rtnl: add a new type of msg to advertise protocol configuration

A new type is added to allow userland to monitor protocol configuration, like
IPv4 or IPv6.
For example, monitoring the state of the forwarding status of an interface of
the system.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/netconf.h

+#ifndef _UAPI_LINUX_NETCONF_H_
+#define _UAPI_LINUX_NETCONF_H_
+
+#include <linux/types.h>
+#include <linux/netlink.h>
+
+struct netconfmsg {
+	__u8	ncm_family;
+};
+
+enum {
+	NETCONFA_UNSPEC,
+	NETCONFA_IFINDEX,
+	NETCONFA_FORWARDING,
+	__NETCONFA_MAX
+};
+#define NETCONFA_MAX	(__NETCONFA_MAX - 1)
+
+#define NETCONFA_IFINDEX_ALL		-1
+#define NETCONFA_IFINDEX_DEFAULT	-2
+
+#endif /* _UAPI_LINUX_NETCONF_H_ */

include/uapi/linux/rtnetlink.h

@@ -120,6 +120,11 @@ enum {
 	RTM_SETDCB,
 #define RTM_SETDCB RTM_SETDCB
 
+	RTM_NEWNETCONF = 80,
+#define RTM_NEWNETCONF RTM_NEWNETCONF
+	RTM_GETNETCONF = 82,
+#define RTM_GETNETCONF RTM_GETNETCONF
+
 	__RTM_MAX,
 #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
 };