pjsip: Add PJSIP_PARSE_URI_FROM dialplan function.

Various SIP headers permit a URI to be prefaced with a `display-name`
production that can include characters (like commas and parentheses)
that are problematic for Asterisk's dialplan parser and, specifically
in the case of this patch, the PJSIP_PARSE_URI function.

This patch introduces a new function - `PJSIP_PARSE_URI_FROM` - that
behaves identically to `PJSIP_PARSE_URI` except that the first
argument is now a variable name and not a literal URI.

Fixes #756

(cherry picked from commit 78d63bc11c)

channels/chan_pjsip.c

@@ -3243,6 +3243,11 @@ static struct ast_custom_function chan_pjsip_parse_uri_function = {
 	.read = pjsip_acf_parse_uri_read,
 };
 
+static struct ast_custom_function chan_pjsip_parse_uri_from_function = {
+	.name = "PJSIP_PARSE_URI_FROM",
+	.read = pjsip_acf_parse_uri_read,
+};
+
 static struct ast_custom_function media_offer_function = {
 	.name = "PJSIP_MEDIA_OFFER",
 	.read = pjsip_acf_media_offer_read,
@@ -3305,6 +3310,11 @@ static int load_module(void)
 		goto end;
 	}
 
+	if (ast_custom_function_register(&chan_pjsip_parse_uri_from_function)) {
+		ast_log(LOG_ERROR, "Unable to register PJSIP_PARSE_URI_FROM dialplan function\n");
+		goto end;
+	}
+
 	if (ast_custom_function_register(&media_offer_function)) {
 		ast_log(LOG_WARNING, "Unable to register PJSIP_MEDIA_OFFER dialplan function\n");
 		goto end;
@@ -3378,6 +3388,7 @@ end:
 	ast_custom_function_unregister(&media_offer_function);
 	ast_custom_function_unregister(&chan_pjsip_dial_contacts_function);
 	ast_custom_function_unregister(&chan_pjsip_parse_uri_function);
+	ast_custom_function_unregister(&chan_pjsip_parse_uri_from_function);
 	ast_custom_function_unregister(&session_refresh_function);
 	ast_unregister_application(app_pjsip_hangup);
 	ast_manager_unregister(app_pjsip_hangup);
@@ -3410,6 +3421,7 @@ static int unload_module(void)
 	ast_custom_function_unregister(&media_offer_function);
 	ast_custom_function_unregister(&chan_pjsip_dial_contacts_function);
 	ast_custom_function_unregister(&chan_pjsip_parse_uri_function);
+	ast_custom_function_unregister(&chan_pjsip_parse_uri_from_function);
 	ast_custom_function_unregister(&session_refresh_function);
 	ast_unregister_application(app_pjsip_hangup);
 	ast_manager_unregister(app_pjsip_hangup);

channels/pjsip/dialplan_functions.c

@@ -724,6 +724,7 @@ static int parse_uri_cb(void *data)
 int pjsip_acf_parse_uri_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t buflen)
 {
 	struct parse_uri_args func_args = { 0, };
+	int reading_uri_from_var;
 
 	AST_DECLARE_APP_ARGS(args,
 		AST_APP_ARG(uri_str);
@@ -732,8 +733,29 @@ int pjsip_acf_parse_uri_read(struct ast_channel *chan, const char *cmd, char *da
 
 	AST_STANDARD_APP_ARGS(args, data);
 
+	reading_uri_from_var = !strcasecmp(cmd, "PJSIP_PARSE_URI_FROM");
+
+	if (reading_uri_from_var) {
+		const char *var;
+
+		if (ast_strlen_zero(args.uri_str)) {
+			ast_log(LOG_WARNING, "The name of a variable containing a URI must be specified when using the '%s' dialplan function\n", cmd);
+			return -1;
+		}
+
+		ast_channel_lock(chan);
+		if ((var = pbx_builtin_getvar_helper(chan, args.uri_str))) {
+			args.uri_str = ast_strdupa(var);
+		}
+		ast_channel_unlock(chan);
+	}
+
 	if (ast_strlen_zero(args.uri_str)) {
-		ast_log(LOG_WARNING, "An URI must be specified when using the '%s' dialplan function\n", cmd);
+		if (reading_uri_from_var) {
+			ast_log(LOG_WARNING, "The variable provided to the '%s' dialplan function must contain a URI\n", cmd);
+		} else {
+			ast_log(LOG_WARNING, "A URI must be specified when using the '%s' dialplan function\n", cmd);
+		}
 		return -1;
 	}
 

channels/pjsip/dialplan_functions_doc.xml

@@ -223,7 +223,7 @@
 			<version>17.0.0</version>
 		</since>
 		<synopsis>
-			Parse an uri and return a type part of the URI.
+			Parse a URI and return a type part of the URI.
 		</synopsis>
 		<syntax>
 			<parameter name="uri" required="true">
@@ -272,7 +272,66 @@
 			</parameter>
 		</syntax>
 		<description>
-			<para>Parse an URI and return a specified part of the URI.</para>
+			<para>Parse a URI and return a specified part of the URI.</para>
+		</description>
+	</function>
+	<function name="PJSIP_PARSE_URI_FROM" language="en_US">
+		<since>
+			<version>18.24.0</version>
+			<version>20.9.0</version>
+			<version>21.4.0</version>
+		</since>
+		<synopsis>
+			Parse the contents of a variable as a URI and return a type part of the URI.
+		</synopsis>
+		<syntax>
+			<parameter name="uri" required="true">
+				<para>Name of a variable that contains a URI to parse</para>
+			</parameter>
+			<parameter name="type" required="true">
+				<para>The <literal>type</literal> parameter specifies which URI part to read</para>
+				<enumlist>
+					<enum name="display">
+						<para>Display name.</para>
+					</enum>
+					<enum name="scheme">
+						<para>URI scheme.</para>
+					</enum>
+					<enum name="user">
+						<para>User part.</para>
+					</enum>
+					<enum name="passwd">
+						<para>Password part.</para>
+					</enum>
+					<enum name="host">
+						<para>Host part.</para>
+					</enum>
+					<enum name="port">
+						<para>Port number, or zero.</para>
+					</enum>
+					<enum name="user_param">
+						<para>User parameter.</para>
+					</enum>
+					<enum name="method_param">
+						<para>Method parameter.</para>
+					</enum>
+					<enum name="transport_param">
+						<para>Transport parameter.</para>
+					</enum>
+					<enum name="ttl_param">
+						<para>TTL param, or -1.</para>
+					</enum>
+					<enum name="lr_param">
+						<para>Loose routing param, or zero.</para>
+					</enum>
+					<enum name="maddr_param">
+						<para>Maddr param.</para>
+					</enum>
+				</enumlist>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Parse the contents of the provided variable as a URI and return a specified part of the URI.</para>
 		</description>
 	</function>