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 V_ip6stat.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 IP6Q_LOCK(); 225 226 /* 227 * Enforce upper bound on number of fragments. 228 * If maxfrag is 0, never accept fragments. 229 * If maxfrag is -1, accept all fragments without limitation. 230 */ 231 if (V_ip6_maxfrags < 0) 232 ; 233 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 234 goto dropfrag; 235 236 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 237 if (ip6f->ip6f_ident == q6->ip6q_ident && 238 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 239 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 240 #ifdef MAC 241 && mac_ip6q_match(m, q6) 242 #endif 243 ) 244 break; 245 246 if (q6 == &V_ip6q) { 247 /* 248 * the first fragment to arrive, create a reassembly queue. 249 */ 250 first_frag = 1; 251 252 /* 253 * Enforce upper bound on number of fragmented packets 254 * for which we attempt reassembly; 255 * If maxfragpackets is 0, never accept fragments. 256 * If maxfragpackets is -1, accept all fragments without 257 * limitation. 258 */ 259 if (V_ip6_maxfragpackets < 0) 260 ; 261 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 262 goto dropfrag; 263 V_frag6_nfragpackets++; 264 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 265 M_NOWAIT); 266 if (q6 == NULL) 267 goto dropfrag; 268 bzero(q6, sizeof(*q6)); 269 #ifdef MAC 270 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 271 free(q6, M_FTABLE); 272 goto dropfrag; 273 } 274 mac_ip6q_create(m, q6); 275 #endif 276 frag6_insque(q6, &V_ip6q); 277 278 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 279 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 280 #ifdef notyet 281 q6->ip6q_nxtp = (u_char *)nxtp; 282 #endif 283 q6->ip6q_ident = ip6f->ip6f_ident; 284 q6->ip6q_ttl = IPV6_FRAGTTL; 285 q6->ip6q_src = ip6->ip6_src; 286 q6->ip6q_dst = ip6->ip6_dst; 287 q6->ip6q_ecn = 288 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 289 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 290 291 q6->ip6q_nfrag = 0; 292 } 293 294 /* 295 * If it's the 1st fragment, record the length of the 296 * unfragmentable part and the next header of the fragment header. 297 */ 298 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 299 if (fragoff == 0) { 300 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 301 sizeof(struct ip6_frag); 302 q6->ip6q_nxt = ip6f->ip6f_nxt; 303 } 304 305 /* 306 * Check that the reassembled packet would not exceed 65535 bytes 307 * in size. 308 * If it would exceed, discard the fragment and return an ICMP error. 309 */ 310 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 311 if (q6->ip6q_unfrglen >= 0) { 312 /* The 1st fragment has already arrived. */ 313 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 314 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 315 offset - sizeof(struct ip6_frag) + 316 offsetof(struct ip6_frag, ip6f_offlg)); 317 IP6Q_UNLOCK(); 318 return (IPPROTO_DONE); 319 } 320 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 321 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 322 offset - sizeof(struct ip6_frag) + 323 offsetof(struct ip6_frag, ip6f_offlg)); 324 IP6Q_UNLOCK(); 325 return (IPPROTO_DONE); 326 } 327 /* 328 * If it's the first fragment, do the above check for each 329 * fragment already stored in the reassembly queue. 330 */ 331 if (fragoff == 0) { 332 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 333 af6 = af6dwn) { 334 af6dwn = af6->ip6af_down; 335 336 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 337 IPV6_MAXPACKET) { 338 struct mbuf *merr = IP6_REASS_MBUF(af6); 339 struct ip6_hdr *ip6err; 340 int erroff = af6->ip6af_offset; 341 342 /* dequeue the fragment. */ 343 frag6_deq(af6); 344 free(af6, M_FTABLE); 345 346 /* adjust pointer. */ 347 ip6err = mtod(merr, struct ip6_hdr *); 348 349 /* 350 * Restore source and destination addresses 351 * in the erroneous IPv6 header. 352 */ 353 ip6err->ip6_src = q6->ip6q_src; 354 ip6err->ip6_dst = q6->ip6q_dst; 355 356 icmp6_error(merr, ICMP6_PARAM_PROB, 357 ICMP6_PARAMPROB_HEADER, 358 erroff - sizeof(struct ip6_frag) + 359 offsetof(struct ip6_frag, ip6f_offlg)); 360 } 361 } 362 } 363 364 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 365 M_NOWAIT); 366 if (ip6af == NULL) 367 goto dropfrag; 368 bzero(ip6af, sizeof(*ip6af)); 369 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 370 ip6af->ip6af_off = fragoff; 371 ip6af->ip6af_frglen = frgpartlen; 372 ip6af->ip6af_offset = offset; 373 IP6_REASS_MBUF(ip6af) = m; 374 375 if (first_frag) { 376 af6 = (struct ip6asfrag *)q6; 377 goto insert; 378 } 379 380 /* 381 * Handle ECN by comparing this segment with the first one; 382 * if CE is set, do not lose CE. 383 * drop if CE and not-ECT are mixed for the same packet. 384 */ 385 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 386 ecn0 = q6->ip6q_ecn; 387 if (ecn == IPTOS_ECN_CE) { 388 if (ecn0 == IPTOS_ECN_NOTECT) { 389 free(ip6af, M_FTABLE); 390 goto dropfrag; 391 } 392 if (ecn0 != IPTOS_ECN_CE) 393 q6->ip6q_ecn = IPTOS_ECN_CE; 394 } 395 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 396 free(ip6af, M_FTABLE); 397 goto dropfrag; 398 } 399 400 /* 401 * Find a segment which begins after this one does. 402 */ 403 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 404 af6 = af6->ip6af_down) 405 if (af6->ip6af_off > ip6af->ip6af_off) 406 break; 407 408 #if 0 409 /* 410 * If there is a preceding segment, it may provide some of 411 * our data already. If so, drop the data from the incoming 412 * segment. If it provides all of our data, drop us. 413 */ 414 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 415 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 416 - ip6af->ip6af_off; 417 if (i > 0) { 418 if (i >= ip6af->ip6af_frglen) 419 goto dropfrag; 420 m_adj(IP6_REASS_MBUF(ip6af), i); 421 ip6af->ip6af_off += i; 422 ip6af->ip6af_frglen -= i; 423 } 424 } 425 426 /* 427 * While we overlap succeeding segments trim them or, 428 * if they are completely covered, dequeue them. 429 */ 430 while (af6 != (struct ip6asfrag *)q6 && 431 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 432 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 433 if (i < af6->ip6af_frglen) { 434 af6->ip6af_frglen -= i; 435 af6->ip6af_off += i; 436 m_adj(IP6_REASS_MBUF(af6), i); 437 break; 438 } 439 af6 = af6->ip6af_down; 440 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 441 frag6_deq(af6->ip6af_up); 442 } 443 #else 444 /* 445 * If the incoming framgent overlaps some existing fragments in 446 * the reassembly queue, drop it, since it is dangerous to override 447 * existing fragments from a security point of view. 448 * We don't know which fragment is the bad guy - here we trust 449 * fragment that came in earlier, with no real reason. 450 * 451 * Note: due to changes after disabling this part, mbuf passed to 452 * m_adj() below now does not meet the requirement. 453 */ 454 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 455 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 456 - ip6af->ip6af_off; 457 if (i > 0) { 458 #if 0 /* suppress the noisy log */ 459 log(LOG_ERR, "%d bytes of a fragment from %s " 460 "overlaps the previous fragment\n", 461 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 462 #endif 463 free(ip6af, M_FTABLE); 464 goto dropfrag; 465 } 466 } 467 if (af6 != (struct ip6asfrag *)q6) { 468 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->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 succeeding fragment", 473 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 474 #endif 475 free(ip6af, M_FTABLE); 476 goto dropfrag; 477 } 478 } 479 #endif 480 481 insert: 482 #ifdef MAC 483 if (!first_frag) 484 mac_ip6q_update(m, q6); 485 #endif 486 487 /* 488 * Stick new segment in its place; 489 * check for complete reassembly. 490 * Move to front of packet queue, as we are 491 * the most recently active fragmented packet. 492 */ 493 frag6_enq(ip6af, af6->ip6af_up); 494 V_frag6_nfrags++; 495 q6->ip6q_nfrag++; 496 #if 0 /* xxx */ 497 if (q6 != V_ip6q.ip6q_next) { 498 frag6_remque(q6); 499 frag6_insque(q6, &V_ip6q); 500 } 501 #endif 502 next = 0; 503 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 504 af6 = af6->ip6af_down) { 505 if (af6->ip6af_off != next) { 506 IP6Q_UNLOCK(); 507 return IPPROTO_DONE; 508 } 509 next += af6->ip6af_frglen; 510 } 511 if (af6->ip6af_up->ip6af_mff) { 512 IP6Q_UNLOCK(); 513 return IPPROTO_DONE; 514 } 515 516 /* 517 * Reassembly is complete; concatenate fragments. 518 */ 519 ip6af = q6->ip6q_down; 520 t = m = IP6_REASS_MBUF(ip6af); 521 af6 = ip6af->ip6af_down; 522 frag6_deq(ip6af); 523 while (af6 != (struct ip6asfrag *)q6) { 524 af6dwn = af6->ip6af_down; 525 frag6_deq(af6); 526 while (t->m_next) 527 t = t->m_next; 528 t->m_next = IP6_REASS_MBUF(af6); 529 m_adj(t->m_next, af6->ip6af_offset); 530 free(af6, M_FTABLE); 531 af6 = af6dwn; 532 } 533 534 /* adjust offset to point where the original next header starts */ 535 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 536 free(ip6af, M_FTABLE); 537 ip6 = mtod(m, struct ip6_hdr *); 538 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 539 if (q6->ip6q_ecn == IPTOS_ECN_CE) 540 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 541 nxt = q6->ip6q_nxt; 542 #ifdef notyet 543 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 544 #endif 545 546 /* Delete frag6 header */ 547 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 548 /* This is the only possible case with !PULLDOWN_TEST */ 549 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 550 offset); 551 m->m_data += sizeof(struct ip6_frag); 552 m->m_len -= sizeof(struct ip6_frag); 553 } else { 554 /* this comes with no copy if the boundary is on cluster */ 555 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 556 frag6_remque(q6); 557 V_frag6_nfrags -= q6->ip6q_nfrag; 558 #ifdef MAC 559 mac_ip6q_destroy(q6); 560 #endif 561 free(q6, M_FTABLE); 562 V_frag6_nfragpackets--; 563 goto dropfrag; 564 } 565 m_adj(t, sizeof(struct ip6_frag)); 566 m_cat(m, t); 567 } 568 569 /* 570 * Store NXT to the original. 571 */ 572 { 573 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 574 *prvnxtp = nxt; 575 } 576 577 frag6_remque(q6); 578 V_frag6_nfrags -= q6->ip6q_nfrag; 579 #ifdef MAC 580 mac_ip6q_reassemble(q6, m); 581 mac_ip6q_destroy(q6); 582 #endif 583 free(q6, M_FTABLE); 584 V_frag6_nfragpackets--; 585 586 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 587 int plen = 0; 588 for (t = m; t; t = t->m_next) 589 plen += t->m_len; 590 m->m_pkthdr.len = plen; 591 } 592 593 V_ip6stat.ip6s_reassembled++; 594 in6_ifstat_inc(dstifp, ifs6_reass_ok); 595 596 /* 597 * Tell launch routine the next header 598 */ 599 600 *mp = m; 601 *offp = offset; 602 603 IP6Q_UNLOCK(); 604 return nxt; 605 606 dropfrag: 607 IP6Q_UNLOCK(); 608 in6_ifstat_inc(dstifp, ifs6_reass_fail); 609 V_ip6stat.ip6s_fragdropped++; 610 m_freem(m); 611 return IPPROTO_DONE; 612 } 613 614 /* 615 * Free a fragment reassembly header and all 616 * associated datagrams. 617 */ 618 void 619 frag6_freef(struct ip6q *q6) 620 { 621 struct ip6asfrag *af6, *down6; 622 623 IP6Q_LOCK_ASSERT(); 624 625 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 626 af6 = down6) { 627 struct mbuf *m = IP6_REASS_MBUF(af6); 628 629 down6 = af6->ip6af_down; 630 frag6_deq(af6); 631 632 /* 633 * Return ICMP time exceeded error for the 1st fragment. 634 * Just free other fragments. 635 */ 636 if (af6->ip6af_off == 0) { 637 struct ip6_hdr *ip6; 638 639 /* adjust pointer */ 640 ip6 = mtod(m, struct ip6_hdr *); 641 642 /* restore source and destination addresses */ 643 ip6->ip6_src = q6->ip6q_src; 644 ip6->ip6_dst = q6->ip6q_dst; 645 646 icmp6_error(m, ICMP6_TIME_EXCEEDED, 647 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 648 } else 649 m_freem(m); 650 free(af6, M_FTABLE); 651 } 652 frag6_remque(q6); 653 V_frag6_nfrags -= q6->ip6q_nfrag; 654 #ifdef MAC 655 mac_ip6q_destroy(q6); 656 #endif 657 free(q6, M_FTABLE); 658 V_frag6_nfragpackets--; 659 } 660 661 /* 662 * Put an ip fragment on a reassembly chain. 663 * Like insque, but pointers in middle of structure. 664 */ 665 void 666 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 667 { 668 669 IP6Q_LOCK_ASSERT(); 670 671 af6->ip6af_up = up6; 672 af6->ip6af_down = up6->ip6af_down; 673 up6->ip6af_down->ip6af_up = af6; 674 up6->ip6af_down = af6; 675 } 676 677 /* 678 * To frag6_enq as remque is to insque. 679 */ 680 void 681 frag6_deq(struct ip6asfrag *af6) 682 { 683 684 IP6Q_LOCK_ASSERT(); 685 686 af6->ip6af_up->ip6af_down = af6->ip6af_down; 687 af6->ip6af_down->ip6af_up = af6->ip6af_up; 688 } 689 690 void 691 frag6_insque(struct ip6q *new, struct ip6q *old) 692 { 693 694 IP6Q_LOCK_ASSERT(); 695 696 new->ip6q_prev = old; 697 new->ip6q_next = old->ip6q_next; 698 old->ip6q_next->ip6q_prev= new; 699 old->ip6q_next = new; 700 } 701 702 void 703 frag6_remque(struct ip6q *p6) 704 { 705 706 IP6Q_LOCK_ASSERT(); 707 708 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 709 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 710 } 711 712 /* 713 * IPv6 reassembling timer processing; 714 * if a timer expires on a reassembly 715 * queue, discard it. 716 */ 717 void 718 frag6_slowtimo(void) 719 { 720 VNET_ITERATOR_DECL(vnet_iter); 721 struct ip6q *q6; 722 723 VNET_LIST_RLOCK_NOSLEEP(); 724 IP6Q_LOCK(); 725 VNET_FOREACH(vnet_iter) { 726 CURVNET_SET(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 IP6Q_UNLOCK(); 752 VNET_LIST_RUNLOCK_NOSLEEP(); 753 } 754 755 /* 756 * Drain off all datagram fragments. 757 */ 758 void 759 frag6_drain(void) 760 { 761 VNET_ITERATOR_DECL(vnet_iter); 762 763 VNET_LIST_RLOCK_NOSLEEP(); 764 if (IP6Q_TRYLOCK() == 0) { 765 VNET_LIST_RUNLOCK_NOSLEEP(); 766 return; 767 } 768 VNET_FOREACH(vnet_iter) { 769 CURVNET_SET(vnet_iter); 770 while (V_ip6q.ip6q_next != &V_ip6q) { 771 V_ip6stat.ip6s_fragdropped++; 772 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 773 frag6_freef(V_ip6q.ip6q_next); 774 } 775 CURVNET_RESTORE(); 776 } 777 IP6Q_UNLOCK(); 778 VNET_LIST_RUNLOCK_NOSLEEP(); 779 } 780