--- src/sys/net/if.h	2006/12/19 00:11:12	1.17
+++ src/sys/net/if.h	2007/03/24 05:57:49	1.18
@@ -56,6 +56,13 @@
 
 #endif
 
+/*
+ * Values for if_link_state.
+ */
+#define	LINK_STATE_UNKNOWN	0	/* link invalid/unknown */
+#define	LINK_STATE_DOWN		1	/* link is down */
+#define	LINK_STATE_UP		2	/* link is up */
+
 struct ifnet;
 
 /*
@@ -111,6 +118,7 @@ struct if_data {
 	u_char	ifi_xmitquota;		/* polling quota for xmit intrs */
 	u_long	ifi_mtu;		/* maximum transmission unit */
 	u_long	ifi_metric;		/* routing metric (external only) */
+	u_long  ifi_link_state;		/* current link state */
 	u_long	ifi_baudrate;		/* linespeed */
 	/* volatile statistics */
 	u_long	ifi_ipackets;		/* packets received on interface */