lcls: do not LCLS call legs with different codecs

It is theoretically possible to LCLS two legs that use different
codecs. However, this requires transcoding capabilities on the
local MGW. If the local MGW lacks transcoding features such a
local circuit should be avoided. Enabeling LCLS under such
coditions should be optional (VTY)

- Add check to avoid LCLS on different codec/rate
- Add VTY-Option to optionally override the check
  (MGW is able to transcode)

Change-Id: I157549129a40c64364dc126f67195759e5f1d60f
Related: OS#1602

1 files changed, 12 insertions, 0 deletions

diff --git a/src/osmo-bsc/osmo_bsc_lcls.c b/src/osmo-bsc/osmo_bsc_lcls.c
index 4639c4e36..6aeccb3bb 100644
--- a/src/osmo-bsc/osmo_bsc_lcls.c
+++ b/src/osmo-bsc/osmo_bsc_lcls.c
@@ -274,6 +274,18 @@ static bool lcls_enable_possible(struct gsm_subscriber_connection *conn)
 		return false;
 	}
 
+	if (conn->user_plane.full_rate != conn->lcls.other->user_plane.full_rate
+	    && conn->sccp.msc->lcls_codec_mismatch_allow == false) {
+		LOGPFSM(conn->lcls.fi, "Not enabling LS due to codec mismiatch (channel rate)\n");
+		return false;
+	}
+
+	if (conn->user_plane.chan_mode != conn->lcls.other->user_plane.chan_mode
+	    && conn->sccp.msc->lcls_codec_mismatch_allow == false) {
+		LOGPFSM(conn->lcls.fi, "Not enabling LS due to codec mismiatch (channel mode)\n");
+		return false;
+	}
+
 	return true;
 }