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 <sys/param.h> 34#include <sys/systm.h> 35#include <sys/malloc.h> 36#include <sys/mbuf.h> 37#include <sys/domain.h> 38#include <sys/protosw.h> 39#include <sys/socket.h> 40#include <sys/errno.h> 41#include <sys/time.h> 42#include <sys/kernel.h> 43#include <sys/syslog.h> 44 45#include <net/if.h> 46#include <net/route.h> 47 48#include <netinet/in.h> 49#include <netinet/in_var.h> 50#include <netinet/ip6.h> 51#include <netinet6/ip6_var.h> 52#include <netinet/icmp6.h> 53#include <netinet/in_systm.h> /* for ECN definitions */ 54#include <netinet/ip.h> /* for ECN definitions */ 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 71static struct mtx ip6qlock; 72/* 73 * These fields all protected by ip6qlock. 74 */ 75static u_int frag6_nfragpackets; 76static u_int frag6_nfrags; 77static struct ip6q ip6q; /* ip6 reassemble queue */ 78 79#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80#define IP6Q_LOCK() mtx_lock(&ip6qlock) 81#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82#define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 83#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84 85static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 86 87/* 88 * Initialise reassembly queue and fragment identifier. 89 */
| 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 <sys/param.h> 34#include <sys/systm.h> 35#include <sys/malloc.h> 36#include <sys/mbuf.h> 37#include <sys/domain.h> 38#include <sys/protosw.h> 39#include <sys/socket.h> 40#include <sys/errno.h> 41#include <sys/time.h> 42#include <sys/kernel.h> 43#include <sys/syslog.h> 44 45#include <net/if.h> 46#include <net/route.h> 47 48#include <netinet/in.h> 49#include <netinet/in_var.h> 50#include <netinet/ip6.h> 51#include <netinet6/ip6_var.h> 52#include <netinet/icmp6.h> 53#include <netinet/in_systm.h> /* for ECN definitions */ 54#include <netinet/ip.h> /* for ECN definitions */ 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 71static struct mtx ip6qlock; 72/* 73 * These fields all protected by ip6qlock. 74 */ 75static u_int frag6_nfragpackets; 76static u_int frag6_nfrags; 77static struct ip6q ip6q; /* ip6 reassemble queue */ 78 79#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80#define IP6Q_LOCK() mtx_lock(&ip6qlock) 81#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82#define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 83#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84 85static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 86 87/* 88 * Initialise reassembly queue and fragment identifier. 89 */
|
96 97 IP6Q_LOCK_INIT(); 98 99 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 100} 101 102/* 103 * In RFC2460, fragment and reassembly rule do not agree with each other, 104 * in terms of next header field handling in fragment header. 105 * While the sender will use the same value for all of the fragmented packets, 106 * receiver is suggested not to check the consistency. 107 * 108 * fragment rule (p20): 109 * (2) A Fragment header containing: 110 * The Next Header value that identifies the first header of 111 * the Fragmentable Part of the original packet. 112 * -> next header field is same for all fragments 113 * 114 * reassembly rule (p21): 115 * The Next Header field of the last header of the Unfragmentable 116 * Part is obtained from the Next Header field of the first 117 * fragment's Fragment header. 118 * -> should grab it from the first fragment only 119 * 120 * The following note also contradicts with fragment rule - noone is going to 121 * send different fragment with different next header field. 122 * 123 * additional note (p22): 124 * The Next Header values in the Fragment headers of different 125 * fragments of the same original packet may differ. Only the value 126 * from the Offset zero fragment packet is used for reassembly. 127 * -> should grab it from the first fragment only 128 * 129 * There is no explicit reason given in the RFC. Historical reason maybe? 130 */ 131/* 132 * Fragment input 133 */ 134int 135frag6_input(mp, offp, proto) 136 struct mbuf **mp; 137 int *offp, proto; 138{ 139 struct mbuf *m = *mp, *t; 140 struct ip6_hdr *ip6; 141 struct ip6_frag *ip6f; 142 struct ip6q *q6; 143 struct ip6asfrag *af6, *ip6af, *af6dwn; 144#ifdef IN6_IFSTAT_STRICT 145 struct in6_ifaddr *ia; 146#endif 147 int offset = *offp, nxt, i, next; 148 int first_frag = 0; 149 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 150 struct ifnet *dstifp; 151 u_int8_t ecn, ecn0; 152 153 ip6 = mtod(m, struct ip6_hdr *); 154#ifndef PULLDOWN_TEST 155 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 156 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 157#else 158 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 159 if (ip6f == NULL) 160 return (IPPROTO_DONE); 161#endif 162 163 dstifp = NULL; 164#ifdef IN6_IFSTAT_STRICT 165 /* find the destination interface of the packet. */ 166 if ((ia = ip6_getdstifaddr(m)) != NULL) 167 dstifp = ia->ia_ifp; 168#else 169 /* we are violating the spec, this is not the destination interface */ 170 if ((m->m_flags & M_PKTHDR) != 0) 171 dstifp = m->m_pkthdr.rcvif; 172#endif 173 174 /* jumbo payload can't contain a fragment header */ 175 if (ip6->ip6_plen == 0) { 176 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 177 in6_ifstat_inc(dstifp, ifs6_reass_fail); 178 return IPPROTO_DONE; 179 } 180 181 /* 182 * check whether fragment packet's fragment length is 183 * multiple of 8 octets. 184 * sizeof(struct ip6_frag) == 8 185 * sizeof(struct ip6_hdr) = 40 186 */ 187 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 188 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 189 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 190 offsetof(struct ip6_hdr, ip6_plen)); 191 in6_ifstat_inc(dstifp, ifs6_reass_fail); 192 return IPPROTO_DONE; 193 } 194 195 ip6stat.ip6s_fragments++; 196 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 197 198 /* offset now points to data portion */ 199 offset += sizeof(struct ip6_frag); 200 201 IP6Q_LOCK(); 202 203 /* 204 * Enforce upper bound on number of fragments. 205 * If maxfrag is 0, never accept fragments. 206 * If maxfrag is -1, accept all fragments without limitation. 207 */ 208 if (ip6_maxfrags < 0) 209 ; 210 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 211 goto dropfrag; 212 213 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 214 if (ip6f->ip6f_ident == q6->ip6q_ident && 215 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 216 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 217 break; 218 219 if (q6 == &ip6q) { 220 /* 221 * the first fragment to arrive, create a reassembly queue. 222 */ 223 first_frag = 1; 224 225 /* 226 * Enforce upper bound on number of fragmented packets 227 * for which we attempt reassembly; 228 * If maxfragpackets is 0, never accept fragments. 229 * If maxfragpackets is -1, accept all fragments without 230 * limitation. 231 */ 232 if (ip6_maxfragpackets < 0) 233 ; 234 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 235 goto dropfrag; 236 frag6_nfragpackets++; 237 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 238 M_NOWAIT); 239 if (q6 == NULL) 240 goto dropfrag; 241 bzero(q6, sizeof(*q6)); 242 243 frag6_insque(q6, &ip6q); 244 245 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 246 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 247#ifdef notyet 248 q6->ip6q_nxtp = (u_char *)nxtp; 249#endif 250 q6->ip6q_ident = ip6f->ip6f_ident; 251 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 252 q6->ip6q_ttl = IPV6_FRAGTTL; 253 q6->ip6q_src = ip6->ip6_src; 254 q6->ip6q_dst = ip6->ip6_dst; 255 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 256 257 q6->ip6q_nfrag = 0; 258 } 259 260 /* 261 * If it's the 1st fragment, record the length of the 262 * unfragmentable part and the next header of the fragment header. 263 */ 264 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 265 if (fragoff == 0) { 266 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 267 sizeof(struct ip6_frag); 268 q6->ip6q_nxt = ip6f->ip6f_nxt; 269 } 270 271 /* 272 * Check that the reassembled packet would not exceed 65535 bytes 273 * in size. 274 * If it would exceed, discard the fragment and return an ICMP error. 275 */ 276 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 277 if (q6->ip6q_unfrglen >= 0) { 278 /* The 1st fragment has already arrived. */ 279 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 280 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 281 offset - sizeof(struct ip6_frag) + 282 offsetof(struct ip6_frag, ip6f_offlg)); 283 IP6Q_UNLOCK(); 284 return (IPPROTO_DONE); 285 } 286 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 287 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 288 offset - sizeof(struct ip6_frag) + 289 offsetof(struct ip6_frag, ip6f_offlg)); 290 IP6Q_UNLOCK(); 291 return (IPPROTO_DONE); 292 } 293 /* 294 * If it's the first fragment, do the above check for each 295 * fragment already stored in the reassembly queue. 296 */ 297 if (fragoff == 0) { 298 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 299 af6 = af6dwn) { 300 af6dwn = af6->ip6af_down; 301 302 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 303 IPV6_MAXPACKET) { 304 struct mbuf *merr = IP6_REASS_MBUF(af6); 305 struct ip6_hdr *ip6err; 306 int erroff = af6->ip6af_offset; 307 308 /* dequeue the fragment. */ 309 frag6_deq(af6); 310 free(af6, M_FTABLE); 311 312 /* adjust pointer. */ 313 ip6err = mtod(merr, struct ip6_hdr *); 314 315 /* 316 * Restore source and destination addresses 317 * in the erroneous IPv6 header. 318 */ 319 ip6err->ip6_src = q6->ip6q_src; 320 ip6err->ip6_dst = q6->ip6q_dst; 321 322 icmp6_error(merr, ICMP6_PARAM_PROB, 323 ICMP6_PARAMPROB_HEADER, 324 erroff - sizeof(struct ip6_frag) + 325 offsetof(struct ip6_frag, ip6f_offlg)); 326 } 327 } 328 } 329 330 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 331 M_NOWAIT); 332 if (ip6af == NULL) 333 goto dropfrag; 334 bzero(ip6af, sizeof(*ip6af)); 335 ip6af->ip6af_head = ip6->ip6_flow; 336 ip6af->ip6af_len = ip6->ip6_plen; 337 ip6af->ip6af_nxt = ip6->ip6_nxt; 338 ip6af->ip6af_hlim = ip6->ip6_hlim; 339 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 340 ip6af->ip6af_off = fragoff; 341 ip6af->ip6af_frglen = frgpartlen; 342 ip6af->ip6af_offset = offset; 343 IP6_REASS_MBUF(ip6af) = m; 344 345 if (first_frag) { 346 af6 = (struct ip6asfrag *)q6; 347 goto insert; 348 } 349 350 /* 351 * Handle ECN by comparing this segment with the first one; 352 * if CE is set, do not lose CE. 353 * drop if CE and not-ECT are mixed for the same packet. 354 */ 355 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 356 ecn0 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK; 357 if (ecn == IPTOS_ECN_CE) { 358 if (ecn0 == IPTOS_ECN_NOTECT) { 359 free(ip6af, M_FTABLE); 360 goto dropfrag; 361 } 362 if (ecn0 != IPTOS_ECN_CE) 363 q6->ip6q_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20); 364 } 365 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 366 free(ip6af, M_FTABLE); 367 goto dropfrag; 368 } 369 370 /* 371 * Find a segment which begins after this one does. 372 */ 373 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 374 af6 = af6->ip6af_down) 375 if (af6->ip6af_off > ip6af->ip6af_off) 376 break; 377 378#if 0 379 /* 380 * If there is a preceding segment, it may provide some of 381 * our data already. If so, drop the data from the incoming 382 * segment. If it provides all of our data, drop us. 383 */ 384 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 385 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 386 - ip6af->ip6af_off; 387 if (i > 0) { 388 if (i >= ip6af->ip6af_frglen) 389 goto dropfrag; 390 m_adj(IP6_REASS_MBUF(ip6af), i); 391 ip6af->ip6af_off += i; 392 ip6af->ip6af_frglen -= i; 393 } 394 } 395 396 /* 397 * While we overlap succeeding segments trim them or, 398 * if they are completely covered, dequeue them. 399 */ 400 while (af6 != (struct ip6asfrag *)q6 && 401 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 402 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 403 if (i < af6->ip6af_frglen) { 404 af6->ip6af_frglen -= i; 405 af6->ip6af_off += i; 406 m_adj(IP6_REASS_MBUF(af6), i); 407 break; 408 } 409 af6 = af6->ip6af_down; 410 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 411 frag6_deq(af6->ip6af_up); 412 } 413#else 414 /* 415 * If the incoming framgent overlaps some existing fragments in 416 * the reassembly queue, drop it, since it is dangerous to override 417 * existing fragments from a security point of view. 418 * We don't know which fragment is the bad guy - here we trust 419 * fragment that came in earlier, with no real reason. 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 0 /* suppress the noisy log */ 426 log(LOG_ERR, "%d bytes of a fragment from %s " 427 "overlaps the previous fragment\n", 428 i, ip6_sprintf(&q6->ip6q_src)); 429#endif 430 free(ip6af, M_FTABLE); 431 goto dropfrag; 432 } 433 } 434 if (af6 != (struct ip6asfrag *)q6) { 435 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 436 if (i > 0) { 437#if 0 /* suppress the noisy log */ 438 log(LOG_ERR, "%d bytes of a fragment from %s " 439 "overlaps the succeeding fragment", 440 i, ip6_sprintf(&q6->ip6q_src)); 441#endif 442 free(ip6af, M_FTABLE); 443 goto dropfrag; 444 } 445 } 446#endif 447 448insert: 449 450 /* 451 * Stick new segment in its place; 452 * check for complete reassembly. 453 * Move to front of packet queue, as we are 454 * the most recently active fragmented packet. 455 */ 456 frag6_enq(ip6af, af6->ip6af_up); 457 frag6_nfrags++; 458 q6->ip6q_nfrag++; 459#if 0 /* xxx */ 460 if (q6 != ip6q.ip6q_next) { 461 frag6_remque(q6); 462 frag6_insque(q6, &ip6q); 463 } 464#endif 465 next = 0; 466 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 467 af6 = af6->ip6af_down) { 468 if (af6->ip6af_off != next) { 469 IP6Q_UNLOCK(); 470 return IPPROTO_DONE; 471 } 472 next += af6->ip6af_frglen; 473 } 474 if (af6->ip6af_up->ip6af_mff) { 475 IP6Q_UNLOCK(); 476 return IPPROTO_DONE; 477 } 478 479 /* 480 * Reassembly is complete; concatenate fragments. 481 */ 482 ip6af = q6->ip6q_down; 483 t = m = IP6_REASS_MBUF(ip6af); 484 af6 = ip6af->ip6af_down; 485 frag6_deq(ip6af); 486 while (af6 != (struct ip6asfrag *)q6) { 487 af6dwn = af6->ip6af_down; 488 frag6_deq(af6); 489 while (t->m_next) 490 t = t->m_next; 491 t->m_next = IP6_REASS_MBUF(af6); 492 m_adj(t->m_next, af6->ip6af_offset); 493 free(af6, M_FTABLE); 494 af6 = af6dwn; 495 } 496 497 /* adjust offset to point where the original next header starts */ 498 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 499 free(ip6af, M_FTABLE); 500 ip6 = mtod(m, struct ip6_hdr *); 501 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 502 ip6->ip6_src = q6->ip6q_src; 503 ip6->ip6_dst = q6->ip6q_dst; 504 nxt = q6->ip6q_nxt; 505#ifdef notyet 506 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 507#endif 508 509 /* 510 * Delete frag6 header with as a few cost as possible. 511 */ 512 if (offset < m->m_len) { 513 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 514 offset); 515 m->m_data += sizeof(struct ip6_frag); 516 m->m_len -= sizeof(struct ip6_frag); 517 } else { 518 /* this comes with no copy if the boundary is on cluster */ 519 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 520 frag6_remque(q6); 521 frag6_nfrags -= q6->ip6q_nfrag; 522 free(q6, M_FTABLE); 523 frag6_nfragpackets--; 524 goto dropfrag; 525 } 526 m_adj(t, sizeof(struct ip6_frag)); 527 m_cat(m, t); 528 } 529 530 /* 531 * Store NXT to the original. 532 */ 533 { 534 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 535 *prvnxtp = nxt; 536 } 537 538 frag6_remque(q6); 539 frag6_nfrags -= q6->ip6q_nfrag; 540 free(q6, M_FTABLE); 541 frag6_nfragpackets--; 542 543 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 544 int plen = 0; 545 for (t = m; t; t = t->m_next) 546 plen += t->m_len; 547 m->m_pkthdr.len = plen; 548 } 549 550 ip6stat.ip6s_reassembled++; 551 in6_ifstat_inc(dstifp, ifs6_reass_ok); 552 553 /* 554 * Tell launch routine the next header 555 */ 556 557 *mp = m; 558 *offp = offset; 559 560 IP6Q_UNLOCK(); 561 return nxt; 562 563 dropfrag: 564 IP6Q_UNLOCK(); 565 in6_ifstat_inc(dstifp, ifs6_reass_fail); 566 ip6stat.ip6s_fragdropped++; 567 m_freem(m); 568 return IPPROTO_DONE; 569} 570 571/* 572 * Free a fragment reassembly header and all 573 * associated datagrams. 574 */ 575void 576frag6_freef(q6) 577 struct ip6q *q6; 578{ 579 struct ip6asfrag *af6, *down6; 580 581 IP6Q_LOCK_ASSERT(); 582 583 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 584 af6 = down6) { 585 struct mbuf *m = IP6_REASS_MBUF(af6); 586 587 down6 = af6->ip6af_down; 588 frag6_deq(af6); 589 590 /* 591 * Return ICMP time exceeded error for the 1st fragment. 592 * Just free other fragments. 593 */ 594 if (af6->ip6af_off == 0) { 595 struct ip6_hdr *ip6; 596 597 /* adjust pointer */ 598 ip6 = mtod(m, struct ip6_hdr *); 599 600 /* restore source and destination addresses */ 601 ip6->ip6_src = q6->ip6q_src; 602 ip6->ip6_dst = q6->ip6q_dst; 603 604 icmp6_error(m, ICMP6_TIME_EXCEEDED, 605 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 606 } else 607 m_freem(m); 608 free(af6, M_FTABLE); 609 } 610 frag6_remque(q6); 611 frag6_nfrags -= q6->ip6q_nfrag; 612 free(q6, M_FTABLE); 613 frag6_nfragpackets--; 614} 615 616/* 617 * Put an ip fragment on a reassembly chain. 618 * Like insque, but pointers in middle of structure. 619 */ 620void 621frag6_enq(af6, up6) 622 struct ip6asfrag *af6, *up6; 623{ 624 625 IP6Q_LOCK_ASSERT(); 626 627 af6->ip6af_up = up6; 628 af6->ip6af_down = up6->ip6af_down; 629 up6->ip6af_down->ip6af_up = af6; 630 up6->ip6af_down = af6; 631} 632 633/* 634 * To frag6_enq as remque is to insque. 635 */ 636void 637frag6_deq(af6) 638 struct ip6asfrag *af6; 639{ 640 641 IP6Q_LOCK_ASSERT(); 642 643 af6->ip6af_up->ip6af_down = af6->ip6af_down; 644 af6->ip6af_down->ip6af_up = af6->ip6af_up; 645} 646 647void 648frag6_insque(new, old) 649 struct ip6q *new, *old; 650{ 651 652 IP6Q_LOCK_ASSERT(); 653 654 new->ip6q_prev = old; 655 new->ip6q_next = old->ip6q_next; 656 old->ip6q_next->ip6q_prev= new; 657 old->ip6q_next = new; 658} 659 660void 661frag6_remque(p6) 662 struct ip6q *p6; 663{ 664 665 IP6Q_LOCK_ASSERT(); 666 667 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 668 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 669} 670 671/* 672 * IPv6 reassembling timer processing; 673 * if a timer expires on a reassembly 674 * queue, discard it. 675 */ 676void 677frag6_slowtimo() 678{ 679 struct ip6q *q6; 680 681 IP6Q_LOCK(); 682 q6 = ip6q.ip6q_next; 683 if (q6) 684 while (q6 != &ip6q) { 685 --q6->ip6q_ttl; 686 q6 = q6->ip6q_next; 687 if (q6->ip6q_prev->ip6q_ttl == 0) { 688 ip6stat.ip6s_fragtimeout++; 689 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 690 frag6_freef(q6->ip6q_prev); 691 } 692 } 693 /* 694 * If we are over the maximum number of fragments 695 * (due to the limit being lowered), drain off 696 * enough to get down to the new limit. 697 */ 698 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 699 ip6q.ip6q_prev) { 700 ip6stat.ip6s_fragoverflow++; 701 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 702 frag6_freef(ip6q.ip6q_prev); 703 } 704 IP6Q_UNLOCK(); 705 706#if 0 707 /* 708 * Routing changes might produce a better route than we last used; 709 * make sure we notice eventually, even if forwarding only for one 710 * destination and the cache is never replaced. 711 */ 712 if (ip6_forward_rt.ro_rt) { 713 RTFREE(ip6_forward_rt.ro_rt); 714 ip6_forward_rt.ro_rt = 0; 715 } 716 if (ipsrcchk_rt.ro_rt) { 717 RTFREE(ipsrcchk_rt.ro_rt); 718 ipsrcchk_rt.ro_rt = 0; 719 } 720#endif 721} 722 723/* 724 * Drain off all datagram fragments. 725 */ 726void 727frag6_drain() 728{ 729 730 if (IP6Q_TRYLOCK() == 0) 731 return; 732 while (ip6q.ip6q_next != &ip6q) { 733 ip6stat.ip6s_fragdropped++; 734 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 735 frag6_freef(ip6q.ip6q_next); 736 } 737 IP6Q_UNLOCK(); 738}
| 106 107 IP6Q_LOCK_INIT(); 108 109 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 110} 111 112/* 113 * In RFC2460, fragment and reassembly rule do not agree with each other, 114 * in terms of next header field handling in fragment header. 115 * While the sender will use the same value for all of the fragmented packets, 116 * receiver is suggested not to check the consistency. 117 * 118 * fragment rule (p20): 119 * (2) A Fragment header containing: 120 * The Next Header value that identifies the first header of 121 * the Fragmentable Part of the original packet. 122 * -> next header field is same for all fragments 123 * 124 * reassembly rule (p21): 125 * The Next Header field of the last header of the Unfragmentable 126 * Part is obtained from the Next Header field of the first 127 * fragment's Fragment header. 128 * -> should grab it from the first fragment only 129 * 130 * The following note also contradicts with fragment rule - noone is going to 131 * send different fragment with different next header field. 132 * 133 * additional note (p22): 134 * The Next Header values in the Fragment headers of different 135 * fragments of the same original packet may differ. Only the value 136 * from the Offset zero fragment packet is used for reassembly. 137 * -> should grab it from the first fragment only 138 * 139 * There is no explicit reason given in the RFC. Historical reason maybe? 140 */ 141/* 142 * Fragment input 143 */ 144int 145frag6_input(mp, offp, proto) 146 struct mbuf **mp; 147 int *offp, proto; 148{ 149 struct mbuf *m = *mp, *t; 150 struct ip6_hdr *ip6; 151 struct ip6_frag *ip6f; 152 struct ip6q *q6; 153 struct ip6asfrag *af6, *ip6af, *af6dwn; 154#ifdef IN6_IFSTAT_STRICT 155 struct in6_ifaddr *ia; 156#endif 157 int offset = *offp, nxt, i, next; 158 int first_frag = 0; 159 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 160 struct ifnet *dstifp; 161 u_int8_t ecn, ecn0; 162 163 ip6 = mtod(m, struct ip6_hdr *); 164#ifndef PULLDOWN_TEST 165 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 166 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 167#else 168 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 169 if (ip6f == NULL) 170 return (IPPROTO_DONE); 171#endif 172 173 dstifp = NULL; 174#ifdef IN6_IFSTAT_STRICT 175 /* find the destination interface of the packet. */ 176 if ((ia = ip6_getdstifaddr(m)) != NULL) 177 dstifp = ia->ia_ifp; 178#else 179 /* we are violating the spec, this is not the destination interface */ 180 if ((m->m_flags & M_PKTHDR) != 0) 181 dstifp = m->m_pkthdr.rcvif; 182#endif 183 184 /* jumbo payload can't contain a fragment header */ 185 if (ip6->ip6_plen == 0) { 186 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 187 in6_ifstat_inc(dstifp, ifs6_reass_fail); 188 return IPPROTO_DONE; 189 } 190 191 /* 192 * check whether fragment packet's fragment length is 193 * multiple of 8 octets. 194 * sizeof(struct ip6_frag) == 8 195 * sizeof(struct ip6_hdr) = 40 196 */ 197 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 198 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 199 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 200 offsetof(struct ip6_hdr, ip6_plen)); 201 in6_ifstat_inc(dstifp, ifs6_reass_fail); 202 return IPPROTO_DONE; 203 } 204 205 ip6stat.ip6s_fragments++; 206 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 207 208 /* offset now points to data portion */ 209 offset += sizeof(struct ip6_frag); 210 211 IP6Q_LOCK(); 212 213 /* 214 * Enforce upper bound on number of fragments. 215 * If maxfrag is 0, never accept fragments. 216 * If maxfrag is -1, accept all fragments without limitation. 217 */ 218 if (ip6_maxfrags < 0) 219 ; 220 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 221 goto dropfrag; 222 223 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 224 if (ip6f->ip6f_ident == q6->ip6q_ident && 225 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 226 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 227 break; 228 229 if (q6 == &ip6q) { 230 /* 231 * the first fragment to arrive, create a reassembly queue. 232 */ 233 first_frag = 1; 234 235 /* 236 * Enforce upper bound on number of fragmented packets 237 * for which we attempt reassembly; 238 * If maxfragpackets is 0, never accept fragments. 239 * If maxfragpackets is -1, accept all fragments without 240 * limitation. 241 */ 242 if (ip6_maxfragpackets < 0) 243 ; 244 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 245 goto dropfrag; 246 frag6_nfragpackets++; 247 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 248 M_NOWAIT); 249 if (q6 == NULL) 250 goto dropfrag; 251 bzero(q6, sizeof(*q6)); 252 253 frag6_insque(q6, &ip6q); 254 255 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 256 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 257#ifdef notyet 258 q6->ip6q_nxtp = (u_char *)nxtp; 259#endif 260 q6->ip6q_ident = ip6f->ip6f_ident; 261 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 262 q6->ip6q_ttl = IPV6_FRAGTTL; 263 q6->ip6q_src = ip6->ip6_src; 264 q6->ip6q_dst = ip6->ip6_dst; 265 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 266 267 q6->ip6q_nfrag = 0; 268 } 269 270 /* 271 * If it's the 1st fragment, record the length of the 272 * unfragmentable part and the next header of the fragment header. 273 */ 274 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 275 if (fragoff == 0) { 276 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 277 sizeof(struct ip6_frag); 278 q6->ip6q_nxt = ip6f->ip6f_nxt; 279 } 280 281 /* 282 * Check that the reassembled packet would not exceed 65535 bytes 283 * in size. 284 * If it would exceed, discard the fragment and return an ICMP error. 285 */ 286 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 287 if (q6->ip6q_unfrglen >= 0) { 288 /* The 1st fragment has already arrived. */ 289 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 290 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 291 offset - sizeof(struct ip6_frag) + 292 offsetof(struct ip6_frag, ip6f_offlg)); 293 IP6Q_UNLOCK(); 294 return (IPPROTO_DONE); 295 } 296 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 297 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 298 offset - sizeof(struct ip6_frag) + 299 offsetof(struct ip6_frag, ip6f_offlg)); 300 IP6Q_UNLOCK(); 301 return (IPPROTO_DONE); 302 } 303 /* 304 * If it's the first fragment, do the above check for each 305 * fragment already stored in the reassembly queue. 306 */ 307 if (fragoff == 0) { 308 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 309 af6 = af6dwn) { 310 af6dwn = af6->ip6af_down; 311 312 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 313 IPV6_MAXPACKET) { 314 struct mbuf *merr = IP6_REASS_MBUF(af6); 315 struct ip6_hdr *ip6err; 316 int erroff = af6->ip6af_offset; 317 318 /* dequeue the fragment. */ 319 frag6_deq(af6); 320 free(af6, M_FTABLE); 321 322 /* adjust pointer. */ 323 ip6err = mtod(merr, struct ip6_hdr *); 324 325 /* 326 * Restore source and destination addresses 327 * in the erroneous IPv6 header. 328 */ 329 ip6err->ip6_src = q6->ip6q_src; 330 ip6err->ip6_dst = q6->ip6q_dst; 331 332 icmp6_error(merr, ICMP6_PARAM_PROB, 333 ICMP6_PARAMPROB_HEADER, 334 erroff - sizeof(struct ip6_frag) + 335 offsetof(struct ip6_frag, ip6f_offlg)); 336 } 337 } 338 } 339 340 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 341 M_NOWAIT); 342 if (ip6af == NULL) 343 goto dropfrag; 344 bzero(ip6af, sizeof(*ip6af)); 345 ip6af->ip6af_head = ip6->ip6_flow; 346 ip6af->ip6af_len = ip6->ip6_plen; 347 ip6af->ip6af_nxt = ip6->ip6_nxt; 348 ip6af->ip6af_hlim = ip6->ip6_hlim; 349 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 350 ip6af->ip6af_off = fragoff; 351 ip6af->ip6af_frglen = frgpartlen; 352 ip6af->ip6af_offset = offset; 353 IP6_REASS_MBUF(ip6af) = m; 354 355 if (first_frag) { 356 af6 = (struct ip6asfrag *)q6; 357 goto insert; 358 } 359 360 /* 361 * Handle ECN by comparing this segment with the first one; 362 * if CE is set, do not lose CE. 363 * drop if CE and not-ECT are mixed for the same packet. 364 */ 365 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 366 ecn0 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK; 367 if (ecn == IPTOS_ECN_CE) { 368 if (ecn0 == IPTOS_ECN_NOTECT) { 369 free(ip6af, M_FTABLE); 370 goto dropfrag; 371 } 372 if (ecn0 != IPTOS_ECN_CE) 373 q6->ip6q_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20); 374 } 375 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 376 free(ip6af, M_FTABLE); 377 goto dropfrag; 378 } 379 380 /* 381 * Find a segment which begins after this one does. 382 */ 383 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 384 af6 = af6->ip6af_down) 385 if (af6->ip6af_off > ip6af->ip6af_off) 386 break; 387 388#if 0 389 /* 390 * If there is a preceding segment, it may provide some of 391 * our data already. If so, drop the data from the incoming 392 * segment. If it provides all of our data, drop us. 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 (i >= ip6af->ip6af_frglen) 399 goto dropfrag; 400 m_adj(IP6_REASS_MBUF(ip6af), i); 401 ip6af->ip6af_off += i; 402 ip6af->ip6af_frglen -= i; 403 } 404 } 405 406 /* 407 * While we overlap succeeding segments trim them or, 408 * if they are completely covered, dequeue them. 409 */ 410 while (af6 != (struct ip6asfrag *)q6 && 411 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 412 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 413 if (i < af6->ip6af_frglen) { 414 af6->ip6af_frglen -= i; 415 af6->ip6af_off += i; 416 m_adj(IP6_REASS_MBUF(af6), i); 417 break; 418 } 419 af6 = af6->ip6af_down; 420 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 421 frag6_deq(af6->ip6af_up); 422 } 423#else 424 /* 425 * If the incoming framgent overlaps some existing fragments in 426 * the reassembly queue, drop it, since it is dangerous to override 427 * existing fragments from a security point of view. 428 * We don't know which fragment is the bad guy - here we trust 429 * fragment that came in earlier, with no real reason. 430 */ 431 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 432 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 433 - ip6af->ip6af_off; 434 if (i > 0) { 435#if 0 /* suppress the noisy log */ 436 log(LOG_ERR, "%d bytes of a fragment from %s " 437 "overlaps the previous fragment\n", 438 i, ip6_sprintf(&q6->ip6q_src)); 439#endif 440 free(ip6af, M_FTABLE); 441 goto dropfrag; 442 } 443 } 444 if (af6 != (struct ip6asfrag *)q6) { 445 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 446 if (i > 0) { 447#if 0 /* suppress the noisy log */ 448 log(LOG_ERR, "%d bytes of a fragment from %s " 449 "overlaps the succeeding fragment", 450 i, ip6_sprintf(&q6->ip6q_src)); 451#endif 452 free(ip6af, M_FTABLE); 453 goto dropfrag; 454 } 455 } 456#endif 457 458insert: 459 460 /* 461 * Stick new segment in its place; 462 * check for complete reassembly. 463 * Move to front of packet queue, as we are 464 * the most recently active fragmented packet. 465 */ 466 frag6_enq(ip6af, af6->ip6af_up); 467 frag6_nfrags++; 468 q6->ip6q_nfrag++; 469#if 0 /* xxx */ 470 if (q6 != ip6q.ip6q_next) { 471 frag6_remque(q6); 472 frag6_insque(q6, &ip6q); 473 } 474#endif 475 next = 0; 476 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 477 af6 = af6->ip6af_down) { 478 if (af6->ip6af_off != next) { 479 IP6Q_UNLOCK(); 480 return IPPROTO_DONE; 481 } 482 next += af6->ip6af_frglen; 483 } 484 if (af6->ip6af_up->ip6af_mff) { 485 IP6Q_UNLOCK(); 486 return IPPROTO_DONE; 487 } 488 489 /* 490 * Reassembly is complete; concatenate fragments. 491 */ 492 ip6af = q6->ip6q_down; 493 t = m = IP6_REASS_MBUF(ip6af); 494 af6 = ip6af->ip6af_down; 495 frag6_deq(ip6af); 496 while (af6 != (struct ip6asfrag *)q6) { 497 af6dwn = af6->ip6af_down; 498 frag6_deq(af6); 499 while (t->m_next) 500 t = t->m_next; 501 t->m_next = IP6_REASS_MBUF(af6); 502 m_adj(t->m_next, af6->ip6af_offset); 503 free(af6, M_FTABLE); 504 af6 = af6dwn; 505 } 506 507 /* adjust offset to point where the original next header starts */ 508 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 509 free(ip6af, M_FTABLE); 510 ip6 = mtod(m, struct ip6_hdr *); 511 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 512 ip6->ip6_src = q6->ip6q_src; 513 ip6->ip6_dst = q6->ip6q_dst; 514 nxt = q6->ip6q_nxt; 515#ifdef notyet 516 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 517#endif 518 519 /* 520 * Delete frag6 header with as a few cost as possible. 521 */ 522 if (offset < m->m_len) { 523 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 524 offset); 525 m->m_data += sizeof(struct ip6_frag); 526 m->m_len -= sizeof(struct ip6_frag); 527 } else { 528 /* this comes with no copy if the boundary is on cluster */ 529 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 530 frag6_remque(q6); 531 frag6_nfrags -= q6->ip6q_nfrag; 532 free(q6, M_FTABLE); 533 frag6_nfragpackets--; 534 goto dropfrag; 535 } 536 m_adj(t, sizeof(struct ip6_frag)); 537 m_cat(m, t); 538 } 539 540 /* 541 * Store NXT to the original. 542 */ 543 { 544 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 545 *prvnxtp = nxt; 546 } 547 548 frag6_remque(q6); 549 frag6_nfrags -= q6->ip6q_nfrag; 550 free(q6, M_FTABLE); 551 frag6_nfragpackets--; 552 553 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 554 int plen = 0; 555 for (t = m; t; t = t->m_next) 556 plen += t->m_len; 557 m->m_pkthdr.len = plen; 558 } 559 560 ip6stat.ip6s_reassembled++; 561 in6_ifstat_inc(dstifp, ifs6_reass_ok); 562 563 /* 564 * Tell launch routine the next header 565 */ 566 567 *mp = m; 568 *offp = offset; 569 570 IP6Q_UNLOCK(); 571 return nxt; 572 573 dropfrag: 574 IP6Q_UNLOCK(); 575 in6_ifstat_inc(dstifp, ifs6_reass_fail); 576 ip6stat.ip6s_fragdropped++; 577 m_freem(m); 578 return IPPROTO_DONE; 579} 580 581/* 582 * Free a fragment reassembly header and all 583 * associated datagrams. 584 */ 585void 586frag6_freef(q6) 587 struct ip6q *q6; 588{ 589 struct ip6asfrag *af6, *down6; 590 591 IP6Q_LOCK_ASSERT(); 592 593 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 594 af6 = down6) { 595 struct mbuf *m = IP6_REASS_MBUF(af6); 596 597 down6 = af6->ip6af_down; 598 frag6_deq(af6); 599 600 /* 601 * Return ICMP time exceeded error for the 1st fragment. 602 * Just free other fragments. 603 */ 604 if (af6->ip6af_off == 0) { 605 struct ip6_hdr *ip6; 606 607 /* adjust pointer */ 608 ip6 = mtod(m, struct ip6_hdr *); 609 610 /* restore source and destination addresses */ 611 ip6->ip6_src = q6->ip6q_src; 612 ip6->ip6_dst = q6->ip6q_dst; 613 614 icmp6_error(m, ICMP6_TIME_EXCEEDED, 615 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 616 } else 617 m_freem(m); 618 free(af6, M_FTABLE); 619 } 620 frag6_remque(q6); 621 frag6_nfrags -= q6->ip6q_nfrag; 622 free(q6, M_FTABLE); 623 frag6_nfragpackets--; 624} 625 626/* 627 * Put an ip fragment on a reassembly chain. 628 * Like insque, but pointers in middle of structure. 629 */ 630void 631frag6_enq(af6, up6) 632 struct ip6asfrag *af6, *up6; 633{ 634 635 IP6Q_LOCK_ASSERT(); 636 637 af6->ip6af_up = up6; 638 af6->ip6af_down = up6->ip6af_down; 639 up6->ip6af_down->ip6af_up = af6; 640 up6->ip6af_down = af6; 641} 642 643/* 644 * To frag6_enq as remque is to insque. 645 */ 646void 647frag6_deq(af6) 648 struct ip6asfrag *af6; 649{ 650 651 IP6Q_LOCK_ASSERT(); 652 653 af6->ip6af_up->ip6af_down = af6->ip6af_down; 654 af6->ip6af_down->ip6af_up = af6->ip6af_up; 655} 656 657void 658frag6_insque(new, old) 659 struct ip6q *new, *old; 660{ 661 662 IP6Q_LOCK_ASSERT(); 663 664 new->ip6q_prev = old; 665 new->ip6q_next = old->ip6q_next; 666 old->ip6q_next->ip6q_prev= new; 667 old->ip6q_next = new; 668} 669 670void 671frag6_remque(p6) 672 struct ip6q *p6; 673{ 674 675 IP6Q_LOCK_ASSERT(); 676 677 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 678 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 679} 680 681/* 682 * IPv6 reassembling timer processing; 683 * if a timer expires on a reassembly 684 * queue, discard it. 685 */ 686void 687frag6_slowtimo() 688{ 689 struct ip6q *q6; 690 691 IP6Q_LOCK(); 692 q6 = ip6q.ip6q_next; 693 if (q6) 694 while (q6 != &ip6q) { 695 --q6->ip6q_ttl; 696 q6 = q6->ip6q_next; 697 if (q6->ip6q_prev->ip6q_ttl == 0) { 698 ip6stat.ip6s_fragtimeout++; 699 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 700 frag6_freef(q6->ip6q_prev); 701 } 702 } 703 /* 704 * If we are over the maximum number of fragments 705 * (due to the limit being lowered), drain off 706 * enough to get down to the new limit. 707 */ 708 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 709 ip6q.ip6q_prev) { 710 ip6stat.ip6s_fragoverflow++; 711 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 712 frag6_freef(ip6q.ip6q_prev); 713 } 714 IP6Q_UNLOCK(); 715 716#if 0 717 /* 718 * Routing changes might produce a better route than we last used; 719 * make sure we notice eventually, even if forwarding only for one 720 * destination and the cache is never replaced. 721 */ 722 if (ip6_forward_rt.ro_rt) { 723 RTFREE(ip6_forward_rt.ro_rt); 724 ip6_forward_rt.ro_rt = 0; 725 } 726 if (ipsrcchk_rt.ro_rt) { 727 RTFREE(ipsrcchk_rt.ro_rt); 728 ipsrcchk_rt.ro_rt = 0; 729 } 730#endif 731} 732 733/* 734 * Drain off all datagram fragments. 735 */ 736void 737frag6_drain() 738{ 739 740 if (IP6Q_TRYLOCK() == 0) 741 return; 742 while (ip6q.ip6q_next != &ip6q) { 743 ip6stat.ip6s_fragdropped++; 744 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 745 frag6_freef(ip6q.ip6q_next); 746 } 747 IP6Q_UNLOCK(); 748}
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