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do
local protobuf_dissector = Dissector.get("protobuf")
-- Create protobuf dissector based on UDP or TCP.
-- The UDP dissector will take the whole tvb as a message.
-- The TCP dissector will parse tvb as format:
-- [4bytes length][a message][4bytes length][a message]...
-- @param name The name of the new dissector.
-- @param desc The description of the new dissector.
-- @param for_udp Register the new dissector to UDP table.(Enable 'Decode as')
-- @param for_tcp Register the new dissector to TCP table.(Enable 'Decode as')
-- @param msgtype Message type. This must be the root message defined in your .proto file.
local function create_protobuf_dissector(name, desc, for_udp, for_tcp, msgtype)
local proto = Proto(name, desc)
local f_length = ProtoField.uint32(name .. ".length", "Length", base.DEC)
proto.fields = { f_length }
proto.dissector = function(tvb, pinfo, tree)
local subtree = tree:add(proto, tvb())
if for_udp and pinfo.port_type == 3 then -- UDP
if msgtype ~= nil then
pinfo.private["pb_msg_type"] = "message," .. msgtype
end
pcall(Dissector.call, protobuf_dissector, tvb, pinfo, subtree)
elseif for_tcp and pinfo.port_type == 2 then -- TCP
local offset = 0
local remaining_len = tvb:len()
while remaining_len > 0 do
if remaining_len < 4 then -- head not enough
pinfo.desegment_offset = offset
pinfo.desegment_len = DESEGMENT_ONE_MORE_SEGMENT
return -1
end
local data_len = tvb(offset, 4):uint()
if remaining_len - 4 < data_len then -- data not enough
pinfo.desegment_offset = offset
pinfo.desegment_len = data_len - (remaining_len - 4)
return -1
end
subtree:add(f_length, tvb(offset, 4))
if msgtype ~= nil then
pinfo.private["pb_msg_type"] = "message," .. msgtype
end
pcall(Dissector.call, protobuf_dissector,
tvb(offset + 4, data_len):tvb(), pinfo, subtree)
offset = offset + 4 + data_len
remaining_len = remaining_len - 4 - data_len
end
end
pinfo.columns.protocol:set(name)
end
if for_udp then DissectorTable.get("udp.port"):add(0, proto) end
if for_tcp then DissectorTable.get("tcp.port"):add(0, proto) end
return proto
end
-- default pure protobuf udp and tcp dissector without message type
create_protobuf_dissector("protobuf_udp", "Protobuf UDP")
create_protobuf_dissector("protobuf_tcp", "Protobuf TCP")
-- add more protobuf dissectors with message types
create_protobuf_dissector("AddrBook", "Tutorial AddressBook",
true, true, "tutorial.AddressBook")
end
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