Huge thanks to our Platinum Members Endace and LiveAction,
and our Silver Member Veeam, for supporting the Wireshark Foundation and project.

Ethereal-dev: [Ethereal-dev] H.245 requesting help

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: "Ronnie Sahlberg" <ronnie_sahlberg@xxxxxxxxxxxxxx>
Date: Fri, 4 Jul 2003 00:11:42 +1000
Hi list.  Hi telco people.

Some people on this list may be interested in pre-testing debugging of a
H.245 dissector I am working on.


Some of you people have expressed interest earlier and I have privately
mailed an old work copy to you.
(but not the list since 1, it is incomplete 2, it is BIG,  ~30.000 lines)
I dont remember who I sent it to since I had an "issue" with Outlook and
Windows recently.


The dissector is currently reasonably complete and should decode almost all
of H.245
(with the exception of uncommon things like the PER aggregates for
GeneticString, a constrained integer with
an extension marker  etc etc)
It currently does decode all the H.245 packets i have in my captures as far
as i can see properly.
This includes  optional choice/sequence entries and extension entries for
sequence types!


The dissector currently also contain ~2000 lines which are helper routines
to dissect common PER types
such as normally-small-whole-number,  constrained-integer,  sequence/set,
sequence-of/set-of , booleans,
object-identifier,  octet-strings    etc.  These routines would later be
moved into its own source file
asn1-per.c or something similar so they can be used for other PER based
protocols.


The dissector is easy to install, just cpoy it to the source directory, add
it to Makefile.[am|nmake] and recompile.


The dissector is for H.245 ONLY and does NOT include H.225 or H.235  so
ethereal can not determine what is H.245 and what is not.   It is nessecary
to select a packet one knows is H.245 and then specify H.245 in DecodeAs...


H.225 and H.235 could come later   they are both fairly small compared to
H.245.


If anyone is interested in H.245, maybe you can mail me and test the
dissector  and report all undecoded/misdecoded
features you find back to me so I can fix them before considering whether it
should be added to ethereal or not.
I would also really really appreciate capture files that are not decoded
properly with this dissector.
I do not normally encounter these kinds of protocols so my access to
relevant capture files is very limited. Though I feel I should try to
complete this effort since it has already taken too much time   and
hopefully someone else would benefit
from ALIGNED-PER helper subroutines for something.

best regards
    ronnie sahlberg