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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 | ||
b13d3cbf FW |
134 | spin_lock(&hb->chain_lock); |
135 | ||
136 | hlist_for_each_entry_safe(fq, n, &hb->chain, list) { | |
137 | if (!inet_fragq_should_evict(fq)) | |
138 | continue; | |
139 | ||
5719b296 FW |
140 | if (!del_timer(&fq->timer)) |
141 | continue; | |
b13d3cbf | 142 | |
d1fe1944 | 143 | hlist_add_head(&fq->list_evictor, &expired); |
b13d3cbf FW |
144 | ++evicted; |
145 | } | |
146 | ||
147 | spin_unlock(&hb->chain_lock); | |
148 | ||
d1fe1944 | 149 | hlist_for_each_entry_safe(fq, n, &expired, list_evictor) |
b13d3cbf FW |
150 | f->frag_expire((unsigned long) fq); |
151 | ||
152 | return evicted; | |
153 | } | |
154 | ||
155 | static void inet_frag_worker(struct work_struct *work) | |
156 | { | |
157 | unsigned int budget = INETFRAGS_EVICT_BUCKETS; | |
158 | unsigned int i, evicted = 0; | |
159 | struct inet_frags *f; | |
160 | ||
161 | f = container_of(work, struct inet_frags, frags_work); | |
162 | ||
163 | BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ); | |
164 | ||
ab1c724f | 165 | local_bh_disable(); |
b13d3cbf FW |
166 | |
167 | for (i = ACCESS_ONCE(f->next_bucket); budget; --budget) { | |
168 | evicted += inet_evict_bucket(f, &f->hash[i]); | |
169 | i = (i + 1) & (INETFRAGS_HASHSZ - 1); | |
170 | if (evicted > INETFRAGS_EVICT_MAX) | |
171 | break; | |
172 | } | |
173 | ||
174 | f->next_bucket = i; | |
175 | ||
ab1c724f FW |
176 | local_bh_enable(); |
177 | ||
e3a57d18 FW |
178 | if (f->rebuild && inet_frag_may_rebuild(f)) |
179 | inet_frag_secret_rebuild(f); | |
b13d3cbf FW |
180 | } |
181 | ||
182 | static void inet_frag_schedule_worker(struct inet_frags *f) | |
183 | { | |
184 | if (unlikely(!work_pending(&f->frags_work))) | |
185 | schedule_work(&f->frags_work); | |
186 | } | |
187 | ||
d4ad4d22 | 188 | int inet_frags_init(struct inet_frags *f) |
7eb95156 PE |
189 | { |
190 | int i; | |
191 | ||
b13d3cbf FW |
192 | INIT_WORK(&f->frags_work, inet_frag_worker); |
193 | ||
19952cc4 JDB |
194 | for (i = 0; i < INETFRAGS_HASHSZ; i++) { |
195 | struct inet_frag_bucket *hb = &f->hash[i]; | |
7eb95156 | 196 | |
19952cc4 JDB |
197 | spin_lock_init(&hb->chain_lock); |
198 | INIT_HLIST_HEAD(&hb->chain); | |
199 | } | |
ab1c724f FW |
200 | |
201 | seqlock_init(&f->rnd_seqlock); | |
e3a57d18 | 202 | f->last_rebuild_jiffies = 0; |
d4ad4d22 NA |
203 | f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0, |
204 | NULL); | |
205 | if (!f->frags_cachep) | |
206 | return -ENOMEM; | |
207 | ||
208 | return 0; | |
7eb95156 PE |
209 | } |
210 | EXPORT_SYMBOL(inet_frags_init); | |
211 | ||
e5a2bb84 PE |
212 | void inet_frags_init_net(struct netns_frags *nf) |
213 | { | |
d433673e | 214 | init_frag_mem_limit(nf); |
e5a2bb84 PE |
215 | } |
216 | EXPORT_SYMBOL(inet_frags_init_net); | |
217 | ||
7eb95156 PE |
218 | void inet_frags_fini(struct inet_frags *f) |
219 | { | |
b13d3cbf | 220 | cancel_work_sync(&f->frags_work); |
d4ad4d22 | 221 | kmem_cache_destroy(f->frags_cachep); |
7eb95156 PE |
222 | } |
223 | EXPORT_SYMBOL(inet_frags_fini); | |
277e650d | 224 | |
81566e83 PE |
225 | void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f) |
226 | { | |
ab1c724f | 227 | unsigned int seq; |
b13d3cbf FW |
228 | int i; |
229 | ||
81566e83 | 230 | nf->low_thresh = 0; |
e8e16b70 | 231 | |
ab1c724f | 232 | evict_again: |
5719b296 | 233 | local_bh_disable(); |
ab1c724f | 234 | seq = read_seqbegin(&f->rnd_seqlock); |
b13d3cbf FW |
235 | |
236 | for (i = 0; i < INETFRAGS_HASHSZ ; i++) | |
237 | inet_evict_bucket(f, &f->hash[i]); | |
238 | ||
ab1c724f | 239 | local_bh_enable(); |
5719b296 FW |
240 | cond_resched(); |
241 | ||
242 | if (read_seqretry(&f->rnd_seqlock, seq) || | |
243 | percpu_counter_sum(&nf->mem)) | |
244 | goto evict_again; | |
6d7b857d JDB |
245 | |
246 | percpu_counter_destroy(&nf->mem); | |
81566e83 PE |
247 | } |
248 | EXPORT_SYMBOL(inet_frags_exit_net); | |
249 | ||
ab1c724f FW |
250 | static struct inet_frag_bucket * |
251 | get_frag_bucket_locked(struct inet_frag_queue *fq, struct inet_frags *f) | |
252 | __acquires(hb->chain_lock) | |
277e650d | 253 | { |
19952cc4 | 254 | struct inet_frag_bucket *hb; |
ab1c724f FW |
255 | unsigned int seq, hash; |
256 | ||
257 | restart: | |
258 | seq = read_seqbegin(&f->rnd_seqlock); | |
19952cc4 | 259 | |
fb3cfe6e | 260 | hash = inet_frag_hashfn(f, fq); |
19952cc4 JDB |
261 | hb = &f->hash[hash]; |
262 | ||
263 | spin_lock(&hb->chain_lock); | |
ab1c724f FW |
264 | if (read_seqretry(&f->rnd_seqlock, seq)) { |
265 | spin_unlock(&hb->chain_lock); | |
266 | goto restart; | |
267 | } | |
268 | ||
269 | return hb; | |
270 | } | |
271 | ||
272 | static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f) | |
273 | { | |
274 | struct inet_frag_bucket *hb; | |
275 | ||
276 | hb = get_frag_bucket_locked(fq, f); | |
d1fe1944 | 277 | hlist_del(&fq->list); |
5719b296 | 278 | fq->flags |= INET_FRAG_COMPLETE; |
19952cc4 | 279 | spin_unlock(&hb->chain_lock); |
277e650d PE |
280 | } |
281 | ||
282 | void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f) | |
283 | { | |
284 | if (del_timer(&fq->timer)) | |
285 | atomic_dec(&fq->refcnt); | |
286 | ||
06aa8b8a | 287 | if (!(fq->flags & INET_FRAG_COMPLETE)) { |
277e650d PE |
288 | fq_unlink(fq, f); |
289 | atomic_dec(&fq->refcnt); | |
277e650d PE |
290 | } |
291 | } | |
277e650d | 292 | EXPORT_SYMBOL(inet_frag_kill); |
1e4b8287 | 293 | |
6ddc0822 | 294 | static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f, |
06aa8b8a | 295 | struct sk_buff *skb) |
1e4b8287 | 296 | { |
1e4b8287 PE |
297 | if (f->skb_free) |
298 | f->skb_free(skb); | |
299 | kfree_skb(skb); | |
300 | } | |
301 | ||
3fd588eb | 302 | void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f) |
1e4b8287 PE |
303 | { |
304 | struct sk_buff *fp; | |
6ddc0822 | 305 | struct netns_frags *nf; |
d433673e | 306 | unsigned int sum, sum_truesize = 0; |
1e4b8287 | 307 | |
06aa8b8a | 308 | WARN_ON(!(q->flags & INET_FRAG_COMPLETE)); |
547b792c | 309 | WARN_ON(del_timer(&q->timer) != 0); |
1e4b8287 PE |
310 | |
311 | /* Release all fragment data. */ | |
312 | fp = q->fragments; | |
6ddc0822 | 313 | nf = q->net; |
1e4b8287 PE |
314 | while (fp) { |
315 | struct sk_buff *xp = fp->next; | |
316 | ||
d433673e JDB |
317 | sum_truesize += fp->truesize; |
318 | frag_kfree_skb(nf, f, fp); | |
1e4b8287 PE |
319 | fp = xp; |
320 | } | |
d433673e | 321 | sum = sum_truesize + f->qsize; |
1e4b8287 | 322 | |
c9547709 PE |
323 | if (f->destructor) |
324 | f->destructor(q); | |
d4ad4d22 | 325 | kmem_cache_free(f->frags_cachep, q); |
5719b296 FW |
326 | |
327 | sub_frag_mem_limit(nf, sum); | |
1e4b8287 PE |
328 | } |
329 | EXPORT_SYMBOL(inet_frag_destroy); | |
8e7999c4 | 330 | |
ac18e750 | 331 | static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf, |
f926e236 NA |
332 | struct inet_frag_queue *qp_in, |
333 | struct inet_frags *f, | |
334 | void *arg) | |
2588fe1d | 335 | { |
ab1c724f | 336 | struct inet_frag_bucket *hb = get_frag_bucket_locked(qp_in, f); |
2588fe1d | 337 | struct inet_frag_queue *qp; |
19952cc4 | 338 | |
2588fe1d PE |
339 | #ifdef CONFIG_SMP |
340 | /* With SMP race we have to recheck hash table, because | |
ab1c724f FW |
341 | * such entry could have been created on other cpu before |
342 | * we acquired hash bucket lock. | |
2588fe1d | 343 | */ |
19952cc4 | 344 | hlist_for_each_entry(qp, &hb->chain, list) { |
ac18e750 | 345 | if (qp->net == nf && f->match(qp, arg)) { |
2588fe1d | 346 | atomic_inc(&qp->refcnt); |
19952cc4 | 347 | spin_unlock(&hb->chain_lock); |
06aa8b8a | 348 | qp_in->flags |= INET_FRAG_COMPLETE; |
2588fe1d PE |
349 | inet_frag_put(qp_in, f); |
350 | return qp; | |
351 | } | |
352 | } | |
353 | #endif | |
354 | qp = qp_in; | |
b2fd5321 | 355 | if (!mod_timer(&qp->timer, jiffies + nf->timeout)) |
2588fe1d PE |
356 | atomic_inc(&qp->refcnt); |
357 | ||
358 | atomic_inc(&qp->refcnt); | |
19952cc4 | 359 | hlist_add_head(&qp->list, &hb->chain); |
3fd588eb | 360 | |
19952cc4 | 361 | spin_unlock(&hb->chain_lock); |
24b9bf43 | 362 | |
2588fe1d PE |
363 | return qp; |
364 | } | |
e521db9d | 365 | |
ac18e750 | 366 | static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf, |
f926e236 NA |
367 | struct inet_frags *f, |
368 | void *arg) | |
e521db9d PE |
369 | { |
370 | struct inet_frag_queue *q; | |
371 | ||
b13d3cbf FW |
372 | if (frag_mem_limit(nf) > nf->high_thresh) { |
373 | inet_frag_schedule_worker(f); | |
86e93e47 | 374 | return NULL; |
b13d3cbf | 375 | } |
86e93e47 | 376 | |
d4ad4d22 | 377 | q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC); |
51456b29 | 378 | if (!q) |
e521db9d PE |
379 | return NULL; |
380 | ||
54db0cc2 | 381 | q->net = nf; |
c6fda282 | 382 | f->constructor(q, arg); |
0e60d245 | 383 | add_frag_mem_limit(nf, f->qsize); |
d433673e | 384 | |
e521db9d PE |
385 | setup_timer(&q->timer, f->frag_expire, (unsigned long)q); |
386 | spin_lock_init(&q->lock); | |
387 | atomic_set(&q->refcnt, 1); | |
388 | ||
389 | return q; | |
390 | } | |
c6fda282 | 391 | |
ac18e750 | 392 | static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf, |
f926e236 NA |
393 | struct inet_frags *f, |
394 | void *arg) | |
c6fda282 PE |
395 | { |
396 | struct inet_frag_queue *q; | |
397 | ||
ac18e750 | 398 | q = inet_frag_alloc(nf, f, arg); |
51456b29 | 399 | if (!q) |
c6fda282 PE |
400 | return NULL; |
401 | ||
9a375803 | 402 | return inet_frag_intern(nf, q, f, arg); |
c6fda282 | 403 | } |
abd6523d | 404 | |
ac18e750 | 405 | struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, |
f926e236 NA |
406 | struct inet_frags *f, void *key, |
407 | unsigned int hash) | |
abd6523d | 408 | { |
19952cc4 | 409 | struct inet_frag_bucket *hb; |
abd6523d | 410 | struct inet_frag_queue *q; |
5a3da1fe | 411 | int depth = 0; |
abd6523d | 412 | |
b13d3cbf FW |
413 | if (frag_mem_limit(nf) > nf->low_thresh) |
414 | inet_frag_schedule_worker(f); | |
86e93e47 | 415 | |
fb3cfe6e | 416 | hash &= (INETFRAGS_HASHSZ - 1); |
19952cc4 JDB |
417 | hb = &f->hash[hash]; |
418 | ||
419 | spin_lock(&hb->chain_lock); | |
420 | hlist_for_each_entry(q, &hb->chain, list) { | |
ac18e750 | 421 | if (q->net == nf && f->match(q, key)) { |
abd6523d | 422 | atomic_inc(&q->refcnt); |
19952cc4 | 423 | spin_unlock(&hb->chain_lock); |
abd6523d PE |
424 | return q; |
425 | } | |
5a3da1fe | 426 | depth++; |
abd6523d | 427 | } |
19952cc4 | 428 | spin_unlock(&hb->chain_lock); |
abd6523d | 429 | |
5a3da1fe HFS |
430 | if (depth <= INETFRAGS_MAXDEPTH) |
431 | return inet_frag_create(nf, f, key); | |
e3a57d18 FW |
432 | |
433 | if (inet_frag_may_rebuild(f)) { | |
ab1c724f FW |
434 | if (!f->rebuild) |
435 | f->rebuild = true; | |
e3a57d18 FW |
436 | inet_frag_schedule_worker(f); |
437 | } | |
438 | ||
439 | return ERR_PTR(-ENOBUFS); | |
abd6523d PE |
440 | } |
441 | EXPORT_SYMBOL(inet_frag_find); | |
5a3da1fe HFS |
442 | |
443 | void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, | |
444 | const char *prefix) | |
445 | { | |
446 | static const char msg[] = "inet_frag_find: Fragment hash bucket" | |
447 | " list length grew over limit " __stringify(INETFRAGS_MAXDEPTH) | |
448 | ". Dropping fragment.\n"; | |
449 | ||
450 | if (PTR_ERR(q) == -ENOBUFS) | |
ba7a46f1 | 451 | net_dbg_ratelimited("%s%s", prefix, msg); |
5a3da1fe HFS |
452 | } |
453 | EXPORT_SYMBOL(inet_frag_maybe_warn_overflow); |