cleaned up apidoc

added some comments
removed configuration.[ch], as it does not make sense like it is

src/charon/sa/ike_sa.c

@@ -436,15 +436,14 @@ static status_t send_dpd(private_ike_sa_t *this)
 static void send_keepalive(private_ike_sa_t *this)
 {
 	send_keepalive_job_t *job;
-	time_t last_out, now, diff, interval;
+	time_t last_out, now, diff;
 	
 	last_out = get_use_time(this, FALSE);
 	now = time(NULL);
 	
 	diff = now - last_out;
-	interval = charon->configuration->get_keepalive_interval(charon->configuration);
 	
-	if (diff >= interval)
+	if (diff >= KEEPALIVE_INTERVAL)
 	{
 		packet_t *packet;
 		chunk_t data;
@@ -462,7 +461,7 @@ static void send_keepalive(private_ike_sa_t *this)
 	}
 	job = send_keepalive_job_create(this->ike_sa_id);
 	charon->event_queue->add_relative(charon->event_queue, (job_t*)job,
-									  (interval - diff) * 1000);
+									  (KEEPALIVE_INTERVAL - diff) * 1000);
 }
 
 /**
@@ -526,9 +525,8 @@ static void set_state(private_ike_sa_t *this, ike_sa_state_t state)
 		{
 			/* delete may fail if a packet gets lost, so set a timeout */
 			job_t *job = (job_t*)delete_ike_sa_job_create(this->ike_sa_id, TRUE);
-			charon->event_queue->add_relative(charon->event_queue, job,
-						  charon->configuration->get_half_open_ike_sa_timeout(
-					  									charon->configuration));
+			charon->event_queue->add_relative(charon->event_queue, job, 
+											  HALF_OPEN_IKE_SA_TIMEOUT);
 			break;
 		}
 		default:
@@ -747,10 +745,9 @@ static status_t process_message(private_ike_sa_t *this, message_t *message)
 			/* add a timeout if peer does not establish it completely */
 			job = (job_t*)delete_ike_sa_job_create(this->ike_sa_id, FALSE);
 			charon->event_queue->add_relative(charon->event_queue, job,
-						  charon->configuration->get_half_open_ike_sa_timeout(
-					  									charon->configuration));
+											  HALF_OPEN_IKE_SA_TIMEOUT);
 		}
-	
+		
 		/* check if message is trustworthy, and update host information */
 		if (this->state == IKE_CREATED ||
 			message->get_exchange_type(message) != IKE_SA_INIT)

src/charon/sa/ike_sa.h

@@ -34,7 +34,6 @@ typedef struct ike_sa_t ike_sa_t;
 #include <sa/ike_sa_id.h>
 #include <sa/child_sa.h>
 #include <sa/tasks/task.h>
-#include <config/configuration.h>
 #include <utils/randomizer.h>
 #include <crypto/prfs/prf.h>
 #include <crypto/crypters/crypter.h>
@@ -42,6 +41,35 @@ typedef struct ike_sa_t ike_sa_t;
 #include <config/peer_cfg.h>
 #include <config/ike_cfg.h>
 
+/**
+ * Timeout in milliseconds after that a half open IKE_SA gets deleted.
+ *
+ * @ingroup sa
+ */
+#define HALF_OPEN_IKE_SA_TIMEOUT 30000
+
+/**
+ * Interval to send keepalives when NATed, in seconds.
+ *
+ * @ingroup sa
+ */
+#define KEEPALIVE_INTERVAL 20
+
+/**
+ * After which time rekeying should be retried if it failed, in seconds.
+ *
+ * @ingroup sa
+ */
+#define RETRY_INTERVAL 30
+
+/**
+ * Jitter to subtract from RETRY_INTERVAL to randomize rekey retry.
+ *
+ * @ingroup sa
+ */
+#define RETRY_JITTER 20
+
+
 /**
  * @brief State of an IKE_SA.
  *

src/charon/sa/task_manager.c

@@ -22,6 +22,8 @@
 
 #include "task_manager.h"
 
+#include <math.h>
+
 #include <daemon.h>
 #include <sa/tasks/ike_init.h>
 #include <sa/tasks/ike_natd.h>
@@ -210,9 +212,12 @@ static status_t retransmit(private_task_manager_t *this, u_int32_t message_id)
 		u_int32_t timeout;
 		job_t *job;
 
-		timeout = charon->configuration->get_retransmit_timeout(
-						charon->configuration, this->initiating.retransmitted);
-		if (timeout == 0)
+		if (this->initiating.retransmitted <= RETRANSMIT_TRIES)
+		{
+			timeout = (u_int32_t)(RETRANSMIT_TIMEOUT *
+						pow(RETRANSMIT_BASE, this->initiating.retransmitted));
+		}
+		else
 		{
 			DBG1(DBG_IKE, "giving up after %d retransmits",
 				 this->initiating.retransmitted - 1);

src/charon/sa/task_manager.h

@@ -30,6 +30,28 @@ typedef struct task_manager_t task_manager_t;
 #include <sa/ike_sa.h>
 #include <sa/tasks/task.h>
 
+/**
+ * First retransmit timeout in milliseconds.
+ *
+ * @ingroup sa
+ */
+#define RETRANSMIT_TIMEOUT 4000
+
+/**
+ * Base which is raised to the power of the retransmission try.
+ *
+ * @ingroup sa
+ */
+#define RETRANSMIT_BASE 1.8
+
+/**
+ * Number of retransmits done before giving up.
+ *
+ * @ingroup sa
+ */
+#define RETRANSMIT_TRIES 5
+
+
 /**
  * @brief The task manager, juggles task and handles message exchanges.
  *
@@ -43,6 +65,24 @@ typedef struct task_manager_t task_manager_t;
  * For the initial IKE_SA setup, several tasks are queued: One for the
  * unauthenticated IKE_SA setup, one for authentication, one for CHILD_SA setup
  * and maybe one for virtual IP assignement.
+ * The task manager is also responsible for retransmission. It uses a backoff 
+ * algorithm. The timeout is calculated using
+ * RETRANSMIT_TIMEOUT * (RETRANSMIT_BASE ** try).
+ * When try reaches RETRANSMIT_TRIES, retransmission is given up.
+ *
+ * Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
+ * @verbatim
+                   | relative | absolute
+   ---------------------------------------------------------
+   4s * (1.8 ** 0) =    4s         4s
+   4s * (1.8 ** 1) =    7s        11s
+   4s * (1.8 ** 2) =   13s        24s
+   4s * (1.8 ** 3) =   23s        47s
+   4s * (1.8 ** 4) =   42s        89s
+   4s * (1.8 ** 5) =   76s       165s
+ 
+   @endberbatim
+ * The peer is considered dead after 2min 45s when no reply comes in.
  *
  * @b Constructors:
  *  - task_manager_create()

src/charon/sa/tasks/child_rekey.c

@@ -192,8 +192,8 @@ static status_t process_i(private_child_rekey_t *this, message_t *message)
 			  this->collision->get_type(this->collision) == CHILD_DELETE))
 		{
 			job_t *job;
-			u_int32_t retry = charon->configuration->get_retry_interval(
-								charon->configuration);
+			u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
+			
 			job = (job_t*)rekey_child_sa_job_create(
 								this->child_sa->get_reqid(this->child_sa),
 								this->child_sa->get_protocol(this->child_sa),

src/charon/sa/tasks/ike_rekey.c

@@ -169,8 +169,7 @@ static status_t process_i(private_ike_rekey_t *this, message_t *message)
 			this->collision->get_type(this->collision) == IKE_DELETE))
 		{
 			job_t *job;
-			u_int32_t retry = charon->configuration->get_retry_interval(
-									charon->configuration);
+			u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
 			job = (job_t*)rekey_ike_sa_job_create(
 									this->ike_sa->get_id(this->ike_sa), FALSE);
 			DBG1(DBG_IKE, "IKE_SA rekeying failed, "