/* Copyright 2001,2002,2003 Roger Dingledine, Matej Pfajfar. */ /* See LICENSE for licensing information */ /* $Id$ */ #include "or.h" extern or_options_t options; /* command-line and config-file options */ static int relay_crypt(circuit_t *circ, cell_t *cell, char cell_direction, crypt_path_t **layer_hint, char *recognized); static connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell, int cell_direction); static void circuit_free_cpath_node(crypt_path_t *victim); static uint16_t get_unique_circ_id_by_conn(connection_t *conn, int circ_id_type); unsigned long stats_n_relay_cells_relayed = 0; unsigned long stats_n_relay_cells_delivered = 0; /********* START VARIABLES **********/ static circuit_t *global_circuitlist=NULL; char *circuit_state_to_string[] = { "doing handshakes", /* 0 */ "processing the onion", /* 1 */ "connecting to firsthop", /* 2 */ "open" /* 3 */ }; /********* END VARIABLES ************/ void circuit_add(circuit_t *circ) { if(!global_circuitlist) { /* first one */ global_circuitlist = circ; circ->next = NULL; } else { circ->next = global_circuitlist; global_circuitlist = circ; } } void circuit_remove(circuit_t *circ) { circuit_t *tmpcirc; assert(circ && global_circuitlist); if(global_circuitlist == circ) { global_circuitlist = global_circuitlist->next; return; } for(tmpcirc = global_circuitlist;tmpcirc->next;tmpcirc = tmpcirc->next) { if(tmpcirc->next == circ) { tmpcirc->next = circ->next; return; } } } circuit_t *circuit_new(uint16_t p_circ_id, connection_t *p_conn) { circuit_t *circ; circ = tor_malloc_zero(sizeof(circuit_t)); circ->timestamp_created = time(NULL); circ->p_circ_id = p_circ_id; circ->p_conn = p_conn; circ->state = CIRCUIT_STATE_ONIONSKIN_PENDING; /* CircIDs */ circ->p_circ_id = p_circ_id; /* circ->n_circ_id remains 0 because we haven't identified the next hop yet */ circ->package_window = CIRCWINDOW_START; circ->deliver_window = CIRCWINDOW_START; circ->next_stream_id = crypto_pseudo_rand_int(1<<16); circuit_add(circ); return circ; } void circuit_free(circuit_t *circ) { assert(circ); if (circ->n_crypto) crypto_free_cipher_env(circ->n_crypto); if (circ->p_crypto) crypto_free_cipher_env(circ->p_crypto); if (circ->n_digest) crypto_free_digest_env(circ->n_digest); if (circ->p_digest) crypto_free_digest_env(circ->p_digest); if(circ->build_state) tor_free(circ->build_state->chosen_exit); tor_free(circ->build_state); circuit_free_cpath(circ->cpath); free(circ); } void circuit_free_cpath(crypt_path_t *cpath) { crypt_path_t *victim, *head=cpath; if(!cpath) return; /* it's a doubly linked list, so we have to notice when we've * gone through it once. */ while(cpath->next && cpath->next != head) { victim = cpath; cpath = victim->next; circuit_free_cpath_node(victim); } circuit_free_cpath_node(cpath); } static void circuit_free_cpath_node(crypt_path_t *victim) { if(victim->f_crypto) crypto_free_cipher_env(victim->f_crypto); if(victim->b_crypto) crypto_free_cipher_env(victim->b_crypto); if(victim->f_digest) crypto_free_digest_env(victim->f_digest); if(victim->b_digest) crypto_free_digest_env(victim->b_digest); if(victim->handshake_state) crypto_dh_free(victim->handshake_state); free(victim); } /* return 0 if can't get a unique circ_id. */ static uint16_t get_unique_circ_id_by_conn(connection_t *conn, int circ_id_type) { uint16_t test_circ_id; int attempts=0; uint16_t high_bit; assert(conn && conn->type == CONN_TYPE_OR); high_bit = (circ_id_type == CIRC_ID_TYPE_HIGHER) ? 1<<15 : 0; do { /* Sequentially iterate over test_circ_id=1...1<<15-1 until we find a * circID such that (high_bit|test_circ_id) is not already used. */ test_circ_id = conn->next_circ_id++; if (test_circ_id == 0 || test_circ_id >= 1<<15) { test_circ_id = 1; conn->next_circ_id = 2; } if(++attempts > 1<<15) { /* Make sure we don't loop forever if all circ_id's are used. This * matters because it's an external DoS vulnerability. */ log_fn(LOG_WARN,"No unused circ IDs. Failing."); return 0; } test_circ_id |= high_bit; } while(circuit_get_by_circ_id_conn(test_circ_id, conn)); return test_circ_id; } circuit_t *circuit_get_by_circ_id_conn(uint16_t circ_id, connection_t *conn) { circuit_t *circ; connection_t *tmpconn; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->p_circ_id == circ_id) { if(circ->p_conn == conn) return circ; for(tmpconn = circ->p_streams; tmpconn; tmpconn = tmpconn->next_stream) { if(tmpconn == conn) return circ; } } if(circ->n_circ_id == circ_id) { if(circ->n_conn == conn) return circ; for(tmpconn = circ->n_streams; tmpconn; tmpconn = tmpconn->next_stream) { if(tmpconn == conn) return circ; } } } return NULL; } circuit_t *circuit_get_by_conn(connection_t *conn) { circuit_t *circ; connection_t *tmpconn; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->p_conn == conn) return circ; if(circ->n_conn == conn) return circ; for(tmpconn = circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream) if(tmpconn == conn) return circ; for(tmpconn = circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream) if(tmpconn == conn) return circ; } return NULL; } /* Find the newest circ that conn can use, preferably one which is * dirty. Circ must not be too old. * If !conn, return newest. * * If must_be_open, ignore circs not in CIRCUIT_STATE_OPEN. */ circuit_t *circuit_get_newest(connection_t *conn, int must_be_open) { circuit_t *circ, *newest=NULL, *leastdirty=NULL; routerinfo_t *exitrouter; for(circ=global_circuitlist;circ;circ = circ->next) { if(!circ->cpath) continue; /* this circ doesn't start at us */ if(must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn)) continue; /* ignore non-open circs */ if(conn) { if(circ->state == CIRCUIT_STATE_OPEN && circ->n_conn) /* open */ exitrouter = router_get_by_addr_port(circ->cpath->prev->addr, circ->cpath->prev->port); else /* not open */ exitrouter = router_get_by_nickname(circ->build_state->chosen_exit); if(!exitrouter || connection_ap_can_use_exit(conn, exitrouter) == ADDR_POLICY_REJECTED) { /* can't exit from this router */ continue; } } if(!newest || newest->timestamp_created < circ->timestamp_created) { newest = circ; } if(conn && circ->timestamp_dirty && (!leastdirty || leastdirty->timestamp_dirty < circ->timestamp_dirty)) { leastdirty = circ; } } if(leastdirty && leastdirty->timestamp_dirty+options.NewCircuitPeriod > time(NULL)) { /* log_fn(LOG_DEBUG,"Choosing in-use circuit %s:%d:%d.", leastdirty->n_conn->address, leastdirty->n_port, leastdirty->n_circ_id); */ return leastdirty; } if(newest) { /* log_fn(LOG_DEBUG,"Choosing circuit %s:%d:%d.", newest->n_conn->address, newest->n_port, newest->n_circ_id); */ return newest; } return NULL; } #define MIN_SECONDS_BEFORE_EXPIRING_CIRC 10 /* circuits that were born at the end of their second might be expired * after 10.1 seconds; circuits born at the beginning might be expired * after closer to 11 seconds. */ /* close all circuits that start at us, aren't open, and were born * at least MIN_SECONDS_BEFORE_EXPIRING_CIRC seconds ago */ void circuit_expire_building(void) { int now = time(NULL); circuit_t *victim, *circ = global_circuitlist; while(circ) { victim = circ; circ = circ->next; if(victim->cpath && victim->state != CIRCUIT_STATE_OPEN && victim->timestamp_created + MIN_SECONDS_BEFORE_EXPIRING_CIRC+1 < now) { if(victim->n_conn) log_fn(LOG_INFO,"Abandoning circ %s:%d:%d (state %d:%s)", victim->n_conn->address, victim->n_port, victim->n_circ_id, victim->state, circuit_state_to_string[victim->state]); else log_fn(LOG_INFO,"Abandoning circ %d (state %d:%s)", victim->n_circ_id, victim->state, circuit_state_to_string[victim->state]); circuit_log_path(LOG_INFO,victim); circuit_close(victim); } } } /* count the number of circs starting at us that aren't open */ int circuit_count_building(void) { circuit_t *circ; int num=0; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->cpath && circ->state != CIRCUIT_STATE_OPEN) num++; } return num; } #define MIN_CIRCUITS_HANDLING_STREAM 2 /* return 1 if at least MIN_CIRCUITS_HANDLING_STREAM non-open circuits * will have an acceptable exit node for conn. Else return 0. */ int circuit_stream_is_being_handled(connection_t *conn) { circuit_t *circ; routerinfo_t *exitrouter; int num=0; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->cpath && circ->state != CIRCUIT_STATE_OPEN) { exitrouter = router_get_by_nickname(circ->build_state->chosen_exit); if(exitrouter && connection_ap_can_use_exit(conn, exitrouter) != ADDR_POLICY_REJECTED) if(++num >= MIN_CIRCUITS_HANDLING_STREAM) return 1; } } return 0; } /* update digest from the payload of cell. assign integrity part to cell. */ static void relay_set_digest(crypto_digest_env_t *digest, cell_t *cell) { char integrity[4]; relay_header_t rh; crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE); crypto_digest_get_digest(digest, integrity, 4); log_fn(LOG_DEBUG,"Putting digest of %u %u %u %u into relay cell.", integrity[0], integrity[1], integrity[2], integrity[3]); relay_header_unpack(&rh, cell->payload); memcpy(rh.integrity, integrity, 4); relay_header_pack(cell->payload, &rh); } /* update digest from the payload of cell (with the integrity part set * to 0). If the integrity part is valid return 1, else restore digest * and cell to their original state and return 0. */ static int relay_digest_matches(crypto_digest_env_t *digest, cell_t *cell) { char received_integrity[4], calculated_integrity[4]; relay_header_t rh; crypto_digest_env_t *backup_digest=NULL; backup_digest = crypto_digest_dup(digest); relay_header_unpack(&rh, cell->payload); memcpy(received_integrity, rh.integrity, 4); memset(rh.integrity, 0, 4); relay_header_pack(cell->payload, &rh); log_fn(LOG_DEBUG,"Reading digest of %u %u %u %u from relay cell.", received_integrity[0], received_integrity[1], received_integrity[2], received_integrity[3]); crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE); crypto_digest_get_digest(digest, calculated_integrity, 4); if(memcmp(received_integrity, calculated_integrity, 4)) { log_fn(LOG_INFO,"Recognized=0 but bad digest. Not recognizing."); // (%d vs %d).", received_integrity, calculated_integrity); /* restore digest to its old form */ crypto_digest_assign(digest, backup_digest); /* restore the relay header */ memcpy(rh.integrity, received_integrity, 4); relay_header_pack(cell->payload, &rh); crypto_free_digest_env(backup_digest); return 0; } crypto_free_digest_env(backup_digest); return 1; } static int relay_crypt_one_payload(crypto_cipher_env_t *cipher, char *in, int encrypt_mode) { char out[CELL_PAYLOAD_SIZE]; /* 'in' must be this size too */ relay_header_t rh; relay_header_unpack(&rh, in); log_fn(LOG_DEBUG,"before crypt: %d",rh.recognized); if(( encrypt_mode && crypto_cipher_encrypt(cipher, in, CELL_PAYLOAD_SIZE, out)) || (!encrypt_mode && crypto_cipher_decrypt(cipher, in, CELL_PAYLOAD_SIZE, out))) { log_fn(LOG_WARN,"Error during crypt: %s", crypto_perror()); return -1; } memcpy(in,out,CELL_PAYLOAD_SIZE); relay_header_unpack(&rh, in); log_fn(LOG_DEBUG,"after crypt: %d",rh.recognized); return 0; } /* receive a relay cell: - crypt it (encrypt APward, decrypt at AP, decrypt exitward) - check if recognized (if exitward) - if recognized, check digest, find right conn, deliver to edge. - else connection_or_write_cell_to_buf to the right conn */ int circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction) { connection_t *conn=NULL; crypt_path_t *layer_hint=NULL; char recognized=0; assert(cell && circ); assert(cell_direction == CELL_DIRECTION_OUT || cell_direction == CELL_DIRECTION_IN); if(relay_crypt(circ, cell, cell_direction, &layer_hint, &recognized) < 0) { log_fn(LOG_WARN,"relay crypt failed. Dropping connection."); return -1; } if(recognized) { conn = relay_lookup_conn(circ, cell, cell_direction); if(cell_direction == CELL_DIRECTION_OUT) { ++stats_n_relay_cells_delivered; log_fn(LOG_DEBUG,"Sending to exit."); if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_EXIT, NULL) < 0) { log_fn(LOG_WARN,"connection_edge_process_relay_cell (at exit) failed."); return -1; } } if(cell_direction == CELL_DIRECTION_IN) { ++stats_n_relay_cells_delivered; log_fn(LOG_DEBUG,"Sending to AP."); if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_AP, layer_hint) < 0) { log_fn(LOG_WARN,"connection_edge_process_relay_cell (at AP) failed."); return -1; } } return 0; } /* not recognized. pass it on. */ if(cell_direction == CELL_DIRECTION_OUT) { cell->circ_id = circ->n_circ_id; /* switch it */ conn = circ->n_conn; } else { cell->circ_id = circ->p_circ_id; /* switch it */ conn = circ->p_conn; } if(!conn) { log_fn(LOG_WARN,"Didn't recognize cell, but circ stops here! Dropping."); return 0; /* XXX if this warning never triggers, then return -1 */ } log_fn(LOG_DEBUG,"Passing on unrecognized cell."); ++stats_n_relay_cells_relayed; connection_or_write_cell_to_buf(cell, conn); return 0; } /* wrap this into receive_relay_cell one day */ static int relay_crypt(circuit_t *circ, cell_t *cell, char cell_direction, crypt_path_t **layer_hint, char *recognized) { crypt_path_t *thishop; relay_header_t rh; assert(circ && cell && recognized); assert(cell_direction == CELL_DIRECTION_IN || cell_direction == CELL_DIRECTION_OUT); if(cell_direction == CELL_DIRECTION_IN) { if(circ->cpath) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */ thishop = circ->cpath; if(thishop->state != CPATH_STATE_OPEN) { log_fn(LOG_WARN,"Relay cell before first created cell?"); return -1; } do { /* Remember: cpath is in forward order, that is, first hop first. */ assert(thishop); if(relay_crypt_one_payload(thishop->b_crypto, cell->payload, 0) < 0) return -1; relay_header_unpack(&rh, cell->payload); if(rh.recognized == 0) { /* it's possibly recognized. have to check digest to be sure. */ if(relay_digest_matches(thishop->b_digest, cell)) { *recognized = 1; *layer_hint = thishop; return 0; } } thishop = thishop->next; } while(thishop != circ->cpath && thishop->state == CPATH_STATE_OPEN); log_fn(LOG_WARN,"in-cell at OP not recognized. Dropping."); return 0; } else { /* we're in the middle. Just one crypt. */ if(relay_crypt_one_payload(circ->p_crypto, cell->payload, 1) < 0) return -1; log_fn(LOG_DEBUG,"Skipping recognized check, because we're not the OP."); } } else /* cell_direction == CELL_DIRECTION_OUT */ { /* we're in the middle. Just one crypt. */ if(relay_crypt_one_payload(circ->n_crypto, cell->payload, 0) < 0) return -1; relay_header_unpack(&rh, cell->payload); if (rh.recognized == 0) { /* it's possibly recognized. have to check digest to be sure. */ if(relay_digest_matches(circ->n_digest, cell)) { *recognized = 1; return 0; } } } return 0; } /* package a relay cell: - if from AP: encrypt it to the right conn if 'recognized' doesn't conflict, else insert dummies first as appropriate - if from exit: encrypt it - connection_or_write_cell_to_buf to the right conn */ int circuit_package_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction, crypt_path_t *layer_hint) { connection_t *conn; /* where to send the cell */ crypt_path_t *thishop; /* counter for repeated crypts */ if(cell_direction == CELL_DIRECTION_OUT) { conn = circ->n_conn; if(!conn) { log_fn(LOG_INFO,"outgoing relay cell has n_conn==NULL. Dropping."); return 0; /* just drop it */ } relay_set_digest(layer_hint->f_digest, cell); thishop = layer_hint; /* moving from farthest to nearest hop */ do { assert(thishop); log_fn(LOG_DEBUG,"crypting a layer of the relay cell."); if(relay_crypt_one_payload(thishop->f_crypto, cell->payload, 1) < 0) { return -1; } thishop = thishop->prev; } while (thishop != circ->cpath->prev); } else { /* incoming cell */ conn = circ->p_conn; if(!conn) { log_fn(LOG_INFO,"incoming relay cell has p_conn==NULL. Dropping."); return 0; /* just drop it */ } relay_set_digest(circ->p_digest, cell); if(relay_crypt_one_payload(circ->p_crypto, cell->payload, 1) < 0) return -1; } ++stats_n_relay_cells_relayed; connection_or_write_cell_to_buf(cell, conn); return 0; } static connection_t * relay_lookup_conn(circuit_t *circ, cell_t *cell, int cell_direction) { connection_t *tmpconn; relay_header_t rh; relay_header_unpack(&rh, cell->payload); if(!rh.stream_id) return NULL; if(cell_direction == CELL_DIRECTION_OUT) tmpconn = circ->n_streams; else tmpconn = circ->p_streams; for( ; tmpconn; tmpconn=tmpconn->next_stream) { if(rh.stream_id == tmpconn->stream_id) { log_fn(LOG_DEBUG,"found conn for stream %d.", rh.stream_id); return tmpconn; } log_fn(LOG_DEBUG,"considered stream %d, not it.",tmpconn->stream_id); } return NULL; /* probably a begin relay cell */ } void circuit_resume_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) { connection_t *conn; assert(edge_type == EDGE_EXIT || edge_type == EDGE_AP); log_fn(LOG_DEBUG,"resuming"); if(edge_type == EDGE_EXIT) conn = circ->n_streams; else conn = circ->p_streams; for( ; conn; conn=conn->next_stream) { if((edge_type == EDGE_EXIT && conn->package_window > 0) || (edge_type == EDGE_AP && conn->package_window > 0 && conn->cpath_layer == layer_hint)) { connection_start_reading(conn); connection_edge_package_raw_inbuf(conn); /* handle whatever might still be on the inbuf */ /* If the circuit won't accept any more data, return without looking * at any more of the streams. Any connections that should be stopped * have already been stopped by connection_edge_package_raw_inbuf. */ if(circuit_consider_stop_edge_reading(circ, edge_type, layer_hint)) return; } } } /* returns 1 if the window is empty, else 0. If it's empty, tell edge conns to stop reading. */ int circuit_consider_stop_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) { connection_t *conn = NULL; assert(edge_type == EDGE_EXIT || edge_type == EDGE_AP); assert(edge_type == EDGE_EXIT || layer_hint); log_fn(LOG_DEBUG,"considering"); if(edge_type == EDGE_EXIT && circ->package_window <= 0) conn = circ->n_streams; else if(edge_type == EDGE_AP && layer_hint->package_window <= 0) conn = circ->p_streams; else return 0; for( ; conn; conn=conn->next_stream) if(!layer_hint || conn->cpath_layer == layer_hint) connection_stop_reading(conn); log_fn(LOG_DEBUG,"yes. stopped."); return 1; } void circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) { while((edge_type == EDGE_AP ? layer_hint->deliver_window : circ->deliver_window) < CIRCWINDOW_START - CIRCWINDOW_INCREMENT) { log_fn(LOG_DEBUG,"Queueing circuit sendme."); if(edge_type == EDGE_AP) layer_hint->deliver_window += CIRCWINDOW_INCREMENT; else circ->deliver_window += CIRCWINDOW_INCREMENT; if(connection_edge_send_command(NULL, circ, RELAY_COMMAND_SENDME, NULL, 0, layer_hint) < 0) { log_fn(LOG_WARN,"connection_edge_send_command failed. Returning."); return; /* the circuit's closed, don't continue */ } } } void circuit_close(circuit_t *circ) { connection_t *conn; assert(circ); circuit_remove(circ); if(circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) { onion_pending_remove(circ); } if(circ->n_conn) connection_send_destroy(circ->n_circ_id, circ->n_conn); for(conn=circ->n_streams; conn; conn=conn->next_stream) { connection_send_destroy(circ->n_circ_id, conn); } if(circ->p_conn) connection_send_destroy(circ->n_circ_id, circ->p_conn); for(conn=circ->p_streams; conn; conn=conn->next_stream) { connection_send_destroy(circ->p_circ_id, conn); } if (circ->state == CIRCUIT_STATE_BUILDING || circ->state == CIRCUIT_STATE_OR_WAIT) { /* If we never built the circuit, note it as a failure. */ /* Note that we can't just check circ->cpath here, because if * circuit-building failed immediately, it won't be set yet. */ circuit_increment_failure_count(); } circuit_free(circ); } void circuit_detach_stream(circuit_t *circ, connection_t *conn) { connection_t *prevconn; assert(circ); assert(conn); if(conn == circ->p_streams) { circ->p_streams = conn->next_stream; return; } if(conn == circ->n_streams) { circ->n_streams = conn->next_stream; return; } for(prevconn = circ->p_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ; if(prevconn && prevconn->next_stream) { prevconn->next_stream = conn->next_stream; return; } for(prevconn = circ->n_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ; if(prevconn && prevconn->next_stream) { prevconn->next_stream = conn->next_stream; return; } log_fn(LOG_ERR,"edge conn not in circuit's list?"); assert(0); /* should never get here */ } void circuit_about_to_close_connection(connection_t *conn) { /* send destroys for all circuits using conn */ /* currently, we assume it's too late to flush conn's buf here. * down the road, maybe we'll consider that eof doesn't mean can't-write */ circuit_t *circ; switch(conn->type) { case CONN_TYPE_OR: /* We must close all the circuits on it. */ while((circ = circuit_get_by_conn(conn))) { if(circ->n_conn == conn) /* it's closing in front of us */ circ->n_conn = NULL; if(circ->p_conn == conn) /* it's closing behind us */ circ->p_conn = NULL; circuit_close(circ); } return; case CONN_TYPE_AP: case CONN_TYPE_EXIT: /* It's an edge conn. Need to remove it from the linked list of * conn's for this circuit. Confirm that 'end' relay command has * been sent. But don't kill the circuit. */ circ = circuit_get_by_conn(conn); if(!circ) return; if(!conn->has_sent_end) { log_fn(LOG_INFO,"Edge connection hasn't sent end yet? Bug."); if(connection_edge_end(conn, END_STREAM_REASON_MISC, conn->cpath_layer) < 0) log_fn(LOG_WARN,"1: I called connection_edge_end redundantly."); } circuit_detach_stream(circ, conn); } /* end switch */ } void circuit_log_path(int severity, circuit_t *circ) { static char b[1024]; struct crypt_path_t *hop; char *states[] = {"closed", "waiting for keys", "open"}; routerinfo_t *router; assert(circ->cpath); sprintf(b,"circ (length %d, exit %s): ", circ->build_state->desired_path_len, circ->build_state->chosen_exit); hop=circ->cpath; do { router = router_get_by_addr_port(hop->addr,hop->port); if(router) { /* XXX strcat allows buffer overflow */ strcat(b,router->nickname); strcat(b,"("); strcat(b,states[hop->state]); strcat(b,"),"); } else { strcat(b,"UNKNOWN,"); } hop=hop->next; } while(hop!=circ->cpath); log_fn(severity,"%s",b); } static void circuit_dump_details(int severity, circuit_t *circ, int poll_index, char *type, int this_circid, int other_circid) { struct crypt_path_t *hop; log(severity,"Conn %d has %s circuit: circID %d (other side %d), state %d (%s), born %d", poll_index, type, this_circid, other_circid, circ->state, circuit_state_to_string[circ->state], (int)circ->timestamp_created); if(circ->cpath) { /* circ starts at this node */ if(circ->state == CIRCUIT_STATE_BUILDING) log(severity,"Building: desired len %d, planned exit node %s.", circ->build_state->desired_path_len, circ->build_state->chosen_exit); for(hop=circ->cpath;hop->next != circ->cpath; hop=hop->next) log(severity,"hop: state %d, addr %x, port %d", hop->state, (unsigned int)hop->addr, (int)hop->port); } } void circuit_dump_by_conn(connection_t *conn, int severity) { circuit_t *circ; connection_t *tmpconn; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->p_conn == conn) circuit_dump_details(severity, circ, conn->poll_index, "App-ward", circ->p_circ_id, circ->n_circ_id); for(tmpconn=circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream) { if(tmpconn == conn) { circuit_dump_details(severity, circ, conn->poll_index, "App-ward", circ->p_circ_id, circ->n_circ_id); } } if(circ->n_conn == conn) circuit_dump_details(severity, circ, conn->poll_index, "Exit-ward", circ->n_circ_id, circ->p_circ_id); for(tmpconn=circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream) { if(tmpconn == conn) { circuit_dump_details(severity, circ, conn->poll_index, "Exit-ward", circ->n_circ_id, circ->p_circ_id); } } } } void circuit_expire_unused_circuits(void) { circuit_t *circ, *tmpcirc; time_t now = time(NULL); circ = global_circuitlist; while(circ) { tmpcirc = circ; circ = circ->next; if(tmpcirc->timestamp_dirty && tmpcirc->timestamp_dirty + options.NewCircuitPeriod < now && !tmpcirc->p_conn && !tmpcirc->p_streams) { log_fn(LOG_DEBUG,"Closing n_circ_id %d",tmpcirc->n_circ_id); circuit_close(tmpcirc); } } } /* Number of consecutive failures so far; should only be touched by * circuit_launch_new and circuit_*_failure_count. */ static int n_circuit_failures = 0; /* Return -1 if you aren't going to try to make a circuit, 0 if you did try. */ int circuit_launch_new(void) { if(!options.SocksPort) /* we're not an application proxy. no need for circuits. */ return -1; if(n_circuit_failures > 5) { /* too many failed circs in a row. don't try. */ // log_fn(LOG_INFO,"%d failures so far, not trying.",n_circuit_failures); return -1; } /* try a circ. if it fails, circuit_close will increment n_circuit_failures */ circuit_establish_circuit(); return 0; } void circuit_increment_failure_count(void) { ++n_circuit_failures; log_fn(LOG_DEBUG,"n_circuit_failures now %d.",n_circuit_failures); } void circuit_reset_failure_count(void) { n_circuit_failures = 0; } int circuit_establish_circuit(void) { routerinfo_t *firsthop; connection_t *n_conn; circuit_t *circ; circ = circuit_new(0, NULL); /* sets circ->p_circ_id and circ->p_conn */ circ->state = CIRCUIT_STATE_OR_WAIT; circ->build_state = onion_new_cpath_build_state(); if (! circ->build_state) { log_fn(LOG_INFO,"Generating cpath length failed."); circuit_close(circ); return -1; } onion_extend_cpath(&circ->cpath, circ->build_state, &firsthop); if(!circ->cpath) { log_fn(LOG_INFO,"Generating first cpath hop failed."); circuit_close(circ); return -1; } /* now see if we're already connected to the first OR in 'route' */ log_fn(LOG_DEBUG,"Looking for firsthop '%s:%u'", firsthop->address,firsthop->or_port); n_conn = connection_twin_get_by_addr_port(firsthop->addr,firsthop->or_port); if(!n_conn || n_conn->state != OR_CONN_STATE_OPEN) { /* not currently connected */ circ->n_addr = firsthop->addr; circ->n_port = firsthop->or_port; if(options.ORPort) { /* we would be connected if he were up. and he's not. */ log_fn(LOG_INFO,"Route's firsthop isn't connected."); circuit_close(circ); return -1; } if(!n_conn) { /* launch the connection */ n_conn = connection_or_connect(firsthop); if(!n_conn) { /* connect failed, forget the whole thing */ log_fn(LOG_INFO,"connect to firsthop failed. Closing."); circuit_close(circ); return -1; } } log_fn(LOG_DEBUG,"connecting in progress (or finished). Good."); return 0; /* return success. The onion/circuit/etc will be taken care of automatically * (may already have been) whenever n_conn reaches OR_CONN_STATE_OPEN. */ } else { /* it (or a twin) is already open. use it. */ circ->n_addr = n_conn->addr; circ->n_port = n_conn->port; circ->n_conn = n_conn; log_fn(LOG_DEBUG,"Conn open. Delivering first onion skin."); if(circuit_send_next_onion_skin(circ) < 0) { log_fn(LOG_INFO,"circuit_send_next_onion_skin failed."); circuit_close(circ); return -1; } } return 0; } /* find circuits that are waiting on me, if any, and get them to send the onion */ void circuit_n_conn_open(connection_t *or_conn) { circuit_t *circ; for(circ=global_circuitlist;circ;circ = circ->next) { if(circ->cpath && circ->n_addr == or_conn->addr && circ->n_port == or_conn->port) { assert(circ->state == CIRCUIT_STATE_OR_WAIT); log_fn(LOG_DEBUG,"Found circ %d, sending onion skin.", circ->n_circ_id); circ->n_conn = or_conn; if(circuit_send_next_onion_skin(circ) < 0) { log_fn(LOG_INFO,"send_next_onion_skin failed; circuit marked for closing."); circuit_close(circ); continue; /* XXX could this be bad, eg if next_onion_skin failed because conn died? */ } } } } int circuit_send_next_onion_skin(circuit_t *circ) { cell_t cell; crypt_path_t *hop; routerinfo_t *router; int r; int circ_id_type; char payload[6+ONIONSKIN_CHALLENGE_LEN]; assert(circ && circ->cpath); if(circ->cpath->state == CPATH_STATE_CLOSED) { assert(circ->n_conn && circ->n_conn->type == CONN_TYPE_OR); log_fn(LOG_DEBUG,"First skin; sending create cell."); circ_id_type = decide_circ_id_type(options.Nickname, circ->n_conn->nickname); circ->n_circ_id = get_unique_circ_id_by_conn(circ->n_conn, circ_id_type); memset(&cell, 0, sizeof(cell_t)); cell.command = CELL_CREATE; cell.circ_id = circ->n_circ_id; if(onion_skin_create(circ->n_conn->onion_pkey, &(circ->cpath->handshake_state), cell.payload) < 0) { log_fn(LOG_WARN,"onion_skin_create (first hop) failed."); return -1; } connection_or_write_cell_to_buf(&cell, circ->n_conn); circ->cpath->state = CPATH_STATE_AWAITING_KEYS; circ->state = CIRCUIT_STATE_BUILDING; log_fn(LOG_DEBUG,"first skin; finished sending create cell."); } else { assert(circ->cpath->state == CPATH_STATE_OPEN); assert(circ->state == CIRCUIT_STATE_BUILDING); log_fn(LOG_DEBUG,"starting to send subsequent skin."); r = onion_extend_cpath(&circ->cpath, circ->build_state, &router); if (r==1) { /* done building the circuit. whew. */ circ->state = CIRCUIT_STATE_OPEN; log_fn(LOG_INFO,"circuit built!"); circuit_reset_failure_count(); /* Tell any AP connections that have been waiting for a new * circuit that one is ready. */ connection_ap_attach_pending(); return 0; } else if (r<0) { log_fn(LOG_INFO,"Unable to extend circuit path."); return -1; } hop = circ->cpath->prev; *(uint32_t*)payload = htonl(hop->addr); *(uint16_t*)(payload+4) = htons(hop->port); if(onion_skin_create(router->onion_pkey, &(hop->handshake_state), payload+6) < 0) { log_fn(LOG_WARN,"onion_skin_create failed."); return -1; } log_fn(LOG_DEBUG,"Sending extend relay cell."); /* send it to hop->prev, because it will transfer * it to a create cell and then send to hop */ if(connection_edge_send_command(NULL, circ, RELAY_COMMAND_EXTEND, payload, sizeof(payload), hop->prev) < 0) return 0; /* circuit is closed */ hop->state = CPATH_STATE_AWAITING_KEYS; } return 0; } /* take the 'extend' cell, pull out addr/port plus the onion skin. Make * sure we're connected to the next hop, and pass it the onion skin in * a create cell. */ int circuit_extend(cell_t *cell, circuit_t *circ) { connection_t *n_conn; int circ_id_type; cell_t newcell; if(circ->n_conn) { log_fn(LOG_WARN,"n_conn already set. Bug/attack. Closing."); return -1; } circ->n_addr = ntohl(*(uint32_t*)(cell->payload+RELAY_HEADER_SIZE)); circ->n_port = ntohs(*(uint16_t*)(cell->payload+RELAY_HEADER_SIZE+4)); n_conn = connection_twin_get_by_addr_port(circ->n_addr,circ->n_port); if(!n_conn || n_conn->type != CONN_TYPE_OR) { /* i've disabled making connections through OPs, but it's definitely * possible here. I'm not sure if it would be a bug or a feature. -RD */ /* note also that this will close circuits where the onion has the same * router twice in a row in the path. i think that's ok. -RD */ struct in_addr in; in.s_addr = htonl(circ->n_addr); log_fn(LOG_INFO,"Next router (%s:%d) not connected. Closing.", inet_ntoa(in), circ->n_port); connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED, NULL, 0, NULL); return 0; } circ->n_addr = n_conn->addr; /* these are different if we found a twin instead */ circ->n_port = n_conn->port; circ->n_conn = n_conn; log_fn(LOG_DEBUG,"n_conn is %s:%u",n_conn->address,n_conn->port); circ_id_type = decide_circ_id_type(options.Nickname, n_conn->nickname); log_fn(LOG_DEBUG,"circ_id_type = %u.",circ_id_type); circ->n_circ_id = get_unique_circ_id_by_conn(circ->n_conn, circ_id_type); if(!circ->n_circ_id) { log_fn(LOG_WARN,"failed to get unique circID."); return -1; } log_fn(LOG_DEBUG,"Chosen circID %u.",circ->n_circ_id); memset(&newcell, 0, sizeof(cell_t)); newcell.command = CELL_CREATE; newcell.circ_id = circ->n_circ_id; memcpy(newcell.payload, cell->payload+RELAY_HEADER_SIZE+6, ONIONSKIN_CHALLENGE_LEN); connection_or_write_cell_to_buf(&newcell, circ->n_conn); return 0; } int circuit_finish_handshake(circuit_t *circ, char *reply) { unsigned char iv[16]; unsigned char keys[40+32]; crypt_path_t *hop; memset(iv, 0, 16); assert(circ->cpath); if(circ->cpath->state == CPATH_STATE_AWAITING_KEYS) hop = circ->cpath; else { for(hop=circ->cpath->next; hop != circ->cpath && hop->state == CPATH_STATE_OPEN; hop=hop->next) ; if(hop == circ->cpath) { /* got an extended when we're all done? */ log_fn(LOG_WARN,"got extended when circ already built? Closing."); return -1; } } assert(hop->state == CPATH_STATE_AWAITING_KEYS); if(onion_skin_client_handshake(hop->handshake_state, reply, keys, 40+32) < 0) { log_fn(LOG_WARN,"onion_skin_client_handshake failed."); return -1; } crypto_dh_free(hop->handshake_state); /* don't need it anymore */ hop->handshake_state = NULL; log_fn(LOG_INFO,"hop %d init digest forward %u, backward %u.", (int)hop, (unsigned)*(uint32_t*)keys, (unsigned)*(uint32_t*)(keys+20)); hop->f_digest = crypto_new_digest_env(CRYPTO_SHA1_DIGEST); crypto_digest_add_bytes(hop->f_digest, keys, 20); hop->b_digest = crypto_new_digest_env(CRYPTO_SHA1_DIGEST); crypto_digest_add_bytes(hop->b_digest, keys+20, 20); log_fn(LOG_DEBUG,"hop %d init cipher forward %u, backward %u.", (int)hop, (unsigned)*(uint32_t*)(keys+40), (unsigned) *(uint32_t*)(keys+40+16)); if (!(hop->f_crypto = crypto_create_init_cipher(CIRCUIT_CIPHER,keys+40,iv,1))) { log(LOG_WARN,"forward cipher initialization failed."); return -1; } if (!(hop->b_crypto = crypto_create_init_cipher(CIRCUIT_CIPHER,keys+40+16,iv,0))) { log(LOG_WARN,"backward cipher initialization failed."); return -1; } hop->state = CPATH_STATE_OPEN; log_fn(LOG_INFO,"finished"); circuit_log_path(LOG_WARN,circ); return 0; } int circuit_truncated(circuit_t *circ, crypt_path_t *layer) { crypt_path_t *victim; connection_t *stream; assert(circ); assert(layer); /* XXX Since we don't ask for truncates currently, getting a truncated * means that a connection broke or an extend failed. For now, * just give up. */ circuit_close(circ); return 0; while(layer->next != circ->cpath) { /* we need to clear out layer->next */ victim = layer->next; log_fn(LOG_DEBUG, "Killing a layer of the cpath."); for(stream = circ->p_streams; stream; stream=stream->next_stream) { if(stream->cpath_layer == victim) { log_fn(LOG_INFO, "Marking stream %d for close.", stream->stream_id); /* no need to send 'end' relay cells, * because the other side's already dead */ stream->marked_for_close = 1; stream->has_sent_end = 1; } } layer->next = victim->next; circuit_free_cpath_node(victim); } log_fn(LOG_INFO, "finished"); return 0; } void assert_cpath_layer_ok(const crypt_path_t *cp) { assert(cp->f_crypto); assert(cp->b_crypto); assert(cp->addr); assert(cp->port); switch(cp->state) { case CPATH_STATE_CLOSED: case CPATH_STATE_OPEN: assert(!cp->handshake_state); break; case CPATH_STATE_AWAITING_KEYS: assert(cp->handshake_state); break; default: assert(0); } assert(cp->package_window >= 0); assert(cp->deliver_window >= 0); } void assert_cpath_ok(const crypt_path_t *cp) { while(cp->prev) cp = cp->prev; while(cp->next) { assert_cpath_layer_ok(cp); /* layers must be in sequence of: "open* awaiting? closed*" */ if (cp->prev) { if (cp->prev->state == CPATH_STATE_OPEN) { assert(cp->state == CPATH_STATE_CLOSED || cp->state == CPATH_STATE_AWAITING_KEYS); } else { assert(cp->state == CPATH_STATE_CLOSED); } } cp = cp->next; } } void assert_circuit_ok(const circuit_t *c) { connection_t *conn; assert(c->n_addr); assert(c->n_port); assert(c->n_conn); assert(c->n_conn->type == CONN_TYPE_OR); if (c->p_conn) assert(c->p_conn->type == CONN_TYPE_OR); for (conn = c->p_streams; conn; conn = conn->next_stream) assert(c->p_conn->type == CONN_TYPE_EXIT); for (conn = c->n_streams; conn; conn = conn->next_stream) assert(conn->type == CONN_TYPE_EXIT); assert(c->deliver_window >= 0); assert(c->package_window >= 0); if (c->state == CIRCUIT_STATE_OPEN) { if (c->cpath) { assert(!c->n_crypto); assert(!c->p_crypto); assert(!c->n_digest); assert(!c->p_digest); } else { assert(c->n_crypto); assert(c->p_crypto); assert(c->n_digest); assert(c->p_digest); } } if (c->cpath) { assert_cpath_ok(c->cpath); } } /* Local Variables: mode:c indent-tabs-mode:nil c-basic-offset:2 End: */