def METHOD_NAME(self):
    size = self.pptphdr.msgsize - len(self.pptphdr)
    msgtype = self.pptphdr.msgtype
    if msgtype == StartCtrlConnReq:
        self.pptpmsg.protover   = v_uint16(bigend=True)
        self.pptpmsg.res1       = v_uint16(bigend=True)
        self.pptpmsg.framecapa  = v_uint32(bigend=True)
        self.pptpmsg.bearrcapa  = v_uint32(bigend=True)
        self.pptpmsg.maxchan    = v_uint16(bigend=True)
        self.pptpmsg.firmware   = v_uint16(bigend=True)
        self.pptpmsg.hostname   = v_str(size=64)
        self.pptpmsg.vendor   = v_str(size=64)
        return
    if msgtype == StartCtrlConnRep:
        self.pptpmsg.protover   = v_uint16(bigend=True)
        self.pptpmsg.rescode    = v_uint8()
        self.pptpmsg.errcode    = v_uint8()
        self.pptpmsg.framecapa  = v_uint32(bigend=True)
        self.pptpmsg.bearrcapa  = v_uint32(bigend=True)
        self.pptpmsg.maxchan    = v_uint16(bigend=True)
        self.pptpmsg.firmware   = v_uint16(bigend=True)
        self.pptpmsg.hostname   = v_str(size=64)
        self.pptpmsg.vendor   = v_str(size=64)
        return
    if msgtype in (StopCtrlConnReq,StopCtrlConnRep):
        self.pptpmsg.reason     = v_uint8()
        self.pptpmsg.res1       = v_uint8()
        self.pptpmsg.res2       = v_uint16(bigend=True)
    self.pptpmsg.payload = v_bytes(size=size)