VPN Project

We are required to create some kind of private VPN( a kind of proxy tunnel) between our Wifi IP camera and Ubantu Server. Following is a scenario : 1) Our IP camera always connected with a 3G/4G Wifi hot spot, No Public ip address or any kind of system in between camera and Hotspot. 2) IP camera always have a working Internet connected from SIM based 3G/4G hotspot. 3) Camera will have a Lan IP address and a port number connected with RTMP/RTSP stream. 4) This RTMP/RTSP and http url stream should communicate with our server and we should able to ping this URL and use as a input to our wowza application. 5) We need some kind Of private VPN between wifi IP camera and server to always communicate and stream. Need full source code and a working application installed before closing this project.