frag6.c revision 121355
1139749Simp/* $FreeBSD: head/sys/netinet6/frag6.c 121355 2003-10-22 19:03:49Z ume $ */ 273161Sjulian/* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $ */ 373161Sjulian 473161Sjulian/* 573161Sjulian * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 673161Sjulian * All rights reserved. 773161Sjulian * 873161Sjulian * Redistribution and use in source and binary forms, with or without 973161Sjulian * modification, are permitted provided that the following conditions 1073161Sjulian * are met: 1173161Sjulian * 1. Redistributions of source code must retain the above copyright 1273161Sjulian * notice, this list of conditions and the following disclaimer. 1373161Sjulian * 2. Redistributions in binary form must reproduce the above copyright 1473161Sjulian * notice, this list of conditions and the following disclaimer in the 1573161Sjulian * documentation and/or other materials provided with the distribution. 1673161Sjulian * 3. Neither the name of the project nor the names of its contributors 1773161Sjulian * may be used to endorse or promote products derived from this software 1873161Sjulian * without specific prior written permission. 1973161Sjulian * 2073161Sjulian * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 2173161Sjulian * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2273161Sjulian * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2373161Sjulian * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 2473161Sjulian * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2573161Sjulian * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2673161Sjulian * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2773161Sjulian * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2873161Sjulian * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2973161Sjulian * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3073161Sjulian * SUCH DAMAGE. 31119418Sobrien */ 32119418Sobrien 33119418Sobrien#include "opt_random_ip_id.h" 3473161Sjulian 3590995Sjulian#include <sys/param.h> 3690995Sjulian#include <sys/systm.h> 3773161Sjulian#include <sys/malloc.h> 3890995Sjulian#include <sys/mbuf.h> 3973161Sjulian#include <sys/domain.h> 40111899Sdas#include <sys/protosw.h> 41111899Sdas#include <sys/socket.h> 4273161Sjulian#include <sys/errno.h> 4373161Sjulian#include <sys/time.h> 4473161Sjulian#include <sys/kernel.h> 4573161Sjulian#include <sys/syslog.h> 4673161Sjulian 4773161Sjulian#include <net/if.h> 4873161Sjulian#include <net/route.h> 4973161Sjulian 50129879Sphk#include <netinet/in.h> 51131579Sphk#include <netinet/in_var.h> 5273161Sjulian#include <netinet/ip6.h> 5373161Sjulian#include <netinet6/ip6_var.h> 54129968Sphk#include <netinet/icmp6.h> 5573161Sjulian 5673161Sjulian#include <net/net_osdep.h> 5773161Sjulian 5890995Sjulian/* 5990995Sjulian * Define it to get a correct behavior on per-interface statistics. 60130585Sphk * You will need to perform an extra routing table lookup, per fragment, 61131579Sphk * to do it. This may, or may not be, a performance hit. 6273161Sjulian */ 6390995Sjulian#define IN6_IFSTAT_STRICT 6490995Sjulian 6573161Sjulianstatic void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 6673161Sjulianstatic void frag6_deq __P((struct ip6asfrag *)); 67126080Sphkstatic void frag6_insque __P((struct ip6q *, struct ip6q *)); 68111815Sphkstatic void frag6_remque __P((struct ip6q *)); 69111815Sphkstatic void frag6_freef __P((struct ip6q *)); 70126080Sphk 71126080Sphkstatic struct mtx ip6qlock; 7273161Sjulian/* 7373161Sjulian * These fields all protected by ip6qlock. 7490995Sjulian */ 7590995Sjulianstatic u_int frag6_nfragpackets; 7690995Sjulianstatic u_int frag6_nfrags; 77126077Sphkstatic struct ip6q ip6q; /* ip6 reassemble queue */ 7873161Sjulian 7973161Sjulian#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF); 80131579Sphk#define IP6Q_LOCK() mtx_lock(&ip6qlock) 81131579Sphk#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock) 82131579Sphk#define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED) 83129968Sphk#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock) 84129968Sphk 8573161Sjulianstatic MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header"); 8673161Sjulian 8773161Sjulian/* 88126077Sphk * Initialise reassembly queue and fragment identifier. 89126077Sphk */ 90126077Sphkvoid 91126077Sphkfrag6_init() 9273161Sjulian{ 9373161Sjulian 94126077Sphk ip6_maxfragpackets = nmbclusters / 4; 95126077Sphk ip6_maxfrags = nmbclusters / 4; 96126077Sphk 9773161Sjulian IP6Q_LOCK_INIT(); 98130585Sphk 99126077Sphk#ifndef RANDOM_IP_ID 100126077Sphk ip6_id = arc4random(); 101126077Sphk#endif 102130585Sphk ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 103126077Sphk} 104130640Sphk 105126077Sphk/* 106126077Sphk * In RFC2460, fragment and reassembly rule do not agree with each other, 107126077Sphk * in terms of next header field handling in fragment header. 108126077Sphk * While the sender will use the same value for all of the fragmented packets, 109126077Sphk * receiver is suggested not to check the consistency. 110126077Sphk * 111126077Sphk * fragment rule (p20): 112126077Sphk * (2) A Fragment header containing: 113126077Sphk * The Next Header value that identifies the first header of 114126077Sphk * the Fragmentable Part of the original packet. 115126077Sphk * -> next header field is same for all fragments 116126077Sphk * 117126077Sphk * reassembly rule (p21): 118126077Sphk * The Next Header field of the last header of the Unfragmentable 119126077Sphk * Part is obtained from the Next Header field of the first 120126077Sphk * fragment's Fragment header. 121126077Sphk * -> should grab it from the first fragment only 122126077Sphk * 123126077Sphk * The following note also contradicts with fragment rule - noone is going to 124126077Sphk * send different fragment with different next header field. 125126077Sphk * 126126077Sphk * additional note (p22): 127126077Sphk * The Next Header values in the Fragment headers of different 128126077Sphk * fragments of the same original packet may differ. Only the value 129126077Sphk * from the Offset zero fragment packet is used for reassembly. 130126077Sphk * -> should grab it from the first fragment only 131126077Sphk * 132126077Sphk * There is no explicit reason given in the RFC. Historical reason maybe? 133126077Sphk */ 134126077Sphk/* 135126077Sphk * Fragment input 136126077Sphk */ 137126077Sphkint 138126077Sphkfrag6_input(mp, offp, proto) 139126077Sphk struct mbuf **mp; 140126077Sphk int *offp, proto; 141126077Sphk{ 142126077Sphk struct mbuf *m = *mp, *t; 143126077Sphk struct ip6_hdr *ip6; 144129968Sphk struct ip6_frag *ip6f; 145129968Sphk struct ip6q *q6; 146129968Sphk struct ip6asfrag *af6, *ip6af, *af6dwn; 147129968Sphk int offset = *offp, nxt, i, next; 148129968Sphk int first_frag = 0; 14973161Sjulian int fragoff, frgpartlen; /* must be larger than u_int16_t */ 150129968Sphk struct ifnet *dstifp; 151129968Sphk#ifdef IN6_IFSTAT_STRICT 152129968Sphk static struct route_in6 ro; 153129968Sphk struct sockaddr_in6 *dst; 154129968Sphk#endif 155131579Sphk 156129968Sphk ip6 = mtod(m, struct ip6_hdr *); 157131579Sphk#ifndef PULLDOWN_TEST 158130077Sphk IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE); 159129968Sphk ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset); 160129968Sphk#else 161129968Sphk IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 162131579Sphk if (ip6f == NULL) 163130077Sphk return (IPPROTO_DONE); 164129968Sphk#endif 165129968Sphk 166129968Sphk dstifp = NULL; 167129968Sphk#ifdef IN6_IFSTAT_STRICT 168129968Sphk /* find the destination interface of the packet. */ 169129968Sphk dst = (struct sockaddr_in6 *)&ro.ro_dst; 170129968Sphk if (ro.ro_rt 171129968Sphk && ((ro.ro_rt->rt_flags & RTF_UP) == 0 172129968Sphk || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 173130077Sphk RTFREE(ro.ro_rt); 174129968Sphk ro.ro_rt = (struct rtentry *)0; 175129968Sphk } 176129968Sphk if (ro.ro_rt == NULL) { 177129968Sphk bzero(dst, sizeof(*dst)); 17873161Sjulian dst->sin6_family = AF_INET6; 17973161Sjulian dst->sin6_len = sizeof(struct sockaddr_in6); 18073161Sjulian dst->sin6_addr = ip6->ip6_dst; 18173161Sjulian } 18273161Sjulian rtalloc((struct route *)&ro); 183130585Sphk if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 18473161Sjulian dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 185130585Sphk#else 18673161Sjulian /* we are violating the spec, this is not the destination interface */ 18773161Sjulian if ((m->m_flags & M_PKTHDR) != 0) 188126077Sphk dstifp = m->m_pkthdr.rcvif; 18973161Sjulian#endif 190126077Sphk 191126077Sphk /* jumbo payload can't contain a fragment header */ 19273161Sjulian if (ip6->ip6_plen == 0) { 193126077Sphk icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 194126077Sphk in6_ifstat_inc(dstifp, ifs6_reass_fail); 195129968Sphk return IPPROTO_DONE; 19673161Sjulian } 197126077Sphk 198126077Sphk /* 199126077Sphk * check whether fragment packet's fragment length is 200129968Sphk * multiple of 8 octets. 201129968Sphk * sizeof(struct ip6_frag) == 8 202129968Sphk * sizeof(struct ip6_hdr) = 40 203129968Sphk */ 204131579Sphk if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 205129968Sphk (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 206129968Sphk icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 207129968Sphk offsetof(struct ip6_hdr, ip6_plen)); 208129968Sphk in6_ifstat_inc(dstifp, ifs6_reass_fail); 209129968Sphk return IPPROTO_DONE; 210129968Sphk } 211129968Sphk 212131579Sphk ip6stat.ip6s_fragments++; 213129968Sphk in6_ifstat_inc(dstifp, ifs6_reass_reqd); 214129968Sphk 215129968Sphk /* offset now points to data portion */ 216129968Sphk offset += sizeof(struct ip6_frag); 217129968Sphk 218129968Sphk IP6Q_LOCK(); 219129968Sphk 220129968Sphk /* 221129968Sphk * Enforce upper bound on number of fragments. 222129968Sphk * If maxfrag is 0, never accept fragments. 223129968Sphk * If maxfrag is -1, accept all fragments without limitation. 224129968Sphk */ 22573161Sjulian if (ip6_maxfrags < 0) 22673161Sjulian ; 22790995Sjulian else if (frag6_nfrags >= (u_int)ip6_maxfrags) 22890995Sjulian goto dropfrag; 22990995Sjulian 23073161Sjulian for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 231130585Sphk if (ip6f->ip6f_ident == q6->ip6q_ident && 23273161Sjulian IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 233129968Sphk IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 23473161Sjulian break; 23573161Sjulian 236129968Sphk if (q6 == &ip6q) { 23773161Sjulian /* 238126077Sphk * the first fragment to arrive, create a reassembly queue. 239126077Sphk */ 240126077Sphk first_frag = 1; 241129968Sphk 242129968Sphk /* 24373161Sjulian * Enforce upper bound on number of fragmented packets 244129968Sphk * for which we attempt reassembly; 245129968Sphk * If maxfragpackets is 0, never accept fragments. 246129968Sphk * If maxfragpackets is -1, accept all fragments without 24790995Sjulian * limitation. 24873161Sjulian */ 249136680Sphk if (ip6_maxfragpackets < 0) 250129968Sphk ; 25193593Sjhb else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 25273161Sjulian goto dropfrag; 25373161Sjulian frag6_nfragpackets++; 25473161Sjulian q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 255130077Sphk M_DONTWAIT); 25673161Sjulian if (q6 == NULL) 25773161Sjulian goto dropfrag; 25873161Sjulian bzero(q6, sizeof(*q6)); 259129968Sphk 260131579Sphk frag6_insque(q6, &ip6q); 261131579Sphk 262131579Sphk /* ip6q_nxt will be filled afterwards, from 1st fragment */ 263131579Sphk q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 264131579Sphk#ifdef notyet 265131579Sphk q6->ip6q_nxtp = (u_char *)nxtp; 266131579Sphk#endif 267131579Sphk q6->ip6q_ident = ip6f->ip6f_ident; 268131579Sphk q6->ip6q_arrive = 0; /* Is it used anywhere? */ 269131579Sphk q6->ip6q_ttl = IPV6_FRAGTTL; 270131579Sphk q6->ip6q_src = ip6->ip6_src; 271131579Sphk q6->ip6q_dst = ip6->ip6_dst; 272131579Sphk q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 273131579Sphk 274131579Sphk q6->ip6q_nfrag = 0; 275131579Sphk } 276131579Sphk 277131579Sphk /* 278131579Sphk * If it's the 1st fragment, record the length of the 279131579Sphk * unfragmentable part and the next header of the fragment header. 280131579Sphk */ 281131579Sphk fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 282131579Sphk if (fragoff == 0) { 283131579Sphk q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 284131579Sphk sizeof(struct ip6_frag); 285131579Sphk q6->ip6q_nxt = ip6f->ip6f_nxt; 286131579Sphk } 287130585Sphk 28873161Sjulian /* 28973161Sjulian * Check that the reassembled packet would not exceed 65535 bytes 290132226Sphk * in size. 29173161Sjulian * If it would exceed, discard the fragment and return an ICMP error. 29273161Sjulian */ 29373161Sjulian frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 29490995Sjulian if (q6->ip6q_unfrglen >= 0) { 29573161Sjulian /* The 1st fragment has already arrived. */ 296129968Sphk if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 29773161Sjulian icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 298129968Sphk offset - sizeof(struct ip6_frag) + 299129968Sphk offsetof(struct ip6_frag, ip6f_offlg)); 30073161Sjulian IP6Q_UNLOCK(); 30173161Sjulian return (IPPROTO_DONE); 30273161Sjulian } 303129968Sphk } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 30473161Sjulian icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 305129968Sphk offset - sizeof(struct ip6_frag) + 30673161Sjulian offsetof(struct ip6_frag, ip6f_offlg)); 307129968Sphk IP6Q_UNLOCK(); 308129968Sphk return (IPPROTO_DONE); 30973161Sjulian } 31073161Sjulian /* 31190995Sjulian * If it's the first fragment, do the above check for each 31290995Sjulian * fragment already stored in the reassembly queue. 31390995Sjulian */ 31490995Sjulian if (fragoff == 0) { 31590995Sjulian for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 31690995Sjulian af6 = af6dwn) { 317126077Sphk af6dwn = af6->ip6af_down; 318126077Sphk 31990995Sjulian if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 32073161Sjulian IPV6_MAXPACKET) { 32190995Sjulian struct mbuf *merr = IP6_REASS_MBUF(af6); 322126077Sphk struct ip6_hdr *ip6err; 323126845Sphk int erroff = af6->ip6af_offset; 324126077Sphk 325126077Sphk /* dequeue the fragment. */ 326126077Sphk frag6_deq(af6); 32790995Sjulian free(af6, M_FTABLE); 32873161Sjulian 32990995Sjulian /* adjust pointer. */ 33090995Sjulian ip6err = mtod(merr, struct ip6_hdr *); 33190995Sjulian 332126077Sphk /* 333126077Sphk * Restore source and destination addresses 334126077Sphk * in the erroneous IPv6 header. 335126077Sphk */ 336126077Sphk ip6err->ip6_src = q6->ip6q_src; 337126077Sphk ip6err->ip6_dst = q6->ip6q_dst; 338126077Sphk 33990995Sjulian icmp6_error(merr, ICMP6_PARAM_PROB, 34090995Sjulian ICMP6_PARAMPROB_HEADER, 34190995Sjulian erroff - sizeof(struct ip6_frag) + 34290995Sjulian offsetof(struct ip6_frag, ip6f_offlg)); 34390995Sjulian } 34490995Sjulian } 34573161Sjulian } 34690995Sjulian 347 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 348 M_DONTWAIT); 349 if (ip6af == NULL) 350 goto dropfrag; 351 bzero(ip6af, sizeof(*ip6af)); 352 ip6af->ip6af_head = ip6->ip6_flow; 353 ip6af->ip6af_len = ip6->ip6_plen; 354 ip6af->ip6af_nxt = ip6->ip6_nxt; 355 ip6af->ip6af_hlim = ip6->ip6_hlim; 356 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 357 ip6af->ip6af_off = fragoff; 358 ip6af->ip6af_frglen = frgpartlen; 359 ip6af->ip6af_offset = offset; 360 IP6_REASS_MBUF(ip6af) = m; 361 362 if (first_frag) { 363 af6 = (struct ip6asfrag *)q6; 364 goto insert; 365 } 366 367 /* 368 * Find a segment which begins after this one does. 369 */ 370 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 371 af6 = af6->ip6af_down) 372 if (af6->ip6af_off > ip6af->ip6af_off) 373 break; 374 375#if 0 376 /* 377 * If there is a preceding segment, it may provide some of 378 * our data already. If so, drop the data from the incoming 379 * segment. If it provides all of our data, drop us. 380 */ 381 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 382 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 383 - ip6af->ip6af_off; 384 if (i > 0) { 385 if (i >= ip6af->ip6af_frglen) 386 goto dropfrag; 387 m_adj(IP6_REASS_MBUF(ip6af), i); 388 ip6af->ip6af_off += i; 389 ip6af->ip6af_frglen -= i; 390 } 391 } 392 393 /* 394 * While we overlap succeeding segments trim them or, 395 * if they are completely covered, dequeue them. 396 */ 397 while (af6 != (struct ip6asfrag *)q6 && 398 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 399 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 400 if (i < af6->ip6af_frglen) { 401 af6->ip6af_frglen -= i; 402 af6->ip6af_off += i; 403 m_adj(IP6_REASS_MBUF(af6), i); 404 break; 405 } 406 af6 = af6->ip6af_down; 407 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 408 frag6_deq(af6->ip6af_up); 409 } 410#else 411 /* 412 * If the incoming framgent overlaps some existing fragments in 413 * the reassembly queue, drop it, since it is dangerous to override 414 * existing fragments from a security point of view. 415 * We don't know which fragment is the bad guy - here we trust 416 * fragment that came in earlier, with no real reason. 417 */ 418 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 419 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 420 - ip6af->ip6af_off; 421 if (i > 0) { 422#if 0 /* suppress the noisy log */ 423 log(LOG_ERR, "%d bytes of a fragment from %s " 424 "overlaps the previous fragment\n", 425 i, ip6_sprintf(&q6->ip6q_src)); 426#endif 427 free(ip6af, M_FTABLE); 428 goto dropfrag; 429 } 430 } 431 if (af6 != (struct ip6asfrag *)q6) { 432 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 433 if (i > 0) { 434#if 0 /* suppress the noisy log */ 435 log(LOG_ERR, "%d bytes of a fragment from %s " 436 "overlaps the succeeding fragment", 437 i, ip6_sprintf(&q6->ip6q_src)); 438#endif 439 free(ip6af, M_FTABLE); 440 goto dropfrag; 441 } 442 } 443#endif 444 445insert: 446 447 /* 448 * Stick new segment in its place; 449 * check for complete reassembly. 450 * Move to front of packet queue, as we are 451 * the most recently active fragmented packet. 452 */ 453 frag6_enq(ip6af, af6->ip6af_up); 454 frag6_nfrags++; 455 q6->ip6q_nfrag++; 456#if 0 /* xxx */ 457 if (q6 != ip6q.ip6q_next) { 458 frag6_remque(q6); 459 frag6_insque(q6, &ip6q); 460 } 461#endif 462 next = 0; 463 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 464 af6 = af6->ip6af_down) { 465 if (af6->ip6af_off != next) { 466 IP6Q_UNLOCK(); 467 return IPPROTO_DONE; 468 } 469 next += af6->ip6af_frglen; 470 } 471 if (af6->ip6af_up->ip6af_mff) { 472 IP6Q_UNLOCK(); 473 return IPPROTO_DONE; 474 } 475 476 /* 477 * Reassembly is complete; concatenate fragments. 478 */ 479 ip6af = q6->ip6q_down; 480 t = m = IP6_REASS_MBUF(ip6af); 481 af6 = ip6af->ip6af_down; 482 frag6_deq(ip6af); 483 while (af6 != (struct ip6asfrag *)q6) { 484 af6dwn = af6->ip6af_down; 485 frag6_deq(af6); 486 while (t->m_next) 487 t = t->m_next; 488 t->m_next = IP6_REASS_MBUF(af6); 489 m_adj(t->m_next, af6->ip6af_offset); 490 free(af6, M_FTABLE); 491 af6 = af6dwn; 492 } 493 494 /* adjust offset to point where the original next header starts */ 495 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 496 free(ip6af, M_FTABLE); 497 ip6 = mtod(m, struct ip6_hdr *); 498 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr)); 499 ip6->ip6_src = q6->ip6q_src; 500 ip6->ip6_dst = q6->ip6q_dst; 501 nxt = q6->ip6q_nxt; 502#ifdef notyet 503 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 504#endif 505 506 /* 507 * Delete frag6 header with as a few cost as possible. 508 */ 509 if (offset < m->m_len) { 510 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 511 offset); 512 m->m_data += sizeof(struct ip6_frag); 513 m->m_len -= sizeof(struct ip6_frag); 514 } else { 515 /* this comes with no copy if the boundary is on cluster */ 516 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 517 frag6_remque(q6); 518 frag6_nfrags -= q6->ip6q_nfrag; 519 free(q6, M_FTABLE); 520 frag6_nfragpackets--; 521 goto dropfrag; 522 } 523 m_adj(t, sizeof(struct ip6_frag)); 524 m_cat(m, t); 525 } 526 527 /* 528 * Store NXT to the original. 529 */ 530 { 531 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 532 *prvnxtp = nxt; 533 } 534 535 frag6_remque(q6); 536 frag6_nfrags -= q6->ip6q_nfrag; 537 free(q6, M_FTABLE); 538 frag6_nfragpackets--; 539 540 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 541 int plen = 0; 542 for (t = m; t; t = t->m_next) 543 plen += t->m_len; 544 m->m_pkthdr.len = plen; 545 } 546 547 ip6stat.ip6s_reassembled++; 548 in6_ifstat_inc(dstifp, ifs6_reass_ok); 549 550 /* 551 * Tell launch routine the next header 552 */ 553 554 *mp = m; 555 *offp = offset; 556 557 IP6Q_UNLOCK(); 558 return nxt; 559 560 dropfrag: 561 IP6Q_UNLOCK(); 562 in6_ifstat_inc(dstifp, ifs6_reass_fail); 563 ip6stat.ip6s_fragdropped++; 564 m_freem(m); 565 return IPPROTO_DONE; 566} 567 568/* 569 * Free a fragment reassembly header and all 570 * associated datagrams. 571 */ 572void 573frag6_freef(q6) 574 struct ip6q *q6; 575{ 576 struct ip6asfrag *af6, *down6; 577 578 IP6Q_LOCK_ASSERT(); 579 580 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 581 af6 = down6) { 582 struct mbuf *m = IP6_REASS_MBUF(af6); 583 584 down6 = af6->ip6af_down; 585 frag6_deq(af6); 586 587 /* 588 * Return ICMP time exceeded error for the 1st fragment. 589 * Just free other fragments. 590 */ 591 if (af6->ip6af_off == 0) { 592 struct ip6_hdr *ip6; 593 594 /* adjust pointer */ 595 ip6 = mtod(m, struct ip6_hdr *); 596 597 /* restore source and destination addresses */ 598 ip6->ip6_src = q6->ip6q_src; 599 ip6->ip6_dst = q6->ip6q_dst; 600 601 icmp6_error(m, ICMP6_TIME_EXCEEDED, 602 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 603 } else 604 m_freem(m); 605 free(af6, M_FTABLE); 606 } 607 frag6_remque(q6); 608 frag6_nfrags -= q6->ip6q_nfrag; 609 free(q6, M_FTABLE); 610 frag6_nfragpackets--; 611} 612 613/* 614 * Put an ip fragment on a reassembly chain. 615 * Like insque, but pointers in middle of structure. 616 */ 617void 618frag6_enq(af6, up6) 619 struct ip6asfrag *af6, *up6; 620{ 621 622 IP6Q_LOCK_ASSERT(); 623 624 af6->ip6af_up = up6; 625 af6->ip6af_down = up6->ip6af_down; 626 up6->ip6af_down->ip6af_up = af6; 627 up6->ip6af_down = af6; 628} 629 630/* 631 * To frag6_enq as remque is to insque. 632 */ 633void 634frag6_deq(af6) 635 struct ip6asfrag *af6; 636{ 637 638 IP6Q_LOCK_ASSERT(); 639 640 af6->ip6af_up->ip6af_down = af6->ip6af_down; 641 af6->ip6af_down->ip6af_up = af6->ip6af_up; 642} 643 644void 645frag6_insque(new, old) 646 struct ip6q *new, *old; 647{ 648 649 IP6Q_LOCK_ASSERT(); 650 651 new->ip6q_prev = old; 652 new->ip6q_next = old->ip6q_next; 653 old->ip6q_next->ip6q_prev= new; 654 old->ip6q_next = new; 655} 656 657void 658frag6_remque(p6) 659 struct ip6q *p6; 660{ 661 662 IP6Q_LOCK_ASSERT(); 663 664 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 665 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 666} 667 668/* 669 * IPv6 reassembling timer processing; 670 * if a timer expires on a reassembly 671 * queue, discard it. 672 */ 673void 674frag6_slowtimo() 675{ 676 struct ip6q *q6; 677 int s = splnet(); 678 679 IP6Q_LOCK(); 680 q6 = ip6q.ip6q_next; 681 if (q6) 682 while (q6 != &ip6q) { 683 --q6->ip6q_ttl; 684 q6 = q6->ip6q_next; 685 if (q6->ip6q_prev->ip6q_ttl == 0) { 686 ip6stat.ip6s_fragtimeout++; 687 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 688 frag6_freef(q6->ip6q_prev); 689 } 690 } 691 /* 692 * If we are over the maximum number of fragments 693 * (due to the limit being lowered), drain off 694 * enough to get down to the new limit. 695 */ 696 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 697 ip6q.ip6q_prev) { 698 ip6stat.ip6s_fragoverflow++; 699 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 700 frag6_freef(ip6q.ip6q_prev); 701 } 702 IP6Q_UNLOCK(); 703 704#if 0 705 /* 706 * Routing changes might produce a better route than we last used; 707 * make sure we notice eventually, even if forwarding only for one 708 * destination and the cache is never replaced. 709 */ 710 if (ip6_forward_rt.ro_rt) { 711 RTFREE(ip6_forward_rt.ro_rt); 712 ip6_forward_rt.ro_rt = 0; 713 } 714 if (ipsrcchk_rt.ro_rt) { 715 RTFREE(ipsrcchk_rt.ro_rt); 716 ipsrcchk_rt.ro_rt = 0; 717 } 718#endif 719 720 splx(s); 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} 739