Sounds like a mix of "hungry" and "lacking in handling". Always remember to wash your hands after handling their food items, and set asside time to interact with the snake outside of feeding times. Essentially, the mix of possible rat scent on your hands and a time with you only opening the cage to feed him has set the snake into what gets called "cage aggression" but is simply the animal learning that an open cage has begun to equal getting food and acting on that.