commit 3c12133038f5a9213b13beca50d91ddac2f9d7fb Author: Nick Mathewson nickm@torproject.org Date: Tue Nov 15 08:28:41 2016 -0500
Collect old guard algorithm parameters into one place --- src/or/entrynodes.c | 156 ++++++++++++++++++++++++++----------------------- src/or/networkstatus.h | 4 ++ 2 files changed, 87 insertions(+), 73 deletions(-)
diff --git a/src/or/entrynodes.c b/src/or/entrynodes.c index 95b3c5a..461d29f 100644 --- a/src/or/entrynodes.c +++ b/src/or/entrynodes.c @@ -81,6 +81,12 @@ static const node_t *choose_random_entry_impl(guard_selection_t *gs, int *n_options_out); static guard_selection_t * guard_selection_new(void);
+/** + * @name Constants for old (pre-prop271) guard selection algorithm. + */ + +/**@{*/ + /* Default number of entry guards in the case where the NumEntryGuards * consensus parameter is not set */ #define DEFAULT_N_GUARDS 1 @@ -88,6 +94,62 @@ static guard_selection_t * guard_selection_new(void); * consensus parameter is set). */ #define MIN_N_GUARDS 1 #define MAX_N_GUARDS 10 +/** Largest amount that we'll backdate chosen_on_date */ +#define CHOSEN_ON_DATE_SLOP (30*86400) +/** How long (in seconds) do we allow an entry guard to be nonfunctional, + * unlisted, excluded, or otherwise nonusable before we give up on it? */ +#define ENTRY_GUARD_REMOVE_AFTER (30*24*60*60) +/**}@*/ + +/** + * @name Networkstatus parameters for old (pre-prop271) guard selection + */ +/**@}*/ +/** Choose how many entry guards or directory guards we'll use. If + * <b>for_directory</b> is true, we return how many directory guards to + * use; else we return how many entry guards to use. */ +STATIC int +decide_num_guards(const or_options_t *options, int for_directory) +{ + if (for_directory) { + int answer; + if (options->NumDirectoryGuards != 0) + return options->NumDirectoryGuards; + answer = networkstatus_get_param(NULL, "NumDirectoryGuards", 0, 0, 10); + if (answer) /* non-zero means use the consensus value */ + return answer; + } + + if (options->NumEntryGuards) + return options->NumEntryGuards; + + /* Use the value from the consensus, or 3 if no guidance. */ + return networkstatus_get_param(NULL, "NumEntryGuards", DEFAULT_N_GUARDS, + MIN_N_GUARDS, MAX_N_GUARDS); +} + +/** Return 0 if we should apply guardfraction information found in the + * consensus. A specific consensus can be specified with the + * <b>ns</b> argument, if NULL the most recent one will be picked.*/ +int +should_apply_guardfraction(const networkstatus_t *ns) +{ + /* We need to check the corresponding torrc option and the consensus + * parameter if we need to. */ + const or_options_t *options = get_options(); + + /* If UseGuardFraction is 'auto' then check the same-named consensus + * parameter. If the consensus parameter is not present, default to + * "off". */ + if (options->UseGuardFraction == -1) { + return networkstatus_get_param(ns, "UseGuardFraction", + 0, /* default to "off" */ + 0, 1); + } + + return options->UseGuardFraction; +} +/**@}*/
/** Allocate a new guard_selection_t */
@@ -795,9 +857,6 @@ control_event_guard_deferred(void) #endif }
-/** Largest amount that we'll backdate chosen_on_date */ -#define CHOSEN_ON_DATE_SLOP (30*86400) - /** Add a new (preferably stable and fast) router to our chosen_entry_guards * list for the supplied guard selection. Return a pointer to the router if * we succeed, or NULL if we can't find any more suitable entries. @@ -903,27 +962,30 @@ add_bridge_as_entry_guard(guard_selection_t *gs, add_an_entry_guard(gs, chosen, 1, 1, 0, 0); }
-/** Choose how many entry guards or directory guards we'll use. If - * <b>for_directory</b> is true, we return how many directory guards to - * use; else we return how many entry guards to use. */ -STATIC int -decide_num_guards(const or_options_t *options, int for_directory) +/** + * Return the minimum lifetime of working entry guard, in seconds, + * as given in the consensus networkstatus. (Plus CHOSEN_ON_DATE_SLOP, + * so that we can do the chosen_on_date randomization while achieving the + * desired minimum lifetime.) + */ +static int32_t +guards_get_lifetime(void) { - if (for_directory) { - int answer; - if (options->NumDirectoryGuards != 0) - return options->NumDirectoryGuards; - answer = networkstatus_get_param(NULL, "NumDirectoryGuards", 0, 0, 10); - if (answer) /* non-zero means use the consensus value */ - return answer; - } + const or_options_t *options = get_options(); +#define DFLT_GUARD_LIFETIME (86400 * 60) /* Two months. */ +#define MIN_GUARD_LIFETIME (86400 * 30) /* One months. */ +#define MAX_GUARD_LIFETIME (86400 * 1826) /* Five years. */
- if (options->NumEntryGuards) - return options->NumEntryGuards; + if (options->GuardLifetime >= 1) { + return CLAMP(MIN_GUARD_LIFETIME, + options->GuardLifetime, + MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP; + }
- /* Use the value from the consensus, or 3 if no guidance. */ - return networkstatus_get_param(NULL, "NumEntryGuards", DEFAULT_N_GUARDS, - MIN_N_GUARDS, MAX_N_GUARDS); + return networkstatus_get_param(NULL, "GuardLifetime", + DFLT_GUARD_LIFETIME, + MIN_GUARD_LIFETIME, + MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP; }
/** If the use of entry guards is configured, choose more entry guards @@ -950,10 +1012,6 @@ pick_entry_guards(guard_selection_t *gs, entry_guards_changed_for_guard_selection(gs); }
-/** How long (in seconds) do we allow an entry guard to be nonfunctional, - * unlisted, excluded, or otherwise nonusable before we give up on it? */ -#define ENTRY_GUARD_REMOVE_AFTER (30*24*60*60) - /** Release all storage held by <b>e</b>. */ STATIC void entry_guard_free(entry_guard_t *e) @@ -966,32 +1024,6 @@ entry_guard_free(entry_guard_t *e) tor_free(e); }
-/** - * Return the minimum lifetime of working entry guard, in seconds, - * as given in the consensus networkstatus. (Plus CHOSEN_ON_DATE_SLOP, - * so that we can do the chosen_on_date randomization while achieving the - * desired minimum lifetime.) - */ -static int32_t -guards_get_lifetime(void) -{ - const or_options_t *options = get_options(); -#define DFLT_GUARD_LIFETIME (86400 * 60) /* Two months. */ -#define MIN_GUARD_LIFETIME (86400 * 30) /* One months. */ -#define MAX_GUARD_LIFETIME (86400 * 1826) /* Five years. */ - - if (options->GuardLifetime >= 1) { - return CLAMP(MIN_GUARD_LIFETIME, - options->GuardLifetime, - MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP; - } - - return networkstatus_get_param(NULL, "GuardLifetime", - DFLT_GUARD_LIFETIME, - MIN_GUARD_LIFETIME, - MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP; -} - /** Remove from a guard selection context any entry guard which was selected * by an unknown version of Tor, or which was selected by a version of Tor * that's known to select entry guards badly, or which was selected more 2 @@ -2221,28 +2253,6 @@ getinfo_helper_entry_guards(control_connection_t *conn, return 0; }
-/** Return 0 if we should apply guardfraction information found in the - * consensus. A specific consensus can be specified with the - * <b>ns</b> argument, if NULL the most recent one will be picked.*/ -int -should_apply_guardfraction(const networkstatus_t *ns) -{ - /* We need to check the corresponding torrc option and the consensus - * parameter if we need to. */ - const or_options_t *options = get_options(); - - /* If UseGuardFraction is 'auto' then check the same-named consensus - * parameter. If the consensus parameter is not present, default to - * "off". */ - if (options->UseGuardFraction == -1) { - return networkstatus_get_param(ns, "UseGuardFraction", - 0, /* default to "off" */ - 0, 1); - } - - return options->UseGuardFraction; -} - /* Given the original bandwidth of a guard and its guardfraction, * calculate how much bandwidth the guard should have as a guard and * as a non-guard. diff --git a/src/or/networkstatus.h b/src/or/networkstatus.h index 71f36b6..96f8347 100644 --- a/src/or/networkstatus.h +++ b/src/or/networkstatus.h @@ -111,6 +111,10 @@ int32_t networkstatus_get_param(const networkstatus_t *ns, const char *param_name, int32_t default_val, int32_t min_val, int32_t max_val); +int32_t networkstatus_get_param(const networkstatus_t *ns, + const char *param_name, + int32_t default_val, int32_t min_val, + int32_t max_val); int getinfo_helper_networkstatus(control_connection_t *conn, const char *question, char **answer, const char **errmsg);