ipsec-types: Move allocation of unique interface IDs to helper function

src/libcharon/sa/child_sa.c

@@ -1793,7 +1793,7 @@ child_sa_t * child_sa_create(host_t *me, host_t* other,
 							 uint32_t if_id_in, uint32_t if_id_out)
 {
 	private_child_sa_t *this;
-	static refcount_t unique_id = 0, unique_mark = 0, unique_if_id = 0;
+	static refcount_t unique_id = 0, unique_mark = 0;
 
 	INIT(this,
 		.public = {
@@ -1878,6 +1878,8 @@ child_sa_t * child_sa_create(host_t *me, host_t* other,
 		this->if_id_out = if_id_out;
 	}
 
+	allocate_unique_if_ids(&this->if_id_in, &this->if_id_out);
+
 	if (MARK_IS_UNIQUE(this->mark_in.value) ||
 		MARK_IS_UNIQUE(this->mark_out.value))
 	{
@@ -1899,27 +1901,6 @@ child_sa_t * child_sa_create(host_t *me, host_t* other,
 		}
 	}
 
-	if (IF_ID_IS_UNIQUE(this->if_id_in) ||
-		IF_ID_IS_UNIQUE(this->if_id_out))
-	{
-		refcount_t if_id = 0;
-		bool unique_dir = this->if_id_in == IF_ID_UNIQUE_DIR ||
-						  this->if_id_out == IF_ID_UNIQUE_DIR;
-
-		if (!unique_dir)
-		{
-			if_id = ref_get(&unique_if_id);
-		}
-		if (IF_ID_IS_UNIQUE(this->if_id_in))
-		{
-			this->if_id_in = unique_dir ? ref_get(&unique_if_id) : if_id;
-		}
-		if (IF_ID_IS_UNIQUE(this->if_id_out))
-		{
-			this->if_id_out = unique_dir ? ref_get(&unique_if_id) : if_id;
-		}
-	}
-
 	if (!this->reqid)
 	{
 		/* reuse old reqid if we are rekeying an existing CHILD_SA and when

src/libstrongswan/ipsec/ipsec_types.c

@@ -149,7 +149,7 @@ bool mark_from_string(const char *value, mark_op_t ops, mark_t *mark)
 }
 
 /*
- * See header
+ * Described in header
  */
 bool if_id_from_string(const char *value, uint32_t *if_id)
 {
@@ -188,3 +188,31 @@ bool if_id_from_string(const char *value, uint32_t *if_id)
 	}
 	return TRUE;
 }
+
+/*
+ * Described in header
+ */
+void allocate_unique_if_ids(uint32_t *in, uint32_t *out)
+{
+	static refcount_t unique_if_id = 0;
+
+	if (IF_ID_IS_UNIQUE(*in) || IF_ID_IS_UNIQUE(*out))
+	{
+		refcount_t if_id = 0;
+		bool unique_dir = *in == IF_ID_UNIQUE_DIR ||
+						  *out == IF_ID_UNIQUE_DIR;
+
+		if (!unique_dir)
+		{
+			if_id = ref_get(&unique_if_id);
+		}
+		if (IF_ID_IS_UNIQUE(*in))
+		{
+			*in = unique_dir ? ref_get(&unique_if_id) : if_id;
+		}
+		if (IF_ID_IS_UNIQUE(*out))
+		{
+			*out = unique_dir ? ref_get(&unique_if_id) : if_id;
+		}
+	}
+}

src/libstrongswan/ipsec/ipsec_types.h

@@ -256,4 +256,12 @@ bool mark_from_string(const char *value, mark_op_t ops, mark_t *mark);
  */
 bool if_id_from_string(const char *value, uint32_t *if_id);
 
+/**
+ * Allocate up to two unique interface IDs depending on the given values.
+ *
+ * @param[out] in	inbound interface ID
+ * @param[out] out	outbound interface ID
+ */
+void allocate_unique_if_ids(uint32_t *in, uint32_t *out);
+
 #endif /** IPSEC_TYPES_H_ @}*/

src/libstrongswan/tests/suites/test_utils.c

@@ -983,6 +983,41 @@ START_TEST(test_if_id_from_string)
 }
 END_TEST
 
+/*******************************************************************************
+ * allocate_unique_if_ids
+ */
+
+static struct {
+	uint32_t in;
+	uint32_t out;
+	uint32_t exp_in;
+	uint32_t exp_out;
+} unique_if_id_data[] = {
+	{0,	0, 0, 0 },
+	{42, 42, 42, 42 },
+	{42, 1337, 42, 1337 },
+	/* each call increases the internal counter by 1 or 2*/
+	{IF_ID_UNIQUE, 42, 1, 42 },
+	{42, IF_ID_UNIQUE, 42, 2 },
+	{IF_ID_UNIQUE_DIR, 42, 3, 42 },
+	{42, IF_ID_UNIQUE_DIR, 42, 4 },
+	{IF_ID_UNIQUE, IF_ID_UNIQUE, 5, 5 },
+	{IF_ID_UNIQUE_DIR, IF_ID_UNIQUE, 6, 7 },
+	{IF_ID_UNIQUE, IF_ID_UNIQUE_DIR, 8, 9 },
+	{IF_ID_UNIQUE_DIR, IF_ID_UNIQUE_DIR, 10, 11 },
+};
+
+START_TEST(test_allocate_unique_if_ids)
+{
+	uint32_t if_id_in = unique_if_id_data[_i].in,
+			 if_id_out = unique_if_id_data[_i].out;
+
+	allocate_unique_if_ids(&if_id_in, &if_id_out);
+	ck_assert_int_eq(if_id_in, unique_if_id_data[_i].exp_in);
+	ck_assert_int_eq(if_id_out, unique_if_id_data[_i].exp_out);
+}
+END_TEST
+
 /*******************************************************************************
  * signature_schemes_for_key
  */
@@ -1134,6 +1169,10 @@ Suite *utils_suite_create()
 	tcase_add_loop_test(tc, test_if_id_from_string, 0, countof(if_id_data));
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("allocate_unique_if_ids");
+	tcase_add_loop_test(tc, test_allocate_unique_if_ids, 0, countof(unique_if_id_data));
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("signature_schemes_for_key");
 	tcase_add_loop_test(tc, test_signature_schemes_for_key, 0, countof(scheme_data));
 	suite_add_tcase(s, tc);