Annotation of src/sys/netinet6/frag6.c, Revision 1.10
1.10 ! itojun 1: /* $NetBSD: frag6.c,v 1.9 2000/02/03 18:13:01 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:
69: int frag6_doing_reass;
70: u_int frag6_nfragpackets;
71: struct ip6q ip6q; /* ip6 reassemble queue */
72:
1.9 itojun 73: #ifndef offsetof /* XXX */
74: #define offsetof(type, member) ((size_t)(&((type *)0)->member))
75: #endif
76:
1.2 itojun 77: /*
78: * Initialise reassembly queue and fragment identifier.
79: */
80: void
81: frag6_init()
82: {
1.6 itojun 83: struct timeval tv;
84:
85: /*
86: * in many cases, random() here does NOT return random number
87: * as initialization during bootstrap time occur in fixed order.
88: */
89: microtime(&tv);
1.9 itojun 90: ip6_id = random() ^ tv.tv_usec;
1.2 itojun 91: ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
92: }
93:
94: /*
1.9 itojun 95: * In RFC2460, fragment and reassembly rule do not agree with each other,
96: * in terms of next header field handling in fragment header.
97: * While the sender will use the same value for all of the fragmented packets,
98: * receiver is suggested not to check the consistency.
99: *
100: * fragment rule (p20):
101: * (2) A Fragment header containing:
102: * The Next Header value that identifies the first header of
103: * the Fragmentable Part of the original packet.
104: * -> next header field is same for all fragments
105: *
106: * reassembly rule (p21):
107: * The Next Header field of the last header of the Unfragmentable
108: * Part is obtained from the Next Header field of the first
109: * fragment's Fragment header.
110: * -> should grab it from the first fragment only
111: *
112: * The following note also contradicts with fragment rule - noone is going to
113: * send different fragment with different next header field.
114: *
115: * additional note (p22):
116: * The Next Header values in the Fragment headers of different
117: * fragments of the same original packet may differ. Only the value
118: * from the Offset zero fragment packet is used for reassembly.
119: * -> should grab it from the first fragment only
120: *
121: * There is no explicit reason given in the RFC. Historical reason maybe?
122: */
123: /*
1.2 itojun 124: * Fragment input
125: */
126: int
127: frag6_input(mp, offp, proto)
128: struct mbuf **mp;
129: int *offp, proto;
130: {
131: struct mbuf *m = *mp, *t;
132: struct ip6_hdr *ip6;
133: struct ip6_frag *ip6f;
134: struct ip6q *q6;
1.9 itojun 135: struct ip6asfrag *af6, *ip6af, *af6dwn;
1.2 itojun 136: int offset = *offp, nxt, i, next;
137: int first_frag = 0;
1.9 itojun 138: int fragoff, frgpartlen; /* must be larger than u_int16_t */
1.7 itojun 139: struct ifnet *dstifp;
140: #ifdef IN6_IFSTAT_STRICT
141: static struct route_in6 ro;
142: struct sockaddr_in6 *dst;
143: #endif
1.2 itojun 144:
1.7 itojun 145: ip6 = mtod(m, struct ip6_hdr *);
146: #ifndef PULLDOWN_TEST
1.2 itojun 147: IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
1.7 itojun 148: ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
149: #else
150: IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
151: if (ip6f == NULL)
152: return IPPROTO_DONE;
153: #endif
1.2 itojun 154:
1.7 itojun 155: dstifp = NULL;
156: #ifdef IN6_IFSTAT_STRICT
157: /* find the destination interface of the packet. */
158: dst = (struct sockaddr_in6 *)&ro.ro_dst;
159: if (ro.ro_rt
160: && ((ro.ro_rt->rt_flags & RTF_UP) == 0
161: || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) {
162: RTFREE(ro.ro_rt);
163: ro.ro_rt = (struct rtentry *)0;
164: }
165: if (ro.ro_rt == NULL) {
166: bzero(dst, sizeof(*dst));
167: dst->sin6_family = AF_INET6;
168: dst->sin6_len = sizeof(struct sockaddr_in6);
169: dst->sin6_addr = ip6->ip6_dst;
170: }
171: rtalloc((struct route *)&ro);
172: if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
173: dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
174: #else
175: /* we are violating the spec, this is not the destination interface */
176: if ((m->m_flags & M_PKTHDR) != 0)
177: dstifp = m->m_pkthdr.rcvif;
178: #endif
1.2 itojun 179:
180: /* jumbo payload can't contain a fragment header */
181: if (ip6->ip6_plen == 0) {
182: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
1.7 itojun 183: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 184: return IPPROTO_DONE;
185: }
186:
187: /*
188: * check whether fragment packet's fragment length is
189: * multiple of 8 octets.
190: * sizeof(struct ip6_frag) == 8
191: * sizeof(struct ip6_hdr) = 40
192: */
193: if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
194: (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
195: icmp6_error(m, ICMP6_PARAM_PROB,
196: ICMP6_PARAMPROB_HEADER,
1.9 itojun 197: offsetof(struct ip6_hdr, ip6_plen));
1.7 itojun 198: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 199: return IPPROTO_DONE;
200: }
201:
202: ip6stat.ip6s_fragments++;
1.7 itojun 203: in6_ifstat_inc(dstifp, ifs6_reass_reqd);
1.2 itojun 204:
1.9 itojun 205: /* offset now points to data portion */
1.2 itojun 206: offset += sizeof(struct ip6_frag);
207:
208: for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next)
209: if (ip6f->ip6f_ident == q6->ip6q_ident &&
210: IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
211: IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
212: break;
213:
214: if (q6 == &ip6q) {
215: /*
216: * the first fragment to arrive, create a reassembly queue.
217: */
218: first_frag = 1;
219: frag6_nfragpackets++;
220:
221: /*
222: * Enforce upper bound on number of fragmented packets
223: * for which we attempt reassembly;
224: * If maxfrag is 0, never accept fragments.
225: * If maxfrag is -1, accept all fragments without limitation.
226: */
227: if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) {
228: ip6stat.ip6s_fragoverflow++;
1.7 itojun 229: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 230: frag6_freef(ip6q.ip6q_prev);
231: }
232: q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
233: M_DONTWAIT);
234: if (q6 == NULL)
235: goto dropfrag;
1.9 itojun 236: bzero(q6, sizeof(*q6));
1.2 itojun 237:
238: frag6_insque(q6, &ip6q);
239:
1.9 itojun 240: /* ip6q_nxt will be filled afterwards, from 1st fragment */
1.2 itojun 241: q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
242: #ifdef notyet
243: q6->ip6q_nxtp = (u_char *)nxtp;
244: #endif
245: q6->ip6q_ident = ip6f->ip6f_ident;
246: q6->ip6q_arrive = 0; /* Is it used anywhere? */
247: q6->ip6q_ttl = IPV6_FRAGTTL;
248: q6->ip6q_src = ip6->ip6_src;
249: q6->ip6q_dst = ip6->ip6_dst;
250: q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
251: }
252:
253: /*
254: * If it's the 1st fragment, record the length of the
255: * unfragmentable part and the next header of the fragment header.
256: */
257: fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
258: if (fragoff == 0) {
259: q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr)
260: - sizeof(struct ip6_frag);
261: q6->ip6q_nxt = ip6f->ip6f_nxt;
262: }
263:
264: /*
265: * Check that the reassembled packet would not exceed 65535 bytes
266: * in size.
267: * If it would exceed, discard the fragment and return an ICMP error.
268: */
1.9 itojun 269: frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
1.2 itojun 270: if (q6->ip6q_unfrglen >= 0) {
271: /* The 1st fragment has already arrived. */
272: if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
273: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
1.9 itojun 274: offset - sizeof(struct ip6_frag) +
275: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 276: return(IPPROTO_DONE);
277: }
278: }
279: else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
280: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
1.9 itojun 281: offset - sizeof(struct ip6_frag) +
282: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 283: return(IPPROTO_DONE);
284: }
285: /*
286: * If it's the first fragment, do the above check for each
287: * fragment already stored in the reassembly queue.
288: */
289: if (fragoff == 0) {
290: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
291: af6 = af6dwn) {
292: af6dwn = af6->ip6af_down;
293:
294: if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen >
295: IPV6_MAXPACKET) {
296: struct mbuf *merr = IP6_REASS_MBUF(af6);
297: struct ip6_hdr *ip6err;
298: int erroff = af6->ip6af_offset;
299:
300: /* dequeue the fragment. */
301: frag6_deq(af6);
1.9 itojun 302: free(af6, M_FTABLE);
1.2 itojun 303:
304: /* adjust pointer. */
305: ip6err = mtod(merr, struct ip6_hdr *);
306:
307: /*
308: * Restore source and destination addresses
309: * in the erroneous IPv6 header.
310: */
311: ip6err->ip6_src = q6->ip6q_src;
312: ip6err->ip6_dst = q6->ip6q_dst;
313:
314: icmp6_error(merr, ICMP6_PARAM_PROB,
315: ICMP6_PARAMPROB_HEADER,
1.9 itojun 316: erroff - sizeof(struct ip6_frag) +
317: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 318: }
319: }
320: }
321:
1.9 itojun 322: ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
323: M_DONTWAIT);
324: if (ip6af == NULL)
325: goto dropfrag;
326: bzero(ip6af, sizeof(*ip6af));
327: ip6af->ip6af_head = ip6->ip6_flow;
328: ip6af->ip6af_len = ip6->ip6_plen;
329: ip6af->ip6af_nxt = ip6->ip6_nxt;
330: ip6af->ip6af_hlim = ip6->ip6_hlim;
1.2 itojun 331: ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
332: ip6af->ip6af_off = fragoff;
333: ip6af->ip6af_frglen = frgpartlen;
334: ip6af->ip6af_offset = offset;
335: IP6_REASS_MBUF(ip6af) = m;
336:
337: if (first_frag) {
338: af6 = (struct ip6asfrag *)q6;
339: goto insert;
340: }
341:
342: /*
343: * Find a segment which begins after this one does.
344: */
345: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
346: af6 = af6->ip6af_down)
347: if (af6->ip6af_off > ip6af->ip6af_off)
348: break;
349:
350: #if 0
351: /*
352: * If there is a preceding segment, it may provide some of
353: * our data already. If so, drop the data from the incoming
354: * segment. If it provides all of our data, drop us.
355: */
356: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
357: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
358: - ip6af->ip6af_off;
359: if (i > 0) {
360: if (i >= ip6af->ip6af_frglen)
361: goto dropfrag;
362: m_adj(IP6_REASS_MBUF(ip6af), i);
363: ip6af->ip6af_off += i;
364: ip6af->ip6af_frglen -= i;
365: }
366: }
367:
368: /*
369: * While we overlap succeeding segments trim them or,
370: * if they are completely covered, dequeue them.
371: */
372: while (af6 != (struct ip6asfrag *)q6 &&
373: ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
374: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
375: if (i < af6->ip6af_frglen) {
376: af6->ip6af_frglen -= i;
377: af6->ip6af_off += i;
378: m_adj(IP6_REASS_MBUF(af6), i);
379: break;
380: }
381: af6 = af6->ip6af_down;
382: m_freem(IP6_REASS_MBUF(af6->ip6af_up));
383: frag6_deq(af6->ip6af_up);
384: }
385: #else
386: /*
387: * If the incoming framgent overlaps some existing fragments in
388: * the reassembly queue, drop it, since it is dangerous to override
389: * existing fragments from a security point of view.
390: */
391: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
392: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
393: - ip6af->ip6af_off;
394: if (i > 0) {
395: log(LOG_ERR, "%d bytes of a fragment from %s "
396: "overlaps the previous fragment\n",
397: i, ip6_sprintf(&q6->ip6q_src));
398: goto dropfrag;
399: }
400: }
401: if (af6 != (struct ip6asfrag *)q6) {
402: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
403: if (i > 0) {
404: log(LOG_ERR, "%d bytes of a fragment from %s "
405: "overlaps the succeeding fragment",
406: i, ip6_sprintf(&q6->ip6q_src));
407: goto dropfrag;
408: }
409: }
410: #endif
411:
412: insert:
413:
414: /*
415: * Stick new segment in its place;
416: * check for complete reassembly.
417: * Move to front of packet queue, as we are
418: * the most recently active fragmented packet.
419: */
420: frag6_enq(ip6af, af6->ip6af_up);
421: #if 0 /* xxx */
422: if (q6 != ip6q.ip6q_next) {
423: frag6_remque(q6);
424: frag6_insque(q6, &ip6q);
425: }
426: #endif
427: next = 0;
428: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
429: af6 = af6->ip6af_down) {
430: if (af6->ip6af_off != next) {
431: frag6_doing_reass = 0;
432: return IPPROTO_DONE;
433: }
434: next += af6->ip6af_frglen;
435: }
436: if (af6->ip6af_up->ip6af_mff) {
437: frag6_doing_reass = 0;
438: return IPPROTO_DONE;
439: }
440:
441: /*
442: * Reassembly is complete; concatenate fragments.
443: */
444: ip6af = q6->ip6q_down;
445: t = m = IP6_REASS_MBUF(ip6af);
446: af6 = ip6af->ip6af_down;
1.9 itojun 447: frag6_deq(ip6af);
1.2 itojun 448: while (af6 != (struct ip6asfrag *)q6) {
1.9 itojun 449: af6dwn = af6->ip6af_down;
450: frag6_deq(af6);
1.2 itojun 451: while (t->m_next)
452: t = t->m_next;
453: t->m_next = IP6_REASS_MBUF(af6);
1.9 itojun 454: m_adj(t->m_next, af6->ip6af_offset);
455: free(af6, M_FTABLE);
456: af6 = af6dwn;
1.2 itojun 457: }
458:
459: /* adjust offset to point where the original next header starts */
460: offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
1.9 itojun 461: free(ip6af, M_FTABLE);
462: ip6 = mtod(m, struct ip6_hdr *);
1.2 itojun 463: ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr));
464: ip6->ip6_src = q6->ip6q_src;
465: ip6->ip6_dst = q6->ip6q_dst;
466: nxt = q6->ip6q_nxt;
467: #ifdef notyet
468: *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
469: #endif
470:
471: /*
472: * Delete frag6 header with as a few cost as possible.
473: */
1.9 itojun 474: if (offset < m->m_len) {
1.7 itojun 475: ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
1.2 itojun 476: offset);
1.9 itojun 477: m->m_data += sizeof(struct ip6_frag);
478: m->m_len -= sizeof(struct ip6_frag);
479: } else {
480: /* this comes with no copy if the boundary is on cluster */
481: if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
482: frag6_remque(q6);
483: free(q6, M_FTABLE);
484: frag6_nfragpackets--;
485: goto dropfrag;
486: }
487: m_adj(t, sizeof(struct ip6_frag));
488: m_cat(m, t);
1.2 itojun 489: }
490:
491: /*
492: * Store NXT to the original.
493: */
494: {
495: char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
496: *prvnxtp = nxt;
497: }
498:
499: frag6_remque(q6);
500: free(q6, M_FTABLE);
501: frag6_nfragpackets--;
502:
503: if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
504: int plen = 0;
505: for (t = m; t; t = t->m_next)
506: plen += t->m_len;
507: m->m_pkthdr.len = plen;
508: }
509:
510: ip6stat.ip6s_reassembled++;
1.7 itojun 511: in6_ifstat_inc(dstifp, ifs6_reass_ok);
1.2 itojun 512:
513: /*
514: * Tell launch routine the next header
515: */
516:
517: *mp = m;
518: *offp = offset;
519:
520: frag6_doing_reass = 0;
521: return nxt;
522:
523: dropfrag:
1.7 itojun 524: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 525: ip6stat.ip6s_fragdropped++;
526: m_freem(m);
527: return IPPROTO_DONE;
528: }
529:
530: /*
531: * Free a fragment reassembly header and all
532: * associated datagrams.
533: */
534: void
535: frag6_freef(q6)
536: struct ip6q *q6;
537: {
538: struct ip6asfrag *af6, *down6;
539:
540: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
541: af6 = down6) {
542: struct mbuf *m = IP6_REASS_MBUF(af6);
543:
544: down6 = af6->ip6af_down;
545: frag6_deq(af6);
546:
547: /*
548: * Return ICMP time exceeded error for the 1st fragment.
549: * Just free other fragments.
550: */
551: if (af6->ip6af_off == 0) {
552: struct ip6_hdr *ip6;
553:
554: /* adjust pointer */
555: ip6 = mtod(m, struct ip6_hdr *);
556:
557: /* restoure source and destination addresses */
558: ip6->ip6_src = q6->ip6q_src;
559: ip6->ip6_dst = q6->ip6q_dst;
560:
561: icmp6_error(m, ICMP6_TIME_EXCEEDED,
562: ICMP6_TIME_EXCEED_REASSEMBLY, 0);
1.9 itojun 563: } else
1.2 itojun 564: m_freem(m);
1.9 itojun 565: free(af6, M_FTABLE);
1.2 itojun 566: }
567: frag6_remque(q6);
568: free(q6, M_FTABLE);
569: frag6_nfragpackets--;
570: }
571:
572: /*
573: * Put an ip fragment on a reassembly chain.
574: * Like insque, but pointers in middle of structure.
575: */
576: void
577: frag6_enq(af6, up6)
578: struct ip6asfrag *af6, *up6;
579: {
580: af6->ip6af_up = up6;
581: af6->ip6af_down = up6->ip6af_down;
582: up6->ip6af_down->ip6af_up = af6;
583: up6->ip6af_down = af6;
584: }
585:
586: /*
587: * To frag6_enq as remque is to insque.
588: */
589: void
590: frag6_deq(af6)
591: struct ip6asfrag *af6;
592: {
593: af6->ip6af_up->ip6af_down = af6->ip6af_down;
594: af6->ip6af_down->ip6af_up = af6->ip6af_up;
595: }
596:
597: void
598: frag6_insque(new, old)
599: struct ip6q *new, *old;
600: {
601: new->ip6q_prev = old;
602: new->ip6q_next = old->ip6q_next;
603: old->ip6q_next->ip6q_prev= new;
604: old->ip6q_next = new;
605: }
606:
607: void
608: frag6_remque(p6)
609: struct ip6q *p6;
610: {
611: p6->ip6q_prev->ip6q_next = p6->ip6q_next;
612: p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
613: }
614:
615: /*
616: * IP timer processing;
617: * if a timer expires on a reassembly
618: * queue, discard it.
619: */
620: void
621: frag6_slowtimo()
622: {
623: struct ip6q *q6;
1.4 itojun 624: int s = splsoftnet();
1.2 itojun 625: #if 0
626: extern struct route_in6 ip6_forward_rt;
627: #endif
628:
629: frag6_doing_reass = 1;
630: q6 = ip6q.ip6q_next;
631: if (q6)
632: while (q6 != &ip6q) {
633: --q6->ip6q_ttl;
634: q6 = q6->ip6q_next;
635: if (q6->ip6q_prev->ip6q_ttl == 0) {
636: ip6stat.ip6s_fragtimeout++;
1.7 itojun 637: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 638: frag6_freef(q6->ip6q_prev);
639: }
640: }
641: /*
642: * If we are over the maximum number of fragments
643: * (due to the limit being lowered), drain off
644: * enough to get down to the new limit.
645: */
646: while (frag6_nfragpackets > (u_int)ip6_maxfragpackets) {
647: ip6stat.ip6s_fragoverflow++;
1.7 itojun 648: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 649: frag6_freef(ip6q.ip6q_prev);
650: }
651: frag6_doing_reass = 0;
652:
653: #if 0
654: /*
655: * Routing changes might produce a better route than we last used;
656: * make sure we notice eventually, even if forwarding only for one
657: * destination and the cache is never replaced.
658: */
659: if (ip6_forward_rt.ro_rt) {
660: RTFREE(ip6_forward_rt.ro_rt);
661: ip6_forward_rt.ro_rt = 0;
662: }
663: if (ipsrcchk_rt.ro_rt) {
664: RTFREE(ipsrcchk_rt.ro_rt);
665: ipsrcchk_rt.ro_rt = 0;
666: }
667: #endif
668:
669: splx(s);
670: }
671:
672: /*
673: * Drain off all datagram fragments.
674: */
675: void
676: frag6_drain()
677: {
678: if (frag6_doing_reass)
679: return;
680: while (ip6q.ip6q_next != &ip6q) {
681: ip6stat.ip6s_fragdropped++;
1.7 itojun 682: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 683: frag6_freef(ip6q.ip6q_next);
684: }
685: }
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