hs-v3: Implement hs_ob_service_is_instance()

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/feature/hs/hs_cell.c

@@ -916,7 +916,7 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
    * file. This is because the master identity key and the blinded key is put
    * in the INTRODUCE2 cell by the client thus it will never validate with
    * this instance default public key. */
-  if (service->config.ob_master_pubkeys) {
+  if (hs_ob_service_is_instance(service)) {
     intro_keys = get_intro2_keys_as_ob(&service->config, data,
                                        encrypted_section,
                                        encrypted_section_len);

src/feature/hs/hs_ob.c

@@ -193,6 +193,24 @@ build_subcredential(const ed25519_public_key_t *pkey, uint64_t tp,
  * Public API.
  */
 
+/** Return true iff the given service is configured as an onion balance
+ * instance. To satisfy that condition, there must at least be one master
+ * ed25519 public key configured. */
+bool
+hs_ob_service_is_instance(const hs_service_t *service)
+{
+  if (BUG(service == NULL)) {
+    return false;
+  }
+
+  /* No list, we are not an instance. */
+  if (!service->config.ob_master_pubkeys) {
+    return false;
+  }
+
+  return smartlist_len(service->config.ob_master_pubkeys) > 0;
+}
+
 /** Read and parse the config file at fname on disk. The service config object
  * is populated with the options if any.
  *

src/feature/hs/hs_ob.h

@@ -11,6 +11,8 @@
 
 #include "hs_service.h"
 
+bool hs_ob_service_is_instance(const hs_service_t *service);
+
 int hs_ob_parse_config_file(hs_service_config_t *config);
 
 size_t hs_ob_get_subcredentials(const hs_service_config_t *config,