charon-tkm: Add acquire_ref method to ID manager

The function acquires a reference to the given context reference id for
a specific context kind.

src/charon-tkm/src/tkm/tkm_id_manager.c

@@ -103,6 +103,33 @@ METHOD(tkm_id_manager_t, acquire_id, int,
 	return id;
 }
 
+METHOD(tkm_id_manager_t, acquire_ref, bool,
+	private_tkm_id_manager_t * const this, const tkm_context_kind_t kind,
+	const int ref_id)
+{
+	const int idx = ref_id - 1;
+
+	if (!is_valid_kind(kind))
+	{
+		DBG1(DBG_LIB, "tried to acquire reference for invalid context kind '%d'",
+			 kind);
+		return FALSE;
+	}
+
+	if (ref_id < 1 || (uint64_t)ref_id > this->limits[kind])
+	{
+		DBG1(DBG_LIB, "tried to acquire reference for context id %d out of "
+			 "bounds (max %llu)", ref_id, this->limits[kind]);
+		return FALSE;
+	}
+
+	this->locks[kind]->write_lock(this->locks[kind]);
+	this->ctxids[kind][idx]++;
+	this->locks[kind]->unlock(this->locks[kind]);
+
+	return TRUE;
+}
+
 METHOD(tkm_id_manager_t, release_id, bool,
 	private_tkm_id_manager_t * const this, const tkm_context_kind_t kind,
 	const int id)
@@ -150,6 +177,7 @@ tkm_id_manager_t *tkm_id_manager_create(const tkm_limits_t limits)
 	INIT(this,
 		.public = {
 			.acquire_id = _acquire_id,
+			.acquire_ref = _acquire_ref,
 			.release_id = _release_id,
 			.destroy = _destroy,
 		},

src/charon-tkm/src/tkm/tkm_id_manager.h

@@ -73,6 +73,18 @@ struct tkm_id_manager_t {
 	int (*acquire_id)(tkm_id_manager_t * const this,
 					  const tkm_context_kind_t kind);
 
+	/**
+	 * Acquire reference to given context id for a specific context kind.
+	 *
+	 * @param kind			kind of context id
+	 * @param ref_id		id to acquire a reference for
+	 * @return				TRUE if reference could be acquired,
+	 *						FALSE otherwise
+	 */
+	bool (*acquire_ref)(tkm_id_manager_t * const this,
+						const tkm_context_kind_t kind,
+						const int ref_id);
+
 	/**
 	 * Release a previously acquired context id.
 	 *

src/charon-tkm/tests/id_manager_tests.c

@@ -84,6 +84,71 @@ START_TEST(test_acquire_id_same)
 }
 END_TEST
 
+START_TEST(test_acquire_ref)
+{
+	int i, id = 0;
+	bool acquired = false;
+	tkm_id_manager_t *idmgr = tkm_id_manager_create(limits);
+
+	for (i = 0; i < TKM_CTX_MAX; i++)
+	{
+		id = idmgr->acquire_id(idmgr, i);
+		acquired = idmgr->acquire_ref(idmgr, i, id);
+		fail_unless(acquired, "Error acquiring reference context kind %d", i);
+
+		/* Reset test variable */
+		acquired = false;
+	}
+
+	idmgr->destroy(idmgr);
+}
+END_TEST
+
+START_TEST(test_acquire_ref_invalid_kind)
+{
+	bool acquired;
+	tkm_id_manager_t *idmgr = tkm_id_manager_create(limits);
+
+	acquired = idmgr->acquire_ref(idmgr, TKM_CTX_MAX, 1);
+	fail_if(acquired, "Acquired reference for invalid context kind %d", TKM_CTX_MAX);
+
+	/* Reset test variable */
+	acquired = 0;
+
+	acquired = idmgr->acquire_ref(idmgr, -1, 1);
+	fail_if(acquired, "Acquired reference for invalid context kind %d", -1);
+
+	idmgr->destroy(idmgr);
+}
+END_TEST
+
+START_TEST(test_acquire_ref_invalid_id)
+{
+	int i;
+	bool acquired;
+	tkm_id_manager_t *idmgr = tkm_id_manager_create(limits);
+
+	for (i = 0; i < TKM_CTX_MAX; i++)
+	{
+		acquired = idmgr->acquire_ref(idmgr, i, -1);
+		fail_if(acquired,
+				"Acquired reference for negative id of context kind %d", i);
+
+		/* Reset test variable */
+		acquired = false;
+
+		acquired = idmgr->acquire_ref(idmgr, i, limits[i] + 1);
+		fail_if(acquired,
+				"Acquired reference exceeding limit of context kind %d", i);
+
+		/* Reset test variable */
+		acquired = false;
+	}
+
+	idmgr->destroy(idmgr);
+}
+END_TEST
+
 START_TEST(test_release_id)
 {
 	int i, id = 0;
@@ -150,6 +215,9 @@ Suite *make_id_manager_tests()
 	tcase_add_test(tc, test_acquire_id);
 	tcase_add_test(tc, test_acquire_id_invalid_kind);
 	tcase_add_test(tc, test_acquire_id_same);
+	tcase_add_test(tc, test_acquire_ref);
+	tcase_add_test(tc, test_acquire_ref_invalid_kind);
+	tcase_add_test(tc, test_acquire_ref_invalid_id);
 	suite_add_tcase(s, tc);
 
 	tc = tcase_create("release");