siren: Add format attribute modules for Siren7 and Siren14.

This change removes hardcoded SDP parsing and generation for
Siren7 and Siren14 from chan_sip and moves it to format attribute
modules so it can also be used by chan_pjsip.

With this the fmtp lines for both are added with the bitrate
information.

ASTERISK-26021

Change-Id: Ibb004eda37a14c0a35ef0613f6237977fc800037

1 files changed, 94 insertions, 0 deletions

diff --git a/res/res_format_attr_siren14.c b/res/res_format_attr_siren14.c
new file mode 100644
index 000000000..dea13aec6
--- /dev/null
+++ b/res/res_format_attr_siren14.c
@@ -0,0 +1,94 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2016, Digium, Inc.
+ *
+ * Joshua Colp <jcolp@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \brief Siren14 format attribute interface
+ *
+ * \author Joshua Colp <jcolp@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/module.h"
+#include "asterisk/format.h"
+
+/* Destroy is a required callback and must exist */
+static void siren14_destroy(struct ast_format *format)
+{
+}
+
+/* Clone is a required callback and must exist */
+static int siren14_clone(const struct ast_format *src, struct ast_format *dst)
+{
+	return 0;
+}
+
+static struct ast_format *siren14_parse_sdp_fmtp(const struct ast_format *format, const char *attributes)
+{
+	unsigned int val;
+
+	if (sscanf(attributes, "bitrate=%30u", &val) == 1) {
+		if (val != 48000) {
+			ast_log(LOG_WARNING, "Got siren14 offer at %u bps, but only 48000 bps supported; ignoring.\n", val);
+			return NULL;
+		}
+	}
+
+	/* We aren't modifying the format and once passed back it won't be touched, so use what we were given */
+	return ao2_bump((struct ast_format *)format);
+}
+
+static void siren14_generate_sdp_fmtp(const struct ast_format *format, unsigned int payload, struct ast_str **str)
+{
+	ast_str_append(str, 0, "a=fmtp:%u bitrate=48000\r\n", payload);
+}
+
+static struct ast_format_interface siren14_interface = {
+	.format_destroy = siren14_destroy,
+	.format_clone = siren14_clone,
+	.format_parse_sdp_fmtp = siren14_parse_sdp_fmtp,
+	.format_generate_sdp_fmtp = siren14_generate_sdp_fmtp,
+};
+
+static int load_module(void)
+{
+	if (ast_format_interface_register("siren14", &siren14_interface)) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Siren14 Format Attribute Module",
+	.support_level = AST_MODULE_SUPPORT_CORE,
+	.load = load_module,
+	.unload = unload_module,
+	.load_pri = AST_MODPRI_CHANNEL_DEPEND,
+);