/* Copyright (c) 2001 Matej Pfajfar. * Copyright (c) 2001-2004, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. * Copyright (c) 2007-2016, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** * \file entrynodes.c * \brief Code to manage our fixed first nodes for various functions. * * Entry nodes can be guards (for general use) or bridges (for censorship * circumvention). **/ #define ENTRYNODES_PRIVATE #include "or.h" #include "circpathbias.h" #include "circuitbuild.h" #include "circuitstats.h" #include "config.h" #include "confparse.h" #include "connection.h" #include "connection_or.h" #include "control.h" #include "directory.h" #include "entrynodes.h" #include "main.h" #include "microdesc.h" #include "networkstatus.h" #include "nodelist.h" #include "policies.h" #include "router.h" #include "routerlist.h" #include "routerparse.h" #include "routerset.h" #include "transports.h" #include "statefile.h" /** Information about a configured bridge. Currently this just matches the * ones in the torrc file, but one day we may be able to learn about new * bridges on our own, and remember them in the state file. */ typedef struct { /** Address of the bridge. */ tor_addr_t addr; /** TLS port for the bridge. */ uint16_t port; /** Boolean: We are re-parsing our bridge list, and we are going to remove * this one if we don't find it in the list of configured bridges. */ unsigned marked_for_removal : 1; /** Expected identity digest, or all zero bytes if we don't know what the * digest should be. */ char identity[DIGEST_LEN]; /** Name of pluggable transport protocol taken from its config line. */ char *transport_name; /** When should we next try to fetch a descriptor for this bridge? */ download_status_t fetch_status; /** A smartlist of k=v values to be passed to the SOCKS proxy, if transports are used for this bridge. */ smartlist_t *socks_args; } bridge_info_t; /** A list of our chosen entry guards. */ static smartlist_t *entry_guards = NULL; /** A value of 1 means that the entry_guards list has changed * and those changes need to be flushed to disk. */ static int entry_guards_dirty = 0; static void bridge_free(bridge_info_t *bridge); static const node_t *choose_random_entry_impl(cpath_build_state_t *state, int for_directory, dirinfo_type_t dirtype, int *n_options_out); static int num_bridges_usable(void); /* Default number of entry guards in the case where the NumEntryGuards * consensus parameter is not set */ #define DEFAULT_N_GUARDS 1 /* Minimum and maximum number of entry guards (in case the NumEntryGuards * consensus parameter is set). */ #define MIN_N_GUARDS 1 #define MAX_N_GUARDS 10 /** Return the list of entry guards, creating it if necessary. */ const smartlist_t * get_entry_guards(void) { if (! entry_guards) entry_guards = smartlist_new(); return entry_guards; } /** Check whether the entry guard e is usable, given the directory * authorities' opinion about the router (stored in ri) and the user's * configuration (in options). Set e->bad_since * accordingly. Return true iff the entry guard's status changes. * * If it's not usable, set *reason to a static string explaining why. */ static int entry_guard_set_status(entry_guard_t *e, const node_t *node, time_t now, const or_options_t *options, const char **reason) { char buf[HEX_DIGEST_LEN+1]; int changed = 0; *reason = NULL; /* Do we want to mark this guard as bad? */ if (!node) *reason = "unlisted"; else if (!node->is_running) *reason = "down"; else if (options->UseBridges && (!node->ri || node->ri->purpose != ROUTER_PURPOSE_BRIDGE)) *reason = "not a bridge"; else if (options->UseBridges && !node_is_a_configured_bridge(node)) *reason = "not a configured bridge"; else if (!options->UseBridges && !node->is_possible_guard && !routerset_contains_node(options->EntryNodes,node)) *reason = "not recommended as a guard"; else if (routerset_contains_node(options->ExcludeNodes, node)) *reason = "excluded"; /* We only care about OR connection connectivity for entry guards. */ else if (!fascist_firewall_allows_node(node, FIREWALL_OR_CONNECTION, 0)) *reason = "unreachable by config"; else if (e->path_bias_disabled) *reason = "path-biased"; if (*reason && ! e->bad_since) { /* Router is newly bad. */ base16_encode(buf, sizeof(buf), e->identity, DIGEST_LEN); log_info(LD_CIRC, "Entry guard %s (%s) is %s: marking as unusable.", e->nickname, buf, *reason); e->bad_since = now; control_event_guard(e->nickname, e->identity, "BAD"); changed = 1; } else if (!*reason && e->bad_since) { /* There's nothing wrong with the router any more. */ base16_encode(buf, sizeof(buf), e->identity, DIGEST_LEN); log_info(LD_CIRC, "Entry guard %s (%s) is no longer unusable: " "marking as ok.", e->nickname, buf); e->bad_since = 0; control_event_guard(e->nickname, e->identity, "GOOD"); changed = 1; } if (node) { int is_dir = node_is_dir(node); if (options->UseBridges && node_is_a_configured_bridge(node)) is_dir = 1; if (e->is_dir_cache != is_dir) { e->is_dir_cache = is_dir; changed = 1; } } return changed; } /** Return true iff enough time has passed since we last tried to connect * to the unreachable guard e that we're willing to try again. */ STATIC int entry_is_time_to_retry(const entry_guard_t *e, time_t now) { struct guard_retry_period_s { time_t period_duration; time_t interval_during_period; }; struct guard_retry_period_s periods[] = { { 6*60*60, 60*60 }, /* For first 6 hrs., retry hourly; */ { 3*24*60*60, 4*60*60 }, /* Then retry every 4 hrs. until the 3-day mark; */ { 7*24*60*60, 18*60*60 }, /* After 3 days, retry every 18 hours until 1 week mark. */ { TIME_MAX, 36*60*60 } /* After 1 week, retry every 36 hours. */ }; time_t ith_deadline_for_retry; time_t unreachable_for; unsigned i; if (e->last_attempted < e->unreachable_since) return 1; unreachable_for = now - e->unreachable_since; for (i = 0; i < ARRAY_LENGTH(periods); i++) { if (unreachable_for <= periods[i].period_duration) { ith_deadline_for_retry = e->last_attempted + periods[i].interval_during_period; return (now > ith_deadline_for_retry); } } return 0; } /** Return the node corresponding to e, if e is * working well enough that we are willing to use it as an entry * right now. (Else return NULL.) In particular, it must be * - Listed as either up or never yet contacted; * - Present in the routerlist; * - Listed as 'stable' or 'fast' by the current dirserver consensus, * if demanded by need_uptime or need_capacity * (unless it's a configured EntryNode); * - Allowed by our current ReachableORAddresses config option; and * - Currently thought to be reachable by us (unless assume_reachable * is true). * * If the answer is no, set *msg to an explanation of why. * * If need_descriptor is true, only return the node if we currently have * a descriptor (routerinfo or microdesc) for it. */ STATIC const node_t * entry_is_live(const entry_guard_t *e, entry_is_live_flags_t flags, const char **msg) { const node_t *node; const or_options_t *options = get_options(); int need_uptime = (flags & ENTRY_NEED_UPTIME) != 0; int need_capacity = (flags & ENTRY_NEED_CAPACITY) != 0; const int assume_reachable = (flags & ENTRY_ASSUME_REACHABLE) != 0; const int need_descriptor = (flags & ENTRY_NEED_DESCRIPTOR) != 0; tor_assert(msg); if (e->path_bias_disabled) { *msg = "path-biased"; return NULL; } if (e->bad_since) { *msg = "bad"; return NULL; } /* no good if it's unreachable, unless assume_unreachable or can_retry. */ if (!assume_reachable && !e->can_retry && e->unreachable_since && !entry_is_time_to_retry(e, time(NULL))) { *msg = "unreachable"; return NULL; } node = node_get_by_id(e->identity); if (!node) { *msg = "no node info"; return NULL; } if (need_descriptor && !node_has_descriptor(node)) { *msg = "no descriptor"; return NULL; } if (get_options()->UseBridges) { if (node_get_purpose(node) != ROUTER_PURPOSE_BRIDGE) { *msg = "not a bridge"; return NULL; } if (!node_is_a_configured_bridge(node)) { *msg = "not a configured bridge"; return NULL; } } else { /* !get_options()->UseBridges */ if (node_get_purpose(node) != ROUTER_PURPOSE_GENERAL) { *msg = "not general-purpose"; return NULL; } } if (routerset_contains_node(options->EntryNodes, node)) { /* they asked for it, they get it */ need_uptime = need_capacity = 0; } if (node_is_unreliable(node, need_uptime, need_capacity, 0)) { *msg = "not fast/stable"; return NULL; } if (!fascist_firewall_allows_node(node, FIREWALL_OR_CONNECTION, 0)) { *msg = "unreachable by config"; return NULL; } return node; } /** Return the number of entry guards that we think are usable. */ int num_live_entry_guards(int for_directory) { int n = 0; const char *msg; /* Set the entry node attributes we are interested in. */ entry_is_live_flags_t entry_flags = ENTRY_NEED_CAPACITY; if (!for_directory) { entry_flags |= ENTRY_NEED_DESCRIPTOR; } if (! entry_guards) return 0; SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) { if (for_directory && !entry->is_dir_cache) continue; if (entry_is_live(entry, entry_flags, &msg)) ++n; } SMARTLIST_FOREACH_END(entry); return n; } /** If digest matches the identity of any node in the * entry_guards list, return that node. Else return NULL. */ entry_guard_t * entry_guard_get_by_id_digest(const char *digest) { SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry, if (tor_memeq(digest, entry->identity, DIGEST_LEN)) return entry; ); return NULL; } /** Dump a description of our list of entry guards to the log at level * severity. */ static void log_entry_guards(int severity) { smartlist_t *elements = smartlist_new(); char *s; SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { const char *msg = NULL; if (entry_is_live(e, ENTRY_NEED_CAPACITY, &msg)) smartlist_add_asprintf(elements, "%s [%s] (up %s)", e->nickname, hex_str(e->identity, DIGEST_LEN), e->made_contact ? "made-contact" : "never-contacted"); else smartlist_add_asprintf(elements, "%s [%s] (%s, %s)", e->nickname, hex_str(e->identity, DIGEST_LEN), msg, e->made_contact ? "made-contact" : "never-contacted"); } SMARTLIST_FOREACH_END(e); s = smartlist_join_strings(elements, ",", 0, NULL); SMARTLIST_FOREACH(elements, char*, cp, tor_free(cp)); smartlist_free(elements); log_fn(severity,LD_CIRC,"%s",s); tor_free(s); } /** Called when one or more guards that we would previously have used for some * purpose are no longer in use because a higher-priority guard has become * usable again. */ static void control_event_guard_deferred(void) { /* XXXX We don't actually have a good way to figure out _how many_ entries * are live for some purpose. We need an entry_is_even_slightly_live() * function for this to work right. NumEntryGuards isn't reliable: if we * need guards with weird properties, we can have more than that number * live. **/ #if 0 int n = 0; const char *msg; const or_options_t *options = get_options(); if (!entry_guards) return; SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry, { if (entry_is_live(entry, 0, 1, 0, &msg)) { if (n++ == options->NumEntryGuards) { control_event_guard(entry->nickname, entry->identity, "DEFERRED"); return; } } }); #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. * * If chosen is defined, use that one, and if it's not * already in our entry_guards list, put it at the *beginning*. * Else, put the one we pick at the end of the list. */ STATIC const node_t * add_an_entry_guard(const node_t *chosen, int reset_status, int prepend, int for_discovery, int for_directory) { const node_t *node; entry_guard_t *entry; if (chosen) { node = chosen; entry = entry_guard_get_by_id_digest(node->identity); if (entry) { if (reset_status) { entry->bad_since = 0; entry->can_retry = 1; } entry->is_dir_cache = node_is_dir(node); if (get_options()->UseBridges && node_is_a_configured_bridge(node)) entry->is_dir_cache = 1; return NULL; } } else if (!for_directory) { node = choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL); if (!node) return NULL; } else { const routerstatus_t *rs; rs = router_pick_directory_server(MICRODESC_DIRINFO|V3_DIRINFO, PDS_FOR_GUARD); if (!rs) return NULL; node = node_get_by_id(rs->identity_digest); if (!node) return NULL; } if (node->using_as_guard) return NULL; if (entry_guard_get_by_id_digest(node->identity) != NULL) { log_info(LD_CIRC, "I was about to add a duplicate entry guard."); /* This can happen if we choose a guard, then the node goes away, then * comes back. */ ((node_t*) node)->using_as_guard = 1; return NULL; } entry = tor_malloc_zero(sizeof(entry_guard_t)); log_info(LD_CIRC, "Chose %s as new entry guard.", node_describe(node)); strlcpy(entry->nickname, node_get_nickname(node), sizeof(entry->nickname)); memcpy(entry->identity, node->identity, DIGEST_LEN); entry->is_dir_cache = node_is_dir(node); if (get_options()->UseBridges && node_is_a_configured_bridge(node)) entry->is_dir_cache = 1; /* Choose expiry time smudged over the past month. The goal here * is to a) spread out when Tor clients rotate their guards, so they * don't all select them on the same day, and b) avoid leaving a * precise timestamp in the state file about when we first picked * this guard. For details, see the Jan 2010 or-dev thread. */ time_t now = time(NULL); entry->chosen_on_date = crypto_rand_time_range(now - 3600*24*30, now); entry->chosen_by_version = tor_strdup(VERSION); /* Are we picking this guard because all of our current guards are * down so we need another one (for_discovery is 1), or because we * decided we need more variety in our guard list (for_discovery is 0)? * * Currently we hack this behavior into place by setting "made_contact" * for guards of the latter variety, so we'll be willing to use any of * them right off the bat. */ if (!for_discovery) entry->made_contact = 1; ((node_t*)node)->using_as_guard = 1; if (prepend) smartlist_insert(entry_guards, 0, entry); else smartlist_add(entry_guards, entry); control_event_guard(entry->nickname, entry->identity, "NEW"); control_event_guard_deferred(); log_entry_guards(LOG_INFO); return node; } /** Choose how many entry guards or directory guards we'll use. If * for_directory 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); } /** If the use of entry guards is configured, choose more entry guards * until we have enough in the list. */ static void pick_entry_guards(const or_options_t *options, int for_directory) { int changed = 0; const int num_needed = decide_num_guards(options, for_directory); tor_assert(entry_guards); while (num_live_entry_guards(for_directory) < num_needed) { if (!add_an_entry_guard(NULL, 0, 0, 0, for_directory)) break; changed = 1; } if (changed) entry_guards_changed(); } /** 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 e. */ static void entry_guard_free(entry_guard_t *e) { if (!e) return; tor_free(e->chosen_by_version); 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 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. */ /* XXXX The "obsolete guards" and "chosen long ago guards" things should * probably be different functions. */ 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); const char *ver = entry->chosen_by_version; const char *msg = NULL; tor_version_t v; int version_is_bad = 0, date_is_bad = 0; if (!ver) { msg = "does not say what version of Tor it was selected by"; version_is_bad = 1; } else if (tor_version_parse(ver, &v)) { msg = "does not seem to be from any recognized version of Tor"; version_is_bad = 1; } 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; } if (version_is_bad || date_is_bad) { /* we need to drop it */ char dbuf[HEX_DIGEST_LEN+1]; tor_assert(msg); base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN); log_fn(version_is_bad ? LOG_NOTICE : LOG_INFO, LD_CIRC, "Entry guard '%s' (%s) %s. (Version=%s.) Replacing it.", entry->nickname, dbuf, msg, ver?escaped(ver):"none"); control_event_guard(entry->nickname, entry->identity, "DROPPED"); entry_guard_free(entry); smartlist_del_keeporder(entry_guards, i--); log_entry_guards(LOG_INFO); changed = 1; } } return changed ? 1 : 0; } /** Remove all entry guards that have been down or unlisted for so * long that we don't think they'll come up again. Return 1 if we * removed any, or 0 if we did nothing. */ static int remove_dead_entry_guards(time_t now) { char dbuf[HEX_DIGEST_LEN+1]; char tbuf[ISO_TIME_LEN+1]; int i; int changed = 0; for (i = 0; i < smartlist_len(entry_guards); ) { entry_guard_t *entry = smartlist_get(entry_guards, i); if (entry->bad_since && ! entry->path_bias_disabled && entry->bad_since + ENTRY_GUARD_REMOVE_AFTER < now) { base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN); format_local_iso_time(tbuf, entry->bad_since); log_info(LD_CIRC, "Entry guard '%s' (%s) has been down or unlisted " "since %s local time; removing.", entry->nickname, dbuf, tbuf); control_event_guard(entry->nickname, entry->identity, "DROPPED"); entry_guard_free(entry); smartlist_del_keeporder(entry_guards, i); log_entry_guards(LOG_INFO); changed = 1; } else ++i; } return changed ? 1 : 0; } /** Remove all currently listed entry guards. So new ones will be chosen. */ void remove_all_entry_guards(void) { char dbuf[HEX_DIGEST_LEN+1]; while (smartlist_len(entry_guards)) { entry_guard_t *entry = smartlist_get(entry_guards, 0); base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN); log_info(LD_CIRC, "Entry guard '%s' (%s) has been dropped.", entry->nickname, dbuf); control_event_guard(entry->nickname, entry->identity, "DROPPED"); entry_guard_free(entry); smartlist_del(entry_guards, 0); } log_entry_guards(LOG_INFO); entry_guards_changed(); } /** A new directory or router-status has arrived; update the down/listed * status of the entry guards. * * An entry is 'down' if the directory lists it as nonrunning. * An entry is 'unlisted' if the directory doesn't include it. * * Don't call this on startup; only on a fresh download. Otherwise we'll * think that things are unlisted. */ void entry_guards_compute_status(const or_options_t *options, time_t now) { int changed = 0; digestmap_t *reasons; if (! entry_guards) return; if (options->EntryNodes) /* reshuffle the entry guard list if needed */ entry_nodes_should_be_added(); reasons = digestmap_new(); SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) { const node_t *r = node_get_by_id(entry->identity); const char *reason = NULL; if (entry_guard_set_status(entry, r, now, options, &reason)) changed = 1; if (entry->bad_since) tor_assert(reason); if (reason) digestmap_set(reasons, entry->identity, (char*)reason); } SMARTLIST_FOREACH_END(entry); if (remove_dead_entry_guards(now)) changed = 1; if (remove_obsolete_entry_guards(now)) changed = 1; if (changed) { SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) { const char *reason = digestmap_get(reasons, entry->identity); const char *live_msg = ""; const node_t *r = entry_is_live(entry, ENTRY_NEED_CAPACITY, &live_msg); log_info(LD_CIRC, "Summary: Entry %s [%s] is %s, %s%s%s, and %s%s.", entry->nickname, hex_str(entry->identity, DIGEST_LEN), entry->unreachable_since ? "unreachable" : "reachable", entry->bad_since ? "unusable" : "usable", reason ? ", ": "", reason ? reason : "", r ? "live" : "not live / ", r ? "" : live_msg); } SMARTLIST_FOREACH_END(entry); log_info(LD_CIRC, " (%d/%d entry guards are usable/new)", num_live_entry_guards(0), smartlist_len(entry_guards)); log_entry_guards(LOG_INFO); entry_guards_changed(); } digestmap_free(reasons, NULL); } /** Called when a connection to an OR with the identity digest digest * is established (succeeded==1) or has failed (succeeded==0). * If the OR is an entry, change that entry's up/down status. * Return 0 normally, or -1 if we want to tear down the new connection. * * If mark_relay_status, also call router_set_status() on this * relay. */ /* XXX We could change succeeded and mark_relay_status into 'int flags'. * Too many boolean arguments is a recipe for confusion. */ int entry_guard_register_connect_status(const char *digest, int succeeded, int mark_relay_status, time_t now) { int changed = 0; int refuse_conn = 0; int first_contact = 0; entry_guard_t *entry = NULL; int idx = -1; char buf[HEX_DIGEST_LEN+1]; if (! entry_guards) return 0; SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { tor_assert(e); if (tor_memeq(e->identity, digest, DIGEST_LEN)) { entry = e; idx = e_sl_idx; break; } } SMARTLIST_FOREACH_END(e); if (!entry) return 0; base16_encode(buf, sizeof(buf), entry->identity, DIGEST_LEN); if (succeeded) { if (entry->unreachable_since) { log_info(LD_CIRC, "Entry guard '%s' (%s) is now reachable again. Good.", entry->nickname, buf); entry->can_retry = 0; entry->unreachable_since = 0; entry->last_attempted = now; control_event_guard(entry->nickname, entry->identity, "UP"); changed = 1; } if (!entry->made_contact) { entry->made_contact = 1; first_contact = changed = 1; } } else { /* ! succeeded */ if (!entry->made_contact) { /* We've never connected to this one. */ log_info(LD_CIRC, "Connection to never-contacted entry guard '%s' (%s) failed. " "Removing from the list. %d/%d entry guards usable/new.", entry->nickname, buf, num_live_entry_guards(0)-1, smartlist_len(entry_guards)-1); control_event_guard(entry->nickname, entry->identity, "DROPPED"); entry_guard_free(entry); smartlist_del_keeporder(entry_guards, idx); log_entry_guards(LOG_INFO); changed = 1; } else if (!entry->unreachable_since) { log_info(LD_CIRC, "Unable to connect to entry guard '%s' (%s). " "Marking as unreachable.", entry->nickname, buf); entry->unreachable_since = entry->last_attempted = now; control_event_guard(entry->nickname, entry->identity, "DOWN"); changed = 1; entry->can_retry = 0; /* We gave it an early chance; no good. */ } else { char tbuf[ISO_TIME_LEN+1]; format_iso_time(tbuf, entry->unreachable_since); log_debug(LD_CIRC, "Failed to connect to unreachable entry guard " "'%s' (%s). It has been unreachable since %s.", entry->nickname, buf, tbuf); entry->last_attempted = now; entry->can_retry = 0; /* We gave it an early chance; no good. */ } } /* if the caller asked us to, also update the is_running flags for this * relay */ if (mark_relay_status) router_set_status(digest, succeeded); if (first_contact) { /* We've just added a new long-term entry guard. Perhaps the network just * came back? We should give our earlier entries another try too, * and close this connection so we don't use it before we've given * the others a shot. */ SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { if (e == entry) break; if (e->made_contact) { const char *msg; const node_t *r = entry_is_live(e, ENTRY_NEED_CAPACITY | ENTRY_ASSUME_REACHABLE, &msg); if (r && e->unreachable_since) { refuse_conn = 1; e->can_retry = 1; } } } SMARTLIST_FOREACH_END(e); if (refuse_conn) { log_info(LD_CIRC, "Connected to new entry guard '%s' (%s). Marking earlier " "entry guards up. %d/%d entry guards usable/new.", entry->nickname, buf, num_live_entry_guards(0), smartlist_len(entry_guards)); log_entry_guards(LOG_INFO); changed = 1; } } if (changed) entry_guards_changed(); return refuse_conn ? -1 : 0; } /** When we try to choose an entry guard, should we parse and add * config's EntryNodes first? */ static int should_add_entry_nodes = 0; /** Called when the value of EntryNodes changes in our configuration. */ void entry_nodes_should_be_added(void) { log_info(LD_CIRC, "EntryNodes config option set. Putting configured " "relays at the front of the entry guard list."); should_add_entry_nodes = 1; } /** Update the using_as_guard fields of all the nodes. We do this after we * remove entry guards from the list: This is the only function that clears * the using_as_guard field. */ static void update_node_guard_status(void) { smartlist_t *nodes = nodelist_get_list(); SMARTLIST_FOREACH(nodes, node_t *, node, node->using_as_guard = 0); SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) { node_t *node = node_get_mutable_by_id(entry->identity); if (node) node->using_as_guard = 1; } SMARTLIST_FOREACH_END(entry); } /** Adjust the entry guards list so that it only contains entries from * EntryNodes, adding new entries from EntryNodes to the list as needed. */ STATIC void entry_guards_set_from_config(const or_options_t *options) { smartlist_t *entry_nodes, *worse_entry_nodes, *entry_fps; smartlist_t *old_entry_guards_on_list, *old_entry_guards_not_on_list; const int numentryguards = decide_num_guards(options, 0); tor_assert(entry_guards); should_add_entry_nodes = 0; if (!options->EntryNodes) { /* It's possible that a controller set EntryNodes, thus making * should_add_entry_nodes set, then cleared it again, all before the * call to choose_random_entry() that triggered us. If so, just return. */ return; } { char *string = routerset_to_string(options->EntryNodes); log_info(LD_CIRC,"Adding configured EntryNodes '%s'.", string); tor_free(string); } entry_nodes = smartlist_new(); worse_entry_nodes = smartlist_new(); entry_fps = smartlist_new(); old_entry_guards_on_list = smartlist_new(); old_entry_guards_not_on_list = smartlist_new(); /* Split entry guards into those on the list and those not. */ routerset_get_all_nodes(entry_nodes, options->EntryNodes, options->ExcludeNodes, 0); SMARTLIST_FOREACH(entry_nodes, const node_t *,node, smartlist_add(entry_fps, (void*)node->identity)); SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, { if (smartlist_contains_digest(entry_fps, e->identity)) smartlist_add(old_entry_guards_on_list, e); else smartlist_add(old_entry_guards_not_on_list, e); }); /* Remove all currently configured guard nodes, excluded nodes, unreachable * nodes, or non-Guard nodes from entry_nodes. */ SMARTLIST_FOREACH_BEGIN(entry_nodes, const node_t *, node) { if (entry_guard_get_by_id_digest(node->identity)) { SMARTLIST_DEL_CURRENT(entry_nodes, node); continue; } else if (routerset_contains_node(options->ExcludeNodes, node)) { SMARTLIST_DEL_CURRENT(entry_nodes, node); continue; } else if (!fascist_firewall_allows_node(node, FIREWALL_OR_CONNECTION, 0)) { SMARTLIST_DEL_CURRENT(entry_nodes, node); continue; } else if (! node->is_possible_guard) { smartlist_add(worse_entry_nodes, (node_t*)node); SMARTLIST_DEL_CURRENT(entry_nodes, node); } } SMARTLIST_FOREACH_END(node); /* Now build the new entry_guards list. */ smartlist_clear(entry_guards); /* First, the previously configured guards that are in EntryNodes. */ smartlist_add_all(entry_guards, old_entry_guards_on_list); /* Next, scramble the rest of EntryNodes, putting the guards first. */ smartlist_shuffle(entry_nodes); smartlist_shuffle(worse_entry_nodes); smartlist_add_all(entry_nodes, worse_entry_nodes); /* Next, the rest of EntryNodes */ SMARTLIST_FOREACH_BEGIN(entry_nodes, const node_t *, node) { add_an_entry_guard(node, 0, 0, 1, 0); if (smartlist_len(entry_guards) > numentryguards * 10) break; } SMARTLIST_FOREACH_END(node); log_notice(LD_GENERAL, "%d entries in guards", smartlist_len(entry_guards)); /* Finally, free the remaining previously configured guards that are not in * EntryNodes. */ SMARTLIST_FOREACH(old_entry_guards_not_on_list, entry_guard_t *, e, entry_guard_free(e)); update_node_guard_status(); smartlist_free(entry_nodes); smartlist_free(worse_entry_nodes); smartlist_free(entry_fps); smartlist_free(old_entry_guards_on_list); smartlist_free(old_entry_guards_not_on_list); entry_guards_changed(); } /** Return 0 if we're fine adding arbitrary routers out of the * directory to our entry guard list, or return 1 if we have a * list already and we must stick to it. */ int entry_list_is_constrained(const or_options_t *options) { if (options->EntryNodes) return 1; if (options->UseBridges) return 1; return 0; } /** Pick a live (up and listed) entry guard from entry_guards. If * state is non-NULL, this is for a specific circuit -- * make sure not to pick this circuit's exit or any node in the * exit's family. If state is NULL, we're looking for a random * guard (likely a bridge). If dirinfo is not NO_DIRINFO (zero), * then only select from nodes that know how to answer directory questions * of that type. */ const node_t * choose_random_entry(cpath_build_state_t *state) { return choose_random_entry_impl(state, 0, NO_DIRINFO, NULL); } /** Pick a live (up and listed) directory guard from entry_guards for * downloading information of type type. */ const node_t * choose_random_dirguard(dirinfo_type_t type) { return choose_random_entry_impl(NULL, 1, type, NULL); } /** Filter all_entry_guards for usable entry guards and put them * in live_entry_guards. We filter based on whether the node is * currently alive, and on whether it satisfies the restrictions * imposed by the other arguments of this function. * * We don't place more guards than NumEntryGuards in live_entry_guards. * * If chosen_exit is set, it contains the exit node of this * circuit. Make sure to not use it or its family as an entry guard. * * If need_uptime is set, we are looking for a stable entry guard. * if need_capacity is set, we are looking for a fast entry guard. * * The rest of the arguments are the same as in choose_random_entry_impl(). * * Return 1 if we should choose a guard right away. Return 0 if we * should try to add more nodes to our list before deciding on a * guard. */ STATIC int populate_live_entry_guards(smartlist_t *live_entry_guards, const smartlist_t *all_entry_guards, const node_t *chosen_exit, dirinfo_type_t dirinfo_type, int for_directory, int need_uptime, int need_capacity) { const or_options_t *options = get_options(); const node_t *node = NULL; const int num_needed = decide_num_guards(options, for_directory); smartlist_t *exit_family = smartlist_new(); int retval = 0; entry_is_live_flags_t entry_flags = 0; (void) dirinfo_type; { /* Set the flags we want our entry node to have */ if (need_uptime) { entry_flags |= ENTRY_NEED_UPTIME; } if (need_capacity) { entry_flags |= ENTRY_NEED_CAPACITY; } if (!for_directory) { entry_flags |= ENTRY_NEED_DESCRIPTOR; } } tor_assert(all_entry_guards); if (chosen_exit) { nodelist_add_node_and_family(exit_family, chosen_exit); } SMARTLIST_FOREACH_BEGIN(all_entry_guards, const entry_guard_t *, entry) { const char *msg; node = entry_is_live(entry, entry_flags, &msg); if (!node) continue; /* down, no point */ if (for_directory) { if (!entry->is_dir_cache) continue; /* We need a directory and didn't get one. */ } if (node == chosen_exit) continue; /* don't pick the same node for entry and exit */ if (smartlist_contains(exit_family, node)) continue; /* avoid relays that are family members of our exit */ smartlist_add(live_entry_guards, (void*)node); if (!entry->made_contact) { /* Always start with the first not-yet-contacted entry * guard. Otherwise we might add several new ones, pick * the second new one, and now we've expanded our entry * guard list without needing to. */ retval = 1; goto done; } if (smartlist_len(live_entry_guards) >= num_needed) { retval = 1; goto done; /* We picked enough entry guards. Done! */ } } SMARTLIST_FOREACH_END(entry); done: smartlist_free(exit_family); return retval; } /** Pick a node to be used as the entry guard of a circuit. * * If state is set, it contains the information we know about * the upcoming circuit. * * If for_directory is set, we are looking for a directory guard. * * dirinfo_type contains the kind of directory information we * are looking for in our node, or NO_DIRINFO (zero) if we are not * looking for any particular directory information (when set to * NO_DIRINFO, the dirinfo_type filter is ignored). * * If n_options_out is set, we set it to the number of * candidate guard nodes we had before picking a specific guard node. * * On success, return the node that should be used as the entry guard * of the circuit. Return NULL if no such node could be found. * * Helper for choose_random{entry,dirguard}. */ static const node_t * choose_random_entry_impl(cpath_build_state_t *state, int for_directory, dirinfo_type_t dirinfo_type, int *n_options_out) { const or_options_t *options = get_options(); smartlist_t *live_entry_guards = smartlist_new(); const node_t *chosen_exit = state?build_state_get_exit_node(state) : NULL; const node_t *node = NULL; int need_uptime = state ? state->need_uptime : 0; int need_capacity = state ? state->need_capacity : 0; int preferred_min = 0; const int num_needed = decide_num_guards(options, for_directory); int retval = 0; if (n_options_out) *n_options_out = 0; if (!entry_guards) entry_guards = smartlist_new(); if (should_add_entry_nodes) entry_guards_set_from_config(options); if (!entry_list_is_constrained(options) && smartlist_len(entry_guards) < num_needed) pick_entry_guards(options, for_directory); retry: smartlist_clear(live_entry_guards); /* Populate the list of live entry guards so that we pick one of them. */ retval = populate_live_entry_guards(live_entry_guards, entry_guards, chosen_exit, dirinfo_type, for_directory, need_uptime, need_capacity); if (retval == 1) { /* We should choose a guard right now. */ goto choose_and_finish; } if (entry_list_is_constrained(options)) { /* If we prefer the entry nodes we've got, and we have at least * one choice, that's great. Use it. */ preferred_min = 1; } else { /* Try to have at least 2 choices available. This way we don't * get stuck with a single live-but-crummy entry and just keep * using it. * (We might get 2 live-but-crummy entry guards, but so be it.) */ preferred_min = 2; } if (smartlist_len(live_entry_guards) < preferred_min) { if (!entry_list_is_constrained(options)) { /* still no? try adding a new entry then */ /* XXX if guard doesn't imply fast and stable, then we need * to tell add_an_entry_guard below what we want, or it might * be a long time til we get it. -RD */ node = add_an_entry_guard(NULL, 0, 0, 1, for_directory); if (node) { entry_guards_changed(); /* XXX we start over here in case the new node we added shares * a family with our exit node. There's a chance that we'll just * load up on entry guards here, if the network we're using is * one big family. Perhaps we should teach add_an_entry_guard() * to understand nodes-to-avoid-if-possible? -RD */ goto retry; } } if (!node && need_uptime) { need_uptime = 0; /* try without that requirement */ goto retry; } if (!node && need_capacity) { /* still no? last attempt, try without requiring capacity */ need_capacity = 0; goto retry; } /* live_entry_guards may be empty below. Oh well, we tried. */ } choose_and_finish: if (entry_list_is_constrained(options)) { /* We need to weight by bandwidth, because our bridges or entryguards * were not already selected proportional to their bandwidth. */ node = node_sl_choose_by_bandwidth(live_entry_guards, WEIGHT_FOR_GUARD); } else { /* We choose uniformly at random here, because choose_good_entry_server() * already weights its choices by bandwidth, so we don't want to * *double*-weight our guard selection. */ node = smartlist_choose(live_entry_guards); } if (n_options_out) *n_options_out = smartlist_len(live_entry_guards); smartlist_free(live_entry_guards); return node; } /** Parse state and learn about the entry guards it describes. * If set is true, and there are no errors, replace the global * entry_list with what we find. * On success, return 0. On failure, alloc into *msg a string * describing the error, and return -1. */ int entry_guards_parse_state(or_state_t *state, int set, char **msg) { entry_guard_t *node = NULL; smartlist_t *new_entry_guards = smartlist_new(); config_line_t *line; time_t now = time(NULL); const char *state_version = state->TorVersion; digestmap_t *added_by = digestmap_new(); *msg = NULL; for (line = state->EntryGuards; line; line = line->next) { if (!strcasecmp(line->key, "EntryGuard")) { smartlist_t *args = smartlist_new(); node = tor_malloc_zero(sizeof(entry_guard_t)); /* all entry guards on disk have been contacted */ node->made_contact = 1; smartlist_add(new_entry_guards, node); smartlist_split_string(args, line->value, " ", SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); if (smartlist_len(args)<2) { *msg = tor_strdup("Unable to parse entry nodes: " "Too few arguments to EntryGuard"); } else if (!is_legal_nickname(smartlist_get(args,0))) { *msg = tor_strdup("Unable to parse entry nodes: " "Bad nickname for EntryGuard"); } else { strlcpy(node->nickname, smartlist_get(args,0), MAX_NICKNAME_LEN+1); if (base16_decode(node->identity, DIGEST_LEN, smartlist_get(args,1), strlen(smartlist_get(args,1))) != DIGEST_LEN) { *msg = tor_strdup("Unable to parse entry nodes: " "Bad hex digest for EntryGuard"); } } if (smartlist_len(args) >= 3) { const char *is_cache = smartlist_get(args, 2); if (!strcasecmp(is_cache, "DirCache")) { node->is_dir_cache = 1; } else if (!strcasecmp(is_cache, "NoDirCache")) { node->is_dir_cache = 0; } else { log_warn(LD_CONFIG, "Bogus third argument to EntryGuard line: %s", escaped(is_cache)); } } SMARTLIST_FOREACH(args, char*, cp, tor_free(cp)); smartlist_free(args); if (*msg) break; } else if (!strcasecmp(line->key, "EntryGuardDownSince") || !strcasecmp(line->key, "EntryGuardUnlistedSince")) { time_t when; time_t last_try = 0; if (!node) { *msg = tor_strdup("Unable to parse entry nodes: " "EntryGuardDownSince/UnlistedSince without EntryGuard"); break; } if (parse_iso_time_(line->value, &when, 0)<0) { *msg = tor_strdup("Unable to parse entry nodes: " "Bad time in EntryGuardDownSince/UnlistedSince"); break; } if (when > now) { /* It's a bad idea to believe info in the future: you can wind * up with timeouts that aren't allowed to happen for years. */ continue; } if (strlen(line->value) >= ISO_TIME_LEN+ISO_TIME_LEN+1) { /* ignore failure */ (void) parse_iso_time(line->value+ISO_TIME_LEN+1, &last_try); } if (!strcasecmp(line->key, "EntryGuardDownSince")) { node->unreachable_since = when; node->last_attempted = last_try; } else { node->bad_since = when; } } else if (!strcasecmp(line->key, "EntryGuardAddedBy")) { char d[DIGEST_LEN]; /* format is digest version date */ if (strlen(line->value) < HEX_DIGEST_LEN+1+1+1+ISO_TIME_LEN) { log_warn(LD_BUG, "EntryGuardAddedBy line is not long enough."); continue; } if (base16_decode(d, sizeof(d), line->value, HEX_DIGEST_LEN) != sizeof(d) || line->value[HEX_DIGEST_LEN] != ' ') { log_warn(LD_BUG, "EntryGuardAddedBy line %s does not begin with " "hex digest", escaped(line->value)); continue; } digestmap_set(added_by, d, tor_strdup(line->value+HEX_DIGEST_LEN+1)); } else if (!strcasecmp(line->key, "EntryGuardPathUseBias")) { const or_options_t *options = get_options(); double use_cnt, success_cnt; if (!node) { *msg = tor_strdup("Unable to parse entry nodes: " "EntryGuardPathUseBias without EntryGuard"); break; } if (tor_sscanf(line->value, "%lf %lf", &use_cnt, &success_cnt) != 2) { log_info(LD_GENERAL, "Malformed path use bias line for node %s", node->nickname); continue; } if (use_cnt < success_cnt) { int severity = LOG_INFO; /* If this state file was written by a Tor that would have * already fixed it, then the overcounting bug is still there.. */ if (tor_version_as_new_as(state_version, "0.2.4.13-alpha")) { severity = LOG_NOTICE; } log_fn(severity, LD_BUG, "State file contains unexpectedly high usage success " "counts %lf/%lf for Guard %s ($%s)", success_cnt, use_cnt, node->nickname, hex_str(node->identity, DIGEST_LEN)); success_cnt = use_cnt; } node->use_attempts = use_cnt; node->use_successes = success_cnt; log_info(LD_GENERAL, "Read %f/%f path use bias for node %s", node->use_successes, node->use_attempts, node->nickname); /* Note: We rely on the < comparison here to allow us to set a 0 * rate and disable the feature entirely. If refactoring, don't * change to <= */ if (pathbias_get_use_success_count(node)/node->use_attempts < pathbias_get_extreme_use_rate(options) && pathbias_get_dropguards(options)) { node->path_bias_disabled = 1; log_info(LD_GENERAL, "Path use bias is too high (%f/%f); disabling node %s", node->circ_successes, node->circ_attempts, node->nickname); } } else if (!strcasecmp(line->key, "EntryGuardPathBias")) { const or_options_t *options = get_options(); double hop_cnt, success_cnt, timeouts, collapsed, successful_closed, unusable; if (!node) { *msg = tor_strdup("Unable to parse entry nodes: " "EntryGuardPathBias without EntryGuard"); break; } /* First try 3 params, then 2. */ /* In the long run: circuit_success ~= successful_circuit_close + * collapsed_circuits + * unusable_circuits */ if (tor_sscanf(line->value, "%lf %lf %lf %lf %lf %lf", &hop_cnt, &success_cnt, &successful_closed, &collapsed, &unusable, &timeouts) != 6) { int old_success, old_hops; if (tor_sscanf(line->value, "%u %u", &old_success, &old_hops) != 2) { continue; } log_info(LD_GENERAL, "Reading old-style EntryGuardPathBias %s", escaped(line->value)); success_cnt = old_success; successful_closed = old_success; hop_cnt = old_hops; timeouts = 0; collapsed = 0; unusable = 0; } if (hop_cnt < success_cnt) { int severity = LOG_INFO; /* If this state file was written by a Tor that would have * already fixed it, then the overcounting bug is still there.. */ if (tor_version_as_new_as(state_version, "0.2.4.13-alpha")) { severity = LOG_NOTICE; } log_fn(severity, LD_BUG, "State file contains unexpectedly high success counts " "%lf/%lf for Guard %s ($%s)", success_cnt, hop_cnt, node->nickname, hex_str(node->identity, DIGEST_LEN)); success_cnt = hop_cnt; } node->circ_attempts = hop_cnt; node->circ_successes = success_cnt; node->successful_circuits_closed = successful_closed; node->timeouts = timeouts; node->collapsed_circuits = collapsed; node->unusable_circuits = unusable; log_info(LD_GENERAL, "Read %f/%f path bias for node %s", node->circ_successes, node->circ_attempts, node->nickname); /* Note: We rely on the < comparison here to allow us to set a 0 * rate and disable the feature entirely. If refactoring, don't * change to <= */ if (pathbias_get_close_success_count(node)/node->circ_attempts < pathbias_get_extreme_rate(options) && pathbias_get_dropguards(options)) { node->path_bias_disabled = 1; log_info(LD_GENERAL, "Path bias is too high (%f/%f); disabling node %s", node->circ_successes, node->circ_attempts, node->nickname); } } else { log_warn(LD_BUG, "Unexpected key %s", line->key); } } SMARTLIST_FOREACH_BEGIN(new_entry_guards, entry_guard_t *, e) { char *sp; char *val = digestmap_get(added_by, e->identity); if (val && (sp = strchr(val, ' '))) { time_t when; *sp++ = '\0'; if (parse_iso_time(sp, &when)<0) { log_warn(LD_BUG, "Can't read time %s in EntryGuardAddedBy", sp); } else { e->chosen_by_version = tor_strdup(val); e->chosen_on_date = when; } } else { if (state_version) { e->chosen_on_date = crypto_rand_time_range(now - 3600*24*30, now); e->chosen_by_version = tor_strdup(state_version); } } if (e->path_bias_disabled && !e->bad_since) e->bad_since = time(NULL); } SMARTLIST_FOREACH_END(e); if (*msg || !set) { SMARTLIST_FOREACH(new_entry_guards, entry_guard_t *, e, entry_guard_free(e)); smartlist_free(new_entry_guards); } else { /* !err && set */ if (entry_guards) { SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, entry_guard_free(e)); smartlist_free(entry_guards); } entry_guards = new_entry_guards; entry_guards_dirty = 0; /* XXX hand new_entry_guards to this func, and move it up a * few lines, so we don't have to re-dirty it */ if (remove_obsolete_entry_guards(now)) entry_guards_dirty = 1; update_node_guard_status(); } digestmap_free(added_by, tor_free_); return *msg ? -1 : 0; } /** How long will we let a change in our guard nodes stay un-saved * when we are trying to avoid disk writes? */ #define SLOW_GUARD_STATE_FLUSH_TIME 600 /** How long will we let a change in our guard nodes stay un-saved * when we are not trying to avoid disk writes? */ #define FAST_GUARD_STATE_FLUSH_TIME 30 /** Our list of entry guards has changed, or some element of one * of our entry guards has changed. Write the changes to disk within * the next few minutes. */ void entry_guards_changed(void) { time_t when; entry_guards_dirty = 1; if (get_options()->AvoidDiskWrites) when = time(NULL) + SLOW_GUARD_STATE_FLUSH_TIME; else when = time(NULL) + FAST_GUARD_STATE_FLUSH_TIME; /* or_state_save() will call entry_guards_update_state(). */ or_state_mark_dirty(get_or_state(), when); } /** If the entry guard info has not changed, do nothing and return. * Otherwise, free the EntryGuards piece of state and create * a new one out of the global entry_guards list, and then mark * state dirty so it will get saved to disk. */ void entry_guards_update_state(or_state_t *state) { config_line_t **next, *line; if (! entry_guards_dirty) return; config_free_lines(state->EntryGuards); next = &state->EntryGuards; *next = NULL; if (!entry_guards) entry_guards = smartlist_new(); SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { char dbuf[HEX_DIGEST_LEN+1]; if (!e->made_contact) continue; /* don't write this one to disk */ *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuard"); base16_encode(dbuf, sizeof(dbuf), e->identity, DIGEST_LEN); tor_asprintf(&line->value, "%s %s %sDirCache", e->nickname, dbuf, e->is_dir_cache ? "" : "No"); next = &(line->next); if (e->unreachable_since) { *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuardDownSince"); line->value = tor_malloc(ISO_TIME_LEN+1+ISO_TIME_LEN+1); format_iso_time(line->value, e->unreachable_since); if (e->last_attempted) { line->value[ISO_TIME_LEN] = ' '; format_iso_time(line->value+ISO_TIME_LEN+1, e->last_attempted); } next = &(line->next); } if (e->bad_since) { *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuardUnlistedSince"); line->value = tor_malloc(ISO_TIME_LEN+1); format_iso_time(line->value, e->bad_since); next = &(line->next); } if (e->chosen_on_date && e->chosen_by_version && !strchr(e->chosen_by_version, ' ')) { char d[HEX_DIGEST_LEN+1]; char t[ISO_TIME_LEN+1]; *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuardAddedBy"); base16_encode(d, sizeof(d), e->identity, DIGEST_LEN); format_iso_time(t, e->chosen_on_date); tor_asprintf(&line->value, "%s %s %s", d, e->chosen_by_version, t); next = &(line->next); } if (e->circ_attempts > 0) { *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuardPathBias"); /* In the long run: circuit_success ~= successful_circuit_close + * collapsed_circuits + * unusable_circuits */ tor_asprintf(&line->value, "%f %f %f %f %f %f", e->circ_attempts, e->circ_successes, pathbias_get_close_success_count(e), e->collapsed_circuits, e->unusable_circuits, e->timeouts); next = &(line->next); } if (e->use_attempts > 0) { *next = line = tor_malloc_zero(sizeof(config_line_t)); line->key = tor_strdup("EntryGuardPathUseBias"); tor_asprintf(&line->value, "%f %f", e->use_attempts, pathbias_get_use_success_count(e)); next = &(line->next); } } SMARTLIST_FOREACH_END(e); if (!get_options()->AvoidDiskWrites) or_state_mark_dirty(get_or_state(), 0); entry_guards_dirty = 0; } /** If question is the string "entry-guards", then dump * to *answer a newly allocated string describing all of * the nodes in the global entry_guards list. See control-spec.txt * for details. * For backward compatibility, we also handle the string "helper-nodes". * */ int getinfo_helper_entry_guards(control_connection_t *conn, const char *question, char **answer, const char **errmsg) { (void) conn; (void) errmsg; if (!strcmp(question,"entry-guards") || !strcmp(question,"helper-nodes")) { smartlist_t *sl = smartlist_new(); char tbuf[ISO_TIME_LEN+1]; char nbuf[MAX_VERBOSE_NICKNAME_LEN+1]; if (!entry_guards) entry_guards = smartlist_new(); SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { const char *status = NULL; time_t when = 0; const node_t *node; if (!e->made_contact) { status = "never-connected"; } else if (e->bad_since) { when = e->bad_since; status = "unusable"; } else if (e->unreachable_since) { when = e->unreachable_since; status = "down"; } else { status = "up"; } node = node_get_by_id(e->identity); if (node) { node_get_verbose_nickname(node, nbuf); } else { nbuf[0] = '$'; base16_encode(nbuf+1, sizeof(nbuf)-1, e->identity, DIGEST_LEN); /* e->nickname field is not very reliable if we don't know about * this router any longer; don't include it. */ } if (when) { format_iso_time(tbuf, when); smartlist_add_asprintf(sl, "%s %s %s\n", nbuf, status, tbuf); } else { smartlist_add_asprintf(sl, "%s %s\n", nbuf, status); } } SMARTLIST_FOREACH_END(e); *answer = smartlist_join_strings(sl, "", 0, NULL); SMARTLIST_FOREACH(sl, char *, c, tor_free(c)); smartlist_free(sl); } return 0; } /** Return 0 if we should apply guardfraction information found in the * consensus. A specific consensus can be specified with the * ns 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. * * Quoting from proposal236: * * Let Wpf denote the weight from the 'bandwidth-weights' line a * client would apply to N for position p if it had the guard * flag, Wpn the weight if it did not have the guard flag, and B the * measured bandwidth of N in the consensus. Then instead of choosing * N for position p proportionally to Wpf*B or Wpn*B, clients should * choose N proportionally to F*Wpf*B + (1-F)*Wpn*B. * * This function fills the guardfraction_bw structure. It sets * guard_bw to F*B and non_guard_bw to (1-F)*B. */ void guard_get_guardfraction_bandwidth(guardfraction_bandwidth_t *guardfraction_bw, int orig_bandwidth, uint32_t guardfraction_percentage) { double guardfraction_fraction; /* Turn the percentage into a fraction. */ tor_assert(guardfraction_percentage <= 100); guardfraction_fraction = guardfraction_percentage / 100.0; long guard_bw = tor_lround(guardfraction_fraction * orig_bandwidth); tor_assert(guard_bw <= INT_MAX); guardfraction_bw->guard_bw = (int) guard_bw; guardfraction_bw->non_guard_bw = orig_bandwidth - (int) guard_bw; } /** A list of configured bridges. Whenever we actually get a descriptor * for one, we add it as an entry guard. Note that the order of bridges * in this list does not necessarily correspond to the order of bridges * in the torrc. */ static smartlist_t *bridge_list = NULL; /** Mark every entry of the bridge list to be removed on our next call to * sweep_bridge_list unless it has first been un-marked. */ void mark_bridge_list(void) { if (!bridge_list) bridge_list = smartlist_new(); SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b, b->marked_for_removal = 1); } /** Remove every entry of the bridge list that was marked with * mark_bridge_list if it has not subsequently been un-marked. */ void sweep_bridge_list(void) { if (!bridge_list) bridge_list = smartlist_new(); SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) { if (b->marked_for_removal) { SMARTLIST_DEL_CURRENT(bridge_list, b); bridge_free(b); } } SMARTLIST_FOREACH_END(b); } /** Initialize the bridge list to empty, creating it if needed. */ static void clear_bridge_list(void) { if (!bridge_list) bridge_list = smartlist_new(); SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b, bridge_free(b)); smartlist_clear(bridge_list); } /** Free the bridge bridge. */ static void bridge_free(bridge_info_t *bridge) { if (!bridge) return; tor_free(bridge->transport_name); if (bridge->socks_args) { SMARTLIST_FOREACH(bridge->socks_args, char*, s, tor_free(s)); smartlist_free(bridge->socks_args); } tor_free(bridge); } /** If we have a bridge configured whose digest matches digest, or a * bridge with no known digest whose address matches any of the * tor_addr_port_t's in orports, return that bridge. Else return * NULL. */ static bridge_info_t * get_configured_bridge_by_orports_digest(const char *digest, const smartlist_t *orports) { if (!bridge_list) return NULL; SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) { if (tor_digest_is_zero(bridge->identity)) { SMARTLIST_FOREACH_BEGIN(orports, tor_addr_port_t *, ap) { if (tor_addr_compare(&bridge->addr, &ap->addr, CMP_EXACT) == 0 && bridge->port == ap->port) return bridge; } SMARTLIST_FOREACH_END(ap); } if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN)) return bridge; } SMARTLIST_FOREACH_END(bridge); return NULL; } /** If we have a bridge configured whose digest matches digest, or a * bridge with no known digest whose address matches addr:port, * return that bridge. Else return NULL. If digest is NULL, check for * address/port matches only. */ static bridge_info_t * get_configured_bridge_by_addr_port_digest(const tor_addr_t *addr, uint16_t port, const char *digest) { if (!bridge_list) return NULL; SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) { if ((tor_digest_is_zero(bridge->identity) || digest == NULL) && !tor_addr_compare(&bridge->addr, addr, CMP_EXACT) && bridge->port == port) return bridge; if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN)) return bridge; } SMARTLIST_FOREACH_END(bridge); return NULL; } /** If we have a bridge configured whose digest matches digest, or a * bridge with no known digest whose address matches addr:port, * return 1. Else return 0. If digest is NULL, check for * address/port matches only. */ int addr_is_a_configured_bridge(const tor_addr_t *addr, uint16_t port, const char *digest) { tor_assert(addr); return get_configured_bridge_by_addr_port_digest(addr, port, digest) ? 1 : 0; } /** If we have a bridge configured whose digest matches * ei->identity_digest, or a bridge with no known digest whose address * matches ei->addr:ei->port, return 1. Else return 0. * If ei->onion_key is NULL, check for address/port matches only. */ int extend_info_is_a_configured_bridge(const extend_info_t *ei) { const char *digest = ei->onion_key ? ei->identity_digest : NULL; return addr_is_a_configured_bridge(&ei->addr, ei->port, digest); } /** Wrapper around get_configured_bridge_by_addr_port_digest() to look * it up via router descriptor ri. */ static bridge_info_t * get_configured_bridge_by_routerinfo(const routerinfo_t *ri) { bridge_info_t *bi = NULL; smartlist_t *orports = router_get_all_orports(ri); bi = get_configured_bridge_by_orports_digest(ri->cache_info.identity_digest, orports); SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p)); smartlist_free(orports); return bi; } /** Return 1 if ri is one of our known bridges, else 0. */ int routerinfo_is_a_configured_bridge(const routerinfo_t *ri) { return get_configured_bridge_by_routerinfo(ri) ? 1 : 0; } /** Return 1 if node is one of our configured bridges, else 0. */ int node_is_a_configured_bridge(const node_t *node) { int retval = 0; smartlist_t *orports = node_get_all_orports(node); retval = get_configured_bridge_by_orports_digest(node->identity, orports) != NULL; SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p)); smartlist_free(orports); return retval; } /** We made a connection to a router at addr:port * without knowing its digest. Its digest turned out to be digest. * If it was a bridge, and we still don't know its digest, record it. */ void learned_router_identity(const tor_addr_t *addr, uint16_t port, const char *digest) { bridge_info_t *bridge = get_configured_bridge_by_addr_port_digest(addr, port, digest); if (bridge && tor_digest_is_zero(bridge->identity)) { char *transport_info = NULL; const char *transport_name = find_transport_name_by_bridge_addrport(addr, port); if (transport_name) tor_asprintf(&transport_info, " (with transport '%s')", transport_name); memcpy(bridge->identity, digest, DIGEST_LEN); log_notice(LD_DIR, "Learned fingerprint %s for bridge %s%s.", hex_str(digest, DIGEST_LEN), fmt_addrport(addr, port), transport_info ? transport_info : ""); tor_free(transport_info); } } /** Return true if bridge has the same identity digest as * digest. If digest is NULL, it matches * bridges with unspecified identity digests. */ static int bridge_has_digest(const bridge_info_t *bridge, const char *digest) { if (digest) return tor_memeq(digest, bridge->identity, DIGEST_LEN); else return tor_digest_is_zero(bridge->identity); } /** We are about to add a new bridge at addr:port, with optional * digest and transport_name. Mark for removal any previously * existing bridge with the same address and port, and warn the user as * appropriate. */ static void bridge_resolve_conflicts(const tor_addr_t *addr, uint16_t port, const char *digest, const char *transport_name) { /* Iterate the already-registered bridge list: If you find a bridge with the same adress and port, mark it for removal. It doesn't make sense to have two active bridges with the same IP:PORT. If the bridge in question has a different digest or transport than digest/transport_name, it's probably a misconfiguration and we should warn the user. */ SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) { if (bridge->marked_for_removal) continue; if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) { bridge->marked_for_removal = 1; if (!bridge_has_digest(bridge, digest) || strcmp_opt(bridge->transport_name, transport_name)) { /* warn the user */ char *bridge_description_new, *bridge_description_old; tor_asprintf(&bridge_description_new, "%s:%s:%s", fmt_addrport(addr, port), digest ? hex_str(digest, DIGEST_LEN) : "", transport_name ? transport_name : ""); tor_asprintf(&bridge_description_old, "%s:%s:%s", fmt_addrport(&bridge->addr, bridge->port), tor_digest_is_zero(bridge->identity) ? "" : hex_str(bridge->identity,DIGEST_LEN), bridge->transport_name ? bridge->transport_name : ""); log_warn(LD_GENERAL,"Tried to add bridge '%s', but we found a conflict" " with the already registered bridge '%s'. We will discard" " the old bridge and keep '%s'. If this is not what you" " wanted, please change your configuration file accordingly.", bridge_description_new, bridge_description_old, bridge_description_new); tor_free(bridge_description_new); tor_free(bridge_description_old); } } } SMARTLIST_FOREACH_END(bridge); } /** Return True if we have a bridge that uses a transport with name * transport_name. */ MOCK_IMPL(int, transport_is_needed, (const char *transport_name)) { if (!bridge_list) return 0; SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) { if (bridge->transport_name && !strcmp(bridge->transport_name, transport_name)) return 1; } SMARTLIST_FOREACH_END(bridge); return 0; } /** Register the bridge information in bridge_line to the * bridge subsystem. Steals reference of bridge_line. */ void bridge_add_from_config(bridge_line_t *bridge_line) { bridge_info_t *b; { /* Log the bridge we are about to register: */ log_debug(LD_GENERAL, "Registering bridge at %s (transport: %s) (%s)", fmt_addrport(&bridge_line->addr, bridge_line->port), bridge_line->transport_name ? bridge_line->transport_name : "no transport", tor_digest_is_zero(bridge_line->digest) ? "no key listed" : hex_str(bridge_line->digest, DIGEST_LEN)); if (bridge_line->socks_args) { /* print socks arguments */ int i = 0; tor_assert(smartlist_len(bridge_line->socks_args) > 0); log_debug(LD_GENERAL, "Bridge uses %d SOCKS arguments:", smartlist_len(bridge_line->socks_args)); SMARTLIST_FOREACH(bridge_line->socks_args, const char *, arg, log_debug(LD_CONFIG, "%d: %s", ++i, arg)); } } bridge_resolve_conflicts(&bridge_line->addr, bridge_line->port, bridge_line->digest, bridge_line->transport_name); b = tor_malloc_zero(sizeof(bridge_info_t)); tor_addr_copy(&b->addr, &bridge_line->addr); b->port = bridge_line->port; memcpy(b->identity, bridge_line->digest, DIGEST_LEN); if (bridge_line->transport_name) b->transport_name = bridge_line->transport_name; b->fetch_status.schedule = DL_SCHED_BRIDGE; b->fetch_status.backoff = DL_SCHED_RANDOM_EXPONENTIAL; b->socks_args = bridge_line->socks_args; if (!bridge_list) bridge_list = smartlist_new(); tor_free(bridge_line); /* Deallocate bridge_line now. */ smartlist_add(bridge_list, b); } /** Return true iff routerset contains the bridge bridge. */ static int routerset_contains_bridge(const routerset_t *routerset, const bridge_info_t *bridge) { int result; extend_info_t *extinfo; tor_assert(bridge); if (!routerset) return 0; extinfo = extend_info_new( NULL, bridge->identity, NULL, NULL, &bridge->addr, bridge->port); result = routerset_contains_extendinfo(routerset, extinfo); extend_info_free(extinfo); return result; } /** If digest is one of our known bridges, return it. */ static bridge_info_t * find_bridge_by_digest(const char *digest) { SMARTLIST_FOREACH(bridge_list, bridge_info_t *, bridge, { if (tor_memeq(bridge->identity, digest, DIGEST_LEN)) return bridge; }); return NULL; } /** Given the addr and port of a bridge, if that bridge * supports a pluggable transport, return its name. Otherwise, return * NULL. */ const char * find_transport_name_by_bridge_addrport(const tor_addr_t *addr, uint16_t port) { if (!bridge_list) return NULL; SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) { if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) return bridge->transport_name; } SMARTLIST_FOREACH_END(bridge); return NULL; } /** If addr and port match the address and port of a * bridge of ours that uses pluggable transports, place its transport * in transport. * * Return 0 on success (found a transport, or found a bridge with no * transport, or found no bridge); return -1 if we should be using a * transport, but the transport could not be found. */ int get_transport_by_bridge_addrport(const tor_addr_t *addr, uint16_t port, const transport_t **transport) { *transport = NULL; if (!bridge_list) return 0; SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) { if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) { /* bridge matched */ if (bridge->transport_name) { /* it also uses pluggable transports */ *transport = transport_get_by_name(bridge->transport_name); if (*transport == NULL) { /* it uses pluggable transports, but the transport could not be found! */ return -1; } return 0; } else { /* bridge matched, but it doesn't use transports. */ break; } } } SMARTLIST_FOREACH_END(bridge); *transport = NULL; return 0; } /** Return a smartlist containing all the SOCKS arguments that we * should pass to the SOCKS proxy. */ const smartlist_t * get_socks_args_by_bridge_addrport(const tor_addr_t *addr, uint16_t port) { bridge_info_t *bridge = get_configured_bridge_by_addr_port_digest(addr, port, NULL); return bridge ? bridge->socks_args : NULL; } /** We need to ask bridge for its server descriptor. */ static void launch_direct_bridge_descriptor_fetch(bridge_info_t *bridge) { const or_options_t *options = get_options(); if (connection_get_by_type_addr_port_purpose( CONN_TYPE_DIR, &bridge->addr, bridge->port, DIR_PURPOSE_FETCH_SERVERDESC)) return; /* it's already on the way */ if (routerset_contains_bridge(options->ExcludeNodes, bridge)) { download_status_mark_impossible(&bridge->fetch_status); log_warn(LD_APP, "Not using bridge at %s: it is in ExcludeNodes.", safe_str_client(fmt_and_decorate_addr(&bridge->addr))); return; } /* Until we get a descriptor for the bridge, we only know one address for * it. */ if (!fascist_firewall_allows_address_addr(&bridge->addr, bridge->port, FIREWALL_OR_CONNECTION, 0, 0)) { log_notice(LD_CONFIG, "Tried to fetch a descriptor directly from a " "bridge, but that bridge is not reachable through our " "firewall."); return; } directory_initiate_command(&bridge->addr, bridge->port, NULL, 0, /*no dirport*/ bridge->identity, DIR_PURPOSE_FETCH_SERVERDESC, ROUTER_PURPOSE_BRIDGE, DIRIND_ONEHOP, "authority.z", NULL, 0, 0); } /** Fetching the bridge descriptor from the bridge authority returned a * "not found". Fall back to trying a direct fetch. */ void retry_bridge_descriptor_fetch_directly(const char *digest) { bridge_info_t *bridge = find_bridge_by_digest(digest); if (!bridge) return; /* not found? oh well. */ launch_direct_bridge_descriptor_fetch(bridge); } /** For each bridge in our list for which we don't currently have a * descriptor, fetch a new copy of its descriptor -- either directly * from the bridge or via a bridge authority. */ void fetch_bridge_descriptors(const or_options_t *options, time_t now) { int num_bridge_auths = get_n_authorities(BRIDGE_DIRINFO); int ask_bridge_directly; int can_use_bridge_authority; if (!bridge_list) return; /* If we still have unconfigured managed proxies, don't go and connect to a bridge. */ if (pt_proxies_configuration_pending()) return; SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) { if (!download_status_is_ready(&bridge->fetch_status, now, IMPOSSIBLE_TO_DOWNLOAD)) continue; /* don't bother, no need to retry yet */ if (routerset_contains_bridge(options->ExcludeNodes, bridge)) { download_status_mark_impossible(&bridge->fetch_status); log_warn(LD_APP, "Not using bridge at %s: it is in ExcludeNodes.", safe_str_client(fmt_and_decorate_addr(&bridge->addr))); continue; } /* schedule another fetch as if this one will fail, in case it does */ download_status_failed(&bridge->fetch_status, 0); can_use_bridge_authority = !tor_digest_is_zero(bridge->identity) && num_bridge_auths; ask_bridge_directly = !can_use_bridge_authority || !options->UpdateBridgesFromAuthority; log_debug(LD_DIR, "ask_bridge_directly=%d (%d, %d, %d)", ask_bridge_directly, tor_digest_is_zero(bridge->identity), !options->UpdateBridgesFromAuthority, !num_bridge_auths); if (ask_bridge_directly && !fascist_firewall_allows_address_addr(&bridge->addr, bridge->port, FIREWALL_OR_CONNECTION, 0, 0)) { log_notice(LD_DIR, "Bridge at '%s' isn't reachable by our " "firewall policy. %s.", fmt_addrport(&bridge->addr, bridge->port), can_use_bridge_authority ? "Asking bridge authority instead" : "Skipping"); if (can_use_bridge_authority) ask_bridge_directly = 0; else continue; } if (ask_bridge_directly) { /* we need to ask the bridge itself for its descriptor. */ launch_direct_bridge_descriptor_fetch(bridge); } else { /* We have a digest and we want to ask an authority. We could * combine all the requests into one, but that may give more * hints to the bridge authority than we want to give. */ char resource[10 + HEX_DIGEST_LEN]; memcpy(resource, "fp/", 3); base16_encode(resource+3, HEX_DIGEST_LEN+1, bridge->identity, DIGEST_LEN); memcpy(resource+3+HEX_DIGEST_LEN, ".z", 3); log_info(LD_DIR, "Fetching bridge info '%s' from bridge authority.", resource); directory_get_from_dirserver(DIR_PURPOSE_FETCH_SERVERDESC, ROUTER_PURPOSE_BRIDGE, resource, 0, DL_WANT_AUTHORITY); } } SMARTLIST_FOREACH_END(bridge); } /** If our bridge is configured to be a different address than * the bridge gives in node, rewrite the routerinfo * we received to use the address we meant to use. Now we handle * multihomed bridges better. */ static void rewrite_node_address_for_bridge(const bridge_info_t *bridge, node_t *node) { /* XXXX move this function. */ /* XXXX overridden addresses should really live in the node_t, so that the * routerinfo_t and the microdesc_t can be immutable. But we can only * do that safely if we know that no function that connects to an OR * does so through an address from any source other than node_get_addr(). */ tor_addr_t addr; const or_options_t *options = get_options(); if (node->ri) { routerinfo_t *ri = node->ri; tor_addr_from_ipv4h(&addr, ri->addr); if ((!tor_addr_compare(&bridge->addr, &addr, CMP_EXACT) && bridge->port == ri->or_port) || (!tor_addr_compare(&bridge->addr, &ri->ipv6_addr, CMP_EXACT) && bridge->port == ri->ipv6_orport)) { /* they match, so no need to do anything */ } else { if (tor_addr_family(&bridge->addr) == AF_INET) { ri->addr = tor_addr_to_ipv4h(&bridge->addr); ri->or_port = bridge->port; log_info(LD_DIR, "Adjusted bridge routerinfo for '%s' to match configured " "address %s:%d.", ri->nickname, fmt_addr32(ri->addr), ri->or_port); } else if (tor_addr_family(&bridge->addr) == AF_INET6) { tor_addr_copy(&ri->ipv6_addr, &bridge->addr); ri->ipv6_orport = bridge->port; log_info(LD_DIR, "Adjusted bridge routerinfo for '%s' to match configured " "address %s.", ri->nickname, fmt_addrport(&ri->ipv6_addr, ri->ipv6_orport)); } else { log_err(LD_BUG, "Address family not supported: %d.", tor_addr_family(&bridge->addr)); return; } } if (options->ClientPreferIPv6ORPort == -1) { /* Mark which address to use based on which bridge_t we got. */ node->ipv6_preferred = (tor_addr_family(&bridge->addr) == AF_INET6 && !tor_addr_is_null(&node->ri->ipv6_addr)); } else { /* Mark which address to use based on user preference */ node->ipv6_preferred = (fascist_firewall_prefer_ipv6_orport(options) && !tor_addr_is_null(&node->ri->ipv6_addr)); } /* XXXipv6 we lack support for falling back to another address for the same relay, warn the user */ if (!tor_addr_is_null(&ri->ipv6_addr)) { tor_addr_port_t ap; node_get_pref_orport(node, &ap); log_notice(LD_CONFIG, "Bridge '%s' has both an IPv4 and an IPv6 address. " "Will prefer using its %s address (%s) based on %s.", ri->nickname, node->ipv6_preferred ? "IPv6" : "IPv4", fmt_addrport(&ap.addr, ap.port), options->ClientPreferIPv6ORPort == -1 ? "the configured Bridge address" : "ClientPreferIPv6ORPort"); } } if (node->rs) { routerstatus_t *rs = node->rs; tor_addr_from_ipv4h(&addr, rs->addr); if (!tor_addr_compare(&bridge->addr, &addr, CMP_EXACT) && bridge->port == rs->or_port) { /* they match, so no need to do anything */ } else { rs->addr = tor_addr_to_ipv4h(&bridge->addr); rs->or_port = bridge->port; log_info(LD_DIR, "Adjusted bridge routerstatus for '%s' to match " "configured address %s.", rs->nickname, fmt_addrport(&bridge->addr, rs->or_port)); } } } /** We just learned a descriptor for a bridge. See if that * digest is in our entry guard list, and add it if not. */ void learned_bridge_descriptor(routerinfo_t *ri, int from_cache) { tor_assert(ri); tor_assert(ri->purpose == ROUTER_PURPOSE_BRIDGE); if (get_options()->UseBridges) { int first = num_bridges_usable() <= 1; bridge_info_t *bridge = get_configured_bridge_by_routerinfo(ri); time_t now = time(NULL); router_set_status(ri->cache_info.identity_digest, 1); if (bridge) { /* if we actually want to use this one */ node_t *node; /* it's here; schedule its re-fetch for a long time from now. */ if (!from_cache) download_status_reset(&bridge->fetch_status); node = node_get_mutable_by_id(ri->cache_info.identity_digest); tor_assert(node); rewrite_node_address_for_bridge(bridge, node); if (tor_digest_is_zero(bridge->identity)) { memcpy(bridge->identity,ri->cache_info.identity_digest, DIGEST_LEN); log_notice(LD_DIR, "Learned identity %s for bridge at %s:%d", hex_str(bridge->identity, DIGEST_LEN), fmt_and_decorate_addr(&bridge->addr), (int) bridge->port); } add_an_entry_guard(node, 1, 1, 0, 0); log_notice(LD_DIR, "new bridge descriptor '%s' (%s): %s", ri->nickname, from_cache ? "cached" : "fresh", router_describe(ri)); /* set entry->made_contact so if it goes down we don't drop it from * our entry node list */ entry_guard_register_connect_status(ri->cache_info.identity_digest, 1, 0, now); if (first) { routerlist_retry_directory_downloads(now); } } } } /** Return the number of bridges that have descriptors that * are marked with purpose 'bridge' and are running. * * We use this function to decide if we're ready to start building * circuits through our bridges, or if we need to wait until the * directory "server/authority" requests finish. */ int any_bridge_descriptors_known(void) { tor_assert(get_options()->UseBridges); return choose_random_entry(NULL) != NULL; } /** Return the number of bridges that have descriptors that are marked with * purpose 'bridge' and are running. */ static int num_bridges_usable(void) { int n_options = 0; tor_assert(get_options()->UseBridges); (void) choose_random_entry_impl(NULL, 0, 0, &n_options); return n_options; } /** Return a smartlist containing all bridge identity digests */ MOCK_IMPL(smartlist_t *, list_bridge_identities, (void)) { smartlist_t *result = NULL; char *digest_tmp; if (get_options()->UseBridges && bridge_list) { result = smartlist_new(); SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) { digest_tmp = tor_malloc(DIGEST_LEN); memcpy(digest_tmp, b->identity, DIGEST_LEN); smartlist_add(result, digest_tmp); } SMARTLIST_FOREACH_END(b); } return result; } /** Get the download status for a bridge descriptor given its identity */ MOCK_IMPL(download_status_t *, get_bridge_dl_status_by_id, (const char *digest)) { download_status_t *dl = NULL; if (digest && get_options()->UseBridges && bridge_list) { SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) { if (tor_memeq(digest, b->identity, DIGEST_LEN)) { dl = &(b->fetch_status); break; } } SMARTLIST_FOREACH_END(b); } return dl; } /** Return 1 if we have at least one descriptor for an entry guard * (bridge or member of EntryNodes) and all descriptors we know are * down. Else return 0. If act is 1, then mark the down guards * up; else just observe and report. */ static int entries_retry_helper(const or_options_t *options, int act) { const node_t *node; int any_known = 0; int any_running = 0; int need_bridges = options->UseBridges != 0; if (!entry_guards) entry_guards = smartlist_new(); SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { node = node_get_by_id(e->identity); if (node && node_has_descriptor(node) && node_is_bridge(node) == need_bridges && (!need_bridges || (!e->bad_since && node_is_a_configured_bridge(node)))) { any_known = 1; if (node->is_running) any_running = 1; /* some entry is both known and running */ else if (act) { /* Mark all current connections to this OR as unhealthy, since * otherwise there could be one that started 30 seconds * ago, and in 30 seconds it will time out, causing us to mark * the node down and undermine the retry attempt. We mark even * the established conns, since if the network just came back * we'll want to attach circuits to fresh conns. */ connection_or_set_bad_connections(node->identity, 1); /* mark this entry node for retry */ router_set_status(node->identity, 1); e->can_retry = 1; e->bad_since = 0; } } } SMARTLIST_FOREACH_END(e); log_debug(LD_DIR, "%d: any_known %d, any_running %d", act, any_known, any_running); return any_known && !any_running; } /** Do we know any descriptors for our bridges / entrynodes, and are * all the ones we have descriptors for down? */ int entries_known_but_down(const or_options_t *options) { tor_assert(entry_list_is_constrained(options)); return entries_retry_helper(options, 0); } /** Mark all down known bridges / entrynodes up. */ void entries_retry_all(const or_options_t *options) { tor_assert(entry_list_is_constrained(options)); entries_retry_helper(options, 1); } /** Return true if at least one of our bridges runs a Tor version that can * provide microdescriptors to us. If not, we'll fall back to asking for * full descriptors. */ int any_bridge_supports_microdescriptors(void) { const node_t *node; if (!get_options()->UseBridges || !entry_guards) return 0; SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) { node = node_get_by_id(e->identity); if (node && node->is_running && node_is_bridge(node) && node_is_a_configured_bridge(node)) { /* This is one of our current bridges, and we know enough about * it to know that it will be able to answer our questions. */ return 1; } } SMARTLIST_FOREACH_END(e); return 0; } /** Release all storage held by the list of entry guards and related * memory structs. */ void entry_guards_free_all(void) { if (entry_guards) { SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, entry_guard_free(e)); smartlist_free(entry_guards); entry_guards = NULL; } clear_bridge_list(); smartlist_free(bridge_list); bridge_list = NULL; circuit_build_times_free_timeouts(get_circuit_build_times_mutable()); }