Move common magic checking code into ptr2mpf() function, otherwise we might deref some random pointer.
Move common magic checking code into ptr2mpf() function, otherwise
we might deref some random pointer.

synety-jdebp/rtpproxy,sippy/rtpproxy,synety-jdebp/rtpproxy,jevonearth/rtpproxy,jevonearth/rtpproxy,synety-jdebp/rtpproxy,dsanders11/rtpproxy,jevonearth/rtpproxy,sippy/rtpproxy,sippy/rtpproxy,dsanders11/rtpproxy,jevonearth/rtpproxy,dsanders11/rtpproxy,synety-jdebp/rtpproxy