blob: e4fe9ee484ddab3d0f0fee7e0153e8de4f14c4be [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IPv6 fragment reassembly
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $
9 *
10 * Based on: net/ipv4/ip_fragment.c
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18/*
19 * Fixes:
20 * Andi Kleen Make it work with multiple hosts.
21 * More RFC compliance.
22 *
23 * Horst von Brand Add missing #include <linux/string.h>
24 * Alexey Kuznetsov SMP races, threading, cleanup.
25 * Patrick McHardy LRU queue of frag heads for evictor.
26 * Mitsuru KANDA @USAGI Register inet6_protocol{}.
27 * David Stevens and
28 * YOSHIFUJI,H. @USAGI Always remove fragment header to
29 * calculate ICV correctly.
30 */
31#include <linux/config.h>
32#include <linux/errno.h>
33#include <linux/types.h>
34#include <linux/string.h>
35#include <linux/socket.h>
36#include <linux/sockios.h>
37#include <linux/jiffies.h>
38#include <linux/net.h>
39#include <linux/list.h>
40#include <linux/netdevice.h>
41#include <linux/in6.h>
42#include <linux/ipv6.h>
43#include <linux/icmpv6.h>
44#include <linux/random.h>
45#include <linux/jhash.h>
46
47#include <net/sock.h>
48#include <net/snmp.h>
49
50#include <net/ipv6.h>
51#include <net/protocol.h>
52#include <net/transp_v6.h>
53#include <net/rawv6.h>
54#include <net/ndisc.h>
55#include <net/addrconf.h>
56
57int sysctl_ip6frag_high_thresh = 256*1024;
58int sysctl_ip6frag_low_thresh = 192*1024;
59
60int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT;
61
62struct ip6frag_skb_cb
63{
64 struct inet6_skb_parm h;
65 int offset;
66};
67
68#define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb))
69
70
71/*
72 * Equivalent of ipv4 struct ipq
73 */
74
75struct frag_queue
76{
77 struct frag_queue *next;
78 struct list_head lru_list; /* lru list member */
79
80 __u32 id; /* fragment id */
81 struct in6_addr saddr;
82 struct in6_addr daddr;
83
84 spinlock_t lock;
85 atomic_t refcnt;
86 struct timer_list timer; /* expire timer */
87 struct sk_buff *fragments;
88 int len;
89 int meat;
90 int iif;
91 struct timeval stamp;
92 unsigned int csum;
93 __u8 last_in; /* has first/last segment arrived? */
94#define COMPLETE 4
95#define FIRST_IN 2
96#define LAST_IN 1
97 __u16 nhoffset;
98 struct frag_queue **pprev;
99};
100
101/* Hash table. */
102
103#define IP6Q_HASHSZ 64
104
105static struct frag_queue *ip6_frag_hash[IP6Q_HASHSZ];
106static DEFINE_RWLOCK(ip6_frag_lock);
107static u32 ip6_frag_hash_rnd;
108static LIST_HEAD(ip6_frag_lru_list);
109int ip6_frag_nqueues = 0;
110
111static __inline__ void __fq_unlink(struct frag_queue *fq)
112{
113 if(fq->next)
114 fq->next->pprev = fq->pprev;
115 *fq->pprev = fq->next;
116 list_del(&fq->lru_list);
117 ip6_frag_nqueues--;
118}
119
120static __inline__ void fq_unlink(struct frag_queue *fq)
121{
122 write_lock(&ip6_frag_lock);
123 __fq_unlink(fq);
124 write_unlock(&ip6_frag_lock);
125}
126
127static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr,
128 struct in6_addr *daddr)
129{
130 u32 a, b, c;
131
132 a = saddr->s6_addr32[0];
133 b = saddr->s6_addr32[1];
134 c = saddr->s6_addr32[2];
135
136 a += JHASH_GOLDEN_RATIO;
137 b += JHASH_GOLDEN_RATIO;
138 c += ip6_frag_hash_rnd;
139 __jhash_mix(a, b, c);
140
141 a += saddr->s6_addr32[3];
142 b += daddr->s6_addr32[0];
143 c += daddr->s6_addr32[1];
144 __jhash_mix(a, b, c);
145
146 a += daddr->s6_addr32[2];
147 b += daddr->s6_addr32[3];
148 c += id;
149 __jhash_mix(a, b, c);
150
151 return c & (IP6Q_HASHSZ - 1);
152}
153
154static struct timer_list ip6_frag_secret_timer;
155int sysctl_ip6frag_secret_interval = 10 * 60 * HZ;
156
157static void ip6_frag_secret_rebuild(unsigned long dummy)
158{
159 unsigned long now = jiffies;
160 int i;
161
162 write_lock(&ip6_frag_lock);
163 get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
164 for (i = 0; i < IP6Q_HASHSZ; i++) {
165 struct frag_queue *q;
166
167 q = ip6_frag_hash[i];
168 while (q) {
169 struct frag_queue *next = q->next;
170 unsigned int hval = ip6qhashfn(q->id,
171 &q->saddr,
172 &q->daddr);
173
174 if (hval != i) {
175 /* Unlink. */
176 if (q->next)
177 q->next->pprev = q->pprev;
178 *q->pprev = q->next;
179
180 /* Relink to new hash chain. */
181 if ((q->next = ip6_frag_hash[hval]) != NULL)
182 q->next->pprev = &q->next;
183 ip6_frag_hash[hval] = q;
184 q->pprev = &ip6_frag_hash[hval];
185 }
186
187 q = next;
188 }
189 }
190 write_unlock(&ip6_frag_lock);
191
192 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
193}
194
195atomic_t ip6_frag_mem = ATOMIC_INIT(0);
196
197/* Memory Tracking Functions. */
198static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
199{
200 if (work)
201 *work -= skb->truesize;
202 atomic_sub(skb->truesize, &ip6_frag_mem);
203 kfree_skb(skb);
204}
205
206static inline void frag_free_queue(struct frag_queue *fq, int *work)
207{
208 if (work)
209 *work -= sizeof(struct frag_queue);
210 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
211 kfree(fq);
212}
213
214static inline struct frag_queue *frag_alloc_queue(void)
215{
216 struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC);
217
218 if(!fq)
219 return NULL;
220 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
221 return fq;
222}
223
224/* Destruction primitives. */
225
226/* Complete destruction of fq. */
227static void ip6_frag_destroy(struct frag_queue *fq, int *work)
228{
229 struct sk_buff *fp;
230
231 BUG_TRAP(fq->last_in&COMPLETE);
232 BUG_TRAP(del_timer(&fq->timer) == 0);
233
234 /* Release all fragment data. */
235 fp = fq->fragments;
236 while (fp) {
237 struct sk_buff *xp = fp->next;
238
239 frag_kfree_skb(fp, work);
240 fp = xp;
241 }
242
243 frag_free_queue(fq, work);
244}
245
246static __inline__ void fq_put(struct frag_queue *fq, int *work)
247{
248 if (atomic_dec_and_test(&fq->refcnt))
249 ip6_frag_destroy(fq, work);
250}
251
252/* Kill fq entry. It is not destroyed immediately,
253 * because caller (and someone more) holds reference count.
254 */
255static __inline__ void fq_kill(struct frag_queue *fq)
256{
257 if (del_timer(&fq->timer))
258 atomic_dec(&fq->refcnt);
259
260 if (!(fq->last_in & COMPLETE)) {
261 fq_unlink(fq);
262 atomic_dec(&fq->refcnt);
263 fq->last_in |= COMPLETE;
264 }
265}
266
267static void ip6_evictor(void)
268{
269 struct frag_queue *fq;
270 struct list_head *tmp;
271 int work;
272
273 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
274 if (work <= 0)
275 return;
276
277 while(work > 0) {
278 read_lock(&ip6_frag_lock);
279 if (list_empty(&ip6_frag_lru_list)) {
280 read_unlock(&ip6_frag_lock);
281 return;
282 }
283 tmp = ip6_frag_lru_list.next;
284 fq = list_entry(tmp, struct frag_queue, lru_list);
285 atomic_inc(&fq->refcnt);
286 read_unlock(&ip6_frag_lock);
287
288 spin_lock(&fq->lock);
289 if (!(fq->last_in&COMPLETE))
290 fq_kill(fq);
291 spin_unlock(&fq->lock);
292
293 fq_put(fq, &work);
294 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
295 }
296}
297
298static void ip6_frag_expire(unsigned long data)
299{
300 struct frag_queue *fq = (struct frag_queue *) data;
301
302 spin_lock(&fq->lock);
303
304 if (fq->last_in & COMPLETE)
305 goto out;
306
307 fq_kill(fq);
308
309 IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
310 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
311
312 /* Send error only if the first segment arrived. */
313 if (fq->last_in&FIRST_IN && fq->fragments) {
314 struct net_device *dev = dev_get_by_index(fq->iif);
315
316 /*
317 But use as source device on which LAST ARRIVED
318 segment was received. And do not use fq->dev
319 pointer directly, device might already disappeared.
320 */
321 if (dev) {
322 fq->fragments->dev = dev;
323 icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0,
324 dev);
325 dev_put(dev);
326 }
327 }
328out:
329 spin_unlock(&fq->lock);
330 fq_put(fq, NULL);
331}
332
333/* Creation primitives. */
334
335
336static struct frag_queue *ip6_frag_intern(unsigned int hash,
337 struct frag_queue *fq_in)
338{
339 struct frag_queue *fq;
340
341 write_lock(&ip6_frag_lock);
342#ifdef CONFIG_SMP
343 for (fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
344 if (fq->id == fq_in->id &&
345 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
346 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
347 atomic_inc(&fq->refcnt);
348 write_unlock(&ip6_frag_lock);
349 fq_in->last_in |= COMPLETE;
350 fq_put(fq_in, NULL);
351 return fq;
352 }
353 }
354#endif
355 fq = fq_in;
356
357 if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
358 atomic_inc(&fq->refcnt);
359
360 atomic_inc(&fq->refcnt);
361 if((fq->next = ip6_frag_hash[hash]) != NULL)
362 fq->next->pprev = &fq->next;
363 ip6_frag_hash[hash] = fq;
364 fq->pprev = &ip6_frag_hash[hash];
365 INIT_LIST_HEAD(&fq->lru_list);
366 list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
367 ip6_frag_nqueues++;
368 write_unlock(&ip6_frag_lock);
369 return fq;
370}
371
372
373static struct frag_queue *
374ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
375{
376 struct frag_queue *fq;
377
378 if ((fq = frag_alloc_queue()) == NULL)
379 goto oom;
380
381 memset(fq, 0, sizeof(struct frag_queue));
382
383 fq->id = id;
384 ipv6_addr_copy(&fq->saddr, src);
385 ipv6_addr_copy(&fq->daddr, dst);
386
387 init_timer(&fq->timer);
388 fq->timer.function = ip6_frag_expire;
389 fq->timer.data = (long) fq;
390 spin_lock_init(&fq->lock);
391 atomic_set(&fq->refcnt, 1);
392
393 return ip6_frag_intern(hash, fq);
394
395oom:
396 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
397 return NULL;
398}
399
400static __inline__ struct frag_queue *
401fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
402{
403 struct frag_queue *fq;
404 unsigned int hash = ip6qhashfn(id, src, dst);
405
406 read_lock(&ip6_frag_lock);
407 for(fq = ip6_frag_hash[hash]; fq; fq = fq->next) {
408 if (fq->id == id &&
409 ipv6_addr_equal(src, &fq->saddr) &&
410 ipv6_addr_equal(dst, &fq->daddr)) {
411 atomic_inc(&fq->refcnt);
412 read_unlock(&ip6_frag_lock);
413 return fq;
414 }
415 }
416 read_unlock(&ip6_frag_lock);
417
418 return ip6_frag_create(hash, id, src, dst);
419}
420
421
422static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
423 struct frag_hdr *fhdr, int nhoff)
424{
425 struct sk_buff *prev, *next;
426 int offset, end;
427
428 if (fq->last_in & COMPLETE)
429 goto err;
430
431 offset = ntohs(fhdr->frag_off) & ~0x7;
432 end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
433 ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
434
435 if ((unsigned int)end > IPV6_MAXPLEN) {
436 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
437 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
438 return;
439 }
440
441 if (skb->ip_summed == CHECKSUM_HW)
442 skb->csum = csum_sub(skb->csum,
443 csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
444
445 /* Is this the final fragment? */
446 if (!(fhdr->frag_off & htons(IP6_MF))) {
447 /* If we already have some bits beyond end
448 * or have different end, the segment is corrupted.
449 */
450 if (end < fq->len ||
451 ((fq->last_in & LAST_IN) && end != fq->len))
452 goto err;
453 fq->last_in |= LAST_IN;
454 fq->len = end;
455 } else {
456 /* Check if the fragment is rounded to 8 bytes.
457 * Required by the RFC.
458 */
459 if (end & 0x7) {
460 /* RFC2460 says always send parameter problem in
461 * this case. -DaveM
462 */
463 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
464 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
465 offsetof(struct ipv6hdr, payload_len));
466 return;
467 }
468 if (end > fq->len) {
469 /* Some bits beyond end -> corruption. */
470 if (fq->last_in & LAST_IN)
471 goto err;
472 fq->len = end;
473 }
474 }
475
476 if (end == offset)
477 goto err;
478
479 /* Point into the IP datagram 'data' part. */
480 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
481 goto err;
Stephen Hemminger42ca89c2005-09-08 12:57:43 -0700482
483 if (pskb_trim_rcsum(skb, end - offset))
484 goto err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485
486 /* Find out which fragments are in front and at the back of us
487 * in the chain of fragments so far. We must know where to put
488 * this fragment, right?
489 */
490 prev = NULL;
491 for(next = fq->fragments; next != NULL; next = next->next) {
492 if (FRAG6_CB(next)->offset >= offset)
493 break; /* bingo! */
494 prev = next;
495 }
496
497 /* We found where to put this one. Check for overlap with
498 * preceding fragment, and, if needed, align things so that
499 * any overlaps are eliminated.
500 */
501 if (prev) {
502 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
503
504 if (i > 0) {
505 offset += i;
506 if (end <= offset)
507 goto err;
508 if (!pskb_pull(skb, i))
509 goto err;
510 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
511 skb->ip_summed = CHECKSUM_NONE;
512 }
513 }
514
515 /* Look for overlap with succeeding segments.
516 * If we can merge fragments, do it.
517 */
518 while (next && FRAG6_CB(next)->offset < end) {
519 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
520
521 if (i < next->len) {
522 /* Eat head of the next overlapped fragment
523 * and leave the loop. The next ones cannot overlap.
524 */
525 if (!pskb_pull(next, i))
526 goto err;
527 FRAG6_CB(next)->offset += i; /* next fragment */
528 fq->meat -= i;
529 if (next->ip_summed != CHECKSUM_UNNECESSARY)
530 next->ip_summed = CHECKSUM_NONE;
531 break;
532 } else {
533 struct sk_buff *free_it = next;
534
535 /* Old fragment is completely overridden with
536 * new one drop it.
537 */
538 next = next->next;
539
540 if (prev)
541 prev->next = next;
542 else
543 fq->fragments = next;
544
545 fq->meat -= free_it->len;
546 frag_kfree_skb(free_it, NULL);
547 }
548 }
549
550 FRAG6_CB(skb)->offset = offset;
551
552 /* Insert this fragment in the chain of fragments. */
553 skb->next = next;
554 if (prev)
555 prev->next = skb;
556 else
557 fq->fragments = skb;
558
559 if (skb->dev)
560 fq->iif = skb->dev->ifindex;
561 skb->dev = NULL;
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700562 skb_get_timestamp(skb, &fq->stamp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 fq->meat += skb->len;
564 atomic_add(skb->truesize, &ip6_frag_mem);
565
566 /* The first fragment.
567 * nhoffset is obtained from the first fragment, of course.
568 */
569 if (offset == 0) {
570 fq->nhoffset = nhoff;
571 fq->last_in |= FIRST_IN;
572 }
573 write_lock(&ip6_frag_lock);
574 list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
575 write_unlock(&ip6_frag_lock);
576 return;
577
578err:
579 IP6_INC_STATS(IPSTATS_MIB_REASMFAILS);
580 kfree_skb(skb);
581}
582
583/*
584 * Check if this packet is complete.
585 * Returns NULL on failure by any reason, and pointer
586 * to current nexthdr field in reassembled frame.
587 *
588 * It is called with locked fq, and caller must check that
589 * queue is eligible for reassembly i.e. it is not COMPLETE,
590 * the last and the first frames arrived and all the bits are here.
591 */
592static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
593 unsigned int *nhoffp,
594 struct net_device *dev)
595{
596 struct sk_buff *fp, *head = fq->fragments;
597 int payload_len;
598 unsigned int nhoff;
599
600 fq_kill(fq);
601
602 BUG_TRAP(head != NULL);
603 BUG_TRAP(FRAG6_CB(head)->offset == 0);
604
605 /* Unfragmented part is taken from the first segment. */
606 payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
607 if (payload_len > IPV6_MAXPLEN)
608 goto out_oversize;
609
610 /* Head of list must not be cloned. */
611 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
612 goto out_oom;
613
614 /* If the first fragment is fragmented itself, we split
615 * it to two chunks: the first with data and paged part
616 * and the second, holding only fragments. */
617 if (skb_shinfo(head)->frag_list) {
618 struct sk_buff *clone;
619 int i, plen = 0;
620
621 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
622 goto out_oom;
623 clone->next = head->next;
624 head->next = clone;
625 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
626 skb_shinfo(head)->frag_list = NULL;
627 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
628 plen += skb_shinfo(head)->frags[i].size;
629 clone->len = clone->data_len = head->data_len - plen;
630 head->data_len -= clone->len;
631 head->len -= clone->len;
632 clone->csum = 0;
633 clone->ip_summed = head->ip_summed;
634 atomic_add(clone->truesize, &ip6_frag_mem);
635 }
636
637 /* We have to remove fragment header from datagram and to relocate
638 * header in order to calculate ICV correctly. */
639 nhoff = fq->nhoffset;
640 head->nh.raw[nhoff] = head->h.raw[0];
641 memmove(head->head + sizeof(struct frag_hdr), head->head,
642 (head->data - head->head) - sizeof(struct frag_hdr));
643 head->mac.raw += sizeof(struct frag_hdr);
644 head->nh.raw += sizeof(struct frag_hdr);
645
646 skb_shinfo(head)->frag_list = head->next;
647 head->h.raw = head->data;
648 skb_push(head, head->data - head->nh.raw);
649 atomic_sub(head->truesize, &ip6_frag_mem);
650
651 for (fp=head->next; fp; fp = fp->next) {
652 head->data_len += fp->len;
653 head->len += fp->len;
654 if (head->ip_summed != fp->ip_summed)
655 head->ip_summed = CHECKSUM_NONE;
656 else if (head->ip_summed == CHECKSUM_HW)
657 head->csum = csum_add(head->csum, fp->csum);
658 head->truesize += fp->truesize;
659 atomic_sub(fp->truesize, &ip6_frag_mem);
660 }
661
662 head->next = NULL;
663 head->dev = dev;
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700664 skb_set_timestamp(head, &fq->stamp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 head->nh.ipv6h->payload_len = htons(payload_len);
666
667 *skb_in = head;
668
669 /* Yes, and fold redundant checksum back. 8) */
670 if (head->ip_summed == CHECKSUM_HW)
671 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
672
673 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
674 fq->fragments = NULL;
675 *nhoffp = nhoff;
676 return 1;
677
678out_oversize:
679 if (net_ratelimit())
680 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
681 goto out_fail;
682out_oom:
683 if (net_ratelimit())
684 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
685out_fail:
686 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
687 return -1;
688}
689
690static int ipv6_frag_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
691{
692 struct sk_buff *skb = *skbp;
693 struct net_device *dev = skb->dev;
694 struct frag_hdr *fhdr;
695 struct frag_queue *fq;
696 struct ipv6hdr *hdr;
697
698 hdr = skb->nh.ipv6h;
699
700 IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
701
702 /* Jumbo payload inhibits frag. header */
703 if (hdr->payload_len==0) {
704 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
705 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
706 return -1;
707 }
708 if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
709 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
710 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
711 return -1;
712 }
713
714 hdr = skb->nh.ipv6h;
715 fhdr = (struct frag_hdr *)skb->h.raw;
716
717 if (!(fhdr->frag_off & htons(0xFFF9))) {
718 /* It is not a fragmented frame */
719 skb->h.raw += sizeof(struct frag_hdr);
720 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
721
722 *nhoffp = (u8*)fhdr - skb->nh.raw;
723 return 1;
724 }
725
726 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
727 ip6_evictor();
728
729 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
730 int ret = -1;
731
732 spin_lock(&fq->lock);
733
734 ip6_frag_queue(fq, skb, fhdr, *nhoffp);
735
736 if (fq->last_in == (FIRST_IN|LAST_IN) &&
737 fq->meat == fq->len)
738 ret = ip6_frag_reasm(fq, skbp, nhoffp, dev);
739
740 spin_unlock(&fq->lock);
741 fq_put(fq, NULL);
742 return ret;
743 }
744
745 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
746 kfree_skb(skb);
747 return -1;
748}
749
750static struct inet6_protocol frag_protocol =
751{
752 .handler = ipv6_frag_rcv,
753 .flags = INET6_PROTO_NOPOLICY,
754};
755
756void __init ipv6_frag_init(void)
757{
758 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
759 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
760
761 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
762 (jiffies ^ (jiffies >> 6)));
763
764 init_timer(&ip6_frag_secret_timer);
765 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
766 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
767 add_timer(&ip6_frag_secret_timer);
768}