Simple filter to mangle ssh data stream to fool moronic DPI tools used to
prevent ssh connections. Use it in the script specified in .ssh/config
ProxyCommand, like this:

  ssh-invert | nc <ssh-server> <ssh-invert-port> | ssh-invert

On the other side at the ssh-server use the same wrapper as a script for
e.g. xinetd:

    service daap
    {
            disable         = no
            server          = /usr/bin/ssh-invert.sh
            socket_type     = stream
            protocol        = tcp
            user            = ssh-invert
            wait            = no
    }

and /usr/bin/ssh-invert.sh looking like

  ssh-invert | nc 127.0.0.1 22 | ssh-invert