Convert Userdata to hex in Wireshark Dissector - lua

Question

I'm coding Wireshark Dissector lua script now.
How to convert userdata to hex string?
I want to get output like this 0102030405060708000a0b0c0d0e0f10
I can convert hex string using tostring.
But it omits long data.
Output Image
How to convert userdata to hex string without omit long data?
proto = Proto("Test", "My Test Protocol")
function proto.dissector(buffer, pinfo, tree)
print(tostring(buffer()))
-- "userdata"
-- print(type(buffer()))
end
tcp_table = DissectorTable.get("tcp.port")
tcp_table:add(1234, proto)
Environment
Wireshark 3.2.1

Answer 1

I'm not very familiar with Wireshark, but from a quick look into the manual I get that buffer is a Tvb
and buffer() is equivalent to buffer:range() which returns a TvbRange
There is a Tvb:__tostring function which claims to
Convert the bytes of a Tvb into a string. This is primarily useful for
debugging purposes since the string will be truncated if it is too
long.
Printing a TvbRange is truncated to 24 bytes.
I'd try to get a ByteArray from your Tvb and obtain the hex string of that ByteArray using
11.8.1.14. bytearray:tohex([lowercase], [separator]) Obtain a Lua string of the bytes in a ByteArray as hex-ascii, with given separator
So your code might look something like
proto = Proto("Test", "My Test Protocol")
function proto.dissector(buffer, pinfo, tree)
print(buffer:bytes():tohex())
-- or print(buffer():bytes():tohex())
-- but I guess if you don't give a range in buffer()
-- it will be pretty much the same as buffer.
end