1 /* $FreeBSD: src/sys/netinet6/frag6.c,v 1.2.2.6 2002/04/28 05:40:26 suz Exp $ */
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 #include <sys/thread2.h>
45
46 #include <net/if.h>
47 #include <net/route.h>
48 #include <net/netisr2.h>
49 #include <net/netmsg2.h>
50
51 #include <netinet/in.h>
52 #include <netinet/in_var.h>
53 #include <netinet/ip6.h>
54 #include <netinet6/ip6_var.h>
55 #include <netinet/icmp6.h>
56
57 #include <net/net_osdep.h>
58
59 #define FRAG6_SLOWTIMO (hz / PR_SLOWHZ)
60
61 /*
62 * Define it to get a correct behavior on per-interface statistics.
63 * You will need to perform an extra routing table lookup, per fragment,
64 * to do it. This may, or may not be, a performance hit.
65 */
66 #define IN6_IFSTAT_STRICT
67
68 static void frag6_enq (struct ip6asfrag *, struct ip6asfrag *);
69 static void frag6_deq (struct ip6asfrag *);
70 static void frag6_insque (struct ip6q *, struct ip6q *);
71 static void frag6_remque (struct ip6q *);
72 static void frag6_freef (struct ip6q *);
73 static void frag6_slowtimo_dispatch (netmsg_t);
74 static void frag6_slowtimo (void *);
75 static void frag6_drain_dispatch (netmsg_t);
76
77 /* XXX we eventually need splreass6, or some real semaphore */
78 int frag6_doing_reass;
79 u_int frag6_nfragpackets;
80 u_int frag6_nfrags;
81 struct ip6q ip6q; /* ip6 reassemble queue */
82
83 /* FreeBSD tweak */
84 MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header");
85
86 static struct callout frag6_slowtimo_ch;
87 static struct netmsg_base frag6_slowtimo_nmsg;
88 static struct netmsg_base frag6_drain_nmsg;
89 static volatile int frag6_draining;
90
91 /*
92 * Initialise reassembly queue and fragment identifier.
93 */
94 void
frag6_init(void)95 frag6_init(void)
96 {
97 struct timeval tv;
98
99 ip6_maxfragpackets = nmbclusters / 4;
100 ip6_maxfrags = nmbclusters / 4;
101
102 /*
103 * in many cases, random() here does NOT return random number
104 * as initialization during bootstrap time occur in fixed order.
105 */
106 microtime(&tv);
107 ip6_id = krandom() ^ tv.tv_usec;
108 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
109
110 netmsg_init(&frag6_drain_nmsg, NULL, &netisr_adone_rport,
111 MSGF_PRIORITY, frag6_drain_dispatch);
112
113 callout_init_mp(&frag6_slowtimo_ch);
114 netmsg_init(&frag6_slowtimo_nmsg, NULL, &netisr_adone_rport,
115 MSGF_PRIORITY, frag6_slowtimo_dispatch);
116
117 callout_reset_bycpu(&frag6_slowtimo_ch, FRAG6_SLOWTIMO,
118 frag6_slowtimo, NULL, 0);
119 }
120
121 /*
122 * In RFC2460, fragment and reassembly rule do not agree with each other,
123 * in terms of next header field handling in fragment header.
124 * While the sender will use the same value for all of the fragmented packets,
125 * receiver is suggested not to check the consistency.
126 *
127 * fragment rule (p20):
128 * (2) A Fragment header containing:
129 * The Next Header value that identifies the first header of
130 * the Fragmentable Part of the original packet.
131 * -> next header field is same for all fragments
132 *
133 * reassembly rule (p21):
134 * The Next Header field of the last header of the Unfragmentable
135 * Part is obtained from the Next Header field of the first
136 * fragment's Fragment header.
137 * -> should grab it from the first fragment only
138 *
139 * The following note also contradicts with fragment rule - noone is going to
140 * send different fragment with different next header field.
141 *
142 * additional note (p22):
143 * The Next Header values in the Fragment headers of different
144 * fragments of the same original packet may differ. Only the value
145 * from the Offset zero fragment packet is used for reassembly.
146 * -> should grab it from the first fragment only
147 *
148 * There is no explicit reason given in the RFC. Historical reason maybe?
149 */
150 /*
151 * Fragment input
152 */
153 int
frag6_input(struct mbuf ** mp,int * offp,int proto)154 frag6_input(struct mbuf **mp, int *offp, int proto)
155 {
156 struct mbuf *m = *mp, *t;
157 struct ip6_hdr *ip6;
158 struct ip6_frag *ip6f;
159 struct ip6q *q6;
160 struct ip6asfrag *af6, *ip6af, *af6dwn;
161 int offset = *offp, nxt, i, next;
162 int first_frag = 0;
163 int fragoff, frgpartlen; /* must be larger than u_int16_t */
164 struct ifnet *dstifp;
165 #ifdef IN6_IFSTAT_STRICT
166 static struct route_in6 ro;
167 struct sockaddr_in6 *dst;
168 #endif
169
170 ip6 = mtod(m, struct ip6_hdr *);
171 #ifndef PULLDOWN_TEST
172 IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
173 ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
174 #else
175 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
176 if (ip6f == NULL)
177 return IPPROTO_DONE;
178 #endif
179
180 dstifp = NULL;
181 #ifdef IN6_IFSTAT_STRICT
182 /* find the destination interface of the packet. */
183 dst = (struct sockaddr_in6 *)&ro.ro_dst;
184 if (ro.ro_rt &&
185 (!(ro.ro_rt->rt_flags & RTF_UP) ||
186 !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
187 rtfree(ro.ro_rt);
188 ro.ro_rt = NULL;
189 }
190 if (ro.ro_rt == NULL) {
191 bzero(dst, sizeof(*dst));
192 dst->sin6_family = AF_INET6;
193 dst->sin6_len = sizeof(struct sockaddr_in6);
194 dst->sin6_addr = ip6->ip6_dst;
195 }
196 rtalloc((struct route *)&ro);
197 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
198 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
199 #else
200 /* we are violating the spec, this is not the destination interface */
201 if (m->m_flags & M_PKTHDR)
202 dstifp = m->m_pkthdr.rcvif;
203 #endif
204
205 /* jumbo payload can't contain a fragment header */
206 if (ip6->ip6_plen == 0) {
207 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
208 in6_ifstat_inc(dstifp, ifs6_reass_fail);
209 return IPPROTO_DONE;
210 }
211
212 /*
213 * check whether fragment packet's fragment length is
214 * multiple of 8 octets.
215 * sizeof(struct ip6_frag) == 8
216 * sizeof(struct ip6_hdr) = 40
217 */
218 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
219 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
220 icmp6_error(m, ICMP6_PARAM_PROB,
221 ICMP6_PARAMPROB_HEADER,
222 offsetof(struct ip6_hdr, ip6_plen));
223 in6_ifstat_inc(dstifp, ifs6_reass_fail);
224 return IPPROTO_DONE;
225 }
226
227 ip6stat.ip6s_fragments++;
228 in6_ifstat_inc(dstifp, ifs6_reass_reqd);
229
230 /* offset now points to data portion */
231 offset += sizeof(struct ip6_frag);
232
233 frag6_doing_reass = 1;
234
235 /*
236 * Enforce upper bound on number of fragments.
237 * If maxfrag is 0, never accept fragments.
238 * If maxfrag is -1, accept all fragments without limitation.
239 */
240 if (ip6_maxfrags < 0)
241 ;
242 else if (frag6_nfrags >= (u_int)ip6_maxfrags)
243 goto dropfrag;
244
245 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
246 if (ip6f->ip6f_ident == q6->ip6q_ident &&
247 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
248 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
249 break;
250
251 if (q6 == &ip6q) {
252 /*
253 * the first fragment to arrive, create a reassembly queue.
254 */
255 first_frag = 1;
256
257 /*
258 * Enforce upper bound on number of fragmented packets
259 * for which we attempt reassembly;
260 * If maxfrag is 0, never accept fragments.
261 * If maxfrag is -1, accept all fragments without limitation.
262 */
263 if (ip6_maxfragpackets < 0)
264 ;
265 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
266 goto dropfrag;
267 frag6_nfragpackets++;
268 q6 = (struct ip6q *)kmalloc(sizeof(struct ip6q), M_FTABLE,
269 M_NOWAIT | M_ZERO);
270 if (q6 == NULL)
271 goto dropfrag;
272
273 frag6_insque(q6, &ip6q);
274
275 /* ip6q_nxt will be filled afterwards, from 1st fragment */
276 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
277 #ifdef notyet
278 q6->ip6q_nxtp = (u_char *)nxtp;
279 #endif
280 q6->ip6q_ident = ip6f->ip6f_ident;
281 q6->ip6q_arrive = 0; /* Is it used anywhere? */
282 q6->ip6q_ttl = IPV6_FRAGTTL;
283 q6->ip6q_src = ip6->ip6_src;
284 q6->ip6q_dst = ip6->ip6_dst;
285 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
286 q6->ip6q_nfrag = 0;
287 }
288
289 /*
290 * If it's the 1st fragment, record the length of the
291 * unfragmentable part and the next header of the fragment header.
292 */
293 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
294 if (fragoff == 0) {
295 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr)
296 - sizeof(struct ip6_frag);
297 q6->ip6q_nxt = ip6f->ip6f_nxt;
298 }
299
300 /*
301 * Check that the reassembled packet would not exceed 65535 bytes
302 * in size.
303 * If it would exceed, discard the fragment and return an ICMP error.
304 */
305 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
306 if (q6->ip6q_unfrglen >= 0) {
307 /* The 1st fragment has already arrived. */
308 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
309 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
310 offset - sizeof(struct ip6_frag) +
311 offsetof(struct ip6_frag, ip6f_offlg));
312 frag6_doing_reass = 0;
313 return (IPPROTO_DONE);
314 }
315 }
316 else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
317 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
318 offset - sizeof(struct ip6_frag) +
319 offsetof(struct ip6_frag, ip6f_offlg));
320 frag6_doing_reass = 0;
321 return (IPPROTO_DONE);
322 }
323 /*
324 * If it's the first fragment, do the above check for each
325 * fragment already stored in the reassembly queue.
326 */
327 if (fragoff == 0) {
328 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
329 af6 = af6dwn) {
330 af6dwn = af6->ip6af_down;
331
332 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
333 IPV6_MAXPACKET) {
334 struct mbuf *merr = IP6_REASS_MBUF(af6);
335 struct ip6_hdr *ip6err;
336 int erroff = af6->ip6af_offset;
337
338 /* dequeue the fragment. */
339 frag6_deq(af6);
340 kfree(af6, M_FTABLE);
341
342 /* adjust pointer. */
343 ip6err = mtod(merr, struct ip6_hdr *);
344
345 /*
346 * Restore source and destination addresses
347 * in the erroneous IPv6 header.
348 */
349 ip6err->ip6_src = q6->ip6q_src;
350 ip6err->ip6_dst = q6->ip6q_dst;
351
352 icmp6_error(merr, ICMP6_PARAM_PROB,
353 ICMP6_PARAMPROB_HEADER,
354 erroff - sizeof(struct ip6_frag) +
355 offsetof(struct ip6_frag, ip6f_offlg));
356 }
357 }
358 }
359
360 ip6af = (struct ip6asfrag *)kmalloc(sizeof(struct ip6asfrag), M_FTABLE,
361 M_NOWAIT | M_ZERO);
362 if (ip6af == NULL)
363 goto dropfrag;
364 ip6af->ip6af_head = ip6->ip6_flow;
365 ip6af->ip6af_len = ip6->ip6_plen;
366 ip6af->ip6af_nxt = ip6->ip6_nxt;
367 ip6af->ip6af_hlim = ip6->ip6_hlim;
368 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
369 ip6af->ip6af_off = fragoff;
370 ip6af->ip6af_frglen = frgpartlen;
371 ip6af->ip6af_offset = offset;
372 IP6_REASS_MBUF(ip6af) = m;
373
374 if (first_frag) {
375 af6 = (struct ip6asfrag *)q6;
376 goto insert;
377 }
378
379 /*
380 * Find a segment which begins after this one does.
381 */
382 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
383 af6 = af6->ip6af_down)
384 if (af6->ip6af_off > ip6af->ip6af_off)
385 break;
386
387 /*
388 * RFC 5722: Drop overlapping fragments
389 */
390 if (af6->ip6af_up != (struct ip6asfrag *)q6) {
391 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
392 - ip6af->ip6af_off;
393 if (i > 0) {
394 kfree(ip6af, M_FTABLE);
395 goto dropfrag;
396 }
397 }
398 if (af6 != (struct ip6asfrag *)q6) {
399 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
400 if (i > 0) {
401 kfree(ip6af, M_FTABLE);
402 goto dropfrag;
403 }
404 }
405
406 insert:
407
408 /*
409 * Stick new segment in its place;
410 * check for complete reassembly.
411 * Move to front of packet queue, as we are
412 * the most recently active fragmented packet.
413 */
414 frag6_enq(ip6af, af6->ip6af_up);
415 frag6_nfrags++;
416 q6->ip6q_nfrag++;
417 #if 0 /* xxx */
418 if (q6 != ip6q.ip6q_next) {
419 frag6_remque(q6);
420 frag6_insque(q6, &ip6q);
421 }
422 #endif
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 frag6_doing_reass = 0;
428 return IPPROTO_DONE;
429 }
430 next += af6->ip6af_frglen;
431 }
432 if (af6->ip6af_up->ip6af_mff) {
433 frag6_doing_reass = 0;
434 return IPPROTO_DONE;
435 }
436
437 /*
438 * Reassembly is complete; concatenate fragments.
439 */
440 ip6af = q6->ip6q_down;
441 t = m = IP6_REASS_MBUF(ip6af);
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 = IP6_REASS_MBUF(af6);
450 m_adj(t->m_next, af6->ip6af_offset);
451 kfree(af6, M_FTABLE);
452 af6 = af6dwn;
453 }
454
455 /* adjust offset to point where the original next header starts */
456 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
457 kfree(ip6af, M_FTABLE);
458
459 /*
460 * Make sure completed packet does not overflow the max packet length.
461 */
462 if ((u_int)next + (u_int)offset - sizeof(struct ip6_hdr) >
463 IPV6_MAXPACKET)
464 {
465 frag6_freef(q6);
466 goto dropfrag;
467 }
468
469 ip6 = mtod(m, struct ip6_hdr *);
470 ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr));
471 ip6->ip6_src = q6->ip6q_src;
472 ip6->ip6_dst = q6->ip6q_dst;
473 nxt = q6->ip6q_nxt;
474 #ifdef notyet
475 *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
476 #endif
477
478 /*
479 * Delete frag6 header with as a few cost as possible.
480 */
481 if (offset < m->m_len) {
482 bcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
483 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_NOWAIT)) == NULL) {
489 frag6_remque(q6);
490 frag6_nfrags -= q6->ip6q_nfrag;
491 kfree(q6, M_FTABLE);
492 frag6_nfragpackets--;
493 goto dropfrag;
494 }
495 m_adj(t, sizeof(struct ip6_frag));
496 m_cat(m, t);
497 }
498
499 /*
500 * Store NXT to the original.
501 */
502 {
503 char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
504 *prvnxtp = nxt;
505 }
506
507 frag6_remque(q6);
508 frag6_nfrags -= q6->ip6q_nfrag;
509 kfree(q6, M_FTABLE);
510 frag6_nfragpackets--;
511
512 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
513 int plen = 0;
514 for (t = m; t; t = t->m_next)
515 plen += t->m_len;
516 m->m_pkthdr.len = plen;
517 }
518
519 ip6stat.ip6s_reassembled++;
520 in6_ifstat_inc(dstifp, ifs6_reass_ok);
521
522 /*
523 * Reassembly complete, return the next protocol.
524 * Be sure to clear M_HASH to force the packet
525 * to be re-characterized.
526 */
527 m->m_flags &= ~M_HASH;
528
529 *mp = m;
530 *offp = offset;
531
532 frag6_doing_reass = 0;
533 return nxt;
534
535 dropfrag:
536 in6_ifstat_inc(dstifp, ifs6_reass_fail);
537 ip6stat.ip6s_fragdropped++;
538 m_freem(m);
539 frag6_doing_reass = 0;
540 return IPPROTO_DONE;
541 }
542
543 /*
544 * Free a fragment reassembly header and all
545 * associated datagrams.
546 */
547 static void
frag6_freef(struct ip6q * q6)548 frag6_freef(struct ip6q *q6)
549 {
550 struct ip6asfrag *af6, *down6;
551
552 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
553 af6 = down6) {
554 struct mbuf *m = IP6_REASS_MBUF(af6);
555
556 down6 = af6->ip6af_down;
557 frag6_deq(af6);
558
559 /*
560 * Return ICMP time exceeded error for the 1st fragment.
561 * Just free other fragments.
562 */
563 if (af6->ip6af_off == 0) {
564 struct ip6_hdr *ip6;
565
566 /* adjust pointer */
567 ip6 = mtod(m, struct ip6_hdr *);
568
569 /* restoure source and destination addresses */
570 ip6->ip6_src = q6->ip6q_src;
571 ip6->ip6_dst = q6->ip6q_dst;
572
573 icmp6_error(m, ICMP6_TIME_EXCEEDED,
574 ICMP6_TIME_EXCEED_REASSEMBLY, 0);
575 } else
576 m_freem(m);
577 kfree(af6, M_FTABLE);
578 }
579 frag6_remque(q6);
580 frag6_nfrags -= q6->ip6q_nfrag;
581 kfree(q6, M_FTABLE);
582 frag6_nfragpackets--;
583 }
584
585 /*
586 * Put an ip fragment on a reassembly chain.
587 * Like insque, but pointers in middle of structure.
588 */
589 static void
frag6_enq(struct ip6asfrag * af6,struct ip6asfrag * up6)590 frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6)
591 {
592 af6->ip6af_up = up6;
593 af6->ip6af_down = up6->ip6af_down;
594 up6->ip6af_down->ip6af_up = af6;
595 up6->ip6af_down = af6;
596 }
597
598 /*
599 * To frag6_enq as remque is to insque.
600 */
601 static void
frag6_deq(struct ip6asfrag * af6)602 frag6_deq(struct ip6asfrag *af6)
603 {
604 af6->ip6af_up->ip6af_down = af6->ip6af_down;
605 af6->ip6af_down->ip6af_up = af6->ip6af_up;
606 }
607
608 static void
frag6_insque(struct ip6q * new,struct ip6q * old)609 frag6_insque(struct ip6q *new, struct ip6q *old)
610 {
611 new->ip6q_prev = old;
612 new->ip6q_next = old->ip6q_next;
613 old->ip6q_next->ip6q_prev= new;
614 old->ip6q_next = new;
615 }
616
617 static void
frag6_remque(struct ip6q * p6)618 frag6_remque(struct ip6q *p6)
619 {
620 p6->ip6q_prev->ip6q_next = p6->ip6q_next;
621 p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
622 }
623
624 /*
625 * IPv6 reassembling timer processing;
626 * if a timer expires on a reassembly
627 * queue, discard it.
628 */
629 static void
frag6_slowtimo_dispatch(netmsg_t nmsg)630 frag6_slowtimo_dispatch(netmsg_t nmsg)
631 {
632 struct ip6q *q6;
633
634 ASSERT_NETISR0;
635
636 /* Reply ASAP. */
637 crit_enter();
638 netisr_replymsg(&nmsg->base, 0);
639 crit_exit();
640
641 frag6_doing_reass = 1;
642 q6 = ip6q.ip6q_next;
643 if (q6)
644 while (q6 != &ip6q) {
645 --q6->ip6q_ttl;
646 q6 = q6->ip6q_next;
647 if (q6->ip6q_prev->ip6q_ttl == 0) {
648 ip6stat.ip6s_fragtimeout++;
649 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
650 frag6_freef(q6->ip6q_prev);
651 }
652 }
653 /*
654 * If we are over the maximum number of fragments
655 * (due to the limit being lowered), drain off
656 * enough to get down to the new limit.
657 */
658 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
659 ip6q.ip6q_prev) {
660 ip6stat.ip6s_fragoverflow++;
661 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
662 frag6_freef(ip6q.ip6q_prev);
663 }
664 frag6_doing_reass = 0;
665
666 #if 0
667 /*
668 * Routing changes might produce a better route than we last used;
669 * make sure we notice eventually, even if forwarding only for one
670 * destination and the cache is never replaced.
671 */
672 if (ip6_forward_rt.ro_rt) {
673 RTFREE(ip6_forward_rt.ro_rt);
674 ip6_forward_rt.ro_rt = NULL;
675 }
676 if (ipsrcchk_rt.ro_rt) {
677 RTFREE(ipsrcchk_rt.ro_rt);
678 ipsrcchk_rt.ro_rt = NULL;
679 }
680 #endif
681 callout_reset(&frag6_slowtimo_ch, FRAG6_SLOWTIMO, frag6_slowtimo, NULL);
682 }
683
684 static void
frag6_slowtimo(void * dummy __unused)685 frag6_slowtimo(void *dummy __unused)
686 {
687 struct netmsg_base *nmsg = &frag6_slowtimo_nmsg;
688
689 KKASSERT(mycpuid == 0);
690
691 crit_enter();
692 if (nmsg->lmsg.ms_flags & MSGF_DONE)
693 netisr_sendmsg_oncpu(nmsg);
694 crit_exit();
695 }
696
697 /*
698 * Drain off all datagram fragments.
699 */
700 static void
frag6_drain_oncpu(void)701 frag6_drain_oncpu(void)
702 {
703
704 ASSERT_NETISR0;
705
706 if (frag6_doing_reass)
707 return;
708 while (ip6q.ip6q_next != &ip6q) {
709 ip6stat.ip6s_fragdropped++;
710 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
711 frag6_freef(ip6q.ip6q_next);
712 }
713 }
714
715 static void
frag6_drain_dispatch(netmsg_t nmsg)716 frag6_drain_dispatch(netmsg_t nmsg)
717 {
718
719 ASSERT_NETISR0;
720
721 crit_enter();
722 netisr_replymsg(&nmsg->base, 0);
723 crit_exit();
724
725 frag6_drain_oncpu();
726 frag6_draining = 0;
727 }
728
729 static void
frag6_drain_ipi(void * dummy __unused)730 frag6_drain_ipi(void *dummy __unused)
731 {
732 struct netmsg_base *nmsg = &frag6_drain_nmsg;
733
734 KKASSERT(mycpuid == 0);
735
736 crit_enter();
737 if (nmsg->lmsg.ms_flags & MSGF_DONE)
738 netisr_sendmsg_oncpu(nmsg);
739 crit_exit();
740 }
741
742 void
frag6_drain(void)743 frag6_drain(void)
744 {
745
746 if (IN_NETISR(0)) {
747 frag6_drain_oncpu();
748 return;
749 }
750
751 if (!frag6_nfrags || frag6_draining) {
752 /* No fragments or is draining; done. */
753 return;
754 }
755 frag6_draining = 1;
756
757 /* Target cpu0. */
758 lwkt_send_ipiq_bycpu(0, frag6_drain_ipi, NULL);
759 }
760