1 /* $FreeBSD: src/sys/netinet6/frag6.c,v 1.2.2.6 2002/04/28 05:40:26 suz Exp $ */ 2 /* $DragonFly: src/sys/netinet6/frag6.c,v 1.12 2008/01/05 14:02:40 swildner Exp $ */ 3 /* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ */ 4 5 /* 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the project nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/malloc.h> 37 #include <sys/mbuf.h> 38 #include <sys/domain.h> 39 #include <sys/protosw.h> 40 #include <sys/socket.h> 41 #include <sys/errno.h> 42 #include <sys/time.h> 43 #include <sys/kernel.h> 44 #include <sys/syslog.h> 45 #include <sys/thread2.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 65 static void frag6_enq (struct ip6asfrag *, struct ip6asfrag *); 66 static void frag6_deq (struct ip6asfrag *); 67 static void frag6_insque (struct ip6q *, struct ip6q *); 68 static void frag6_remque (struct ip6q *); 69 static void frag6_freef (struct ip6q *); 70 71 /* XXX we eventually need splreass6, or some real semaphore */ 72 int frag6_doing_reass; 73 u_int frag6_nfragpackets; 74 struct ip6q ip6q; /* ip6 reassemble queue */ 75 76 /* FreeBSD tweak */ 77 MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 78 79 /* 80 * Initialise reassembly queue and fragment identifier. 81 */ 82 void 83 frag6_init(void) 84 { 85 struct timeval tv; 86 87 ip6_maxfragpackets = nmbclusters / 4; 88 89 /* 90 * in many cases, random() here does NOT return random number 91 * as initialization during bootstrap time occur in fixed order. 92 */ 93 microtime(&tv); 94 ip6_id = krandom() ^ tv.tv_usec; 95 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 96 } 97 98 /* 99 * In RFC2460, fragment and reassembly rule do not agree with each other, 100 * in terms of next header field handling in fragment header. 101 * While the sender will use the same value for all of the fragmented packets, 102 * receiver is suggested not to check the consistency. 103 * 104 * fragment rule (p20): 105 * (2) A Fragment header containing: 106 * The Next Header value that identifies the first header of 107 * the Fragmentable Part of the original packet. 108 * -> next header field is same for all fragments 109 * 110 * reassembly rule (p21): 111 * The Next Header field of the last header of the Unfragmentable 112 * Part is obtained from the Next Header field of the first 113 * fragment's Fragment header. 114 * -> should grab it from the first fragment only 115 * 116 * The following note also contradicts with fragment rule - noone is going to 117 * send different fragment with different next header field. 118 * 119 * additional note (p22): 120 * The Next Header values in the Fragment headers of different 121 * fragments of the same original packet may differ. Only the value 122 * from the Offset zero fragment packet is used for reassembly. 123 * -> should grab it from the first fragment only 124 * 125 * There is no explicit reason given in the RFC. Historical reason maybe? 126 */ 127 /* 128 * Fragment input 129 */ 130 int 131 frag6_input(struct mbuf **mp, int *offp, int proto) 132 { 133 struct mbuf *m = *mp, *t; 134 struct ip6_hdr *ip6; 135 struct ip6_frag *ip6f; 136 struct ip6q *q6; 137 struct ip6asfrag *af6, *ip6af, *af6dwn; 138 int offset = *offp, nxt, i, next; 139 int first_frag = 0; 140 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 141 struct ifnet *dstifp; 142 #ifdef IN6_IFSTAT_STRICT 143 static struct route_in6 ro; 144 struct sockaddr_in6 *dst; 145 #endif 146 147 ip6 = mtod(m, struct ip6_hdr *); 148 #ifndef PULLDOWN_TEST 149 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 150 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 151 #else 152 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 153 if (ip6f == NULL) 154 return IPPROTO_DONE; 155 #endif 156 157 dstifp = NULL; 158 #ifdef IN6_IFSTAT_STRICT 159 /* find the destination interface of the packet. */ 160 dst = (struct sockaddr_in6 *)&ro.ro_dst; 161 if (ro.ro_rt && 162 (!(ro.ro_rt->rt_flags & RTF_UP) || 163 !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 164 rtfree(ro.ro_rt); 165 ro.ro_rt = NULL; 166 } 167 if (ro.ro_rt == NULL) { 168 bzero(dst, sizeof(*dst)); 169 dst->sin6_family = AF_INET6; 170 dst->sin6_len = sizeof(struct sockaddr_in6); 171 dst->sin6_addr = ip6->ip6_dst; 172 } 173 rtalloc((struct route *)&ro); 174 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 175 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 176 #else 177 /* we are violating the spec, this is not the destination interface */ 178 if (m->m_flags & M_PKTHDR) 179 dstifp = m->m_pkthdr.rcvif; 180 #endif 181 182 /* jumbo payload can't contain a fragment header */ 183 if (ip6->ip6_plen == 0) { 184 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 185 in6_ifstat_inc(dstifp, ifs6_reass_fail); 186 return IPPROTO_DONE; 187 } 188 189 /* 190 * check whether fragment packet's fragment length is 191 * multiple of 8 octets. 192 * sizeof(struct ip6_frag) == 8 193 * sizeof(struct ip6_hdr) = 40 194 */ 195 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 196 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 197 icmp6_error(m, ICMP6_PARAM_PROB, 198 ICMP6_PARAMPROB_HEADER, 199 offsetof(struct ip6_hdr, ip6_plen)); 200 in6_ifstat_inc(dstifp, ifs6_reass_fail); 201 return IPPROTO_DONE; 202 } 203 204 ip6stat.ip6s_fragments++; 205 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 206 207 /* offset now points to data portion */ 208 offset += sizeof(struct ip6_frag); 209 210 frag6_doing_reass = 1; 211 212 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 213 if (ip6f->ip6f_ident == q6->ip6q_ident && 214 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 215 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 216 break; 217 218 if (q6 == &ip6q) { 219 /* 220 * the first fragment to arrive, create a reassembly queue. 221 */ 222 first_frag = 1; 223 224 /* 225 * Enforce upper bound on number of fragmented packets 226 * for which we attempt reassembly; 227 * If maxfrag is 0, never accept fragments. 228 * If maxfrag is -1, accept all fragments without limitation. 229 */ 230 if (ip6_maxfragpackets < 0) 231 ; 232 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 233 goto dropfrag; 234 frag6_nfragpackets++; 235 q6 = (struct ip6q *)kmalloc(sizeof(struct ip6q), M_FTABLE, 236 M_NOWAIT | M_ZERO); 237 if (q6 == NULL) 238 goto dropfrag; 239 240 frag6_insque(q6, &ip6q); 241 242 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 243 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 244 #ifdef notyet 245 q6->ip6q_nxtp = (u_char *)nxtp; 246 #endif 247 q6->ip6q_ident = ip6f->ip6f_ident; 248 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 249 q6->ip6q_ttl = IPV6_FRAGTTL; 250 q6->ip6q_src = ip6->ip6_src; 251 q6->ip6q_dst = ip6->ip6_dst; 252 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 253 } 254 255 /* 256 * If it's the 1st fragment, record the length of the 257 * unfragmentable part and the next header of the fragment header. 258 */ 259 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 260 if (fragoff == 0) { 261 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 262 - sizeof(struct ip6_frag); 263 q6->ip6q_nxt = ip6f->ip6f_nxt; 264 } 265 266 /* 267 * Check that the reassembled packet would not exceed 65535 bytes 268 * in size. 269 * If it would exceed, discard the fragment and return an ICMP error. 270 */ 271 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 272 if (q6->ip6q_unfrglen >= 0) { 273 /* The 1st fragment has already arrived. */ 274 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 275 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 276 offset - sizeof(struct ip6_frag) + 277 offsetof(struct ip6_frag, ip6f_offlg)); 278 frag6_doing_reass = 0; 279 return (IPPROTO_DONE); 280 } 281 } 282 else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 283 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 284 offset - sizeof(struct ip6_frag) + 285 offsetof(struct ip6_frag, ip6f_offlg)); 286 frag6_doing_reass = 0; 287 return (IPPROTO_DONE); 288 } 289 /* 290 * If it's the first fragment, do the above check for each 291 * fragment already stored in the reassembly queue. 292 */ 293 if (fragoff == 0) { 294 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 295 af6 = af6dwn) { 296 af6dwn = af6->ip6af_down; 297 298 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 299 IPV6_MAXPACKET) { 300 struct mbuf *merr = IP6_REASS_MBUF(af6); 301 struct ip6_hdr *ip6err; 302 int erroff = af6->ip6af_offset; 303 304 /* dequeue the fragment. */ 305 frag6_deq(af6); 306 kfree(af6, M_FTABLE); 307 308 /* adjust pointer. */ 309 ip6err = mtod(merr, struct ip6_hdr *); 310 311 /* 312 * Restore source and destination addresses 313 * in the erroneous IPv6 header. 314 */ 315 ip6err->ip6_src = q6->ip6q_src; 316 ip6err->ip6_dst = q6->ip6q_dst; 317 318 icmp6_error(merr, ICMP6_PARAM_PROB, 319 ICMP6_PARAMPROB_HEADER, 320 erroff - sizeof(struct ip6_frag) + 321 offsetof(struct ip6_frag, ip6f_offlg)); 322 } 323 } 324 } 325 326 ip6af = (struct ip6asfrag *)kmalloc(sizeof(struct ip6asfrag), M_FTABLE, 327 M_NOWAIT | M_ZERO); 328 if (ip6af == NULL) 329 goto dropfrag; 330 ip6af->ip6af_head = ip6->ip6_flow; 331 ip6af->ip6af_len = ip6->ip6_plen; 332 ip6af->ip6af_nxt = ip6->ip6_nxt; 333 ip6af->ip6af_hlim = ip6->ip6_hlim; 334 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 335 ip6af->ip6af_off = fragoff; 336 ip6af->ip6af_frglen = frgpartlen; 337 ip6af->ip6af_offset = offset; 338 IP6_REASS_MBUF(ip6af) = m; 339 340 if (first_frag) { 341 af6 = (struct ip6asfrag *)q6; 342 goto insert; 343 } 344 345 /* 346 * Find a segment which begins after this one does. 347 */ 348 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 349 af6 = af6->ip6af_down) 350 if (af6->ip6af_off > ip6af->ip6af_off) 351 break; 352 353 #if 0 354 /* 355 * If there is a preceding segment, it may provide some of 356 * our data already. If so, drop the data from the incoming 357 * segment. If it provides all of our data, drop us. 358 */ 359 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 360 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 361 - ip6af->ip6af_off; 362 if (i > 0) { 363 if (i >= ip6af->ip6af_frglen) 364 goto dropfrag; 365 m_adj(IP6_REASS_MBUF(ip6af), i); 366 ip6af->ip6af_off += i; 367 ip6af->ip6af_frglen -= i; 368 } 369 } 370 371 /* 372 * While we overlap succeeding segments trim them or, 373 * if they are completely covered, dequeue them. 374 */ 375 while (af6 != (struct ip6asfrag *)q6 && 376 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 377 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 378 if (i < af6->ip6af_frglen) { 379 af6->ip6af_frglen -= i; 380 af6->ip6af_off += i; 381 m_adj(IP6_REASS_MBUF(af6), i); 382 break; 383 } 384 af6 = af6->ip6af_down; 385 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 386 frag6_deq(af6->ip6af_up); 387 } 388 #else 389 /* 390 * If the incoming framgent overlaps some existing fragments in 391 * the reassembly queue, drop it, since it is dangerous to override 392 * existing fragments from a security point of view. 393 */ 394 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 395 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 396 - ip6af->ip6af_off; 397 if (i > 0) { 398 #if 0 /* suppress the noisy log */ 399 log(LOG_ERR, "%d bytes of a fragment from %s " 400 "overlaps the previous fragment\n", 401 i, ip6_sprintf(&q6->ip6q_src)); 402 #endif 403 kfree(ip6af, M_FTABLE); 404 goto dropfrag; 405 } 406 } 407 if (af6 != (struct ip6asfrag *)q6) { 408 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 409 if (i > 0) { 410 #if 0 /* suppress the noisy log */ 411 log(LOG_ERR, "%d bytes of a fragment from %s " 412 "overlaps the succeeding fragment", 413 i, ip6_sprintf(&q6->ip6q_src)); 414 #endif 415 kfree(ip6af, M_FTABLE); 416 goto dropfrag; 417 } 418 } 419 #endif 420 421 insert: 422 423 /* 424 * Stick new segment in its place; 425 * check for complete reassembly. 426 * Move to front of packet queue, as we are 427 * the most recently active fragmented packet. 428 */ 429 frag6_enq(ip6af, af6->ip6af_up); 430 #if 0 /* xxx */ 431 if (q6 != ip6q.ip6q_next) { 432 frag6_remque(q6); 433 frag6_insque(q6, &ip6q); 434 } 435 #endif 436 next = 0; 437 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 438 af6 = af6->ip6af_down) { 439 if (af6->ip6af_off != next) { 440 frag6_doing_reass = 0; 441 return IPPROTO_DONE; 442 } 443 next += af6->ip6af_frglen; 444 } 445 if (af6->ip6af_up->ip6af_mff) { 446 frag6_doing_reass = 0; 447 return IPPROTO_DONE; 448 } 449 450 /* 451 * Reassembly is complete; concatenate fragments. 452 */ 453 ip6af = q6->ip6q_down; 454 t = m = IP6_REASS_MBUF(ip6af); 455 af6 = ip6af->ip6af_down; 456 frag6_deq(ip6af); 457 while (af6 != (struct ip6asfrag *)q6) { 458 af6dwn = af6->ip6af_down; 459 frag6_deq(af6); 460 while (t->m_next) 461 t = t->m_next; 462 t->m_next = IP6_REASS_MBUF(af6); 463 m_adj(t->m_next, af6->ip6af_offset); 464 kfree(af6, M_FTABLE); 465 af6 = af6dwn; 466 } 467 468 /* adjust offset to point where the original next header starts */ 469 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 470 kfree(ip6af, M_FTABLE); 471 ip6 = mtod(m, struct ip6_hdr *); 472 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 473 ip6->ip6_src = q6->ip6q_src; 474 ip6->ip6_dst = q6->ip6q_dst; 475 nxt = q6->ip6q_nxt; 476 #ifdef notyet 477 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 478 #endif 479 480 /* 481 * Delete frag6 header with as a few cost as possible. 482 */ 483 if (offset < m->m_len) { 484 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 485 offset); 486 m->m_data += sizeof(struct ip6_frag); 487 m->m_len -= sizeof(struct ip6_frag); 488 } else { 489 /* this comes with no copy if the boundary is on cluster */ 490 if ((t = m_split(m, offset, MB_DONTWAIT)) == NULL) { 491 frag6_remque(q6); 492 kfree(q6, M_FTABLE); 493 frag6_nfragpackets--; 494 goto dropfrag; 495 } 496 m_adj(t, sizeof(struct ip6_frag)); 497 m_cat(m, t); 498 } 499 500 /* 501 * Store NXT to the original. 502 */ 503 { 504 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 505 *prvnxtp = nxt; 506 } 507 508 frag6_remque(q6); 509 kfree(q6, M_FTABLE); 510 frag6_nfragpackets--; 511 512 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 513 int plen = 0; 514 for (t = m; t; t = t->m_next) 515 plen += t->m_len; 516 m->m_pkthdr.len = plen; 517 } 518 519 ip6stat.ip6s_reassembled++; 520 in6_ifstat_inc(dstifp, ifs6_reass_ok); 521 522 /* 523 * Reassembly complete, return the next protocol. 524 * Be sure to clear M_HASH to force the packet 525 * to be re-characterized. 526 */ 527 m->m_flags &= ~M_HASH; 528 529 *mp = m; 530 *offp = offset; 531 532 frag6_doing_reass = 0; 533 return nxt; 534 535 dropfrag: 536 in6_ifstat_inc(dstifp, ifs6_reass_fail); 537 ip6stat.ip6s_fragdropped++; 538 m_freem(m); 539 frag6_doing_reass = 0; 540 return IPPROTO_DONE; 541 } 542 543 /* 544 * Free a fragment reassembly header and all 545 * associated datagrams. 546 */ 547 void 548 frag6_freef(struct ip6q *q6) 549 { 550 struct ip6asfrag *af6, *down6; 551 552 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 553 af6 = down6) { 554 struct mbuf *m = IP6_REASS_MBUF(af6); 555 556 down6 = af6->ip6af_down; 557 frag6_deq(af6); 558 559 /* 560 * Return ICMP time exceeded error for the 1st fragment. 561 * Just free other fragments. 562 */ 563 if (af6->ip6af_off == 0) { 564 struct ip6_hdr *ip6; 565 566 /* adjust pointer */ 567 ip6 = mtod(m, struct ip6_hdr *); 568 569 /* restoure source and destination addresses */ 570 ip6->ip6_src = q6->ip6q_src; 571 ip6->ip6_dst = q6->ip6q_dst; 572 573 icmp6_error(m, ICMP6_TIME_EXCEEDED, 574 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 575 } else 576 m_freem(m); 577 kfree(af6, M_FTABLE); 578 } 579 frag6_remque(q6); 580 kfree(q6, M_FTABLE); 581 frag6_nfragpackets--; 582 } 583 584 /* 585 * Put an ip fragment on a reassembly chain. 586 * Like insque, but pointers in middle of structure. 587 */ 588 void 589 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 590 { 591 af6->ip6af_up = up6; 592 af6->ip6af_down = up6->ip6af_down; 593 up6->ip6af_down->ip6af_up = af6; 594 up6->ip6af_down = af6; 595 } 596 597 /* 598 * To frag6_enq as remque is to insque. 599 */ 600 void 601 frag6_deq(struct ip6asfrag *af6) 602 { 603 af6->ip6af_up->ip6af_down = af6->ip6af_down; 604 af6->ip6af_down->ip6af_up = af6->ip6af_up; 605 } 606 607 void 608 frag6_insque(struct ip6q *new, struct ip6q *old) 609 { 610 new->ip6q_prev = old; 611 new->ip6q_next = old->ip6q_next; 612 old->ip6q_next->ip6q_prev= new; 613 old->ip6q_next = new; 614 } 615 616 void 617 frag6_remque(struct ip6q *p6) 618 { 619 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 620 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 621 } 622 623 /* 624 * IPv6 reassembling timer processing; 625 * if a timer expires on a reassembly 626 * queue, discard it. 627 */ 628 void 629 frag6_slowtimo(void) 630 { 631 struct ip6q *q6; 632 633 crit_enter(); 634 frag6_doing_reass = 1; 635 q6 = ip6q.ip6q_next; 636 if (q6) 637 while (q6 != &ip6q) { 638 --q6->ip6q_ttl; 639 q6 = q6->ip6q_next; 640 if (q6->ip6q_prev->ip6q_ttl == 0) { 641 ip6stat.ip6s_fragtimeout++; 642 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 643 frag6_freef(q6->ip6q_prev); 644 } 645 } 646 /* 647 * If we are over the maximum number of fragments 648 * (due to the limit being lowered), drain off 649 * enough to get down to the new limit. 650 */ 651 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 652 ip6q.ip6q_prev) { 653 ip6stat.ip6s_fragoverflow++; 654 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 655 frag6_freef(ip6q.ip6q_prev); 656 } 657 frag6_doing_reass = 0; 658 659 #if 0 660 /* 661 * Routing changes might produce a better route than we last used; 662 * make sure we notice eventually, even if forwarding only for one 663 * destination and the cache is never replaced. 664 */ 665 if (ip6_forward_rt.ro_rt) { 666 RTFREE(ip6_forward_rt.ro_rt); 667 ip6_forward_rt.ro_rt = NULL; 668 } 669 if (ipsrcchk_rt.ro_rt) { 670 RTFREE(ipsrcchk_rt.ro_rt); 671 ipsrcchk_rt.ro_rt = NULL; 672 } 673 #endif 674 675 crit_exit(); 676 } 677 678 /* 679 * Drain off all datagram fragments. 680 */ 681 void 682 frag6_drain(void) 683 { 684 if (frag6_doing_reass) 685 return; 686 while (ip6q.ip6q_next != &ip6q) { 687 ip6stat.ip6s_fragdropped++; 688 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 689 frag6_freef(ip6q.ip6q_next); 690 } 691 } 692