Annotation of src/sys/netinet6/frag6.c, Revision 1.35
1.35 ! dyoung 1: /* $NetBSD: frag6.c,v 1.34 2007/01/26 19:02:02 dyoung Exp $ */
1.18 itojun 2: /* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun Exp $ */
1.3 thorpej 3:
1.2 itojun 4: /*
5: * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6: * All rights reserved.
1.11 itojun 7: *
1.2 itojun 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.
1.11 itojun 19: *
1.2 itojun 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: */
1.16 lukem 32:
33: #include <sys/cdefs.h>
1.35 ! dyoung 34: __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.34 2007/01/26 19:02:02 dyoung Exp $");
1.2 itojun 35:
36: #include <sys/param.h>
37: #include <sys/systm.h>
38: #include <sys/malloc.h>
39: #include <sys/mbuf.h>
40: #include <sys/domain.h>
41: #include <sys/protosw.h>
42: #include <sys/socket.h>
43: #include <sys/errno.h>
44: #include <sys/time.h>
45: #include <sys/kernel.h>
46: #include <sys/syslog.h>
47:
48: #include <net/if.h>
49: #include <net/route.h>
50:
51: #include <netinet/in.h>
52: #include <netinet/in_var.h>
1.10 itojun 53: #include <netinet/ip6.h>
1.2 itojun 54: #include <netinet6/ip6_var.h>
1.10 itojun 55: #include <netinet/icmp6.h>
1.2 itojun 56:
1.7 itojun 57: #include <net/net_osdep.h>
58:
59: /*
60: * Define it to get a correct behavior on per-interface statistics.
61: * You will need to perform an extra routing table lookup, per fragment,
62: * to do it. This may, or may not be, a performance hit.
63: */
64: #define IN6_IFSTAT_STRICT
65:
1.2 itojun 66: static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
67: static void frag6_deq __P((struct ip6asfrag *));
68: static void frag6_insque __P((struct ip6q *, struct ip6q *));
69: static void frag6_remque __P((struct ip6q *));
70: static void frag6_freef __P((struct ip6q *));
71:
1.17 itojun 72: static int ip6q_locked;
1.2 itojun 73: u_int frag6_nfragpackets;
1.18 itojun 74: u_int frag6_nfrags;
1.2 itojun 75: struct ip6q ip6q; /* ip6 reassemble queue */
76:
1.28 perry 77: static inline int ip6q_lock_try __P((void));
78: static inline void ip6q_unlock __P((void));
1.17 itojun 79:
1.28 perry 80: static inline int
1.17 itojun 81: ip6q_lock_try()
82: {
83: int s;
84:
85: /*
86: * Use splvm() -- we're bloking things that would cause
87: * mbuf allocation.
88: */
89: s = splvm();
90: if (ip6q_locked) {
91: splx(s);
92: return (0);
93: }
94: ip6q_locked = 1;
95: splx(s);
96: return (1);
97: }
98:
1.28 perry 99: static inline void
1.17 itojun 100: ip6q_unlock()
101: {
102: int s;
103:
104: s = splvm();
105: ip6q_locked = 0;
106: splx(s);
107: }
108:
109: #ifdef DIAGNOSTIC
110: #define IP6Q_LOCK() \
111: do { \
112: if (ip6q_lock_try() == 0) { \
113: printf("%s:%d: ip6q already locked\n", __FILE__, __LINE__); \
114: panic("ip6q_lock"); \
115: } \
1.23 perry 116: } while (/*CONSTCOND*/ 0)
1.17 itojun 117: #define IP6Q_LOCK_CHECK() \
118: do { \
119: if (ip6q_locked == 0) { \
120: printf("%s:%d: ip6q lock not held\n", __FILE__, __LINE__); \
121: panic("ip6q lock check"); \
122: } \
1.23 perry 123: } while (/*CONSTCOND*/ 0)
1.17 itojun 124: #else
125: #define IP6Q_LOCK() (void) ip6q_lock_try()
126: #define IP6Q_LOCK_CHECK() /* nothing */
127: #endif
128:
129: #define IP6Q_UNLOCK() ip6q_unlock()
130:
1.9 itojun 131: #ifndef offsetof /* XXX */
132: #define offsetof(type, member) ((size_t)(&((type *)0)->member))
1.12 itojun 133: #endif
1.9 itojun 134:
1.2 itojun 135: /*
136: * Initialise reassembly queue and fragment identifier.
137: */
138: void
139: frag6_init()
140: {
1.6 itojun 141:
1.2 itojun 142: ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q;
143: }
144:
145: /*
1.9 itojun 146: * In RFC2460, fragment and reassembly rule do not agree with each other,
147: * in terms of next header field handling in fragment header.
148: * While the sender will use the same value for all of the fragmented packets,
149: * receiver is suggested not to check the consistency.
150: *
151: * fragment rule (p20):
152: * (2) A Fragment header containing:
153: * The Next Header value that identifies the first header of
154: * the Fragmentable Part of the original packet.
155: * -> next header field is same for all fragments
156: *
1.11 itojun 157: * reassembly rule (p21):
1.9 itojun 158: * The Next Header field of the last header of the Unfragmentable
159: * Part is obtained from the Next Header field of the first
160: * fragment's Fragment header.
161: * -> should grab it from the first fragment only
162: *
163: * The following note also contradicts with fragment rule - noone is going to
164: * send different fragment with different next header field.
165: *
166: * additional note (p22):
167: * The Next Header values in the Fragment headers of different
168: * fragments of the same original packet may differ. Only the value
169: * from the Offset zero fragment packet is used for reassembly.
170: * -> should grab it from the first fragment only
171: *
172: * There is no explicit reason given in the RFC. Historical reason maybe?
173: */
174: /*
1.2 itojun 175: * Fragment input
176: */
177: int
1.31 christos 178: frag6_input(struct mbuf **mp, int *offp, int proto)
1.2 itojun 179: {
180: struct mbuf *m = *mp, *t;
181: struct ip6_hdr *ip6;
182: struct ip6_frag *ip6f;
183: struct ip6q *q6;
1.9 itojun 184: struct ip6asfrag *af6, *ip6af, *af6dwn;
1.2 itojun 185: int offset = *offp, nxt, i, next;
186: int first_frag = 0;
1.9 itojun 187: int fragoff, frgpartlen; /* must be larger than u_int16_t */
1.7 itojun 188: struct ifnet *dstifp;
189: #ifdef IN6_IFSTAT_STRICT
190: static struct route_in6 ro;
1.35 ! dyoung 191: const struct sockaddr_in6 *cdst;
1.7 itojun 192: #endif
1.2 itojun 193:
1.7 itojun 194: ip6 = mtod(m, struct ip6_hdr *);
195: IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
196: if (ip6f == NULL)
197: return IPPROTO_DONE;
1.2 itojun 198:
1.7 itojun 199: dstifp = NULL;
200: #ifdef IN6_IFSTAT_STRICT
201: /* find the destination interface of the packet. */
1.35 ! dyoung 202: cdst = (const struct sockaddr_in6 *)rtcache_getdst((struct route *)&ro);
! 203: if (!IN6_ARE_ADDR_EQUAL(&cdst->sin6_addr, &ip6->ip6_dst))
1.33 joerg 204: rtcache_free((struct route *)&ro);
205: else
206: rtcache_check((struct route *)&ro);
1.7 itojun 207: if (ro.ro_rt == NULL) {
1.35 ! dyoung 208: struct sockaddr_in6 *dst;
! 209:
! 210: dst = (struct sockaddr_in6 *)&ro.ro_dst;
1.34 dyoung 211: memset(dst, 0, sizeof(*dst));
1.7 itojun 212: dst->sin6_family = AF_INET6;
213: dst->sin6_len = sizeof(struct sockaddr_in6);
214: dst->sin6_addr = ip6->ip6_dst;
1.33 joerg 215: rtcache_init((struct route *)&ro);
1.7 itojun 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
1.2 itojun 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);
1.7 itojun 228: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 229: return IPPROTO_DONE;
230: }
231:
232: /*
233: * check whether fragment packet's fragment length is
1.11 itojun 234: * multiple of 8 octets.
1.2 itojun 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)) {
1.18 itojun 240: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
241: offsetof(struct ip6_hdr, ip6_plen));
1.7 itojun 242: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 243: return IPPROTO_DONE;
244: }
245:
246: ip6stat.ip6s_fragments++;
1.7 itojun 247: in6_ifstat_inc(dstifp, ifs6_reass_reqd);
1.20 itojun 248:
1.9 itojun 249: /* offset now points to data portion */
1.2 itojun 250: offset += sizeof(struct ip6_frag);
251:
1.17 itojun 252: IP6Q_LOCK();
1.12 itojun 253:
1.18 itojun 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:
1.2 itojun 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
1.11 itojun 278: * for which we attempt reassembly;
1.18 itojun 279: * If maxfragpackets is 0, never accept fragments.
280: * If maxfragpackets is -1, accept all fragments without
281: * limitation.
1.2 itojun 282: */
1.13 itojun 283: if (ip6_maxfragpackets < 0)
284: ;
285: else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
286: goto dropfrag;
287: frag6_nfragpackets++;
1.2 itojun 288: q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
1.18 itojun 289: M_DONTWAIT);
1.2 itojun 290: if (q6 == NULL)
291: goto dropfrag;
1.9 itojun 292: bzero(q6, sizeof(*q6));
1.2 itojun 293:
294: frag6_insque(q6, &ip6q);
295:
1.9 itojun 296: /* ip6q_nxt will be filled afterwards, from 1st fragment */
1.2 itojun 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. */
1.18 itojun 307:
308: q6->ip6q_nfrag = 0;
1.2 itojun 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) {
1.18 itojun 317: q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
318: sizeof(struct ip6_frag);
1.2 itojun 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: */
1.9 itojun 327: frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
1.2 itojun 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,
1.18 itojun 332: offset - sizeof(struct ip6_frag) +
333: offsetof(struct ip6_frag, ip6f_offlg));
1.17 itojun 334: IP6Q_UNLOCK();
1.22 itojun 335: return (IPPROTO_DONE);
1.2 itojun 336: }
1.18 itojun 337: } else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
1.2 itojun 338: icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
1.9 itojun 339: offset - sizeof(struct ip6_frag) +
340: offsetof(struct ip6_frag, ip6f_offlg));
1.17 itojun 341: IP6Q_UNLOCK();
1.22 itojun 342: return (IPPROTO_DONE);
1.2 itojun 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);
1.9 itojun 361: free(af6, M_FTABLE);
1.2 itojun 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,
1.18 itojun 374: ICMP6_PARAMPROB_HEADER,
375: erroff - sizeof(struct ip6_frag) +
376: offsetof(struct ip6_frag, ip6f_offlg));
1.2 itojun 377: }
378: }
379: }
380:
1.9 itojun 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;
1.2 itojun 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: * Find a segment which begins after this one does.
403: */
404: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
405: af6 = af6->ip6af_down)
406: if (af6->ip6af_off > ip6af->ip6af_off)
407: break;
408:
409: #if 0
410: /*
411: * If there is a preceding segment, it may provide some of
412: * our data already. If so, drop the data from the incoming
413: * segment. If it provides all of our data, drop us.
414: */
415: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
416: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
417: - ip6af->ip6af_off;
418: if (i > 0) {
419: if (i >= ip6af->ip6af_frglen)
420: goto dropfrag;
421: m_adj(IP6_REASS_MBUF(ip6af), i);
422: ip6af->ip6af_off += i;
423: ip6af->ip6af_frglen -= i;
424: }
425: }
426:
427: /*
428: * While we overlap succeeding segments trim them or,
429: * if they are completely covered, dequeue them.
430: */
431: while (af6 != (struct ip6asfrag *)q6 &&
432: ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
433: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
434: if (i < af6->ip6af_frglen) {
435: af6->ip6af_frglen -= i;
436: af6->ip6af_off += i;
437: m_adj(IP6_REASS_MBUF(af6), i);
438: break;
439: }
440: af6 = af6->ip6af_down;
441: m_freem(IP6_REASS_MBUF(af6->ip6af_up));
442: frag6_deq(af6->ip6af_up);
443: }
444: #else
445: /*
446: * If the incoming framgent overlaps some existing fragments in
447: * the reassembly queue, drop it, since it is dangerous to override
448: * existing fragments from a security point of view.
1.18 itojun 449: * We don't know which fragment is the bad guy - here we trust
450: * fragment that came in earlier, with no real reason.
1.2 itojun 451: */
452: if (af6->ip6af_up != (struct ip6asfrag *)q6) {
453: i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
454: - ip6af->ip6af_off;
455: if (i > 0) {
1.14 itojun 456: #if 0 /* suppress the noisy log */
1.2 itojun 457: log(LOG_ERR, "%d bytes of a fragment from %s "
458: "overlaps the previous fragment\n",
459: i, ip6_sprintf(&q6->ip6q_src));
1.14 itojun 460: #endif
461: free(ip6af, M_FTABLE);
1.2 itojun 462: goto dropfrag;
463: }
464: }
465: if (af6 != (struct ip6asfrag *)q6) {
466: i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
467: if (i > 0) {
1.14 itojun 468: #if 0 /* suppress the noisy log */
1.2 itojun 469: log(LOG_ERR, "%d bytes of a fragment from %s "
470: "overlaps the succeeding fragment",
471: i, ip6_sprintf(&q6->ip6q_src));
1.14 itojun 472: #endif
473: free(ip6af, M_FTABLE);
1.2 itojun 474: goto dropfrag;
475: }
476: }
477: #endif
478:
479: insert:
480:
481: /*
482: * Stick new segment in its place;
483: * check for complete reassembly.
484: * Move to front of packet queue, as we are
485: * the most recently active fragmented packet.
486: */
487: frag6_enq(ip6af, af6->ip6af_up);
1.18 itojun 488: frag6_nfrags++;
489: q6->ip6q_nfrag++;
1.2 itojun 490: #if 0 /* xxx */
491: if (q6 != ip6q.ip6q_next) {
492: frag6_remque(q6);
493: frag6_insque(q6, &ip6q);
494: }
495: #endif
496: next = 0;
497: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
498: af6 = af6->ip6af_down) {
499: if (af6->ip6af_off != next) {
1.17 itojun 500: IP6Q_UNLOCK();
1.2 itojun 501: return IPPROTO_DONE;
502: }
503: next += af6->ip6af_frglen;
504: }
505: if (af6->ip6af_up->ip6af_mff) {
1.17 itojun 506: IP6Q_UNLOCK();
1.2 itojun 507: return IPPROTO_DONE;
508: }
509:
510: /*
511: * Reassembly is complete; concatenate fragments.
512: */
513: ip6af = q6->ip6q_down;
514: t = m = IP6_REASS_MBUF(ip6af);
515: af6 = ip6af->ip6af_down;
1.9 itojun 516: frag6_deq(ip6af);
1.2 itojun 517: while (af6 != (struct ip6asfrag *)q6) {
1.9 itojun 518: af6dwn = af6->ip6af_down;
519: frag6_deq(af6);
1.2 itojun 520: while (t->m_next)
521: t = t->m_next;
522: t->m_next = IP6_REASS_MBUF(af6);
1.9 itojun 523: m_adj(t->m_next, af6->ip6af_offset);
524: free(af6, M_FTABLE);
525: af6 = af6dwn;
1.2 itojun 526: }
527:
528: /* adjust offset to point where the original next header starts */
529: offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
1.9 itojun 530: free(ip6af, M_FTABLE);
531: ip6 = mtod(m, struct ip6_hdr *);
1.25 itojun 532: ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr));
1.2 itojun 533: ip6->ip6_src = q6->ip6q_src;
534: ip6->ip6_dst = q6->ip6q_dst;
535: nxt = q6->ip6q_nxt;
536: #ifdef notyet
537: *q6->ip6q_nxtp = (u_char)(nxt & 0xff);
538: #endif
539:
540: /*
541: * Delete frag6 header with as a few cost as possible.
542: */
1.9 itojun 543: if (offset < m->m_len) {
1.7 itojun 544: ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag),
1.2 itojun 545: offset);
1.9 itojun 546: m->m_data += sizeof(struct ip6_frag);
547: m->m_len -= sizeof(struct ip6_frag);
548: } else {
549: /* this comes with no copy if the boundary is on cluster */
550: if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) {
551: frag6_remque(q6);
1.18 itojun 552: frag6_nfrags -= q6->ip6q_nfrag;
1.9 itojun 553: free(q6, M_FTABLE);
554: frag6_nfragpackets--;
555: goto dropfrag;
556: }
557: m_adj(t, sizeof(struct ip6_frag));
558: m_cat(m, t);
1.2 itojun 559: }
560:
561: /*
562: * Store NXT to the original.
563: */
564: {
1.21 itojun 565: u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
1.2 itojun 566: *prvnxtp = nxt;
567: }
568:
569: frag6_remque(q6);
1.18 itojun 570: frag6_nfrags -= q6->ip6q_nfrag;
1.2 itojun 571: free(q6, M_FTABLE);
572: frag6_nfragpackets--;
573:
574: if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
575: int plen = 0;
576: for (t = m; t; t = t->m_next)
577: plen += t->m_len;
578: m->m_pkthdr.len = plen;
579: }
1.20 itojun 580:
1.2 itojun 581: ip6stat.ip6s_reassembled++;
1.7 itojun 582: in6_ifstat_inc(dstifp, ifs6_reass_ok);
1.2 itojun 583:
584: /*
585: * Tell launch routine the next header
586: */
587:
588: *mp = m;
589: *offp = offset;
590:
1.17 itojun 591: IP6Q_UNLOCK();
1.2 itojun 592: return nxt;
593:
594: dropfrag:
1.7 itojun 595: in6_ifstat_inc(dstifp, ifs6_reass_fail);
1.2 itojun 596: ip6stat.ip6s_fragdropped++;
597: m_freem(m);
1.17 itojun 598: IP6Q_UNLOCK();
1.2 itojun 599: return IPPROTO_DONE;
600: }
601:
602: /*
603: * Free a fragment reassembly header and all
604: * associated datagrams.
605: */
606: void
607: frag6_freef(q6)
608: struct ip6q *q6;
609: {
610: struct ip6asfrag *af6, *down6;
611:
1.17 itojun 612: IP6Q_LOCK_CHECK();
613:
1.2 itojun 614: for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
615: af6 = down6) {
616: struct mbuf *m = IP6_REASS_MBUF(af6);
617:
618: down6 = af6->ip6af_down;
619: frag6_deq(af6);
620:
621: /*
622: * Return ICMP time exceeded error for the 1st fragment.
623: * Just free other fragments.
624: */
625: if (af6->ip6af_off == 0) {
626: struct ip6_hdr *ip6;
627:
628: /* adjust pointer */
629: ip6 = mtod(m, struct ip6_hdr *);
630:
631: /* restoure source and destination addresses */
632: ip6->ip6_src = q6->ip6q_src;
633: ip6->ip6_dst = q6->ip6q_dst;
634:
635: icmp6_error(m, ICMP6_TIME_EXCEEDED,
636: ICMP6_TIME_EXCEED_REASSEMBLY, 0);
1.9 itojun 637: } else
1.2 itojun 638: m_freem(m);
1.9 itojun 639: free(af6, M_FTABLE);
1.2 itojun 640: }
641: frag6_remque(q6);
1.18 itojun 642: frag6_nfrags -= q6->ip6q_nfrag;
1.2 itojun 643: free(q6, M_FTABLE);
644: frag6_nfragpackets--;
645: }
646:
647: /*
648: * Put an ip fragment on a reassembly chain.
649: * Like insque, but pointers in middle of structure.
650: */
651: void
652: frag6_enq(af6, up6)
653: struct ip6asfrag *af6, *up6;
654: {
1.17 itojun 655:
656: IP6Q_LOCK_CHECK();
657:
1.2 itojun 658: af6->ip6af_up = up6;
659: af6->ip6af_down = up6->ip6af_down;
660: up6->ip6af_down->ip6af_up = af6;
661: up6->ip6af_down = af6;
662: }
663:
664: /*
665: * To frag6_enq as remque is to insque.
666: */
667: void
668: frag6_deq(af6)
669: struct ip6asfrag *af6;
670: {
1.17 itojun 671:
672: IP6Q_LOCK_CHECK();
673:
1.2 itojun 674: af6->ip6af_up->ip6af_down = af6->ip6af_down;
675: af6->ip6af_down->ip6af_up = af6->ip6af_up;
676: }
677:
1.11 itojun 678: void
1.2 itojun 679: frag6_insque(new, old)
680: struct ip6q *new, *old;
681: {
1.17 itojun 682:
683: IP6Q_LOCK_CHECK();
684:
1.2 itojun 685: new->ip6q_prev = old;
686: new->ip6q_next = old->ip6q_next;
687: old->ip6q_next->ip6q_prev= new;
688: old->ip6q_next = new;
689: }
690:
691: void
692: frag6_remque(p6)
693: struct ip6q *p6;
694: {
1.17 itojun 695:
696: IP6Q_LOCK_CHECK();
697:
1.2 itojun 698: p6->ip6q_prev->ip6q_next = p6->ip6q_next;
699: p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
700: }
701:
702: /*
1.11 itojun 703: * IPv6 reassembling timer processing;
1.2 itojun 704: * if a timer expires on a reassembly
705: * queue, discard it.
706: */
707: void
708: frag6_slowtimo()
709: {
710: struct ip6q *q6;
1.4 itojun 711: int s = splsoftnet();
1.2 itojun 712:
1.17 itojun 713: IP6Q_LOCK();
1.2 itojun 714: q6 = ip6q.ip6q_next;
715: if (q6)
716: while (q6 != &ip6q) {
717: --q6->ip6q_ttl;
718: q6 = q6->ip6q_next;
719: if (q6->ip6q_prev->ip6q_ttl == 0) {
720: ip6stat.ip6s_fragtimeout++;
1.7 itojun 721: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 722: frag6_freef(q6->ip6q_prev);
723: }
724: }
725: /*
726: * If we are over the maximum number of fragments
727: * (due to the limit being lowered), drain off
728: * enough to get down to the new limit.
729: */
1.13 itojun 730: while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
731: ip6q.ip6q_prev) {
1.2 itojun 732: ip6stat.ip6s_fragoverflow++;
1.7 itojun 733: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 734: frag6_freef(ip6q.ip6q_prev);
735: }
1.17 itojun 736: IP6Q_UNLOCK();
1.2 itojun 737:
738: #if 0
739: /*
740: * Routing changes might produce a better route than we last used;
741: * make sure we notice eventually, even if forwarding only for one
742: * destination and the cache is never replaced.
743: */
1.33 joerg 744: rtcache_free((struct route *)&ip6_forward_rt);
745: rtcache_free((struct route *)&ipsrcchk_rt);
1.2 itojun 746: #endif
747:
748: splx(s);
749: }
750:
751: /*
752: * Drain off all datagram fragments.
753: */
754: void
755: frag6_drain()
756: {
1.17 itojun 757:
758: if (ip6q_lock_try() == 0)
1.2 itojun 759: return;
760: while (ip6q.ip6q_next != &ip6q) {
761: ip6stat.ip6s_fragdropped++;
1.7 itojun 762: /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
1.2 itojun 763: frag6_freef(ip6q.ip6q_next);
764: }
1.17 itojun 765: IP6Q_UNLOCK();
1.2 itojun 766: }
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