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- /* 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 "bridges.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"
- /** All the context for guard selection on a particular client */
- struct guard_selection_s {
- /**
- * A value of 1 means that guard_selection_t structures have changed
- * and those changes need to be flushed to disk.
- *
- * XXX we don't know how to flush multiple guard contexts to disk yet;
- * fix that as soon as any way to change the default exists, or at least
- * make sure this gets set on change.
- */
- int dirty;
- /**
- * A list of the sampled entry guards, as entry_guard_t structures.
- * Not in any particular order. */
- smartlist_t *sampled_entry_guards;
- /**
- * A list of our chosen entry guards, as entry_guard_t structures; this
- * preserves the pre-Prop271 behavior.
- */
- smartlist_t *chosen_entry_guards;
- /**
- * When we try to choose an entry guard, should we parse and add
- * config's EntryNodes first? This was formerly a global.
- */
- int should_add_entry_nodes;
- int filtered_up_to_date;
- };
- static smartlist_t *guard_contexts = NULL;
- static guard_selection_t *curr_guard_context = NULL;
- static const node_t *choose_random_entry_impl(guard_selection_t *gs,
- cpath_build_state_t *state,
- int for_directory,
- dirinfo_type_t dirtype,
- int *n_options_out);
- static guard_selection_t * guard_selection_new(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
- /** Allocate a new guard_selection_t */
- static guard_selection_t *
- guard_selection_new(void)
- {
- guard_selection_t *gs;
- gs = tor_malloc_zero(sizeof(*gs));
- gs->chosen_entry_guards = smartlist_new();
- gs->sampled_entry_guards = smartlist_new();
- return gs;
- }
- /** Get current default guard_selection_t, creating it if necessary */
- guard_selection_t *
- get_guard_selection_info(void)
- {
- if (!guard_contexts) {
- guard_contexts = smartlist_new();
- }
- if (!curr_guard_context) {
- curr_guard_context = guard_selection_new();
- smartlist_add(guard_contexts, curr_guard_context);
- }
- return curr_guard_context;
- }
- /** Return the list of entry guards for a guard_selection_t, creating it
- * if necessary. */
- const smartlist_t *
- get_entry_guards_for_guard_selection(guard_selection_t *gs)
- {
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- return gs->chosen_entry_guards;
- }
- /** Return the list of entry guards for the default guard_selection_t,
- * creating it if necessary. */
- const smartlist_t *
- get_entry_guards(void)
- {
- return get_entry_guards_for_guard_selection(get_guard_selection_info());
- }
- /** Helper: mark an entry guard as not usable. */
- void
- entry_guard_mark_bad(entry_guard_t *guard)
- {
- guard->bad_since = approx_time();
- entry_guards_changed();
- }
- /** Return a statically allocated human-readable description of <b>guard</b>
- */
- const char *
- entry_guard_describe(const entry_guard_t *guard)
- {
- static char buf[256];
- tor_snprintf(buf, sizeof(buf),
- "%s ($%s)",
- guard->nickname, hex_str(guard->identity, DIGEST_LEN));
- return buf;
- }
- /** Return <b>guard</b>'s 20-byte RSA identity digest */
- const char *
- entry_guard_get_rsa_id_digest(const entry_guard_t *guard)
- {
- return guard->identity;
- }
- /** Return the pathbias state associated with <b>guard</b>. */
- guard_pathbias_t *
- entry_guard_get_pathbias_state(entry_guard_t *guard)
- {
- return &guard->pb;
- }
- /** Return an interval betweeen 'now' and 'max_backdate' seconds in the past,
- * chosen uniformly at random. */
- STATIC time_t
- randomize_time(time_t now, time_t max_backdate)
- {
- tor_assert(max_backdate > 0);
- time_t earliest = now - max_backdate;
- time_t latest = now;
- if (earliest <= 0)
- earliest = 1;
- if (latest <= earliest)
- latest = earliest + 1;
- return crypto_rand_time_range(earliest, latest);
- }
- /**
- * DOCDOC
- */
- STATIC void
- entry_guard_add_to_sample(guard_selection_t *gs,
- node_t *node)
- {
- (void) entry_guard_add_to_sample; // XXXX prop271 remove -- unused
- const int GUARD_LIFETIME = 90 * 86400; // xxxx prop271
- tor_assert(gs);
- tor_assert(node);
- // XXXX prop271 take ed25519 identity here too.
- /* make sure that the guard is not already sampled. */
- SMARTLIST_FOREACH_BEGIN(gs->sampled_entry_guards,
- entry_guard_t *, sampled) {
- if (BUG(tor_memeq(node->identity, sampled->identity, DIGEST_LEN))) {
- return;
- }
- } SMARTLIST_FOREACH_END(sampled);
- entry_guard_t *guard = tor_malloc_zero(sizeof(entry_guard_t));
- /* persistent fields */
- memcpy(guard->identity, node->identity, DIGEST_LEN);
- strlcpy(guard->nickname, node_get_nickname(node), sizeof(guard->nickname));
- guard->sampled_on_date = randomize_time(approx_time(), GUARD_LIFETIME/10);
- tor_free(guard->sampled_by_version);
- guard->sampled_by_version = tor_strdup(VERSION);
- guard->confirmed_idx = -1;
- /* non-persistent fields */
- guard->is_reachable = GUARD_REACHABLE_MAYBE;
- smartlist_add(gs->sampled_entry_guards, guard);
- gs->filtered_up_to_date = 0;
- entry_guards_changed_for_guard_selection(gs);
- }
- /**
- * Return a newly allocated string for encoding the persistent parts of
- * <b>guard</b> to the state file.
- */
- STATIC char *
- entry_guard_encode_for_state(entry_guard_t *guard)
- {
- /*
- * The meta-format we use is K=V K=V K=V... where K can be any
- * characters excepts space and =, and V can be any characters except
- * space. The order of entries is not allowed to matter.
- * Unrecognized K=V entries are persisted; recognized but erroneous
- * entries are corrected.
- */
- smartlist_t *result = smartlist_new();
- char tbuf[ISO_TIME_LEN+1];
- tor_assert(guard);
- smartlist_add_asprintf(result, "rsa_id=%s",
- hex_str(guard->identity, DIGEST_LEN));
- if (strlen(guard->nickname)) {
- smartlist_add_asprintf(result, "nickname=%s", guard->nickname);
- }
- format_iso_time_nospace(tbuf, guard->sampled_on_date);
- smartlist_add_asprintf(result, "sampled_on=%s", tbuf);
- if (guard->sampled_by_version) {
- smartlist_add_asprintf(result, "sampled_by=%s",
- guard->sampled_by_version);
- }
- if (guard->unlisted_since_date > 0) {
- format_iso_time_nospace(tbuf, guard->unlisted_since_date);
- smartlist_add_asprintf(result, "unlisted_since=%s", tbuf);
- }
- smartlist_add_asprintf(result, "listed=%d",
- (int)guard->currently_listed);
- if (guard->confirmed_idx >= 0) {
- format_iso_time_nospace(tbuf, guard->confirmed_on_date);
- smartlist_add_asprintf(result, "confirmed_on=%s", tbuf);
- smartlist_add_asprintf(result, "confirmed_idx=%d", guard->confirmed_idx);
- }
- if (guard->extra_state_fields)
- smartlist_add_strdup(result, guard->extra_state_fields);
- char *joined = smartlist_join_strings(result, " ", 0, NULL);
- SMARTLIST_FOREACH(result, char *, cp, tor_free(cp));
- smartlist_free(result);
- return joined;
- }
- /**
- * Given a string generated by entry_guard_encode_for_state(), parse it
- * (if possible) and return an entry_guard_t object for it. Return NULL
- * on complete failure.
- */
- STATIC entry_guard_t *
- entry_guard_parse_from_state(const char *s)
- {
- /* Unrecognized entries get put in here. */
- smartlist_t *extra = smartlist_new();
- /* These fields get parsed from the string. */
- char *rsa_id = NULL;
- char *nickname = NULL;
- char *sampled_on = NULL;
- char *sampled_by = NULL;
- char *unlisted_since = NULL;
- char *listed = NULL;
- char *confirmed_on = NULL;
- char *confirmed_idx = NULL;
- /* Split up the entries. Put the ones we know about in strings and the
- * rest in "extra". */
- {
- smartlist_t *entries = smartlist_new();
- strmap_t *vals = strmap_new(); // Maps keyword to location
- strmap_set(vals, "rsa_id", &rsa_id);
- strmap_set(vals, "nickname", &nickname);
- strmap_set(vals, "sampled_on", &sampled_on);
- strmap_set(vals, "sampled_by", &sampled_by);
- strmap_set(vals, "unlisted_since", &unlisted_since);
- strmap_set(vals, "listed", &listed);
- strmap_set(vals, "confirmed_on", &confirmed_on);
- strmap_set(vals, "confirmed_idx", &confirmed_idx);
- smartlist_split_string(entries, s, " ",
- SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
- SMARTLIST_FOREACH_BEGIN(entries, char *, entry) {
- const char *eq = strchr(entry, '=');
- if (!eq) {
- smartlist_add(extra, entry);
- continue;
- }
- char *key = tor_strndup(entry, eq-entry);
- char **target = strmap_get(vals, key);
- if (target == NULL || *target != NULL) {
- /* unrecognized or already set */
- smartlist_add(extra, entry);
- tor_free(key);
- continue;
- }
- *target = tor_strdup(eq+1);
- tor_free(key);
- tor_free(entry);
- } SMARTLIST_FOREACH_END(entry);
- smartlist_free(entries);
- strmap_free(vals, NULL);
- }
- entry_guard_t *guard = tor_malloc_zero(sizeof(entry_guard_t));
- if (rsa_id == NULL) {
- log_warn(LD_CIRC, "Guard missing RSA ID field");
- goto err;
- }
- /* Process the identity and nickname. */
- if (base16_decode(guard->identity, sizeof(guard->identity),
- rsa_id, strlen(rsa_id)) != DIGEST_LEN) {
- log_warn(LD_CIRC, "Unable to decode guard identity %s", escaped(rsa_id));
- goto err;
- }
- if (nickname) {
- strlcpy(guard->nickname, nickname, sizeof(guard->nickname));
- } else {
- guard->nickname[0]='$';
- base16_encode(guard->nickname+1, sizeof(guard->nickname)-1,
- guard->identity, DIGEST_LEN);
- }
- /* Process the various time fields. */
- #define HANDLE_TIME(field) do { \
- if (field) { \
- int r = parse_iso_time_nospace(field, &field ## _time); \
- if (r < 0) { \
- log_warn(LD_CIRC, "Unable to parse %s %s from guard", \
- #field, escaped(field)); \
- field##_time = -1; \
- } \
- } \
- } while (0)
- time_t sampled_on_time = 0;
- time_t unlisted_since_time = 0;
- time_t confirmed_on_time = 0;
- HANDLE_TIME(sampled_on);
- HANDLE_TIME(unlisted_since);
- HANDLE_TIME(confirmed_on);
- if (sampled_on_time <= 0)
- sampled_on_time = approx_time();
- if (unlisted_since_time < 0)
- unlisted_since_time = 0;
- if (confirmed_on_time < 0)
- confirmed_on_time = 0;
- #undef HANDLE_TIME
- guard->sampled_on_date = sampled_on_time;
- guard->unlisted_since_date = unlisted_since_time;
- guard->confirmed_on_date = confirmed_on_time;
- /* Take sampled_by_version verbatim. */
- guard->sampled_by_version = sampled_by;
- sampled_by = NULL; /* prevent free */
- /* Listed is a boolean */
- if (listed && strcmp(listed, "0"))
- guard->currently_listed = 1;
- /* The index is a nonnegative integer. */
- guard->confirmed_idx = -1;
- if (confirmed_idx) {
- int ok=1;
- long idx = tor_parse_long(confirmed_idx, 10, 0, INT_MAX, &ok, NULL);
- if (! ok) {
- log_warn(LD_CIRC, "Guard has invalid confirmed_idx %s",
- escaped(confirmed_idx));
- } else {
- guard->confirmed_idx = (int)idx;
- }
- }
- /* Anything we didn't recognize gets crammed together */
- if (smartlist_len(extra) > 0) {
- guard->extra_state_fields = smartlist_join_strings(extra, " ", 0, NULL);
- }
- /* initialize non-persistent fields */
- guard->is_reachable = GUARD_REACHABLE_MAYBE;
- goto done;
- err:
- // only consider it an error if the guard state was totally unparseable.
- entry_guard_free(guard);
- guard = NULL;
- done:
- tor_free(rsa_id);
- tor_free(nickname);
- tor_free(sampled_on);
- tor_free(sampled_by);
- tor_free(unlisted_since);
- tor_free(listed);
- tor_free(confirmed_on);
- tor_free(confirmed_idx);
- SMARTLIST_FOREACH(extra, char *, cp, tor_free(cp));
- smartlist_free(extra);
- return guard;
- }
- /** Check whether the entry guard <b>e</b> is usable, given the directory
- * authorities' opinion about the router (stored in <b>ri</b>) and the user's
- * configuration (in <b>options</b>). Set <b>e</b>->bad_since
- * accordingly. Return true iff the entry guard's status changes.
- *
- * If it's not usable, set *<b>reason</b> 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->pb.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 <b>e</b> 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 <b>e</b>, if <b>e</b> 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 <b>need_uptime</b> or <b>need_capacity</b>
- * (unless it's a configured EntryNode);
- * - Allowed by our current ReachableORAddresses config option; and
- * - Currently thought to be reachable by us (unless <b>assume_reachable</b>
- * is true).
- *
- * If the answer is no, set *<b>msg</b> 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->pb.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, in the
- * context of the given guard_selection_t */
- int
- num_live_entry_guards_for_guard_selection(guard_selection_t *gs,
- int for_directory)
- {
- int n = 0;
- const char *msg;
- tor_assert(gs != NULL);
- /* 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 (!(gs->chosen_entry_guards)) {
- return 0;
- }
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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;
- }
- /** Return the number of entry guards that we think are usable, for the
- * default guard selection */
- int
- num_live_entry_guards(int for_directory)
- {
- return num_live_entry_guards_for_guard_selection(
- get_guard_selection_info(), for_directory);
- }
- /** If <b>digest</b> matches the identity of any node in the
- * entry_guards list for the provided guard selection state,
- return that node. Else return NULL. */
- entry_guard_t *
- entry_guard_get_by_id_digest_for_guard_selection(guard_selection_t *gs,
- const char *digest)
- {
- tor_assert(gs != NULL);
- SMARTLIST_FOREACH(gs->chosen_entry_guards, entry_guard_t *, entry,
- if (tor_memeq(digest, entry->identity, DIGEST_LEN))
- return entry;
- );
- return NULL;
- }
- /** Return the node_t associated with a single entry_guard_t. May
- * return NULL if the guard is not currently in the consensus. */
- const node_t *
- entry_guard_find_node(const entry_guard_t *guard)
- {
- tor_assert(guard);
- return node_get_by_id(guard->identity);
- }
- /** If <b>digest</b> matches the identity of any node in the
- * entry_guards list for the default guard selection state,
- return that node. Else return NULL. */
- entry_guard_t *
- entry_guard_get_by_id_digest(const char *digest)
- {
- return entry_guard_get_by_id_digest_for_guard_selection(
- get_guard_selection_info(), digest);
- }
- /** Dump a description of our list of entry guards in the given guard
- * selection context to the log at level <b>severity</b>. */
- static void
- log_entry_guards_for_guard_selection(guard_selection_t *gs, int severity)
- {
- smartlist_t *elements = smartlist_new();
- char *s;
- /*
- * TODO this should probably log more info about prop-271 state too
- * when it's implemented.
- */
- tor_assert(gs != NULL);
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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 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.
- *
- * If <b>chosen</b> 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(guard_selection_t *gs,
- const node_t *chosen, int reset_status, int prepend,
- int for_discovery, int for_directory)
- {
- const node_t *node;
- entry_guard_t *entry;
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- if (chosen) {
- node = chosen;
- entry = entry_guard_get_by_id_digest_for_guard_selection(gs,
- 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 (entry_guard_get_by_id_digest_for_guard_selection(gs, 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. */
- 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;
- if (prepend)
- smartlist_insert(gs->chosen_entry_guards, 0, entry);
- else
- smartlist_add(gs->chosen_entry_guards, entry);
- control_event_guard(entry->nickname, entry->identity, "NEW");
- control_event_guard_deferred();
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- return node;
- }
- /** Entry point for bridges.c to add a bridge as guard.
- *
- * XXXX prop271 refactor.*/
- void
- add_bridge_as_entry_guard(guard_selection_t *gs,
- const node_t *chosen)
- {
- 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)
- {
- 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(guard_selection_t *gs,
- const or_options_t *options,
- int for_directory)
- {
- int changed = 0;
- const int num_needed = decide_num_guards(options, for_directory);
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- while (num_live_entry_guards_for_guard_selection(gs, for_directory)
- < num_needed) {
- if (!add_an_entry_guard(gs, NULL, 0, 0, 0, for_directory))
- break;
- changed = 1;
- }
- if (changed)
- 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)
- {
- if (!e)
- return;
- tor_free(e->chosen_by_version);
- tor_free(e->sampled_by_version);
- tor_free(e->extra_state_fields);
- 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
- * months ago. */
- /* XXXX The "obsolete guards" and "chosen long ago guards" things should
- * probably be different functions. */
- static int
- remove_obsolete_entry_guards(guard_selection_t *gs, time_t now)
- {
- int changed = 0, i;
- int32_t guard_lifetime = guards_get_lifetime();
- tor_assert(gs != NULL);
- if (!(gs->chosen_entry_guards)) goto done;
- for (i = 0; i < smartlist_len(gs->chosen_entry_guards); ++i) {
- entry_guard_t *entry = smartlist_get(gs->chosen_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(gs->chosen_entry_guards, i--);
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- changed = 1;
- }
- }
- done:
- return changed ? 1 : 0;
- }
- /** Remove all entry guards from this guard selection context 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(guard_selection_t *gs, time_t now)
- {
- char dbuf[HEX_DIGEST_LEN+1];
- char tbuf[ISO_TIME_LEN+1];
- int i;
- int changed = 0;
- tor_assert(gs != NULL);
- if (!(gs->chosen_entry_guards)) goto done;
- for (i = 0; i < smartlist_len(gs->chosen_entry_guards); ) {
- entry_guard_t *entry = smartlist_get(gs->chosen_entry_guards, i);
- if (entry->bad_since &&
- ! entry->pb.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(gs->chosen_entry_guards, i);
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- changed = 1;
- } else
- ++i;
- }
- done:
- return changed ? 1 : 0;
- }
- /** Remove all currently listed entry guards for a given guard selection
- * context */
- void
- remove_all_entry_guards_for_guard_selection(guard_selection_t *gs)
- {
- char dbuf[HEX_DIGEST_LEN+1];
- tor_assert(gs != NULL);
- if (gs->chosen_entry_guards) {
- while (smartlist_len(gs->chosen_entry_guards)) {
- entry_guard_t *entry = smartlist_get(gs->chosen_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(gs->chosen_entry_guards, 0);
- }
- }
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- entry_guards_changed_for_guard_selection(gs);
- }
- /** Remove all currently listed entry guards. So new ones will be chosen. */
- void
- remove_all_entry_guards(void)
- {
- remove_all_entry_guards_for_guard_selection(get_guard_selection_info());
- }
- /** 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_for_guard_selection(guard_selection_t *gs,
- const or_options_t *options,
- time_t now)
- {
- int changed = 0;
- digestmap_t *reasons;
- if ((!gs) || !(gs->chosen_entry_guards))
- return;
- if (options->EntryNodes) /* reshuffle the entry guard list if needed */
- entry_nodes_should_be_added();
- reasons = digestmap_new();
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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(gs, now))
- changed = 1;
- if (remove_obsolete_entry_guards(gs, now))
- changed = 1;
- if (changed) {
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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_for_guard_selection(gs, 0),
- smartlist_len(gs->chosen_entry_guards));
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- entry_guards_changed_for_guard_selection(gs);
- }
- digestmap_free(reasons, NULL);
- }
- /** 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)
- {
- entry_guards_compute_status_for_guard_selection(get_guard_selection_info(),
- options, now);
- }
- /** Called when a connection to an OR with the identity digest <b>digest</b>
- * is established (<b>succeeded</b>==1) or has failed (<b>succeeded</b>==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 <b>mark_relay_status</b>, 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_for_guard_selection(
- guard_selection_t *gs, 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 (!(gs) || !(gs->chosen_entry_guards)) {
- return 0;
- }
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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_for_guard_selection(gs, 0) - 1,
- smartlist_len(gs->chosen_entry_guards)-1);
- control_event_guard(entry->nickname, entry->identity, "DROPPED");
- entry_guard_free(entry);
- smartlist_del_keeporder(gs->chosen_entry_guards, idx);
- log_entry_guards_for_guard_selection(gs, 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(gs->chosen_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_for_guard_selection(gs, 0),
- smartlist_len(gs->chosen_entry_guards));
- log_entry_guards_for_guard_selection(gs, LOG_INFO);
- changed = 1;
- }
- }
- if (changed)
- entry_guards_changed_for_guard_selection(gs);
- return refuse_conn ? -1 : 0;
- }
- /** Called when a connection to an OR with the identity digest <b>digest</b>
- * is established (<b>succeeded</b>==1) or has failed (<b>succeeded</b>==0).
- * If the OR is an entry, change that entry's up/down status in the default
- * guard selection context.
- * Return 0 normally, or -1 if we want to tear down the new connection.
- *
- * If <b>mark_relay_status</b>, also call router_set_status() on this
- * relay.
- */
- int
- entry_guard_register_connect_status(const char *digest, int succeeded,
- int mark_relay_status, time_t now)
- {
- return entry_guard_register_connect_status_for_guard_selection(
- get_guard_selection_info(), digest, succeeded, mark_relay_status, now);
- }
- /** Called when the value of EntryNodes changes in our configuration. */
- void
- entry_nodes_should_be_added_for_guard_selection(guard_selection_t *gs)
- {
- tor_assert(gs != NULL);
- log_info(LD_CIRC, "EntryNodes config option set. Putting configured "
- "relays at the front of the entry guard list.");
- gs->should_add_entry_nodes = 1;
- }
- /** Called when the value of EntryNodes changes in our configuration. */
- void
- entry_nodes_should_be_added(void)
- {
- entry_nodes_should_be_added_for_guard_selection(
- get_guard_selection_info());
- }
- /** 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(guard_selection_t *gs,
- 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(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- gs->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(gs->chosen_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_for_guard_selection(gs,
- 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(gs->chosen_entry_guards);
- /* First, the previously configured guards that are in EntryNodes. */
- smartlist_add_all(gs->chosen_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(gs, node, 0, 0, 1, 0);
- if (smartlist_len(gs->chosen_entry_guards) > numentryguards * 10)
- break;
- } SMARTLIST_FOREACH_END(node);
- log_notice(LD_GENERAL, "%d entries in guards",
- smartlist_len(gs->chosen_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));
- 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_for_guard_selection(gs);
- }
- /** 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
- * <b>state</b> 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 <b>state</b> is NULL, we're looking for a random
- * guard (likely a bridge). If <b>dirinfo</b> 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(get_guard_selection_info(),
- state, 0, NO_DIRINFO, NULL);
- }
- /** Pick a live (up and listed) directory guard from entry_guards for
- * downloading information of type <b>type</b>. */
- const node_t *
- choose_random_dirguard(dirinfo_type_t type)
- {
- return choose_random_entry_impl(get_guard_selection_info(),
- NULL, 1, type, NULL);
- }
- /** Return the number of bridges that have descriptors that are marked with
- * purpose 'bridge' and are running.
- */
- int
- num_bridges_usable(void)
- {
- int n_options = 0;
- tor_assert(get_options()->UseBridges);
- (void) choose_random_entry_impl(get_guard_selection_info(),
- NULL, 0, 0, &n_options);
- return n_options;
- }
- /** Filter <b>all_entry_guards</b> for usable entry guards and put them
- * in <b>live_entry_guards</b>. 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 <b>live_entry_guards</b>.
- *
- * If <b>chosen_exit</b> is set, it contains the exit node of this
- * circuit. Make sure to not use it or its family as an entry guard.
- *
- * If <b>need_uptime</b> is set, we are looking for a stable entry guard.
- * if <b>need_capacity</b> 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, relative to
- * a supplied guard selection context.
- *
- * If <b>state</b> is set, it contains the information we know about
- * the upcoming circuit.
- *
- * If <b>for_directory</b> is set, we are looking for a directory guard.
- *
- * <b>dirinfo_type</b> 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 <b>dirinfo_type</b> filter is ignored).
- *
- * If <b>n_options_out</b> 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(guard_selection_t *gs,
- 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;
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- if (n_options_out)
- *n_options_out = 0;
- if (gs->should_add_entry_nodes)
- entry_guards_set_from_config(gs, options);
- if (!entry_list_is_constrained(options) &&
- smartlist_len(gs->chosen_entry_guards) < num_needed)
- pick_entry_guards(gs, 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,
- gs->chosen_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(gs, NULL, 0, 0, 1, for_directory);
- if (node) {
- entry_guards_changed_for_guard_selection(gs);
- /* 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 <b>state</b> and learn about the entry guards it describes.
- * If <b>set</b> is true, and there are no errors, replace the guard
- * list in the provided guard selection context with what we find.
- * On success, return 0. On failure, alloc into *<b>msg</b> a string
- * describing the error, and return -1.
- */
- int
- entry_guards_parse_state_for_guard_selection(
- guard_selection_t *gs,
- 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();
- if (0) entry_guard_parse_from_state(NULL); // XXXX prop271 remove -- unused
- if (0) entry_guard_add_to_sample(NULL, NULL); // XXXX prop271 remove
- tor_assert(gs != NULL);
- *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)<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->pb.use_attempts = use_cnt;
- node->pb.use_successes = success_cnt;
- log_info(LD_GENERAL, "Read %f/%f path use bias for node %s",
- node->pb.use_successes, node->pb.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->pb.use_attempts
- < pathbias_get_extreme_use_rate(options) &&
- pathbias_get_dropguards(options)) {
- node->pb.path_bias_disabled = 1;
- log_info(LD_GENERAL,
- "Path use bias is too high (%f/%f); disabling node %s",
- node->pb.circ_successes, node->pb.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->pb.circ_attempts = hop_cnt;
- node->pb.circ_successes = success_cnt;
- node->pb.successful_circuits_closed = successful_closed;
- node->pb.timeouts = timeouts;
- node->pb.collapsed_circuits = collapsed;
- node->pb.unusable_circuits = unusable;
- log_info(LD_GENERAL, "Read %f/%f path bias for node %s",
- node->pb.circ_successes, node->pb.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->pb.circ_attempts
- < pathbias_get_extreme_rate(options) &&
- pathbias_get_dropguards(options)) {
- node->pb.path_bias_disabled = 1;
- log_info(LD_GENERAL,
- "Path bias is too high (%f/%f); disabling node %s",
- node->pb.circ_successes, node->pb.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->pb.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 (gs->chosen_entry_guards) {
- SMARTLIST_FOREACH(gs->chosen_entry_guards, entry_guard_t *, e,
- entry_guard_free(e));
- smartlist_free(gs->chosen_entry_guards);
- }
- gs->chosen_entry_guards = new_entry_guards;
- gs->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(gs, now))
- gs->dirty = 1;
- }
- digestmap_free(added_by, tor_free_);
- return *msg ? -1 : 0;
- }
- /** Parse <b>state</b> and learn about the entry guards it describes.
- * If <b>set</b> is true, and there are no errors, replace the guard
- * list in the default guard selection context with what we find.
- * On success, return 0. On failure, alloc into *<b>msg</b> a string
- * describing the error, and return -1.
- */
- int
- entry_guards_parse_state(or_state_t *state, int set, char **msg)
- {
- return entry_guards_parse_state_for_guard_selection(
- get_guard_selection_info(),
- state, set, msg);
- }
- /** 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 for a particular guard selection
- * context, or some element of one of our entry guards has changed for one.
- * Write the changes to disk within the next few minutes.
- */
- void
- entry_guards_changed_for_guard_selection(guard_selection_t *gs)
- {
- time_t when;
- tor_assert(gs != NULL);
- gs->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);
- }
- /** Our list of entry guards has changed for the default guard selection
- * context, 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)
- {
- entry_guards_changed_for_guard_selection(get_guard_selection_info());
- }
- /** If the entry guard info has not changed, do nothing and return.
- * Otherwise, free the EntryGuards piece of <b>state</b> and create
- * a new one out of the global entry_guards list, and then mark
- * <b>state</b> dirty so it will get saved to disk.
- *
- * XXX this should get totally redesigned around storing multiple
- * entry guard contexts. For the initial refactor we'll just
- * always use the current default. Fix it as soon as we actually
- * have any way that default can change.
- */
- void
- entry_guards_update_state(or_state_t *state)
- {
- config_line_t **next, *line;
- guard_selection_t *gs = get_guard_selection_info();
- if (0) entry_guard_encode_for_state(NULL); // XXXX prop271 remove -- unused
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- if (!gs->dirty)
- return;
- config_free_lines(state->EntryGuards);
- next = &state->EntryGuards;
- *next = NULL;
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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->pb.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->pb.circ_attempts, e->pb.circ_successes,
- pathbias_get_close_success_count(e),
- e->pb.collapsed_circuits,
- e->pb.unusable_circuits, e->pb.timeouts);
- next = &(line->next);
- }
- if (e->pb.use_attempts > 0) {
- *next = line = tor_malloc_zero(sizeof(config_line_t));
- line->key = tor_strdup("EntryGuardPathUseBias");
- tor_asprintf(&line->value, "%f %f",
- e->pb.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);
- gs->dirty = 0;
- }
- /** If <b>question</b> is the string "entry-guards", then dump
- * to *<b>answer</b> 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".
- *
- * XXX this should be totally redesigned after prop 271 too, and that's
- * going to take some control spec work.
- * */
- int
- getinfo_helper_entry_guards(control_connection_t *conn,
- const char *question, char **answer,
- const char **errmsg)
- {
- guard_selection_t *gs = get_guard_selection_info();
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- (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];
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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
- * <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.
- *
- * 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 <b>guardfraction_bw</b> structure. It sets
- * <b>guard_bw</b> to F*B and <b>non_guard_bw</b> 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;
- }
- /** Returns true iff the node is used as a guard in the specified guard
- * context */
- int
- is_node_used_as_guard_for_guard_selection(guard_selection_t *gs,
- const node_t *node)
- {
- int res = 0;
- /*
- * We used to have a using_as_guard flag in node_t, but it had to go away
- * to allow for multiple guard selection contexts. Instead, search the
- * guard list for a matching digest.
- */
- tor_assert(gs != NULL);
- tor_assert(node != NULL);
- SMARTLIST_FOREACH_BEGIN(gs->chosen_entry_guards, entry_guard_t *, e) {
- if (tor_memeq(e->identity, node->identity, DIGEST_LEN)) {
- res = 1;
- break;
- }
- } SMARTLIST_FOREACH_END(e);
- return res;
- }
- /** Returns true iff the node is used as a guard in the default guard
- * context */
- MOCK_IMPL(int,
- is_node_used_as_guard, (const node_t *node))
- {
- return is_node_used_as_guard_for_guard_selection(
- get_guard_selection_info(), node);
- }
- /** 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 <b>act</b> 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;
- guard_selection_t *gs = get_guard_selection_info();
- tor_assert(gs != NULL);
- tor_assert(gs->chosen_entry_guards != NULL);
- SMARTLIST_FOREACH_BEGIN(gs->chosen_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);
- }
- /** Free one guard selection context */
- static void
- guard_selection_free(guard_selection_t *gs)
- {
- if (!gs) return;
- if (gs->chosen_entry_guards) {
- SMARTLIST_FOREACH(gs->chosen_entry_guards, entry_guard_t *, e,
- entry_guard_free(e));
- smartlist_free(gs->chosen_entry_guards);
- gs->chosen_entry_guards = NULL;
- }
- if (gs->sampled_entry_guards) {
- SMARTLIST_FOREACH(gs->sampled_entry_guards, entry_guard_t *, e,
- entry_guard_free(e));
- smartlist_free(gs->sampled_entry_guards);
- gs->sampled_entry_guards = NULL;
- }
- tor_free(gs);
- }
- /** Release all storage held by the list of entry guards and related
- * memory structs. */
- void
- entry_guards_free_all(void)
- {
- /* Null out the default */
- curr_guard_context = NULL;
- /* Free all the guard contexts */
- if (guard_contexts != NULL) {
- SMARTLIST_FOREACH_BEGIN(guard_contexts, guard_selection_t *, gs) {
- guard_selection_free(gs);
- } SMARTLIST_FOREACH_END(gs);
- smartlist_free(guard_contexts);
- guard_contexts = NULL;
- }
- circuit_build_times_free_timeouts(get_circuit_build_times_mutable());
- }
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