[IPV6]: ROUTE: Add accept_ra_rtr_pref sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 2c3b799..108b75d 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -147,6 +147,9 @@
 	__s32		max_addresses;
 	__s32		accept_ra_defrtr;
 	__s32		accept_ra_pinfo;
+#ifdef CONFIG_IPV6_ROUTER_PREF
+	__s32		accept_ra_rtr_pref;
+#endif
 	void		*sysctl;
 };
 
@@ -171,6 +174,7 @@
 	DEVCONF_FORCE_MLD_VERSION,
 	DEVCONF_ACCEPT_RA_DEFRTR,
 	DEVCONF_ACCEPT_RA_PINFO,
+	DEVCONF_ACCEPT_RA_RTR_PREF,
 	DEVCONF_MAX
 };