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 "opt_mac.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/domain.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/errno.h> 45 #include <sys/time.h> 46 #include <sys/kernel.h> 47 #include <sys/syslog.h> 48 #include <sys/vimage.h> 49 50 #include <net/if.h> 51 #include <net/route.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_var.h> 55 #include <netinet/ip6.h> 56 #include <netinet6/ip6_var.h> 57 #include <netinet/icmp6.h> 58 #include <netinet/in_systm.h> /* for ECN definitions */ 59 #include <netinet/ip.h> /* for ECN definitions */ 60 61 #include <security/mac/mac_framework.h> 62 63 /* 64 * Define it to get a correct behavior on per-interface statistics. 65 * You will need to perform an extra routing table lookup, per fragment, 66 * to do it. This may, or may not be, a performance hit. 67 */ 68 #define IN6_IFSTAT_STRICT 69 70 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 71 static void frag6_deq(struct ip6asfrag *); 72 static void frag6_insque(struct ip6q *, struct ip6q *); 73 static void frag6_remque(struct ip6q *); 74 static void frag6_freef(struct ip6q *); 75 76 static struct mtx ip6qlock; 77 /* 78 * These fields all protected by ip6qlock. 79 */ 80 #ifdef VIMAGE_GLOBALS 81 static u_int frag6_nfragpackets; 82 static u_int frag6_nfrags; 83 static struct ip6q ip6q; /* ip6 reassemble queue */ 84 #endif 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 INIT_VNET_INET6(curvnet); 101 102 V_ip6_maxfragpackets = nmbclusters / 4; 103 V_ip6_maxfrags = nmbclusters / 4; 104 } 105 106 void 107 frag6_init(void) 108 { 109 INIT_VNET_INET6(curvnet); 110 111 V_ip6_maxfragpackets = nmbclusters / 4; 112 V_ip6_maxfrags = nmbclusters / 4; 113 EVENTHANDLER_REGISTER(nmbclusters_change, 114 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 115 116 IP6Q_LOCK_INIT(); 117 118 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 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 INIT_VNET_INET6(curvnet); 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 #else 190 /* we are violating the spec, this is not the destination interface */ 191 if ((m->m_flags & M_PKTHDR) != 0) 192 dstifp = m->m_pkthdr.rcvif; 193 #endif 194 195 /* jumbo payload can't contain a fragment header */ 196 if (ip6->ip6_plen == 0) { 197 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 198 in6_ifstat_inc(dstifp, ifs6_reass_fail); 199 return IPPROTO_DONE; 200 } 201 202 /* 203 * check whether fragment packet's fragment length is 204 * multiple of 8 octets. 205 * sizeof(struct ip6_frag) == 8 206 * sizeof(struct ip6_hdr) = 40 207 */ 208 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 209 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 210 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 211 offsetof(struct ip6_hdr, ip6_plen)); 212 in6_ifstat_inc(dstifp, ifs6_reass_fail); 213 return IPPROTO_DONE; 214 } 215 216 V_ip6stat.ip6s_fragments++; 217 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 218 219 /* offset now points to data portion */ 220 offset += sizeof(struct ip6_frag); 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 /* Delete frag6 header */ 545 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 546 /* This is the only possible case with !PULLDOWN_TEST */ 547 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 548 offset); 549 m->m_data += sizeof(struct ip6_frag); 550 m->m_len -= sizeof(struct ip6_frag); 551 } else { 552 /* this comes with no copy if the boundary is on cluster */ 553 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 554 frag6_remque(q6); 555 V_frag6_nfrags -= q6->ip6q_nfrag; 556 #ifdef MAC 557 mac_ip6q_destroy(q6); 558 #endif 559 free(q6, M_FTABLE); 560 V_frag6_nfragpackets--; 561 goto dropfrag; 562 } 563 m_adj(t, sizeof(struct ip6_frag)); 564 m_cat(m, t); 565 } 566 567 /* 568 * Store NXT to the original. 569 */ 570 { 571 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 572 *prvnxtp = nxt; 573 } 574 575 frag6_remque(q6); 576 V_frag6_nfrags -= q6->ip6q_nfrag; 577 #ifdef MAC 578 mac_ip6q_reassemble(q6, m); 579 mac_ip6q_destroy(q6); 580 #endif 581 free(q6, M_FTABLE); 582 V_frag6_nfragpackets--; 583 584 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 585 int plen = 0; 586 for (t = m; t; t = t->m_next) 587 plen += t->m_len; 588 m->m_pkthdr.len = plen; 589 } 590 591 V_ip6stat.ip6s_reassembled++; 592 in6_ifstat_inc(dstifp, ifs6_reass_ok); 593 594 /* 595 * Tell launch routine the next header 596 */ 597 598 *mp = m; 599 *offp = offset; 600 601 IP6Q_UNLOCK(); 602 return nxt; 603 604 dropfrag: 605 IP6Q_UNLOCK(); 606 in6_ifstat_inc(dstifp, ifs6_reass_fail); 607 V_ip6stat.ip6s_fragdropped++; 608 m_freem(m); 609 return IPPROTO_DONE; 610 } 611 612 /* 613 * Free a fragment reassembly header and all 614 * associated datagrams. 615 */ 616 void 617 frag6_freef(struct ip6q *q6) 618 { 619 INIT_VNET_INET6(curvnet); 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 IP6Q_LOCK(); 723 VNET_LIST_RLOCK(); 724 VNET_FOREACH(vnet_iter) { 725 CURVNET_SET(vnet_iter); 726 INIT_VNET_INET6(vnet_iter); 727 q6 = V_ip6q.ip6q_next; 728 if (q6) 729 while (q6 != &V_ip6q) { 730 --q6->ip6q_ttl; 731 q6 = q6->ip6q_next; 732 if (q6->ip6q_prev->ip6q_ttl == 0) { 733 V_ip6stat.ip6s_fragtimeout++; 734 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 735 frag6_freef(q6->ip6q_prev); 736 } 737 } 738 /* 739 * If we are over the maximum number of fragments 740 * (due to the limit being lowered), drain off 741 * enough to get down to the new limit. 742 */ 743 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 744 V_ip6q.ip6q_prev) { 745 V_ip6stat.ip6s_fragoverflow++; 746 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 747 frag6_freef(V_ip6q.ip6q_prev); 748 } 749 CURVNET_RESTORE(); 750 } 751 VNET_LIST_RUNLOCK(); 752 IP6Q_UNLOCK(); 753 754 #if 0 755 /* 756 * Routing changes might produce a better route than we last used; 757 * make sure we notice eventually, even if forwarding only for one 758 * destination and the cache is never replaced. 759 */ 760 if (V_ip6_forward_rt.ro_rt) { 761 RTFREE(V_ip6_forward_rt.ro_rt); 762 V_ip6_forward_rt.ro_rt = 0; 763 } 764 if (ipsrcchk_rt.ro_rt) { 765 RTFREE(ipsrcchk_rt.ro_rt); 766 ipsrcchk_rt.ro_rt = 0; 767 } 768 #endif 769 } 770 771 /* 772 * Drain off all datagram fragments. 773 */ 774 void 775 frag6_drain(void) 776 { 777 VNET_ITERATOR_DECL(vnet_iter); 778 779 if (IP6Q_TRYLOCK() == 0) 780 return; 781 VNET_LIST_RLOCK(); 782 VNET_FOREACH(vnet_iter) { 783 CURVNET_SET(vnet_iter); 784 INIT_VNET_INET6(vnet_iter); 785 while (V_ip6q.ip6q_next != &V_ip6q) { 786 V_ip6stat.ip6s_fragdropped++; 787 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 788 frag6_freef(V_ip6q.ip6q_next); 789 } 790 CURVNET_RESTORE(); 791 } 792 VNET_LIST_RUNLOCK(); 793 IP6Q_UNLOCK(); 794 } 795