fixed some rekey collision issues

added retry with jitter when rekeying fails

src/charon/config/configuration.c

@@ -72,6 +72,16 @@
  */
 #define KEEPALIVE_INTERVAL 20
 
+/**
+ * retry interval in seconds.
+ */
+#define RETRY_INTERVAL 15
+
+/**
+ * jitter to user for retrying
+ */
+#define RETRY_JITTER 5
+
 
 typedef struct private_configuration_t private_configuration_t;
 
@@ -118,6 +128,14 @@ 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.
  */
@@ -138,6 +156,7 @@ configuration_t *configuration_create()
 	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);
 }

src/charon/config/configuration.h

@@ -61,16 +61,27 @@ struct configuration_t {
 	u_int32_t (*get_half_open_ike_sa_timeout) (configuration_t *this);
 
 	/**
-	 * @brief Returns the keepalive interval in ms.
+	 * @brief Returns the keepalive interval in s.
 	 * 
 	 * The keepalive interval defines the idle time after which a
 	 * NAT keepalive packet should be sent.
 	 * 
 	 * @param this				calling object
-	 * @return					interval in seconds
+	 * @return					interval in s
 	 */	
 	u_int32_t (*get_keepalive_interval) (configuration_t *this);
 
+	/**
+	 * @brief Returns the interval to retry a failed action again.
+	 *
+	 * In some situations, the protocol may be in a state where processing
+	 * is not possible and an action must be retried (e.g. rekeying).
+	 * 
+	 * @param this				calling object
+	 * @return					interval in s
+	 */	
+	u_int32_t (*get_retry_interval) (configuration_t *this);
+
 	/**
 	 * @brief Destroys a configuration_t object.
 	 *