Hi,
we have a problem with a device trying to send T.38 fax. During the T.38 ReInvite Kamailio
fails to parse the SDP (via rtpengine_manage), and subsequently rtpengine is failing to do
it's job.
The problem seems to be that Kamailio is trying to find a media address, since there is no
session-wide c= line present it goes to the media c= lines, but since the first media
stream which was an audio stream is being removed (port 0) and can therefore omit all
attributes (as per RFC 3264 8.2, or am i understanding this wrong?), the Kamailio SDP
parser is failing, even if there is another c= line in the T.38 media stream.
Here is the offending SDP from the ReInvite (IP changed):
v=0
o=xmserver 1726638425 1726638427 IN IP4 169.254.1.1
s=xmserver
t=0 0
m=audio 0 RTP/AVP 8
m=image 56002 udptl t38
c=IN IP4 169.254.1.1
a=sendrecv
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxFillBitRemoval:0
a=T38FaxTranscodingMMR:0
a=T38FaxTranscodingJBIG:0
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:200
a=T38FaxMaxDatagram:72
a=T38FaxUdpEC:t38UDPRedundancy
And here is the corresponding log entry:
<core> [core/parser/sdp/sdp.c:523]: parse_sdp_session(): can't find media IP in
the message
Can anyone confirm my findings? Is it possible to adjust the SDP parser for these kind of
scenarios?
Mit kommunikativen Grüßen I Best regards
Thomas