Adding Ethernet PHY to Esp8266 firmware to build a Ethernet MavLink bridge.

Hello , 
This is not exactly a issue with the MavEsp firmware . 
Can someone help me with adding a Ethernet PHY layer and necessary changes in the firmware code required to build a Ethernet Mavlink bridge ? 
I have got sources to build a Ethernet breakout to Esp8266 hardware .  
Any help with this would be wonderful as i am working on telemetry connection through Ethernet to Ground computer. 