[NETFILTER]: Add new iptables "connbytes" match

This patch ads a new "connbytes" match that utilizes the CONFIG_NF_CT_ACCT
per-connection byte and packet counters.  Using it you can do things like
packet classification on average packet size within a connection.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter_ipv4/ipt_connbytes.h

@@ -0,0 +1,25 @@
+#ifndef _IPT_CONNBYTES_H
+#define _IPT_CONNBYTES_H
+
+enum ipt_connbytes_what {
+	IPT_CONNBYTES_WHAT_PKTS,
+	IPT_CONNBYTES_WHAT_BYTES,
+	IPT_CONNBYTES_WHAT_AVGPKT,
+};
+
+enum ipt_connbytes_direction {
+	IPT_CONNBYTES_DIR_ORIGINAL,
+	IPT_CONNBYTES_DIR_REPLY,
+	IPT_CONNBYTES_DIR_BOTH,
+};
+
+struct ipt_connbytes_info
+{
+	struct {
+		aligned_u64 from;	/* count to be matched */
+		aligned_u64 to;		/* count to be matched */
+	} count;
+	u_int8_t what;		/* ipt_connbytes_what */
+	u_int8_t direction;	/* ipt_connbytes_direction */
+};
+#endif