confd: drop wifi-scanner in favor of wpa_supplicant autoscan

The trick to starting the scanner mode is to have a dummy network that
cannot associate with anything.

Fixes #1193

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/rootfs/etc/finit.d/available/wifi@.conf

@@ -1,5 +1,3 @@
 service name:wpa_supplicant :%i \
-			[2345] wpa_supplicant -s -i %i -c /etc/wpa_supplicant-%i.conf -P/var/run/wpa_supplicant-%i.pid \
-			       -- Wi-Fi Station @%i
-
-task name:wifi-scanner :%i [2345] <pid/wpa_supplicant:%i> /usr/libexec/infix/wifi-scanner %i -- Start scanning for SSID @%i
+	[2345] wpa_supplicant -s -i %i -c /etc/wpa_supplicant-%i.conf -P/var/run/wpa_supplicant-%i.pid \
+	-- Wi-Fi Station @%i

board/common/rootfs/usr/libexec/infix/wifi-scanner

@@ -1,16 +0,0 @@
-#!/bin/sh
-
-if [ $# -ne 1 ]; then
-	echo "usage: $0 <ifname>"
-	exit 1
-fi
-ifname=$1
-
-TIMEOUT=300
-status=$(wpa_cli -i $ifname scan)
-while [ "$status" != "OK" ]; do
-	status=$(wpa_cli -i $ifname scan)
-	TIMEOUT=$((TIMEOUT-1))
-	[ $TIMEOUT -eq 0 ] && logger -t wifi-scanner "Failed to start scanning $ifname" && exit 1
-	sleep 0.5
-done

src/confd/src/if-wifi.c

@@ -103,6 +103,10 @@ static int wifi_gen_station(struct lyd_node *cif)
 		goto out;
 	}
 
+	/*
+	 * Background scanning every 10 seconds while not associated, when we
+	 * have an SSID (below), bgscan assumes this task.
+	 */
 	fprintf(wpa_supplicant,
 		"ctrl_interface=/run/wpa_supplicant\n"
 		"autoscan=periodic:10\n"
@@ -121,14 +125,27 @@ static int wifi_gen_station(struct lyd_node *cif)
 		}
 		fprintf(wpa_supplicant,
 			"network={\n"
-			"bgscan=\"simple: 30:-45:300\"\n"
-			"ssid=\"%s\"\n"
-			"%s\n"
+			"  bgscan=\"simple: 30:-45:300\"\n"
+			"  ssid=\"%s\"\n"
+			"  %s\n"
 			"}\n", ssid, security_str);
 		free(security_str);
 	} else {
 		/* Scan-only mode - no station container configured */
-		fprintf(wpa_supplicant, "# Scan-only mode - no network configured\n");
+		fprintf(wpa_supplicant, "# Scan-only - need dummy network for state machine\n");
+		/*
+		 * This prevents the daemon from actually trying to associate and fail,
+		 * 'bssid' with a reserved/impossible MAC address prevents it from ever
+		 * actually \"finding\" and joining a random open AP
+		 */
+		fprintf(wpa_supplicant,
+			"network={\n"
+			"  ssid=\"\"\n"
+			"  key_mgmt=NONE\n"
+			"  disabled=0\n"
+			"  bssid=00:00:00:00:00:01\n"
+			"  scan_ssid=1\n"
+			"}\n");
 	}
 
 out: