diff options
Diffstat (limited to 'net/ipv4/inet_hashtables.c')
| -rw-r--r-- | net/ipv4/inet_hashtables.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c new file mode 100644 index 00000000000..e8d29fe736d --- /dev/null +++ b/net/ipv4/inet_hashtables.c @@ -0,0 +1,165 @@ +/* + * 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 INET transport hashtables + * + * Authors: Lotsa people, from code originally in tcp + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/wait.h> + +#include <net/inet_connection_sock.h> +#include <net/inet_hashtables.h> + +/* + * Allocate and initialize a new local port bind bucket. + * The bindhash mutex for snum's hash chain must be held here. + */ +struct inet_bind_bucket *inet_bind_bucket_create(kmem_cache_t *cachep, + struct inet_bind_hashbucket *head, + const unsigned short snum) +{ + struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, SLAB_ATOMIC); + + if (tb != NULL) { + tb->port = snum; + tb->fastreuse = 0; + INIT_HLIST_HEAD(&tb->owners); + hlist_add_head(&tb->node, &head->chain); + } + return tb; +} + +EXPORT_SYMBOL(inet_bind_bucket_create); + +/* + * Caller must hold hashbucket lock for this tb with local BH disabled + */ +void inet_bind_bucket_destroy(kmem_cache_t *cachep, struct inet_bind_bucket *tb) +{ + if (hlist_empty(&tb->owners)) { + __hlist_del(&tb->node); + kmem_cache_free(cachep, tb); + } +} + +void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, + const unsigned short snum) +{ + inet_sk(sk)->num = snum; + sk_add_bind_node(sk, &tb->owners); + inet_csk(sk)->icsk_bind_hash = tb; +} + +EXPORT_SYMBOL(inet_bind_hash); + +/* + * Get rid of any references to a local port held by the given sock. + */ +static void __inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) +{ + const int bhash = inet_bhashfn(inet_sk(sk)->num, hashinfo->bhash_size); + struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; + struct inet_bind_bucket *tb; + + spin_lock(&head->lock); + tb = inet_csk(sk)->icsk_bind_hash; + __sk_del_bind_node(sk); + inet_csk(sk)->icsk_bind_hash = NULL; + inet_sk(sk)->num = 0; + inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); + spin_unlock(&head->lock); +} + +void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk) +{ + local_bh_disable(); + __inet_put_port(hashinfo, sk); + local_bh_enable(); +} + +EXPORT_SYMBOL(inet_put_port); + +/* + * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP. + * Look, when several writers sleep and reader wakes them up, all but one + * immediately hit write lock and grab all the cpus. Exclusive sleep solves + * this, _but_ remember, it adds useless work on UP machines (wake up each + * exclusive lock release). It should be ifdefed really. + */ +void inet_listen_wlock(struct inet_hashinfo *hashinfo) +{ + write_lock(&hashinfo->lhash_lock); + + if (atomic_read(&hashinfo->lhash_users)) { + DEFINE_WAIT(wait); + + for (;;) { + prepare_to_wait_exclusive(&hashinfo->lhash_wait, + &wait, TASK_UNINTERRUPTIBLE); + if (!atomic_read(&hashinfo->lhash_users)) + break; + write_unlock_bh(&hashinfo->lhash_lock); + schedule(); + write_lock_bh(&hashinfo->lhash_lock); + } + + finish_wait(&hashinfo->lhash_wait, &wait); + } +} + +EXPORT_SYMBOL(inet_listen_wlock); + +/* + * Don't inline this cruft. Here are some nice properties to exploit here. The + * BSD API does not allow a listening sock to specify the remote port nor the + * remote address for the connection. So always assume those are both + * wildcarded during the search since they can never be otherwise. + */ +struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr, + const unsigned short hnum, const int dif) +{ + struct sock *result = NULL, *sk; + const struct hlist_node *node; + int hiscore = -1; + + sk_for_each(sk, node, head) { + const struct inet_sock *inet = inet_sk(sk); + + if (inet->num == hnum && !ipv6_only_sock(sk)) { + const __u32 rcv_saddr = inet->rcv_saddr; + int score = sk->sk_family == PF_INET ? 1 : 0; + + if (rcv_saddr) { + if (rcv_saddr != daddr) + continue; + score += 2; + } + if (sk->sk_bound_dev_if) { + if (sk->sk_bound_dev_if != dif) + continue; + score += 2; + } + if (score == 5) + return sk; + if (score > hiscore) { + hiscore = score; + result = sk; + } + } + } + return result; +} + +EXPORT_SYMBOL_GPL(__inet_lookup_listener); |