Fix compute_frac_paths_available, when ExitNodes is not set.

changes/bug14918

@@ -5,3 +5,6 @@
     - Do not warn that we are missing directory information if we have
       decided not to fetch directory information due to a long period
       of idleness. Fixes part of bug 14918; bugfix on 0.2.6.2-alpha.
+    - When deciding whether we have any exit nodes, only do processing for
+      ExitNodes when the ExitNodes option is actually set. Fixes part of
+      bug 14918; bugfix on 0.2.6.2-alpha.

src/or/nodelist.c

@@ -1430,9 +1430,7 @@ compute_frac_paths_available(const networkstatus_t *consensus,
   smartlist_t *guards = smartlist_new();
   smartlist_t *mid    = smartlist_new();
   smartlist_t *exits  = smartlist_new();
-  smartlist_t *myexits= smartlist_new();
-  smartlist_t *myexits_unflagged = smartlist_new();
-  double f_guard, f_mid, f_exit, f_myexit, f_myexit_unflagged;
+  double f_guard, f_mid, f_exit;
   double f_path = 0.0;
   /* Used to determine whether there are any exits in the consensus */
   int np = 0;
@@ -1494,75 +1492,89 @@ compute_frac_paths_available(const networkstatus_t *consensus,
      * browsing (as distinct from hidden service web browsing). */
   }
 
-  /* All nodes with exit flag in ExitNodes option */
-  count_usable_descriptors(&np, &nu, myexits, consensus, options, now,
-                           options->ExitNodes, USABLE_DESCRIPTOR_EXIT_ONLY);
-  log_debug(LD_NET,
-            "%s: %d present, %d usable",
-            "myexits",
-            np,
-            nu);
-
-  /* Now compute the nodes in the ExitNodes option where which we don't know
-   * what their exit policy is, or we know it permits something. */
-  count_usable_descriptors(&np, &nu, myexits_unflagged,
-                           consensus, options, now,
-                           options->ExitNodes, USABLE_DESCRIPTOR_ALL);
-  log_debug(LD_NET,
-            "%s: %d present, %d usable",
-            "myexits_unflagged (initial)",
-            np,
-            nu);
-
-  SMARTLIST_FOREACH_BEGIN(myexits_unflagged, const node_t *, node) {
-    if (node_has_descriptor(node) && node_exit_policy_rejects_all(node)) {
-      SMARTLIST_DEL_CURRENT(myexits_unflagged, node);
-      /* this node is not actually an exit */
-      np--;
-      /* this node is unusable as an exit */
-      nu--;
-    }
-  } SMARTLIST_FOREACH_END(node);
-
-  log_debug(LD_NET,
-            "%s: %d present, %d usable",
-            "myexits_unflagged (final)",
-            np,
-            nu);
-
   f_guard = frac_nodes_with_descriptors(guards, WEIGHT_FOR_GUARD);
   f_mid   = frac_nodes_with_descriptors(mid,    WEIGHT_FOR_MID);
   f_exit  = frac_nodes_with_descriptors(exits,  WEIGHT_FOR_EXIT);
-  f_myexit= frac_nodes_with_descriptors(myexits,WEIGHT_FOR_EXIT);
-  f_myexit_unflagged=
-            frac_nodes_with_descriptors(myexits_unflagged,WEIGHT_FOR_EXIT);
 
   log_debug(LD_NET,
-            "f_exit: %.2f, f_myexit: %.2f, f_myexit_unflagged: %.2f",
-            f_exit,
-            f_myexit,
-            f_myexit_unflagged);
-
-  /* If our ExitNodes list has eliminated every possible Exit node, and there
-   * were some possible Exit nodes, then instead consider nodes that permit
-   * exiting to some ports. */
-  if (smartlist_len(myexits) == 0 &&
-      smartlist_len(myexits_unflagged)) {
-    f_myexit = f_myexit_unflagged;
-  }
+            "f_guard: %.2f, f_mid: %.2f, f_exit: %.2f",
+             f_guard,
+             f_mid,
+             f_exit);
 
   smartlist_free(guards);
   smartlist_free(mid);
   smartlist_free(exits);
-  smartlist_free(myexits);
-  smartlist_free(myexits_unflagged);
-
-  /* This is a tricky point here: we don't want to make it easy for a
-   * directory to trickle exits to us until it learns which exits we have
-   * configured, so require that we have a threshold both of total exits
-   * and usable exits. */
-  if (f_myexit < f_exit)
-    f_exit = f_myexit;
+
+  if (options->ExitNodes) {
+    double f_myexit, f_myexit_unflagged;
+    smartlist_t *myexits= smartlist_new();
+    smartlist_t *myexits_unflagged = smartlist_new();
+
+    /* All nodes with exit flag in ExitNodes option */
+    count_usable_descriptors(&np, &nu, myexits, consensus, options, now,
+                             options->ExitNodes, USABLE_DESCRIPTOR_EXIT_ONLY);
+    log_debug(LD_NET,
+              "%s: %d present, %d usable",
+              "myexits",
+              np,
+              nu);
+
+    /* Now compute the nodes in the ExitNodes option where which we don't know
+     * what their exit policy is, or we know it permits something. */
+    count_usable_descriptors(&np, &nu, myexits_unflagged,
+                             consensus, options, now,
+                             options->ExitNodes, USABLE_DESCRIPTOR_ALL);
+    log_debug(LD_NET,
+              "%s: %d present, %d usable",
+              "myexits_unflagged (initial)",
+              np,
+              nu);
+
+    SMARTLIST_FOREACH_BEGIN(myexits_unflagged, const node_t *, node) {
+      if (node_has_descriptor(node) && node_exit_policy_rejects_all(node)) {
+        SMARTLIST_DEL_CURRENT(myexits_unflagged, node);
+        /* this node is not actually an exit */
+        np--;
+        /* this node is unusable as an exit */
+        nu--;
+      }
+    } SMARTLIST_FOREACH_END(node);
+
+    log_debug(LD_NET,
+              "%s: %d present, %d usable",
+              "myexits_unflagged (final)",
+              np,
+              nu);
+
+    f_myexit= frac_nodes_with_descriptors(myexits,WEIGHT_FOR_EXIT);
+    f_myexit_unflagged=
+              frac_nodes_with_descriptors(myexits_unflagged,WEIGHT_FOR_EXIT);
+
+    log_debug(LD_NET,
+              "f_exit: %.2f, f_myexit: %.2f, f_myexit_unflagged: %.2f",
+              f_exit,
+              f_myexit,
+              f_myexit_unflagged);
+
+    /* If our ExitNodes list has eliminated every possible Exit node, and there
+     * were some possible Exit nodes, then instead consider nodes that permit
+     * exiting to some ports. */
+    if (smartlist_len(myexits) == 0 &&
+        smartlist_len(myexits_unflagged)) {
+      f_myexit = f_myexit_unflagged;
+    }
+
+    smartlist_free(myexits);
+    smartlist_free(myexits_unflagged);
+
+    /* This is a tricky point here: we don't want to make it easy for a
+     * directory to trickle exits to us until it learns which exits we have
+     * configured, so require that we have a threshold both of total exits
+     * and usable exits. */
+    if (f_myexit < f_exit)
+      f_exit = f_myexit;
+  }
 
   /* if the consensus has no exits, treat the exit fraction as 100% */
   if (router_have_consensus_path() != CONSENSUS_PATH_EXIT) {