frag6.c revision 121630
1/* $FreeBSD: head/sys/netinet6/frag6.c 121630 2003-10-28 16:29:26Z 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_ASSERT() 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#ifdef IN6_IFSTAT_STRICT 148 struct in6_ifaddr *ia; 149#endif 150 int offset = *offp, nxt, i, next; 151 int first_frag = 0; 152 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 153 struct ifnet *dstifp; 154 155 ip6 = mtod(m, struct ip6_hdr *); 156#ifndef PULLDOWN_TEST 157 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 158 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 159#else 160 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 161 if (ip6f == NULL) 162 return (IPPROTO_DONE); 163#endif 164 165 dstifp = NULL; 166#ifdef IN6_IFSTAT_STRICT 167 /* find the destination interface of the packet. */ 168 if ((ia = ip6_getdstifaddr(m)) != NULL) 169 dstifp = ia->ia_ifp; 170#else 171 /* we are violating the spec, this is not the destination interface */ 172 if ((m->m_flags & M_PKTHDR) != 0) 173 dstifp = m->m_pkthdr.rcvif; 174#endif 175 176 /* jumbo payload can't contain a fragment header */ 177 if (ip6->ip6_plen == 0) { 178 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 179 in6_ifstat_inc(dstifp, ifs6_reass_fail); 180 return IPPROTO_DONE; 181 } 182 183 /* 184 * check whether fragment packet's fragment length is 185 * multiple of 8 octets. 186 * sizeof(struct ip6_frag) == 8 187 * sizeof(struct ip6_hdr) = 40 188 */ 189 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 190 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 191 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 192 offsetof(struct ip6_hdr, ip6_plen)); 193 in6_ifstat_inc(dstifp, ifs6_reass_fail); 194 return IPPROTO_DONE; 195 } 196 197 ip6stat.ip6s_fragments++; 198 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 199 200 /* offset now points to data portion */ 201 offset += sizeof(struct ip6_frag); 202 203 IP6Q_LOCK(); 204 205 /* 206 * Enforce upper bound on number of fragments. 207 * If maxfrag is 0, never accept fragments. 208 * If maxfrag is -1, accept all fragments without limitation. 209 */ 210 if (ip6_maxfrags < 0) 211 ; 212 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 213 goto dropfrag; 214 215 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 216 if (ip6f->ip6f_ident == q6->ip6q_ident && 217 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 218 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 219 break; 220 221 if (q6 == &ip6q) { 222 /* 223 * the first fragment to arrive, create a reassembly queue. 224 */ 225 first_frag = 1; 226 227 /* 228 * Enforce upper bound on number of fragmented packets 229 * for which we attempt reassembly; 230 * If maxfragpackets is 0, never accept fragments. 231 * If maxfragpackets is -1, accept all fragments without 232 * limitation. 233 */ 234 if (ip6_maxfragpackets < 0) 235 ; 236 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 237 goto dropfrag; 238 frag6_nfragpackets++; 239 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 240 M_NOWAIT); 241 if (q6 == NULL) 242 goto dropfrag; 243 bzero(q6, sizeof(*q6)); 244 245 frag6_insque(q6, &ip6q); 246 247 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 248 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 249#ifdef notyet 250 q6->ip6q_nxtp = (u_char *)nxtp; 251#endif 252 q6->ip6q_ident = ip6f->ip6f_ident; 253 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 254 q6->ip6q_ttl = IPV6_FRAGTTL; 255 q6->ip6q_src = ip6->ip6_src; 256 q6->ip6q_dst = ip6->ip6_dst; 257 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 258 259 q6->ip6q_nfrag = 0; 260 } 261 262 /* 263 * If it's the 1st fragment, record the length of the 264 * unfragmentable part and the next header of the fragment header. 265 */ 266 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 267 if (fragoff == 0) { 268 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 269 sizeof(struct ip6_frag); 270 q6->ip6q_nxt = ip6f->ip6f_nxt; 271 } 272 273 /* 274 * Check that the reassembled packet would not exceed 65535 bytes 275 * in size. 276 * If it would exceed, discard the fragment and return an ICMP error. 277 */ 278 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 279 if (q6->ip6q_unfrglen >= 0) { 280 /* The 1st fragment has already arrived. */ 281 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 282 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 283 offset - sizeof(struct ip6_frag) + 284 offsetof(struct ip6_frag, ip6f_offlg)); 285 IP6Q_UNLOCK(); 286 return (IPPROTO_DONE); 287 } 288 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 289 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 290 offset - sizeof(struct ip6_frag) + 291 offsetof(struct ip6_frag, ip6f_offlg)); 292 IP6Q_UNLOCK(); 293 return (IPPROTO_DONE); 294 } 295 /* 296 * If it's the first fragment, do the above check for each 297 * fragment already stored in the reassembly queue. 298 */ 299 if (fragoff == 0) { 300 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 301 af6 = af6dwn) { 302 af6dwn = af6->ip6af_down; 303 304 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 305 IPV6_MAXPACKET) { 306 struct mbuf *merr = IP6_REASS_MBUF(af6); 307 struct ip6_hdr *ip6err; 308 int erroff = af6->ip6af_offset; 309 310 /* dequeue the fragment. */ 311 frag6_deq(af6); 312 free(af6, M_FTABLE); 313 314 /* adjust pointer. */ 315 ip6err = mtod(merr, struct ip6_hdr *); 316 317 /* 318 * Restore source and destination addresses 319 * in the erroneous IPv6 header. 320 */ 321 ip6err->ip6_src = q6->ip6q_src; 322 ip6err->ip6_dst = q6->ip6q_dst; 323 324 icmp6_error(merr, ICMP6_PARAM_PROB, 325 ICMP6_PARAMPROB_HEADER, 326 erroff - sizeof(struct ip6_frag) + 327 offsetof(struct ip6_frag, ip6f_offlg)); 328 } 329 } 330 } 331 332 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 333 M_NOWAIT); 334 if (ip6af == NULL) 335 goto dropfrag; 336 bzero(ip6af, sizeof(*ip6af)); 337 ip6af->ip6af_head = ip6->ip6_flow; 338 ip6af->ip6af_len = ip6->ip6_plen; 339 ip6af->ip6af_nxt = ip6->ip6_nxt; 340 ip6af->ip6af_hlim = ip6->ip6_hlim; 341 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 342 ip6af->ip6af_off = fragoff; 343 ip6af->ip6af_frglen = frgpartlen; 344 ip6af->ip6af_offset = offset; 345 IP6_REASS_MBUF(ip6af) = m; 346 347 if (first_frag) { 348 af6 = (struct ip6asfrag *)q6; 349 goto insert; 350 } 351 352 /* 353 * Find a segment which begins after this one does. 354 */ 355 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 356 af6 = af6->ip6af_down) 357 if (af6->ip6af_off > ip6af->ip6af_off) 358 break; 359 360#if 0 361 /* 362 * If there is a preceding segment, it may provide some of 363 * our data already. If so, drop the data from the incoming 364 * segment. If it provides all of our data, drop us. 365 */ 366 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 367 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 368 - ip6af->ip6af_off; 369 if (i > 0) { 370 if (i >= ip6af->ip6af_frglen) 371 goto dropfrag; 372 m_adj(IP6_REASS_MBUF(ip6af), i); 373 ip6af->ip6af_off += i; 374 ip6af->ip6af_frglen -= i; 375 } 376 } 377 378 /* 379 * While we overlap succeeding segments trim them or, 380 * if they are completely covered, dequeue them. 381 */ 382 while (af6 != (struct ip6asfrag *)q6 && 383 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 384 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 385 if (i < af6->ip6af_frglen) { 386 af6->ip6af_frglen -= i; 387 af6->ip6af_off += i; 388 m_adj(IP6_REASS_MBUF(af6), i); 389 break; 390 } 391 af6 = af6->ip6af_down; 392 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 393 frag6_deq(af6->ip6af_up); 394 } 395#else 396 /* 397 * If the incoming framgent overlaps some existing fragments in 398 * the reassembly queue, drop it, since it is dangerous to override 399 * existing fragments from a security point of view. 400 * We don't know which fragment is the bad guy - here we trust 401 * fragment that came in earlier, with no real reason. 402 */ 403 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 404 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 405 - ip6af->ip6af_off; 406 if (i > 0) { 407#if 0 /* suppress the noisy log */ 408 log(LOG_ERR, "%d bytes of a fragment from %s " 409 "overlaps the previous fragment\n", 410 i, ip6_sprintf(&q6->ip6q_src)); 411#endif 412 free(ip6af, M_FTABLE); 413 goto dropfrag; 414 } 415 } 416 if (af6 != (struct ip6asfrag *)q6) { 417 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 418 if (i > 0) { 419#if 0 /* suppress the noisy log */ 420 log(LOG_ERR, "%d bytes of a fragment from %s " 421 "overlaps the succeeding fragment", 422 i, ip6_sprintf(&q6->ip6q_src)); 423#endif 424 free(ip6af, M_FTABLE); 425 goto dropfrag; 426 } 427 } 428#endif 429 430insert: 431 432 /* 433 * Stick new segment in its place; 434 * check for complete reassembly. 435 * Move to front of packet queue, as we are 436 * the most recently active fragmented packet. 437 */ 438 frag6_enq(ip6af, af6->ip6af_up); 439 frag6_nfrags++; 440 q6->ip6q_nfrag++; 441#if 0 /* xxx */ 442 if (q6 != ip6q.ip6q_next) { 443 frag6_remque(q6); 444 frag6_insque(q6, &ip6q); 445 } 446#endif 447 next = 0; 448 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 449 af6 = af6->ip6af_down) { 450 if (af6->ip6af_off != next) { 451 IP6Q_UNLOCK(); 452 return IPPROTO_DONE; 453 } 454 next += af6->ip6af_frglen; 455 } 456 if (af6->ip6af_up->ip6af_mff) { 457 IP6Q_UNLOCK(); 458 return IPPROTO_DONE; 459 } 460 461 /* 462 * Reassembly is complete; concatenate fragments. 463 */ 464 ip6af = q6->ip6q_down; 465 t = m = IP6_REASS_MBUF(ip6af); 466 af6 = ip6af->ip6af_down; 467 frag6_deq(ip6af); 468 while (af6 != (struct ip6asfrag *)q6) { 469 af6dwn = af6->ip6af_down; 470 frag6_deq(af6); 471 while (t->m_next) 472 t = t->m_next; 473 t->m_next = IP6_REASS_MBUF(af6); 474 m_adj(t->m_next, af6->ip6af_offset); 475 free(af6, M_FTABLE); 476 af6 = af6dwn; 477 } 478 479 /* adjust offset to point where the original next header starts */ 480 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 481 free(ip6af, M_FTABLE); 482 ip6 = mtod(m, struct ip6_hdr *); 483 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 484 ip6->ip6_src = q6->ip6q_src; 485 ip6->ip6_dst = q6->ip6q_dst; 486 nxt = q6->ip6q_nxt; 487#ifdef notyet 488 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 489#endif 490 491 /* 492 * Delete frag6 header with as a few cost as possible. 493 */ 494 if (offset < m->m_len) { 495 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 496 offset); 497 m->m_data += sizeof(struct ip6_frag); 498 m->m_len -= sizeof(struct ip6_frag); 499 } else { 500 /* this comes with no copy if the boundary is on cluster */ 501 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 502 frag6_remque(q6); 503 frag6_nfrags -= q6->ip6q_nfrag; 504 free(q6, M_FTABLE); 505 frag6_nfragpackets--; 506 goto dropfrag; 507 } 508 m_adj(t, sizeof(struct ip6_frag)); 509 m_cat(m, t); 510 } 511 512 /* 513 * Store NXT to the original. 514 */ 515 { 516 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 517 *prvnxtp = nxt; 518 } 519 520 frag6_remque(q6); 521 frag6_nfrags -= q6->ip6q_nfrag; 522 free(q6, M_FTABLE); 523 frag6_nfragpackets--; 524 525 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 526 int plen = 0; 527 for (t = m; t; t = t->m_next) 528 plen += t->m_len; 529 m->m_pkthdr.len = plen; 530 } 531 532 ip6stat.ip6s_reassembled++; 533 in6_ifstat_inc(dstifp, ifs6_reass_ok); 534 535 /* 536 * Tell launch routine the next header 537 */ 538 539 *mp = m; 540 *offp = offset; 541 542 IP6Q_UNLOCK(); 543 return nxt; 544 545 dropfrag: 546 IP6Q_UNLOCK(); 547 in6_ifstat_inc(dstifp, ifs6_reass_fail); 548 ip6stat.ip6s_fragdropped++; 549 m_freem(m); 550 return IPPROTO_DONE; 551} 552 553/* 554 * Free a fragment reassembly header and all 555 * associated datagrams. 556 */ 557void 558frag6_freef(q6) 559 struct ip6q *q6; 560{ 561 struct ip6asfrag *af6, *down6; 562 563 IP6Q_LOCK_ASSERT(); 564 565 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 566 af6 = down6) { 567 struct mbuf *m = IP6_REASS_MBUF(af6); 568 569 down6 = af6->ip6af_down; 570 frag6_deq(af6); 571 572 /* 573 * Return ICMP time exceeded error for the 1st fragment. 574 * Just free other fragments. 575 */ 576 if (af6->ip6af_off == 0) { 577 struct ip6_hdr *ip6; 578 579 /* adjust pointer */ 580 ip6 = mtod(m, struct ip6_hdr *); 581 582 /* restore source and destination addresses */ 583 ip6->ip6_src = q6->ip6q_src; 584 ip6->ip6_dst = q6->ip6q_dst; 585 586 icmp6_error(m, ICMP6_TIME_EXCEEDED, 587 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 588 } else 589 m_freem(m); 590 free(af6, M_FTABLE); 591 } 592 frag6_remque(q6); 593 frag6_nfrags -= q6->ip6q_nfrag; 594 free(q6, M_FTABLE); 595 frag6_nfragpackets--; 596} 597 598/* 599 * Put an ip fragment on a reassembly chain. 600 * Like insque, but pointers in middle of structure. 601 */ 602void 603frag6_enq(af6, up6) 604 struct ip6asfrag *af6, *up6; 605{ 606 607 IP6Q_LOCK_ASSERT(); 608 609 af6->ip6af_up = up6; 610 af6->ip6af_down = up6->ip6af_down; 611 up6->ip6af_down->ip6af_up = af6; 612 up6->ip6af_down = af6; 613} 614 615/* 616 * To frag6_enq as remque is to insque. 617 */ 618void 619frag6_deq(af6) 620 struct ip6asfrag *af6; 621{ 622 623 IP6Q_LOCK_ASSERT(); 624 625 af6->ip6af_up->ip6af_down = af6->ip6af_down; 626 af6->ip6af_down->ip6af_up = af6->ip6af_up; 627} 628 629void 630frag6_insque(new, old) 631 struct ip6q *new, *old; 632{ 633 634 IP6Q_LOCK_ASSERT(); 635 636 new->ip6q_prev = old; 637 new->ip6q_next = old->ip6q_next; 638 old->ip6q_next->ip6q_prev= new; 639 old->ip6q_next = new; 640} 641 642void 643frag6_remque(p6) 644 struct ip6q *p6; 645{ 646 647 IP6Q_LOCK_ASSERT(); 648 649 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 650 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 651} 652 653/* 654 * IPv6 reassembling timer processing; 655 * if a timer expires on a reassembly 656 * queue, discard it. 657 */ 658void 659frag6_slowtimo() 660{ 661 struct ip6q *q6; 662 int s = splnet(); 663 664 IP6Q_LOCK(); 665 q6 = ip6q.ip6q_next; 666 if (q6) 667 while (q6 != &ip6q) { 668 --q6->ip6q_ttl; 669 q6 = q6->ip6q_next; 670 if (q6->ip6q_prev->ip6q_ttl == 0) { 671 ip6stat.ip6s_fragtimeout++; 672 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 673 frag6_freef(q6->ip6q_prev); 674 } 675 } 676 /* 677 * If we are over the maximum number of fragments 678 * (due to the limit being lowered), drain off 679 * enough to get down to the new limit. 680 */ 681 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 682 ip6q.ip6q_prev) { 683 ip6stat.ip6s_fragoverflow++; 684 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 685 frag6_freef(ip6q.ip6q_prev); 686 } 687 IP6Q_UNLOCK(); 688 689#if 0 690 /* 691 * Routing changes might produce a better route than we last used; 692 * make sure we notice eventually, even if forwarding only for one 693 * destination and the cache is never replaced. 694 */ 695 if (ip6_forward_rt.ro_rt) { 696 RTFREE(ip6_forward_rt.ro_rt); 697 ip6_forward_rt.ro_rt = 0; 698 } 699 if (ipsrcchk_rt.ro_rt) { 700 RTFREE(ipsrcchk_rt.ro_rt); 701 ipsrcchk_rt.ro_rt = 0; 702 } 703#endif 704 705 splx(s); 706} 707 708/* 709 * Drain off all datagram fragments. 710 */ 711void 712frag6_drain() 713{ 714 715 if (IP6Q_TRYLOCK() == 0) 716 return; 717 while (ip6q.ip6q_next != &ip6q) { 718 ip6stat.ip6s_fragdropped++; 719 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 720 frag6_freef(ip6q.ip6q_next); 721 } 722 IP6Q_UNLOCK(); 723} 724