Get MAC address of host inside a docker container

I'm looking for an efficient way to get the MAC address of host inside a docker container. The docker container will not run with host network enabled and I don't want to supply the MAC address as an ENV variable. There would be a program ( preferably C++ or Python code ) that runs inside the docker container. The program would write the MAC address to a file. The MAC address will be the true MAC address of the host's network device. The docker will have a Ubuntu operating system. Any ways of achieving this?