vpp-swan: Add plugin for vpp-swan

Added plugin vpp-swan is a plugin that helps offloading
Strongswan IPsec ESP process from Linux Kernel to VPP.

Type: feature
Signed-off-by: Gabriel Oginski <gabrielx.oginski@intel.com>
Change-Id: Iec77945892453fac1890d3c49d7d86fc6b09c893

extras/strongswan/vpp_sswan/kernel_vpp_plugin.h

@@ -0,0 +1,34 @@
+#ifndef KERNEL_VPP_PLUGIN_H_
+#define KERNEL_VPP_PLUGIN_H_
+/*
+ * Copyright (c) 2022 Intel and/or its affiliates.
+ * 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 <plugins/plugin.h>
+
+typedef struct kernel_vpp_plugin_t kernel_vpp_plugin_t;
+
+/**
+ * vpp kernel interface plugin
+ */
+struct kernel_vpp_plugin_t
+{
+
+  /**
+   * implements plugin interface
+   */
+  plugin_t plugin;
+};
+
+#endif /** KERNEL_VPP_PLUGIN_H_ @}*/