1 /* $NetBSD: frag6.c,v 1.52 2011/12/31 20:41:59 christos Exp $ */ 2 /* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun 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/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.52 2011/12/31 20:41:59 christos Exp $"); 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/malloc.h> 39 #include <sys/mbuf.h> 40 #include <sys/domain.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 #include <sys/errno.h> 45 #include <sys/time.h> 46 #include <sys/kernel.h> 47 #include <sys/syslog.h> 48 49 #include <net/if.h> 50 #include <net/route.h> 51 52 #include <netinet/in.h> 53 #include <netinet/in_var.h> 54 #include <netinet/ip6.h> 55 #include <netinet6/ip6_var.h> 56 #include <netinet6/ip6_private.h> 57 #include <netinet/icmp6.h> 58 59 #include <net/net_osdep.h> 60 61 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 62 static void frag6_deq(struct ip6asfrag *); 63 static void frag6_insque(struct ip6q *, struct ip6q *); 64 static void frag6_remque(struct ip6q *); 65 static void frag6_freef(struct ip6q *); 66 67 static int frag6_drainwanted; 68 69 u_int frag6_nfragpackets; 70 u_int frag6_nfrags; 71 struct ip6q ip6q; /* ip6 reassemble queue */ 72 73 static kmutex_t frag6_lock; 74 75 /* 76 * Initialise reassembly queue and fragment identifier. 77 */ 78 void 79 frag6_init(void) 80 { 81 82 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 83 mutex_init(&frag6_lock, MUTEX_DEFAULT, IPL_NET); 84 } 85 86 /* 87 * In RFC2460, fragment and reassembly rule do not agree with each other, 88 * in terms of next header field handling in fragment header. 89 * While the sender will use the same value for all of the fragmented packets, 90 * receiver is suggested not to check the consistency. 91 * 92 * fragment rule (p20): 93 * (2) A Fragment header containing: 94 * The Next Header value that identifies the first header of 95 * the Fragmentable Part of the original packet. 96 * -> next header field is same for all fragments 97 * 98 * reassembly rule (p21): 99 * The Next Header field of the last header of the Unfragmentable 100 * Part is obtained from the Next Header field of the first 101 * fragment's Fragment header. 102 * -> should grab it from the first fragment only 103 * 104 * The following note also contradicts with fragment rule - noone is going to 105 * send different fragment with different next header field. 106 * 107 * additional note (p22): 108 * The Next Header values in the Fragment headers of different 109 * fragments of the same original packet may differ. Only the value 110 * from the Offset zero fragment packet is used for reassembly. 111 * -> should grab it from the first fragment only 112 * 113 * There is no explicit reason given in the RFC. Historical reason maybe? 114 */ 115 /* 116 * Fragment input 117 */ 118 static int 119 frag6_in(struct mbuf **mp, int *offp) 120 { 121 struct rtentry *rt; 122 struct mbuf *m = *mp, *t; 123 struct ip6_hdr *ip6; 124 struct ip6_frag *ip6f; 125 struct ip6q *q6; 126 struct ip6asfrag *af6, *ip6af, *af6dwn; 127 int offset = *offp, nxt, i, next; 128 int first_frag = 0; 129 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 130 struct ifnet *dstifp; 131 static struct route ro; 132 union { 133 struct sockaddr dst; 134 struct sockaddr_in6 dst6; 135 } u; 136 137 ip6 = mtod(m, struct ip6_hdr *); 138 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 139 if (ip6f == NULL) 140 return -1; 141 142 dstifp = NULL; 143 /* find the destination interface of the packet. */ 144 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0); 145 if ((rt = rtcache_lookup(&ro, &u.dst)) != NULL && rt->rt_ifa != NULL) 146 dstifp = ((struct in6_ifaddr *)rt->rt_ifa)->ia_ifp; 147 148 /* jumbo payload can't contain a fragment header */ 149 if (ip6->ip6_plen == 0) { 150 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 151 in6_ifstat_inc(dstifp, ifs6_reass_fail); 152 return -1; 153 } 154 155 /* 156 * check whether fragment packet's fragment length is 157 * multiple of 8 octets. 158 * sizeof(struct ip6_frag) == 8 159 * sizeof(struct ip6_hdr) = 40 160 */ 161 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 162 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 163 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 164 offsetof(struct ip6_hdr, ip6_plen)); 165 in6_ifstat_inc(dstifp, ifs6_reass_fail); 166 return -1; 167 } 168 169 IP6_STATINC(IP6_STAT_FRAGMENTS); 170 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 171 172 /* offset now points to data portion */ 173 offset += sizeof(struct ip6_frag); 174 175 mutex_enter(&frag6_lock); 176 177 /* 178 * Enforce upper bound on number of fragments. 179 * If maxfrag is 0, never accept fragments. 180 * If maxfrag is -1, accept all fragments without limitation. 181 */ 182 if (ip6_maxfrags < 0) 183 ; 184 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 185 goto dropfrag; 186 187 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 188 if (ip6f->ip6f_ident == q6->ip6q_ident && 189 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 190 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 191 break; 192 193 if (q6 == &ip6q) { 194 /* 195 * the first fragment to arrive, create a reassembly queue. 196 */ 197 first_frag = 1; 198 199 /* 200 * Enforce upper bound on number of fragmented packets 201 * for which we attempt reassembly; 202 * If maxfragpackets is 0, never accept fragments. 203 * If maxfragpackets is -1, accept all fragments without 204 * limitation. 205 */ 206 if (ip6_maxfragpackets < 0) 207 ; 208 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 209 goto dropfrag; 210 frag6_nfragpackets++; 211 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 212 M_DONTWAIT); 213 if (q6 == NULL) 214 goto dropfrag; 215 memset(q6, 0, sizeof(*q6)); 216 frag6_insque(q6, &ip6q); 217 218 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 219 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 220 #ifdef notyet 221 q6->ip6q_nxtp = (u_char *)nxtp; 222 #endif 223 q6->ip6q_ident = ip6f->ip6f_ident; 224 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 225 q6->ip6q_ttl = IPV6_FRAGTTL; 226 q6->ip6q_src = ip6->ip6_src; 227 q6->ip6q_dst = ip6->ip6_dst; 228 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 229 230 q6->ip6q_nfrag = 0; 231 } 232 233 /* 234 * If it's the 1st fragment, record the length of the 235 * unfragmentable part and the next header of the fragment header. 236 */ 237 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 238 if (fragoff == 0) { 239 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 240 sizeof(struct ip6_frag); 241 q6->ip6q_nxt = ip6f->ip6f_nxt; 242 } 243 244 /* 245 * Check that the reassembled packet would not exceed 65535 bytes 246 * in size. 247 * If it would exceed, discard the fragment and return an ICMP error. 248 */ 249 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 250 if (q6->ip6q_unfrglen >= 0) { 251 /* The 1st fragment has already arrived. */ 252 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 253 mutex_exit(&frag6_lock); 254 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 255 offset - sizeof(struct ip6_frag) + 256 offsetof(struct ip6_frag, ip6f_offlg)); 257 return -1; 258 } 259 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 260 mutex_exit(&frag6_lock); 261 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 262 offset - sizeof(struct ip6_frag) + 263 offsetof(struct ip6_frag, ip6f_offlg)); 264 return -1; 265 } 266 /* 267 * If it's the first fragment, do the above check for each 268 * fragment already stored in the reassembly queue. 269 */ 270 if (fragoff == 0) { 271 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 272 af6 = af6dwn) { 273 af6dwn = af6->ip6af_down; 274 275 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 276 IPV6_MAXPACKET) { 277 struct mbuf *merr = IP6_REASS_MBUF(af6); 278 struct ip6_hdr *ip6err; 279 int erroff = af6->ip6af_offset; 280 281 /* dequeue the fragment. */ 282 frag6_deq(af6); 283 free(af6, M_FTABLE); 284 285 /* adjust pointer. */ 286 ip6err = mtod(merr, struct ip6_hdr *); 287 288 /* 289 * Restore source and destination addresses 290 * in the erroneous IPv6 header. 291 */ 292 ip6err->ip6_src = q6->ip6q_src; 293 ip6err->ip6_dst = q6->ip6q_dst; 294 295 icmp6_error(merr, ICMP6_PARAM_PROB, 296 ICMP6_PARAMPROB_HEADER, 297 erroff - sizeof(struct ip6_frag) + 298 offsetof(struct ip6_frag, ip6f_offlg)); 299 } 300 } 301 } 302 303 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 304 M_DONTWAIT); 305 if (ip6af == NULL) 306 goto dropfrag; 307 memset(ip6af, 0, sizeof(*ip6af)); 308 ip6af->ip6af_head = ip6->ip6_flow; 309 ip6af->ip6af_len = ip6->ip6_plen; 310 ip6af->ip6af_nxt = ip6->ip6_nxt; 311 ip6af->ip6af_hlim = ip6->ip6_hlim; 312 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 313 ip6af->ip6af_off = fragoff; 314 ip6af->ip6af_frglen = frgpartlen; 315 ip6af->ip6af_offset = offset; 316 IP6_REASS_MBUF(ip6af) = m; 317 318 if (first_frag) { 319 af6 = (struct ip6asfrag *)q6; 320 goto insert; 321 } 322 323 /* 324 * Find a segment which begins after this one does. 325 */ 326 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 327 af6 = af6->ip6af_down) 328 if (af6->ip6af_off > ip6af->ip6af_off) 329 break; 330 331 #if 0 332 /* 333 * If there is a preceding segment, it may provide some of 334 * our data already. If so, drop the data from the incoming 335 * segment. If it provides all of our data, drop us. 336 */ 337 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 338 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 339 - ip6af->ip6af_off; 340 if (i > 0) { 341 if (i >= ip6af->ip6af_frglen) 342 goto dropfrag; 343 m_adj(IP6_REASS_MBUF(ip6af), i); 344 ip6af->ip6af_off += i; 345 ip6af->ip6af_frglen -= i; 346 } 347 } 348 349 /* 350 * While we overlap succeeding segments trim them or, 351 * if they are completely covered, dequeue them. 352 */ 353 while (af6 != (struct ip6asfrag *)q6 && 354 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 355 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 356 if (i < af6->ip6af_frglen) { 357 af6->ip6af_frglen -= i; 358 af6->ip6af_off += i; 359 m_adj(IP6_REASS_MBUF(af6), i); 360 break; 361 } 362 af6 = af6->ip6af_down; 363 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 364 frag6_deq(af6->ip6af_up); 365 } 366 #else 367 /* 368 * If the incoming framgent overlaps some existing fragments in 369 * the reassembly queue, drop it, since it is dangerous to override 370 * existing fragments from a security point of view. 371 * We don't know which fragment is the bad guy - here we trust 372 * fragment that came in earlier, with no real reason. 373 */ 374 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 375 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 376 - ip6af->ip6af_off; 377 if (i > 0) { 378 #if 0 /* suppress the noisy log */ 379 log(LOG_ERR, "%d bytes of a fragment from %s " 380 "overlaps the previous fragment\n", 381 i, ip6_sprintf(&q6->ip6q_src)); 382 #endif 383 free(ip6af, M_FTABLE); 384 goto dropfrag; 385 } 386 } 387 if (af6 != (struct ip6asfrag *)q6) { 388 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 389 if (i > 0) { 390 #if 0 /* suppress the noisy log */ 391 log(LOG_ERR, "%d bytes of a fragment from %s " 392 "overlaps the succeeding fragment", 393 i, ip6_sprintf(&q6->ip6q_src)); 394 #endif 395 free(ip6af, M_FTABLE); 396 goto dropfrag; 397 } 398 } 399 #endif 400 401 insert: 402 403 /* 404 * Stick new segment in its place; 405 * check for complete reassembly. 406 * Move to front of packet queue, as we are 407 * the most recently active fragmented packet. 408 */ 409 frag6_enq(ip6af, af6->ip6af_up); 410 frag6_nfrags++; 411 q6->ip6q_nfrag++; 412 #if 0 /* xxx */ 413 if (q6 != ip6q.ip6q_next) { 414 frag6_remque(q6); 415 frag6_insque(q6, &ip6q); 416 } 417 #endif 418 next = 0; 419 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 420 af6 = af6->ip6af_down) { 421 if (af6->ip6af_off != next) { 422 mutex_exit(&frag6_lock); 423 return 0; 424 } 425 next += af6->ip6af_frglen; 426 } 427 if (af6->ip6af_up->ip6af_mff) { 428 mutex_exit(&frag6_lock); 429 return 0; 430 } 431 432 /* 433 * Reassembly is complete; concatenate fragments. 434 */ 435 ip6af = q6->ip6q_down; 436 t = m = IP6_REASS_MBUF(ip6af); 437 af6 = ip6af->ip6af_down; 438 frag6_deq(ip6af); 439 while (af6 != (struct ip6asfrag *)q6) { 440 af6dwn = af6->ip6af_down; 441 frag6_deq(af6); 442 while (t->m_next) 443 t = t->m_next; 444 t->m_next = IP6_REASS_MBUF(af6); 445 m_adj(t->m_next, af6->ip6af_offset); 446 free(af6, M_FTABLE); 447 af6 = af6dwn; 448 } 449 450 /* adjust offset to point where the original next header starts */ 451 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 452 free(ip6af, M_FTABLE); 453 ip6 = mtod(m, struct ip6_hdr *); 454 ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr)); 455 ip6->ip6_src = q6->ip6q_src; 456 ip6->ip6_dst = q6->ip6q_dst; 457 nxt = q6->ip6q_nxt; 458 #ifdef notyet 459 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 460 #endif 461 462 /* 463 * Delete frag6 header with as a few cost as possible. 464 */ 465 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 466 memmove((char *)ip6 + sizeof(struct ip6_frag), ip6, offset); 467 m->m_data += sizeof(struct ip6_frag); 468 m->m_len -= sizeof(struct ip6_frag); 469 } else { 470 /* this comes with no copy if the boundary is on cluster */ 471 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 472 frag6_remque(q6); 473 frag6_nfrags -= q6->ip6q_nfrag; 474 free(q6, M_FTABLE); 475 frag6_nfragpackets--; 476 goto dropfrag; 477 } 478 m_adj(t, sizeof(struct ip6_frag)); 479 m_cat(m, t); 480 } 481 482 /* 483 * Store NXT to the original. 484 */ 485 { 486 u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 487 *prvnxtp = nxt; 488 } 489 490 frag6_remque(q6); 491 frag6_nfrags -= q6->ip6q_nfrag; 492 free(q6, M_FTABLE); 493 frag6_nfragpackets--; 494 495 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 496 int plen = 0; 497 for (t = m; t; t = t->m_next) 498 plen += t->m_len; 499 m->m_pkthdr.len = plen; 500 } 501 502 IP6_STATINC(IP6_STAT_REASSEMBLED); 503 in6_ifstat_inc(dstifp, ifs6_reass_ok); 504 505 /* 506 * Tell launch routine the next header 507 */ 508 509 *mp = m; 510 *offp = offset; 511 512 mutex_exit(&frag6_lock); 513 return nxt; 514 515 dropfrag: 516 mutex_exit(&frag6_lock); 517 in6_ifstat_inc(dstifp, ifs6_reass_fail); 518 IP6_STATINC(IP6_STAT_FRAGDROPPED); 519 m_freem(m); 520 return -1; 521 } 522 523 int 524 frag6_input(struct mbuf **mp, int *offp, int proto) 525 { 526 int ret = frag6_in(mp, offp); 527 528 if (ret > 0) { 529 return ret; 530 } 531 return IPPROTO_DONE; 532 } 533 534 int 535 ip6_reass_packet(struct mbuf **mp, int offset) 536 { 537 int ret = frag6_in(mp, &offset); 538 539 if (ret <= 0) { 540 *mp = NULL; 541 } 542 return ret < 0 ? ret : 0; 543 } 544 545 /* 546 * Free a fragment reassembly header and all 547 * associated datagrams. 548 */ 549 void 550 frag6_freef(struct ip6q *q6) 551 { 552 struct ip6asfrag *af6, *down6; 553 554 KASSERT(mutex_owned(&frag6_lock)); 555 556 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 557 af6 = down6) { 558 struct mbuf *m = IP6_REASS_MBUF(af6); 559 560 down6 = af6->ip6af_down; 561 frag6_deq(af6); 562 563 /* 564 * Return ICMP time exceeded error for the 1st fragment. 565 * Just free other fragments. 566 */ 567 if (af6->ip6af_off == 0) { 568 struct ip6_hdr *ip6; 569 570 /* adjust pointer */ 571 ip6 = mtod(m, struct ip6_hdr *); 572 573 /* restoure source and destination addresses */ 574 ip6->ip6_src = q6->ip6q_src; 575 ip6->ip6_dst = q6->ip6q_dst; 576 577 icmp6_error(m, ICMP6_TIME_EXCEEDED, 578 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 579 } else 580 m_freem(m); 581 free(af6, M_FTABLE); 582 } 583 frag6_remque(q6); 584 frag6_nfrags -= q6->ip6q_nfrag; 585 free(q6, M_FTABLE); 586 frag6_nfragpackets--; 587 } 588 589 /* 590 * Put an ip fragment on a reassembly chain. 591 * Like insque, but pointers in middle of structure. 592 */ 593 void 594 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 595 { 596 597 KASSERT(mutex_owned(&frag6_lock)); 598 599 af6->ip6af_up = up6; 600 af6->ip6af_down = up6->ip6af_down; 601 up6->ip6af_down->ip6af_up = af6; 602 up6->ip6af_down = af6; 603 } 604 605 /* 606 * To frag6_enq as remque is to insque. 607 */ 608 void 609 frag6_deq(struct ip6asfrag *af6) 610 { 611 612 KASSERT(mutex_owned(&frag6_lock)); 613 614 af6->ip6af_up->ip6af_down = af6->ip6af_down; 615 af6->ip6af_down->ip6af_up = af6->ip6af_up; 616 } 617 618 void 619 frag6_insque(struct ip6q *new, struct ip6q *old) 620 { 621 622 KASSERT(mutex_owned(&frag6_lock)); 623 624 new->ip6q_prev = old; 625 new->ip6q_next = old->ip6q_next; 626 old->ip6q_next->ip6q_prev= new; 627 old->ip6q_next = new; 628 } 629 630 void 631 frag6_remque(struct ip6q *p6) 632 { 633 634 KASSERT(mutex_owned(&frag6_lock)); 635 636 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 637 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 638 } 639 640 void 641 frag6_fasttimo(void) 642 { 643 mutex_enter(softnet_lock); 644 KERNEL_LOCK(1, NULL); 645 646 if (frag6_drainwanted) { 647 frag6_drain(); 648 frag6_drainwanted = 0; 649 } 650 651 KERNEL_UNLOCK_ONE(NULL); 652 mutex_exit(softnet_lock); 653 } 654 655 /* 656 * IPv6 reassembling timer processing; 657 * if a timer expires on a reassembly 658 * queue, discard it. 659 */ 660 void 661 frag6_slowtimo(void) 662 { 663 struct ip6q *q6; 664 665 mutex_enter(softnet_lock); 666 KERNEL_LOCK(1, NULL); 667 668 mutex_enter(&frag6_lock); 669 q6 = ip6q.ip6q_next; 670 if (q6) 671 while (q6 != &ip6q) { 672 --q6->ip6q_ttl; 673 q6 = q6->ip6q_next; 674 if (q6->ip6q_prev->ip6q_ttl == 0) { 675 IP6_STATINC(IP6_STAT_FRAGTIMEOUT); 676 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 677 frag6_freef(q6->ip6q_prev); 678 } 679 } 680 /* 681 * If we are over the maximum number of fragments 682 * (due to the limit being lowered), drain off 683 * enough to get down to the new limit. 684 */ 685 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 686 ip6q.ip6q_prev) { 687 IP6_STATINC(IP6_STAT_FRAGOVERFLOW); 688 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 689 frag6_freef(ip6q.ip6q_prev); 690 } 691 mutex_exit(&frag6_lock); 692 693 KERNEL_UNLOCK_ONE(NULL); 694 mutex_exit(softnet_lock); 695 696 #if 0 697 /* 698 * Routing changes might produce a better route than we last used; 699 * make sure we notice eventually, even if forwarding only for one 700 * destination and the cache is never replaced. 701 */ 702 rtcache_free(&ip6_forward_rt); 703 rtcache_free(&ipsrcchk_rt); 704 #endif 705 706 } 707 708 void 709 frag6_drainstub(void) 710 { 711 frag6_drainwanted = 1; 712 } 713 714 /* 715 * Drain off all datagram fragments. 716 */ 717 void 718 frag6_drain(void) 719 { 720 721 if (mutex_tryenter(&frag6_lock)) { 722 while (ip6q.ip6q_next != &ip6q) { 723 IP6_STATINC(IP6_STAT_FRAGDROPPED); 724 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 725 frag6_freef(ip6q.ip6q_next); 726 } 727 mutex_exit(&frag6_lock); 728 } 729 } 730