24 Jan
2023
24 Jan
'23
11:05 a.m.
Hi All,
Hope you are all well?
I am hoping you can help with a bit of syntax I am struggling to get working in the
intended way. (We are using Kamailio 5.5.3 and using Kemi/python.)
The scenario is in AWS where we have separate Kamailio and RTPengine instances, with a
cluster of FreeSWITCH EC2's on private addresses only.
In the current setup, all RTP routes via the NAT gateway and back to the private IP of the
selected FreeSWITCH (and vice versa). This works in the current config, but I would want
this traffic not going via the NAT gateway and use the private address and route
internally on the VPC. (These EC'2 have only 1 network interface and that cannot be
changed for this work.)
So anything between FreeSWITCH and Kamailio/RTPengine uses the private IP's for media,
the rest use public IP's.
It is good to note that the RTPengine's are the same in each set (3 total
RTPengine's), just using the public/private IP's based on set ID.
My first aim is to use KSR.permissions.allow_source_address() to check if the source
address is from the FreeSWITCH cluster and set the rtpengine setID based on this. I have
used this method for different parts of the config and it works.
I am failing at this first step it seems, as no matter what I use in the function (below)
it defaults and uses the public IP's in SDP. (No matter if I use the same setID in
each set)
kamailio.cfg snippet:
# ----- rtpengine params -----
modparam("rtpengine", "setid_avp", "$avp()")
# Public IP's ID 1:
modparam("rtpengine", "rtpengine_sock", "1 == udp:5.5.5.5:2223
udp:6.6.6.6:2223 udp:7.7.7.7:2223")
# Internal IP's ID 2:
modparam("rtpengine", "rtpengine_sock", "2 == udp:10.0.0.1:2223
udp:10.0.0.2:2223 udp:10.0.0.3:2223")
Kemi file snippet:
# RTPengine Options for different SetID
def ksr_route_rtpengine(self, msg):
if KSR.textops.has_body_type("application/sdp") > 0 :
# Source address is private subnet - use RTPengine set 2 (private IP's)
if KSR.permissions.allow_source_address(400) == 1:
KSR.rtpengine.set_rtpengine_set(2)
KSR.rtpengine.rtpengine_manage(
"RTP/AVP replace-session-connection replace-origin port-latching
ICE=remove")
else:
# Source address is NOT private - use RTPengine set 1 (public)
KSR.rtpengine.set_rtpengine_set(1)
KSR.rtpengine.rtpengine_manage(
"RTP/AVP replace-session-connection replace-origin port-latching
ICE=remove")
KSR.xlog.xlog("L_INFO", "RTPengine handling Block")
return 1
Group 400 is the private subnet of the FreeSWITCH clusters we have behind on private
addresses and the list contains the subnet of private IP's.
Using the above, the Kamailio starts fine and understands/loads each set of
RTPengine's and calls work with audio. but regardless of the set number used (even
only using set 2 in both) it defaults to public IP's in the SDP. (This is the only
place in the config where this function is defined)
My SDP from FreeSWITCH egress to Kamailio/RTPengine has private IP's in the SDP.
The only thing I do not fully understand is the setid_avp - specifically $avp() block and
if this needs to stay empty, or be duplicated with the set ID in each one.
Any help would be greatly appreciated in understanding where I am going wrong here.
Thanks,
John.