[DCCP]: Add support for abortive release

This continues from the previous patch and adds support for actively aborting
a DCCP connection, using a Reset Code 2, "Aborted" to inform the peer of an
abortive release.

I have tried this in various client/server settings and it works as expected.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 2 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 5f47b458ed8f..73006b747678 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -276,6 +276,12 @@ static inline int dccp_listen_start(struct sock *sk, int backlog)
         return inet_csk_listen_start(sk, backlog);
 }
 
+static inline int dccp_need_reset(int state)
+{
+        return state != DCCP_CLOSED && state != DCCP_LISTEN &&
+               state != DCCP_REQUESTING;
+}
+
 int dccp_disconnect(struct sock *sk, int flags)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
@@ -286,10 +292,15 @@ int dccp_disconnect(struct sock *sk, int flags)
         if (old_state != DCCP_CLOSED)
                 dccp_set_state(sk, DCCP_CLOSED);
 
-        /* ABORT function of RFC793 */
+        /*
+         * This corresponds to the ABORT function of RFC793, sec. 3.8
+         * TCP uses a RST segment, DCCP a Reset packet with Code 2, "Aborted".
+         */
         if (old_state == DCCP_LISTEN) {
                 inet_csk_listen_stop(sk);
-        /* FIXME: do the active reset thing */
+        } else if (dccp_need_reset(old_state)) {
+                dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
+                sk->sk_err = ECONNRESET;
         } else if (old_state == DCCP_REQUESTING)
                 sk->sk_err = ECONNRESET;