Commit | Line | Data |
---|---|---|
e48c414e ACM |
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 | * Generic TIME_WAIT sockets functions | |
7 | * | |
8 | * From code orinally in TCP | |
9 | */ | |
10 | ||
172589cc | 11 | #include <linux/kernel.h> |
e48c414e ACM |
12 | #include <net/inet_hashtables.h> |
13 | #include <net/inet_timewait_sock.h> | |
696ab2d3 | 14 | #include <net/ip.h> |
e48c414e ACM |
15 | |
16 | /* Must be called with locally disabled BHs. */ | |
acd159b6 AB |
17 | static void __inet_twsk_kill(struct inet_timewait_sock *tw, |
18 | struct inet_hashinfo *hashinfo) | |
e48c414e ACM |
19 | { |
20 | struct inet_bind_hashbucket *bhead; | |
21 | struct inet_bind_bucket *tb; | |
22 | /* Unlink from established hashes. */ | |
230140cf | 23 | rwlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash); |
e48c414e | 24 | |
230140cf | 25 | write_lock(lock); |
3ab5aee7 | 26 | if (hlist_nulls_unhashed(&tw->tw_node)) { |
230140cf | 27 | write_unlock(lock); |
e48c414e ACM |
28 | return; |
29 | } | |
3ab5aee7 ED |
30 | hlist_nulls_del_rcu(&tw->tw_node); |
31 | sk_nulls_node_init(&tw->tw_node); | |
230140cf | 32 | write_unlock(lock); |
e48c414e ACM |
33 | |
34 | /* Disassociate with bind bucket. */ | |
7f635ab7 PE |
35 | bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num, |
36 | hashinfo->bhash_size)]; | |
e48c414e ACM |
37 | spin_lock(&bhead->lock); |
38 | tb = tw->tw_tb; | |
39 | __hlist_del(&tw->tw_bind_node); | |
40 | tw->tw_tb = NULL; | |
41 | inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); | |
42 | spin_unlock(&bhead->lock); | |
43 | #ifdef SOCK_REFCNT_DEBUG | |
44 | if (atomic_read(&tw->tw_refcnt) != 1) { | |
45 | printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n", | |
46 | tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt)); | |
47 | } | |
48 | #endif | |
49 | inet_twsk_put(tw); | |
50 | } | |
51 | ||
7054fb93 PE |
52 | void inet_twsk_put(struct inet_timewait_sock *tw) |
53 | { | |
54 | if (atomic_dec_and_test(&tw->tw_refcnt)) { | |
55 | struct module *owner = tw->tw_prot->owner; | |
56 | twsk_destructor((struct sock *)tw); | |
57 | #ifdef SOCK_REFCNT_DEBUG | |
58 | printk(KERN_DEBUG "%s timewait_sock %p released\n", | |
59 | tw->tw_prot->name, tw); | |
60 | #endif | |
cd5342d9 | 61 | release_net(twsk_net(tw)); |
7054fb93 PE |
62 | kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw); |
63 | module_put(owner); | |
64 | } | |
65 | } | |
66 | EXPORT_SYMBOL_GPL(inet_twsk_put); | |
67 | ||
e48c414e ACM |
68 | /* |
69 | * Enter the time wait state. This is called with locally disabled BH. | |
70 | * Essentially we whip up a timewait bucket, copy the relevant info into it | |
71 | * from the SK, and mess with hash chains and list linkage. | |
72 | */ | |
73 | void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk, | |
74 | struct inet_hashinfo *hashinfo) | |
75 | { | |
76 | const struct inet_sock *inet = inet_sk(sk); | |
463c84b9 | 77 | const struct inet_connection_sock *icsk = inet_csk(sk); |
81c3d547 | 78 | struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash); |
230140cf | 79 | rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash); |
e48c414e ACM |
80 | struct inet_bind_hashbucket *bhead; |
81 | /* Step 1: Put TW into bind hash. Original socket stays there too. | |
82 | Note, that any socket with inet->num != 0 MUST be bound in | |
83 | binding cache, even if it is closed. | |
84 | */ | |
7f635ab7 PE |
85 | bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->num, |
86 | hashinfo->bhash_size)]; | |
e48c414e | 87 | spin_lock(&bhead->lock); |
463c84b9 | 88 | tw->tw_tb = icsk->icsk_bind_hash; |
547b792c | 89 | WARN_ON(!icsk->icsk_bind_hash); |
e48c414e ACM |
90 | inet_twsk_add_bind_node(tw, &tw->tw_tb->owners); |
91 | spin_unlock(&bhead->lock); | |
92 | ||
230140cf | 93 | write_lock(lock); |
e48c414e | 94 | |
3ab5aee7 ED |
95 | /* |
96 | * Step 2: Hash TW into TIMEWAIT chain. | |
97 | * Should be done before removing sk from established chain | |
98 | * because readers are lockless and search established first. | |
99 | */ | |
e48c414e | 100 | atomic_inc(&tw->tw_refcnt); |
3ab5aee7 ED |
101 | inet_twsk_add_node_rcu(tw, &ehead->twchain); |
102 | ||
103 | /* Step 3: Remove SK from established hash. */ | |
104 | if (__sk_nulls_del_node_init_rcu(sk)) | |
105 | sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); | |
e48c414e | 106 | |
230140cf | 107 | write_unlock(lock); |
e48c414e | 108 | } |
c676270b | 109 | |
696ab2d3 ACM |
110 | EXPORT_SYMBOL_GPL(__inet_twsk_hashdance); |
111 | ||
c676270b ACM |
112 | struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state) |
113 | { | |
6d6ee43e ACM |
114 | struct inet_timewait_sock *tw = |
115 | kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab, | |
54e6ecb2 | 116 | GFP_ATOMIC); |
c676270b ACM |
117 | if (tw != NULL) { |
118 | const struct inet_sock *inet = inet_sk(sk); | |
119 | ||
120 | /* Give us an identity. */ | |
121 | tw->tw_daddr = inet->daddr; | |
122 | tw->tw_rcv_saddr = inet->rcv_saddr; | |
123 | tw->tw_bound_dev_if = sk->sk_bound_dev_if; | |
124 | tw->tw_num = inet->num; | |
125 | tw->tw_state = TCP_TIME_WAIT; | |
126 | tw->tw_substate = state; | |
127 | tw->tw_sport = inet->sport; | |
128 | tw->tw_dport = inet->dport; | |
129 | tw->tw_family = sk->sk_family; | |
130 | tw->tw_reuse = sk->sk_reuse; | |
81c3d547 | 131 | tw->tw_hash = sk->sk_hash; |
c676270b | 132 | tw->tw_ipv6only = 0; |
f5715aea | 133 | tw->tw_transparent = inet->transparent; |
c676270b | 134 | tw->tw_prot = sk->sk_prot_creator; |
cd5342d9 | 135 | twsk_net_set(tw, hold_net(sock_net(sk))); |
c676270b ACM |
136 | atomic_set(&tw->tw_refcnt, 1); |
137 | inet_twsk_dead_node_init(tw); | |
eeb2b856 | 138 | __module_get(tw->tw_prot->owner); |
c676270b ACM |
139 | } |
140 | ||
141 | return tw; | |
142 | } | |
696ab2d3 ACM |
143 | |
144 | EXPORT_SYMBOL_GPL(inet_twsk_alloc); | |
145 | ||
146 | /* Returns non-zero if quota exceeded. */ | |
147 | static int inet_twdr_do_twkill_work(struct inet_timewait_death_row *twdr, | |
148 | const int slot) | |
149 | { | |
150 | struct inet_timewait_sock *tw; | |
151 | struct hlist_node *node; | |
152 | unsigned int killed; | |
153 | int ret; | |
154 | ||
155 | /* NOTE: compare this to previous version where lock | |
156 | * was released after detaching chain. It was racy, | |
157 | * because tw buckets are scheduled in not serialized context | |
158 | * in 2.3 (with netfilter), and with softnet it is common, because | |
159 | * soft irqs are not sequenced. | |
160 | */ | |
161 | killed = 0; | |
162 | ret = 0; | |
163 | rescan: | |
164 | inet_twsk_for_each_inmate(tw, node, &twdr->cells[slot]) { | |
165 | __inet_twsk_del_dead_node(tw); | |
166 | spin_unlock(&twdr->death_lock); | |
167 | __inet_twsk_kill(tw, twdr->hashinfo); | |
f2bf415c PE |
168 | #ifdef CONFIG_NET_NS |
169 | NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED); | |
170 | #endif | |
696ab2d3 ACM |
171 | inet_twsk_put(tw); |
172 | killed++; | |
173 | spin_lock(&twdr->death_lock); | |
174 | if (killed > INET_TWDR_TWKILL_QUOTA) { | |
175 | ret = 1; | |
176 | break; | |
177 | } | |
178 | ||
179 | /* While we dropped twdr->death_lock, another cpu may have | |
180 | * killed off the next TW bucket in the list, therefore | |
181 | * do a fresh re-read of the hlist head node with the | |
182 | * lock reacquired. We still use the hlist traversal | |
183 | * macro in order to get the prefetches. | |
184 | */ | |
185 | goto rescan; | |
186 | } | |
187 | ||
188 | twdr->tw_count -= killed; | |
f2bf415c PE |
189 | #ifndef CONFIG_NET_NS |
190 | NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITED, killed); | |
191 | #endif | |
696ab2d3 ACM |
192 | return ret; |
193 | } | |
194 | ||
195 | void inet_twdr_hangman(unsigned long data) | |
196 | { | |
197 | struct inet_timewait_death_row *twdr; | |
198 | int unsigned need_timer; | |
199 | ||
200 | twdr = (struct inet_timewait_death_row *)data; | |
201 | spin_lock(&twdr->death_lock); | |
202 | ||
203 | if (twdr->tw_count == 0) | |
204 | goto out; | |
205 | ||
206 | need_timer = 0; | |
207 | if (inet_twdr_do_twkill_work(twdr, twdr->slot)) { | |
208 | twdr->thread_slots |= (1 << twdr->slot); | |
696ab2d3 ACM |
209 | schedule_work(&twdr->twkill_work); |
210 | need_timer = 1; | |
211 | } else { | |
212 | /* We purged the entire slot, anything left? */ | |
213 | if (twdr->tw_count) | |
214 | need_timer = 1; | |
215 | } | |
216 | twdr->slot = ((twdr->slot + 1) & (INET_TWDR_TWKILL_SLOTS - 1)); | |
217 | if (need_timer) | |
218 | mod_timer(&twdr->tw_timer, jiffies + twdr->period); | |
219 | out: | |
220 | spin_unlock(&twdr->death_lock); | |
221 | } | |
222 | ||
223 | EXPORT_SYMBOL_GPL(inet_twdr_hangman); | |
224 | ||
65f27f38 | 225 | void inet_twdr_twkill_work(struct work_struct *work) |
696ab2d3 | 226 | { |
65f27f38 DH |
227 | struct inet_timewait_death_row *twdr = |
228 | container_of(work, struct inet_timewait_death_row, twkill_work); | |
696ab2d3 ACM |
229 | int i; |
230 | ||
95c9382a PE |
231 | BUILD_BUG_ON((INET_TWDR_TWKILL_SLOTS - 1) > |
232 | (sizeof(twdr->thread_slots) * 8)); | |
696ab2d3 ACM |
233 | |
234 | while (twdr->thread_slots) { | |
235 | spin_lock_bh(&twdr->death_lock); | |
236 | for (i = 0; i < INET_TWDR_TWKILL_SLOTS; i++) { | |
237 | if (!(twdr->thread_slots & (1 << i))) | |
238 | continue; | |
239 | ||
240 | while (inet_twdr_do_twkill_work(twdr, i) != 0) { | |
241 | if (need_resched()) { | |
242 | spin_unlock_bh(&twdr->death_lock); | |
243 | schedule(); | |
244 | spin_lock_bh(&twdr->death_lock); | |
245 | } | |
246 | } | |
247 | ||
248 | twdr->thread_slots &= ~(1 << i); | |
249 | } | |
250 | spin_unlock_bh(&twdr->death_lock); | |
251 | } | |
252 | } | |
253 | ||
254 | EXPORT_SYMBOL_GPL(inet_twdr_twkill_work); | |
255 | ||
256 | /* These are always called from BH context. See callers in | |
257 | * tcp_input.c to verify this. | |
258 | */ | |
259 | ||
260 | /* This is for handling early-kills of TIME_WAIT sockets. */ | |
261 | void inet_twsk_deschedule(struct inet_timewait_sock *tw, | |
262 | struct inet_timewait_death_row *twdr) | |
263 | { | |
264 | spin_lock(&twdr->death_lock); | |
265 | if (inet_twsk_del_dead_node(tw)) { | |
266 | inet_twsk_put(tw); | |
267 | if (--twdr->tw_count == 0) | |
268 | del_timer(&twdr->tw_timer); | |
269 | } | |
270 | spin_unlock(&twdr->death_lock); | |
271 | __inet_twsk_kill(tw, twdr->hashinfo); | |
272 | } | |
273 | ||
274 | EXPORT_SYMBOL(inet_twsk_deschedule); | |
275 | ||
276 | void inet_twsk_schedule(struct inet_timewait_sock *tw, | |
277 | struct inet_timewait_death_row *twdr, | |
278 | const int timeo, const int timewait_len) | |
279 | { | |
280 | struct hlist_head *list; | |
281 | int slot; | |
282 | ||
283 | /* timeout := RTO * 3.5 | |
284 | * | |
285 | * 3.5 = 1+2+0.5 to wait for two retransmits. | |
286 | * | |
287 | * RATIONALE: if FIN arrived and we entered TIME-WAIT state, | |
288 | * our ACK acking that FIN can be lost. If N subsequent retransmitted | |
289 | * FINs (or previous seqments) are lost (probability of such event | |
290 | * is p^(N+1), where p is probability to lose single packet and | |
291 | * time to detect the loss is about RTO*(2^N - 1) with exponential | |
292 | * backoff). Normal timewait length is calculated so, that we | |
293 | * waited at least for one retransmitted FIN (maximal RTO is 120sec). | |
294 | * [ BTW Linux. following BSD, violates this requirement waiting | |
295 | * only for 60sec, we should wait at least for 240 secs. | |
296 | * Well, 240 consumes too much of resources 8) | |
297 | * ] | |
298 | * This interval is not reduced to catch old duplicate and | |
299 | * responces to our wandering segments living for two MSLs. | |
300 | * However, if we use PAWS to detect | |
301 | * old duplicates, we can reduce the interval to bounds required | |
302 | * by RTO, rather than MSL. So, if peer understands PAWS, we | |
303 | * kill tw bucket after 3.5*RTO (it is important that this number | |
304 | * is greater than TS tick!) and detect old duplicates with help | |
305 | * of PAWS. | |
306 | */ | |
307 | slot = (timeo + (1 << INET_TWDR_RECYCLE_TICK) - 1) >> INET_TWDR_RECYCLE_TICK; | |
308 | ||
309 | spin_lock(&twdr->death_lock); | |
310 | ||
311 | /* Unlink it, if it was scheduled */ | |
312 | if (inet_twsk_del_dead_node(tw)) | |
313 | twdr->tw_count--; | |
314 | else | |
315 | atomic_inc(&tw->tw_refcnt); | |
316 | ||
317 | if (slot >= INET_TWDR_RECYCLE_SLOTS) { | |
318 | /* Schedule to slow timer */ | |
319 | if (timeo >= timewait_len) { | |
320 | slot = INET_TWDR_TWKILL_SLOTS - 1; | |
321 | } else { | |
172589cc | 322 | slot = DIV_ROUND_UP(timeo, twdr->period); |
696ab2d3 ACM |
323 | if (slot >= INET_TWDR_TWKILL_SLOTS) |
324 | slot = INET_TWDR_TWKILL_SLOTS - 1; | |
325 | } | |
326 | tw->tw_ttd = jiffies + timeo; | |
327 | slot = (twdr->slot + slot) & (INET_TWDR_TWKILL_SLOTS - 1); | |
328 | list = &twdr->cells[slot]; | |
329 | } else { | |
330 | tw->tw_ttd = jiffies + (slot << INET_TWDR_RECYCLE_TICK); | |
331 | ||
332 | if (twdr->twcal_hand < 0) { | |
333 | twdr->twcal_hand = 0; | |
334 | twdr->twcal_jiffie = jiffies; | |
335 | twdr->twcal_timer.expires = twdr->twcal_jiffie + | |
336 | (slot << INET_TWDR_RECYCLE_TICK); | |
337 | add_timer(&twdr->twcal_timer); | |
338 | } else { | |
339 | if (time_after(twdr->twcal_timer.expires, | |
340 | jiffies + (slot << INET_TWDR_RECYCLE_TICK))) | |
341 | mod_timer(&twdr->twcal_timer, | |
342 | jiffies + (slot << INET_TWDR_RECYCLE_TICK)); | |
343 | slot = (twdr->twcal_hand + slot) & (INET_TWDR_RECYCLE_SLOTS - 1); | |
344 | } | |
345 | list = &twdr->twcal_row[slot]; | |
346 | } | |
347 | ||
348 | hlist_add_head(&tw->tw_death_node, list); | |
349 | ||
350 | if (twdr->tw_count++ == 0) | |
351 | mod_timer(&twdr->tw_timer, jiffies + twdr->period); | |
352 | spin_unlock(&twdr->death_lock); | |
353 | } | |
354 | ||
355 | EXPORT_SYMBOL_GPL(inet_twsk_schedule); | |
356 | ||
357 | void inet_twdr_twcal_tick(unsigned long data) | |
358 | { | |
359 | struct inet_timewait_death_row *twdr; | |
360 | int n, slot; | |
361 | unsigned long j; | |
362 | unsigned long now = jiffies; | |
363 | int killed = 0; | |
364 | int adv = 0; | |
365 | ||
366 | twdr = (struct inet_timewait_death_row *)data; | |
367 | ||
368 | spin_lock(&twdr->death_lock); | |
369 | if (twdr->twcal_hand < 0) | |
370 | goto out; | |
371 | ||
372 | slot = twdr->twcal_hand; | |
373 | j = twdr->twcal_jiffie; | |
374 | ||
375 | for (n = 0; n < INET_TWDR_RECYCLE_SLOTS; n++) { | |
376 | if (time_before_eq(j, now)) { | |
377 | struct hlist_node *node, *safe; | |
378 | struct inet_timewait_sock *tw; | |
379 | ||
380 | inet_twsk_for_each_inmate_safe(tw, node, safe, | |
381 | &twdr->twcal_row[slot]) { | |
382 | __inet_twsk_del_dead_node(tw); | |
383 | __inet_twsk_kill(tw, twdr->hashinfo); | |
f2bf415c PE |
384 | #ifdef CONFIG_NET_NS |
385 | NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED); | |
386 | #endif | |
696ab2d3 ACM |
387 | inet_twsk_put(tw); |
388 | killed++; | |
389 | } | |
390 | } else { | |
391 | if (!adv) { | |
392 | adv = 1; | |
393 | twdr->twcal_jiffie = j; | |
394 | twdr->twcal_hand = slot; | |
395 | } | |
396 | ||
397 | if (!hlist_empty(&twdr->twcal_row[slot])) { | |
398 | mod_timer(&twdr->twcal_timer, j); | |
399 | goto out; | |
400 | } | |
401 | } | |
402 | j += 1 << INET_TWDR_RECYCLE_TICK; | |
403 | slot = (slot + 1) & (INET_TWDR_RECYCLE_SLOTS - 1); | |
404 | } | |
405 | twdr->twcal_hand = -1; | |
406 | ||
407 | out: | |
408 | if ((twdr->tw_count -= killed) == 0) | |
409 | del_timer(&twdr->tw_timer); | |
f2bf415c PE |
410 | #ifndef CONFIG_NET_NS |
411 | NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITKILLED, killed); | |
412 | #endif | |
696ab2d3 ACM |
413 | spin_unlock(&twdr->death_lock); |
414 | } | |
415 | ||
416 | EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick); | |
d315492b DL |
417 | |
418 | void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo, | |
419 | struct inet_timewait_death_row *twdr, int family) | |
420 | { | |
421 | struct inet_timewait_sock *tw; | |
422 | struct sock *sk; | |
3ab5aee7 | 423 | struct hlist_nulls_node *node; |
d315492b DL |
424 | int h; |
425 | ||
426 | local_bh_disable(); | |
427 | for (h = 0; h < (hashinfo->ehash_size); h++) { | |
428 | struct inet_ehash_bucket *head = | |
429 | inet_ehash_bucket(hashinfo, h); | |
430 | rwlock_t *lock = inet_ehash_lockp(hashinfo, h); | |
431 | restart: | |
432 | write_lock(lock); | |
3ab5aee7 | 433 | sk_nulls_for_each(sk, node, &head->twchain) { |
d315492b DL |
434 | |
435 | tw = inet_twsk(sk); | |
436 | if (!net_eq(twsk_net(tw), net) || | |
437 | tw->tw_family != family) | |
438 | continue; | |
439 | ||
440 | atomic_inc(&tw->tw_refcnt); | |
441 | write_unlock(lock); | |
442 | inet_twsk_deschedule(tw, twdr); | |
443 | inet_twsk_put(tw); | |
444 | ||
445 | goto restart; | |
446 | } | |
447 | write_unlock(lock); | |
448 | } | |
449 | local_bh_enable(); | |
450 | } | |
451 | EXPORT_SYMBOL_GPL(inet_twsk_purge); |