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Commit | Line | Data |
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7eb95156 PE |
1 | /* |
2 | * inet fragments management | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Pavel Emelyanov <xemul@openvz.org> | |
10 | * Started as consolidation of ipv4/ip_fragment.c, | |
11 | * ipv6/reassembly. and ipv6 nf conntrack reassembly | |
12 | */ | |
13 | ||
14 | #include <linux/list.h> | |
15 | #include <linux/spinlock.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/timer.h> | |
18 | #include <linux/mm.h> | |
321a3a99 | 19 | #include <linux/random.h> |
1e4b8287 PE |
20 | #include <linux/skbuff.h> |
21 | #include <linux/rtnetlink.h> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
7eb95156 | 23 | |
5a3da1fe | 24 | #include <net/sock.h> |
7eb95156 | 25 | #include <net/inet_frag.h> |
be991971 HFS |
26 | #include <net/inet_ecn.h> |
27 | ||
b13d3cbf FW |
28 | #define INETFRAGS_EVICT_BUCKETS 128 |
29 | #define INETFRAGS_EVICT_MAX 512 | |
30 | ||
e3a57d18 FW |
31 | /* don't rebuild inetfrag table with new secret more often than this */ |
32 | #define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ) | |
33 | ||
be991971 HFS |
34 | /* Given the OR values of all fragments, apply RFC 3168 5.3 requirements |
35 | * Value : 0xff if frame should be dropped. | |
36 | * 0 or INET_ECN_CE value, to be ORed in to final iph->tos field | |
37 | */ | |
38 | const u8 ip_frag_ecn_table[16] = { | |
39 | /* at least one fragment had CE, and others ECT_0 or ECT_1 */ | |
40 | [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE, | |
41 | [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE, | |
42 | [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE, | |
43 | ||
44 | /* invalid combinations : drop frame */ | |
45 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff, | |
46 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff, | |
47 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff, | |
48 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, | |
49 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff, | |
50 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff, | |
51 | [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff, | |
52 | }; | |
53 | EXPORT_SYMBOL(ip_frag_ecn_table); | |
7eb95156 | 54 | |
fb3cfe6e FW |
55 | static unsigned int |
56 | inet_frag_hashfn(const struct inet_frags *f, const struct inet_frag_queue *q) | |
57 | { | |
58 | return f->hashfn(q) & (INETFRAGS_HASHSZ - 1); | |
59 | } | |
60 | ||
e3a57d18 FW |
61 | static bool inet_frag_may_rebuild(struct inet_frags *f) |
62 | { | |
63 | return time_after(jiffies, | |
64 | f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL); | |
65 | } | |
66 | ||
67 | static void inet_frag_secret_rebuild(struct inet_frags *f) | |
321a3a99 | 68 | { |
321a3a99 PE |
69 | int i; |
70 | ||
ab1c724f | 71 | write_seqlock_bh(&f->rnd_seqlock); |
e3a57d18 FW |
72 | |
73 | if (!inet_frag_may_rebuild(f)) | |
74 | goto out; | |
19952cc4 | 75 | |
321a3a99 | 76 | get_random_bytes(&f->rnd, sizeof(u32)); |
e3a57d18 | 77 | |
321a3a99 | 78 | for (i = 0; i < INETFRAGS_HASHSZ; i++) { |
19952cc4 | 79 | struct inet_frag_bucket *hb; |
321a3a99 | 80 | struct inet_frag_queue *q; |
b67bfe0d | 81 | struct hlist_node *n; |
321a3a99 | 82 | |
19952cc4 | 83 | hb = &f->hash[i]; |
ab1c724f FW |
84 | spin_lock(&hb->chain_lock); |
85 | ||
19952cc4 | 86 | hlist_for_each_entry_safe(q, n, &hb->chain, list) { |
fb3cfe6e | 87 | unsigned int hval = inet_frag_hashfn(f, q); |
321a3a99 PE |
88 | |
89 | if (hval != i) { | |
19952cc4 JDB |
90 | struct inet_frag_bucket *hb_dest; |
91 | ||
321a3a99 PE |
92 | hlist_del(&q->list); |
93 | ||
94 | /* Relink to new hash chain. */ | |
19952cc4 | 95 | hb_dest = &f->hash[hval]; |
ab1c724f FW |
96 | |
97 | /* This is the only place where we take | |
98 | * another chain_lock while already holding | |
99 | * one. As this will not run concurrently, | |
100 | * we cannot deadlock on hb_dest lock below, if its | |
101 | * already locked it will be released soon since | |
102 | * other caller cannot be waiting for hb lock | |
103 | * that we've taken above. | |
104 | */ | |
105 | spin_lock_nested(&hb_dest->chain_lock, | |
106 | SINGLE_DEPTH_NESTING); | |
19952cc4 | 107 | hlist_add_head(&q->list, &hb_dest->chain); |
ab1c724f | 108 | spin_unlock(&hb_dest->chain_lock); |
321a3a99 PE |
109 | } |
110 | } | |
ab1c724f | 111 | spin_unlock(&hb->chain_lock); |
321a3a99 | 112 | } |
321a3a99 | 113 | |
e3a57d18 FW |
114 | f->rebuild = false; |
115 | f->last_rebuild_jiffies = jiffies; | |
116 | out: | |
ab1c724f | 117 | write_sequnlock_bh(&f->rnd_seqlock); |
321a3a99 PE |
118 | } |
119 | ||
b13d3cbf FW |
120 | static bool inet_fragq_should_evict(const struct inet_frag_queue *q) |
121 | { | |
122 | return q->net->low_thresh == 0 || | |
123 | frag_mem_limit(q->net) >= q->net->low_thresh; | |
124 | } | |
125 | ||
126 | static unsigned int | |
127 | inet_evict_bucket(struct inet_frags *f, struct inet_frag_bucket *hb) | |
128 | { | |
129 | struct inet_frag_queue *fq; | |
130 | struct hlist_node *n; | |
131 | unsigned int evicted = 0; | |
132 | HLIST_HEAD(expired); | |
133 | ||
134 | evict_again: | |
135 | spin_lock(&hb->chain_lock); | |
136 | ||
137 | hlist_for_each_entry_safe(fq, n, &hb->chain, list) { | |
138 | if (!inet_fragq_should_evict(fq)) | |
139 | continue; | |
140 | ||
141 | if (!del_timer(&fq->timer)) { | |
142 | /* q expiring right now thus increment its refcount so | |
143 | * it won't be freed under us and wait until the timer | |
144 | * has finished executing then destroy it | |
145 | */ | |
146 | atomic_inc(&fq->refcnt); | |
147 | spin_unlock(&hb->chain_lock); | |
148 | del_timer_sync(&fq->timer); | |
b13d3cbf FW |
149 | inet_frag_put(fq, f); |
150 | goto evict_again; | |
151 | } | |
152 | ||
06aa8b8a | 153 | fq->flags |= INET_FRAG_EVICTED; |
b13d3cbf FW |
154 | hlist_del(&fq->list); |
155 | hlist_add_head(&fq->list, &expired); | |
156 | ++evicted; | |
157 | } | |
158 | ||
159 | spin_unlock(&hb->chain_lock); | |
160 | ||
161 | hlist_for_each_entry_safe(fq, n, &expired, list) | |
162 | f->frag_expire((unsigned long) fq); | |
163 | ||
164 | return evicted; | |
165 | } | |
166 | ||
167 | static void inet_frag_worker(struct work_struct *work) | |
168 | { | |
169 | unsigned int budget = INETFRAGS_EVICT_BUCKETS; | |
170 | unsigned int i, evicted = 0; | |
171 | struct inet_frags *f; | |
172 | ||
173 | f = container_of(work, struct inet_frags, frags_work); | |
174 | ||
175 | BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ); | |
176 | ||
ab1c724f | 177 | local_bh_disable(); |
b13d3cbf FW |
178 | |
179 | for (i = ACCESS_ONCE(f->next_bucket); budget; --budget) { | |
180 | evicted += inet_evict_bucket(f, &f->hash[i]); | |
181 | i = (i + 1) & (INETFRAGS_HASHSZ - 1); | |
182 | if (evicted > INETFRAGS_EVICT_MAX) | |
183 | break; | |
184 | } | |
185 | ||
186 | f->next_bucket = i; | |
187 | ||
ab1c724f FW |
188 | local_bh_enable(); |
189 | ||
e3a57d18 FW |
190 | if (f->rebuild && inet_frag_may_rebuild(f)) |
191 | inet_frag_secret_rebuild(f); | |
b13d3cbf FW |
192 | } |
193 | ||
194 | static void inet_frag_schedule_worker(struct inet_frags *f) | |
195 | { | |
196 | if (unlikely(!work_pending(&f->frags_work))) | |
197 | schedule_work(&f->frags_work); | |
198 | } | |
199 | ||
d4ad4d22 | 200 | int inet_frags_init(struct inet_frags *f) |
7eb95156 PE |
201 | { |
202 | int i; | |
203 | ||
b13d3cbf FW |
204 | INIT_WORK(&f->frags_work, inet_frag_worker); |
205 | ||
19952cc4 JDB |
206 | for (i = 0; i < INETFRAGS_HASHSZ; i++) { |
207 | struct inet_frag_bucket *hb = &f->hash[i]; | |
7eb95156 | 208 | |
19952cc4 JDB |
209 | spin_lock_init(&hb->chain_lock); |
210 | INIT_HLIST_HEAD(&hb->chain); | |
211 | } | |
ab1c724f FW |
212 | |
213 | seqlock_init(&f->rnd_seqlock); | |
e3a57d18 | 214 | f->last_rebuild_jiffies = 0; |
d4ad4d22 NA |
215 | f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0, |
216 | NULL); | |
217 | if (!f->frags_cachep) | |
218 | return -ENOMEM; | |
219 | ||
220 | return 0; | |
7eb95156 PE |
221 | } |
222 | EXPORT_SYMBOL(inet_frags_init); | |
223 | ||
e5a2bb84 PE |
224 | void inet_frags_init_net(struct netns_frags *nf) |
225 | { | |
d433673e | 226 | init_frag_mem_limit(nf); |
e5a2bb84 PE |
227 | } |
228 | EXPORT_SYMBOL(inet_frags_init_net); | |
229 | ||
7eb95156 PE |
230 | void inet_frags_fini(struct inet_frags *f) |
231 | { | |
b13d3cbf | 232 | cancel_work_sync(&f->frags_work); |
d4ad4d22 | 233 | kmem_cache_destroy(f->frags_cachep); |
7eb95156 PE |
234 | } |
235 | EXPORT_SYMBOL(inet_frags_fini); | |
277e650d | 236 | |
81566e83 PE |
237 | void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f) |
238 | { | |
ab1c724f | 239 | unsigned int seq; |
b13d3cbf FW |
240 | int i; |
241 | ||
81566e83 | 242 | nf->low_thresh = 0; |
ab1c724f | 243 | local_bh_disable(); |
e8e16b70 | 244 | |
ab1c724f FW |
245 | evict_again: |
246 | seq = read_seqbegin(&f->rnd_seqlock); | |
b13d3cbf FW |
247 | |
248 | for (i = 0; i < INETFRAGS_HASHSZ ; i++) | |
249 | inet_evict_bucket(f, &f->hash[i]); | |
250 | ||
ab1c724f FW |
251 | if (read_seqretry(&f->rnd_seqlock, seq)) |
252 | goto evict_again; | |
253 | ||
254 | local_bh_enable(); | |
6d7b857d JDB |
255 | |
256 | percpu_counter_destroy(&nf->mem); | |
81566e83 PE |
257 | } |
258 | EXPORT_SYMBOL(inet_frags_exit_net); | |
259 | ||
ab1c724f FW |
260 | static struct inet_frag_bucket * |
261 | get_frag_bucket_locked(struct inet_frag_queue *fq, struct inet_frags *f) | |
262 | __acquires(hb->chain_lock) | |
277e650d | 263 | { |
19952cc4 | 264 | struct inet_frag_bucket *hb; |
ab1c724f FW |
265 | unsigned int seq, hash; |
266 | ||
267 | restart: | |
268 | seq = read_seqbegin(&f->rnd_seqlock); | |
19952cc4 | 269 | |
fb3cfe6e | 270 | hash = inet_frag_hashfn(f, fq); |
19952cc4 JDB |
271 | hb = &f->hash[hash]; |
272 | ||
273 | spin_lock(&hb->chain_lock); | |
ab1c724f FW |
274 | if (read_seqretry(&f->rnd_seqlock, seq)) { |
275 | spin_unlock(&hb->chain_lock); | |
276 | goto restart; | |
277 | } | |
278 | ||
279 | return hb; | |
280 | } | |
281 | ||
282 | static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f) | |
283 | { | |
284 | struct inet_frag_bucket *hb; | |
285 | ||
286 | hb = get_frag_bucket_locked(fq, f); | |
65ba1f1e NA |
287 | if (!(fq->flags & INET_FRAG_EVICTED)) |
288 | hlist_del(&fq->list); | |
19952cc4 | 289 | spin_unlock(&hb->chain_lock); |
277e650d PE |
290 | } |
291 | ||
292 | void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f) | |
293 | { | |
294 | if (del_timer(&fq->timer)) | |
295 | atomic_dec(&fq->refcnt); | |
296 | ||
06aa8b8a | 297 | if (!(fq->flags & INET_FRAG_COMPLETE)) { |
277e650d PE |
298 | fq_unlink(fq, f); |
299 | atomic_dec(&fq->refcnt); | |
06aa8b8a | 300 | fq->flags |= INET_FRAG_COMPLETE; |
277e650d PE |
301 | } |
302 | } | |
277e650d | 303 | EXPORT_SYMBOL(inet_frag_kill); |
1e4b8287 | 304 | |
6ddc0822 | 305 | static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f, |
06aa8b8a | 306 | struct sk_buff *skb) |
1e4b8287 | 307 | { |
1e4b8287 PE |
308 | if (f->skb_free) |
309 | f->skb_free(skb); | |
310 | kfree_skb(skb); | |
311 | } | |
312 | ||
3fd588eb | 313 | void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f) |
1e4b8287 PE |
314 | { |
315 | struct sk_buff *fp; | |
6ddc0822 | 316 | struct netns_frags *nf; |
d433673e | 317 | unsigned int sum, sum_truesize = 0; |
1e4b8287 | 318 | |
06aa8b8a | 319 | WARN_ON(!(q->flags & INET_FRAG_COMPLETE)); |
547b792c | 320 | WARN_ON(del_timer(&q->timer) != 0); |
1e4b8287 PE |
321 | |
322 | /* Release all fragment data. */ | |
323 | fp = q->fragments; | |
6ddc0822 | 324 | nf = q->net; |
1e4b8287 PE |
325 | while (fp) { |
326 | struct sk_buff *xp = fp->next; | |
327 | ||
d433673e JDB |
328 | sum_truesize += fp->truesize; |
329 | frag_kfree_skb(nf, f, fp); | |
1e4b8287 PE |
330 | fp = xp; |
331 | } | |
d433673e | 332 | sum = sum_truesize + f->qsize; |
d433673e | 333 | sub_frag_mem_limit(q, sum); |
1e4b8287 | 334 | |
c9547709 PE |
335 | if (f->destructor) |
336 | f->destructor(q); | |
d4ad4d22 | 337 | kmem_cache_free(f->frags_cachep, q); |
1e4b8287 PE |
338 | } |
339 | EXPORT_SYMBOL(inet_frag_destroy); | |
8e7999c4 | 340 | |
ac18e750 | 341 | static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf, |
f926e236 NA |
342 | struct inet_frag_queue *qp_in, |
343 | struct inet_frags *f, | |
344 | void *arg) | |
2588fe1d | 345 | { |
ab1c724f | 346 | struct inet_frag_bucket *hb = get_frag_bucket_locked(qp_in, f); |
2588fe1d | 347 | struct inet_frag_queue *qp; |
19952cc4 | 348 | |
2588fe1d PE |
349 | #ifdef CONFIG_SMP |
350 | /* With SMP race we have to recheck hash table, because | |
ab1c724f FW |
351 | * such entry could have been created on other cpu before |
352 | * we acquired hash bucket lock. | |
2588fe1d | 353 | */ |
19952cc4 | 354 | hlist_for_each_entry(qp, &hb->chain, list) { |
ac18e750 | 355 | if (qp->net == nf && f->match(qp, arg)) { |
2588fe1d | 356 | atomic_inc(&qp->refcnt); |
19952cc4 | 357 | spin_unlock(&hb->chain_lock); |
06aa8b8a | 358 | qp_in->flags |= INET_FRAG_COMPLETE; |
2588fe1d PE |
359 | inet_frag_put(qp_in, f); |
360 | return qp; | |
361 | } | |
362 | } | |
363 | #endif | |
364 | qp = qp_in; | |
b2fd5321 | 365 | if (!mod_timer(&qp->timer, jiffies + nf->timeout)) |
2588fe1d PE |
366 | atomic_inc(&qp->refcnt); |
367 | ||
368 | atomic_inc(&qp->refcnt); | |
19952cc4 | 369 | hlist_add_head(&qp->list, &hb->chain); |
3fd588eb | 370 | |
19952cc4 | 371 | spin_unlock(&hb->chain_lock); |
24b9bf43 | 372 | |
2588fe1d PE |
373 | return qp; |
374 | } | |
e521db9d | 375 | |
ac18e750 | 376 | static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf, |
f926e236 NA |
377 | struct inet_frags *f, |
378 | void *arg) | |
e521db9d PE |
379 | { |
380 | struct inet_frag_queue *q; | |
381 | ||
b13d3cbf FW |
382 | if (frag_mem_limit(nf) > nf->high_thresh) { |
383 | inet_frag_schedule_worker(f); | |
86e93e47 | 384 | return NULL; |
b13d3cbf | 385 | } |
86e93e47 | 386 | |
d4ad4d22 | 387 | q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC); |
e521db9d PE |
388 | if (q == NULL) |
389 | return NULL; | |
390 | ||
54db0cc2 | 391 | q->net = nf; |
c6fda282 | 392 | f->constructor(q, arg); |
d433673e JDB |
393 | add_frag_mem_limit(q, f->qsize); |
394 | ||
e521db9d PE |
395 | setup_timer(&q->timer, f->frag_expire, (unsigned long)q); |
396 | spin_lock_init(&q->lock); | |
397 | atomic_set(&q->refcnt, 1); | |
398 | ||
399 | return q; | |
400 | } | |
c6fda282 | 401 | |
ac18e750 | 402 | static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf, |
f926e236 NA |
403 | struct inet_frags *f, |
404 | void *arg) | |
c6fda282 PE |
405 | { |
406 | struct inet_frag_queue *q; | |
407 | ||
ac18e750 | 408 | q = inet_frag_alloc(nf, f, arg); |
c6fda282 PE |
409 | if (q == NULL) |
410 | return NULL; | |
411 | ||
9a375803 | 412 | return inet_frag_intern(nf, q, f, arg); |
c6fda282 | 413 | } |
abd6523d | 414 | |
ac18e750 | 415 | struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, |
f926e236 NA |
416 | struct inet_frags *f, void *key, |
417 | unsigned int hash) | |
abd6523d | 418 | { |
19952cc4 | 419 | struct inet_frag_bucket *hb; |
abd6523d | 420 | struct inet_frag_queue *q; |
5a3da1fe | 421 | int depth = 0; |
abd6523d | 422 | |
b13d3cbf FW |
423 | if (frag_mem_limit(nf) > nf->low_thresh) |
424 | inet_frag_schedule_worker(f); | |
86e93e47 | 425 | |
fb3cfe6e | 426 | hash &= (INETFRAGS_HASHSZ - 1); |
19952cc4 JDB |
427 | hb = &f->hash[hash]; |
428 | ||
429 | spin_lock(&hb->chain_lock); | |
430 | hlist_for_each_entry(q, &hb->chain, list) { | |
ac18e750 | 431 | if (q->net == nf && f->match(q, key)) { |
abd6523d | 432 | atomic_inc(&q->refcnt); |
19952cc4 | 433 | spin_unlock(&hb->chain_lock); |
abd6523d PE |
434 | return q; |
435 | } | |
5a3da1fe | 436 | depth++; |
abd6523d | 437 | } |
19952cc4 | 438 | spin_unlock(&hb->chain_lock); |
abd6523d | 439 | |
5a3da1fe HFS |
440 | if (depth <= INETFRAGS_MAXDEPTH) |
441 | return inet_frag_create(nf, f, key); | |
e3a57d18 FW |
442 | |
443 | if (inet_frag_may_rebuild(f)) { | |
ab1c724f FW |
444 | if (!f->rebuild) |
445 | f->rebuild = true; | |
e3a57d18 FW |
446 | inet_frag_schedule_worker(f); |
447 | } | |
448 | ||
449 | return ERR_PTR(-ENOBUFS); | |
abd6523d PE |
450 | } |
451 | EXPORT_SYMBOL(inet_frag_find); | |
5a3da1fe HFS |
452 | |
453 | void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, | |
454 | const char *prefix) | |
455 | { | |
456 | static const char msg[] = "inet_frag_find: Fragment hash bucket" | |
457 | " list length grew over limit " __stringify(INETFRAGS_MAXDEPTH) | |
458 | ". Dropping fragment.\n"; | |
459 | ||
460 | if (PTR_ERR(q) == -ENOBUFS) | |
ba7a46f1 | 461 | net_dbg_ratelimited("%s%s", prefix, msg); |
5a3da1fe HFS |
462 | } |
463 | EXPORT_SYMBOL(inet_frag_maybe_warn_overflow); |