dccp ccid-2: Algorithm to update buffer state

This provides a routine to consistently update the buffer state when the
peer acknowledges receipt of Ack Vectors; updating state in the list of Ack
Vectors as well as in the circular buffer.

While based on RFC 4340, several additional (and necessary) precautions were
added to protect the consistency of the buffer state. These additions are
essential, since analysis and experience showed that the basic algorithm was
insufficient for this task (which lead to problems that were hard to debug).

The algorithm now
 * deals with HC-sender acknowledging to HC-receiver and vice versa,
 * keeps track of the last unacknowledged but received seqno in tail_ackno,
 * has special cases to reset the overflow condition when appropriate,
 * is protected against receiving older information (would mess up buffer state).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/dccp/input.c b/net/dccp/input.c
index c7aeeba859d4..f91cf5ada306 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -165,8 +165,8 @@ static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
         struct dccp_sock *dp = dccp_sk(sk);
 
         if (dp->dccps_hc_rx_ackvec != NULL)
-                dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
-                                            DCCP_SKB_CB(skb)->dccpd_ack_seq);
+                dccp_ackvec_clear_state(dp->dccps_hc_rx_ackvec,
+                                        DCCP_SKB_CB(skb)->dccpd_ack_seq);
 }
 
 static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)