Changes

The <code>TCP_REPAIR</code> socket option was added to the kernel 3.5 to help with C/R for TCP sockets.

The <code>TCP_REPAIR</code> socket option was added to the kernel 3.5 to help with C/R for TCP sockets.

When this option is used, a socket is switched into a special mode, in which any action performed on it

When this option is used, the socket is switched into a special mode, in which any action performed on it

does not result in anything defined by an appropriate protocol actions, but rather directly puts the socket

does not result in anything defined by an appropriate protocol actions, but rather directly puts the socket

into a state, in which the socket is expected to be at the end of the successfully finished operation.

into the state that the socket is expected to be in at the end of a successfully finished operation.

For example, calling <code>connect()</code> on a repaired socket just changes its state to <code>ESTABLISHED</code>,

For example, calling <code>connect()</code> on a repaired socket just changes its state to <code>ESTABLISHED</code>,

== States ==

== States ==

=== TCP_SYN_SENT ===

=== TCP_SYN_SENT ===

There is only one difference with TCP_ESTABLISHED, we have to restore a socket and disable the repair mode before calling <code>conenct()</code>. The kernel will send a one syn-sent packet with the same initial sequence number and sets the TCP_SYN_SENT state for the socket.

There is only one difference with TCP_ESTABLISHED, we have to restore a socket and disable the repair mode before calling <code>connect()</code>. The kernel will send a one syn-sent packet with the same initial sequence number and sets the TCP_SYN_SENT state for the socket.

=== Half-closed sockets ===

=== Half-closed sockets ===

* [[Simple TCP pair]]

* [[Simple TCP pair]]

* [[TCP repair TODO]]

* [[TCP repair TODO]]

== External links ==

== External links ==