diff --git a/sys/net/if.c b/sys/net/if.c
index 272814101f9..7ffb296682f 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1145,6 +1145,10 @@ ifhwioctl(u_long cmd, struct ifnet *ifp, caddr_t data, struct thread *td)
 
 	ifr = (struct ifreq *)data;
 	switch (cmd) {
+	case SIOCGIFINDEX:
+		ifr->ifr_index = ifp->if_index;
+		break;
+
 	case SIOCGIFFLAGS:
 		ifr->ifr_flags = ifp->if_flags;
 		break;
diff --git a/sys/net/if.h b/sys/net/if.h
index eb4d19907c3..83116b96825 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -200,6 +200,7 @@ struct	ifreq {
 		struct	sockaddr ifru_dstaddr;
 		struct	sockaddr ifru_broadaddr;
 		short	ifru_flags[2];
+		short	ifru_index;
 		int	ifru_metric;
 		int	ifru_mtu;
 		int	ifru_phys;
@@ -219,6 +220,7 @@ struct	ifreq {
 #define	ifr_data	ifr_ifru.ifru_data	/* for use by interface */
 #define	ifr_reqcap	ifr_ifru.ifru_cap[0]	/* requested capabilities */
 #define	ifr_curcap	ifr_ifru.ifru_cap[1]	/* current capabilities */
+#define	ifr_index	ifr_ifru.ifru_index	/* interface index */
 };
 
 #define	_SIZEOF_ADDR_IFREQ(ifr) \
diff --git a/sys/sys/sockio.h b/sys/sys/sockio.h
index c681f8e57ef..03ea70ced5b 100644
--- a/sys/sys/sockio.h
+++ b/sys/sys/sockio.h
@@ -79,6 +79,7 @@
 #define	SIOCDLIFADDR	 _IOW('i', 29, struct if_laddrreq) /* delete IF addr */
 #define	SIOCSIFCAP	 _IOW('i', 30, struct ifreq)	/* set IF features */
 #define	SIOCGIFCAP	_IOWR('i', 31, struct ifreq)	/* get IF features */
+#define	SIOCGIFINDEX	_IOWR('i', 32, struct ifreq)	/* get IF index */
 
 #define	SIOCADDMULTI	 _IOW('i', 49, struct ifreq)	/* add m'cast addr */
 #define	SIOCDELMULTI	 _IOW('i', 50, struct ifreq)	/* del m'cast addr */