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converting userdata to number


length_octect=tvb_get_guint8(tvb,2)&0x3FF;(last ten bits offset value)

ti = proto_tree_add_text(data_tree, tvb, offset, length_octect, "data");

I used the above function in c for the offset length.How to get the length_octect in lua script

I tried something like this:

local length_octect=(buffer((offset,2) or 0x3FF):unit()


but it is giving error as: Lua Error: C:\Program Files\Wireshark1\myproto.lua:104: No such 'unit' function/method/field for object type 'TvbRange'

asked 20 Apr '15, 23:22

lakshmi's gravatar image

accept rate: 0%

edited 20 Apr '15, 23:31

One Answer:


You've got typo in your function name. Try uint() not unit().

answered 20 Apr '15, 23:44

izopizo's gravatar image

accept rate: 0%

yes, i changed that . Now iam getting the following error:

Expert Info (Warn/Malformed): Trying to fetch an unsigned integer with length 18

(20 Apr '15, 23:51) lakshmi

Expert Info (Warn/Malformed): Trying to fetch an unsigned integer with length 18

This warning I am getting for every length greater than 4.

(21 Apr '15, 01:36) lakshmi

This seems to be expected, pr the Lua reference manual found here: tvbrange:uint()

Get a Big Endian (network order) unsigned integer from a TvbRange. The range must be 1, 2, 3 or 4 octets long. Returns

The unsigned integer value.

(21 Apr '15, 05:03) Pascal Quantin