tcp: metrics: New netlink attribute for src IP and dumped in netlink reply

This patch adds a new netlink attribute for the source-IP and appends it
to the netlink reply. Now, iproute2 can have access to the source-IP.

Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/tcp_metrics.h b/include/uapi/linux/tcp_metrics.h
index cb5157b..54a37b1 100644
--- a/include/uapi/linux/tcp_metrics.h
+++ b/include/uapi/linux/tcp_metrics.h
@@ -35,6 +35,8 @@
 	TCP_METRICS_ATTR_FOPEN_SYN_DROPS,	/* u16, count of drops */
 	TCP_METRICS_ATTR_FOPEN_SYN_DROP_TS,	/* msecs age */
 	TCP_METRICS_ATTR_FOPEN_COOKIE,		/* binary */
+	TCP_METRICS_ATTR_SADDR_IPV4,		/* u32 */
+	TCP_METRICS_ATTR_SADDR_IPV6,		/* binary */
 
 	__TCP_METRICS_ATTR_MAX,
 };