diff options
Diffstat (limited to 'src/or/circuituse.c')
| -rw-r--r-- | src/or/circuituse.c | 100 |
1 files changed, 77 insertions, 23 deletions
diff --git a/src/or/circuituse.c b/src/or/circuituse.c index 166971c30c..11d78201f4 100644 --- a/src/or/circuituse.c +++ b/src/or/circuituse.c @@ -14,7 +14,7 @@ * 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(). + * 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(), @@ -1876,16 +1876,22 @@ 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) @@ -1893,21 +1899,31 @@ 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)) { log_fn(severity, LD_APP|LD_DIR, @@ -1928,14 +1944,16 @@ 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; @@ -1976,16 +1994,25 @@ 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; @@ -1999,6 +2026,8 @@ 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; @@ -2036,7 +2065,7 @@ 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] == '$') { @@ -2059,7 +2088,7 @@ circuit_get_open_circ_or_launch(entry_connection_t *conn, extend_info = extend_info_new(conn->chosen_exit_name+1, digest, NULL, NULL, &addr, conn->socks_request->port); - } else { + } else { /* ! (want_onehop && conn->chosen_exit_name[0] == '$') */ /* 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, @@ -2077,8 +2106,10 @@ 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) @@ -2087,6 +2118,8 @@ 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)) { @@ -2094,6 +2127,7 @@ 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; @@ -2105,6 +2139,8 @@ 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 @@ -2128,6 +2164,10 @@ 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 @@ -2327,7 +2367,9 @@ 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) @@ -2342,12 +2384,11 @@ 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. */ @@ -2366,6 +2407,7 @@ 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; @@ -2376,12 +2418,14 @@ 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) { @@ -2399,6 +2443,9 @@ 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; @@ -2412,6 +2459,7 @@ 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; @@ -2424,6 +2472,7 @@ 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; @@ -2432,11 +2481,15 @@ 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).", @@ -2445,7 +2498,8 @@ connection_ap_handshake_attach_circuit(entry_connection_t *conn) * 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 */ |