1 files changed, 162 insertions, 0 deletions
diff --git a/src/charon/config/configuration.c b/src/charon/config/configuration.c
new file mode 100755
index 000000000..488ba9a5e
--- /dev/null
+++ b/src/charon/config/configuration.c
@@ -0,0 +1,162 @@
+/**
+ * @file configuration.c
+ * 
+ * @brief Implementation of configuration_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2006 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include <stdlib.h>
+#include <math.h>
+
+#include "configuration.h"
+
+#include <library.h>
+
+/**
+ * Timeout in milliseconds after that a half open IKE_SA gets deleted.
+ */
+#define HALF_OPEN_IKE_SA_TIMEOUT 30000
+
+/**
+ * Retransmission uses a backoff algorithm. The timeout is calculated using
+ * TIMEOUT * (BASE ** try).
+ * When try reaches TRIES, retransmission is given up.
+ *
+ * Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
+ *
+ *                        | relative | absolute
+ * ---------------------------------------------------------
+ * 4s * (1.8 ** (0  % 5)) =    4s         4s
+ * 4s * (1.8 ** (1  % 5)) =    7s        11s
+ * 4s * (1.8 ** (2  % 5)) =   13s        24s
+ * 4s * (1.8 ** (3  % 5)) =   23s        47s
+ * 4s * (1.8 ** (4  % 5)) =   42s        89s
+ * 4s * (1.8 ** (5  % 5)) =   76s       165s
+ *
+ * The peer is considered dead after 2min 45s when no reply comes in.
+ */
+
+/**
+ * First retransmit timeout in milliseconds.
+ * Timeout value is increasing in each retransmit round.
+ */
+#define RETRANSMIT_TIMEOUT 4000
+
+/**
+ * Base which is raised to the power of the retransmission count.
+ */
+#define RETRANSMIT_BASE 1.8
+
+/**
+ * Number of retransmits done in a retransmit sequence
+ */
+#define RETRANSMIT_TRIES 5
+
+/**
+ * Keepalive interval in seconds.
+ */
+#define KEEPALIVE_INTERVAL 20
+
+/**
+ * retry interval in seconds.
+ */
+#define RETRY_INTERVAL 30
+
+/**
+ * jitter to user for retrying
+ */
+#define RETRY_JITTER 20
+
+
+typedef struct private_configuration_t private_configuration_t;
+
+/**
+ * Private data of an configuration_t object.
+ */
+struct private_configuration_t {
+
+	/**
+	 * Public part of configuration_t object.
+	 */
+	configuration_t public;
+
+};
+
+/**
+ * Implementation of configuration_t.get_retransmit_timeout.
+ */
+static u_int32_t get_retransmit_timeout (private_configuration_t *this,
+										 u_int32_t retransmit_count)
+{
+	if (retransmit_count > RETRANSMIT_TRIES)
+	{
+		/* give up */
+		return 0;
+	}
+	return (u_int32_t)
+				(RETRANSMIT_TIMEOUT * pow(RETRANSMIT_BASE, retransmit_count));
+}
+
+/**
+ * Implementation of configuration_t.get_half_open_ike_sa_timeout.
+ */
+static u_int32_t get_half_open_ike_sa_timeout (private_configuration_t *this)
+{
+	return HALF_OPEN_IKE_SA_TIMEOUT;
+}
+
+/**
+ * Implementation of configuration_t.get_keepalive_interval.
+ */
+static u_int32_t get_keepalive_interval (private_configuration_t *this)
+{
+	return KEEPALIVE_INTERVAL;
+}
+
+/**
+ * Implementation of configuration_t.get_retry_interval.
+ */
+static u_int32_t get_retry_interval (private_configuration_t *this)
+{
+	return RETRY_INTERVAL - (random() % RETRY_JITTER);
+}
+
+/**
+ * Implementation of configuration_t.destroy.
+ */
+static void destroy(private_configuration_t *this)
+{
+	free(this);
+}
+
+/*
+ * Described in header-file
+ */
+configuration_t *configuration_create()
+{
+	private_configuration_t *this = malloc_thing(private_configuration_t);
+	
+	/* public functions */
+	this->public.destroy = (void(*)(configuration_t*))destroy;
+	this->public.get_retransmit_timeout = (u_int32_t (*) (configuration_t*,u_int32_t))get_retransmit_timeout;
+	this->public.get_half_open_ike_sa_timeout = (u_int32_t (*) (configuration_t*)) get_half_open_ike_sa_timeout;
+	this->public.get_keepalive_interval = (u_int32_t (*) (configuration_t*)) get_keepalive_interval;
+	this->public.get_retry_interval = (u_int32_t (*) (configuration_t*)) get_retry_interval;
+	
+	return (&this->public);
+}