Implementing Local Peer Discovery receiving

LocalPeerDiscovery.cs

@@ -0,0 +1,118 @@
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+
+namespace System.Net.Torrent
+{
+	public class LocalPeerDiscovery
+	{
+		private const string lpdMulticastAddress = "239.192.152.143";
+		private const int lpdMulticastPort = 6771;
+
+		private readonly Socket udpReaderSocket;
+
+		private Thread thread;
+		private bool _killSwitch;
+
+		public delegate void NewPeerCB(IPAddress address, int port, String infoHash);
+
+		public event NewPeerCB NewPeer;
+
+		public LocalPeerDiscovery()
+		{
+			udpReaderSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
+		}
+
+		public LocalPeerDiscovery(Socket socket)
+		{
+			if (socket == null)
+			{
+				throw new ArgumentNullException("socket");
+			}
+
+			if (socket.ProtocolType != ProtocolType.Udp)
+			{
+				throw new ArgumentException("socket must be a UDP socket", "socket");
+			}
+
+			if (socket.SocketType != SocketType.Dgram)
+			{
+				throw new ArgumentException("socket must be a datagram socket", "socket");
+			}
+
+			udpReaderSocket = socket;
+		}
+
+		public void Open()
+		{
+			udpReaderSocket.ExclusiveAddressUse = false;
+			udpReaderSocket.SetSocketOption(SocketOptionLevel.Socket,
+				SocketOptionName.ReuseAddress,
+				true);
+
+			IPAddress address = IPAddress.Parse(lpdMulticastAddress);
+
+			var endPoint = new IPEndPoint(IPAddress.Any, lpdMulticastPort);
+			udpReaderSocket.Bind(endPoint);
+
+			udpReaderSocket.SetSocketOption(SocketOptionLevel.IP, 
+				SocketOptionName.AddMembership, 
+				new MulticastOption(address, IPAddress.Any));
+
+			thread = new Thread(Process);
+			thread.Start();
+		}
+
+		public void Close()
+		{
+			_killSwitch = true;
+			thread.Abort();
+
+			udpReaderSocket.Close();
+		}
+
+		private void Process()
+		{
+			byte[] buffer = new byte[200];
+			while (!_killSwitch)
+			{
+				EndPoint endPoint = new IPEndPoint(0,0);
+				udpReaderSocket.ReceiveFrom(buffer, ref endPoint);
+
+				IPAddress remoteAddress = ((IPEndPoint) endPoint).Address;
+				int remotePort = 0;
+				string remoteHash = "";
+
+				String packet = Encoding.ASCII.GetString(buffer).Trim();
+
+				if (!packet.StartsWith("BT-SEARCH"))
+				{
+					continue;
+				}
+
+				String[] packetLines = packet.Split('\n');
+
+				foreach (string line in packetLines)
+				{
+					if (line.StartsWith("Port:"))
+					{
+						string portStr = line.Substring(5).Trim();
+						int.TryParse(portStr, out remotePort);
+					}
+					if (line.StartsWith("Infohash:"))
+					{
+						remoteHash = line.Substring(10, 40);
+					}
+				}
+
+				if (!String.IsNullOrEmpty(remoteHash) && remotePort != 0)
+				{
+					if (NewPeer != null)
+					{
+						NewPeer(remoteAddress, remotePort, remoteHash);
+					}
+				}
+			}
+		}
+	}
+}

Metadata.cs

@@ -219,7 +219,7 @@ public bool Load(Stream stream)
                     BString pieces = (BString)infoDict["pieces"];
                     for (int x = 0; x < pieces.ByteValue.Length; x += 20)
                     {
-                        byte[] hash = Utils.GetBytes(pieces.ByteValue, x, 20);
+                        byte[] hash = pieces.ByteValue.GetBytes(x, 20);
                         PieceHashes.Add(hash);
                     }
                 }

System.Net.Torrent.csproj

@@ -49,6 +49,7 @@
     <Compile Include="Extensions\UTPeerExchange.cs" />
     <Compile Include="HTTPTrackerClient.cs" />
     <Compile Include="IO\WireIO.Udp.cs" />
+    <Compile Include="LocalPeerDiscovery.cs" />
     <Compile Include="ProtocolExtensions\IBTExtension.cs" />
     <Compile Include="IPeerCommand.cs" />
     <Compile Include="IProtocolExtension.cs" />