Add a new variable, ifi_epoch, to struct if_data. It is set to the last

time the interface counters were zeroed, currently the time if_attach()
was called.  It is indentended to be a valid value for RFC2233's
ifCounterDiscontinuityTime and to make it easier for applications to
verify that the interface they find at a given index is the one that was
there last time they looked.

An if_epoch "compatability" macro has not been created as ifi_epoch has
never been a member of struct ifnet.

Approved by:	andre, bms, wollman

UPDATING

@@ -23,6 +23,11 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 6.x IS SLOW:
 	developers choose to disable these features on build machines
 	to maximize performance.
 
+20040830:
+	A new variable, ifi_epoch, has been added to struct if_data
+	which is part if struct ifnet.  This means all network drivers
+	and network monitoring applications need to be recompiled.
+
 20040828:
 	The default configuration for the network stack has been changed
 	such that it now runs without the Giant lock unless configured

sys/net/if.c

@@ -387,6 +387,7 @@ if_attach(struct ifnet *ifp)
 	TAILQ_INIT(&ifp->if_multiaddrs);
 	knlist_init(&ifp->if_klist, NULL);
 	getmicrotime(&ifp->if_lastchange);
+	getmicrotime(&ifp->if_data.ifi_epoch);
 
 #ifdef MAC
 	mac_init_ifnet(ifp);

sys/net/if.h

@@ -103,6 +103,7 @@ struct if_data {
 	u_long	ifi_hwassist;		/* HW offload capabilities */
 	u_long	ifi_unused;		/* XXX was ifi_xmittiming */
 	struct	timeval ifi_lastchange;	/* time of last administrative change */
+	struct	timeval ifi_epoch;	/* time of creation or stat reset */
 };
 
 #define	IFF_UP		0x1		/* interface is up */

sys/sys/param.h

@@ -57,7 +57,7 @@
  *		is created, otherwise 1.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 600001	/* Master, propagated to newvers */
+#define __FreeBSD_version 600002	/* Master, propagated to newvers */
 
 #ifndef LOCORE
 #include <sys/types.h>