Make NumDirectoryGuards work with the new guard algorithm.

Now that we support NumEntryGuards, NumDirectoryGuards is pretty
easy to put back in.

3 files changed, 85 insertions, 39 deletions

diff --git a/src/or/entrynodes.c b/src/or/entrynodes.c
index 9defd11656..9416298ca3 100644
--- a/src/or/entrynodes.c
+++ b/src/or/entrynodes.c
@@ -472,10 +472,11 @@ STATIC int
 get_n_primary_guards(void)
 {
   const int n = get_options()->NumEntryGuards;
+  const int n_dir = get_options()->NumDirectoryGuards;
   if (n > 5) {
-    return n + n / 2;
-  } else if (n > 1) {
-    return n * 2;
+    return MAX(n_dir, n + n / 2);
+  } else if (n >= 1) {
+    return MAX(n_dir, n * 2);
   }
 
   return networkstatus_get_param(NULL,
@@ -487,14 +488,25 @@ get_n_primary_guards(void)
  * making a circuit.
  */
 STATIC int
-get_n_primary_guards_to_use(void)
-{
-  if (get_options()->NumEntryGuards > 1) {
-    return get_options()->NumEntryGuards;
+get_n_primary_guards_to_use(guard_usage_t usage)
+{
+  int configured;
+  const char *param_name;
+  int param_default;
+  if (usage == GUARD_USAGE_DIRGUARD) {
+    configured = get_options()->NumDirectoryGuards;
+    param_name = "guard-n-primary-dir-guards-to-use";
+    param_default = DFLT_N_PRIMARY_DIR_GUARDS_TO_USE;
+  } else {
+    configured = get_options()->NumEntryGuards;
+    param_name = "guard-n-primary-guards-to-use";
+    param_default = DFLT_N_PRIMARY_GUARDS_TO_USE;
+  }
+  if (configured >= 1) {
+    return configured;
   }
   return networkstatus_get_param(NULL,
-                                 "guard-n-primary-guards-to-use",
-                                 DFLT_N_PRIMARY_GUARDS_TO_USE, 1, INT32_MAX);
+                                 param_name, param_default, 1, INT32_MAX);
 }
 /**
  * If we haven't successfully built or used a circuit in this long, then
@@ -1807,6 +1819,7 @@ entry_guards_note_internet_connectivity(guard_selection_t *gs)
  */
 STATIC entry_guard_t *
 select_entry_guard_for_circuit(guard_selection_t *gs,
+                               guard_usage_t usage,
                                const entry_guard_restriction_t *rst,
                                unsigned *state_out)
 {
@@ -1817,7 +1830,7 @@ select_entry_guard_for_circuit(guard_selection_t *gs,
   if (!gs->primary_guards_up_to_date)
     entry_guards_update_primary(gs);
 
-  int num_entry_guards = get_n_primary_guards_to_use();
+  int num_entry_guards = get_n_primary_guards_to_use(usage);
   smartlist_t *usable_primary_guards = smartlist_new();
 
   /* "If any entry in PRIMARY_GUARDS has {is_reachable} status of
@@ -2080,6 +2093,7 @@ circuit_guard_state_free(circuit_guard_state_t *state)
  */
 int
 entry_guard_pick_for_circuit(guard_selection_t *gs,
+                             guard_usage_t usage,
                              entry_guard_restriction_t *rst,
                              const node_t **chosen_node_out,
                              circuit_guard_state_t **guard_state_out)
@@ -2091,7 +2105,8 @@ entry_guard_pick_for_circuit(guard_selection_t *gs,
   *guard_state_out = NULL;
 
   unsigned state = 0;
-  entry_guard_t *guard = select_entry_guard_for_circuit(gs, rst, &state);
+  entry_guard_t *guard =
+    select_entry_guard_for_circuit(gs, usage, rst, &state);
   if (! guard)
     goto fail;
   if (BUG(state == 0))
@@ -4986,6 +5001,7 @@ guards_choose_guard(cpath_build_state_t *state,
       memcpy(rst->exclude_id, exit_id, DIGEST_LEN);
     }
     if (entry_guard_pick_for_circuit(get_guard_selection_info(),
+                                     GUARD_USAGE_TRAFFIC,
                                      rst,
                                      &r,
                                      guard_state_out) < 0) {
@@ -5018,6 +5034,7 @@ guards_choose_dirguard(dirinfo_type_t info,
      * microdescriptors. -NM */
     const node_t *r = NULL;
     if (entry_guard_pick_for_circuit(get_guard_selection_info(),
+                                     GUARD_USAGE_DIRGUARD,
                                      NULL,
                                      &r,
                                      guard_state_out) < 0) {
diff --git a/src/or/entrynodes.h b/src/or/entrynodes.h
index e2ae2561f3..c215c103ca 100644
--- a/src/or/entrynodes.h
+++ b/src/or/entrynodes.h
@@ -397,8 +397,16 @@ const char *entry_guard_get_rsa_id_digest(const entry_guard_t *guard);
 const char *entry_guard_describe(const entry_guard_t *guard);
 guard_pathbias_t *entry_guard_get_pathbias_state(entry_guard_t *guard);
 
+/** Enum to specify how we're going to use a given guard, when we're picking
+ * one for immediate use. */
+typedef enum {
+  GUARD_USAGE_TRAFFIC = 0,
+  GUARD_USAGE_DIRGUARD = 1
+} guard_usage_t;
+
 void circuit_guard_state_free(circuit_guard_state_t *state);
 int entry_guard_pick_for_circuit(guard_selection_t *gs,
+                                 guard_usage_t usage,
                                  entry_guard_restriction_t *rst,
                                  const node_t **chosen_node_out,
                                  circuit_guard_state_t **guard_state_out);
@@ -477,6 +485,10 @@ int num_bridges_usable(void);
  */
 #define DFLT_N_PRIMARY_GUARDS_TO_USE 1
 /**
+ * As DFLT_N_PRIMARY_GUARDS, but for choosing which directory guard to use.
+ */
+#define DFLT_N_PRIMARY_DIR_GUARDS_TO_USE 3
+/**
  * If we haven't successfully built or used a circuit in this long, then
  * consider that the internet is probably down.
  */
@@ -511,7 +523,7 @@ STATIC int get_remove_unlisted_guards_after_days(void);
 STATIC int get_guard_lifetime(void);
 STATIC int get_guard_confirmed_min_lifetime(void);
 STATIC int get_n_primary_guards(void);
-STATIC int get_n_primary_guards_to_use(void);
+STATIC int get_n_primary_guards_to_use(guard_usage_t usage);
 STATIC int get_internet_likely_down_interval(void);
 STATIC int get_nonprimary_guard_connect_timeout(void);
 STATIC int get_nonprimary_guard_idle_timeout(void);
@@ -590,6 +602,7 @@ STATIC void sampled_guards_update_from_consensus(guard_selection_t *gs);
 STATIC void entry_guards_note_guard_failure(guard_selection_t *gs,
                                             entry_guard_t *guard);
 STATIC entry_guard_t *select_entry_guard_for_circuit(guard_selection_t *gs,
+                                          guard_usage_t usage,
                                           const entry_guard_restriction_t *rst,
                                           unsigned *state_out);
 STATIC void mark_primary_guards_maybe_reachable(guard_selection_t *gs);
diff --git a/src/test/test_entrynodes.c b/src/test/test_entrynodes.c
index 594708a12b..002411377c 100644
--- a/src/test/test_entrynodes.c
+++ b/src/test/test_entrynodes.c
@@ -2447,7 +2447,8 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
   entry_guards_update_primary(gs);
   unsigned state = 9999;
 
-  entry_guard_t *g = select_entry_guard_for_circuit(gs, NULL, &state);
+  entry_guard_t *g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC,
+                                                    NULL, &state);
 
   tt_assert(g);
   tt_assert(g->is_primary);
@@ -2457,7 +2458,8 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
   tt_i64_op(g->last_tried_to_connect, OP_EQ, approx_time());
 
   // If we do that again, we should get the same guard.
-  entry_guard_t *g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  entry_guard_t *g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC,
+                                                     NULL, &state);
   tt_ptr_op(g2, OP_EQ, g);
 
   // if we mark that guard down, we should get a different primary guard.
@@ -2466,7 +2468,7 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
   g->failing_since = approx_time() - 10;
   g->last_tried_to_connect = approx_time() - 10;
   state = 9999;
-  g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_ptr_op(g2, OP_NE, g);
   tt_assert(g2);
   tt_assert(g2->is_primary);
@@ -2480,7 +2482,7 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
   g->failing_since = approx_time() - 72*60*60;
   g->last_tried_to_connect = approx_time() - 72*60*60;
   state = 9999;
-  g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_ptr_op(g2, OP_EQ, g);
   tt_assert(g2);
   tt_uint_op(state, OP_EQ, GUARD_CIRC_STATE_USABLE_ON_COMPLETION);
@@ -2495,7 +2497,7 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
     guard->failing_since = approx_time() - 30;
   });
   state = 9999;
-  g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_assert(g2);
   tt_assert(!g2->is_primary);
   tt_int_op(g2->confirmed_idx, OP_EQ, -1);
@@ -2515,16 +2517,16 @@ test_entry_guard_select_for_circuit_no_confirmed(void *arg)
   });
 
   /* Let's try again and we should get the first primary guard again */
-  g = select_entry_guard_for_circuit(gs, NULL, &state);
+  g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_ptr_op(g, OP_EQ, smartlist_get(gs->primary_entry_guards, 0));
-  g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_ptr_op(g2, OP_EQ, g);
 
   /* But if we impose a restriction, we don't get the same guard */
   entry_guard_restriction_t rst;
   memset(&rst, 0, sizeof(rst));
   memcpy(rst.exclude_id, g->identity, DIGEST_LEN);
-  g2 = select_entry_guard_for_circuit(gs, &rst, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, &rst, &state);
   tt_ptr_op(g2, OP_NE, g);
 
  done:
@@ -2552,7 +2554,8 @@ test_entry_guard_select_for_circuit_confirmed(void *arg)
   unsigned state = 9999;
 
   // As above, this gives us a primary guard.
-  entry_guard_t *g = select_entry_guard_for_circuit(gs, NULL, &state);
+  entry_guard_t *g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC,
+                                                    NULL, &state);
   tt_assert(g);
   tt_assert(g->is_primary);
   tt_int_op(g->confirmed_idx, OP_EQ, 0);
@@ -2569,7 +2572,7 @@ test_entry_guard_select_for_circuit_confirmed(void *arg)
 
   // ... we should get a confirmed guard.
   state = 9999;
-  g = select_entry_guard_for_circuit(gs, NULL, &state);
+  g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_assert(g);
   tt_assert(! g->is_primary);
   tt_int_op(g->confirmed_idx, OP_EQ, smartlist_len(gs->primary_entry_guards));
@@ -2580,7 +2583,8 @@ test_entry_guard_select_for_circuit_confirmed(void *arg)
   // And if we try again, we should get a different confirmed guard, since
   // that one is pending.
   state = 9999;
-  entry_guard_t *g2 = select_entry_guard_for_circuit(gs, NULL, &state);
+  entry_guard_t *g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC,
+                                                     NULL, &state);
   tt_assert(g2);
   tt_assert(! g2->is_primary);
   tt_ptr_op(g2, OP_NE, g);
@@ -2597,7 +2601,7 @@ test_entry_guard_select_for_circuit_confirmed(void *arg)
   entry_guard_restriction_t rst;
   memset(&rst, 0, sizeof(rst));
   memcpy(rst.exclude_id, g->identity, DIGEST_LEN);
-  g2 = select_entry_guard_for_circuit(gs, &rst, &state);
+  g2 = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, &rst, &state);
   tt_ptr_op(g2, OP_NE, g);
   tt_int_op(g2->confirmed_idx, OP_EQ,
             smartlist_len(gs->primary_entry_guards)+3);
@@ -2607,12 +2611,12 @@ test_entry_guard_select_for_circuit_confirmed(void *arg)
   const int n_remaining_confirmed =
     N_CONFIRMED - 3 - smartlist_len(gs->primary_entry_guards);
   for (i = 0; i < n_remaining_confirmed; ++i) {
-    g = select_entry_guard_for_circuit(gs, NULL, &state);
+    g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
     tt_int_op(g->confirmed_idx, OP_GE, 0);
     tt_assert(g);
   }
   state = 9999;
-  g = select_entry_guard_for_circuit(gs, NULL, &state);
+  g = select_entry_guard_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &state);
   tt_assert(g);
   tt_assert(g->is_pending);
   tt_int_op(g->confirmed_idx, OP_EQ, -1);
@@ -2639,7 +2643,8 @@ test_entry_guard_select_for_circuit_highlevel_primary(void *arg)
    * Make sure that the pick-for-circuit API basically works.  We'll get
    * a primary guard, so it'll be usable on completion.
    */
-  int r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  int r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                       &node, &guard);
 
   tt_assert(r == 0);
   tt_assert(node);
@@ -2671,7 +2676,8 @@ test_entry_guard_select_for_circuit_highlevel_primary(void *arg)
   /* Try again. We'll also get a primary guard this time. (The same one,
      in fact.)  But this time, we'll say the connection has failed. */
   update_approx_time(start+35);
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard);
   tt_assert(r == 0);
   tt_assert(node);
   tt_assert(guard);
@@ -2706,7 +2712,8 @@ test_entry_guard_select_for_circuit_highlevel_primary(void *arg)
    * (still primary) guard.
    */
   update_approx_time(start+60);
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard);
   tt_assert(r == 0);
   tt_assert(node);
   tt_assert(guard);
@@ -2758,7 +2765,8 @@ test_entry_guard_select_for_circuit_highlevel_confirm_other(void *arg)
 
   /* Primary guards are down! */
   for (i = 0; i < N_PRIMARY; ++i) {
-    r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+    r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                     &node, &guard);
     tt_assert(node);
     tt_assert(guard);
     tt_assert(r == 0);
@@ -2771,7 +2779,8 @@ test_entry_guard_select_for_circuit_highlevel_confirm_other(void *arg)
 
   /* Next guard should be non-primary. */
   node = NULL;
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard);
   tt_assert(node);
   tt_assert(guard);
   tt_assert(r == 0);
@@ -2823,7 +2832,8 @@ test_entry_guard_select_for_circuit_highlevel_primary_retry(void *arg)
   /* Make primary guards confirmed (so they won't be superseded by a later
    * guard), then mark them down. */
   for (i = 0; i < N_PRIMARY; ++i) {
-    r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+    r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                     &node, &guard);
     tt_assert(node);
     tt_assert(guard);
     tt_assert(r == 0);
@@ -2839,7 +2849,8 @@ test_entry_guard_select_for_circuit_highlevel_primary_retry(void *arg)
   }
 
   /* Get another guard that we might try. */
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard);
   tt_assert(node);
   tt_assert(guard);
   tt_assert(r == 0);
@@ -2866,7 +2877,8 @@ test_entry_guard_select_for_circuit_highlevel_primary_retry(void *arg)
   });
 
   /* Have a circuit to a primary guard succeed. */
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard2);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard2);
   tt_assert(r == 0);
   tt_int_op(guard2->state, OP_EQ, GUARD_CIRC_STATE_USABLE_ON_COMPLETION);
   u = entry_guard_succeeded(&guard2);
@@ -2895,7 +2907,8 @@ test_entry_guard_select_and_cancel(void *arg)
   /* Once more, we mark all the primary guards down. */
   entry_guards_note_internet_connectivity(gs);
   for (i = 0; i < N_PRIMARY; ++i) {
-    r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+    r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                     &node, &guard);
     tt_int_op(guard->state, OP_EQ, GUARD_CIRC_STATE_USABLE_ON_COMPLETION);
     g = entry_guard_handle_get(guard->guard);
     tt_int_op(g->is_primary, OP_EQ, 1);
@@ -2910,7 +2923,8 @@ test_entry_guard_select_and_cancel(void *arg)
   tt_assert(entry_guards_all_primary_guards_are_down(gs));
 
   /* Now get another guard we could try... */
-  r = entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+  r = entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                                   &node, &guard);
   tt_assert(node);
   tt_assert(guard);
   tt_assert(r == 0);
@@ -2969,7 +2983,7 @@ upgrade_circuits_setup(const struct testcase_t *testcase)
   data->start = approx_time();
   entry_guards_note_internet_connectivity(gs);
   for (i = 0; i < N_PRIMARY; ++i) {
-    entry_guard_pick_for_circuit(gs, NULL, &node, &guard);
+    entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL, &node, &guard);
     g = entry_guard_handle_get(guard->guard);
     make_guard_confirmed(gs, g);
     entry_guard_failed(&guard);
@@ -2980,7 +2994,8 @@ upgrade_circuits_setup(const struct testcase_t *testcase)
   data->all_origin_circuits = smartlist_new();
 
   update_approx_time(data->start + 27);
-  entry_guard_pick_for_circuit(gs, NULL, &node, &data->guard1_state);
+  entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                               &node, &data->guard1_state);
   origin_circuit_t *circ;
   data->circ1 = circ = origin_circuit_new();
   circ->base_.purpose = CIRCUIT_PURPOSE_C_GENERAL;
@@ -2988,7 +3003,8 @@ upgrade_circuits_setup(const struct testcase_t *testcase)
   smartlist_add(data->all_origin_circuits, circ);
 
   update_approx_time(data->start + 30);
-  entry_guard_pick_for_circuit(gs, NULL, &node, &data->guard2_state);
+  entry_guard_pick_for_circuit(gs, GUARD_USAGE_TRAFFIC, NULL,
+                               &node, &data->guard2_state);
   data->circ2 = circ = origin_circuit_new();
   circ->base_.purpose = CIRCUIT_PURPOSE_C_GENERAL;
   circ->guard_state = data->guard2_state;