Add SDP translator and PJMEDIA implementation.

This creates the following:
* Asterisk's internal representation of an SDP
* An API for translating SDPs from one format to another
* An implementation of a translator for PJMEDIA

Change-Id: Ie2ecd3cbebe76756577be9b133e84d2ee356d46b

2 files changed, 210 insertions, 0 deletions

diff --git a/main/sdp_repr.c b/main/sdp_repr.c
new file mode 100644
index 000000000..6df243b0e
--- /dev/null
+++ b/main/sdp_repr.c
@@ -0,0 +1,111 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2017, Digium, Inc.
+ *
+ * Mark Michelson <mmichelson@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.
+ */
+
+#include "asterisk.h"
+#include "asterisk/sdp_priv.h"
+#include "asterisk/utils.h"
+
+struct ast_sdp *ast_sdp_alloc(void)
+{
+	struct ast_sdp *new_sdp;
+
+	new_sdp = ast_calloc(1, sizeof *new_sdp);
+	return new_sdp;
+}
+
+static void free_o_line(struct ast_sdp *dead)
+{
+	ast_free(dead->o_line.user);
+	ast_free(dead->o_line.family);
+	ast_free(dead->o_line.addr);
+}
+
+static void free_s_line(struct ast_sdp *dead)
+{
+	ast_free(dead->s_line);
+}
+
+static void free_c_line(struct ast_sdp_c_line *c_line)
+{
+	ast_free(c_line->family);
+	ast_free(c_line->addr);
+}
+
+static void free_t_line(struct ast_sdp_t_line *t_line)
+{
+	return;
+}
+
+static void free_a_line(struct ast_sdp_a_line *a_line)
+{
+	ast_free(a_line->name);
+	ast_free(a_line->value);
+}
+
+static void free_a_lines(struct ast_sdp_a_line_vector *a_lines)
+{
+	int i;
+
+	for (i = 0; i < AST_VECTOR_SIZE(a_lines); ++i) {
+		free_a_line(AST_VECTOR_GET_ADDR(a_lines, i));
+	}
+	AST_VECTOR_FREE(a_lines);
+}
+
+static void free_m_line(struct ast_sdp_m_line *m_line)
+{
+	int i;
+
+	ast_free(m_line->type);
+	ast_free(m_line->profile);
+	free_c_line(&m_line->c_line);
+
+	for (i = 0; i < AST_VECTOR_SIZE(&m_line->payloads); ++i) {
+		ast_free(AST_VECTOR_GET(&m_line->payloads, i));
+	}
+	AST_VECTOR_FREE(&m_line->payloads);
+
+	free_a_lines(&m_line->a_lines);
+}
+
+static void free_m_lines(struct ast_sdp *dead)
+{
+	int i;
+
+	for (i = 0; i < AST_VECTOR_SIZE(&dead->m_lines); ++i) {
+		free_m_line(AST_VECTOR_GET_ADDR(&dead->m_lines, i));
+	}
+
+	AST_VECTOR_FREE(&dead->m_lines);
+}
+
+void ast_sdp_free(struct ast_sdp *dead)
+{
+	if (!dead) {
+		return;
+	}
+
+	free_o_line(dead);
+	free_s_line(dead);
+	free_c_line(&dead->c_line);
+	free_t_line(&dead->t_line);
+	free_a_lines(&dead->a_lines);
+	free_m_lines(dead);
+	ast_free(dead);
+}
+
diff --git a/main/sdp_translator.c b/main/sdp_translator.c
new file mode 100644
index 000000000..5426ae954
--- /dev/null
+++ b/main/sdp_translator.c
@@ -0,0 +1,99 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2017, Digium, Inc.
+ *
+ * Mark Michelson <mmichelson@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.
+ */
+
+#include "asterisk.h"
+#include "asterisk/sdp_options.h"
+#include "asterisk/sdp_translator.h"
+#include "asterisk/logger.h"
+#include "asterisk/utils.h"
+#include "asterisk/lock.h"
+
+AST_RWLOCK_DEFINE_STATIC(registered_ops_lock);
+static struct ast_sdp_translator_ops *registered_ops[AST_SDP_REPR_END];
+
+int ast_sdp_register_translator(struct ast_sdp_translator_ops *ops)
+{
+	SCOPED_WRLOCK(lock, &registered_ops_lock);
+
+	if (ops->repr >= AST_SDP_REPR_END) {
+		ast_log(LOG_ERROR, "SDP translator has unrecognized representation\n");
+		return -1;
+	}
+
+	if (registered_ops[ops->repr] != NULL) {
+		ast_log(LOG_ERROR, "SDP_translator with this representation already registered\n");
+		return -1;
+	}
+
+	registered_ops[ops->repr] = ops;
+	ast_log(LOG_NOTICE, "Placed ops %p at slot %d\n", ops, ops->repr);
+	return 0;
+}
+
+void ast_sdp_unregister_translator(struct ast_sdp_translator_ops *ops)
+{
+	SCOPED_WRLOCK(lock, &registered_ops_lock);
+
+	if (ops->repr >= AST_SDP_REPR_END) {
+		return;
+	}
+
+	registered_ops[ops->repr] = NULL;
+}
+
+struct ast_sdp_translator *ast_sdp_translator_new(enum ast_sdp_options_repr repr)
+{
+	struct ast_sdp_translator *translator;
+	SCOPED_RDLOCK(lock, &registered_ops_lock);
+
+	if (registered_ops[repr] == NULL) {
+		ast_log(LOG_NOTICE, "No registered SDP translator with representation %d\n", repr);
+		return NULL;
+	}
+
+	translator = ast_calloc(1, sizeof(*translator));
+	if (!translator) {
+		return NULL;
+	}
+
+	translator->ops = registered_ops[repr];
+
+	translator->translator_priv = translator->ops->translator_new();
+	if (!translator->translator_priv) {
+		ast_free(translator);
+		return NULL;
+	}
+
+	return translator;
+}
+
+void ast_sdp_translator_free(struct ast_sdp_translator *translator)
+{
+	translator->ops->translator_free(translator->translator_priv);
+	ast_free(translator);
+}
+
+struct ast_sdp *ast_sdp_translator_to_sdp(struct ast_sdp_translator *translator, void *native_sdp)
+{
+	return translator->ops->to_sdp(native_sdp, translator->translator_priv);
+}
+
+void *ast_sdp_translator_from_sdp(struct ast_sdp_translator *translator, struct ast_sdp *ast_sdp)
+{
+	return translator->ops->from_sdp(ast_sdp, translator->translator_priv);
+}