14 May
2014
14 May
'14
1:51 p.m.
Hello list,
Can anybody suggest the way to remove a line/attribute from SDP that
matches some pattern (regexp), some kind of "grep -v" for SDP ?
I'm trying to remove unnecessary ICE candidates from the SDP body and
only thing I know is the IP address of the candidate I need to remove.
I was trying to use avp_subst() + set_body() or subst_body() but didn't
get valid SDP.
kamailio-3.2.4.
14 May
14 May
2:12 p.m.
Hi Vitaliy,
On 05/14/2014 06:51 AM, Vitaliy Aleksandrov wrote:
Hello list,
Can anybody suggest the way to remove a line/attribute from SDP that
matches some pattern (regexp), some kind of "grep -v" for SDP ?
I'm trying to remove unnecessary ICE candidates from the SDP body and
only thing I know is the IP address of the candidate I need to remove.
I was trying to use avp_subst() + set_body() or subst_body() but didn't
get valid SDP.
You might be able to pull it off using the various subst and other
textops functions:
http://kamailio.org/docs/modules/4.1.x/modules/textops.html
http://kamailio.org/docs/modules/4.1.x/modules/textopsx.html#textopsx.f.rem…
But those may not be sophisticated enough to do the trick, in which case
you might just need to pass this SDP body off to a third-party scripting
language like Perl or Python. There, you can make the modifications you
want, return a new SDP body to Kamailio, remove the old SDP body, and
append your new one.
Cheers,
-- Alex
--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
3:39 p.m.
I can share my solution, using app_python. I'm using this in production
environment during 2 years.
loadmodule "app_python.so"
modparam("app_python", "script_name",
"/opt/kamailio/python/sdp.py")
modparam("app_python", "mod_init_function", "mod_init")
modparam("app_python", "child_init_method", "child_init")
and put in route():
python_exec("ParseSDP", $mb);
Here I shared sdp.py:
http://paste.debian.net/99473/
Note, that it is just for reference only, you need to know what to
remove/replace. That script is not exactly what are you're looking for!
11:05 p.m.
I absolutely forgot about the possibility of embedding scripting
languages to configuration.
Lua did the trick.
Thanks for the right direction and example.
I can share my solution, using app_python. I'm
using this in
production environment during 2 years.
loadmodule "app_python.so"
modparam("app_python", "script_name",
"/opt/kamailio/python/sdp.py")
modparam("app_python", "mod_init_function", "mod_init")
modparam("app_python", "child_init_method", "child_init")
and put in route():
python_exec("ParseSDP", $mb);
Here I shared sdp.py:
http://paste.debian.net/99473/
Note, that it is just for reference only, you need to know what to
remove/replace. That script is not exactly what are you're looking for!
_______________________________________________
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sr-users(a)lists.sip-router.org
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4:31 p.m.
Can anybody suggest the way to remove a line/attribute
from SDP that matches some pattern (regexp), some kind of "grep -v" for SDP ?
Another possibility might be to intentionally mangle an SDP offer so that it's
unrecognizable.
Background: Asterisk is our VM and Media server. We had a case where we were using SRTP
between handsets, but Asterisk would crash if a handset offered SRTP and Asterisk
didn't have the SRTP module loaded. Our temporary workaround was to mangle the SDP
offer so that Asterisk didn't see the offending SRTP offer.
This route replaces any "RTP/SAVP" with "RTP/GARBAGIO". Which Asterisk
doesn't recognize, and therefore didn't invoke the bad behavior. We found this
easier and lighter weight than trying to remove the line entirely, quite suitable for the
temporary hack we needed.
route[INSECUREFWD]
{
if (method=="INVITE") {
subst("/^m=audio(.+)RTP\/SAVP/m=audio\1RTP\/GARBAGIO/");
}
route(FORWARD);
}
-- Jorj
--
Jorj Bauer
Manager of Engineering, Research and Development
Information Systems and Computing, University of Pennsylvania
215.746.3850
XMPP: jorj(a)upenn.edu
3852
days inactive
3852
days old
4 comments
4 participants
participants (4)
-
Alex Balashov -
Jorj Bauer -
Konstantin M. -
Vitaliy Aleksandrov