[rds-devel] [PATCH 1/2] net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection.

[David Miller]

From: Sowmini Varadhan <sowmini.varadhan at oracle.com>
Date: Sat,  2 May 2015 07:55:08 -0400

> When running RDS over TCP, the active (client) side connects to the
> listening ("passive") side at the RDS_TCP_PORT.  After the connection
> is established, if the client side reboots (potentially without even
> sending a FIN) the server still has a TCP socket in the Established
> state.  If the server-side now gets a new SYN comes from the client
> with a different client port, TCP will create a new socket-pair, but
> the RDS layer will incorrectly pull up the old rds_connection (which
> is still associated with the stale t_sock and RDS socket state).
> 
> This patch corrects this behavior by having rds_tcp_accept_one()
> always create a new connection for an incoming TCP SYN.
> The rds and tcp state associated with the old socket-pair is cleaned
> up in rds_tcp_set_callbacks() (i.e., rds_conn_drop on the old
> connection)
> 
> Signed-off-by: Sowmini Varadhan <sowmini.varadhan at oracle.com>

I think adding 64K of data to this module just to solve this rare
issue is excessive.

Furthermore I don't see any locking protecting the hash table nor
the RDS socket linkage into that table.