dccp ccid-2: Implementation of circular Ack Vector buffer with overflow handling
This completes the implementation of a circular buffer for Ack Vectors, by
extending the current (linear array-based) implementation. The changes are:
(a) An `overflow' flag to deal with the case of overflow. As before, dynamic
growth of the buffer will not be supported; but code will be added to deal
robustly with overflowing Ack Vector buffers.
(b) A `tail_seqno' field. When naively implementing the algorithm of Appendix A
in RFC 4340, problems arise whenever subsequent Ack Vector records overlap,
which can bring the entire run length calculation completely out of synch.
(This is documented on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/\
ack_vectors/tracking_tail_ackno/ .)
(c) The buffer length is now computed dynamically (i.e. current fill level),
as the span between head to tail.
As a result, dccp_ackvec_pending() is now simpler - the #ifdef is no longer
necessary since buf_empty is always true when IP_DCCP_ACKVEC is not configured.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index a8ed459..19fafd5 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -457,12 +457,15 @@
dp->dccps_awh = dp->dccps_gss;
}
+static inline int dccp_ackvec_pending(const struct sock *sk)
+{
+ return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL &&
+ !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec);
+}
+
static inline int dccp_ack_pending(const struct sock *sk)
{
- const struct dccp_sock *dp = dccp_sk(sk);
- return (dp->dccps_hc_rx_ackvec != NULL &&
- dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
- inet_csk_ack_scheduled(sk);
+ return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk);
}
extern int dccp_feat_finalise_settings(struct dccp_sock *dp);