Wireshark-dev: Re: [Wireshark-dev] function of dissector_try_uint()
From: Anders Broman <[email protected]>
Date: Mon, 16 Feb 2015 14:05:11 +0000



From: [email protected] [mailto:[email protected]] On Behalf Of Vishnu Bhatt
Sent: den 16 februari 2015 14:55
To: Developer support list for Wireshark
Subject: [Wireshark-dev] function of dissector_try_uint()




>I have a dissector code (atmii) and I am having problem in understanding the following two lines of code:


>In proto_register_atmii()


>aal_dissector_table = register_dissector_table("atmii.aal2_payload", "AAL payload type", FT_UINT8, BASE_DEC);


Registers a dissector table with the name  atmii.aal2_payload in which it will be possible to register a callback for an UINT8 value. Compare with the UDP table where a dissector can

Register to be called for a message with UDP port number. SIP registers for port 5060 for instance.


and then in dissect_atmii()


if (!dissector_try_port(aal_dissector_table, payload_type, next_tvb, pinfo, tree)) {

proto_tree_add_item(atmii_tree,hf_atmii_aal2_payload, tvb, ATM_HEADER_LENGTH, -1, FALSE);



The atmii.aal2_payload  table will be searched for a match on payload type if a match is found the callback will be executed handing next_tvb to the called function.

If no match is found(no dissector registered for the payload type FALSE will be returned.


>What does these two lines of code do in general as I’ve seen them in other protocols as well?




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