blob: 15e1456b3f18731f8a5bdc35048845b37d549262 [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{
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -080077 struct hlist_node list;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098};
99
100/* Hash table. */
101
102#define IP6Q_HASHSZ 64
103
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800104static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105static DEFINE_RWLOCK(ip6_frag_lock);
106static u32 ip6_frag_hash_rnd;
107static LIST_HEAD(ip6_frag_lru_list);
108int ip6_frag_nqueues = 0;
109
110static __inline__ void __fq_unlink(struct frag_queue *fq)
111{
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800112 hlist_del(&fq->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 list_del(&fq->lru_list);
114 ip6_frag_nqueues--;
115}
116
117static __inline__ void fq_unlink(struct frag_queue *fq)
118{
119 write_lock(&ip6_frag_lock);
120 __fq_unlink(fq);
121 write_unlock(&ip6_frag_lock);
122}
123
124static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr,
125 struct in6_addr *daddr)
126{
127 u32 a, b, c;
128
129 a = saddr->s6_addr32[0];
130 b = saddr->s6_addr32[1];
131 c = saddr->s6_addr32[2];
132
133 a += JHASH_GOLDEN_RATIO;
134 b += JHASH_GOLDEN_RATIO;
135 c += ip6_frag_hash_rnd;
136 __jhash_mix(a, b, c);
137
138 a += saddr->s6_addr32[3];
139 b += daddr->s6_addr32[0];
140 c += daddr->s6_addr32[1];
141 __jhash_mix(a, b, c);
142
143 a += daddr->s6_addr32[2];
144 b += daddr->s6_addr32[3];
145 c += id;
146 __jhash_mix(a, b, c);
147
148 return c & (IP6Q_HASHSZ - 1);
149}
150
151static struct timer_list ip6_frag_secret_timer;
152int sysctl_ip6frag_secret_interval = 10 * 60 * HZ;
153
154static void ip6_frag_secret_rebuild(unsigned long dummy)
155{
156 unsigned long now = jiffies;
157 int i;
158
159 write_lock(&ip6_frag_lock);
160 get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
161 for (i = 0; i < IP6Q_HASHSZ; i++) {
162 struct frag_queue *q;
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800163 struct hlist_node *p, *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800165 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 unsigned int hval = ip6qhashfn(q->id,
167 &q->saddr,
168 &q->daddr);
169
170 if (hval != i) {
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800171 hlist_del(&q->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
173 /* Relink to new hash chain. */
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800174 hlist_add_head(&q->list,
175 &ip6_frag_hash[hval]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800177 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 }
179 }
180 write_unlock(&ip6_frag_lock);
181
182 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
183}
184
185atomic_t ip6_frag_mem = ATOMIC_INIT(0);
186
187/* Memory Tracking Functions. */
188static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
189{
190 if (work)
191 *work -= skb->truesize;
192 atomic_sub(skb->truesize, &ip6_frag_mem);
193 kfree_skb(skb);
194}
195
196static inline void frag_free_queue(struct frag_queue *fq, int *work)
197{
198 if (work)
199 *work -= sizeof(struct frag_queue);
200 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
201 kfree(fq);
202}
203
204static inline struct frag_queue *frag_alloc_queue(void)
205{
206 struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC);
207
208 if(!fq)
209 return NULL;
210 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
211 return fq;
212}
213
214/* Destruction primitives. */
215
216/* Complete destruction of fq. */
217static void ip6_frag_destroy(struct frag_queue *fq, int *work)
218{
219 struct sk_buff *fp;
220
221 BUG_TRAP(fq->last_in&COMPLETE);
222 BUG_TRAP(del_timer(&fq->timer) == 0);
223
224 /* Release all fragment data. */
225 fp = fq->fragments;
226 while (fp) {
227 struct sk_buff *xp = fp->next;
228
229 frag_kfree_skb(fp, work);
230 fp = xp;
231 }
232
233 frag_free_queue(fq, work);
234}
235
236static __inline__ void fq_put(struct frag_queue *fq, int *work)
237{
238 if (atomic_dec_and_test(&fq->refcnt))
239 ip6_frag_destroy(fq, work);
240}
241
242/* Kill fq entry. It is not destroyed immediately,
243 * because caller (and someone more) holds reference count.
244 */
245static __inline__ void fq_kill(struct frag_queue *fq)
246{
247 if (del_timer(&fq->timer))
248 atomic_dec(&fq->refcnt);
249
250 if (!(fq->last_in & COMPLETE)) {
251 fq_unlink(fq);
252 atomic_dec(&fq->refcnt);
253 fq->last_in |= COMPLETE;
254 }
255}
256
257static void ip6_evictor(void)
258{
259 struct frag_queue *fq;
260 struct list_head *tmp;
261 int work;
262
263 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
264 if (work <= 0)
265 return;
266
267 while(work > 0) {
268 read_lock(&ip6_frag_lock);
269 if (list_empty(&ip6_frag_lru_list)) {
270 read_unlock(&ip6_frag_lock);
271 return;
272 }
273 tmp = ip6_frag_lru_list.next;
274 fq = list_entry(tmp, struct frag_queue, lru_list);
275 atomic_inc(&fq->refcnt);
276 read_unlock(&ip6_frag_lock);
277
278 spin_lock(&fq->lock);
279 if (!(fq->last_in&COMPLETE))
280 fq_kill(fq);
281 spin_unlock(&fq->lock);
282
283 fq_put(fq, &work);
284 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
285 }
286}
287
288static void ip6_frag_expire(unsigned long data)
289{
290 struct frag_queue *fq = (struct frag_queue *) data;
291
292 spin_lock(&fq->lock);
293
294 if (fq->last_in & COMPLETE)
295 goto out;
296
297 fq_kill(fq);
298
299 IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
300 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
301
302 /* Send error only if the first segment arrived. */
303 if (fq->last_in&FIRST_IN && fq->fragments) {
304 struct net_device *dev = dev_get_by_index(fq->iif);
305
306 /*
307 But use as source device on which LAST ARRIVED
308 segment was received. And do not use fq->dev
309 pointer directly, device might already disappeared.
310 */
311 if (dev) {
312 fq->fragments->dev = dev;
313 icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0,
314 dev);
315 dev_put(dev);
316 }
317 }
318out:
319 spin_unlock(&fq->lock);
320 fq_put(fq, NULL);
321}
322
323/* Creation primitives. */
324
325
326static struct frag_queue *ip6_frag_intern(unsigned int hash,
327 struct frag_queue *fq_in)
328{
329 struct frag_queue *fq;
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800330#ifdef CONFIG_SMP
331 struct hlist_node *n;
332#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
334 write_lock(&ip6_frag_lock);
335#ifdef CONFIG_SMP
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800336 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 if (fq->id == fq_in->id &&
338 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
339 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
340 atomic_inc(&fq->refcnt);
341 write_unlock(&ip6_frag_lock);
342 fq_in->last_in |= COMPLETE;
343 fq_put(fq_in, NULL);
344 return fq;
345 }
346 }
347#endif
348 fq = fq_in;
349
350 if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
351 atomic_inc(&fq->refcnt);
352
353 atomic_inc(&fq->refcnt);
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800354 hlist_add_head(&fq->list, &ip6_frag_hash[hash]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 INIT_LIST_HEAD(&fq->lru_list);
356 list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
357 ip6_frag_nqueues++;
358 write_unlock(&ip6_frag_lock);
359 return fq;
360}
361
362
363static struct frag_queue *
364ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst)
365{
366 struct frag_queue *fq;
367
368 if ((fq = frag_alloc_queue()) == NULL)
369 goto oom;
370
371 memset(fq, 0, sizeof(struct frag_queue));
372
373 fq->id = id;
374 ipv6_addr_copy(&fq->saddr, src);
375 ipv6_addr_copy(&fq->daddr, dst);
376
377 init_timer(&fq->timer);
378 fq->timer.function = ip6_frag_expire;
379 fq->timer.data = (long) fq;
380 spin_lock_init(&fq->lock);
381 atomic_set(&fq->refcnt, 1);
382
383 return ip6_frag_intern(hash, fq);
384
385oom:
386 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
387 return NULL;
388}
389
390static __inline__ struct frag_queue *
391fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
392{
393 struct frag_queue *fq;
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800394 struct hlist_node *n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 unsigned int hash = ip6qhashfn(id, src, dst);
396
397 read_lock(&ip6_frag_lock);
Yasuyuki Kozakaie7c8a412005-11-16 12:55:37 -0800398 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 if (fq->id == id &&
400 ipv6_addr_equal(src, &fq->saddr) &&
401 ipv6_addr_equal(dst, &fq->daddr)) {
402 atomic_inc(&fq->refcnt);
403 read_unlock(&ip6_frag_lock);
404 return fq;
405 }
406 }
407 read_unlock(&ip6_frag_lock);
408
409 return ip6_frag_create(hash, id, src, dst);
410}
411
412
413static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
414 struct frag_hdr *fhdr, int nhoff)
415{
416 struct sk_buff *prev, *next;
417 int offset, end;
418
419 if (fq->last_in & COMPLETE)
420 goto err;
421
422 offset = ntohs(fhdr->frag_off) & ~0x7;
423 end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
424 ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
425
426 if ((unsigned int)end > IPV6_MAXPLEN) {
427 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
428 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
429 return;
430 }
431
432 if (skb->ip_summed == CHECKSUM_HW)
433 skb->csum = csum_sub(skb->csum,
434 csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
435
436 /* Is this the final fragment? */
437 if (!(fhdr->frag_off & htons(IP6_MF))) {
438 /* If we already have some bits beyond end
439 * or have different end, the segment is corrupted.
440 */
441 if (end < fq->len ||
442 ((fq->last_in & LAST_IN) && end != fq->len))
443 goto err;
444 fq->last_in |= LAST_IN;
445 fq->len = end;
446 } else {
447 /* Check if the fragment is rounded to 8 bytes.
448 * Required by the RFC.
449 */
450 if (end & 0x7) {
451 /* RFC2460 says always send parameter problem in
452 * this case. -DaveM
453 */
454 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
455 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
456 offsetof(struct ipv6hdr, payload_len));
457 return;
458 }
459 if (end > fq->len) {
460 /* Some bits beyond end -> corruption. */
461 if (fq->last_in & LAST_IN)
462 goto err;
463 fq->len = end;
464 }
465 }
466
467 if (end == offset)
468 goto err;
469
470 /* Point into the IP datagram 'data' part. */
471 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
472 goto err;
Stephen Hemminger42ca89c2005-09-08 12:57:43 -0700473
474 if (pskb_trim_rcsum(skb, end - offset))
475 goto err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
477 /* Find out which fragments are in front and at the back of us
478 * in the chain of fragments so far. We must know where to put
479 * this fragment, right?
480 */
481 prev = NULL;
482 for(next = fq->fragments; next != NULL; next = next->next) {
483 if (FRAG6_CB(next)->offset >= offset)
484 break; /* bingo! */
485 prev = next;
486 }
487
488 /* We found where to put this one. Check for overlap with
489 * preceding fragment, and, if needed, align things so that
490 * any overlaps are eliminated.
491 */
492 if (prev) {
493 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
494
495 if (i > 0) {
496 offset += i;
497 if (end <= offset)
498 goto err;
499 if (!pskb_pull(skb, i))
500 goto err;
501 if (skb->ip_summed != CHECKSUM_UNNECESSARY)
502 skb->ip_summed = CHECKSUM_NONE;
503 }
504 }
505
506 /* Look for overlap with succeeding segments.
507 * If we can merge fragments, do it.
508 */
509 while (next && FRAG6_CB(next)->offset < end) {
510 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
511
512 if (i < next->len) {
513 /* Eat head of the next overlapped fragment
514 * and leave the loop. The next ones cannot overlap.
515 */
516 if (!pskb_pull(next, i))
517 goto err;
518 FRAG6_CB(next)->offset += i; /* next fragment */
519 fq->meat -= i;
520 if (next->ip_summed != CHECKSUM_UNNECESSARY)
521 next->ip_summed = CHECKSUM_NONE;
522 break;
523 } else {
524 struct sk_buff *free_it = next;
525
526 /* Old fragment is completely overridden with
527 * new one drop it.
528 */
529 next = next->next;
530
531 if (prev)
532 prev->next = next;
533 else
534 fq->fragments = next;
535
536 fq->meat -= free_it->len;
537 frag_kfree_skb(free_it, NULL);
538 }
539 }
540
541 FRAG6_CB(skb)->offset = offset;
542
543 /* Insert this fragment in the chain of fragments. */
544 skb->next = next;
545 if (prev)
546 prev->next = skb;
547 else
548 fq->fragments = skb;
549
550 if (skb->dev)
551 fq->iif = skb->dev->ifindex;
552 skb->dev = NULL;
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700553 skb_get_timestamp(skb, &fq->stamp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 fq->meat += skb->len;
555 atomic_add(skb->truesize, &ip6_frag_mem);
556
557 /* The first fragment.
558 * nhoffset is obtained from the first fragment, of course.
559 */
560 if (offset == 0) {
561 fq->nhoffset = nhoff;
562 fq->last_in |= FIRST_IN;
563 }
564 write_lock(&ip6_frag_lock);
565 list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
566 write_unlock(&ip6_frag_lock);
567 return;
568
569err:
570 IP6_INC_STATS(IPSTATS_MIB_REASMFAILS);
571 kfree_skb(skb);
572}
573
574/*
575 * Check if this packet is complete.
576 * Returns NULL on failure by any reason, and pointer
577 * to current nexthdr field in reassembled frame.
578 *
579 * It is called with locked fq, and caller must check that
580 * queue is eligible for reassembly i.e. it is not COMPLETE,
581 * the last and the first frames arrived and all the bits are here.
582 */
583static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 struct net_device *dev)
585{
586 struct sk_buff *fp, *head = fq->fragments;
587 int payload_len;
588 unsigned int nhoff;
589
590 fq_kill(fq);
591
592 BUG_TRAP(head != NULL);
593 BUG_TRAP(FRAG6_CB(head)->offset == 0);
594
595 /* Unfragmented part is taken from the first segment. */
596 payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
597 if (payload_len > IPV6_MAXPLEN)
598 goto out_oversize;
599
600 /* Head of list must not be cloned. */
601 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
602 goto out_oom;
603
604 /* If the first fragment is fragmented itself, we split
605 * it to two chunks: the first with data and paged part
606 * and the second, holding only fragments. */
607 if (skb_shinfo(head)->frag_list) {
608 struct sk_buff *clone;
609 int i, plen = 0;
610
611 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
612 goto out_oom;
613 clone->next = head->next;
614 head->next = clone;
615 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
616 skb_shinfo(head)->frag_list = NULL;
617 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
618 plen += skb_shinfo(head)->frags[i].size;
619 clone->len = clone->data_len = head->data_len - plen;
620 head->data_len -= clone->len;
621 head->len -= clone->len;
622 clone->csum = 0;
623 clone->ip_summed = head->ip_summed;
624 atomic_add(clone->truesize, &ip6_frag_mem);
625 }
626
627 /* We have to remove fragment header from datagram and to relocate
628 * header in order to calculate ICV correctly. */
629 nhoff = fq->nhoffset;
630 head->nh.raw[nhoff] = head->h.raw[0];
631 memmove(head->head + sizeof(struct frag_hdr), head->head,
632 (head->data - head->head) - sizeof(struct frag_hdr));
633 head->mac.raw += sizeof(struct frag_hdr);
634 head->nh.raw += sizeof(struct frag_hdr);
635
636 skb_shinfo(head)->frag_list = head->next;
637 head->h.raw = head->data;
638 skb_push(head, head->data - head->nh.raw);
639 atomic_sub(head->truesize, &ip6_frag_mem);
640
641 for (fp=head->next; fp; fp = fp->next) {
642 head->data_len += fp->len;
643 head->len += fp->len;
644 if (head->ip_summed != fp->ip_summed)
645 head->ip_summed = CHECKSUM_NONE;
646 else if (head->ip_summed == CHECKSUM_HW)
647 head->csum = csum_add(head->csum, fp->csum);
648 head->truesize += fp->truesize;
649 atomic_sub(fp->truesize, &ip6_frag_mem);
650 }
651
652 head->next = NULL;
653 head->dev = dev;
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700654 skb_set_timestamp(head, &fq->stamp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 head->nh.ipv6h->payload_len = htons(payload_len);
Patrick McHardy951dbc82006-01-06 23:02:34 -0800656 IP6CB(head)->nhoff = nhoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657
658 *skb_in = head;
659
660 /* Yes, and fold redundant checksum back. 8) */
661 if (head->ip_summed == CHECKSUM_HW)
662 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
663
664 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
665 fq->fragments = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 return 1;
667
668out_oversize:
669 if (net_ratelimit())
670 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
671 goto out_fail;
672out_oom:
673 if (net_ratelimit())
674 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
675out_fail:
676 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
677 return -1;
678}
679
Patrick McHardy951dbc82006-01-06 23:02:34 -0800680static int ipv6_frag_rcv(struct sk_buff **skbp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681{
682 struct sk_buff *skb = *skbp;
683 struct net_device *dev = skb->dev;
684 struct frag_hdr *fhdr;
685 struct frag_queue *fq;
686 struct ipv6hdr *hdr;
687
688 hdr = skb->nh.ipv6h;
689
690 IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
691
692 /* Jumbo payload inhibits frag. header */
693 if (hdr->payload_len==0) {
694 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
695 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
696 return -1;
697 }
698 if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
699 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
700 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
701 return -1;
702 }
703
704 hdr = skb->nh.ipv6h;
705 fhdr = (struct frag_hdr *)skb->h.raw;
706
707 if (!(fhdr->frag_off & htons(0xFFF9))) {
708 /* It is not a fragmented frame */
709 skb->h.raw += sizeof(struct frag_hdr);
710 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
711
Patrick McHardy951dbc82006-01-06 23:02:34 -0800712 IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 return 1;
714 }
715
716 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
717 ip6_evictor();
718
719 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
720 int ret = -1;
721
722 spin_lock(&fq->lock);
723
Patrick McHardy951dbc82006-01-06 23:02:34 -0800724 ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
726 if (fq->last_in == (FIRST_IN|LAST_IN) &&
727 fq->meat == fq->len)
Patrick McHardy951dbc82006-01-06 23:02:34 -0800728 ret = ip6_frag_reasm(fq, skbp, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729
730 spin_unlock(&fq->lock);
731 fq_put(fq, NULL);
732 return ret;
733 }
734
735 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
736 kfree_skb(skb);
737 return -1;
738}
739
740static struct inet6_protocol frag_protocol =
741{
742 .handler = ipv6_frag_rcv,
743 .flags = INET6_PROTO_NOPOLICY,
744};
745
746void __init ipv6_frag_init(void)
747{
748 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
749 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
750
751 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
752 (jiffies ^ (jiffies >> 6)));
753
754 init_timer(&ip6_frag_secret_timer);
755 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
756 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
757 add_timer(&ip6_frag_secret_timer);
758}