FreeBSD/Linux Kernel Cross Reference
sys/netinet6/frag6.c
1 /* $FreeBSD: releng/6.3/sys/netinet6/frag6.c 170562 2007-06-11 17:04:10Z jinmei $ */
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
65 static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
66 static void frag6_deq __P((struct ip6asfrag *));
67 static void frag6_insque __P((struct ip6q *, struct ip6q *));
68 static void frag6_remque __P((struct ip6q *));
69 static void frag6_freef __P((struct ip6q *));
70
71 static struct mtx ip6qlock;
72 /*
73 * These fields all protected by ip6qlock.
74 */
75 static u_int frag6_nfragpackets;
76 static u_int frag6_nfrags;
77 static 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
85 static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header");
86
87 /*
88 * Initialise reassembly queue and fragment identifier.
89 */
90 static void
91 frag6_change(void *tag)
92 {
93
94 ip6_maxfragpackets = nmbclusters / 4;
95 ip6_maxfrags = nmbclusters / 4;
96 }
97
98 void
99 frag6_init()
100 {
101
102 ip6_maxfragpackets = nmbclusters / 4;
103 ip6_maxfrags = nmbclusters / 4;
104 EVENTHANDLER_REGISTER(nmbclusters_change,
105 frag6_change, NULL, EVENTHANDLER_PRI_ANY);
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 */
144 int
145 frag6_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_ttl = IPV6_FRAGTTL;
262 q6->ip6q_src = ip6->ip6_src;
263 q6->ip6q_dst = ip6->ip6_dst;
264 q6->ip6q_ecn =
265 (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
266 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
267
268 q6->ip6q_nfrag = 0;
269 }
270
271 /*
272 * If it's the 1st fragment, record the length of the
273 * unfragmentable part and the next header of the fragment header.
274 */
275 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
276 if (fragoff == 0) {
277 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
278 sizeof(struct ip6_frag);
279 q6->ip6q_nxt = ip6f->ip6f_nxt;
280 }
281
282 /*
283 * Check that the reassembled packet would not exceed 65535 bytes
284 * in size.
285 * If it would exceed, discard the fragment and return an ICMP error.
286 */
287 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
288 if (q6->ip6q_unfrglen >= 0) {
289 /* The 1st fragment has already arrived. */
290 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
291 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
292 offset - sizeof(struct ip6_frag) +
293 offsetof(struct ip6_frag, ip6f_offlg));
294 IP6Q_UNLOCK();
295 return (IPPROTO_DONE);
296 }
297 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
298 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
299 offset - sizeof(struct ip6_frag) +
300 offsetof(struct ip6_frag, ip6f_offlg));
301 IP6Q_UNLOCK();
302 return (IPPROTO_DONE);
303 }
304 /*
305 * If it's the first fragment, do the above check for each
306 * fragment already stored in the reassembly queue.
307 */
308 if (fragoff == 0) {
309 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
310 af6 = af6dwn) {
311 af6dwn = af6->ip6af_down;
312
313 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
314 IPV6_MAXPACKET) {
315 struct mbuf *merr = IP6_REASS_MBUF(af6);
316 struct ip6_hdr *ip6err;
317 int erroff = af6->ip6af_offset;
318
319 /* dequeue the fragment. */
320 frag6_deq(af6);
321 free(af6, M_FTABLE);
322
323 /* adjust pointer. */
324 ip6err = mtod(merr, struct ip6_hdr *);
325
326 /*
327 * Restore source and destination addresses
328 * in the erroneous IPv6 header.
329 */
330 ip6err->ip6_src = q6->ip6q_src;
331 ip6err->ip6_dst = q6->ip6q_dst;
332
333 icmp6_error(merr, ICMP6_PARAM_PROB,
334 ICMP6_PARAMPROB_HEADER,
335 erroff - sizeof(struct ip6_frag) +
336 offsetof(struct ip6_frag, ip6f_offlg));
337 }
338 }
339 }
340
341 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
342 M_NOWAIT);
343 if (ip6af == NULL)
344 goto dropfrag;
345 bzero(ip6af, sizeof(*ip6af));
346 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
347 ip6af->ip6af_off = fragoff;
348 ip6af->ip6af_frglen = frgpartlen;
349 ip6af->ip6af_offset = offset;
350 IP6_REASS_MBUF(ip6af) = m;
351
352 if (first_frag) {
353 af6 = (struct ip6asfrag *)q6;
354 goto insert;
355 }
356
357 /*
358 * Handle ECN by comparing this segment with the first one;
359 * if CE is set, do not lose CE.
360 * drop if CE and not-ECT are mixed for the same packet.
361 */
362 ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
363 ecn0 = q6->ip6q_ecn;
364 if (ecn == IPTOS_ECN_CE) {
365 if (ecn0 == IPTOS_ECN_NOTECT) {
366 free(ip6af, M_FTABLE);
367 goto dropfrag;
368 }
369 if (ecn0 != IPTOS_ECN_CE)
370 q6->ip6q_ecn = IPTOS_ECN_CE;
371 }
372 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) {
373 free(ip6af, M_FTABLE);
374 goto dropfrag;
375 }
376
377 /*
378 * Find a segment which begins after this one does.
379 */
380 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
381 af6 = af6->ip6af_down)
382 if (af6->ip6af_off > ip6af->ip6af_off)
383 break;
384
385 #if 0
386 /*
387 * If there is a preceding segment, it may provide some of
388 * our data already. If so, drop the data from the incoming
389 * segment. If it provides all of our data, drop us.
390 */
391 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
392 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
393 - ip6af->ip6af_off;
394 if (i > 0) {
395 if (i >= ip6af->ip6af_frglen)
396 goto dropfrag;
397 m_adj(IP6_REASS_MBUF(ip6af), i);
398 ip6af->ip6af_off += i;
399 ip6af->ip6af_frglen -= i;
400 }
401 }
402
403 /*
404 * While we overlap succeeding segments trim them or,
405 * if they are completely covered, dequeue them.
406 */
407 while (af6 != (struct ip6asfrag *)q6 &&
408 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
409 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
410 if (i < af6->ip6af_frglen) {
411 af6->ip6af_frglen -= i;
412 af6->ip6af_off += i;
413 m_adj(IP6_REASS_MBUF(af6), i);
414 break;
415 }
416 af6 = af6->ip6af_down;
417 m_freem(IP6_REASS_MBUF(af6->ip6af_up));
418 frag6_deq(af6->ip6af_up);
419 }
420 #else
421 /*
422 * If the incoming framgent overlaps some existing fragments in
423 * the reassembly queue, drop it, since it is dangerous to override
424 * existing fragments from a security point of view.
425 * We don't know which fragment is the bad guy - here we trust
426 * fragment that came in earlier, with no real reason.
427 *
428 * Note: due to changes after disabling this part, mbuf passed to
429 * m_adj() below now does not meet the requirement.
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
458 insert:
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 if (q6->ip6q_ecn == IPTOS_ECN_CE)
513 ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20);
514 nxt = q6->ip6q_nxt;
515 #ifdef notyet
516 *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
517 #endif
518
519 /* Delete frag6 header */
520 if (m->m_len >= offset + sizeof(struct ip6_frag)) {
521 /* This is the only possible case with !PULLDOWN_TEST */
522 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
523 offset);
524 m->m_data += sizeof(struct ip6_frag);
525 m->m_len -= sizeof(struct ip6_frag);
526 } else {
527 /* this comes with no copy if the boundary is on cluster */
528 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
529 frag6_remque(q6);
530 frag6_nfrags -= q6->ip6q_nfrag;
531 free(q6, M_FTABLE);
532 frag6_nfragpackets--;
533 goto dropfrag;
534 }
535 m_adj(t, sizeof(struct ip6_frag));
536 m_cat(m, t);
537 }
538
539 /*
540 * Store NXT to the original.
541 */
542 {
543 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
544 *prvnxtp = nxt;
545 }
546
547 frag6_remque(q6);
548 frag6_nfrags -= q6->ip6q_nfrag;
549 free(q6, M_FTABLE);
550 frag6_nfragpackets--;
551
552 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
553 int plen = 0;
554 for (t = m; t; t = t->m_next)
555 plen += t->m_len;
556 m->m_pkthdr.len = plen;
557 }
558
559 ip6stat.ip6s_reassembled++;
560 in6_ifstat_inc(dstifp, ifs6_reass_ok);
561
562 /*
563 * Tell launch routine the next header
564 */
565
566 *mp = m;
567 *offp = offset;
568
569 IP6Q_UNLOCK();
570 return nxt;
571
572 dropfrag:
573 IP6Q_UNLOCK();
574 in6_ifstat_inc(dstifp, ifs6_reass_fail);
575 ip6stat.ip6s_fragdropped++;
576 m_freem(m);
577 return IPPROTO_DONE;
578 }
579
580 /*
581 * Free a fragment reassembly header and all
582 * associated datagrams.
583 */
584 void
585 frag6_freef(q6)
586 struct ip6q *q6;
587 {
588 struct ip6asfrag *af6, *down6;
589
590 IP6Q_LOCK_ASSERT();
591
592 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
593 af6 = down6) {
594 struct mbuf *m = IP6_REASS_MBUF(af6);
595
596 down6 = af6->ip6af_down;
597 frag6_deq(af6);
598
599 /*
600 * Return ICMP time exceeded error for the 1st fragment.
601 * Just free other fragments.
602 */
603 if (af6->ip6af_off == 0) {
604 struct ip6_hdr *ip6;
605
606 /* adjust pointer */
607 ip6 = mtod(m, struct ip6_hdr *);
608
609 /* restore source and destination addresses */
610 ip6->ip6_src = q6->ip6q_src;
611 ip6->ip6_dst = q6->ip6q_dst;
612
613 icmp6_error(m, ICMP6_TIME_EXCEEDED,
614 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
615 } else
616 m_freem(m);
617 free(af6, M_FTABLE);
618 }
619 frag6_remque(q6);
620 frag6_nfrags -= q6->ip6q_nfrag;
621 free(q6, M_FTABLE);
622 frag6_nfragpackets--;
623 }
624
625 /*
626 * Put an ip fragment on a reassembly chain.
627 * Like insque, but pointers in middle of structure.
628 */
629 void
630 frag6_enq(af6, up6)
631 struct ip6asfrag *af6, *up6;
632 {
633
634 IP6Q_LOCK_ASSERT();
635
636 af6->ip6af_up = up6;
637 af6->ip6af_down = up6->ip6af_down;
638 up6->ip6af_down->ip6af_up = af6;
639 up6->ip6af_down = af6;
640 }
641
642 /*
643 * To frag6_enq as remque is to insque.
644 */
645 void
646 frag6_deq(af6)
647 struct ip6asfrag *af6;
648 {
649
650 IP6Q_LOCK_ASSERT();
651
652 af6->ip6af_up->ip6af_down = af6->ip6af_down;
653 af6->ip6af_down->ip6af_up = af6->ip6af_up;
654 }
655
656 void
657 frag6_insque(new, old)
658 struct ip6q *new, *old;
659 {
660
661 IP6Q_LOCK_ASSERT();
662
663 new->ip6q_prev = old;
664 new->ip6q_next = old->ip6q_next;
665 old->ip6q_next->ip6q_prev= new;
666 old->ip6q_next = new;
667 }
668
669 void
670 frag6_remque(p6)
671 struct ip6q *p6;
672 {
673
674 IP6Q_LOCK_ASSERT();
675
676 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
677 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
678 }
679
680 /*
681 * IPv6 reassembling timer processing;
682 * if a timer expires on a reassembly
683 * queue, discard it.
684 */
685 void
686 frag6_slowtimo()
687 {
688 struct ip6q *q6;
689 int s = splnet();
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 splx(s);
733 }
734
735 /*
736 * Drain off all datagram fragments.
737 */
738 void
739 frag6_drain()
740 {
741
742 if (IP6Q_TRYLOCK() == 0)
743 return;
744 while (ip6q.ip6q_next != &ip6q) {
745 ip6stat.ip6s_fragdropped++;
746 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
747 frag6_freef(ip6q.ip6q_next);
748 }
749 IP6Q_UNLOCK();
750 }
Cache object: af189547cf567683b42af5e3af5de4d2
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