protected override void Decode(IChannelHandlerContext context, IByteBuffer input, List <object> output)
{
try
{
switch (State)
{
case Socks4ServerDecoderState.Start:
var version = input.ReadByte();
if (version != (byte)SocksVersion.Socks4A)
{
throw new DecoderException("unsupported protocol version: " + version);
}
_type = Socks4CommandType.ValueOf(input.ReadByte());
_dstPort = input.ReadUnsignedShort();
_dstAddr = new IPAddress(input.ReadInt()).ToString();
Checkpoint(Socks4ServerDecoderState.ReadUserid);
break;
case Socks4ServerDecoderState.ReadUserid:
_userId = ReadString("userid", input);
Checkpoint(Socks4ServerDecoderState.ReadDomain);
break;
case Socks4ServerDecoderState.ReadDomain:
// Check for Socks4a protocol marker 0.0.0.x
if (_dstAddr != "0.0.0.0" && _dstAddr.StartsWith("0.0.0."))
{
_dstAddr = ReadString("dstAddr", input);
}
output.Add(new DefaultSocks4CommandRequest(_type, _dstAddr, _dstPort, _userId));
Checkpoint(Socks4ServerDecoderState.Success);
break;
case Socks4ServerDecoderState.Success:
var readableBytes = ActualReadableBytes;
if (readableBytes > 0)
{
output.Add(input.ReadRetainedSlice(readableBytes));
}
break;
case Socks4ServerDecoderState.Failure:
input.SkipBytes(ActualReadableBytes);
break;
}
}
catch (Exception e)
{
Fail(output, e);
}
}
/**
* Creates a new instance.
*
* @param type the type of the request
* @param dstAddr the {@code DSTIP} field of the request
* @param dstPort the {@code DSTPORT} field of the request
*/
/**
* Creates a new instance.
*
* @param type the type of the request
* @param dstAddr the {@code DSTIP} field of the request
* @param dstPort the {@code DSTPORT} field of the request
* @param userId the {@code USERID} field of the request
*/
public DefaultSocks4CommandRequest(Socks4CommandType type, string dstAddr, int dstPort, string userId = "")
{
if (dstPort <= 0 || dstPort >= 65536)
{
throw new ArgumentException("dstPort: " + dstPort + " (expected: 1~65535)");
}
UserId = userId;
Type = type;
DstAddr = Idn.GetAscii(dstAddr);
DstPort = dstPort;
}
