Wireshark-dev: [Wireshark-dev] How to get calling dissector
From: Uli Heilmeier <[email protected]>
Date: Sun, 28 Jan 2018 22:59:15 +0100
Hi all,

TL,DR:
How does a dissector know which dissector called it?

Long version:
I’m currently implementing a dissector for „Session Multiplex Protocol“ (SMP) [1] requested in bug 14110 [2].
The Tabular Data Stream (TDS; MS SQL Server) protocol depends on SMP when using the MARS feature [3].

SMP runs on top of TCP and is a session layer protocol. SMP however has no identifier to specify the next protocol.
When TDS uses SMP the SMP payload itself is TDS. Resulting in dissector stack: Ethernet/IP/TCP/TDS/SMP/TDS.

I want to call the TDS dissector for the SMP payload data only when it was called by TDS. Otherwise just display the data as hex.
How can I get the information which dissector called my dissector?

Any ideas are welcome. Thanks!

[1]: https://msdn.microsoft.com/en-us/library/cc219643.aspx
[2]: https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=14110
[3]: https://docs.microsoft.com/en-us/sql/relational-databases/native-client/features/using-multiple-active-result-sets-mars

Cheers Uli