stats: Always publish pluggable transports in extra info documents

Always publish bridge pluggable transport information in the extra info
descriptor, even if ExtraInfoStatistics is 0. This information is
needed by BridgeDB.

Fixes bug 30956; bugfix on 0.4.1.1-alpha.

changes/bug30956

+  o Minor bugfixes (pluggable transports):
+    - Always publish bridge pluggable transport information in the extra info
+      descriptor, even if ExtraInfoStatistics is 0. This information is
+      needed by BridgeDB. Fixes bug 30956; bugfix on 0.4.1.1-alpha.

doc/tor.1.txt

@@ -2451,8 +2451,10 @@ is non-zero):
 [[ExtraInfoStatistics]] **ExtraInfoStatistics** **0**|**1**::
     When this option is enabled, Tor includes previously gathered statistics in
     its extra-info documents that it uploads to the directory authorities.
-    Disabling this option also disables bandwidth usage statistics, GeoIPFile
-    hashes, and ServerTransportPlugin lists in the extra-info file.
+    Disabling this option also removes bandwidth usage statistics, and
+    GeoIPFile and GeoIPv6File hashes from the extra-info file. Bridge
+    ServerTransportPlugin lines are always includes in the extra-info file,
+    because they are required by BridgeDB.
     (Default: 1)
 
 [[ExtendAllowPrivateAddresses]] **ExtendAllowPrivateAddresses** **0**|**1**::

src/feature/relay/router.c

@@ -3175,6 +3175,15 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
                published);
   smartlist_add(chunks, pre);
 
+  /* Add information about the pluggable transports we support, even if we
+   * are not publishing statistics. This information is needed by BridgeDB
+   * to distribute bridges. */
+  if (options->ServerTransportPlugin) {
+    char *pluggable_transports = pt_get_extra_info_descriptor_string();
+    if (pluggable_transports)
+      smartlist_add(chunks, pluggable_transports);
+  }
+
   if (options->ExtraInfoStatistics && write_stats_to_extrainfo) {
     log_info(LD_GENERAL, "Adding stats to extra-info descriptor.");
     /* Bandwidth usage stats don't have their own option */
@@ -3182,6 +3191,7 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
       contents = rep_hist_get_bandwidth_lines();
       smartlist_add(chunks, contents);
     }
+    /* geoip hashes aren't useful unless we are publishing other stats */
     if (geoip_is_loaded(AF_INET))
       smartlist_add_asprintf(chunks, "geoip-db-digest %s\n",
                              geoip_db_digest(AF_INET));
@@ -3223,12 +3233,7 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
       if (contents)
         smartlist_add(chunks, contents);
     }
-    /* Add information about the pluggable transports we support. */
-    if (options->ServerTransportPlugin) {
-      char *pluggable_transports = pt_get_extra_info_descriptor_string();
-      if (pluggable_transports)
-        smartlist_add(chunks, pluggable_transports);
-    }
+    /* bridge statistics */
     if (should_record_bridge_info(options)) {
       const char *bridge_stats = geoip_get_bridge_stats_extrainfo(now);
       if (bridge_stats) {