| /* |
| * 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/module.h> |
| #include <linux/random.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/wait.h> |
| |
| #include <net/inet_connection_sock.h> |
| #include <net/inet_hashtables.h> |
| #include <net/ip.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(struct kmem_cache *cachep, |
| struct inet_bind_hashbucket *head, |
| const unsigned short snum) |
| { |
| struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC); |
| |
| if (tb != NULL) { |
| tb->port = snum; |
| tb->fastreuse = 0; |
| INIT_HLIST_HEAD(&tb->owners); |
| hlist_add_head(&tb->node, &head->chain); |
| } |
| return tb; |
| } |
| |
| /* |
| * Caller must hold hashbucket lock for this tb with local BH disabled |
| */ |
| void inet_bind_bucket_destroy(struct kmem_cache *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; |
| } |
| |
| /* |
| * 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) |
| __acquires(hashinfo->lhash_lock) |
| { |
| 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. |
| */ |
| static struct sock *inet_lookup_listener_slow(const struct hlist_head *head, |
| const __be32 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 __be32 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; |
| } |
| |
| /* Optimize the common listener case. */ |
| struct sock *__inet_lookup_listener(struct inet_hashinfo *hashinfo, |
| const __be32 daddr, const unsigned short hnum, |
| const int dif) |
| { |
| struct sock *sk = NULL; |
| const struct hlist_head *head; |
| |
| read_lock(&hashinfo->lhash_lock); |
| head = &hashinfo->listening_hash[inet_lhashfn(hnum)]; |
| if (!hlist_empty(head)) { |
| const struct inet_sock *inet = inet_sk((sk = __sk_head(head))); |
| |
| if (inet->num == hnum && !sk->sk_node.next && |
| (!inet->rcv_saddr || inet->rcv_saddr == daddr) && |
| (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) && |
| !sk->sk_bound_dev_if) |
| goto sherry_cache; |
| sk = inet_lookup_listener_slow(head, daddr, hnum, dif); |
| } |
| if (sk) { |
| sherry_cache: |
| sock_hold(sk); |
| } |
| read_unlock(&hashinfo->lhash_lock); |
| return sk; |
| } |
| EXPORT_SYMBOL_GPL(__inet_lookup_listener); |
| |
| struct sock * __inet_lookup_established(struct inet_hashinfo *hashinfo, |
| const __be32 saddr, const __be16 sport, |
| const __be32 daddr, const u16 hnum, |
| const int dif) |
| { |
| INET_ADDR_COOKIE(acookie, saddr, daddr) |
| const __portpair ports = INET_COMBINED_PORTS(sport, hnum); |
| struct sock *sk; |
| const struct hlist_node *node; |
| /* Optimize here for direct hit, only listening connections can |
| * have wildcards anyways. |
| */ |
| unsigned int hash = inet_ehashfn(daddr, hnum, saddr, sport); |
| struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash); |
| rwlock_t *lock = inet_ehash_lockp(hashinfo, hash); |
| |
| prefetch(head->chain.first); |
| read_lock(lock); |
| sk_for_each(sk, node, &head->chain) { |
| if (INET_MATCH(sk, hash, acookie, saddr, daddr, ports, dif)) |
| goto hit; /* You sunk my battleship! */ |
| } |
| |
| /* Must check for a TIME_WAIT'er before going to listener hash. */ |
| sk_for_each(sk, node, &head->twchain) { |
| if (INET_TW_MATCH(sk, hash, acookie, saddr, daddr, ports, dif)) |
| goto hit; |
| } |
| sk = NULL; |
| out: |
| read_unlock(lock); |
| return sk; |
| hit: |
| sock_hold(sk); |
| goto out; |
| } |
| EXPORT_SYMBOL_GPL(__inet_lookup_established); |
| |
| /* called with local bh disabled */ |
| static int __inet_check_established(struct inet_timewait_death_row *death_row, |
| struct sock *sk, __u16 lport, |
| struct inet_timewait_sock **twp) |
| { |
| struct inet_hashinfo *hinfo = death_row->hashinfo; |
| struct inet_sock *inet = inet_sk(sk); |
| __be32 daddr = inet->rcv_saddr; |
| __be32 saddr = inet->daddr; |
| int dif = sk->sk_bound_dev_if; |
| INET_ADDR_COOKIE(acookie, saddr, daddr) |
| const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport); |
| unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport); |
| struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); |
| rwlock_t *lock = inet_ehash_lockp(hinfo, hash); |
| struct sock *sk2; |
| const struct hlist_node *node; |
| struct inet_timewait_sock *tw; |
| |
| prefetch(head->chain.first); |
| write_lock(lock); |
| |
| /* Check TIME-WAIT sockets first. */ |
| sk_for_each(sk2, node, &head->twchain) { |
| tw = inet_twsk(sk2); |
| |
| if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) { |
| if (twsk_unique(sk, sk2, twp)) |
| goto unique; |
| else |
| goto not_unique; |
| } |
| } |
| tw = NULL; |
| |
| /* And established part... */ |
| sk_for_each(sk2, node, &head->chain) { |
| if (INET_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) |
| goto not_unique; |
| } |
| |
| unique: |
| /* Must record num and sport now. Otherwise we will see |
| * in hash table socket with a funny identity. */ |
| inet->num = lport; |
| inet->sport = htons(lport); |
| sk->sk_hash = hash; |
| BUG_TRAP(sk_unhashed(sk)); |
| __sk_add_node(sk, &head->chain); |
| sock_prot_inuse_add(sk->sk_prot, 1); |
| write_unlock(lock); |
| |
| if (twp) { |
| *twp = tw; |
| NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); |
| } else if (tw) { |
| /* Silly. Should hash-dance instead... */ |
| inet_twsk_deschedule(tw, death_row); |
| NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); |
| |
| inet_twsk_put(tw); |
| } |
| |
| return 0; |
| |
| not_unique: |
| write_unlock(lock); |
| return -EADDRNOTAVAIL; |
| } |
| |
| static inline u32 inet_sk_port_offset(const struct sock *sk) |
| { |
| const struct inet_sock *inet = inet_sk(sk); |
| return secure_ipv4_port_ephemeral(inet->rcv_saddr, inet->daddr, |
| inet->dport); |
| } |
| |
| void __inet_hash_nolisten(struct inet_hashinfo *hashinfo, struct sock *sk) |
| { |
| struct hlist_head *list; |
| rwlock_t *lock; |
| struct inet_ehash_bucket *head; |
| |
| BUG_TRAP(sk_unhashed(sk)); |
| |
| sk->sk_hash = inet_sk_ehashfn(sk); |
| head = inet_ehash_bucket(hashinfo, sk->sk_hash); |
| list = &head->chain; |
| lock = inet_ehash_lockp(hashinfo, sk->sk_hash); |
| |
| write_lock(lock); |
| __sk_add_node(sk, list); |
| sock_prot_inuse_add(sk->sk_prot, 1); |
| write_unlock(lock); |
| } |
| EXPORT_SYMBOL_GPL(__inet_hash_nolisten); |
| |
| void __inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk) |
| { |
| struct hlist_head *list; |
| rwlock_t *lock; |
| |
| if (sk->sk_state != TCP_LISTEN) { |
| __inet_hash_nolisten(hashinfo, sk); |
| return; |
| } |
| |
| BUG_TRAP(sk_unhashed(sk)); |
| list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; |
| lock = &hashinfo->lhash_lock; |
| |
| inet_listen_wlock(hashinfo); |
| __sk_add_node(sk, list); |
| sock_prot_inuse_add(sk->sk_prot, 1); |
| write_unlock(lock); |
| wake_up(&hashinfo->lhash_wait); |
| } |
| EXPORT_SYMBOL_GPL(__inet_hash); |
| |
| int __inet_hash_connect(struct inet_timewait_death_row *death_row, |
| struct sock *sk, |
| int (*check_established)(struct inet_timewait_death_row *, |
| struct sock *, __u16, struct inet_timewait_sock **), |
| void (*hash)(struct inet_hashinfo *, struct sock *)) |
| { |
| struct inet_hashinfo *hinfo = death_row->hashinfo; |
| const unsigned short snum = inet_sk(sk)->num; |
| struct inet_bind_hashbucket *head; |
| struct inet_bind_bucket *tb; |
| int ret; |
| |
| if (!snum) { |
| int i, remaining, low, high, port; |
| static u32 hint; |
| u32 offset = hint + inet_sk_port_offset(sk); |
| struct hlist_node *node; |
| struct inet_timewait_sock *tw = NULL; |
| |
| inet_get_local_port_range(&low, &high); |
| remaining = (high - low) + 1; |
| |
| local_bh_disable(); |
| for (i = 1; i <= remaining; i++) { |
| port = low + (i + offset) % remaining; |
| head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)]; |
| spin_lock(&head->lock); |
| |
| /* Does not bother with rcv_saddr checks, |
| * because the established check is already |
| * unique enough. |
| */ |
| inet_bind_bucket_for_each(tb, node, &head->chain) { |
| if (tb->port == port) { |
| BUG_TRAP(!hlist_empty(&tb->owners)); |
| if (tb->fastreuse >= 0) |
| goto next_port; |
| if (!check_established(death_row, sk, |
| port, &tw)) |
| goto ok; |
| goto next_port; |
| } |
| } |
| |
| tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, head, port); |
| if (!tb) { |
| spin_unlock(&head->lock); |
| break; |
| } |
| tb->fastreuse = -1; |
| goto ok; |
| |
| next_port: |
| spin_unlock(&head->lock); |
| } |
| local_bh_enable(); |
| |
| return -EADDRNOTAVAIL; |
| |
| ok: |
| hint += i; |
| |
| /* Head lock still held and bh's disabled */ |
| inet_bind_hash(sk, tb, port); |
| if (sk_unhashed(sk)) { |
| inet_sk(sk)->sport = htons(port); |
| hash(hinfo, sk); |
| } |
| spin_unlock(&head->lock); |
| |
| if (tw) { |
| inet_twsk_deschedule(tw, death_row); |
| inet_twsk_put(tw); |
| } |
| |
| ret = 0; |
| goto out; |
| } |
| |
| head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)]; |
| tb = inet_csk(sk)->icsk_bind_hash; |
| spin_lock_bh(&head->lock); |
| if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) { |
| hash(hinfo, sk); |
| spin_unlock_bh(&head->lock); |
| return 0; |
| } else { |
| spin_unlock(&head->lock); |
| /* No definite answer... Walk to established hash table */ |
| ret = check_established(death_row, sk, snum, NULL); |
| out: |
| local_bh_enable(); |
| return ret; |
| } |
| } |
| EXPORT_SYMBOL_GPL(__inet_hash_connect); |
| |
| /* |
| * Bind a port for a connect operation and hash it. |
| */ |
| int inet_hash_connect(struct inet_timewait_death_row *death_row, |
| struct sock *sk) |
| { |
| return __inet_hash_connect(death_row, sk, |
| __inet_check_established, __inet_hash_nolisten); |
| } |
| |
| EXPORT_SYMBOL_GPL(inet_hash_connect); |