title: How to calculate PRF in OpenSSL?
body: <p>I'm developing a EAP-TLS server using OpenSSL. I need to derive key material from TLS session as described in RFC5216. </p>
  
  <p>Key_Material = TLS-PRF-128(master_secret, "client EAP encryption", client.random || server.random)</p>
  
  <p>I can get master secret in TLS connection by visit SSL_SESSION->master_key, but how could I calculate PRF by OpenSSL?</p>