Index: usr.sbin/wlandebug/Makefile
===================================================================
--- usr.sbin/wlandebug/Makefile
+++ usr.sbin/wlandebug/Makefile
@@ -3,6 +3,8 @@
 PROG=	wlandebug
 MAN=	wlandebug.8
 
+LIBADD+=	80211
+
 WARNS?=	2
 
 .include <bsd.prog.mk>
Index: usr.sbin/wlandebug/wlandebug.c
===================================================================
--- usr.sbin/wlandebug/wlandebug.c
+++ usr.sbin/wlandebug/wlandebug.c
@@ -34,15 +34,23 @@
  * (default interface is wlan.0).
  */
 #include <sys/types.h>
+#include <sys/socket.h>
 #include <sys/sysctl.h>
 
+#include <net/if.h>
+
+#include <net80211/ieee80211_ioctl.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
 #include <getopt.h>
 #include <string.h>
 #include <err.h>
+#include <unistd.h>
 
+#include <lib80211/lib80211_ioctl.h>
+
 #define	N(a)	(sizeof(a)/sizeof(a[0]))
 
 const char *progname;
@@ -147,7 +155,7 @@
 		snprintf(oid, oidlen, "net.%s.debug", wlan);
 #elif __FreeBSD__
 	if (wlan)
-		snprintf(oid, oidlen, "net.wlan.%s.debug", wlan+4);
+		snprintf(oid, oidlen, "net.wlan.%s.debug", wlan);
 	else
 		snprintf(oid, oidlen, "net.wlan.debug");
 #elif __NetBSD__
@@ -160,6 +168,26 @@
 #endif
 }
 
+static void
+change_iface_unit(char *oid, size_t oid_size, char *name)
+{
+	int s, val;
+	char *unit_str;
+
+	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ||
+	    lib80211_get80211val(s, name, IEEE80211_IOC_UNIT, &val) ||
+	    asprintf(&unit_str, "%d", val) < 0) {
+		/* fall back to the old method */
+		if (strncmp(name, "wlan", 4) != 0)
+			errx(1, "expecting a wlan interface name");
+		setoid(oid, oid_size, &name[4]);
+	} else {
+		setoid(oid, oid_size, unit_str);
+		free(unit_str);
+	}
+	close(s);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -171,7 +199,7 @@
 	char oid[256];
 
 	progname = argv[0];
-	setoid(oid, sizeof(oid), "wlan0");
+	setoid(oid, sizeof(oid), "0");
 	if (argc > 1) {
 		if (strcmp(argv[1], "-d") == 0) {
 			setoid(oid, sizeof(oid), NULL);
@@ -179,9 +207,7 @@
 		} else if (strcmp(argv[1], "-i") == 0) {
 			if (argc <= 2)
 				errx(1, "missing interface name for -i option");
-			if (strncmp(argv[2], "wlan", 4) != 0)
-				errx(1, "expecting a wlan interface name");
-			setoid(oid, sizeof(oid), argv[2]);
+			change_iface_unit(oid, sizeof(oid), argv[2]);
 			argc -= 2, argv += 2;
 		} else if (strcmp(argv[1], "-?") == 0)
 			usage();