net80211/ifconfig: print hardware device name for wlan interfaces

Add IEEE80211_IOC_IC_NAME to query the ic_name field and in ifconfig
to print the parent interface again. This functionality was lost
around r287197. It helps in case of multiple wlan interfaces and
multiple underlying hardware devices to keep track which wlan
interface belongs to which physical device.

Sponsored by:	Rubicon Communications, LLC (d/b/a "Netgate")
Reviewed by:	adrian, Idwer Vollering
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D25832

sbin/ifconfig/ifieee80211.c

@@ -4779,6 +4779,23 @@ getid(int s, int ix, void *data, size_t len, int *plen, int mesh)
 	return 0;
 }
 
+static int
+getdevicename(int s, void *data, size_t len, int *plen)
+{
+	struct ieee80211req ireq;
+
+	(void) memset(&ireq, 0, sizeof(ireq));
+	(void) strlcpy(ireq.i_name, name, sizeof(ireq.i_name));
+	ireq.i_type = IEEE80211_IOC_IC_NAME;
+	ireq.i_val = -1;
+	ireq.i_data = data;
+	ireq.i_len = len;
+	if (ioctl(s, SIOCG80211, &ireq) < 0)
+		return (-1);
+	*plen = ireq.i_len;
+	return (0);
+}
+
 static void
 ieee80211_status(int s)
 {
@@ -5503,6 +5520,12 @@ ieee80211_status(int s)
 	}
 
 	LINE_BREAK();
+
+	if (getdevicename(s, data, sizeof(data), &len) < 0)
+		return;
+	LINE_CHECK("parent interface: %s", data);
+
+	LINE_BREAK();
 }
 
 static int

share/man/man4/net80211.4

@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 10, 2009
+.Dd August 7, 2020
 .Dt NET80211 4
 .Os
 .Sh NAME
@@ -393,6 +393,16 @@ Valid values are:
 and
 .Dv IEEE80211_HWMP_ROOTMODE_RANN
 (send broadcast Root Announcement (RANN) frames).
+.It Dv IEEE80211_IOC_IC_NAME
+Return the underlying hardware
+.Xr device 9
+name in the buffer pointed to by
+.Va i_data
+and the name length including terminating NUL character in
+.Va i_len .
+If the buffer length is too small to hold the full name
+.Er EINVAL
+will be returned.
 .It Dv IEEE80211_IOC_INACTIVITY
 Return whether or not the system handles inactivity processing in
 .Va i_val .

sys/net80211/ieee80211_ioctl.c

@@ -785,6 +785,13 @@ ieee80211_ioctl_get80211(struct ieee80211vap *vap, u_long cmd,
 	int error = 0;
 
 	switch (ireq->i_type) {
+	case IEEE80211_IOC_IC_NAME:
+		len = strlen(ic->ic_name) + 1;
+		if (len > ireq->i_len)
+			return (EINVAL);
+		ireq->i_len = len;
+		error = copyout(ic->ic_name, ireq->i_data, ireq->i_len);
+		break;
 	case IEEE80211_IOC_SSID:
 		switch (vap->iv_state) {
 		case IEEE80211_S_INIT:

sys/net80211/ieee80211_ioctl.h

@@ -743,6 +743,9 @@ struct ieee80211req {
 #define	IEEE80211_IOC_QUIET_OFFSET	207	/* Quiet Offset */
 #define	IEEE80211_IOC_QUIET_DUR		208	/* Quiet Duration */
 #define	IEEE80211_IOC_QUIET_COUNT	209	/* Quiet Count */
+
+#define	IEEE80211_IOC_IC_NAME		210	/* HW device name. */
+
 /*
  * Parameters for controlling a scan requested with
  * IEEE80211_IOC_SCAN_REQ.