async Task HandleClient(IClient client, int pipeBufferSize,
Action <DuplexPipe> pipeCreatedAction,
Func <IPEndPoint, Task <IClient> > createTargetClientFunc,
Action <SmartBuffer, DuplexPipe, IClient, ShadowsocksAddress> targetClientConnectedAction,
CancellationToken cancellationToken)
{
try
{
DuplexPipe pipe = new DuplexPipe(pipeBufferSize, _logger);
pipe.ClientA = client;
pipeCreatedAction(pipe);///////////////////
var readClientResult = await pipe.GetReader(client).Read(cancellationToken);//A. Read target addr (and payload).
if (readClientResult.Result != ReadWriteResult.Succeeded)
{
client.Close(); return;
}
if (readClientResult.Read <= 0)
{
_logger?.LogWarning($"This should not happen. [{client.EndPoint.ToString()}]");
////decrypt failed? available options: 1.leave it. 2.close connection. 3.add to blocklist.
client.Close();
return;
}
var request = readClientResult.Memory;
IPAddress targetIP = IPAddress.Any; //TODO target address check
if (ShadowsocksAddress.TryResolve(request.SignificantMemory, out ShadowsocksAddress ssaddr)) //B. Resolve target addr.
{
_logger?.LogWarning($"Reading target addr. ATYP={ssaddr.ATYP}, client=[{client.EndPoint.ToString()}]");
IPEndPoint ipeTarget = await ssaddr.ToIPEndPoint();
if (IPAddress.Any == ipeTarget.Address || IPAddress.IPv6Any == ipeTarget.Address)//an empty IP.
{
_logger?.LogWarning($"Invalid target addr. client=[{client.EndPoint.ToString()}]");
client.Close();
return;
}
_logger?.LogInformation($"Resolved target address:[{ipeTarget.ToString()}]. Connecting...");
IClient targetClient = await createTargetClientFunc(ipeTarget); //C. Connect target ///////////////////////////////
if (null == targetClient) //connect target failed.
{
_logger?.LogInformation($"Unable to connect target [{ipeTarget.ToString()}]. client=[{client.EndPoint.ToString()}]");
client.Close();
return;
}
_logger?.LogInformation($"Connected to [{ipeTarget.ToString()}]");
targetClientConnectedAction(request, pipe, targetClient, ssaddr);////////////////////////////////
_logger?.LogInformation($"Start piping...");
PipeClient(pipe, cancellationToken);//D. start piping.
}
else//invalid socks5 addr
{
_logger?.LogWarning($"Resolve target addr failed. client=[{client.EndPoint.ToString()}]");
client.Close();
return;
}
await Task.CompletedTask;
}
catch (Exception ex)
{
_logger?.LogError(ex, "HandleClient");
}
}