charon-tkm: Add get_other_esa_id function to TKM kernel SAD

The function gets the ESA id for another entry associated with the same
security policy as the specified ESA.

src/charon-tkm/src/tkm/tkm_kernel_sad.c

@@ -126,6 +126,26 @@ static bool sad_entry_match_dst(sad_entry_t * const entry,
 		   entry->proto == *proto;
 }
 
+/**
+ * Find a list entry with given esa id.
+ */
+static bool sad_entry_match_esa_id(sad_entry_t * const entry,
+								   const esa_id_type * const esa_id)
+{
+	return entry->esa_id == *esa_id;
+}
+
+/**
+ * Find a list entry with given reqid and different esa id.
+ */
+static bool sad_entry_match_other_esa(sad_entry_t * const entry,
+									  const esa_id_type * const esa_id,
+									  const u_int32_t * const reqid)
+{
+	return entry->reqid  == *reqid &&
+		   entry->esa_id != *esa_id;
+}
+
 /**
  * Compare two SAD entries for equality.
  */
@@ -209,6 +229,42 @@ METHOD(tkm_kernel_sad_t, get_esa_id, esa_id_type,
 	return id;
 }
 
+METHOD(tkm_kernel_sad_t, get_other_esa_id, esa_id_type,
+	private_tkm_kernel_sad_t * const this, const esa_id_type esa_id)
+{
+	esa_id_type id = 0;
+	sad_entry_t *entry = NULL;
+	u_int32_t reqid;
+	status_t res;
+
+	this->mutex->lock(this->mutex);
+	res = this->data->find_first(this->data,
+								 (linked_list_match_t)sad_entry_match_esa_id,
+								 (void**)&entry, &esa_id);
+	if (res == SUCCESS && entry)
+	{
+		reqid = entry->reqid;
+	}
+	else
+	{
+		DBG3(DBG_KNL, "no SAD entry found for ESA id %llu", esa_id);
+		this->mutex->unlock(this->mutex);
+		return id;
+	}
+
+	res = this->data->find_first(this->data,
+								 (linked_list_match_t)sad_entry_match_other_esa,
+								 (void**)&entry, &esa_id, &reqid);
+	if (res == SUCCESS && entry)
+	{
+		id = entry->esa_id;
+		DBG3(DBG_KNL, "returning ESA id %llu of other SAD entry with reqid %u",
+			 id, reqid);
+	}
+	this->mutex->unlock(this->mutex);
+	return id;
+}
+
 METHOD(tkm_kernel_sad_t, get_dst_host, host_t *,
 	private_tkm_kernel_sad_t * const this, const u_int32_t reqid,
 	const u_int32_t spi, const u_int8_t proto)
@@ -289,6 +345,7 @@ tkm_kernel_sad_t *tkm_kernel_sad_create()
 		.public = {
 			.insert = _insert,
 			.get_esa_id = _get_esa_id,
+			.get_other_esa_id = _get_other_esa_id,
 			.get_dst_host = _get_dst_host,
 			.remove = __remove,
 			.destroy = _destroy,

src/charon-tkm/src/tkm/tkm_kernel_sad.h

@@ -62,6 +62,16 @@ struct tkm_kernel_sad_t {
 				 const host_t * const src, const host_t * const dst,
 				 const u_int32_t spi, const u_int8_t proto);
 
+	/**
+	 * Get ESA id for entry associated with same security policy as the
+	 * specified ESA.
+	 *
+	 * @param esa_id		id of ESA identifying the security policy
+	 * @return				ESA id of entry if found, 0 otherwise
+	 */
+	esa_id_type (*get_other_esa_id)(tkm_kernel_sad_t * const this,
+									const esa_id_type esa_id);
+
 	/**
 	 * Get destination host for entry with given parameters.
 	 *

src/charon-tkm/tests/kernel_sad_tests.c

@@ -81,6 +81,37 @@ START_TEST(test_get_esa_id_nonexistent)
 }
 END_TEST
 
+START_TEST(test_get_other_esa_id)
+{
+	host_t *addr = host_create_from_string("127.0.0.1", 1024);
+	tkm_kernel_sad_t *sad = tkm_kernel_sad_create();
+	fail_unless(sad->insert(sad, 23, 54, addr, addr, 42, 50),
+				"Error inserting SAD entry");
+	fail_unless(sad->insert(sad, 24, 54, addr, addr, 42, 50),
+				"Error inserting SAD entry");
+	fail_unless(sad->get_other_esa_id(sad, 23) == 24,
+				"Error getting other esa id");
+	sad->destroy(sad);
+	addr->destroy(addr);
+}
+END_TEST
+
+START_TEST(test_get_other_esa_id_nonexistent)
+{
+	host_t *addr = host_create_from_string("127.0.0.1", 1024);
+	tkm_kernel_sad_t *sad = tkm_kernel_sad_create();
+	fail_unless(sad->get_other_esa_id(sad, 1) == 0,
+				"Got other esa id for nonexistent SAD entry");
+	fail_unless(sad->insert(sad, 23, 54, addr, addr, 42, 50),
+				"Error inserting SAD entry");
+	fail_unless(sad->get_other_esa_id(sad, 23) == 0,
+				"Got own esa id");
+
+	sad->destroy(sad);
+	addr->destroy(addr);
+}
+END_TEST
+
 START_TEST(test_get_dst_host)
 {
 	host_t *addr = host_create_from_string("127.0.0.1", 1024);
@@ -151,6 +182,11 @@ Suite *make_kernel_sad_tests()
 	tcase_add_test(tc, test_get_esa_id_nonexistent);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("get_other_esa_id");
+	tcase_add_test(tc, test_get_other_esa_id);
+	tcase_add_test(tc, test_get_other_esa_id_nonexistent);
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("get_dst_host");
 	tcase_add_test(tc, test_get_dst_host);
 	tcase_add_test(tc, test_get_dst_host_nonexistent);