1 files changed, 584 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
new file mode 100644
index 00000000..984ec656
--- /dev/null
+++ b/net/ipv4/inet_hashtables.c
@@ -0,0 +1,584 @@
+/*
+ * 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>
+
+/*
+ * 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 != NULL) {
+		write_pnet(&tb->ib_net, hold_net(net));
+		tb->port      = snum;
+		tb->fastreuse = 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);
+		release_net(ib_net(tb));
+		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. */
+		struct hlist_node *node;
+		inet_bind_bucket_for_each(tb, node, &head->chain) {
+			if (net_eq(ib_net(tb), sock_net(sk)) &&
+			    tb->port == port)
+				break;
+		}
+		if (!node) {
+			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 ? 1 : 0;
+		if (rcv_saddr) {
+			if (rcv_saddr != daddr)
+				return -1;
+			score += 2;
+		}
+		if (sk->sk_bound_dev_if) {
+			if (sk->sk_bound_dev_if != dif)
+				return -1;
+			score += 2;
+		}
+	}
+	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 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;
+
+	rcu_read_lock();
+begin:
+	result = NULL;
+	hiscore = -1;
+	sk_nulls_for_each_rcu(sk, node, &ilb->head) {
+		score = compute_score(sk, net, hnum, daddr, dif);
+		if (score > hiscore) {
+			result = sk;
+			hiscore = score;
+		}
+	}
+	/*
+	 * 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);
+
+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 (INET_MATCH(sk, net, hash, acookie,
+					saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
+				goto begintw;
+			if (unlikely(!INET_MATCH(sk, net, hash, acookie,
+				saddr, daddr, ports, dif))) {
+				sock_put(sk);
+				goto begin;
+			}
+			goto out;
+		}
+	}
+	/*
+	 * 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;
+
+begintw:
+	/* Must check for a TIME_WAIT'er before going to listener hash. */
+	sk_nulls_for_each_rcu(sk, node, &head->twchain) {
+		if (INET_TW_MATCH(sk, net, hash, acookie,
+					saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
+				sk = NULL;
+				goto out;
+			}
+			if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
+				 saddr, daddr, ports, dif))) {
+				sock_put(sk);
+				goto begintw;
+			}
+			goto out;
+		}
+	}
+	/*
+	 * 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 begintw;
+	sk = NULL;
+out:
+	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;
+	int twrefcnt = 0;
+
+	spin_lock(lock);
+
+	/* Check TIME-WAIT sockets first. */
+	sk_nulls_for_each(sk2, node, &head->twchain) {
+		tw = inet_twsk(sk2);
+
+		if (INET_TW_MATCH(sk2, net, hash, acookie,
+					saddr, daddr, ports, dif)) {
+			if (twsk_unique(sk, sk2, twp))
+				goto unique;
+			else
+				goto not_unique;
+		}
+	}
+	tw = NULL;
+
+	/* And established part... */
+	sk_nulls_for_each(sk2, node, &head->chain) {
+		if (INET_MATCH(sk2, net, hash, acookie,
+					saddr, daddr, ports, dif))
+			goto not_unique;
+	}
+
+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, death_row);
+
+		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;
+	spinlock_t *lock;
+	struct inet_ehash_bucket *head;
+	int twrefcnt = 0;
+
+	WARN_ON(!sk_unhashed(sk));
+
+	sk->sk_hash = inet_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);
+
+static void __inet_hash(struct sock *sk)
+{
+	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_listen_hashbucket *ilb;
+
+	if (sk->sk_state != TCP_LISTEN) {
+		__inet_hash_nolisten(sk, NULL);
+		return;
+	}
+
+	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);
+}
+
+void inet_hash(struct sock *sk)
+{
+	if (sk->sk_state != TCP_CLOSE) {
+		local_bh_disable();
+		__inet_hash(sk);
+		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 **),
+		int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
+{
+	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 hlist_node *node;
+		struct inet_timewait_sock *tw = NULL;
+
+		inet_get_local_port_range(&low, &high);
+		remaining = (high - low) + 1;
+
+		local_bh_disable();
+		for (i = 1; i <= remaining; i++) {
+			port = low + (i + offset) % remaining;
+			if (inet_is_reserved_local_port(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, node, &head->chain) {
+				if (net_eq(ib_net(tb), net) &&
+				    tb->port == port) {
+					if (tb->fastreuse >= 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;
+			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 += hash(sk, tw);
+		}
+		if (tw)
+			twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
+		spin_unlock(&head->lock);
+
+		if (tw) {
+			inet_twsk_deschedule(tw, death_row);
+			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) {
+		hash(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, __inet_hash_nolisten);
+}
+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);