ifconfig & Network preferences: Actually trigger scans using BNetworkDevice.

Fixes #12034, and a variety of other strange "no wireless networks
appear" bugs that have plagued Haiku for years.

Change-Id: I734cb8084e8a626b8e03511519609bf80c1559eb
Reviewed-on: https://review.haiku-os.org/552
Reviewed-by: waddlesplash <[email protected]>

src/bin/network/ifconfig/ifconfig.cpp

@@ -281,6 +281,7 @@ configure_wireless(const char* name, char* const* args, int32 argCount)
 {
 	enum {
 		NONE,
+		SCAN,
 		LIST,
 		JOIN,
 		LEAVE,
@@ -290,7 +291,9 @@ configure_wireless(const char* name, char* const* args, int32 argCount)
 	int controlOption = -1;
 	int controlValue = -1;
 
-	if (!strcmp(args[0], "list") || !strcmp(args[0], "scan"))
+	if (!strcmp(args[0], "scan"))
+		mode = SCAN;
+	else if (!strcmp(args[0], "list"))
 		mode = LIST;
 	else if (!strcmp(args[0], "join"))
 		mode = JOIN;
@@ -324,6 +327,16 @@ configure_wireless(const char* name, char* const* args, int32 argCount)
 	argCount--;
 
 	switch (mode) {
+		case SCAN:
+		{
+			status_t status = device.Scan(true, true);
+			if (status != B_OK) {
+				fprintf(stderr, "%s: Scan on \"%s\" failed: %s\n", kProgramName,
+					name, strerror(status));
+				exit(1);
+			}
+			// fall through
+		}
 		case LIST:
 		{
 			// list wireless network(s)

src/preferences/network/InterfaceView.cpp

@@ -262,6 +262,23 @@ InterfaceView::_Update(bool updateWirelessNetworks)
 
 		wireless_network network;
 		int32 count = 0;
+		cookie = 0;
+		if ((fPulseCount % 15) == 0
+				&& device.GetNextNetwork(cookie, network) != B_OK) {
+			// We don't seem to know of any networks, and it's been long
+			// enough since the last scan, so trigger one to try and
+			// find some networks.
+			device.Scan(false, false);
+
+			// We don't want to block for the full length of the scan, but
+			// 50ms is often more than enough to find at least one network,
+			// and the increase in perceived QoS to the user of not seeing
+			// "no wireless networks" if we can avoid it is great enough
+			// to merit such a wait. It's only just over ~4 vertical
+			// retraces, anyway.
+			snooze(50 * 1000);
+		}
+
 		cookie = 0;
 		while (device.GetNextNetwork(cookie, network) == B_OK) {
 			BMessage* message = new BMessage(kMsgJoinNetwork);