fs: dlm: introduce generic listen

This patch combines each transport layer listen functionality into one
listen function. Per transport layer differences are provided by
additional callbacks in dlm_proto_ops.

This patch drops silently sock_set_keepalive() for listen tcp sockets
only. This socket option is not set at connecting sockets, I also don't
see the sense of set keepalive for sockets which are created by accept()
only.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

Author: Alexander Aring

fs/dlm/lowcomms.c

@@ -143,6 +143,13 @@ struct dlm_node_addr {
 };
 
 struct dlm_proto_ops {
+	const char *name;
+	int proto;
+
+	int (*listen_validate)(void);
+	void (*listen_sockopts)(struct socket *sock);
+	int (*listen_bind)(struct socket *sock);
+
 	/* What to do to connect */
 	void (*connect_action)(struct connection *con);
 	/* What to do to shutdown */
@@ -1327,59 +1334,6 @@ static void tcp_connect_to_sock(struct connection *con)
 	return;
 }
 
-/* On error caller must run dlm_close_sock() for the
- * listen connection socket.
- */
-static int tcp_create_listen_sock(struct listen_connection *con,
-				  struct sockaddr_storage *saddr)
-{
-	struct socket *sock = NULL;
-	int result = 0;
-	int addr_len;
-
-	if (dlm_local_addr[0]->ss_family == AF_INET)
-		addr_len = sizeof(struct sockaddr_in);
-	else
-		addr_len = sizeof(struct sockaddr_in6);
-
-	/* Create a socket to communicate with */
-	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
-				  SOCK_STREAM, IPPROTO_TCP, &sock);
-	if (result < 0) {
-		log_print("Can't create listening comms socket");
-		goto create_out;
-	}
-
-	sock_set_mark(sock->sk, dlm_config.ci_mark);
-
-	/* Turn off Nagle's algorithm */
-	tcp_sock_set_nodelay(sock->sk);
-
-	sock_set_reuseaddr(sock->sk);
-
-	add_listen_sock(sock, con);
-
-	/* Bind to our port */
-	make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
-	result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
-	if (result < 0) {
-		log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
-		goto create_out;
-	}
-	sock_set_keepalive(sock->sk);
-
-	result = sock->ops->listen(sock, 5);
-	if (result < 0) {
-		log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
-		goto create_out;
-	}
-
-	return 0;
-
-create_out:
-	return result;
-}
-
 /* Get local addresses */
 static void init_local(void)
 {
@@ -1406,63 +1360,6 @@ static void deinit_local(void)
 		kfree(dlm_local_addr[i]);
 }
 
-/* Initialise SCTP socket and bind to all interfaces
- * On error caller must run dlm_close_sock() for the
- * listen connection socket.
- */
-static int sctp_listen_for_all(struct listen_connection *con)
-{
-	struct socket *sock = NULL;
-	int result = -EINVAL;
-
-	log_print("Using SCTP for communications");
-
-	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
-				  SOCK_STREAM, IPPROTO_SCTP, &sock);
-	if (result < 0) {
-		log_print("Can't create comms socket, check SCTP is loaded");
-		goto out;
-	}
-
-	sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
-	sock_set_mark(sock->sk, dlm_config.ci_mark);
-	sctp_sock_set_nodelay(sock->sk);
-
-	add_listen_sock(sock, con);
-
-	/* Bind to all addresses. */
-	result = sctp_bind_addrs(con->sock, dlm_config.ci_tcp_port);
-	if (result < 0)
-		goto out;
-
-	result = sock->ops->listen(sock, 5);
-	if (result < 0) {
-		log_print("Can't set socket listening");
-		goto out;
-	}
-
-	return 0;
-
-out:
-	return result;
-}
-
-static int tcp_listen_for_all(void)
-{
-	/* We don't support multi-homed hosts */
-	if (dlm_local_count > 1) {
-		log_print("TCP protocol can't handle multi-homed hosts, "
-			  "try SCTP");
-		return -EINVAL;
-	}
-
-	log_print("Using TCP for communications");
-
-	return tcp_create_listen_sock(&listen_con, dlm_local_addr[0]);
-}
-
-
-
 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
 						     gfp_t allocation)
 {
@@ -1959,13 +1856,112 @@ void dlm_lowcomms_stop(void)
 	dlm_proto_ops = NULL;
 }
 
+static int dlm_listen_for_all(void)
+{
+	struct socket *sock;
+	int result;
+
+	log_print("Using %s for communications",
+		  dlm_proto_ops->name);
+
+	if (dlm_proto_ops->listen_validate) {
+		result = dlm_proto_ops->listen_validate();
+		if (result < 0)
+			return result;
+	}
+
+	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
+				  SOCK_STREAM, dlm_proto_ops->proto, &sock);
+	if (result < 0) {
+		log_print("Can't create comms socket, check SCTP is loaded");
+		goto out;
+	}
+
+	sock_set_mark(sock->sk, dlm_config.ci_mark);
+	dlm_proto_ops->listen_sockopts(sock);
+
+	result = dlm_proto_ops->listen_bind(sock);
+	if (result < 0)
+		goto out;
+
+	save_listen_callbacks(sock);
+	add_listen_sock(sock, &listen_con);
+
+	INIT_WORK(&listen_con.rwork, process_listen_recv_socket);
+	result = sock->ops->listen(sock, 5);
+	if (result < 0) {
+		dlm_close_sock(&listen_con.sock);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	sock_release(sock);
+	return result;
+}
+
+static int dlm_tcp_listen_validate(void)
+{
+	/* We don't support multi-homed hosts */
+	if (dlm_local_count > 1) {
+		log_print("TCP protocol can't handle multi-homed hosts, try SCTP");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void dlm_tcp_sockopts(struct socket *sock)
+{
+	/* Turn off Nagle's algorithm */
+	tcp_sock_set_nodelay(sock->sk);
+}
+
+static void dlm_tcp_listen_sockopts(struct socket *sock)
+{
+	dlm_tcp_sockopts(sock);
+	sock_set_reuseaddr(sock->sk);
+}
+
+static int dlm_tcp_listen_bind(struct socket *sock)
+{
+	int addr_len;
+
+	/* Bind to our port */
+	make_sockaddr(dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
+	return sock->ops->bind(sock, (struct sockaddr *)dlm_local_addr[0],
+			       addr_len);
+}
+
 static const struct dlm_proto_ops dlm_tcp_ops = {
+	.name = "TCP",
+	.proto = IPPROTO_TCP,
+	.listen_validate = dlm_tcp_listen_validate,
+	.listen_sockopts = dlm_tcp_listen_sockopts,
+	.listen_bind = dlm_tcp_listen_bind,
 	.connect_action = tcp_connect_to_sock,
 	.shutdown_action = dlm_tcp_shutdown,
 	.eof_condition = tcp_eof_condition,
 };
 
+static int dlm_sctp_bind_listen(struct socket *sock)
+{
+	return sctp_bind_addrs(sock, dlm_config.ci_tcp_port);
+}
+
+static void dlm_sctp_sockopts(struct socket *sock)
+{
+	/* Turn off Nagle's algorithm */
+	sctp_sock_set_nodelay(sock->sk);
+	sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
+}
+
 static const struct dlm_proto_ops dlm_sctp_ops = {
+	.name = "SCTP",
+	.proto = IPPROTO_SCTP,
+	.listen_sockopts = dlm_sctp_sockopts,
+	.listen_bind = dlm_sctp_bind_listen,
 	.connect_action = sctp_connect_to_sock,
 };
 
@@ -1996,24 +1992,26 @@ int dlm_lowcomms_start(void)
 	switch (dlm_config.ci_protocol) {
 	case DLM_PROTO_TCP:
 		dlm_proto_ops = &dlm_tcp_ops;
-		error = tcp_listen_for_all();
 		break;
 	case DLM_PROTO_SCTP:
 		dlm_proto_ops = &dlm_sctp_ops;
-		error = sctp_listen_for_all(&listen_con);
 		break;
 	default:
 		log_print("Invalid protocol identifier %d set",
 			  dlm_config.ci_protocol);
 		error = -EINVAL;
-		break;
+		goto fail_proto_ops;
 	}
+
+	error = dlm_listen_for_all();
 	if (error)
-		goto fail_unlisten;
+		goto fail_listen;
 
 	return 0;
 
-fail_unlisten:
+fail_listen:
+	dlm_proto_ops = NULL;
+fail_proto_ops:
 	dlm_allow_conn = 0;
 	dlm_close_sock(&listen_con.sock);
 	work_stop();