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- /* Copyright 2001 Matej Pfajfar.
- * Copyright 2001-2004 Roger Dingledine.
- * Copyright 2004-2005 Roger Dingledine, Nick Mathewson. */
- /* See LICENSE for licensing information */
- /* $Id$ */
- const char command_c_id[] = "$Id$";
- /**
- * \file command.c
- * \brief Functions for processing incoming cells.
- **/
- /* In-points to command.c:
- *
- * - command_process_cell(), called from
- * connection_or_process_cells_from_inbuf() in connection_or.c
- */
- #include "or.h"
- /** Keep statistics about how many of each type of cell we've received. */
- unsigned long stats_n_padding_cells_processed = 0;
- unsigned long stats_n_create_cells_processed = 0;
- unsigned long stats_n_created_cells_processed = 0;
- unsigned long stats_n_relay_cells_processed = 0;
- unsigned long stats_n_destroy_cells_processed = 0;
- /* These are the main four functions for processing cells */
- static void command_process_create_cell(cell_t *cell, connection_t *conn);
- static void command_process_created_cell(cell_t *cell, connection_t *conn);
- static void command_process_relay_cell(cell_t *cell, connection_t *conn);
- static void command_process_destroy_cell(cell_t *cell, connection_t *conn);
- #ifdef KEEP_TIMING_STATS
- /** This is a wrapper function around the actual function that processes the
- * <b>cell</b> that just arrived on <b>conn</b>. Increment <b>*time</b>
- * by the number of microseconds used by the call to <b>*func(cell, conn)</b>.
- */
- static void
- command_time_process_cell(cell_t *cell, connection_t *conn, int *time,
- void (*func)(cell_t *, connection_t *))
- {
- struct timeval start, end;
- long time_passed;
- tor_gettimeofday(&start);
- (*func)(cell, conn);
- tor_gettimeofday(&end);
- time_passed = tv_udiff(&start, &end) ;
- if (time_passed > 10000) { /* more than 10ms */
- debug(LD_OR,"That call just took %ld ms.",time_passed/1000);
- }
- if (time_passed < 0) {
- info(LD_GENERAL,"That call took us back in time!");
- time_passed = 0;
- }
- *time += time_passed;
- }
- #endif
- /** Process a <b>cell</b> that was just received on <b>conn</b>. Keep internal
- * statistics about how many of each cell we've processed so far
- * this second, and the total number of microseconds it took to
- * process each type of cell.
- */
- void
- command_process_cell(cell_t *cell, connection_t *conn)
- {
- #ifdef KEEP_TIMING_STATS
- /* how many of each cell have we seen so far this second? needs better
- * name. */
- static int num_create=0, num_created=0, num_relay=0, num_destroy=0;
- /* how long has it taken to process each type of cell? */
- static int create_time=0, created_time=0, relay_time=0, destroy_time=0;
- static time_t current_second = 0; /* from previous calls to time */
- time_t now = time(NULL);
- if (now > current_second) { /* the second has rolled over */
- /* print stats */
- info(LD_OR,"At end of second: %d creates (%d ms), %d createds (%d ms), %d relays (%d ms), %d destroys (%d ms)",
- num_create, create_time/1000,
- num_created, created_time/1000,
- num_relay, relay_time/1000,
- num_destroy, destroy_time/1000);
- /* zero out stats */
- num_create = num_created = num_relay = num_destroy = 0;
- create_time = created_time = relay_time = destroy_time = 0;
- /* remember which second it is, for next time */
- current_second = now;
- }
- #endif
- switch (cell->command) {
- case CELL_PADDING:
- ++stats_n_padding_cells_processed;
- /* do nothing */
- break;
- case CELL_CREATE:
- case CELL_CREATE_FAST:
- ++stats_n_create_cells_processed;
- #ifdef KEEP_TIMING_STATS
- ++num_create;
- command_time_process_cell(cell, conn, &create_time,
- command_process_create_cell);
- #else
- command_process_create_cell(cell, conn);
- #endif
- break;
- case CELL_CREATED:
- case CELL_CREATED_FAST:
- ++stats_n_created_cells_processed;
- #ifdef KEEP_TIMING_STATS
- ++num_created;
- command_time_process_cell(cell, conn, &created_time,
- command_process_created_cell);
- #else
- command_process_created_cell(cell, conn);
- #endif
- break;
- case CELL_RELAY:
- ++stats_n_relay_cells_processed;
- #ifdef KEEP_TIMING_STATS
- ++num_relay;
- command_time_process_cell(cell, conn, &relay_time,
- command_process_relay_cell);
- #else
- command_process_relay_cell(cell, conn);
- #endif
- break;
- case CELL_DESTROY:
- ++stats_n_destroy_cells_processed;
- #ifdef KEEP_TIMING_STATS
- ++num_destroy;
- command_time_process_cell(cell, conn, &destroy_time,
- command_process_destroy_cell);
- #else
- command_process_destroy_cell(cell, conn);
- #endif
- break;
- default:
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Cell of unknown type (%d) received. Dropping.", cell->command);
- break;
- }
- }
- /** Process a 'create' <b>cell</b> that just arrived from <b>conn</b>. Make a new circuit
- * with the p_circ_id specified in cell. Put the circuit in state
- * onionskin_pending, and pass the onionskin to the cpuworker. Circ will
- * get picked up again when the cpuworker finishes decrypting it.
- */
- static void
- command_process_create_cell(cell_t *cell, connection_t *conn)
- {
- circuit_t *circ;
- if (we_are_hibernating()) {
- info(LD_OR,"Received create cell but we're shutting down. Sending back destroy.");
- connection_send_destroy(cell->circ_id, conn);
- return;
- }
- /* If the high bit of the circuit ID is not as expected, then switch
- * which half of the space we'll use for our own CREATE cells.
- *
- * This can happen because Tor 0.0.9pre5 and earlier decide which
- * half to use based on nickname, and we now use identity keys.
- */
- if ((cell->circ_id & (1<<15)) && conn->circ_id_type == CIRC_ID_TYPE_HIGHER) {
- info(LD_OR, "Got a high circuit ID from %s (%d); switching to low circuit IDs.",
- conn->nickname ? conn->nickname : "client", conn->s);
- conn->circ_id_type = CIRC_ID_TYPE_LOWER;
- } else if (!(cell->circ_id & (1<<15)) && conn->circ_id_type == CIRC_ID_TYPE_LOWER) {
- info(LD_OR, "Got a low circuit ID from %s (%d); switching to high circuit IDs.",
- conn->nickname ? conn->nickname : "client", conn->s);
- conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
- }
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (circ) {
- routerinfo_t *router = router_get_by_digest(conn->identity_digest);
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "received CREATE cell (circID %d) for known circ. Dropping (age %d).",
- cell->circ_id, (int)(time(NULL) - conn->timestamp_created));
- if (router)
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Details: nickname '%s', platform '%s'.",
- router->nickname, router->platform);
- return;
- }
- circ = circuit_new(cell->circ_id, conn);
- circ->purpose = CIRCUIT_PURPOSE_OR;
- circ->state = CIRCUIT_STATE_ONIONSKIN_PENDING;
- if (cell->command == CELL_CREATE) {
- circ->onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
- memcpy(circ->onionskin, cell->payload, ONIONSKIN_CHALLENGE_LEN);
- /* hand it off to the cpuworkers, and then return */
- if (assign_to_cpuworker(NULL, CPUWORKER_TASK_ONION, circ) < 0) {
- warn(LD_GENERAL,"Failed to hand off onionskin. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- debug(LD_OR,"success: handed off onionskin.");
- } else {
- char keys[CPATH_KEY_MATERIAL_LEN];
- char reply[DIGEST_LEN*2];
- tor_assert(cell->command == CELL_CREATE_FAST);
- if (fast_server_handshake(cell->payload, reply, keys, sizeof(keys))<0) {
- warn(LD_OR,"Failed to generate key material. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- if (onionskin_answer(circ, CELL_CREATED_FAST, reply, keys)<0) {
- warn(LD_OR,"Failed to reply to CREATE_FAST cell. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- }
- }
- /** Process a 'created' <b>cell</b> that just arrived from <b>conn</b>. Find the circuit
- * that it's intended for. If we're not the origin of the circuit, package
- * the 'created' cell in an 'extended' relay cell and pass it back. If we
- * are the origin of the circuit, send it to circuit_finish_handshake() to
- * finish processing keys, and then call circuit_send_next_onion_skin() to
- * extend to the next hop in the circuit if necessary.
- */
- static void
- command_process_created_cell(cell_t *cell, connection_t *conn)
- {
- circuit_t *circ;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (!circ) {
- info(LD_OR,"(circID %d) unknown circ (probably got a destroy earlier). Dropping.", cell->circ_id);
- return;
- }
- if (circ->n_circ_id != cell->circ_id) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,
- "got created cell from OPward? Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- if (CIRCUIT_IS_ORIGIN(circ)) { /* we're the OP. Handshake this. */
- debug(LD_OR,"at OP. Finishing handshake.");
- if (circuit_finish_handshake(circ, cell->command, cell->payload) < 0) {
- warn(LD_OR,"circuit_finish_handshake failed.");
- circuit_mark_for_close(circ);
- return;
- }
- debug(LD_OR,"Moving to next skin.");
- if (circuit_send_next_onion_skin(circ) < 0) {
- info(LD_OR,"circuit_send_next_onion_skin failed.");
- circuit_mark_for_close(circ); /* XXX push this circuit_close lower */
- return;
- }
- } else { /* pack it into an extended relay cell, and send it. */
- debug(LD_OR,"Converting created cell to extended relay cell, sending.");
- connection_edge_send_command(NULL, circ, RELAY_COMMAND_EXTENDED,
- cell->payload, ONIONSKIN_REPLY_LEN, NULL);
- }
- }
- /** Process a 'relay' <b>cell</b> that just arrived from <b>conn</b>. Make sure
- * it came in with a recognized circ_id. Pass it on to
- * circuit_receive_relay_cell() for actual processing.
- */
- static void
- command_process_relay_cell(cell_t *cell, connection_t *conn)
- {
- circuit_t *circ;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (!circ) {
- debug(LD_OR,"unknown circuit %d on connection from %s:%d. Dropping.",
- cell->circ_id, conn->address, conn->port);
- return;
- }
- if (circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit in create_wait. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- if (cell->circ_id == circ->p_circ_id) { /* it's an outgoing cell */
- if (circuit_receive_relay_cell(cell, circ, CELL_DIRECTION_OUT) < 0) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit_receive_relay_cell (forward) failed. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- } else { /* it's an ingoing cell */
- if (circuit_receive_relay_cell(cell, circ, CELL_DIRECTION_IN) < 0) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit_receive_relay_cell (backward) failed. Closing.");
- circuit_mark_for_close(circ);
- return;
- }
- }
- }
- /** Process a 'destroy' <b>cell</b> that just arrived from
- * <b>conn</b>. Find the circ that it refers to (if any).
- *
- * If the circ is in state
- * onionskin_pending, then call onion_pending_remove() to remove it
- * from the pending onion list (note that if it's already being
- * processed by the cpuworker, it won't be in the list anymore; but
- * when the cpuworker returns it, the circuit will be gone, and the
- * cpuworker response will be dropped).
- *
- * Then mark the circuit for close (which marks all edges for close,
- * and passes the destroy cell onward if necessary).
- */
- static void
- command_process_destroy_cell(cell_t *cell, connection_t *conn)
- {
- circuit_t *circ;
- circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
- if (!circ) {
- info(LD_OR,"unknown circuit %d on connection from %s:%d. Dropping.",
- cell->circ_id, conn->address, conn->port);
- return;
- }
- debug(LD_OR,"Received for circID %d.",cell->circ_id);
- if (circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) {
- onion_pending_remove(circ);
- }
- if (cell->circ_id == circ->p_circ_id) {
- /* the destroy came from behind */
- circuit_set_circid_orconn(circ, 0, NULL, P_CONN_CHANGED);
- circuit_mark_for_close(circ);
- } else { /* the destroy came from ahead */
- circuit_set_circid_orconn(circ, 0, NULL, N_CONN_CHANGED);
- if (CIRCUIT_IS_ORIGIN(circ)) {
- circuit_mark_for_close(circ);
- } else {
- debug(LD_OR, "Delivering 'truncated' back.");
- connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED,
- NULL, 0, NULL);
- }
- }
- }
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