/* Copyright 2001 Matej Pfajfar. * Copyright 2001-2004 Roger Dingledine. * Copyright 2004 Roger Dingledine, Nick Mathewson. */ /* See LICENSE for licensing information */ /* $Id$ */ const char circuituse_c_id[] = "$Id$"; /** * \file circuituse.c * \brief Launch the right sort of circuits, attach streams to them. **/ #include "or.h" /** Longest time to wait for a circuit before closing an AP connection */ #define CONN_AP_MAX_ATTACH_DELAY 59 /********* START VARIABLES **********/ extern circuit_t *global_circuitlist; /* from circuitlist.c */ extern int has_fetched_directory; /* from main.c */ /********* END VARIABLES ************/ static void circuit_expire_old_circuits(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(circuit_t *circ, connection_t *conn, int must_be_open, uint8_t purpose, time_t now) { routerinfo_t *exitrouter; tor_assert(circ); tor_assert(conn); tor_assert(conn->socks_request); if (!CIRCUIT_IS_ORIGIN(circ)) return 0; /* this circ doesn't start at us */ if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn)) 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 (purpose == CIRCUIT_PURPOSE_C_GENERAL) if (circ->timestamp_dirty && circ->timestamp_dirty+get_options()->MaxCircuitDirtiness <= now) 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. */ exitrouter = router_get_by_digest(circ->build_state->chosen_exit_digest); if (!exitrouter) { log_fn(LOG_INFO,"Skipping broken circ (exit router vanished)"); return 0; /* this circuit is screwed and doesn't know it yet */ } if (!circ->build_state->need_uptime && smartlist_string_num_isin(get_options()->LongLivedPorts, conn->socks_request->port)) return 0; if (purpose == CIRCUIT_PURPOSE_C_GENERAL) { if (!connection_ap_can_use_exit(conn, exitrouter)) { /* can't exit from this router */ return 0; } } else { /* not general */ if (rend_cmp_service_ids(conn->rend_query, circ->rend_query)) { /* this circ is not for this conn */ return 0; } } return 1; } /* Return 1 if circuit a is better than circuit b for * purpose, and return 0 otherwise. Used by circuit_get_best. */ static int circuit_is_better(circuit_t *a, circuit_t *b, uint8_t purpose) { 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 || b->build_state->is_internal || a->timestamp_created > b->timestamp_created) 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; } 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 circuit_t * circuit_get_best(connection_t *conn, int must_be_open, uint8_t purpose) { circuit_t *circ, *best=NULL; time_t now = time(NULL); tor_assert(conn); tor_assert(purpose == CIRCUIT_PURPOSE_C_GENERAL || purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT || purpose == CIRCUIT_PURPOSE_C_REND_JOINED); for (circ=global_circuitlist;circ;circ = circ->next) { if (!circuit_is_acceptable(circ,conn,must_be_open,purpose,now)) 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(circ,best,purpose)) best = circ; } return best; } /** If we find a circuit that isn't open yet and was born this many * seconds ago, then assume something went wrong, and cull it. */ #define MIN_SECONDS_BEFORE_EXPIRING_CIRC 30 /** Close all circuits that start at us, aren't open, and were born * at least MIN_SECONDS_BEFORE_EXPIRING_CIRC seconds ago. */ void circuit_expire_building(time_t now) { circuit_t *victim, *circ = global_circuitlist; while (circ) { victim = circ; circ = circ->next; if (!CIRCUIT_IS_ORIGIN(victim)) continue; /* didn't originate here */ if (victim->marked_for_close) continue; /* don't mess with marked circs */ if (victim->timestamp_created + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now) continue; /* it's young still, don't mess with it */ #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 purp %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 purp %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 || victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND || victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING || victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO || /* it's a rend_ready circ, but it's already picked a query */ (victim->purpose == CIRCUIT_PURPOSE_C_REND_READY && victim->rend_query[0]) || /* c_rend_ready circs measure age since timestamp_dirty, * because that's set when they switch purposes */ /* rend and intro circs become dirty each time they * make an introduction attempt. so timestamp_dirty * will reflect the time since the last attempt. */ ((victim->purpose == CIRCUIT_PURPOSE_C_REND_READY || victim->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED || victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) && victim->timestamp_dirty + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now)) { if (victim->n_conn) log_fn(LOG_INFO,"Abandoning circ %s:%d:%d (state %d:%s, purpose %d)", victim->n_conn->address, victim->n_port, victim->n_circ_id, victim->state, circuit_state_to_string[victim->state], victim->purpose); else log_fn(LOG_INFO,"Abandoning circ %d (state %d:%s, purpose %d)", victim->n_circ_id, victim->state, circuit_state_to_string[victim->state], victim->purpose); circuit_log_path(LOG_INFO,victim); circuit_mark_for_close(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, 2)) { // log_fn(LOG_DEBUG,"Port %d is already being handled; removing.", port); smartlist_del(needed_ports, i--); tor_free(port); } else { log_fn(LOG_DEBUG,"Port %d is not handled.", *port); } } } /** Return 1 if at least min general-purpose circuits will have * an acceptable exit node for conn if conn is defined, else for "*:port". * Else return 0. */ int circuit_stream_is_being_handled(connection_t *conn, uint16_t port, int min) { circuit_t *circ; routerinfo_t *exitrouter; int num=0; time_t now = time(NULL); int need_uptime = smartlist_string_num_isin(get_options()->LongLivedPorts, conn ? conn->socks_request->port : port); for (circ=global_circuitlist;circ;circ = circ->next) { 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)) { exitrouter = router_get_by_digest(circ->build_state->chosen_exit_digest); if (exitrouter && (!need_uptime || circ->build_state->need_uptime) && ((conn && connection_ap_can_use_exit(conn, exitrouter)) || (!conn && router_compare_addr_to_addr_policy(0, port, exitrouter->exit_policy) != ADDR_POLICY_REJECTED))) { if (++num >= min) return 1; } } } return 0; } /** Don't keep more than 10 unused open circuits around. */ #define MAX_UNUSED_OPEN_CIRCUITS 10 /** 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 if we have too many, close the not-so-useful ones. */ 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; int need_ports, need_hidserv; time_t now = time(NULL); /* check if we know of a port that's been requested recently * and no circuit is currently available that can handle it. */ need_ports = !circuit_all_predicted_ports_handled(now, &port_needs_uptime, &port_needs_capacity); need_hidserv = rep_hist_get_predicted_hidserv(now, &hidserv_needs_uptime, &hidserv_needs_capacity); for (circ=global_circuitlist;circ;circ = circ->next) { 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 */ num++; if (circ->build_state->is_internal) num_internal++; if (circ->build_state->need_uptime && circ->build_state->is_internal) num_uptime_internal++; } if (num < MAX_UNUSED_OPEN_CIRCUITS) { /* perhaps we want another */ if (need_ports) { log_fn(LOG_INFO,"Have %d clean circs (%d internal), need another exit circ.", num, num_internal); circuit_launch_by_identity(CIRCUIT_PURPOSE_C_GENERAL, NULL, port_needs_uptime, port_needs_capacity, 0); } else if (need_hidserv && ((num_uptime_internal<2 && hidserv_needs_uptime) || num_internal<2)) { log_fn(LOG_INFO,"Have %d clean circs (%d uptime-internal, %d internal)," " need another hidserv circ.", num, num_uptime_internal, num_internal); circuit_launch_by_identity(CIRCUIT_PURPOSE_C_GENERAL, NULL, hidserv_needs_uptime, hidserv_needs_capacity, 1); } } } /** Build a new test circuit every 5 minutes */ #define TESTING_CIRCUIT_INTERVAL 300 /** This function is called once a second. 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 long time_to_new_circuit = 0; /* launch a new circ for any pending streams that need one */ connection_ap_attach_pending(); /* make sure any hidden services have enough intro points */ if (has_fetched_directory) rend_services_introduce(); if (time_to_new_circuit < now) { circuit_reset_failure_count(1); time_to_new_circuit = now + get_options()->NewCircuitPeriod; if (proxy_mode(get_options())) addressmap_clean(now); circuit_expire_old_circuits(); #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_created + TESTING_CIRCUIT_INTERVAL < now) { log_fn(LOG_INFO,"Creating a new testing circuit."); circuit_launch_by_identity(CIRCUIT_PURPOSE_C_GENERAL, NULL, 0, 0, 0); } #endif } 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, connection_t *conn) { connection_t *prevconn; tor_assert(circ); tor_assert(conn); conn->cpath_layer = NULL; /* make sure we don't keep a stale pointer */ if (conn == circ->p_streams) { circ->p_streams = conn->next_stream; return; } if (conn == circ->n_streams) { circ->n_streams = conn->next_stream; return; } if (conn == circ->resolving_streams) { circ->resolving_streams = conn->next_stream; return; } for (prevconn = 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; } for (prevconn = 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 = 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_fn(LOG_ERR,"edge conn not in circuit's list?"); tor_assert(0); /* should never get here */ } /** Notify the global circuit list that conn is about to be * removed and then freed. * * If it's an OR conn, then mark-for-close all the circuits that use * that conn. * * If it's an edge conn, then detach it from its circ, so we don't * try to reference it later. */ void circuit_about_to_close_connection(connection_t *conn) { /* currently, we assume it's too late to flush conn's buf here. * down the road, maybe we'll consider that eof doesn't mean can't-write */ circuit_t *circ; switch (conn->type) { case CONN_TYPE_OR: if (conn->state != OR_CONN_STATE_OPEN) { /* Inform any pending (not attached) circs that they should give up. */ circuit_n_conn_done(conn, 0); } /* Now close all the attached circuits on it. */ while ((circ = circuit_get_by_conn(conn))) { if (circ->n_conn == conn) /* it's closing in front of us */ circ->n_conn = NULL; if (circ->p_conn == conn) /* it's closing behind us */ circ->p_conn = NULL; circuit_mark_for_close(circ); } return; case CONN_TYPE_AP: case CONN_TYPE_EXIT: /* It's an edge conn. Need to remove it from the linked list of * conn's for this circuit. Confirm that 'end' relay command has * been sent. But don't kill the circuit. */ circ = circuit_get_by_conn(conn); if (!circ) return; circuit_detach_stream(circ, conn); } /* end switch */ } /** Find each circuit that has been dirty for too long, and has * no streams on it: mark it for close. */ static void circuit_expire_old_circuits(void) { circuit_t *circ; time_t now = time(NULL); for (circ = global_circuitlist; circ; circ = circ->next) { if (circ->marked_for_close) 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 && CIRCUIT_IS_ORIGIN(circ) && !circ->p_streams /* nothing attached */ ) { log_fn(LOG_DEBUG,"Closing n_circ_id %d (dirty %d secs ago, purp %d)",circ->n_circ_id, (int)(now - circ->timestamp_dirty), circ->purpose); /* (only general and purpose_c circs can get dirty) */ tor_assert(!circ->n_streams); tor_assert(circ->purpose <= CIRCUIT_PURPOSE_C_REND_JOINED); circuit_mark_for_close(circ); } else if (!circ->timestamp_dirty && CIRCUIT_IS_ORIGIN(circ) && circ->state == CIRCUIT_STATE_OPEN && circ->purpose == CIRCUIT_PURPOSE_C_GENERAL) { #define CIRCUIT_UNUSED_CIRC_TIMEOUT 3600 /* an hour */ if (circ->timestamp_created + CIRCUIT_UNUSED_CIRC_TIMEOUT < now) { log_fn(LOG_DEBUG,"Closing circuit that has been unused for %d seconds.", (int)(now - circ->timestamp_created)); circuit_mark_for_close(circ); } } } } /** A testing circuit has completed. Take whatever stats we want. */ static void circuit_testing_opened(circuit_t *circ) { /* For now, we only use testing circuits to see if our ORPort is reachable. But we remember reachability in onionskin_answer(), so there's no need to record anything here. Just close the circ. */ circuit_mark_for_close(circ); } /** A testing circuit has failed to build. Take whatever stats we want. */ static void circuit_testing_failed(circuit_t *circ, int at_last_hop) { routerinfo_t *me = router_get_my_routerinfo(); if (!at_last_hop) circuit_launch_by_identity(CIRCUIT_PURPOSE_TESTING, me->identity_digest, 0, 0, 1); else log_fn(LOG_INFO,"Our testing circuit (to see if your ORPort is reachable) has failed. I'll try again later."); } /** 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(circuit_t *circ) { control_event_circuit_status(circ, CIRC_EVENT_BUILT); switch (circ->purpose) { case CIRCUIT_PURPOSE_C_ESTABLISH_REND: rend_client_rendcirc_has_opened(circ); connection_ap_attach_pending(); 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. */ connection_ap_attach_pending(); 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: log_fn(LOG_ERR,"unhandled purpose %d",circ->purpose); tor_assert(0); } } /*~ Called whenever a circuit could not be successfully built. */ void circuit_build_failed(circuit_t *circ) { /* 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; } switch (circ->purpose) { case CIRCUIT_PURPOSE_C_GENERAL: if (circ->state != CIRCUIT_STATE_OPEN) { /* If we never built the circuit, note it as a failure. */ /* Note that we can't just check circ->cpath here, because if * circuit-building failed immediately, it won't be set yet. */ circuit_increment_failure_count(); } 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->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 */ if (circ->state != CIRCUIT_STATE_OPEN) { 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 */ if (failed_at_last_hop) { log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s. Sucks to be Alice.", circ->build_state->chosen_exit_name); } else { log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s, because an earlier node failed.", circ->build_state->chosen_exit_name); rend_service_relaunch_rendezvous(circ); } break; default: /* Other cases are impossible, since this function is only called with * unbuilt circuits. */ tor_assert(0); } } /** Number of consecutive failures so far; should only be touched by * circuit_launch_new and circuit_*_failure_count. */ static int n_circuit_failures = 0; 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 circuit_t * circuit_launch_by_identity(uint8_t purpose, const char *exit_digest, int need_uptime, int need_capacity, int internal) { circuit_t *circ; if (!has_fetched_directory) { log_fn(LOG_DEBUG,"Haven't fetched directory yet; canceling circuit launch."); return NULL; } if (purpose != CIRCUIT_PURPOSE_C_GENERAL && purpose != CIRCUIT_PURPOSE_TESTING) { /* see if there are appropriate circs available to cannibalize. */ if ((circ = circuit_get_clean_open(CIRCUIT_PURPOSE_C_GENERAL, need_uptime, need_capacity, internal))) { log_fn(LOG_INFO,"Cannibalizing circ '%s' for purpose %d", circ->build_state->chosen_exit_name, purpose); circ->purpose = purpose; /* reset the birth date of this circ, else expire_building * will see it and think it's been trying to build since it * began. */ circ->timestamp_created = time(NULL); switch (purpose) { case CIRCUIT_PURPOSE_C_ESTABLISH_REND: /* it's ready right now */ /* XXX should we call control_event_circuit_status() here? */ rend_client_rendcirc_has_opened(circ); break; case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* it's ready right now */ rend_service_intro_has_opened(circ); break; case CIRCUIT_PURPOSE_C_INTRODUCING: case CIRCUIT_PURPOSE_S_CONNECT_REND: /* need to add a new hop */ tor_assert(exit_digest); if (circuit_append_new_hop(circ, NULL, exit_digest) < 0) return NULL; break; default: log_fn(LOG_WARN,"Bug: unexpected purpose %d when cannibalizing a general circ.", purpose); #ifdef TOR_FRAGILE tor_assert(0); #endif 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, exit_digest, need_uptime, need_capacity, internal); } /** Launch a new circuit and return a pointer to it. Return NULL if you failed. */ circuit_t * circuit_launch_by_nickname(uint8_t purpose, const char *exit_nickname, int need_uptime, int need_capacity, int internal) { const char *digest = NULL; if (exit_nickname) { routerinfo_t *r = router_get_by_nickname(exit_nickname); if (!r) { log_fn(LOG_WARN, "No such OR as '%s'", exit_nickname); return NULL; } digest = r->identity_digest; } return circuit_launch_by_identity(purpose, digest, need_uptime, need_capacity, internal); } /** 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_fn(LOG_DEBUG,"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 with: 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(connection_t *conn, uint8_t desired_circuit_purpose, circuit_t **circp) { circuit_t *circ; int is_resolve; int need_uptime; tor_assert(conn); tor_assert(circp); tor_assert(conn->state == AP_CONN_STATE_CIRCUIT_WAIT); is_resolve = conn->socks_request->command == SOCKS_COMMAND_RESOLVE; circ = circuit_get_best(conn, 1, desired_circuit_purpose); if (circ) { *circp = circ; return 1; /* we're happy */ } if (!has_fetched_directory) { if (!connection_get_by_type(CONN_TYPE_DIR)) { log_fn(LOG_NOTICE,"Application request when we're believed to be offline. Optimistically trying again."); directory_get_from_dirserver(DIR_PURPOSE_FETCH_DIR, NULL, 1); } /* the stream will be dealt with when has_fetched_directory becomes * 1, or when all directory attempts fail and directory_all_unreachable() * kills it. */ return 0; } need_uptime = smartlist_string_num_isin(get_options()->LongLivedPorts, conn->socks_request->port); /* Do we need to check exit policy? */ if (!is_resolve && !connection_edge_is_rendezvous_stream(conn)) { struct in_addr in; uint32_t addr = 0; if (tor_inet_aton(conn->socks_request->address, &in)) addr = ntohl(in.s_addr); if (router_exit_policy_all_routers_reject(addr, conn->socks_request->port, need_uptime)) { log_fn(LOG_NOTICE,"No Tor server exists that allows exit to %s:%d. Rejecting.", conn->socks_request->address, conn->socks_request->port); return -1; } } /* is one already on the way? */ circ = circuit_get_best(conn, 0, desired_circuit_purpose); if (!circ) { char *exitname=NULL; uint8_t new_circ_purpose; int is_internal; if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) { /* need to pick an intro point */ try_an_intro_point: exitname = rend_client_get_random_intro(conn->rend_query); if (!exitname) { log_fn(LOG_INFO,"No intro points for '%s': refetching service descriptor.", conn->rend_query); rend_client_refetch_renddesc(conn->rend_query); conn->state = AP_CONN_STATE_RENDDESC_WAIT; return 0; } if (!router_get_by_nickname(exitname)) { log_fn(LOG_NOTICE,"Advertised intro point '%s' is not recognized for '%s'. Skipping over.", exitname, conn->rend_query); rend_client_remove_intro_point(exitname, conn->rend_query); tor_free(exitname); goto try_an_intro_point; } log_fn(LOG_INFO,"Chose %s as intro point for %s.", exitname, conn->rend_query); } /* 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) { exitname = tor_strdup(conn->chosen_exit_name); if (!router_get_by_nickname(exitname)) { log_fn(LOG_NOTICE,"Requested exit point '%s' is not known. Closing.", exitname); tor_free(exitname); 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; is_internal = (new_circ_purpose != CIRCUIT_PURPOSE_C_GENERAL || is_resolve); circ = circuit_launch_by_nickname(new_circ_purpose, exitname, need_uptime, 1, is_internal); tor_free(exitname); if (desired_circuit_purpose != CIRCUIT_PURPOSE_C_GENERAL) { /* help predict this next time */ rep_hist_note_used_hidserv(time(NULL), need_uptime, 1); if (circ) { /* write the service_id into circ */ strlcpy(circ->rend_query, conn->rend_query, sizeof(circ->rend_query)); } } } if (!circ) log_fn(LOG_INFO,"No safe circuit (purpose %d) ready for edge connection; delaying.", desired_circuit_purpose); *circp = circ; return 0; } /** Attach the AP stream apconn to circ's linked list of * p_streams. Also set apconn's cpath_layer to the last hop in * circ's cpath. */ static void link_apconn_to_circ(connection_t *apconn, circuit_t *circ) { /* add it into the linked list of streams on this circuit */ log_fn(LOG_DEBUG,"attaching new conn to circ. n_circ_id %d.", circ->n_circ_id); apconn->timestamp_lastread = time(NULL); /* reset it, so we can measure circ timeouts */ apconn->next_stream = circ->p_streams; /* assert_connection_ok(conn, time(NULL)); */ circ->p_streams = apconn; tor_assert(CIRCUIT_IS_ORIGIN(circ)); tor_assert(circ->cpath); tor_assert(circ->cpath->prev); tor_assert(circ->cpath->prev->state == CPATH_STATE_OPEN); apconn->cpath_layer = circ->cpath->prev; } /** If an exit wasn't specifically chosen, save the history for future * use */ static void consider_recording_trackhost(connection_t *conn, circuit_t *circ) { int found_needle = 0; char *str; or_options_t *options = get_options(); size_t len; char *new_address; /* Search the addressmap for this conn's destination. */ /* If he's not in the address map.. */ if (!options->TrackHostExits || addressmap_already_mapped(conn->socks_request->address)) return; /* nothing to track, or already mapped */ SMARTLIST_FOREACH(options->TrackHostExits, const char *, cp, { if (cp[0] == '.') { /* match end */ /* XXX strstr is probably really bad here */ if ((str = strstr(conn->socks_request->address, &cp[1]))) { if (str == conn->socks_request->address || strcmp(str, &cp[1]) == 0) { found_needle = 1; } } } else if (strcmp(cp, conn->socks_request->address) == 0) { found_needle = 1; } }); if (!found_needle) return; /* Add this exit/hostname pair to the addressmap. */ len = strlen(conn->socks_request->address) + 1 /* '.' */ + strlen(circ->build_state->chosen_exit_name) + 1 /* '.' */ + strlen("exit") + 1 /* '\0' */; new_address = tor_malloc(len); tor_snprintf(new_address, len, "%s.%s.exit", conn->socks_request->address, circ->build_state->chosen_exit_name); addressmap_register(conn->socks_request->address, new_address, time(NULL) + options->TrackHostExitsExpire); } /* DOCDOC. Return as for connection_ap_handshake_attach_chosen_circuit. */ int connection_ap_handshake_attach_chosen_circuit(connection_t *conn, circuit_t *circ) { tor_assert(conn); tor_assert(conn->type == CONN_TYPE_AP); tor_assert(conn->state == AP_CONN_STATE_CIRCUIT_WAIT || conn->state == AP_CONN_STATE_CONTROLLER_WAIT); tor_assert(conn->socks_request); tor_assert(circ); conn->state = AP_CONN_STATE_CIRCUIT_WAIT; if (!circ->timestamp_dirty) circ->timestamp_dirty = time(NULL); link_apconn_to_circ(conn, circ); tor_assert(conn->socks_request); if (conn->socks_request->command == SOCKS_COMMAND_CONNECT) { consider_recording_trackhost(conn, circ); connection_ap_handshake_send_begin(conn, circ); } else { connection_ap_handshake_send_resolve(conn, circ); } 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); * 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. */ int connection_ap_handshake_attach_circuit(connection_t *conn) { int retval; int conn_age; tor_assert(conn); tor_assert(conn->type == CONN_TYPE_AP); tor_assert(conn->state == AP_CONN_STATE_CIRCUIT_WAIT); tor_assert(conn->socks_request); conn_age = time(NULL) - conn->timestamp_created; if (conn_age > CONN_AP_MAX_ATTACH_DELAY) { log_fn(LOG_NOTICE,"Giving up on unattached conn (%d sec old).", conn_age); return -1; } if (!connection_edge_is_rendezvous_stream(conn)) { /* we're a general conn */ circuit_t *circ=NULL; if (conn->chosen_exit_name) { routerinfo_t *router = router_get_by_nickname(conn->chosen_exit_name); if (!router) { log_fn(LOG_WARN,"Requested exit point '%s' is not known. Closing.", conn->chosen_exit_name); return -1; } if (!connection_ap_can_use_exit(conn, router)) { log_fn(LOG_WARN, "Requested exit point '%s' would refuse request. Closing.", conn->chosen_exit_name); 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) return retval; log_fn(LOG_DEBUG,"Attaching apconn to circ %d (stream %d sec old).", circ->n_circ_id, conn_age); /* here, print the circ's path. so people can figure out which circs are sucking. */ circuit_log_path(LOG_INFO,circ); /* We have found a suitable circuit for our conn. Hurray. */ return connection_ap_handshake_attach_chosen_circuit(conn, circ); } else { /* we're a rendezvous conn */ circuit_t *rendcirc=NULL, *introcirc=NULL; tor_assert(!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_fn(LOG_INFO,"rend joined circ %d already here. attaching. (stream %d sec old)", rendcirc->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 tradeoffs between linkability and * feasibility, at this point. */ rendcirc->timestamp_dirty = time(NULL); link_apconn_to_circ(conn, rendcirc); if (connection_ap_handshake_send_begin(conn, rendcirc) < 0) return 0; /* already marked, let them fade away */ return 1; } if (rendcirc && rendcirc->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) { log_fn(LOG_INFO,"pending-join circ %d already here, with intro ack. Stalling. (stream %d sec old)", rendcirc->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_fn(LOG_INFO,"Intro circ %d present and awaiting ack (rend %d). Stalling. (stream %d sec old)", introcirc->n_circ_id, rendcirc ? rendcirc->n_circ_id : 0, conn_age); return 0; } /* now rendcirc and introcirc are each either undefined or not finished */ if (rendcirc && introcirc && rendcirc->purpose == CIRCUIT_PURPOSE_C_REND_READY) { log_fn(LOG_INFO,"ready rend circ %d already here (no intro-ack yet on intro %d). (stream %d sec old)", rendcirc->n_circ_id, introcirc->n_circ_id, conn_age); tor_assert(introcirc->purpose == CIRCUIT_PURPOSE_C_INTRODUCING); if (introcirc->state == CIRCUIT_STATE_OPEN) { log_fn(LOG_INFO,"found open intro circ %d (rend %d); sending introduction. (stream %d sec old)", introcirc->n_circ_id, rendcirc->n_circ_id, conn_age); if (rend_client_send_introduction(introcirc, rendcirc) < 0) { return -1; } rendcirc->timestamp_dirty = time(NULL); introcirc->timestamp_dirty = time(NULL); assert_circuit_ok(rendcirc); assert_circuit_ok(introcirc); return 0; } } log_fn(LOG_INFO,"Intro (%d) and rend (%d) circs are not both ready. Stalling conn. (%d sec old)", introcirc ? introcirc->n_circ_id : 0, rendcirc ? rendcirc->n_circ_id : 0, conn_age); return 0; } }