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 1.6 2004/06/02 14:43:01 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 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(void) 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(struct mbuf **mp, int *offp, int proto) 131 { 132 struct mbuf *m = *mp, *t; 133 struct ip6_hdr *ip6; 134 struct ip6_frag *ip6f; 135 struct ip6q *q6; 136 struct ip6asfrag *af6, *ip6af, *af6dwn; 137 int offset = *offp, nxt, i, next; 138 int first_frag = 0; 139 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 140 struct ifnet *dstifp; 141 #ifdef IN6_IFSTAT_STRICT 142 static struct route_in6 ro; 143 struct sockaddr_in6 *dst; 144 #endif 145 146 ip6 = mtod(m, struct ip6_hdr *); 147 #ifndef PULLDOWN_TEST 148 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 149 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 150 #else 151 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 152 if (ip6f == NULL) 153 return IPPROTO_DONE; 154 #endif 155 156 dstifp = NULL; 157 #ifdef IN6_IFSTAT_STRICT 158 /* find the destination interface of the packet. */ 159 dst = (struct sockaddr_in6 *)&ro.ro_dst; 160 if (ro.ro_rt 161 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 162 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 163 RTFREE(ro.ro_rt); 164 ro.ro_rt = (struct rtentry *)0; 165 } 166 if (ro.ro_rt == NULL) { 167 bzero(dst, sizeof(*dst)); 168 dst->sin6_family = AF_INET6; 169 dst->sin6_len = sizeof(struct sockaddr_in6); 170 dst->sin6_addr = ip6->ip6_dst; 171 } 172 rtalloc((struct route *)&ro); 173 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 174 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 175 #else 176 /* we are violating the spec, this is not the destination interface */ 177 if ((m->m_flags & M_PKTHDR) != 0) 178 dstifp = m->m_pkthdr.rcvif; 179 #endif 180 181 /* jumbo payload can't contain a fragment header */ 182 if (ip6->ip6_plen == 0) { 183 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 184 in6_ifstat_inc(dstifp, ifs6_reass_fail); 185 return IPPROTO_DONE; 186 } 187 188 /* 189 * check whether fragment packet's fragment length is 190 * multiple of 8 octets. 191 * sizeof(struct ip6_frag) == 8 192 * sizeof(struct ip6_hdr) = 40 193 */ 194 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 195 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 196 icmp6_error(m, ICMP6_PARAM_PROB, 197 ICMP6_PARAMPROB_HEADER, 198 offsetof(struct ip6_hdr, ip6_plen)); 199 in6_ifstat_inc(dstifp, ifs6_reass_fail); 200 return IPPROTO_DONE; 201 } 202 203 ip6stat.ip6s_fragments++; 204 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 205 206 /* offset now points to data portion */ 207 offset += sizeof(struct ip6_frag); 208 209 frag6_doing_reass = 1; 210 211 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 212 if (ip6f->ip6f_ident == q6->ip6q_ident && 213 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 214 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 215 break; 216 217 if (q6 == &ip6q) { 218 /* 219 * the first fragment to arrive, create a reassembly queue. 220 */ 221 first_frag = 1; 222 223 /* 224 * Enforce upper bound on number of fragmented packets 225 * for which we attempt reassembly; 226 * If maxfrag is 0, never accept fragments. 227 * If maxfrag is -1, accept all fragments without limitation. 228 */ 229 if (ip6_maxfragpackets < 0) 230 ; 231 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 232 goto dropfrag; 233 frag6_nfragpackets++; 234 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 235 M_NOWAIT); 236 if (q6 == NULL) 237 goto dropfrag; 238 bzero(q6, sizeof(*q6)); 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 free(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 *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 327 M_NOWAIT); 328 if (ip6af == NULL) 329 goto dropfrag; 330 bzero(ip6af, sizeof(*ip6af)); 331 ip6af->ip6af_head = ip6->ip6_flow; 332 ip6af->ip6af_len = ip6->ip6_plen; 333 ip6af->ip6af_nxt = ip6->ip6_nxt; 334 ip6af->ip6af_hlim = ip6->ip6_hlim; 335 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 336 ip6af->ip6af_off = fragoff; 337 ip6af->ip6af_frglen = frgpartlen; 338 ip6af->ip6af_offset = offset; 339 IP6_REASS_MBUF(ip6af) = m; 340 341 if (first_frag) { 342 af6 = (struct ip6asfrag *)q6; 343 goto insert; 344 } 345 346 /* 347 * Find a segment which begins after this one does. 348 */ 349 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 350 af6 = af6->ip6af_down) 351 if (af6->ip6af_off > ip6af->ip6af_off) 352 break; 353 354 #if 0 355 /* 356 * If there is a preceding segment, it may provide some of 357 * our data already. If so, drop the data from the incoming 358 * segment. If it provides all of our data, drop us. 359 */ 360 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 361 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 362 - ip6af->ip6af_off; 363 if (i > 0) { 364 if (i >= ip6af->ip6af_frglen) 365 goto dropfrag; 366 m_adj(IP6_REASS_MBUF(ip6af), i); 367 ip6af->ip6af_off += i; 368 ip6af->ip6af_frglen -= i; 369 } 370 } 371 372 /* 373 * While we overlap succeeding segments trim them or, 374 * if they are completely covered, dequeue them. 375 */ 376 while (af6 != (struct ip6asfrag *)q6 && 377 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 378 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 379 if (i < af6->ip6af_frglen) { 380 af6->ip6af_frglen -= i; 381 af6->ip6af_off += i; 382 m_adj(IP6_REASS_MBUF(af6), i); 383 break; 384 } 385 af6 = af6->ip6af_down; 386 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 387 frag6_deq(af6->ip6af_up); 388 } 389 #else 390 /* 391 * If the incoming framgent overlaps some existing fragments in 392 * the reassembly queue, drop it, since it is dangerous to override 393 * existing fragments from a security point of view. 394 */ 395 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 396 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 397 - ip6af->ip6af_off; 398 if (i > 0) { 399 #if 0 /* suppress the noisy log */ 400 log(LOG_ERR, "%d bytes of a fragment from %s " 401 "overlaps the previous fragment\n", 402 i, ip6_sprintf(&q6->ip6q_src)); 403 #endif 404 free(ip6af, M_FTABLE); 405 goto dropfrag; 406 } 407 } 408 if (af6 != (struct ip6asfrag *)q6) { 409 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 410 if (i > 0) { 411 #if 0 /* suppress the noisy log */ 412 log(LOG_ERR, "%d bytes of a fragment from %s " 413 "overlaps the succeeding fragment", 414 i, ip6_sprintf(&q6->ip6q_src)); 415 #endif 416 free(ip6af, M_FTABLE); 417 goto dropfrag; 418 } 419 } 420 #endif 421 422 insert: 423 424 /* 425 * Stick new segment in its place; 426 * check for complete reassembly. 427 * Move to front of packet queue, as we are 428 * the most recently active fragmented packet. 429 */ 430 frag6_enq(ip6af, af6->ip6af_up); 431 #if 0 /* xxx */ 432 if (q6 != ip6q.ip6q_next) { 433 frag6_remque(q6); 434 frag6_insque(q6, &ip6q); 435 } 436 #endif 437 next = 0; 438 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 439 af6 = af6->ip6af_down) { 440 if (af6->ip6af_off != next) { 441 frag6_doing_reass = 0; 442 return IPPROTO_DONE; 443 } 444 next += af6->ip6af_frglen; 445 } 446 if (af6->ip6af_up->ip6af_mff) { 447 frag6_doing_reass = 0; 448 return IPPROTO_DONE; 449 } 450 451 /* 452 * Reassembly is complete; concatenate fragments. 453 */ 454 ip6af = q6->ip6q_down; 455 t = m = IP6_REASS_MBUF(ip6af); 456 af6 = ip6af->ip6af_down; 457 frag6_deq(ip6af); 458 while (af6 != (struct ip6asfrag *)q6) { 459 af6dwn = af6->ip6af_down; 460 frag6_deq(af6); 461 while (t->m_next) 462 t = t->m_next; 463 t->m_next = IP6_REASS_MBUF(af6); 464 m_adj(t->m_next, af6->ip6af_offset); 465 free(af6, M_FTABLE); 466 af6 = af6dwn; 467 } 468 469 /* adjust offset to point where the original next header starts */ 470 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 471 free(ip6af, M_FTABLE); 472 ip6 = mtod(m, struct ip6_hdr *); 473 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 474 ip6->ip6_src = q6->ip6q_src; 475 ip6->ip6_dst = q6->ip6q_dst; 476 nxt = q6->ip6q_nxt; 477 #ifdef notyet 478 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 479 #endif 480 481 /* 482 * Delete frag6 header with as a few cost as possible. 483 */ 484 if (offset < m->m_len) { 485 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 486 offset); 487 m->m_data += sizeof(struct ip6_frag); 488 m->m_len -= sizeof(struct ip6_frag); 489 } else { 490 /* this comes with no copy if the boundary is on cluster */ 491 if ((t = m_split(m, offset, MB_DONTWAIT)) == NULL) { 492 frag6_remque(q6); 493 free(q6, M_FTABLE); 494 frag6_nfragpackets--; 495 goto dropfrag; 496 } 497 m_adj(t, sizeof(struct ip6_frag)); 498 m_cat(m, t); 499 } 500 501 /* 502 * Store NXT to the original. 503 */ 504 { 505 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 506 *prvnxtp = nxt; 507 } 508 509 frag6_remque(q6); 510 free(q6, M_FTABLE); 511 frag6_nfragpackets--; 512 513 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 514 int plen = 0; 515 for (t = m; t; t = t->m_next) 516 plen += t->m_len; 517 m->m_pkthdr.len = plen; 518 } 519 520 ip6stat.ip6s_reassembled++; 521 in6_ifstat_inc(dstifp, ifs6_reass_ok); 522 523 /* 524 * Tell launch routine the next header 525 */ 526 527 *mp = m; 528 *offp = offset; 529 530 frag6_doing_reass = 0; 531 return nxt; 532 533 dropfrag: 534 in6_ifstat_inc(dstifp, ifs6_reass_fail); 535 ip6stat.ip6s_fragdropped++; 536 m_freem(m); 537 frag6_doing_reass = 0; 538 return IPPROTO_DONE; 539 } 540 541 /* 542 * Free a fragment reassembly header and all 543 * associated datagrams. 544 */ 545 void 546 frag6_freef(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 */ 586 void 587 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 588 { 589 af6->ip6af_up = up6; 590 af6->ip6af_down = up6->ip6af_down; 591 up6->ip6af_down->ip6af_up = af6; 592 up6->ip6af_down = af6; 593 } 594 595 /* 596 * To frag6_enq as remque is to insque. 597 */ 598 void 599 frag6_deq(struct ip6asfrag *af6) 600 { 601 af6->ip6af_up->ip6af_down = af6->ip6af_down; 602 af6->ip6af_down->ip6af_up = af6->ip6af_up; 603 } 604 605 void 606 frag6_insque(struct ip6q *new, struct ip6q *old) 607 { 608 new->ip6q_prev = old; 609 new->ip6q_next = old->ip6q_next; 610 old->ip6q_next->ip6q_prev= new; 611 old->ip6q_next = new; 612 } 613 614 void 615 frag6_remque(struct ip6q *p6) 616 { 617 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 618 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 619 } 620 621 /* 622 * IPv6 reassembling timer processing; 623 * if a timer expires on a reassembly 624 * queue, discard it. 625 */ 626 void 627 frag6_slowtimo(void) 628 { 629 struct ip6q *q6; 630 int s = splnet(); 631 632 frag6_doing_reass = 1; 633 q6 = ip6q.ip6q_next; 634 if (q6) 635 while (q6 != &ip6q) { 636 --q6->ip6q_ttl; 637 q6 = q6->ip6q_next; 638 if (q6->ip6q_prev->ip6q_ttl == 0) { 639 ip6stat.ip6s_fragtimeout++; 640 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 641 frag6_freef(q6->ip6q_prev); 642 } 643 } 644 /* 645 * If we are over the maximum number of fragments 646 * (due to the limit being lowered), drain off 647 * enough to get down to the new limit. 648 */ 649 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 650 ip6q.ip6q_prev) { 651 ip6stat.ip6s_fragoverflow++; 652 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 653 frag6_freef(ip6q.ip6q_prev); 654 } 655 frag6_doing_reass = 0; 656 657 #if 0 658 /* 659 * Routing changes might produce a better route than we last used; 660 * make sure we notice eventually, even if forwarding only for one 661 * destination and the cache is never replaced. 662 */ 663 if (ip6_forward_rt.ro_rt) { 664 RTFREE(ip6_forward_rt.ro_rt); 665 ip6_forward_rt.ro_rt = 0; 666 } 667 if (ipsrcchk_rt.ro_rt) { 668 RTFREE(ipsrcchk_rt.ro_rt); 669 ipsrcchk_rt.ro_rt = 0; 670 } 671 #endif 672 673 splx(s); 674 } 675 676 /* 677 * Drain off all datagram fragments. 678 */ 679 void 680 frag6_drain(void) 681 { 682 if (frag6_doing_reass) 683 return; 684 while (ip6q.ip6q_next != &ip6q) { 685 ip6stat.ip6s_fragdropped++; 686 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 687 frag6_freef(ip6q.ip6q_next); 688 } 689 } 690