Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | */ | |
1da177e4 LT |
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 | ||
ab32ea5d BH |
56 | int sysctl_ip6frag_high_thresh __read_mostly = 256*1024; |
57 | int sysctl_ip6frag_low_thresh __read_mostly = 192*1024; | |
1da177e4 | 58 | |
ab32ea5d | 59 | int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT; |
1da177e4 LT |
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 | { | |
e7c8a41e | 76 | struct hlist_node list; |
1da177e4 LT |
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; | |
1da177e4 LT |
97 | }; |
98 | ||
99 | /* Hash table. */ | |
100 | ||
101 | #define IP6Q_HASHSZ 64 | |
102 | ||
e7c8a41e | 103 | static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ]; |
1da177e4 LT |
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 | { | |
e7c8a41e | 111 | hlist_del(&fq->list); |
1da177e4 LT |
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 | ||
f6596f9d ZB |
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 | */ | |
1da177e4 LT |
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; | |
ab32ea5d | 155 | int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ; |
1da177e4 LT |
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; | |
e7c8a41e | 166 | struct hlist_node *p, *n; |
1da177e4 | 167 | |
e7c8a41e | 168 | hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) { |
1da177e4 LT |
169 | unsigned int hval = ip6qhashfn(q->id, |
170 | &q->saddr, | |
171 | &q->daddr); | |
172 | ||
173 | if (hval != i) { | |
e7c8a41e | 174 | hlist_del(&q->list); |
1da177e4 LT |
175 | |
176 | /* Relink to new hash chain. */ | |
e7c8a41e YK |
177 | hlist_add_head(&q->list, |
178 | &ip6_frag_hash[hval]); | |
1da177e4 | 179 | |
e7c8a41e | 180 | } |
1da177e4 LT |
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 | { | |
78c784c4 | 209 | struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); |
1da177e4 LT |
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; | |
78c784c4 | 294 | struct net_device *dev; |
1da177e4 LT |
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 | ||
78c784c4 IO |
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); | |
1da177e4 LT |
322 | out: |
323 | spin_unlock(&fq->lock); | |
324 | fq_put(fq, NULL); | |
325 | } | |
326 | ||
327 | /* Creation primitives. */ | |
328 | ||
329 | ||
f6596f9d | 330 | static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) |
1da177e4 LT |
331 | { |
332 | struct frag_queue *fq; | |
f6596f9d | 333 | unsigned int hash; |
e7c8a41e YK |
334 | #ifdef CONFIG_SMP |
335 | struct hlist_node *n; | |
336 | #endif | |
1da177e4 LT |
337 | |
338 | write_lock(&ip6_frag_lock); | |
f6596f9d | 339 | hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); |
1da177e4 | 340 | #ifdef CONFIG_SMP |
e7c8a41e | 341 | hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { |
1da177e4 LT |
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); | |
e7c8a41e | 359 | hlist_add_head(&fq->list, &ip6_frag_hash[hash]); |
1da177e4 LT |
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 * | |
f6596f9d | 369 | ip6_frag_create(u32 id, struct in6_addr *src, struct in6_addr *dst) |
1da177e4 LT |
370 | { |
371 | struct frag_queue *fq; | |
372 | ||
373 | if ((fq = frag_alloc_queue()) == NULL) | |
374 | goto oom; | |
375 | ||
1da177e4 LT |
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 | ||
f6596f9d | 386 | return ip6_frag_intern(fq); |
1da177e4 LT |
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; | |
e7c8a41e | 397 | struct hlist_node *n; |
f6596f9d | 398 | unsigned int hash; |
1da177e4 LT |
399 | |
400 | read_lock(&ip6_frag_lock); | |
f6596f9d | 401 | hash = ip6qhashfn(id, src, dst); |
e7c8a41e | 402 | hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { |
1da177e4 LT |
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 | ||
f6596f9d | 413 | return ip6_frag_create(id, src, dst); |
1da177e4 LT |
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 | ||
84fa7933 | 436 | if (skb->ip_summed == CHECKSUM_COMPLETE) |
1da177e4 LT |
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; | |
42ca89c1 SH |
477 | |
478 | if (pskb_trim_rcsum(skb, end - offset)) | |
479 | goto err; | |
1da177e4 LT |
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; | |
a61bbcf2 | 557 | skb_get_timestamp(skb, &fq->stamp); |
1da177e4 LT |
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, | |
1da177e4 LT |
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; | |
84fa7933 | 650 | else if (head->ip_summed == CHECKSUM_COMPLETE) |
1da177e4 LT |
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; | |
a61bbcf2 | 658 | skb_set_timestamp(head, &fq->stamp); |
1da177e4 | 659 | head->nh.ipv6h->payload_len = htons(payload_len); |
951dbc8a | 660 | IP6CB(head)->nhoff = nhoff; |
1da177e4 LT |
661 | |
662 | *skb_in = head; | |
663 | ||
664 | /* Yes, and fold redundant checksum back. 8) */ | |
84fa7933 | 665 | if (head->ip_summed == CHECKSUM_COMPLETE) |
1da177e4 LT |
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; | |
1da177e4 LT |
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 | ||
951dbc8a | 684 | static int ipv6_frag_rcv(struct sk_buff **skbp) |
1da177e4 LT |
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 | ||
951dbc8a | 716 | IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw; |
1da177e4 LT |
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 | ||
951dbc8a | 728 | ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); |
1da177e4 LT |
729 | |
730 | if (fq->last_in == (FIRST_IN|LAST_IN) && | |
731 | fq->meat == fq->len) | |
951dbc8a | 732 | ret = ip6_frag_reasm(fq, skbp, dev); |
1da177e4 LT |
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 | } |