SIP end points can send periodic re-INVITES. Previous to this commit,
the osmo-sip-connector would send a new call SETUP to the MSC for each
re-INVITE.
Add a function to find if we already handle this call based on the nua handle.
Use this function to detect and respond with an ACK to re-INVITES.
Add a function to extract the media mode from the SDP.
In the case the re-INVITE has a=sendonly (HOLD) respond with a=recvonly
In the case that the re-INVITE changes the media connection ip/port,
forward this to the MNCC side with an MNCC_RTP_CONNECT
Change-Id: I4083ed50d0cf1b302b80354fe0c2b73fc6e14fed
This enables call hold implemented by subsequent commits
Prior to this commit, osmo-sip-connector would not send
any media mode attribute in the sdp. After this commit
we will by default always include a=sendrecv.
Given that a media mode attribute of "sendrecv" is default
and implicit it its absense, this does not represent any
functional change.
Change-Id: Ib4212d0174955042e7d80d3744ce632a4942ccb2
The codec negotiation is still a huge todo and the initial version
will be far from perfect. We will use whatever MNCC has decided on
and then see if it is compatible in the end.
Keith Whyte
Holger Hans Peter Freyther