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https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-11-10 21:23:58 +01:00
first cut of the new helper stuff. seems to work in the normal
case, but many edge cases still need testing. svn:r5663
This commit is contained in:
Roger Dingledine
parent
9ef54a3d0c
commit
25052c6f4b
@ -48,10 +48,7 @@ static int onion_extend_cpath(uint8_t purpose, crypt_path_t **head_ptr,
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cpath_build_state_t *state);
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static int count_acceptable_routers(smartlist_t *routers);
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static int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
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static void pick_helper_nodes(void);
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static routerinfo_t *choose_random_helper(routerinfo_t *chosen_exit);
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static void clear_helper_nodes(void);
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static void remove_dead_helpers(void);
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static routerinfo_t *choose_random_helper(cpath_build_state_t *state);
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static void helper_nodes_changed(void);
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/** Iterate over values of circ_id, starting from conn-\>next_circ_id,
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@ -1508,7 +1505,7 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state)
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if (state && options->UseHelperNodes &&
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purpose != CIRCUIT_PURPOSE_TESTING) {
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return choose_random_helper(build_state_get_exit_router(state));
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return choose_random_helper(state);
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}
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if (state && (r = build_state_get_exit_router(state))) {
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@ -1698,6 +1695,31 @@ build_state_get_exit_nickname(cpath_build_state_t *state)
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return state->chosen_exit->nickname;
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}
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/** Return the router corresponding to <b>h</b>, if <b>h</b> is
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* working well enough that we are willing to use it as a helper
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* right now. (Else return NULL.) In particular, it must be
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* - Listed as either up or never yet contacted;
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* - Present in the routerlist;
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* - Listed as 'fast' by the current dirserver concensus; and
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* - Allowed by our current ReachableAddresses config option.
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*/
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static INLINE routerinfo_t *
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helper_is_live(helper_node_t *h, int need_uptime, int need_capacity)
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{
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routerinfo_t *r;
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if (h->down_since && h->made_contact)
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return NULL;
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r = router_get_by_digest(h->identity);
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if (!r)
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return NULL;
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if (router_is_unreliable(r, need_uptime, need_capacity))
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return NULL;
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if (firewall_is_fascist() &&
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!fascist_firewall_allows_address(r->addr,r->or_port))
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return NULL;
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return r;
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}
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/** Return the number of helper nodes that we think are usable. */
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static int
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num_live_helpers(void)
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@ -1706,11 +1728,55 @@ num_live_helpers(void)
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if (! helper_nodes)
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return 0;
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
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if (! helper->down_since && ! helper->unlisted_since)
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++n;);
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{
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if (helper_is_live(helper, 0, 1))
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++n;
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});
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return n;
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}
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/** Return 1 if <b>digest</b> matches the identity of any entry
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* in the helper_nodes list. Else return 0. */
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static INLINE int
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is_a_helper(char *digest)
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{
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
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if(!memcmp(digest, helper->identity, DIGEST_LEN))
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return 1;
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);
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return 0;
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}
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#define NUM_HELPER_PICK_TRIES 100
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/** Add a new (preferably stable and fast) helper to the end of our
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* helper_nodes list. Return a pointer to the router if we succeed,
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* or NULL if we can't find any more suitable helpers. If
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* <b>tries_left</b> is <= 1, that means you should fail. */
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static routerinfo_t *
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add_a_helper(int tries_left)
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{
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routerinfo_t *entry;
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helper_node_t *helper;
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if (--tries_left <= 0) {
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warn(LD_CIRC, "Tried finding a new helper, but failed. Bad news. XXX.");
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return NULL;
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}
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entry = choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
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if (!entry)
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return NULL;
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/* make sure it's not already a helper */
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if (is_a_helper(entry->cache_info.identity_digest))
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return add_a_helper(tries_left); /* recurse */
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helper = tor_malloc_zero(sizeof(helper_node_t));
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/* XXXX Downgrade this to info before release. NM */
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notice(LD_CIRC, "Chose '%s' as new helper node.", entry->nickname);
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strlcpy(helper->nickname, entry->nickname, sizeof(helper->nickname));
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memcpy(helper->identity, entry->cache_info.identity_digest, DIGEST_LEN);
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smartlist_add(helper_nodes, helper);
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return entry;
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}
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/** If the use of helper nodes is configured, choose more helper nodes
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* until we have enough in the list. */
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static void
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@ -1719,43 +1785,22 @@ pick_helper_nodes(void)
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or_options_t *options = get_options();
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int changed = 0;
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if (! options->UseHelperNodes)
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return;
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if (!helper_nodes)
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helper_nodes = smartlist_create();
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while (smartlist_len(helper_nodes) < options->NumHelperNodes) {
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routerinfo_t *entry =
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choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
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/* XXXX deal with duplicate entries. NM */
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helper_node_t *helper = tor_malloc_zero(sizeof(helper_node_t));
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/* XXXX Downgrade this to info before release. NM */
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notice(LD_CIRC, "Chose '%s' as helper node.", entry->nickname);
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strlcpy(helper->nickname, entry->nickname, sizeof(helper->nickname));
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memcpy(helper->identity, entry->cache_info.identity_digest, DIGEST_LEN);
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smartlist_add(helper_nodes, helper);
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while (num_live_helpers() < options->NumHelperNodes) {
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if (!add_a_helper(NUM_HELPER_PICK_TRIES))
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break;
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changed = 1;
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}
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if (changed)
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helper_nodes_changed();
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}
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/** Remove all elements from the list of helper nodes. */
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static void
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clear_helper_nodes(void)
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{
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
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smartlist_clear(helper_nodes);
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helper_nodes_changed();
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}
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/** Release all storage held by the list of helper nodes. */
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void
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helper_nodes_free_all(void)
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{
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/* Don't call clear_helper_nodes(); that will flush our state change to
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* disk. */
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if (helper_nodes) {
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
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smartlist_free(helper_nodes);
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@ -1763,16 +1808,19 @@ helper_nodes_free_all(void)
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}
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}
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/* XXX These are 12 hours for now, but I'd like to make them 30 days */
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/** How long (in seconds) do we allow a helper node to be nonfunctional
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* before we give up on it? */
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#define HELPER_ALLOW_DOWNTIME 48*60*60
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#define HELPER_ALLOW_DOWNTIME (1*12*60*60)
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/** How long (in seconds) do we allow a helper node to be unlisted in the
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* directory before we give up on it? */
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#define HELPER_ALLOW_UNLISTED 48*60*60
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#define HELPER_ALLOW_UNLISTED (1*12*60*60)
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/** Remove all helper nodes that have been down or unlisted for so
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* long that we don't think they'll come up again. */
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static void
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* long that we don't think they'll come up again. Return 1 if we
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* removed any, or 0 if we did nothing. */
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static int
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remove_dead_helpers(void)
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{
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char dbuf[HEX_DIGEST_LEN+1];
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@ -1800,13 +1848,12 @@ remove_dead_helpers(void)
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warn(LD_CIRC, "Helper node '%s' (%s) has been %s since %s; removing.",
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helper->nickname, dbuf, why, tbuf);
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tor_free(helper);
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smartlist_del(helper_nodes, i);
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smartlist_del_keeporder(helper_nodes, i);
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changed = 1;
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} else
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++i;
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}
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if (changed)
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helper_nodes_changed();
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return changed ? 1 : 0;
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}
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/** A new directory or router-status has arrived; update the down/listed
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@ -1870,14 +1917,14 @@ helper_nodes_set_status_from_directory(void)
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}
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});
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if (remove_dead_helpers())
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changed = 1;
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if (changed) {
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log_fn(severity, LD_CIRC, " (%d/%d helpers are usable)",
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num_live_helpers(), smartlist_len(helper_nodes));
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helper_nodes_changed();
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}
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remove_dead_helpers();
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pick_helper_nodes();
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}
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/** Called when a connection to an OR with the identity digest <b>digest</b>
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@ -1911,13 +1958,20 @@ helper_node_set_status(const char *digest, int succeeded)
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}
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} else {
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if (!helper->made_contact) { /* dump him */
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notice(LD_CIRC,
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"Connection to never-contacted helper node '%s' failed. "
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"Removing from the list. %d/%d helpers usable.",
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helper->nickname,
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num_live_helpers(), smartlist_len(helper_nodes));
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tor_free(helper);
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smartlist_del_keeporder(helper_nodes, helper_sl_idx);
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changed = 1;
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} else if (!helper->down_since) {
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helper->down_since = time(NULL);
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warn(LD_CIRC, "Connection to helper node '%s' failed."
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" %d/%d helpers usable.",
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helper->nickname, num_live_helpers(),
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smartlist_len(helper_nodes));
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helper->nickname,
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num_live_helpers(), smartlist_len(helper_nodes));
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changed = 1;
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}
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}
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@ -1928,32 +1982,55 @@ helper_node_set_status(const char *digest, int succeeded)
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helper_nodes_changed();
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}
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/** Pick a live (up and listed) helper node from the list of helpers, but
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* don't pick <b>exit</b>. If no helpers are available, pick a new list. */
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/** Pick a live (up and listed) helper node from the list of helpers, and
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* make sure not to pick this circuit's exit. */
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static routerinfo_t *
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choose_random_helper(routerinfo_t *chosen_exit)
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choose_random_helper(cpath_build_state_t *state)
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{
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smartlist_t *live_helpers = smartlist_create();
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routerinfo_t *chosen_exit = build_state_get_exit_router(state);
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routerinfo_t *r;
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int need_uptime = state->need_uptime;
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int need_capacity = state->need_capacity;
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if (! helper_nodes)
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if (! helper_nodes ||
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smartlist_len(helper_nodes) < get_options()->NumHelperNodes)
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pick_helper_nodes();
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retry:
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smartlist_clear(live_helpers);
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, helper,
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if (! helper->down_since && ! helper->unlisted_since) {
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if ((r = router_get_by_digest(helper->identity))) {
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if (r != chosen_exit)
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smartlist_add(live_helpers, r);
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}
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});
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{
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r = helper_is_live(helper, need_uptime, need_capacity);
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if (r && r != chosen_exit) {
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smartlist_add(live_helpers, r);
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if (smartlist_len(live_helpers) >= get_options()->NumHelperNodes)
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break; /* we have enough */
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}
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});
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if (! smartlist_len(live_helpers)) {
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/* XXXX Is this right? What if network is down? */
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warn(LD_CIRC, "No functional helper nodes found; picking a new set.");
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clear_helper_nodes();
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pick_helper_nodes();
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goto retry;
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/* Try to have at least 2 choices available. This way we don't
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* get stuck with a single live-but-crummy helper and just keep
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* using him.
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* (We might get 2 live-but-crummy helpers, but so be it.) */
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if (smartlist_len(live_helpers) < 2) {
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if (need_uptime) {
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need_uptime = 0; /* try without that requirement */
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goto retry;
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}
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/* still no? try adding a new helper then */
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r = add_a_helper(NUM_HELPER_PICK_TRIES);
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if (r) {
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smartlist_add(live_helpers, r);
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helper_nodes_changed();
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} else {
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if (need_capacity) {
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/* still no? last attempt, try without requiring capacity */
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need_capacity = 0;
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goto retry;
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}
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/* live_helpers will be empty below. Oh well, we tried. */
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}
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}
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r = smartlist_choose(live_helpers);
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@ -1971,7 +2048,7 @@ int
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helper_nodes_parse_state(or_state_t *state, int set, const char **err)
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{
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helper_node_t *node = NULL;
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smartlist_t *helpers = smartlist_create();
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smartlist_t *new_helpers = smartlist_create();
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config_line_t *line;
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*err = NULL;
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@ -1980,7 +2057,7 @@ helper_nodes_parse_state(or_state_t *state, int set, const char **err)
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smartlist_t *args = smartlist_create();
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node = tor_malloc_zero(sizeof(helper_node_t));
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node->made_contact = 1; /* all helpers on disk have been contacted */
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smartlist_add(helpers, node);
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smartlist_add(new_helpers, node);
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smartlist_split_string(args, line->value, " ",
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SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
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if (smartlist_len(args)<2) {
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@ -2016,16 +2093,14 @@ helper_nodes_parse_state(or_state_t *state, int set, const char **err)
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}
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if (*err || !set) {
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SMARTLIST_FOREACH(helpers, helper_node_t *, h, tor_free(h));
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smartlist_free(helpers);
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helpers = NULL;
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}
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if (!*err && set) {
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SMARTLIST_FOREACH(new_helpers, helper_node_t *, h, tor_free(h));
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smartlist_free(new_helpers);
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} else { /* !*err && set */
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if (helper_nodes) {
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SMARTLIST_FOREACH(helper_nodes, helper_node_t *, h, tor_free(h));
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smartlist_free(helper_nodes);
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}
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helper_nodes = helpers;
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helper_nodes = new_helpers;
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helper_nodes_dirty = 0;
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}
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return *err ? -1 : 0;
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