Commit 6bd8feda authored Oct 25, 2007 by Lon Hohberger Committed by David Teigland Jan 29, 2008

dlm: bind connections from known local address when using TCP



A common problem occurs when multiple IP addresses within the same
subnet are assigned to the same NIC.  If we make a connection attempt to
another address on the same subnet as one of those addresses, the
connection attempt will not necessarily be routed from the address we
want.

In the case of the DLM, the other nodes will quickly drop the connection
attempt, causing problems.

This patch makes the DLM bind to the local address it acquired from the
cluster manager when using TCP prior to making a connection, obviating
the need for administrators to "fix" their systems or use clever routing
tricks.

Signed-off-by: Lon Hohberger <lhh@redhat.com>
Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

parent 0ba6c33b

fs/dlm/lowcomms.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -864,7 +864,7 @@ static void sctp_init_assoc(struct connection *con)
		static void tcp_connect_to_sock(struct connection *con)
		{
		int result = -EHOSTUNREACH;
		struct sockaddr_storage saddr;
		struct sockaddr_storage saddr, src_addr;
		int addr_len;
		struct socket *sock;

		@@ -898,6 +898,17 @@ static void tcp_connect_to_sock(struct connection *con)
		con->connect_action = tcp_connect_to_sock;
		add_sock(sock, con);

		/* Bind to our cluster-known address connecting to avoid
		routing problems */
		memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
		make_sockaddr(&src_addr, 0, &addr_len);
		result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
		addr_len);
		if (result < 0) {
		log_print("could not bind for connect: %d", result);
		/* This may not indicate a critical error */
		}

		make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);

		log_print("connecting to %d", con->nodeid);

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