From 5fbe450e64c8425a7b1854d64d1a2483a68a1e03 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Sun, 10 Dec 2023 07:02:37 +0100 Subject: [PATCH] mgw: do not fail MGCP on codec mismatch Before this patch, when an CRCX+MDCX wants to set a codec list that has no match with the codecs for the other conn of that same endpoint, osmo-mgw returns an MGCP "FAIL" response. When a client wants to change the codec, it has to do that one RTP port at a time. So osmo-mgw *must* allow to configure an MGCP conn with a codec choice that mismatches the other conn. This is crucial to allow codec negotiation in osmo-msc: if MO has already assigned a specific codec, and later wants to re-assign to the codec that MT has chosen, the codec needs to be changed at osmo-mgw. This patch is the minimal fix required to get re-assignment to a different codec to work (via osmo-msc). There is more work to be done about this bit of code in osmo-mgw, but keep that to a separate patch. In detail, before this patch, we fail both - when a side has no codecs, - or when there is no single match between codecs of the two sides of the endpoint. Remove only the second condition; after this patch, still fail when a side has no codecs -- this allows mgcp_test.c to still pass. Related: OS#6293 Related: osmo-msc I8760feaa8598047369ef8c3ab2673013bac8ac8a Change-Id: I3d1163fe622bdd7dc42a485f796072524ab39db9 --- src/libosmo-mgcp/mgcp_codec.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/libosmo-mgcp/mgcp_codec.c b/src/libosmo-mgcp/mgcp_codec.c index 9d29c4e3c..114ef8cc8 100644 --- a/src/libosmo-mgcp/mgcp_codec.c +++ b/src/libosmo-mgcp/mgcp_codec.c @@ -470,7 +470,18 @@ int mgcp_codec_decide(struct mgcp_conn_rtp *conn_src, struct mgcp_conn_rtp *conn } } - return -EINVAL; + LOGP(DLMGCP, LOGL_ERROR, "no matching codec found\n"); + if (conn_dst->end.codecs_assigned) + conn_dst->end.codec = &conn_dst->end.codecs[0]; + else + return -EINVAL; + + if (conn_src->end.codecs_assigned) + conn_src->end.codec = &conn_src->end.codecs[0]; + else + return -EINVAL; + + return 0; } /* Check if the codec has a specific AMR mode (octet-aligned or bandwith-efficient) set. */