diff options
Diffstat (limited to 'src/or/relay.c')
| -rw-r--r-- | src/or/relay.c | 181 |
1 files changed, 164 insertions, 17 deletions
diff --git a/src/or/relay.c b/src/or/relay.c index 22ce767523..7a074d63da 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -1,30 +1,68 @@ /* Copyright (c) 2001 Matej Pfajfar. * Copyright (c) 2001-2004, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. - * Copyright (c) 2007-2016, The Tor Project, Inc. */ + * Copyright (c) 2007-2017, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** * \file relay.c * \brief Handle relay cell encryption/decryption, plus packaging and * receiving from circuits, plus queuing on circuits. + * + * This is a core modules that makes Tor work. It's responsible for + * dealing with RELAY cells (the ones that travel more than one hop along a + * circuit), by: + * <ul> + * <li>constructing relays cells, + * <li>encrypting relay cells, + * <li>decrypting relay cells, + * <li>demultiplexing relay cells as they arrive on a connection, + * <li>queueing relay cells for retransmission, + * <li>or handling relay cells that are for us to receive (as an exit or a + * client). + * </ul> + * + * RELAY cells are generated throughout the code at the client or relay side, + * using relay_send_command_from_edge() or one of the functions like + * connection_edge_send_command() that calls it. Of particular interest is + * connection_edge_package_raw_inbuf(), which takes information that has + * arrived on an edge connection socket, and packages it as a RELAY_DATA cell + * -- this is how information is actually sent across the Tor network. The + * cryptography for these functions is handled deep in + * circuit_package_relay_cell(), which either adds a single layer of + * encryption (if we're an exit), or multiple layers (if we're the origin of + * the circuit). After construction and encryption, the RELAY cells are + * passed to append_cell_to_circuit_queue(), which queues them for + * transmission and tells the circuitmux (see circuitmux.c) that the circuit + * is waiting to send something. + * + * Incoming RELAY cells arrive at circuit_receive_relay_cell(), called from + * command.c. There they are decrypted and, if they are for us, are passed to + * connection_edge_process_relay_cell(). If they're not for us, they're + * re-queued for retransmission again with append_cell_to_circuit_queue(). + * + * The connection_edge_process_relay_cell() function handles all the different + * types of relay cells, launching requests or transmitting data as needed. **/ #define RELAY_PRIVATE #include "or.h" #include "addressmap.h" +#include "backtrace.h" #include "buffers.h" #include "channel.h" #include "circpathbias.h" #include "circuitbuild.h" #include "circuitlist.h" #include "circuituse.h" +#include "compress.h" #include "config.h" #include "connection.h" #include "connection_edge.h" #include "connection_or.h" #include "control.h" #include "geoip.h" +#include "hs_cache.h" #include "main.h" #include "networkstatus.h" #include "nodelist.h" @@ -38,6 +76,7 @@ #include "routerlist.h" #include "routerparse.h" #include "scheduler.h" +#include "rephist.h" static edge_connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell, cell_direction_t cell_direction, @@ -160,6 +199,82 @@ relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in, return 0; } +/** + * Update channel usage state based on the type of relay cell and + * circuit properties. + * + * This is needed to determine if a client channel is being + * used for application traffic, and if a relay channel is being + * used for multihop circuits and application traffic. The decision + * to pad in channelpadding.c depends upon this info (as well as + * consensus parameters) to decide what channels to pad. + */ +static void +circuit_update_channel_usage(circuit_t *circ, cell_t *cell) +{ + if (CIRCUIT_IS_ORIGIN(circ)) { + /* + * The client state was first set much earlier in + * circuit_send_next_onion_skin(), so we can start padding as early as + * possible. + * + * However, if padding turns out to be expensive, we may want to not do + * it until actual application traffic starts flowing (which is controlled + * via consensus param nf_pad_before_usage). + * + * So: If we're an origin circuit and we've created a full length circuit, + * then any CELL_RELAY cell means application data. Increase the usage + * state of the channel to indicate this. + * + * We want to wait for CELL_RELAY specifically here, so we know that + * the channel was definitely being used for data and not for extends. + * By default, we pad as soon as a channel has been used for *any* + * circuits, so this state is irrelevant to the padding decision in + * the default case. However, if padding turns out to be expensive, + * we would like the ability to avoid padding until we're absolutely + * sure that a channel is used for enough application data to be worth + * padding. + * + * (So it does not matter that CELL_RELAY_EARLY can actually contain + * application data. This is only a load reducing option and that edge + * case does not matter if we're desperately trying to reduce overhead + * anyway. See also consensus parameter nf_pad_before_usage). + */ + if (BUG(!circ->n_chan)) + return; + + if (circ->n_chan->channel_usage == CHANNEL_USED_FOR_FULL_CIRCS && + cell->command == CELL_RELAY) { + circ->n_chan->channel_usage = CHANNEL_USED_FOR_USER_TRAFFIC; + } + } else { + /* If we're a relay circuit, the question is more complicated. Basically: + * we only want to pad connections that carry multihop (anonymous) + * circuits. + * + * We assume we're more than one hop if either the previous hop + * is not a client, or if the previous hop is a client and there's + * a next hop. Then, circuit traffic starts at RELAY_EARLY, and + * user application traffic starts when we see RELAY cells. + */ + or_circuit_t *or_circ = TO_OR_CIRCUIT(circ); + + if (BUG(!or_circ->p_chan)) + return; + + if (!channel_is_client(or_circ->p_chan) || + (channel_is_client(or_circ->p_chan) && circ->n_chan)) { + if (cell->command == CELL_RELAY_EARLY) { + if (or_circ->p_chan->channel_usage < CHANNEL_USED_FOR_FULL_CIRCS) { + or_circ->p_chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + } + } else if (cell->command == CELL_RELAY) { + or_circ->p_chan->channel_usage = CHANNEL_USED_FOR_USER_TRAFFIC; + } + } + } +} + /** Receive a relay cell: * - Crypt it (encrypt if headed toward the origin or if we <b>are</b> the * origin; decrypt if we're headed toward the exit). @@ -189,10 +304,13 @@ circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, return 0; if (relay_crypt(circ, cell, cell_direction, &layer_hint, &recognized) < 0) { - log_warn(LD_BUG,"relay crypt failed. Dropping connection."); + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "relay crypt failed. Dropping connection."); return -END_CIRC_REASON_INTERNAL; } + circuit_update_channel_usage(circ, cell); + if (recognized) { edge_connection_t *conn = NULL; @@ -221,8 +339,13 @@ circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, log_debug(LD_OR,"Sending to origin."); if ((reason = connection_edge_process_relay_cell(cell, circ, conn, layer_hint)) < 0) { - log_warn(LD_OR, - "connection_edge_process_relay_cell (at origin) failed."); + /* If a client is trying to connect to unknown hidden service port, + * END_CIRC_AT_ORIGIN is sent back so we can then close the circuit. + * Do not log warn as this is an expected behavior for a service. */ + if (reason != END_CIRC_AT_ORIGIN) { + log_warn(LD_OR, + "connection_edge_process_relay_cell (at origin) failed."); + } return reason; } } @@ -394,11 +517,13 @@ circuit_package_relay_cell(cell_t *cell, circuit_t *circ, if (!chan) { log_warn(LD_BUG,"outgoing relay cell sent from %s:%d has n_chan==NULL." " Dropping.", filename, lineno); + log_backtrace(LOG_WARN,LD_BUG,""); return 0; /* just drop it */ } if (!CIRCUIT_IS_ORIGIN(circ)) { log_warn(LD_BUG,"outgoing relay cell sent from %s:%d on non-origin " "circ. Dropping.", filename, lineno); + log_backtrace(LOG_WARN,LD_BUG,""); return 0; /* just drop it */ } @@ -564,11 +689,11 @@ relay_command_to_string(uint8_t command) * If you can't send the cell, mark the circuit for close and return -1. Else * return 0. */ -int -relay_send_command_from_edge_(streamid_t stream_id, circuit_t *circ, - uint8_t relay_command, const char *payload, - size_t payload_len, crypt_path_t *cpath_layer, - const char *filename, int lineno) +MOCK_IMPL(int, +relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ, + uint8_t relay_command, const char *payload, + size_t payload_len, crypt_path_t *cpath_layer, + const char *filename, int lineno)) { cell_t cell; relay_header_t rh; @@ -580,14 +705,14 @@ relay_send_command_from_edge_(streamid_t stream_id, circuit_t *circ, memset(&cell, 0, sizeof(cell_t)); cell.command = CELL_RELAY; - if (cpath_layer) { + if (CIRCUIT_IS_ORIGIN(circ)) { + tor_assert(cpath_layer); cell.circ_id = circ->n_circ_id; cell_direction = CELL_DIRECTION_OUT; - } else if (! CIRCUIT_IS_ORIGIN(circ)) { + } else { + tor_assert(! cpath_layer); cell.circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; cell_direction = CELL_DIRECTION_IN; - } else { - return -1; } memset(&rh, 0, sizeof(rh)); @@ -601,6 +726,9 @@ relay_send_command_from_edge_(streamid_t stream_id, circuit_t *circ, log_debug(LD_OR,"delivering %d cell %s.", relay_command, cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward"); + if (relay_command == RELAY_COMMAND_DROP) + rep_hist_padding_count_write(PADDING_TYPE_DROP); + /* If we are sending an END cell and this circuit is used for a tunneled * directory request, advance its state. */ if (relay_command == RELAY_COMMAND_END && circ->dirreq_id) @@ -707,6 +835,16 @@ connection_edge_send_command(edge_connection_t *fromconn, return -1; } +#ifdef MEASUREMENTS_21206 + /* Keep track of the number of RELAY_DATA cells sent for directory + * connections. */ + connection_t *linked_conn = TO_CONN(fromconn)->linked_conn; + + if (linked_conn && linked_conn->type == CONN_TYPE_DIR) { + ++(TO_DIR_CONN(linked_conn)->data_cells_sent); + } +#endif + return relay_send_command_from_edge(fromconn->stream_id, circ, relay_command, payload, payload_len, cpath_layer); @@ -1489,6 +1627,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, switch (rh.command) { case RELAY_COMMAND_DROP: + rep_hist_padding_count_read(PADDING_TYPE_DROP); // log_info(domain,"Got a relay-level padding cell. Dropping."); return 0; case RELAY_COMMAND_BEGIN: @@ -1562,6 +1701,16 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, connection_write_to_buf((char*)(cell->payload + RELAY_HEADER_SIZE), rh.length, TO_CONN(conn)); +#ifdef MEASUREMENTS_21206 + /* Count number of RELAY_DATA cells received on a linked directory + * connection. */ + connection_t *linked_conn = TO_CONN(conn)->linked_conn; + + if (linked_conn && linked_conn->type == CONN_TYPE_DIR) { + ++(TO_DIR_CONN(linked_conn)->data_cells_received); + } +#endif + if (!optimistic_data) { /* Only send a SENDME if we're not getting optimistic data; otherwise * a SENDME could arrive before the CONNECTED. @@ -2472,7 +2621,7 @@ cell_queues_check_size(void) time_t now = time(NULL); size_t alloc = cell_queues_get_total_allocation(); alloc += buf_get_total_allocation(); - alloc += tor_zlib_get_total_allocation(); + alloc += tor_compress_get_total_allocation(); const size_t rend_cache_total = rend_cache_get_total_allocation(); alloc += rend_cache_total; const size_t geoip_client_cache_total = @@ -2487,9 +2636,7 @@ cell_queues_check_size(void) if (rend_cache_total > get_options()->MaxMemInQueues / 5) { const size_t bytes_to_remove = rend_cache_total - (size_t)(get_options()->MaxMemInQueues / 10); - rend_cache_clean_v2_descs_as_dir(now, bytes_to_remove); - alloc -= rend_cache_total; - alloc += rend_cache_get_total_allocation(); + alloc -= hs_cache_handle_oom(time(NULL), bytes_to_remove); } if (geoip_client_cache_total > get_options()->MaxMemInQueues / 5) { const size_t bytes_to_remove = |