ACPI: C-States: accounting of sleep states
[linux-2.6/mini2440.git] / net / ipv4 / inet_hashtables.c
blobee9b5515b9aea20fb28d61be5aedc04321f20676
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.
6 * Generic INET transport hashtables
8 * Authors: Lotsa people, from code originally in tcp
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 #include <linux/config.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/wait.h>
23 #include <net/inet_connection_sock.h>
24 #include <net/inet_hashtables.h>
25 #include <net/ip.h>
28 * Allocate and initialize a new local port bind bucket.
29 * The bindhash mutex for snum's hash chain must be held here.
31 struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep,
32 struct inet_bind_hashbucket *head,
33 const unsigned short snum)
35 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC);
37 if (tb != NULL) {
38 tb->port = snum;
39 tb->fastreuse = 0;
40 INIT_HLIST_HEAD(&tb->owners);
41 hlist_add_head(&tb->node, &head->chain);
43 return tb;
47 * Caller must hold hashbucket lock for this tb with local BH disabled
49 void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb)
51 if (hlist_empty(&tb->owners)) {
52 __hlist_del(&tb->node);
53 kmem_cache_free(cachep, tb);
57 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
58 const unsigned short snum)
60 inet_sk(sk)->num = snum;
61 sk_add_bind_node(sk, &tb->owners);
62 inet_csk(sk)->icsk_bind_hash = tb;
66 * Get rid of any references to a local port held by the given sock.
68 static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
70 const int bhash = inet_bhashfn(inet_sk(sk)->num, hashinfo->bhash_size);
71 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
72 struct inet_bind_bucket *tb;
74 spin_lock(&head->lock);
75 tb = inet_csk(sk)->icsk_bind_hash;
76 __sk_del_bind_node(sk);
77 inet_csk(sk)->icsk_bind_hash = NULL;
78 inet_sk(sk)->num = 0;
79 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
80 spin_unlock(&head->lock);
83 void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
85 local_bh_disable();
86 __inet_put_port(hashinfo, sk);
87 local_bh_enable();
90 EXPORT_SYMBOL(inet_put_port);
93 * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
94 * Look, when several writers sleep and reader wakes them up, all but one
95 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
96 * this, _but_ remember, it adds useless work on UP machines (wake up each
97 * exclusive lock release). It should be ifdefed really.
99 void inet_listen_wlock(struct inet_hashinfo *hashinfo)
101 write_lock(&hashinfo->lhash_lock);
103 if (atomic_read(&hashinfo->lhash_users)) {
104 DEFINE_WAIT(wait);
106 for (;;) {
107 prepare_to_wait_exclusive(&hashinfo->lhash_wait,
108 &wait, TASK_UNINTERRUPTIBLE);
109 if (!atomic_read(&hashinfo->lhash_users))
110 break;
111 write_unlock_bh(&hashinfo->lhash_lock);
112 schedule();
113 write_lock_bh(&hashinfo->lhash_lock);
116 finish_wait(&hashinfo->lhash_wait, &wait);
120 EXPORT_SYMBOL(inet_listen_wlock);
123 * Don't inline this cruft. Here are some nice properties to exploit here. The
124 * BSD API does not allow a listening sock to specify the remote port nor the
125 * remote address for the connection. So always assume those are both
126 * wildcarded during the search since they can never be otherwise.
128 struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr,
129 const unsigned short hnum, const int dif)
131 struct sock *result = NULL, *sk;
132 const struct hlist_node *node;
133 int hiscore = -1;
135 sk_for_each(sk, node, head) {
136 const struct inet_sock *inet = inet_sk(sk);
138 if (inet->num == hnum && !ipv6_only_sock(sk)) {
139 const __u32 rcv_saddr = inet->rcv_saddr;
140 int score = sk->sk_family == PF_INET ? 1 : 0;
142 if (rcv_saddr) {
143 if (rcv_saddr != daddr)
144 continue;
145 score += 2;
147 if (sk->sk_bound_dev_if) {
148 if (sk->sk_bound_dev_if != dif)
149 continue;
150 score += 2;
152 if (score == 5)
153 return sk;
154 if (score > hiscore) {
155 hiscore = score;
156 result = sk;
160 return result;
163 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
165 /* called with local bh disabled */
166 static int __inet_check_established(struct inet_timewait_death_row *death_row,
167 struct sock *sk, __u16 lport,
168 struct inet_timewait_sock **twp)
170 struct inet_hashinfo *hinfo = death_row->hashinfo;
171 struct inet_sock *inet = inet_sk(sk);
172 u32 daddr = inet->rcv_saddr;
173 u32 saddr = inet->daddr;
174 int dif = sk->sk_bound_dev_if;
175 INET_ADDR_COOKIE(acookie, saddr, daddr)
176 const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
177 unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport);
178 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
179 struct sock *sk2;
180 const struct hlist_node *node;
181 struct inet_timewait_sock *tw;
183 prefetch(head->chain.first);
184 write_lock(&head->lock);
186 /* Check TIME-WAIT sockets first. */
187 sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
188 tw = inet_twsk(sk2);
190 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) {
191 if (twsk_unique(sk, sk2, twp))
192 goto unique;
193 else
194 goto not_unique;
197 tw = NULL;
199 /* And established part... */
200 sk_for_each(sk2, node, &head->chain) {
201 if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif))
202 goto not_unique;
205 unique:
206 /* Must record num and sport now. Otherwise we will see
207 * in hash table socket with a funny identity. */
208 inet->num = lport;
209 inet->sport = htons(lport);
210 sk->sk_hash = hash;
211 BUG_TRAP(sk_unhashed(sk));
212 __sk_add_node(sk, &head->chain);
213 sock_prot_inc_use(sk->sk_prot);
214 write_unlock(&head->lock);
216 if (twp) {
217 *twp = tw;
218 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
219 } else if (tw) {
220 /* Silly. Should hash-dance instead... */
221 inet_twsk_deschedule(tw, death_row);
222 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
224 inet_twsk_put(tw);
227 return 0;
229 not_unique:
230 write_unlock(&head->lock);
231 return -EADDRNOTAVAIL;
234 static inline u32 inet_sk_port_offset(const struct sock *sk)
236 const struct inet_sock *inet = inet_sk(sk);
237 return secure_ipv4_port_ephemeral(inet->rcv_saddr, inet->daddr,
238 inet->dport);
242 * Bind a port for a connect operation and hash it.
244 int inet_hash_connect(struct inet_timewait_death_row *death_row,
245 struct sock *sk)
247 struct inet_hashinfo *hinfo = death_row->hashinfo;
248 const unsigned short snum = inet_sk(sk)->num;
249 struct inet_bind_hashbucket *head;
250 struct inet_bind_bucket *tb;
251 int ret;
253 if (!snum) {
254 int low = sysctl_local_port_range[0];
255 int high = sysctl_local_port_range[1];
256 int range = high - low;
257 int i;
258 int port;
259 static u32 hint;
260 u32 offset = hint + inet_sk_port_offset(sk);
261 struct hlist_node *node;
262 struct inet_timewait_sock *tw = NULL;
264 local_bh_disable();
265 for (i = 1; i <= range; i++) {
266 port = low + (i + offset) % range;
267 head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
268 spin_lock(&head->lock);
270 /* Does not bother with rcv_saddr checks,
271 * because the established check is already
272 * unique enough.
274 inet_bind_bucket_for_each(tb, node, &head->chain) {
275 if (tb->port == port) {
276 BUG_TRAP(!hlist_empty(&tb->owners));
277 if (tb->fastreuse >= 0)
278 goto next_port;
279 if (!__inet_check_established(death_row,
280 sk, port,
281 &tw))
282 goto ok;
283 goto next_port;
287 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, head, port);
288 if (!tb) {
289 spin_unlock(&head->lock);
290 break;
292 tb->fastreuse = -1;
293 goto ok;
295 next_port:
296 spin_unlock(&head->lock);
298 local_bh_enable();
300 return -EADDRNOTAVAIL;
303 hint += i;
305 /* Head lock still held and bh's disabled */
306 inet_bind_hash(sk, tb, port);
307 if (sk_unhashed(sk)) {
308 inet_sk(sk)->sport = htons(port);
309 __inet_hash(hinfo, sk, 0);
311 spin_unlock(&head->lock);
313 if (tw) {
314 inet_twsk_deschedule(tw, death_row);
315 inet_twsk_put(tw);
318 ret = 0;
319 goto out;
322 head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
323 tb = inet_csk(sk)->icsk_bind_hash;
324 spin_lock_bh(&head->lock);
325 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
326 __inet_hash(hinfo, sk, 0);
327 spin_unlock_bh(&head->lock);
328 return 0;
329 } else {
330 spin_unlock(&head->lock);
331 /* No definite answer... Walk to established hash table */
332 ret = __inet_check_established(death_row, sk, snum, NULL);
333 out:
334 local_bh_enable();
335 return ret;
339 EXPORT_SYMBOL_GPL(inet_hash_connect);