Annotation of src/sys/netinet6/frag6.c, Revision 1.10.4.1
1.10.4.1! he 1: /* $NetBSD: frag6.c,v 1.10 2000/02/06 12:49:42 itojun Exp $ */
1.3 thorpej 2:
1.2 itojun 3: /*
4: * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. Neither the name of the project nor the names of its contributors
16: * may be used to endorse or promote products derived from this software
17: * without specific prior written permission.
18: *
19: * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22: * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29: * SUCH DAMAGE.
30: */
31:
32: #include <sys/param.h>
33: #include <sys/systm.h>
34: #include <sys/malloc.h>
35: #include <sys/mbuf.h>
36: #include <sys/domain.h>
37: #include <sys/protosw.h>
38: #include <sys/socket.h>
39: #include <sys/errno.h>
40: #include <sys/time.h>
41: #include <sys/kernel.h>
42: #include <sys/syslog.h>
43:
44: #include <net/if.h>
45: #include <net/route.h>
46:
47: #include <netinet/in.h>
48: #include <netinet/in_var.h>
1.10 itojun 49: #include <netinet/ip6.h>
1.2 itojun 50: #include <netinet6/in6_pcb.h>
51: #include <netinet6/ip6_var.h>
1.10 itojun 52: #include <netinet/icmp6.h>
1.2 itojun 53:
1.7 itojun 54: #include <net/net_osdep.h>
55:
56: /*
57: * Define it to get a correct behavior on per-interface statistics.
58: * You will need to perform an extra routing table lookup, per fragment,
59: * to do it. This may, or may not be, a performance hit.
60: */
61: #define IN6_IFSTAT_STRICT
62:
1.2 itojun 63: static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
64: static void frag6_deq __P((struct ip6asfrag *));
65: static void frag6_insque __P((struct ip6q *, struct ip6q *));
66: static void frag6_remque __P((struct ip6q *));
67: static void frag6_freef __P((struct ip6q *));
68:
1.10.4.1! he 69: /* XXX we eventually need splreass6, or some real semaphore */
1.2 itojun 70: int frag6_doing_reass;
71: u_int frag6_nfragpackets;
72: struct ip6q ip6q; /* ip6 reassemble queue */
73:
1.9 itojun 74: #ifndef offsetof /* XXX */
75: #define offsetof(type, member) ((size_t)(&((type *)0)->member))
76: #endif
77:
1.2 itojun 78: /*
79: * Initialise reassembly queue and fragment identifier.
80: */
81: void
82: frag6_init()
83: {
1.6 itojun 84: struct timeval tv;
85:
86: /*
87: * in many cases, random() here does NOT return random number
88: * as initialization during bootstrap time occur in fixed order.
89: */
90: microtime(&tv);
1.9 itojun 91: ip6_id = random() ^ tv.tv_usec;
1.2 itojun 92: ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
93: }
94:
95: /*
1.9 itojun 96: * In RFC2460, fragment and reassembly rule do not agree with each other,
97: * in terms of next header field handling in fragment header.
98: * While the sender will use the same value for all of the fragmented packets,
99: * receiver is suggested not to check the consistency.
100: *
101: * fragment rule (p20):
102: * (2) A Fragment header containing:
103: * The Next Header value that identifies the first header of
104: * the Fragmentable Part of the original packet.
105: * -> next header field is same for all fragments
106: *
107: * reassembly rule (p21):
108: * The Next Header field of the last header of the Unfragmentable
109: * Part is obtained from the Next Header field of the first
110: * fragment's Fragment header.
111: * -> should grab it from the first fragment only
112: *
113: * The following note also contradicts with fragment rule - noone is going to
114: * send different fragment with different next header field.
115: *
116: * additional note (p22):
117: * The Next Header values in the Fragment headers of different
118: * fragments of the same original packet may differ. Only the value
119: * from the Offset zero fragment packet is used for reassembly.
120: * -> should grab it from the first fragment only
121: *
122: * There is no explicit reason given in the RFC. Historical reason maybe?
123: */
124: /*
1.2 itojun 125: * Fragment input
126: */
127: int
128: frag6_input(mp, offp, proto)
129: struct mbuf **mp;
130: int *offp, proto;
131: {
132: struct mbuf *m = *mp, *t;
133: struct ip6_hdr *ip6;
134: struct ip6_frag *ip6f;
135: struct ip6q *q6;
1.9 itojun 136: struct ip6asfrag *af6, *ip6af, *af6dwn;
1.2 itojun 137: int offset = *offp, nxt, i, next;
138: int first_frag = 0;
1.9 itojun 139: int fragoff, frgpartlen; /* must be larger than u_int16_t */
1.7 itojun 140: struct ifnet *dstifp;
141: #ifdef IN6_IFSTAT_STRICT
142: static struct route_in6 ro;
143: struct sockaddr_in6 *dst;
144: #endif
1.2 itojun 145:
1.7 itojun 146: ip6 = mtod(m, struct ip6_hdr *);
147: #ifndef PULLDOWN_TEST
1.2 itojun 148: IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
1.7 itojun 149: ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
150: #else
151: IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
152: if (ip6f == NULL)
153: return IPPROTO_DONE;
154: #endif
1.2 itojun 155:
1.7 itojun 156: dstifp = NULL;
157: #ifdef IN6_IFSTAT_STRICT
158: /* find the destination interface of the packet. */
159: dst = (struct sockaddr_in6 *)&ro.ro_dst;
160: if (ro.ro_rt
161: && ((ro.ro_rt->rt_flags & RTF_UP) == 0
162: || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
163: RTFREE(ro.ro_rt);
164: ro.ro_rt = (struct rtentry *)0;
165: }
166: if (ro.ro_rt == NULL) {
167: bzero(dst, sizeof(*dst));
168: dst->sin6_family = AF_INET6;
169: dst->sin6_len = sizeof(struct sockaddr_in6);
170: dst->sin6_addr = ip6->ip6_dst;
171: }
172: rtalloc((struct route *)&ro);
173: if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
174: dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
175: #else
176: /* we are violating the spec, this is not the destination interface */
177: if ((m->m_flags & M_PKTHDR) != 0)
178: dstifp = m->m_pkthdr.rcvif;
179: #endif
1.2 itojun 180:
181: /* jumbo payload can't contain a fragment header */
182: if (ip6->ip6_plen == 0) {
183: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
1.7 itojun 184: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 185: return IPPROTO_DONE;
186: }
187:
188: /*
189: * check whether fragment packet's fragment length is
190: * multiple of 8 octets.
191: * sizeof(struct ip6_frag) == 8
192: * sizeof(struct ip6_hdr) = 40
193: */
194: if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
195: (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
196: icmp6_error(m, ICMP6_PARAM_PROB,
197: ICMP6_PARAMPROB_HEADER,
1.9 itojun 198: offsetof(struct ip6_hdr, ip6_plen));
1.7 itojun 199: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 200: return IPPROTO_DONE;
201: }
202:
203: ip6stat.ip6s_fragments++;
1.7 itojun 204: in6_ifstat_inc(dstifp, ifs6_reass_reqd);
1.2 itojun 205:
1.9 itojun 206: /* offset now points to data portion */
1.2 itojun 207: offset += sizeof(struct ip6_frag);
208:
209: for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
210: if (ip6f->ip6f_ident == q6->ip6q_ident &&
211: IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
212: IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
213: break;
214:
215: if (q6 == &ip6q) {
216: /*
217: * the first fragment to arrive, create a reassembly queue.
218: */
219: first_frag = 1;
220: frag6_nfragpackets++;
221:
222: /*
223: * Enforce upper bound on number of fragmented packets
224: * for which we attempt reassembly;
225: * If maxfrag is 0, never accept fragments.
226: * If maxfrag is -1, accept all fragments without limitation.
227: */
228: if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) {
229: ip6stat.ip6s_fragoverflow++;
1.7 itojun 230: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 231: frag6_freef(ip6q.ip6q_prev);
232: }
233: q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
234: M_DONTWAIT);
235: if (q6 == NULL)
236: goto dropfrag;
1.9 itojun 237: bzero(q6, sizeof(*q6));
1.2 itojun 238:
239: frag6_insque(q6, &ip6q);
240:
1.9 itojun 241: /* ip6q_nxt will be filled afterwards, from 1st fragment */
1.2 itojun 242: q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
243: #ifdef notyet
244: q6->ip6q_nxtp = (u_char *)nxtp;
245: #endif
246: q6->ip6q_ident = ip6f->ip6f_ident;
247: q6->ip6q_arrive = 0; /* Is it used anywhere? */
248: q6->ip6q_ttl = IPV6_FRAGTTL;
249: q6->ip6q_src = ip6->ip6_src;
250: q6->ip6q_dst = ip6->ip6_dst;
251: q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
252: }
253:
254: /*
255: * If it's the 1st fragment, record the length of the
256: * unfragmentable part and the next header of the fragment header.
257: */
258: fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
259: if (fragoff == 0) {
260: q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr)
261: - sizeof(struct ip6_frag);
262: q6->ip6q_nxt = ip6f->ip6f_nxt;
263: }
264:
265: /*
266: * Check that the reassembled packet would not exceed 65535 bytes
267: * in size.
268: * If it would exceed, discard the fragment and return an ICMP error.
269: */
1.9 itojun 270: frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
1.2 itojun 271: if (q6->ip6q_unfrglen >= 0) {
272: /* The 1st fragment has already arrived. */
273: if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
274: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
1.9 itojun 275: offset - sizeof(struct ip6_frag) +
276: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 277: return(IPPROTO_DONE);
278: }
279: }
280: else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
281: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
1.9 itojun 282: offset - sizeof(struct ip6_frag) +
283: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 284: return(IPPROTO_DONE);
285: }
286: /*
287: * If it's the first fragment, do the above check for each
288: * fragment already stored in the reassembly queue.
289: */
290: if (fragoff == 0) {
291: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
292: af6 = af6dwn) {
293: af6dwn = af6->ip6af_down;
294:
295: if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
296: IPV6_MAXPACKET) {
297: struct mbuf *merr = IP6_REASS_MBUF(af6);
298: struct ip6_hdr *ip6err;
299: int erroff = af6->ip6af_offset;
300:
301: /* dequeue the fragment. */
302: frag6_deq(af6);
1.9 itojun 303: free(af6, M_FTABLE);
1.2 itojun 304:
305: /* adjust pointer. */
306: ip6err = mtod(merr, struct ip6_hdr *);
307:
308: /*
309: * Restore source and destination addresses
310: * in the erroneous IPv6 header.
311: */
312: ip6err->ip6_src = q6->ip6q_src;
313: ip6err->ip6_dst = q6->ip6q_dst;
314:
315: icmp6_error(merr, ICMP6_PARAM_PROB,
316: ICMP6_PARAMPROB_HEADER,
1.9 itojun 317: erroff - sizeof(struct ip6_frag) +
318: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 319: }
320: }
321: }
322:
1.9 itojun 323: ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
324: M_DONTWAIT);
325: if (ip6af == NULL)
326: goto dropfrag;
327: bzero(ip6af, sizeof(*ip6af));
328: ip6af->ip6af_head = ip6->ip6_flow;
329: ip6af->ip6af_len = ip6->ip6_plen;
330: ip6af->ip6af_nxt = ip6->ip6_nxt;
331: ip6af->ip6af_hlim = ip6->ip6_hlim;
1.2 itojun 332: ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
333: ip6af->ip6af_off = fragoff;
334: ip6af->ip6af_frglen = frgpartlen;
335: ip6af->ip6af_offset = offset;
336: IP6_REASS_MBUF(ip6af) = m;
337:
338: if (first_frag) {
339: af6 = (struct ip6asfrag *)q6;
340: goto insert;
341: }
342:
343: /*
344: * Find a segment which begins after this one does.
345: */
346: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
347: af6 = af6->ip6af_down)
348: if (af6->ip6af_off > ip6af->ip6af_off)
349: break;
350:
351: #if 0
352: /*
353: * If there is a preceding segment, it may provide some of
354: * our data already. If so, drop the data from the incoming
355: * segment. If it provides all of our data, drop us.
356: */
357: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
358: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
359: - ip6af->ip6af_off;
360: if (i > 0) {
361: if (i >= ip6af->ip6af_frglen)
362: goto dropfrag;
363: m_adj(IP6_REASS_MBUF(ip6af), i);
364: ip6af->ip6af_off += i;
365: ip6af->ip6af_frglen -= i;
366: }
367: }
368:
369: /*
370: * While we overlap succeeding segments trim them or,
371: * if they are completely covered, dequeue them.
372: */
373: while (af6 != (struct ip6asfrag *)q6 &&
374: ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
375: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
376: if (i < af6->ip6af_frglen) {
377: af6->ip6af_frglen -= i;
378: af6->ip6af_off += i;
379: m_adj(IP6_REASS_MBUF(af6), i);
380: break;
381: }
382: af6 = af6->ip6af_down;
383: m_freem(IP6_REASS_MBUF(af6->ip6af_up));
384: frag6_deq(af6->ip6af_up);
385: }
386: #else
387: /*
388: * If the incoming framgent overlaps some existing fragments in
389: * the reassembly queue, drop it, since it is dangerous to override
390: * existing fragments from a security point of view.
391: */
392: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
393: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
394: - ip6af->ip6af_off;
395: if (i > 0) {
1.10.4.1! he 396: #if 0 /* suppress the noisy log */
1.2 itojun 397: log(LOG_ERR, "%d bytes of a fragment from %s "
398: "overlaps the previous fragment\n",
399: i, ip6_sprintf(&q6->ip6q_src));
1.10.4.1! he 400: #endif
! 401: free(ip6af, M_FTABLE);
1.2 itojun 402: goto dropfrag;
403: }
404: }
405: if (af6 != (struct ip6asfrag *)q6) {
406: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
407: if (i > 0) {
1.10.4.1! he 408: #if 0 /* suppress the noisy log */
1.2 itojun 409: log(LOG_ERR, "%d bytes of a fragment from %s "
410: "overlaps the succeeding fragment",
411: i, ip6_sprintf(&q6->ip6q_src));
1.10.4.1! he 412: #endif
! 413: free(ip6af, M_FTABLE);
1.2 itojun 414: goto dropfrag;
415: }
416: }
417: #endif
418:
419: insert:
420:
421: /*
422: * Stick new segment in its place;
423: * check for complete reassembly.
424: * Move to front of packet queue, as we are
425: * the most recently active fragmented packet.
426: */
427: frag6_enq(ip6af, af6->ip6af_up);
428: #if 0 /* xxx */
429: if (q6 != ip6q.ip6q_next) {
430: frag6_remque(q6);
431: frag6_insque(q6, &ip6q);
432: }
433: #endif
434: next = 0;
435: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
436: af6 = af6->ip6af_down) {
437: if (af6->ip6af_off != next) {
438: frag6_doing_reass = 0;
439: return IPPROTO_DONE;
440: }
441: next += af6->ip6af_frglen;
442: }
443: if (af6->ip6af_up->ip6af_mff) {
444: frag6_doing_reass = 0;
445: return IPPROTO_DONE;
446: }
447:
448: /*
449: * Reassembly is complete; concatenate fragments.
450: */
451: ip6af = q6->ip6q_down;
452: t = m = IP6_REASS_MBUF(ip6af);
453: af6 = ip6af->ip6af_down;
1.9 itojun 454: frag6_deq(ip6af);
1.2 itojun 455: while (af6 != (struct ip6asfrag *)q6) {
1.9 itojun 456: af6dwn = af6->ip6af_down;
457: frag6_deq(af6);
1.2 itojun 458: while (t->m_next)
459: t = t->m_next;
460: t->m_next = IP6_REASS_MBUF(af6);
1.9 itojun 461: m_adj(t->m_next, af6->ip6af_offset);
462: free(af6, M_FTABLE);
463: af6 = af6dwn;
1.2 itojun 464: }
465:
466: /* adjust offset to point where the original next header starts */
467: offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
1.9 itojun 468: free(ip6af, M_FTABLE);
469: ip6 = mtod(m, struct ip6_hdr *);
1.2 itojun 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: */
1.9 itojun 481: if (offset < m->m_len) {
1.7 itojun 482: ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
1.2 itojun 483: offset);
1.9 itojun 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_remque(q6);
490: free(q6, M_FTABLE);
491: frag6_nfragpackets--;
492: goto dropfrag;
493: }
494: m_adj(t, sizeof(struct ip6_frag));
495: m_cat(m, t);
1.2 itojun 496: }
497:
498: /*
499: * Store NXT to the original.
500: */
501: {
502: char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
503: *prvnxtp = nxt;
504: }
505:
506: frag6_remque(q6);
507: free(q6, M_FTABLE);
508: frag6_nfragpackets--;
509:
510: if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
511: int plen = 0;
512: for (t = m; t; t = t->m_next)
513: plen += t->m_len;
514: m->m_pkthdr.len = plen;
515: }
516:
517: ip6stat.ip6s_reassembled++;
1.7 itojun 518: in6_ifstat_inc(dstifp, ifs6_reass_ok);
1.2 itojun 519:
520: /*
521: * Tell launch routine the next header
522: */
523:
524: *mp = m;
525: *offp = offset;
526:
527: frag6_doing_reass = 0;
528: return nxt;
529:
530: dropfrag:
1.7 itojun 531: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 532: ip6stat.ip6s_fragdropped++;
533: m_freem(m);
534: return IPPROTO_DONE;
535: }
536:
537: /*
538: * Free a fragment reassembly header and all
539: * associated datagrams.
540: */
541: void
542: frag6_freef(q6)
543: struct ip6q *q6;
544: {
545: struct ip6asfrag *af6, *down6;
546:
547: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
548: af6 = down6) {
549: struct mbuf *m = IP6_REASS_MBUF(af6);
550:
551: down6 = af6->ip6af_down;
552: frag6_deq(af6);
553:
554: /*
555: * Return ICMP time exceeded error for the 1st fragment.
556: * Just free other fragments.
557: */
558: if (af6->ip6af_off == 0) {
559: struct ip6_hdr *ip6;
560:
561: /* adjust pointer */
562: ip6 = mtod(m, struct ip6_hdr *);
563:
564: /* restoure source and destination addresses */
565: ip6->ip6_src = q6->ip6q_src;
566: ip6->ip6_dst = q6->ip6q_dst;
567:
568: icmp6_error(m, ICMP6_TIME_EXCEEDED,
569: ICMP6_TIME_EXCEED_REASSEMBLY, 0);
1.9 itojun 570: } else
1.2 itojun 571: m_freem(m);
1.9 itojun 572: free(af6, M_FTABLE);
1.2 itojun 573: }
574: frag6_remque(q6);
575: free(q6, M_FTABLE);
576: frag6_nfragpackets--;
577: }
578:
579: /*
580: * Put an ip fragment on a reassembly chain.
581: * Like insque, but pointers in middle of structure.
582: */
583: void
584: frag6_enq(af6, up6)
585: struct ip6asfrag *af6, *up6;
586: {
587: af6->ip6af_up = up6;
588: af6->ip6af_down = up6->ip6af_down;
589: up6->ip6af_down->ip6af_up = af6;
590: up6->ip6af_down = af6;
591: }
592:
593: /*
594: * To frag6_enq as remque is to insque.
595: */
596: void
597: frag6_deq(af6)
598: struct ip6asfrag *af6;
599: {
600: af6->ip6af_up->ip6af_down = af6->ip6af_down;
601: af6->ip6af_down->ip6af_up = af6->ip6af_up;
602: }
603:
604: void
605: frag6_insque(new, old)
606: struct ip6q *new, *old;
607: {
608: new->ip6q_prev = old;
609: new->ip6q_next = old->ip6q_next;
610: old->ip6q_next->ip6q_prev= new;
611: old->ip6q_next = new;
612: }
613:
614: void
615: frag6_remque(p6)
616: struct ip6q *p6;
617: {
618: p6->ip6q_prev->ip6q_next = p6->ip6q_next;
619: p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
620: }
621:
622: /*
623: * IP timer processing;
624: * if a timer expires on a reassembly
625: * queue, discard it.
626: */
627: void
628: frag6_slowtimo()
629: {
630: struct ip6q *q6;
1.4 itojun 631: int s = splsoftnet();
1.2 itojun 632: #if 0
633: extern struct route_in6 ip6_forward_rt;
634: #endif
635:
636: frag6_doing_reass = 1;
637: q6 = ip6q.ip6q_next;
638: if (q6)
639: while (q6 != &ip6q) {
640: --q6->ip6q_ttl;
641: q6 = q6->ip6q_next;
642: if (q6->ip6q_prev->ip6q_ttl == 0) {
643: ip6stat.ip6s_fragtimeout++;
1.7 itojun 644: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 645: frag6_freef(q6->ip6q_prev);
646: }
647: }
648: /*
649: * If we are over the maximum number of fragments
650: * (due to the limit being lowered), drain off
651: * enough to get down to the new limit.
652: */
653: while (frag6_nfragpackets > (u_int)ip6_maxfragpackets) {
654: ip6stat.ip6s_fragoverflow++;
1.7 itojun 655: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 656: frag6_freef(ip6q.ip6q_prev);
657: }
658: frag6_doing_reass = 0;
659:
660: #if 0
661: /*
662: * Routing changes might produce a better route than we last used;
663: * make sure we notice eventually, even if forwarding only for one
664: * destination and the cache is never replaced.
665: */
666: if (ip6_forward_rt.ro_rt) {
667: RTFREE(ip6_forward_rt.ro_rt);
668: ip6_forward_rt.ro_rt = 0;
669: }
670: if (ipsrcchk_rt.ro_rt) {
671: RTFREE(ipsrcchk_rt.ro_rt);
672: ipsrcchk_rt.ro_rt = 0;
673: }
674: #endif
675:
676: splx(s);
677: }
678:
679: /*
680: * Drain off all datagram fragments.
681: */
682: void
683: frag6_drain()
684: {
685: if (frag6_doing_reass)
686: return;
687: while (ip6q.ip6q_next != &ip6q) {
688: ip6stat.ip6s_fragdropped++;
1.7 itojun 689: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 690: frag6_freef(ip6q.ip6q_next);
691: }
692: }
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