From f711a6ae062caeee46067b2f2f12ffda319ae73c Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Tue, 5 May 2015 15:20:51 -0400 Subject: net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection. 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 esablished 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 via the rds_tcp_state_change() callback which would typically be invoked in most cases when the client-TCP sends a FIN on TCP restart, triggering a transition to CLOSE_WAIT state. In the rarer event of client death without a FIN, TCP_KEEPALIVE probes on the socket will detect the stale socket, and the TCP transition to CLOSE state will trigger the RDS state cleanup. Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller --- net/rds/connection.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/rds/connection.c') diff --git a/net/rds/connection.c b/net/rds/connection.c index 14f041398ca1..60f0cd6ed15f 100644 --- a/net/rds/connection.c +++ b/net/rds/connection.c @@ -126,7 +126,10 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr, struct rds_transport *loop_trans; unsigned long flags; int ret; + struct rds_transport *otrans = trans; + if (!is_outgoing && otrans->t_type == RDS_TRANS_TCP) + goto new_conn; rcu_read_lock(); conn = rds_conn_lookup(head, laddr, faddr, trans); if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport && @@ -142,6 +145,7 @@ static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr, if (conn) goto out; +new_conn: conn = kmem_cache_zalloc(rds_conn_slab, gfp); if (!conn) { conn = ERR_PTR(-ENOMEM); -- cgit v1.2.1 From c82ac7e69efe6dbe370d6ba84e2666d7692ef1c2 Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Tue, 5 May 2015 15:20:52 -0400 Subject: net/rds: RDS-TCP: only initiate reconnect attempt on outgoing TCP socket. When the peer of an RDS-TCP connection restarts, a reconnect attempt should only be made from the active side of the TCP connection, i.e. the side that has a transient TCP port number. Do not add the passive side of the TCP connection to the c_hash_node and thus avoid triggering rds_queue_reconnect() for passive rds connections. Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller --- net/rds/connection.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'net/rds/connection.c') diff --git a/net/rds/connection.c b/net/rds/connection.c index 60f0cd6ed15f..da6da57e5f36 100644 --- a/net/rds/connection.c +++ b/net/rds/connection.c @@ -234,13 +234,22 @@ new_conn: /* Creating normal conn */ struct rds_connection *found; - found = rds_conn_lookup(head, laddr, faddr, trans); + if (!is_outgoing && otrans->t_type == RDS_TRANS_TCP) + found = NULL; + else + found = rds_conn_lookup(head, laddr, faddr, trans); if (found) { trans->conn_free(conn->c_transport_data); kmem_cache_free(rds_conn_slab, conn); conn = found; } else { - hlist_add_head_rcu(&conn->c_hash_node, head); + if ((is_outgoing && otrans->t_type == RDS_TRANS_TCP) || + (otrans->t_type != RDS_TRANS_TCP)) { + /* Only the active side should be added to + * reconnect list for TCP. + */ + hlist_add_head_rcu(&conn->c_hash_node, head); + } rds_cong_add_conn(conn); rds_conn_count++; } -- cgit v1.2.1