From dca43c75e7e545694a9dd6288553f55c53e2a3a3 Mon Sep 17 00:00:00 2001 From: Jerry Chu Date: Fri, 27 Aug 2010 19:13:28 +0000 Subject: tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu Signed-off-by: David S. Miller --- include/net/inet_connection_sock.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/inet_connection_sock.h') diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index b6d3b55da19b..e4f494b42e06 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -125,6 +125,7 @@ struct inet_connection_sock { int probe_size; } icsk_mtup; u32 icsk_ca_priv[16]; + u32 icsk_user_timeout; #define ICSK_CA_PRIV_SIZE (16 * sizeof(u32)) }; -- cgit v1.2.1