[INET]: Generalise tcp_v4_hash_connect

Renaming it to inet_hash_connect, making it possible to ditch
dccp_v4_hash_connect and share the same code with TCP instead.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 178 insertions, 0 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index e8d29fe736d2..33228115cda4 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -15,12 +15,14 @@
 
 #include <linux/config.h>
 #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/ip.h>
 
 /*
  * Allocate and initialize a new local port bind bucket.
@@ -163,3 +165,179 @@ struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 dad
 }
 
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
+
+/* 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);
+	u32 daddr = inet->rcv_saddr;
+	u32 saddr = inet->daddr;
+	int dif = sk->sk_bound_dev_if;
+	INET_ADDR_COOKIE(acookie, saddr, daddr)
+	const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
+	unsigned int hash = inet_ehashfn(daddr, lport, saddr, inet->dport);
+	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
+	struct sock *sk2;
+	const struct hlist_node *node;
+	struct inet_timewait_sock *tw;
+
+	prefetch(head->chain.first);
+	write_lock(&head->lock);
+
+	/* Check TIME-WAIT sockets first. */
+	sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
+		tw = inet_twsk(sk2);
+
+		if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) {
+			if (twsk_unique(sk, sk2, twp))
+				goto unique;
+			else
+				goto not_unique;
+		}
+	}
+	tw = NULL;
+
+	/* And established part... */
+	sk_for_each(sk2, node, &head->chain) {
+		if (INET_MATCH(sk2, 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->num = lport;
+	inet->sport = htons(lport);
+	sk->sk_hash = hash;
+	BUG_TRAP(sk_unhashed(sk));
+	__sk_add_node(sk, &head->chain);
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(&head->lock);
+
+	if (twp) {
+		*twp = tw;
+		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+	} else if (tw) {
+		/* Silly. Should hash-dance instead... */
+		inet_twsk_deschedule(tw, death_row);
+		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+
+		inet_twsk_put(tw);
+	}
+
+	return 0;
+
+not_unique:
+	write_unlock(&head->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->rcv_saddr, inet->daddr, 
+					  inet->dport);
+}
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+int inet_hash_connect(struct inet_timewait_death_row *death_row,
+		      struct sock *sk)
+{
+	struct inet_hashinfo *hinfo = death_row->hashinfo;
+	const unsigned short snum = inet_sk(sk)->num;
+ 	struct inet_bind_hashbucket *head;
+ 	struct inet_bind_bucket *tb;
+	int ret;
+
+ 	if (!snum) {
+ 		int low = sysctl_local_port_range[0];
+ 		int high = sysctl_local_port_range[1];
+		int range = high - low;
+ 		int i;
+		int port;
+		static u32 hint;
+		u32 offset = hint + inet_sk_port_offset(sk);
+		struct hlist_node *node;
+ 		struct inet_timewait_sock *tw = NULL;
+
+ 		local_bh_disable();
+		for (i = 1; i <= range; i++) {
+			port = low + (i + offset) % range;
+ 			head = &hinfo->bhash[inet_bhashfn(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 (tb->port == port) {
+ 					BUG_TRAP(!hlist_empty(&tb->owners));
+ 					if (tb->fastreuse >= 0)
+ 						goto next_port;
+ 					if (!__inet_check_established(death_row,
+								      sk, port,
+								      &tw))
+ 						goto ok;
+ 					goto next_port;
+ 				}
+ 			}
+
+ 			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, 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)->sport = htons(port);
+ 			__inet_hash(hinfo, sk, 0);
+ 		}
+ 		spin_unlock(&head->lock);
+
+ 		if (tw) {
+ 			inet_twsk_deschedule(tw, death_row);;
+ 			inet_twsk_put(tw);
+ 		}
+
+		ret = 0;
+		goto out;
+ 	}
+
+ 	head = &hinfo->bhash[inet_bhashfn(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(hinfo, sk, 0);
+		spin_unlock_bh(&head->lock);
+		return 0;
+	} else {
+		spin_unlock(&head->lock);
+		/* No definite answer... Walk to established hash table */
+		ret = __inet_check_established(death_row, sk, snum, NULL);
+out:
+		local_bh_enable();
+		return ret;
+	}
+}
+
+EXPORT_SYMBOL_GPL(inet_hash_connect);