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- /*
- * 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 <linux/vmalloc.h>
- #include <net/addrconf.h>
- #include <net/inet_connection_sock.h>
- #include <net/inet_hashtables.h>
- #include <net/secure_seq.h>
- #include <net/ip.h>
- #include <net/tcp.h>
- #include <net/sock_reuseport.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)
- {
- 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;
- 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(const 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 (unlikely(!tb)) {
- spin_unlock(&head->lock);
- return -ENOENT;
- }
- 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, bool exact_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 || exact_dif) {
- if (sk->sk_bound_dev_if != dif)
- return -1;
- score += 4;
- }
- if (sk->sk_incoming_cpu == raw_smp_processor_id())
- score++;
- }
- return score;
- }
- /*
- * 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.
- */
- /* called with rcu_read_lock() : No refcount taken on the socket */
- struct sock *__inet_lookup_listener(struct net *net,
- struct inet_hashinfo *hashinfo,
- struct sk_buff *skb, int doff,
- const __be32 saddr, __be16 sport,
- const __be32 daddr, const unsigned short hnum,
- const int dif)
- {
- unsigned int hash = inet_lhashfn(net, hnum);
- struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
- int score, hiscore = 0, matches = 0, reuseport = 0;
- bool exact_dif = inet_exact_dif_match(net, skb);
- struct sock *sk, *result = NULL;
- u32 phash = 0;
- sk_for_each_rcu(sk, &ilb->head) {
- score = compute_score(sk, net, hnum, daddr, dif, exact_dif);
- if (score > hiscore) {
- reuseport = sk->sk_reuseport;
- if (reuseport) {
- phash = inet_ehashfn(net, daddr, hnum,
- saddr, sport);
- result = reuseport_select_sock(sk, phash,
- skb, doff);
- if (result)
- return result;
- matches = 1;
- }
- result = sk;
- hiscore = score;
- } else if (score == hiscore && reuseport) {
- matches++;
- if (reciprocal_scale(phash, matches) == 0)
- result = sk;
- phash = next_pseudo_random32(phash);
- }
- }
- 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];
- 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:
- 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;
- 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) {
- sk_nulls_del_node_init_rcu((struct sock *)tw);
- __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED);
- }
- spin_unlock(lock);
- 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_put(tw);
- }
- return 0;
- not_unique:
- spin_unlock(lock);
- return -EADDRNOTAVAIL;
- }
- static 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);
- }
- /* insert a socket into ehash, and eventually remove another one
- * (The another one can be a SYN_RECV or TIMEWAIT
- */
- bool inet_ehash_insert(struct sock *sk, struct sock *osk)
- {
- struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
- struct hlist_nulls_head *list;
- struct inet_ehash_bucket *head;
- spinlock_t *lock;
- bool ret = true;
- WARN_ON_ONCE(!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);
- if (osk) {
- WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
- ret = sk_nulls_del_node_init_rcu(osk);
- }
- if (ret)
- __sk_nulls_add_node_rcu(sk, list);
- spin_unlock(lock);
- return ret;
- }
- bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
- {
- bool ok = inet_ehash_insert(sk, osk);
- if (ok) {
- sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
- } else {
- percpu_counter_inc(sk->sk_prot->orphan_count);
- sk->sk_state = TCP_CLOSE;
- sock_set_flag(sk, SOCK_DEAD);
- inet_csk_destroy_sock(sk);
- }
- return ok;
- }
- EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
- static int inet_reuseport_add_sock(struct sock *sk,
- struct inet_listen_hashbucket *ilb,
- int (*saddr_same)(const struct sock *sk1,
- const struct sock *sk2,
- bool match_wildcard))
- {
- struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash;
- struct sock *sk2;
- kuid_t uid = sock_i_uid(sk);
- sk_for_each_rcu(sk2, &ilb->head) {
- if (sk2 != sk &&
- sk2->sk_family == sk->sk_family &&
- ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
- sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
- inet_csk(sk2)->icsk_bind_hash == tb &&
- sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
- saddr_same(sk, sk2, false))
- return reuseport_add_sock(sk, sk2);
- }
- return reuseport_alloc(sk);
- }
- int __inet_hash(struct sock *sk, struct sock *osk,
- int (*saddr_same)(const struct sock *sk1,
- const struct sock *sk2,
- bool match_wildcard))
- {
- struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
- struct inet_listen_hashbucket *ilb;
- int err = 0;
- if (sk->sk_state != TCP_LISTEN) {
- inet_ehash_nolisten(sk, osk);
- return 0;
- }
- WARN_ON(!sk_unhashed(sk));
- ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
- spin_lock(&ilb->lock);
- if (sk->sk_reuseport) {
- err = inet_reuseport_add_sock(sk, ilb, saddr_same);
- if (err)
- goto unlock;
- }
- if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
- sk->sk_family == AF_INET6)
- hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
- else
- hlist_add_head_rcu(&sk->sk_node, &ilb->head);
- sock_set_flag(sk, SOCK_RCU_FREE);
- sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
- unlock:
- spin_unlock(&ilb->lock);
- return err;
- }
- EXPORT_SYMBOL(__inet_hash);
- int inet_hash(struct sock *sk)
- {
- int err = 0;
- if (sk->sk_state != TCP_CLOSE) {
- local_bh_disable();
- err = __inet_hash(sk, NULL, ipv4_rcv_saddr_equal);
- local_bh_enable();
- }
- return err;
- }
- EXPORT_SYMBOL_GPL(inet_hash);
- void inet_unhash(struct sock *sk)
- {
- struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
- spinlock_t *lock;
- bool listener = false;
- int done;
- if (sk_unhashed(sk))
- return;
- if (sk->sk_state == TCP_LISTEN) {
- lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
- listener = true;
- } else {
- lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
- }
- spin_lock_bh(lock);
- if (rcu_access_pointer(sk->sk_reuseport_cb))
- reuseport_detach_sock(sk);
- if (listener)
- done = __sk_del_node_init(sk);
- else
- 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;
- struct inet_timewait_sock *tw = NULL;
- struct inet_bind_hashbucket *head;
- int port = inet_sk(sk)->inet_num;
- struct net *net = sock_net(sk);
- struct inet_bind_bucket *tb;
- u32 remaining, offset;
- int ret, i, low, high;
- static u32 hint;
- if (port) {
- head = &hinfo->bhash[inet_bhashfn(net, port,
- 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_ehash_nolisten(sk, NULL);
- spin_unlock_bh(&head->lock);
- return 0;
- }
- spin_unlock(&head->lock);
- /* No definite answer... Walk to established hash table */
- ret = check_established(death_row, sk, port, NULL);
- local_bh_enable();
- return ret;
- }
- inet_get_local_port_range(net, &low, &high);
- high++; /* [32768, 60999] -> [32768, 61000[ */
- remaining = high - low;
- if (likely(remaining > 1))
- remaining &= ~1U;
- offset = (hint + port_offset) % remaining;
- /* In first pass we try ports of @low parity.
- * inet_csk_get_port() does the opposite choice.
- */
- offset &= ~1U;
- other_parity_scan:
- port = low + offset;
- for (i = 0; i < remaining; i += 2, port += 2) {
- if (unlikely(port >= high))
- port -= remaining;
- if (inet_is_local_reserved_port(net, port))
- continue;
- head = &hinfo->bhash[inet_bhashfn(net, port,
- hinfo->bhash_size)];
- spin_lock_bh(&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_bh(&head->lock);
- return -ENOMEM;
- }
- tb->fastreuse = -1;
- tb->fastreuseport = -1;
- goto ok;
- next_port:
- spin_unlock_bh(&head->lock);
- cond_resched();
- }
- offset++;
- if ((offset & 1) && remaining > 1)
- goto other_parity_scan;
- return -EADDRNOTAVAIL;
- ok:
- hint += i + 2;
- /* 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);
- inet_ehash_nolisten(sk, (struct sock *)tw);
- }
- if (tw)
- inet_twsk_bind_unhash(tw, hinfo);
- spin_unlock(&head->lock);
- if (tw)
- inet_twsk_deschedule_put(tw);
- local_bh_enable();
- return 0;
- }
- /*
- * Bind a port for a connect operation and hash it.
- */
- int inet_hash_connect(struct inet_timewait_death_row *death_row,
- struct sock *sk)
- {
- u32 port_offset = 0;
- if (!inet_sk(sk)->inet_num)
- port_offset = inet_sk_port_offset(sk);
- return __inet_hash_connect(death_row, sk, port_offset,
- __inet_check_established);
- }
- EXPORT_SYMBOL_GPL(inet_hash_connect);
- void inet_hashinfo_init(struct inet_hashinfo *h)
- {
- int i;
- for (i = 0; i < INET_LHTABLE_SIZE; i++) {
- spin_lock_init(&h->listening_hash[i].lock);
- INIT_HLIST_HEAD(&h->listening_hash[i].head);
- }
- }
- EXPORT_SYMBOL_GPL(inet_hashinfo_init);
- int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
- {
- unsigned int locksz = sizeof(spinlock_t);
- unsigned int i, nblocks = 1;
- if (locksz != 0) {
- /* allocate 2 cache lines or at least one spinlock per cpu */
- nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
- nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
- /* no more locks than number of hash buckets */
- nblocks = min(nblocks, hashinfo->ehash_mask + 1);
- hashinfo->ehash_locks = kmalloc_array(nblocks, locksz,
- GFP_KERNEL | __GFP_NOWARN);
- if (!hashinfo->ehash_locks)
- hashinfo->ehash_locks = vmalloc(nblocks * locksz);
- if (!hashinfo->ehash_locks)
- return -ENOMEM;
- for (i = 0; i < nblocks; i++)
- spin_lock_init(&hashinfo->ehash_locks[i]);
- }
- hashinfo->ehash_locks_mask = nblocks - 1;
- return 0;
- }
- EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);
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