How to call a sub-dissector in lua
Hello,
I'm streaming CAN data from a CAN2USB interface into Wireshark over a pipe - this works fine so far. Now I'm writing a dissector for a custom protocol where the "1st layer" is to decode the CanId and the "2nd layer" shall decode the payload.
Since *im new to lua I worked through some examples and I'm already able to dissect the CanId but now I want to call a second own written dissector to dissect the payload but I always getting a error that the 2nd dissector is not found
the lua script looks like this: The problem is when I want to call the 2nd dissector with Dissector.get("LoxonePayload") --:call(buffer(offset, buffer:len() - offset):tvb(), packet_info, tree) I always get the error "bad argument #1 to 'get' (Dissector_get: No such dissector)
What make I wrong? I found an example where it is done like this way
Every hints/help appriciated
BR Martin
-- ###############################################################################
-- ## Layer 2: Dissect Payload
-- ###############################################################################
-- Register a protocol named LoxonePayload and followed with its description.
pL2_LoxonePayload = Proto.new("LoxonePayload", "Loxone Payload Dissector")
local fL2 = pL2_LoxonePayload.fields
-- ###############################################################################
-- The argument buffer is the source of packet contents ,and
-- pinfo and tree are the object to display our info
function pL2_LoxonePayload.dissector(buffer, pinfo, tree)
local subtree = tree:add(pL2_LoxonePayload, buffer())
local offset=0
******** some code **********
end
-- ###############################################################################
-- ## Layer 1: Dissect Loxone Link Protocol (CAN Identifier)
-- ###############################################################################
-- Register a protocol named LoxoneLink and followed with its description.
pL1_LoxoneLink = Proto("LoxoneLink", "Loxone Protocol Dissector")
-- Create some local variable and array ,and
-- these variables will be used in the tree in packet decode
local fL1 = pL1_LoxoneLink.fields
-- ###############################################################################
-- This function is regarded as the main function that
-- the argument buffer is the source of packet contents ,and
-- pinfo and tree are the object to display our info
function pL1_LoxoneLink.dissector(buffer, pinfo, tree)
local subtree = tree:add(pL1_LoxoneLink, buffer())
************** some more code ****************
-- call Layer2 dissector for payload
=================> here I get the error from Dissector.get: "No such dissector"
Dissector.get("LoxonePayload") --:call(buffer(offset, buffer:len() - offset):tvb(), packet_info, tree)
end
-- ###############################################################################
-- ## Attach dissector
-- ###############################################################################
-- this sub dissector lox_CanId_Table is from CAN protocol (ID 125)
local lox_CanId_Table = DissectorTable.get("wtap_encap")
lox_CanId_Table:add(125, pL1_LoxoneLink)
Dissector.get("LoxonePayload")won't succeed untilLoxonePayloadis registered - somewhere.If you replace
Dissector.get("LoxonePayload")withDissector.list()and check the output, isLoxonePayloadlisted?