modpost: add support for hid
[linux-2.6/mini2440.git] / net / ipv4 / inet_hashtables.c
blob44981906fb913e7afbb4f7e03cd0192b9fdcda12
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/module.h>
17 #include <linux/random.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/wait.h>
22 #include <net/inet_connection_sock.h>
23 #include <net/inet_hashtables.h>
24 #include <net/ip.h>
27 * Allocate and initialize a new local port bind bucket.
28 * The bindhash mutex for snum's hash chain must be held here.
30 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
31 struct net *net,
32 struct inet_bind_hashbucket *head,
33 const unsigned short snum)
35 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
37 if (tb != NULL) {
38 tb->ib_net = hold_net(net);
39 tb->port = snum;
40 tb->fastreuse = 0;
41 INIT_HLIST_HEAD(&tb->owners);
42 hlist_add_head(&tb->node, &head->chain);
44 return tb;
48 * Caller must hold hashbucket lock for this tb with local BH disabled
50 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
52 if (hlist_empty(&tb->owners)) {
53 __hlist_del(&tb->node);
54 release_net(tb->ib_net);
55 kmem_cache_free(cachep, tb);
59 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
60 const unsigned short snum)
62 inet_sk(sk)->num = snum;
63 sk_add_bind_node(sk, &tb->owners);
64 inet_csk(sk)->icsk_bind_hash = tb;
68 * Get rid of any references to a local port held by the given sock.
70 static void __inet_put_port(struct sock *sk)
72 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
73 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->num,
74 hashinfo->bhash_size);
75 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
76 struct inet_bind_bucket *tb;
78 spin_lock(&head->lock);
79 tb = inet_csk(sk)->icsk_bind_hash;
80 __sk_del_bind_node(sk);
81 inet_csk(sk)->icsk_bind_hash = NULL;
82 inet_sk(sk)->num = 0;
83 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
84 spin_unlock(&head->lock);
87 void inet_put_port(struct sock *sk)
89 local_bh_disable();
90 __inet_put_port(sk);
91 local_bh_enable();
94 EXPORT_SYMBOL(inet_put_port);
96 void __inet_inherit_port(struct sock *sk, struct sock *child)
98 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
99 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(child)->num,
100 table->bhash_size);
101 struct inet_bind_hashbucket *head = &table->bhash[bhash];
102 struct inet_bind_bucket *tb;
104 spin_lock(&head->lock);
105 tb = inet_csk(sk)->icsk_bind_hash;
106 sk_add_bind_node(child, &tb->owners);
107 inet_csk(child)->icsk_bind_hash = tb;
108 spin_unlock(&head->lock);
111 EXPORT_SYMBOL_GPL(__inet_inherit_port);
114 * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
115 * Look, when several writers sleep and reader wakes them up, all but one
116 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
117 * this, _but_ remember, it adds useless work on UP machines (wake up each
118 * exclusive lock release). It should be ifdefed really.
120 void inet_listen_wlock(struct inet_hashinfo *hashinfo)
121 __acquires(hashinfo->lhash_lock)
123 write_lock(&hashinfo->lhash_lock);
125 if (atomic_read(&hashinfo->lhash_users)) {
126 DEFINE_WAIT(wait);
128 for (;;) {
129 prepare_to_wait_exclusive(&hashinfo->lhash_wait,
130 &wait, TASK_UNINTERRUPTIBLE);
131 if (!atomic_read(&hashinfo->lhash_users))
132 break;
133 write_unlock_bh(&hashinfo->lhash_lock);
134 schedule();
135 write_lock_bh(&hashinfo->lhash_lock);
138 finish_wait(&hashinfo->lhash_wait, &wait);
143 * Don't inline this cruft. Here are some nice properties to exploit here. The
144 * BSD API does not allow a listening sock to specify the remote port nor the
145 * remote address for the connection. So always assume those are both
146 * wildcarded during the search since they can never be otherwise.
148 static struct sock *inet_lookup_listener_slow(struct net *net,
149 const struct hlist_head *head,
150 const __be32 daddr,
151 const unsigned short hnum,
152 const int dif)
154 struct sock *result = NULL, *sk;
155 const struct hlist_node *node;
156 int hiscore = -1;
158 sk_for_each(sk, node, head) {
159 const struct inet_sock *inet = inet_sk(sk);
161 if (net_eq(sock_net(sk), net) && inet->num == hnum &&
162 !ipv6_only_sock(sk)) {
163 const __be32 rcv_saddr = inet->rcv_saddr;
164 int score = sk->sk_family == PF_INET ? 1 : 0;
166 if (rcv_saddr) {
167 if (rcv_saddr != daddr)
168 continue;
169 score += 2;
171 if (sk->sk_bound_dev_if) {
172 if (sk->sk_bound_dev_if != dif)
173 continue;
174 score += 2;
176 if (score == 5)
177 return sk;
178 if (score > hiscore) {
179 hiscore = score;
180 result = sk;
184 return result;
187 /* Optimize the common listener case. */
188 struct sock *__inet_lookup_listener(struct net *net,
189 struct inet_hashinfo *hashinfo,
190 const __be32 daddr, const unsigned short hnum,
191 const int dif)
193 struct sock *sk = NULL;
194 const struct hlist_head *head;
196 read_lock(&hashinfo->lhash_lock);
197 head = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
198 if (!hlist_empty(head)) {
199 const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
201 if (inet->num == hnum && !sk->sk_node.next &&
202 (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
203 (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
204 !sk->sk_bound_dev_if && net_eq(sock_net(sk), net))
205 goto sherry_cache;
206 sk = inet_lookup_listener_slow(net, head, daddr, hnum, dif);
208 if (sk) {
209 sherry_cache:
210 sock_hold(sk);
212 read_unlock(&hashinfo->lhash_lock);
213 return sk;
215 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
217 struct sock * __inet_lookup_established(struct net *net,
218 struct inet_hashinfo *hashinfo,
219 const __be32 saddr, const __be16 sport,
220 const __be32 daddr, const u16 hnum,
221 const int dif)
223 INET_ADDR_COOKIE(acookie, saddr, daddr)
224 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
225 struct sock *sk;
226 const struct hlist_node *node;
227 /* Optimize here for direct hit, only listening connections can
228 * have wildcards anyways.
230 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
231 struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
232 rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
234 prefetch(head->chain.first);
235 read_lock(lock);
236 sk_for_each(sk, node, &head->chain) {
237 if (INET_MATCH(sk, net, hash, acookie,
238 saddr, daddr, ports, dif))
239 goto hit; /* You sunk my battleship! */
242 /* Must check for a TIME_WAIT'er before going to listener hash. */
243 sk_for_each(sk, node, &head->twchain) {
244 if (INET_TW_MATCH(sk, net, hash, acookie,
245 saddr, daddr, ports, dif))
246 goto hit;
248 sk = NULL;
249 out:
250 read_unlock(lock);
251 return sk;
252 hit:
253 sock_hold(sk);
254 goto out;
256 EXPORT_SYMBOL_GPL(__inet_lookup_established);
258 /* called with local bh disabled */
259 static int __inet_check_established(struct inet_timewait_death_row *death_row,
260 struct sock *sk, __u16 lport,
261 struct inet_timewait_sock **twp)
263 struct inet_hashinfo *hinfo = death_row->hashinfo;
264 struct inet_sock *inet = inet_sk(sk);
265 __be32 daddr = inet->rcv_saddr;
266 __be32 saddr = inet->daddr;
267 int dif = sk->sk_bound_dev_if;
268 INET_ADDR_COOKIE(acookie, saddr, daddr)
269 const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport);
270 struct net *net = sock_net(sk);
271 unsigned int hash = inet_ehashfn(net, daddr, lport, saddr, inet->dport);
272 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
273 rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
274 struct sock *sk2;
275 const struct hlist_node *node;
276 struct inet_timewait_sock *tw;
278 prefetch(head->chain.first);
279 write_lock(lock);
281 /* Check TIME-WAIT sockets first. */
282 sk_for_each(sk2, node, &head->twchain) {
283 tw = inet_twsk(sk2);
285 if (INET_TW_MATCH(sk2, net, hash, acookie,
286 saddr, daddr, ports, dif)) {
287 if (twsk_unique(sk, sk2, twp))
288 goto unique;
289 else
290 goto not_unique;
293 tw = NULL;
295 /* And established part... */
296 sk_for_each(sk2, node, &head->chain) {
297 if (INET_MATCH(sk2, net, hash, acookie,
298 saddr, daddr, ports, dif))
299 goto not_unique;
302 unique:
303 /* Must record num and sport now. Otherwise we will see
304 * in hash table socket with a funny identity. */
305 inet->num = lport;
306 inet->sport = htons(lport);
307 sk->sk_hash = hash;
308 WARN_ON(!sk_unhashed(sk));
309 __sk_add_node(sk, &head->chain);
310 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
311 write_unlock(lock);
313 if (twp) {
314 *twp = tw;
315 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
316 } else if (tw) {
317 /* Silly. Should hash-dance instead... */
318 inet_twsk_deschedule(tw, death_row);
319 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
321 inet_twsk_put(tw);
324 return 0;
326 not_unique:
327 write_unlock(lock);
328 return -EADDRNOTAVAIL;
331 static inline u32 inet_sk_port_offset(const struct sock *sk)
333 const struct inet_sock *inet = inet_sk(sk);
334 return secure_ipv4_port_ephemeral(inet->rcv_saddr, inet->daddr,
335 inet->dport);
338 void __inet_hash_nolisten(struct sock *sk)
340 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
341 struct hlist_head *list;
342 rwlock_t *lock;
343 struct inet_ehash_bucket *head;
345 WARN_ON(!sk_unhashed(sk));
347 sk->sk_hash = inet_sk_ehashfn(sk);
348 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
349 list = &head->chain;
350 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
352 write_lock(lock);
353 __sk_add_node(sk, list);
354 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
355 write_unlock(lock);
357 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
359 static void __inet_hash(struct sock *sk)
361 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
362 struct hlist_head *list;
363 rwlock_t *lock;
365 if (sk->sk_state != TCP_LISTEN) {
366 __inet_hash_nolisten(sk);
367 return;
370 WARN_ON(!sk_unhashed(sk));
371 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
372 lock = &hashinfo->lhash_lock;
374 inet_listen_wlock(hashinfo);
375 __sk_add_node(sk, list);
376 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
377 write_unlock(lock);
378 wake_up(&hashinfo->lhash_wait);
381 void inet_hash(struct sock *sk)
383 if (sk->sk_state != TCP_CLOSE) {
384 local_bh_disable();
385 __inet_hash(sk);
386 local_bh_enable();
389 EXPORT_SYMBOL_GPL(inet_hash);
391 void inet_unhash(struct sock *sk)
393 rwlock_t *lock;
394 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
396 if (sk_unhashed(sk))
397 goto out;
399 if (sk->sk_state == TCP_LISTEN) {
400 local_bh_disable();
401 inet_listen_wlock(hashinfo);
402 lock = &hashinfo->lhash_lock;
403 } else {
404 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
405 write_lock_bh(lock);
408 if (__sk_del_node_init(sk))
409 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
410 write_unlock_bh(lock);
411 out:
412 if (sk->sk_state == TCP_LISTEN)
413 wake_up(&hashinfo->lhash_wait);
415 EXPORT_SYMBOL_GPL(inet_unhash);
417 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
418 struct sock *sk, u32 port_offset,
419 int (*check_established)(struct inet_timewait_death_row *,
420 struct sock *, __u16, struct inet_timewait_sock **),
421 void (*hash)(struct sock *sk))
423 struct inet_hashinfo *hinfo = death_row->hashinfo;
424 const unsigned short snum = inet_sk(sk)->num;
425 struct inet_bind_hashbucket *head;
426 struct inet_bind_bucket *tb;
427 int ret;
428 struct net *net = sock_net(sk);
430 if (!snum) {
431 int i, remaining, low, high, port;
432 static u32 hint;
433 u32 offset = hint + port_offset;
434 struct hlist_node *node;
435 struct inet_timewait_sock *tw = NULL;
437 inet_get_local_port_range(&low, &high);
438 remaining = (high - low) + 1;
440 local_bh_disable();
441 for (i = 1; i <= remaining; i++) {
442 port = low + (i + offset) % remaining;
443 head = &hinfo->bhash[inet_bhashfn(net, port,
444 hinfo->bhash_size)];
445 spin_lock(&head->lock);
447 /* Does not bother with rcv_saddr checks,
448 * because the established check is already
449 * unique enough.
451 inet_bind_bucket_for_each(tb, node, &head->chain) {
452 if (tb->ib_net == net && tb->port == port) {
453 WARN_ON(hlist_empty(&tb->owners));
454 if (tb->fastreuse >= 0)
455 goto next_port;
456 if (!check_established(death_row, sk,
457 port, &tw))
458 goto ok;
459 goto next_port;
463 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
464 net, head, port);
465 if (!tb) {
466 spin_unlock(&head->lock);
467 break;
469 tb->fastreuse = -1;
470 goto ok;
472 next_port:
473 spin_unlock(&head->lock);
475 local_bh_enable();
477 return -EADDRNOTAVAIL;
480 hint += i;
482 /* Head lock still held and bh's disabled */
483 inet_bind_hash(sk, tb, port);
484 if (sk_unhashed(sk)) {
485 inet_sk(sk)->sport = htons(port);
486 hash(sk);
488 spin_unlock(&head->lock);
490 if (tw) {
491 inet_twsk_deschedule(tw, death_row);
492 inet_twsk_put(tw);
495 ret = 0;
496 goto out;
499 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
500 tb = inet_csk(sk)->icsk_bind_hash;
501 spin_lock_bh(&head->lock);
502 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
503 hash(sk);
504 spin_unlock_bh(&head->lock);
505 return 0;
506 } else {
507 spin_unlock(&head->lock);
508 /* No definite answer... Walk to established hash table */
509 ret = check_established(death_row, sk, snum, NULL);
510 out:
511 local_bh_enable();
512 return ret;
517 * Bind a port for a connect operation and hash it.
519 int inet_hash_connect(struct inet_timewait_death_row *death_row,
520 struct sock *sk)
522 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
523 __inet_check_established, __inet_hash_nolisten);
526 EXPORT_SYMBOL_GPL(inet_hash_connect);