Re: [PATCH] tcpserver: transparent tcp proxying support using Linux netfilter + nc

Denis Vlasenko <[email protected]> wrote:
> I'm not really sure where to send this.

<URL:http://www.superscript.com/lists.html#ucspi>

> With this really small patch you can proxy any TCP
> service.

IIUC, no patch is needed for that.  You can already get the same
effect by running multiple tcpservers on separate ports.  Each one
would be configured by hand to proxy to a different address/port,
instead of getting that information from the socket.

Another option would be to write a wrapper to be invoked by tcpserver
that would inspect the socket, set the environment variables, and exec
the rest of its command line.

> Theory of operation: upon accept, tcpserver queries
> Linux kernel about 'original' (ie, before -j REDIRECT)
> IP and port numbers and places them into
> TCPORIGDSTIP and TCPORIGDSTPORT.

To be consistent, s/DST/LOCAL/g.

> +#include <linux/netfilter_ipv4.h>

It's doubtful Dan would accept such a platform-specific patch.


paul