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 static u_int frag6_nfragpackets; 81 static u_int frag6_nfrags; 82 static struct ip6q ip6q; /* ip6 reassemble queue */ 83 84 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 85 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 86 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 87 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 88 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 89 90 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 91 92 /* 93 * Initialise reassembly queue and fragment identifier. 94 */ 95 static void 96 frag6_change(void *tag) 97 { 98 INIT_VNET_INET6(curvnet); 99 100 V_ip6_maxfragpackets = nmbclusters / 4; 101 V_ip6_maxfrags = nmbclusters / 4; 102 } 103 104 void 105 frag6_init(void) 106 { 107 INIT_VNET_INET6(curvnet); 108 109 V_ip6_maxfragpackets = nmbclusters / 4; 110 V_ip6_maxfrags = nmbclusters / 4; 111 EVENTHANDLER_REGISTER(nmbclusters_change, 112 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 113 114 IP6Q_LOCK_INIT(); 115 116 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 117 } 118 119 /* 120 * In RFC2460, fragment and reassembly rule do not agree with each other, 121 * in terms of next header field handling in fragment header. 122 * While the sender will use the same value for all of the fragmented packets, 123 * receiver is suggested not to check the consistency. 124 * 125 * fragment rule (p20): 126 * (2) A Fragment header containing: 127 * The Next Header value that identifies the first header of 128 * the Fragmentable Part of the original packet. 129 * -> next header field is same for all fragments 130 * 131 * reassembly rule (p21): 132 * The Next Header field of the last header of the Unfragmentable 133 * Part is obtained from the Next Header field of the first 134 * fragment's Fragment header. 135 * -> should grab it from the first fragment only 136 * 137 * The following note also contradicts with fragment rule - noone is going to 138 * send different fragment with different next header field. 139 * 140 * additional note (p22): 141 * The Next Header values in the Fragment headers of different 142 * fragments of the same original packet may differ. Only the value 143 * from the Offset zero fragment packet is used for reassembly. 144 * -> should grab it from the first fragment only 145 * 146 * There is no explicit reason given in the RFC. Historical reason maybe? 147 */ 148 /* 149 * Fragment input 150 */ 151 int 152 frag6_input(struct mbuf **mp, int *offp, int proto) 153 { 154 INIT_VNET_INET6(curvnet); 155 struct mbuf *m = *mp, *t; 156 struct ip6_hdr *ip6; 157 struct ip6_frag *ip6f; 158 struct ip6q *q6; 159 struct ip6asfrag *af6, *ip6af, *af6dwn; 160 #ifdef IN6_IFSTAT_STRICT 161 struct in6_ifaddr *ia; 162 #endif 163 int offset = *offp, nxt, i, next; 164 int first_frag = 0; 165 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 166 struct ifnet *dstifp; 167 u_int8_t ecn, ecn0; 168 #if 0 169 char ip6buf[INET6_ADDRSTRLEN]; 170 #endif 171 172 ip6 = mtod(m, struct ip6_hdr *); 173 #ifndef PULLDOWN_TEST 174 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 175 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 176 #else 177 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 178 if (ip6f == NULL) 179 return (IPPROTO_DONE); 180 #endif 181 182 dstifp = NULL; 183 #ifdef IN6_IFSTAT_STRICT 184 /* find the destination interface of the packet. */ 185 if ((ia = ip6_getdstifaddr(m)) != NULL) 186 dstifp = ia->ia_ifp; 187 #else 188 /* we are violating the spec, this is not the destination interface */ 189 if ((m->m_flags & M_PKTHDR) != 0) 190 dstifp = m->m_pkthdr.rcvif; 191 #endif 192 193 /* jumbo payload can't contain a fragment header */ 194 if (ip6->ip6_plen == 0) { 195 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 196 in6_ifstat_inc(dstifp, ifs6_reass_fail); 197 return IPPROTO_DONE; 198 } 199 200 /* 201 * check whether fragment packet's fragment length is 202 * multiple of 8 octets. 203 * sizeof(struct ip6_frag) == 8 204 * sizeof(struct ip6_hdr) = 40 205 */ 206 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 207 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 208 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 209 offsetof(struct ip6_hdr, ip6_plen)); 210 in6_ifstat_inc(dstifp, ifs6_reass_fail); 211 return IPPROTO_DONE; 212 } 213 214 V_ip6stat.ip6s_fragments++; 215 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 216 217 /* offset now points to data portion */ 218 offset += sizeof(struct ip6_frag); 219 220 IP6Q_LOCK(); 221 222 /* 223 * Enforce upper bound on number of fragments. 224 * If maxfrag is 0, never accept fragments. 225 * If maxfrag is -1, accept all fragments without limitation. 226 */ 227 if (V_ip6_maxfrags < 0) 228 ; 229 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 230 goto dropfrag; 231 232 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 233 if (ip6f->ip6f_ident == q6->ip6q_ident && 234 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 235 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 236 #ifdef MAC 237 && mac_ip6q_match(m, q6) 238 #endif 239 ) 240 break; 241 242 if (q6 == &V_ip6q) { 243 /* 244 * the first fragment to arrive, create a reassembly queue. 245 */ 246 first_frag = 1; 247 248 /* 249 * Enforce upper bound on number of fragmented packets 250 * for which we attempt reassembly; 251 * If maxfragpackets is 0, never accept fragments. 252 * If maxfragpackets is -1, accept all fragments without 253 * limitation. 254 */ 255 if (V_ip6_maxfragpackets < 0) 256 ; 257 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 258 goto dropfrag; 259 V_frag6_nfragpackets++; 260 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 261 M_NOWAIT); 262 if (q6 == NULL) 263 goto dropfrag; 264 bzero(q6, sizeof(*q6)); 265 #ifdef MAC 266 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 267 free(q6, M_FTABLE); 268 goto dropfrag; 269 } 270 mac_ip6q_create(m, q6); 271 #endif 272 frag6_insque(q6, &V_ip6q); 273 274 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 275 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 276 #ifdef notyet 277 q6->ip6q_nxtp = (u_char *)nxtp; 278 #endif 279 q6->ip6q_ident = ip6f->ip6f_ident; 280 q6->ip6q_ttl = IPV6_FRAGTTL; 281 q6->ip6q_src = ip6->ip6_src; 282 q6->ip6q_dst = ip6->ip6_dst; 283 q6->ip6q_ecn = 284 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 285 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 286 287 q6->ip6q_nfrag = 0; 288 } 289 290 /* 291 * If it's the 1st fragment, record the length of the 292 * unfragmentable part and the next header of the fragment header. 293 */ 294 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 295 if (fragoff == 0) { 296 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 297 sizeof(struct ip6_frag); 298 q6->ip6q_nxt = ip6f->ip6f_nxt; 299 } 300 301 /* 302 * Check that the reassembled packet would not exceed 65535 bytes 303 * in size. 304 * If it would exceed, discard the fragment and return an ICMP error. 305 */ 306 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 307 if (q6->ip6q_unfrglen >= 0) { 308 /* The 1st fragment has already arrived. */ 309 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 310 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 311 offset - sizeof(struct ip6_frag) + 312 offsetof(struct ip6_frag, ip6f_offlg)); 313 IP6Q_UNLOCK(); 314 return (IPPROTO_DONE); 315 } 316 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 317 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 318 offset - sizeof(struct ip6_frag) + 319 offsetof(struct ip6_frag, ip6f_offlg)); 320 IP6Q_UNLOCK(); 321 return (IPPROTO_DONE); 322 } 323 /* 324 * If it's the first fragment, do the above check for each 325 * fragment already stored in the reassembly queue. 326 */ 327 if (fragoff == 0) { 328 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 329 af6 = af6dwn) { 330 af6dwn = af6->ip6af_down; 331 332 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 333 IPV6_MAXPACKET) { 334 struct mbuf *merr = IP6_REASS_MBUF(af6); 335 struct ip6_hdr *ip6err; 336 int erroff = af6->ip6af_offset; 337 338 /* dequeue the fragment. */ 339 frag6_deq(af6); 340 free(af6, M_FTABLE); 341 342 /* adjust pointer. */ 343 ip6err = mtod(merr, struct ip6_hdr *); 344 345 /* 346 * Restore source and destination addresses 347 * in the erroneous IPv6 header. 348 */ 349 ip6err->ip6_src = q6->ip6q_src; 350 ip6err->ip6_dst = q6->ip6q_dst; 351 352 icmp6_error(merr, ICMP6_PARAM_PROB, 353 ICMP6_PARAMPROB_HEADER, 354 erroff - sizeof(struct ip6_frag) + 355 offsetof(struct ip6_frag, ip6f_offlg)); 356 } 357 } 358 } 359 360 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 361 M_NOWAIT); 362 if (ip6af == NULL) 363 goto dropfrag; 364 bzero(ip6af, sizeof(*ip6af)); 365 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 366 ip6af->ip6af_off = fragoff; 367 ip6af->ip6af_frglen = frgpartlen; 368 ip6af->ip6af_offset = offset; 369 IP6_REASS_MBUF(ip6af) = m; 370 371 if (first_frag) { 372 af6 = (struct ip6asfrag *)q6; 373 goto insert; 374 } 375 376 /* 377 * Handle ECN by comparing this segment with the first one; 378 * if CE is set, do not lose CE. 379 * drop if CE and not-ECT are mixed for the same packet. 380 */ 381 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 382 ecn0 = q6->ip6q_ecn; 383 if (ecn == IPTOS_ECN_CE) { 384 if (ecn0 == IPTOS_ECN_NOTECT) { 385 free(ip6af, M_FTABLE); 386 goto dropfrag; 387 } 388 if (ecn0 != IPTOS_ECN_CE) 389 q6->ip6q_ecn = IPTOS_ECN_CE; 390 } 391 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 392 free(ip6af, M_FTABLE); 393 goto dropfrag; 394 } 395 396 /* 397 * Find a segment which begins after this one does. 398 */ 399 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 400 af6 = af6->ip6af_down) 401 if (af6->ip6af_off > ip6af->ip6af_off) 402 break; 403 404 #if 0 405 /* 406 * If there is a preceding segment, it may provide some of 407 * our data already. If so, drop the data from the incoming 408 * segment. If it provides all of our data, drop us. 409 */ 410 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 411 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 412 - ip6af->ip6af_off; 413 if (i > 0) { 414 if (i >= ip6af->ip6af_frglen) 415 goto dropfrag; 416 m_adj(IP6_REASS_MBUF(ip6af), i); 417 ip6af->ip6af_off += i; 418 ip6af->ip6af_frglen -= i; 419 } 420 } 421 422 /* 423 * While we overlap succeeding segments trim them or, 424 * if they are completely covered, dequeue them. 425 */ 426 while (af6 != (struct ip6asfrag *)q6 && 427 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 428 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 429 if (i < af6->ip6af_frglen) { 430 af6->ip6af_frglen -= i; 431 af6->ip6af_off += i; 432 m_adj(IP6_REASS_MBUF(af6), i); 433 break; 434 } 435 af6 = af6->ip6af_down; 436 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 437 frag6_deq(af6->ip6af_up); 438 } 439 #else 440 /* 441 * If the incoming framgent overlaps some existing fragments in 442 * the reassembly queue, drop it, since it is dangerous to override 443 * existing fragments from a security point of view. 444 * We don't know which fragment is the bad guy - here we trust 445 * fragment that came in earlier, with no real reason. 446 * 447 * Note: due to changes after disabling this part, mbuf passed to 448 * m_adj() below now does not meet the requirement. 449 */ 450 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 451 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 452 - ip6af->ip6af_off; 453 if (i > 0) { 454 #if 0 /* suppress the noisy log */ 455 log(LOG_ERR, "%d bytes of a fragment from %s " 456 "overlaps the previous fragment\n", 457 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 458 #endif 459 free(ip6af, M_FTABLE); 460 goto dropfrag; 461 } 462 } 463 if (af6 != (struct ip6asfrag *)q6) { 464 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 465 if (i > 0) { 466 #if 0 /* suppress the noisy log */ 467 log(LOG_ERR, "%d bytes of a fragment from %s " 468 "overlaps the succeeding fragment", 469 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 470 #endif 471 free(ip6af, M_FTABLE); 472 goto dropfrag; 473 } 474 } 475 #endif 476 477 insert: 478 #ifdef MAC 479 if (!first_frag) 480 mac_ip6q_update(m, q6); 481 #endif 482 483 /* 484 * Stick new segment in its place; 485 * check for complete reassembly. 486 * Move to front of packet queue, as we are 487 * the most recently active fragmented packet. 488 */ 489 frag6_enq(ip6af, af6->ip6af_up); 490 V_frag6_nfrags++; 491 q6->ip6q_nfrag++; 492 #if 0 /* xxx */ 493 if (q6 != V_ip6q.ip6q_next) { 494 frag6_remque(q6); 495 frag6_insque(q6, &V_ip6q); 496 } 497 #endif 498 next = 0; 499 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 500 af6 = af6->ip6af_down) { 501 if (af6->ip6af_off != next) { 502 IP6Q_UNLOCK(); 503 return IPPROTO_DONE; 504 } 505 next += af6->ip6af_frglen; 506 } 507 if (af6->ip6af_up->ip6af_mff) { 508 IP6Q_UNLOCK(); 509 return IPPROTO_DONE; 510 } 511 512 /* 513 * Reassembly is complete; concatenate fragments. 514 */ 515 ip6af = q6->ip6q_down; 516 t = m = IP6_REASS_MBUF(ip6af); 517 af6 = ip6af->ip6af_down; 518 frag6_deq(ip6af); 519 while (af6 != (struct ip6asfrag *)q6) { 520 af6dwn = af6->ip6af_down; 521 frag6_deq(af6); 522 while (t->m_next) 523 t = t->m_next; 524 t->m_next = IP6_REASS_MBUF(af6); 525 m_adj(t->m_next, af6->ip6af_offset); 526 free(af6, M_FTABLE); 527 af6 = af6dwn; 528 } 529 530 /* adjust offset to point where the original next header starts */ 531 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 532 free(ip6af, M_FTABLE); 533 ip6 = mtod(m, struct ip6_hdr *); 534 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 535 if (q6->ip6q_ecn == IPTOS_ECN_CE) 536 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 537 nxt = q6->ip6q_nxt; 538 #ifdef notyet 539 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 540 #endif 541 542 /* Delete frag6 header */ 543 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 544 /* This is the only possible case with !PULLDOWN_TEST */ 545 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 546 offset); 547 m->m_data += sizeof(struct ip6_frag); 548 m->m_len -= sizeof(struct ip6_frag); 549 } else { 550 /* this comes with no copy if the boundary is on cluster */ 551 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 552 frag6_remque(q6); 553 V_frag6_nfrags -= q6->ip6q_nfrag; 554 #ifdef MAC 555 mac_ip6q_destroy(q6); 556 #endif 557 free(q6, M_FTABLE); 558 V_frag6_nfragpackets--; 559 goto dropfrag; 560 } 561 m_adj(t, sizeof(struct ip6_frag)); 562 m_cat(m, t); 563 } 564 565 /* 566 * Store NXT to the original. 567 */ 568 { 569 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 570 *prvnxtp = nxt; 571 } 572 573 frag6_remque(q6); 574 V_frag6_nfrags -= q6->ip6q_nfrag; 575 #ifdef MAC 576 mac_ip6q_reassemble(q6, m); 577 mac_ip6q_destroy(q6); 578 #endif 579 free(q6, M_FTABLE); 580 V_frag6_nfragpackets--; 581 582 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 583 int plen = 0; 584 for (t = m; t; t = t->m_next) 585 plen += t->m_len; 586 m->m_pkthdr.len = plen; 587 } 588 589 V_ip6stat.ip6s_reassembled++; 590 in6_ifstat_inc(dstifp, ifs6_reass_ok); 591 592 /* 593 * Tell launch routine the next header 594 */ 595 596 *mp = m; 597 *offp = offset; 598 599 IP6Q_UNLOCK(); 600 return nxt; 601 602 dropfrag: 603 IP6Q_UNLOCK(); 604 in6_ifstat_inc(dstifp, ifs6_reass_fail); 605 V_ip6stat.ip6s_fragdropped++; 606 m_freem(m); 607 return IPPROTO_DONE; 608 } 609 610 /* 611 * Free a fragment reassembly header and all 612 * associated datagrams. 613 */ 614 void 615 frag6_freef(struct ip6q *q6) 616 { 617 INIT_VNET_INET6(curvnet); 618 struct ip6asfrag *af6, *down6; 619 620 IP6Q_LOCK_ASSERT(); 621 622 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 623 af6 = down6) { 624 struct mbuf *m = IP6_REASS_MBUF(af6); 625 626 down6 = af6->ip6af_down; 627 frag6_deq(af6); 628 629 /* 630 * Return ICMP time exceeded error for the 1st fragment. 631 * Just free other fragments. 632 */ 633 if (af6->ip6af_off == 0) { 634 struct ip6_hdr *ip6; 635 636 /* adjust pointer */ 637 ip6 = mtod(m, struct ip6_hdr *); 638 639 /* restore source and destination addresses */ 640 ip6->ip6_src = q6->ip6q_src; 641 ip6->ip6_dst = q6->ip6q_dst; 642 643 icmp6_error(m, ICMP6_TIME_EXCEEDED, 644 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 645 } else 646 m_freem(m); 647 free(af6, M_FTABLE); 648 } 649 frag6_remque(q6); 650 V_frag6_nfrags -= q6->ip6q_nfrag; 651 #ifdef MAC 652 mac_ip6q_destroy(q6); 653 #endif 654 free(q6, M_FTABLE); 655 V_frag6_nfragpackets--; 656 } 657 658 /* 659 * Put an ip fragment on a reassembly chain. 660 * Like insque, but pointers in middle of structure. 661 */ 662 void 663 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 664 { 665 666 IP6Q_LOCK_ASSERT(); 667 668 af6->ip6af_up = up6; 669 af6->ip6af_down = up6->ip6af_down; 670 up6->ip6af_down->ip6af_up = af6; 671 up6->ip6af_down = af6; 672 } 673 674 /* 675 * To frag6_enq as remque is to insque. 676 */ 677 void 678 frag6_deq(struct ip6asfrag *af6) 679 { 680 681 IP6Q_LOCK_ASSERT(); 682 683 af6->ip6af_up->ip6af_down = af6->ip6af_down; 684 af6->ip6af_down->ip6af_up = af6->ip6af_up; 685 } 686 687 void 688 frag6_insque(struct ip6q *new, struct ip6q *old) 689 { 690 691 IP6Q_LOCK_ASSERT(); 692 693 new->ip6q_prev = old; 694 new->ip6q_next = old->ip6q_next; 695 old->ip6q_next->ip6q_prev= new; 696 old->ip6q_next = new; 697 } 698 699 void 700 frag6_remque(struct ip6q *p6) 701 { 702 703 IP6Q_LOCK_ASSERT(); 704 705 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 706 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 707 } 708 709 /* 710 * IPv6 reassembling timer processing; 711 * if a timer expires on a reassembly 712 * queue, discard it. 713 */ 714 void 715 frag6_slowtimo(void) 716 { 717 VNET_ITERATOR_DECL(vnet_iter); 718 struct ip6q *q6; 719 720 IP6Q_LOCK(); 721 VNET_LIST_RLOCK(); 722 VNET_FOREACH(vnet_iter) { 723 CURVNET_SET(vnet_iter); 724 INIT_VNET_INET6(vnet_iter); 725 q6 = V_ip6q.ip6q_next; 726 if (q6) 727 while (q6 != &V_ip6q) { 728 --q6->ip6q_ttl; 729 q6 = q6->ip6q_next; 730 if (q6->ip6q_prev->ip6q_ttl == 0) { 731 V_ip6stat.ip6s_fragtimeout++; 732 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 733 frag6_freef(q6->ip6q_prev); 734 } 735 } 736 /* 737 * If we are over the maximum number of fragments 738 * (due to the limit being lowered), drain off 739 * enough to get down to the new limit. 740 */ 741 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 742 V_ip6q.ip6q_prev) { 743 V_ip6stat.ip6s_fragoverflow++; 744 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 745 frag6_freef(V_ip6q.ip6q_prev); 746 } 747 CURVNET_RESTORE(); 748 } 749 VNET_LIST_RUNLOCK(); 750 IP6Q_UNLOCK(); 751 752 #if 0 753 /* 754 * Routing changes might produce a better route than we last used; 755 * make sure we notice eventually, even if forwarding only for one 756 * destination and the cache is never replaced. 757 */ 758 if (V_ip6_forward_rt.ro_rt) { 759 RTFREE(V_ip6_forward_rt.ro_rt); 760 V_ip6_forward_rt.ro_rt = 0; 761 } 762 if (ipsrcchk_rt.ro_rt) { 763 RTFREE(ipsrcchk_rt.ro_rt); 764 ipsrcchk_rt.ro_rt = 0; 765 } 766 #endif 767 } 768 769 /* 770 * Drain off all datagram fragments. 771 */ 772 void 773 frag6_drain(void) 774 { 775 VNET_ITERATOR_DECL(vnet_iter); 776 777 if (IP6Q_TRYLOCK() == 0) 778 return; 779 VNET_LIST_RLOCK(); 780 VNET_FOREACH(vnet_iter) { 781 CURVNET_SET(vnet_iter); 782 INIT_VNET_INET6(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 VNET_LIST_RUNLOCK(); 791 IP6Q_UNLOCK(); 792 } 793