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authorSowmini Varadhan <sowmini.varadhan@oracle.com>2016-05-18 17:06:24 (GMT)
committerDavid S. Miller <davem@davemloft.net>2016-05-20 23:19:57 (GMT)
commitc948bb5c2cc4d63f9d76fc02baf5a8331e3cd27f (patch)
tree6f7e5d447ec8020d67980cd51e5ff6b798b4086f
parent37e14f4fe2991f6089a9c8a3830e3ab634ec7190 (diff)
downloadlinux-c948bb5c2cc4d63f9d76fc02baf5a8331e3cd27f.tar.xz
RDS: TCP: Avoid rds connection churn from rogue SYNs
When a rogue SYN is received after the connection arbitration algorithm has converged, the incoming SYN should not needlessly quiesce the transmit path, and it should not result in needless TCP connection resets due to re-execution of the connection arbitration logic. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/rds/tcp_listen.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 094a8ca..4bf4bef 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -132,11 +132,13 @@ int rds_tcp_accept_one(struct socket *sock)
* so we must quiesce any send threads before resetting
* c_transport_data.
*/
- wait_event(conn->c_waitq,
- !test_bit(RDS_IN_XMIT, &conn->c_flags));
- if (ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr)) {
+ if (ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr) ||
+ !conn->c_outgoing) {
goto rst_nsk;
- } else if (rs_tcp->t_sock) {
+ } else {
+ atomic_set(&conn->c_state, RDS_CONN_CONNECTING);
+ wait_event(conn->c_waitq,
+ !test_bit(RDS_IN_XMIT, &conn->c_flags));
rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
conn->c_outgoing = 0;
}