diff options
Diffstat (limited to 'src/or/entrynodes.c')
| -rw-r--r-- | src/or/entrynodes.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/src/or/entrynodes.c b/src/or/entrynodes.c index e92c0c166d..5bb0a7317c 100644 --- a/src/or/entrynodes.c +++ b/src/or/entrynodes.c @@ -24,6 +24,7 @@ #include "entrynodes.h" #include "main.h" #include "microdesc.h" +#include "networkstatus.h" #include "nodelist.h" #include "policies.h" #include "router.h" @@ -332,6 +333,9 @@ 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 * entry_guards list. Return a pointer to the router if we succeed, * or NULL if we can't find any more suitable entries. @@ -445,6 +449,32 @@ 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 * 30) /* One month. */ +#define MIN_GUARD_LIFETIME (86400 * 60) /* Two 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 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 months ago. */ @@ -454,6 +484,7 @@ static int remove_obsolete_entry_guards(time_t now) { int changed = 0, i; + int32_t guard_lifetime = guards_get_lifetime(); for (i = 0; i < smartlist_len(entry_guards); ++i) { entry_guard_t *entry = smartlist_get(entry_guards, i); @@ -484,8 +515,8 @@ remove_obsolete_entry_guards(time_t now) } tor_free(tor_ver); } - if (!version_is_bad && entry->chosen_on_date + 3600*24*60 < now) { - /* It's been 2 months since the date listed in our state file. */ + if (!version_is_bad && entry->chosen_on_date + guard_lifetime < now) { + /* It's been too long since the date listed in our state file. */ msg = "was selected several months ago"; date_is_bad = 1; } |