[jdev] SOCKS5 Bytestream File Transfer problem

[Anthony Ortiz]

Hmmm... okay, so I took your suggestion regarding the handshake. I
change my code to do the following now  :

[pseudo code]
Set Socks5Proxy to 192.168.1.100:8010
Set Socks5Proxy to direct connect to 192.168.1.100 and no-authentication
Open a Socks5Connection to 192.168.1.100:8010

So far so good, everything works well up to this point. I then send a
SOCKS request as described in the protocol and send it
[http://www.faqs.org/rfcs/rfc1928.html]. It sends just fine but then I
get a weird response back from the initiator. Instead of getting a
response packet I get the following :

000000000

*sigh*... 9 zeros... nothing at all like the request packet that i was
expecting according to the protocol. Now I know I'm definitely doing
something wrong. How were you guys able to implement this based on
just the JEP-0065?? Am I really that dense or is there another
document I should be looking at??

:(((

Anyway, thanks for the assist so far... it's gotta be something stupid
in the way I'm implementing this but I can't see it for the life of
me...

Anthony

On Fri, 25 Feb 2005 15:38:32 -0800, Justin Karneges
<justin-keyword-jabber.093179 at affinix.com> wrote:
> On Friday 25 February 2005 02:50 pm, Anthony Ortiz wrote:
> > [1] If the Target is willing to accept the bytestream, it MUST attempt
> > to open a standard TCP socket on the network address of the StreamHost
> > communicated by the Initiator. If the Initiator provides more than one
> > StreamHost, the Target SHOULD try to connect to them in the order they
> > occur.
> >
> > ...
> >
> > [3] If the Target is able to open a TCP socket on a StreamHost, it
> > MUST utilize the SOCKS5 protocol specified in RFC 1928 [7] to
> > establish the connection with the StreamHost. In accordance with the
> > SOCKS5 RFC, the Target MAY have to authenticate in order to use the
> > proxy. However, any authentication required is beyond the scope of
> > this JEP.
> [snip]
> > At first, my understanding was that I should open a standard TCP
> > connection to the streamhost(s) (192.168.1.100:8010 in this particular
> > case) in order to test if the connnection could be made (as per the
> > paragraph [1]). I did this at first and that part worked fine & was
> > able to connect, but then I stripped that code out because it seemed
> > redundant after I read paragraph [3] which states that I will have to
> > open a SOCKS5 connection to that streamhost anyway, and in the
> 
> Maybe it's not fully clear (and I'm simply reading from the quoted text you
> provided), but what [3] is intended to mean is that you would perform the
> SOCKS5 protocol over the established TCP connection from [1].  There are not
> two connections.  I suppose it is spelled out in steps like this in case
> you're writing your own SOCKS protocol code.  If you're using a SOCKS library
> to perform the connection, which will both create the TCP connection as well
> as negotiate the SOCKS5 protocol over it, then that's all you need to use.
> 
> > Proxy.setDefaultProxy(host, port); // sets SOCKS5 proxy to be
> > 192.168.1.100:8010
> >
> [snip]
> > So this tells me that the actual SOCKS5 host to connect to is the SHA1
> > hash of sid + from + to and that the port is 0. That is why I have the
> > following line in my code :
> 
> Well, just to ensure our terminology is clear, the SOCKS5 host (or proxy, or
> server, or whatever) is 192.168.1.100.  The destination (or DST) host, ie the
> one that you'll ask the SOCKS5 host to bridge you to, is the hash.
> 
> Of course, you're aware that the hash is not a real host, and that the SOCKS5
> host (in this example, Psi) is not actually going to perform an outbound
> connection to the DST as a result.  It is simply used as a handshake.
> 
> > Socket ss = new SocksSocket(SocksHost, 0);
> 
> My confusion with this line of code is that I don't see how it relates to the
> Proxy object.  In other words, how does the SocksSocket know what SOCKS5 host
> to connect to?  I know nothing about the library you're using though, so
> maybe the Proxy object interfaces with some global settings in the
> background, and SocksSocket draws from that.
> 
> It could be that you understand the protocol, and are coding with the right
> intent, but simply coding it wrong. ;-)
> 
> > p.s. btw Justin... great work on the PSI client!
> 
> Glad you like it. :)
> 
> Have fun,
> -Justin
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