netfilter: nf_conntrack_tcp: decrease timeouts while data in unacknowledged

In order to time out dead connections quicker, keep track of outstanding data
and cap the timeout.

Suggested by Herbert Xu.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/netfilter/nf_conntrack_tcp.h b/include/linux/netfilter/nf_conntrack_tcp.h
index 22ce29995f13..a049df4f2236 100644
--- a/include/linux/netfilter/nf_conntrack_tcp.h
+++ b/include/linux/netfilter/nf_conntrack_tcp.h
@@ -30,6 +30,9 @@ enum tcp_conntrack {
 /* Be liberal in window checking */
 #define IP_CT_TCP_FLAG_BE_LIBERAL               0x08
 
+/* Has unacknowledged data */
+#define IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED      0x10
+
 struct nf_ct_tcp_flags {
         u_int8_t flags;
         u_int8_t mask;