/* Copyright (c) 2001 Matej Pfajfar. * Copyright (c) 2001-2004, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. * Copyright (c) 2007-2013, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** * \file circuituse.c * \brief Launch the right sort of circuits and attach streams to them. **/ #include "or.h" #include "addressmap.h" #include "channel.h" #include "circpathbias.h" #include "circuitbuild.h" #include "circuitlist.h" #include "circuitstats.h" #include "circuituse.h" #include "config.h" #include "connection.h" #include "connection_edge.h" #include "control.h" #include "entrynodes.h" #include "nodelist.h" #include "networkstatus.h" #include "policies.h" #include "rendclient.h" #include "rendcommon.h" #include "rendservice.h" #include "rephist.h" #include "router.h" #include "routerlist.h" static void circuit_expire_old_circuits_clientside(void); static void circuit_increment_failure_count(void); /** Return 1 if circ could be returned by circuit_get_best(). * Else return 0. */ static int circuit_is_acceptable(const origin_circuit_t *origin_circ, const entry_connection_t *conn, int must_be_open, uint8_t purpose, int need_uptime, int need_internal, time_t now) { const circuit_t *circ = TO_CIRCUIT(origin_circ); const node_t *exitnode; cpath_build_state_t *build_state; tor_assert(circ); tor_assert(conn); tor_assert(conn->socks_request); if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_chan)) return 0; /* ignore non-open circs */ if (circ->marked_for_close) return 0; /* if this circ isn't our purpose, skip. */ if (purpose == CIRCUIT_PURPOSE_C_REND_JOINED && !must_be_open) { if (circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND && circ->purpose != CIRCUIT_PURPOSE_C_REND_READY && circ->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED && circ->purpose != CIRCUIT_PURPOSE_C_REND_JOINED) return 0; } else if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT && !must_be_open) { if (circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCING && circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) return 0; } else { if (purpose != circ->purpose) return 0; } /* If this is a timed-out hidden service circuit, skip it. */ if (origin_circ->hs_circ_has_timed_out) { return 0; } if (purpose == CIRCUIT_PURPOSE_C_GENERAL || purpose == CIRCUIT_PURPOSE_C_REND_JOINED) { if (circ->timestamp_dirty && circ->timestamp_dirty+get_options()->MaxCircuitDirtiness <= now) return 0; } if (origin_circ->unusable_for_new_conns) return 0; /* decide if this circ is suitable for this conn */ /* for rend circs, circ->cpath->prev is not the last router in the * circuit, it's the magical extra bob hop. so just check the nickname * of the one we meant to finish at. */ build_state = origin_circ->build_state; exitnode = build_state_get_exit_node(build_state); if (need_uptime && !build_state->need_uptime) return 0; if (need_internal != build_state->is_internal) return 0; if (purpose == CIRCUIT_PURPOSE_C_GENERAL) { tor_addr_t addr; const int family = tor_addr_parse(&addr, conn->socks_request->address); if (!exitnode && !build_state->onehop_tunnel) { log_debug(LD_CIRC,"Not considering circuit with unknown router."); return 0; /* this circuit is screwed and doesn't know it yet, * or is a rendezvous circuit. */ } if (build_state->onehop_tunnel) { if (!conn->want_onehop) { log_debug(LD_CIRC,"Skipping one-hop circuit."); return 0; } tor_assert(conn->chosen_exit_name); if (build_state->chosen_exit) { char digest[DIGEST_LEN]; if (hexdigest_to_digest(conn->chosen_exit_name, digest) < 0) return 0; /* broken digest, we don't want it */ if (tor_memneq(digest, build_state->chosen_exit->identity_digest, DIGEST_LEN)) return 0; /* this is a circuit to somewhere else */ if (tor_digest_is_zero(digest)) { /* we don't know the digest; have to compare addr:port */ if (family < 0 || !tor_addr_eq(&build_state->chosen_exit->addr, &addr) || build_state->chosen_exit->port != conn->socks_request->port) return 0; } } } else { if (conn->want_onehop) { /* don't use three-hop circuits -- that could hurt our anonymity. */ return 0; } } if (origin_circ->prepend_policy && family != -1) { int r = compare_tor_addr_to_addr_policy(&addr, conn->socks_request->port, origin_circ->prepend_policy); if (r == ADDR_POLICY_REJECTED) return 0; } if (exitnode && !connection_ap_can_use_exit(conn, exitnode)) { /* can't exit from this router */ return 0; } } else { /* not general */ const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(conn); if ((edge_conn->rend_data && !origin_circ->rend_data) || (!edge_conn->rend_data && origin_circ->rend_data) || (edge_conn->rend_data && origin_circ->rend_data && rend_cmp_service_ids(edge_conn->rend_data->onion_address, origin_circ->rend_data->onion_address))) { /* this circ is not for this conn */ return 0; } } if (!connection_edge_compatible_with_circuit(conn, origin_circ)) { /* conn needs to be isolated from other conns that have already used * origin_circ */ return 0; } return 1; } /** Return 1 if circuit a is better than circuit b for * conn, and return 0 otherwise. Used by circuit_get_best. */ static int circuit_is_better(const origin_circuit_t *oa, const origin_circuit_t *ob, const entry_connection_t *conn) { const circuit_t *a = TO_CIRCUIT(oa); const circuit_t *b = TO_CIRCUIT(ob); const uint8_t purpose = ENTRY_TO_CONN(conn)->purpose; int a_bits, b_bits; /* If one of the circuits was allowed to live due to relaxing its timeout, * it is definitely worse (it's probably a much slower path). */ if (oa->relaxed_timeout && !ob->relaxed_timeout) return 0; /* ob is better. It's not relaxed. */ if (!oa->relaxed_timeout && ob->relaxed_timeout) return 1; /* oa is better. It's not relaxed. */ switch (purpose) { case CIRCUIT_PURPOSE_C_GENERAL: /* if it's used but less dirty it's best; * else if it's more recently created it's best */ if (b->timestamp_dirty) { if (a->timestamp_dirty && a->timestamp_dirty > b->timestamp_dirty) return 1; } else { if (a->timestamp_dirty || timercmp(&a->timestamp_began, &b->timestamp_began, >)) return 1; if (ob->build_state->is_internal) /* XXX023 what the heck is this internal thing doing here. I * think we can get rid of it. circuit_is_acceptable() already * makes sure that is_internal is exactly what we need it to * be. -RD */ return 1; } break; case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT: /* the closer it is to ack_wait the better it is */ if (a->purpose > b->purpose) return 1; break; case CIRCUIT_PURPOSE_C_REND_JOINED: /* the closer it is to rend_joined the better it is */ if (a->purpose > b->purpose) return 1; break; } /* XXXX023 Maybe this check should get a higher priority to avoid * using up circuits too rapidly. */ a_bits = connection_edge_update_circuit_isolation(conn, (origin_circuit_t*)oa, 1); b_bits = connection_edge_update_circuit_isolation(conn, (origin_circuit_t*)ob, 1); /* if x_bits < 0, then we have not used x for anything; better not to dirty * a connection if we can help it. */ if (a_bits < 0) { return 0; } else if (b_bits < 0) { return 1; } a_bits &= ~ oa->isolation_flags_mixed; a_bits &= ~ ob->isolation_flags_mixed; if (n_bits_set_u8(a_bits) < n_bits_set_u8(b_bits)) { /* The fewer new restrictions we need to make on a circuit for stream * isolation, the better. */ return 1; } return 0; } /** Find the best circ that conn can use, preferably one which is * dirty. Circ must not be too old. * * Conn must be defined. * * If must_be_open, ignore circs not in CIRCUIT_STATE_OPEN. * * circ_purpose specifies what sort of circuit we must have. * It can be C_GENERAL, C_INTRODUCE_ACK_WAIT, or C_REND_JOINED. * * If it's REND_JOINED and must_be_open==0, then return the closest * rendezvous-purposed circuit that you can find. * * If it's INTRODUCE_ACK_WAIT and must_be_open==0, then return the * closest introduce-purposed circuit that you can find. */ static origin_circuit_t * circuit_get_best(const entry_connection_t *conn, int must_be_open, uint8_t purpose, int need_uptime, int need_internal) { circuit_t *circ; origin_circuit_t *best=NULL; struct timeval now; int intro_going_on_but_too_old = 0; tor_assert(conn); tor_assert(purpose == CIRCUIT_PURPOSE_C_GENERAL || purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT || purpose == CIRCUIT_PURPOSE_C_REND_JOINED); tor_gettimeofday(&now); TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { origin_circuit_t *origin_circ; if (!CIRCUIT_IS_ORIGIN(circ)) continue; origin_circ = TO_ORIGIN_CIRCUIT(circ); /* Log an info message if we're going to launch a new intro circ in * parallel */ if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT && !must_be_open && origin_circ->hs_circ_has_timed_out) { intro_going_on_but_too_old = 1; continue; } if (!circuit_is_acceptable(origin_circ,conn,must_be_open,purpose, need_uptime,need_internal,now.tv_sec)) continue; /* now this is an acceptable circ to hand back. but that doesn't * mean it's the *best* circ to hand back. try to decide. */ if (!best || circuit_is_better(origin_circ,best,conn)) best = origin_circ; } if (!best && intro_going_on_but_too_old) log_info(LD_REND|LD_CIRC, "There is an intro circuit being created " "right now, but it has already taken quite a while. Starting " "one in parallel."); return best; } /** Return the number of not-yet-open general-purpose origin circuits. */ static int count_pending_general_client_circuits(void) { const circuit_t *circ; int count = 0; TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { if (circ->marked_for_close || circ->state == CIRCUIT_STATE_OPEN || circ->purpose != CIRCUIT_PURPOSE_C_GENERAL || !CIRCUIT_IS_ORIGIN(circ)) continue; ++count; } return count; } #if 0 /** Check whether, according to the policies in options, the * circuit circ makes sense. */ /* XXXX currently only checks Exclude{Exit}Nodes; it should check more. * Also, it doesn't have the right definition of an exit circuit. Also, * it's never called. */ int circuit_conforms_to_options(const origin_circuit_t *circ, const or_options_t *options) { const crypt_path_t *cpath, *cpath_next = NULL; /* first check if it includes any excluded nodes */ for (cpath = circ->cpath; cpath_next != circ->cpath; cpath = cpath_next) { cpath_next = cpath->next; if (routerset_contains_extendinfo(options->ExcludeNodes, cpath->extend_info)) return 0; } /* then consider the final hop */ if (routerset_contains_extendinfo(options->ExcludeExitNodes, circ->cpath->prev->extend_info)) return 0; return 1; } #endif /** Close all circuits that start at us, aren't open, and were born * at least CircuitBuildTimeout seconds ago. */ void circuit_expire_building(void) { circuit_t *victim, *next_circ; /* circ_times.timeout_ms and circ_times.close_ms are from * circuit_build_times_get_initial_timeout() if we haven't computed * custom timeouts yet */ struct timeval general_cutoff, begindir_cutoff, fourhop_cutoff, close_cutoff, extremely_old_cutoff, hs_extremely_old_cutoff, cannibalized_cutoff, c_intro_cutoff, s_intro_cutoff, stream_cutoff; const or_options_t *options = get_options(); struct timeval now; cpath_build_state_t *build_state; int any_opened_circs = 0; tor_gettimeofday(&now); /* Check to see if we have any opened circuits. If we don't, * we want to be more lenient with timeouts, in case the * user has relocated and/or changed network connections. * See bug #3443. */ TOR_LIST_FOREACH(next_circ, circuit_get_global_list(), head) { if (!CIRCUIT_IS_ORIGIN(next_circ) || /* didn't originate here */ next_circ->marked_for_close) { /* don't mess with marked circs */ continue; } if (TO_ORIGIN_CIRCUIT(next_circ)->has_opened && next_circ->state == CIRCUIT_STATE_OPEN && TO_ORIGIN_CIRCUIT(next_circ)->build_state && TO_ORIGIN_CIRCUIT(next_circ)->build_state->desired_path_len == DEFAULT_ROUTE_LEN) { any_opened_circs = 1; break; } } #define SET_CUTOFF(target, msec) do { \ long ms = tor_lround(msec); \ struct timeval diff; \ diff.tv_sec = ms / 1000; \ diff.tv_usec = (int)((ms % 1000) * 1000); \ timersub(&now, &diff, &target); \ } while (0) /** * Because circuit build timeout is calculated only based on 3 hop * general purpose circuit construction, we need to scale the timeout * to make it properly apply to longer circuits, and circuits of * certain usage types. The following diagram illustrates how we * derive the scaling below. In short, we calculate the number * of times our telescoping-based circuit construction causes cells * to traverse each link for the circuit purpose types in question, * and then assume each link is equivalent. * * OP --a--> A --b--> B --c--> C * OP --a--> A --b--> B --c--> C --d--> D * * Let h = a = b = c = d * * Three hops (general_cutoff) * RTTs = 3a + 2b + c * RTTs = 6h * Cannibalized: * RTTs = a+b+c+d * RTTs = 4h * Four hops: * RTTs = 4a + 3b + 2c + d * RTTs = 10h * Client INTRODUCE1+ACK: // XXX: correct? * RTTs = 5a + 4b + 3c + 2d * RTTs = 14h * Server intro: * RTTs = 4a + 3b + 2c * RTTs = 9h */ SET_CUTOFF(general_cutoff, get_circuit_build_timeout_ms()); SET_CUTOFF(begindir_cutoff, get_circuit_build_timeout_ms()); /* > 3hop circs seem to have a 1.0 second delay on their cannibalized * 4th hop. */ SET_CUTOFF(fourhop_cutoff, get_circuit_build_timeout_ms() * (10/6.0) + 1000); /* CIRCUIT_PURPOSE_C_ESTABLISH_REND behaves more like a RELAY cell. * Use the stream cutoff (more or less). */ SET_CUTOFF(stream_cutoff, MAX(options->CircuitStreamTimeout,15)*1000 + 1000); /* Be lenient with cannibalized circs. They already survived the official * CBT, and they're usually not performance-critical. */ SET_CUTOFF(cannibalized_cutoff, MAX(get_circuit_build_close_time_ms()*(4/6.0), options->CircuitStreamTimeout * 1000) + 1000); /* Intro circs have an extra round trip (and are also 4 hops long) */ SET_CUTOFF(c_intro_cutoff, get_circuit_build_timeout_ms() * (14/6.0) + 1000); /* Server intro circs have an extra round trip */ SET_CUTOFF(s_intro_cutoff, get_circuit_build_timeout_ms() * (9/6.0) + 1000); SET_CUTOFF(close_cutoff, get_circuit_build_close_time_ms()); SET_CUTOFF(extremely_old_cutoff, get_circuit_build_close_time_ms()*2 + 1000); SET_CUTOFF(hs_extremely_old_cutoff, MAX(get_circuit_build_close_time_ms()*2 + 1000, options->SocksTimeout * 1000)); TOR_LIST_FOREACH(next_circ, circuit_get_global_list(), head) { struct timeval cutoff; victim = next_circ; if (!CIRCUIT_IS_ORIGIN(victim) || /* didn't originate here */ victim->marked_for_close) /* don't mess with marked circs */ continue; /* If we haven't yet started the first hop, it means we don't have * any orconns available, and thus have not started counting time yet * for this circuit. See circuit_deliver_create_cell() and uses of * timestamp_began. * * Continue to wait in this case. The ORConn should timeout * independently and kill us then. */ if (TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_CLOSED) { continue; } build_state = TO_ORIGIN_CIRCUIT(victim)->build_state; if (build_state && build_state->onehop_tunnel) cutoff = begindir_cutoff; else if (victim->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) cutoff = close_cutoff; else if (victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING || victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) cutoff = c_intro_cutoff; else if (victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO) cutoff = s_intro_cutoff; else if (victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND) cutoff = stream_cutoff; else if (victim->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING) cutoff = close_cutoff; else if (TO_ORIGIN_CIRCUIT(victim)->has_opened && victim->state != CIRCUIT_STATE_OPEN) cutoff = cannibalized_cutoff; else if (build_state && build_state->desired_path_len >= 4) cutoff = fourhop_cutoff; else cutoff = general_cutoff; if (TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out) cutoff = hs_extremely_old_cutoff; if (timercmp(&victim->timestamp_began, &cutoff, >)) continue; /* it's still young, leave it alone */ /* We need to double-check the opened state here because * we don't want to consider opened 1-hop dircon circuits for * deciding when to relax the timeout, but we *do* want to relax * those circuits too if nothing else is opened *and* they still * aren't either. */ if (!any_opened_circs && victim->state != CIRCUIT_STATE_OPEN) { /* It's still young enough that we wouldn't close it, right? */ if (timercmp(&victim->timestamp_began, &close_cutoff, >)) { if (!TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout) { int first_hop_succeeded = TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_OPEN; log_info(LD_CIRC, "No circuits are opened. Relaxing timeout for circuit %d " "(a %s %d-hop circuit in state %s with channel state %s). " "%d guards are live.", TO_ORIGIN_CIRCUIT(victim)->global_identifier, circuit_purpose_to_string(victim->purpose), TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len, circuit_state_to_string(victim->state), channel_state_to_string(victim->n_chan->state), num_live_entry_guards(0)); /* We count the timeout here for CBT, because technically this * was a timeout, and the timeout value needs to reset if we * see enough of them. Note this means we also need to avoid * double-counting below, too. */ circuit_build_times_count_timeout(get_circuit_build_times_mutable(), first_hop_succeeded); TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout = 1; } continue; } else { static ratelim_t relax_timeout_limit = RATELIM_INIT(3600); const double build_close_ms = get_circuit_build_close_time_ms(); log_fn_ratelim(&relax_timeout_limit, LOG_NOTICE, LD_CIRC, "No circuits are opened. Relaxed timeout for circuit %d " "(a %s %d-hop circuit in state %s with channel state %s) to " "%ldms. However, it appears the circuit has timed out " "anyway. %d guards are live.", TO_ORIGIN_CIRCUIT(victim)->global_identifier, circuit_purpose_to_string(victim->purpose), TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len, circuit_state_to_string(victim->state), channel_state_to_string(victim->n_chan->state), (long)build_close_ms, num_live_entry_guards(0)); } } #if 0 /* some debug logs, to help track bugs */ if (victim->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING && victim->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) { if (!victim->timestamp_dirty) log_fn(LOG_DEBUG,"Considering %sopen purpose %d to %s (circid %d)." "(clean).", victim->state == CIRCUIT_STATE_OPEN ? "" : "non", victim->purpose, victim->build_state->chosen_exit_name, victim->n_circ_id); else log_fn(LOG_DEBUG,"Considering %sopen purpose %d to %s (circid %d). " "%d secs since dirty.", victim->state == CIRCUIT_STATE_OPEN ? "" : "non", victim->purpose, victim->build_state->chosen_exit_name, victim->n_circ_id, (int)(now - victim->timestamp_dirty)); } #endif /* if circ is !open, or if it's open but purpose is a non-finished * intro or rend, then mark it for close */ if (victim->state == CIRCUIT_STATE_OPEN) { switch (victim->purpose) { default: /* most open circuits can be left alone. */ continue; /* yes, continue inside a switch refers to the nearest * enclosing loop. C is smart. */ case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: break; /* too old, need to die */ case CIRCUIT_PURPOSE_C_REND_READY: /* it's a rend_ready circ -- has it already picked a query? */ /* c_rend_ready circs measure age since timestamp_dirty, * because that's set when they switch purposes */ if (TO_ORIGIN_CIRCUIT(victim)->rend_data || victim->timestamp_dirty > cutoff.tv_sec) continue; break; case CIRCUIT_PURPOSE_PATH_BIAS_TESTING: /* Open path bias testing circuits are given a long * time to complete the test, but not forever */ TO_ORIGIN_CIRCUIT(victim)->path_state = PATH_STATE_USE_FAILED; break; case CIRCUIT_PURPOSE_C_INTRODUCING: /* We keep old introducing circuits around for * a while in parallel, and they can end up "opened". * We decide below if we're going to mark them timed * out and eventually close them. */ break; case CIRCUIT_PURPOSE_C_ESTABLISH_REND: case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED: case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT: /* rend and intro circs become dirty each time they * make an introduction attempt. so timestamp_dirty * will reflect the time since the last attempt. */ if (victim->timestamp_dirty > cutoff.tv_sec) continue; break; } } else { /* circuit not open, consider recording failure as timeout */ int first_hop_succeeded = TO_ORIGIN_CIRCUIT(victim)->cpath && TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_OPEN; if (TO_ORIGIN_CIRCUIT(victim)->p_streams != NULL) { log_warn(LD_BUG, "Circuit %d (purpose %d, %s) has timed out, " "yet has attached streams!", TO_ORIGIN_CIRCUIT(victim)->global_identifier, victim->purpose, circuit_purpose_to_string(victim->purpose)); tor_fragile_assert(); continue; } if (circuit_timeout_want_to_count_circ(TO_ORIGIN_CIRCUIT(victim)) && circuit_build_times_enough_to_compute(get_circuit_build_times())) { /* Circuits are allowed to last longer for measurement. * Switch their purpose and wait. */ if (victim->purpose != CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) { control_event_circuit_status(TO_ORIGIN_CIRCUIT(victim), CIRC_EVENT_FAILED, END_CIRC_REASON_TIMEOUT); circuit_change_purpose(victim, CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT); /* Record this failure to check for too many timeouts * in a row. This function does not record a time value yet * (we do that later); it only counts the fact that we did * have a timeout. We also want to avoid double-counting * already "relaxed" circuits, which are counted above. */ if (!TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout) { circuit_build_times_count_timeout( get_circuit_build_times_mutable(), first_hop_succeeded); } continue; } /* * If the circuit build time is much greater than we would have cut * it off at, we probably had a suspend event along this codepath, * and we should discard the value. */ if (timercmp(&victim->timestamp_began, &extremely_old_cutoff, <)) { log_notice(LD_CIRC, "Extremely large value for circuit build timeout: %lds. " "Assuming clock jump. Purpose %d (%s)", (long)(now.tv_sec - victim->timestamp_began.tv_sec), victim->purpose, circuit_purpose_to_string(victim->purpose)); } else if (circuit_build_times_count_close( get_circuit_build_times_mutable(), first_hop_succeeded, victim->timestamp_created.tv_sec)) { circuit_build_times_set_timeout(get_circuit_build_times_mutable()); } } } /* If this is a hidden service client circuit which is far enough * along in connecting to its destination, and we haven't already * flagged it as 'timed out', and the user has not told us to * close such circs immediately on timeout, flag it as 'timed out' * so we'll launch another intro or rend circ, but don't mark it * for close yet. * * (Circs flagged as 'timed out' are given a much longer timeout * period above, so we won't close them in the next call to * circuit_expire_building.) */ if (!(options->CloseHSClientCircuitsImmediatelyOnTimeout) && !(TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out)) { switch (victim->purpose) { case CIRCUIT_PURPOSE_C_REND_READY: /* We only want to spare a rend circ if it has been specified in * an INTRODUCE1 cell sent to a hidden service. A circ's * pending_final_cpath field is non-NULL iff it is a rend circ * and we have tried to send an INTRODUCE1 cell specifying it. * Thus, if the pending_final_cpath field *is* NULL, then we * want to not spare it. */ if (TO_ORIGIN_CIRCUIT(victim)->build_state->pending_final_cpath == NULL) break; /* fallthrough! */ case CIRCUIT_PURPOSE_C_INTRODUCING: /* connection_ap_handshake_attach_circuit() will relaunch for us */ case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT: case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED: /* If we have reached this line, we want to spare the circ for now. */ log_info(LD_CIRC,"Marking circ %u (state %d:%s, purpose %d) " "as timed-out HS circ", (unsigned)victim->n_circ_id, victim->state, circuit_state_to_string(victim->state), victim->purpose); TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out = 1; continue; default: break; } } /* If this is a service-side rendezvous circuit which is far * enough along in connecting to its destination, consider sparing * it. */ if (!(options->CloseHSServiceRendCircuitsImmediatelyOnTimeout) && !(TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out) && victim->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) { log_info(LD_CIRC,"Marking circ %u (state %d:%s, purpose %d) " "as timed-out HS circ; relaunching rendezvous attempt.", (unsigned)victim->n_circ_id, victim->state, circuit_state_to_string(victim->state), victim->purpose); TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out = 1; rend_service_relaunch_rendezvous(TO_ORIGIN_CIRCUIT(victim)); continue; } if (victim->n_chan) log_info(LD_CIRC, "Abandoning circ %u %s:%u (state %d,%d:%s, purpose %d, " "len %d)", TO_ORIGIN_CIRCUIT(victim)->global_identifier, channel_get_canonical_remote_descr(victim->n_chan), (unsigned)victim->n_circ_id, TO_ORIGIN_CIRCUIT(victim)->has_opened, victim->state, circuit_state_to_string(victim->state), victim->purpose, TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len); else log_info(LD_CIRC, "Abandoning circ %u %u (state %d,%d:%s, purpose %d, len %d)", TO_ORIGIN_CIRCUIT(victim)->global_identifier, (unsigned)victim->n_circ_id, TO_ORIGIN_CIRCUIT(victim)->has_opened, victim->state, circuit_state_to_string(victim->state), victim->purpose, TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len); circuit_log_path(LOG_INFO,LD_CIRC,TO_ORIGIN_CIRCUIT(victim)); if (victim->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) circuit_mark_for_close(victim, END_CIRC_REASON_MEASUREMENT_EXPIRED); else circuit_mark_for_close(victim, END_CIRC_REASON_TIMEOUT); pathbias_count_timeout(TO_ORIGIN_CIRCUIT(victim)); } } /** Remove any elements in needed_ports that are handled by an * open or in-progress circuit. */ void circuit_remove_handled_ports(smartlist_t *needed_ports) { int i; uint16_t *port; for (i = 0; i < smartlist_len(needed_ports); ++i) { port = smartlist_get(needed_ports, i); tor_assert(*port); if (circuit_stream_is_being_handled(NULL, *port, MIN_CIRCUITS_HANDLING_STREAM)) { // log_debug(LD_CIRC,"Port %d is already being handled; removing.", port); smartlist_del(needed_ports, i--); tor_free(port); } else { log_debug(LD_CIRC,"Port %d is not handled.", *port); } } } /** Return 1 if at least min general-purpose non-internal circuits * will have an acceptable exit node for exit stream conn if it * is defined, else for "*:port". * Else return 0. */ int circuit_stream_is_being_handled(entry_connection_t *conn, uint16_t port, int min) { circuit_t *circ; const node_t *exitnode; int num=0; time_t now = time(NULL); int need_uptime = smartlist_contains_int_as_string( get_options()->LongLivedPorts, conn ? conn->socks_request->port : port); TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { if (CIRCUIT_IS_ORIGIN(circ) && !circ->marked_for_close && circ->purpose == CIRCUIT_PURPOSE_C_GENERAL && (!circ->timestamp_dirty || circ->timestamp_dirty + get_options()->MaxCircuitDirtiness > now)) { origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ); cpath_build_state_t *build_state = origin_circ->build_state; if (build_state->is_internal || build_state->onehop_tunnel) continue; if (origin_circ->unusable_for_new_conns) continue; exitnode = build_state_get_exit_node(build_state); if (exitnode && (!need_uptime || build_state->need_uptime)) { int ok; if (conn) { ok = connection_ap_can_use_exit(conn, exitnode); } else { addr_policy_result_t r; r = compare_tor_addr_to_node_policy(NULL, port, exitnode); ok = r != ADDR_POLICY_REJECTED && r != ADDR_POLICY_PROBABLY_REJECTED; } if (ok) { if (++num >= min) return 1; } } } } return 0; } /** Don't keep more than this many unused open circuits around. */ #define MAX_UNUSED_OPEN_CIRCUITS 14 /** Figure out how many circuits we have open that are clean. Make * sure it's enough for all the upcoming behaviors we predict we'll have. * But put an upper bound on the total number of circuits. */ static void circuit_predict_and_launch_new(void) { circuit_t *circ; int num=0, num_internal=0, num_uptime_internal=0; int hidserv_needs_uptime=0, hidserv_needs_capacity=1; int port_needs_uptime=0, port_needs_capacity=1; time_t now = time(NULL); int flags = 0; /* First, count how many of each type of circuit we have already. */ TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { cpath_build_state_t *build_state; origin_circuit_t *origin_circ; if (!CIRCUIT_IS_ORIGIN(circ)) continue; if (circ->marked_for_close) continue; /* don't mess with marked circs */ if (circ->timestamp_dirty) continue; /* only count clean circs */ if (circ->purpose != CIRCUIT_PURPOSE_C_GENERAL) continue; /* only pay attention to general-purpose circs */ origin_circ = TO_ORIGIN_CIRCUIT(circ); if (origin_circ->unusable_for_new_conns) continue; build_state = origin_circ->build_state; if (build_state->onehop_tunnel) continue; num++; if (build_state->is_internal) num_internal++; if (build_state->need_uptime && build_state->is_internal) num_uptime_internal++; } /* If that's enough, then stop now. */ if (num >= MAX_UNUSED_OPEN_CIRCUITS) return; /* we already have many, making more probably will hurt */ /* Second, see if we need any more exit circuits. */ /* check if we know of a port that's been requested recently * and no circuit is currently available that can handle it. */ if (!circuit_all_predicted_ports_handled(now, &port_needs_uptime, &port_needs_capacity)) { if (port_needs_uptime) flags |= CIRCLAUNCH_NEED_UPTIME; if (port_needs_capacity) flags |= CIRCLAUNCH_NEED_CAPACITY; log_info(LD_CIRC, "Have %d clean circs (%d internal), need another exit circ.", num, num_internal); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags); return; } /* Third, see if we need any more hidden service (server) circuits. */ if (num_rend_services() && num_uptime_internal < 3) { flags = (CIRCLAUNCH_NEED_CAPACITY | CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL); log_info(LD_CIRC, "Have %d clean circs (%d internal), need another internal " "circ for my hidden service.", num, num_internal); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags); return; } /* Fourth, see if we need any more hidden service (client) circuits. */ if (rep_hist_get_predicted_internal(now, &hidserv_needs_uptime, &hidserv_needs_capacity) && ((num_uptime_internal<2 && hidserv_needs_uptime) || num_internal<2)) { if (hidserv_needs_uptime) flags |= CIRCLAUNCH_NEED_UPTIME; if (hidserv_needs_capacity) flags |= CIRCLAUNCH_NEED_CAPACITY; flags |= CIRCLAUNCH_IS_INTERNAL; log_info(LD_CIRC, "Have %d clean circs (%d uptime-internal, %d internal), need" " another hidden service circ.", num, num_uptime_internal, num_internal); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags); return; } /* Finally, check to see if we still need more circuits to learn * a good build timeout. But if we're close to our max number we * want, don't do another -- we want to leave a few slots open so * we can still build circuits preemptively as needed. */ if (num < MAX_UNUSED_OPEN_CIRCUITS-2 && ! circuit_build_times_disabled() && circuit_build_times_needs_circuits_now(get_circuit_build_times())) { flags = CIRCLAUNCH_NEED_CAPACITY; log_info(LD_CIRC, "Have %d clean circs need another buildtime test circ.", num); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags); return; } } /** Build a new test circuit every 5 minutes */ #define TESTING_CIRCUIT_INTERVAL 300 /** This function is called once a second, if router_have_min_dir_info() is * true. Its job is to make sure all services we offer have enough circuits * available. Some services just want enough circuits for current tasks, * whereas others want a minimum set of idle circuits hanging around. */ void circuit_build_needed_circs(time_t now) { static time_t time_to_new_circuit = 0; const or_options_t *options = get_options(); /* launch a new circ for any pending streams that need one */ connection_ap_attach_pending(); /* make sure any hidden services have enough intro points */ rend_services_introduce(); if (time_to_new_circuit < now) { circuit_reset_failure_count(1); time_to_new_circuit = now + options->NewCircuitPeriod; if (proxy_mode(get_options())) addressmap_clean(now); circuit_expire_old_circuits_clientside(); #if 0 /* disable for now, until predict-and-launch-new can cull leftovers */ circ = circuit_get_youngest_clean_open(CIRCUIT_PURPOSE_C_GENERAL); if (get_options()->RunTesting && circ && circ->timestamp_began.tv_sec + TESTING_CIRCUIT_INTERVAL < now) { log_fn(LOG_INFO,"Creating a new testing circuit."); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, 0); } #endif } if (!options->DisablePredictedCircuits) circuit_predict_and_launch_new(); } /** If the stream conn is a member of any of the linked * lists of circ, then remove it from the list. */ void circuit_detach_stream(circuit_t *circ, edge_connection_t *conn) { edge_connection_t *prevconn; tor_assert(circ); tor_assert(conn); if (conn->base_.type == CONN_TYPE_AP) { entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn); entry_conn->may_use_optimistic_data = 0; } conn->cpath_layer = NULL; /* don't keep a stale pointer */ conn->on_circuit = NULL; if (CIRCUIT_IS_ORIGIN(circ)) { origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ); if (conn == origin_circ->p_streams) { origin_circ->p_streams = conn->next_stream; return; } for (prevconn = origin_circ->p_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ; if (prevconn && prevconn->next_stream) { prevconn->next_stream = conn->next_stream; return; } } else { or_circuit_t *or_circ = TO_OR_CIRCUIT(circ); if (conn == or_circ->n_streams) { or_circ->n_streams = conn->next_stream; return; } if (conn == or_circ->resolving_streams) { or_circ->resolving_streams = conn->next_stream; return; } for (prevconn = or_circ->n_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ; if (prevconn && prevconn->next_stream) { prevconn->next_stream = conn->next_stream; return; } for (prevconn = or_circ->resolving_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ; if (prevconn && prevconn->next_stream) { prevconn->next_stream = conn->next_stream; return; } } log_warn(LD_BUG,"Edge connection not in circuit's list."); /* Don't give an error here; it's harmless. */ tor_fragile_assert(); } /** If we haven't yet decided on a good timeout value for circuit * building, we close idles circuits aggressively so we can get more * data points. */ #define IDLE_TIMEOUT_WHILE_LEARNING (10*60) /** Find each circuit that has been unused for too long, or dirty * for too long and has no streams on it: mark it for close. */ static void circuit_expire_old_circuits_clientside(void) { circuit_t *circ; struct timeval cutoff, now; tor_gettimeofday(&now); cutoff = now; if (! circuit_build_times_disabled() && circuit_build_times_needs_circuits(get_circuit_build_times())) { /* Circuits should be shorter lived if we need more of them * for learning a good build timeout */ cutoff.tv_sec -= IDLE_TIMEOUT_WHILE_LEARNING; } else { cutoff.tv_sec -= get_options()->CircuitIdleTimeout; } TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { if (circ->marked_for_close || !CIRCUIT_IS_ORIGIN(circ)) continue; /* If the circuit has been dirty for too long, and there are no streams * on it, mark it for close. */ if (circ->timestamp_dirty && circ->timestamp_dirty + get_options()->MaxCircuitDirtiness < now.tv_sec && !TO_ORIGIN_CIRCUIT(circ)->p_streams /* nothing attached */ ) { log_debug(LD_CIRC, "Closing n_circ_id %u (dirty %ld sec ago, " "purpose %d)", (unsigned)circ->n_circ_id, (long)(now.tv_sec - circ->timestamp_dirty), circ->purpose); /* Don't do this magic for testing circuits. Their death is governed * by circuit_expire_building */ if (circ->purpose != CIRCUIT_PURPOSE_PATH_BIAS_TESTING) circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED); } else if (!circ->timestamp_dirty && circ->state == CIRCUIT_STATE_OPEN) { if (timercmp(&circ->timestamp_began, &cutoff, <)) { if (circ->purpose == CIRCUIT_PURPOSE_C_GENERAL || circ->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT || circ->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO || circ->purpose == CIRCUIT_PURPOSE_TESTING || (circ->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING && circ->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) || circ->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) { log_debug(LD_CIRC, "Closing circuit that has been unused for %ld msec.", tv_mdiff(&circ->timestamp_began, &now)); circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED); } else if (!TO_ORIGIN_CIRCUIT(circ)->is_ancient) { /* Server-side rend joined circuits can end up really old, because * they are reused by clients for longer than normal. The client * controls their lifespan. (They never become dirty, because * connection_exit_begin_conn() never marks anything as dirty.) * Similarly, server-side intro circuits last a long time. */ if (circ->purpose != CIRCUIT_PURPOSE_S_REND_JOINED && circ->purpose != CIRCUIT_PURPOSE_S_INTRO) { log_notice(LD_CIRC, "Ancient non-dirty circuit %d is still around after " "%ld milliseconds. Purpose: %d (%s)", TO_ORIGIN_CIRCUIT(circ)->global_identifier, tv_mdiff(&circ->timestamp_began, &now), circ->purpose, circuit_purpose_to_string(circ->purpose)); TO_ORIGIN_CIRCUIT(circ)->is_ancient = 1; } } } } } } /** How long do we wait before killing circuits with the properties * described below? * * Probably we could choose a number here as low as 5 to 10 seconds, * since these circs are used for begindir, and a) generally you either * ask another begindir question right after or you don't for a long time, * b) clients at least through 0.2.1.x choose from the whole set of * directory mirrors at each choice, and c) re-establishing a one-hop * circuit via create-fast is a light operation assuming the TLS conn is * still there. * * I expect "b" to go away one day when we move to using directory * guards, but I think "a" and "c" are good enough reasons that a low * number is safe even then. */ #define IDLE_ONE_HOP_CIRC_TIMEOUT 60 /** Find each non-origin circuit that has been unused for too long, * has no streams on it, used a create_fast, and ends here: mark it * for close. */ void circuit_expire_old_circuits_serverside(time_t now) { circuit_t *circ; or_circuit_t *or_circ; time_t cutoff = now - IDLE_ONE_HOP_CIRC_TIMEOUT; TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { if (circ->marked_for_close || CIRCUIT_IS_ORIGIN(circ)) continue; or_circ = TO_OR_CIRCUIT(circ); /* If the circuit has been idle for too long, and there are no streams * on it, and it ends here, and it used a create_fast, mark it for close. */ if (or_circ->is_first_hop && !circ->n_chan && !or_circ->n_streams && !or_circ->resolving_streams && or_circ->p_chan && channel_when_last_xmit(or_circ->p_chan) <= cutoff) { log_info(LD_CIRC, "Closing circ_id %u (empty %d secs ago)", (unsigned)or_circ->p_circ_id, (int)(now - channel_when_last_xmit(or_circ->p_chan))); circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED); } } } /** Number of testing circuits we want open before testing our bandwidth. */ #define NUM_PARALLEL_TESTING_CIRCS 4 /** True iff we've ever had enough testing circuits open to test our * bandwidth. */ static int have_performed_bandwidth_test = 0; /** Reset have_performed_bandwidth_test, so we'll start building * testing circuits again so we can exercise our bandwidth. */ void reset_bandwidth_test(void) { have_performed_bandwidth_test = 0; } /** Return 1 if we've already exercised our bandwidth, or if we * have fewer than NUM_PARALLEL_TESTING_CIRCS testing circuits * established or on the way. Else return 0. */ int circuit_enough_testing_circs(void) { circuit_t *circ; int num = 0; if (have_performed_bandwidth_test) return 1; TOR_LIST_FOREACH(circ, circuit_get_global_list(), head) { if (!circ->marked_for_close && CIRCUIT_IS_ORIGIN(circ) && circ->purpose == CIRCUIT_PURPOSE_TESTING && circ->state == CIRCUIT_STATE_OPEN) num++; } return num >= NUM_PARALLEL_TESTING_CIRCS; } /** A testing circuit has completed. Take whatever stats we want. * Noticing reachability is taken care of in onionskin_answer(), * so there's no need to record anything here. But if we still want * to do the bandwidth test, and we now have enough testing circuits * open, do it. */ static void circuit_testing_opened(origin_circuit_t *circ) { if (have_performed_bandwidth_test || !check_whether_orport_reachable()) { /* either we've already done everything we want with testing circuits, * or this testing circuit became open due to a fluke, e.g. we picked * a last hop where we already had the connection open due to an * outgoing local circuit. */ circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_AT_ORIGIN); } else if (circuit_enough_testing_circs()) { router_perform_bandwidth_test(NUM_PARALLEL_TESTING_CIRCS, time(NULL)); have_performed_bandwidth_test = 1; } else consider_testing_reachability(1, 0); } /** A testing circuit has failed to build. Take whatever stats we want. */ static void circuit_testing_failed(origin_circuit_t *circ, int at_last_hop) { if (server_mode(get_options()) && check_whether_orport_reachable()) return; log_info(LD_GENERAL, "Our testing circuit (to see if your ORPort is reachable) " "has failed. I'll try again later."); /* These aren't used yet. */ (void)circ; (void)at_last_hop; } /** The circuit circ has just become open. Take the next * step: for rendezvous circuits, we pass circ to the appropriate * function in rendclient or rendservice. For general circuits, we * call connection_ap_attach_pending, which looks for pending streams * that could use circ. */ void circuit_has_opened(origin_circuit_t *circ) { control_event_circuit_status(circ, CIRC_EVENT_BUILT, 0); /* Remember that this circuit has finished building. Now if we start * it building again later (e.g. by extending it), we will know not * to consider its build time. */ circ->has_opened = 1; switch (TO_CIRCUIT(circ)->purpose) { case CIRCUIT_PURPOSE_C_ESTABLISH_REND: rend_client_rendcirc_has_opened(circ); /* Start building an intro circ if we don't have one yet. */ connection_ap_attach_pending(); /* This isn't a call to circuit_try_attaching_streams because a * circuit in _C_ESTABLISH_REND state isn't connected to its * hidden service yet, thus we can't attach streams to it yet, * thus circuit_try_attaching_streams would always clear the * circuit's isolation state. circuit_try_attaching_streams is * called later, when the rend circ enters _C_REND_JOINED * state. */ break; case CIRCUIT_PURPOSE_C_INTRODUCING: rend_client_introcirc_has_opened(circ); break; case CIRCUIT_PURPOSE_C_GENERAL: /* Tell any AP connections that have been waiting for a new * circuit that one is ready. */ circuit_try_attaching_streams(circ); break; case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* at Bob, waiting for introductions */ rend_service_intro_has_opened(circ); break; case CIRCUIT_PURPOSE_S_CONNECT_REND: /* at Bob, connecting to rend point */ rend_service_rendezvous_has_opened(circ); break; case CIRCUIT_PURPOSE_TESTING: circuit_testing_opened(circ); break; /* default: * This won't happen in normal operation, but might happen if the * controller did it. Just let it slide. */ } } /** If the stream-isolation state of circ can be cleared, clear * it. Return non-zero iff circ's isolation state was cleared. */ static int circuit_try_clearing_isolation_state(origin_circuit_t *circ) { if (/* The circuit may have become non-open if it was cannibalized.*/ circ->base_.state == CIRCUIT_STATE_OPEN && /* If !isolation_values_set, there is nothing to clear. */ circ->isolation_values_set && /* It's not legal to clear a circuit's isolation info if it's ever had * streams attached */ !circ->isolation_any_streams_attached) { /* If we have any isolation information set on this circuit, and * we didn't manage to attach any streams to it, then we can * and should clear it and try again. */ circuit_clear_isolation(circ); return 1; } else { return 0; } } /** Called when a circuit becomes ready for streams to be attached to * it. */ void circuit_try_attaching_streams(origin_circuit_t *circ) { /* Attach streams to this circuit if we can. */ connection_ap_attach_pending(); /* The call to circuit_try_clearing_isolation_state here will do * nothing and return 0 if we didn't attach any streams to circ * above. */ if (circuit_try_clearing_isolation_state(circ)) { /* Maybe *now* we can attach some streams to this circuit. */ connection_ap_attach_pending(); } } /** Called whenever a circuit could not be successfully built. */ void circuit_build_failed(origin_circuit_t *circ) { channel_t *n_chan = NULL; /* we should examine circ and see if it failed because of * the last hop or an earlier hop. then use this info below. */ int failed_at_last_hop = 0; /* If the last hop isn't open, and the second-to-last is, we failed * at the last hop. */ if (circ->cpath && circ->cpath->prev->state != CPATH_STATE_OPEN && circ->cpath->prev->prev->state == CPATH_STATE_OPEN) { failed_at_last_hop = 1; } if (circ->cpath && circ->cpath->state != CPATH_STATE_OPEN && ! circ->base_.received_destroy) { /* We failed at the first hop for some reason other than a DESTROY cell. * If there's an OR connection to blame, blame it. Also, avoid this relay * for a while, and fail any one-hop directory fetches destined for it. */ const char *n_chan_id = circ->cpath->extend_info->identity_digest; int already_marked = 0; if (circ->base_.n_chan) { n_chan = circ->base_.n_chan; if (n_chan->is_bad_for_new_circs) { /* We only want to blame this router when a fresh healthy * connection fails. So don't mark this router as newly failed, * since maybe this was just an old circuit attempt that's * finally timing out now. Also, there's no need to blow away * circuits/streams/etc, since the failure of an unhealthy conn * doesn't tell us much about whether a healthy conn would * succeed. */ already_marked = 1; } log_info(LD_OR, "Our circuit failed to get a response from the first hop " "(%s). I'm going to try to rotate to a better connection.", channel_get_canonical_remote_descr(n_chan)); n_chan->is_bad_for_new_circs = 1; } else { log_info(LD_OR, "Our circuit died before the first hop with no connection"); } if (n_chan_id && !already_marked) { entry_guard_register_connect_status(n_chan_id, 0, 1, time(NULL)); /* if there are any one-hop streams waiting on this circuit, fail * them now so they can retry elsewhere. */ connection_ap_fail_onehop(n_chan_id, circ->build_state); } } switch (circ->base_.purpose) { case CIRCUIT_PURPOSE_C_GENERAL: /* If we never built the circuit, note it as a failure. */ circuit_increment_failure_count(); if (failed_at_last_hop) { /* Make sure any streams that demand our last hop as their exit * know that it's unlikely to happen. */ circuit_discard_optional_exit_enclaves(circ->cpath->prev->extend_info); } break; case CIRCUIT_PURPOSE_TESTING: circuit_testing_failed(circ, failed_at_last_hop); break; case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* at Bob, waiting for introductions */ if (circ->base_.state != CIRCUIT_STATE_OPEN) { circuit_increment_failure_count(); } /* no need to care here, because bob will rebuild intro * points periodically. */ break; case CIRCUIT_PURPOSE_C_INTRODUCING: /* at Alice, connecting to intro point */ /* Don't increment failure count, since Bob may have picked * the introduction point maliciously */ /* Alice will pick a new intro point when this one dies, if * the stream in question still cares. No need to act here. */ break; case CIRCUIT_PURPOSE_C_ESTABLISH_REND: /* at Alice, waiting for Bob */ circuit_increment_failure_count(); /* Alice will pick a new rend point when this one dies, if * the stream in question still cares. No need to act here. */ break; case CIRCUIT_PURPOSE_S_CONNECT_REND: /* at Bob, connecting to rend point */ /* Don't increment failure count, since Alice may have picked * the rendezvous point maliciously */ log_info(LD_REND, "Couldn't connect to Alice's chosen rend point %s " "(%s hop failed).", escaped(build_state_get_exit_nickname(circ->build_state)), failed_at_last_hop?"last":"non-last"); rend_service_relaunch_rendezvous(circ); break; /* default: * This won't happen in normal operation, but might happen if the * controller did it. Just let it slide. */ } } /** Number of consecutive failures so far; should only be touched by * circuit_launch_new and circuit_*_failure_count. */ static int n_circuit_failures = 0; /** Before the last time we called circuit_reset_failure_count(), were * there a lot of failures? */ static int did_circs_fail_last_period = 0; /** Don't retry launching a new circuit if we try this many times with no * success. */ #define MAX_CIRCUIT_FAILURES 5 /** Launch a new circuit; see circuit_launch_by_extend_info() for * details on arguments. */ origin_circuit_t * circuit_launch(uint8_t purpose, int flags) { return circuit_launch_by_extend_info(purpose, NULL, flags); } /** Launch a new circuit with purpose purpose and exit node * extend_info (or NULL to select a random exit node). If flags * contains CIRCLAUNCH_NEED_UPTIME, choose among routers with high uptime. If * CIRCLAUNCH_NEED_CAPACITY is set, choose among routers with high bandwidth. * If CIRCLAUNCH_IS_INTERNAL is true, the last hop need not be an exit node. * If CIRCLAUNCH_ONEHOP_TUNNEL is set, the circuit will have only one hop. * Return the newly allocated circuit on success, or NULL on failure. */ origin_circuit_t * circuit_launch_by_extend_info(uint8_t purpose, extend_info_t *extend_info, int flags) { origin_circuit_t *circ; int onehop_tunnel = (flags & CIRCLAUNCH_ONEHOP_TUNNEL) != 0; if (!onehop_tunnel && !router_have_minimum_dir_info()) { log_debug(LD_CIRC,"Haven't fetched enough directory info yet; canceling " "circuit launch."); return NULL; } if ((extend_info || purpose != CIRCUIT_PURPOSE_C_GENERAL) && purpose != CIRCUIT_PURPOSE_TESTING && !onehop_tunnel) { /* see if there are appropriate circs available to cannibalize. */ /* XXX if we're planning to add a hop, perhaps we want to look for * internal circs rather than exit circs? -RD */ circ = circuit_find_to_cannibalize(purpose, extend_info, flags); if (circ) { uint8_t old_purpose = circ->base_.purpose; struct timeval old_timestamp_began = circ->base_.timestamp_began; log_info(LD_CIRC,"Cannibalizing circ '%s' for purpose %d (%s)", build_state_get_exit_nickname(circ->build_state), purpose, circuit_purpose_to_string(purpose)); if ((purpose == CIRCUIT_PURPOSE_S_CONNECT_REND || purpose == CIRCUIT_PURPOSE_C_INTRODUCING) && circ->path_state == PATH_STATE_BUILD_SUCCEEDED) { /* Path bias: Cannibalized rends pre-emptively count as a * successfully built but unused closed circuit. We don't * wait until the extend (or the close) because the rend * point could be malicious. * * Same deal goes for client side introductions. Clients * can be manipulated to connect repeatedly to them * (especially web clients). * * If we decide to probe the initial portion of these circs, * (up to the adversary's final hop), we need to remove this, * or somehow mark the circuit with a special path state. */ /* This must be called before the purpose change */ pathbias_check_close(circ, END_CIRC_REASON_FINISHED); } circuit_change_purpose(TO_CIRCUIT(circ), purpose); /* Reset the start date of this circ, else expire_building * will see it and think it's been trying to build since it * began. * * Technically, the code should reset this when the * create cell is finally sent, but we're close enough * here. */ tor_gettimeofday(&circ->base_.timestamp_began); control_event_circuit_cannibalized(circ, old_purpose, &old_timestamp_began); switch (purpose) { case CIRCUIT_PURPOSE_C_ESTABLISH_REND: case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* it's ready right now */ break; case CIRCUIT_PURPOSE_C_INTRODUCING: case CIRCUIT_PURPOSE_S_CONNECT_REND: case CIRCUIT_PURPOSE_C_GENERAL: /* need to add a new hop */ tor_assert(extend_info); if (circuit_extend_to_new_exit(circ, extend_info) < 0) return NULL; break; default: log_warn(LD_BUG, "unexpected purpose %d when cannibalizing a circ.", purpose); tor_fragile_assert(); return NULL; } return circ; } } if (did_circs_fail_last_period && n_circuit_failures > MAX_CIRCUIT_FAILURES) { /* too many failed circs in a row. don't try. */ // log_fn(LOG_INFO,"%d failures so far, not trying.",n_circuit_failures); return NULL; } /* try a circ. if it fails, circuit_mark_for_close will increment * n_circuit_failures */ return circuit_establish_circuit(purpose, extend_info, flags); } /** Record another failure at opening a general circuit. When we have * too many, we'll stop trying for the remainder of this minute. */ static void circuit_increment_failure_count(void) { ++n_circuit_failures; log_debug(LD_CIRC,"n_circuit_failures now %d.",n_circuit_failures); } /** Reset the failure count for opening general circuits. This means * we will try MAX_CIRCUIT_FAILURES times more (if necessary) before * stopping again. */ void circuit_reset_failure_count(int timeout) { if (timeout && n_circuit_failures > MAX_CIRCUIT_FAILURES) did_circs_fail_last_period = 1; else did_circs_fail_last_period = 0; n_circuit_failures = 0; } /** Find an open circ that we're happy to use for conn and return 1. If * there isn't one, and there isn't one on the way, launch one and return * 0. If it will never work, return -1. * * Write the found or in-progress or launched circ into *circp. */ static int circuit_get_open_circ_or_launch(entry_connection_t *conn, uint8_t desired_circuit_purpose, origin_circuit_t **circp) { origin_circuit_t *circ; int check_exit_policy; int need_uptime, need_internal; int want_onehop; const or_options_t *options = get_options(); tor_assert(conn); tor_assert(circp); tor_assert(ENTRY_TO_CONN(conn)->state == AP_CONN_STATE_CIRCUIT_WAIT); check_exit_policy = conn->socks_request->command == SOCKS_COMMAND_CONNECT && !conn->use_begindir && !connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn)); want_onehop = conn->want_onehop; need_uptime = !conn->want_onehop && !conn->use_begindir && smartlist_contains_int_as_string(options->LongLivedPorts, conn->socks_request->port); if (desired_circuit_purpose != CIRCUIT_PURPOSE_C_GENERAL) need_internal = 1; else if (conn->use_begindir || conn->want_onehop) need_internal = 1; else need_internal = 0; circ = circuit_get_best(conn, 1, desired_circuit_purpose, need_uptime, need_internal); if (circ) { *circp = circ; return 1; /* we're happy */ } if (!want_onehop && !router_have_minimum_dir_info()) { if (!connection_get_by_type(CONN_TYPE_DIR)) { int severity = LOG_NOTICE; /* FFFF if this is a tunneled directory fetch, don't yell * as loudly. the user doesn't even know it's happening. */ if (entry_list_is_constrained(options) && entries_known_but_down(options)) { log_fn(severity, LD_APP|LD_DIR, "Application request when we haven't used client functionality " "lately. Optimistically trying known %s again.", options->UseBridges ? "bridges" : "entrynodes"); entries_retry_all(options); } else if (!options->UseBridges || any_bridge_descriptors_known()) { log_fn(severity, LD_APP|LD_DIR, "Application request when we haven't used client functionality " "lately. Optimistically trying directory fetches again."); routerlist_retry_directory_downloads(time(NULL)); } } /* the stream will be dealt with when router_have_minimum_dir_info becomes * 1, or when all directory attempts fail and directory_all_unreachable() * kills it. */ return 0; } /* Do we need to check exit policy? */ if (check_exit_policy) { if (!conn->chosen_exit_name) { struct in_addr in; tor_addr_t addr, *addrp=NULL; if (tor_inet_aton(conn->socks_request->address, &in)) { tor_addr_from_in(&addr, &in); addrp = &addr; } if (router_exit_policy_all_nodes_reject(addrp, conn->socks_request->port, need_uptime)) { log_notice(LD_APP, "No Tor server allows exit to %s:%d. Rejecting.", safe_str_client(conn->socks_request->address), conn->socks_request->port); return -1; } } else { /* XXXX024 Duplicates checks in connection_ap_handshake_attach_circuit: * refactor into a single function? */ const node_t *node = node_get_by_nickname(conn->chosen_exit_name, 1); int opt = conn->chosen_exit_optional; if (node && !connection_ap_can_use_exit(conn, node)) { log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP, "Requested exit point '%s' is excluded or " "would refuse request. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); /* Try again. */ return circuit_get_open_circ_or_launch(conn, desired_circuit_purpose, circp); } return -1; } } } /* is one already on the way? */ circ = circuit_get_best(conn, 0, desired_circuit_purpose, need_uptime, need_internal); if (circ) log_debug(LD_CIRC, "one on the way!"); if (!circ) { extend_info_t *extend_info=NULL; uint8_t new_circ_purpose; const int n_pending = count_pending_general_client_circuits(); if (n_pending >= options->MaxClientCircuitsPending) { static ratelim_t delay_limit = RATELIM_INIT(10*60); char *m; if ((m = rate_limit_log(&delay_limit, approx_time()))) { log_notice(LD_APP, "We'd like to launch a circuit to handle a " "connection, but we already have %d general-purpose client " "circuits pending. Waiting until some finish.%s", n_pending, m); tor_free(m); } return 0; } if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) { /* need to pick an intro point */ rend_data_t *rend_data = ENTRY_TO_EDGE_CONN(conn)->rend_data; tor_assert(rend_data); extend_info = rend_client_get_random_intro(rend_data); if (!extend_info) { log_info(LD_REND, "No intro points for '%s': re-fetching service descriptor.", safe_str_client(rend_data->onion_address)); rend_client_refetch_v2_renddesc(rend_data); ENTRY_TO_CONN(conn)->state = AP_CONN_STATE_RENDDESC_WAIT; return 0; } log_info(LD_REND,"Chose %s as intro point for '%s'.", extend_info_describe(extend_info), safe_str_client(rend_data->onion_address)); } /* If we have specified a particular exit node for our * connection, then be sure to open a circuit to that exit node. */ if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_GENERAL) { if (conn->chosen_exit_name) { const node_t *r; int opt = conn->chosen_exit_optional; r = node_get_by_nickname(conn->chosen_exit_name, 1); if (r && node_has_descriptor(r)) { /* We might want to connect to an IPv6 bridge for loading descriptors so we use the preferred address rather than the primary. */ extend_info = extend_info_from_node(r, conn->want_onehop ? 1 : 0); } else { log_debug(LD_DIR, "considering %d, %s", want_onehop, conn->chosen_exit_name); if (want_onehop && conn->chosen_exit_name[0] == '$') { /* We're asking for a one-hop circuit to a router that * we don't have a routerinfo about. Make up an extend_info. */ char digest[DIGEST_LEN]; char *hexdigest = conn->chosen_exit_name+1; tor_addr_t addr; if (strlen(hexdigest) < HEX_DIGEST_LEN || base16_decode(digest,DIGEST_LEN,hexdigest,HEX_DIGEST_LEN)<0) { log_info(LD_DIR, "Broken exit digest on tunnel conn. Closing."); return -1; } if (tor_addr_parse(&addr, conn->socks_request->address) < 0) { log_info(LD_DIR, "Broken address %s on tunnel conn. Closing.", escaped_safe_str_client(conn->socks_request->address)); return -1; } extend_info = extend_info_new(conn->chosen_exit_name+1, digest, NULL, NULL, &addr, conn->socks_request->port); } else { /* We will need an onion key for the router, and we * don't have one. Refuse or relax requirements. */ log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP, "Requested exit point '%s' is not known. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); /* Try again with no requested exit */ return circuit_get_open_circ_or_launch(conn, desired_circuit_purpose, circp); } return -1; } } } } if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_REND_JOINED) new_circ_purpose = CIRCUIT_PURPOSE_C_ESTABLISH_REND; else if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) new_circ_purpose = CIRCUIT_PURPOSE_C_INTRODUCING; else new_circ_purpose = desired_circuit_purpose; if (options->Tor2webMode && (new_circ_purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND || new_circ_purpose == CIRCUIT_PURPOSE_C_INTRODUCING)) { want_onehop = 1; } { int flags = CIRCLAUNCH_NEED_CAPACITY; if (want_onehop) flags |= CIRCLAUNCH_ONEHOP_TUNNEL; if (need_uptime) flags |= CIRCLAUNCH_NEED_UPTIME; if (need_internal) flags |= CIRCLAUNCH_IS_INTERNAL; circ = circuit_launch_by_extend_info(new_circ_purpose, extend_info, flags); } extend_info_free(extend_info); if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_GENERAL) { /* We just caused a circuit to get built because of this stream. * If this stream has caused a _lot_ of circuits to be built, that's * a bad sign: we should tell the user. */ if (conn->num_circuits_launched < NUM_CIRCUITS_LAUNCHED_THRESHOLD && ++conn->num_circuits_launched == NUM_CIRCUITS_LAUNCHED_THRESHOLD) log_info(LD_CIRC, "The application request to %s:%d has launched " "%d circuits without finding one it likes.", escaped_safe_str_client(conn->socks_request->address), conn->socks_request->port, conn->num_circuits_launched); } else { /* help predict this next time */ rep_hist_note_used_internal(time(NULL), need_uptime, 1); if (circ) { /* write the service_id into circ */ circ->rend_data = rend_data_dup(ENTRY_TO_EDGE_CONN(conn)->rend_data); if (circ->base_.purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND && circ->base_.state == CIRCUIT_STATE_OPEN) rend_client_rendcirc_has_opened(circ); } } } /* endif (!circ) */ if (circ) { /* Mark the circuit with the isolation fields for this connection. * When the circuit arrives, we'll clear these flags: this is * just some internal bookkeeping to make sure that we have * launched enough circuits. */ connection_edge_update_circuit_isolation(conn, circ, 0); } else { log_info(LD_APP, "No safe circuit (purpose %d) ready for edge " "connection; delaying.", desired_circuit_purpose); } *circp = circ; return 0; } /** Return true iff crypt_path is one of the crypt_paths for * circ. */ static int cpath_is_on_circuit(origin_circuit_t *circ, crypt_path_t *crypt_path) { crypt_path_t *cpath, *cpath_next = NULL; for (cpath = circ->cpath; cpath_next != circ->cpath; cpath = cpath_next) { cpath_next = cpath->next; if (crypt_path == cpath) return 1; } return 0; } /** Return true iff client-side optimistic data is supported. */ static int optimistic_data_enabled(void) { const or_options_t *options = get_options(); if (options->OptimisticData < 0) { /* XXX023 consider having auto default to 1 rather than 0 before * the 0.2.3 branch goes stable. See bug 3617. -RD */ const int32_t enabled = networkstatus_get_param(NULL, "UseOptimisticData", 0, 0, 1); return (int)enabled; } return options->OptimisticData; } /** Attach the AP stream apconn to circ's linked list of * p_streams. Also set apconn's cpath_layer to cpath, or to the last * hop in circ's cpath if cpath is NULL. */ static void link_apconn_to_circ(entry_connection_t *apconn, origin_circuit_t *circ, crypt_path_t *cpath) { const node_t *exitnode; /* add it into the linked list of streams on this circuit */ log_debug(LD_APP|LD_CIRC, "attaching new conn to circ. n_circ_id %u.", (unsigned)circ->base_.n_circ_id); /* reset it, so we can measure circ timeouts */ ENTRY_TO_CONN(apconn)->timestamp_lastread = time(NULL); ENTRY_TO_EDGE_CONN(apconn)->next_stream = circ->p_streams; ENTRY_TO_EDGE_CONN(apconn)->on_circuit = TO_CIRCUIT(circ); /* assert_connection_ok(conn, time(NULL)); */ circ->p_streams = ENTRY_TO_EDGE_CONN(apconn); if (connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(apconn))) { /* We are attaching a stream to a rendezvous circuit. That means * that an attempt to connect to a hidden service just * succeeded. Tell rendclient.c. */ rend_client_note_connection_attempt_ended( ENTRY_TO_EDGE_CONN(apconn)->rend_data->onion_address); } if (cpath) { /* we were given one; use it */ tor_assert(cpath_is_on_circuit(circ, cpath)); } else { /* use the last hop in the circuit */ tor_assert(circ->cpath); tor_assert(circ->cpath->prev); tor_assert(circ->cpath->prev->state == CPATH_STATE_OPEN); cpath = circ->cpath->prev; } ENTRY_TO_EDGE_CONN(apconn)->cpath_layer = cpath; circ->isolation_any_streams_attached = 1; connection_edge_update_circuit_isolation(apconn, circ, 0); /* See if we can use optimistic data on this circuit */ if (cpath->extend_info && (exitnode = node_get_by_id(cpath->extend_info->identity_digest)) && exitnode->rs) { /* Okay; we know what exit node this is. */ if (optimistic_data_enabled() && circ->base_.purpose == CIRCUIT_PURPOSE_C_GENERAL && exitnode->rs->version_supports_optimistic_data) apconn->may_use_optimistic_data = 1; else apconn->may_use_optimistic_data = 0; log_info(LD_APP, "Looks like completed circuit to %s %s allow " "optimistic data for connection to %s", safe_str_client(node_describe(exitnode)), apconn->may_use_optimistic_data ? "does" : "doesn't", safe_str_client(apconn->socks_request->address)); } } /** Return true iff address is matched by one of the entries in * TrackHostExits. */ int hostname_in_track_host_exits(const or_options_t *options, const char *address) { if (!options->TrackHostExits) return 0; SMARTLIST_FOREACH_BEGIN(options->TrackHostExits, const char *, cp) { if (cp[0] == '.') { /* match end */ if (cp[1] == '\0' || !strcasecmpend(address, cp) || !strcasecmp(address, &cp[1])) return 1; } else if (strcasecmp(cp, address) == 0) { return 1; } } SMARTLIST_FOREACH_END(cp); return 0; } /** If an exit wasn't explicitly specified for conn, consider saving * the exit that we *did* choose for use by future connections to * conn's destination. */ static void consider_recording_trackhost(const entry_connection_t *conn, const origin_circuit_t *circ) { const or_options_t *options = get_options(); char *new_address = NULL; char fp[HEX_DIGEST_LEN+1]; /* Search the addressmap for this conn's destination. */ /* If he's not in the address map.. */ if (!options->TrackHostExits || addressmap_have_mapping(conn->socks_request->address, options->TrackHostExitsExpire)) return; /* nothing to track, or already mapped */ if (!hostname_in_track_host_exits(options, conn->socks_request->address) || !circ->build_state->chosen_exit) return; /* write down the fingerprint of the chosen exit, not the nickname, * because the chosen exit might not be named. */ base16_encode(fp, sizeof(fp), circ->build_state->chosen_exit->identity_digest, DIGEST_LEN); /* Add this exit/hostname pair to the addressmap. */ tor_asprintf(&new_address, "%s.%s.exit", conn->socks_request->address, fp); addressmap_register(conn->socks_request->address, new_address, time(NULL) + options->TrackHostExitsExpire, ADDRMAPSRC_TRACKEXIT, 0, 0); } /** Attempt to attach the connection conn to circ, and send a * begin or resolve cell as appropriate. Return values are as for * connection_ap_handshake_attach_circuit. The stream will exit from the hop * indicated by cpath, or from the last hop in circ's cpath if * cpath is NULL. */ int connection_ap_handshake_attach_chosen_circuit(entry_connection_t *conn, origin_circuit_t *circ, crypt_path_t *cpath) { connection_t *base_conn = ENTRY_TO_CONN(conn); tor_assert(conn); tor_assert(base_conn->state == AP_CONN_STATE_CIRCUIT_WAIT || base_conn->state == AP_CONN_STATE_CONTROLLER_WAIT); tor_assert(conn->socks_request); tor_assert(circ); tor_assert(circ->base_.state == CIRCUIT_STATE_OPEN); base_conn->state = AP_CONN_STATE_CIRCUIT_WAIT; if (!circ->base_.timestamp_dirty) circ->base_.timestamp_dirty = time(NULL); pathbias_count_use_attempt(circ); link_apconn_to_circ(conn, circ, cpath); tor_assert(conn->socks_request); if (conn->socks_request->command == SOCKS_COMMAND_CONNECT) { if (!conn->use_begindir) consider_recording_trackhost(conn, circ); if (connection_ap_handshake_send_begin(conn) < 0) return -1; } else { if (connection_ap_handshake_send_resolve(conn) < 0) return -1; } return 1; } /** Try to find a safe live circuit for CONN_TYPE_AP connection conn. If * we don't find one: if conn cannot be handled by any known nodes, * warn and return -1 (conn needs to die, and is maybe already marked); * else launch new circuit (if necessary) and return 0. * Otherwise, associate conn with a safe live circuit, do the * right next step, and return 1. */ /* XXXX this function should mark for close whenever it returns -1; * its callers shouldn't have to worry about that. */ int connection_ap_handshake_attach_circuit(entry_connection_t *conn) { connection_t *base_conn = ENTRY_TO_CONN(conn); int retval; int conn_age; int want_onehop; tor_assert(conn); tor_assert(base_conn->state == AP_CONN_STATE_CIRCUIT_WAIT); tor_assert(conn->socks_request); want_onehop = conn->want_onehop; conn_age = (int)(time(NULL) - base_conn->timestamp_created); if (conn_age >= get_options()->SocksTimeout) { int severity = (tor_addr_is_null(&base_conn->addr) && !base_conn->port) ? LOG_INFO : LOG_NOTICE; log_fn(severity, LD_APP, "Tried for %d seconds to get a connection to %s:%d. Giving up.", conn_age, safe_str_client(conn->socks_request->address), conn->socks_request->port); return -1; } if (!connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn))) { /* we're a general conn */ origin_circuit_t *circ=NULL; if (conn->chosen_exit_name) { const node_t *node = node_get_by_nickname(conn->chosen_exit_name, 1); int opt = conn->chosen_exit_optional; if (!node && !want_onehop) { /* We ran into this warning when trying to extend a circuit to a * hidden service directory for which we didn't have a router * descriptor. See flyspray task 767 for more details. We should * keep this in mind when deciding to use BEGIN_DIR cells for other * directory requests as well. -KL*/ log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP, "Requested exit point '%s' is not known. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); return 0; } return -1; } if (node && !connection_ap_can_use_exit(conn, node)) { log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP, "Requested exit point '%s' is excluded or " "would refuse request. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); return 0; } return -1; } } /* find the circuit that we should use, if there is one. */ retval = circuit_get_open_circ_or_launch( conn, CIRCUIT_PURPOSE_C_GENERAL, &circ); if (retval < 1) // XXX023 if we totally fail, this still returns 0 -RD return retval; log_debug(LD_APP|LD_CIRC, "Attaching apconn to circ %u (stream %d sec old).", (unsigned)circ->base_.n_circ_id, conn_age); /* print the circ's path, so people can figure out which circs are * sucking. */ circuit_log_path(LOG_INFO,LD_APP|LD_CIRC,circ); /* We have found a suitable circuit for our conn. Hurray. */ return connection_ap_handshake_attach_chosen_circuit(conn, circ, NULL); } else { /* we're a rendezvous conn */ origin_circuit_t *rendcirc=NULL, *introcirc=NULL; tor_assert(!ENTRY_TO_EDGE_CONN(conn)->cpath_layer); /* start by finding a rendezvous circuit for us */ retval = circuit_get_open_circ_or_launch( conn, CIRCUIT_PURPOSE_C_REND_JOINED, &rendcirc); if (retval < 0) return -1; /* failed */ if (retval > 0) { tor_assert(rendcirc); /* one is already established, attach */ log_info(LD_REND, "rend joined circ %d already here. attaching. " "(stream %d sec old)", (unsigned)rendcirc->base_.n_circ_id, conn_age); /* Mark rendezvous circuits as 'newly dirty' every time you use * them, since the process of rebuilding a rendezvous circ is so * expensive. There is a tradeoff between linkability and * feasibility, at this point. */ rendcirc->base_.timestamp_dirty = time(NULL); /* We've also attempted to use them. If they fail, we need to * probe them for path bias */ pathbias_count_use_attempt(rendcirc); link_apconn_to_circ(conn, rendcirc, NULL); if (connection_ap_handshake_send_begin(conn) < 0) return 0; /* already marked, let them fade away */ return 1; } if (rendcirc && (rendcirc->base_.purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED)) { log_info(LD_REND, "pending-join circ %u already here, with intro ack. " "Stalling. (stream %d sec old)", (unsigned)rendcirc->base_.n_circ_id, conn_age); return 0; } /* it's on its way. find an intro circ. */ retval = circuit_get_open_circ_or_launch( conn, CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT, &introcirc); if (retval < 0) return -1; /* failed */ if (retval > 0) { /* one has already sent the intro. keep waiting. */ tor_assert(introcirc); log_info(LD_REND, "Intro circ %u present and awaiting ack (rend %u). " "Stalling. (stream %d sec old)", (unsigned)introcirc->base_.n_circ_id, rendcirc ? (unsigned)rendcirc->base_.n_circ_id : 0, conn_age); return 0; } /* now rendcirc and introcirc are each either undefined or not finished */ if (rendcirc && introcirc && rendcirc->base_.purpose == CIRCUIT_PURPOSE_C_REND_READY) { log_info(LD_REND, "ready rend circ %u already here (no intro-ack yet on " "intro %u). (stream %d sec old)", (unsigned)rendcirc->base_.n_circ_id, (unsigned)introcirc->base_.n_circ_id, conn_age); tor_assert(introcirc->base_.purpose == CIRCUIT_PURPOSE_C_INTRODUCING); if (introcirc->base_.state == CIRCUIT_STATE_OPEN) { log_info(LD_REND,"found open intro circ %u (rend %u); sending " "introduction. (stream %d sec old)", (unsigned)introcirc->base_.n_circ_id, (unsigned)rendcirc->base_.n_circ_id, conn_age); switch (rend_client_send_introduction(introcirc, rendcirc)) { case 0: /* success */ rendcirc->base_.timestamp_dirty = time(NULL); introcirc->base_.timestamp_dirty = time(NULL); pathbias_count_use_attempt(introcirc); pathbias_count_use_attempt(rendcirc); assert_circuit_ok(TO_CIRCUIT(rendcirc)); assert_circuit_ok(TO_CIRCUIT(introcirc)); return 0; case -1: /* transient error */ return 0; case -2: /* permanent error */ return -1; default: /* oops */ tor_fragile_assert(); return -1; } } } log_info(LD_REND, "Intro (%u) and rend (%u) circs are not both ready. " "Stalling conn. (%d sec old)", introcirc ? (unsigned)introcirc->base_.n_circ_id : 0, rendcirc ? (unsigned)rendcirc->base_.n_circ_id : 0, conn_age); return 0; } } /** Change circ's purpose to new_purpose. */ void circuit_change_purpose(circuit_t *circ, uint8_t new_purpose) { uint8_t old_purpose; /* Don't allow an OR circ to become an origin circ or vice versa. */ tor_assert(!!(CIRCUIT_IS_ORIGIN(circ)) == !!(CIRCUIT_PURPOSE_IS_ORIGIN(new_purpose))); if (circ->purpose == new_purpose) return; if (CIRCUIT_IS_ORIGIN(circ)) { char old_purpose_desc[80] = ""; strncpy(old_purpose_desc, circuit_purpose_to_string(circ->purpose), 80-1); old_purpose_desc[80-1] = '\0'; log_debug(LD_CIRC, "changing purpose of origin circ %d " "from \"%s\" (%d) to \"%s\" (%d)", TO_ORIGIN_CIRCUIT(circ)->global_identifier, old_purpose_desc, circ->purpose, circuit_purpose_to_string(new_purpose), new_purpose); } old_purpose = circ->purpose; circ->purpose = new_purpose; if (CIRCUIT_IS_ORIGIN(circ)) { control_event_circuit_purpose_changed(TO_ORIGIN_CIRCUIT(circ), old_purpose); } } /** Mark circ so that no more connections can be attached to it. */ void mark_circuit_unusable_for_new_conns(origin_circuit_t *circ) { const or_options_t *options = get_options(); tor_assert(circ); /* XXXX025 This is a kludge; we're only keeping it around in case there's * something that doesn't check unusable_for_new_conns, and to avoid * deeper refactoring of our expiration logic. */ if (! circ->base_.timestamp_dirty) circ->base_.timestamp_dirty = approx_time(); if (options->MaxCircuitDirtiness >= circ->base_.timestamp_dirty) circ->base_.timestamp_dirty = 1; /* prevent underflow */ else circ->base_.timestamp_dirty -= options->MaxCircuitDirtiness; circ->unusable_for_new_conns = 1; }