Problems with Starksoft.Net.Proxy for SOCKS and bittorrent

Question

I'm using C# to make a bittorrent application with MonoTorrent. The application is somewhat mature, but I'm adding SOCKSv5 proxy support. I've found Starksoft.Net.Proxy to handle the proxy part. However, I'm having some trouble.

I got a BTGuard account for testing with. When I connect (providing username and password and such), I get this error:

Starksoft.Net.Proxy.ProxyException: Connection to proxy host 63.142.161.35 on port 1025 failed. ---> Starksoft.Net.Proxy.ProxyException: The the connection is not allowed by proxy destination rule set concerning destination host 195.122.253.23 port number 11523.  The destination reported the host as 0.0.0.0 port -16676.
   at Starksoft.Net.Proxy.Socks5ProxyClient.HandleProxyCommandError(Byte[] response, String destinationHost, Int32 destinationPort)
   at Starksoft.Net.Proxy.Socks5ProxyClient.SendCommand(Byte command, String destinationHost, Int32 destinationPort)
   at Starksoft.Net.Proxy.Socks5ProxyClient.CreateConnection(String destinationHost, Int32 destinationPort)
   --- End of inner exception stack trace ---
   at Starksoft.Net.Proxy.Socks5ProxyClient.CreateConnection(String destinationHost, Int32 destinationPort)
   at Starksoft.Net.Proxy.Socks5ProxyClient.CreateConnectionAsync_DoWork(Object sender, DoWorkEventArgs e)

Which is weird. I have no idea what causes this. I read through the Starksoft code and it seems reasonably in-line with the SOCKS RFC.

Here's the code I'm using to connect to the proxy via Starksoft.Net.Proxy. The stack trace above comes from e.Error on line 133.

Answer 1

I found the issue. Here's the part where Starksoft.Net.Proxy prepares and then discards the data for the username/password exchange.

I fixed it by updating to Biko, but it required some tweaking to get working right. Should be simple for anyone who finds this problem later to deal with.

Alternatively, just grab the source of the broken version and stick some code in to send the data and receive the confirmation.