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 #include <sys/vimage.h> 47 48 #include <net/if.h> 49 #include <net/route.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 /* 60 * Define it to get a correct behavior on per-interface statistics. 61 * You will need to perform an extra routing table lookup, per fragment, 62 * to do it. This may, or may not be, a performance hit. 63 */ 64 #define IN6_IFSTAT_STRICT 65 66 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 67 static void frag6_deq(struct ip6asfrag *); 68 static void frag6_insque(struct ip6q *, struct ip6q *); 69 static void frag6_remque(struct ip6q *); 70 static void frag6_freef(struct ip6q *); 71 72 static struct mtx ip6qlock; 73 /* 74 * These fields all protected by ip6qlock. 75 */ 76 static u_int frag6_nfragpackets; 77 static u_int frag6_nfrags; 78 static struct ip6q ip6q; /* ip6 reassemble queue */ 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 INIT_VNET_INET6(curvnet); 95 96 V_ip6_maxfragpackets = nmbclusters / 4; 97 V_ip6_maxfrags = nmbclusters / 4; 98 } 99 100 void 101 frag6_init(void) 102 { 103 INIT_VNET_INET6(curvnet); 104 105 V_ip6_maxfragpackets = nmbclusters / 4; 106 V_ip6_maxfrags = nmbclusters / 4; 107 EVENTHANDLER_REGISTER(nmbclusters_change, 108 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 109 110 IP6Q_LOCK_INIT(); 111 112 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 113 } 114 115 /* 116 * In RFC2460, fragment and reassembly rule do not agree with each other, 117 * in terms of next header field handling in fragment header. 118 * While the sender will use the same value for all of the fragmented packets, 119 * receiver is suggested not to check the consistency. 120 * 121 * fragment rule (p20): 122 * (2) A Fragment header containing: 123 * The Next Header value that identifies the first header of 124 * the Fragmentable Part of the original packet. 125 * -> next header field is same for all fragments 126 * 127 * reassembly rule (p21): 128 * The Next Header field of the last header of the Unfragmentable 129 * Part is obtained from the Next Header field of the first 130 * fragment's Fragment header. 131 * -> should grab it from the first fragment only 132 * 133 * The following note also contradicts with fragment rule - noone is going to 134 * send different fragment with different next header field. 135 * 136 * additional note (p22): 137 * The Next Header values in the Fragment headers of different 138 * fragments of the same original packet may differ. Only the value 139 * from the Offset zero fragment packet is used for reassembly. 140 * -> should grab it from the first fragment only 141 * 142 * There is no explicit reason given in the RFC. Historical reason maybe? 143 */ 144 /* 145 * Fragment input 146 */ 147 int 148 frag6_input(struct mbuf **mp, int *offp, int proto) 149 { 150 INIT_VNET_INET6(curvnet); 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 #ifdef IN6_IFSTAT_STRICT 157 struct in6_ifaddr *ia; 158 #endif 159 int offset = *offp, nxt, i, next; 160 int first_frag = 0; 161 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 162 struct ifnet *dstifp; 163 u_int8_t ecn, ecn0; 164 #if 0 165 char ip6buf[INET6_ADDRSTRLEN]; 166 #endif 167 168 ip6 = mtod(m, struct ip6_hdr *); 169 #ifndef PULLDOWN_TEST 170 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 171 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 172 #else 173 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 174 if (ip6f == NULL) 175 return (IPPROTO_DONE); 176 #endif 177 178 dstifp = NULL; 179 #ifdef IN6_IFSTAT_STRICT 180 /* find the destination interface of the packet. */ 181 if ((ia = ip6_getdstifaddr(m)) != NULL) 182 dstifp = ia->ia_ifp; 183 #else 184 /* we are violating the spec, this is not the destination interface */ 185 if ((m->m_flags & M_PKTHDR) != 0) 186 dstifp = m->m_pkthdr.rcvif; 187 #endif 188 189 /* jumbo payload can't contain a fragment header */ 190 if (ip6->ip6_plen == 0) { 191 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 192 in6_ifstat_inc(dstifp, ifs6_reass_fail); 193 return IPPROTO_DONE; 194 } 195 196 /* 197 * check whether fragment packet's fragment length is 198 * multiple of 8 octets. 199 * sizeof(struct ip6_frag) == 8 200 * sizeof(struct ip6_hdr) = 40 201 */ 202 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 203 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 204 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 205 offsetof(struct ip6_hdr, ip6_plen)); 206 in6_ifstat_inc(dstifp, ifs6_reass_fail); 207 return IPPROTO_DONE; 208 } 209 210 V_ip6stat.ip6s_fragments++; 211 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 212 213 /* offset now points to data portion */ 214 offset += sizeof(struct ip6_frag); 215 216 IP6Q_LOCK(); 217 218 /* 219 * Enforce upper bound on number of fragments. 220 * If maxfrag is 0, never accept fragments. 221 * If maxfrag is -1, accept all fragments without limitation. 222 */ 223 if (V_ip6_maxfrags < 0) 224 ; 225 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 226 goto dropfrag; 227 228 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 229 if (ip6f->ip6f_ident == q6->ip6q_ident && 230 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 231 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 232 break; 233 234 if (q6 == &V_ip6q) { 235 /* 236 * the first fragment to arrive, create a reassembly queue. 237 */ 238 first_frag = 1; 239 240 /* 241 * Enforce upper bound on number of fragmented packets 242 * for which we attempt reassembly; 243 * If maxfragpackets is 0, never accept fragments. 244 * If maxfragpackets is -1, accept all fragments without 245 * limitation. 246 */ 247 if (V_ip6_maxfragpackets < 0) 248 ; 249 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 250 goto dropfrag; 251 V_frag6_nfragpackets++; 252 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 253 M_NOWAIT); 254 if (q6 == NULL) 255 goto dropfrag; 256 bzero(q6, sizeof(*q6)); 257 258 frag6_insque(q6, &V_ip6q); 259 260 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 261 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 262 #ifdef notyet 263 q6->ip6q_nxtp = (u_char *)nxtp; 264 #endif 265 q6->ip6q_ident = ip6f->ip6f_ident; 266 q6->ip6q_ttl = IPV6_FRAGTTL; 267 q6->ip6q_src = ip6->ip6_src; 268 q6->ip6q_dst = ip6->ip6_dst; 269 q6->ip6q_ecn = 270 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 271 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 272 273 q6->ip6q_nfrag = 0; 274 } 275 276 /* 277 * If it's the 1st fragment, record the length of the 278 * unfragmentable part and the next header of the fragment header. 279 */ 280 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 281 if (fragoff == 0) { 282 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 283 sizeof(struct ip6_frag); 284 q6->ip6q_nxt = ip6f->ip6f_nxt; 285 } 286 287 /* 288 * Check that the reassembled packet would not exceed 65535 bytes 289 * in size. 290 * If it would exceed, discard the fragment and return an ICMP error. 291 */ 292 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 293 if (q6->ip6q_unfrglen >= 0) { 294 /* The 1st fragment has already arrived. */ 295 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 296 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 297 offset - sizeof(struct ip6_frag) + 298 offsetof(struct ip6_frag, ip6f_offlg)); 299 IP6Q_UNLOCK(); 300 return (IPPROTO_DONE); 301 } 302 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 303 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 304 offset - sizeof(struct ip6_frag) + 305 offsetof(struct ip6_frag, ip6f_offlg)); 306 IP6Q_UNLOCK(); 307 return (IPPROTO_DONE); 308 } 309 /* 310 * If it's the first fragment, do the above check for each 311 * fragment already stored in the reassembly queue. 312 */ 313 if (fragoff == 0) { 314 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 315 af6 = af6dwn) { 316 af6dwn = af6->ip6af_down; 317 318 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 319 IPV6_MAXPACKET) { 320 struct mbuf *merr = IP6_REASS_MBUF(af6); 321 struct ip6_hdr *ip6err; 322 int erroff = af6->ip6af_offset; 323 324 /* dequeue the fragment. */ 325 frag6_deq(af6); 326 free(af6, M_FTABLE); 327 328 /* adjust pointer. */ 329 ip6err = mtod(merr, struct ip6_hdr *); 330 331 /* 332 * Restore source and destination addresses 333 * in the erroneous IPv6 header. 334 */ 335 ip6err->ip6_src = q6->ip6q_src; 336 ip6err->ip6_dst = q6->ip6q_dst; 337 338 icmp6_error(merr, ICMP6_PARAM_PROB, 339 ICMP6_PARAMPROB_HEADER, 340 erroff - sizeof(struct ip6_frag) + 341 offsetof(struct ip6_frag, ip6f_offlg)); 342 } 343 } 344 } 345 346 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 347 M_NOWAIT); 348 if (ip6af == NULL) 349 goto dropfrag; 350 bzero(ip6af, sizeof(*ip6af)); 351 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 352 ip6af->ip6af_off = fragoff; 353 ip6af->ip6af_frglen = frgpartlen; 354 ip6af->ip6af_offset = offset; 355 IP6_REASS_MBUF(ip6af) = m; 356 357 if (first_frag) { 358 af6 = (struct ip6asfrag *)q6; 359 goto insert; 360 } 361 362 /* 363 * Handle ECN by comparing this segment with the first one; 364 * if CE is set, do not lose CE. 365 * drop if CE and not-ECT are mixed for the same packet. 366 */ 367 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 368 ecn0 = q6->ip6q_ecn; 369 if (ecn == IPTOS_ECN_CE) { 370 if (ecn0 == IPTOS_ECN_NOTECT) { 371 free(ip6af, M_FTABLE); 372 goto dropfrag; 373 } 374 if (ecn0 != IPTOS_ECN_CE) 375 q6->ip6q_ecn = IPTOS_ECN_CE; 376 } 377 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 378 free(ip6af, M_FTABLE); 379 goto dropfrag; 380 } 381 382 /* 383 * Find a segment which begins after this one does. 384 */ 385 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 386 af6 = af6->ip6af_down) 387 if (af6->ip6af_off > ip6af->ip6af_off) 388 break; 389 390 #if 0 391 /* 392 * If there is a preceding segment, it may provide some of 393 * our data already. If so, drop the data from the incoming 394 * segment. If it provides all of our data, drop us. 395 */ 396 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 397 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 398 - ip6af->ip6af_off; 399 if (i > 0) { 400 if (i >= ip6af->ip6af_frglen) 401 goto dropfrag; 402 m_adj(IP6_REASS_MBUF(ip6af), i); 403 ip6af->ip6af_off += i; 404 ip6af->ip6af_frglen -= i; 405 } 406 } 407 408 /* 409 * While we overlap succeeding segments trim them or, 410 * if they are completely covered, dequeue them. 411 */ 412 while (af6 != (struct ip6asfrag *)q6 && 413 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 414 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 415 if (i < af6->ip6af_frglen) { 416 af6->ip6af_frglen -= i; 417 af6->ip6af_off += i; 418 m_adj(IP6_REASS_MBUF(af6), i); 419 break; 420 } 421 af6 = af6->ip6af_down; 422 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 423 frag6_deq(af6->ip6af_up); 424 } 425 #else 426 /* 427 * If the incoming framgent overlaps some existing fragments in 428 * the reassembly queue, drop it, since it is dangerous to override 429 * existing fragments from a security point of view. 430 * We don't know which fragment is the bad guy - here we trust 431 * fragment that came in earlier, with no real reason. 432 * 433 * Note: due to changes after disabling this part, mbuf passed to 434 * m_adj() below now does not meet the requirement. 435 */ 436 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 437 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 438 - ip6af->ip6af_off; 439 if (i > 0) { 440 #if 0 /* suppress the noisy log */ 441 log(LOG_ERR, "%d bytes of a fragment from %s " 442 "overlaps the previous fragment\n", 443 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 444 #endif 445 free(ip6af, M_FTABLE); 446 goto dropfrag; 447 } 448 } 449 if (af6 != (struct ip6asfrag *)q6) { 450 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 451 if (i > 0) { 452 #if 0 /* suppress the noisy log */ 453 log(LOG_ERR, "%d bytes of a fragment from %s " 454 "overlaps the succeeding fragment", 455 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 456 #endif 457 free(ip6af, M_FTABLE); 458 goto dropfrag; 459 } 460 } 461 #endif 462 463 insert: 464 465 /* 466 * Stick new segment in its place; 467 * check for complete reassembly. 468 * Move to front of packet queue, as we are 469 * the most recently active fragmented packet. 470 */ 471 frag6_enq(ip6af, af6->ip6af_up); 472 V_frag6_nfrags++; 473 q6->ip6q_nfrag++; 474 #if 0 /* xxx */ 475 if (q6 != V_ip6q.ip6q_next) { 476 frag6_remque(q6); 477 frag6_insque(q6, &V_ip6q); 478 } 479 #endif 480 next = 0; 481 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 482 af6 = af6->ip6af_down) { 483 if (af6->ip6af_off != next) { 484 IP6Q_UNLOCK(); 485 return IPPROTO_DONE; 486 } 487 next += af6->ip6af_frglen; 488 } 489 if (af6->ip6af_up->ip6af_mff) { 490 IP6Q_UNLOCK(); 491 return IPPROTO_DONE; 492 } 493 494 /* 495 * Reassembly is complete; concatenate fragments. 496 */ 497 ip6af = q6->ip6q_down; 498 t = m = IP6_REASS_MBUF(ip6af); 499 af6 = ip6af->ip6af_down; 500 frag6_deq(ip6af); 501 while (af6 != (struct ip6asfrag *)q6) { 502 af6dwn = af6->ip6af_down; 503 frag6_deq(af6); 504 while (t->m_next) 505 t = t->m_next; 506 t->m_next = IP6_REASS_MBUF(af6); 507 m_adj(t->m_next, af6->ip6af_offset); 508 free(af6, M_FTABLE); 509 af6 = af6dwn; 510 } 511 512 /* adjust offset to point where the original next header starts */ 513 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 514 free(ip6af, M_FTABLE); 515 ip6 = mtod(m, struct ip6_hdr *); 516 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 517 if (q6->ip6q_ecn == IPTOS_ECN_CE) 518 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 519 nxt = q6->ip6q_nxt; 520 #ifdef notyet 521 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 522 #endif 523 524 /* Delete frag6 header */ 525 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 526 /* This is the only possible case with !PULLDOWN_TEST */ 527 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 528 offset); 529 m->m_data += sizeof(struct ip6_frag); 530 m->m_len -= sizeof(struct ip6_frag); 531 } else { 532 /* this comes with no copy if the boundary is on cluster */ 533 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 534 frag6_remque(q6); 535 V_frag6_nfrags -= q6->ip6q_nfrag; 536 free(q6, M_FTABLE); 537 V_frag6_nfragpackets--; 538 goto dropfrag; 539 } 540 m_adj(t, sizeof(struct ip6_frag)); 541 m_cat(m, t); 542 } 543 544 /* 545 * Store NXT to the original. 546 */ 547 { 548 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 549 *prvnxtp = nxt; 550 } 551 552 frag6_remque(q6); 553 V_frag6_nfrags -= q6->ip6q_nfrag; 554 free(q6, M_FTABLE); 555 V_frag6_nfragpackets--; 556 557 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 558 int plen = 0; 559 for (t = m; t; t = t->m_next) 560 plen += t->m_len; 561 m->m_pkthdr.len = plen; 562 } 563 564 V_ip6stat.ip6s_reassembled++; 565 in6_ifstat_inc(dstifp, ifs6_reass_ok); 566 567 /* 568 * Tell launch routine the next header 569 */ 570 571 *mp = m; 572 *offp = offset; 573 574 IP6Q_UNLOCK(); 575 return nxt; 576 577 dropfrag: 578 IP6Q_UNLOCK(); 579 in6_ifstat_inc(dstifp, ifs6_reass_fail); 580 V_ip6stat.ip6s_fragdropped++; 581 m_freem(m); 582 return IPPROTO_DONE; 583 } 584 585 /* 586 * Free a fragment reassembly header and all 587 * associated datagrams. 588 */ 589 void 590 frag6_freef(struct ip6q *q6) 591 { 592 INIT_VNET_INET6(curvnet); 593 struct ip6asfrag *af6, *down6; 594 595 IP6Q_LOCK_ASSERT(); 596 597 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 598 af6 = down6) { 599 struct mbuf *m = IP6_REASS_MBUF(af6); 600 601 down6 = af6->ip6af_down; 602 frag6_deq(af6); 603 604 /* 605 * Return ICMP time exceeded error for the 1st fragment. 606 * Just free other fragments. 607 */ 608 if (af6->ip6af_off == 0) { 609 struct ip6_hdr *ip6; 610 611 /* adjust pointer */ 612 ip6 = mtod(m, struct ip6_hdr *); 613 614 /* restore source and destination addresses */ 615 ip6->ip6_src = q6->ip6q_src; 616 ip6->ip6_dst = q6->ip6q_dst; 617 618 icmp6_error(m, ICMP6_TIME_EXCEEDED, 619 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 620 } else 621 m_freem(m); 622 free(af6, M_FTABLE); 623 } 624 frag6_remque(q6); 625 V_frag6_nfrags -= q6->ip6q_nfrag; 626 free(q6, M_FTABLE); 627 V_frag6_nfragpackets--; 628 } 629 630 /* 631 * Put an ip fragment on a reassembly chain. 632 * Like insque, but pointers in middle of structure. 633 */ 634 void 635 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 636 { 637 638 IP6Q_LOCK_ASSERT(); 639 640 af6->ip6af_up = up6; 641 af6->ip6af_down = up6->ip6af_down; 642 up6->ip6af_down->ip6af_up = af6; 643 up6->ip6af_down = af6; 644 } 645 646 /* 647 * To frag6_enq as remque is to insque. 648 */ 649 void 650 frag6_deq(struct ip6asfrag *af6) 651 { 652 653 IP6Q_LOCK_ASSERT(); 654 655 af6->ip6af_up->ip6af_down = af6->ip6af_down; 656 af6->ip6af_down->ip6af_up = af6->ip6af_up; 657 } 658 659 void 660 frag6_insque(struct ip6q *new, struct ip6q *old) 661 { 662 663 IP6Q_LOCK_ASSERT(); 664 665 new->ip6q_prev = old; 666 new->ip6q_next = old->ip6q_next; 667 old->ip6q_next->ip6q_prev= new; 668 old->ip6q_next = new; 669 } 670 671 void 672 frag6_remque(struct ip6q *p6) 673 { 674 675 IP6Q_LOCK_ASSERT(); 676 677 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 678 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 679 } 680 681 /* 682 * IPv6 reassembling timer processing; 683 * if a timer expires on a reassembly 684 * queue, discard it. 685 */ 686 void 687 frag6_slowtimo(void) 688 { 689 VNET_ITERATOR_DECL(vnet_iter); 690 struct ip6q *q6; 691 692 IP6Q_LOCK(); 693 VNET_LIST_RLOCK(); 694 VNET_FOREACH(vnet_iter) { 695 CURVNET_SET(vnet_iter); 696 INIT_VNET_INET6(vnet_iter); 697 q6 = V_ip6q.ip6q_next; 698 if (q6) 699 while (q6 != &V_ip6q) { 700 --q6->ip6q_ttl; 701 q6 = q6->ip6q_next; 702 if (q6->ip6q_prev->ip6q_ttl == 0) { 703 V_ip6stat.ip6s_fragtimeout++; 704 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 705 frag6_freef(q6->ip6q_prev); 706 } 707 } 708 /* 709 * If we are over the maximum number of fragments 710 * (due to the limit being lowered), drain off 711 * enough to get down to the new limit. 712 */ 713 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 714 V_ip6q.ip6q_prev) { 715 V_ip6stat.ip6s_fragoverflow++; 716 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 717 frag6_freef(V_ip6q.ip6q_prev); 718 } 719 CURVNET_RESTORE(); 720 } 721 VNET_LIST_RUNLOCK(); 722 IP6Q_UNLOCK(); 723 724 #if 0 725 /* 726 * Routing changes might produce a better route than we last used; 727 * make sure we notice eventually, even if forwarding only for one 728 * destination and the cache is never replaced. 729 */ 730 if (V_ip6_forward_rt.ro_rt) { 731 RTFREE(V_ip6_forward_rt.ro_rt); 732 V_ip6_forward_rt.ro_rt = 0; 733 } 734 if (ipsrcchk_rt.ro_rt) { 735 RTFREE(ipsrcchk_rt.ro_rt); 736 ipsrcchk_rt.ro_rt = 0; 737 } 738 #endif 739 } 740 741 /* 742 * Drain off all datagram fragments. 743 */ 744 void 745 frag6_drain(void) 746 { 747 VNET_ITERATOR_DECL(vnet_iter); 748 749 if (IP6Q_TRYLOCK() == 0) 750 return; 751 VNET_LIST_RLOCK(); 752 VNET_FOREACH(vnet_iter) { 753 CURVNET_SET(vnet_iter); 754 INIT_VNET_INET6(vnet_iter); 755 while (V_ip6q.ip6q_next != &V_ip6q) { 756 V_ip6stat.ip6s_fragdropped++; 757 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 758 frag6_freef(V_ip6q.ip6q_next); 759 } 760 CURVNET_RESTORE(); 761 } 762 VNET_LIST_RUNLOCK(); 763 IP6Q_UNLOCK(); 764 } 765