frag6.c revision 120648
1/* $FreeBSD: head/sys/netinet6/frag6.c 120648 2003-10-01 21:10:02Z 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 71/* XXX we eventually need splreass6, or some real semaphore */ 72int frag6_doing_reass; 73u_int frag6_nfragpackets; 74struct ip6q ip6q; /* ip6 reassemble queue */ 75 76/* FreeBSD tweak */ 77static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 78 79/* 80 * Initialise reassembly queue and fragment identifier. 81 */ 82void 83frag6_init() 84{ 85 86 ip6_maxfragpackets = nmbclusters / 4; 87 88#ifndef RANDOM_IP_ID 89 ip6_id = arc4random(); 90#endif 91 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 92} 93 94/* 95 * In RFC2460, fragment and reassembly rule do not agree with each other, 96 * in terms of next header field handling in fragment header. 97 * While the sender will use the same value for all of the fragmented packets, 98 * receiver is suggested not to check the consistency. 99 * 100 * fragment rule (p20): 101 * (2) A Fragment header containing: 102 * The Next Header value that identifies the first header of 103 * the Fragmentable Part of the original packet. 104 * -> next header field is same for all fragments 105 * 106 * reassembly rule (p21): 107 * The Next Header field of the last header of the Unfragmentable 108 * Part is obtained from the Next Header field of the first 109 * fragment's Fragment header. 110 * -> should grab it from the first fragment only 111 * 112 * The following note also contradicts with fragment rule - noone is going to 113 * send different fragment with different next header field. 114 * 115 * additional note (p22): 116 * The Next Header values in the Fragment headers of different 117 * fragments of the same original packet may differ. Only the value 118 * from the Offset zero fragment packet is used for reassembly. 119 * -> should grab it from the first fragment only 120 * 121 * There is no explicit reason given in the RFC. Historical reason maybe? 122 */ 123/* 124 * Fragment input 125 */ 126int 127frag6_input(mp, offp, proto) 128 struct mbuf **mp; 129 int *offp, proto; 130{ 131 struct mbuf *m = *mp, *t; 132 struct ip6_hdr *ip6; 133 struct ip6_frag *ip6f; 134 struct ip6q *q6; 135 struct ip6asfrag *af6, *ip6af, *af6dwn; 136 int offset = *offp, nxt, i, next; 137 int first_frag = 0; 138 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 139 struct ifnet *dstifp; 140#ifdef IN6_IFSTAT_STRICT 141 static struct route_in6 ro; 142 struct sockaddr_in6 *dst; 143#endif 144 145 ip6 = mtod(m, struct ip6_hdr *); 146#ifndef PULLDOWN_TEST 147 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 148 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 149#else 150 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 151 if (ip6f == NULL) 152 return IPPROTO_DONE; 153#endif 154 155 dstifp = NULL; 156#ifdef IN6_IFSTAT_STRICT 157 /* find the destination interface of the packet. */ 158 dst = (struct sockaddr_in6 *)&ro.ro_dst; 159 if (ro.ro_rt 160 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 161 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 162 RTFREE(ro.ro_rt); 163 ro.ro_rt = (struct rtentry *)0; 164 } 165 if (ro.ro_rt == NULL) { 166 bzero(dst, sizeof(*dst)); 167 dst->sin6_family = AF_INET6; 168 dst->sin6_len = sizeof(struct sockaddr_in6); 169 dst->sin6_addr = ip6->ip6_dst; 170 } 171 rtalloc((struct route *)&ro); 172 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 173 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 174#else 175 /* we are violating the spec, this is not the destination interface */ 176 if ((m->m_flags & M_PKTHDR) != 0) 177 dstifp = m->m_pkthdr.rcvif; 178#endif 179 180 /* jumbo payload can't contain a fragment header */ 181 if (ip6->ip6_plen == 0) { 182 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 183 in6_ifstat_inc(dstifp, ifs6_reass_fail); 184 return IPPROTO_DONE; 185 } 186 187 /* 188 * check whether fragment packet's fragment length is 189 * multiple of 8 octets. 190 * sizeof(struct ip6_frag) == 8 191 * sizeof(struct ip6_hdr) = 40 192 */ 193 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 194 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 195 icmp6_error(m, ICMP6_PARAM_PROB, 196 ICMP6_PARAMPROB_HEADER, 197 offsetof(struct ip6_hdr, ip6_plen)); 198 in6_ifstat_inc(dstifp, ifs6_reass_fail); 199 return IPPROTO_DONE; 200 } 201 202 ip6stat.ip6s_fragments++; 203 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 204 205 /* offset now points to data portion */ 206 offset += sizeof(struct ip6_frag); 207 208 frag6_doing_reass = 1; 209 210 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 211 if (ip6f->ip6f_ident == q6->ip6q_ident && 212 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 213 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 214 break; 215 216 if (q6 == &ip6q) { 217 /* 218 * the first fragment to arrive, create a reassembly queue. 219 */ 220 first_frag = 1; 221 222 /* 223 * Enforce upper bound on number of fragmented packets 224 * for which we attempt reassembly; 225 * If maxfrag is 0, never accept fragments. 226 * If maxfrag is -1, accept all fragments without limitation. 227 */ 228 if (ip6_maxfragpackets < 0) 229 ; 230 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 231 goto dropfrag; 232 frag6_nfragpackets++; 233 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 234 M_DONTWAIT); 235 if (q6 == NULL) 236 goto dropfrag; 237 bzero(q6, sizeof(*q6)); 238 239 frag6_insque(q6, &ip6q); 240 241 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 242 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 243#ifdef notyet 244 q6->ip6q_nxtp = (u_char *)nxtp; 245#endif 246 q6->ip6q_ident = ip6f->ip6f_ident; 247 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 248 q6->ip6q_ttl = IPV6_FRAGTTL; 249 q6->ip6q_src = ip6->ip6_src; 250 q6->ip6q_dst = ip6->ip6_dst; 251 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 252 } 253 254 /* 255 * If it's the 1st fragment, record the length of the 256 * unfragmentable part and the next header of the fragment header. 257 */ 258 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 259 if (fragoff == 0) { 260 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 261 - sizeof(struct ip6_frag); 262 q6->ip6q_nxt = ip6f->ip6f_nxt; 263 } 264 265 /* 266 * Check that the reassembled packet would not exceed 65535 bytes 267 * in size. 268 * If it would exceed, discard the fragment and return an ICMP error. 269 */ 270 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 271 if (q6->ip6q_unfrglen >= 0) { 272 /* The 1st fragment has already arrived. */ 273 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 274 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 275 offset - sizeof(struct ip6_frag) + 276 offsetof(struct ip6_frag, ip6f_offlg)); 277 frag6_doing_reass = 0; 278 return(IPPROTO_DONE); 279 } 280 } 281 else if (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 frag6_doing_reass = 0; 286 return(IPPROTO_DONE); 287 } 288 /* 289 * If it's the first fragment, do the above check for each 290 * fragment already stored in the reassembly queue. 291 */ 292 if (fragoff == 0) { 293 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 294 af6 = af6dwn) { 295 af6dwn = af6->ip6af_down; 296 297 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 298 IPV6_MAXPACKET) { 299 struct mbuf *merr = IP6_REASS_MBUF(af6); 300 struct ip6_hdr *ip6err; 301 int erroff = af6->ip6af_offset; 302 303 /* dequeue the fragment. */ 304 frag6_deq(af6); 305 free(af6, M_FTABLE); 306 307 /* adjust pointer. */ 308 ip6err = mtod(merr, struct ip6_hdr *); 309 310 /* 311 * Restore source and destination addresses 312 * in the erroneous IPv6 header. 313 */ 314 ip6err->ip6_src = q6->ip6q_src; 315 ip6err->ip6_dst = q6->ip6q_dst; 316 317 icmp6_error(merr, ICMP6_PARAM_PROB, 318 ICMP6_PARAMPROB_HEADER, 319 erroff - sizeof(struct ip6_frag) + 320 offsetof(struct ip6_frag, ip6f_offlg)); 321 } 322 } 323 } 324 325 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 326 M_DONTWAIT); 327 if (ip6af == NULL) 328 goto dropfrag; 329 bzero(ip6af, sizeof(*ip6af)); 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 free(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 free(ip6af, M_FTABLE); 416 goto dropfrag; 417 } 418 } 419#endif 420 421insert: 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 free(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 free(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, M_DONTWAIT)) == NULL) { 491 frag6_remque(q6); 492 free(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 free(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 * Tell launch routine the next header 524 */ 525 526 *mp = m; 527 *offp = offset; 528 529 frag6_doing_reass = 0; 530 return nxt; 531 532 dropfrag: 533 in6_ifstat_inc(dstifp, ifs6_reass_fail); 534 ip6stat.ip6s_fragdropped++; 535 m_freem(m); 536 frag6_doing_reass = 0; 537 return IPPROTO_DONE; 538} 539 540/* 541 * Free a fragment reassembly header and all 542 * associated datagrams. 543 */ 544void 545frag6_freef(q6) 546 struct ip6q *q6; 547{ 548 struct ip6asfrag *af6, *down6; 549 550 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 551 af6 = down6) { 552 struct mbuf *m = IP6_REASS_MBUF(af6); 553 554 down6 = af6->ip6af_down; 555 frag6_deq(af6); 556 557 /* 558 * Return ICMP time exceeded error for the 1st fragment. 559 * Just free other fragments. 560 */ 561 if (af6->ip6af_off == 0) { 562 struct ip6_hdr *ip6; 563 564 /* adjust pointer */ 565 ip6 = mtod(m, struct ip6_hdr *); 566 567 /* restoure source and destination addresses */ 568 ip6->ip6_src = q6->ip6q_src; 569 ip6->ip6_dst = q6->ip6q_dst; 570 571 icmp6_error(m, ICMP6_TIME_EXCEEDED, 572 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 573 } else 574 m_freem(m); 575 free(af6, M_FTABLE); 576 } 577 frag6_remque(q6); 578 free(q6, M_FTABLE); 579 frag6_nfragpackets--; 580} 581 582/* 583 * Put an ip fragment on a reassembly chain. 584 * Like insque, but pointers in middle of structure. 585 */ 586void 587frag6_enq(af6, up6) 588 struct ip6asfrag *af6, *up6; 589{ 590 af6->ip6af_up = up6; 591 af6->ip6af_down = up6->ip6af_down; 592 up6->ip6af_down->ip6af_up = af6; 593 up6->ip6af_down = af6; 594} 595 596/* 597 * To frag6_enq as remque is to insque. 598 */ 599void 600frag6_deq(af6) 601 struct ip6asfrag *af6; 602{ 603 af6->ip6af_up->ip6af_down = af6->ip6af_down; 604 af6->ip6af_down->ip6af_up = af6->ip6af_up; 605} 606 607void 608frag6_insque(new, old) 609 struct ip6q *new, *old; 610{ 611 new->ip6q_prev = old; 612 new->ip6q_next = old->ip6q_next; 613 old->ip6q_next->ip6q_prev= new; 614 old->ip6q_next = new; 615} 616 617void 618frag6_remque(p6) 619 struct ip6q *p6; 620{ 621 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 622 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 623} 624 625/* 626 * IPv6 reassembling timer processing; 627 * if a timer expires on a reassembly 628 * queue, discard it. 629 */ 630void 631frag6_slowtimo() 632{ 633 struct ip6q *q6; 634 int s = splnet(); 635 636 frag6_doing_reass = 1; 637 q6 = ip6q.ip6q_next; 638 if (q6) 639 while (q6 != &ip6q) { 640 --q6->ip6q_ttl; 641 q6 = q6->ip6q_next; 642 if (q6->ip6q_prev->ip6q_ttl == 0) { 643 ip6stat.ip6s_fragtimeout++; 644 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 645 frag6_freef(q6->ip6q_prev); 646 } 647 } 648 /* 649 * If we are over the maximum number of fragments 650 * (due to the limit being lowered), drain off 651 * enough to get down to the new limit. 652 */ 653 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 654 ip6q.ip6q_prev) { 655 ip6stat.ip6s_fragoverflow++; 656 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 657 frag6_freef(ip6q.ip6q_prev); 658 } 659 frag6_doing_reass = 0; 660 661#if 0 662 /* 663 * Routing changes might produce a better route than we last used; 664 * make sure we notice eventually, even if forwarding only for one 665 * destination and the cache is never replaced. 666 */ 667 if (ip6_forward_rt.ro_rt) { 668 RTFREE(ip6_forward_rt.ro_rt); 669 ip6_forward_rt.ro_rt = 0; 670 } 671 if (ipsrcchk_rt.ro_rt) { 672 RTFREE(ipsrcchk_rt.ro_rt); 673 ipsrcchk_rt.ro_rt = 0; 674 } 675#endif 676 677 splx(s); 678} 679 680/* 681 * Drain off all datagram fragments. 682 */ 683void 684frag6_drain() 685{ 686 if (frag6_doing_reass) 687 return; 688 while (ip6q.ip6q_next != &ip6q) { 689 ip6stat.ip6s_fragdropped++; 690 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 691 frag6_freef(ip6q.ip6q_next); 692 } 693} 694