--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff