ike: Only track actually sent retransmits as outbound packets

Retransmission jobs for old requests for which we already received a
response previously left the impression that messages were sent more
recently than was actually the case.

task_manager_t always defined INVALID_STATE as possible return value if
no retransmit was sent, this just was never actually returned.

I guess we could further differentiate between actual invalid states
(e.g. if we already received the response) and when we don't send a
retransmit for other reasons e.g. because the IKE_SA became stale.

src/libcharon/sa/ike_sa.c

@@ -2426,9 +2426,16 @@ METHOD(ike_sa_t, retransmit, status_t,
 	{
 		return INVALID_STATE;
 	}
-	this->stats[STAT_OUTBOUND] = time_monotonic(NULL);
+	switch (this->task_manager->retransmit(this->task_manager, message_id))
-	if (this->task_manager->retransmit(this->task_manager, message_id) != SUCCESS)
 	{
+		case SUCCESS:
+			this->stats[STAT_OUTBOUND] = time_monotonic(NULL);
+			return SUCCESS;
+		case INVALID_STATE:
+			return INVALID_STATE;
+		default:
+			break;
+	}
 	/* send a proper signal to brief interested bus listeners */
 	switch (this->state)
 	{
@@ -2499,8 +2506,6 @@ METHOD(ike_sa_t, retransmit, status_t,
 		charon->bus->ike_updown(charon->bus, &this->public, FALSE);
 	}
 	return DESTROY_ME;
-	}
-	return SUCCESS;
 }
 
 METHOD(ike_sa_t, set_auth_lifetime, status_t,

src/libcharon/sa/ike_sa.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2019 Tobias Brunner
+ * Copyright (C) 2006-2020 Tobias Brunner
  * Copyright (C) 2006 Daniel Roethlisberger
  * Copyright (C) 2005-2009 Martin Willi
  * Copyright (C) 2005 Jan Hutter
@@ -872,10 +872,11 @@ struct ike_sa_t {
 	 *
 	 * @param message_id	ID of the request to retransmit
 	 * @return
-	 *						- SUCCESS
+	 *						- SUCCESS if retransmit was sent
-	 *						- NOT_FOUND if request doesn't have to be retransmitted
+	 *						- INVALID_STATE if no retransmit required
+	 *						- DESTROY_ME if this IKE_SA MUST be deleted
 	 */
-	status_t (*retransmit) (ike_sa_t *this, uint32_t message_id);
+	status_t (*retransmit)(ike_sa_t *this, uint32_t message_id);
 
 	/**
 	 * Sends a DPD request to the peer.

src/libcharon/sa/ikev1/task_manager_v1.c

@@ -404,7 +404,7 @@ static status_t retransmit_packet(private_task_manager_t *this, uint32_t seqnr,
 METHOD(task_manager_t, retransmit, status_t,
 	private_task_manager_t *this, uint32_t seqnr)
 {
-	status_t status = SUCCESS;
+	status_t status = INVALID_STATE;
 
 	if (seqnr == this->initiating.seqnr &&
 		array_count(this->initiating.packets))

src/libcharon/sa/ikev2/task_manager_v2.c

@@ -409,7 +409,7 @@ METHOD(task_manager_t, retransmit, status_t,
 						 "deferred");
 					this->ike_sa->set_condition(this->ike_sa, COND_STALE, TRUE);
 					this->initiating.deferred = TRUE;
-					return SUCCESS;
+					return INVALID_STATE;
 				}
 				else if (mobike->is_probing(mobike))
 				{
@@ -443,7 +443,7 @@ METHOD(task_manager_t, retransmit, status_t,
 					 "deferred");
 				this->ike_sa->set_condition(this->ike_sa, COND_STALE, TRUE);
 				this->initiating.deferred = TRUE;
-				return SUCCESS;
+				return INVALID_STATE;
 			}
 		}
 
@@ -451,8 +451,9 @@ METHOD(task_manager_t, retransmit, status_t,
 		job = (job_t*)retransmit_job_create(this->initiating.mid,
 											this->ike_sa->get_id(this->ike_sa));
 		lib->scheduler->schedule_job_ms(lib->scheduler, job, timeout);
-	}
 		return SUCCESS;
+	}
+	return INVALID_STATE;
 }
 
 METHOD(task_manager_t, initiate, status_t,