Dissect payload data as IP packet in Lua custom dissector

Question

Hi,

I have a packet which has some header fields and some payload. I've successfully written a dissector for the packet. So now I can see my own protocol's and field values in Wireshark. Now, the payload data for my protocol is basically an IP Packet data. I want to parse that data as IP Packet and show as a subtree inside my protocol.

Can somebody tell me how to parse my data with a pre defined IP Packet parser/dissector which wireshark already uses to parse IP Packets.

Thanks

Accepted Answer

Can somebody tell me how to parse my data with a pre defined IP Packet parser/dissector which wireshark already uses to parse IP Packets.

You call the standard IP dissector with the remaining bytes of your payload.

See the l2tp dissector for an example:

call_dissector(ip_handle, next_tvb, pinfo, tree);

See also these similar questions.

http://ask.wireshark.org/questions/2334/calling-another-dissector
http://ask.wireshark.org/questions/11608/use-of-call_dissector

UPDATE

I've written my dissector in LUA. Will this work in LUA? When I'm trying it says -

In Lua it works differently. See the following sample code.

http://www.wireshark.org/docs/wsug_html_chunked/wslua_dissector_example.html

First you create a variable and assign it a dissector reference. Then you call the dissector like this:

variable:call()

In your case, something like this:

local ip_dissector = Dissector.get("ip")
ip_dissector:call(...)

See the Lua docs for more information about dissector calling and also this similar question:

http://ask.wireshark.org/questions/18517/calling-lua-dissectors-from-lua-dissector

Regards
Kurt