[NETFILTER]: Add SANE connection tracking helper

This is nf_conntrack_sane, a netfilter connection tracking helper module
for the SANE protocol used by the 'saned' daemon to make scanners available
via network. The SANE protocol uses separate control & data connections,
similar to passive FTP. The helper module is needed to recognize the data
connection as RELATED to the control one.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/nf_conntrack_sane.h

@@ -0,0 +1,21 @@
+#ifndef _NF_CONNTRACK_SANE_H
+#define _NF_CONNTRACK_SANE_H
+/* SANE tracking. */
+
+#ifdef __KERNEL__
+
+#define SANE_PORT	6566
+
+enum sane_state {
+	SANE_STATE_NORMAL,
+	SANE_STATE_START_REQUESTED,
+};
+
+/* This structure exists only once per master */
+struct nf_ct_sane_master {
+	enum sane_state state;
+};
+
+#endif /* __KERNEL__ */
+
+#endif /* _NF_CONNTRACK_SANE_H */