1 files changed, 73 insertions, 0 deletions
diff --git a/contrib/auth_delay/auth_delay.c b/contrib/auth_delay/auth_delay.c
new file mode 100644
index 0000000..11c2f05
--- /dev/null
+++ b/contrib/auth_delay/auth_delay.c
@@ -0,0 +1,73 @@
+/* -------------------------------------------------------------------------
+ *
+ * auth_delay.c
+ *
+ * Copyright (c) 2010-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		contrib/auth_delay/auth_delay.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <limits.h>
+
+#include "libpq/auth.h"
+#include "port.h"
+#include "utils/guc.h"
+#include "utils/timestamp.h"
+
+PG_MODULE_MAGIC;
+
+void		_PG_init(void);
+
+/* GUC Variables */
+static int	auth_delay_milliseconds;
+
+/* Original Hook */
+static ClientAuthentication_hook_type original_client_auth_hook = NULL;
+
+/*
+ * Check authentication
+ */
+static void
+auth_delay_checks(Port *port, int status)
+{
+	/*
+	 * Any other plugins which use ClientAuthentication_hook.
+	 */
+	if (original_client_auth_hook)
+		original_client_auth_hook(port, status);
+
+	/*
+	 * Inject a short delay if authentication failed.
+	 */
+	if (status != STATUS_OK)
+	{
+		pg_usleep(1000L * auth_delay_milliseconds);
+	}
+}
+
+/*
+ * Module Load Callback
+ */
+void
+_PG_init(void)
+{
+	/* Define custom GUC variables */
+	DefineCustomIntVariable("auth_delay.milliseconds",
+							"Milliseconds to delay before reporting authentication failure",
+							NULL,
+							&auth_delay_milliseconds,
+							0,
+							0, INT_MAX / 1000,
+							PGC_SIGHUP,
+							GUC_UNIT_MS,
+							NULL,
+							NULL,
+							NULL);
+	/* Install Hooks */
+	original_client_auth_hook = ClientAuthentication_hook;
+	ClientAuthentication_hook = auth_delay_checks;
+}