![[BACK]](/icons/back.gif){kind=icon}
Return to frag6.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / sys / netinet6|
Return to frag6.c CVS log | Up to [local] / sys / netinet6 |
1.1 nbrk 1: /* $OpenBSD: frag6.c,v 1.24 2007/05/01 03:38:45 ray 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/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 <dev/rndvar.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(struct ip6asfrag *, struct ip6asfrag *);
66: static void frag6_deq(struct ip6asfrag *);
67: static void frag6_insque(struct ip6q *, struct ip6q *);
68: static void frag6_remque(struct ip6q *);
69: static void frag6_freef(struct ip6q *);
70:
71: static int ip6q_locked;
72: u_int frag6_nfragpackets;
73: u_int frag6_nfrags;
74: struct ip6q ip6q; /* ip6 reassemble queue */
75:
76: static __inline int ip6q_lock_try(void);
77: static __inline void ip6q_unlock(void);
78:
79: static __inline int
80: ip6q_lock_try()
81: {
82: int s;
83:
84: /* Use splvm() due to mbuf allocation. */
85: s = splvm();
86: if (ip6q_locked) {
87: splx(s);
88: return (0);
89: }
90: ip6q_locked = 1;
91: splx(s);
92: return (1);
93: }
94:
95: static __inline void
96: ip6q_unlock()
97: {
98: int s;
99:
100: s = splvm();
101: ip6q_locked = 0;
102: splx(s);
103: }
104:
105: #ifdef DIAGNOSTIC
106: #define IP6Q_LOCK() \
107: do { \
108: if (ip6q_lock_try() == 0) { \
109: printf("%s:%d: ip6q already locked\n", __FILE__, __LINE__); \
110: panic("ip6q_lock"); \
111: } \
112: } while (0)
113: #define IP6Q_LOCK_CHECK() \
114: do { \
115: if (ip6q_locked == 0) { \
116: printf("%s:%d: ip6q lock not held\n", __FILE__, __LINE__); \
117: panic("ip6q lock check"); \
118: } \
119: } while (0)
120: #else
121: #define IP6Q_LOCK() (void) ip6q_lock_try()
122: #define IP6Q_LOCK_CHECK() /* nothing */
123: #endif
124:
125: #define IP6Q_UNLOCK() ip6q_unlock()
126:
127: #ifndef offsetof /* XXX */
128: #define offsetof(type, member) ((size_t)(&((type *)0)->member))
129: #endif
130:
131: /*
132: * Initialise reassembly queue and fragment identifier.
133: */
134: void
135: frag6_init()
136: {
137:
138: ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
139: }
140:
141: /*
142: * In RFC2460, fragment and reassembly rule do not agree with each other,
143: * in terms of next header field handling in fragment header.
144: * While the sender will use the same value for all of the fragmented packets,
145: * receiver is suggested not to check the consistency.
146: *
147: * fragment rule (p20):
148: * (2) A Fragment header containing:
149: * The Next Header value that identifies the first header of
150: * the Fragmentable Part of the original packet.
151: * -> next header field is same for all fragments
152: *
153: * reassembly rule (p21):
154: * The Next Header field of the last header of the Unfragmentable
155: * Part is obtained from the Next Header field of the first
156: * fragment's Fragment header.
157: * -> should grab it from the first fragment only
158: *
159: * The following note also contradicts with fragment rule - noone is going to
160: * send different fragment with different next header field.
161: *
162: * additional note (p22):
163: * The Next Header values in the Fragment headers of different
164: * fragments of the same original packet may differ. Only the value
165: * from the Offset zero fragment packet is used for reassembly.
166: * -> should grab it from the first fragment only
167: *
168: * There is no explicit reason given in the RFC. Historical reason maybe?
169: */
170: /*
171: * Fragment input
172: */
173: int
174: frag6_input(mp, offp, proto)
175: struct mbuf **mp;
176: int *offp, proto;
177: {
178: struct mbuf *m = *mp, *t;
179: struct ip6_hdr *ip6;
180: struct ip6_frag *ip6f;
181: struct ip6q *q6;
182: struct ip6asfrag *af6, *ip6af, *af6dwn;
183: int offset = *offp, nxt, i, next;
184: int first_frag = 0;
185: int fragoff, frgpartlen; /* must be larger than u_int16_t */
186: struct ifnet *dstifp;
187: #ifdef IN6_IFSTAT_STRICT
188: static struct route_in6 ro;
189: struct sockaddr_in6 *dst;
190: #endif
191: u_int8_t ecn, ecn0;
192:
193: ip6 = mtod(m, struct ip6_hdr *);
194: IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
195: if (ip6f == NULL)
196: return IPPROTO_DONE;
197:
198: dstifp = NULL;
199: #ifdef IN6_IFSTAT_STRICT
200: /* find the destination interface of the packet. */
201: dst = (struct sockaddr_in6 *)&ro.ro_dst;
202: if (ro.ro_rt
203: && ((ro.ro_rt->rt_flags & RTF_UP) == 0
204: || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
205: RTFREE(ro.ro_rt);
206: ro.ro_rt = (struct rtentry *)0;
207: }
208: if (ro.ro_rt == NULL) {
209: bzero(dst, sizeof(*dst));
210: dst->sin6_family = AF_INET6;
211: dst->sin6_len = sizeof(struct sockaddr_in6);
212: dst->sin6_addr = ip6->ip6_dst;
213: }
214:
215: rtalloc_mpath((struct route *)&ro, &ip6->ip6_src.s6_addr32[0], 0);
216:
217: if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
218: dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
219: #else
220: /* we are violating the spec, this is not the destination interface */
221: if ((m->m_flags & M_PKTHDR) != 0)
222: dstifp = m->m_pkthdr.rcvif;
223: #endif
224:
225: /* jumbo payload can't contain a fragment header */
226: if (ip6->ip6_plen == 0) {
227: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
228: in6_ifstat_inc(dstifp, ifs6_reass_fail);
229: return IPPROTO_DONE;
230: }
231:
232: /*
233: * check whether fragment packet's fragment length is
234: * multiple of 8 octets.
235: * sizeof(struct ip6_frag) == 8
236: * sizeof(struct ip6_hdr) = 40
237: */
238: if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
239: (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
240: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
241: offsetof(struct ip6_hdr, ip6_plen));
242: in6_ifstat_inc(dstifp, ifs6_reass_fail);
243: return IPPROTO_DONE;
244: }
245:
246: ip6stat.ip6s_fragments++;
247: in6_ifstat_inc(dstifp, ifs6_reass_reqd);
248:
249: /* offset now points to data portion */
250: offset += sizeof(struct ip6_frag);
251:
252: IP6Q_LOCK();
253:
254: /*
255: * Enforce upper bound on number of fragments.
256: * If maxfrag is 0, never accept fragments.
257: * If maxfrag is -1, accept all fragments without limitation.
258: */
259: if (ip6_maxfrags < 0)
260: ;
261: else if (frag6_nfrags >= (u_int)ip6_maxfrags)
262: goto dropfrag;
263:
264: for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
265: if (ip6f->ip6f_ident == q6->ip6q_ident &&
266: IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
267: IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
268: break;
269:
270: if (q6 == &ip6q) {
271: /*
272: * the first fragment to arrive, create a reassembly queue.
273: */
274: first_frag = 1;
275:
276: /*
277: * Enforce upper bound on number of fragmented packets
278: * for which we attempt reassembly;
279: * If maxfragpackets is 0, never accept fragments.
280: * If maxfragpackets is -1, accept all fragments without
281: * limitation.
282: */
283: if (ip6_maxfragpackets < 0)
284: ;
285: else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
286: goto dropfrag;
287: frag6_nfragpackets++;
288: q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
289: M_DONTWAIT);
290: if (q6 == NULL)
291: goto dropfrag;
292: bzero(q6, sizeof(*q6));
293:
294: frag6_insque(q6, &ip6q);
295:
296: /* ip6q_nxt will be filled afterwards, from 1st fragment */
297: q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
298: #ifdef notyet
299: q6->ip6q_nxtp = (u_char *)nxtp;
300: #endif
301: q6->ip6q_ident = ip6f->ip6f_ident;
302: q6->ip6q_arrive = 0; /* Is it used anywhere? */
303: q6->ip6q_ttl = IPV6_FRAGTTL;
304: q6->ip6q_src = ip6->ip6_src;
305: q6->ip6q_dst = ip6->ip6_dst;
306: q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
307:
308: q6->ip6q_nfrag = 0;
309: }
310:
311: /*
312: * If it's the 1st fragment, record the length of the
313: * unfragmentable part and the next header of the fragment header.
314: */
315: fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
316: if (fragoff == 0) {
317: q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
318: sizeof(struct ip6_frag);
319: q6->ip6q_nxt = ip6f->ip6f_nxt;
320: }
321:
322: /*
323: * Check that the reassembled packet would not exceed 65535 bytes
324: * in size.
325: * If it would exceed, discard the fragment and return an ICMP error.
326: */
327: frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
328: if (q6->ip6q_unfrglen >= 0) {
329: /* The 1st fragment has already arrived. */
330: if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
331: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
332: offset - sizeof(struct ip6_frag) +
333: offsetof(struct ip6_frag, ip6f_offlg));
334: IP6Q_UNLOCK();
335: return (IPPROTO_DONE);
336: }
337: } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
338: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
339: offset - sizeof(struct ip6_frag) +
340: offsetof(struct ip6_frag, ip6f_offlg));
341: IP6Q_UNLOCK();
342: return (IPPROTO_DONE);
343: }
344: /*
345: * If it's the first fragment, do the above check for each
346: * fragment already stored in the reassembly queue.
347: */
348: if (fragoff == 0) {
349: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
350: af6 = af6dwn) {
351: af6dwn = af6->ip6af_down;
352:
353: if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
354: IPV6_MAXPACKET) {
355: struct mbuf *merr = IP6_REASS_MBUF(af6);
356: struct ip6_hdr *ip6err;
357: int erroff = af6->ip6af_offset;
358:
359: /* dequeue the fragment. */
360: frag6_deq(af6);
361: free(af6, M_FTABLE);
362:
363: /* adjust pointer. */
364: ip6err = mtod(merr, struct ip6_hdr *);
365:
366: /*
367: * Restore source and destination addresses
368: * in the erroneous IPv6 header.
369: */
370: ip6err->ip6_src = q6->ip6q_src;
371: ip6err->ip6_dst = q6->ip6q_dst;
372:
373: icmp6_error(merr, ICMP6_PARAM_PROB,
374: ICMP6_PARAMPROB_HEADER,
375: erroff - sizeof(struct ip6_frag) +
376: offsetof(struct ip6_frag, ip6f_offlg));
377: }
378: }
379: }
380:
381: ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
382: M_DONTWAIT);
383: if (ip6af == NULL)
384: goto dropfrag;
385: bzero(ip6af, sizeof(*ip6af));
386: ip6af->ip6af_head = ip6->ip6_flow;
387: ip6af->ip6af_len = ip6->ip6_plen;
388: ip6af->ip6af_nxt = ip6->ip6_nxt;
389: ip6af->ip6af_hlim = ip6->ip6_hlim;
390: ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
391: ip6af->ip6af_off = fragoff;
392: ip6af->ip6af_frglen = frgpartlen;
393: ip6af->ip6af_offset = offset;
394: IP6_REASS_MBUF(ip6af) = m;
395:
396: if (first_frag) {
397: af6 = (struct ip6asfrag *)q6;
398: goto insert;
399: }
400:
401: /*
402: * Handle ECN by comparing this segment with the first one;
403: * if CE is set, do not lose CE.
404: * drop if CE and not-ECT are mixed for the same packet.
405: */
406: ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
407: ecn0 = (ntohl(q6->ip6q_down->ip6af_head) >> 20) & IPTOS_ECN_MASK;
408: if (ecn == IPTOS_ECN_CE) {
409: if (ecn0 == IPTOS_ECN_NOTECT) {
410: free(ip6af, M_FTABLE);
411: goto dropfrag;
412: }
413: if (ecn0 != IPTOS_ECN_CE)
414: q6->ip6q_down->ip6af_head |= htonl(IPTOS_ECN_CE << 20);
415: }
416: if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) {
417: free(ip6af, M_FTABLE);
418: goto dropfrag;
419: }
420:
421: /*
422: * Find a segment which begins after this one does.
423: */
424: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
425: af6 = af6->ip6af_down)
426: if (af6->ip6af_off > ip6af->ip6af_off)
427: break;
428:
429: #if 0
430: /*
431: * If there is a preceding segment, it may provide some of
432: * our data already. If so, drop the data from the incoming
433: * segment. If it provides all of our data, drop us.
434: */
435: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
436: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
437: - ip6af->ip6af_off;
438: if (i > 0) {
439: if (i >= ip6af->ip6af_frglen)
440: goto dropfrag;
441: m_adj(IP6_REASS_MBUF(ip6af), i);
442: ip6af->ip6af_off += i;
443: ip6af->ip6af_frglen -= i;
444: }
445: }
446:
447: /*
448: * While we overlap succeeding segments trim them or,
449: * if they are completely covered, dequeue them.
450: */
451: while (af6 != (struct ip6asfrag *)q6 &&
452: ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
453: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
454: if (i < af6->ip6af_frglen) {
455: af6->ip6af_frglen -= i;
456: af6->ip6af_off += i;
457: m_adj(IP6_REASS_MBUF(af6), i);
458: break;
459: }
460: af6 = af6->ip6af_down;
461: m_freem(IP6_REASS_MBUF(af6->ip6af_up));
462: frag6_deq(af6->ip6af_up);
463: }
464: #else
465: /*
466: * If the incoming fragment overlaps some existing fragments in
467: * the reassembly queue, drop it, since it is dangerous to override
468: * existing fragments from a security point of view.
469: * We don't know which fragment is the bad guy - here we trust
470: * fragment that came in earlier, with no real reason.
471: */
472: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
473: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
474: - ip6af->ip6af_off;
475: if (i > 0) {
476: #if 0 /* suppress the noisy log */
477: log(LOG_ERR, "%d bytes of a fragment from %s "
478: "overlaps the previous fragment\n",
479: i, ip6_sprintf(&q6->ip6q_src));
480: #endif
481: free(ip6af, M_FTABLE);
482: goto dropfrag;
483: }
484: }
485: if (af6 != (struct ip6asfrag *)q6) {
486: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
487: if (i > 0) {
488: #if 0 /* suppress the noisy log */
489: log(LOG_ERR, "%d bytes of a fragment from %s "
490: "overlaps the succeeding fragment",
491: i, ip6_sprintf(&q6->ip6q_src));
492: #endif
493: free(ip6af, M_FTABLE);
494: goto dropfrag;
495: }
496: }
497: #endif
498:
499: insert:
500:
501: /*
502: * Stick new segment in its place;
503: * check for complete reassembly.
504: * Move to front of packet queue, as we are
505: * the most recently active fragmented packet.
506: */
507: frag6_enq(ip6af, af6->ip6af_up);
508: frag6_nfrags++;
509: q6->ip6q_nfrag++;
510: #if 0 /* xxx */
511: if (q6 != ip6q.ip6q_next) {
512: frag6_remque(q6);
513: frag6_insque(q6, &ip6q);
514: }
515: #endif
516: next = 0;
517: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
518: af6 = af6->ip6af_down) {
519: if (af6->ip6af_off != next) {
520: IP6Q_UNLOCK();
521: return IPPROTO_DONE;
522: }
523: next += af6->ip6af_frglen;
524: }
525: if (af6->ip6af_up->ip6af_mff) {
526: IP6Q_UNLOCK();
527: return IPPROTO_DONE;
528: }
529:
530: /*
531: * Reassembly is complete; concatenate fragments.
532: */
533: ip6af = q6->ip6q_down;
534: t = m = IP6_REASS_MBUF(ip6af);
535: af6 = ip6af->ip6af_down;
536: frag6_deq(ip6af);
537: while (af6 != (struct ip6asfrag *)q6) {
538: af6dwn = af6->ip6af_down;
539: frag6_deq(af6);
540: while (t->m_next)
541: t = t->m_next;
542: t->m_next = IP6_REASS_MBUF(af6);
543: m_adj(t->m_next, af6->ip6af_offset);
544: free(af6, M_FTABLE);
545: af6 = af6dwn;
546: }
547:
548: /* adjust offset to point where the original next header starts */
549: offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
550: free(ip6af, M_FTABLE);
551: ip6 = mtod(m, struct ip6_hdr *);
552: ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr));
553: ip6->ip6_src = q6->ip6q_src;
554: ip6->ip6_dst = q6->ip6q_dst;
555: nxt = q6->ip6q_nxt;
556: #ifdef notyet
557: *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
558: #endif
559:
560: /*
561: * Delete frag6 header with as a few cost as possible.
562: */
563: if (offset < m->m_len) {
564: ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
565: offset);
566: m->m_data += sizeof(struct ip6_frag);
567: m->m_len -= sizeof(struct ip6_frag);
568: } else {
569: /* this comes with no copy if the boundary is on cluster */
570: if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
571: frag6_remque(q6);
572: frag6_nfrags -= q6->ip6q_nfrag;
573: free(q6, M_FTABLE);
574: frag6_nfragpackets--;
575: goto dropfrag;
576: }
577: m_adj(t, sizeof(struct ip6_frag));
578: m_cat(m, t);
579: }
580:
581: /*
582: * Store NXT to the original.
583: */
584: {
585: u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
586: *prvnxtp = nxt;
587: }
588:
589: frag6_remque(q6);
590: frag6_nfrags -= q6->ip6q_nfrag;
591: free(q6, M_FTABLE);
592: frag6_nfragpackets--;
593:
594: if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
595: int plen = 0;
596: for (t = m; t; t = t->m_next)
597: plen += t->m_len;
598: m->m_pkthdr.len = plen;
599: }
600:
601: ip6stat.ip6s_reassembled++;
602: in6_ifstat_inc(dstifp, ifs6_reass_ok);
603:
604: /*
605: * Tell launch routine the next header
606: */
607:
608: *mp = m;
609: *offp = offset;
610:
611: IP6Q_UNLOCK();
612: return nxt;
613:
614: dropfrag:
615: in6_ifstat_inc(dstifp, ifs6_reass_fail);
616: ip6stat.ip6s_fragdropped++;
617: m_freem(m);
618: IP6Q_UNLOCK();
619: return IPPROTO_DONE;
620: }
621:
622: /*
623: * Free a fragment reassembly header and all
624: * associated datagrams.
625: */
626: void
627: frag6_freef(q6)
628: struct ip6q *q6;
629: {
630: struct ip6asfrag *af6, *down6;
631:
632: IP6Q_LOCK_CHECK();
633:
634: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
635: af6 = down6) {
636: struct mbuf *m = IP6_REASS_MBUF(af6);
637:
638: down6 = af6->ip6af_down;
639: frag6_deq(af6);
640:
641: /*
642: * Return ICMP time exceeded error for the 1st fragment.
643: * Just free other fragments.
644: */
645: if (af6->ip6af_off == 0) {
646: struct ip6_hdr *ip6;
647:
648: /* adjust pointer */
649: ip6 = mtod(m, struct ip6_hdr *);
650:
651: /* restoure source and destination addresses */
652: ip6->ip6_src = q6->ip6q_src;
653: ip6->ip6_dst = q6->ip6q_dst;
654:
655: icmp6_error(m, ICMP6_TIME_EXCEEDED,
656: ICMP6_TIME_EXCEED_REASSEMBLY, 0);
657: } else
658: m_freem(m);
659: free(af6, M_FTABLE);
660: }
661: frag6_remque(q6);
662: frag6_nfrags -= q6->ip6q_nfrag;
663: free(q6, M_FTABLE);
664: frag6_nfragpackets--;
665: }
666:
667: /*
668: * Put an ip fragment on a reassembly chain.
669: * Like insque, but pointers in middle of structure.
670: */
671: void
672: frag6_enq(af6, up6)
673: struct ip6asfrag *af6, *up6;
674: {
675:
676: IP6Q_LOCK_CHECK();
677:
678: af6->ip6af_up = up6;
679: af6->ip6af_down = up6->ip6af_down;
680: up6->ip6af_down->ip6af_up = af6;
681: up6->ip6af_down = af6;
682: }
683:
684: /*
685: * To frag6_enq as remque is to insque.
686: */
687: void
688: frag6_deq(af6)
689: struct ip6asfrag *af6;
690: {
691:
692: IP6Q_LOCK_CHECK();
693:
694: af6->ip6af_up->ip6af_down = af6->ip6af_down;
695: af6->ip6af_down->ip6af_up = af6->ip6af_up;
696: }
697:
698: void
699: frag6_insque(new, old)
700: struct ip6q *new, *old;
701: {
702:
703: IP6Q_LOCK_CHECK();
704:
705: new->ip6q_prev = old;
706: new->ip6q_next = old->ip6q_next;
707: old->ip6q_next->ip6q_prev= new;
708: old->ip6q_next = new;
709: }
710:
711: void
712: frag6_remque(p6)
713: struct ip6q *p6;
714: {
715:
716: IP6Q_LOCK_CHECK();
717:
718: p6->ip6q_prev->ip6q_next = p6->ip6q_next;
719: p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
720: }
721:
722: /*
723: * IPv6 reassembling timer processing;
724: * if a timer expires on a reassembly
725: * queue, discard it.
726: */
727: void
728: frag6_slowtimo()
729: {
730: struct ip6q *q6;
731: int s = splsoftnet();
732:
733: IP6Q_LOCK();
734: q6 = ip6q.ip6q_next;
735: if (q6)
736: while (q6 != &ip6q) {
737: --q6->ip6q_ttl;
738: q6 = q6->ip6q_next;
739: if (q6->ip6q_prev->ip6q_ttl == 0) {
740: ip6stat.ip6s_fragtimeout++;
741: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
742: frag6_freef(q6->ip6q_prev);
743: }
744: }
745: /*
746: * If we are over the maximum number of fragments
747: * (due to the limit being lowered), drain off
748: * enough to get down to the new limit.
749: */
750: while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
751: ip6q.ip6q_prev) {
752: ip6stat.ip6s_fragoverflow++;
753: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
754: frag6_freef(ip6q.ip6q_prev);
755: }
756: IP6Q_UNLOCK();
757:
758: #if 0
759: /*
760: * Routing changes might produce a better route than we last used;
761: * make sure we notice eventually, even if forwarding only for one
762: * destination and the cache is never replaced.
763: */
764: if (ip6_forward_rt.ro_rt) {
765: RTFREE(ip6_forward_rt.ro_rt);
766: ip6_forward_rt.ro_rt = 0;
767: }
768: if (ipsrcchk_rt.ro_rt) {
769: RTFREE(ipsrcchk_rt.ro_rt);
770: ipsrcchk_rt.ro_rt = 0;
771: }
772: #endif
773:
774: splx(s);
775: }
776:
777: /*
778: * Drain off all datagram fragments.
779: */
780: void
781: frag6_drain()
782: {
783:
784: if (ip6q_lock_try() == 0)
785: return;
786: while (ip6q.ip6q_next != &ip6q) {
787: ip6stat.ip6s_fragdropped++;
788: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
789: frag6_freef(ip6q.ip6q_next);
790: }
791: IP6Q_UNLOCK();
792: }