1 /* $NetBSD: frag6.c,v 1.56 2014/09/05 05:33:06 matt Exp $ */
2 /* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun 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/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.56 2014/09/05 05:33:06 matt Exp $");
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/mbuf.h>
39 #include <sys/domain.h>
40 #include <sys/protosw.h>
41 #include <sys/socket.h>
42 #include <sys/socketvar.h>
43 #include <sys/errno.h>
44 #include <sys/time.h>
45 #include <sys/kmem.h>
46 #include <sys/kernel.h>
47 #include <sys/syslog.h>
48
49 #include <net/if.h>
50 #include <net/route.h>
51
52 #include <netinet/in.h>
53 #include <netinet/in_var.h>
54 #include <netinet/ip6.h>
55 #include <netinet6/ip6_var.h>
56 #include <netinet6/ip6_private.h>
57 #include <netinet/icmp6.h>
58
59 #include <net/net_osdep.h>
60
61 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *);
62 static void frag6_deq(struct ip6asfrag *);
63 static void frag6_insque(struct ip6q *, struct ip6q *);
64 static void frag6_remque(struct ip6q *);
65 static void frag6_freef(struct ip6q *);
66
67 static int frag6_drainwanted;
68
69 u_int frag6_nfragpackets;
70 u_int frag6_nfrags;
71 struct ip6q ip6q; /* ip6 reassemble queue */
72
73 static kmutex_t frag6_lock;
74
75 /*
76 * Initialise reassembly queue and fragment identifier.
77 */
78 void
frag6_init(void)79 frag6_init(void)
80 {
81
82 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
83 mutex_init(&frag6_lock, MUTEX_DEFAULT, IPL_NET);
84 }
85
86 /*
87 * IPv6 fragment input.
88 *
89 * In RFC2460, fragment and reassembly rule do not agree with each other,
90 * in terms of next header field handling in fragment header.
91 * While the sender will use the same value for all of the fragmented packets,
92 * receiver is suggested not to check the consistency.
93 *
94 * fragment rule (p20):
95 * (2) A Fragment header containing:
96 * The Next Header value that identifies the first header of
97 * the Fragmentable Part of the original packet.
98 * -> next header field is same for all fragments
99 *
100 * reassembly rule (p21):
101 * The Next Header field of the last header of the Unfragmentable
102 * Part is obtained from the Next Header field of the first
103 * fragment's Fragment header.
104 * -> should grab it from the first fragment only
105 *
106 * The following note also contradicts with fragment rule - noone is going to
107 * send different fragment with different next header field.
108 *
109 * additional note (p22):
110 * The Next Header values in the Fragment headers of different
111 * fragments of the same original packet may differ. Only the value
112 * from the Offset zero fragment packet is used for reassembly.
113 * -> should grab it from the first fragment only
114 *
115 * There is no explicit reason given in the RFC. Historical reason maybe?
116 */
117 int
frag6_input(struct mbuf ** mp,int * offp,int proto)118 frag6_input(struct mbuf **mp, int *offp, int proto)
119 {
120 struct rtentry *rt;
121 struct mbuf *m = *mp, *t;
122 struct ip6_hdr *ip6;
123 struct ip6_frag *ip6f;
124 struct ip6q *q6;
125 struct ip6asfrag *af6, *ip6af, *af6dwn;
126 int offset = *offp, nxt, i, next;
127 int first_frag = 0;
128 int fragoff, frgpartlen; /* must be larger than u_int16_t */
129 struct ifnet *dstifp;
130 static struct route ro;
131 union {
132 struct sockaddr dst;
133 struct sockaddr_in6 dst6;
134 } u;
135
136 ip6 = mtod(m, struct ip6_hdr *);
137 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
138 if (ip6f == NULL)
139 return IPPROTO_DONE;
140
141 dstifp = NULL;
142 /* find the destination interface of the packet. */
143 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);
144 if ((rt = rtcache_lookup(&ro, &u.dst)) != NULL && rt->rt_ifa != NULL)
145 dstifp = ((struct in6_ifaddr *)rt->rt_ifa)->ia_ifp;
146
147 /* jumbo payload can't contain a fragment header */
148 if (ip6->ip6_plen == 0) {
149 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
150 in6_ifstat_inc(dstifp, ifs6_reass_fail);
151 return IPPROTO_DONE;
152 }
153
154 /*
155 * check whether fragment packet's fragment length is
156 * multiple of 8 octets.
157 * sizeof(struct ip6_frag) == 8
158 * sizeof(struct ip6_hdr) = 40
159 */
160 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
161 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
162 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
163 offsetof(struct ip6_hdr, ip6_plen));
164 in6_ifstat_inc(dstifp, ifs6_reass_fail);
165 return IPPROTO_DONE;
166 }
167
168 IP6_STATINC(IP6_STAT_FRAGMENTS);
169 in6_ifstat_inc(dstifp, ifs6_reass_reqd);
170
171 /* offset now points to data portion */
172 offset += sizeof(struct ip6_frag);
173
174 /*
175 * RFC6946: A host that receives an IPv6 packet which includes
176 * a Fragment Header with the "Fragmen Offset" equal to 0 and
177 * the "M" bit equal to 0 MUST process such packet in isolation
178 * from any other packets/fragments.
179 */
180 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
181 if (fragoff == 0 && !(ip6f->ip6f_offlg & IP6F_MORE_FRAG)) {
182 IP6_STATINC(IP6_STAT_REASSEMBLED);
183 in6_ifstat_inc(dstifp, ifs6_reass_ok);
184 *offp = offset;
185 return ip6f->ip6f_nxt;
186 }
187
188 mutex_enter(&frag6_lock);
189
190 /*
191 * Enforce upper bound on number of fragments.
192 * If maxfrag is 0, never accept fragments.
193 * If maxfrag is -1, accept all fragments without limitation.
194 */
195 if (ip6_maxfrags < 0)
196 ;
197 else if (frag6_nfrags >= (u_int)ip6_maxfrags)
198 goto dropfrag;
199
200 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
201 if (ip6f->ip6f_ident == q6->ip6q_ident &&
202 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
203 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
204 break;
205
206 if (q6 == &ip6q) {
207 /*
208 * the first fragment to arrive, create a reassembly queue.
209 */
210 first_frag = 1;
211
212 /*
213 * Enforce upper bound on number of fragmented packets
214 * for which we attempt reassembly;
215 * If maxfragpackets is 0, never accept fragments.
216 * If maxfragpackets is -1, accept all fragments without
217 * limitation.
218 */
219 if (ip6_maxfragpackets < 0)
220 ;
221 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
222 goto dropfrag;
223 frag6_nfragpackets++;
224
225 q6 = kmem_intr_zalloc(sizeof(struct ip6q), KM_NOSLEEP);
226 if (q6 == NULL) {
227 goto dropfrag;
228 }
229 frag6_insque(q6, &ip6q);
230
231 /* ip6q_nxt will be filled afterwards, from 1st fragment */
232 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
233 #ifdef notyet
234 q6->ip6q_nxtp = (u_char *)nxtp;
235 #endif
236 q6->ip6q_ident = ip6f->ip6f_ident;
237 q6->ip6q_arrive = 0; /* Is it used anywhere? */
238 q6->ip6q_ttl = IPV6_FRAGTTL;
239 q6->ip6q_src = ip6->ip6_src;
240 q6->ip6q_dst = ip6->ip6_dst;
241 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
242
243 q6->ip6q_nfrag = 0;
244 }
245
246 /*
247 * If it's the 1st fragment, record the length of the
248 * unfragmentable part and the next header of the fragment header.
249 */
250
251 if (fragoff == 0) {
252 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
253 sizeof(struct ip6_frag);
254 q6->ip6q_nxt = ip6f->ip6f_nxt;
255 }
256
257 /*
258 * Check that the reassembled packet would not exceed 65535 bytes
259 * in size.
260 * If it would exceed, discard the fragment and return an ICMP error.
261 */
262 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
263 if (q6->ip6q_unfrglen >= 0) {
264 /* The 1st fragment has already arrived. */
265 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
266 mutex_exit(&frag6_lock);
267 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
268 offset - sizeof(struct ip6_frag) +
269 offsetof(struct ip6_frag, ip6f_offlg));
270 return IPPROTO_DONE;
271 }
272 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
273 mutex_exit(&frag6_lock);
274 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
275 offset - sizeof(struct ip6_frag) +
276 offsetof(struct ip6_frag, ip6f_offlg));
277 return IPPROTO_DONE;
278 }
279 /*
280 * If it's the first fragment, do the above check for each
281 * fragment already stored in the reassembly queue.
282 */
283 if (fragoff == 0) {
284 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
285 af6 = af6dwn) {
286 af6dwn = af6->ip6af_down;
287
288 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
289 IPV6_MAXPACKET) {
290 struct mbuf *merr = IP6_REASS_MBUF(af6);
291 struct ip6_hdr *ip6err;
292 int erroff = af6->ip6af_offset;
293
294 /* dequeue the fragment. */
295 frag6_deq(af6);
296 kmem_intr_free(af6, sizeof(struct ip6asfrag));
297
298 /* adjust pointer. */
299 ip6err = mtod(merr, struct ip6_hdr *);
300
301 /*
302 * Restore source and destination addresses
303 * in the erroneous IPv6 header.
304 */
305 ip6err->ip6_src = q6->ip6q_src;
306 ip6err->ip6_dst = q6->ip6q_dst;
307
308 icmp6_error(merr, ICMP6_PARAM_PROB,
309 ICMP6_PARAMPROB_HEADER,
310 erroff - sizeof(struct ip6_frag) +
311 offsetof(struct ip6_frag, ip6f_offlg));
312 }
313 }
314 }
315
316 ip6af = kmem_intr_zalloc(sizeof(struct ip6asfrag), KM_NOSLEEP);
317 if (ip6af == NULL) {
318 goto dropfrag;
319 }
320 ip6af->ip6af_head = ip6->ip6_flow;
321 ip6af->ip6af_len = ip6->ip6_plen;
322 ip6af->ip6af_nxt = ip6->ip6_nxt;
323 ip6af->ip6af_hlim = ip6->ip6_hlim;
324 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
325 ip6af->ip6af_off = fragoff;
326 ip6af->ip6af_frglen = frgpartlen;
327 ip6af->ip6af_offset = offset;
328 IP6_REASS_MBUF(ip6af) = m;
329
330 if (first_frag) {
331 af6 = (struct ip6asfrag *)q6;
332 goto insert;
333 }
334
335 /*
336 * Find a segment which begins after this one does.
337 */
338 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
339 af6 = af6->ip6af_down)
340 if (af6->ip6af_off > ip6af->ip6af_off)
341 break;
342
343 /*
344 * If the incoming fragment overlaps some existing fragments in
345 * the reassembly queue - drop it as per RFC 5722.
346 */
347 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
348 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
349 - ip6af->ip6af_off;
350 if (i > 0) {
351 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
352 goto dropfrag;
353 }
354 }
355 if (af6 != (struct ip6asfrag *)q6) {
356 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
357 if (i > 0) {
358 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
359 goto dropfrag;
360 }
361 }
362
363 insert:
364
365 /*
366 * Stick new segment in its place;
367 * check for complete reassembly.
368 * Move to front of packet queue, as we are
369 * the most recently active fragmented packet.
370 */
371 frag6_enq(ip6af, af6->ip6af_up);
372 frag6_nfrags++;
373 q6->ip6q_nfrag++;
374 #if 0 /* xxx */
375 if (q6 != ip6q.ip6q_next) {
376 frag6_remque(q6);
377 frag6_insque(q6, &ip6q);
378 }
379 #endif
380 next = 0;
381 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
382 af6 = af6->ip6af_down) {
383 if (af6->ip6af_off != next) {
384 mutex_exit(&frag6_lock);
385 return IPPROTO_DONE;
386 }
387 next += af6->ip6af_frglen;
388 }
389 if (af6->ip6af_up->ip6af_mff) {
390 mutex_exit(&frag6_lock);
391 return IPPROTO_DONE;
392 }
393
394 /*
395 * Reassembly is complete; concatenate fragments.
396 */
397 ip6af = q6->ip6q_down;
398 t = m = IP6_REASS_MBUF(ip6af);
399 af6 = ip6af->ip6af_down;
400 frag6_deq(ip6af);
401 while (af6 != (struct ip6asfrag *)q6) {
402 af6dwn = af6->ip6af_down;
403 frag6_deq(af6);
404 while (t->m_next)
405 t = t->m_next;
406 t->m_next = IP6_REASS_MBUF(af6);
407 m_adj(t->m_next, af6->ip6af_offset);
408 kmem_intr_free(af6, sizeof(struct ip6asfrag));
409 af6 = af6dwn;
410 }
411
412 /* adjust offset to point where the original next header starts */
413 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
414 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
415 ip6 = mtod(m, struct ip6_hdr *);
416 ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr));
417 ip6->ip6_src = q6->ip6q_src;
418 ip6->ip6_dst = q6->ip6q_dst;
419 nxt = q6->ip6q_nxt;
420 #ifdef notyet
421 *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
422 #endif
423
424 /*
425 * Delete frag6 header with as a few cost as possible.
426 */
427 if (m->m_len >= offset + sizeof(struct ip6_frag)) {
428 memmove((char *)ip6 + sizeof(struct ip6_frag), ip6, offset);
429 m->m_data += sizeof(struct ip6_frag);
430 m->m_len -= sizeof(struct ip6_frag);
431 } else {
432 /* this comes with no copy if the boundary is on cluster */
433 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
434 frag6_remque(q6);
435 frag6_nfrags -= q6->ip6q_nfrag;
436 kmem_intr_free(q6, sizeof(struct ip6q));
437 frag6_nfragpackets--;
438 goto dropfrag;
439 }
440 m_adj(t, sizeof(struct ip6_frag));
441 m_cat(m, t);
442 }
443
444 /*
445 * Store NXT to the original.
446 */
447 {
448 u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
449 *prvnxtp = nxt;
450 }
451
452 frag6_remque(q6);
453 frag6_nfrags -= q6->ip6q_nfrag;
454 kmem_intr_free(q6, sizeof(struct ip6q));
455 frag6_nfragpackets--;
456
457 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
458 int plen = 0;
459 for (t = m; t; t = t->m_next)
460 plen += t->m_len;
461 m->m_pkthdr.len = plen;
462 }
463
464 IP6_STATINC(IP6_STAT_REASSEMBLED);
465 in6_ifstat_inc(dstifp, ifs6_reass_ok);
466
467 /*
468 * Tell launch routine the next header
469 */
470
471 *mp = m;
472 *offp = offset;
473
474 mutex_exit(&frag6_lock);
475 return nxt;
476
477 dropfrag:
478 mutex_exit(&frag6_lock);
479 in6_ifstat_inc(dstifp, ifs6_reass_fail);
480 IP6_STATINC(IP6_STAT_FRAGDROPPED);
481 m_freem(m);
482 return IPPROTO_DONE;
483 }
484
485 int
ip6_reass_packet(struct mbuf ** mp,int offset)486 ip6_reass_packet(struct mbuf **mp, int offset)
487 {
488
489 if (frag6_input(mp, &offset, IPPROTO_IPV6) == IPPROTO_DONE) {
490 *mp = NULL;
491 return EINVAL;
492 }
493 return 0;
494 }
495
496 /*
497 * Free a fragment reassembly header and all
498 * associated datagrams.
499 */
500 void
frag6_freef(struct ip6q * q6)501 frag6_freef(struct ip6q *q6)
502 {
503 struct ip6asfrag *af6, *down6;
504
505 KASSERT(mutex_owned(&frag6_lock));
506
507 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
508 af6 = down6) {
509 struct mbuf *m = IP6_REASS_MBUF(af6);
510
511 down6 = af6->ip6af_down;
512 frag6_deq(af6);
513
514 /*
515 * Return ICMP time exceeded error for the 1st fragment.
516 * Just free other fragments.
517 */
518 if (af6->ip6af_off == 0) {
519 struct ip6_hdr *ip6;
520
521 /* adjust pointer */
522 ip6 = mtod(m, struct ip6_hdr *);
523
524 /* restoure source and destination addresses */
525 ip6->ip6_src = q6->ip6q_src;
526 ip6->ip6_dst = q6->ip6q_dst;
527
528 icmp6_error(m, ICMP6_TIME_EXCEEDED,
529 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
530 } else {
531 m_freem(m);
532 }
533 kmem_intr_free(af6, sizeof(struct ip6asfrag));
534 }
535 frag6_remque(q6);
536 frag6_nfrags -= q6->ip6q_nfrag;
537 kmem_intr_free(q6, sizeof(struct ip6q));
538 frag6_nfragpackets--;
539 }
540
541 /*
542 * Put an ip fragment on a reassembly chain.
543 * Like insque, but pointers in middle of structure.
544 */
545 void
frag6_enq(struct ip6asfrag * af6,struct ip6asfrag * up6)546 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6)
547 {
548
549 KASSERT(mutex_owned(&frag6_lock));
550
551 af6->ip6af_up = up6;
552 af6->ip6af_down = up6->ip6af_down;
553 up6->ip6af_down->ip6af_up = af6;
554 up6->ip6af_down = af6;
555 }
556
557 /*
558 * To frag6_enq as remque is to insque.
559 */
560 void
frag6_deq(struct ip6asfrag * af6)561 frag6_deq(struct ip6asfrag *af6)
562 {
563
564 KASSERT(mutex_owned(&frag6_lock));
565
566 af6->ip6af_up->ip6af_down = af6->ip6af_down;
567 af6->ip6af_down->ip6af_up = af6->ip6af_up;
568 }
569
570 void
frag6_insque(struct ip6q * newq,struct ip6q * oldq)571 frag6_insque(struct ip6q *newq, struct ip6q *oldq)
572 {
573
574 KASSERT(mutex_owned(&frag6_lock));
575
576 newq->ip6q_prev = oldq;
577 newq->ip6q_next = oldq->ip6q_next;
578 oldq->ip6q_next->ip6q_prev= newq;
579 oldq->ip6q_next = newq;
580 }
581
582 void
frag6_remque(struct ip6q * p6)583 frag6_remque(struct ip6q *p6)
584 {
585
586 KASSERT(mutex_owned(&frag6_lock));
587
588 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
589 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
590 }
591
592 void
frag6_fasttimo(void)593 frag6_fasttimo(void)
594 {
595 mutex_enter(softnet_lock);
596 KERNEL_LOCK(1, NULL);
597
598 if (frag6_drainwanted) {
599 frag6_drain();
600 frag6_drainwanted = 0;
601 }
602
603 KERNEL_UNLOCK_ONE(NULL);
604 mutex_exit(softnet_lock);
605 }
606
607 /*
608 * IPv6 reassembling timer processing;
609 * if a timer expires on a reassembly
610 * queue, discard it.
611 */
612 void
frag6_slowtimo(void)613 frag6_slowtimo(void)
614 {
615 struct ip6q *q6;
616
617 mutex_enter(softnet_lock);
618 KERNEL_LOCK(1, NULL);
619
620 mutex_enter(&frag6_lock);
621 q6 = ip6q.ip6q_next;
622 if (q6)
623 while (q6 != &ip6q) {
624 --q6->ip6q_ttl;
625 q6 = q6->ip6q_next;
626 if (q6->ip6q_prev->ip6q_ttl == 0) {
627 IP6_STATINC(IP6_STAT_FRAGTIMEOUT);
628 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
629 frag6_freef(q6->ip6q_prev);
630 }
631 }
632 /*
633 * If we are over the maximum number of fragments
634 * (due to the limit being lowered), drain off
635 * enough to get down to the new limit.
636 */
637 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
638 ip6q.ip6q_prev) {
639 IP6_STATINC(IP6_STAT_FRAGOVERFLOW);
640 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
641 frag6_freef(ip6q.ip6q_prev);
642 }
643 mutex_exit(&frag6_lock);
644
645 KERNEL_UNLOCK_ONE(NULL);
646 mutex_exit(softnet_lock);
647
648 #if 0
649 /*
650 * Routing changes might produce a better route than we last used;
651 * make sure we notice eventually, even if forwarding only for one
652 * destination and the cache is never replaced.
653 */
654 rtcache_free(&ip6_forward_rt);
655 rtcache_free(&ipsrcchk_rt);
656 #endif
657
658 }
659
660 void
frag6_drainstub(void)661 frag6_drainstub(void)
662 {
663 frag6_drainwanted = 1;
664 }
665
666 /*
667 * Drain off all datagram fragments.
668 */
669 void
frag6_drain(void)670 frag6_drain(void)
671 {
672
673 if (mutex_tryenter(&frag6_lock)) {
674 while (ip6q.ip6q_next != &ip6q) {
675 IP6_STATINC(IP6_STAT_FRAGDROPPED);
676 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
677 frag6_freef(ip6q.ip6q_next);
678 }
679 mutex_exit(&frag6_lock);
680 }
681 }
682