chan_rtp.c: Simplify options to UnicastRTP channel creation.

Change the awkward and not as flexible UnicastRTP options format
From:
Dial(UnicastRTP/127.0.0.1[/[<engine>][/[<codec>]]])
To:
Dial(UnicastRTP/127.0.0.1[/[<options>]])

Where <options> can be standard Asterisk flag options:
c(<codec>) - Specify which codec/format to use such as 'ulaw'.
e(<engine>) - Specify which RTP engine to use such as 'asterisk'.

More option flags can be easily added later such as the codec's RTP
payload type to use when the codec does not have a static payload type
defined.

Change-Id: I0c297aaf09e2ee515536cb7437bb8042ff8ff3c9

1 files changed, 43 insertions, 10 deletions

diff --git a/channels/chan_rtp.c b/channels/chan_rtp.c
index 093602823..0fe66bd20 100644
--- a/channels/chan_rtp.c
+++ b/channels/chan_rtp.c
@@ -176,7 +176,7 @@ static struct ast_channel *multicast_rtp_request(const char *type, struct ast_fo
 		fmt = ast_format_cap_get_format(cap, 0);
 	}
 	if (!fmt) {
-		ast_log(LOG_ERROR, "No format available for sending RTP to '%s'\n",
+		ast_log(LOG_ERROR, "No codec available for sending RTP to '%s'\n",
 			args.destination);
 		goto failure;
 	}
@@ -230,6 +230,25 @@ failure:
 	return NULL;
 }
 
+enum {
+	OPT_RTP_CODEC =  (1 << 0),
+	OPT_RTP_ENGINE = (1 << 1),
+};
+
+enum {
+	OPT_ARG_RTP_CODEC,
+	OPT_ARG_RTP_ENGINE,
+	/* note: this entry _MUST_ be the last one in the enum */
+	OPT_ARG_ARRAY_SIZE
+};
+
+AST_APP_OPTIONS(unicast_rtp_options, BEGIN_OPTIONS
+	/*! Set the codec to be used for unicast RTP */
+	AST_APP_OPTION_ARG('c', OPT_RTP_CODEC, OPT_ARG_RTP_CODEC),
+	/*! Set the RTP engine to use for unicast RTP */
+	AST_APP_OPTION_ARG('e', OPT_RTP_ENGINE, OPT_ARG_RTP_ENGINE),
+END_OPTIONS );
+
 /*! \brief Function called when we should prepare to call the unicast destination */
 static struct ast_channel *unicast_rtp_request(const char *type, struct ast_format_cap *cap, const struct ast_assigned_ids *assignedids, const struct ast_channel *requestor, const char *data, int *cause)
 {
@@ -240,11 +259,13 @@ static struct ast_channel *unicast_rtp_request(const char *type, struct ast_form
 	struct ast_channel *chan;
 	struct ast_format_cap *caps = NULL;
 	struct ast_format *fmt = NULL;
+	const char *engine_name;
 	AST_DECLARE_APP_ARGS(args,
 		AST_APP_ARG(destination);
-		AST_APP_ARG(engine);
-		AST_APP_ARG(format);
+		AST_APP_ARG(options);
 	);
+	struct ast_flags opts = { 0, };
+	char *opt_args[OPT_ARG_ARRAY_SIZE];
 
 	if (ast_strlen_zero(data)) {
 		ast_log(LOG_ERROR, "Destination is required for the 'UnicastRTP' channel\n");
@@ -262,17 +283,26 @@ static struct ast_channel *unicast_rtp_request(const char *type, struct ast_form
 		goto failure;
 	}
 
-	if (!ast_strlen_zero(args.format)) {
-		fmt = ast_format_cache_get(args.format);
+	if (!ast_strlen_zero(args.options)
+		&& ast_app_parse_options(unicast_rtp_options, &opts, opt_args,
+			ast_strdupa(args.options))) {
+		ast_log(LOG_ERROR, "'UnicastRTP' channel options '%s' parse error\n",
+			args.options);
+		goto failure;
+	}
+
+	if (ast_test_flag(&opts, OPT_RTP_CODEC)
+		&& !ast_strlen_zero(opt_args[OPT_ARG_RTP_CODEC])) {
+		fmt = ast_format_cache_get(opt_args[OPT_ARG_RTP_CODEC]);
 		if (!fmt) {
-			ast_log(LOG_ERROR, "Format '%s' not found for sending RTP to '%s'\n",
-				args.format, args.destination);
+			ast_log(LOG_ERROR, "Codec '%s' not found for sending RTP to '%s'\n",
+				opt_args[OPT_ARG_RTP_CODEC], args.destination);
 			goto failure;
 		}
 	} else {
 		fmt = ast_format_cap_get_format(cap, 0);
 		if (!fmt) {
-			ast_log(LOG_ERROR, "No format available for sending RTP to '%s'\n",
+			ast_log(LOG_ERROR, "No codec available for sending RTP to '%s'\n",
 				args.destination);
 			goto failure;
 		}
@@ -283,12 +313,15 @@ static struct ast_channel *unicast_rtp_request(const char *type, struct ast_form
 		goto failure;
 	}
 
+	engine_name = S_COR(ast_test_flag(&opts, OPT_RTP_ENGINE),
+		opt_args[OPT_ARG_RTP_ENGINE], NULL);
+
 	ast_ouraddrfor(&address, &local_address);
-	instance = ast_rtp_instance_new(args.engine, NULL, &local_address, NULL);
+	instance = ast_rtp_instance_new(engine_name, NULL, &local_address, NULL);
 	if (!instance) {
 		ast_log(LOG_ERROR,
 			"Could not create %s RTP instance for sending media to '%s'\n",
-			S_OR(args.engine, "default"), args.destination);
+			S_OR(engine_name, "default"), args.destination);
 		goto failure;
 	}