Merge branch 'misc' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc...
[linux-2.6] / 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/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
57 int sysctl_ip6frag_high_thresh = 256*1024;
58 int sysctl_ip6frag_low_thresh = 192*1024;
59
60 int sysctl_ip6frag_time = 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         __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 };
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(u32 id, struct in6_addr *saddr,
129                                struct in6_addr *daddr)
130 {
131         u32 a, b, c;
132
133         a = saddr->s6_addr32[0];
134         b = saddr->s6_addr32[1];
135         c = 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 += saddr->s6_addr32[3];
143         b += daddr->s6_addr32[0];
144         c += daddr->s6_addr32[1];
145         __jhash_mix(a, b, c);
146
147         a += daddr->s6_addr32[2];
148         b += daddr->s6_addr32[3];
149         c += 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 = 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(void)
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(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;
296
297         spin_lock(&fq->lock);
298
299         if (fq->last_in & COMPLETE)
300                 goto out;
301
302         fq_kill(fq);
303
304         IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
305         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
306
307         /* Don't send error if the first segment did not arrive. */
308         if (!(fq->last_in&FIRST_IN) || !fq->fragments)
309                 goto out;
310
311         dev = dev_get_by_index(fq->iif);
312         if (!dev)
313                 goto out;
314
315         /*
316            But use as source device on which LAST ARRIVED
317            segment was received. And do not use fq->dev
318            pointer directly, device might already disappeared.
319          */
320         fq->fragments->dev = dev;
321         icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
322         dev_put(dev);
323 out:
324         spin_unlock(&fq->lock);
325         fq_put(fq, NULL);
326 }
327
328 /* Creation primitives. */
329
330
331 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in)
332 {
333         struct frag_queue *fq;
334         unsigned int hash;
335 #ifdef CONFIG_SMP
336         struct hlist_node *n;
337 #endif
338
339         write_lock(&ip6_frag_lock);
340         hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr);
341 #ifdef CONFIG_SMP
342         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
343                 if (fq->id == fq_in->id && 
344                     ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
345                     ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
346                         atomic_inc(&fq->refcnt);
347                         write_unlock(&ip6_frag_lock);
348                         fq_in->last_in |= COMPLETE;
349                         fq_put(fq_in, NULL);
350                         return fq;
351                 }
352         }
353 #endif
354         fq = fq_in;
355
356         if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
357                 atomic_inc(&fq->refcnt);
358
359         atomic_inc(&fq->refcnt);
360         hlist_add_head(&fq->list, &ip6_frag_hash[hash]);
361         INIT_LIST_HEAD(&fq->lru_list);
362         list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
363         ip6_frag_nqueues++;
364         write_unlock(&ip6_frag_lock);
365         return fq;
366 }
367
368
369 static struct frag_queue *
370 ip6_frag_create(u32 id, struct in6_addr *src, struct in6_addr *dst)
371 {
372         struct frag_queue *fq;
373
374         if ((fq = frag_alloc_queue()) == NULL)
375                 goto oom;
376
377         fq->id = id;
378         ipv6_addr_copy(&fq->saddr, src);
379         ipv6_addr_copy(&fq->daddr, dst);
380
381         init_timer(&fq->timer);
382         fq->timer.function = ip6_frag_expire;
383         fq->timer.data = (long) fq;
384         spin_lock_init(&fq->lock);
385         atomic_set(&fq->refcnt, 1);
386
387         return ip6_frag_intern(fq);
388
389 oom:
390         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
391         return NULL;
392 }
393
394 static __inline__ struct frag_queue *
395 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
396 {
397         struct frag_queue *fq;
398         struct hlist_node *n;
399         unsigned int hash;
400
401         read_lock(&ip6_frag_lock);
402         hash = ip6qhashfn(id, src, dst);
403         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
404                 if (fq->id == id && 
405                     ipv6_addr_equal(src, &fq->saddr) &&
406                     ipv6_addr_equal(dst, &fq->daddr)) {
407                         atomic_inc(&fq->refcnt);
408                         read_unlock(&ip6_frag_lock);
409                         return fq;
410                 }
411         }
412         read_unlock(&ip6_frag_lock);
413
414         return ip6_frag_create(id, src, dst);
415 }
416
417
418 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 
419                            struct frag_hdr *fhdr, int nhoff)
420 {
421         struct sk_buff *prev, *next;
422         int offset, end;
423
424         if (fq->last_in & COMPLETE)
425                 goto err;
426
427         offset = ntohs(fhdr->frag_off) & ~0x7;
428         end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
429                         ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
430
431         if ((unsigned int)end > IPV6_MAXPLEN) {
432                 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
433                 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
434                 return;
435         }
436
437         if (skb->ip_summed == CHECKSUM_HW)
438                 skb->csum = csum_sub(skb->csum,
439                                      csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
440
441         /* Is this the final fragment? */
442         if (!(fhdr->frag_off & htons(IP6_MF))) {
443                 /* If we already have some bits beyond end
444                  * or have different end, the segment is corrupted.
445                  */
446                 if (end < fq->len ||
447                     ((fq->last_in & LAST_IN) && end != fq->len))
448                         goto err;
449                 fq->last_in |= LAST_IN;
450                 fq->len = end;
451         } else {
452                 /* Check if the fragment is rounded to 8 bytes.
453                  * Required by the RFC.
454                  */
455                 if (end & 0x7) {
456                         /* RFC2460 says always send parameter problem in
457                          * this case. -DaveM
458                          */
459                         IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
460                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 
461                                           offsetof(struct ipv6hdr, payload_len));
462                         return;
463                 }
464                 if (end > fq->len) {
465                         /* Some bits beyond end -> corruption. */
466                         if (fq->last_in & LAST_IN)
467                                 goto err;
468                         fq->len = end;
469                 }
470         }
471
472         if (end == offset)
473                 goto err;
474
475         /* Point into the IP datagram 'data' part. */
476         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
477                 goto err;
478         
479         if (pskb_trim_rcsum(skb, end - offset))
480                 goto err;
481
482         /* Find out which fragments are in front and at the back of us
483          * in the chain of fragments so far.  We must know where to put
484          * this fragment, right?
485          */
486         prev = NULL;
487         for(next = fq->fragments; next != NULL; next = next->next) {
488                 if (FRAG6_CB(next)->offset >= offset)
489                         break;  /* bingo! */
490                 prev = next;
491         }
492
493         /* We found where to put this one.  Check for overlap with
494          * preceding fragment, and, if needed, align things so that
495          * any overlaps are eliminated.
496          */
497         if (prev) {
498                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
499
500                 if (i > 0) {
501                         offset += i;
502                         if (end <= offset)
503                                 goto err;
504                         if (!pskb_pull(skb, i))
505                                 goto err;
506                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
507                                 skb->ip_summed = CHECKSUM_NONE;
508                 }
509         }
510
511         /* Look for overlap with succeeding segments.
512          * If we can merge fragments, do it.
513          */
514         while (next && FRAG6_CB(next)->offset < end) {
515                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
516
517                 if (i < next->len) {
518                         /* Eat head of the next overlapped fragment
519                          * and leave the loop. The next ones cannot overlap.
520                          */
521                         if (!pskb_pull(next, i))
522                                 goto err;
523                         FRAG6_CB(next)->offset += i;    /* next fragment */
524                         fq->meat -= i;
525                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
526                                 next->ip_summed = CHECKSUM_NONE;
527                         break;
528                 } else {
529                         struct sk_buff *free_it = next;
530
531                         /* Old fragment is completely overridden with
532                          * new one drop it.
533                          */
534                         next = next->next;
535
536                         if (prev)
537                                 prev->next = next;
538                         else
539                                 fq->fragments = next;
540
541                         fq->meat -= free_it->len;
542                         frag_kfree_skb(free_it, NULL);
543                 }
544         }
545
546         FRAG6_CB(skb)->offset = offset;
547
548         /* Insert this fragment in the chain of fragments. */
549         skb->next = next;
550         if (prev)
551                 prev->next = skb;
552         else
553                 fq->fragments = skb;
554
555         if (skb->dev)
556                 fq->iif = skb->dev->ifindex;
557         skb->dev = NULL;
558         skb_get_timestamp(skb, &fq->stamp);
559         fq->meat += skb->len;
560         atomic_add(skb->truesize, &ip6_frag_mem);
561
562         /* The first fragment.
563          * nhoffset is obtained from the first fragment, of course.
564          */
565         if (offset == 0) {
566                 fq->nhoffset = nhoff;
567                 fq->last_in |= FIRST_IN;
568         }
569         write_lock(&ip6_frag_lock);
570         list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
571         write_unlock(&ip6_frag_lock);
572         return;
573
574 err:
575         IP6_INC_STATS(IPSTATS_MIB_REASMFAILS);
576         kfree_skb(skb);
577 }
578
579 /*
580  *      Check if this packet is complete.
581  *      Returns NULL on failure by any reason, and pointer
582  *      to current nexthdr field in reassembled frame.
583  *
584  *      It is called with locked fq, and caller must check that
585  *      queue is eligible for reassembly i.e. it is not COMPLETE,
586  *      the last and the first frames arrived and all the bits are here.
587  */
588 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
589                           struct net_device *dev)
590 {
591         struct sk_buff *fp, *head = fq->fragments;
592         int    payload_len;
593         unsigned int nhoff;
594
595         fq_kill(fq);
596
597         BUG_TRAP(head != NULL);
598         BUG_TRAP(FRAG6_CB(head)->offset == 0);
599
600         /* Unfragmented part is taken from the first segment. */
601         payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
602         if (payload_len > IPV6_MAXPLEN)
603                 goto out_oversize;
604
605         /* Head of list must not be cloned. */
606         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
607                 goto out_oom;
608
609         /* If the first fragment is fragmented itself, we split
610          * it to two chunks: the first with data and paged part
611          * and the second, holding only fragments. */
612         if (skb_shinfo(head)->frag_list) {
613                 struct sk_buff *clone;
614                 int i, plen = 0;
615
616                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
617                         goto out_oom;
618                 clone->next = head->next;
619                 head->next = clone;
620                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
621                 skb_shinfo(head)->frag_list = NULL;
622                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
623                         plen += skb_shinfo(head)->frags[i].size;
624                 clone->len = clone->data_len = head->data_len - plen;
625                 head->data_len -= clone->len;
626                 head->len -= clone->len;
627                 clone->csum = 0;
628                 clone->ip_summed = head->ip_summed;
629                 atomic_add(clone->truesize, &ip6_frag_mem);
630         }
631
632         /* We have to remove fragment header from datagram and to relocate
633          * header in order to calculate ICV correctly. */
634         nhoff = fq->nhoffset;
635         head->nh.raw[nhoff] = head->h.raw[0];
636         memmove(head->head + sizeof(struct frag_hdr), head->head, 
637                 (head->data - head->head) - sizeof(struct frag_hdr));
638         head->mac.raw += sizeof(struct frag_hdr);
639         head->nh.raw += sizeof(struct frag_hdr);
640
641         skb_shinfo(head)->frag_list = head->next;
642         head->h.raw = head->data;
643         skb_push(head, head->data - head->nh.raw);
644         atomic_sub(head->truesize, &ip6_frag_mem);
645
646         for (fp=head->next; fp; fp = fp->next) {
647                 head->data_len += fp->len;
648                 head->len += fp->len;
649                 if (head->ip_summed != fp->ip_summed)
650                         head->ip_summed = CHECKSUM_NONE;
651                 else if (head->ip_summed == CHECKSUM_HW)
652                         head->csum = csum_add(head->csum, fp->csum);
653                 head->truesize += fp->truesize;
654                 atomic_sub(fp->truesize, &ip6_frag_mem);
655         }
656
657         head->next = NULL;
658         head->dev = dev;
659         skb_set_timestamp(head, &fq->stamp);
660         head->nh.ipv6h->payload_len = htons(payload_len);
661         IP6CB(head)->nhoff = nhoff;
662
663         *skb_in = head;
664
665         /* Yes, and fold redundant checksum back. 8) */
666         if (head->ip_summed == CHECKSUM_HW)
667                 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
668
669         IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
670         fq->fragments = NULL;
671         return 1;
672
673 out_oversize:
674         if (net_ratelimit())
675                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
676         goto out_fail;
677 out_oom:
678         if (net_ratelimit())
679                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
680 out_fail:
681         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
682         return -1;
683 }
684
685 static int ipv6_frag_rcv(struct sk_buff **skbp)
686 {
687         struct sk_buff *skb = *skbp; 
688         struct net_device *dev = skb->dev;
689         struct frag_hdr *fhdr;
690         struct frag_queue *fq;
691         struct ipv6hdr *hdr;
692
693         hdr = skb->nh.ipv6h;
694
695         IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
696
697         /* Jumbo payload inhibits frag. header */
698         if (hdr->payload_len==0) {
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         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
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
709         hdr = skb->nh.ipv6h;
710         fhdr = (struct frag_hdr *)skb->h.raw;
711
712         if (!(fhdr->frag_off & htons(0xFFF9))) {
713                 /* It is not a fragmented frame */
714                 skb->h.raw += sizeof(struct frag_hdr);
715                 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
716
717                 IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw;
718                 return 1;
719         }
720
721         if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
722                 ip6_evictor();
723
724         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
725                 int ret = -1;
726
727                 spin_lock(&fq->lock);
728
729                 ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
730
731                 if (fq->last_in == (FIRST_IN|LAST_IN) &&
732                     fq->meat == fq->len)
733                         ret = ip6_frag_reasm(fq, skbp, dev);
734
735                 spin_unlock(&fq->lock);
736                 fq_put(fq, NULL);
737                 return ret;
738         }
739
740         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
741         kfree_skb(skb);
742         return -1;
743 }
744
745 static struct inet6_protocol frag_protocol =
746 {
747         .handler        =       ipv6_frag_rcv,
748         .flags          =       INET6_PROTO_NOPOLICY,
749 };
750
751 void __init ipv6_frag_init(void)
752 {
753         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
754                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
755
756         ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
757                                    (jiffies ^ (jiffies >> 6)));
758
759         init_timer(&ip6_frag_secret_timer);
760         ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
761         ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
762         add_timer(&ip6_frag_secret_timer);
763 }