diff options
Diffstat (limited to 'src/or/circuituse.c')
| -rw-r--r-- | src/or/circuituse.c | 368 |
1 files changed, 273 insertions, 95 deletions
diff --git a/src/or/circuituse.c b/src/or/circuituse.c index 84574cd5b9..c2b450606b 100644 --- a/src/or/circuituse.c +++ b/src/or/circuituse.c @@ -6,11 +6,30 @@ /** * \file circuituse.c - * \brief Launch the right sort of circuits and attach streams to them. + * \brief Launch the right sort of circuits and attach the right streams to + * them. + * + * As distinct from circuitlist.c, which manages lookups to find circuits, and + * circuitbuild.c, which handles the logistics of circuit construction, this + * module keeps track of which streams can be attached to which circuits (in + * circuit_get_best()), and attaches streams to circuits (with + * circuit_try_attaching_streams(), connection_ap_handshake_attach_circuit(), + * and connection_ap_handshake_attach_chosen_circuit() ). + * + * This module also makes sure that we are building circuits for all of the + * predicted ports, using circuit_remove_handled_ports(), + * circuit_stream_is_being_handled(), and circuit_build_needed_cirs(). It + * handles launching circuits for specific targets using + * circuit_launch_by_extend_info(). + * + * This is also where we handle expiring circuits that have been around for + * too long without actually completing, along with the circuit_build_timeout + * logic in circuitstats.c. **/ #include "or.h" #include "addressmap.h" +#include "bridges.h" #include "channel.h" #include "circpathbias.h" #include "circuitbuild.h" @@ -22,6 +41,7 @@ #include "connection_edge.h" #include "control.h" #include "entrynodes.h" +#include "hs_common.h" #include "nodelist.h" #include "networkstatus.h" #include "policies.h" @@ -154,8 +174,8 @@ circuit_is_acceptable(const origin_circuit_t *origin_circ, 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))) { + rend_cmp_service_ids(rend_data_get_address(edge_conn->rend_data), + rend_data_get_address(origin_circ->rend_data)))) { /* this circ is not for this conn */ return 0; } @@ -530,16 +550,14 @@ circuit_expire_building(void) == 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.", + "(a %s %d-hop circuit in state %s with channel state %s).", TO_ORIGIN_CIRCUIT(victim)->global_identifier, circuit_purpose_to_string(victim->purpose), TO_ORIGIN_CIRCUIT(victim)->build_state ? TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len : -1, circuit_state_to_string(victim->state), - channel_state_to_string(victim->n_chan->state), - num_live_entry_guards(0)); + channel_state_to_string(victim->n_chan->state)); /* We count the timeout here for CBT, because technically this * was a timeout, and the timeout value needs to reset if we @@ -557,7 +575,7 @@ circuit_expire_building(void) "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.", + "anyway.", TO_ORIGIN_CIRCUIT(victim)->global_identifier, circuit_purpose_to_string(victim->purpose), TO_ORIGIN_CIRCUIT(victim)->build_state ? @@ -565,8 +583,7 @@ circuit_expire_building(void) -1, circuit_state_to_string(victim->state), channel_state_to_string(victim->n_chan->state), - (long)build_close_ms, - num_live_entry_guards(0)); + (long)build_close_ms); } } @@ -780,6 +797,25 @@ circuit_expire_building(void) } SMARTLIST_FOREACH_END(victim); } +/** + * Mark for close all circuits that start here, that were built through a + * guard we weren't sure if we wanted to use, and that have been waiting + * around for way too long. + */ +void +circuit_expire_waiting_for_better_guard(void) +{ + SMARTLIST_FOREACH_BEGIN(circuit_get_global_origin_circuit_list(), + origin_circuit_t *, circ) { + if (TO_CIRCUIT(circ)->marked_for_close) + continue; + if (circ->guard_state == NULL) + continue; + if (entry_guard_state_should_expire(circ->guard_state)) + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_NONE); + } SMARTLIST_FOREACH_END(circ); +} + /** For debugging #8387: track when we last called * circuit_expire_old_circuits_clientside. */ static time_t last_expired_clientside_circuits = 0; @@ -1003,8 +1039,117 @@ circuit_stream_is_being_handled(entry_connection_t *conn, /** 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. +/* Return true if a circuit is available for use, meaning that it is open, + * clean, usable for new multi-hop connections, and a general purpose origin + * circuit. + * Accept any kind of circuit, return false if the above conditions are not + * met. */ +STATIC int +circuit_is_available_for_use(const circuit_t *circ) +{ + const origin_circuit_t *origin_circ; + cpath_build_state_t *build_state; + + if (!CIRCUIT_IS_ORIGIN(circ)) + return 0; /* We first filter out only origin circuits before doing the + following checks. */ + if (circ->marked_for_close) + return 0; /* Don't mess with marked circs */ + if (circ->timestamp_dirty) + return 0; /* Only count clean circs */ + if (circ->purpose != CIRCUIT_PURPOSE_C_GENERAL) + return 0; /* We only pay attention to general purpose circuits. + General purpose circuits are always origin circuits. */ + + origin_circ = CONST_TO_ORIGIN_CIRCUIT(circ); + if (origin_circ->unusable_for_new_conns) + return 0; + + build_state = origin_circ->build_state; + if (build_state->onehop_tunnel) + return 0; + + return 1; +} + +/* Return true if we need any more exit circuits. + * needs_uptime and needs_capacity are set only if we need 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. */ +STATIC int +needs_exit_circuits(time_t now, int *needs_uptime, int *needs_capacity) +{ + return (!circuit_all_predicted_ports_handled(now, needs_uptime, + needs_capacity) && + router_have_consensus_path() == CONSENSUS_PATH_EXIT); +} + +/* Hidden services need at least this many internal circuits */ +#define SUFFICIENT_UPTIME_INTERNAL_HS_SERVERS 3 + +/* Return true if we need any more hidden service server circuits. + * HS servers only need an internal circuit. */ +STATIC int +needs_hs_server_circuits(int num_uptime_internal) +{ + return (num_rend_services() && + num_uptime_internal < SUFFICIENT_UPTIME_INTERNAL_HS_SERVERS && + router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN); +} + +/* We need at least this many internal circuits for hidden service clients */ +#define SUFFICIENT_INTERNAL_HS_CLIENTS 3 + +/* We need at least this much uptime for internal circuits for hidden service + * clients */ +#define SUFFICIENT_UPTIME_INTERNAL_HS_CLIENTS 2 + +/* Return true if we need any more hidden service client circuits. + * HS clients only need an internal circuit. */ +STATIC int +needs_hs_client_circuits(time_t now, int *needs_uptime, int *needs_capacity, + int num_internal, int num_uptime_internal) +{ + int used_internal_recently = rep_hist_get_predicted_internal(now, + needs_uptime, + needs_capacity); + int requires_uptime = num_uptime_internal < + SUFFICIENT_UPTIME_INTERNAL_HS_CLIENTS && + needs_uptime; + + return (used_internal_recently && + (requires_uptime || num_internal < SUFFICIENT_INTERNAL_HS_CLIENTS) && + router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN); +} + +/* The minimum number of open slots we should keep in order to preemptively + * build circuits. */ +#define CBT_MIN_REMAINING_PREEMPTIVE_CIRCUITS 2 + +/* Check to see if we need more circuits to have a good build timeout. However, + * leave a couple slots open so that we can still build circuits preemptively + * as needed. */ +#define CBT_MAX_UNUSED_OPEN_CIRCUITS (MAX_UNUSED_OPEN_CIRCUITS - \ + CBT_MIN_REMAINING_PREEMPTIVE_CIRCUITS) + +/* Return true if we need more circuits for a good build timeout. + * XXXX make the assumption that build timeout streams should be + * created whenever we can build internal circuits. */ +STATIC int +needs_circuits_for_build(int num) +{ + if (router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN) { + if (num < CBT_MAX_UNUSED_OPEN_CIRCUITS && + !circuit_build_times_disabled(get_options()) && + circuit_build_times_needs_circuits_now(get_circuit_build_times())) { + return 1; + } + } + return 0; +} + +/** Determine 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 @@ -1016,25 +1161,14 @@ circuit_predict_and_launch_new(void) time_t now = time(NULL); int flags = 0; - /* First, count how many of each type of circuit we have already. */ + /* Count how many of each type of circuit we currently have. */ SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) { - 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) + if (!circuit_is_available_for_use(circ)) continue; + num++; + + cpath_build_state_t *build_state = TO_ORIGIN_CIRCUIT(circ)->build_state; if (build_state->is_internal) num_internal++; if (build_state->need_uptime && build_state->is_internal) @@ -1044,19 +1178,14 @@ circuit_predict_and_launch_new(void) /* 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. - * Exits (obviously) require an exit circuit. */ - if (!circuit_all_predicted_ports_handled(now, &port_needs_uptime, - &port_needs_capacity) - && router_have_consensus_path() == CONSENSUS_PATH_EXIT) { + return; + + if (needs_exit_circuits(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); @@ -1064,12 +1193,10 @@ circuit_predict_and_launch_new(void) return; } - /* Third, see if we need any more hidden service (server) circuits. - * HS servers only need an internal circuit. */ - if (num_rend_services() && num_uptime_internal < 3 - && router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN) { + if (needs_hs_server_circuits(num_uptime_internal)) { 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.", @@ -1078,18 +1205,16 @@ circuit_predict_and_launch_new(void) return; } - /* Fourth, see if we need any more hidden service (client) circuits. - * HS clients only need an internal circuit. */ - if (rep_hist_get_predicted_internal(now, &hidserv_needs_uptime, - &hidserv_needs_capacity) && - ((num_uptime_internal<2 && hidserv_needs_uptime) || - num_internal<3) - && router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN) { + if (needs_hs_client_circuits(now, &hidserv_needs_uptime, + &hidserv_needs_capacity, + num_internal, num_uptime_internal)) + { 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.", @@ -1098,26 +1223,17 @@ circuit_predict_and_launch_new(void) 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. - * XXXX make the assumption that build timeout streams should be - * created whenever we can build internal circuits. */ - if (router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN) { - 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; - /* if there are no exits in the consensus, make timeout - * circuits internal */ - if (router_have_consensus_path() == CONSENSUS_PATH_INTERNAL) - flags |= CIRCLAUNCH_IS_INTERNAL; + if (needs_circuits_for_build(num)) { + flags = CIRCLAUNCH_NEED_CAPACITY; + /* if there are no exits in the consensus, make timeout + * circuits internal */ + if (router_have_consensus_path() == CONSENSUS_PATH_INTERNAL) + flags |= CIRCLAUNCH_IS_INTERNAL; + log_info(LD_CIRC, "Have %d clean circs need another buildtime test circ.", num); circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags); return; - } } } @@ -1284,7 +1400,7 @@ circuit_expire_old_circuits_clientside(void) cutoff = now; last_expired_clientside_circuits = now.tv_sec; - if (! circuit_build_times_disabled() && + if (! circuit_build_times_disabled(get_options()) && 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 */ @@ -1613,7 +1729,9 @@ circuit_build_failed(origin_circuit_t *circ) "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)); + /* New guard API: we failed. */ + if (circ->guard_state) + entry_guard_failed(&circ->guard_state); /* 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); @@ -1874,16 +1992,22 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, c->state, conn_state_to_string(c->type, c->state)); } tor_assert(ENTRY_TO_CONN(conn)->state == AP_CONN_STATE_CIRCUIT_WAIT); + + /* Will the exit policy of the exit node apply to this stream? */ check_exit_policy = conn->socks_request->command == SOCKS_COMMAND_CONNECT && !conn->use_begindir && !connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn)); + + /* Does this connection want a one-hop circuit? */ want_onehop = conn->want_onehop; + /* Do we need a high-uptime circuit? */ need_uptime = !conn->want_onehop && !conn->use_begindir && smartlist_contains_int_as_string(options->LongLivedPorts, conn->socks_request->port); + /* Do we need an "internal" circuit? */ if (desired_circuit_purpose != CIRCUIT_PURPOSE_C_GENERAL) need_internal = 1; else if (conn->use_begindir || conn->want_onehop) @@ -1891,23 +2015,33 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, else need_internal = 0; - circ = circuit_get_best(conn, 1, desired_circuit_purpose, + /* We now know what kind of circuit we need. See if there is an + * open circuit that we can use for this stream */ + circ = circuit_get_best(conn, 1 /* Insist on open circuits */, + desired_circuit_purpose, need_uptime, need_internal); if (circ) { + /* We got a circuit that will work for this stream! We can return it. */ *circp = circ; return 1; /* we're happy */ } + /* Okay, there's no circuit open that will work for this stream. Let's + * see if there's an in-progress circuit or if we have to launch one */ + + /* Do we know enough directory info to build circuits at all? */ int have_path = have_enough_path_info(!need_internal); if (!want_onehop && (!router_have_minimum_dir_info() || !have_path)) { + /* If we don't have enough directory information, we can't build + * multihop circuits. + */ 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. */ + /* Retry some stuff that might help the connection work. */ if (entry_list_is_constrained(options) && - entries_known_but_down(options)) { + guards_retry_optimistic(options)) { log_fn(severity, LD_APP|LD_DIR, "Application request when we haven't %s. " "Optimistically trying known %s again.", @@ -1915,7 +2049,6 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, "used client functionality lately" : "received a consensus with exits", 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 %s. " @@ -1926,14 +2059,16 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, 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() + /* Since we didn't have enough directory info, we can't attach now. 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? */ + /* Check whether the exit policy of the chosen exit, or the exit policies + * of _all_ nodes, would forbid this node. */ if (check_exit_policy) { if (!conn->chosen_exit_name) { struct in_addr in; @@ -1974,16 +2109,25 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, } } - /* is one already on the way? */ - circ = circuit_get_best(conn, 0, desired_circuit_purpose, + /* Now, check whether there already a circuit on the way that could handle + * this stream. This check matches the one above, but this time we + * do not require that the circuit will work. */ + circ = circuit_get_best(conn, 0 /* don't insist on open circuits */, + desired_circuit_purpose, need_uptime, need_internal); if (circ) log_debug(LD_CIRC, "one on the way!"); + if (!circ) { + /* No open or in-progress circuit could handle this stream! We + * will have to launch one! + */ + + /* The chosen exit node, if there is one. */ extend_info_t *extend_info=NULL; - uint8_t new_circ_purpose; const int n_pending = count_pending_general_client_circuits(); + /* Do we have too many pending circuits? */ if (n_pending >= options->MaxClientCircuitsPending) { static ratelim_t delay_limit = RATELIM_INIT(10*60); char *m; @@ -1997,6 +2141,8 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, return 0; } + /* If this is a hidden service trying to start an introduction point, + * handle that case. */ 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; @@ -2005,7 +2151,7 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, if (!extend_info) { log_info(LD_REND, "No intro points for '%s': re-fetching service descriptor.", - safe_str_client(rend_data->onion_address)); + safe_str_client(rend_data_get_address(rend_data))); rend_client_refetch_v2_renddesc(rend_data); connection_ap_mark_as_non_pending_circuit(conn); ENTRY_TO_CONN(conn)->state = AP_CONN_STATE_RENDDESC_WAIT; @@ -2013,7 +2159,7 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, } log_info(LD_REND,"Chose %s as intro point for '%s'.", extend_info_describe(extend_info), - safe_str_client(rend_data->onion_address)); + safe_str_client(rend_data_get_address(rend_data))); } /* If we have specified a particular exit node for our @@ -2034,12 +2180,16 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, "Discarding this circuit.", conn->chosen_exit_name); return -1; } - } else { + } else { /* ! (r && node_has_descriptor(r)) */ log_debug(LD_DIR, "considering %d, %s", want_onehop, conn->chosen_exit_name); if (want_onehop && conn->chosen_exit_name[0] == '$') { /* We're asking for a one-hop circuit to a router that * we don't have a routerinfo about. Make up an extend_info. */ + /* XXX prop220: we need to make chosen_exit_name able to + * encode both key formats. This is not absolutely critical + * since this is just for one-hop circuits, but we should + * still get it done */ char digest[DIGEST_LEN]; char *hexdigest = conn->chosen_exit_name+1; tor_addr_t addr; @@ -2054,10 +2204,13 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, escaped_safe_str_client(conn->socks_request->address)); return -1; } + /* XXXX prop220 add a workaround for ed25519 ID below*/ extend_info = extend_info_new(conn->chosen_exit_name+1, - digest, NULL, NULL, &addr, - conn->socks_request->port); - } else { + digest, + NULL, /* Ed25519 ID */ + NULL, NULL, /* onion keys */ + &addr, conn->socks_request->port); + } else { /* ! (want_onehop && conn->chosen_exit_name[0] == '$') */ /* 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, @@ -2075,8 +2228,10 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, } } } - } + } /* Done checking for general circutis with chosen exits. */ + /* What purpose do we need to launch this circuit with? */ + uint8_t new_circ_purpose; 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) @@ -2085,6 +2240,8 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, new_circ_purpose = desired_circuit_purpose; #ifdef ENABLE_TOR2WEB_MODE + /* If tor2Web is on, then hidden service requests should be one-hop. + */ if (options->Tor2webMode && (new_circ_purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND || new_circ_purpose == CIRCUIT_PURPOSE_C_INTRODUCING)) { @@ -2092,6 +2249,7 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, } #endif + /* Determine what kind of a circuit to launch, and actually launch it. */ { int flags = CIRCLAUNCH_NEED_CAPACITY; if (want_onehop) flags |= CIRCLAUNCH_ONEHOP_TUNNEL; @@ -2103,6 +2261,8 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, extend_info_free(extend_info); + /* Now trigger things that need to happen when we launch circuits */ + 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 @@ -2126,6 +2286,10 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, } } } /* endif (!circ) */ + + /* We either found a good circuit, or launched a new circuit, or failed to + * do so. Report success, and delay. */ + if (circ) { /* Mark the circuit with the isolation fields for this connection. * When the circuit arrives, we'll clear these flags: this is @@ -2325,7 +2489,9 @@ connection_ap_handshake_attach_chosen_circuit(entry_connection_t *conn, pathbias_count_use_attempt(circ); + /* Now, actually link the connection. */ link_apconn_to_circ(conn, circ, cpath); + tor_assert(conn->socks_request); if (conn->socks_request->command == SOCKS_COMMAND_CONNECT) { if (!conn->use_begindir) @@ -2340,12 +2506,11 @@ connection_ap_handshake_attach_chosen_circuit(entry_connection_t *conn, 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. +/** Try to find a safe live circuit for stream <b>conn</b>. If we find one, + * attach the stream, send appropriate cells, and return 1. Otherwise, + * try to launch new circuit(s) for the stream. If we can launch + * circuits, return 0. Otherwise, if we simply can't proceed with + * this stream, return -1. (conn needs to die, and is maybe already marked). */ /* XXXX this function should mark for close whenever it returns -1; * its callers shouldn't have to worry about that. */ @@ -2364,6 +2529,7 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) conn_age = (int)(time(NULL) - base_conn->timestamp_created); + /* Is this connection so old that we should give up on it? */ if (conn_age >= get_options()->SocksTimeout) { int severity = (tor_addr_is_null(&base_conn->addr) && !base_conn->port) ? LOG_INFO : LOG_NOTICE; @@ -2374,12 +2540,14 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) return -1; } + /* We handle "general" (non-onion) connections much more straightforwardly. + */ if (!connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn))) { /* we're a general conn */ origin_circuit_t *circ=NULL; /* Are we linked to a dir conn that aims to fetch a consensus? - * We check here because this conn might no longer be needed. */ + * We check here because the conn might no longer be needed. */ if (base_conn->linked_conn && base_conn->linked_conn->type == CONN_TYPE_DIR && base_conn->linked_conn->purpose == DIR_PURPOSE_FETCH_CONSENSUS) { @@ -2397,6 +2565,9 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) } } + /* If we have a chosen exit, we need to use a circuit that's + * open to that exit. See what exit we meant, and whether we can use it. + */ if (conn->chosen_exit_name) { const node_t *node = node_get_by_nickname(conn->chosen_exit_name, 1); int opt = conn->chosen_exit_optional; @@ -2410,6 +2581,7 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) "Requested exit point '%s' is not known. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { + /* If we are allowed to ignore the .exit request, do so */ conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); return 0; @@ -2422,6 +2594,7 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) "would refuse request. %s.", conn->chosen_exit_name, opt ? "Trying others" : "Closing"); if (opt) { + /* If we are allowed to ignore the .exit request, do so */ conn->chosen_exit_optional = 0; tor_free(conn->chosen_exit_name); return 0; @@ -2430,20 +2603,25 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) } } - /* find the circuit that we should use, if there is one. */ + /* Find the circuit that we should use, if there is one. Otherwise + * launch it. */ retval = circuit_get_open_circ_or_launch( conn, CIRCUIT_PURPOSE_C_GENERAL, &circ); - if (retval < 1) // XXXX++ if we totally fail, this still returns 0 -RD + if (retval < 1) { + /* We were either told "-1" (complete failure) or 0 (circuit in + * progress); we can't attach this stream yet. */ 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 + /* print the circ's path, so clients 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. */ + /* We have found a suitable circuit for our conn. Hurray. Do + * the attachment. */ return connection_ap_handshake_attach_chosen_circuit(conn, circ, NULL); } else { /* we're a rendezvous conn */ |