FreeBSD/Linux Kernel Cross Reference
sys/netinet6/frag6.c
1 /* $NetBSD: frag6.c,v 1.76 2022/10/21 09:21:17 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 1.76 2022/10/21 09:21:17 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
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 /*
124 * IPv6 fragment input.
125 *
126 * In RFC2460, fragment and reassembly rule do not agree with each other,
127 * in terms of next header field handling in fragment header.
128 * While the sender will use the same value for all of the fragmented packets,
129 * receiver is suggested not to check the consistency.
130 *
131 * fragment rule (p20):
132 * (2) A Fragment header containing:
133 * The Next Header value that identifies the first header of
134 * the Fragmentable Part of the original packet.
135 * -> next header field is same for all fragments
136 *
137 * reassembly rule (p21):
138 * The Next Header field of the last header of the Unfragmentable
139 * Part is obtained from the Next Header field of the first
140 * fragment's Fragment header.
141 * -> should grab it from the first fragment only
142 *
143 * The following note also contradicts with fragment rule - noone is going to
144 * send different fragment with different next header field.
145 *
146 * additional note (p22):
147 * The Next Header values in the Fragment headers of different
148 * fragments of the same original packet may differ. Only the value
149 * from the Offset zero fragment packet is used for reassembly.
150 * -> should grab it from the first fragment only
151 *
152 * There is no explicit reason given in the RFC. Historical reason maybe?
153 *
154 * XXX: It would be better to use a pool, rather than kmem.
155 */
156 int
157 frag6_input(struct mbuf **mp, int *offp, int proto)
158 {
159 struct rtentry *rt;
160 struct mbuf *m = *mp, *t;
161 struct ip6_hdr *ip6;
162 struct ip6_frag *ip6f;
163 struct ip6q *q6;
164 struct ip6asfrag *af6, *ip6af, *af6dwn;
165 int offset = *offp, nxt, i, next;
166 int ipsecflags = m->m_flags & (M_DECRYPTED|M_AUTHIPHDR);
167 int first_frag = 0;
168 int fragoff, frgpartlen; /* must be larger than u_int16_t */
169 struct ifnet *dstifp;
170 static struct route ro;
171 union {
172 struct sockaddr dst;
173 struct sockaddr_in6 dst6;
174 } u;
175
176 ip6 = mtod(m, struct ip6_hdr *);
177 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
178 if (ip6f == NULL)
179 return IPPROTO_DONE;
180
181 dstifp = NULL;
182 /* find the destination interface of the packet. */
183 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);
184 if ((rt = rtcache_lookup(&ro, &u.dst)) != NULL)
185 dstifp = ((struct in6_ifaddr *)rt->rt_ifa)->ia_ifp;
186
187 /* jumbo payload can't contain a fragment header */
188 if (ip6->ip6_plen == 0) {
189 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
190 in6_ifstat_inc(dstifp, ifs6_reass_fail);
191 goto done;
192 }
193
194 /*
195 * Check whether fragment packet's fragment length is non-zero and
196 * multiple of 8 octets.
197 * sizeof(struct ip6_frag) == 8
198 * sizeof(struct ip6_hdr) = 40
199 */
200 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
201 (((ntohs(ip6->ip6_plen) - offset) == 0) ||
202 ((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
203 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
204 offsetof(struct ip6_hdr, ip6_plen));
205 in6_ifstat_inc(dstifp, ifs6_reass_fail);
206 goto done;
207 }
208
209 IP6_STATINC(IP6_STAT_FRAGMENTS);
210 in6_ifstat_inc(dstifp, ifs6_reass_reqd);
211
212 /* offset now points to data portion */
213 offset += sizeof(struct ip6_frag);
214
215 /*
216 * RFC6946: A host that receives an IPv6 packet which includes
217 * a Fragment Header with the "Fragment Offset" equal to 0 and
218 * the "M" bit equal to 0 MUST process such packet in isolation
219 * from any other packets/fragments.
220 *
221 * XXX: Would be better to remove this fragment header entirely,
222 * for us not to get confused later when looking back at the
223 * previous headers in the chain.
224 */
225 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
226 if (fragoff == 0 && !(ip6f->ip6f_offlg & IP6F_MORE_FRAG)) {
227 IP6_STATINC(IP6_STAT_REASSEMBLED);
228 in6_ifstat_inc(dstifp, ifs6_reass_ok);
229 *offp = offset;
230 rtcache_unref(rt, &ro);
231 return ip6f->ip6f_nxt;
232 }
233
234 mutex_enter(&frag6_lock);
235
236 /*
237 * Enforce upper bound on number of fragments.
238 * If maxfrag is 0, never accept fragments.
239 * If maxfrag is -1, accept all fragments without limitation.
240 */
241 if (ip6_maxfrags < 0)
242 ;
243 else if (frag6_nfrags >= (u_int)ip6_maxfrags)
244 goto dropfrag;
245
246 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
247 if (ip6f->ip6f_ident == q6->ip6q_ident &&
248 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
249 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
250 break;
251
252 if (q6 != &ip6q) {
253 /* All fragments must have the same IPsec flags. */
254 if (q6->ip6q_ipsec != ipsecflags) {
255 goto dropfrag;
256 }
257 }
258
259 if (q6 == &ip6q) {
260 /*
261 * the first fragment to arrive, create a reassembly queue.
262 */
263 first_frag = 1;
264
265 /*
266 * Enforce upper bound on number of fragmented packets
267 * for which we attempt reassembly;
268 * If maxfragpackets is 0, never accept fragments.
269 * If maxfragpackets is -1, accept all fragments without
270 * limitation.
271 */
272 if (ip6_maxfragpackets < 0)
273 ;
274 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
275 goto dropfrag;
276 frag6_nfragpackets++;
277
278 q6 = kmem_intr_zalloc(sizeof(struct ip6q), KM_NOSLEEP);
279 if (q6 == NULL) {
280 goto dropfrag;
281 }
282 frag6_insque(q6, &ip6q);
283
284 /* ip6q_nxt will be filled afterwards, from 1st fragment */
285 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
286 q6->ip6q_ident = ip6f->ip6f_ident;
287 q6->ip6q_ttl = IPV6_FRAGTTL;
288 q6->ip6q_src = ip6->ip6_src;
289 q6->ip6q_dst = ip6->ip6_dst;
290 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
291 q6->ip6q_nfrag = 0;
292 q6->ip6q_ipsec = ipsecflags;
293 }
294
295 /*
296 * If it's the 1st fragment, record the length of the
297 * unfragmentable part and the next header of the fragment header.
298 */
299 if (fragoff == 0) {
300 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
301 sizeof(struct ip6_frag);
302 q6->ip6q_nxt = ip6f->ip6f_nxt;
303 }
304
305 /*
306 * Check that the reassembled packet would not exceed 65535 bytes
307 * in size. If it would exceed, discard the fragment and return an
308 * ICMP error.
309 */
310 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
311 if (q6->ip6q_unfrglen >= 0) {
312 /* The 1st fragment has already arrived. */
313 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
314 mutex_exit(&frag6_lock);
315 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
316 offset - sizeof(struct ip6_frag) +
317 offsetof(struct ip6_frag, ip6f_offlg));
318 goto done;
319 }
320 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
321 mutex_exit(&frag6_lock);
322 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
323 offset - sizeof(struct ip6_frag) +
324 offsetof(struct ip6_frag, ip6f_offlg));
325 goto done;
326 }
327
328 /*
329 * If it's the first fragment, do the above check for each
330 * fragment already stored in the reassembly queue.
331 */
332 if (fragoff == 0) {
333 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
334 af6 = af6dwn) {
335 af6dwn = af6->ip6af_down;
336
337 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
338 IPV6_MAXPACKET) {
339 struct mbuf *merr = af6->ip6af_m;
340 struct ip6_hdr *ip6err;
341 int erroff = af6->ip6af_offset;
342
343 /* dequeue the fragment. */
344 frag6_deq(af6);
345 kmem_intr_free(af6, sizeof(struct ip6asfrag));
346
347 /* adjust pointer. */
348 ip6err = mtod(merr, struct ip6_hdr *);
349
350 /*
351 * Restore source and destination addresses
352 * in the erroneous IPv6 header.
353 */
354 ip6err->ip6_src = q6->ip6q_src;
355 ip6err->ip6_dst = q6->ip6q_dst;
356
357 icmp6_error(merr, ICMP6_PARAM_PROB,
358 ICMP6_PARAMPROB_HEADER,
359 erroff - sizeof(struct ip6_frag) +
360 offsetof(struct ip6_frag, ip6f_offlg));
361 }
362 }
363 }
364
365 ip6af = kmem_intr_zalloc(sizeof(struct ip6asfrag), KM_NOSLEEP);
366 if (ip6af == NULL) {
367 goto dropfrag;
368 }
369 ip6af->ip6af_head = ip6->ip6_flow;
370 ip6af->ip6af_len = ip6->ip6_plen;
371 ip6af->ip6af_nxt = ip6->ip6_nxt;
372 ip6af->ip6af_hlim = ip6->ip6_hlim;
373 ip6af->ip6af_mff = (ip6f->ip6f_offlg & IP6F_MORE_FRAG) != 0;
374 ip6af->ip6af_off = fragoff;
375 ip6af->ip6af_frglen = frgpartlen;
376 ip6af->ip6af_offset = offset;
377 ip6af->ip6af_m = m;
378
379 if (first_frag) {
380 af6 = (struct ip6asfrag *)q6;
381 goto insert;
382 }
383
384 /*
385 * Find a segment which begins after this one does.
386 */
387 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
388 af6 = af6->ip6af_down)
389 if (af6->ip6af_off > ip6af->ip6af_off)
390 break;
391
392 /*
393 * If the incoming fragment overlaps some existing fragments in
394 * the reassembly queue - drop it as per RFC 5722.
395 */
396 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
397 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
398 - ip6af->ip6af_off;
399 if (i > 0) {
400 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
401 goto dropfrag;
402 }
403 }
404 if (af6 != (struct ip6asfrag *)q6) {
405 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
406 if (i > 0) {
407 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
408 goto dropfrag;
409 }
410 }
411
412 insert:
413 /*
414 * Stick new segment in its place.
415 */
416 frag6_enq(ip6af, af6->ip6af_up);
417 frag6_nfrags++;
418 q6->ip6q_nfrag++;
419
420 /*
421 * Check for complete reassembly.
422 */
423 next = 0;
424 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
425 af6 = af6->ip6af_down) {
426 if (af6->ip6af_off != next) {
427 mutex_exit(&frag6_lock);
428 goto done;
429 }
430 next += af6->ip6af_frglen;
431 }
432 if (af6->ip6af_up->ip6af_mff) {
433 mutex_exit(&frag6_lock);
434 goto done;
435 }
436
437 /*
438 * Reassembly is complete; concatenate fragments.
439 */
440 ip6af = q6->ip6q_down;
441 t = m = ip6af->ip6af_m;
442 af6 = ip6af->ip6af_down;
443 frag6_deq(ip6af);
444 while (af6 != (struct ip6asfrag *)q6) {
445 af6dwn = af6->ip6af_down;
446 frag6_deq(af6);
447 while (t->m_next)
448 t = t->m_next;
449 t->m_next = af6->ip6af_m;
450 m_adj(t->m_next, af6->ip6af_offset);
451 m_remove_pkthdr(t->m_next);
452 kmem_intr_free(af6, sizeof(struct ip6asfrag));
453 af6 = af6dwn;
454 }
455
456 /* adjust offset to point where the original next header starts */
457 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
458 kmem_intr_free(ip6af, sizeof(struct ip6asfrag));
459 ip6 = mtod(m, struct ip6_hdr *);
460 ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr));
461 ip6->ip6_src = q6->ip6q_src;
462 ip6->ip6_dst = q6->ip6q_dst;
463 nxt = q6->ip6q_nxt;
464
465 /*
466 * Delete frag6 header.
467 */
468 if (m->m_len >= offset + sizeof(struct ip6_frag)) {
469 memmove((char *)ip6 + sizeof(struct ip6_frag), ip6, offset);
470 m->m_data += sizeof(struct ip6_frag);
471 m->m_len -= sizeof(struct ip6_frag);
472 } else {
473 /* this comes with no copy if the boundary is on cluster */
474 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
475 frag6_remque(q6);
476 frag6_nfrags -= q6->ip6q_nfrag;
477 kmem_intr_free(q6, sizeof(struct ip6q));
478 frag6_nfragpackets--;
479 goto dropfrag;
480 }
481 m_adj(t, sizeof(struct ip6_frag));
482 m_cat(m, t);
483 }
484
485 frag6_remque(q6);
486 frag6_nfrags -= q6->ip6q_nfrag;
487 kmem_intr_free(q6, sizeof(struct ip6q));
488 frag6_nfragpackets--;
489
490 {
491 KASSERT(m->m_flags & M_PKTHDR);
492 int plen = 0;
493 for (t = m; t; t = t->m_next) {
494 plen += t->m_len;
495 }
496 m->m_pkthdr.len = plen;
497 /* XXX XXX: clear csum_flags? */
498 }
499
500 /*
501 * Restore NXT to the original.
502 */
503 {
504 const int prvnxt = ip6_get_prevhdr(m, offset);
505 uint8_t *prvnxtp;
506
507 IP6_EXTHDR_GET(prvnxtp, uint8_t *, m, prvnxt,
508 sizeof(*prvnxtp));
509 if (prvnxtp == NULL) {
510 goto dropfrag;
511 }
512 *prvnxtp = nxt;
513 }
514
515 IP6_STATINC(IP6_STAT_REASSEMBLED);
516 in6_ifstat_inc(dstifp, ifs6_reass_ok);
517 rtcache_unref(rt, &ro);
518 mutex_exit(&frag6_lock);
519
520 /*
521 * Tell launch routine the next header.
522 */
523 *mp = m;
524 *offp = offset;
525 return nxt;
526
527 dropfrag:
528 mutex_exit(&frag6_lock);
529 in6_ifstat_inc(dstifp, ifs6_reass_fail);
530 IP6_STATINC(IP6_STAT_FRAGDROPPED);
531 m_freem(m);
532 done:
533 rtcache_unref(rt, &ro);
534 return IPPROTO_DONE;
535 }
536
537 int
538 ip6_reass_packet(struct mbuf **mp, int offset)
539 {
540
541 if (frag6_input(mp, &offset, IPPROTO_IPV6) == IPPROTO_DONE) {
542 *mp = NULL;
543 return EINVAL;
544 }
545 return 0;
546 }
547
548 /*
549 * Free a fragment reassembly header and all
550 * associated datagrams.
551 */
552 static void
553 frag6_freef(struct ip6q *q6)
554 {
555 struct ip6asfrag *af6, *down6;
556
557 KASSERT(mutex_owned(&frag6_lock));
558
559 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
560 af6 = down6) {
561 struct mbuf *m = af6->ip6af_m;
562
563 down6 = af6->ip6af_down;
564 frag6_deq(af6);
565
566 /*
567 * Return ICMP time exceeded error for the 1st fragment.
568 * Just free other fragments.
569 */
570 if (af6->ip6af_off == 0) {
571 struct ip6_hdr *ip6;
572
573 /* adjust pointer */
574 ip6 = mtod(m, struct ip6_hdr *);
575
576 /* restore source and destination addresses */
577 ip6->ip6_src = q6->ip6q_src;
578 ip6->ip6_dst = q6->ip6q_dst;
579
580 icmp6_error(m, ICMP6_TIME_EXCEEDED,
581 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
582 } else {
583 m_freem(m);
584 }
585 kmem_intr_free(af6, sizeof(struct ip6asfrag));
586 }
587
588 frag6_remque(q6);
589 frag6_nfrags -= q6->ip6q_nfrag;
590 kmem_intr_free(q6, sizeof(struct ip6q));
591 frag6_nfragpackets--;
592 }
593
594 /*
595 * Put an ip fragment on a reassembly chain.
596 * Like insque, but pointers in middle of structure.
597 */
598 void
599 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6)
600 {
601
602 KASSERT(mutex_owned(&frag6_lock));
603
604 af6->ip6af_up = up6;
605 af6->ip6af_down = up6->ip6af_down;
606 up6->ip6af_down->ip6af_up = af6;
607 up6->ip6af_down = af6;
608 }
609
610 /*
611 * To frag6_enq as remque is to insque.
612 */
613 void
614 frag6_deq(struct ip6asfrag *af6)
615 {
616
617 KASSERT(mutex_owned(&frag6_lock));
618
619 af6->ip6af_up->ip6af_down = af6->ip6af_down;
620 af6->ip6af_down->ip6af_up = af6->ip6af_up;
621 }
622
623 /*
624 * Insert newq after oldq.
625 */
626 void
627 frag6_insque(struct ip6q *newq, struct ip6q *oldq)
628 {
629
630 KASSERT(mutex_owned(&frag6_lock));
631
632 newq->ip6q_prev = oldq;
633 newq->ip6q_next = oldq->ip6q_next;
634 oldq->ip6q_next->ip6q_prev = newq;
635 oldq->ip6q_next = newq;
636 }
637
638 /*
639 * Unlink p6.
640 */
641 void
642 frag6_remque(struct ip6q *p6)
643 {
644
645 KASSERT(mutex_owned(&frag6_lock));
646
647 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
648 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
649 }
650
651 void
652 frag6_fasttimo(void)
653 {
654
655 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
656
657 if (frag6_drainwanted) {
658 frag6_drain();
659 frag6_drainwanted = 0;
660 }
661
662 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
663 }
664
665 /*
666 * IPv6 reassembling timer processing;
667 * if a timer expires on a reassembly
668 * queue, discard it.
669 */
670 void
671 frag6_slowtimo(void)
672 {
673 struct ip6q *q6;
674
675 SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
676
677 mutex_enter(&frag6_lock);
678 q6 = ip6q.ip6q_next;
679 if (q6) {
680 while (q6 != &ip6q) {
681 --q6->ip6q_ttl;
682 q6 = q6->ip6q_next;
683 if (q6->ip6q_prev->ip6q_ttl == 0) {
684 IP6_STATINC(IP6_STAT_FRAGTIMEOUT);
685 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
686 frag6_freef(q6->ip6q_prev);
687 }
688 }
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 IP6_STATINC(IP6_STAT_FRAGOVERFLOW);
699 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
700 frag6_freef(ip6q.ip6q_prev);
701 }
702 mutex_exit(&frag6_lock);
703
704 SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
705
706 #if 0
707 /*
708 * Routing changes might produce a better route than we last used;
709 * make sure we notice eventually, even if forwarding only for one
710 * destination and the cache is never replaced.
711 */
712 rtcache_free(&ip6_forward_rt);
713 rtcache_free(&ipsrcchk_rt);
714 #endif
715 }
716
717 void
718 frag6_drainstub(void)
719 {
720 frag6_drainwanted = 1;
721 }
722
723 /*
724 * Drain off all datagram fragments.
725 */
726 void
727 frag6_drain(void)
728 {
729
730 if (mutex_tryenter(&frag6_lock)) {
731 while (ip6q.ip6q_next != &ip6q) {
732 IP6_STATINC(IP6_STAT_FRAGDROPPED);
733 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
734 frag6_freef(ip6q.ip6q_next);
735 }
736 mutex_exit(&frag6_lock);
737 }
738 }
Cache object: fd5d40f8c1df979fc7218b4e2fc8c437
|