Fix our check for the "first" bridge descriptor.

This is meant to be a better bug 9229 fix -- or at least, one more
in tune with the intent of the original code, which calls
router_retry_directory_downloads() only on the first bridge descriptor.

changes/bug9229_025

@@ -0,0 +1,5 @@
+  o Minor bugfixes:
+    - Avoid 60-second delays in the bootstrapping process when Tor
+      is launching for a second time while using bridges. Fixes bug 9229;
+      bugfix on 0.2.0.3-alpha.
+

src/or/entrynodes.c

@@ -70,7 +70,9 @@ static int entry_guards_dirty = 0;
 static void bridge_free(bridge_info_t *bridge);
 static const node_t *choose_random_entry_impl(cpath_build_state_t *state,
                                               int for_directory,
-                                              dirinfo_type_t dirtype);
+                                              dirinfo_type_t dirtype,
+                                              int *n_options_out);
+static int num_bridges_usable(void);
 
 /** Return the list of entry guards, creating it if necessary. */
 const smartlist_t *
@@ -982,7 +984,7 @@ node_can_handle_dirinfo(const node_t *node, dirinfo_type_t dirinfo)
 const node_t *
 choose_random_entry(cpath_build_state_t *state)
 {
-  return choose_random_entry_impl(state, 0, 0);
+  return choose_random_entry_impl(state, 0, 0, NULL);
 }
 
 /** Pick a live (up and listed) directory guard from entry_guards for
@@ -990,13 +992,13 @@ choose_random_entry(cpath_build_state_t *state)
 const node_t *
 choose_random_dirguard(dirinfo_type_t type)
 {
-  return choose_random_entry_impl(NULL, 1, type);
+  return choose_random_entry_impl(NULL, 1, type, NULL);
 }
 
 /** Helper for choose_random{entry,dirguard}. */
 static const node_t *
 choose_random_entry_impl(cpath_build_state_t *state, int for_directory,
-                         dirinfo_type_t dirinfo_type)
+                         dirinfo_type_t dirinfo_type, int *n_options_out)
 {
   const or_options_t *options = get_options();
   smartlist_t *live_entry_guards = smartlist_new();
@@ -1010,6 +1012,9 @@ choose_random_entry_impl(cpath_build_state_t *state, int for_directory,
   int need_descriptor = !for_directory;
   const int num_needed = decide_num_guards(options, for_directory);
 
+  if (n_options_out)
+    n_options_out = 0;
+
   if (chosen_exit) {
     nodelist_add_node_and_family(exit_family, chosen_exit);
     consider_exit_family = 1;
@@ -1136,6 +1141,8 @@ choose_random_entry_impl(cpath_build_state_t *state, int for_directory,
      * *double*-weight our guard selection. */
     node = smartlist_choose(live_entry_guards);
   }
+  if (n_options_out)
+    *n_options_out = smartlist_len(live_entry_guards);
   smartlist_free(live_entry_guards);
   smartlist_free(exit_family);
   return node;
@@ -2166,7 +2173,7 @@ learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
   tor_assert(ri);
   tor_assert(ri->purpose == ROUTER_PURPOSE_BRIDGE);
   if (get_options()->UseBridges) {
-    int first = !any_bridge_descriptors_known();
+    int first = num_bridges_usable() <= 1;
     bridge_info_t *bridge = get_configured_bridge_by_routerinfo(ri);
     time_t now = time(NULL);
     router_set_status(ri->cache_info.identity_digest, 1);
@@ -2188,14 +2195,15 @@ learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
        * our entry node list */
       entry_guard_register_connect_status(ri->cache_info.identity_digest,
                                           1, 0, now);
-      if (first)
+      if (first) {
         routerlist_retry_directory_downloads(now);
+      }
     }
   }
 }
 
-/** Return 1 if any of our entry guards have descriptors that
+/** Return the number of bridges that have descriptors that
- * are marked with purpose 'bridge' and are running. Else return 0.
+ * are marked with purpose 'bridge' and are running.
  *
  * We use this function to decide if we're ready to start building
  * circuits through our bridges, or if we need to wait until the
@@ -2207,6 +2215,18 @@ any_bridge_descriptors_known(void)
   return choose_random_entry(NULL) != NULL;
 }
 
+/** Return the number of bridges that have descriptors that
+ * are marked with purpose 'bridge' and are running.
+ */
+static int
+num_bridges_usable(void)
+{
+  int n_options = 0;
+  tor_assert(get_options()->UseBridges);
+  (void) choose_random_entry_impl(NULL, 0, 0, &n_options);
+  return n_options == 1;
+}
+
 /** Return 1 if there are any directory conns fetching bridge descriptors
  * that aren't marked for close. We use this to guess if we should tell
  * the controller that we have a problem. */