chan_rtp.c: Cleanup ast_request() parameter parsing.

* Fixed NULL crash potential if parameters are missing.

* Reordered some operations so further diagnostic messages can be
more helpful.

Change-Id: Ibbdc67a2496508cbfbfef0cf19c35177ae2fbd70

diff --git a/channels/chan_rtp.c b/channels/chan_rtp.c
index 04eb0b1..56705b1 100644 (file)
--- a/channels/chan_rtp.c
+++ b/channels/chan_rtp.c
@@ -141,19 +141,32 @@ static struct ast_channel *multicast_rtp_request(const char *type, struct ast_fo
        parse = ast_strdupa(data);
        AST_NONSTANDARD_APP_ARGS(args, parse, '/');
 
-       fmt = ast_format_cap_get_format(cap, 0);
+       if (ast_strlen_zero(args.type)) {
+               ast_log(LOG_ERROR, "Type is required for the 'MulticastRTP' channel\n");
+               goto failure;
+       }
 
-       ast_sockaddr_setnull(&control_address);
+       if (ast_strlen_zero(args.destination)) {
+               ast_log(LOG_ERROR, "Destination is required for the 'MulticastRTP' channel\n");
+               goto failure;
+       }
+       if (!ast_sockaddr_parse(&destination_address, args.destination, PARSE_PORT_REQUIRE)) {
+               ast_log(LOG_ERROR, "Destination address '%s' could not be parsed\n",
+                       args.destination);
+               goto failure;
+       }
 
-       if (!ast_strlen_zero(args.control) &&
-               !ast_sockaddr_parse(&control_address, args.control, PARSE_PORT_REQUIRE)) {
+       ast_sockaddr_setnull(&control_address);
+       if (!ast_strlen_zero(args.control)
+               && !ast_sockaddr_parse(&control_address, args.control, PARSE_PORT_REQUIRE)) {
                ast_log(LOG_ERROR, "Control address '%s' could not be parsed\n", args.control);
                goto failure;
        }
 
-       if (!ast_sockaddr_parse(&destination_address, args.destination,
-                               PARSE_PORT_REQUIRE)) {
-               ast_log(LOG_ERROR, "Destination address '%s' could not be parsed\n", args.destination);
+       fmt = ast_format_cap_get_format(cap, 0);
+       if (!fmt) {
+               ast_log(LOG_ERROR, "No format available for sending RTP to '%s'\n",
+                       args.destination);
                goto failure;
        }
 
@@ -162,12 +175,17 @@ static struct ast_channel *multicast_rtp_request(const char *type, struct ast_fo
                goto failure;
        }
 
-       if (!(instance = ast_rtp_instance_new("multicast", NULL, &control_address, args.type))) {
-               ast_log(LOG_ERROR, "Could not create RTP instance for sending media to '%s'\n", args.destination);
+       instance = ast_rtp_instance_new("multicast", NULL, &control_address, args.type);
+       if (!instance) {
+               ast_log(LOG_ERROR,
+                       "Could not create '%s' multicast RTP instance for sending media to '%s'\n",
+                       args.type, args.destination);
                goto failure;
        }
 
-       if (!(chan = ast_channel_alloc(1, AST_STATE_DOWN, "", "", "", "", "", assignedids, requestor, 0, "MulticastRTP/%p", instance))) {
+       chan = ast_channel_alloc(1, AST_STATE_DOWN, "", "", "", "", "", assignedids,
+               requestor, 0, "MulticastRTP/%p", instance);
+       if (!chan) {
                ast_rtp_instance_destroy(instance);
                goto failure;
        }
@@ -216,40 +234,54 @@ static struct ast_channel *unicast_rtp_request(const char *type, struct ast_form
        );
 
        if (ast_strlen_zero(data)) {
+               ast_log(LOG_ERROR, "Destination is required for the 'UnicastRTP' channel\n");
                goto failure;
        }
        parse = ast_strdupa(data);
        AST_NONSTANDARD_APP_ARGS(args, parse, '/');
 
-       if (!ast_strlen_zero(args.format)) {
-               fmt = ast_format_cache_get(args.format);
-       } else {
-               fmt = ast_format_cap_get_format(cap, 0);
-       }
-
-       if (!fmt) {
-               ast_log(LOG_ERROR, "No format specified for sending RTP to '%s'\n", args.destination);
+       if (ast_strlen_zero(args.destination)) {
+               ast_log(LOG_ERROR, "Destination is required for the 'UnicastRTP' channel\n");
                goto failure;
        }
-
-       if (!ast_sockaddr_parse(&address, args.destination,
-                               PARSE_PORT_REQUIRE)) {
+       if (!ast_sockaddr_parse(&address, args.destination, PARSE_PORT_REQUIRE)) {
                ast_log(LOG_ERROR, "Destination '%s' could not be parsed\n", args.destination);
                goto failure;
        }
 
+       if (!ast_strlen_zero(args.format)) {
+               fmt = ast_format_cache_get(args.format);
+               if (!fmt) {
+                       ast_log(LOG_ERROR, "Format '%s' not found for sending RTP to '%s'\n",
+                               args.format, 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",
+                               args.destination);
+                       goto failure;
+               }
+       }
+
        caps = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
        if (!caps) {
                goto failure;
        }
 
        ast_ouraddrfor(&address, &local_address);
-       if (!(instance = ast_rtp_instance_new(args.engine, NULL, &local_address, NULL))) {
-               ast_log(LOG_ERROR, "Could not create RTP instance for sending media to '%s'\n", args.destination);
+       instance = ast_rtp_instance_new(args.engine, 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);
                goto failure;
        }
 
-       if (!(chan = ast_channel_alloc(1, AST_STATE_DOWN, "", "", "", "", "", assignedids, requestor, 0, "UnicastRTP/%s-%p", args.destination, instance))) {
+       chan = ast_channel_alloc(1, AST_STATE_DOWN, "", "", "", "", "", assignedids,
+               requestor, 0, "UnicastRTP/%s-%p", args.destination, instance);
+       if (!chan) {
                ast_rtp_instance_destroy(instance);
                goto failure;
        }
@@ -268,9 +300,11 @@ static struct ast_channel *unicast_rtp_request(const char *type, struct ast_form
 
        ast_channel_tech_pvt_set(chan, instance);
 
-       pbx_builtin_setvar_helper(chan, "UNICASTRTP_LOCAL_ADDRESS", ast_sockaddr_stringify_addr(&local_address));
+       pbx_builtin_setvar_helper(chan, "UNICASTRTP_LOCAL_ADDRESS",
+               ast_sockaddr_stringify_addr(&local_address));
        ast_rtp_instance_get_local_address(instance, &local_address);
-       pbx_builtin_setvar_helper(chan, "UNICASTRTP_LOCAL_PORT", ast_sockaddr_stringify_port(&local_address));
+       pbx_builtin_setvar_helper(chan, "UNICASTRTP_LOCAL_PORT",
+               ast_sockaddr_stringify_port(&local_address));
 
        ast_channel_unlock(chan);