/* * 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/secure_seq.h> #include <net/ip.h> static u32 inet_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport, const __be32 faddr, const __be16 fport) { static u32 inet_ehash_secret __read_mostly; net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret)); return __inet_ehashfn(laddr, lport, faddr, fport, inet_ehash_secret + net_hash_mix(net)); } /* This function handles inet_sock, but also timewait and request sockets * for IPv4/IPv6. */ u32 sk_ehashfn(const struct sock *sk) { #if IS_ENABLED(CONFIG_IPV6) if (sk->sk_family == AF_INET6 && !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) return inet6_ehashfn(sock_net(sk), &sk->sk_v6_rcv_saddr, sk->sk_num, &sk->sk_v6_daddr, sk->sk_dport); #endif return inet_ehashfn(sock_net(sk), sk->sk_rcv_saddr, sk->sk_num, sk->sk_daddr, sk->sk_dport); } /* * 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 net *net, struct inet_bind_hashbucket *head, const unsigned short snum) { struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC); if (tb) { write_pnet(&tb->ib_net, net); tb->port = snum; tb->fastreuse = 0; tb->fastreuseport = 0; tb->num_owners = 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) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; atomic_inc(&hashinfo->bsockets); inet_sk(sk)->inet_num = snum; sk_add_bind_node(sk, &tb->owners); tb->num_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 sock *sk) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num, hashinfo->bhash_size); struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; struct inet_bind_bucket *tb; atomic_dec(&hashinfo->bsockets); spin_lock(&head->lock); tb = inet_csk(sk)->icsk_bind_hash; __sk_del_bind_node(sk); tb->num_owners--; inet_csk(sk)->icsk_bind_hash = NULL; inet_sk(sk)->inet_num = 0; inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); spin_unlock(&head->lock); } void inet_put_port(struct sock *sk) { local_bh_disable(); __inet_put_port(sk); local_bh_enable(); } EXPORT_SYMBOL(inet_put_port); int __inet_inherit_port(struct sock *sk, struct sock *child) { struct inet_hashinfo *table = sk->sk_prot->h.hashinfo; unsigned short port = inet_sk(child)->inet_num; const int bhash = inet_bhashfn(sock_net(sk), port, table->bhash_size); struct inet_bind_hashbucket *head = &table->bhash[bhash]; struct inet_bind_bucket *tb; spin_lock(&head->lock); tb = inet_csk(sk)->icsk_bind_hash; if (tb->port != port) { /* NOTE: using tproxy and redirecting skbs to a proxy * on a different listener port breaks the assumption * that the listener socket's icsk_bind_hash is the same * as that of the child socket. We have to look up or * create a new bind bucket for the child here. */ inet_bind_bucket_for_each(tb, &head->chain) { if (net_eq(ib_net(tb), sock_net(sk)) && tb->port == port) break; } if (!tb) { tb = inet_bind_bucket_create(table->bind_bucket_cachep, sock_net(sk), head, port); if (!tb) { spin_unlock(&head->lock); return -ENOMEM; } } } inet_bind_hash(child, tb, port); spin_unlock(&head->lock); return 0; } EXPORT_SYMBOL_GPL(__inet_inherit_port); static inline int compute_score(struct sock *sk, struct net *net, const unsigned short hnum, const __be32 daddr, const int dif) { int score = -1; struct inet_sock *inet = inet_sk(sk); if (net_eq(sock_net(sk), net) && inet->inet_num == hnum && !ipv6_only_sock(sk)) { __be32 rcv_saddr = inet->inet_rcv_saddr; score = sk->sk_family == PF_INET ? 2 : 1; if (rcv_saddr) { if (rcv_saddr != daddr) return -1; score += 4; } if (sk->sk_bound_dev_if) { if (sk->sk_bound_dev_if != dif) return -1; score += 4; } } return score; } /* * 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(struct net *net, struct inet_hashinfo *hashinfo, const __be32 saddr, __be16 sport, const __be32 daddr, const unsigned short hnum, const int dif) { struct sock *sk, *result; struct hlist_nulls_node *node; unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; int score, hiscore, matches = 0, reuseport = 0; u32 phash = 0; rcu_read_lock(); begin: result = NULL; hiscore = 0; sk_nulls_for_each_rcu(sk, node, &ilb->head) { score = compute_score(sk, net, hnum, daddr, dif); if (score > hiscore) { result = sk; hiscore = score; reuseport = sk->sk_reuseport; if (reuseport) { phash = inet_ehashfn(net, daddr, hnum, saddr, sport); matches = 1; } } else if (score == hiscore && reuseport) { matches++; if (reciprocal_scale(phash, matches) == 0) result = sk; phash = next_pseudo_random32(phash); } } /* * 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) != hash + LISTENING_NULLS_BASE) goto begin; if (result) { if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) result = NULL; else if (unlikely(compute_score(result, net, hnum, daddr, dif) < hiscore)) { sock_put(result); goto begin; } } rcu_read_unlock(); return result; } EXPORT_SYMBOL_GPL(__inet_lookup_listener); /* All sockets share common refcount, but have different destructors */ void sock_gen_put(struct sock *sk) { if (!atomic_dec_and_test(&sk->sk_refcnt)) return; if (sk->sk_state == TCP_TIME_WAIT) inet_twsk_free(inet_twsk(sk)); else if (sk->sk_state == TCP_NEW_SYN_RECV) reqsk_free(inet_reqsk(sk)); else sk_free(sk); } EXPORT_SYMBOL_GPL(sock_gen_put); void sock_edemux(struct sk_buff *skb) { sock_gen_put(skb->sk); } EXPORT_SYMBOL(sock_edemux); struct sock *__inet_lookup_established(struct net *net, 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_nulls_node *node; /* Optimize here for direct hit, only listening connections can * have wildcards anyways. */ unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport); unsigned int slot = hash & hashinfo->ehash_mask; struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; rcu_read_lock(); begin: sk_nulls_for_each_rcu(sk, node, &head->chain) { if (sk->sk_hash != hash) continue; if (likely(INET_MATCH(sk, net, acookie, saddr, daddr, ports, dif))) { if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) goto out; if (unlikely(!INET_MATCH(sk, net, acookie, saddr, daddr, ports, dif))) { sock_gen_put(sk); goto begin; } goto found; } } /* * 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 begin; out: sk = NULL; found: rcu_read_unlock(); return sk; } 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->inet_rcv_saddr; __be32 saddr = inet->inet_daddr; int dif = sk->sk_bound_dev_if; INET_ADDR_COOKIE(acookie, saddr, daddr); const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); struct net *net = sock_net(sk); unsigned int hash = inet_ehashfn(net, daddr, lport, saddr, inet->inet_dport); struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); spinlock_t *lock = inet_ehash_lockp(hinfo, hash); struct sock *sk2; const struct hlist_nulls_node *node; struct inet_timewait_sock *tw = NULL; int twrefcnt = 0; spin_lock(lock); sk_nulls_for_each(sk2, node, &head->chain) { if (sk2->sk_hash != hash) continue; if (likely(INET_MATCH(sk2, net, acookie, saddr, daddr, ports, dif))) { if (sk2->sk_state == TCP_TIME_WAIT) { tw = inet_twsk(sk2); if (twsk_unique(sk, sk2, twp)) break; } goto not_unique; } } /* Must record num and sport now. Otherwise we will see * in hash table socket with a funny identity. */ inet->inet_num = lport; inet->inet_sport = htons(lport); sk->sk_hash = hash; WARN_ON(!sk_unhashed(sk)); __sk_nulls_add_node_rcu(sk, &head->chain); if (tw) { twrefcnt = inet_twsk_unhash(tw); NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); } spin_unlock(lock); if (twrefcnt) inet_twsk_put(tw); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); if (twp) { *twp = tw; } else if (tw) { /* Silly. Should hash-dance instead... */ inet_twsk_deschedule(tw); inet_twsk_put(tw); } return 0; not_unique: spin_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->inet_rcv_saddr, inet->inet_daddr, inet->inet_dport); } int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; struct hlist_nulls_head *list; struct inet_ehash_bucket *head; spinlock_t *lock; int twrefcnt = 0; WARN_ON(!sk_unhashed(sk)); sk->sk_hash = sk_ehashfn(sk); head = inet_ehash_bucket(hashinfo, sk->sk_hash); list = &head->chain; lock = inet_ehash_lockp(hashinfo, sk->sk_hash); spin_lock(lock); __sk_nulls_add_node_rcu(sk, list); if (tw) { WARN_ON(sk->sk_hash != tw->tw_hash); twrefcnt = inet_twsk_unhash(tw); } spin_unlock(lock); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); return twrefcnt; } EXPORT_SYMBOL_GPL(__inet_hash_nolisten); int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; struct inet_listen_hashbucket *ilb; if (sk->sk_state != TCP_LISTEN) return __inet_hash_nolisten(sk, tw); WARN_ON(!sk_unhashed(sk)); ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; spin_lock(&ilb->lock); __sk_nulls_add_node_rcu(sk, &ilb->head); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); spin_unlock(&ilb->lock); return 0; } EXPORT_SYMBOL(__inet_hash); void inet_hash(struct sock *sk) { if (sk->sk_state != TCP_CLOSE) { local_bh_disable(); __inet_hash(sk, NULL); local_bh_enable(); } } EXPORT_SYMBOL_GPL(inet_hash); void inet_unhash(struct sock *sk) { struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; spinlock_t *lock; int done; if (sk_unhashed(sk)) return; if (sk->sk_state == TCP_LISTEN) lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock; else lock = inet_ehash_lockp(hashinfo, sk->sk_hash); spin_lock_bh(lock); done = __sk_nulls_del_node_init_rcu(sk); if (done) sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); spin_unlock_bh(lock); } EXPORT_SYMBOL_GPL(inet_unhash); int __inet_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk, u32 port_offset, int (*check_established)(struct inet_timewait_death_row *, struct sock *, __u16, struct inet_timewait_sock **)) { struct inet_hashinfo *hinfo = death_row->hashinfo; const unsigned short snum = inet_sk(sk)->inet_num; struct inet_bind_hashbucket *head; struct inet_bind_bucket *tb; int ret; struct net *net = sock_net(sk); int twrefcnt = 1; if (!snum) { int i, remaining, low, high, port; static u32 hint; u32 offset = hint + port_offset; struct inet_timewait_sock *tw = NULL; inet_get_local_port_range(net, &low, &high); remaining = (high - low) + 1; local_bh_disable(); for (i = 1; i <= remaining; i++) { port = low + (i + offset) % remaining; if (inet_is_local_reserved_port(net, port)) continue; head = &hinfo->bhash[inet_bhashfn(net, 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, &head->chain) { if (net_eq(ib_net(tb), net) && tb->port == port) { if (tb->fastreuse >= 0 || tb->fastreuseport >= 0) goto next_port; WARN_ON(hlist_empty(&tb->owners)); if (!check_established(death_row, sk, port, &tw)) goto ok; goto next_port; } } tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, net, head, port); if (!tb) { spin_unlock(&head->lock); break; } tb->fastreuse = -1; tb->fastreuseport = -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)->inet_sport = htons(port); twrefcnt += __inet_hash_nolisten(sk, tw); } if (tw) twrefcnt += inet_twsk_bind_unhash(tw, hinfo); spin_unlock(&head->lock); if (tw) { inet_twsk_deschedule(tw); while (twrefcnt) { twrefcnt--; inet_twsk_put(tw); } } ret = 0; goto out; } head = &hinfo->bhash[inet_bhashfn(net, 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) { __inet_hash_nolisten(sk, NULL); 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; } } /* * 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_sk_port_offset(sk), __inet_check_established); } EXPORT_SYMBOL_GPL(inet_hash_connect); void inet_hashinfo_init(struct inet_hashinfo *h) { int i; atomic_set(&h->bsockets, 0); for (i = 0; i < INET_LHTABLE_SIZE; i++) { spin_lock_init(&h->listening_hash[i].lock); INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head, i + LISTENING_NULLS_BASE); } } EXPORT_SYMBOL_GPL(inet_hashinfo_init);