README

In order to reach the devices that are connected behind NAT, the cwmp protocol introduces alternative method of executing Connection Request via NAT based on STUN. The stund is an implementation of STUN functionality that performs this feature.

Configuration File

The stund UCI configuration is located in '/etc/config/stun' and contains only one section stun:

config stun 'stun'
	option enable '0'
	option username 'stun'
	option password 'stun'
	option server_address 'stun.l.google.com'
	option server_port '19302'
	option min_keepalive '30'
	option max_keepalive '3600'
	option client_port 7547
	option log_level '1'

stun section

It defines the stun section configuration (like username, password, etc...). The possible options for stun section are listed in the table below.

Name	Type	Description
enable	boolean	if set to 1, the STUN client will be enabled.
username	string	The STUN username to be used in Binding Requests.
password	string	The STUN Password to be used in computing the MESSAGE-INTEGRITY.
server_address	string	The host name or IP address of the STUN server to send Binding Requests.
server_port	integer	The port number of the STUN server to send Binding Requests.
min_keepalive	integer	The minimum period that STUN Binding Requests must be sent by the CPE for the purpose of maintaining the binding in the Gateway.
max_keepalive	integer	The maximum period that STUN Binding Requests must be sent by the CPE for the purpose of maintaining the binding in the Gateway.
client_port	integer	The client source port of the STUN UDP binding.
log_level	integer	The log type to use, by default it is set to 'INFO'. The possible types are 'EMERG', 'ALERT', 'CRITIC' ,'ERROR', 'WARNING', 'NOTICE', 'INFO' and 'DEBUG'.

Dependencies

To successfully build stund, the following libraries are needed:

Dependency	Link	License
libuci	https://git.openwrt.org/project/uci.git	LGPL 2.1
libubox	https://git.openwrt.org/project/libubox.git	BSD
libubus	https://git.openwrt.org/project/ubus.git	LGPL 2.1
libjson-c	https://s3.amazonaws.com/json-c_releases	MIT
libopenssl	http://ftp.fi.muni.cz/pub/openssl/source/	OpenSSL