from trex_stl_lib.api import * # step is not 1. class STLS1(object): def __init__ (self): self.fsize =64; # the size of the packet def create_stream (self): # create a base packet and pad it to size size = self.fsize - 4; # no FCS base_pkt = Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12,sport=1025) pad = max(0, size - len(base_pkt)) * 'x' vm = CTRexScRaw( [ STLVmFlowVar(name="mac_src", min_value=1, max_value=30, size=2, op="dec",step=1), STLVmWrMaskFlowVar(fv_name="mac_src", pkt_offset= 10,pkt_cast_size=1, mask=0x1,shift=-1) # take var mac_src>>1 and write the LSB every two packet there should be a change ] ) return STLStream(packet = STLPktBuilder(pkt = base_pkt/pad,vm = vm), mode = STLTXCont( pps=10 )) def get_streams (self, direction = 0): # create 1 stream return [ self.create_stream() ] # dynamic load - used for trex console or simulator def register(): return STLS1()