mem-pool: refcount online lease when reassigning it to another tunnel

When we reassign an online lease for the same peer, we have to refcount it.
Otherwise we would set it offline if one of the tunnels goes down, but it is
actually still in use by a the second tunnel. This can finally lead in
assigning the same virtual IP to different peers.

1 files changed, 28 insertions, 5 deletions

diff --git a/src/libhydra/attributes/mem_pool.c b/src/libhydra/attributes/mem_pool.c
index c82b1d02f..16a5b519c 100644
--- a/src/libhydra/attributes/mem_pool.c
+++ b/src/libhydra/attributes/mem_pool.c
@@ -251,6 +251,8 @@ static int get_existing(private_mem_pool_t *this, identification_t *id,
 		if (current == host2offset(this, requested))
 		{
 			offset = current;
+			/* add an additional "online" entry */
+			entry->online->insert_last(entry->online, (void*)current);
 			break;
 		}
 	}
@@ -377,9 +379,10 @@ METHOD(mem_pool_t, acquire_address, host_t*,
 METHOD(mem_pool_t, release_address, bool,
 	private_mem_pool_t *this, host_t *address, identification_t *id)
 {
-	bool found = FALSE;
+	enumerator_t *enumerator;
+	bool found = FALSE, more = FALSE;
 	entry_t *entry;
-	uintptr_t offset;
+	uintptr_t offset, current;
 
 	if (this->size != 0)
 	{
@@ -388,11 +391,31 @@ METHOD(mem_pool_t, release_address, bool,
 		if (entry)
 		{
 			offset = host2offset(this, address);
-			if (entry->online->remove(entry->online, (void*)offset, NULL) > 0)
+
+			enumerator = entry->online->create_enumerator(entry->online);
+			while (enumerator->enumerate(enumerator, &current))
 			{
-				DBG1(DBG_CFG, "lease %H by '%Y' went offline", address, id);
+				if (current == offset)
+				{
+					if (!found)
+					{	/* remove the first entry only */
+						entry->online->remove_at(entry->online, enumerator);
+						found = TRUE;
+					}
+					else
+					{	/* but check for more entries */
+						more = TRUE;
+						break;
+					}
+				}
+			}
+			enumerator->destroy(enumerator);
+
+			if (found && !more)
+			{
+				/* no tunnels are online anymore for this lease, make offline */
 				entry->offline->insert_last(entry->offline, (void*)offset);
-				found = TRUE;
+				DBG1(DBG_CFG, "lease %H by '%Y' went offline", address, id);
 			}
 		}
 		this->mutex->unlock(this->mutex);