Merge remote-tracking branch 'asn/bug23670'

changes/bug23670

+  o Minor features (entry guards):
+    - Improve logs issued when we are missing descriptors of primary guards.
+      Resolves ticket 23670.

src/or/entrynodes.c

@@ -3440,15 +3440,20 @@ guards_retry_optimistic(const or_options_t *options)
 }
 
 /**
- * Return true iff we know enough directory information to construct
- * circuits through all of the primary guards we'd currently use.
- */
-int
-guard_selection_have_enough_dir_info_to_build_circuits(guard_selection_t *gs)
+ * Check if we are missing any crucial dirinfo for the guard subsystem to
+ * work. Return NULL if everything went well, otherwise return a newly
+ * allocated string with an informative error message. In the latter case, use
+ * the genreal descriptor information <b>using_mds</b>, <b>num_present</b> and
+ * <b>num_usable</b> to improve the error message. */
+char *
+guard_selection_get_err_str_if_dir_info_missing(guard_selection_t *gs,
+                                        int using_mds,
+                                        int num_present, int num_usable)
 {
   if (!gs->primary_guards_up_to_date)
     entry_guards_update_primary(gs);
 
+  char *ret_str = NULL;
   int n_missing_descriptors = 0;
   int n_considered = 0;
   int num_primary_to_check;
@@ -3470,16 +3475,30 @@ guard_selection_have_enough_dir_info_to_build_circuits(guard_selection_t *gs)
       break;
   } SMARTLIST_FOREACH_END(guard);
 
-  return n_missing_descriptors == 0;
+  /* If we are not missing any descriptors, return NULL. */
+  if (!n_missing_descriptors) {
+    return NULL;
+  }
+
+  /* otherwise return a helpful error string */
+  tor_asprintf(&ret_str, "We're missing descriptors for %d/%d of our "
+               "primary entry guards (total %sdescriptors: %d/%d).",
+               n_missing_descriptors, num_primary_to_check,
+               using_mds?"micro":"", num_present, num_usable);
+
+  return ret_str;
 }
 
 /** As guard_selection_have_enough_dir_info_to_build_circuits, but uses
  * the default guard selection. */
-int
-entry_guards_have_enough_dir_info_to_build_circuits(void)
-{
-  return guard_selection_have_enough_dir_info_to_build_circuits(
-                                        get_guard_selection_info());
+char *
+entry_guards_get_err_str_if_dir_info_missing(int using_mds,
+                                     int num_present, int num_usable)
+{
+  return guard_selection_get_err_str_if_dir_info_missing(
+                                                 get_guard_selection_info(),
+                                                 using_mds,
+                                                 num_present, num_usable);
 }
 
 /** Free one guard selection context */

src/or/entrynodes.h

@@ -572,9 +572,11 @@ int getinfo_helper_entry_guards(control_connection_t *conn,
 int entries_known_but_down(const or_options_t *options);
 void entries_retry_all(const or_options_t *options);
 
-int guard_selection_have_enough_dir_info_to_build_circuits(
-                                                    guard_selection_t *gs);
-int entry_guards_have_enough_dir_info_to_build_circuits(void);
+char *entry_guards_get_err_str_if_dir_info_missing(int using_mds,
+                                           int num_present, int num_usable);
+char *guard_selection_get_err_str_if_dir_info_missing(guard_selection_t *gs,
+                                              int using_mds,
+                                              int num_present, int num_usable);
 
 void entry_guards_free_all(void);
 

src/or/nodelist.c

@@ -2282,6 +2282,7 @@ update_router_have_minimum_dir_info(void)
 {
   time_t now = time(NULL);
   int res;
+  int num_present=0, num_usable=0;
   const or_options_t *options = get_options();
   const networkstatus_t *consensus =
     networkstatus_get_reasonably_live_consensus(now,usable_consensus_flavor());
@@ -2300,17 +2301,9 @@ update_router_have_minimum_dir_info(void)
 
   using_md = consensus->flavor == FLAV_MICRODESC;
 
-  if (! entry_guards_have_enough_dir_info_to_build_circuits()) {
-    strlcpy(dir_info_status, "We're missing descriptors for some of our "
-            "primary entry guards", sizeof(dir_info_status));
-    res = 0;
-    goto done;
-  }
-
   /* Check fraction of available paths */
   {
     char *status = NULL;
-    int num_present=0, num_usable=0;
     double paths = compute_frac_paths_available(consensus, options, now,
                                                 &num_present, &num_usable,
                                                 &status);
@@ -2331,6 +2324,18 @@ update_router_have_minimum_dir_info(void)
     res = 1;
   }
 
+  { /* Check entry guard dirinfo status */
+    char *guard_error = entry_guards_get_err_str_if_dir_info_missing(using_md,
+                                                             num_present,
+                                                             num_usable);
+    if (guard_error) {
+      strlcpy(dir_info_status, guard_error, sizeof(dir_info_status));
+      tor_free(guard_error);
+      res = 0;
+      goto done;
+    }
+  }
+
  done:
 
   /* If paths have just become available in this update. */

src/test/test_entrynodes.c

@@ -1639,6 +1639,27 @@ test_entry_guard_manage_primary(void *arg)
     tt_ptr_op(g, OP_EQ, smartlist_get(prev_guards, g_sl_idx));
   });
 
+  /* Do some dirinfo checks */
+  {
+    /* Check that we have all required dirinfo for the primaries (that's done
+     * in big_fake_network_setup()) */
+    char *dir_info_str =
+      guard_selection_get_err_str_if_dir_info_missing(gs, 0, 0, 0);
+    tt_assert(!dir_info_str);
+
+    /* Now artificially remove the first primary's descriptor and re-check */
+    entry_guard_t *first_primary;
+    first_primary = smartlist_get(gs->primary_entry_guards, 0);
+    /* Change the first primary's identity digest so that the mocked functions
+     * can't find its descriptor */
+    memset(first_primary->identity, 9, sizeof(first_primary->identity));
+    dir_info_str =guard_selection_get_err_str_if_dir_info_missing(gs, 1, 2, 3);
+    tt_str_op(dir_info_str, OP_EQ,
+              "We're missing descriptors for 1/2 of our primary entry guards "
+              "(total microdescriptors: 2/3).");
+    tor_free(dir_info_str);
+  }
+
  done:
   guard_selection_free(gs);
   smartlist_free(prev_guards);