Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
3 | * operating system. INET is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * The IP fragmentation functionality. | |
7 | * | |
8 | * Version: $Id: ip_fragment.c,v 1.59 2002/01/12 07:54:56 davem Exp $ | |
9 | * | |
10 | * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> | |
11 | * Alan Cox <Alan.Cox@linux.org> | |
12 | * | |
13 | * Fixes: | |
14 | * Alan Cox : Split from ip.c , see ip_input.c for history. | |
15 | * David S. Miller : Begin massive cleanup... | |
16 | * Andi Kleen : Add sysctls. | |
17 | * xxxx : Overlapfrag bug. | |
18 | * Ultima : ip_expire() kernel panic. | |
19 | * Bill Hawes : Frag accounting and evictor fixes. | |
20 | * John McDonald : 0 length frag bug. | |
21 | * Alexey Kuznetsov: SMP races, threading, cleanup. | |
22 | * Patrick McHardy : LRU queue of frag heads for evictor. | |
23 | */ | |
24 | ||
25 | #include <linux/config.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/types.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/jiffies.h> | |
30 | #include <linux/skbuff.h> | |
31 | #include <linux/list.h> | |
32 | #include <linux/ip.h> | |
33 | #include <linux/icmp.h> | |
34 | #include <linux/netdevice.h> | |
35 | #include <linux/jhash.h> | |
36 | #include <linux/random.h> | |
37 | #include <net/sock.h> | |
38 | #include <net/ip.h> | |
39 | #include <net/icmp.h> | |
40 | #include <net/checksum.h> | |
41 | #include <linux/tcp.h> | |
42 | #include <linux/udp.h> | |
43 | #include <linux/inet.h> | |
44 | #include <linux/netfilter_ipv4.h> | |
45 | ||
46 | /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 | |
47 | * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c | |
48 | * as well. Or notify me, at least. --ANK | |
49 | */ | |
50 | ||
51 | /* Fragment cache limits. We will commit 256K at one time. Should we | |
52 | * cross that limit we will prune down to 192K. This should cope with | |
53 | * even the most extreme cases without allowing an attacker to measurably | |
54 | * harm machine performance. | |
55 | */ | |
56 | int sysctl_ipfrag_high_thresh = 256*1024; | |
57 | int sysctl_ipfrag_low_thresh = 192*1024; | |
58 | ||
59 | /* Important NOTE! Fragment queue must be destroyed before MSL expires. | |
60 | * RFC791 is wrong proposing to prolongate timer each fragment arrival by TTL. | |
61 | */ | |
62 | int sysctl_ipfrag_time = IP_FRAG_TIME; | |
63 | ||
64 | struct ipfrag_skb_cb | |
65 | { | |
66 | struct inet_skb_parm h; | |
67 | int offset; | |
68 | }; | |
69 | ||
70 | #define FRAG_CB(skb) ((struct ipfrag_skb_cb*)((skb)->cb)) | |
71 | ||
72 | /* Describe an entry in the "incomplete datagrams" queue. */ | |
73 | struct ipq { | |
e7c8a41e | 74 | struct hlist_node list; |
1da177e4 LT |
75 | struct list_head lru_list; /* lru list member */ |
76 | u32 user; | |
77 | u32 saddr; | |
78 | u32 daddr; | |
79 | u16 id; | |
80 | u8 protocol; | |
81 | u8 last_in; | |
82 | #define COMPLETE 4 | |
83 | #define FIRST_IN 2 | |
84 | #define LAST_IN 1 | |
85 | ||
86 | struct sk_buff *fragments; /* linked list of received fragments */ | |
87 | int len; /* total length of original datagram */ | |
88 | int meat; | |
89 | spinlock_t lock; | |
90 | atomic_t refcnt; | |
91 | struct timer_list timer; /* when will this queue expire? */ | |
1da177e4 LT |
92 | int iif; |
93 | struct timeval stamp; | |
94 | }; | |
95 | ||
96 | /* Hash table. */ | |
97 | ||
98 | #define IPQ_HASHSZ 64 | |
99 | ||
100 | /* Per-bucket lock is easy to add now. */ | |
e7c8a41e | 101 | static struct hlist_head ipq_hash[IPQ_HASHSZ]; |
1da177e4 LT |
102 | static DEFINE_RWLOCK(ipfrag_lock); |
103 | static u32 ipfrag_hash_rnd; | |
104 | static LIST_HEAD(ipq_lru_list); | |
105 | int ip_frag_nqueues = 0; | |
106 | ||
107 | static __inline__ void __ipq_unlink(struct ipq *qp) | |
108 | { | |
e7c8a41e | 109 | hlist_del(&qp->list); |
1da177e4 LT |
110 | list_del(&qp->lru_list); |
111 | ip_frag_nqueues--; | |
112 | } | |
113 | ||
114 | static __inline__ void ipq_unlink(struct ipq *ipq) | |
115 | { | |
116 | write_lock(&ipfrag_lock); | |
117 | __ipq_unlink(ipq); | |
118 | write_unlock(&ipfrag_lock); | |
119 | } | |
120 | ||
121 | static unsigned int ipqhashfn(u16 id, u32 saddr, u32 daddr, u8 prot) | |
122 | { | |
123 | return jhash_3words((u32)id << 16 | prot, saddr, daddr, | |
124 | ipfrag_hash_rnd) & (IPQ_HASHSZ - 1); | |
125 | } | |
126 | ||
127 | static struct timer_list ipfrag_secret_timer; | |
128 | int sysctl_ipfrag_secret_interval = 10 * 60 * HZ; | |
129 | ||
130 | static void ipfrag_secret_rebuild(unsigned long dummy) | |
131 | { | |
132 | unsigned long now = jiffies; | |
133 | int i; | |
134 | ||
135 | write_lock(&ipfrag_lock); | |
136 | get_random_bytes(&ipfrag_hash_rnd, sizeof(u32)); | |
137 | for (i = 0; i < IPQ_HASHSZ; i++) { | |
138 | struct ipq *q; | |
e7c8a41e | 139 | struct hlist_node *p, *n; |
1da177e4 | 140 | |
e7c8a41e | 141 | hlist_for_each_entry_safe(q, p, n, &ipq_hash[i], list) { |
1da177e4 LT |
142 | unsigned int hval = ipqhashfn(q->id, q->saddr, |
143 | q->daddr, q->protocol); | |
144 | ||
145 | if (hval != i) { | |
e7c8a41e | 146 | hlist_del(&q->list); |
1da177e4 LT |
147 | |
148 | /* Relink to new hash chain. */ | |
e7c8a41e | 149 | hlist_add_head(&q->list, &ipq_hash[hval]); |
1da177e4 | 150 | } |
1da177e4 LT |
151 | } |
152 | } | |
153 | write_unlock(&ipfrag_lock); | |
154 | ||
155 | mod_timer(&ipfrag_secret_timer, now + sysctl_ipfrag_secret_interval); | |
156 | } | |
157 | ||
158 | atomic_t ip_frag_mem = ATOMIC_INIT(0); /* Memory used for fragments */ | |
159 | ||
160 | /* Memory Tracking Functions. */ | |
161 | static __inline__ void frag_kfree_skb(struct sk_buff *skb, int *work) | |
162 | { | |
163 | if (work) | |
164 | *work -= skb->truesize; | |
165 | atomic_sub(skb->truesize, &ip_frag_mem); | |
166 | kfree_skb(skb); | |
167 | } | |
168 | ||
169 | static __inline__ void frag_free_queue(struct ipq *qp, int *work) | |
170 | { | |
171 | if (work) | |
172 | *work -= sizeof(struct ipq); | |
173 | atomic_sub(sizeof(struct ipq), &ip_frag_mem); | |
174 | kfree(qp); | |
175 | } | |
176 | ||
177 | static __inline__ struct ipq *frag_alloc_queue(void) | |
178 | { | |
179 | struct ipq *qp = kmalloc(sizeof(struct ipq), GFP_ATOMIC); | |
180 | ||
181 | if(!qp) | |
182 | return NULL; | |
183 | atomic_add(sizeof(struct ipq), &ip_frag_mem); | |
184 | return qp; | |
185 | } | |
186 | ||
187 | ||
188 | /* Destruction primitives. */ | |
189 | ||
190 | /* Complete destruction of ipq. */ | |
191 | static void ip_frag_destroy(struct ipq *qp, int *work) | |
192 | { | |
193 | struct sk_buff *fp; | |
194 | ||
195 | BUG_TRAP(qp->last_in&COMPLETE); | |
196 | BUG_TRAP(del_timer(&qp->timer) == 0); | |
197 | ||
198 | /* Release all fragment data. */ | |
199 | fp = qp->fragments; | |
200 | while (fp) { | |
201 | struct sk_buff *xp = fp->next; | |
202 | ||
203 | frag_kfree_skb(fp, work); | |
204 | fp = xp; | |
205 | } | |
206 | ||
207 | /* Finally, release the queue descriptor itself. */ | |
208 | frag_free_queue(qp, work); | |
209 | } | |
210 | ||
211 | static __inline__ void ipq_put(struct ipq *ipq, int *work) | |
212 | { | |
213 | if (atomic_dec_and_test(&ipq->refcnt)) | |
214 | ip_frag_destroy(ipq, work); | |
215 | } | |
216 | ||
217 | /* Kill ipq entry. It is not destroyed immediately, | |
218 | * because caller (and someone more) holds reference count. | |
219 | */ | |
220 | static void ipq_kill(struct ipq *ipq) | |
221 | { | |
222 | if (del_timer(&ipq->timer)) | |
223 | atomic_dec(&ipq->refcnt); | |
224 | ||
225 | if (!(ipq->last_in & COMPLETE)) { | |
226 | ipq_unlink(ipq); | |
227 | atomic_dec(&ipq->refcnt); | |
228 | ipq->last_in |= COMPLETE; | |
229 | } | |
230 | } | |
231 | ||
232 | /* Memory limiting on fragments. Evictor trashes the oldest | |
233 | * fragment queue until we are back under the threshold. | |
234 | */ | |
235 | static void ip_evictor(void) | |
236 | { | |
237 | struct ipq *qp; | |
238 | struct list_head *tmp; | |
239 | int work; | |
240 | ||
241 | work = atomic_read(&ip_frag_mem) - sysctl_ipfrag_low_thresh; | |
242 | if (work <= 0) | |
243 | return; | |
244 | ||
245 | while (work > 0) { | |
246 | read_lock(&ipfrag_lock); | |
247 | if (list_empty(&ipq_lru_list)) { | |
248 | read_unlock(&ipfrag_lock); | |
249 | return; | |
250 | } | |
251 | tmp = ipq_lru_list.next; | |
252 | qp = list_entry(tmp, struct ipq, lru_list); | |
253 | atomic_inc(&qp->refcnt); | |
254 | read_unlock(&ipfrag_lock); | |
255 | ||
256 | spin_lock(&qp->lock); | |
257 | if (!(qp->last_in&COMPLETE)) | |
258 | ipq_kill(qp); | |
259 | spin_unlock(&qp->lock); | |
260 | ||
261 | ipq_put(qp, &work); | |
262 | IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | |
263 | } | |
264 | } | |
265 | ||
266 | /* | |
267 | * Oops, a fragment queue timed out. Kill it and send an ICMP reply. | |
268 | */ | |
269 | static void ip_expire(unsigned long arg) | |
270 | { | |
271 | struct ipq *qp = (struct ipq *) arg; | |
272 | ||
273 | spin_lock(&qp->lock); | |
274 | ||
275 | if (qp->last_in & COMPLETE) | |
276 | goto out; | |
277 | ||
278 | ipq_kill(qp); | |
279 | ||
280 | IP_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT); | |
281 | IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | |
282 | ||
283 | if ((qp->last_in&FIRST_IN) && qp->fragments != NULL) { | |
284 | struct sk_buff *head = qp->fragments; | |
285 | /* Send an ICMP "Fragment Reassembly Timeout" message. */ | |
286 | if ((head->dev = dev_get_by_index(qp->iif)) != NULL) { | |
287 | icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); | |
288 | dev_put(head->dev); | |
289 | } | |
290 | } | |
291 | out: | |
292 | spin_unlock(&qp->lock); | |
293 | ipq_put(qp, NULL); | |
294 | } | |
295 | ||
296 | /* Creation primitives. */ | |
297 | ||
298 | static struct ipq *ip_frag_intern(unsigned int hash, struct ipq *qp_in) | |
299 | { | |
300 | struct ipq *qp; | |
e7c8a41e YK |
301 | #ifdef CONFIG_SMP |
302 | struct hlist_node *n; | |
303 | #endif | |
1da177e4 LT |
304 | write_lock(&ipfrag_lock); |
305 | #ifdef CONFIG_SMP | |
306 | /* With SMP race we have to recheck hash table, because | |
307 | * such entry could be created on other cpu, while we | |
308 | * promoted read lock to write lock. | |
309 | */ | |
e7c8a41e | 310 | hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { |
1da177e4 LT |
311 | if(qp->id == qp_in->id && |
312 | qp->saddr == qp_in->saddr && | |
313 | qp->daddr == qp_in->daddr && | |
314 | qp->protocol == qp_in->protocol && | |
315 | qp->user == qp_in->user) { | |
316 | atomic_inc(&qp->refcnt); | |
317 | write_unlock(&ipfrag_lock); | |
318 | qp_in->last_in |= COMPLETE; | |
319 | ipq_put(qp_in, NULL); | |
320 | return qp; | |
321 | } | |
322 | } | |
323 | #endif | |
324 | qp = qp_in; | |
325 | ||
326 | if (!mod_timer(&qp->timer, jiffies + sysctl_ipfrag_time)) | |
327 | atomic_inc(&qp->refcnt); | |
328 | ||
329 | atomic_inc(&qp->refcnt); | |
e7c8a41e | 330 | hlist_add_head(&qp->list, &ipq_hash[hash]); |
1da177e4 LT |
331 | INIT_LIST_HEAD(&qp->lru_list); |
332 | list_add_tail(&qp->lru_list, &ipq_lru_list); | |
333 | ip_frag_nqueues++; | |
334 | write_unlock(&ipfrag_lock); | |
335 | return qp; | |
336 | } | |
337 | ||
338 | /* Add an entry to the 'ipq' queue for a newly received IP datagram. */ | |
339 | static struct ipq *ip_frag_create(unsigned hash, struct iphdr *iph, u32 user) | |
340 | { | |
341 | struct ipq *qp; | |
342 | ||
343 | if ((qp = frag_alloc_queue()) == NULL) | |
344 | goto out_nomem; | |
345 | ||
346 | qp->protocol = iph->protocol; | |
347 | qp->last_in = 0; | |
348 | qp->id = iph->id; | |
349 | qp->saddr = iph->saddr; | |
350 | qp->daddr = iph->daddr; | |
351 | qp->user = user; | |
352 | qp->len = 0; | |
353 | qp->meat = 0; | |
354 | qp->fragments = NULL; | |
355 | qp->iif = 0; | |
356 | ||
357 | /* Initialize a timer for this entry. */ | |
358 | init_timer(&qp->timer); | |
359 | qp->timer.data = (unsigned long) qp; /* pointer to queue */ | |
360 | qp->timer.function = ip_expire; /* expire function */ | |
361 | spin_lock_init(&qp->lock); | |
362 | atomic_set(&qp->refcnt, 1); | |
363 | ||
364 | return ip_frag_intern(hash, qp); | |
365 | ||
366 | out_nomem: | |
64ce2073 | 367 | LIMIT_NETDEBUG(KERN_ERR "ip_frag_create: no memory left !\n"); |
1da177e4 LT |
368 | return NULL; |
369 | } | |
370 | ||
371 | /* Find the correct entry in the "incomplete datagrams" queue for | |
372 | * this IP datagram, and create new one, if nothing is found. | |
373 | */ | |
374 | static inline struct ipq *ip_find(struct iphdr *iph, u32 user) | |
375 | { | |
376 | __u16 id = iph->id; | |
377 | __u32 saddr = iph->saddr; | |
378 | __u32 daddr = iph->daddr; | |
379 | __u8 protocol = iph->protocol; | |
380 | unsigned int hash = ipqhashfn(id, saddr, daddr, protocol); | |
381 | struct ipq *qp; | |
e7c8a41e | 382 | struct hlist_node *n; |
1da177e4 LT |
383 | |
384 | read_lock(&ipfrag_lock); | |
e7c8a41e | 385 | hlist_for_each_entry(qp, n, &ipq_hash[hash], list) { |
1da177e4 LT |
386 | if(qp->id == id && |
387 | qp->saddr == saddr && | |
388 | qp->daddr == daddr && | |
389 | qp->protocol == protocol && | |
390 | qp->user == user) { | |
391 | atomic_inc(&qp->refcnt); | |
392 | read_unlock(&ipfrag_lock); | |
393 | return qp; | |
394 | } | |
395 | } | |
396 | read_unlock(&ipfrag_lock); | |
397 | ||
398 | return ip_frag_create(hash, iph, user); | |
399 | } | |
400 | ||
401 | /* Add new segment to existing queue. */ | |
402 | static void ip_frag_queue(struct ipq *qp, struct sk_buff *skb) | |
403 | { | |
404 | struct sk_buff *prev, *next; | |
405 | int flags, offset; | |
406 | int ihl, end; | |
407 | ||
408 | if (qp->last_in & COMPLETE) | |
409 | goto err; | |
410 | ||
411 | offset = ntohs(skb->nh.iph->frag_off); | |
412 | flags = offset & ~IP_OFFSET; | |
413 | offset &= IP_OFFSET; | |
414 | offset <<= 3; /* offset is in 8-byte chunks */ | |
415 | ihl = skb->nh.iph->ihl * 4; | |
416 | ||
417 | /* Determine the position of this fragment. */ | |
418 | end = offset + skb->len - ihl; | |
419 | ||
420 | /* Is this the final fragment? */ | |
421 | if ((flags & IP_MF) == 0) { | |
422 | /* If we already have some bits beyond end | |
423 | * or have different end, the segment is corrrupted. | |
424 | */ | |
425 | if (end < qp->len || | |
426 | ((qp->last_in & LAST_IN) && end != qp->len)) | |
427 | goto err; | |
428 | qp->last_in |= LAST_IN; | |
429 | qp->len = end; | |
430 | } else { | |
431 | if (end&7) { | |
432 | end &= ~7; | |
433 | if (skb->ip_summed != CHECKSUM_UNNECESSARY) | |
434 | skb->ip_summed = CHECKSUM_NONE; | |
435 | } | |
436 | if (end > qp->len) { | |
437 | /* Some bits beyond end -> corruption. */ | |
438 | if (qp->last_in & LAST_IN) | |
439 | goto err; | |
440 | qp->len = end; | |
441 | } | |
442 | } | |
443 | if (end == offset) | |
444 | goto err; | |
445 | ||
446 | if (pskb_pull(skb, ihl) == NULL) | |
447 | goto err; | |
48bc41a4 | 448 | if (pskb_trim_rcsum(skb, end-offset)) |
1da177e4 LT |
449 | goto err; |
450 | ||
451 | /* Find out which fragments are in front and at the back of us | |
452 | * in the chain of fragments so far. We must know where to put | |
453 | * this fragment, right? | |
454 | */ | |
455 | prev = NULL; | |
456 | for(next = qp->fragments; next != NULL; next = next->next) { | |
457 | if (FRAG_CB(next)->offset >= offset) | |
458 | break; /* bingo! */ | |
459 | prev = next; | |
460 | } | |
461 | ||
462 | /* We found where to put this one. Check for overlap with | |
463 | * preceding fragment, and, if needed, align things so that | |
464 | * any overlaps are eliminated. | |
465 | */ | |
466 | if (prev) { | |
467 | int i = (FRAG_CB(prev)->offset + prev->len) - offset; | |
468 | ||
469 | if (i > 0) { | |
470 | offset += i; | |
471 | if (end <= offset) | |
472 | goto err; | |
473 | if (!pskb_pull(skb, i)) | |
474 | goto err; | |
475 | if (skb->ip_summed != CHECKSUM_UNNECESSARY) | |
476 | skb->ip_summed = CHECKSUM_NONE; | |
477 | } | |
478 | } | |
479 | ||
480 | while (next && FRAG_CB(next)->offset < end) { | |
481 | int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ | |
482 | ||
483 | if (i < next->len) { | |
484 | /* Eat head of the next overlapped fragment | |
485 | * and leave the loop. The next ones cannot overlap. | |
486 | */ | |
487 | if (!pskb_pull(next, i)) | |
488 | goto err; | |
489 | FRAG_CB(next)->offset += i; | |
490 | qp->meat -= i; | |
491 | if (next->ip_summed != CHECKSUM_UNNECESSARY) | |
492 | next->ip_summed = CHECKSUM_NONE; | |
493 | break; | |
494 | } else { | |
495 | struct sk_buff *free_it = next; | |
496 | ||
497 | /* Old fragmnet is completely overridden with | |
498 | * new one drop it. | |
499 | */ | |
500 | next = next->next; | |
501 | ||
502 | if (prev) | |
503 | prev->next = next; | |
504 | else | |
505 | qp->fragments = next; | |
506 | ||
507 | qp->meat -= free_it->len; | |
508 | frag_kfree_skb(free_it, NULL); | |
509 | } | |
510 | } | |
511 | ||
512 | FRAG_CB(skb)->offset = offset; | |
513 | ||
514 | /* Insert this fragment in the chain of fragments. */ | |
515 | skb->next = next; | |
516 | if (prev) | |
517 | prev->next = skb; | |
518 | else | |
519 | qp->fragments = skb; | |
520 | ||
521 | if (skb->dev) | |
522 | qp->iif = skb->dev->ifindex; | |
523 | skb->dev = NULL; | |
a61bbcf2 | 524 | skb_get_timestamp(skb, &qp->stamp); |
1da177e4 LT |
525 | qp->meat += skb->len; |
526 | atomic_add(skb->truesize, &ip_frag_mem); | |
527 | if (offset == 0) | |
528 | qp->last_in |= FIRST_IN; | |
529 | ||
530 | write_lock(&ipfrag_lock); | |
531 | list_move_tail(&qp->lru_list, &ipq_lru_list); | |
532 | write_unlock(&ipfrag_lock); | |
533 | ||
534 | return; | |
535 | ||
536 | err: | |
537 | kfree_skb(skb); | |
538 | } | |
539 | ||
540 | ||
541 | /* Build a new IP datagram from all its fragments. */ | |
542 | ||
543 | static struct sk_buff *ip_frag_reasm(struct ipq *qp, struct net_device *dev) | |
544 | { | |
545 | struct iphdr *iph; | |
546 | struct sk_buff *fp, *head = qp->fragments; | |
547 | int len; | |
548 | int ihlen; | |
549 | ||
550 | ipq_kill(qp); | |
551 | ||
552 | BUG_TRAP(head != NULL); | |
553 | BUG_TRAP(FRAG_CB(head)->offset == 0); | |
554 | ||
555 | /* Allocate a new buffer for the datagram. */ | |
556 | ihlen = head->nh.iph->ihl*4; | |
557 | len = ihlen + qp->len; | |
558 | ||
559 | if(len > 65535) | |
560 | goto out_oversize; | |
561 | ||
562 | /* Head of list must not be cloned. */ | |
563 | if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) | |
564 | goto out_nomem; | |
565 | ||
566 | /* If the first fragment is fragmented itself, we split | |
567 | * it to two chunks: the first with data and paged part | |
568 | * and the second, holding only fragments. */ | |
569 | if (skb_shinfo(head)->frag_list) { | |
570 | struct sk_buff *clone; | |
571 | int i, plen = 0; | |
572 | ||
573 | if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) | |
574 | goto out_nomem; | |
575 | clone->next = head->next; | |
576 | head->next = clone; | |
577 | skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; | |
578 | skb_shinfo(head)->frag_list = NULL; | |
579 | for (i=0; i<skb_shinfo(head)->nr_frags; i++) | |
580 | plen += skb_shinfo(head)->frags[i].size; | |
581 | clone->len = clone->data_len = head->data_len - plen; | |
582 | head->data_len -= clone->len; | |
583 | head->len -= clone->len; | |
584 | clone->csum = 0; | |
585 | clone->ip_summed = head->ip_summed; | |
586 | atomic_add(clone->truesize, &ip_frag_mem); | |
587 | } | |
588 | ||
589 | skb_shinfo(head)->frag_list = head->next; | |
590 | skb_push(head, head->data - head->nh.raw); | |
591 | atomic_sub(head->truesize, &ip_frag_mem); | |
592 | ||
593 | for (fp=head->next; fp; fp = fp->next) { | |
594 | head->data_len += fp->len; | |
595 | head->len += fp->len; | |
596 | if (head->ip_summed != fp->ip_summed) | |
597 | head->ip_summed = CHECKSUM_NONE; | |
598 | else if (head->ip_summed == CHECKSUM_HW) | |
599 | head->csum = csum_add(head->csum, fp->csum); | |
600 | head->truesize += fp->truesize; | |
601 | atomic_sub(fp->truesize, &ip_frag_mem); | |
602 | } | |
603 | ||
604 | head->next = NULL; | |
605 | head->dev = dev; | |
a61bbcf2 | 606 | skb_set_timestamp(head, &qp->stamp); |
1da177e4 LT |
607 | |
608 | iph = head->nh.iph; | |
609 | iph->frag_off = 0; | |
610 | iph->tot_len = htons(len); | |
611 | IP_INC_STATS_BH(IPSTATS_MIB_REASMOKS); | |
612 | qp->fragments = NULL; | |
613 | return head; | |
614 | ||
615 | out_nomem: | |
64ce2073 PM |
616 | LIMIT_NETDEBUG(KERN_ERR "IP: queue_glue: no memory for gluing " |
617 | "queue %p\n", qp); | |
1da177e4 LT |
618 | goto out_fail; |
619 | out_oversize: | |
620 | if (net_ratelimit()) | |
621 | printk(KERN_INFO | |
622 | "Oversized IP packet from %d.%d.%d.%d.\n", | |
623 | NIPQUAD(qp->saddr)); | |
624 | out_fail: | |
625 | IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | |
626 | return NULL; | |
627 | } | |
628 | ||
629 | /* Process an incoming IP datagram fragment. */ | |
630 | struct sk_buff *ip_defrag(struct sk_buff *skb, u32 user) | |
631 | { | |
632 | struct iphdr *iph = skb->nh.iph; | |
633 | struct ipq *qp; | |
634 | struct net_device *dev; | |
635 | ||
636 | IP_INC_STATS_BH(IPSTATS_MIB_REASMREQDS); | |
637 | ||
638 | /* Start by cleaning up the memory. */ | |
639 | if (atomic_read(&ip_frag_mem) > sysctl_ipfrag_high_thresh) | |
640 | ip_evictor(); | |
641 | ||
642 | dev = skb->dev; | |
643 | ||
644 | /* Lookup (or create) queue header */ | |
645 | if ((qp = ip_find(iph, user)) != NULL) { | |
646 | struct sk_buff *ret = NULL; | |
647 | ||
648 | spin_lock(&qp->lock); | |
649 | ||
650 | ip_frag_queue(qp, skb); | |
651 | ||
652 | if (qp->last_in == (FIRST_IN|LAST_IN) && | |
653 | qp->meat == qp->len) | |
654 | ret = ip_frag_reasm(qp, dev); | |
655 | ||
656 | spin_unlock(&qp->lock); | |
657 | ipq_put(qp, NULL); | |
658 | return ret; | |
659 | } | |
660 | ||
661 | IP_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); | |
662 | kfree_skb(skb); | |
663 | return NULL; | |
664 | } | |
665 | ||
666 | void ipfrag_init(void) | |
667 | { | |
668 | ipfrag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ | |
669 | (jiffies ^ (jiffies >> 6))); | |
670 | ||
671 | init_timer(&ipfrag_secret_timer); | |
672 | ipfrag_secret_timer.function = ipfrag_secret_rebuild; | |
673 | ipfrag_secret_timer.expires = jiffies + sysctl_ipfrag_secret_interval; | |
674 | add_timer(&ipfrag_secret_timer); | |
675 | } | |
676 | ||
677 | EXPORT_SYMBOL(ip_defrag); |