[DCCP] CCID2: Code optimizations

These are code optimizations which are relevant when dealing with large
windows.  They are not coded the way I would like to, but they do the job for
the short-term.  This patch should be more neat.

Commiter note: Changed the seqno comparisions to use {after,before}48 to handle
               wrapping.

Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 5b2ef4a..a97a899 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -72,6 +72,7 @@
 	int			ccid2hctx_rpdupack;
 	int			ccid2hctx_sendwait;
 	unsigned long		ccid2hctx_last_cong;
+	u64			ccid2hctx_high_ack;
 };
 
 struct ccid2_hc_rx_sock {