The norks do nothing without permission and direction from the chicoms. NK is how the prc distributes it's nuclear weapons and missile technology to the mohammadens and other rogue enemies with "plausible deniability" and provide enough "compensation" to kim il and his henchmen to keep them pliable..
However, there are problems at the top of the DPRK’s power structure. Moreover, the DPRK is even showing bluster against the PRC (placing artillery and MLRs along the PRC-DPRK border). It seems that the DPRK is off their leash.