![Paul Gortmaker](/assets/img/avatar_default.png)
With calls to modular infrastructure, these files really needs the full module.h header. Call it out so some of the cleanups of implicit and unrequired includes elsewhere can be cleaned up. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
526 lines
14 KiB
C
526 lines
14 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Generic TIME_WAIT sockets functions
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*
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* From code orinally in TCP
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*/
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#include <linux/kernel.h>
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#include <linux/kmemcheck.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <net/inet_hashtables.h>
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#include <net/inet_timewait_sock.h>
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#include <net/ip.h>
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/**
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* inet_twsk_unhash - unhash a timewait socket from established hash
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* @tw: timewait socket
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*
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* unhash a timewait socket from established hash, if hashed.
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* ehash lock must be held by caller.
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* Returns 1 if caller should call inet_twsk_put() after lock release.
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*/
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int inet_twsk_unhash(struct inet_timewait_sock *tw)
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{
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if (hlist_nulls_unhashed(&tw->tw_node))
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return 0;
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hlist_nulls_del_rcu(&tw->tw_node);
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sk_nulls_node_init(&tw->tw_node);
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/*
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* We cannot call inet_twsk_put() ourself under lock,
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* caller must call it for us.
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*/
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return 1;
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}
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/**
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* inet_twsk_bind_unhash - unhash a timewait socket from bind hash
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* @tw: timewait socket
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* @hashinfo: hashinfo pointer
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*
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* unhash a timewait socket from bind hash, if hashed.
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* bind hash lock must be held by caller.
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* Returns 1 if caller should call inet_twsk_put() after lock release.
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*/
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int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
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struct inet_hashinfo *hashinfo)
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{
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struct inet_bind_bucket *tb = tw->tw_tb;
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if (!tb)
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return 0;
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__hlist_del(&tw->tw_bind_node);
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tw->tw_tb = NULL;
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inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
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/*
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* We cannot call inet_twsk_put() ourself under lock,
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* caller must call it for us.
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*/
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return 1;
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}
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/* Must be called with locally disabled BHs. */
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static void __inet_twsk_kill(struct inet_timewait_sock *tw,
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struct inet_hashinfo *hashinfo)
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{
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struct inet_bind_hashbucket *bhead;
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int refcnt;
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/* Unlink from established hashes. */
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spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
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spin_lock(lock);
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refcnt = inet_twsk_unhash(tw);
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spin_unlock(lock);
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/* Disassociate with bind bucket. */
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bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
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hashinfo->bhash_size)];
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spin_lock(&bhead->lock);
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refcnt += inet_twsk_bind_unhash(tw, hashinfo);
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spin_unlock(&bhead->lock);
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#ifdef SOCK_REFCNT_DEBUG
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if (atomic_read(&tw->tw_refcnt) != 1) {
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printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n",
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tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
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}
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#endif
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while (refcnt) {
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inet_twsk_put(tw);
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refcnt--;
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}
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}
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static noinline void inet_twsk_free(struct inet_timewait_sock *tw)
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{
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struct module *owner = tw->tw_prot->owner;
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twsk_destructor((struct sock *)tw);
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#ifdef SOCK_REFCNT_DEBUG
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pr_debug("%s timewait_sock %p released\n", tw->tw_prot->name, tw);
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#endif
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release_net(twsk_net(tw));
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kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw);
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module_put(owner);
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}
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void inet_twsk_put(struct inet_timewait_sock *tw)
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{
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if (atomic_dec_and_test(&tw->tw_refcnt))
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inet_twsk_free(tw);
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}
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EXPORT_SYMBOL_GPL(inet_twsk_put);
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/*
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* Enter the time wait state. This is called with locally disabled BH.
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* Essentially we whip up a timewait bucket, copy the relevant info into it
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* from the SK, and mess with hash chains and list linkage.
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*/
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void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
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struct inet_hashinfo *hashinfo)
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{
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const struct inet_sock *inet = inet_sk(sk);
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const struct inet_connection_sock *icsk = inet_csk(sk);
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struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);
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spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
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struct inet_bind_hashbucket *bhead;
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/* Step 1: Put TW into bind hash. Original socket stays there too.
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Note, that any socket with inet->num != 0 MUST be bound in
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binding cache, even if it is closed.
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*/
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bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
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hashinfo->bhash_size)];
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spin_lock(&bhead->lock);
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tw->tw_tb = icsk->icsk_bind_hash;
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WARN_ON(!icsk->icsk_bind_hash);
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inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
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spin_unlock(&bhead->lock);
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spin_lock(lock);
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/*
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* Step 2: Hash TW into TIMEWAIT chain.
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* Should be done before removing sk from established chain
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* because readers are lockless and search established first.
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*/
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inet_twsk_add_node_rcu(tw, &ehead->twchain);
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/* Step 3: Remove SK from established hash. */
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if (__sk_nulls_del_node_init_rcu(sk))
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
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/*
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* Notes :
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* - We initially set tw_refcnt to 0 in inet_twsk_alloc()
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* - We add one reference for the bhash link
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* - We add one reference for the ehash link
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* - We want this refcnt update done before allowing other
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* threads to find this tw in ehash chain.
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*/
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atomic_add(1 + 1 + 1, &tw->tw_refcnt);
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spin_unlock(lock);
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}
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EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
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struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state)
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{
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struct inet_timewait_sock *tw =
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kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab,
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GFP_ATOMIC);
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if (tw != NULL) {
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const struct inet_sock *inet = inet_sk(sk);
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kmemcheck_annotate_bitfield(tw, flags);
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/* Give us an identity. */
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tw->tw_daddr = inet->inet_daddr;
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tw->tw_rcv_saddr = inet->inet_rcv_saddr;
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tw->tw_bound_dev_if = sk->sk_bound_dev_if;
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tw->tw_tos = inet->tos;
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tw->tw_num = inet->inet_num;
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tw->tw_state = TCP_TIME_WAIT;
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tw->tw_substate = state;
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tw->tw_sport = inet->inet_sport;
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tw->tw_dport = inet->inet_dport;
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tw->tw_family = sk->sk_family;
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tw->tw_reuse = sk->sk_reuse;
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tw->tw_hash = sk->sk_hash;
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tw->tw_ipv6only = 0;
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tw->tw_transparent = inet->transparent;
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tw->tw_prot = sk->sk_prot_creator;
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twsk_net_set(tw, hold_net(sock_net(sk)));
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/*
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* Because we use RCU lookups, we should not set tw_refcnt
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* to a non null value before everything is setup for this
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* timewait socket.
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*/
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atomic_set(&tw->tw_refcnt, 0);
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inet_twsk_dead_node_init(tw);
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__module_get(tw->tw_prot->owner);
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}
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return tw;
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}
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EXPORT_SYMBOL_GPL(inet_twsk_alloc);
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/* Returns non-zero if quota exceeded. */
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static int inet_twdr_do_twkill_work(struct inet_timewait_death_row *twdr,
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const int slot)
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{
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struct inet_timewait_sock *tw;
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struct hlist_node *node;
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unsigned int killed;
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int ret;
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/* NOTE: compare this to previous version where lock
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* was released after detaching chain. It was racy,
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* because tw buckets are scheduled in not serialized context
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* in 2.3 (with netfilter), and with softnet it is common, because
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* soft irqs are not sequenced.
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*/
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killed = 0;
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ret = 0;
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rescan:
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inet_twsk_for_each_inmate(tw, node, &twdr->cells[slot]) {
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__inet_twsk_del_dead_node(tw);
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spin_unlock(&twdr->death_lock);
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__inet_twsk_kill(tw, twdr->hashinfo);
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#ifdef CONFIG_NET_NS
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NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED);
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#endif
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inet_twsk_put(tw);
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killed++;
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spin_lock(&twdr->death_lock);
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if (killed > INET_TWDR_TWKILL_QUOTA) {
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ret = 1;
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break;
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}
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/* While we dropped twdr->death_lock, another cpu may have
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* killed off the next TW bucket in the list, therefore
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* do a fresh re-read of the hlist head node with the
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* lock reacquired. We still use the hlist traversal
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* macro in order to get the prefetches.
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*/
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goto rescan;
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}
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twdr->tw_count -= killed;
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#ifndef CONFIG_NET_NS
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NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITED, killed);
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#endif
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return ret;
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}
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void inet_twdr_hangman(unsigned long data)
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{
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struct inet_timewait_death_row *twdr;
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int unsigned need_timer;
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twdr = (struct inet_timewait_death_row *)data;
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spin_lock(&twdr->death_lock);
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if (twdr->tw_count == 0)
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goto out;
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need_timer = 0;
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if (inet_twdr_do_twkill_work(twdr, twdr->slot)) {
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twdr->thread_slots |= (1 << twdr->slot);
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schedule_work(&twdr->twkill_work);
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need_timer = 1;
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} else {
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/* We purged the entire slot, anything left? */
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if (twdr->tw_count)
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need_timer = 1;
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twdr->slot = ((twdr->slot + 1) & (INET_TWDR_TWKILL_SLOTS - 1));
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}
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if (need_timer)
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mod_timer(&twdr->tw_timer, jiffies + twdr->period);
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out:
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spin_unlock(&twdr->death_lock);
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}
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EXPORT_SYMBOL_GPL(inet_twdr_hangman);
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void inet_twdr_twkill_work(struct work_struct *work)
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{
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struct inet_timewait_death_row *twdr =
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container_of(work, struct inet_timewait_death_row, twkill_work);
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int i;
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BUILD_BUG_ON((INET_TWDR_TWKILL_SLOTS - 1) >
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(sizeof(twdr->thread_slots) * 8));
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while (twdr->thread_slots) {
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spin_lock_bh(&twdr->death_lock);
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for (i = 0; i < INET_TWDR_TWKILL_SLOTS; i++) {
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if (!(twdr->thread_slots & (1 << i)))
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continue;
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while (inet_twdr_do_twkill_work(twdr, i) != 0) {
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if (need_resched()) {
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spin_unlock_bh(&twdr->death_lock);
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schedule();
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spin_lock_bh(&twdr->death_lock);
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}
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}
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twdr->thread_slots &= ~(1 << i);
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}
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spin_unlock_bh(&twdr->death_lock);
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}
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}
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EXPORT_SYMBOL_GPL(inet_twdr_twkill_work);
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/* These are always called from BH context. See callers in
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* tcp_input.c to verify this.
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*/
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/* This is for handling early-kills of TIME_WAIT sockets. */
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void inet_twsk_deschedule(struct inet_timewait_sock *tw,
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struct inet_timewait_death_row *twdr)
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{
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spin_lock(&twdr->death_lock);
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if (inet_twsk_del_dead_node(tw)) {
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inet_twsk_put(tw);
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if (--twdr->tw_count == 0)
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del_timer(&twdr->tw_timer);
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}
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spin_unlock(&twdr->death_lock);
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__inet_twsk_kill(tw, twdr->hashinfo);
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}
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EXPORT_SYMBOL(inet_twsk_deschedule);
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void inet_twsk_schedule(struct inet_timewait_sock *tw,
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struct inet_timewait_death_row *twdr,
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const int timeo, const int timewait_len)
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{
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struct hlist_head *list;
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int slot;
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/* timeout := RTO * 3.5
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*
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* 3.5 = 1+2+0.5 to wait for two retransmits.
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*
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* RATIONALE: if FIN arrived and we entered TIME-WAIT state,
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* our ACK acking that FIN can be lost. If N subsequent retransmitted
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* FINs (or previous seqments) are lost (probability of such event
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* is p^(N+1), where p is probability to lose single packet and
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* time to detect the loss is about RTO*(2^N - 1) with exponential
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* backoff). Normal timewait length is calculated so, that we
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* waited at least for one retransmitted FIN (maximal RTO is 120sec).
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* [ BTW Linux. following BSD, violates this requirement waiting
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* only for 60sec, we should wait at least for 240 secs.
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* Well, 240 consumes too much of resources 8)
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* ]
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* This interval is not reduced to catch old duplicate and
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* responces to our wandering segments living for two MSLs.
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* However, if we use PAWS to detect
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* old duplicates, we can reduce the interval to bounds required
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* by RTO, rather than MSL. So, if peer understands PAWS, we
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* kill tw bucket after 3.5*RTO (it is important that this number
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* is greater than TS tick!) and detect old duplicates with help
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* of PAWS.
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*/
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slot = (timeo + (1 << INET_TWDR_RECYCLE_TICK) - 1) >> INET_TWDR_RECYCLE_TICK;
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spin_lock(&twdr->death_lock);
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/* Unlink it, if it was scheduled */
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if (inet_twsk_del_dead_node(tw))
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twdr->tw_count--;
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else
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atomic_inc(&tw->tw_refcnt);
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if (slot >= INET_TWDR_RECYCLE_SLOTS) {
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/* Schedule to slow timer */
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if (timeo >= timewait_len) {
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slot = INET_TWDR_TWKILL_SLOTS - 1;
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} else {
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slot = DIV_ROUND_UP(timeo, twdr->period);
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if (slot >= INET_TWDR_TWKILL_SLOTS)
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slot = INET_TWDR_TWKILL_SLOTS - 1;
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}
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tw->tw_ttd = jiffies + timeo;
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slot = (twdr->slot + slot) & (INET_TWDR_TWKILL_SLOTS - 1);
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list = &twdr->cells[slot];
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} else {
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tw->tw_ttd = jiffies + (slot << INET_TWDR_RECYCLE_TICK);
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if (twdr->twcal_hand < 0) {
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twdr->twcal_hand = 0;
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twdr->twcal_jiffie = jiffies;
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twdr->twcal_timer.expires = twdr->twcal_jiffie +
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(slot << INET_TWDR_RECYCLE_TICK);
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add_timer(&twdr->twcal_timer);
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} else {
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if (time_after(twdr->twcal_timer.expires,
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jiffies + (slot << INET_TWDR_RECYCLE_TICK)))
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mod_timer(&twdr->twcal_timer,
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jiffies + (slot << INET_TWDR_RECYCLE_TICK));
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slot = (twdr->twcal_hand + slot) & (INET_TWDR_RECYCLE_SLOTS - 1);
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}
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list = &twdr->twcal_row[slot];
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}
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hlist_add_head(&tw->tw_death_node, list);
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if (twdr->tw_count++ == 0)
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mod_timer(&twdr->tw_timer, jiffies + twdr->period);
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spin_unlock(&twdr->death_lock);
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}
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EXPORT_SYMBOL_GPL(inet_twsk_schedule);
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void inet_twdr_twcal_tick(unsigned long data)
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{
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struct inet_timewait_death_row *twdr;
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int n, slot;
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unsigned long j;
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unsigned long now = jiffies;
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int killed = 0;
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int adv = 0;
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twdr = (struct inet_timewait_death_row *)data;
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spin_lock(&twdr->death_lock);
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if (twdr->twcal_hand < 0)
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goto out;
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slot = twdr->twcal_hand;
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j = twdr->twcal_jiffie;
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for (n = 0; n < INET_TWDR_RECYCLE_SLOTS; n++) {
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if (time_before_eq(j, now)) {
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struct hlist_node *node, *safe;
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struct inet_timewait_sock *tw;
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inet_twsk_for_each_inmate_safe(tw, node, safe,
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&twdr->twcal_row[slot]) {
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__inet_twsk_del_dead_node(tw);
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__inet_twsk_kill(tw, twdr->hashinfo);
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#ifdef CONFIG_NET_NS
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NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED);
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#endif
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inet_twsk_put(tw);
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killed++;
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}
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} else {
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if (!adv) {
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adv = 1;
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twdr->twcal_jiffie = j;
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twdr->twcal_hand = slot;
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}
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if (!hlist_empty(&twdr->twcal_row[slot])) {
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mod_timer(&twdr->twcal_timer, j);
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goto out;
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}
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}
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j += 1 << INET_TWDR_RECYCLE_TICK;
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slot = (slot + 1) & (INET_TWDR_RECYCLE_SLOTS - 1);
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|
}
|
|
twdr->twcal_hand = -1;
|
|
|
|
out:
|
|
if ((twdr->tw_count -= killed) == 0)
|
|
del_timer(&twdr->tw_timer);
|
|
#ifndef CONFIG_NET_NS
|
|
NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITKILLED, killed);
|
|
#endif
|
|
spin_unlock(&twdr->death_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);
|
|
|
|
void inet_twsk_purge(struct inet_hashinfo *hashinfo,
|
|
struct inet_timewait_death_row *twdr, int family)
|
|
{
|
|
struct inet_timewait_sock *tw;
|
|
struct sock *sk;
|
|
struct hlist_nulls_node *node;
|
|
unsigned int slot;
|
|
|
|
for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
|
|
struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
|
|
restart_rcu:
|
|
rcu_read_lock();
|
|
restart:
|
|
sk_nulls_for_each_rcu(sk, node, &head->twchain) {
|
|
tw = inet_twsk(sk);
|
|
if ((tw->tw_family != family) ||
|
|
atomic_read(&twsk_net(tw)->count))
|
|
continue;
|
|
|
|
if (unlikely(!atomic_inc_not_zero(&tw->tw_refcnt)))
|
|
continue;
|
|
|
|
if (unlikely((tw->tw_family != family) ||
|
|
atomic_read(&twsk_net(tw)->count))) {
|
|
inet_twsk_put(tw);
|
|
goto restart;
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
local_bh_disable();
|
|
inet_twsk_deschedule(tw, twdr);
|
|
local_bh_enable();
|
|
inet_twsk_put(tw);
|
|
goto restart_rcu;
|
|
}
|
|
/* 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();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(inet_twsk_purge);
|