Introduction

I’ve long wanted to build a WiFi-based application—ideally one that also records GPS location data for wardriving. I searched for manageable C# solutions integrated with .NET.

First Attempts

I explored many WMI tutorials, but on Windows 7, I lacked the needed namespaces like MSNdis_80211_ServiceSetIdentifier.

Eventually, I discovered the WLan API (available since Windows XP SP3), usable via P/Invoke. Fortunately, someone made a ManagedWifi wrapper for it—perfect!

The Scanner

I wrote a small utility that scans for SSIDs across all interfaces and retrieves their MAC addresses.

The code was based on help from a Stack Overflow thread and enhanced with info on BSSID access.

Code Snippet

static void Main(string[] args)
{
    WlanClient client = new WlanClient();
    foreach (WlanClient.WlanInterface wlanIface in client.Interfaces)
    {
        Wlan.WlanBssEntry[] wlanBssEntries = wlanIface.GetNetworkBssList();
        foreach (Wlan.WlanBssEntry network in wlanBssEntries)
        {
            byte[] macAddr = network.dot11Bssid;
            string tMac = string.Join(":", macAddr.Select(b => b.ToString("x2")).ToArray()).ToUpper();

            Console.WriteLine("Found network with SSID {0}.", GetStringForSSID(network.dot11Ssid));
            Console.WriteLine("Signal: {0}%.", network.linkQuality);
            Console.WriteLine("BSS Type: {0}.", network.dot11BssType);
            Console.WriteLine("MAC: {0}.", tMac);
            Console.WriteLine();
        }
    }

    Console.ReadLine();
}

static string GetStringForSSID(Wlan.Dot11Ssid ssid)
{
    return Encoding.ASCII.GetString(ssid.SSID, 0, (int)ssid.SSIDLength);
}

Conclusion

With just a few lines and the ManagedWifi wrapper, I now have a solid base for my wardriving app—including signal strength, MAC address, and SSID collection. GPS integration and location storage will be next.

More to come!