### UDP 1500 random pkt size ###
#####################################
- name: "random"
  stream:
    self_start: True
    packet:
      binary: stl/udp_1518B_no_crc.pcap 
    mode:
      type: continuous
      pps: 100
    rx_stats: []

    # random packet size 60-1500 update ip.len/checksum/udp.len
    vm: 
       instructions: 
           -     type         : "flow_var"                   # define random varible 60-1500
                 name         : "var_rand_pkt_size"
                 op           : "random" 
                 init_value   : 0 
                 min_value    : 60   
                 max_value    : 1500                         # range must be smaller than pkt size
                 size         : 2

           -     type         : "trim_pkt_size"             # trim packet size
                 name         : "var_rand_pkt_size"     

           -     type         : "write_flow_var"            # update ip.len
                 name         : "var_rand_pkt_size" 
                 add_value    : -14
                 is_big_endian: true
                 pkt_offset   : 16 

           -     type         : "fix_checksum_ipv4"          # update ip.checksum
                 pkt_offset   : 14    

           -     type          : "write_flow_var"            # update udp.len
                 name          : "var_rand_pkt_size" 
                 add_value     : -34
                 is_big_endian : true
                 pkt_offset    : 38