1 /*- 2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the project nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_rss.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/domain.h> 42 #include <sys/eventhandler.h> 43 #include <sys/protosw.h> 44 #include <sys/socket.h> 45 #include <sys/errno.h> 46 #include <sys/time.h> 47 #include <sys/kernel.h> 48 #include <sys/syslog.h> 49 50 #include <net/if.h> 51 #include <net/if_var.h> 52 #include <net/netisr.h> 53 #include <net/route.h> 54 #include <net/vnet.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_var.h> 58 #include <netinet/ip6.h> 59 #include <netinet6/ip6_var.h> 60 #include <netinet/icmp6.h> 61 #include <netinet/in_systm.h> /* for ECN definitions */ 62 #include <netinet/ip.h> /* for ECN definitions */ 63 64 #include <security/mac/mac_framework.h> 65 66 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *); 67 static void frag6_deq(struct ip6asfrag *); 68 static void frag6_insque(struct ip6q *, struct ip6q *); 69 static void frag6_remque(struct ip6q *); 70 static void frag6_freef(struct ip6q *); 71 72 static struct mtx ip6qlock; 73 /* 74 * These fields all protected by ip6qlock. 75 */ 76 static VNET_DEFINE(u_int, frag6_nfragpackets); 77 static VNET_DEFINE(u_int, frag6_nfrags); 78 static VNET_DEFINE(struct ip6q, ip6q); /* ip6 reassemble queue */ 79 80 #define V_frag6_nfragpackets VNET(frag6_nfragpackets) 81 #define V_frag6_nfrags VNET(frag6_nfrags) 82 #define V_ip6q VNET(ip6q) 83 84 #define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 85 #define IP6Q_LOCK() mtx_lock(&ip6qlock) 86 #define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 87 #define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 88 #define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 89 90 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 91 92 /* 93 * Initialise reassembly queue and fragment identifier. 94 */ 95 static void 96 frag6_change(void *tag) 97 { 98 99 V_ip6_maxfragpackets = nmbclusters / 4; 100 V_ip6_maxfrags = nmbclusters / 4; 101 } 102 103 void 104 frag6_init(void) 105 { 106 107 V_ip6_maxfragpackets = nmbclusters / 4; 108 V_ip6_maxfrags = nmbclusters / 4; 109 V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q; 110 111 if (!IS_DEFAULT_VNET(curvnet)) 112 return; 113 114 EVENTHANDLER_REGISTER(nmbclusters_change, 115 frag6_change, NULL, EVENTHANDLER_PRI_ANY); 116 117 IP6Q_LOCK_INIT(); 118 } 119 120 /* 121 * In RFC2460, fragment and reassembly rule do not agree with each other, 122 * in terms of next header field handling in fragment header. 123 * While the sender will use the same value for all of the fragmented packets, 124 * receiver is suggested not to check the consistency. 125 * 126 * fragment rule (p20): 127 * (2) A Fragment header containing: 128 * The Next Header value that identifies the first header of 129 * the Fragmentable Part of the original packet. 130 * -> next header field is same for all fragments 131 * 132 * reassembly rule (p21): 133 * The Next Header field of the last header of the Unfragmentable 134 * Part is obtained from the Next Header field of the first 135 * fragment's Fragment header. 136 * -> should grab it from the first fragment only 137 * 138 * The following note also contradicts with fragment rule - no one is going to 139 * send different fragment with different next header field. 140 * 141 * additional note (p22): 142 * The Next Header values in the Fragment headers of different 143 * fragments of the same original packet may differ. Only the value 144 * from the Offset zero fragment packet is used for reassembly. 145 * -> should grab it from the first fragment only 146 * 147 * There is no explicit reason given in the RFC. Historical reason maybe? 148 */ 149 /* 150 * Fragment input 151 */ 152 int 153 frag6_input(struct mbuf **mp, int *offp, int proto) 154 { 155 struct mbuf *m = *mp, *t; 156 struct ip6_hdr *ip6; 157 struct ip6_frag *ip6f; 158 struct ip6q *q6; 159 struct ip6asfrag *af6, *ip6af, *af6dwn; 160 struct in6_ifaddr *ia; 161 int offset = *offp, nxt, i, next; 162 int first_frag = 0; 163 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 164 struct ifnet *dstifp; 165 u_int8_t ecn, ecn0; 166 #ifdef RSS 167 struct m_tag *mtag; 168 struct ip6_direct_ctx *ip6dc; 169 #endif 170 171 #if 0 172 char ip6buf[INET6_ADDRSTRLEN]; 173 #endif 174 175 ip6 = mtod(m, struct ip6_hdr *); 176 #ifndef PULLDOWN_TEST 177 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 178 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 179 #else 180 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 181 if (ip6f == NULL) 182 return (IPPROTO_DONE); 183 #endif 184 185 dstifp = NULL; 186 /* find the destination interface of the packet. */ 187 ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */); 188 if (ia != NULL) { 189 dstifp = ia->ia_ifp; 190 ifa_free(&ia->ia_ifa); 191 } 192 /* jumbo payload can't contain a fragment header */ 193 if (ip6->ip6_plen == 0) { 194 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 195 in6_ifstat_inc(dstifp, ifs6_reass_fail); 196 return IPPROTO_DONE; 197 } 198 199 /* 200 * check whether fragment packet's fragment length is 201 * multiple of 8 octets. 202 * sizeof(struct ip6_frag) == 8 203 * sizeof(struct ip6_hdr) = 40 204 */ 205 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 206 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 207 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 208 offsetof(struct ip6_hdr, ip6_plen)); 209 in6_ifstat_inc(dstifp, ifs6_reass_fail); 210 return IPPROTO_DONE; 211 } 212 213 IP6STAT_INC(ip6s_fragments); 214 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 215 216 /* offset now points to data portion */ 217 offset += sizeof(struct ip6_frag); 218 219 /* 220 * RFC 6946: Handle "atomic" fragments (offset and m bit set to 0) 221 * upfront, unrelated to any reassembly. Just skip the fragment header. 222 */ 223 if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) { 224 /* XXX-BZ we want dedicated counters for this. */ 225 IP6STAT_INC(ip6s_reassembled); 226 in6_ifstat_inc(dstifp, ifs6_reass_ok); 227 *offp = offset; 228 return (ip6f->ip6f_nxt); 229 } 230 231 IP6Q_LOCK(); 232 233 /* 234 * Enforce upper bound on number of fragments. 235 * If maxfrag is 0, never accept fragments. 236 * If maxfrag is -1, accept all fragments without limitation. 237 */ 238 if (V_ip6_maxfrags < 0) 239 ; 240 else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags) 241 goto dropfrag; 242 243 for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next) 244 if (ip6f->ip6f_ident == q6->ip6q_ident && 245 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 246 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst) 247 #ifdef MAC 248 && mac_ip6q_match(m, q6) 249 #endif 250 ) 251 break; 252 253 if (q6 == &V_ip6q) { 254 /* 255 * the first fragment to arrive, create a reassembly queue. 256 */ 257 first_frag = 1; 258 259 /* 260 * Enforce upper bound on number of fragmented packets 261 * for which we attempt reassembly; 262 * If maxfragpackets is 0, never accept fragments. 263 * If maxfragpackets is -1, accept all fragments without 264 * limitation. 265 */ 266 if (V_ip6_maxfragpackets < 0) 267 ; 268 else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets) 269 goto dropfrag; 270 V_frag6_nfragpackets++; 271 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 272 M_NOWAIT); 273 if (q6 == NULL) 274 goto dropfrag; 275 bzero(q6, sizeof(*q6)); 276 #ifdef MAC 277 if (mac_ip6q_init(q6, M_NOWAIT) != 0) { 278 free(q6, M_FTABLE); 279 goto dropfrag; 280 } 281 mac_ip6q_create(m, q6); 282 #endif 283 frag6_insque(q6, &V_ip6q); 284 285 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 286 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 287 #ifdef notyet 288 q6->ip6q_nxtp = (u_char *)nxtp; 289 #endif 290 q6->ip6q_ident = ip6f->ip6f_ident; 291 q6->ip6q_ttl = IPV6_FRAGTTL; 292 q6->ip6q_src = ip6->ip6_src; 293 q6->ip6q_dst = ip6->ip6_dst; 294 q6->ip6q_ecn = 295 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 296 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 297 298 q6->ip6q_nfrag = 0; 299 } 300 301 /* 302 * If it's the 1st fragment, record the length of the 303 * unfragmentable part and the next header of the fragment header. 304 */ 305 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 306 if (fragoff == 0) { 307 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 308 sizeof(struct ip6_frag); 309 q6->ip6q_nxt = ip6f->ip6f_nxt; 310 } 311 312 /* 313 * Check that the reassembled packet would not exceed 65535 bytes 314 * in size. 315 * If it would exceed, discard the fragment and return an ICMP error. 316 */ 317 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 318 if (q6->ip6q_unfrglen >= 0) { 319 /* The 1st fragment has already arrived. */ 320 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 321 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 322 offset - sizeof(struct ip6_frag) + 323 offsetof(struct ip6_frag, ip6f_offlg)); 324 IP6Q_UNLOCK(); 325 return (IPPROTO_DONE); 326 } 327 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 328 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 329 offset - sizeof(struct ip6_frag) + 330 offsetof(struct ip6_frag, ip6f_offlg)); 331 IP6Q_UNLOCK(); 332 return (IPPROTO_DONE); 333 } 334 /* 335 * If it's the first fragment, do the above check for each 336 * fragment already stored in the reassembly queue. 337 */ 338 if (fragoff == 0) { 339 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 340 af6 = af6dwn) { 341 af6dwn = af6->ip6af_down; 342 343 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 344 IPV6_MAXPACKET) { 345 struct mbuf *merr = IP6_REASS_MBUF(af6); 346 struct ip6_hdr *ip6err; 347 int erroff = af6->ip6af_offset; 348 349 /* dequeue the fragment. */ 350 frag6_deq(af6); 351 free(af6, M_FTABLE); 352 353 /* adjust pointer. */ 354 ip6err = mtod(merr, struct ip6_hdr *); 355 356 /* 357 * Restore source and destination addresses 358 * in the erroneous IPv6 header. 359 */ 360 ip6err->ip6_src = q6->ip6q_src; 361 ip6err->ip6_dst = q6->ip6q_dst; 362 363 icmp6_error(merr, ICMP6_PARAM_PROB, 364 ICMP6_PARAMPROB_HEADER, 365 erroff - sizeof(struct ip6_frag) + 366 offsetof(struct ip6_frag, ip6f_offlg)); 367 } 368 } 369 } 370 371 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 372 M_NOWAIT); 373 if (ip6af == NULL) 374 goto dropfrag; 375 bzero(ip6af, sizeof(*ip6af)); 376 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 377 ip6af->ip6af_off = fragoff; 378 ip6af->ip6af_frglen = frgpartlen; 379 ip6af->ip6af_offset = offset; 380 IP6_REASS_MBUF(ip6af) = m; 381 382 if (first_frag) { 383 af6 = (struct ip6asfrag *)q6; 384 goto insert; 385 } 386 387 /* 388 * Handle ECN by comparing this segment with the first one; 389 * if CE is set, do not lose CE. 390 * drop if CE and not-ECT are mixed for the same packet. 391 */ 392 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 393 ecn0 = q6->ip6q_ecn; 394 if (ecn == IPTOS_ECN_CE) { 395 if (ecn0 == IPTOS_ECN_NOTECT) { 396 free(ip6af, M_FTABLE); 397 goto dropfrag; 398 } 399 if (ecn0 != IPTOS_ECN_CE) 400 q6->ip6q_ecn = IPTOS_ECN_CE; 401 } 402 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 403 free(ip6af, M_FTABLE); 404 goto dropfrag; 405 } 406 407 /* 408 * Find a segment which begins after this one does. 409 */ 410 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 411 af6 = af6->ip6af_down) 412 if (af6->ip6af_off > ip6af->ip6af_off) 413 break; 414 415 #if 0 416 /* 417 * If there is a preceding segment, it may provide some of 418 * our data already. If so, drop the data from the incoming 419 * segment. If it provides all of our data, drop us. 420 */ 421 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 422 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 423 - ip6af->ip6af_off; 424 if (i > 0) { 425 if (i >= ip6af->ip6af_frglen) 426 goto dropfrag; 427 m_adj(IP6_REASS_MBUF(ip6af), i); 428 ip6af->ip6af_off += i; 429 ip6af->ip6af_frglen -= i; 430 } 431 } 432 433 /* 434 * While we overlap succeeding segments trim them or, 435 * if they are completely covered, dequeue them. 436 */ 437 while (af6 != (struct ip6asfrag *)q6 && 438 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 439 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 440 if (i < af6->ip6af_frglen) { 441 af6->ip6af_frglen -= i; 442 af6->ip6af_off += i; 443 m_adj(IP6_REASS_MBUF(af6), i); 444 break; 445 } 446 af6 = af6->ip6af_down; 447 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 448 frag6_deq(af6->ip6af_up); 449 } 450 #else 451 /* 452 * If the incoming framgent overlaps some existing fragments in 453 * the reassembly queue, drop it, since it is dangerous to override 454 * existing fragments from a security point of view. 455 * We don't know which fragment is the bad guy - here we trust 456 * fragment that came in earlier, with no real reason. 457 * 458 * Note: due to changes after disabling this part, mbuf passed to 459 * m_adj() below now does not meet the requirement. 460 */ 461 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 462 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 463 - ip6af->ip6af_off; 464 if (i > 0) { 465 #if 0 /* suppress the noisy log */ 466 log(LOG_ERR, "%d bytes of a fragment from %s " 467 "overlaps the previous fragment\n", 468 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 469 #endif 470 free(ip6af, M_FTABLE); 471 goto dropfrag; 472 } 473 } 474 if (af6 != (struct ip6asfrag *)q6) { 475 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 476 if (i > 0) { 477 #if 0 /* suppress the noisy log */ 478 log(LOG_ERR, "%d bytes of a fragment from %s " 479 "overlaps the succeeding fragment", 480 i, ip6_sprintf(ip6buf, &q6->ip6q_src)); 481 #endif 482 free(ip6af, M_FTABLE); 483 goto dropfrag; 484 } 485 } 486 #endif 487 488 insert: 489 #ifdef MAC 490 if (!first_frag) 491 mac_ip6q_update(m, q6); 492 #endif 493 494 /* 495 * Stick new segment in its place; 496 * check for complete reassembly. 497 * Move to front of packet queue, as we are 498 * the most recently active fragmented packet. 499 */ 500 frag6_enq(ip6af, af6->ip6af_up); 501 V_frag6_nfrags++; 502 q6->ip6q_nfrag++; 503 #if 0 /* xxx */ 504 if (q6 != V_ip6q.ip6q_next) { 505 frag6_remque(q6); 506 frag6_insque(q6, &V_ip6q); 507 } 508 #endif 509 next = 0; 510 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 511 af6 = af6->ip6af_down) { 512 if (af6->ip6af_off != next) { 513 IP6Q_UNLOCK(); 514 return IPPROTO_DONE; 515 } 516 next += af6->ip6af_frglen; 517 } 518 if (af6->ip6af_up->ip6af_mff) { 519 IP6Q_UNLOCK(); 520 return IPPROTO_DONE; 521 } 522 523 /* 524 * Reassembly is complete; concatenate fragments. 525 */ 526 ip6af = q6->ip6q_down; 527 t = m = IP6_REASS_MBUF(ip6af); 528 af6 = ip6af->ip6af_down; 529 frag6_deq(ip6af); 530 while (af6 != (struct ip6asfrag *)q6) { 531 af6dwn = af6->ip6af_down; 532 frag6_deq(af6); 533 while (t->m_next) 534 t = t->m_next; 535 m_adj(IP6_REASS_MBUF(af6), af6->ip6af_offset); 536 m_cat(t, IP6_REASS_MBUF(af6)); 537 free(af6, M_FTABLE); 538 af6 = af6dwn; 539 } 540 541 /* adjust offset to point where the original next header starts */ 542 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 543 free(ip6af, M_FTABLE); 544 ip6 = mtod(m, struct ip6_hdr *); 545 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 546 if (q6->ip6q_ecn == IPTOS_ECN_CE) 547 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20); 548 nxt = q6->ip6q_nxt; 549 #ifdef notyet 550 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 551 #endif 552 553 if (ip6_deletefraghdr(m, offset, M_NOWAIT) != 0) { 554 frag6_remque(q6); 555 V_frag6_nfrags -= q6->ip6q_nfrag; 556 #ifdef MAC 557 mac_ip6q_destroy(q6); 558 #endif 559 free(q6, M_FTABLE); 560 V_frag6_nfragpackets--; 561 562 goto dropfrag; 563 } 564 565 /* 566 * Store NXT to the original. 567 */ 568 { 569 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 570 *prvnxtp = nxt; 571 } 572 573 frag6_remque(q6); 574 V_frag6_nfrags -= q6->ip6q_nfrag; 575 #ifdef MAC 576 mac_ip6q_reassemble(q6, m); 577 mac_ip6q_destroy(q6); 578 #endif 579 free(q6, M_FTABLE); 580 V_frag6_nfragpackets--; 581 582 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 583 int plen = 0; 584 for (t = m; t; t = t->m_next) 585 plen += t->m_len; 586 m->m_pkthdr.len = plen; 587 } 588 589 #ifdef RSS 590 mtag = m_tag_alloc(MTAG_ABI_IPV6, IPV6_TAG_DIRECT, sizeof(*ip6dc), 591 M_NOWAIT); 592 if (mtag == NULL) 593 goto dropfrag; 594 595 ip6dc = (struct ip6_direct_ctx *)(mtag + 1); 596 ip6dc->ip6dc_nxt = nxt; 597 ip6dc->ip6dc_off = offset; 598 599 m_tag_prepend(m, mtag); 600 #endif 601 602 IP6Q_UNLOCK(); 603 IP6STAT_INC(ip6s_reassembled); 604 in6_ifstat_inc(dstifp, ifs6_reass_ok); 605 606 #ifdef RSS 607 /* 608 * Queue/dispatch for reprocessing. 609 */ 610 netisr_dispatch(NETISR_IPV6_DIRECT, m); 611 return IPPROTO_DONE; 612 #endif 613 614 /* 615 * Tell launch routine the next header 616 */ 617 618 *mp = m; 619 *offp = offset; 620 621 return nxt; 622 623 dropfrag: 624 IP6Q_UNLOCK(); 625 in6_ifstat_inc(dstifp, ifs6_reass_fail); 626 IP6STAT_INC(ip6s_fragdropped); 627 m_freem(m); 628 return IPPROTO_DONE; 629 } 630 631 /* 632 * Free a fragment reassembly header and all 633 * associated datagrams. 634 */ 635 void 636 frag6_freef(struct ip6q *q6) 637 { 638 struct ip6asfrag *af6, *down6; 639 640 IP6Q_LOCK_ASSERT(); 641 642 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 643 af6 = down6) { 644 struct mbuf *m = IP6_REASS_MBUF(af6); 645 646 down6 = af6->ip6af_down; 647 frag6_deq(af6); 648 649 /* 650 * Return ICMP time exceeded error for the 1st fragment. 651 * Just free other fragments. 652 */ 653 if (af6->ip6af_off == 0) { 654 struct ip6_hdr *ip6; 655 656 /* adjust pointer */ 657 ip6 = mtod(m, struct ip6_hdr *); 658 659 /* restore source and destination addresses */ 660 ip6->ip6_src = q6->ip6q_src; 661 ip6->ip6_dst = q6->ip6q_dst; 662 663 icmp6_error(m, ICMP6_TIME_EXCEEDED, 664 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 665 } else 666 m_freem(m); 667 free(af6, M_FTABLE); 668 } 669 frag6_remque(q6); 670 V_frag6_nfrags -= q6->ip6q_nfrag; 671 #ifdef MAC 672 mac_ip6q_destroy(q6); 673 #endif 674 free(q6, M_FTABLE); 675 V_frag6_nfragpackets--; 676 } 677 678 /* 679 * Put an ip fragment on a reassembly chain. 680 * Like insque, but pointers in middle of structure. 681 */ 682 void 683 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6) 684 { 685 686 IP6Q_LOCK_ASSERT(); 687 688 af6->ip6af_up = up6; 689 af6->ip6af_down = up6->ip6af_down; 690 up6->ip6af_down->ip6af_up = af6; 691 up6->ip6af_down = af6; 692 } 693 694 /* 695 * To frag6_enq as remque is to insque. 696 */ 697 void 698 frag6_deq(struct ip6asfrag *af6) 699 { 700 701 IP6Q_LOCK_ASSERT(); 702 703 af6->ip6af_up->ip6af_down = af6->ip6af_down; 704 af6->ip6af_down->ip6af_up = af6->ip6af_up; 705 } 706 707 void 708 frag6_insque(struct ip6q *new, struct ip6q *old) 709 { 710 711 IP6Q_LOCK_ASSERT(); 712 713 new->ip6q_prev = old; 714 new->ip6q_next = old->ip6q_next; 715 old->ip6q_next->ip6q_prev= new; 716 old->ip6q_next = new; 717 } 718 719 void 720 frag6_remque(struct ip6q *p6) 721 { 722 723 IP6Q_LOCK_ASSERT(); 724 725 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 726 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 727 } 728 729 /* 730 * IPv6 reassembling timer processing; 731 * if a timer expires on a reassembly 732 * queue, discard it. 733 */ 734 void 735 frag6_slowtimo(void) 736 { 737 VNET_ITERATOR_DECL(vnet_iter); 738 struct ip6q *q6; 739 740 VNET_LIST_RLOCK_NOSLEEP(); 741 IP6Q_LOCK(); 742 VNET_FOREACH(vnet_iter) { 743 CURVNET_SET(vnet_iter); 744 q6 = V_ip6q.ip6q_next; 745 if (q6) 746 while (q6 != &V_ip6q) { 747 --q6->ip6q_ttl; 748 q6 = q6->ip6q_next; 749 if (q6->ip6q_prev->ip6q_ttl == 0) { 750 IP6STAT_INC(ip6s_fragtimeout); 751 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 752 frag6_freef(q6->ip6q_prev); 753 } 754 } 755 /* 756 * If we are over the maximum number of fragments 757 * (due to the limit being lowered), drain off 758 * enough to get down to the new limit. 759 */ 760 while (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets && 761 V_ip6q.ip6q_prev) { 762 IP6STAT_INC(ip6s_fragoverflow); 763 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 764 frag6_freef(V_ip6q.ip6q_prev); 765 } 766 CURVNET_RESTORE(); 767 } 768 IP6Q_UNLOCK(); 769 VNET_LIST_RUNLOCK_NOSLEEP(); 770 } 771 772 /* 773 * Drain off all datagram fragments. 774 */ 775 void 776 frag6_drain(void) 777 { 778 VNET_ITERATOR_DECL(vnet_iter); 779 780 VNET_LIST_RLOCK_NOSLEEP(); 781 if (IP6Q_TRYLOCK() == 0) { 782 VNET_LIST_RUNLOCK_NOSLEEP(); 783 return; 784 } 785 VNET_FOREACH(vnet_iter) { 786 CURVNET_SET(vnet_iter); 787 while (V_ip6q.ip6q_next != &V_ip6q) { 788 IP6STAT_INC(ip6s_fragdropped); 789 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 790 frag6_freef(V_ip6q.ip6q_next); 791 } 792 CURVNET_RESTORE(); 793 } 794 IP6Q_UNLOCK(); 795 VNET_LIST_RUNLOCK_NOSLEEP(); 796 } 797 798 int 799 ip6_deletefraghdr(struct mbuf *m, int offset, int wait) 800 { 801 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 802 struct mbuf *t; 803 804 /* Delete frag6 header. */ 805 if (m->m_len >= offset + sizeof(struct ip6_frag)) { 806 /* This is the only possible case with !PULLDOWN_TEST. */ 807 bcopy(ip6, (char *)ip6 + sizeof(struct ip6_frag), 808 offset); 809 m->m_data += sizeof(struct ip6_frag); 810 m->m_len -= sizeof(struct ip6_frag); 811 } else { 812 /* This comes with no copy if the boundary is on cluster. */ 813 if ((t = m_split(m, offset, wait)) == NULL) 814 return (ENOMEM); 815 m_adj(t, sizeof(struct ip6_frag)); 816 m_cat(m, t); 817 } 818 819 return (0); 820 } 821