libosmo-mgcp doesn't use osmo_sock_ API
libosmo-mgcp directly uses the socket API rather than going through the osmo_sock_ helpers, which is a bit odd. Not important, but deserves some clean-up eventually.
It also has it's own RTP implementation and is not using the osmo_rtp_ abstraction based on libortp. However, contrary to the socket helpers, there might be a good reason, such as actually not introducing packet delays due to jitter buffers in the proxy.