Hi!
As part of the OpenBSC project, I've been working on a dissector for the GSM
A-bis OML protocol. One of the problems with this protocol is that it only
specifies a set of common functions which are then extended by each
vendor/implementor.
This starts with the message type. There are some message types that are
according to the GSM TS 12.21, and then there are vendor-specific message
types. The ranges of the vendor-specific message types overlap.
so let's say the spec has defined 0x01, 0x02, 0x03 and vendor A uses 0x05,
0x06, whereas vendor B uses 0x05 and 0x06 for something completely else.
Thus, it is impossible to make one 'value_string' array that encompasses
all the message types and their names.
Luckily, I can have a preference that allows the user to select which vendor
his trace uses.
My idea was to use the proto_handoff() function to check the preference and
then dynamically allocate (and populate) a value_string[] array that contains
the combination of the standard message types as well as the specific message
types for the preferences-selected vendor.
However, this fails since the hinfo.strings value needs toe have a constant
initializer. And as hfinfo is registered in the proto_register() function,
there is probably no way for me to change this from within proto_handoff()
What is the preferred method to solve this kind of problem? I'm sure the
issue of conflicting vendor-specific extensions must have occurred in other
protocols, too.
Any help is appreciated.
[p.s.: Once the dissector is finished, it will of course be submitted!]
--
- Harald Welte <laforge@xxxxxxxxxxxx> http://laforge.gnumonks.org/
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