[NET]: is it Andy or Andi ??
[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/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/protocol.h>
51 #include <net/transp_v6.h>
52 #include <net/rawv6.h>
53 #include <net/ndisc.h>
54 #include <net/addrconf.h>
55
56 int sysctl_ip6frag_high_thresh __read_mostly = 256*1024;
57 int sysctl_ip6frag_low_thresh __read_mostly = 192*1024;
58
59 int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT;
60
61 struct ip6frag_skb_cb
62 {
63         struct inet6_skb_parm   h;
64         int                     offset;
65 };
66
67 #define FRAG6_CB(skb)   ((struct ip6frag_skb_cb*)((skb)->cb))
68
69
70 /*
71  *      Equivalent of ipv4 struct ipq
72  */
73
74 struct frag_queue
75 {
76         struct hlist_node       list;
77         struct list_head lru_list;              /* lru list member      */
78
79         __u32                   id;             /* fragment id          */
80         struct in6_addr         saddr;
81         struct in6_addr         daddr;
82
83         spinlock_t              lock;
84         atomic_t                refcnt;
85         struct timer_list       timer;          /* expire timer         */
86         struct sk_buff          *fragments;
87         int                     len;
88         int                     meat;
89         int                     iif;
90         struct timeval          stamp;
91         unsigned int            csum;
92         __u8                    last_in;        /* has first/last segment arrived? */
93 #define COMPLETE                4
94 #define FIRST_IN                2
95 #define LAST_IN                 1
96         __u16                   nhoffset;
97 };
98
99 /* Hash table. */
100
101 #define IP6Q_HASHSZ     64
102
103 static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ];
104 static DEFINE_RWLOCK(ip6_frag_lock);
105 static u32 ip6_frag_hash_rnd;
106 static LIST_HEAD(ip6_frag_lru_list);
107 int ip6_frag_nqueues = 0;
108
109 static __inline__ void __fq_unlink(struct frag_queue *fq)
110 {
111         hlist_del(&fq->list);
112         list_del(&fq->lru_list);
113         ip6_frag_nqueues--;
114 }
115
116 static __inline__ void fq_unlink(struct frag_queue *fq)
117 {
118         write_lock(&ip6_frag_lock);
119         __fq_unlink(fq);
120         write_unlock(&ip6_frag_lock);
121 }
122
123 /*
124  * callers should be careful not to use the hash value outside the ipfrag_lock
125  * as doing so could race with ipfrag_hash_rnd being recalculated.
126  */
127 static 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
154 static struct timer_list ip6_frag_secret_timer;
155 int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ;
156
157 static 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                 struct hlist_node *p, *n;
167
168                 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) {
169                         unsigned int hval = ip6qhashfn(q->id,
170                                                        &q->saddr,
171                                                        &q->daddr);
172
173                         if (hval != i) {
174                                 hlist_del(&q->list);
175
176                                 /* Relink to new hash chain. */
177                                 hlist_add_head(&q->list,
178                                                &ip6_frag_hash[hval]);
179
180                         }
181                 }
182         }
183         write_unlock(&ip6_frag_lock);
184
185         mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval);
186 }
187
188 atomic_t ip6_frag_mem = ATOMIC_INIT(0);
189
190 /* Memory Tracking Functions. */
191 static inline void frag_kfree_skb(struct sk_buff *skb, int *work)
192 {
193         if (work)
194                 *work -= skb->truesize;
195         atomic_sub(skb->truesize, &ip6_frag_mem);
196         kfree_skb(skb);
197 }
198
199 static inline void frag_free_queue(struct frag_queue *fq, int *work)
200 {
201         if (work)
202                 *work -= sizeof(struct frag_queue);
203         atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem);
204         kfree(fq);
205 }
206
207 static inline struct frag_queue *frag_alloc_queue(void)
208 {
209         struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC);
210
211         if(!fq)
212                 return NULL;
213         atomic_add(sizeof(struct frag_queue), &ip6_frag_mem);
214         return fq;
215 }
216
217 /* Destruction primitives. */
218
219 /* Complete destruction of fq. */
220 static void ip6_frag_destroy(struct frag_queue *fq, int *work)
221 {
222         struct sk_buff *fp;
223
224         BUG_TRAP(fq->last_in&COMPLETE);
225         BUG_TRAP(del_timer(&fq->timer) == 0);
226
227         /* Release all fragment data. */
228         fp = fq->fragments;
229         while (fp) {
230                 struct sk_buff *xp = fp->next;
231
232                 frag_kfree_skb(fp, work);
233                 fp = xp;
234         }
235
236         frag_free_queue(fq, work);
237 }
238
239 static __inline__ void fq_put(struct frag_queue *fq, int *work)
240 {
241         if (atomic_dec_and_test(&fq->refcnt))
242                 ip6_frag_destroy(fq, work);
243 }
244
245 /* Kill fq entry. It is not destroyed immediately,
246  * because caller (and someone more) holds reference count.
247  */
248 static __inline__ void fq_kill(struct frag_queue *fq)
249 {
250         if (del_timer(&fq->timer))
251                 atomic_dec(&fq->refcnt);
252
253         if (!(fq->last_in & COMPLETE)) {
254                 fq_unlink(fq);
255                 atomic_dec(&fq->refcnt);
256                 fq->last_in |= COMPLETE;
257         }
258 }
259
260 static void ip6_evictor(void)
261 {
262         struct frag_queue *fq;
263         struct list_head *tmp;
264         int work;
265
266         work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh;
267         if (work <= 0)
268                 return;
269
270         while(work > 0) {
271                 read_lock(&ip6_frag_lock);
272                 if (list_empty(&ip6_frag_lru_list)) {
273                         read_unlock(&ip6_frag_lock);
274                         return;
275                 }
276                 tmp = ip6_frag_lru_list.next;
277                 fq = list_entry(tmp, struct frag_queue, lru_list);
278                 atomic_inc(&fq->refcnt);
279                 read_unlock(&ip6_frag_lock);
280
281                 spin_lock(&fq->lock);
282                 if (!(fq->last_in&COMPLETE))
283                         fq_kill(fq);
284                 spin_unlock(&fq->lock);
285
286                 fq_put(fq, &work);
287                 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
288         }
289 }
290
291 static void ip6_frag_expire(unsigned long data)
292 {
293         struct frag_queue *fq = (struct frag_queue *) data;
294         struct net_device *dev;
295
296         spin_lock(&fq->lock);
297
298         if (fq->last_in & COMPLETE)
299                 goto out;
300
301         fq_kill(fq);
302
303         IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT);
304         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
305
306         /* Don't send error if the first segment did not arrive. */
307         if (!(fq->last_in&FIRST_IN) || !fq->fragments)
308                 goto out;
309
310         dev = dev_get_by_index(fq->iif);
311         if (!dev)
312                 goto out;
313
314         /*
315            But use as source device on which LAST ARRIVED
316            segment was received. And do not use fq->dev
317            pointer directly, device might already disappeared.
318          */
319         fq->fragments->dev = dev;
320         icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);
321         dev_put(dev);
322 out:
323         spin_unlock(&fq->lock);
324         fq_put(fq, NULL);
325 }
326
327 /* Creation primitives. */
328
329
330 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in)
331 {
332         struct frag_queue *fq;
333         unsigned int hash;
334 #ifdef CONFIG_SMP
335         struct hlist_node *n;
336 #endif
337
338         write_lock(&ip6_frag_lock);
339         hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr);
340 #ifdef CONFIG_SMP
341         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
342                 if (fq->id == fq_in->id && 
343                     ipv6_addr_equal(&fq_in->saddr, &fq->saddr) &&
344                     ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) {
345                         atomic_inc(&fq->refcnt);
346                         write_unlock(&ip6_frag_lock);
347                         fq_in->last_in |= COMPLETE;
348                         fq_put(fq_in, NULL);
349                         return fq;
350                 }
351         }
352 #endif
353         fq = fq_in;
354
355         if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time))
356                 atomic_inc(&fq->refcnt);
357
358         atomic_inc(&fq->refcnt);
359         hlist_add_head(&fq->list, &ip6_frag_hash[hash]);
360         INIT_LIST_HEAD(&fq->lru_list);
361         list_add_tail(&fq->lru_list, &ip6_frag_lru_list);
362         ip6_frag_nqueues++;
363         write_unlock(&ip6_frag_lock);
364         return fq;
365 }
366
367
368 static struct frag_queue *
369 ip6_frag_create(u32 id, struct in6_addr *src, struct in6_addr *dst)
370 {
371         struct frag_queue *fq;
372
373         if ((fq = frag_alloc_queue()) == NULL)
374                 goto oom;
375
376         fq->id = id;
377         ipv6_addr_copy(&fq->saddr, src);
378         ipv6_addr_copy(&fq->daddr, dst);
379
380         init_timer(&fq->timer);
381         fq->timer.function = ip6_frag_expire;
382         fq->timer.data = (long) fq;
383         spin_lock_init(&fq->lock);
384         atomic_set(&fq->refcnt, 1);
385
386         return ip6_frag_intern(fq);
387
388 oom:
389         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
390         return NULL;
391 }
392
393 static __inline__ struct frag_queue *
394 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst)
395 {
396         struct frag_queue *fq;
397         struct hlist_node *n;
398         unsigned int hash;
399
400         read_lock(&ip6_frag_lock);
401         hash = ip6qhashfn(id, src, dst);
402         hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) {
403                 if (fq->id == id && 
404                     ipv6_addr_equal(src, &fq->saddr) &&
405                     ipv6_addr_equal(dst, &fq->daddr)) {
406                         atomic_inc(&fq->refcnt);
407                         read_unlock(&ip6_frag_lock);
408                         return fq;
409                 }
410         }
411         read_unlock(&ip6_frag_lock);
412
413         return ip6_frag_create(id, src, dst);
414 }
415
416
417 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 
418                            struct frag_hdr *fhdr, int nhoff)
419 {
420         struct sk_buff *prev, *next;
421         int offset, end;
422
423         if (fq->last_in & COMPLETE)
424                 goto err;
425
426         offset = ntohs(fhdr->frag_off) & ~0x7;
427         end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
428                         ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
429
430         if ((unsigned int)end > IPV6_MAXPLEN) {
431                 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
432                 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
433                 return;
434         }
435
436         if (skb->ip_summed == CHECKSUM_COMPLETE)
437                 skb->csum = csum_sub(skb->csum,
438                                      csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0));
439
440         /* Is this the final fragment? */
441         if (!(fhdr->frag_off & htons(IP6_MF))) {
442                 /* If we already have some bits beyond end
443                  * or have different end, the segment is corrupted.
444                  */
445                 if (end < fq->len ||
446                     ((fq->last_in & LAST_IN) && end != fq->len))
447                         goto err;
448                 fq->last_in |= LAST_IN;
449                 fq->len = end;
450         } else {
451                 /* Check if the fragment is rounded to 8 bytes.
452                  * Required by the RFC.
453                  */
454                 if (end & 0x7) {
455                         /* RFC2460 says always send parameter problem in
456                          * this case. -DaveM
457                          */
458                         IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
459                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 
460                                           offsetof(struct ipv6hdr, payload_len));
461                         return;
462                 }
463                 if (end > fq->len) {
464                         /* Some bits beyond end -> corruption. */
465                         if (fq->last_in & LAST_IN)
466                                 goto err;
467                         fq->len = end;
468                 }
469         }
470
471         if (end == offset)
472                 goto err;
473
474         /* Point into the IP datagram 'data' part. */
475         if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data))
476                 goto err;
477         
478         if (pskb_trim_rcsum(skb, end - offset))
479                 goto err;
480
481         /* Find out which fragments are in front and at the back of us
482          * in the chain of fragments so far.  We must know where to put
483          * this fragment, right?
484          */
485         prev = NULL;
486         for(next = fq->fragments; next != NULL; next = next->next) {
487                 if (FRAG6_CB(next)->offset >= offset)
488                         break;  /* bingo! */
489                 prev = next;
490         }
491
492         /* We found where to put this one.  Check for overlap with
493          * preceding fragment, and, if needed, align things so that
494          * any overlaps are eliminated.
495          */
496         if (prev) {
497                 int i = (FRAG6_CB(prev)->offset + prev->len) - offset;
498
499                 if (i > 0) {
500                         offset += i;
501                         if (end <= offset)
502                                 goto err;
503                         if (!pskb_pull(skb, i))
504                                 goto err;
505                         if (skb->ip_summed != CHECKSUM_UNNECESSARY)
506                                 skb->ip_summed = CHECKSUM_NONE;
507                 }
508         }
509
510         /* Look for overlap with succeeding segments.
511          * If we can merge fragments, do it.
512          */
513         while (next && FRAG6_CB(next)->offset < end) {
514                 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */
515
516                 if (i < next->len) {
517                         /* Eat head of the next overlapped fragment
518                          * and leave the loop. The next ones cannot overlap.
519                          */
520                         if (!pskb_pull(next, i))
521                                 goto err;
522                         FRAG6_CB(next)->offset += i;    /* next fragment */
523                         fq->meat -= i;
524                         if (next->ip_summed != CHECKSUM_UNNECESSARY)
525                                 next->ip_summed = CHECKSUM_NONE;
526                         break;
527                 } else {
528                         struct sk_buff *free_it = next;
529
530                         /* Old fragment is completely overridden with
531                          * new one drop it.
532                          */
533                         next = next->next;
534
535                         if (prev)
536                                 prev->next = next;
537                         else
538                                 fq->fragments = next;
539
540                         fq->meat -= free_it->len;
541                         frag_kfree_skb(free_it, NULL);
542                 }
543         }
544
545         FRAG6_CB(skb)->offset = offset;
546
547         /* Insert this fragment in the chain of fragments. */
548         skb->next = next;
549         if (prev)
550                 prev->next = skb;
551         else
552                 fq->fragments = skb;
553
554         if (skb->dev)
555                 fq->iif = skb->dev->ifindex;
556         skb->dev = NULL;
557         skb_get_timestamp(skb, &fq->stamp);
558         fq->meat += skb->len;
559         atomic_add(skb->truesize, &ip6_frag_mem);
560
561         /* The first fragment.
562          * nhoffset is obtained from the first fragment, of course.
563          */
564         if (offset == 0) {
565                 fq->nhoffset = nhoff;
566                 fq->last_in |= FIRST_IN;
567         }
568         write_lock(&ip6_frag_lock);
569         list_move_tail(&fq->lru_list, &ip6_frag_lru_list);
570         write_unlock(&ip6_frag_lock);
571         return;
572
573 err:
574         IP6_INC_STATS(IPSTATS_MIB_REASMFAILS);
575         kfree_skb(skb);
576 }
577
578 /*
579  *      Check if this packet is complete.
580  *      Returns NULL on failure by any reason, and pointer
581  *      to current nexthdr field in reassembled frame.
582  *
583  *      It is called with locked fq, and caller must check that
584  *      queue is eligible for reassembly i.e. it is not COMPLETE,
585  *      the last and the first frames arrived and all the bits are here.
586  */
587 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
588                           struct net_device *dev)
589 {
590         struct sk_buff *fp, *head = fq->fragments;
591         int    payload_len;
592         unsigned int nhoff;
593
594         fq_kill(fq);
595
596         BUG_TRAP(head != NULL);
597         BUG_TRAP(FRAG6_CB(head)->offset == 0);
598
599         /* Unfragmented part is taken from the first segment. */
600         payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
601         if (payload_len > IPV6_MAXPLEN)
602                 goto out_oversize;
603
604         /* Head of list must not be cloned. */
605         if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
606                 goto out_oom;
607
608         /* If the first fragment is fragmented itself, we split
609          * it to two chunks: the first with data and paged part
610          * and the second, holding only fragments. */
611         if (skb_shinfo(head)->frag_list) {
612                 struct sk_buff *clone;
613                 int i, plen = 0;
614
615                 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
616                         goto out_oom;
617                 clone->next = head->next;
618                 head->next = clone;
619                 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
620                 skb_shinfo(head)->frag_list = NULL;
621                 for (i=0; i<skb_shinfo(head)->nr_frags; i++)
622                         plen += skb_shinfo(head)->frags[i].size;
623                 clone->len = clone->data_len = head->data_len - plen;
624                 head->data_len -= clone->len;
625                 head->len -= clone->len;
626                 clone->csum = 0;
627                 clone->ip_summed = head->ip_summed;
628                 atomic_add(clone->truesize, &ip6_frag_mem);
629         }
630
631         /* We have to remove fragment header from datagram and to relocate
632          * header in order to calculate ICV correctly. */
633         nhoff = fq->nhoffset;
634         head->nh.raw[nhoff] = head->h.raw[0];
635         memmove(head->head + sizeof(struct frag_hdr), head->head, 
636                 (head->data - head->head) - sizeof(struct frag_hdr));
637         head->mac.raw += sizeof(struct frag_hdr);
638         head->nh.raw += sizeof(struct frag_hdr);
639
640         skb_shinfo(head)->frag_list = head->next;
641         head->h.raw = head->data;
642         skb_push(head, head->data - head->nh.raw);
643         atomic_sub(head->truesize, &ip6_frag_mem);
644
645         for (fp=head->next; fp; fp = fp->next) {
646                 head->data_len += fp->len;
647                 head->len += fp->len;
648                 if (head->ip_summed != fp->ip_summed)
649                         head->ip_summed = CHECKSUM_NONE;
650                 else if (head->ip_summed == CHECKSUM_COMPLETE)
651                         head->csum = csum_add(head->csum, fp->csum);
652                 head->truesize += fp->truesize;
653                 atomic_sub(fp->truesize, &ip6_frag_mem);
654         }
655
656         head->next = NULL;
657         head->dev = dev;
658         skb_set_timestamp(head, &fq->stamp);
659         head->nh.ipv6h->payload_len = htons(payload_len);
660         IP6CB(head)->nhoff = nhoff;
661
662         *skb_in = head;
663
664         /* Yes, and fold redundant checksum back. 8) */
665         if (head->ip_summed == CHECKSUM_COMPLETE)
666                 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum);
667
668         IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
669         fq->fragments = NULL;
670         return 1;
671
672 out_oversize:
673         if (net_ratelimit())
674                 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len);
675         goto out_fail;
676 out_oom:
677         if (net_ratelimit())
678                 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n");
679 out_fail:
680         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
681         return -1;
682 }
683
684 static int ipv6_frag_rcv(struct sk_buff **skbp)
685 {
686         struct sk_buff *skb = *skbp; 
687         struct net_device *dev = skb->dev;
688         struct frag_hdr *fhdr;
689         struct frag_queue *fq;
690         struct ipv6hdr *hdr;
691
692         hdr = skb->nh.ipv6h;
693
694         IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS);
695
696         /* Jumbo payload inhibits frag. header */
697         if (hdr->payload_len==0) {
698                 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
699                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
700                 return -1;
701         }
702         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) {
703                 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS);
704                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
705                 return -1;
706         }
707
708         hdr = skb->nh.ipv6h;
709         fhdr = (struct frag_hdr *)skb->h.raw;
710
711         if (!(fhdr->frag_off & htons(0xFFF9))) {
712                 /* It is not a fragmented frame */
713                 skb->h.raw += sizeof(struct frag_hdr);
714                 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS);
715
716                 IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw;
717                 return 1;
718         }
719
720         if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh)
721                 ip6_evictor();
722
723         if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) {
724                 int ret = -1;
725
726                 spin_lock(&fq->lock);
727
728                 ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff);
729
730                 if (fq->last_in == (FIRST_IN|LAST_IN) &&
731                     fq->meat == fq->len)
732                         ret = ip6_frag_reasm(fq, skbp, dev);
733
734                 spin_unlock(&fq->lock);
735                 fq_put(fq, NULL);
736                 return ret;
737         }
738
739         IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS);
740         kfree_skb(skb);
741         return -1;
742 }
743
744 static struct inet6_protocol frag_protocol =
745 {
746         .handler        =       ipv6_frag_rcv,
747         .flags          =       INET6_PROTO_NOPOLICY,
748 };
749
750 void __init ipv6_frag_init(void)
751 {
752         if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0)
753                 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n");
754
755         ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
756                                    (jiffies ^ (jiffies >> 6)));
757
758         init_timer(&ip6_frag_secret_timer);
759         ip6_frag_secret_timer.function = ip6_frag_secret_rebuild;
760         ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval;
761         add_timer(&ip6_frag_secret_timer);
762 }