from trex_stl_lib.api import *

class STLS1(object):

    def create_stream (self):
       
        pkt = Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12)/(18*'x')
                 
        vm = STLScVmRaw( [ 
                                STLVmFlowVar(name="v_port",
                                                min_value=4337,
                                                  max_value=5337,
                                                  size=2, op="inc"),
                                STLVmWrFlowVar(fv_name="v_port",
                                            pkt_offset= "UDP.sport" ),
                                STLVmFixChecksumHw(l3_offset="IP",l4_offset="UDP",l4_type=CTRexVmInsFixHwCs.L4_TYPE_UDP),

                            ]
                        )

        return STLStream(packet = STLPktBuilder(pkt = pkt ,vm = vm ) ,
                                mode = STLTXCont(pps = 8000000) )


    def get_streams (self, direction = 0, **kwargs):
        # create 1 stream 
        return [ self.create_stream() ]


# dynamic load - used for trex console or simulator
def register():
    return STLS1()