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 1.8 2005/06/03 19:56:08 eirikn 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 = random() ^ 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 = (struct rtentry *)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 *)malloc(sizeof(struct ip6q), M_FTABLE, 236 M_NOWAIT); 237 if (q6 == NULL) 238 goto dropfrag; 239 bzero(q6, sizeof(*q6)); 240 241 frag6_insque(q6, &ip6q); 242 243 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 244 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 245 #ifdef notyet 246 q6->ip6q_nxtp = (u_char *)nxtp; 247 #endif 248 q6->ip6q_ident = ip6f->ip6f_ident; 249 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 250 q6->ip6q_ttl = IPV6_FRAGTTL; 251 q6->ip6q_src = ip6->ip6_src; 252 q6->ip6q_dst = ip6->ip6_dst; 253 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 254 } 255 256 /* 257 * If it's the 1st fragment, record the length of the 258 * unfragmentable part and the next header of the fragment header. 259 */ 260 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 261 if (fragoff == 0) { 262 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) 263 - sizeof(struct ip6_frag); 264 q6->ip6q_nxt = ip6f->ip6f_nxt; 265 } 266 267 /* 268 * Check that the reassembled packet would not exceed 65535 bytes 269 * in size. 270 * If it would exceed, discard the fragment and return an ICMP error. 271 */ 272 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 273 if (q6->ip6q_unfrglen >= 0) { 274 /* The 1st fragment has already arrived. */ 275 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 276 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 277 offset - sizeof(struct ip6_frag) + 278 offsetof(struct ip6_frag, ip6f_offlg)); 279 frag6_doing_reass = 0; 280 return(IPPROTO_DONE); 281 } 282 } 283 else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 284 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 285 offset - sizeof(struct ip6_frag) + 286 offsetof(struct ip6_frag, ip6f_offlg)); 287 frag6_doing_reass = 0; 288 return(IPPROTO_DONE); 289 } 290 /* 291 * If it's the first fragment, do the above check for each 292 * fragment already stored in the reassembly queue. 293 */ 294 if (fragoff == 0) { 295 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 296 af6 = af6dwn) { 297 af6dwn = af6->ip6af_down; 298 299 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 300 IPV6_MAXPACKET) { 301 struct mbuf *merr = IP6_REASS_MBUF(af6); 302 struct ip6_hdr *ip6err; 303 int erroff = af6->ip6af_offset; 304 305 /* dequeue the fragment. */ 306 frag6_deq(af6); 307 free(af6, M_FTABLE); 308 309 /* adjust pointer. */ 310 ip6err = mtod(merr, struct ip6_hdr *); 311 312 /* 313 * Restore source and destination addresses 314 * in the erroneous IPv6 header. 315 */ 316 ip6err->ip6_src = q6->ip6q_src; 317 ip6err->ip6_dst = q6->ip6q_dst; 318 319 icmp6_error(merr, ICMP6_PARAM_PROB, 320 ICMP6_PARAMPROB_HEADER, 321 erroff - sizeof(struct ip6_frag) + 322 offsetof(struct ip6_frag, ip6f_offlg)); 323 } 324 } 325 } 326 327 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 328 M_NOWAIT); 329 if (ip6af == NULL) 330 goto dropfrag; 331 bzero(ip6af, sizeof(*ip6af)); 332 ip6af->ip6af_head = ip6->ip6_flow; 333 ip6af->ip6af_len = ip6->ip6_plen; 334 ip6af->ip6af_nxt = ip6->ip6_nxt; 335 ip6af->ip6af_hlim = ip6->ip6_hlim; 336 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 337 ip6af->ip6af_off = fragoff; 338 ip6af->ip6af_frglen = frgpartlen; 339 ip6af->ip6af_offset = offset; 340 IP6_REASS_MBUF(ip6af) = m; 341 342 if (first_frag) { 343 af6 = (struct ip6asfrag *)q6; 344 goto insert; 345 } 346 347 /* 348 * Find a segment which begins after this one does. 349 */ 350 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 351 af6 = af6->ip6af_down) 352 if (af6->ip6af_off > ip6af->ip6af_off) 353 break; 354 355 #if 0 356 /* 357 * If there is a preceding segment, it may provide some of 358 * our data already. If so, drop the data from the incoming 359 * segment. If it provides all of our data, drop us. 360 */ 361 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 362 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 363 - ip6af->ip6af_off; 364 if (i > 0) { 365 if (i >= ip6af->ip6af_frglen) 366 goto dropfrag; 367 m_adj(IP6_REASS_MBUF(ip6af), i); 368 ip6af->ip6af_off += i; 369 ip6af->ip6af_frglen -= i; 370 } 371 } 372 373 /* 374 * While we overlap succeeding segments trim them or, 375 * if they are completely covered, dequeue them. 376 */ 377 while (af6 != (struct ip6asfrag *)q6 && 378 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 379 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 380 if (i < af6->ip6af_frglen) { 381 af6->ip6af_frglen -= i; 382 af6->ip6af_off += i; 383 m_adj(IP6_REASS_MBUF(af6), i); 384 break; 385 } 386 af6 = af6->ip6af_down; 387 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 388 frag6_deq(af6->ip6af_up); 389 } 390 #else 391 /* 392 * If the incoming framgent overlaps some existing fragments in 393 * the reassembly queue, drop it, since it is dangerous to override 394 * existing fragments from a security point of view. 395 */ 396 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 397 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 398 - ip6af->ip6af_off; 399 if (i > 0) { 400 #if 0 /* suppress the noisy log */ 401 log(LOG_ERR, "%d bytes of a fragment from %s " 402 "overlaps the previous fragment\n", 403 i, ip6_sprintf(&q6->ip6q_src)); 404 #endif 405 free(ip6af, M_FTABLE); 406 goto dropfrag; 407 } 408 } 409 if (af6 != (struct ip6asfrag *)q6) { 410 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 411 if (i > 0) { 412 #if 0 /* suppress the noisy log */ 413 log(LOG_ERR, "%d bytes of a fragment from %s " 414 "overlaps the succeeding fragment", 415 i, ip6_sprintf(&q6->ip6q_src)); 416 #endif 417 free(ip6af, M_FTABLE); 418 goto dropfrag; 419 } 420 } 421 #endif 422 423 insert: 424 425 /* 426 * Stick new segment in its place; 427 * check for complete reassembly. 428 * Move to front of packet queue, as we are 429 * the most recently active fragmented packet. 430 */ 431 frag6_enq(ip6af, af6->ip6af_up); 432 #if 0 /* xxx */ 433 if (q6 != ip6q.ip6q_next) { 434 frag6_remque(q6); 435 frag6_insque(q6, &ip6q); 436 } 437 #endif 438 next = 0; 439 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 440 af6 = af6->ip6af_down) { 441 if (af6->ip6af_off != next) { 442 frag6_doing_reass = 0; 443 return IPPROTO_DONE; 444 } 445 next += af6->ip6af_frglen; 446 } 447 if (af6->ip6af_up->ip6af_mff) { 448 frag6_doing_reass = 0; 449 return IPPROTO_DONE; 450 } 451 452 /* 453 * Reassembly is complete; concatenate fragments. 454 */ 455 ip6af = q6->ip6q_down; 456 t = m = IP6_REASS_MBUF(ip6af); 457 af6 = ip6af->ip6af_down; 458 frag6_deq(ip6af); 459 while (af6 != (struct ip6asfrag *)q6) { 460 af6dwn = af6->ip6af_down; 461 frag6_deq(af6); 462 while (t->m_next) 463 t = t->m_next; 464 t->m_next = IP6_REASS_MBUF(af6); 465 m_adj(t->m_next, af6->ip6af_offset); 466 free(af6, M_FTABLE); 467 af6 = af6dwn; 468 } 469 470 /* adjust offset to point where the original next header starts */ 471 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 472 free(ip6af, M_FTABLE); 473 ip6 = mtod(m, struct ip6_hdr *); 474 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 475 ip6->ip6_src = q6->ip6q_src; 476 ip6->ip6_dst = q6->ip6q_dst; 477 nxt = q6->ip6q_nxt; 478 #ifdef notyet 479 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 480 #endif 481 482 /* 483 * Delete frag6 header with as a few cost as possible. 484 */ 485 if (offset < m->m_len) { 486 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 487 offset); 488 m->m_data += sizeof(struct ip6_frag); 489 m->m_len -= sizeof(struct ip6_frag); 490 } else { 491 /* this comes with no copy if the boundary is on cluster */ 492 if ((t = m_split(m, offset, MB_DONTWAIT)) == NULL) { 493 frag6_remque(q6); 494 free(q6, M_FTABLE); 495 frag6_nfragpackets--; 496 goto dropfrag; 497 } 498 m_adj(t, sizeof(struct ip6_frag)); 499 m_cat(m, t); 500 } 501 502 /* 503 * Store NXT to the original. 504 */ 505 { 506 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 507 *prvnxtp = nxt; 508 } 509 510 frag6_remque(q6); 511 free(q6, M_FTABLE); 512 frag6_nfragpackets--; 513 514 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 515 int plen = 0; 516 for (t = m; t; t = t->m_next) 517 plen += t->m_len; 518 m->m_pkthdr.len = plen; 519 } 520 521 ip6stat.ip6s_reassembled++; 522 in6_ifstat_inc(dstifp, ifs6_reass_ok); 523 524 /* 525 * Tell launch routine the next header 526 */ 527 528 *mp = m; 529 *offp = offset; 530 531 frag6_doing_reass = 0; 532 return nxt; 533 534 dropfrag: 535 in6_ifstat_inc(dstifp, ifs6_reass_fail); 536 ip6stat.ip6s_fragdropped++; 537 m_freem(m); 538 frag6_doing_reass = 0; 539 return IPPROTO_DONE; 540 } 541 542 /* 543 * Free a fragment reassembly header and all 544 * associated datagrams. 545 */ 546 void 547 frag6_freef(struct ip6q *q6) 548 { 549 struct ip6asfrag *af6, *down6; 550 551 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 552 af6 = down6) { 553 struct mbuf *m = IP6_REASS_MBUF(af6); 554 555 down6 = af6->ip6af_down; 556 frag6_deq(af6); 557 558 /* 559 * Return ICMP time exceeded error for the 1st fragment. 560 * Just free other fragments. 561 */ 562 if (af6->ip6af_off == 0) { 563 struct ip6_hdr *ip6; 564 565 /* adjust pointer */ 566 ip6 = mtod(m, struct ip6_hdr *); 567 568 /* restoure source and destination addresses */ 569 ip6->ip6_src = q6->ip6q_src; 570 ip6->ip6_dst = q6->ip6q_dst; 571 572 icmp6_error(m, ICMP6_TIME_EXCEEDED, 573 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 574 } else 575 m_freem(m); 576 free(af6, M_FTABLE); 577 } 578 frag6_remque(q6); 579 free(q6, M_FTABLE); 580 frag6_nfragpackets--; 581 } 582 583 /* 584 * Put an ip fragment on a reassembly chain. 585 * Like insque, but pointers in middle of structure. 586 */ 587 void 588 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *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 */ 599 void 600 frag6_deq(struct ip6asfrag *af6) 601 { 602 af6->ip6af_up->ip6af_down = af6->ip6af_down; 603 af6->ip6af_down->ip6af_up = af6->ip6af_up; 604 } 605 606 void 607 frag6_insque(struct ip6q *new, struct ip6q *old) 608 { 609 new->ip6q_prev = old; 610 new->ip6q_next = old->ip6q_next; 611 old->ip6q_next->ip6q_prev= new; 612 old->ip6q_next = new; 613 } 614 615 void 616 frag6_remque(struct ip6q *p6) 617 { 618 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 619 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 620 } 621 622 /* 623 * IPv6 reassembling timer processing; 624 * if a timer expires on a reassembly 625 * queue, discard it. 626 */ 627 void 628 frag6_slowtimo(void) 629 { 630 struct ip6q *q6; 631 632 crit_enter(); 633 frag6_doing_reass = 1; 634 q6 = ip6q.ip6q_next; 635 if (q6) 636 while (q6 != &ip6q) { 637 --q6->ip6q_ttl; 638 q6 = q6->ip6q_next; 639 if (q6->ip6q_prev->ip6q_ttl == 0) { 640 ip6stat.ip6s_fragtimeout++; 641 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 642 frag6_freef(q6->ip6q_prev); 643 } 644 } 645 /* 646 * If we are over the maximum number of fragments 647 * (due to the limit being lowered), drain off 648 * enough to get down to the new limit. 649 */ 650 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 651 ip6q.ip6q_prev) { 652 ip6stat.ip6s_fragoverflow++; 653 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 654 frag6_freef(ip6q.ip6q_prev); 655 } 656 frag6_doing_reass = 0; 657 658 #if 0 659 /* 660 * Routing changes might produce a better route than we last used; 661 * make sure we notice eventually, even if forwarding only for one 662 * destination and the cache is never replaced. 663 */ 664 if (ip6_forward_rt.ro_rt) { 665 RTFREE(ip6_forward_rt.ro_rt); 666 ip6_forward_rt.ro_rt = NULL; 667 } 668 if (ipsrcchk_rt.ro_rt) { 669 RTFREE(ipsrcchk_rt.ro_rt); 670 ipsrcchk_rt.ro_rt = NULL; 671 } 672 #endif 673 674 crit_exit(); 675 } 676 677 /* 678 * Drain off all datagram fragments. 679 */ 680 void 681 frag6_drain(void) 682 { 683 if (frag6_doing_reass) 684 return; 685 while (ip6q.ip6q_next != &ip6q) { 686 ip6stat.ip6s_fragdropped++; 687 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 688 frag6_freef(ip6q.ip6q_next); 689 } 690 } 691