private async Task AuthenticateAsync(Stream s)
{
await _negotiationRequest.WriteToAsync(s);
await s.FlushAsync();
SocksProxyNegotiationReply negotiationReply = await SocksProxyNegotiationReply.ReadRequestAsync(s);
if (!negotiationReply.IsVersionSupported)
{
throw new SocksProxyException("Socks version 5 is not supported by the proxy server.");
}
switch (negotiationReply.Method)
{
case SocksProxyAuthenticationMethod.UsernamePassword:
if (_authRequest == null)
{
throw new SocksProxyAuthenticationFailedException("Socks proxy server requires authentication.");
}
await _authRequest.WriteToAsync(s);
await s.FlushAsync();
SocksProxyAuthenticationReply authenticationReply = await SocksProxyAuthenticationReply.ReadRequestAsync(s);
if (!authenticationReply.IsVersionSupported)
{
throw new SocksProxyAuthenticationFailedException("Socks proxy server does not support username/password method version 1.");
}
if (authenticationReply.Status != SocksProxyAuthenticationStatus.Success)
{
throw new SocksProxyAuthenticationFailedException("Socks proxy server authentication failed: invalid username or password.");
}
break;
case SocksProxyAuthenticationMethod.NoAuthenticationRequired:
break;
case SocksProxyAuthenticationMethod.NoAcceptableMethods:
if (_authRequest == null)
{
throw new SocksProxyAuthenticationFailedException("Socks proxy server requires authentication.");
}
else
{
throw new SocksProxyAuthenticationFailedException("Socks proxy server does not support username/password method.");
}
default:
throw new SocksProxyException("Socks proxy server returned unknown method.");
}
}
