1 /* $NetBSD: frag6.c,v 1.78 2024/04/19 05:04:06 ozaki-r 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 1.78 2024/04/19 05:04:06 ozaki-r Exp $");
35
36 #ifdef _KERNEL_OPT
37 #include "opt_net_mpsafe.h"
38 #endif
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/mbuf.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 /*
60 * IPv6 reassembly queue structure. Each fragment being reassembled is
61 * attached to one of these structures.
62 *
63 * XXX: Would be better to use TAILQ.
64 */
65 struct ip6q {
66 u_int32_t ip6q_head;
67 u_int16_t ip6q_len;
68 u_int8_t ip6q_nxt; /* ip6f_nxt in first fragment */
69 u_int8_t ip6q_hlim;
70 struct ip6asfrag *ip6q_down;
71 struct ip6asfrag *ip6q_up;
72 u_int32_t ip6q_ident;
73 u_int8_t ip6q_ttl;
74 struct in6_addr ip6q_src, ip6q_dst;
75 struct ip6q *ip6q_next;
76 struct ip6q *ip6q_prev;
77 int ip6q_unfrglen; /* len of unfragmentable part */
78 int ip6q_nfrag; /* # of fragments */
79 int ip6q_ipsec; /* IPsec flags */
80 };
81
82 struct ip6asfrag {
83 u_int32_t ip6af_head;
84 u_int16_t ip6af_len;
85 u_int8_t ip6af_nxt;
86 u_int8_t ip6af_hlim;
87 /* must not override the above members during reassembling */
88 struct ip6asfrag *ip6af_down;
89 struct ip6asfrag *ip6af_up;
90 struct mbuf *ip6af_m;
91 int ip6af_offset; /* offset in ip6af_m to next header */
92 int ip6af_frglen; /* fragmentable part length */
93 int ip6af_off; /* fragment offset */
94 bool ip6af_mff; /* more fragment bit in frag off */
95 };
96
97 static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *);
98 static void frag6_deq(struct ip6asfrag *);
99 static void frag6_insque(struct ip6q *, struct ip6q *);
100 static void frag6_remque(struct ip6q *);
101 static void frag6_freef(struct ip6q *);
102
103 static int frag6_drainwanted;
104
105 static u_int frag6_nfragpackets;
106 static u_int frag6_nfrags;
107 static struct ip6q ip6q; /* ip6 reassembly queue */
108
109 /* Protects ip6q */
110 static kmutex_t frag6_lock __cacheline_aligned;
111
112 /*
113 * Initialise reassembly queue and fragment identifier.
114 */
115 void
frag6_init(void)116 frag6_init(void)
117 {
118
119 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
120 mutex_init(&frag6_lock, MUTEX_DEFAULT, IPL_NONE);
121 }
122
123 static void
frag6_dropfrag(struct ip6q * q6)124 frag6_dropfrag(struct ip6q *q6)
125 {
126 frag6_remque(q6);
127 frag6_nfrags -= q6->ip6q_nfrag;
128 kmem_intr_free(q6, sizeof(*q6));
129 frag6_nfragpackets--;
130 }
131
132 /*
133 * IPv6 fragment input.
134 *
135 * In RFC2460, fragment and reassembly rule do not agree with each other,
136 * in terms of next header field handling in fragment header.
137 * While the sender will use the same value for all of the fragmented packets,
138 * receiver is suggested not to check the consistency.
139 *
140 * fragment rule (p20):
141 * (2) A Fragment header containing:
142 * The Next Header value that identifies the first header of
143 * the Fragmentable Part of the original packet.
144 * -> next header field is same for all fragments
145 *
146 * reassembly rule (p21):
147 * The Next Header field of the last header of the Unfragmentable
148 * Part is obtained from the Next Header field of the first
149 * fragment's Fragment header.
150 * -> should grab it from the first fragment only
151 *
152 * The following note also contradicts with fragment rule - noone is going to
153 * send different fragment with different next header field.
154 *
155 * additional note (p22):
156 * The Next Header values in the Fragment headers of different
157 * fragments of the same original packet may differ. Only the value
158 * from the Offset zero fragment packet is used for reassembly.
159 * -> should grab it from the first fragment only
160 *
161 * There is no explicit reason given in the RFC. Historical reason maybe?
162 *
163 * XXX: It would be better to use a pool, rather than kmem.
164 */
165 int
frag6_input(struct mbuf ** mp,int * offp,int proto)166 frag6_input(struct mbuf **mp, int *offp, int proto)
167 {
168 struct rtentry *rt;
169 struct mbuf *m = *mp, *t;
170 struct ip6_hdr *ip6;
171 struct ip6_frag *ip6f;
172 struct ip6q *q6;
173 struct ip6asfrag *af6, *ip6af, *af6dwn;
174 int offset = *offp, nxt, i, next;
175 int ipsecflags = m->m_flags & (M_DECRYPTED|M_AUTHIPHDR);
176 int first_frag = 0;
177 int fragoff, frgpartlen; /* must be larger than u_int16_t */
178 struct ifnet *dstifp;
179 static struct route ro;
180 union {
181 struct sockaddr dst;
182 struct sockaddr_in6 dst6;
183 } u;
184
185 ip6 = mtod(m, struct ip6_hdr *);
186 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
187 if (ip6f == NULL)
188 return IPPROTO_DONE;
189
190 dstifp = NULL;
191 /* find the destination interface of the packet. */
192 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);
193 if ((rt = rtcache_lookup(&ro, &u.dst)) != NULL)
194 dstifp = ((struct in6_ifaddr *)rt->rt_ifa)->ia_ifp;
195
196 /* jumbo payload can't contain a fragment header */
197 if (ip6->ip6_plen == 0) {
198 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
199 in6_ifstat_inc(dstifp, ifs6_reass_fail);
200 goto done;
201 }
202
203 /*
204 * Check whether fragment packet's fragment length is non-zero and
205 * multiple of 8 octets.
206 * sizeof(struct ip6_frag) == 8
207 * sizeof(struct ip6_hdr) = 40
208 */
209 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset
210 - sizeof(struct ip6_frag);
211 if ((frgpartlen == 0) ||
212 ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && (frgpartlen & 0x7) != 0)) {
213 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
214 offsetof(struct ip6_hdr, ip6_plen));
215 in6_ifstat_inc(dstifp, ifs6_reass_fail);
216 goto done;
217 }
218
219 IP6_STATINC(IP6_STAT_FRAGMENTS);
220 in6_ifstat_inc(dstifp, ifs6_reass_reqd);
221
222 /* offset now points to data portion */
223 offset += sizeof(struct ip6_frag);
224
225 /*
226 * RFC6946: A host that receives an IPv6 packet which includes
227 * a Fragment Header with the "Fragment Offset" equal to 0 and
228 * the "M" bit equal to 0 MUST process such packet in isolation
229 * from any other packets/fragments.
230 *
231 * XXX: Would be better to remove this fragment header entirely,
232 * for us not to get confused later when looking back at the
233 * previous headers in the chain.
234 */
235 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
236 if (fragoff == 0 && !(ip6f->ip6f_offlg & IP6F_MORE_FRAG)) {
237 IP6_STATINC(IP6_STAT_REASSEMBLED);
238 in6_ifstat_inc(dstifp, ifs6_reass_ok);
239 *offp = offset;
240 rtcache_unref(rt, &ro);
241 return ip6f->ip6f_nxt;
242 }
243
244 mutex_enter(&frag6_lock);
245
246 /*
247 * Enforce upper bound on number of fragments.
248 * If maxfrag is 0, never accept fragments.
249 * If maxfrag is -1, accept all fragments without limitation.
250 */
251 if (ip6_maxfrags < 0)
252 ;
253 else if (frag6_nfrags >= (u_int)ip6_maxfrags)
254 goto dropfrag;
255
256 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
257 if (ip6f->ip6f_ident == q6->ip6q_ident &&
258 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
259 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
260 break;
261
262 if (q6 != &ip6q) {
263 /* All fragments must have the same IPsec flags. */
264 if (q6->ip6q_ipsec != ipsecflags) {
265 goto dropfrag;
266 }
267 }
268
269 if (q6 == &ip6q) {
270 /*
271 * the first fragment to arrive, create a reassembly queue.
272 */
273 first_frag = 1;
274
275 /*
276 * Enforce upper bound on number of fragmented packets
277 * for which we attempt reassembly;
278 * If maxfragpackets is 0, never accept fragments.
279 * If maxfragpackets is -1, accept all fragments without
280 * limitation.
281 */
282 if (ip6_maxfragpackets < 0)
283 ;
284 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
285 goto dropfrag;
286 frag6_nfragpackets++;
287
288 q6 = kmem_intr_zalloc(sizeof(struct ip6q), KM_NOSLEEP);
289 if (q6 == NULL) {
290 goto dropfrag;
291 }
292 frag6_insque(q6, &ip6q);
293
294 /* ip6q_nxt will be filled afterwards, from 1st fragment */
295 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
296 q6->ip6q_ident = ip6f->ip6f_ident;
297 q6->ip6q_ttl = IPV6_FRAGTTL;
298 q6->ip6q_src = ip6->ip6_src;
299 q6->ip6q_dst = ip6->ip6_dst;
300 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
301 q6->ip6q_nfrag = 0;
302 q6->ip6q_ipsec = ipsecflags;
303 }
304
305 /*
306 * If it's the 1st fragment, record the length of the
307 * unfragmentable part and the next header of the fragment header.
308 */
309 if (fragoff == 0) {
310 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
311 sizeof(struct ip6_frag);
312 q6->ip6q_nxt = ip6f->ip6f_nxt;
313 }
314
315 /*
316 * Check that the reassembled packet would not exceed 65535 bytes
317 * in size. If it would exceed, discard the fragment and return an
318 * ICMP error.
319 */
320 if (q6->ip6q_unfrglen >= 0) {
321 /* The 1st fragment has already arrived. */
322 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
323 mutex_exit(&frag6_lock);
324 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
325 offset - sizeof(struct ip6_frag) +
326 offsetof(struct ip6_frag, ip6f_offlg));
327 goto done;
328 }
329 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
330 mutex_exit(&frag6_lock);
331 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
332 offset - sizeof(struct ip6_frag) +
333 offsetof(struct ip6_frag, ip6f_offlg));
334 goto done;
335 }
336
337 /*
338 * If it's the first fragment, do the above check for each
339 * fragment already stored in the reassembly queue.
340 */
341 if (fragoff == 0) {
342 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
343 af6 = af6dwn) {
344 af6dwn = af6->ip6af_down;
345
346 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
347 IPV6_MAXPACKET) {
348 struct mbuf *merr = af6->ip6af_m;
349 struct ip6_hdr *ip6err;
350 int erroff = af6->ip6af_offset;
351
352 /* dequeue the fragment. */
353 frag6_deq(af6);
354 kmem_intr_free(af6, sizeof(struct ip6asfrag));
355
356 /* adjust pointer. */
357 ip6err = mtod(merr, struct ip6_hdr *);
358
359 /*
360 * Restore source and destination addresses
361 * in the erroneous IPv6 header.
362 */
363 ip6err->ip6_src = q6->ip6q_src;
364 ip6err->ip6_dst = q6->ip6q_dst;
365
366 icmp6_error(merr, ICMP6_PARAM_PROB,
367 ICMP6_PARAMPROB_HEADER,
368 erroff - sizeof(struct ip6_frag) +
369 offsetof(struct ip6_frag, ip6f_offlg));
370 }
371 }
372 }
373
374 ip6af = kmem_intr_zalloc(sizeof(struct ip6asfrag), KM_NOSLEEP);
375 if (ip6af == NULL) {
376 goto dropfrag;
377 }
378 ip6af->ip6af_head = ip6->ip6_flow;
379 ip6af->ip6af_len = ip6->ip6_plen;
380 ip6af->ip6af_nxt = ip6->ip6_nxt;
381 ip6af->ip6af_hlim = ip6->ip6_hlim;
382 ip6af->ip6af_mff = (ip6f->ip6f_offlg & IP6F_MORE_FRAG) != 0;
383 ip6af->ip6af_off = fragoff;
384 ip6af->ip6af_frglen = frgpartlen;
385 ip6af->ip6af_offset = offset;
386 ip6af->ip6af_m = m;
387
388 if (first_frag) {
389 af6 = (struct ip6asfrag *)q6;
390 goto insert;
391 }
392
393 /*
394 * Find a segment which begins after this one does.
395 */
396 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
397 af6 = af6->ip6af_down)
398 if (af6->ip6af_off > ip6af->ip6af_off)
399 break;
400
401 /*
402 * If the incoming fragment overlaps some existing fragments in
403 * the reassembly queue - drop it as per RFC 5722.
404 */
405 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
406 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
407 - ip6af->ip6af_off;
408 if (i > 0) {
409 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
410 goto dropfrag;
411 }
412 }
413 if (af6 != (struct ip6asfrag *)q6) {
414 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
415 if (i > 0) {
416 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
417 goto dropfrag;
418 }
419 }
420
421 insert:
422 /*
423 * Stick new segment in its place.
424 */
425 frag6_enq(ip6af, af6->ip6af_up);
426 frag6_nfrags++;
427 q6->ip6q_nfrag++;
428
429 /*
430 * Check for complete reassembly.
431 */
432 next = 0;
433 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
434 af6 = af6->ip6af_down) {
435 if (af6->ip6af_off != next) {
436 mutex_exit(&frag6_lock);
437 goto done;
438 }
439 next += af6->ip6af_frglen;
440 }
441 if (af6->ip6af_up->ip6af_mff) {
442 mutex_exit(&frag6_lock);
443 goto done;
444 }
445
446 /*
447 * Reassembly is complete; concatenate fragments.
448 */
449 ip6af = q6->ip6q_down;
450 t = m = ip6af->ip6af_m;
451 af6 = ip6af->ip6af_down;
452 frag6_deq(ip6af);
453 while (af6 != (struct ip6asfrag *)q6) {
454 af6dwn = af6->ip6af_down;
455 frag6_deq(af6);
456 while (t->m_next)
457 t = t->m_next;
458 t->m_next = af6->ip6af_m;
459 m_adj(t->m_next, af6->ip6af_offset);
460 m_remove_pkthdr(t->m_next);
461 kmem_intr_free(af6, sizeof(struct ip6asfrag));
462 af6 = af6dwn;
463 }
464
465 /* adjust offset to point where the original next header starts */
466 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
467 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
468 next += offset - sizeof(struct ip6_hdr);
469 if ((u_int)next > IPV6_MAXPACKET) {
470 frag6_dropfrag(q6);
471 goto dropfrag;
472 }
473 ip6 = mtod(m, struct ip6_hdr *);
474 ip6->ip6_plen = htons(next);
475 ip6->ip6_src = q6->ip6q_src;
476 ip6->ip6_dst = q6->ip6q_dst;
477 nxt = q6->ip6q_nxt;
478
479 /*
480 * Delete frag6 header.
481 */
482 if (m->m_len >= offset + sizeof(struct ip6_frag)) {
483 memmove((char *)ip6 + sizeof(struct ip6_frag), ip6, offset);
484 m->m_data += sizeof(struct ip6_frag);
485 m->m_len -= sizeof(struct ip6_frag);
486 } else {
487 /* this comes with no copy if the boundary is on cluster */
488 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
489 frag6_dropfrag(q6);
490 goto dropfrag;
491 }
492 m_adj(t, sizeof(struct ip6_frag));
493 m_cat(m, t);
494 }
495
496 frag6_dropfrag(q6);
497
498 {
499 KASSERT(m->m_flags & M_PKTHDR);
500 int plen = 0;
501 for (t = m; t; t = t->m_next) {
502 plen += t->m_len;
503 }
504 m->m_pkthdr.len = plen;
505 /* XXX XXX: clear csum_flags? */
506 }
507
508 /*
509 * Restore NXT to the original.
510 */
511 {
512 const int prvnxt = ip6_get_prevhdr(m, offset);
513 uint8_t *prvnxtp;
514
515 IP6_EXTHDR_GET(prvnxtp, uint8_t *, m, prvnxt,
516 sizeof(*prvnxtp));
517 if (prvnxtp == NULL) {
518 goto dropfrag;
519 }
520 *prvnxtp = nxt;
521 }
522
523 IP6_STATINC(IP6_STAT_REASSEMBLED);
524 in6_ifstat_inc(dstifp, ifs6_reass_ok);
525 rtcache_unref(rt, &ro);
526 mutex_exit(&frag6_lock);
527
528 /*
529 * Tell launch routine the next header.
530 */
531 *mp = m;
532 *offp = offset;
533 return nxt;
534
535 dropfrag:
536 mutex_exit(&frag6_lock);
537 in6_ifstat_inc(dstifp, ifs6_reass_fail);
538 IP6_STATINC(IP6_STAT_FRAGDROPPED);
539 m_freem(m);
540 done:
541 rtcache_unref(rt, &ro);
542 return IPPROTO_DONE;
543 }
544
545 int
ip6_reass_packet(struct mbuf ** mp,int offset)546 ip6_reass_packet(struct mbuf **mp, int offset)
547 {
548
549 if (frag6_input(mp, &offset, IPPROTO_IPV6) == IPPROTO_DONE) {
550 *mp = NULL;
551 return EINVAL;
552 }
553 return 0;
554 }
555
556 /*
557 * Free a fragment reassembly header and all
558 * associated datagrams.
559 */
560 static void
frag6_freef(struct ip6q * q6)561 frag6_freef(struct ip6q *q6)
562 {
563 struct ip6asfrag *af6, *down6;
564
565 KASSERT(mutex_owned(&frag6_lock));
566
567 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
568 af6 = down6) {
569 struct mbuf *m = af6->ip6af_m;
570
571 down6 = af6->ip6af_down;
572 frag6_deq(af6);
573
574 /*
575 * Return ICMP time exceeded error for the 1st fragment.
576 * Just free other fragments.
577 */
578 if (af6->ip6af_off == 0) {
579 struct ip6_hdr *ip6;
580
581 /* adjust pointer */
582 ip6 = mtod(m, struct ip6_hdr *);
583
584 /* restore source and destination addresses */
585 ip6->ip6_src = q6->ip6q_src;
586 ip6->ip6_dst = q6->ip6q_dst;
587
588 icmp6_error(m, ICMP6_TIME_EXCEEDED,
589 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
590 } else {
591 m_freem(m);
592 }
593 kmem_intr_free(af6, sizeof(struct ip6asfrag));
594 }
595
596 frag6_dropfrag(q6);
597 }
598
599 /*
600 * Put an ip fragment on a reassembly chain.
601 * Like insque, but pointers in middle of structure.
602 */
603 void
frag6_enq(struct ip6asfrag * af6,struct ip6asfrag * up6)604 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6)
605 {
606
607 KASSERT(mutex_owned(&frag6_lock));
608
609 af6->ip6af_up = up6;
610 af6->ip6af_down = up6->ip6af_down;
611 up6->ip6af_down->ip6af_up = af6;
612 up6->ip6af_down = af6;
613 }
614
615 /*
616 * To frag6_enq as remque is to insque.
617 */
618 void
frag6_deq(struct ip6asfrag * af6)619 frag6_deq(struct ip6asfrag *af6)
620 {
621
622 KASSERT(mutex_owned(&frag6_lock));
623
624 af6->ip6af_up->ip6af_down = af6->ip6af_down;
625 af6->ip6af_down->ip6af_up = af6->ip6af_up;
626 }
627
628 /*
629 * Insert newq after oldq.
630 */
631 void
frag6_insque(struct ip6q * newq,struct ip6q * oldq)632 frag6_insque(struct ip6q *newq, struct ip6q *oldq)
633 {
634
635 KASSERT(mutex_owned(&frag6_lock));
636
637 newq->ip6q_prev = oldq;
638 newq->ip6q_next = oldq->ip6q_next;
639 oldq->ip6q_next->ip6q_prev = newq;
640 oldq->ip6q_next = newq;
641 }
642
643 /*
644 * Unlink p6.
645 */
646 void
frag6_remque(struct ip6q * p6)647 frag6_remque(struct ip6q *p6)
648 {
649
650 KASSERT(mutex_owned(&frag6_lock));
651
652 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
653 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
654 }
655
656 void
frag6_fasttimo(void)657 frag6_fasttimo(void)
658 {
659
660 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
661
662 if (frag6_drainwanted) {
663 frag6_drain();
664 frag6_drainwanted = 0;
665 }
666
667 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
668 }
669
670 /*
671 * IPv6 reassembling timer processing;
672 * if a timer expires on a reassembly
673 * queue, discard it.
674 */
675 void
frag6_slowtimo(void)676 frag6_slowtimo(void)
677 {
678 struct ip6q *q6;
679
680 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
681
682 mutex_enter(&frag6_lock);
683 q6 = ip6q.ip6q_next;
684 if (q6) {
685 while (q6 != &ip6q) {
686 --q6->ip6q_ttl;
687 q6 = q6->ip6q_next;
688 if (q6->ip6q_prev->ip6q_ttl == 0) {
689 IP6_STATINC(IP6_STAT_FRAGTIMEOUT);
690 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
691 frag6_freef(q6->ip6q_prev);
692 }
693 }
694 }
695
696 /*
697 * If we are over the maximum number of fragments
698 * (due to the limit being lowered), drain off
699 * enough to get down to the new limit.
700 */
701 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
702 ip6q.ip6q_prev) {
703 IP6_STATINC(IP6_STAT_FRAGOVERFLOW);
704 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
705 frag6_freef(ip6q.ip6q_prev);
706 }
707 mutex_exit(&frag6_lock);
708
709 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
710
711 #if 0
712 /*
713 * Routing changes might produce a better route than we last used;
714 * make sure we notice eventually, even if forwarding only for one
715 * destination and the cache is never replaced.
716 */
717 rtcache_free(&ip6_forward_rt);
718 rtcache_free(&ipsrcchk_rt);
719 #endif
720 }
721
722 void
frag6_drainstub(void)723 frag6_drainstub(void)
724 {
725 frag6_drainwanted = 1;
726 }
727
728 /*
729 * Drain off all datagram fragments.
730 */
731 void
frag6_drain(void)732 frag6_drain(void)
733 {
734
735 if (mutex_tryenter(&frag6_lock)) {
736 while (ip6q.ip6q_next != &ip6q) {
737 IP6_STATINC(IP6_STAT_FRAGDROPPED);
738 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
739 frag6_freef(ip6q.ip6q_next);
740 }
741 mutex_exit(&frag6_lock);
742 }
743 }
744