280 lines
7.5 KiB
C
280 lines
7.5 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 INET6 transport hashtables
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*
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* Authors: Lotsa people, from code originally in tcp, generalised here
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* by Arnaldo Carvalho de Melo <acme@mandriva.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/random.h>
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#include <net/inet_connection_sock.h>
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#include <net/inet_hashtables.h>
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#include <net/inet6_hashtables.h>
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#include <net/secure_seq.h>
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#include <net/ip.h>
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u32 inet6_ehashfn(const struct net *net,
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const struct in6_addr *laddr, const u16 lport,
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const struct in6_addr *faddr, const __be16 fport)
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{
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static u32 inet6_ehash_secret __read_mostly;
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static u32 ipv6_hash_secret __read_mostly;
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u32 lhash, fhash;
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net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
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net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));
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lhash = (__force u32)laddr->s6_addr32[3];
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fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);
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return __inet6_ehashfn(lhash, lport, fhash, fport,
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inet6_ehash_secret + net_hash_mix(net));
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}
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/*
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* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
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* we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
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*
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* The sockhash lock must be held as a reader here.
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*/
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struct sock *__inet6_lookup_established(struct net *net,
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struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr,
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const __be16 sport,
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const struct in6_addr *daddr,
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const u16 hnum,
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const int dif)
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{
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struct sock *sk;
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const struct hlist_nulls_node *node;
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const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
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/* Optimize here for direct hit, only listening connections can
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* have wildcards anyways.
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*/
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unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
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unsigned int slot = hash & hashinfo->ehash_mask;
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struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
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rcu_read_lock();
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begin:
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sk_nulls_for_each_rcu(sk, node, &head->chain) {
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if (sk->sk_hash != hash)
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continue;
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if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif))
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continue;
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if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
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goto out;
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if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
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sock_gen_put(sk);
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goto begin;
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}
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goto found;
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}
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if (get_nulls_value(node) != slot)
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goto begin;
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out:
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sk = NULL;
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found:
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rcu_read_unlock();
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return sk;
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}
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EXPORT_SYMBOL(__inet6_lookup_established);
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static inline int compute_score(struct sock *sk, struct net *net,
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const unsigned short hnum,
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const struct in6_addr *daddr,
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const int dif)
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{
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int score = -1;
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if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
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sk->sk_family == PF_INET6) {
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score = 1;
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if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
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if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
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return -1;
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score++;
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}
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if (sk->sk_bound_dev_if) {
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if (sk->sk_bound_dev_if != dif)
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return -1;
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score++;
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}
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}
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return score;
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}
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struct sock *inet6_lookup_listener(struct net *net,
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struct inet_hashinfo *hashinfo, const struct in6_addr *saddr,
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const __be16 sport, const struct in6_addr *daddr,
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const unsigned short hnum, const int dif)
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{
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struct sock *sk;
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const struct hlist_nulls_node *node;
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struct sock *result;
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int score, hiscore, matches = 0, reuseport = 0;
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u32 phash = 0;
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unsigned int hash = inet_lhashfn(net, hnum);
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struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
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rcu_read_lock();
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begin:
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result = NULL;
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hiscore = 0;
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sk_nulls_for_each(sk, node, &ilb->head) {
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score = compute_score(sk, net, hnum, daddr, dif);
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if (score > hiscore) {
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hiscore = score;
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result = sk;
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reuseport = sk->sk_reuseport;
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if (reuseport) {
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phash = inet6_ehashfn(net, daddr, hnum,
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saddr, sport);
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matches = 1;
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}
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} else if (score == hiscore && reuseport) {
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matches++;
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if (reciprocal_scale(phash, matches) == 0)
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result = sk;
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phash = next_pseudo_random32(phash);
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}
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}
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/*
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* if the nulls value we got at the end of this lookup is
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* not the expected one, we must restart lookup.
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* We probably met an item that was moved to another chain.
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*/
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if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
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goto begin;
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if (result) {
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if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
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result = NULL;
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else if (unlikely(compute_score(result, net, hnum, daddr,
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dif) < hiscore)) {
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sock_put(result);
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goto begin;
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}
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}
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rcu_read_unlock();
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return result;
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}
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EXPORT_SYMBOL_GPL(inet6_lookup_listener);
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struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
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const struct in6_addr *saddr, const __be16 sport,
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const struct in6_addr *daddr, const __be16 dport,
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const int dif)
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{
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struct sock *sk;
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local_bh_disable();
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sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif);
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local_bh_enable();
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return sk;
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}
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EXPORT_SYMBOL_GPL(inet6_lookup);
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static int __inet6_check_established(struct inet_timewait_death_row *death_row,
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struct sock *sk, const __u16 lport,
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struct inet_timewait_sock **twp)
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{
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struct inet_hashinfo *hinfo = death_row->hashinfo;
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struct inet_sock *inet = inet_sk(sk);
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const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr;
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const struct in6_addr *saddr = &sk->sk_v6_daddr;
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const int dif = sk->sk_bound_dev_if;
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const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
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struct net *net = sock_net(sk);
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const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
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inet->inet_dport);
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struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
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spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
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struct sock *sk2;
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const struct hlist_nulls_node *node;
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struct inet_timewait_sock *tw = NULL;
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int twrefcnt = 0;
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spin_lock(lock);
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sk_nulls_for_each(sk2, node, &head->chain) {
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if (sk2->sk_hash != hash)
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continue;
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if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) {
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if (sk2->sk_state == TCP_TIME_WAIT) {
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tw = inet_twsk(sk2);
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if (twsk_unique(sk, sk2, twp))
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break;
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}
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goto not_unique;
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}
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}
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/* Must record num and sport now. Otherwise we will see
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* in hash table socket with a funny identity.
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*/
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inet->inet_num = lport;
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inet->inet_sport = htons(lport);
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sk->sk_hash = hash;
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WARN_ON(!sk_unhashed(sk));
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__sk_nulls_add_node_rcu(sk, &head->chain);
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if (tw) {
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twrefcnt = inet_twsk_unhash(tw);
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NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
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}
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spin_unlock(lock);
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if (twrefcnt)
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inet_twsk_put(tw);
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
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if (twp) {
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*twp = tw;
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} else if (tw) {
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/* Silly. Should hash-dance instead... */
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inet_twsk_deschedule(tw);
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inet_twsk_put(tw);
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}
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return 0;
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not_unique:
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spin_unlock(lock);
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return -EADDRNOTAVAIL;
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}
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static u32 inet6_sk_port_offset(const struct sock *sk)
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{
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const struct inet_sock *inet = inet_sk(sk);
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return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
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sk->sk_v6_daddr.s6_addr32,
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inet->inet_dport);
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}
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int inet6_hash_connect(struct inet_timewait_death_row *death_row,
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struct sock *sk)
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{
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u32 port_offset = 0;
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if (!inet_sk(sk)->inet_num)
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port_offset = inet6_sk_port_offset(sk);
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return __inet_hash_connect(death_row, sk, port_offset,
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__inet6_check_established);
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}
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EXPORT_SYMBOL_GPL(inet6_hash_connect);
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