frag6.c revision 121346
1/* $FreeBSD: head/sys/netinet6/frag6.c 121346 2003-10-22 15:32:56Z ume $ */ 2/* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ */ 3 4/* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#include "opt_random_ip_id.h" 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 50#include <netinet/in.h> 51#include <netinet/in_var.h> 52#include <netinet/ip6.h> 53#include <netinet6/ip6_var.h> 54#include <netinet/icmp6.h> 55 56#include <net/net_osdep.h> 57 58/* 59 * Define it to get a correct behavior on per-interface statistics. 60 * You will need to perform an extra routing table lookup, per fragment, 61 * to do it. This may, or may not be, a performance hit. 62 */ 63#define IN6_IFSTAT_STRICT 64 65static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 66static void frag6_deq __P((struct ip6asfrag *)); 67static void frag6_insque __P((struct ip6q *, struct ip6q *)); 68static void frag6_remque __P((struct ip6q *)); 69static void frag6_freef __P((struct ip6q *)); 70 71static struct mtx ip6qlock; 72/* 73 * These fields all protected by ip6qlock. 74 */ 75static u_int frag6_nfragpackets; 76static u_int frag6_nfrags; 77static struct ip6q ip6q; /* ip6 reassemble queue */ 78 79#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80#define IP6Q_LOCK() mtx_lock(&ip6qlock) 81#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82#define IP6Q_LOCK_CHECK() mtx_assert(&ip6qlock, MA_OWNED) 83#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84 85static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 86 87/* 88 * Initialise reassembly queue and fragment identifier. 89 */ 90void 91frag6_init() 92{ 93 94 ip6_maxfragpackets = nmbclusters / 4; 95 ip6_maxfrags = nmbclusters / 4; 96 97 IP6Q_LOCK_INIT(); 98 99#ifndef RANDOM_IP_ID 100 ip6_id = arc4random(); 101#endif 102 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 103} 104 105/* 106 * In RFC2460, fragment and reassembly rule do not agree with each other, 107 * in terms of next header field handling in fragment header. 108 * While the sender will use the same value for all of the fragmented packets, 109 * receiver is suggested not to check the consistency. 110 * 111 * fragment rule (p20): 112 * (2) A Fragment header containing: 113 * The Next Header value that identifies the first header of 114 * the Fragmentable Part of the original packet. 115 * -> next header field is same for all fragments 116 * 117 * reassembly rule (p21): 118 * The Next Header field of the last header of the Unfragmentable 119 * Part is obtained from the Next Header field of the first 120 * fragment's Fragment header. 121 * -> should grab it from the first fragment only 122 * 123 * The following note also contradicts with fragment rule - noone is going to 124 * send different fragment with different next header field. 125 * 126 * additional note (p22): 127 * The Next Header values in the Fragment headers of different 128 * fragments of the same original packet may differ. Only the value 129 * from the Offset zero fragment packet is used for reassembly. 130 * -> should grab it from the first fragment only 131 * 132 * There is no explicit reason given in the RFC. Historical reason maybe? 133 */ 134/* 135 * Fragment input 136 */ 137int 138frag6_input(mp, offp, proto) 139 struct mbuf **mp; 140 int *offp, proto; 141{ 142 struct mbuf *m = *mp, *t; 143 struct ip6_hdr *ip6; 144 struct ip6_frag *ip6f; 145 struct ip6q *q6; 146 struct ip6asfrag *af6, *ip6af, *af6dwn; 147 int offset = *offp, nxt, i, next; 148 int first_frag = 0; 149 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 150 struct ifnet *dstifp; 151#ifdef IN6_IFSTAT_STRICT 152 static struct route_in6 ro; 153 struct sockaddr_in6 *dst; 154#endif 155 156 ip6 = mtod(m, struct ip6_hdr *); 157#ifndef PULLDOWN_TEST 158 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 159 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 160#else 161 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 162 if (ip6f == NULL) 163 return (IPPROTO_DONE); 164#endif 165 166 dstifp = NULL; 167#ifdef IN6_IFSTAT_STRICT 168 /* find the destination interface of the packet. */ 169 dst = (struct sockaddr_in6 *)&ro.ro_dst; 170 if (ro.ro_rt 171 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 172 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 173 RTFREE(ro.ro_rt); 174 ro.ro_rt = (struct rtentry *)0; 175 } 176 if (ro.ro_rt == NULL) { 177 bzero(dst, sizeof(*dst)); 178 dst->sin6_family = AF_INET6; 179 dst->sin6_len = sizeof(struct sockaddr_in6); 180 dst->sin6_addr = ip6->ip6_dst; 181 } 182 rtalloc((struct route *)&ro); 183 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 184 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 185#else 186 /* we are violating the spec, this is not the destination interface */ 187 if ((m->m_flags & M_PKTHDR) != 0) 188 dstifp = m->m_pkthdr.rcvif; 189#endif 190 191 /* jumbo payload can't contain a fragment header */ 192 if (ip6->ip6_plen == 0) { 193 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 194 in6_ifstat_inc(dstifp, ifs6_reass_fail); 195 return IPPROTO_DONE; 196 } 197 198 /* 199 * check whether fragment packet's fragment length is 200 * multiple of 8 octets. 201 * sizeof(struct ip6_frag) == 8 202 * sizeof(struct ip6_hdr) = 40 203 */ 204 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 205 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 206 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 207 offsetof(struct ip6_hdr, ip6_plen)); 208 in6_ifstat_inc(dstifp, ifs6_reass_fail); 209 return IPPROTO_DONE; 210 } 211 212 ip6stat.ip6s_fragments++; 213 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 214 215 /* offset now points to data portion */ 216 offset += sizeof(struct ip6_frag); 217 218 IP6Q_LOCK(); 219 220 /* 221 * Enforce upper bound on number of fragments. 222 * If maxfrag is 0, never accept fragments. 223 * If maxfrag is -1, accept all fragments without limitation. 224 */ 225 if (ip6_maxfrags < 0) 226 ; 227 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 228 goto dropfrag; 229 230 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 231 if (ip6f->ip6f_ident == q6->ip6q_ident && 232 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 233 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 234 break; 235 236 if (q6 == &ip6q) { 237 /* 238 * the first fragment to arrive, create a reassembly queue. 239 */ 240 first_frag = 1; 241 242 /* 243 * Enforce upper bound on number of fragmented packets 244 * for which we attempt reassembly; 245 * If maxfragpackets is 0, never accept fragments. 246 * If maxfragpackets is -1, accept all fragments without 247 * limitation. 248 */ 249 if (ip6_maxfragpackets < 0) 250 ; 251 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 252 goto dropfrag; 253 frag6_nfragpackets++; 254 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 255 M_DONTWAIT); 256 if (q6 == NULL) 257 goto dropfrag; 258 bzero(q6, sizeof(*q6)); 259 260 frag6_insque(q6, &ip6q); 261 262 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 263 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 264#ifdef notyet 265 q6->ip6q_nxtp = (u_char *)nxtp; 266#endif 267 q6->ip6q_ident = ip6f->ip6f_ident; 268 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 269 q6->ip6q_ttl = IPV6_FRAGTTL; 270 q6->ip6q_src = ip6->ip6_src; 271 q6->ip6q_dst = ip6->ip6_dst; 272 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 273 274 q6->ip6q_nfrag = 0; 275 } 276 277 /* 278 * If it's the 1st fragment, record the length of the 279 * unfragmentable part and the next header of the fragment header. 280 */ 281 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 282 if (fragoff == 0) { 283 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 284 sizeof(struct ip6_frag); 285 q6->ip6q_nxt = ip6f->ip6f_nxt; 286 } 287 288 /* 289 * Check that the reassembled packet would not exceed 65535 bytes 290 * in size. 291 * If it would exceed, discard the fragment and return an ICMP error. 292 */ 293 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 294 if (q6->ip6q_unfrglen >= 0) { 295 /* The 1st fragment has already arrived. */ 296 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 297 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 298 offset - sizeof(struct ip6_frag) + 299 offsetof(struct ip6_frag, ip6f_offlg)); 300 IP6Q_UNLOCK(); 301 return (IPPROTO_DONE); 302 } 303 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 304 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 305 offset - sizeof(struct ip6_frag) + 306 offsetof(struct ip6_frag, ip6f_offlg)); 307 IP6Q_UNLOCK(); 308 return (IPPROTO_DONE); 309 } 310 /* 311 * If it's the first fragment, do the above check for each 312 * fragment already stored in the reassembly queue. 313 */ 314 if (fragoff == 0) { 315 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 316 af6 = af6dwn) { 317 af6dwn = af6->ip6af_down; 318 319 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 320 IPV6_MAXPACKET) { 321 struct mbuf *merr = IP6_REASS_MBUF(af6); 322 struct ip6_hdr *ip6err; 323 int erroff = af6->ip6af_offset; 324 325 /* dequeue the fragment. */ 326 frag6_deq(af6); 327 free(af6, M_FTABLE); 328 329 /* adjust pointer. */ 330 ip6err = mtod(merr, struct ip6_hdr *); 331 332 /* 333 * Restore source and destination addresses 334 * in the erroneous IPv6 header. 335 */ 336 ip6err->ip6_src = q6->ip6q_src; 337 ip6err->ip6_dst = q6->ip6q_dst; 338 339 icmp6_error(merr, ICMP6_PARAM_PROB, 340 ICMP6_PARAMPROB_HEADER, 341 erroff - sizeof(struct ip6_frag) + 342 offsetof(struct ip6_frag, ip6f_offlg)); 343 } 344 } 345 } 346 347 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 348 M_DONTWAIT); 349 if (ip6af == NULL) 350 goto dropfrag; 351 bzero(ip6af, sizeof(*ip6af)); 352 ip6af->ip6af_head = ip6->ip6_flow; 353 ip6af->ip6af_len = ip6->ip6_plen; 354 ip6af->ip6af_nxt = ip6->ip6_nxt; 355 ip6af->ip6af_hlim = ip6->ip6_hlim; 356 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 357 ip6af->ip6af_off = fragoff; 358 ip6af->ip6af_frglen = frgpartlen; 359 ip6af->ip6af_offset = offset; 360 IP6_REASS_MBUF(ip6af) = m; 361 362 if (first_frag) { 363 af6 = (struct ip6asfrag *)q6; 364 goto insert; 365 } 366 367 /* 368 * Find a segment which begins after this one does. 369 */ 370 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 371 af6 = af6->ip6af_down) 372 if (af6->ip6af_off > ip6af->ip6af_off) 373 break; 374 375#if 0 376 /* 377 * If there is a preceding segment, it may provide some of 378 * our data already. If so, drop the data from the incoming 379 * segment. If it provides all of our data, drop us. 380 */ 381 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 382 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 383 - ip6af->ip6af_off; 384 if (i > 0) { 385 if (i >= ip6af->ip6af_frglen) 386 goto dropfrag; 387 m_adj(IP6_REASS_MBUF(ip6af), i); 388 ip6af->ip6af_off += i; 389 ip6af->ip6af_frglen -= i; 390 } 391 } 392 393 /* 394 * While we overlap succeeding segments trim them or, 395 * if they are completely covered, dequeue them. 396 */ 397 while (af6 != (struct ip6asfrag *)q6 && 398 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 399 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 400 if (i < af6->ip6af_frglen) { 401 af6->ip6af_frglen -= i; 402 af6->ip6af_off += i; 403 m_adj(IP6_REASS_MBUF(af6), i); 404 break; 405 } 406 af6 = af6->ip6af_down; 407 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 408 frag6_deq(af6->ip6af_up); 409 } 410#else 411 /* 412 * If the incoming framgent overlaps some existing fragments in 413 * the reassembly queue, drop it, since it is dangerous to override 414 * existing fragments from a security point of view. 415 * We don't know which fragment is the bad guy - here we trust 416 * fragment that came in earlier, with no real reason. 417 */ 418 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 419 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 420 - ip6af->ip6af_off; 421 if (i > 0) { 422#if 0 /* suppress the noisy log */ 423 log(LOG_ERR, "%d bytes of a fragment from %s " 424 "overlaps the previous fragment\n", 425 i, ip6_sprintf(&q6->ip6q_src)); 426#endif 427 free(ip6af, M_FTABLE); 428 goto dropfrag; 429 } 430 } 431 if (af6 != (struct ip6asfrag *)q6) { 432 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 433 if (i > 0) { 434#if 0 /* suppress the noisy log */ 435 log(LOG_ERR, "%d bytes of a fragment from %s " 436 "overlaps the succeeding fragment", 437 i, ip6_sprintf(&q6->ip6q_src)); 438#endif 439 free(ip6af, M_FTABLE); 440 goto dropfrag; 441 } 442 } 443#endif 444 445insert: 446 447 /* 448 * Stick new segment in its place; 449 * check for complete reassembly. 450 * Move to front of packet queue, as we are 451 * the most recently active fragmented packet. 452 */ 453 frag6_enq(ip6af, af6->ip6af_up); 454 frag6_nfrags++; 455 q6->ip6q_nfrag++; 456#if 0 /* xxx */ 457 if (q6 != ip6q.ip6q_next) { 458 frag6_remque(q6); 459 frag6_insque(q6, &ip6q); 460 } 461#endif 462 next = 0; 463 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 464 af6 = af6->ip6af_down) { 465 if (af6->ip6af_off != next) { 466 IP6Q_UNLOCK(); 467 return IPPROTO_DONE; 468 } 469 next += af6->ip6af_frglen; 470 } 471 if (af6->ip6af_up->ip6af_mff) { 472 IP6Q_UNLOCK(); 473 return IPPROTO_DONE; 474 } 475 476 /* 477 * Reassembly is complete; concatenate fragments. 478 */ 479 ip6af = q6->ip6q_down; 480 t = m = IP6_REASS_MBUF(ip6af); 481 af6 = ip6af->ip6af_down; 482 frag6_deq(ip6af); 483 while (af6 != (struct ip6asfrag *)q6) { 484 af6dwn = af6->ip6af_down; 485 frag6_deq(af6); 486 while (t->m_next) 487 t = t->m_next; 488 t->m_next = IP6_REASS_MBUF(af6); 489 m_adj(t->m_next, af6->ip6af_offset); 490 free(af6, M_FTABLE); 491 af6 = af6dwn; 492 } 493 494 /* adjust offset to point where the original next header starts */ 495 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 496 free(ip6af, M_FTABLE); 497 ip6 = mtod(m, struct ip6_hdr *); 498 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 499 ip6->ip6_src = q6->ip6q_src; 500 ip6->ip6_dst = q6->ip6q_dst; 501 nxt = q6->ip6q_nxt; 502#ifdef notyet 503 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 504#endif 505 506 /* 507 * Delete frag6 header with as a few cost as possible. 508 */ 509 if (offset < m->m_len) { 510 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 511 offset); 512 m->m_data += sizeof(struct ip6_frag); 513 m->m_len -= sizeof(struct ip6_frag); 514 } else { 515 /* this comes with no copy if the boundary is on cluster */ 516 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 517 frag6_remque(q6); 518 frag6_nfrags -= q6->ip6q_nfrag; 519 free(q6, M_FTABLE); 520 frag6_nfragpackets--; 521 goto dropfrag; 522 } 523 m_adj(t, sizeof(struct ip6_frag)); 524 m_cat(m, t); 525 } 526 527 /* 528 * Store NXT to the original. 529 */ 530 { 531 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 532 *prvnxtp = nxt; 533 } 534 535 frag6_remque(q6); 536 frag6_nfrags -= q6->ip6q_nfrag; 537 free(q6, M_FTABLE); 538 frag6_nfragpackets--; 539 540 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 541 int plen = 0; 542 for (t = m; t; t = t->m_next) 543 plen += t->m_len; 544 m->m_pkthdr.len = plen; 545 } 546 547 ip6stat.ip6s_reassembled++; 548 in6_ifstat_inc(dstifp, ifs6_reass_ok); 549 550 /* 551 * Tell launch routine the next header 552 */ 553 554 *mp = m; 555 *offp = offset; 556 557 IP6Q_UNLOCK(); 558 return nxt; 559 560 dropfrag: 561 IP6Q_UNLOCK(); 562 in6_ifstat_inc(dstifp, ifs6_reass_fail); 563 ip6stat.ip6s_fragdropped++; 564 m_freem(m); 565 return IPPROTO_DONE; 566} 567 568/* 569 * Free a fragment reassembly header and all 570 * associated datagrams. 571 */ 572void 573frag6_freef(q6) 574 struct ip6q *q6; 575{ 576 struct ip6asfrag *af6, *down6; 577 578 IP6Q_LOCK_CHECK(); 579 580 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 581 af6 = down6) { 582 struct mbuf *m = IP6_REASS_MBUF(af6); 583 584 down6 = af6->ip6af_down; 585 frag6_deq(af6); 586 587 /* 588 * Return ICMP time exceeded error for the 1st fragment. 589 * Just free other fragments. 590 */ 591 if (af6->ip6af_off == 0) { 592 struct ip6_hdr *ip6; 593 594 /* adjust pointer */ 595 ip6 = mtod(m, struct ip6_hdr *); 596 597 /* restore source and destination addresses */ 598 ip6->ip6_src = q6->ip6q_src; 599 ip6->ip6_dst = q6->ip6q_dst; 600 601 icmp6_error(m, ICMP6_TIME_EXCEEDED, 602 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 603 } else 604 m_freem(m); 605 free(af6, M_FTABLE); 606 } 607 frag6_remque(q6); 608 frag6_nfrags -= q6->ip6q_nfrag; 609 free(q6, M_FTABLE); 610 frag6_nfragpackets--; 611} 612 613/* 614 * Put an ip fragment on a reassembly chain. 615 * Like insque, but pointers in middle of structure. 616 */ 617void 618frag6_enq(af6, up6) 619 struct ip6asfrag *af6, *up6; 620{ 621 622 IP6Q_LOCK_CHECK(); 623 624 af6->ip6af_up = up6; 625 af6->ip6af_down = up6->ip6af_down; 626 up6->ip6af_down->ip6af_up = af6; 627 up6->ip6af_down = af6; 628} 629 630/* 631 * To frag6_enq as remque is to insque. 632 */ 633void 634frag6_deq(af6) 635 struct ip6asfrag *af6; 636{ 637 638 IP6Q_LOCK_CHECK(); 639 640 af6->ip6af_up->ip6af_down = af6->ip6af_down; 641 af6->ip6af_down->ip6af_up = af6->ip6af_up; 642} 643 644void 645frag6_insque(new, old) 646 struct ip6q *new, *old; 647{ 648 649 IP6Q_LOCK_CHECK(); 650 651 new->ip6q_prev = old; 652 new->ip6q_next = old->ip6q_next; 653 old->ip6q_next->ip6q_prev= new; 654 old->ip6q_next = new; 655} 656 657void 658frag6_remque(p6) 659 struct ip6q *p6; 660{ 661 662 IP6Q_LOCK_CHECK(); 663 664 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 665 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 666} 667 668/* 669 * IPv6 reassembling timer processing; 670 * if a timer expires on a reassembly 671 * queue, discard it. 672 */ 673void 674frag6_slowtimo() 675{ 676 struct ip6q *q6; 677 int s = splnet(); 678 679 IP6Q_LOCK(); 680 q6 = ip6q.ip6q_next; 681 if (q6) 682 while (q6 != &ip6q) { 683 --q6->ip6q_ttl; 684 q6 = q6->ip6q_next; 685 if (q6->ip6q_prev->ip6q_ttl == 0) { 686 ip6stat.ip6s_fragtimeout++; 687 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 688 frag6_freef(q6->ip6q_prev); 689 } 690 } 691 /* 692 * If we are over the maximum number of fragments 693 * (due to the limit being lowered), drain off 694 * enough to get down to the new limit. 695 */ 696 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 697 ip6q.ip6q_prev) { 698 ip6stat.ip6s_fragoverflow++; 699 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 700 frag6_freef(ip6q.ip6q_prev); 701 } 702 IP6Q_UNLOCK(); 703 704#if 0 705 /* 706 * Routing changes might produce a better route than we last used; 707 * make sure we notice eventually, even if forwarding only for one 708 * destination and the cache is never replaced. 709 */ 710 if (ip6_forward_rt.ro_rt) { 711 RTFREE(ip6_forward_rt.ro_rt); 712 ip6_forward_rt.ro_rt = 0; 713 } 714 if (ipsrcchk_rt.ro_rt) { 715 RTFREE(ipsrcchk_rt.ro_rt); 716 ipsrcchk_rt.ro_rt = 0; 717 } 718#endif 719 720 splx(s); 721} 722 723/* 724 * Drain off all datagram fragments. 725 */ 726void 727frag6_drain() 728{ 729 730 if (IP6Q_TRYLOCK() == 0) 731 return; 732 while (ip6q.ip6q_next != &ip6q) { 733 ip6stat.ip6s_fragdropped++; 734 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 735 frag6_freef(ip6q.ip6q_next); 736 } 737 IP6Q_UNLOCK(); 738} 739