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 1.4 2004/03/09 14:57:18 hmp 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 46 #include <net/if.h> 47 #include <net/route.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_var.h> 51 #include <netinet/ip6.h> 52 #include <netinet6/ip6_var.h> 53 #include <netinet/icmp6.h> 54 55 #include <net/net_osdep.h> 56 57 /* 58 * Define it to get a correct behavior on per-interface statistics. 59 * You will need to perform an extra routing table lookup, per fragment, 60 * to do it. This may, or may not be, a performance hit. 61 */ 62 #define IN6_IFSTAT_STRICT 63 64 static void frag6_enq (struct ip6asfrag *, struct ip6asfrag *); 65 static void frag6_deq (struct ip6asfrag *); 66 static void frag6_insque (struct ip6q *, struct ip6q *); 67 static void frag6_remque (struct ip6q *); 68 static void frag6_freef (struct ip6q *); 69 70 /* XXX we eventually need splreass6, or some real semaphore */ 71 int frag6_doing_reass; 72 u_int frag6_nfragpackets; 73 struct ip6q ip6q; /* ip6 reassemble queue */ 74 75 /* FreeBSD tweak */ 76 MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 77 78 /* 79 * Initialise reassembly queue and fragment identifier. 80 */ 81 void 82 frag6_init() 83 { 84 struct timeval tv; 85 86 ip6_maxfragpackets = nmbclusters / 4; 87 88 /* 89 * in many cases, random() here does NOT return random number 90 * as initialization during bootstrap time occur in fixed order. 91 */ 92 microtime(&tv); 93 ip6_id = random() ^ tv.tv_usec; 94 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 95 } 96 97 /* 98 * In RFC2460, fragment and reassembly rule do not agree with each other, 99 * in terms of next header field handling in fragment header. 100 * While the sender will use the same value for all of the fragmented packets, 101 * receiver is suggested not to check the consistency. 102 * 103 * fragment rule (p20): 104 * (2) A Fragment header containing: 105 * The Next Header value that identifies the first header of 106 * the Fragmentable Part of the original packet. 107 * -> next header field is same for all fragments 108 * 109 * reassembly rule (p21): 110 * The Next Header field of the last header of the Unfragmentable 111 * Part is obtained from the Next Header field of the first 112 * fragment's Fragment header. 113 * -> should grab it from the first fragment only 114 * 115 * The following note also contradicts with fragment rule - noone is going to 116 * send different fragment with different next header field. 117 * 118 * additional note (p22): 119 * The Next Header values in the Fragment headers of different 120 * fragments of the same original packet may differ. Only the value 121 * from the Offset zero fragment packet is used for reassembly. 122 * -> should grab it from the first fragment only 123 * 124 * There is no explicit reason given in the RFC. Historical reason maybe? 125 */ 126 /* 127 * Fragment input 128 */ 129 int 130 frag6_input(mp, offp, proto) 131 struct mbuf **mp; 132 int *offp, proto; 133 { 134 struct mbuf *m = *mp, *t; 135 struct ip6_hdr *ip6; 136 struct ip6_frag *ip6f; 137 struct ip6q *q6; 138 struct ip6asfrag *af6, *ip6af, *af6dwn; 139 int offset = *offp, nxt, i, next; 140 int first_frag = 0; 141 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 142 struct ifnet *dstifp; 143 #ifdef IN6_IFSTAT_STRICT 144 static struct route_in6 ro; 145 struct sockaddr_in6 *dst; 146 #endif 147 148 ip6 = mtod(m, struct ip6_hdr *); 149 #ifndef PULLDOWN_TEST 150 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 151 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 152 #else 153 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 154 if (ip6f == NULL) 155 return IPPROTO_DONE; 156 #endif 157 158 dstifp = NULL; 159 #ifdef IN6_IFSTAT_STRICT 160 /* find the destination interface of the packet. */ 161 dst = (struct sockaddr_in6 *)&ro.ro_dst; 162 if (ro.ro_rt 163 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 164 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 165 RTFREE(ro.ro_rt); 166 ro.ro_rt = (struct rtentry *)0; 167 } 168 if (ro.ro_rt == NULL) { 169 bzero(dst, sizeof(*dst)); 170 dst->sin6_family = AF_INET6; 171 dst->sin6_len = sizeof(struct sockaddr_in6); 172 dst->sin6_addr = ip6->ip6_dst; 173 } 174 rtalloc((struct route *)&ro); 175 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 176 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 177 #else 178 /* we are violating the spec, this is not the destination interface */ 179 if ((m->m_flags & M_PKTHDR) != 0) 180 dstifp = m->m_pkthdr.rcvif; 181 #endif 182 183 /* jumbo payload can't contain a fragment header */ 184 if (ip6->ip6_plen == 0) { 185 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 186 in6_ifstat_inc(dstifp, ifs6_reass_fail); 187 return IPPROTO_DONE; 188 } 189 190 /* 191 * check whether fragment packet's fragment length is 192 * multiple of 8 octets. 193 * sizeof(struct ip6_frag) == 8 194 * sizeof(struct ip6_hdr) = 40 195 */ 196 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 197 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 198 icmp6_error(m, ICMP6_PARAM_PROB, 199 ICMP6_PARAMPROB_HEADER, 200 offsetof(struct ip6_hdr, ip6_plen)); 201 in6_ifstat_inc(dstifp, ifs6_reass_fail); 202 return IPPROTO_DONE; 203 } 204 205 ip6stat.ip6s_fragments++; 206 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 207 208 /* offset now points to data portion */ 209 offset += sizeof(struct ip6_frag); 210 211 frag6_doing_reass = 1; 212 213 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 214 if (ip6f->ip6f_ident == q6->ip6q_ident && 215 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 216 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 217 break; 218 219 if (q6 == &ip6q) { 220 /* 221 * the first fragment to arrive, create a reassembly queue. 222 */ 223 first_frag = 1; 224 225 /* 226 * Enforce upper bound on number of fragmented packets 227 * for which we attempt reassembly; 228 * If maxfrag is 0, never accept fragments. 229 * If maxfrag is -1, accept all fragments without limitation. 230 */ 231 if (ip6_maxfragpackets < 0) 232 ; 233 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 234 goto dropfrag; 235 frag6_nfragpackets++; 236 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 237 M_NOWAIT); 238 if (q6 == NULL) 239 goto dropfrag; 240 bzero(q6, sizeof(*q6)); 241 242 frag6_insque(q6, &ip6q); 243 244 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 245 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 246 #ifdef notyet 247 q6->ip6q_nxtp = (u_char *)nxtp; 248 #endif 249 q6->ip6q_ident = ip6f->ip6f_ident; 250 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 251 q6->ip6q_ttl = IPV6_FRAGTTL; 252 q6->ip6q_src = ip6->ip6_src; 253 q6->ip6q_dst = ip6->ip6_dst; 254 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 255 } 256 257 /* 258 * If it's the 1st fragment, record the length of the 259 * unfragmentable part and the next header of the fragment header. 260 */ 261 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 262 if (fragoff == 0) { 263 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 264 - sizeof(struct ip6_frag); 265 q6->ip6q_nxt = ip6f->ip6f_nxt; 266 } 267 268 /* 269 * Check that the reassembled packet would not exceed 65535 bytes 270 * in size. 271 * If it would exceed, discard the fragment and return an ICMP error. 272 */ 273 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 274 if (q6->ip6q_unfrglen >= 0) { 275 /* The 1st fragment has already arrived. */ 276 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 277 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 278 offset - sizeof(struct ip6_frag) + 279 offsetof(struct ip6_frag, ip6f_offlg)); 280 frag6_doing_reass = 0; 281 return(IPPROTO_DONE); 282 } 283 } 284 else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 285 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 286 offset - sizeof(struct ip6_frag) + 287 offsetof(struct ip6_frag, ip6f_offlg)); 288 frag6_doing_reass = 0; 289 return(IPPROTO_DONE); 290 } 291 /* 292 * If it's the first fragment, do the above check for each 293 * fragment already stored in the reassembly queue. 294 */ 295 if (fragoff == 0) { 296 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 297 af6 = af6dwn) { 298 af6dwn = af6->ip6af_down; 299 300 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 301 IPV6_MAXPACKET) { 302 struct mbuf *merr = IP6_REASS_MBUF(af6); 303 struct ip6_hdr *ip6err; 304 int erroff = af6->ip6af_offset; 305 306 /* dequeue the fragment. */ 307 frag6_deq(af6); 308 free(af6, M_FTABLE); 309 310 /* adjust pointer. */ 311 ip6err = mtod(merr, struct ip6_hdr *); 312 313 /* 314 * Restore source and destination addresses 315 * in the erroneous IPv6 header. 316 */ 317 ip6err->ip6_src = q6->ip6q_src; 318 ip6err->ip6_dst = q6->ip6q_dst; 319 320 icmp6_error(merr, ICMP6_PARAM_PROB, 321 ICMP6_PARAMPROB_HEADER, 322 erroff - sizeof(struct ip6_frag) + 323 offsetof(struct ip6_frag, ip6f_offlg)); 324 } 325 } 326 } 327 328 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 329 M_NOWAIT); 330 if (ip6af == NULL) 331 goto dropfrag; 332 bzero(ip6af, sizeof(*ip6af)); 333 ip6af->ip6af_head = ip6->ip6_flow; 334 ip6af->ip6af_len = ip6->ip6_plen; 335 ip6af->ip6af_nxt = ip6->ip6_nxt; 336 ip6af->ip6af_hlim = ip6->ip6_hlim; 337 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 338 ip6af->ip6af_off = fragoff; 339 ip6af->ip6af_frglen = frgpartlen; 340 ip6af->ip6af_offset = offset; 341 IP6_REASS_MBUF(ip6af) = m; 342 343 if (first_frag) { 344 af6 = (struct ip6asfrag *)q6; 345 goto insert; 346 } 347 348 /* 349 * Find a segment which begins after this one does. 350 */ 351 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 352 af6 = af6->ip6af_down) 353 if (af6->ip6af_off > ip6af->ip6af_off) 354 break; 355 356 #if 0 357 /* 358 * If there is a preceding segment, it may provide some of 359 * our data already. If so, drop the data from the incoming 360 * segment. If it provides all of our data, drop us. 361 */ 362 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 363 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 364 - ip6af->ip6af_off; 365 if (i > 0) { 366 if (i >= ip6af->ip6af_frglen) 367 goto dropfrag; 368 m_adj(IP6_REASS_MBUF(ip6af), i); 369 ip6af->ip6af_off += i; 370 ip6af->ip6af_frglen -= i; 371 } 372 } 373 374 /* 375 * While we overlap succeeding segments trim them or, 376 * if they are completely covered, dequeue them. 377 */ 378 while (af6 != (struct ip6asfrag *)q6 && 379 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 380 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 381 if (i < af6->ip6af_frglen) { 382 af6->ip6af_frglen -= i; 383 af6->ip6af_off += i; 384 m_adj(IP6_REASS_MBUF(af6), i); 385 break; 386 } 387 af6 = af6->ip6af_down; 388 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 389 frag6_deq(af6->ip6af_up); 390 } 391 #else 392 /* 393 * If the incoming framgent overlaps some existing fragments in 394 * the reassembly queue, drop it, since it is dangerous to override 395 * existing fragments from a security point of view. 396 */ 397 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 398 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 399 - ip6af->ip6af_off; 400 if (i > 0) { 401 #if 0 /* suppress the noisy log */ 402 log(LOG_ERR, "%d bytes of a fragment from %s " 403 "overlaps the previous fragment\n", 404 i, ip6_sprintf(&q6->ip6q_src)); 405 #endif 406 free(ip6af, M_FTABLE); 407 goto dropfrag; 408 } 409 } 410 if (af6 != (struct ip6asfrag *)q6) { 411 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 412 if (i > 0) { 413 #if 0 /* suppress the noisy log */ 414 log(LOG_ERR, "%d bytes of a fragment from %s " 415 "overlaps the succeeding fragment", 416 i, ip6_sprintf(&q6->ip6q_src)); 417 #endif 418 free(ip6af, M_FTABLE); 419 goto dropfrag; 420 } 421 } 422 #endif 423 424 insert: 425 426 /* 427 * Stick new segment in its place; 428 * check for complete reassembly. 429 * Move to front of packet queue, as we are 430 * the most recently active fragmented packet. 431 */ 432 frag6_enq(ip6af, af6->ip6af_up); 433 #if 0 /* xxx */ 434 if (q6 != ip6q.ip6q_next) { 435 frag6_remque(q6); 436 frag6_insque(q6, &ip6q); 437 } 438 #endif 439 next = 0; 440 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 441 af6 = af6->ip6af_down) { 442 if (af6->ip6af_off != next) { 443 frag6_doing_reass = 0; 444 return IPPROTO_DONE; 445 } 446 next += af6->ip6af_frglen; 447 } 448 if (af6->ip6af_up->ip6af_mff) { 449 frag6_doing_reass = 0; 450 return IPPROTO_DONE; 451 } 452 453 /* 454 * Reassembly is complete; concatenate fragments. 455 */ 456 ip6af = q6->ip6q_down; 457 t = m = IP6_REASS_MBUF(ip6af); 458 af6 = ip6af->ip6af_down; 459 frag6_deq(ip6af); 460 while (af6 != (struct ip6asfrag *)q6) { 461 af6dwn = af6->ip6af_down; 462 frag6_deq(af6); 463 while (t->m_next) 464 t = t->m_next; 465 t->m_next = IP6_REASS_MBUF(af6); 466 m_adj(t->m_next, af6->ip6af_offset); 467 free(af6, M_FTABLE); 468 af6 = af6dwn; 469 } 470 471 /* adjust offset to point where the original next header starts */ 472 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 473 free(ip6af, M_FTABLE); 474 ip6 = mtod(m, struct ip6_hdr *); 475 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 476 ip6->ip6_src = q6->ip6q_src; 477 ip6->ip6_dst = q6->ip6q_dst; 478 nxt = q6->ip6q_nxt; 479 #ifdef notyet 480 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 481 #endif 482 483 /* 484 * Delete frag6 header with as a few cost as possible. 485 */ 486 if (offset < m->m_len) { 487 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 488 offset); 489 m->m_data += sizeof(struct ip6_frag); 490 m->m_len -= sizeof(struct ip6_frag); 491 } else { 492 /* this comes with no copy if the boundary is on cluster */ 493 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 494 frag6_remque(q6); 495 free(q6, M_FTABLE); 496 frag6_nfragpackets--; 497 goto dropfrag; 498 } 499 m_adj(t, sizeof(struct ip6_frag)); 500 m_cat(m, t); 501 } 502 503 /* 504 * Store NXT to the original. 505 */ 506 { 507 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 508 *prvnxtp = nxt; 509 } 510 511 frag6_remque(q6); 512 free(q6, M_FTABLE); 513 frag6_nfragpackets--; 514 515 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 516 int plen = 0; 517 for (t = m; t; t = t->m_next) 518 plen += t->m_len; 519 m->m_pkthdr.len = plen; 520 } 521 522 ip6stat.ip6s_reassembled++; 523 in6_ifstat_inc(dstifp, ifs6_reass_ok); 524 525 /* 526 * Tell launch routine the next header 527 */ 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(q6) 549 struct ip6q *q6; 550 { 551 struct ip6asfrag *af6, *down6; 552 553 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 554 af6 = down6) { 555 struct mbuf *m = IP6_REASS_MBUF(af6); 556 557 down6 = af6->ip6af_down; 558 frag6_deq(af6); 559 560 /* 561 * Return ICMP time exceeded error for the 1st fragment. 562 * Just free other fragments. 563 */ 564 if (af6->ip6af_off == 0) { 565 struct ip6_hdr *ip6; 566 567 /* adjust pointer */ 568 ip6 = mtod(m, struct ip6_hdr *); 569 570 /* restoure source and destination addresses */ 571 ip6->ip6_src = q6->ip6q_src; 572 ip6->ip6_dst = q6->ip6q_dst; 573 574 icmp6_error(m, ICMP6_TIME_EXCEEDED, 575 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 576 } else 577 m_freem(m); 578 free(af6, M_FTABLE); 579 } 580 frag6_remque(q6); 581 free(q6, M_FTABLE); 582 frag6_nfragpackets--; 583 } 584 585 /* 586 * Put an ip fragment on a reassembly chain. 587 * Like insque, but pointers in middle of structure. 588 */ 589 void 590 frag6_enq(af6, up6) 591 struct ip6asfrag *af6, *up6; 592 { 593 af6->ip6af_up = up6; 594 af6->ip6af_down = up6->ip6af_down; 595 up6->ip6af_down->ip6af_up = af6; 596 up6->ip6af_down = af6; 597 } 598 599 /* 600 * To frag6_enq as remque is to insque. 601 */ 602 void 603 frag6_deq(af6) 604 struct ip6asfrag *af6; 605 { 606 af6->ip6af_up->ip6af_down = af6->ip6af_down; 607 af6->ip6af_down->ip6af_up = af6->ip6af_up; 608 } 609 610 void 611 frag6_insque(new, old) 612 struct ip6q *new, *old; 613 { 614 new->ip6q_prev = old; 615 new->ip6q_next = old->ip6q_next; 616 old->ip6q_next->ip6q_prev= new; 617 old->ip6q_next = new; 618 } 619 620 void 621 frag6_remque(p6) 622 struct ip6q *p6; 623 { 624 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 625 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 626 } 627 628 /* 629 * IPv6 reassembling timer processing; 630 * if a timer expires on a reassembly 631 * queue, discard it. 632 */ 633 void 634 frag6_slowtimo() 635 { 636 struct ip6q *q6; 637 int s = splnet(); 638 639 frag6_doing_reass = 1; 640 q6 = ip6q.ip6q_next; 641 if (q6) 642 while (q6 != &ip6q) { 643 --q6->ip6q_ttl; 644 q6 = q6->ip6q_next; 645 if (q6->ip6q_prev->ip6q_ttl == 0) { 646 ip6stat.ip6s_fragtimeout++; 647 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 648 frag6_freef(q6->ip6q_prev); 649 } 650 } 651 /* 652 * If we are over the maximum number of fragments 653 * (due to the limit being lowered), drain off 654 * enough to get down to the new limit. 655 */ 656 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 657 ip6q.ip6q_prev) { 658 ip6stat.ip6s_fragoverflow++; 659 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 660 frag6_freef(ip6q.ip6q_prev); 661 } 662 frag6_doing_reass = 0; 663 664 #if 0 665 /* 666 * Routing changes might produce a better route than we last used; 667 * make sure we notice eventually, even if forwarding only for one 668 * destination and the cache is never replaced. 669 */ 670 if (ip6_forward_rt.ro_rt) { 671 RTFREE(ip6_forward_rt.ro_rt); 672 ip6_forward_rt.ro_rt = 0; 673 } 674 if (ipsrcchk_rt.ro_rt) { 675 RTFREE(ipsrcchk_rt.ro_rt); 676 ipsrcchk_rt.ro_rt = 0; 677 } 678 #endif 679 680 splx(s); 681 } 682 683 /* 684 * Drain off all datagram fragments. 685 */ 686 void 687 frag6_drain() 688 { 689 if (frag6_doing_reass) 690 return; 691 while (ip6q.ip6q_next != &ip6q) { 692 ip6stat.ip6s_fragdropped++; 693 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 694 frag6_freef(ip6q.ip6q_next); 695 } 696 } 697