/// <summary>
/// Handle an incoming POP3 connection, from connection to completion.
/// </summary>
/// <param name="parameters">Pop3ProxyConnectionArguments object containing all parameters for this connection.</param>
private void ProcessConnection(object parameters)
{
// Cast the passed-in parameters back to their original objects.
Pop3ProxyConnectionArguments arguments = (Pop3ProxyConnectionArguments)parameters;
try
{
TcpClient client = arguments.TcpClient;
Stream clientStream = client.GetStream();
// Capture the client's IP information.
PropertyInfo pi = clientStream.GetType().GetProperty("Socket", BindingFlags.NonPublic | BindingFlags.Instance);
string ip = ((Socket)pi.GetValue(clientStream, null)).RemoteEndPoint.ToString();
if (ip.IndexOf(":") > -1)
{
ip = ip.Substring(0, ip.IndexOf(":"));
}
// If the IP address range filter contains the localhost entry 0.0.0.0, check if the client IP is a local address and update it to 0.0.0.0 if so.
if (arguments.AcceptedIPs.IndexOf("0.0.0.0") > -1)
{
if (ip == "127.0.0.1")
{
ip = "0.0.0.0";
}
else
{
IPHostEntry hostEntry = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress hostIP in hostEntry.AddressList)
{
if (hostIP.ToString() == ip)
{
ip = "0.0.0.0";
break;
}
}
}
}
// Validate that the IP address is within an accepted range.
if (!ProxyFunctions.ValidateIP(arguments.AcceptedIPs, ip))
{
ProxyFunctions.Log(LogWriter, SessionId, arguments.ConnectionId, "Connection rejected from {" + ip + "} due to its IP address.", Proxy.LogLevel.Warning, LogLevel);
Functions.SendStreamString(clientStream, new byte[Constants.SMALLBUFFERSIZE], "500 IP address [" + ip + "] rejected.\r\n");
if (clientStream != null)
{
clientStream.Dispose();
}
if (client != null)
{
client.Close();
}
return;
}
ProxyFunctions.Log(LogWriter, SessionId, arguments.ConnectionId, "New connection established from {" + ip + "}.", Proxy.LogLevel.Information, LogLevel);
// If supported, upgrade the session's security through a TLS handshake.
if (arguments.LocalEnableSsl)
{
ProxyFunctions.Log(LogWriter, SessionId, arguments.ConnectionId, "Starting local TLS/SSL protection for {" + ip + "}.", Proxy.LogLevel.Information, LogLevel);
clientStream = new SslStream(clientStream);
((SslStream)clientStream).AuthenticateAsServer(arguments.Certificate);
}
// Connect to the remote server.
TcpClient remoteServerClient = new TcpClient(arguments.RemoteServerHostName, arguments.RemoteServerPort);
Stream remoteServerStream = remoteServerClient.GetStream();
// If supported, upgrade the session's security through a TLS handshake.
if (arguments.RemoteServerEnableSsl)
{
ProxyFunctions.Log(LogWriter, SessionId, arguments.ConnectionId, "Starting remote TLS/SSL protection with {" + arguments.RemoteServerHostName + "}.", Proxy.LogLevel.Information, LogLevel);
remoteServerStream = new SslStream(remoteServerStream);
((SslStream)remoteServerStream).AuthenticateAsClient(arguments.RemoteServerHostName);
}
// Relay server data to the client.
TransmitArguments remoteServerToClientArguments = new TransmitArguments();
remoteServerToClientArguments.ClientStream = remoteServerStream;
remoteServerToClientArguments.RemoteServerStream = clientStream;
remoteServerToClientArguments.IsClient = false;
remoteServerToClientArguments.ConnectionId = ConnectionId.ToString();
remoteServerToClientArguments.InstanceId = arguments.InstanceId;
remoteServerToClientArguments.DebugMode = arguments.DebugMode;
remoteServerToClientArguments.IPAddress = ip;
remoteServerToClientArguments.ExportDirectory = arguments.ExportDirectory;
Thread remoteServerToClientThread = new Thread(new ParameterizedThreadStart(RelayData));
remoteServerToClientThread.Name = "OpaqueMail POP3 Proxy Server to Client";
remoteServerToClientThread.Start(remoteServerToClientArguments);
// Relay client data to the remote server.
TransmitArguments clientToRemoteServerArguments = new TransmitArguments();
clientToRemoteServerArguments.ClientStream = clientStream;
clientToRemoteServerArguments.RemoteServerStream = remoteServerStream;
clientToRemoteServerArguments.IsClient = true;
clientToRemoteServerArguments.ConnectionId = ConnectionId.ToString();
clientToRemoteServerArguments.InstanceId = arguments.InstanceId;
clientToRemoteServerArguments.DebugMode = arguments.DebugMode;
clientToRemoteServerArguments.IPAddress = ip;
clientToRemoteServerArguments.Credential = arguments.RemoteServerCredential;
Thread clientToRemoteServerThread = new Thread(new ParameterizedThreadStart(RelayData));
clientToRemoteServerThread.Name = "OpaqueMail POP3 Proxy Client to Server";
clientToRemoteServerThread.Start(clientToRemoteServerArguments);
}
catch (SocketException ex)
{
if (arguments.DebugMode || System.Diagnostics.Debugger.IsAttached)
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception communicating with {" + arguments.RemoteServerHostName + "} on port {" + arguments.RemoteServerPort + "}: " + ex.ToString(), Proxy.LogLevel.Error, LogLevel);
}
else
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception communicating with {" + arguments.RemoteServerHostName + "} on port {" + arguments.RemoteServerPort + "}: " + ex.Message, Proxy.LogLevel.Error, LogLevel);
}
}
catch (Exception ex)
{
if (arguments.DebugMode || System.Diagnostics.Debugger.IsAttached)
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception: " + ex.ToString(), Proxy.LogLevel.Error, LogLevel);
}
else
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception: " + ex.Message, Proxy.LogLevel.Error, LogLevel);
}
}
}
