Add localhost option to node creation (#520)

* Add localhost option to node creation

Signed-off-by: Brian Ezequiel Marchi <brian.marchi65@gmail.com>

* Bring localhost function from rmw

Signed-off-by: Brian Ezequiel Marchi <brian.marchi65@gmail.com>

* Satisfy uncrustify and address pr comments

Signed-off-by: Brian Ezequiel Marchi <brian.marchi65@gmail.com>

rcl/CMakeLists.txt

@@ -45,6 +45,7 @@ set(${PROJECT_NAME}_sources
   src/rcl/init_options.c
   src/rcl/lexer.c
   src/rcl/lexer_lookahead.c
+  src/rcl/localhost.c
   src/rcl/logging_rosout.c
   src/rcl/logging.c
   src/rcl/node.c

rcl/include/rcl/localhost.h

@@ -0,0 +1,42 @@
+// Copyright 2019 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCL__LOCALHOST_H_
+#define RCL__LOCALHOST_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "rcl/types.h"
+#include "rcl/visibility_control.h"
+
+extern const char * const RCL_LOCALHOST_ENV_VAR;
+
+/// Determine if the user wants to communicate using loopback only.
+/**
+ * Checks if localhost should be used for network communication checking ROS_LOCALHOST_ONLY env
+ * variable
+ * \returns true if ROS_LOCALHOST_ONLY is set and is 1, false otherwise.
+ */
+RCL_PUBLIC
+bool
+rcl_localhost_only();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RCL__LOCALHOST_H_

rcl/src/rcl/localhost.c

@@ -0,0 +1,30 @@
+// Copyright 2019 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <rcl/localhost.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "rcutils/get_env.h"
+
+const char * const RCL_LOCALHOST_ENV_VAR = "ROS_LOCALHOST_ONLY";
+
+bool
+rcl_localhost_only()
+{
+  const char * ros_local_host_env_val = NULL;
+  return rcutils_get_env(RCL_LOCALHOST_ENV_VAR, &ros_local_host_env_val) == NULL &&
+         ros_local_host_env_val != NULL && strcmp(ros_local_host_env_val, "1") == 0;
+}

rcl/src/rcl/node.c

@@ -26,6 +26,7 @@ extern "C"
 
 #include "rcl/arguments.h"
 #include "rcl/error_handling.h"
+#include "rcl/localhost.h"
 #include "rcl/logging.h"
 #include "rcl/logging_rosout.h"
 #include "rcl/rcl.h"
@@ -329,7 +330,7 @@ rcl_node_init(
   }
   node->impl->rmw_node_handle = rmw_create_node(
     &(node->context->impl->rmw_context),
-    name, local_namespace_, domain_id, &node_security_options);
+    name, local_namespace_, domain_id, &node_security_options, rcl_localhost_only());
 
   RCL_CHECK_FOR_NULL_WITH_MSG(
     node->impl->rmw_node_handle, rmw_get_error_string().str, goto fail);