156a37fe3ff3e6c25dcc63d0d435bd049f62a466
[linux-2.6.git] / net / ipv6 / reassembly.c
1 /*
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/errno.h>
32 #include <linux/types.h>
33 #include <linux/string.h>
34 #include <linux/socket.h>
35 #include <linux/sockios.h>
36 #include <linux/jiffies.h>
37 #include <linux/net.h>
38 #include <linux/list.h>
39 #include <linux/netdevice.h>
40 #include <linux/in6.h>
41 #include <linux/ipv6.h>
42 #include <linux/icmpv6.h>
43 #include <linux/random.h>
44 #include <linux/jhash.h>
45
46 #include <net/sock.h>
47 #include <net/snmp.h>
48
49 #include <net/ipv6.h>
50 #include <net/ip6_route.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
57 int sysctl_ip6frag_high_thresh __read_mostly = 256*1024;
58 int sysctl_ip6frag_low_thresh __read_mostly = 192*1024;
59
60 int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT;
61
62 struct 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
75 struct frag_queue
76 {
77         struct hlist_node       list;
78         struct list_head lru_list;              /* lru list member      */
79
80         __be32                  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         ktime_t                 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 };
99
100 /* Hash table. */
101
102 #define IP6Q_HASHSZ     64
103
104 static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ];
105 static DEFINE_RWLOCK(ip6_frag_lock);
106 static u32 ip6_frag_hash_rnd;
107 static LIST_HEAD(ip6_frag_lru_list);
108 int ip6_frag_nqueues = 0;
109
110 static __inline__ void __fq_unlink(struct frag_queue *fq)
111 {
112         hlist_del(&fq->list);
113         list_del(&fq->lru_list);
114         ip6_frag_nqueues--;
115 }
116
117 static __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
124 /*
125  * callers should be careful not to use the hash value outside the ipfrag_lock
126  * as doing so could race with ipfrag_hash_rnd being recalculated.
127  */
128 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr,
129                                struct in6_addr *daddr)
130 {
131         u32 a, b, c;
132
133         a = (__force u32)saddr->s6_addr32[0];
134         b = (__force u32)saddr->s6_addr32[1];
135         c = (__force u32)saddr->s6_addr32[2];
136
137         a += JHASH_GOLDEN_RATIO;
138         b += JHASH_GOLDEN_RATIO;
139         c += ip6_frag_hash_rnd;
140         __jhash_mix(a, b, c);
141
142         a += (__force u32)saddr->s6_addr32[3];
143         b += (__force u32)daddr->s6_addr32[0];
144         c += (__force u32)daddr->s6_addr32[1];
145         __jhash_mix(a, b, c);
146
147         a += (__force u32)daddr->s6_addr32[2];
148         b += (__force u32)daddr->s6_addr32[3];
149         c += (__force u32)id;
150         __jhash_mix(a, b, c);
151
152         return c & (IP6Q_HASHSZ - 1);
153 }
154
155 static struct timer_list ip6_frag_secret_timer;
156 int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ;
157
158 static void ip6_frag_secret_rebuild(unsigned long dummy)
159 {
160         unsigned long now = jiffies;
161         int i;
162
163         write_lock(&ip6_frag_lock);
164         get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32));
165         for (i = 0; i < IP6Q_HASHSZ; i++) {
166                 struct frag_queue *q;
167                 struct hlist_node *p, *n;
168
169                 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) {
170                         unsigned int hval = ip6qhashfn(q->id,
171                                                        &q->saddr,
172                                                        &q->daddr);
173
174                         if (hval != i) {
175                                 hlist_del(&q->list);
176
177                                 /* Relink to new hash chain. */
178                                 hlist_add_head(&q->list,
179                                                &ip6_frag_hash[hval]);
180
181                         }
182                 }
183         }
184         write_unlock(&ip6_frag_lock);
185
186         mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
187 }
188
189 atomic_t ip6_frag_mem = ATOMIC_INIT(0);
190
191 /* Memory Tracking Functions. */
192 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
193 {
194         if (work)
195                 *work -= skb->truesize;
196         atomic_sub(skb->truesize, &ip6_frag_mem);
197         kfree_skb(skb);
198 }
199
200 static inline void frag_free_queue(struct frag_queue *fq, int *work)
201 {
202         if (work)
203                 *work -= sizeof(struct frag_queue);
204         atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
205         kfree(fq);
206 }
207
208 static inline struct frag_queue *frag_alloc_queue(void)
209 {
210         struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC);
211
212         if(!fq)
213                 return NULL;
214         atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
215         return fq;
216 }
217
218 /* Destruction primitives. */
219
220 /* Complete destruction of fq. */
221 static void ip6_frag_destroy(struct frag_queue *fq, int *work)
222 {
223         struct sk_buff *fp;
224
225         BUG_TRAP(fq->last_in&COMPLETE);
226         BUG_TRAP(del_timer(&fq->timer) == 0);
227
228         /* Release all fragment data. */
229         fp = fq->fragments;
230         while (fp) {
231                 struct sk_buff *xp = fp->next;
232
233                 frag_kfree_skb(fp, work);
234                 fp = xp;
235         }
236
237         frag_free_queue(fq, work);
238 }
239
240 static __inline__ void fq_put(struct frag_queue *fq, int *work)
241 {
242         if (atomic_dec_and_test(&fq->refcnt))
243                 ip6_frag_destroy(fq, work);
244 }
245
246 /* Kill fq entry. It is not destroyed immediately,
247  * because caller (and someone more) holds reference count.
248  */
249 static __inline__ void fq_kill(struct frag_queue *fq)
250 {
251         if (del_timer(&fq->timer))
252                 atomic_dec(&fq->refcnt);
253
254         if (!(fq->last_in & COMPLETE)) {
255                 fq_unlink(fq);
256                 atomic_dec(&fq->refcnt);
257                 fq->last_in |= COMPLETE;
258         }
259 }
260
261 static void ip6_evictor(struct inet6_dev *idev)
262 {
263         struct frag_queue *fq;
264         struct list_head *tmp;
265         int work;
266
267         work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
268         if (work <= 0)
269                 return;
270
271         while(work > 0) {
272                 read_lock(&ip6_frag_lock);
273                 if (list_empty(&ip6_frag_lru_list)) {
274                         read_unlock(&ip6_frag_lock);
275                         return;
276                 }
277                 tmp = ip6_frag_lru_list.next;
278                 fq = list_entry(tmp, struct frag_queue, lru_list);
279                 atomic_inc(&fq->refcnt);
280                 read_unlock(&ip6_frag_lock);
281
282                 spin_lock(&fq->lock);
283                 if (!(fq->last_in&COMPLETE))
284                         fq_kill(fq);
285                 spin_unlock(&fq->lock);
286
287                 fq_put(fq, &work);
288                 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
289         }
290 }
291
292 static void ip6_frag_expire(unsigned long data)
293 {
294         struct frag_queue *fq = (struct frag_queue *) data;
295         struct net_device *dev = NULL;
296
297         spin_lock(&fq->lock);
298
299         if (fq->last_in & COMPLETE)
300                 goto out;
301
302         fq_kill(fq);
303
304         dev = dev_get_by_index(fq->iif);
305         if (!dev)
306                 goto out;
307
308         rcu_read_lock();
309         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
310         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
311         rcu_read_unlock();
312
313         /* Don't send error if the first segment did not arrive. */
314         if (!(fq->last_in&FIRST_IN) || !fq->fragments)
315                 goto out;
316
317         /*
318            But use as source device on which LAST ARRIVED
319            segment was received. And do not use fq->dev
320            pointer directly, device might already disappeared.
321          */
322         fq->fragments->dev = dev;
323         icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
324 out:
325         if (dev)
326                 dev_put(dev);
327         spin_unlock(&fq->lock);
328         fq_put(fq, NULL);
329 }
330
331 /* Creation primitives. */
332
333
334 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in)
335 {
336         struct frag_queue *fq;
337         unsigned int hash;
338 #ifdef CONFIG_SMP
339         struct hlist_node *n;
340 #endif
341
342         write_lock(&ip6_frag_lock);
343         hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr);
344 #ifdef CONFIG_SMP
345         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
346                 if (fq->id == fq_in->id &&
347                     ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
348                     ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
349                         atomic_inc(&fq->refcnt);
350                         write_unlock(&ip6_frag_lock);
351                         fq_in->last_in |= COMPLETE;
352                         fq_put(fq_in, NULL);
353                         return fq;
354                 }
355         }
356 #endif
357         fq = fq_in;
358
359         if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
360                 atomic_inc(&fq->refcnt);
361
362         atomic_inc(&fq->refcnt);
363         hlist_add_head(&fq->list, &ip6_frag_hash[hash]);
364         INIT_LIST_HEAD(&fq->lru_list);
365         list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
366         ip6_frag_nqueues++;
367         write_unlock(&ip6_frag_lock);
368         return fq;
369 }
370
371
372 static struct frag_queue *
373 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst,
374                 struct inet6_dev *idev)
375 {
376         struct frag_queue *fq;
377
378         if ((fq = frag_alloc_queue()) == NULL)
379                 goto oom;
380
381         fq->id = id;
382         ipv6_addr_copy(&fq->saddr, src);
383         ipv6_addr_copy(&fq->daddr, dst);
384
385         init_timer(&fq->timer);
386         fq->timer.function = ip6_frag_expire;
387         fq->timer.data = (long) fq;
388         spin_lock_init(&fq->lock);
389         atomic_set(&fq->refcnt, 1);
390
391         return ip6_frag_intern(fq);
392
393 oom:
394         IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS);
395         return NULL;
396 }
397
398 static __inline__ struct frag_queue *
399 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst,
400         struct inet6_dev *idev)
401 {
402         struct frag_queue *fq;
403         struct hlist_node *n;
404         unsigned int hash;
405
406         read_lock(&ip6_frag_lock);
407         hash = ip6qhashfn(id, src, dst);
408         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
409                 if (fq->id == id &&
410                     ipv6_addr_equal(src, &fq->saddr) &&
411                     ipv6_addr_equal(dst, &fq->daddr)) {
412                         atomic_inc(&fq->refcnt);
413                         read_unlock(&ip6_frag_lock);
414                         return fq;
415                 }
416         }
417         read_unlock(&ip6_frag_lock);
418
419         return ip6_frag_create(id, src, dst, idev);
420 }
421
422
423 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
424                            struct frag_hdr *fhdr, int nhoff)
425 {
426         struct sk_buff *prev, *next;
427         int offset, end;
428
429         if (fq->last_in & COMPLETE)
430                 goto err;
431
432         offset = ntohs(fhdr->frag_off) & ~0x7;
433         end = offset + (ntohs(ipv6_hdr(skb)->payload_len) -
434                         ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
435
436         if ((unsigned int)end > IPV6_MAXPLEN) {
437                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
438                                  IPSTATS_MIB_INHDRERRORS);
439                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
440                                   ((u8 *)&fhdr->frag_off -
441                                    skb_network_header(skb)));
442                 return;
443         }
444
445         if (skb->ip_summed == CHECKSUM_COMPLETE) {
446                 const unsigned char *nh = skb_network_header(skb);
447                 skb->csum = csum_sub(skb->csum,
448                                      csum_partial(nh, (u8 *)(fhdr + 1) - nh,
449                                                   0));
450         }
451
452         /* Is this the final fragment? */
453         if (!(fhdr->frag_off & htons(IP6_MF))) {
454                 /* If we already have some bits beyond end
455                  * or have different end, the segment is corrupted.
456                  */
457                 if (end < fq->len ||
458                     ((fq->last_in & LAST_IN) && end != fq->len))
459                         goto err;
460                 fq->last_in |= LAST_IN;
461                 fq->len = end;
462         } else {
463                 /* Check if the fragment is rounded to 8 bytes.
464                  * Required by the RFC.
465                  */
466                 if (end & 0x7) {
467                         /* RFC2460 says always send parameter problem in
468                          * this case. -DaveM
469                          */
470                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
471                                          IPSTATS_MIB_INHDRERRORS);
472                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
473                                           offsetof(struct ipv6hdr, payload_len));
474                         return;
475                 }
476                 if (end > fq->len) {
477                         /* Some bits beyond end -> corruption. */
478                         if (fq->last_in & LAST_IN)
479                                 goto err;
480                         fq->len = end;
481                 }
482         }
483
484         if (end == offset)
485                 goto err;
486
487         /* Point into the IP datagram 'data' part. */
488         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
489                 goto err;
490
491         if (pskb_trim_rcsum(skb, end - offset))
492                 goto err;
493
494         /* Find out which fragments are in front and at the back of us
495          * in the chain of fragments so far.  We must know where to put
496          * this fragment, right?
497          */
498         prev = NULL;
499         for(next = fq->fragments; next != NULL; next = next->next) {
500                 if (FRAG6_CB(next)->offset >= offset)
501                         break;  /* bingo! */
502                 prev = next;
503         }
504
505         /* We found where to put this one.  Check for overlap with
506          * preceding fragment, and, if needed, align things so that
507          * any overlaps are eliminated.
508          */
509         if (prev) {
510                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
511
512                 if (i > 0) {
513                         offset += i;
514                         if (end <= offset)
515                                 goto err;
516                         if (!pskb_pull(skb, i))
517                                 goto err;
518                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
519                                 skb->ip_summed = CHECKSUM_NONE;
520                 }
521         }
522
523         /* Look for overlap with succeeding segments.
524          * If we can merge fragments, do it.
525          */
526         while (next && FRAG6_CB(next)->offset < end) {
527                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
528
529                 if (i < next->len) {
530                         /* Eat head of the next overlapped fragment
531                          * and leave the loop. The next ones cannot overlap.
532                          */
533                         if (!pskb_pull(next, i))
534                                 goto err;
535                         FRAG6_CB(next)->offset += i;    /* next fragment */
536                         fq->meat -= i;
537                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
538                                 next->ip_summed = CHECKSUM_NONE;
539                         break;
540                 } else {
541                         struct sk_buff *free_it = next;
542
543                         /* Old fragment is completely overridden with
544                          * new one drop it.
545                          */
546                         next = next->next;
547
548                         if (prev)
549                                 prev->next = next;
550                         else
551                                 fq->fragments = next;
552
553                         fq->meat -= free_it->len;
554                         frag_kfree_skb(free_it, NULL);
555                 }
556         }
557
558         FRAG6_CB(skb)->offset = offset;
559
560         /* Insert this fragment in the chain of fragments. */
561         skb->next = next;
562         if (prev)
563                 prev->next = skb;
564         else
565                 fq->fragments = skb;
566
567         if (skb->dev)
568                 fq->iif = skb->dev->ifindex;
569         skb->dev = NULL;
570         fq->stamp = skb->tstamp;
571         fq->meat += skb->len;
572         atomic_add(skb->truesize, &ip6_frag_mem);
573
574         /* The first fragment.
575          * nhoffset is obtained from the first fragment, of course.
576          */
577         if (offset == 0) {
578                 fq->nhoffset = nhoff;
579                 fq->last_in |= FIRST_IN;
580         }
581         write_lock(&ip6_frag_lock);
582         list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
583         write_unlock(&ip6_frag_lock);
584         return;
585
586 err:
587         IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
588         kfree_skb(skb);
589 }
590
591 /*
592  *      Check if this packet is complete.
593  *      Returns NULL on failure by any reason, and pointer
594  *      to current nexthdr field in reassembled frame.
595  *
596  *      It is called with locked fq, and caller must check that
597  *      queue is eligible for reassembly i.e. it is not COMPLETE,
598  *      the last and the first frames arrived and all the bits are here.
599  */
600 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
601                           struct net_device *dev)
602 {
603         struct sk_buff *fp, *head = fq->fragments;
604         int    payload_len;
605         unsigned int nhoff;
606
607         fq_kill(fq);
608
609         BUG_TRAP(head != NULL);
610         BUG_TRAP(FRAG6_CB(head)->offset == 0);
611
612         /* Unfragmented part is taken from the first segment. */
613         payload_len = ((head->data - skb_network_header(head)) -
614                        sizeof(struct ipv6hdr) + fq->len -
615                        sizeof(struct frag_hdr));
616         if (payload_len > IPV6_MAXPLEN)
617                 goto out_oversize;
618
619         /* Head of list must not be cloned. */
620         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
621                 goto out_oom;
622
623         /* If the first fragment is fragmented itself, we split
624          * it to two chunks: the first with data and paged part
625          * and the second, holding only fragments. */
626         if (skb_shinfo(head)->frag_list) {
627                 struct sk_buff *clone;
628                 int i, plen = 0;
629
630                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
631                         goto out_oom;
632                 clone->next = head->next;
633                 head->next = clone;
634                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
635                 skb_shinfo(head)->frag_list = NULL;
636                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
637                         plen += skb_shinfo(head)->frags[i].size;
638                 clone->len = clone->data_len = head->data_len - plen;
639                 head->data_len -= clone->len;
640                 head->len -= clone->len;
641                 clone->csum = 0;
642                 clone->ip_summed = head->ip_summed;
643                 atomic_add(clone->truesize, &ip6_frag_mem);
644         }
645
646         /* We have to remove fragment header from datagram and to relocate
647          * header in order to calculate ICV correctly. */
648         nhoff = fq->nhoffset;
649         skb_network_header(head)[nhoff] = head->h.raw[0];
650         memmove(head->head + sizeof(struct frag_hdr), head->head,
651                 (head->data - head->head) - sizeof(struct frag_hdr));
652         head->mac.raw += sizeof(struct frag_hdr);
653         head->nh.raw += sizeof(struct frag_hdr);
654
655         skb_shinfo(head)->frag_list = head->next;
656         head->h.raw = head->data;
657         skb_push(head, head->data - skb_network_header(head));
658         atomic_sub(head->truesize, &ip6_frag_mem);
659
660         for (fp=head->next; fp; fp = fp->next) {
661                 head->data_len += fp->len;
662                 head->len += fp->len;
663                 if (head->ip_summed != fp->ip_summed)
664                         head->ip_summed = CHECKSUM_NONE;
665                 else if (head->ip_summed == CHECKSUM_COMPLETE)
666                         head->csum = csum_add(head->csum, fp->csum);
667                 head->truesize += fp->truesize;
668                 atomic_sub(fp->truesize, &ip6_frag_mem);
669         }
670
671         head->next = NULL;
672         head->dev = dev;
673         head->tstamp = fq->stamp;
674         ipv6_hdr(head)->payload_len = htons(payload_len);
675         IP6CB(head)->nhoff = nhoff;
676
677         *skb_in = head;
678
679         /* Yes, and fold redundant checksum back. 8) */
680         if (head->ip_summed == CHECKSUM_COMPLETE)
681                 head->csum = csum_partial(skb_network_header(head),
682                                           head->h.raw - head->nh.raw,
683                                           head->csum);
684
685         rcu_read_lock();
686         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
687         rcu_read_unlock();
688         fq->fragments = NULL;
689         return 1;
690
691 out_oversize:
692         if (net_ratelimit())
693                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
694         goto out_fail;
695 out_oom:
696         if (net_ratelimit())
697                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
698 out_fail:
699         rcu_read_lock();
700         IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
701         rcu_read_unlock();
702         return -1;
703 }
704
705 static int ipv6_frag_rcv(struct sk_buff **skbp)
706 {
707         struct sk_buff *skb = *skbp;
708         struct net_device *dev = skb->dev;
709         struct frag_hdr *fhdr;
710         struct frag_queue *fq;
711         struct ipv6hdr *hdr = ipv6_hdr(skb);
712
713         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS);
714
715         /* Jumbo payload inhibits frag. header */
716         if (hdr->payload_len==0) {
717                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
718                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
719                 return -1;
720         }
721         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
722                 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
723                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
724                 return -1;
725         }
726
727         hdr = ipv6_hdr(skb);
728         fhdr = (struct frag_hdr *)skb->h.raw;
729
730         if (!(fhdr->frag_off & htons(0xFFF9))) {
731                 /* It is not a fragmented frame */
732                 skb->h.raw += sizeof(struct frag_hdr);
733                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS);
734
735                 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
736                 return 1;
737         }
738
739         if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
740                 ip6_evictor(ip6_dst_idev(skb->dst));
741
742         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr,
743                           ip6_dst_idev(skb->dst))) != NULL) {
744                 int ret = -1;
745
746                 spin_lock(&fq->lock);
747
748                 ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
749
750                 if (fq->last_in == (FIRST_IN|LAST_IN) &&
751                     fq->meat == fq->len)
752                         ret = ip6_frag_reasm(fq, skbp, dev);
753
754                 spin_unlock(&fq->lock);
755                 fq_put(fq, NULL);
756                 return ret;
757         }
758
759         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS);
760         kfree_skb(skb);
761         return -1;
762 }
763
764 static struct inet6_protocol frag_protocol =
765 {
766         .handler        =       ipv6_frag_rcv,
767         .flags          =       INET6_PROTO_NOPOLICY,
768 };
769
770 void __init ipv6_frag_init(void)
771 {
772         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
773                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
774
775         ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
776                                    (jiffies ^ (jiffies >> 6)));
777
778         init_timer(&ip6_frag_secret_timer);
779         ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
780         ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
781         add_timer(&ip6_frag_secret_timer);
782 }