do CN CRCX first
In order to send the MSC's RTP endpoint IP address+port in the initial
SDP, move the MGCP CRCX up to an earlier point in the sequence of
establishing a voice call.
Update the voice call sequence chart to show the effects.
Though the semantic change is rather simple, the patch is rather huge --
things have to happen in a different order, and async waits have to
happen at different times.
The new codec filter helps to carry codec resolution information across
the newly arranged code paths.
Related: SYS#5066
Change-Id: Ie433db1ba0c46d4b97538a969233c155cefac21c
diff --git a/include/osmocom/msc/msc_a.h b/include/osmocom/msc/msc_a.h
index 18eb76c..3b11155 100644
--- a/include/osmocom/msc/msc_a.h
+++ b/include/osmocom/msc/msc_a.h
@@ -208,6 +208,7 @@
bool msc_a_is_accepted(const struct msc_a *msc_a);
bool msc_a_is_establishing_auth_ciph(const struct msc_a *msc_a);
+int msc_a_ensure_cn_local_rtp(struct msc_a *msc_a, struct gsm_trans *cc_trans);
int msc_a_try_call_assignment(struct gsm_trans *cc_trans);
const char *msc_a_cm_service_type_to_use(enum osmo_cm_service_type cm_service_type);