1 files changed, 120 insertions, 0 deletions
diff --git a/plugin/examples/simple.c b/plugin/examples/simple.c
new file mode 100644
index 0000000..aa823b7
--- /dev/null
+++ b/plugin/examples/simple.c
@@ -0,0 +1,120 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single TCP/UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/*
+ * This file implements a simple OpenVPN plugin module which
+ * will examine the username/password provided by a client,
+ * and make an accept/deny determination.  Will run
+ * on Windows or *nix.
+ *
+ * See the README file for build instructions.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "openvpn-plugin.h"
+
+/*
+ * Our context, where we keep our state.
+ */
+struct plugin_context {
+  const char *username;
+  const char *password;
+};
+
+/*
+ * Given an environmental variable name, search
+ * the envp array for its value, returning it
+ * if found or NULL otherwise.
+ */
+static const char *
+get_env (const char *name, const char *envp[])
+{
+  if (envp)
+    {
+      int i;
+      const int namelen = strlen (name);
+      for (i = 0; envp[i]; ++i)
+	{
+	  if (!strncmp (envp[i], name, namelen))
+	    {
+	      const char *cp = envp[i] + namelen;
+	      if (*cp == '=')
+		return cp + 1;
+	    }
+	}
+    }
+  return NULL;
+}
+
+OPENVPN_EXPORT openvpn_plugin_handle_t
+openvpn_plugin_open_v1 (unsigned int *type_mask, const char *argv[], const char *envp[])
+{
+  struct plugin_context *context;
+
+  /*
+   * Allocate our context
+   */
+  context = (struct plugin_context *) calloc (1, sizeof (struct plugin_context));
+
+  /*
+   * Set the username/password we will require.
+   */
+  context->username = "foo";
+  context->password = "bar";
+
+  /*
+   * We are only interested in intercepting the
+   * --auth-user-pass-verify callback.
+   */
+  *type_mask = OPENVPN_PLUGIN_MASK (OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY);
+
+  return (openvpn_plugin_handle_t) context;
+}
+
+OPENVPN_EXPORT int
+openvpn_plugin_func_v1 (openvpn_plugin_handle_t handle, const int type, const char *argv[], const char *envp[])
+{
+  struct plugin_context *context = (struct plugin_context *) handle;
+
+  /* get username/password from envp string array */
+  const char *username = get_env ("username", envp);
+  const char *password = get_env ("password", envp);
+
+  /* check entered username/password against what we require */
+  if (username && !strcmp (username, context->username)
+      && password && !strcmp (password, context->password))
+    return OPENVPN_PLUGIN_FUNC_SUCCESS;
+  else
+    return OPENVPN_PLUGIN_FUNC_ERROR;
+}
+
+OPENVPN_EXPORT void
+openvpn_plugin_close_v1 (openvpn_plugin_handle_t handle)
+{
+  struct plugin_context *context = (struct plugin_context *) handle;
+  free (context);
+}