frag6.c revision 120643
1/* $FreeBSD: head/sys/netinet6/frag6.c 120643 2003-10-01 18:23:27Z 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 <sys/param.h> 34#include <sys/systm.h> 35#include <sys/malloc.h> 36#include <sys/mbuf.h> 37#include <sys/domain.h> 38#include <sys/protosw.h> 39#include <sys/socket.h> 40#include <sys/errno.h> 41#include <sys/time.h> 42#include <sys/kernel.h> 43#include <sys/syslog.h> 44 45#include <net/if.h> 46#include <net/route.h> 47 48#include <netinet/in.h> 49#include <netinet/in_var.h> 50#include <netinet/ip6.h> 51#include <netinet6/ip6_var.h> 52#include <netinet/icmp6.h> 53 54#include <net/net_osdep.h> 55 56/* 57 * Define it to get a correct behavior on per-interface statistics. 58 * You will need to perform an extra routing table lookup, per fragment, 59 * to do it. This may, or may not be, a performance hit. 60 */ 61#define IN6_IFSTAT_STRICT 62 63static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 64static void frag6_deq __P((struct ip6asfrag *)); 65static void frag6_insque __P((struct ip6q *, struct ip6q *)); 66static void frag6_remque __P((struct ip6q *)); 67static void frag6_freef __P((struct ip6q *)); 68 69/* XXX we eventually need splreass6, or some real semaphore */ 70int frag6_doing_reass; 71u_int frag6_nfragpackets; 72struct ip6q ip6q; /* ip6 reassemble queue */ 73 74/* FreeBSD tweak */ 75static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 76 77/* 78 * Initialise reassembly queue and fragment identifier. 79 */ 80void 81frag6_init() 82{ 83 struct timeval tv; 84 85 ip6_maxfragpackets = nmbclusters / 4; 86 87 /* 88 * in many cases, random() here does NOT return random number 89 * as initialization during bootstrap time occur in fixed order. 90 */ 91 microtime(&tv); 92#ifndef RANDOM_IP_ID 93 ip6_id = random() ^ tv.tv_usec; 94#endif 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 */ 130int 131frag6_input(mp, offp, proto) 132 struct mbuf **mp; 133 int *offp, proto; 134{ 135 struct mbuf *m = *mp, *t; 136 struct ip6_hdr *ip6; 137 struct ip6_frag *ip6f; 138 struct ip6q *q6; 139 struct ip6asfrag *af6, *ip6af, *af6dwn; 140 int offset = *offp, nxt, i, next; 141 int first_frag = 0; 142 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 143 struct ifnet *dstifp; 144#ifdef IN6_IFSTAT_STRICT 145 static struct route_in6 ro; 146 struct sockaddr_in6 *dst; 147#endif 148 149 ip6 = mtod(m, struct ip6_hdr *); 150#ifndef PULLDOWN_TEST 151 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 152 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 153#else 154 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 155 if (ip6f == NULL) 156 return IPPROTO_DONE; 157#endif 158 159 dstifp = NULL; 160#ifdef IN6_IFSTAT_STRICT 161 /* find the destination interface of the packet. */ 162 dst = (struct sockaddr_in6 *)&ro.ro_dst; 163 if (ro.ro_rt 164 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 165 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 166 RTFREE(ro.ro_rt); 167 ro.ro_rt = (struct rtentry *)0; 168 } 169 if (ro.ro_rt == NULL) { 170 bzero(dst, sizeof(*dst)); 171 dst->sin6_family = AF_INET6; 172 dst->sin6_len = sizeof(struct sockaddr_in6); 173 dst->sin6_addr = ip6->ip6_dst; 174 } 175 rtalloc((struct route *)&ro); 176 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 177 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 178#else 179 /* we are violating the spec, this is not the destination interface */ 180 if ((m->m_flags & M_PKTHDR) != 0) 181 dstifp = m->m_pkthdr.rcvif; 182#endif 183 184 /* jumbo payload can't contain a fragment header */ 185 if (ip6->ip6_plen == 0) { 186 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 187 in6_ifstat_inc(dstifp, ifs6_reass_fail); 188 return IPPROTO_DONE; 189 } 190 191 /* 192 * check whether fragment packet's fragment length is 193 * multiple of 8 octets. 194 * sizeof(struct ip6_frag) == 8 195 * sizeof(struct ip6_hdr) = 40 196 */ 197 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 198 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 199 icmp6_error(m, ICMP6_PARAM_PROB, 200 ICMP6_PARAMPROB_HEADER, 201 offsetof(struct ip6_hdr, ip6_plen)); 202 in6_ifstat_inc(dstifp, ifs6_reass_fail); 203 return IPPROTO_DONE; 204 } 205 206 ip6stat.ip6s_fragments++; 207 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 208 209 /* offset now points to data portion */ 210 offset += sizeof(struct ip6_frag); 211 212 frag6_doing_reass = 1; 213 214 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 215 if (ip6f->ip6f_ident == q6->ip6q_ident && 216 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 217 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 218 break; 219 220 if (q6 == &ip6q) { 221 /* 222 * the first fragment to arrive, create a reassembly queue. 223 */ 224 first_frag = 1; 225 226 /* 227 * Enforce upper bound on number of fragmented packets 228 * for which we attempt reassembly; 229 * If maxfrag is 0, never accept fragments. 230 * If maxfrag is -1, accept all fragments without limitation. 231 */ 232 if (ip6_maxfragpackets < 0) 233 ; 234 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 235 goto dropfrag; 236 frag6_nfragpackets++; 237 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 238 M_DONTWAIT); 239 if (q6 == NULL) 240 goto dropfrag; 241 bzero(q6, sizeof(*q6)); 242 243 frag6_insque(q6, &ip6q); 244 245 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 246 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 247#ifdef notyet 248 q6->ip6q_nxtp = (u_char *)nxtp; 249#endif 250 q6->ip6q_ident = ip6f->ip6f_ident; 251 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 252 q6->ip6q_ttl = IPV6_FRAGTTL; 253 q6->ip6q_src = ip6->ip6_src; 254 q6->ip6q_dst = ip6->ip6_dst; 255 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 256 } 257 258 /* 259 * If it's the 1st fragment, record the length of the 260 * unfragmentable part and the next header of the fragment header. 261 */ 262 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 263 if (fragoff == 0) { 264 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 265 - sizeof(struct ip6_frag); 266 q6->ip6q_nxt = ip6f->ip6f_nxt; 267 } 268 269 /* 270 * Check that the reassembled packet would not exceed 65535 bytes 271 * in size. 272 * If it would exceed, discard the fragment and return an ICMP error. 273 */ 274 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 275 if (q6->ip6q_unfrglen >= 0) { 276 /* The 1st fragment has already arrived. */ 277 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 278 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 279 offset - sizeof(struct ip6_frag) + 280 offsetof(struct ip6_frag, ip6f_offlg)); 281 frag6_doing_reass = 0; 282 return(IPPROTO_DONE); 283 } 284 } 285 else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 286 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 287 offset - sizeof(struct ip6_frag) + 288 offsetof(struct ip6_frag, ip6f_offlg)); 289 frag6_doing_reass = 0; 290 return(IPPROTO_DONE); 291 } 292 /* 293 * If it's the first fragment, do the above check for each 294 * fragment already stored in the reassembly queue. 295 */ 296 if (fragoff == 0) { 297 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 298 af6 = af6dwn) { 299 af6dwn = af6->ip6af_down; 300 301 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 302 IPV6_MAXPACKET) { 303 struct mbuf *merr = IP6_REASS_MBUF(af6); 304 struct ip6_hdr *ip6err; 305 int erroff = af6->ip6af_offset; 306 307 /* dequeue the fragment. */ 308 frag6_deq(af6); 309 free(af6, M_FTABLE); 310 311 /* adjust pointer. */ 312 ip6err = mtod(merr, struct ip6_hdr *); 313 314 /* 315 * Restore source and destination addresses 316 * in the erroneous IPv6 header. 317 */ 318 ip6err->ip6_src = q6->ip6q_src; 319 ip6err->ip6_dst = q6->ip6q_dst; 320 321 icmp6_error(merr, ICMP6_PARAM_PROB, 322 ICMP6_PARAMPROB_HEADER, 323 erroff - sizeof(struct ip6_frag) + 324 offsetof(struct ip6_frag, ip6f_offlg)); 325 } 326 } 327 } 328 329 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 330 M_DONTWAIT); 331 if (ip6af == NULL) 332 goto dropfrag; 333 bzero(ip6af, sizeof(*ip6af)); 334 ip6af->ip6af_head = ip6->ip6_flow; 335 ip6af->ip6af_len = ip6->ip6_plen; 336 ip6af->ip6af_nxt = ip6->ip6_nxt; 337 ip6af->ip6af_hlim = ip6->ip6_hlim; 338 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 339 ip6af->ip6af_off = fragoff; 340 ip6af->ip6af_frglen = frgpartlen; 341 ip6af->ip6af_offset = offset; 342 IP6_REASS_MBUF(ip6af) = m; 343 344 if (first_frag) { 345 af6 = (struct ip6asfrag *)q6; 346 goto insert; 347 } 348 349 /* 350 * Find a segment which begins after this one does. 351 */ 352 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 353 af6 = af6->ip6af_down) 354 if (af6->ip6af_off > ip6af->ip6af_off) 355 break; 356 357#if 0 358 /* 359 * If there is a preceding segment, it may provide some of 360 * our data already. If so, drop the data from the incoming 361 * segment. If it provides all of our data, drop us. 362 */ 363 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 364 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 365 - ip6af->ip6af_off; 366 if (i > 0) { 367 if (i >= ip6af->ip6af_frglen) 368 goto dropfrag; 369 m_adj(IP6_REASS_MBUF(ip6af), i); 370 ip6af->ip6af_off += i; 371 ip6af->ip6af_frglen -= i; 372 } 373 } 374 375 /* 376 * While we overlap succeeding segments trim them or, 377 * if they are completely covered, dequeue them. 378 */ 379 while (af6 != (struct ip6asfrag *)q6 && 380 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 381 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 382 if (i < af6->ip6af_frglen) { 383 af6->ip6af_frglen -= i; 384 af6->ip6af_off += i; 385 m_adj(IP6_REASS_MBUF(af6), i); 386 break; 387 } 388 af6 = af6->ip6af_down; 389 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 390 frag6_deq(af6->ip6af_up); 391 } 392#else 393 /* 394 * If the incoming framgent overlaps some existing fragments in 395 * the reassembly queue, drop it, since it is dangerous to override 396 * existing fragments from a security point of view. 397 */ 398 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 399 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 400 - ip6af->ip6af_off; 401 if (i > 0) { 402#if 0 /* suppress the noisy log */ 403 log(LOG_ERR, "%d bytes of a fragment from %s " 404 "overlaps the previous fragment\n", 405 i, ip6_sprintf(&q6->ip6q_src)); 406#endif 407 free(ip6af, M_FTABLE); 408 goto dropfrag; 409 } 410 } 411 if (af6 != (struct ip6asfrag *)q6) { 412 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 413 if (i > 0) { 414#if 0 /* suppress the noisy log */ 415 log(LOG_ERR, "%d bytes of a fragment from %s " 416 "overlaps the succeeding fragment", 417 i, ip6_sprintf(&q6->ip6q_src)); 418#endif 419 free(ip6af, M_FTABLE); 420 goto dropfrag; 421 } 422 } 423#endif 424 425insert: 426 427 /* 428 * Stick new segment in its place; 429 * check for complete reassembly. 430 * Move to front of packet queue, as we are 431 * the most recently active fragmented packet. 432 */ 433 frag6_enq(ip6af, af6->ip6af_up); 434#if 0 /* xxx */ 435 if (q6 != ip6q.ip6q_next) { 436 frag6_remque(q6); 437 frag6_insque(q6, &ip6q); 438 } 439#endif 440 next = 0; 441 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 442 af6 = af6->ip6af_down) { 443 if (af6->ip6af_off != next) { 444 frag6_doing_reass = 0; 445 return IPPROTO_DONE; 446 } 447 next += af6->ip6af_frglen; 448 } 449 if (af6->ip6af_up->ip6af_mff) { 450 frag6_doing_reass = 0; 451 return IPPROTO_DONE; 452 } 453 454 /* 455 * Reassembly is complete; concatenate fragments. 456 */ 457 ip6af = q6->ip6q_down; 458 t = m = IP6_REASS_MBUF(ip6af); 459 af6 = ip6af->ip6af_down; 460 frag6_deq(ip6af); 461 while (af6 != (struct ip6asfrag *)q6) { 462 af6dwn = af6->ip6af_down; 463 frag6_deq(af6); 464 while (t->m_next) 465 t = t->m_next; 466 t->m_next = IP6_REASS_MBUF(af6); 467 m_adj(t->m_next, af6->ip6af_offset); 468 free(af6, M_FTABLE); 469 af6 = af6dwn; 470 } 471 472 /* adjust offset to point where the original next header starts */ 473 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 474 free(ip6af, M_FTABLE); 475 ip6 = mtod(m, struct ip6_hdr *); 476 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 477 ip6->ip6_src = q6->ip6q_src; 478 ip6->ip6_dst = q6->ip6q_dst; 479 nxt = q6->ip6q_nxt; 480#ifdef notyet 481 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 482#endif 483 484 /* 485 * Delete frag6 header with as a few cost as possible. 486 */ 487 if (offset < m->m_len) { 488 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 489 offset); 490 m->m_data += sizeof(struct ip6_frag); 491 m->m_len -= sizeof(struct ip6_frag); 492 } else { 493 /* this comes with no copy if the boundary is on cluster */ 494 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 495 frag6_remque(q6); 496 free(q6, M_FTABLE); 497 frag6_nfragpackets--; 498 goto dropfrag; 499 } 500 m_adj(t, sizeof(struct ip6_frag)); 501 m_cat(m, t); 502 } 503 504 /* 505 * Store NXT to the original. 506 */ 507 { 508 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 509 *prvnxtp = nxt; 510 } 511 512 frag6_remque(q6); 513 free(q6, M_FTABLE); 514 frag6_nfragpackets--; 515 516 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 517 int plen = 0; 518 for (t = m; t; t = t->m_next) 519 plen += t->m_len; 520 m->m_pkthdr.len = plen; 521 } 522 523 ip6stat.ip6s_reassembled++; 524 in6_ifstat_inc(dstifp, ifs6_reass_ok); 525 526 /* 527 * Tell launch routine the next header 528 */ 529 530 *mp = m; 531 *offp = offset; 532 533 frag6_doing_reass = 0; 534 return nxt; 535 536 dropfrag: 537 in6_ifstat_inc(dstifp, ifs6_reass_fail); 538 ip6stat.ip6s_fragdropped++; 539 m_freem(m); 540 frag6_doing_reass = 0; 541 return IPPROTO_DONE; 542} 543 544/* 545 * Free a fragment reassembly header and all 546 * associated datagrams. 547 */ 548void 549frag6_freef(q6) 550 struct ip6q *q6; 551{ 552 struct ip6asfrag *af6, *down6; 553 554 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 555 af6 = down6) { 556 struct mbuf *m = IP6_REASS_MBUF(af6); 557 558 down6 = af6->ip6af_down; 559 frag6_deq(af6); 560 561 /* 562 * Return ICMP time exceeded error for the 1st fragment. 563 * Just free other fragments. 564 */ 565 if (af6->ip6af_off == 0) { 566 struct ip6_hdr *ip6; 567 568 /* adjust pointer */ 569 ip6 = mtod(m, struct ip6_hdr *); 570 571 /* restoure source and destination addresses */ 572 ip6->ip6_src = q6->ip6q_src; 573 ip6->ip6_dst = q6->ip6q_dst; 574 575 icmp6_error(m, ICMP6_TIME_EXCEEDED, 576 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 577 } else 578 m_freem(m); 579 free(af6, M_FTABLE); 580 } 581 frag6_remque(q6); 582 free(q6, M_FTABLE); 583 frag6_nfragpackets--; 584} 585 586/* 587 * Put an ip fragment on a reassembly chain. 588 * Like insque, but pointers in middle of structure. 589 */ 590void 591frag6_enq(af6, up6) 592 struct ip6asfrag *af6, *up6; 593{ 594 af6->ip6af_up = up6; 595 af6->ip6af_down = up6->ip6af_down; 596 up6->ip6af_down->ip6af_up = af6; 597 up6->ip6af_down = af6; 598} 599 600/* 601 * To frag6_enq as remque is to insque. 602 */ 603void 604frag6_deq(af6) 605 struct ip6asfrag *af6; 606{ 607 af6->ip6af_up->ip6af_down = af6->ip6af_down; 608 af6->ip6af_down->ip6af_up = af6->ip6af_up; 609} 610 611void 612frag6_insque(new, old) 613 struct ip6q *new, *old; 614{ 615 new->ip6q_prev = old; 616 new->ip6q_next = old->ip6q_next; 617 old->ip6q_next->ip6q_prev= new; 618 old->ip6q_next = new; 619} 620 621void 622frag6_remque(p6) 623 struct ip6q *p6; 624{ 625 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 626 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 627} 628 629/* 630 * IPv6 reassembling timer processing; 631 * if a timer expires on a reassembly 632 * queue, discard it. 633 */ 634void 635frag6_slowtimo() 636{ 637 struct ip6q *q6; 638 int s = splnet(); 639 640 frag6_doing_reass = 1; 641 q6 = ip6q.ip6q_next; 642 if (q6) 643 while (q6 != &ip6q) { 644 --q6->ip6q_ttl; 645 q6 = q6->ip6q_next; 646 if (q6->ip6q_prev->ip6q_ttl == 0) { 647 ip6stat.ip6s_fragtimeout++; 648 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 649 frag6_freef(q6->ip6q_prev); 650 } 651 } 652 /* 653 * If we are over the maximum number of fragments 654 * (due to the limit being lowered), drain off 655 * enough to get down to the new limit. 656 */ 657 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 658 ip6q.ip6q_prev) { 659 ip6stat.ip6s_fragoverflow++; 660 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 661 frag6_freef(ip6q.ip6q_prev); 662 } 663 frag6_doing_reass = 0; 664 665#if 0 666 /* 667 * Routing changes might produce a better route than we last used; 668 * make sure we notice eventually, even if forwarding only for one 669 * destination and the cache is never replaced. 670 */ 671 if (ip6_forward_rt.ro_rt) { 672 RTFREE(ip6_forward_rt.ro_rt); 673 ip6_forward_rt.ro_rt = 0; 674 } 675 if (ipsrcchk_rt.ro_rt) { 676 RTFREE(ipsrcchk_rt.ro_rt); 677 ipsrcchk_rt.ro_rt = 0; 678 } 679#endif 680 681 splx(s); 682} 683 684/* 685 * Drain off all datagram fragments. 686 */ 687void 688frag6_drain() 689{ 690 if (frag6_doing_reass) 691 return; 692 while (ip6q.ip6q_next != &ip6q) { 693 ip6stat.ip6s_fragdropped++; 694 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 695 frag6_freef(ip6q.ip6q_next); 696 } 697} 698