The udp_tunnel module implements a "Line Protocol". When this protocol is chosen by a Line, it sends data received via UDP out on the Line. It sends data received on the Line out via UDP when it receives <Enter> or fills its 80 character buffer.
As delivered in the SDK, the module listens for UDP packets on interface wlan0 addressed to the LOCAL_PORT 10001. When the first packet is received, it sends "Connected" to the Line. Subsequently it listens to the line for data to send out via UDP. The #define REMOTE_ADDRESS may be "ap0", "eth0", or "wlan0" to operate in this listening mode.
Alternately, you can change the #define REMOTE_ADDRESS to either an IP address or a host name to operate in a connect mode. In this case you must also set the #define REMOTE_PORT. When the interface is established and resolves the name or address, it sends "Connected" to the Line.
Build it from project "udpTunnelDemo".