from trex_stl_lib.api import *


# split the range of IP to cores 
#
class STLS1(object):

    def __init__ (self):
        self.fsize  =64;

    def create_stream (self):
        # Create base packet and pad it to size
        size = self.fsize - 4; # HW will add 4 bytes ethernet 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 = STLScVmRaw( [   STLVmFlowVar ( "ip_src",  min_value="10.0.0.1",
                                            max_value="10.0.0.255", size=4, step=1,op="inc"),
                             STLVmWrFlowVar (fv_name="ip_src", pkt_offset= "IP.src" ), # write ip to packet IP.src
                             STLVmFixIpv4(offset = "IP")                                # fix checksum
                                  ]
                              ,split_by_field = "ip_src"  # split to cores base on the tuple generator 
                              ,cache_size =255 # the cache size
                              );

        pkt = STLPktBuilder(pkt = base_pkt/pad,
                            vm = vm)
        stream = STLStream(packet = pkt,
                         mode = STLTXCont())
        #print(stream.to_code())
        return stream


    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()