private void ProcessPacket(SessionPacket packet, ref ConnectionState state)
{
if (packet is SessionRequestPacket && m_transport == SMBTransportType.NetBiosOverTCP)
{
PositiveSessionResponsePacket response = new PositiveSessionResponsePacket();
state.SendQueue.Enqueue(response);
}
else if (packet is SessionKeepAlivePacket && m_transport == SMBTransportType.NetBiosOverTCP)
{
// [RFC 1001] NetBIOS session keep alives do not require a response from the NetBIOS peer
}
else if (packet is SessionMessagePacket)
{
// Note: To be compatible with SMB2 specifications, we must accept SMB_COM_NEGOTIATE.
// We will disconnect the connection if m_enableSMB1 == false and the client does not support SMB2.
bool acceptSMB1 = (state.Dialect == SMBDialect.NotSet || state.Dialect == SMBDialect.NTLM012);
bool acceptSMB2 = (m_enableSMB2 && (state.Dialect == SMBDialect.NotSet || state.Dialect == SMBDialect.SMB202 || state.Dialect == SMBDialect.SMB210));
if (SMB1Header.IsValidSMB1Header(packet.Trailer))
{
if (!acceptSMB1)
{
state.LogToServer(Severity.Verbose, "Rejected SMB1 message");
state.ClientSocket.Close();
return;
}
SMB1Message message = null;
try
{
message = SMB1Message.GetSMB1Message(packet.Trailer);
}
catch (Exception ex)
{
state.LogToServer(Severity.Warning, "Invalid SMB1 message: " + ex.Message);
state.ClientSocket.Close();
return;
}
state.LogToServer(Severity.Verbose, "SMB1 message received: {0} requests, First request: {1}, Packet length: {2}", message.Commands.Count, message.Commands[0].CommandName.ToString(), packet.Length);
if (state.Dialect == SMBDialect.NotSet && m_enableSMB2)
{
// Check if the client supports SMB 2
List <string> smb2Dialects = SMB2.NegotiateHelper.FindSMB2Dialects(message);
if (smb2Dialects.Count > 0)
{
SMB2Command response = SMB2.NegotiateHelper.GetNegotiateResponse(smb2Dialects, m_securityProvider, state, m_serverGuid, m_serverStartTime);
if (state.Dialect != SMBDialect.NotSet)
{
state = new SMB2ConnectionState(state);
m_connectionManager.AddConnection(state);
}
EnqueueResponse(state, response);
return;
}
}
if (m_enableSMB1)
{
ProcessSMB1Message(message, ref state);
}
else
{
// [MS-SMB2] 3.3.5.3.2 If the string is not present in the dialect list and the server does not implement SMB,
// the server MUST disconnect the connection [..] without sending a response.
state.LogToServer(Severity.Verbose, "Rejected SMB1 message");
state.ClientSocket.Close();
}
}
else if (SMB2Header.IsValidSMB2Header(packet.Trailer))
{
if (!acceptSMB2)
{
state.LogToServer(Severity.Verbose, "Rejected SMB2 message");
state.ClientSocket.Close();
return;
}
List <SMB2Command> requestChain;
try
{
requestChain = SMB2Command.ReadRequestChain(packet.Trailer, 0);
}
catch (Exception ex)
{
state.LogToServer(Severity.Warning, "Invalid SMB2 request chain: " + ex.Message);
state.ClientSocket.Close();
return;
}
state.LogToServer(Severity.Verbose, "SMB2 request chain received: {0} requests, First request: {1}, Packet length: {2}", requestChain.Count, requestChain[0].CommandName.ToString(), packet.Length);
ProcessSMB2RequestChain(requestChain, ref state);
}
else
{
state.LogToServer(Severity.Warning, "Invalid SMB message");
state.ClientSocket.Close();
}
}
else
{
state.LogToServer(Severity.Warning, "Invalid NetBIOS packet");
state.ClientSocket.Close();
return;
}
}
// This method accepts new connections
private void ConnectRequestCallback(IAsyncResult ar)
{
Socket listenerSocket = (Socket)ar.AsyncState;
Socket clientSocket;
try
{
clientSocket = listenerSocket.EndAccept(ar);
}
catch (ObjectDisposedException)
{
return;
}
catch (SocketException ex)
{
const int WSAECONNRESET = 10054; // The client may have closed the connection before we start to process the connection request.
const int WSAETIMEDOUT = 10060; // The client did not properly respond after a period of time.
// When we get WSAECONNRESET or WSAETIMEDOUT, we have to continue to accept other connection requests.
// See http://stackoverflow.com/questions/7704417/socket-endaccept-error-10054
if (ex.ErrorCode == WSAECONNRESET || ex.ErrorCode == WSAETIMEDOUT)
{
listenerSocket.BeginAccept(ConnectRequestCallback, listenerSocket);
}
Log(Severity.Debug, "Connection request error {0}", ex.ErrorCode);
return;
}
// Windows will set the TCP keepalive timeout to 120 seconds for an SMB connection
SocketUtils.SetKeepAlive(clientSocket, TimeSpan.FromMinutes(2));
// Disable the Nagle Algorithm for this tcp socket:
clientSocket.NoDelay = true;
IPEndPoint clientEndPoint = (IPEndPoint)clientSocket.RemoteEndPoint;
EventHandler <ConnectionRequestEventArgs> handler = ConnectionRequested;
bool acceptConnection = true;
if (handler != null)
{
ConnectionRequestEventArgs connectionRequestArgs = new ConnectionRequestEventArgs(clientEndPoint);
handler(this, connectionRequestArgs);
acceptConnection = connectionRequestArgs.Accept;
}
if (acceptConnection)
{
ConnectionState state = new ConnectionState(clientSocket, clientEndPoint, Log);
state.LogToServer(Severity.Verbose, "New connection request accepted");
Thread senderThread = new Thread(delegate()
{
ProcessSendQueue(state);
});
senderThread.IsBackground = true;
senderThread.Start();
try
{
// Direct TCP transport packet is actually an NBT Session Message Packet,
// So in either case (NetBios over TCP or Direct TCP Transport) we will receive an NBT packet.
clientSocket.BeginReceive(state.ReceiveBuffer.Buffer, state.ReceiveBuffer.WriteOffset, state.ReceiveBuffer.AvailableLength, 0, ReceiveCallback, state);
}
catch (ObjectDisposedException)
{
}
catch (SocketException)
{
}
}
else
{
Log(Severity.Verbose, "[{0}:{1}] New connection request rejected", clientEndPoint.Address, clientEndPoint.Port);
clientSocket.Close();
}
listenerSocket.BeginAccept(ConnectRequestCallback, listenerSocket);
}
private void ReceiveCallback(IAsyncResult result)
{
ConnectionState state = (ConnectionState)result.AsyncState;
Socket clientSocket = state.ClientSocket;
if (!m_listening)
{
clientSocket.Close();
return;
}
int numberOfBytesReceived;
try
{
numberOfBytesReceived = clientSocket.EndReceive(result);
}
catch (ObjectDisposedException)
{
state.LogToServer(Severity.Debug, "The connection was terminated");
m_connectionManager.ReleaseConnection(state);
return;
}
catch (SocketException ex)
{
const int WSAECONNRESET = 10054;
if (ex.ErrorCode == WSAECONNRESET)
{
state.LogToServer(Severity.Debug, "The connection was forcibly closed by the remote host");
}
else
{
state.LogToServer(Severity.Debug, "The connection was terminated, Socket error code: {0}", ex.ErrorCode);
}
m_connectionManager.ReleaseConnection(state);
return;
}
if (numberOfBytesReceived == 0)
{
state.LogToServer(Severity.Debug, "The client closed the connection");
m_connectionManager.ReleaseConnection(state);
return;
}
state.UpdateLastReceiveDT();
NBTConnectionReceiveBuffer receiveBuffer = state.ReceiveBuffer;
receiveBuffer.SetNumberOfBytesReceived(numberOfBytesReceived);
ProcessConnectionBuffer(ref state);
if (clientSocket.Connected)
{
try
{
clientSocket.BeginReceive(state.ReceiveBuffer.Buffer, state.ReceiveBuffer.WriteOffset, state.ReceiveBuffer.AvailableLength, 0, ReceiveCallback, state);
}
catch (ObjectDisposedException)
{
m_connectionManager.ReleaseConnection(state);
}
catch (SocketException)
{
m_connectionManager.ReleaseConnection(state);
}
}
}
private void ReceiveCallback(object sender, SocketAsyncEventArgs result)
{
ConnectionState state = (ConnectionState)result.UserToken;
Socket clientSocket = state.ClientSocket;
if (!m_listening)
{
clientSocket.Dispose();
return;
}
int numberOfBytesReceived;
try
{
numberOfBytesReceived = result.BytesTransferred;
}
catch (ObjectDisposedException)
{
state.LogToServer(Severity.Debug, "The connection was terminated");
m_connectionManager.ReleaseConnection(state);
return;
}
catch (SocketException ex)
{
///const int WSAECONNRESET = 10054;
if (ex.SocketErrorCode == SocketError.ConnectionReset)
{
state.LogToServer(Severity.Debug, "The connection was forcibly closed by the remote host");
}
else
{
state.LogToServer(Severity.Debug, "The connection was terminated, Socket error code: {0}", ex.SocketErrorCode);
}
m_connectionManager.ReleaseConnection(state);
return;
}
if (numberOfBytesReceived == 0)
{
state.LogToServer(Severity.Debug, "The client closed the connection");
m_connectionManager.ReleaseConnection(state);
return;
}
state.UpdateLastReceiveDT();
NBTConnectionReceiveBuffer receiveBuffer = state.ReceiveBuffer;
receiveBuffer.SetNumberOfBytesReceived(numberOfBytesReceived);
ProcessConnectionBuffer(ref state);
if (clientSocket.Connected)
{
try
{
SocketAsyncEventArgs args = new SocketAsyncEventArgs();
args.SetBuffer(state.ReceiveBuffer.Buffer, state.ReceiveBuffer.WriteOffset, state.ReceiveBuffer.AvailableLength);
args.Completed += ReceiveCallback;
args.UserToken = state;
//m_currentAsyncResult =
if (!clientSocket.ReceiveAsync(args))
{
ReceiveCallback(sender, args);
}
}
catch (ObjectDisposedException)
{
m_connectionManager.ReleaseConnection(state);
}
catch (SocketException)
{
m_connectionManager.ReleaseConnection(state);
}
}
}
