test/lua/protobuf_test_called_by_custom_dissector.lua

   1 do
   2     local protobuf_dissector = Dissector.get("protobuf")
   3
   4     -- Create protobuf dissector based on UDP or TCP.
   5     -- The UDP dissector will take the whole tvb as a message.
   6     -- The TCP dissector will parse tvb as format:
   7     --         [4bytes length][a message][4bytes length][a message]...
   8     -- @param name  The name of the new dissector.
   9     -- @param desc  The description of the new dissector.
  10     -- @param for_udp  Register the new dissector to UDP table.(Enable 'Decode as')
  11     -- @param for_tcp  Register the new dissector to TCP table.(Enable 'Decode as')
  12     -- @param msgtype  Message type. This must be the root message defined in your .proto file.
  13     local function create_protobuf_dissector(name, desc, for_udp, for_tcp, msgtype)
  14         local proto = Proto(name, desc)
  15         local f_length = ProtoField.uint32(name .. ".length", "Length", base.DEC)
  16         proto.fields = { f_length }
  17
  18         proto.dissector = function(tvb, pinfo, tree)
  19             local subtree = tree:add(proto, tvb())
  20             if for_udp and pinfo.port_type == 3 then -- UDP
  21                 if msgtype ~= nil then
  22                     pinfo.private["pb_msg_type"] = "message," .. msgtype
  23                 end
  24                 pcall(Dissector.call, protobuf_dissector, tvb, pinfo, subtree)
  25             elseif for_tcp and pinfo.port_type == 2 then -- TCP
  26                 local offset = 0
  27                 local remaining_len = tvb:len()
  28                 while remaining_len > 0 do
  29                     if remaining_len < 4 then -- head not enough
  30                         pinfo.desegment_offset = offset
  31                         pinfo.desegment_len = DESEGMENT_ONE_MORE_SEGMENT
  32                         return -1
  33                     end
  34
  35                     local data_len = tvb(offset, 4):uint()
  36
  37                     if remaining_len - 4 < data_len then -- data not enough
  38                         pinfo.desegment_offset = offset
  39                         pinfo.desegment_len = data_len - (remaining_len - 4)
  40                         return -1
  41                     end
  42                     subtree:add(f_length, tvb(offset, 4))
  43
  44                     if msgtype ~= nil then
  45                         pinfo.private["pb_msg_type"] = "message," .. msgtype
  46                     end
  47                     pcall(Dissector.call, protobuf_dissector,
  48                            tvb(offset + 4, data_len):tvb(), pinfo, subtree)
  49
  50                     offset = offset + 4 + data_len
  51                     remaining_len = remaining_len - 4 - data_len
  52                 end
  53             end
  54             pinfo.columns.protocol:set(name)
  55         end
  56
  57         if for_udp then DissectorTable.get("udp.port"):add(0, proto) end
  58         if for_tcp then DissectorTable.get("tcp.port"):add(0, proto) end
  59         return proto
  60     end
  61
  62     -- default pure protobuf udp and tcp dissector without message type
  63     create_protobuf_dissector("protobuf_udp", "Protobuf UDP")
  64     create_protobuf_dissector("protobuf_tcp", "Protobuf TCP")
  65     -- add more protobuf dissectors with message types
  66     create_protobuf_dissector("AddrBook", "Tutorial AddressBook",
  67                               true, true, "tutorial.AddressBook")
  68 end