[IPV4]: Primary and secondary addresses

Add an option to make secondary IP addresses get promoted
when primary IP addresses are removed from the device.
It defaults to off to preserve existing behavior.

Signed-off-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 6fafb27..7e1e15f 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -29,6 +29,7 @@
 	int	no_xfrm;
 	int	no_policy;
 	int	force_igmp_version;
+	int	promote_secondaries;
 	void	*sysctl;
 };
 
@@ -71,6 +72,7 @@
 #define IN_DEV_SEC_REDIRECTS(in_dev)	(ipv4_devconf.secure_redirects || (in_dev)->cnf.secure_redirects)
 #define IN_DEV_IDTAG(in_dev)		((in_dev)->cnf.tag)
 #define IN_DEV_MEDIUM_ID(in_dev)	((in_dev)->cnf.medium_id)
+#define IN_DEV_PROMOTE_SECONDARIES(in_dev)	(ipv4_devconf.promote_secondaries || (in_dev)->cnf.promote_secondaries)
 
 #define IN_DEV_RX_REDIRECTS(in_dev) \
 	((IN_DEV_FORWARD(in_dev) && \