dccp: send Confirm options only once

If a connection is in the OPEN state, remove feature negotiation Confirm
options from the list of options after sending them once; as such options
are NOT supposed to be retransmitted and are ONLY supposed to be sent in
response to a Change option (RFC 4340 6.2).

Signed-off-by: Samuel Jero <sj323707@ohio.edu>
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

1 files changed, 16 insertions, 5 deletions

diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index ad6f9e2cac1a..23cea0ee3101 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -665,11 +665,22 @@ int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq,
                         return -1;
                 if (pos->needs_mandatory && dccp_insert_option_mandatory(skb))
                         return -1;
-                /*
-                 * Enter CHANGING after transmitting the Change option (6.6.2).
-                 */
-                if (pos->state == FEAT_INITIALISING)
-                        pos->state = FEAT_CHANGING;
+
+                if (skb->sk->sk_state == DCCP_OPEN &&
+                    (opt == DCCPO_CONFIRM_R || opt == DCCPO_CONFIRM_L)) {
+                        /*
+                         * Confirms don't get retransmitted (6.6.3) once the
+                         * connection is in state OPEN
+                         */
+                        dccp_feat_list_pop(pos);
+                } else {
+                        /*
+                         * Enter CHANGING after transmitting the Change
+                         * option (6.6.2).
+                         */
+                        if (pos->state == FEAT_INITIALISING)
+                                pos->state = FEAT_CHANGING;
+                }
         }
         return 0;
 }