diff --git a/changes/ticket22804 b/changes/ticket22804 new file mode 100644 index 0000000000..a5d71c5120 --- /dev/null +++ b/changes/ticket22804 @@ -0,0 +1,4 @@ + o Code simplification and refactoring: + + - Split the enormous circuit_send_next_onion_skin() function into + multiple subfunctions. Closes ticket 22804. diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index 833c0b98b7..8bb7c94d74 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -74,6 +74,10 @@ static int onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit); static crypt_path_t *onion_next_hop_in_cpath(crypt_path_t *cpath); static int onion_extend_cpath(origin_circuit_t *circ); static int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice); +static int circuit_send_first_onion_skin(origin_circuit_t *circ); +static int circuit_build_no_more_hops(origin_circuit_t *circ); +static int circuit_send_intermediate_onion_skin(origin_circuit_t *circ, + crypt_path_t *hop); /** This function tries to get a channel to the specified endpoint, * and then calls command_setup_channel() to give it the right @@ -912,234 +916,275 @@ circuit_purpose_may_omit_guard(int purpose) * If circ's first hop is closed, then we need to build a create * cell and send it forward. * - * Otherwise, we need to build a relay extend cell and send it - * forward. + * Otherwise, if circ's cpath still has any non-open hops, we need to + * build a relay extend cell and send it forward to the next non-open hop. + * + * If all hops on the cpath are open, we're done building the circuit + * and we should do housekeeping for the newly opened circuit. * * Return -reason if we want to tear down circ, else return 0. */ int circuit_send_next_onion_skin(origin_circuit_t *circ) { - crypt_path_t *hop; - const node_t *node; - tor_assert(circ); if (circ->cpath->state == CPATH_STATE_CLOSED) { - /* This is the first hop. */ - create_cell_t cc; - int fast; - int len; - log_debug(LD_CIRC,"First skin; sending create cell."); - memset(&cc, 0, sizeof(cc)); - if (circ->build_state->onehop_tunnel) - control_event_bootstrap(BOOTSTRAP_STATUS_ONEHOP_CREATE, 0); - else { - control_event_bootstrap(BOOTSTRAP_STATUS_CIRCUIT_CREATE, 0); - - /* If this is not a one-hop tunnel, the channel is being used - * for traffic that wants anonymity and protection from traffic - * analysis (such as netflow record retention). That means we want - * to pad it. - */ - if (circ->base_.n_chan->channel_usage < CHANNEL_USED_FOR_FULL_CIRCS) - circ->base_.n_chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; - } - - node = node_get_by_id(circ->base_.n_chan->identity_digest); - fast = should_use_create_fast_for_circuit(circ); - if (!fast) { - /* We are an OR and we know the right onion key: we should - * send a create cell. - */ - circuit_pick_create_handshake(&cc.cell_type, &cc.handshake_type, - circ->cpath->extend_info); - } else { - /* We are not an OR, and we're building the first hop of a circuit to a - * new OR: we can be speedy and use CREATE_FAST to save an RSA operation - * and a DH operation. */ - cc.cell_type = CELL_CREATE_FAST; - cc.handshake_type = ONION_HANDSHAKE_TYPE_FAST; - } - - len = onion_skin_create(cc.handshake_type, - circ->cpath->extend_info, - &circ->cpath->handshake_state, - cc.onionskin); - if (len < 0) { - log_warn(LD_CIRC,"onion_skin_create (first hop) failed."); - return - END_CIRC_REASON_INTERNAL; - } - cc.handshake_len = len; - - if (circuit_deliver_create_cell(TO_CIRCUIT(circ), &cc, 0) < 0) - return - END_CIRC_REASON_RESOURCELIMIT; - - circ->cpath->state = CPATH_STATE_AWAITING_KEYS; - circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_BUILDING); - log_info(LD_CIRC,"First hop: finished sending %s cell to '%s'", - fast ? "CREATE_FAST" : "CREATE", - node ? node_describe(node) : ""); - } else { - extend_cell_t ec; - int len; - tor_assert(circ->cpath->state == CPATH_STATE_OPEN); - tor_assert(circ->base_.state == CIRCUIT_STATE_BUILDING); - log_debug(LD_CIRC,"starting to send subsequent skin."); - hop = onion_next_hop_in_cpath(circ->cpath); - memset(&ec, 0, sizeof(ec)); - if (!hop) { - /* done building the circuit. whew. */ - guard_usable_t r; - if (! circ->guard_state) { - if (circuit_get_cpath_len(circ) != 1 && - ! circuit_purpose_may_omit_guard(circ->base_.purpose) && - get_options()->UseEntryGuards) { - log_warn(LD_BUG, "%d-hop circuit %p with purpose %d has no " - "guard state", - circuit_get_cpath_len(circ), circ, circ->base_.purpose); - } - r = GUARD_USABLE_NOW; - } else { - r = entry_guard_succeeded(&circ->guard_state); - } - const int is_usable_for_streams = (r == GUARD_USABLE_NOW); - if (r == GUARD_USABLE_NOW) { - circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN); - } else if (r == GUARD_MAYBE_USABLE_LATER) { - // Wait till either a better guard succeeds, or till - // all better guards fail. - circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_GUARD_WAIT); - } else { - tor_assert_nonfatal(r == GUARD_USABLE_NEVER); - return - END_CIRC_REASON_INTERNAL; - } - - /* XXXX #21422 -- the rest of this branch needs careful thought! - * Some of the things here need to happen when a circuit becomes - * mechanically open; some need to happen when it is actually usable. - * I think I got them right, but more checking would be wise. -NM - */ - - if (circuit_timeout_want_to_count_circ(circ)) { - struct timeval end; - long timediff; - tor_gettimeofday(&end); - timediff = tv_mdiff(&circ->base_.timestamp_began, &end); - - /* - * 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 (timediff < 0 || - timediff > 2*get_circuit_build_close_time_ms()+1000) { - log_notice(LD_CIRC, "Strange value for circuit build time: %ldmsec. " - "Assuming clock jump. Purpose %d (%s)", timediff, - circ->base_.purpose, - circuit_purpose_to_string(circ->base_.purpose)); - } else if (!circuit_build_times_disabled(get_options())) { - /* Only count circuit times if the network is live */ - if (circuit_build_times_network_check_live( - get_circuit_build_times())) { - circuit_build_times_add_time(get_circuit_build_times_mutable(), - (build_time_t)timediff); - circuit_build_times_set_timeout(get_circuit_build_times_mutable()); - } - - if (circ->base_.purpose != CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) { - circuit_build_times_network_circ_success( - get_circuit_build_times_mutable()); - } - } - } - log_info(LD_CIRC,"circuit built!"); - circuit_reset_failure_count(0); - - if (circ->build_state->onehop_tunnel || circ->has_opened) { - control_event_bootstrap(BOOTSTRAP_STATUS_REQUESTING_STATUS, 0); - } - - pathbias_count_build_success(circ); - circuit_rep_hist_note_result(circ); - if (is_usable_for_streams) - circuit_has_opened(circ); /* do other actions as necessary */ - - if (!have_completed_a_circuit() && !circ->build_state->onehop_tunnel) { - const or_options_t *options = get_options(); - note_that_we_completed_a_circuit(); - /* FFFF Log a count of known routers here */ - log_notice(LD_GENERAL, - "Tor has successfully opened a circuit. " - "Looks like client functionality is working."); - if (control_event_bootstrap(BOOTSTRAP_STATUS_DONE, 0) == 0) { - log_notice(LD_GENERAL, - "Tor has successfully opened a circuit. " - "Looks like client functionality is working."); - } - control_event_client_status(LOG_NOTICE, "CIRCUIT_ESTABLISHED"); - clear_broken_connection_map(1); - if (server_mode(options) && !check_whether_orport_reachable(options)) { - inform_testing_reachability(); - consider_testing_reachability(1, 1); - } - } - - /* We're done with measurement circuits here. Just close them */ - if (circ->base_.purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) { - circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED); - } - return 0; - } - - if (tor_addr_family(&hop->extend_info->addr) != AF_INET) { - log_warn(LD_BUG, "Trying to extend to a non-IPv4 address."); - return - END_CIRC_REASON_INTERNAL; - } - - circuit_pick_extend_handshake(&ec.cell_type, - &ec.create_cell.cell_type, - &ec.create_cell.handshake_type, - hop->extend_info); - - tor_addr_copy(&ec.orport_ipv4.addr, &hop->extend_info->addr); - ec.orport_ipv4.port = hop->extend_info->port; - tor_addr_make_unspec(&ec.orport_ipv6.addr); - memcpy(ec.node_id, hop->extend_info->identity_digest, DIGEST_LEN); - /* Set the ED25519 identity too -- it will only get included - * in the extend2 cell if we're configured to use it, though. */ - ed25519_pubkey_copy(&ec.ed_pubkey, &hop->extend_info->ed_identity); - - len = onion_skin_create(ec.create_cell.handshake_type, - hop->extend_info, - &hop->handshake_state, - ec.create_cell.onionskin); - if (len < 0) { - log_warn(LD_CIRC,"onion_skin_create failed."); - return - END_CIRC_REASON_INTERNAL; - } - ec.create_cell.handshake_len = len; - - log_info(LD_CIRC,"Sending extend relay cell."); - { - uint8_t command = 0; - uint16_t payload_len=0; - uint8_t payload[RELAY_PAYLOAD_SIZE]; - if (extend_cell_format(&command, &payload_len, payload, &ec)<0) { - log_warn(LD_CIRC,"Couldn't format extend cell"); - return -END_CIRC_REASON_INTERNAL; - } - - /* send it to hop->prev, because it will transfer - * it to a create cell and then send to hop */ - if (relay_send_command_from_edge(0, TO_CIRCUIT(circ), - command, - (char*)payload, payload_len, - hop->prev) < 0) - return 0; /* circuit is closed */ - } - hop->state = CPATH_STATE_AWAITING_KEYS; + /* Case one: we're on the first hop. */ + return circuit_send_first_onion_skin(circ); } + + tor_assert(circ->cpath->state == CPATH_STATE_OPEN); + tor_assert(circ->base_.state == CIRCUIT_STATE_BUILDING); + crypt_path_t *hop = onion_next_hop_in_cpath(circ->cpath); + + if (hop) { + /* Case two: we're on a hop after the first. */ + return circuit_send_intermediate_onion_skin(circ, hop); + } + + /* Case three: the circuit is finished. Do housekeeping tasks on it. */ + return circuit_build_no_more_hops(circ); +} + +/** + * Called from circuit_send_next_onion_skin() when we find ourselves connected + * to the first hop in circ: Send a CREATE or CREATE2 or CREATE_FAST + * cell to that hop. Return 0 on success; -reason on failure (if the circuit + * should be torn down). + */ +static int +circuit_send_first_onion_skin(origin_circuit_t *circ) +{ + int fast; + int len; + const node_t *node; + create_cell_t cc; + memset(&cc, 0, sizeof(cc)); + + log_debug(LD_CIRC,"First skin; sending create cell."); + + if (circ->build_state->onehop_tunnel) { + control_event_bootstrap(BOOTSTRAP_STATUS_ONEHOP_CREATE, 0); + } else { + control_event_bootstrap(BOOTSTRAP_STATUS_CIRCUIT_CREATE, 0); + + /* If this is not a one-hop tunnel, the channel is being used + * for traffic that wants anonymity and protection from traffic + * analysis (such as netflow record retention). That means we want + * to pad it. + */ + if (circ->base_.n_chan->channel_usage < CHANNEL_USED_FOR_FULL_CIRCS) + circ->base_.n_chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + } + + node = node_get_by_id(circ->base_.n_chan->identity_digest); + fast = should_use_create_fast_for_circuit(circ); + if (!fast) { + /* We know the right onion key: we should send a create cell. */ + circuit_pick_create_handshake(&cc.cell_type, &cc.handshake_type, + circ->cpath->extend_info); + } else { + /* We don't know an onion key, so we need to fall back to CREATE_FAST. */ + cc.cell_type = CELL_CREATE_FAST; + cc.handshake_type = ONION_HANDSHAKE_TYPE_FAST; + } + + len = onion_skin_create(cc.handshake_type, + circ->cpath->extend_info, + &circ->cpath->handshake_state, + cc.onionskin); + if (len < 0) { + log_warn(LD_CIRC,"onion_skin_create (first hop) failed."); + return - END_CIRC_REASON_INTERNAL; + } + cc.handshake_len = len; + + if (circuit_deliver_create_cell(TO_CIRCUIT(circ), &cc, 0) < 0) + return - END_CIRC_REASON_RESOURCELIMIT; + + circ->cpath->state = CPATH_STATE_AWAITING_KEYS; + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_BUILDING); + log_info(LD_CIRC,"First hop: finished sending %s cell to '%s'", + fast ? "CREATE_FAST" : "CREATE", + node ? node_describe(node) : ""); + return 0; +} + +/** + * Called from circuit_send_next_onion_skin() when we find that we have no + * more hops: mark the circuit as finished, and perform the necessary + * bookkeeping. Return 0 on success; -reason on failure (if the circuit + * should be torn down). + */ +static int +circuit_build_no_more_hops(origin_circuit_t *circ) +{ + guard_usable_t r; + if (! circ->guard_state) { + if (circuit_get_cpath_len(circ) != 1 && + ! circuit_purpose_may_omit_guard(circ->base_.purpose) && + get_options()->UseEntryGuards) { + log_warn(LD_BUG, "%d-hop circuit %p with purpose %d has no " + "guard state", + circuit_get_cpath_len(circ), circ, circ->base_.purpose); + } + r = GUARD_USABLE_NOW; + } else { + r = entry_guard_succeeded(&circ->guard_state); + } + const int is_usable_for_streams = (r == GUARD_USABLE_NOW); + if (r == GUARD_USABLE_NOW) { + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN); + } else if (r == GUARD_MAYBE_USABLE_LATER) { + // Wait till either a better guard succeeds, or till + // all better guards fail. + circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_GUARD_WAIT); + } else { + tor_assert_nonfatal(r == GUARD_USABLE_NEVER); + return - END_CIRC_REASON_INTERNAL; + } + + /* XXXX #21422 -- the rest of this branch needs careful thought! + * Some of the things here need to happen when a circuit becomes + * mechanically open; some need to happen when it is actually usable. + * I think I got them right, but more checking would be wise. -NM + */ + + if (circuit_timeout_want_to_count_circ(circ)) { + struct timeval end; + long timediff; + tor_gettimeofday(&end); + timediff = tv_mdiff(&circ->base_.timestamp_began, &end); + + /* + * 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 (timediff < 0 || + timediff > 2*get_circuit_build_close_time_ms()+1000) { + log_notice(LD_CIRC, "Strange value for circuit build time: %ldmsec. " + "Assuming clock jump. Purpose %d (%s)", timediff, + circ->base_.purpose, + circuit_purpose_to_string(circ->base_.purpose)); + } else if (!circuit_build_times_disabled(get_options())) { + /* Only count circuit times if the network is live */ + if (circuit_build_times_network_check_live( + get_circuit_build_times())) { + circuit_build_times_add_time(get_circuit_build_times_mutable(), + (build_time_t)timediff); + circuit_build_times_set_timeout(get_circuit_build_times_mutable()); + } + + if (circ->base_.purpose != CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) { + circuit_build_times_network_circ_success( + get_circuit_build_times_mutable()); + } + } + } + log_info(LD_CIRC,"circuit built!"); + circuit_reset_failure_count(0); + + if (circ->build_state->onehop_tunnel || circ->has_opened) { + control_event_bootstrap(BOOTSTRAP_STATUS_REQUESTING_STATUS, 0); + } + + pathbias_count_build_success(circ); + circuit_rep_hist_note_result(circ); + if (is_usable_for_streams) + circuit_has_opened(circ); /* do other actions as necessary */ + + if (!have_completed_a_circuit() && !circ->build_state->onehop_tunnel) { + const or_options_t *options = get_options(); + note_that_we_completed_a_circuit(); + /* FFFF Log a count of known routers here */ + log_notice(LD_GENERAL, + "Tor has successfully opened a circuit. " + "Looks like client functionality is working."); + if (control_event_bootstrap(BOOTSTRAP_STATUS_DONE, 0) == 0) { + log_notice(LD_GENERAL, + "Tor has successfully opened a circuit. " + "Looks like client functionality is working."); + } + control_event_client_status(LOG_NOTICE, "CIRCUIT_ESTABLISHED"); + clear_broken_connection_map(1); + if (server_mode(options) && !check_whether_orport_reachable(options)) { + inform_testing_reachability(); + consider_testing_reachability(1, 1); + } + } + + /* We're done with measurement circuits here. Just close them */ + if (circ->base_.purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) { + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED); + } + return 0; +} + +/** + * Called from circuit_send_next_onion_skin() when we find that we have a hop + * other than the first that we need to extend to: use hop's + * information to extend the circuit another step. Return 0 on success; + * -reason on failure (if the circuit should be torn down). + */ +static int +circuit_send_intermediate_onion_skin(origin_circuit_t *circ, + crypt_path_t *hop) +{ + int len; + extend_cell_t ec; + memset(&ec, 0, sizeof(ec)); + + log_debug(LD_CIRC,"starting to send subsequent skin."); + + if (tor_addr_family(&hop->extend_info->addr) != AF_INET) { + log_warn(LD_BUG, "Trying to extend to a non-IPv4 address."); + return - END_CIRC_REASON_INTERNAL; + } + + circuit_pick_extend_handshake(&ec.cell_type, + &ec.create_cell.cell_type, + &ec.create_cell.handshake_type, + hop->extend_info); + + tor_addr_copy(&ec.orport_ipv4.addr, &hop->extend_info->addr); + ec.orport_ipv4.port = hop->extend_info->port; + tor_addr_make_unspec(&ec.orport_ipv6.addr); + memcpy(ec.node_id, hop->extend_info->identity_digest, DIGEST_LEN); + /* Set the ED25519 identity too -- it will only get included + * in the extend2 cell if we're configured to use it, though. */ + ed25519_pubkey_copy(&ec.ed_pubkey, &hop->extend_info->ed_identity); + + len = onion_skin_create(ec.create_cell.handshake_type, + hop->extend_info, + &hop->handshake_state, + ec.create_cell.onionskin); + if (len < 0) { + log_warn(LD_CIRC,"onion_skin_create failed."); + return - END_CIRC_REASON_INTERNAL; + } + ec.create_cell.handshake_len = len; + + log_info(LD_CIRC,"Sending extend relay cell."); + { + uint8_t command = 0; + uint16_t payload_len=0; + uint8_t payload[RELAY_PAYLOAD_SIZE]; + if (extend_cell_format(&command, &payload_len, payload, &ec)<0) { + log_warn(LD_CIRC,"Couldn't format extend cell"); + return -END_CIRC_REASON_INTERNAL; + } + + /* send it to hop->prev, because that relay will transfer + * it to a create cell and then send to hop */ + if (relay_send_command_from_edge(0, TO_CIRCUIT(circ), + command, + (char*)payload, payload_len, + hop->prev) < 0) + return 0; /* circuit is closed */ + } + hop->state = CPATH_STATE_AWAITING_KEYS; return 0; }