Write the easy parts of the public entryguard interface.

Here we add a little bit of state to origin circuits, and set up
the necessary functions for the circuit code to call in order to
find guards, use guards, and decide when circuits can be used.

There's also an incomplete function for the hard part of the
circuit-maintenance code, where we figure out whether any waiting
guards are ready to become usable.

(This patch finally uses the handle.c code to make safe handles to
entry_guard_t objects, so that we are allowed to free an
entry_guard_t without checking whether any origin_circuit_t is
holding a reference to it.)

1 files changed, 38 insertions, 0 deletions

diff --git a/src/or/entrynodes.h b/src/or/entrynodes.h
index 5501e624eb..5b3aa66a26 100644
--- a/src/or/entrynodes.h
+++ b/src/or/entrynodes.h
@@ -12,12 +12,18 @@
 #ifndef TOR_ENTRYNODES_H
 #define TOR_ENTRYNODES_H
 
+#include "handles.h"
+
 /* Forward declare for guard_selection_t; entrynodes.c has the real struct */
 typedef struct guard_selection_s guard_selection_t;
 
 /* Forward declare for entry_guard_t; the real declaration is private. */
 typedef struct entry_guard_t entry_guard_t;
 
+/* Forward declaration for circuit_guard_state_t; the real declaration is
+   private. */
+typedef struct circuit_guard_state_t circuit_guard_state_t;
+
 /* Information about a guard's pathbias status.
  * These fields are used in circpathbias.c to try to detect entry
  * nodes that are failing circuits at a suspicious frequency.
@@ -70,6 +76,8 @@ typedef struct guard_pathbias_t {
  * use a node_t, since we want to remember these even when we
  * don't have any directory info. */
 struct entry_guard_t {
+  HANDLE_ENTRY(entry_guard, entry_guard_t);
+
   char nickname[MAX_HEX_NICKNAME_LEN+1];
   char identity[DIGEST_LEN];
   ed25519_public_key_t ed_id;
@@ -259,6 +267,20 @@ struct guard_selection_s {
    */
   int should_add_entry_nodes;
 };
+
+struct entry_guard_handle_t;
+
+/**
+ * Per-circuit state to track whether we'll be able to use the circuit.
+ */
+struct circuit_guard_state_t {
+  /** Handle to the entry guard object for this circuit. */
+  struct entry_guard_handle_t *guard;
+  /** The time at which <b>state</b> last changed. */
+  time_t state_set_at;
+  /** One of GUARD_CIRC_STATE_* */
+  uint8_t state;
+};
 #endif
 
 #if 1
@@ -285,6 +307,19 @@ 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);
 
+void circuit_guard_state_free(circuit_guard_state_t *state);
+int entry_guard_pick_for_circuit(guard_selection_t *gs,
+                                 const node_t **chosen_node_out,
+                                 circuit_guard_state_t **guard_state_out);
+int entry_guard_succeeded(guard_selection_t *gs,
+                          circuit_guard_state_t **guard_state_p);
+int entry_guard_failed(guard_selection_t *gs,
+                       circuit_guard_state_t **guard_state_p);
+void entry_guards_update_all(guard_selection_t *gs);
+int entry_guards_upgrade_waiting_circuits(guard_selection_t *gs,
+                                          smartlist_t *all_circuits,
+                                          smartlist_t *newly_complete_out);
+
 /* Used by bridges.c only. */
 void add_bridge_as_entry_guard(guard_selection_t *gs,
                                const node_t *chosen);
@@ -350,6 +385,7 @@ int num_bridges_usable(void);
 /**@}*/
 
 // ---------- XXXX these functions and definitions are post-prop271.
+HANDLE_DECL(entry_guard, entry_guard_t, STATIC)
 STATIC guard_selection_t *guard_selection_new(void);
 STATIC void guard_selection_free(guard_selection_t *gs);
 STATIC entry_guard_t *get_sampled_guard_with_id(guard_selection_t *gs,
@@ -398,6 +434,8 @@ STATIC void sampled_guards_update_from_consensus(guard_selection_t *gs);
 /** State for a circuit that can (so far as the guard subsystem is
  * concerned) be used for actual traffic. */
 #define GUARD_CIRC_STATE_COMPLETE 4
+/** State for a circuit that is unusable, and will not become usable. */
+#define GUARD_CIRC_STATE_DEAD 5
 /**@}*/
 STATIC void entry_guards_note_guard_failure(guard_selection_t *gs,
                                             entry_guard_t *guard);