frag6.c revision 157927
1281SN/A/* $FreeBSD: head/sys/netinet6/frag6.c 157927 2006-04-21 09:25:40Z ps $ */ 2281SN/A/* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ */ 3281SN/A 4281SN/A/*- 5281SN/A * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6281SN/A * All rights reserved. 7281SN/A * 8281SN/A * Redistribution and use in source and binary forms, with or without 9281SN/A * modification, are permitted provided that the following conditions 10281SN/A * are met: 11281SN/A * 1. Redistributions of source code must retain the above copyright 12281SN/A * notice, this list of conditions and the following disclaimer. 13281SN/A * 2. Redistributions in binary form must reproduce the above copyright 14281SN/A * notice, this list of conditions and the following disclaimer in the 15281SN/A * documentation and/or other materials provided with the distribution. 16281SN/A * 3. Neither the name of the project nor the names of its contributors 17281SN/A * may be used to endorse or promote products derived from this software 18281SN/A * without specific prior written permission. 19281SN/A * 20281SN/A * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21281SN/A * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22281SN/A * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23281SN/A * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24281SN/A * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25281SN/A * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26281SN/A * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27281SN/A * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28281SN/A * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29281SN/A * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30281SN/A * SUCH DAMAGE. 31281SN/A */ 32281SN/A 33281SN/A#include <sys/param.h> 34281SN/A#include <sys/systm.h> 35281SN/A#include <sys/malloc.h> 36281SN/A#include <sys/mbuf.h> 37281SN/A#include <sys/domain.h> 38281SN/A#include <sys/protosw.h> 39281SN/A#include <sys/socket.h> 40281SN/A#include <sys/errno.h> 41281SN/A#include <sys/time.h> 42281SN/A#include <sys/kernel.h> 43281SN/A#include <sys/syslog.h> 44281SN/A 45281SN/A#include <net/if.h> 46281SN/A#include <net/route.h> 47281SN/A 48281SN/A#include <netinet/in.h> 49281SN/A#include <netinet/in_var.h> 50281SN/A#include <netinet/ip6.h> 51281SN/A#include <netinet6/ip6_var.h> 52281SN/A#include <netinet/icmp6.h> 531188Sjoehw#include <netinet/in_systm.h> /* for ECN definitions */ 54281SN/A#include <netinet/ip.h> /* for ECN definitions */ 55281SN/A 56281SN/A#include <net/net_osdep.h> 57281SN/A 58281SN/A/* 59281SN/A * Define it to get a correct behavior on per-interface statistics. 60281SN/A * You will need to perform an extra routing table lookup, per fragment, 61281SN/A * to do it. This may, or may not be, a performance hit. 62281SN/A */ 63281SN/A#define IN6_IFSTAT_STRICT 64281SN/A 65281SN/Astatic void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 66281SN/Astatic void frag6_deq __P((struct ip6asfrag *)); 67281SN/Astatic void frag6_insque __P((struct ip6q *, struct ip6q *)); 68281SN/Astatic void frag6_remque __P((struct ip6q *)); 69281SN/Astatic void frag6_freef __P((struct ip6q *)); 70281SN/A 71281SN/Astatic struct mtx ip6qlock; 72281SN/A/* 73281SN/A * These fields all protected by ip6qlock. 74281SN/A */ 75281SN/Astatic u_int frag6_nfragpackets; 76281SN/Astatic u_int frag6_nfrags; 77281SN/Astatic struct ip6q ip6q; /* ip6 reassemble queue */ 78281SN/A 79281SN/A#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80281SN/A#define IP6Q_LOCK() mtx_lock(&ip6qlock) 81281SN/A#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82281SN/A#define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 83605SN/A#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84281SN/A 85281SN/Astatic MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 86281SN/A 87281SN/A/* 88281SN/A * Initialise reassembly queue and fragment identifier. 89281SN/A */ 90281SN/Astatic void 91281SN/Afrag6_change(void *tag) 92281SN/A{ 93281SN/A 94281SN/A ip6_maxfragpackets = nmbclusters / 4; 95281SN/A ip6_maxfrags = nmbclusters / 4; 96281SN/A} 97281SN/A 98281SN/Avoid 99281SN/Afrag6_init() 100281SN/A{ 101281SN/A 102281SN/A ip6_maxfragpackets = nmbclusters / 4; 103281SN/A ip6_maxfrags = nmbclusters / 4; 104281SN/A EVENTHANDLER_REGISTER(nmbclusters_change, 105281SN/A frag6_change, NULL, EVENTHANDLER_PRI_ANY); 106281SN/A 107281SN/A IP6Q_LOCK_INIT(); 108405SN/A 109405SN/A ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 110281SN/A} 111281SN/A 112281SN/A/* 113281SN/A * In RFC2460, fragment and reassembly rule do not agree with each other, 114281SN/A * in terms of next header field handling in fragment header. 115281SN/A * While the sender will use the same value for all of the fragmented packets, 116281SN/A * receiver is suggested not to check the consistency. 117281SN/A * 118281SN/A * fragment rule (p20): 119281SN/A * (2) A Fragment header containing: 120281SN/A * The Next Header value that identifies the first header of 121281SN/A * the Fragmentable Part of the original packet. 122281SN/A * -> next header field is same for all fragments 123281SN/A * 124281SN/A * reassembly rule (p21): 125281SN/A * The Next Header field of the last header of the Unfragmentable 126281SN/A * Part is obtained from the Next Header field of the first 127281SN/A * fragment's Fragment header. 128281SN/A * -> should grab it from the first fragment only 129281SN/A * 130281SN/A * The following note also contradicts with fragment rule - noone is going to 131281SN/A * send different fragment with different next header field. 132281SN/A * 133281SN/A * additional note (p22): 134281SN/A * The Next Header values in the Fragment headers of different 135281SN/A * fragments of the same original packet may differ. Only the value 136281SN/A * from the Offset zero fragment packet is used for reassembly. 137281SN/A * -> should grab it from the first fragment only 138281SN/A * 139281SN/A * There is no explicit reason given in the RFC. Historical reason maybe? 140281SN/A */ 141281SN/A/* 142281SN/A * Fragment input 143281SN/A */ 144281SN/Aint 145281SN/Afrag6_input(mp, offp, proto) 146281SN/A struct mbuf **mp; 147281SN/A int *offp, proto; 148281SN/A{ 149281SN/A struct mbuf *m = *mp, *t; 150281SN/A struct ip6_hdr *ip6; 151281SN/A struct ip6_frag *ip6f; 152281SN/A struct ip6q *q6; 153281SN/A struct ip6asfrag *af6, *ip6af, *af6dwn; 154281SN/A#ifdef IN6_IFSTAT_STRICT 155281SN/A struct in6_ifaddr *ia; 156281SN/A#endif 157281SN/A int offset = *offp, nxt, i, next; 158281SN/A int first_frag = 0; 159281SN/A int fragoff, frgpartlen; /* must be larger than u_int16_t */ 160281SN/A struct ifnet *dstifp; 161281SN/A u_int8_t ecn, ecn0; 162281SN/A 163281SN/A ip6 = mtod(m, struct ip6_hdr *); 164281SN/A#ifndef PULLDOWN_TEST 165281SN/A IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 166281SN/A ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 167281SN/A#else 168281SN/A IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 169281SN/A if (ip6f == NULL) 170281SN/A return (IPPROTO_DONE); 171281SN/A#endif 172281SN/A 173281SN/A dstifp = NULL; 174405SN/A#ifdef IN6_IFSTAT_STRICT 175405SN/A /* find the destination interface of the packet. */ 176405SN/A if ((ia = ip6_getdstifaddr(m)) != NULL) 177405SN/A dstifp = ia->ia_ifp; 178405SN/A#else 179405SN/A /* we are violating the spec, this is not the destination interface */ 180405SN/A if ((m->m_flags & M_PKTHDR) != 0) 181281SN/A dstifp = m->m_pkthdr.rcvif; 182405SN/A#endif 183281SN/A 184281SN/A /* jumbo payload can't contain a fragment header */ 185281SN/A if (ip6->ip6_plen == 0) { 186281SN/A icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 1871188Sjoehw in6_ifstat_inc(dstifp, ifs6_reass_fail); 1881188Sjoehw return IPPROTO_DONE; 1891188Sjoehw } 1901188Sjoehw 1911188Sjoehw /* 1921188Sjoehw * check whether fragment packet's fragment length is 1931188Sjoehw * multiple of 8 octets. 194281SN/A * sizeof(struct ip6_frag) == 8 195281SN/A * sizeof(struct ip6_hdr) = 40 196281SN/A */ 197281SN/A if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 198281SN/A (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 199281SN/A icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 200281SN/A offsetof(struct ip6_hdr, ip6_plen)); 201281SN/A in6_ifstat_inc(dstifp, ifs6_reass_fail); 202281SN/A return IPPROTO_DONE; 203281SN/A } 204281SN/A 205281SN/A ip6stat.ip6s_fragments++; 206281SN/A in6_ifstat_inc(dstifp, ifs6_reass_reqd); 207281SN/A 208281SN/A /* offset now points to data portion */ 209281SN/A offset += sizeof(struct ip6_frag); 210281SN/A 211281SN/A IP6Q_LOCK(); 212281SN/A 213281SN/A /* 214281SN/A * Enforce upper bound on number of fragments. 215281SN/A * If maxfrag is 0, never accept fragments. 216281SN/A * If maxfrag is -1, accept all fragments without limitation. 217281SN/A */ 218281SN/A if (ip6_maxfrags < 0) 219281SN/A ; 220281SN/A else if (frag6_nfrags >= (u_int)ip6_maxfrags) 221281SN/A goto dropfrag; 222281SN/A 223281SN/A for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 224281SN/A if (ip6f->ip6f_ident == q6->ip6q_ident && 225281SN/A IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 226281SN/A IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 227281SN/A break; 228281SN/A 229281SN/A if (q6 == &ip6q) { 230281SN/A /* 231281SN/A * the first fragment to arrive, create a reassembly queue. 232281SN/A */ 233281SN/A first_frag = 1; 234281SN/A 235281SN/A /* 236281SN/A * Enforce upper bound on number of fragmented packets 237281SN/A * for which we attempt reassembly; 238281SN/A * If maxfragpackets is 0, never accept fragments. 239281SN/A * If maxfragpackets is -1, accept all fragments without 240281SN/A * limitation. 241281SN/A */ 242281SN/A if (ip6_maxfragpackets < 0) 243281SN/A ; 244281SN/A else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 245281SN/A goto dropfrag; 246281SN/A frag6_nfragpackets++; 247281SN/A q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 248281SN/A M_NOWAIT); 249281SN/A if (q6 == NULL) 250281SN/A goto dropfrag; 251281SN/A bzero(q6, sizeof(*q6)); 252281SN/A 253281SN/A frag6_insque(q6, &ip6q); 254281SN/A 255281SN/A /* ip6q_nxt will be filled afterwards, from 1st fragment */ 256281SN/A q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 257281SN/A#ifdef notyet 258281SN/A q6->ip6q_nxtp = (u_char *)nxtp; 259281SN/A#endif 260281SN/A q6->ip6q_ident = ip6f->ip6f_ident; 261281SN/A q6->ip6q_arrive = 0; /* Is it used anywhere? */ 262281SN/A q6->ip6q_ttl = IPV6_FRAGTTL; 263281SN/A q6->ip6q_src = ip6->ip6_src; 264281SN/A q6->ip6q_dst = ip6->ip6_dst; 265281SN/A q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 266281SN/A 267281SN/A q6->ip6q_nfrag = 0; 268281SN/A } 269281SN/A 270281SN/A /* 271281SN/A * If it's the 1st fragment, record the length of the 272281SN/A * unfragmentable part and the next header of the fragment header. 273281SN/A */ 274281SN/A fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 275281SN/A if (fragoff == 0) { 276281SN/A q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 277281SN/A sizeof(struct ip6_frag); 278281SN/A q6->ip6q_nxt = ip6f->ip6f_nxt; 279281SN/A } 280281SN/A 281281SN/A /* 282281SN/A * Check that the reassembled packet would not exceed 65535 bytes 283281SN/A * in size. 284281SN/A * If it would exceed, discard the fragment and return an ICMP error. 285281SN/A */ 286281SN/A frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 287281SN/A if (q6->ip6q_unfrglen >= 0) { 288281SN/A /* The 1st fragment has already arrived. */ 289281SN/A if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 290281SN/A icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 291281SN/A offset - sizeof(struct ip6_frag) + 292281SN/A offsetof(struct ip6_frag, ip6f_offlg)); 293281SN/A IP6Q_UNLOCK(); 294281SN/A return (IPPROTO_DONE); 295281SN/A } 296281SN/A } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 297281SN/A icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 298281SN/A offset - sizeof(struct ip6_frag) + 299281SN/A offsetof(struct ip6_frag, ip6f_offlg)); 300281SN/A IP6Q_UNLOCK(); 301281SN/A return (IPPROTO_DONE); 302281SN/A } 303281SN/A /* 304281SN/A * If it's the first fragment, do the above check for each 305281SN/A * fragment already stored in the reassembly queue. 306281SN/A */ 307281SN/A if (fragoff == 0) { 308281SN/A for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 309281SN/A af6 = af6dwn) { 310281SN/A af6dwn = af6->ip6af_down; 311281SN/A 312281SN/A if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 313281SN/A IPV6_MAXPACKET) { 314281SN/A struct mbuf *merr = IP6_REASS_MBUF(af6); 315281SN/A struct ip6_hdr *ip6err; 316281SN/A int erroff = af6->ip6af_offset; 317281SN/A 318281SN/A /* dequeue the fragment. */ 319281SN/A frag6_deq(af6); 320281SN/A free(af6, M_FTABLE); 321281SN/A 322281SN/A /* adjust pointer. */ 323281SN/A ip6err = mtod(merr, struct ip6_hdr *); 324281SN/A 325281SN/A /* 326281SN/A * Restore source and destination addresses 327281SN/A * in the erroneous IPv6 header. 328281SN/A */ 329281SN/A ip6err->ip6_src = q6->ip6q_src; 330281SN/A ip6err->ip6_dst = q6->ip6q_dst; 331281SN/A 332281SN/A icmp6_error(merr, ICMP6_PARAM_PROB, 333281SN/A ICMP6_PARAMPROB_HEADER, 334281SN/A erroff - sizeof(struct ip6_frag) + 335281SN/A offsetof(struct ip6_frag, ip6f_offlg)); 336281SN/A } 337281SN/A } 338281SN/A } 339281SN/A 340281SN/A ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 341761Sdfuchs M_NOWAIT); 342281SN/A if (ip6af == NULL) 343281SN/A goto dropfrag; 344281SN/A bzero(ip6af, sizeof(*ip6af)); 345281SN/A ip6af->ip6af_head = ip6->ip6_flow; 346761Sdfuchs ip6af->ip6af_len = ip6->ip6_plen; 347761Sdfuchs ip6af->ip6af_nxt = ip6->ip6_nxt; 348761Sdfuchs ip6af->ip6af_hlim = ip6->ip6_hlim; 349761Sdfuchs ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 350761Sdfuchs ip6af->ip6af_off = fragoff; 351761Sdfuchs ip6af->ip6af_frglen = frgpartlen; 352761Sdfuchs ip6af->ip6af_offset = offset; 353761Sdfuchs IP6_REASS_MBUF(ip6af) = m; 354281SN/A 355761Sdfuchs if (first_frag) { 356761Sdfuchs af6 = (struct ip6asfrag *)q6; 357761Sdfuchs goto insert; 358281SN/A } 359281SN/A 360281SN/A /* 361281SN/A * Handle ECN by comparing this segment with the first one; 362761Sdfuchs * if CE is set, do not lose CE. 363281SN/A * drop if CE and not-ECT are mixed for the same packet. 364281SN/A */ 365281SN/A ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK; 366281SN/A ecn0 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK; 367281SN/A if (ecn == IPTOS_ECN_CE) { 368761Sdfuchs if (ecn0 == IPTOS_ECN_NOTECT) { 369761Sdfuchs free(ip6af, M_FTABLE); 370761Sdfuchs goto dropfrag; 371281SN/A } 372281SN/A if (ecn0 != IPTOS_ECN_CE) 373281SN/A q6->ip6q_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20); 374281SN/A } 375281SN/A if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) { 376281SN/A free(ip6af, M_FTABLE); 377281SN/A goto dropfrag; 378281SN/A } 379761Sdfuchs 380281SN/A /* 381281SN/A * Find a segment which begins after this one does. 382281SN/A */ 383281SN/A for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 384281SN/A af6 = af6->ip6af_down) 385281SN/A if (af6->ip6af_off > ip6af->ip6af_off) 386281SN/A break; 387761Sdfuchs 388761Sdfuchs#if 0 389761Sdfuchs /* 390761Sdfuchs * If there is a preceding segment, it may provide some of 391761Sdfuchs * our data already. If so, drop the data from the incoming 392761Sdfuchs * segment. If it provides all of our data, drop us. 393761Sdfuchs */ 394761Sdfuchs if (af6->ip6af_up != (struct ip6asfrag *)q6) { 395761Sdfuchs i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 396761Sdfuchs - ip6af->ip6af_off; 397761Sdfuchs if (i > 0) { 398761Sdfuchs if (i >= ip6af->ip6af_frglen) 399761Sdfuchs goto dropfrag; 400281SN/A m_adj(IP6_REASS_MBUF(ip6af), i); 401281SN/A 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} 749