sctp: apply rhashtable api to send/recv path

apply lookup apis to two functions, for __sctp_endpoint_lookup_assoc
and __sctp_lookup_association, it's invoked in the protection of sock
lock, it will be safe, but sctp_lookup_association need to call
rcu_read_lock() and to detect the t->dead to protect it.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: lxin

net/sctp/associola.c

@@ -383,6 +383,7 @@ void sctp_association_free(struct sctp_association *asoc)
 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
 		transport = list_entry(pos, struct sctp_transport, transports);
 		list_del_rcu(pos);
+		sctp_unhash_transport(transport);
 		sctp_transport_free(transport);
 	}
 
@@ -500,6 +501,8 @@ void sctp_assoc_rm_peer(struct sctp_association *asoc,
 
 	/* Remove this peer from the list. */
 	list_del_rcu(&peer->transports);
+	/* Remove this peer from the transport hashtable */
+	sctp_unhash_transport(peer);
 
 	/* Get the first transport of asoc. */
 	pos = asoc->peer.transport_addr_list.next;
@@ -699,6 +702,8 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 	/* Attach the remote transport to our asoc.  */
 	list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list);
 	asoc->peer.transport_count++;
+	/* Add this peer into the transport hashtable */
+	sctp_hash_transport(peer);
 
 	/* If we do not yet have a primary path, set one.  */
 	if (!asoc->peer.primary_path) {

net/sctp/endpointola.c

@@ -314,21 +314,16 @@ struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 }
 
 /* Find the association that goes with this chunk.
- * We do a linear search of the associations for this endpoint.
- * We return the matching transport address too.
+ * We lookup the transport from hashtable at first, then get association
+ * through t->assoc.
  */
 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 	const struct sctp_endpoint *ep,
 	const union sctp_addr *paddr,
 	struct sctp_transport **transport)
 {
 	struct sctp_association *asoc = NULL;
-	struct sctp_association *tmp;
-	struct sctp_transport *t = NULL;
-	struct sctp_hashbucket *head;
-	struct sctp_ep_common *epb;
-	int hash;
-	int rport;
+	struct sctp_transport *t;
 
 	*transport = NULL;
 
@@ -337,26 +332,12 @@ static struct sctp_association *__sctp_endpoint_lookup_assoc(
 	 */
 	if (!ep->base.bind_addr.port)
 		goto out;
+	t = sctp_epaddr_lookup_transport(ep, paddr);
+	if (!t || t->asoc->temp)
+		goto out;
 
-	rport = ntohs(paddr->v4.sin_port);
-
-	hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
-				 rport);
-	head = &sctp_assoc_hashtable[hash];
-	read_lock(&head->lock);
-	sctp_for_each_hentry(epb, &head->chain) {
-		tmp = sctp_assoc(epb);
-		if (tmp->ep != ep || rport != tmp->peer.port)
-			continue;
-
-		t = sctp_assoc_lookup_paddr(tmp, paddr);
-		if (t) {
-			asoc = tmp;
-			*transport = t;
-			break;
-		}
-	}
-	read_unlock(&head->lock);
+	*transport = t;
+	asoc = t->asoc;
 out:
 	return asoc;
 }

net/sctp/input.c

@@ -981,38 +981,19 @@ static struct sctp_association *__sctp_lookup_association(
 					const union sctp_addr *peer,
 					struct sctp_transport **pt)
 {
-	struct sctp_hashbucket *head;
-	struct sctp_ep_common *epb;
-	struct sctp_association *asoc;
-	struct sctp_transport *transport;
-	int hash;
+	struct sctp_transport *t;
 
-	/* Optimize here for direct hit, only listening connections can
-	 * have wildcards anyways.
-	 */
-	hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port),
-				 ntohs(peer->v4.sin_port));
-	head = &sctp_assoc_hashtable[hash];
-	read_lock(&head->lock);
-	sctp_for_each_hentry(epb, &head->chain) {
-		asoc = sctp_assoc(epb);
-		transport = sctp_assoc_is_match(asoc, net, local, peer);
-		if (transport)
-			goto hit;
-	}
+	t = sctp_addrs_lookup_transport(net, local, peer);
+	if (!t || t->dead || t->asoc->temp)
+		return NULL;
 
-	read_unlock(&head->lock);
+	sctp_association_hold(t->asoc);
+	*pt = t;
 
-	return NULL;
-
-hit:
-	*pt = transport;
-	sctp_association_hold(asoc);
-	read_unlock(&head->lock);
-	return asoc;
+	return t->asoc;
 }
 
-/* Look up an association. BH-safe. */
+/* Look up an association. protected by RCU read lock */
 static
 struct sctp_association *sctp_lookup_association(struct net *net,
 						 const union sctp_addr *laddr,
@@ -1021,9 +1002,9 @@ struct sctp_association *sctp_lookup_association(struct net *net,
 {
 	struct sctp_association *asoc;
 
-	local_bh_disable();
+	rcu_read_lock();
 	asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
-	local_bh_enable();
+	rcu_read_unlock();
 
 	return asoc;
 }

net/sctp/protocol.c

@@ -1467,6 +1467,9 @@ static __init int sctp_init(void)
 		INIT_HLIST_HEAD(&sctp_port_hashtable[i].chain);
 	}
 
+	if (sctp_transport_hashtable_init())
+		goto err_thash_alloc;
+
 	pr_info("Hash tables configured (established %d bind %d)\n",
 		sctp_assoc_hashsize, sctp_port_hashsize);
 
@@ -1521,6 +1524,8 @@ static __init int sctp_init(void)
 		   get_order(sctp_port_hashsize *
 			     sizeof(struct sctp_bind_hashbucket)));
 err_bhash_alloc:
+	sctp_transport_hashtable_destroy();
+err_thash_alloc:
 	kfree(sctp_ep_hashtable);
 err_ehash_alloc:
 	free_pages((unsigned long)sctp_assoc_hashtable,
@@ -1567,6 +1572,7 @@ static __exit void sctp_exit(void)
 	free_pages((unsigned long)sctp_port_hashtable,
 		   get_order(sctp_port_hashsize *
 			     sizeof(struct sctp_bind_hashbucket)));
+	sctp_transport_hashtable_destroy();
 
 	percpu_counter_destroy(&sctp_sockets_allocated);