wireshark-nmrp.lua

   1 --
   2 -- NMRP dissector for Wireshark
   3 --
   4 -- Copyright (C) 2016 Joseph C. Lehner
   5 --
   6 -- Licensed under the GNU GPL 3.0
   7 --
   8
   9 nmrp_proto = Proto("nmrp", "NMRP")
  10
  11 src_f = ProtoField.string("nmrp.src", "Source")
  12 dst_f = ProtoField.string("nmrp.dst", "Destination")
  13 code_f = ProtoField.uint8("nmrp.code", "Code", base.HEX)
  14 id_f = ProtoField.uint8("nmrp.id", "ID", base.HEX)
  15 reserved_f = ProtoField.uint16("nmrp.reserved", "Reserved", base.HEX)
  16 len_f = ProtoField.uint16("nmrp.len", "Length")
  17 data_f = ProtoField.bytes("nmrp.opt", "Options")
  18 opt_type_f = ProtoField.uint16("nmrp.opt.type", "Option", base.HEX)
  19 opt_len_f = ProtoField.uint16("nmrp.opt.len", "Length")
  20 opt_data_f = ProtoField.bytes("nmrp.opt.data", "Data")
  21
  22 nmrp_proto.fields = {
  23         code_f, reserved_f, len_f, data_f, id_f, opt_type_f, opt_len_f, opt_data_f
  24 }
  25
  26 function nmrp_code(code)
  27         if code == 1 then return { "ADVERTISE", "Advertise" }
  28         elseif code == 2 then return { "CONF_REQ", "Configuration Request" }
  29         elseif code == 3 then return { "CONF_ACK", "Configuration" }
  30         elseif code == 4 then return { "CLOSE_REQ", "Close Request" }
  31         elseif code == 5 then return { "CLOSE_ACK", "Close Acknowledgement" }
  32         elseif code == 6 then return { "KEEP_ALIVE_REQ", "Keep-alive Request" }
  33         elseif code == 7 then return { "KEEP_ALIVE_ACK", "Keep-alive Acknowledgement" }
  34         elseif code == 16 then return { "TFTP_UL_REQ", "Upload Request" }
  35         else return { "#" .. code, "Unknown Opcode " .. code }
  36         end
  37 end
  38
  39 function nmrp_opt(opt)
  40         if opt == 0x01 then return "Magic"
  41         elseif opt == 0x02 then return "IP Configuration"
  42         elseif opt == 0x04 then return "Region"
  43         elseif opt == 0x0101 then return "Update Firmware"
  44         elseif opt == 0x0102 then return "Update String Table"
  45         elseif opt == 0x0181 then return "Filename"
  46         else return "#" .. opt
  47         end
  48 end
  49
  50 function nmrp_dissect_opt(opt, buffer, tree)
  51         if buffer:len() <= 4 then
  52                 return
  53         end
  54
  55         if opt == 0x01 or opt == 0x0181 then
  56                 tree:add(buffer(4), "Value: " .. buffer(4):string())
  57         elseif opt == 0x02 then
  58                 tree:add(buffer(4, 4), "Address: " .. tostring(buffer(4, 4):ipv4()))
  59                 tree:add(buffer(8, 4), "Netmask: " .. tostring(buffer(8, 4):ipv4()))
  60         else
  61                 tree:add(opt_len_f, buffer(2, 2))
  62                 tree:add(opt_data_f, buffer(4, buffer:len() - 4))
  63         end
  64 end
  65
  66
  67 function nmrp_proto.dissector(buffer, pinfo, tree)
  68         pinfo.cols.protocol = "NMRP"
  69
  70         local code = buffer(2, 1)
  71         local len = buffer(4, 2)
  72
  73         pinfo.cols.info = nmrp_code(code:uint())[2]
  74
  75         local subtree = tree:add(nmrp_proto, buffer(0))
  76         subtree:add(code_f, code):append_text(" - " .. nmrp_code(code:uint())[2])
  77         subtree:add(id_f, buffer(3, 1))
  78         subtree:add(len_f, len)
  79         subtree:add(reserved_f, buffer(0, 2))
  80
  81         local databuf = buffer(6, len:uint() - 6)
  82
  83         while databuf:len() > 0 do
  84                 local opt = databuf(0, 2):uint()
  85                 local optlen = databuf(2, 2):uint()
  86
  87                 if databuf:len() < optlen then
  88                         break
  89                 end
  90
  91                 local optitem = subtree:add(opt_type_f, databuf(0, 2)):append_text(" - " .. nmrp_opt(opt))
  92                 nmrp_dissect_opt(opt, databuf(0, optlen), optitem)
  93
  94                 if databuf:len() > optlen then
  95                         databuf = databuf(optlen)
  96                 else
  97                         break
  98                 end
  99         end
 100 end
 101
 102 eth_table = DissectorTable.get("ethertype")
 103 eth_table:add(0x0912, nmrp_proto)