Osmo-CC: Add telephone-event selection to helper

src/libosmocc/helper.c

@@ -56,10 +56,10 @@ const char *osmo_cc_helper_audio_accept(void *priv, struct osmo_cc_helper_audio_
 {
 	char offer_sdp[65536];
 	const char *accept_sdp;
-	osmo_cc_session_media_t *media, *selected_media = NULL;
-	osmo_cc_session_codec_t *codec, *selected_codec = NULL;
+	osmo_cc_session_media_t *media, *selected_media;
+	osmo_cc_session_codec_t *codec, *selected_codec, *telephone_event;
 	int rc;
-	int i, selected_i;
+	int i, selected_codec_i, telephone_event_i;
 
 	if (*session_p) {
 		PDEBUG(DCC, DEBUG_ERROR, "Session already set, please fix!\n");
@@ -83,33 +83,53 @@ const char *osmo_cc_helper_audio_accept(void *priv, struct osmo_cc_helper_audio_
 		return NULL;
 	}
 
-	selected_i = -1;
+	selected_media = NULL;
 	osmo_cc_session_for_each_media((*session_p)->media_list, media) {
 		/* only audio */
 		if (media->description.type != osmo_cc_session_media_type_audio)
 			continue;
+		selected_codec_i = -1;
+		selected_codec = NULL;
+		telephone_event_i = -1;
+		telephone_event = NULL;
 		osmo_cc_session_for_each_codec(media->codec_list, codec) {
-			for (i = 0; codecs[i].payload_name; i++) {
-				if (osmo_cc_session_if_codec(codec, codecs[i].payload_name, codecs[i].payload_rate, codecs[i].payload_channels)) {
-					/* select the first matchting codec or the one we prefer */
-					if (selected_i < 0 || i < selected_i) {
-						selected_codec = codec;
-						selected_media = media;
-						selected_i = i;
+			if (!!strcasecmp(codec->payload_name, "telephone-event")) {
+				for (i = 0; codecs[i].payload_name; i++) {
+					if (osmo_cc_session_if_codec(codec, codecs[i].payload_name, codecs[i].payload_rate, codecs[i].payload_channels)) {
+						/* select the first matchting codec or the one we prefer */
+						if (selected_codec_i < 0 || i < selected_codec_i) {
+							selected_codec = codec;
+							selected_codec_i = i;
+							selected_media = media;
+						}
+						/* if we don't force our preferred codec, use the preferred one from the remote */
+						if (!force_our_codec)
+							break;
 					}
-					/* if we don't force our preferred codec, use the preferred one from the remote */
-					if (!force_our_codec)
-						break;
+				}
+			} else {
+				/* special case: add telephone-event, if supported */
+				for (i = 0; codecs[i].payload_name; i++) {
+					if (!!strcasecmp(codecs[i].payload_name, "telephone-event"))
+						continue;
+					telephone_event = codec;
+					telephone_event_i = i;
+					break;
 				}
 			}
 		}
+		/* codec is selected within this media, we are done */
+		if (selected_codec)
+			break;
 	}
 	if (!selected_codec) {
 		PDEBUG(DCC, DEBUG_ERROR, "No codec found in setup message that we support.\n");
 		osmo_cc_free_session(*session_p);
 		return NULL;
 	}
-	osmo_cc_session_accept_codec(selected_codec, codecs[selected_i].encoder, codecs[selected_i].decoder);
+	osmo_cc_session_accept_codec(selected_codec, codecs[selected_codec_i].encoder, codecs[selected_codec_i].decoder);
+	if (telephone_event)
+		osmo_cc_session_accept_codec(telephone_event, codecs[telephone_event_i].encoder, codecs[telephone_event_i].decoder);
 	osmo_cc_session_accept_media(selected_media, 0, 0, NULL, 1, 1, receiver);
 	osmo_cc_rtp_open(selected_media);
 	osmo_cc_rtp_connect(selected_media);