Added channel width detection to the BssNetworkInfo class.

Source/ManagedNativeWifi/BssNetworkInfo.cs

@@ -54,11 +54,16 @@ public class BssNetworkInfo
 	/// <summary>
 	/// Channel
 	/// </summary>
-	public int Channel { get; }
-
-	/// <summary>
-	/// Constructor
-	/// </summary>
+	public int Channel { get; }
+
+	/// <summary>
+	///  Width of the channel (KHz)
+	/// </summary>
+	public int Width { get; internal set; }
+
+		/// <summary>
+		/// Constructor
+		/// </summary>
 	public BssNetworkInfo(
 		NetworkIdentifier ssid,
 		BssType bssType,
@@ -68,7 +73,8 @@ public BssNetworkInfo(
 		int linkQuality,
 		int frequency,
 		float band,
-		int channel)
+		int channel,
+		int width)
 	{
 		this.Ssid = ssid;
 		this.BssType = bssType;
@@ -78,7 +84,8 @@ public BssNetworkInfo(
 		this.LinkQuality = linkQuality;
 		this.Frequency = frequency;
 		this.Band = band;
-		this.Channel = channel;
+		this.Channel = channel;
+		this.Width = width;
 	}
 }
 
@@ -111,7 +118,8 @@ public BssNetworkPack(
 		int linkQuality,
 		int frequency,
 		float band,
-		int channel) : base(
+		int channel,
+		int width) : base(
 			ssid: ssid,
 			bssType: bssType,
 			bssid: bssid,
@@ -120,7 +128,8 @@ public BssNetworkPack(
 			linkQuality: linkQuality,
 			frequency: frequency,
 			band: band,
-			channel: channel)
+			channel: channel,
+			width)
 	{
 		this.InterfaceInfo = interfaceInfo;
 	}
@@ -137,6 +146,7 @@ internal BssNetworkPack(
 			linkQuality: bssNetworkInfo.LinkQuality,
 			frequency: bssNetworkInfo.Frequency,
 			band: bssNetworkInfo.Band,
-			channel: bssNetworkInfo.Channel)
+			channel: bssNetworkInfo.Channel,
+			width: bssNetworkInfo.Width)
 	{ }
 }

Source/ManagedNativeWifi/NativeWifi.cs

@@ -477,13 +477,61 @@ private static bool TryConvertBssNetwork(WLAN_BSS_ENTRY bssEntry, out BssNetwork
 				linkQuality: (int)bssEntry.uLinkQuality,
 				frequency: (int)bssEntry.ulChCenterFrequency,
 				band: band,
-				channel: channel);
+				channel: channel,
+				width: GetChannelWidth(bssEntry));
 			return true;
 		}
 		bssNetworkInfo = null;
 		return false;
 	}
 
+	/// <summary>
+	/// Extracts the channel width from the Information Element data of the bssEntry.
+	/// </summary>
+	/// <remarks>
+	///	This code is based on the Python code here:
+	///	https://github.com/opetryna/win32wifi/blob/4f6bedab47c8506738e7a14b07714d032a74f8a7/win32wifi/Win32Wifi.py#L152
+	/// </remarks>
+	private static int GetChannelWidth(WLAN_BSS_ENTRY bssEntry)
+	{
+		int result = 20;
+		InformationElement? ht_operation = null;
+		InformationElement? vht_operation = null;
+
+		foreach(var field in bssEntry.GetInformationElements())
+		{
+			if (field.Id == 61)
+				ht_operation = field;
+			else if (field.Id == 192)
+				vht_operation = field;
+		}
+
+		if (ht_operation != null)
+		{
+			int secondary_channel_offset = ht_operation[1] & ((1 << 1) | (1 << 0));
+			if (secondary_channel_offset != 0)
+				result = 40;
+		}
+
+		if (vht_operation != null)
+		{
+
+			byte vht_channel_width = vht_operation[0];
+
+			byte channel_center_frequency_segment_1 = vht_operation[2];
+
+			if (vht_channel_width == 1)
+				result = 80;
+
+			if (channel_center_frequency_segment_1 != 0)
+				result = 160;
+		}
+
+		// Convert from MHz to KHz
+		return result * 1000;
+	}
+
+
 	#endregion
 
 	#region Get connection/connection quality

Source/ManagedNativeWifi/Win32/NativeMethod.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Security;
@@ -368,8 +369,28 @@ public struct WLAN_BSS_ENTRY
 		public ushort usCapabilityInformation;
 		public uint ulChCenterFrequency;
 		public WLAN_RATE_SET wlanRateSet;
-		public uint ulIeOffset;
-		public uint ulIeSize;
+
+		/// <summary>
+		/// Information Element data values.
+		/// </summary>
+		/// <remarks>
+		/// This array will contain 2 uint values when marshalled from unsafe memory
+		/// for these fields:
+		/// public uint ulIeOffset;
+		/// public uint ulIeSize;
+		/// The WLAN_AVAILABLE_NETWORK_LIST constructor will read the memory pointed to
+		/// by these values into the array so that the Information Entity values are available
+		/// to the caller.
+		/// See:
+		/// https://learn.microsoft.com/en-us/windows/win32/api/wlanapi/ns-wlanapi-wlan_bss_entry
+		/// </remarks>
+		[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
+		public byte[] informationElements;
+
+		public IEnumerable<InformationElement> GetInformationElements()
+		{
+			return InformationElement.Iterate(informationElements);
+		}
 	}
 
 	public struct WLAN_BSS_LIST
@@ -395,8 +416,72 @@ public WLAN_BSS_LIST(IntPtr ppBssList)
 					+ (itemSize * i) /* Offset for preceding items */);
 
 				wlanBssEntries[i] = Marshal.PtrToStructure<WLAN_BSS_ENTRY>(wlanBssEntry);
+				// Copy the information Entity data
+				var ulIeOffset = BitConverter.ToUInt32(wlanBssEntries[i].informationElements, 0);
+				var ulIeSize = BitConverter.ToUInt32(wlanBssEntries[i].informationElements, 4);
+				var infoPtr = new IntPtr(wlanBssEntry.ToInt64()
+					+ ulIeOffset);
+				if (ulIeSize > 0)
+				{
+					var infoData = new byte[ulIeSize];
+					Marshal.Copy(infoPtr, infoData, 0, infoData.Length);
+					wlanBssEntries[i].informationElements = infoData;
+				}
+				else
+				{
+					wlanBssEntries[i].informationElements = Array.Empty<byte>();
+				}
 			}
 		}
+
+	}
+
+	/// <summary>
+	/// Information element fields look like this
+	/// {id: byte, length: byte, info: byte[lenth]}
+	/// </summary>
+	internal class InformationElement
+	{
+		private byte[] data;
+		private InformationElement(byte[] data, int offset = 0)
+		{
+			this.offset = offset;
+			this.data = data;
+		}
+
+		public static IEnumerable<InformationElement> Iterate(byte[] data)
+		{
+			var field = new InformationElement(data, 0);
+			while (!field.AtEnd())
+			{
+				yield return field.BookMark();
+				field.Next();
+			}
+		}
+
+		private int offset;
+		public byte Id { get => data[offset];  }
+		public byte Length { get => data[offset + 1]; }
+
+		public byte this[int idx]
+		{
+			get => data[offset + 2 + idx];
+		}
+
+		private void Next()
+		{
+			offset += Length + 2;
+		}
+
+		private bool AtEnd()
+		{
+			return data.Length == 0 || offset >= data.Length;
+		}
+
+	    private InformationElement BookMark()
+		{
+		    return new InformationElement (data, offset);
+		}
 	}
 
 	[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]