Separate lookup function for service rend cache

Performing lookups in both the client and service side descriptor
caches from the same rend_cache_lookup_entry() function increases the
risk of accidental API misuse.

I'm separating the lookup functions to keep the caches distinct.

src/or/connection_edge.c

@@ -1527,8 +1527,7 @@ connection_ap_handshake_rewrite_and_attach(entry_connection_t *conn,
     unsigned int refetch_desc = 0;
     rend_cache_entry_t *entry = NULL;
     const int rend_cache_lookup_result =
-      rend_cache_lookup_entry(rend_data->onion_address, -1, &entry,
-                              REND_CACHE_TYPE_CLIENT);
+      rend_cache_lookup_entry(rend_data->onion_address, -1, &entry);
     if (rend_cache_lookup_result < 0) {
       switch (-rend_cache_lookup_result) {
       case EINVAL:

src/or/control.c

@@ -1920,7 +1920,7 @@ getinfo_helper_dir(control_connection_t *control_conn,
       return -1;
     }
 
-    if (!rend_cache_lookup_entry(question, -1, &e, REND_CACHE_TYPE_CLIENT)) {
+    if (!rend_cache_lookup_entry(question, -1, &e)) {
       /* Descriptor found in cache */
       *answer = tor_strdup(e->desc);
     } else {
@@ -1936,7 +1936,7 @@ getinfo_helper_dir(control_connection_t *control_conn,
       return -1;
     }
 
-    if (!rend_cache_lookup_entry(question, -1, &e, REND_CACHE_TYPE_SERVICE)) {
+    if (!rend_cache_lookup_v2_desc_as_service(question, &e)) {
       /* Descriptor found in cache */
       *answer = tor_strdup(e->desc);
     } else {

src/or/rendcache.c

@@ -480,27 +480,23 @@ rend_cache_clean_v2_descs_as_dir(time_t now, size_t force_remove)
   } while (bytes_removed < force_remove);
 }
 
-/** Lookup in the client or service cache the given service ID <b>query</b> for
- * <b>version</b>. The <b>service</b> argument determines if the lookup should
- * be from the client cache or the service cache.
+/** Lookup in the client cache the given service ID <b>query</b> for
+ * <b>version</b>.
  *
  * Return 0 if found and if <b>e</b> is non NULL, set it with the entry
  * found. Else, a negative value is returned and <b>e</b> is untouched.
  * -EINVAL means that <b>query</b> is not a valid service id.
  * -ENOENT means that no entry in the cache was found. */
 int
-rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e,
-                        rend_cache_type_t cache)
+rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e)
 {
   int ret = 0;
   char key[REND_SERVICE_ID_LEN_BASE32 + 2]; /* <version><query>\0 */
   rend_cache_entry_t *entry = NULL;
   static const int default_version = 2;
 
-  tor_assert(rend_cache_local_service);
   tor_assert(rend_cache);
   tor_assert(query);
-  tor_assert(cache);
 
   if (!rend_valid_service_id(query)) {
     ret = -EINVAL;
@@ -514,21 +510,50 @@ rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e,
     case 2:
       /* Default is version 2. */
     default:
-      if(cache == REND_CACHE_TYPE_SERVICE){
-        entry = strmap_get_lc(rend_cache_local_service, query);
-      } else if (cache == REND_CACHE_TYPE_CLIENT)  {
-        tor_snprintf(key, sizeof(key), "%d%s", default_version, query);
-        entry = strmap_get_lc(rend_cache, key);
-      }
+      tor_snprintf(key, sizeof(key), "%d%s", default_version, query);
+      entry = strmap_get_lc(rend_cache, key);
       break;
   }
   if (!entry) {
     ret = -ENOENT;
     goto end;
   }
-  /* Check descriptor is parsed only if lookup is from client cache */
-  if(cache == REND_CACHE_TYPE_CLIENT){
-    tor_assert(entry->parsed && entry->parsed->intro_nodes);
+  tor_assert(entry->parsed && entry->parsed->intro_nodes);
+
+  if (e) {
+    *e = entry;
+  }
+
+ end:
+  return ret;
+}
+
+/*
+ * Lookup the v2 service descriptor with the service ID <b>query</b> in the
+ * local service descriptor cache. Return 0 if found and if <b>e</b> is
+ * non NULL, set it with the entry found. Else, a negative value is returned
+ * and <b>e</b> is untouched.
+ * -EINVAL means that <b>query</b> is not a valid service id.
+ * -ENOENT means that no entry in the cache was found. */
+int
+rend_cache_lookup_v2_desc_as_service(const char *query, rend_cache_entry_t **e)
+{
+  int ret = 0;
+  rend_cache_entry_t *entry = NULL;
+
+  tor_assert(rend_cache_local_service);
+  tor_assert(query);
+
+  if (!rend_valid_service_id(query)) {
+    ret = -EINVAL;
+    goto end;
+  }
+
+  /* Lookup descriptor and return. */
+  entry = strmap_get_lc(rend_cache_local_service, query);
+  if (!entry) {
+    ret = -ENOENT;
+    goto end;
   }
 
   if (e) {

src/or/rendcache.h

@@ -60,8 +60,9 @@ void rend_cache_clean_v2_descs_as_dir(time_t now, size_t min_to_remove);
 void rend_cache_purge(void);
 void rend_cache_free_all(void);
 int rend_cache_lookup_entry(const char *query, int version,
-                            rend_cache_entry_t **entry_out,
-                            rend_cache_type_t cache);
+                            rend_cache_entry_t **entry_out);
+int rend_cache_lookup_v2_desc_as_service(const char *query,
+                                         rend_cache_entry_t **entry_out);
 int rend_cache_lookup_v2_desc_as_dir(const char *query, const char **desc);
 /** Return value from rend_cache_store_v2_desc_as_{dir,client}. */
 typedef enum {

src/or/rendclient.c

@@ -160,7 +160,7 @@ rend_client_send_introduction(origin_circuit_t *introcirc,
 #endif
 
   r = rend_cache_lookup_entry(introcirc->rend_data->onion_address, -1,
-                              &entry, REND_CACHE_TYPE_CLIENT);
+                              &entry);
   /* An invalid onion address is not possible else we have a big issue. */
   tor_assert(r != -EINVAL);
   if (r < 0 || !rend_client_any_intro_points_usable(entry)) {
@@ -906,8 +906,7 @@ rend_client_refetch_v2_renddesc(rend_data_t *rend_query)
     return;
   }
   /* Before fetching, check if we already have a usable descriptor here. */
-  if (rend_cache_lookup_entry(rend_query->onion_address, -1, &e,
-                              REND_CACHE_TYPE_CLIENT) == 0 &&
+  if (rend_cache_lookup_entry(rend_query->onion_address, -1, &e) == 0 &&
       rend_client_any_intro_points_usable(e)) {
     log_info(LD_REND, "We would fetch a v2 rendezvous descriptor, but we "
                       "already have a usable descriptor here. Not fetching.");
@@ -988,8 +987,7 @@ rend_client_report_intro_point_failure(extend_info_t *failed_intro,
   rend_cache_entry_t *ent;
   connection_t *conn;
 
-  r = rend_cache_lookup_entry(rend_query->onion_address, -1, &ent,
-                              REND_CACHE_TYPE_CLIENT);
+  r = rend_cache_lookup_entry(rend_query->onion_address, -1, &ent);
   if (r < 0) {
     /* Either invalid onion address or cache entry not found. */
     switch (-r) {
@@ -1215,7 +1213,7 @@ rend_client_desc_trynow(const char *query)
       continue;
     assert_connection_ok(base_conn, now);
     if (rend_cache_lookup_entry(rend_data->onion_address, -1,
-                                &entry, REND_CACHE_TYPE_CLIENT) == 0 &&
+                                &entry) == 0 &&
         rend_client_any_intro_points_usable(entry)) {
       /* either this fetch worked, or it failed but there was a
        * valid entry from before which we should reuse */
@@ -1258,7 +1256,7 @@ rend_client_note_connection_attempt_ended(const rend_data_t *rend_data)
   if (*rend_data->onion_address != '\0') {
     /* Ignore return value; we find an entry, or we don't. */
     (void) rend_cache_lookup_entry(rend_data->onion_address, -1,
-                                   &cache_entry, 0);
+                                   &cache_entry);
     have_onion = 1;
   }
 
@@ -1297,8 +1295,7 @@ rend_client_get_random_intro(const rend_data_t *rend_query)
   extend_info_t *result;
   rend_cache_entry_t *entry;
 
-  ret = rend_cache_lookup_entry(rend_query->onion_address, -1, &entry,
-                                REND_CACHE_TYPE_CLIENT);
+  ret = rend_cache_lookup_entry(rend_query->onion_address, -1, &entry);
   if (ret < 0 || !rend_client_any_intro_points_usable(entry)) {
     log_warn(LD_REND,
              "Query '%s' didn't have valid rend desc in cache. Failing.",