entrynodes.h 24 KB

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  1. /* Copyright (c) 2001 Matej Pfajfar.
  2. * Copyright (c) 2001-2004, Roger Dingledine.
  3. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
  4. * Copyright (c) 2007-2017, The Tor Project, Inc. */
  5. /* See LICENSE for licensing information */
  6. /**
  7. * \file entrynodes.h
  8. * \brief Header file for circuitbuild.c.
  9. **/
  10. #ifndef TOR_ENTRYNODES_H
  11. #define TOR_ENTRYNODES_H
  12. #include "handles.h"
  13. /* Forward declare for guard_selection_t; entrynodes.c has the real struct */
  14. typedef struct guard_selection_s guard_selection_t;
  15. /* Forward declare for entry_guard_t; the real declaration is private. */
  16. typedef struct entry_guard_t entry_guard_t;
  17. /* Forward declaration for circuit_guard_state_t; the real declaration is
  18. private. */
  19. typedef struct circuit_guard_state_t circuit_guard_state_t;
  20. /* Forward declaration for entry_guard_restriction_t; the real declaration is
  21. private. */
  22. typedef struct entry_guard_restriction_t entry_guard_restriction_t;
  23. /* Information about a guard's pathbias status.
  24. * These fields are used in circpathbias.c to try to detect entry
  25. * nodes that are failing circuits at a suspicious frequency.
  26. */
  27. typedef struct guard_pathbias_t {
  28. unsigned int path_bias_noticed : 1; /**< Did we alert the user about path
  29. * bias for this node already? */
  30. unsigned int path_bias_warned : 1; /**< Did we alert the user about path bias
  31. * for this node already? */
  32. unsigned int path_bias_extreme : 1; /**< Did we alert the user about path
  33. * bias for this node already? */
  34. unsigned int path_bias_disabled : 1; /**< Have we disabled this node because
  35. * of path bias issues? */
  36. unsigned int path_bias_use_noticed : 1; /**< Did we alert the user about path
  37. * use bias for this node already? */
  38. unsigned int path_bias_use_extreme : 1; /**< Did we alert the user about path
  39. * use bias for this node already? */
  40. double circ_attempts; /**< Number of circuits this guard has "attempted" */
  41. double circ_successes; /**< Number of successfully built circuits using
  42. * this guard as first hop. */
  43. double successful_circuits_closed; /**< Number of circuits that carried
  44. * streams successfully. */
  45. double collapsed_circuits; /**< Number of fully built circuits that were
  46. * remotely closed before any streams were
  47. * attempted. */
  48. double unusable_circuits; /**< Number of circuits for which streams were
  49. * attempted, but none succeeded. */
  50. double timeouts; /**< Number of 'right-censored' circuit timeouts for this
  51. * guard. */
  52. double use_attempts; /**< Number of circuits we tried to use with streams */
  53. double use_successes; /**< Number of successfully used circuits using
  54. * this guard as first hop. */
  55. } guard_pathbias_t;
  56. #if defined(ENTRYNODES_PRIVATE)
  57. /**
  58. * @name values for entry_guard_t.is_reachable.
  59. *
  60. * See entry_guard_t.is_reachable for more information.
  61. */
  62. /**@{*/
  63. #define GUARD_REACHABLE_NO 0
  64. #define GUARD_REACHABLE_YES 1
  65. #define GUARD_REACHABLE_MAYBE 2
  66. /**@}*/
  67. /** An entry_guard_t represents our information about a chosen long-term
  68. * first hop, known as a "helper" node in the literature. We can't just
  69. * use a node_t, since we want to remember these even when we
  70. * don't have any directory info. */
  71. struct entry_guard_t {
  72. HANDLE_ENTRY(entry_guard, entry_guard_t);
  73. char nickname[MAX_HEX_NICKNAME_LEN+1];
  74. char identity[DIGEST_LEN];
  75. ed25519_public_key_t ed_id;
  76. /**
  77. * @name new guard selection algorithm fields.
  78. *
  79. * Only the new (prop271) algorithm uses these. For a more full
  80. * description of the algorithm, see the module documentation for
  81. * entrynodes.c
  82. */
  83. /**@{*/
  84. /* == Persistent fields, present for all sampled guards. */
  85. /** When was this guard added to the sample? */
  86. time_t sampled_on_date;
  87. /** Since what date has this guard been "unlisted"? A guard counts as
  88. * unlisted if we have a live consensus that does not include it, or
  89. * if we have a live consensus that does not include it as a usable
  90. * guard. This field is zero when the guard is listed. */
  91. time_t unlisted_since_date; // can be zero
  92. /** What version of Tor added this guard to the sample? */
  93. char *sampled_by_version;
  94. /** Is this guard listed right now? If this is set, then
  95. * unlisted_since_date should be set too. */
  96. unsigned currently_listed : 1;
  97. /* == Persistent fields, for confirmed guards only */
  98. /** When was this guard confirmed? (That is, when did we first use it
  99. * successfully and decide to keep it?) This field is zero if this is not a
  100. * confirmed guard. */
  101. time_t confirmed_on_date; /* 0 if not confirmed */
  102. /**
  103. * In what order was this guard confirmed? Guards with lower indices
  104. * appear earlier on the confirmed list. If the confirmed list is compacted,
  105. * this field corresponds to the index of this guard on the confirmed list.
  106. *
  107. * This field is set to -1 if this guard is not confirmed.
  108. */
  109. int confirmed_idx; /* -1 if not confirmed; otherwise the order that this
  110. * item should occur in the CONFIRMED_GUARDS ordered
  111. * list */
  112. /**
  113. * Which selection does this guard belong to?
  114. */
  115. char *selection_name;
  116. /** Bridges only: address of the bridge. */
  117. tor_addr_port_t *bridge_addr;
  118. /* ==== Non-persistent fields. */
  119. /* == These are used by sampled guards */
  120. /** When did we last decide to try using this guard for a circuit? 0 for
  121. * "not since we started up." */
  122. time_t last_tried_to_connect;
  123. /** How reachable do we consider this guard to be? One of
  124. * GUARD_REACHABLE_NO, GUARD_REACHABLE_YES, or GUARD_REACHABLE_MAYBE. */
  125. unsigned is_reachable : 2;
  126. /** Boolean: true iff this guard is pending. A pending guard is one
  127. * that we have an in-progress circuit through, and which we do not plan
  128. * to try again until it either succeeds or fails. Primary guards can
  129. * never be pending. */
  130. unsigned is_pending : 1;
  131. /** If true, don't write this guard to disk. (Used for bridges with unknown
  132. * identities) */
  133. unsigned is_persistent : 1;
  134. /** When did we get the earliest connection failure for this guard?
  135. * We clear this field on a successful connect. We do _not_ clear it
  136. * when we mark the guard as "MAYBE" reachable.
  137. */
  138. time_t failing_since;
  139. /* == Set inclusion flags. */
  140. /** If true, this guard is in the filtered set. The filtered set includes
  141. * all sampled guards that our configuration allows us to use. */
  142. unsigned is_filtered_guard : 1;
  143. /** If true, this guard is in the usable filtered set. The usable filtered
  144. * set includes all filtered guards that are not believed to be
  145. * unreachable. (That is, those for which is_reachable is not
  146. * GUARD_REACHABLE_NO) */
  147. unsigned is_usable_filtered_guard : 1;
  148. unsigned is_primary:1;
  149. /** This string holds any fields that we are maintaining because
  150. * we saw them in the state, even if we don't understand them. */
  151. char *extra_state_fields;
  152. /** Backpointer to the guard selection that this guard belongs to.
  153. * The entry_guard_t must never outlive its guard_selection. */
  154. guard_selection_t *in_selection;
  155. /**@}*/
  156. /** Path bias information for this guard. */
  157. guard_pathbias_t pb;
  158. };
  159. /**
  160. * Possible rules for a guard selection to follow
  161. */
  162. typedef enum guard_selection_type_t {
  163. /** Infer the type of this selection from its name. */
  164. GS_TYPE_INFER=0,
  165. /** Use the normal guard selection algorithm, taking our sample from the
  166. * complete list of guards in the consensus. */
  167. GS_TYPE_NORMAL=1,
  168. /** Use the normal guard selection algorithm, taking our sample from the
  169. * configured bridges, and allowing it to grow as large as all the configured
  170. * bridges */
  171. GS_TYPE_BRIDGE,
  172. /** Use the normal guard selection algorithm, taking our sample from the
  173. * set of filtered nodes. */
  174. GS_TYPE_RESTRICTED,
  175. } guard_selection_type_t;
  176. /**
  177. * All of the the context for guard selection on a particular client.
  178. *
  179. * We maintain multiple guard selection contexts for a client, depending
  180. * aspects on its current configuration -- whether an extremely
  181. * restrictive EntryNodes is used, whether UseBridges is enabled, and so
  182. * on.)
  183. *
  184. * See the module documentation for entrynodes.c for more information
  185. * about guard selection algorithms.
  186. */
  187. struct guard_selection_s {
  188. /**
  189. * The name for this guard-selection object. (Must not contain spaces).
  190. */
  191. char *name;
  192. /**
  193. * What rules does this guard-selection object follow?
  194. */
  195. guard_selection_type_t type;
  196. /**
  197. * A value of 1 means that primary_entry_guards is up-to-date; 0
  198. * means we need to recalculate it before using primary_entry_guards
  199. * or the is_primary flag on any guard.
  200. */
  201. int primary_guards_up_to_date;
  202. /**
  203. * A list of the sampled entry guards, as entry_guard_t structures.
  204. * Not in any particular order. When we 'sample' a guard, we are
  205. * noting it as a possible guard to pick in the future. The use of
  206. * sampling here prevents us from being forced by an attacker to try
  207. * every guard on the network. This list is persistent.
  208. */
  209. smartlist_t *sampled_entry_guards;
  210. /**
  211. * Ordered list (from highest to lowest priority) of guards that we
  212. * have successfully contacted and decided to use. Every member of
  213. * this list is a member of sampled_entry_guards. Every member should
  214. * have confirmed_on_date set, and have confirmed_idx greater than
  215. * any earlier member of the list.
  216. *
  217. * This list is persistent. It is a subset of the elements in
  218. * sampled_entry_guards, and its pointers point to elements of
  219. * sampled_entry_guards.
  220. */
  221. smartlist_t *confirmed_entry_guards;
  222. /**
  223. * Ordered list (from highest to lowest priority) of guards that we
  224. * are willing to use the most happily. These guards may or may not
  225. * yet be confirmed yet. If we can use one of these guards, we are
  226. * probably not on a network that is trying to restrict our guard
  227. * choices.
  228. *
  229. * This list is a subset of the elements in
  230. * sampled_entry_guards, and its pointers point to elements of
  231. * sampled_entry_guards.
  232. */
  233. smartlist_t *primary_entry_guards;
  234. /** When did we last successfully build a circuit or use a circuit? */
  235. time_t last_time_on_internet;
  236. /** What confirmed_idx value should the next-added member of
  237. * confirmed_entry_guards receive? */
  238. int next_confirmed_idx;
  239. };
  240. struct entry_guard_handle_t;
  241. /**
  242. * A restriction to remember which entry guards are off-limits for a given
  243. * circuit.
  244. *
  245. * Right now, we only use restrictions to block a single guard from being
  246. * selected; this mechanism is designed to be more extensible in the future,
  247. * however.
  248. *
  249. * Note: This mechanism is NOT for recording which guards are never to be
  250. * used: only which guards cannot be used on <em>one particular circuit</em>.
  251. */
  252. struct entry_guard_restriction_t {
  253. /**
  254. * The guard's RSA identity digest must not equal this.
  255. */
  256. uint8_t exclude_id[DIGEST_LEN];
  257. };
  258. /**
  259. * Per-circuit state to track whether we'll be able to use the circuit.
  260. */
  261. struct circuit_guard_state_t {
  262. /** Handle to the entry guard object for this circuit. */
  263. struct entry_guard_handle_t *guard;
  264. /** The time at which <b>state</b> last changed. */
  265. time_t state_set_at;
  266. /** One of GUARD_CIRC_STATE_* */
  267. uint8_t state;
  268. /**
  269. * A set of restrictions that were placed on this guard when we selected it
  270. * for this particular circuit. We need to remember the restrictions here,
  271. * since any guard that breaks these restrictions will not block this
  272. * circuit from becoming COMPLETE.
  273. */
  274. entry_guard_restriction_t *restrictions;
  275. };
  276. #endif
  277. /* Common entry points for old and new guard code */
  278. int guards_update_all(void);
  279. const node_t *guards_choose_guard(cpath_build_state_t *state,
  280. circuit_guard_state_t **guard_state_out);
  281. const node_t *guards_choose_dirguard(circuit_guard_state_t **guard_state_out);
  282. #if 1
  283. /* XXXX NM I would prefer that all of this stuff be private to
  284. * entrynodes.c. */
  285. entry_guard_t *entry_guard_get_by_id_digest_for_guard_selection(
  286. guard_selection_t *gs, const char *digest);
  287. entry_guard_t *entry_guard_get_by_id_digest(const char *digest);
  288. circuit_guard_state_t *
  289. get_guard_state_for_bridge_desc_fetch(const char *digest);
  290. void entry_guards_changed_for_guard_selection(guard_selection_t *gs);
  291. void entry_guards_changed(void);
  292. guard_selection_t * get_guard_selection_info(void);
  293. int num_live_entry_guards_for_guard_selection(
  294. guard_selection_t *gs,
  295. int for_directory);
  296. int num_live_entry_guards(int for_directory);
  297. #endif
  298. const node_t *entry_guard_find_node(const entry_guard_t *guard);
  299. const char *entry_guard_get_rsa_id_digest(const entry_guard_t *guard);
  300. const char *entry_guard_describe(const entry_guard_t *guard);
  301. guard_pathbias_t *entry_guard_get_pathbias_state(entry_guard_t *guard);
  302. /** Enum to specify how we're going to use a given guard, when we're picking
  303. * one for immediate use. */
  304. typedef enum {
  305. GUARD_USAGE_TRAFFIC = 0,
  306. GUARD_USAGE_DIRGUARD = 1
  307. } guard_usage_t;
  308. void circuit_guard_state_free(circuit_guard_state_t *state);
  309. int entry_guard_pick_for_circuit(guard_selection_t *gs,
  310. guard_usage_t usage,
  311. entry_guard_restriction_t *rst,
  312. const node_t **chosen_node_out,
  313. circuit_guard_state_t **guard_state_out);
  314. /* We just connected to an entry guard. What should we do with the circuit? */
  315. typedef enum {
  316. GUARD_USABLE_NEVER = -1, /* Never use the circuit */
  317. GUARD_MAYBE_USABLE_LATER = 0, /* Keep it. We might use it in the future */
  318. GUARD_USABLE_NOW = 1, /* Use it right now */
  319. } guard_usable_t;
  320. guard_usable_t entry_guard_succeeded(circuit_guard_state_t **guard_state_p);
  321. void entry_guard_failed(circuit_guard_state_t **guard_state_p);
  322. void entry_guard_cancel(circuit_guard_state_t **guard_state_p);
  323. void entry_guard_chan_failed(channel_t *chan);
  324. int entry_guards_update_all(guard_selection_t *gs);
  325. int entry_guards_upgrade_waiting_circuits(guard_selection_t *gs,
  326. const smartlist_t *all_circuits,
  327. smartlist_t *newly_complete_out);
  328. int entry_guard_state_should_expire(circuit_guard_state_t *guard_state);
  329. void entry_guards_note_internet_connectivity(guard_selection_t *gs);
  330. int update_guard_selection_choice(const or_options_t *options);
  331. /* Used by bridges.c only. */
  332. int num_bridges_usable(void);
  333. #ifdef ENTRYNODES_PRIVATE
  334. /**
  335. * @name Default values for the parameters for the new (prop271) entry guard
  336. * algorithm.
  337. */
  338. /**@{*/
  339. /**
  340. * We never let our sampled guard set grow larger than this percentage
  341. * of the guards on the network.
  342. */
  343. #define DFLT_MAX_SAMPLE_THRESHOLD_PERCENT 20
  344. /**
  345. * We never let our sampled guard set grow larger than this number of
  346. * guards.
  347. */
  348. #define DFLT_MAX_SAMPLE_SIZE 60
  349. /**
  350. * We always try to make our sample contain at least this many guards.
  351. */
  352. #define DFLT_MIN_FILTERED_SAMPLE_SIZE 20
  353. /**
  354. * If a guard is unlisted for this many days in a row, we remove it.
  355. */
  356. #define DFLT_REMOVE_UNLISTED_GUARDS_AFTER_DAYS 20
  357. /**
  358. * We remove unconfirmed guards from the sample after this many days,
  359. * regardless of whether they are listed or unlisted.
  360. */
  361. #define DFLT_GUARD_LIFETIME_DAYS 120
  362. /**
  363. * We remove confirmed guards from the sample if they were sampled
  364. * GUARD_LIFETIME_DAYS ago and confirmed this many days ago.
  365. */
  366. #define DFLT_GUARD_CONFIRMED_MIN_LIFETIME_DAYS 60
  367. /**
  368. * How many guards do we try to keep on our primary guard list?
  369. */
  370. #define DFLT_N_PRIMARY_GUARDS 3
  371. /**
  372. * Of the live guards on the primary guard list, how many do we consider when
  373. * choosing a guard to use?
  374. */
  375. #define DFLT_N_PRIMARY_GUARDS_TO_USE 1
  376. /**
  377. * As DFLT_N_PRIMARY_GUARDS, but for choosing which directory guard to use.
  378. */
  379. #define DFLT_N_PRIMARY_DIR_GUARDS_TO_USE 3
  380. /**
  381. * If we haven't successfully built or used a circuit in this long, then
  382. * consider that the internet is probably down.
  383. */
  384. #define DFLT_INTERNET_LIKELY_DOWN_INTERVAL (10*60)
  385. /**
  386. * If we're trying to connect to a nonprimary guard for at least this
  387. * many seconds, and we haven't gotten the connection to work, we will treat
  388. * lower-priority guards as usable.
  389. */
  390. #define DFLT_NONPRIMARY_GUARD_CONNECT_TIMEOUT 15
  391. /**
  392. * If a circuit has been sitting around in 'waiting for better guard' state
  393. * for at least this long, we'll expire it.
  394. */
  395. #define DFLT_NONPRIMARY_GUARD_IDLE_TIMEOUT (10*60)
  396. /**
  397. * If our configuration retains fewer than this fraction of guards from the
  398. * torrc, we are in a restricted setting.
  399. */
  400. #define DFLT_MEANINGFUL_RESTRICTION_PERCENT 20
  401. /**
  402. * If our configuration retains fewer than this fraction of guards from the
  403. * torrc, we are in an extremely restricted setting, and should warn.
  404. */
  405. #define DFLT_EXTREME_RESTRICTION_PERCENT 1
  406. /**@}*/
  407. STATIC double get_max_sample_threshold(void);
  408. STATIC int get_max_sample_size_absolute(void);
  409. STATIC int get_min_filtered_sample_size(void);
  410. STATIC int get_remove_unlisted_guards_after_days(void);
  411. STATIC int get_guard_lifetime(void);
  412. STATIC int get_guard_confirmed_min_lifetime(void);
  413. STATIC int get_n_primary_guards(void);
  414. STATIC int get_n_primary_guards_to_use(guard_usage_t usage);
  415. STATIC int get_internet_likely_down_interval(void);
  416. STATIC int get_nonprimary_guard_connect_timeout(void);
  417. STATIC int get_nonprimary_guard_idle_timeout(void);
  418. STATIC double get_meaningful_restriction_threshold(void);
  419. STATIC double get_extreme_restriction_threshold(void);
  420. HANDLE_DECL(entry_guard, entry_guard_t, STATIC)
  421. STATIC guard_selection_type_t guard_selection_infer_type(
  422. guard_selection_type_t type_in,
  423. const char *name);
  424. STATIC guard_selection_t *guard_selection_new(const char *name,
  425. guard_selection_type_t type);
  426. STATIC guard_selection_t *get_guard_selection_by_name(
  427. const char *name, guard_selection_type_t type, int create_if_absent);
  428. STATIC void guard_selection_free(guard_selection_t *gs);
  429. MOCK_DECL(STATIC int, entry_guard_is_listed,
  430. (guard_selection_t *gs, const entry_guard_t *guard));
  431. STATIC const char *choose_guard_selection(const or_options_t *options,
  432. const networkstatus_t *ns,
  433. const guard_selection_t *old_selection,
  434. guard_selection_type_t *type_out);
  435. STATIC entry_guard_t *get_sampled_guard_with_id(guard_selection_t *gs,
  436. const uint8_t *rsa_id);
  437. MOCK_DECL(STATIC time_t, randomize_time, (time_t now, time_t max_backdate));
  438. STATIC entry_guard_t *entry_guard_add_to_sample(guard_selection_t *gs,
  439. const node_t *node);
  440. STATIC entry_guard_t *entry_guards_expand_sample(guard_selection_t *gs);
  441. STATIC char *entry_guard_encode_for_state(entry_guard_t *guard);
  442. STATIC entry_guard_t *entry_guard_parse_from_state(const char *s);
  443. STATIC void entry_guard_free(entry_guard_t *e);
  444. STATIC void entry_guards_update_filtered_sets(guard_selection_t *gs);
  445. STATIC int entry_guards_all_primary_guards_are_down(guard_selection_t *gs);
  446. /**
  447. * @name Flags for sample_reachable_filtered_entry_guards()
  448. */
  449. /**@{*/
  450. #define SAMPLE_EXCLUDE_CONFIRMED (1u<<0)
  451. #define SAMPLE_EXCLUDE_PRIMARY (1u<<1)
  452. #define SAMPLE_EXCLUDE_PENDING (1u<<2)
  453. #define SAMPLE_NO_UPDATE_PRIMARY (1u<<3)
  454. #define SAMPLE_EXCLUDE_NO_DESCRIPTOR (1u<<4)
  455. /**@}*/
  456. STATIC entry_guard_t *sample_reachable_filtered_entry_guards(
  457. guard_selection_t *gs,
  458. const entry_guard_restriction_t *rst,
  459. unsigned flags);
  460. STATIC void entry_guard_consider_retry(entry_guard_t *guard);
  461. STATIC void make_guard_confirmed(guard_selection_t *gs, entry_guard_t *guard);
  462. STATIC void entry_guards_update_confirmed(guard_selection_t *gs);
  463. STATIC void entry_guards_update_primary(guard_selection_t *gs);
  464. STATIC int num_reachable_filtered_guards(guard_selection_t *gs,
  465. const entry_guard_restriction_t *rst);
  466. STATIC void sampled_guards_update_from_consensus(guard_selection_t *gs);
  467. /**
  468. * @name Possible guard-states for a circuit.
  469. */
  470. /**@{*/
  471. /** State for a circuit that can (so far as the guard subsystem is
  472. * concerned) be used for actual traffic as soon as it is successfully
  473. * opened. */
  474. #define GUARD_CIRC_STATE_USABLE_ON_COMPLETION 1
  475. /** State for an non-open circuit that we shouldn't use for actual
  476. * traffic, when it completes, unless other circuits to preferable
  477. * guards fail. */
  478. #define GUARD_CIRC_STATE_USABLE_IF_NO_BETTER_GUARD 2
  479. /** State for an open circuit that we shouldn't use for actual traffic
  480. * unless other circuits to preferable guards fail. */
  481. #define GUARD_CIRC_STATE_WAITING_FOR_BETTER_GUARD 3
  482. /** State for a circuit that can (so far as the guard subsystem is
  483. * concerned) be used for actual traffic. */
  484. #define GUARD_CIRC_STATE_COMPLETE 4
  485. /** State for a circuit that is unusable, and will not become usable. */
  486. #define GUARD_CIRC_STATE_DEAD 5
  487. /**@}*/
  488. STATIC void entry_guards_note_guard_failure(guard_selection_t *gs,
  489. entry_guard_t *guard);
  490. STATIC entry_guard_t *select_entry_guard_for_circuit(guard_selection_t *gs,
  491. guard_usage_t usage,
  492. const entry_guard_restriction_t *rst,
  493. unsigned *state_out);
  494. STATIC void mark_primary_guards_maybe_reachable(guard_selection_t *gs);
  495. STATIC unsigned entry_guards_note_guard_success(guard_selection_t *gs,
  496. entry_guard_t *guard,
  497. unsigned old_state);
  498. STATIC int entry_guard_has_higher_priority(entry_guard_t *a, entry_guard_t *b);
  499. STATIC char *getinfo_helper_format_single_entry_guard(const entry_guard_t *e);
  500. #endif
  501. void remove_all_entry_guards_for_guard_selection(guard_selection_t *gs);
  502. void remove_all_entry_guards(void);
  503. struct bridge_info_t;
  504. void entry_guard_learned_bridge_identity(const tor_addr_port_t *addrport,
  505. const uint8_t *rsa_id_digest);
  506. int entry_list_is_constrained(const or_options_t *options);
  507. int guards_retry_optimistic(const or_options_t *options);
  508. int entry_guards_parse_state_for_guard_selection(
  509. guard_selection_t *gs, or_state_t *state, int set, char **msg);
  510. int entry_guards_parse_state(or_state_t *state, int set, char **msg);
  511. void entry_guards_update_state(or_state_t *state);
  512. int getinfo_helper_entry_guards(control_connection_t *conn,
  513. const char *question, char **answer,
  514. const char **errmsg);
  515. int entries_known_but_down(const or_options_t *options);
  516. void entries_retry_all(const or_options_t *options);
  517. int guard_selection_have_enough_dir_info_to_build_circuits(
  518. guard_selection_t *gs);
  519. int entry_guards_have_enough_dir_info_to_build_circuits(void);
  520. void entry_guards_free_all(void);
  521. double pathbias_get_close_success_count(entry_guard_t *guard);
  522. double pathbias_get_use_success_count(entry_guard_t *guard);
  523. /** Contains the bandwidth of a relay as a guard and as a non-guard
  524. * after the guardfraction has been considered. */
  525. typedef struct guardfraction_bandwidth_t {
  526. /** Bandwidth as a guard after guardfraction has been considered. */
  527. int guard_bw;
  528. /** Bandwidth as a non-guard after guardfraction has been considered. */
  529. int non_guard_bw;
  530. } guardfraction_bandwidth_t;
  531. int should_apply_guardfraction(const networkstatus_t *ns);
  532. void
  533. guard_get_guardfraction_bandwidth(guardfraction_bandwidth_t *guardfraction_bw,
  534. int orig_bandwidth,
  535. uint32_t guardfraction_percentage);
  536. #endif