Blame view

net/ipv4/inet_timewait_sock.c 14.4 KB
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
1
2
3
4
5
6
7
8
9
  /*
   * INET		An implementation of the TCP/IP protocol suite for the LINUX
   *		operating system.  INET is implemented using the  BSD Socket
   *		interface as the means of communication with the user level.
   *
   *		Generic TIME_WAIT sockets functions
   *
   *		From code orinally in TCP
   */
172589ccd   Ilpo Järvinen   [NET]: DIV_ROUND_...
10
  #include <linux/kernel.h>
9e337b0fb   Vegard Nossum   net: annotate ine...
11
  #include <linux/kmemcheck.h>
5a0e3ad6a   Tejun Heo   include cleanup: ...
12
  #include <linux/slab.h>
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
13
14
  #include <net/inet_hashtables.h>
  #include <net/inet_timewait_sock.h>
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
15
  #include <net/ip.h>
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
16

13475a30b   Eric Dumazet   tcp: connect() ra...
17

2a8875e73   Eric Dumazet   [PATCH] tcp: docu...
18
19
20
21
22
23
24
  /**
   *	inet_twsk_unhash - unhash a timewait socket from established hash
   *	@tw: timewait socket
   *
   *	unhash a timewait socket from established hash, if hashed.
   *	ehash lock must be held by caller.
   *	Returns 1 if caller should call inet_twsk_put() after lock release.
13475a30b   Eric Dumazet   tcp: connect() ra...
25
26
27
28
29
30
31
32
   */
  int inet_twsk_unhash(struct inet_timewait_sock *tw)
  {
  	if (hlist_nulls_unhashed(&tw->tw_node))
  		return 0;
  
  	hlist_nulls_del_rcu(&tw->tw_node);
  	sk_nulls_node_init(&tw->tw_node);
2a8875e73   Eric Dumazet   [PATCH] tcp: docu...
33
34
35
36
  	/*
  	 * We cannot call inet_twsk_put() ourself under lock,
  	 * caller must call it for us.
  	 */
13475a30b   Eric Dumazet   tcp: connect() ra...
37
38
  	return 1;
  }
2a8875e73   Eric Dumazet   [PATCH] tcp: docu...
39
40
41
42
43
44
45
46
  /**
   *	inet_twsk_bind_unhash - unhash a timewait socket from bind hash
   *	@tw: timewait socket
   *	@hashinfo: hashinfo pointer
   *
   *	unhash a timewait socket from bind hash, if hashed.
   *	bind hash lock must be held by caller.
   *	Returns 1 if caller should call inet_twsk_put() after lock release.
3cdaedae6   Eric Dumazet   tcp: Fix a connec...
47
48
49
50
51
52
53
54
55
56
57
58
   */
  int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
  			  struct inet_hashinfo *hashinfo)
  {
  	struct inet_bind_bucket *tb = tw->tw_tb;
  
  	if (!tb)
  		return 0;
  
  	__hlist_del(&tw->tw_bind_node);
  	tw->tw_tb = NULL;
  	inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
2a8875e73   Eric Dumazet   [PATCH] tcp: docu...
59
60
61
62
  	/*
  	 * We cannot call inet_twsk_put() ourself under lock,
  	 * caller must call it for us.
  	 */
3cdaedae6   Eric Dumazet   tcp: Fix a connec...
63
64
  	return 1;
  }
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
65
  /* Must be called with locally disabled BHs. */
acd159b6b   Adrian Bunk   [INET_SOCK]: make...
66
67
  static void __inet_twsk_kill(struct inet_timewait_sock *tw,
  			     struct inet_hashinfo *hashinfo)
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
68
69
  {
  	struct inet_bind_hashbucket *bhead;
13475a30b   Eric Dumazet   tcp: connect() ra...
70
  	int refcnt;
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
71
  	/* Unlink from established hashes. */
9db66bdcc   Eric Dumazet   net: convert TCP/...
72
  	spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
73

9db66bdcc   Eric Dumazet   net: convert TCP/...
74
  	spin_lock(lock);
13475a30b   Eric Dumazet   tcp: connect() ra...
75
  	refcnt = inet_twsk_unhash(tw);
9db66bdcc   Eric Dumazet   net: convert TCP/...
76
  	spin_unlock(lock);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
77
78
  
  	/* Disassociate with bind bucket. */
7f635ab71   Pavel Emelyanov   inet: add struct ...
79
80
  	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
  			hashinfo->bhash_size)];
3cdaedae6   Eric Dumazet   tcp: Fix a connec...
81

e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
82
  	spin_lock(&bhead->lock);
3cdaedae6   Eric Dumazet   tcp: Fix a connec...
83
  	refcnt += inet_twsk_bind_unhash(tw, hashinfo);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
84
  	spin_unlock(&bhead->lock);
3cdaedae6   Eric Dumazet   tcp: Fix a connec...
85

e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
86
87
88
89
90
91
92
  #ifdef SOCK_REFCNT_DEBUG
  	if (atomic_read(&tw->tw_refcnt) != 1) {
  		printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d
  ",
  		       tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
  	}
  #endif
13475a30b   Eric Dumazet   tcp: connect() ra...
93
94
95
96
  	while (refcnt) {
  		inet_twsk_put(tw);
  		refcnt--;
  	}
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
97
  }
4dbc8ef7e   Arnaldo Carvalho de Melo   net: Make inet_tw...
98
  static noinline void inet_twsk_free(struct inet_timewait_sock *tw)
7054fb937   Pavel Emelyanov   [INET]: Uninline ...
99
  {
4dbc8ef7e   Arnaldo Carvalho de Melo   net: Make inet_tw...
100
101
  	struct module *owner = tw->tw_prot->owner;
  	twsk_destructor((struct sock *)tw);
7054fb937   Pavel Emelyanov   [INET]: Uninline ...
102
  #ifdef SOCK_REFCNT_DEBUG
4dbc8ef7e   Arnaldo Carvalho de Melo   net: Make inet_tw...
103
104
  	pr_debug("%s timewait_sock %p released
  ", tw->tw_prot->name, tw);
7054fb937   Pavel Emelyanov   [INET]: Uninline ...
105
  #endif
4dbc8ef7e   Arnaldo Carvalho de Melo   net: Make inet_tw...
106
107
108
109
110
111
112
113
114
  	release_net(twsk_net(tw));
  	kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);
  	module_put(owner);
  }
  
  void inet_twsk_put(struct inet_timewait_sock *tw)
  {
  	if (atomic_dec_and_test(&tw->tw_refcnt))
  		inet_twsk_free(tw);
7054fb937   Pavel Emelyanov   [INET]: Uninline ...
115
116
  }
  EXPORT_SYMBOL_GPL(inet_twsk_put);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
117
118
119
120
121
122
123
124
125
  /*
   * Enter the time wait state. This is called with locally disabled BH.
   * Essentially we whip up a timewait bucket, copy the relevant info into it
   * from the SK, and mess with hash chains and list linkage.
   */
  void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
  			   struct inet_hashinfo *hashinfo)
  {
  	const struct inet_sock *inet = inet_sk(sk);
463c84b97   Arnaldo Carvalho de Melo   [NET]: Introduce ...
126
  	const struct inet_connection_sock *icsk = inet_csk(sk);
81c3d5470   Eric Dumazet   [INET]: speedup i...
127
  	struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);
9db66bdcc   Eric Dumazet   net: convert TCP/...
128
  	spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
129
130
131
132
133
  	struct inet_bind_hashbucket *bhead;
  	/* Step 1: Put TW into bind hash. Original socket stays there too.
  	   Note, that any socket with inet->num != 0 MUST be bound in
  	   binding cache, even if it is closed.
  	 */
c720c7e83   Eric Dumazet   inet: rename some...
134
  	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
7f635ab71   Pavel Emelyanov   inet: add struct ...
135
  			hashinfo->bhash_size)];
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
136
  	spin_lock(&bhead->lock);
463c84b97   Arnaldo Carvalho de Melo   [NET]: Introduce ...
137
  	tw->tw_tb = icsk->icsk_bind_hash;
547b792ca   Ilpo Järvinen   net: convert BUG_...
138
  	WARN_ON(!icsk->icsk_bind_hash);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
139
140
  	inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
  	spin_unlock(&bhead->lock);
9db66bdcc   Eric Dumazet   net: convert TCP/...
141
  	spin_lock(lock);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
142

3ab5aee7f   Eric Dumazet   net: Convert TCP ...
143
144
145
146
147
  	/*
  	 * Step 2: Hash TW into TIMEWAIT chain.
  	 * Should be done before removing sk from established chain
  	 * because readers are lockless and search established first.
  	 */
3ab5aee7f   Eric Dumazet   net: Convert TCP ...
148
149
150
151
152
  	inet_twsk_add_node_rcu(tw, &ehead->twchain);
  
  	/* Step 3: Remove SK from established hash. */
  	if (__sk_nulls_del_node_init_rcu(sk))
  		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
153

47e1c3230   Eric Dumazet   tcp: fix a timewa...
154
155
  	/*
  	 * Notes :
2a8875e73   Eric Dumazet   [PATCH] tcp: docu...
156
  	 * - We initially set tw_refcnt to 0 in inet_twsk_alloc()
47e1c3230   Eric Dumazet   tcp: fix a timewa...
157
158
159
160
161
162
  	 * - We add one reference for the bhash link
  	 * - We add one reference for the ehash link
  	 * - We want this refcnt update done before allowing other
  	 *   threads to find this tw in ehash chain.
  	 */
  	atomic_add(1 + 1 + 1, &tw->tw_refcnt);
9db66bdcc   Eric Dumazet   net: convert TCP/...
163
  	spin_unlock(lock);
e48c414ee   Arnaldo Carvalho de Melo   [INET]: Generalis...
164
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
165
  EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
166
167
  struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state)
  {
6d6ee43e0   Arnaldo Carvalho de Melo   [TWSK]: Introduce...
168
169
  	struct inet_timewait_sock *tw =
  		kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab,
54e6ecb23   Christoph Lameter   [PATCH] slab: rem...
170
  				 GFP_ATOMIC);
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
171
172
  	if (tw != NULL) {
  		const struct inet_sock *inet = inet_sk(sk);
9e337b0fb   Vegard Nossum   net: annotate ine...
173
  		kmemcheck_annotate_bitfield(tw, flags);
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
174
  		/* Give us an identity. */
c720c7e83   Eric Dumazet   inet: rename some...
175
176
  		tw->tw_daddr	    = inet->inet_daddr;
  		tw->tw_rcv_saddr    = inet->inet_rcv_saddr;
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
177
  		tw->tw_bound_dev_if = sk->sk_bound_dev_if;
c720c7e83   Eric Dumazet   inet: rename some...
178
  		tw->tw_num	    = inet->inet_num;
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
179
180
  		tw->tw_state	    = TCP_TIME_WAIT;
  		tw->tw_substate	    = state;
c720c7e83   Eric Dumazet   inet: rename some...
181
182
  		tw->tw_sport	    = inet->inet_sport;
  		tw->tw_dport	    = inet->inet_dport;
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
183
184
  		tw->tw_family	    = sk->sk_family;
  		tw->tw_reuse	    = sk->sk_reuse;
81c3d5470   Eric Dumazet   [INET]: speedup i...
185
  		tw->tw_hash	    = sk->sk_hash;
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
186
  		tw->tw_ipv6only	    = 0;
f5715aea4   KOVACS Krisztian   ipv4: Implement I...
187
  		tw->tw_transparent  = inet->transparent;
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
188
  		tw->tw_prot	    = sk->sk_prot_creator;
cd5342d90   Denis V. Lunev   [NETNS]: Add netn...
189
  		twsk_net_set(tw, hold_net(sock_net(sk)));
47e1c3230   Eric Dumazet   tcp: fix a timewa...
190
191
192
193
194
195
  		/*
  		 * Because we use RCU lookups, we should not set tw_refcnt
  		 * to a non null value before everything is setup for this
  		 * timewait socket.
  		 */
  		atomic_set(&tw->tw_refcnt, 0);
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
196
  		inet_twsk_dead_node_init(tw);
eeb2b8560   Arnaldo Carvalho de Melo   [TWSK]: Grab the ...
197
  		__module_get(tw->tw_prot->owner);
c676270bc   Arnaldo Carvalho de Melo   [INET_TWSK]: Intr...
198
199
200
201
  	}
  
  	return tw;
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
  EXPORT_SYMBOL_GPL(inet_twsk_alloc);
  
  /* Returns non-zero if quota exceeded.  */
  static int inet_twdr_do_twkill_work(struct inet_timewait_death_row *twdr,
  				    const int slot)
  {
  	struct inet_timewait_sock *tw;
  	struct hlist_node *node;
  	unsigned int killed;
  	int ret;
  
  	/* NOTE: compare this to previous version where lock
  	 * was released after detaching chain. It was racy,
  	 * because tw buckets are scheduled in not serialized context
  	 * in 2.3 (with netfilter), and with softnet it is common, because
  	 * soft irqs are not sequenced.
  	 */
  	killed = 0;
  	ret = 0;
  rescan:
  	inet_twsk_for_each_inmate(tw, node, &twdr->cells[slot]) {
  		__inet_twsk_del_dead_node(tw);
  		spin_unlock(&twdr->death_lock);
  		__inet_twsk_kill(tw, twdr->hashinfo);
f2bf415cf   Pavel Emelyanov   mib: add net to N...
226
227
228
  #ifdef CONFIG_NET_NS
  		NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED);
  #endif
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
  		inet_twsk_put(tw);
  		killed++;
  		spin_lock(&twdr->death_lock);
  		if (killed > INET_TWDR_TWKILL_QUOTA) {
  			ret = 1;
  			break;
  		}
  
  		/* While we dropped twdr->death_lock, another cpu may have
  		 * killed off the next TW bucket in the list, therefore
  		 * do a fresh re-read of the hlist head node with the
  		 * lock reacquired.  We still use the hlist traversal
  		 * macro in order to get the prefetches.
  		 */
  		goto rescan;
  	}
  
  	twdr->tw_count -= killed;
f2bf415cf   Pavel Emelyanov   mib: add net to N...
247
248
249
  #ifndef CONFIG_NET_NS
  	NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITED, killed);
  #endif
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
  	return ret;
  }
  
  void inet_twdr_hangman(unsigned long data)
  {
  	struct inet_timewait_death_row *twdr;
  	int unsigned need_timer;
  
  	twdr = (struct inet_timewait_death_row *)data;
  	spin_lock(&twdr->death_lock);
  
  	if (twdr->tw_count == 0)
  		goto out;
  
  	need_timer = 0;
  	if (inet_twdr_do_twkill_work(twdr, twdr->slot)) {
  		twdr->thread_slots |= (1 << twdr->slot);
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
267
268
269
270
271
272
  		schedule_work(&twdr->twkill_work);
  		need_timer = 1;
  	} else {
  		/* We purged the entire slot, anything left?  */
  		if (twdr->tw_count)
  			need_timer = 1;
80a1096ba   Octavian Purdila   tcp: fix prematur...
273
  		twdr->slot = ((twdr->slot + 1) & (INET_TWDR_TWKILL_SLOTS - 1));
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
274
  	}
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
275
276
277
278
279
  	if (need_timer)
  		mod_timer(&twdr->tw_timer, jiffies + twdr->period);
  out:
  	spin_unlock(&twdr->death_lock);
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
280
  EXPORT_SYMBOL_GPL(inet_twdr_hangman);
65f27f384   David Howells   WorkStruct: Pass ...
281
  void inet_twdr_twkill_work(struct work_struct *work)
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
282
  {
65f27f384   David Howells   WorkStruct: Pass ...
283
284
  	struct inet_timewait_death_row *twdr =
  		container_of(work, struct inet_timewait_death_row, twkill_work);
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
285
  	int i;
95c9382a3   Pavel Emelyanov   [INET]: Use BUILD...
286
287
  	BUILD_BUG_ON((INET_TWDR_TWKILL_SLOTS - 1) >
  			(sizeof(twdr->thread_slots) * 8));
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
  
  	while (twdr->thread_slots) {
  		spin_lock_bh(&twdr->death_lock);
  		for (i = 0; i < INET_TWDR_TWKILL_SLOTS; i++) {
  			if (!(twdr->thread_slots & (1 << i)))
  				continue;
  
  			while (inet_twdr_do_twkill_work(twdr, i) != 0) {
  				if (need_resched()) {
  					spin_unlock_bh(&twdr->death_lock);
  					schedule();
  					spin_lock_bh(&twdr->death_lock);
  				}
  			}
  
  			twdr->thread_slots &= ~(1 << i);
  		}
  		spin_unlock_bh(&twdr->death_lock);
  	}
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
  EXPORT_SYMBOL_GPL(inet_twdr_twkill_work);
  
  /* These are always called from BH context.  See callers in
   * tcp_input.c to verify this.
   */
  
  /* This is for handling early-kills of TIME_WAIT sockets. */
  void inet_twsk_deschedule(struct inet_timewait_sock *tw,
  			  struct inet_timewait_death_row *twdr)
  {
  	spin_lock(&twdr->death_lock);
  	if (inet_twsk_del_dead_node(tw)) {
  		inet_twsk_put(tw);
  		if (--twdr->tw_count == 0)
  			del_timer(&twdr->tw_timer);
  	}
  	spin_unlock(&twdr->death_lock);
  	__inet_twsk_kill(tw, twdr->hashinfo);
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
  EXPORT_SYMBOL(inet_twsk_deschedule);
  
  void inet_twsk_schedule(struct inet_timewait_sock *tw,
  		       struct inet_timewait_death_row *twdr,
  		       const int timeo, const int timewait_len)
  {
  	struct hlist_head *list;
  	int slot;
  
  	/* timeout := RTO * 3.5
  	 *
  	 * 3.5 = 1+2+0.5 to wait for two retransmits.
  	 *
  	 * RATIONALE: if FIN arrived and we entered TIME-WAIT state,
  	 * our ACK acking that FIN can be lost. If N subsequent retransmitted
  	 * FINs (or previous seqments) are lost (probability of such event
  	 * is p^(N+1), where p is probability to lose single packet and
  	 * time to detect the loss is about RTO*(2^N - 1) with exponential
  	 * backoff). Normal timewait length is calculated so, that we
  	 * waited at least for one retransmitted FIN (maximal RTO is 120sec).
  	 * [ BTW Linux. following BSD, violates this requirement waiting
  	 *   only for 60sec, we should wait at least for 240 secs.
  	 *   Well, 240 consumes too much of resources 8)
  	 * ]
  	 * This interval is not reduced to catch old duplicate and
  	 * responces to our wandering segments living for two MSLs.
  	 * However, if we use PAWS to detect
  	 * old duplicates, we can reduce the interval to bounds required
  	 * by RTO, rather than MSL. So, if peer understands PAWS, we
  	 * kill tw bucket after 3.5*RTO (it is important that this number
  	 * is greater than TS tick!) and detect old duplicates with help
  	 * of PAWS.
  	 */
  	slot = (timeo + (1 << INET_TWDR_RECYCLE_TICK) - 1) >> INET_TWDR_RECYCLE_TICK;
  
  	spin_lock(&twdr->death_lock);
  
  	/* Unlink it, if it was scheduled */
  	if (inet_twsk_del_dead_node(tw))
  		twdr->tw_count--;
  	else
  		atomic_inc(&tw->tw_refcnt);
  
  	if (slot >= INET_TWDR_RECYCLE_SLOTS) {
  		/* Schedule to slow timer */
  		if (timeo >= timewait_len) {
  			slot = INET_TWDR_TWKILL_SLOTS - 1;
  		} else {
172589ccd   Ilpo Järvinen   [NET]: DIV_ROUND_...
375
  			slot = DIV_ROUND_UP(timeo, twdr->period);
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
  			if (slot >= INET_TWDR_TWKILL_SLOTS)
  				slot = INET_TWDR_TWKILL_SLOTS - 1;
  		}
  		tw->tw_ttd = jiffies + timeo;
  		slot = (twdr->slot + slot) & (INET_TWDR_TWKILL_SLOTS - 1);
  		list = &twdr->cells[slot];
  	} else {
  		tw->tw_ttd = jiffies + (slot << INET_TWDR_RECYCLE_TICK);
  
  		if (twdr->twcal_hand < 0) {
  			twdr->twcal_hand = 0;
  			twdr->twcal_jiffie = jiffies;
  			twdr->twcal_timer.expires = twdr->twcal_jiffie +
  					      (slot << INET_TWDR_RECYCLE_TICK);
  			add_timer(&twdr->twcal_timer);
  		} else {
  			if (time_after(twdr->twcal_timer.expires,
  				       jiffies + (slot << INET_TWDR_RECYCLE_TICK)))
  				mod_timer(&twdr->twcal_timer,
  					  jiffies + (slot << INET_TWDR_RECYCLE_TICK));
  			slot = (twdr->twcal_hand + slot) & (INET_TWDR_RECYCLE_SLOTS - 1);
  		}
  		list = &twdr->twcal_row[slot];
  	}
  
  	hlist_add_head(&tw->tw_death_node, list);
  
  	if (twdr->tw_count++ == 0)
  		mod_timer(&twdr->tw_timer, jiffies + twdr->period);
  	spin_unlock(&twdr->death_lock);
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
  EXPORT_SYMBOL_GPL(inet_twsk_schedule);
  
  void inet_twdr_twcal_tick(unsigned long data)
  {
  	struct inet_timewait_death_row *twdr;
  	int n, slot;
  	unsigned long j;
  	unsigned long now = jiffies;
  	int killed = 0;
  	int adv = 0;
  
  	twdr = (struct inet_timewait_death_row *)data;
  
  	spin_lock(&twdr->death_lock);
  	if (twdr->twcal_hand < 0)
  		goto out;
  
  	slot = twdr->twcal_hand;
  	j = twdr->twcal_jiffie;
  
  	for (n = 0; n < INET_TWDR_RECYCLE_SLOTS; n++) {
  		if (time_before_eq(j, now)) {
  			struct hlist_node *node, *safe;
  			struct inet_timewait_sock *tw;
  
  			inet_twsk_for_each_inmate_safe(tw, node, safe,
  						       &twdr->twcal_row[slot]) {
  				__inet_twsk_del_dead_node(tw);
  				__inet_twsk_kill(tw, twdr->hashinfo);
f2bf415cf   Pavel Emelyanov   mib: add net to N...
436
437
438
  #ifdef CONFIG_NET_NS
  				NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED);
  #endif
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
  				inet_twsk_put(tw);
  				killed++;
  			}
  		} else {
  			if (!adv) {
  				adv = 1;
  				twdr->twcal_jiffie = j;
  				twdr->twcal_hand = slot;
  			}
  
  			if (!hlist_empty(&twdr->twcal_row[slot])) {
  				mod_timer(&twdr->twcal_timer, j);
  				goto out;
  			}
  		}
  		j += 1 << INET_TWDR_RECYCLE_TICK;
  		slot = (slot + 1) & (INET_TWDR_RECYCLE_SLOTS - 1);
  	}
  	twdr->twcal_hand = -1;
  
  out:
  	if ((twdr->tw_count -= killed) == 0)
  		del_timer(&twdr->tw_timer);
f2bf415cf   Pavel Emelyanov   mib: add net to N...
462
463
464
  #ifndef CONFIG_NET_NS
  	NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITKILLED, killed);
  #endif
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
465
466
  	spin_unlock(&twdr->death_lock);
  }
696ab2d3b   Arnaldo Carvalho de Melo   [TIMEWAIT]: Move ...
467
  EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);
d315492b1   Daniel Lezcano   netns : fix kerne...
468

b099ce260   Eric W. Biederman   net: Batch inet_t...
469
  void inet_twsk_purge(struct inet_hashinfo *hashinfo,
d315492b1   Daniel Lezcano   netns : fix kerne...
470
471
472
473
  		     struct inet_timewait_death_row *twdr, int family)
  {
  	struct inet_timewait_sock *tw;
  	struct sock *sk;
3ab5aee7f   Eric Dumazet   net: Convert TCP ...
474
  	struct hlist_nulls_node *node;
575f4cd5a   Eric W. Biederman   net: Use rcu look...
475
  	unsigned int slot;
d315492b1   Daniel Lezcano   netns : fix kerne...
476

575f4cd5a   Eric W. Biederman   net: Use rcu look...
477
478
479
480
  	for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
  		struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
  restart_rcu:
  		rcu_read_lock();
d315492b1   Daniel Lezcano   netns : fix kerne...
481
  restart:
575f4cd5a   Eric W. Biederman   net: Use rcu look...
482
  		sk_nulls_for_each_rcu(sk, node, &head->twchain) {
d315492b1   Daniel Lezcano   netns : fix kerne...
483
  			tw = inet_twsk(sk);
b099ce260   Eric W. Biederman   net: Batch inet_t...
484
485
  			if ((tw->tw_family != family) ||
  				atomic_read(&twsk_net(tw)->count))
d315492b1   Daniel Lezcano   netns : fix kerne...
486
  				continue;
575f4cd5a   Eric W. Biederman   net: Use rcu look...
487
488
  			if (unlikely(!atomic_inc_not_zero(&tw->tw_refcnt)))
  				continue;
b099ce260   Eric W. Biederman   net: Batch inet_t...
489
490
  			if (unlikely((tw->tw_family != family) ||
  				     atomic_read(&twsk_net(tw)->count))) {
575f4cd5a   Eric W. Biederman   net: Use rcu look...
491
492
493
494
495
  				inet_twsk_put(tw);
  				goto restart;
  			}
  
  			rcu_read_unlock();
d315492b1   Daniel Lezcano   netns : fix kerne...
496
497
  			inet_twsk_deschedule(tw, twdr);
  			inet_twsk_put(tw);
575f4cd5a   Eric W. Biederman   net: Use rcu look...
498
  			goto restart_rcu;
d315492b1   Daniel Lezcano   netns : fix kerne...
499
  		}
575f4cd5a   Eric W. Biederman   net: Use rcu look...
500
501
502
503
504
505
506
  		/* If the nulls value we got at the end of this lookup is
  		 * not the expected one, we must restart lookup.
  		 * We probably met an item that was moved to another chain.
  		 */
  		if (get_nulls_value(node) != slot)
  			goto restart;
  		rcu_read_unlock();
d315492b1   Daniel Lezcano   netns : fix kerne...
507
  	}
d315492b1   Daniel Lezcano   netns : fix kerne...
508
509
  }
  EXPORT_SYMBOL_GPL(inet_twsk_purge);