void ProcessAccept(SocketAsyncEventArgs e)
{
if (e.SocketError == SocketError.OperationAborted)
{
Stop();
return;
}
try
{
// create SocketAsyncEventArgs for this client
SocketAsyncEventArgs args = new SocketAsyncEventArgs();
args.Completed += IO_Completed;
args.UserToken = new AsyncUserToken();
// assign chunk of big buffer for max performance (see BigBuffer.cs comments)
if (bigBuffer.Assign(args))
{
// Get the socket for the accepted client connection and put it into the
//ReadEventArg object user token
AsyncUserToken userToken = (AsyncUserToken)args.UserToken;
userToken.Socket = e.AcceptSocket;
userToken.ConnectTime = DateTime.Now;
userToken.Remote = e.AcceptSocket.RemoteEndPoint;
userToken.IpAddress = ((IPEndPoint)(e.AcceptSocket.RemoteEndPoint)).Address;
userToken.connectionId = NextConnectionId();
clients[userToken.connectionId] = userToken;
OnClientConnected(userToken);
if (!e.AcceptSocket.ReceiveAsync(args))
{
ProcessReceive(args);
}
}
else
{
Debug.LogError("Server.ProcessAccept: failed to assign buffer.");
}
}
catch (Exception exception)
{
Debug.LogError("Server.ProcessAccept failed: " + exception);
}
StartAccept(e);
}
void CloseClientSocket(SocketAsyncEventArgs e)
{
AsyncUserToken token = (AsyncUserToken)e.UserToken;
clients.TryRemove(token.connectionId, out AsyncUserToken temp);
// close the socket associated with the client
try
{
token?.Socket.Shutdown(SocketShutdown.Both);
}
catch (Exception) { }
token?.Socket.Close();
// call disconnected event
OnClientDisconnected(token);
// free buffer chunk
bigBuffer.Free(e);
}
public void Stop()
{
foreach (KeyValuePair <int, AsyncUserToken> kvp in clients)
{
AsyncUserToken token = kvp.Value;
try
{
token.Socket.Shutdown(SocketShutdown.Both);
OnClientDisconnected(token);
}
catch (Exception) { }
}
try
{
listenSocket?.Shutdown(SocketShutdown.Both);
}
catch (Exception) { }
listenSocket?.Close();
this.Active = false;
clients.Clear();
}
void OnReceiveClientData(AsyncUserToken token, byte[] data)
{
messageQueue.Enqueue(new Message(token.connectionId, EventType.Data, data));
}
// This method is invoked when an asynchronous receive operation completes.
// If the remote host closed the connection, then the socket is closed.
protected override void ProcessReceive(SocketAsyncEventArgs e)
{
try
{
// check if the remote host closed the connection
AsyncUserToken token = (AsyncUserToken)e.UserToken;
if (e.BytesTransferred > 0 && e.SocketError == SocketError.Success)
{
ArraySegment <byte> data = new ArraySegment <byte>(e.Buffer, e.Offset, e.BytesTransferred);
// write it all into our memory stream first
token.buffer.Write(e.Buffer, e.Offset, e.BytesTransferred);
// keep trying headers (we might need to process >1 message)
while (token.buffer.Position >= 4)
{
// we can read a header. so read it.
long bufferSize = token.buffer.Position;
token.buffer.Position = 0;
byte[] header = new byte[4]; // TODO cache
token.buffer.Read(header, 0, header.Length);
int contentSize = Utils.BytesToIntBigEndian(header);
// avoid -1 attacks from hackers
if (contentSize > 0)
{
// enough content to finish the message?
if (bufferSize - token.buffer.Position >= contentSize)
{
// read content
byte[] content = new byte[contentSize];
token.buffer.Read(content, 0, content.Length);
// process message
OnReceiveClientData(token, content);
// read what's left in the buffer. this is valid
// data that we received at some point. can't lose
// it.
byte[] remainder = new byte[bufferSize - token.buffer.Position];
token.buffer.Read(remainder, 0, remainder.Length);
// write it to the beginning of the buffer. this
// sets position to the new true end automatically.
token.buffer.Position = 0;
token.buffer.Write(remainder, 0, remainder.Length);
}
// otherwise we just need to receive more.
else
{
break;
}
}
else
{
CloseClientSocket(e);
Debug.LogWarning("Server.ProcessReceive: received negative contentSize: " + contentSize + ". Maybe an attacker tries to exploit the server?");
}
}
// continue receiving
if (!token.Socket.ReceiveAsync(e))
{
ProcessReceive(e);
}
}
else
{
CloseClientSocket(e);
}
}
catch (Exception exception)
{
CloseClientSocket(e);
Debug.LogError("Server.ProcessReceive failed: " + exception);
}
}
void OnClientDisconnected(AsyncUserToken token)
{
messageQueue.Enqueue(new Message(token.connectionId, EventType.Disconnected, null));
}
