fragment already stored in the reassembly queue. 328 */ 329 if (fragoff == 0) { 330 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 331 af6 = af6dwn) { 332 af6dwn = af6->ip6af_down; 333 334 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 335 IPV6_MAXPACKET) { 336 struct mbuf *merr = IP6_REASS_MBUF(af6); 337 struct ip6_hdr *ip6err; 338 int erroff = af6->ip6af_offset; 339 340 /* dequeue the fragment. */ 341 frag6_deq(af6); 342 free(af6, M_FTABLE); 343 344 /* adjust pointer. */ 345 ip6err = mtod(merr, struct ip6_hdr *); 346 347 /* 348 * Restore source and destination addresses 349 * in the erroneous IPv6 header. 350 */ 351 ip6err->ip6_src = q6->ip6q_src; 352 ip6err->ip6_dst = q6->ip6q_dst; 353 354 icmp6_error(merr, ICMP6_PARAM_PROB, 355 ICMP6_PARAMPROB_HEADER, 356 erroff - sizeof(struct ip6_frag) + 357 offsetof(struct ip6_frag, ip6f_offlg)); 358 } 359 } 360 } 361 362 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 363 M_NOWAIT); 364 if (ip6af == NULL) 365 goto dropfrag; 366 bzero(ip6af, sizeof(*ip6af)); 367 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 368 ip6af->ip6af_off = fragoff; 369 ip6af->ip6af_frglen = frgpartlen; 370 ip6af->ip6af_offset = offset; 371 IP6_REASS_MBUF(ip6af) = m; 372 373 if (first_frag) { 374 af6 = (struct ip6asfrag *)q6; 375 goto insert; 376 } 377 378 /* 379 * Handle ECN by comparing this segment with the first one; 380 * if CE is set, do not lose CE. 381 * drop if CE and not-ECT are mixed for the same packet. 382 */ 383 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 384 ecn0 = q6->ip6q_ecn; 385 if (ecn == IPTOS_ECN_CE) { 386 if (ecn0 == IPTOS_ECN_NOTECT) { 387 free(ip6af, M_FTABLE); 388 goto dropfrag; 389 } 390 if (ecn0 != IPTOS_ECN_CE) 391 q6->ip6q_ecn = IPTOS_ECN_CE; 392 } 393 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 394 free(ip6af, M_FTABLE); 395 goto dropfrag; 396 } 397 398 /* 399 * Find a segment which begins after this one does. 400 */ 401 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 402 af6 = af6->ip6af_down) 403 if (af6->ip6af_off > ip6af->ip6af_off) 404 break; 405 406 #if 0 407 /* 408 * If there is a preceding segment, it may provide some of 409 * our data already. If so, drop the data from the incoming 410 * segment. If it provides all of our data, drop us. 411 */ 412 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 413 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 414 - ip6af->ip6af_off; 415 if (i > 0) { 416 if (i >= ip6af->ip6af_frglen) 417 goto dropfrag; 418 m_adj(IP6_REASS_MBUF(ip6af), i); 419 ip6af->ip6af_off += i; 420 ip6af->ip6af_frglen -= i; 421 } 422 } 423 424 /* 425 * While we overlap succeeding segments trim them or, 426 * if they are completely covered, dequeue them. 427 */ 428 while (af6 != (struct ip6asfrag *)q6 && 429 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 430 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 431 if (i < af6->ip6af_frglen) { 432 af6->ip6af_frglen -= i; 433 af6->ip6af_off += i; 434 m_adj(IP6_REASS_MBUF(af6), i); 435 break; 436 } 437 af6 = af6->ip6af_down; 438 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 439 frag6_deq(af6->ip6af_up); 440 } 441 #else 442 /* 443 * If the incoming framgent overlaps some existing fragments in 444 * the reassembly queue, drop it, since it is dangerous to override 445 * existing fragments from a security point of view. 446 * We don't know which fragment is the bad guy - here we trust 447 * fragment that came in earlier, with no real reason. 448 * 449 * Note: due to changes after disabling this part, mbuf passed to 450 * m_adj() below now does not meet the requirement. 451 */ 452 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 453 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 454 - ip6af->ip6af_off; 455 if (i > 0) { 456 #if 0 /* suppress the noisy log */ 457 log(LOG_ERR, "%d bytes of a fragment from %s " 458 "overlaps the previous fragment\n", 459 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 460 #endif 461 free(ip6af, M_FTABLE); 462 goto dropfrag; 463 } 464 } 465 if (af6 != (struct ip6asfrag *)q6) { 466 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 467 if (i > 0) { 468 #if 0 /* suppress the noisy log */ 469 log(LOG_ERR, "%d bytes of a fragment from %s " 470 "overlaps the succeeding fragment", 471 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 472 #endif 473 free(ip6af, M_FTABLE); 474 goto dropfrag; 475 } 476 } 477 #endif 478 479 insert: 480 #ifdef MAC 481 if (!first_frag) 482 mac_ip6q_update(m, q6); 483 #endif 484 485 /* 486 * Stick new segment in its place; 487 * check for complete reassembly. 488 * Move to front of packet queue, as we are 489 * the most recently active fragmented packet. 490 */ 491 frag6_enq(ip6af, af6->ip6af_up); 492 V_frag6_nfrags++; 493 q6->ip6q_nfrag++; 494 #if 0 /* xxx */ 495 if (q6 != V_ip6q.ip6q_next) { 496 frag6_remque(q6); 497 frag6_insque(q6, &V_ip6q); 498 } 499 #endif 500 next = 0; 501 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 502 af6 = af6->ip6af_down) { 503 if (af6->ip6af_off != next) { 504 IP6Q_UNLOCK(); 505 return IPPROTO_DONE; 506 } 507 next += af6->ip6af_frglen; 508 } 509 if (af6->ip6af_up->ip6af_mff) { 510 IP6Q_UNLOCK(); 511 return IPPROTO_DONE; 512 } 513 514 /* 515 * Reassembly is complete; concatenate fragments. 516 */ 517 ip6af = q6->ip6q_down; 518 t = m = IP6_REASS_MBUF(ip6af); 519 af6 = ip6af->ip6af_down; 520 frag6_deq(ip6af); 521 while (af6 != (struct ip6asfrag *)q6) { 522 af6dwn = af6->ip6af_down; 523 frag6_deq(af6); 524 while (t->m_next) 525 t = t->m_next; 526 t->m_next = IP6_REASS_MBUF(af6); 527 m_adj(t->m_next, af6->ip6af_offset); 528 free(af6, M_FTABLE); 529 af6 = af6dwn; 530 } 531 532 /* adjust offset to point where the original next header starts */ 533 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 534 free(ip6af, M_FTABLE); 535 ip6 = mtod(m, struct ip6_hdr *); 536 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 537 if (q6->ip6q_ecn == IPTOS_ECN_CE) 538 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 539 nxt = q6->ip6q_nxt; 540 #ifdef notyet 541 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 542 #endif 543 544 if (ip6_deletefraghdr(m, offset, M_NOWAIT) != 0) { 545 frag6_remque(q6); 546 V_frag6_nfrags -= q6->ip6q_nfrag; 547 #ifdef MAC 548 mac_ip6q_destroy(q6); 549 #endif 550 free(q6, M_FTABLE); 551 V_frag6_nfragpackets--; 552 553 goto dropfrag; 554 } 555 556 /* 557 * Store NXT to the original. 558 */ 559 { 560 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 561 *prvnxtp = nxt; 562 } 563 564 frag6_remque(q6); 565 V_frag6_nfrags -= q6->ip6q_nfrag; 566 #ifdef MAC 567 mac_ip6q_reassemble(q6, m); 568 mac_ip6q_destroy(q6); 569 #endif 570 free(q6, M_FTABLE); 571 V_frag6_nfragpackets--; 572 573 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 574 int plen = 0; 575 for (t = m; t; t = t->m_next) 576 plen += t->m_len; 577 m->m_pkthdr.len = plen; 578 } 579 580 IP6STAT_INC(ip6s_reassembled); 581 in6_ifstat_inc(dstifp, ifs6_reass_ok); 582 583 /* 584 * Tell launch routine the next header 585 */ 586 587 *mp = m; 588 *offp = offset; 589 590 IP6Q_UNLOCK(); 591 return nxt; 592 593 dropfrag: 594 IP6Q_UNLOCK(); 595 in6_ifstat_inc(dstifp, ifs6_reass_fail); 596 IP6STAT_INC(ip6s_fragdropped); 597 m_freem(m); 598 return IPPROTO_DONE; 599 } 600 601 /* 602 * Free a fragment reassembly header and all 603 * associated datagrams. 604 */ 605 void 606 frag6_freef(struct ip6q *q6) 607 { 608 struct ip6asfrag *af6, *down6; 609 610 IP6Q_LOCK_ASSERT(); 611 612 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 613 af6 = down6) { 614 struct mbuf *m = IP6_REASS_MBUF(af6); 615 616 down6 = af6->ip6af_down; 617 frag6_deq(af6); 618 619 /* 620 * Return ICMP time exceeded error for the 1st fragment. 621 * Just free other fragments. 622 */ 623 if (af6->ip6af_off == 0) { 624 struct ip6_hdr *ip6; 625 626 /* adjust pointer */ 627 ip6 = mtod(m, struct ip6_hdr *); 628 629 /* restore source and destination addresses */ 630 ip6->ip6_src = q6->ip6q_src; 631 ip6->ip6_dst = q6->ip6q_dst; 632 633 icmp6_error(m, ICMP6_TIME_EXCEEDED, 634 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 635 } else 636 m_freem(m); 637 free(af6, M_FTABLE); 638 } 639 frag6_remque(q6); 640 V_frag6_nfrags -= q6->ip6q_nfrag; 641 #ifdef MAC 642 mac_ip6q_destroy(q6); 643 #endif 644 free(q6, M_FTABLE); 645 V_frag6_nfragpackets--; 646 } 647 648 /* 649 * Put an ip fragment on a reassembly chain. 650 * Like insque, but pointers in middle of structure. 651 */ 652 void 653 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 654 { 655 656 IP6Q_LOCK_ASSERT(); 657 658 af6->ip6af_up = up6; 659 af6->ip6af_down = up6->ip6af_down; 660 up6->ip6af_down->ip6af_up = af6; 661 up6->ip6af_down = af6; 662 } 663 664 /* 665 * To frag6_enq as remque is to insque. 666 */ 667 void 668 frag6_deq(struct ip6asfrag *af6) 669 { 670 671 IP6Q_LOCK_ASSERT(); 672 673 af6->ip6af_up->ip6af_down = af6->ip6af_down; 674 af6->ip6af_down->ip6af_up = af6->ip6af_up; 675 } 676 677 void 678 frag6_insque(struct ip6q *new, struct ip6q *old) 679 { 680 681 IP6Q_LOCK_ASSERT(); 682 683 new->ip6q_prev = old; 684 new->ip6q_next = old->ip6q_next; 685 old->ip6q_next->ip6q_prev= new; 686 old->ip6q_next = new; 687 } 688 689 void 690 frag6_remque(struct ip6q *p6) 691 { 692 693 IP6Q_LOCK_ASSERT(); 694 695 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 696 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 697 } 698 699 /* 700 * IPv6 reassembling timer processing; 701 * if a timer expires on a reassembly 702 * queue, discard it. 703 */ 704 void 705 frag6_slowtimo(void) 706 { 707 VNET_ITERATOR_DECL(vnet_iter); 708 struct ip6q *q6; 709 710 VNET_LIST_RLOCK_NOSLEEP(); 711 IP6Q_LOCK(); 712 VNET_FOREACH(vnet_iter) { 713 CURVNET_SET(vnet_iter); 714 q6 = V_ip6q.ip6q_next; 715 if (q6) 716 while (q6 != &V_ip6q) { 717 --q6->ip6q_ttl; 718 q6 = q6->ip6q_next; 719 if (q6->ip6q_prev->ip6q_ttl == 0) { 720 IP6STAT_INC(ip6s_fragtimeout); 721 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 722 frag6_freef(q6->ip6q_prev); 723 } 724 } 725 /* 726 * If we are over the maximum number of fragments 727 * (due to the limit being lowered), drain off 728 * enough to get down to the new limit. 729 */ 730 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 731 V_ip6q.ip6q_prev) { 732 IP6STAT_INC(ip6s_fragoverflow); 733 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 734 frag6_freef(V_ip6q.ip6q_prev); 735 } 736 CURVNET_RESTORE(); 737 } 738 IP6Q_UNLOCK(); 739 VNET_LIST_RUNLOCK_NOSLEEP(); 740 } 741 742 /* 743 * Drain off all datagram fragments. 744 */ 745 void 746 frag6_drain(void) 747 { 748 VNET_ITERATOR_DECL(vnet_iter); 749 750 VNET_LIST_RLOCK_NOSLEEP(); 751 if (IP6Q_TRYLOCK() == 0) { 752 VNET_LIST_RUNLOCK_NOSLEEP(); 753 return; 754 } 755 VNET_FOREACH(vnet_iter) { 756 CURVNET_SET(vnet_iter); 757 while (V_ip6q.ip6q_next != &V_ip6q) { 758 IP6STAT_INC(ip6s_fragdropped); 759 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 760 frag6_freef(V_ip6q.ip6q_next); 761 } 762 CURVNET_RESTORE(); 763 } 764 IP6Q_UNLOCK(); 765 VNET_LIST_RUNLOCK_NOSLEEP(); 766 } 767 768 int 769 ip6_deletefraghdr(struct mbuf *m, int offset, int wait) 770 { 771 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 772 struct mbuf *t; 773 774 /* Delete frag6 header. */ 775 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 776 /* This is the only possible case with !PULLDOWN_TEST. */ 777 bcopy(ip6, (char *)ip6 + sizeof(struct ip6_frag), 778 offset); 779 m->m_data += sizeof(struct ip6_frag); 780 m->m_len -= sizeof(struct ip6_frag); 781 } else { 782 /* This comes with no copy if the boundary is on cluster. */ 783 if ((t = m_split(m, offset, wait)) == NULL) 784 return (ENOMEM); 785 m_adj(t, sizeof(struct ip6_frag)); 786 m_cat(m, t); 787 } 788 789 return (0); 790 } 791