/* 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, int 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 int circuit_resume_edge_reading_helper(connection_t *conn, circuit_t *circ, crypt_path_t *layer_hint); 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); static void circuit_rep_hist_note_result(circuit_t *circ); void circuit_expire_old_circuits(void); static void circuit_is_open(circuit_t *circ); static void circuit_build_failed(circuit_t *circ); static circuit_t *circuit_establish_circuit(uint8_t purpose, const char *exit_nickname); unsigned long stats_n_relay_cells_relayed = 0; unsigned long stats_n_relay_cells_delivered = 0; /********* START VARIABLES **********/ static int circuitlist_len=0; 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; } ++circuitlist_len; } void circuit_remove(circuit_t *circ) { circuit_t *tmpcirc; tor_assert(circ && global_circuitlist); if(global_circuitlist == circ) { global_circuitlist = global_circuitlist->next; --circuitlist_len; return; } for(tmpcirc = global_circuitlist;tmpcirc->next;tmpcirc = tmpcirc->next) { if(tmpcirc->next == circ) { tmpcirc->next = circ->next; --circuitlist_len; return; } } } void circuit_close_all_marked() { circuit_t *tmp,*m; while (global_circuitlist && global_circuitlist->marked_for_close) { tmp = global_circuitlist->next; circuit_free(global_circuitlist); global_circuitlist = tmp; } tmp = global_circuitlist; while (tmp && tmp->next) { if (tmp->next->marked_for_close) { m = tmp->next->next; circuit_free(tmp->next); tmp->next = m; /* Need to check new tmp->next; don't advance tmp. */ } else { /* Advance tmp. */ tmp = tmp->next; } } } circuit_t *circuit_new(uint16_t p_circ_id, connection_t *p_conn) { circuit_t *circ; circ = tor_malloc_zero(sizeof(circuit_t)); circ->magic = CIRCUIT_MAGIC; 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) { tor_assert(circ); tor_assert(circ->magic == CIRCUIT_MAGIC); 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); if (circ->build_state->pending_final_cpath) circuit_free_cpath_node(circ->build_state->pending_final_cpath); } tor_free(circ->build_state); circuit_free_cpath(circ->cpath); if (circ->rend_splice) { circ->rend_splice->rend_splice = NULL; } memset(circ, 0xAA, sizeof(circuit_t)); /* poison memory */ 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; tor_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->marked_for_close) continue; 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->marked_for_close) continue; 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; } /* Return 1 iff 'c' could be returned by circuit_get_best. */ static int circuit_is_acceptable(circuit_t *circ, connection_t *conn, int must_be_open, uint8_t purpose, time_t now) { routerinfo_t *exitrouter; if (!CIRCUIT_IS_ORIGIN(circ)) return 0; /* this circ doesn't start at us */ if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn)) return 0; /* ignore non-open circs */ if (circ->marked_for_close) return 0; /* if this circ isn't our purpose, skip. */ if(purpose == CIRCUIT_PURPOSE_C_REND_JOINED && !must_be_open) { if(circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND && circ->purpose != CIRCUIT_PURPOSE_C_REND_READY && circ->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED && circ->purpose != CIRCUIT_PURPOSE_C_REND_JOINED) return 0; } else if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT && !must_be_open) { if (circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCING && circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) return 0; } else { if(purpose != circ->purpose) return 0; } if(purpose == CIRCUIT_PURPOSE_C_GENERAL) if(circ->timestamp_dirty && circ->timestamp_dirty+options.NewCircuitPeriod < now) return 0; if(conn) { /* decide if this circ is suitable for this conn */ /* for rend circs, circ->cpath->prev is not the last router in the * circuit, it's the magical extra bob hop. so just check the nickname * of the one we meant to finish at. */ exitrouter = router_get_by_nickname(circ->build_state->chosen_exit); if(!exitrouter) { log_fn(LOG_INFO,"Skipping broken circ (exit router vanished)"); return 0; /* this circuit is screwed and doesn't know it yet */ } if(purpose == CIRCUIT_PURPOSE_C_GENERAL) { if(connection_ap_can_use_exit(conn, exitrouter) == ADDR_POLICY_REJECTED) { /* can't exit from this router */ return 0; } } else { /* not general */ if(rend_cmp_service_ids(conn->rend_query, circ->rend_query) && (circ->rend_query[0] || purpose != CIRCUIT_PURPOSE_C_REND_JOINED)) { /* this circ is not for this conn, and it's not suitable * for cannibalizing either */ return 0; } } } return 1; } /* Return 1 iff circuit 'a' is better than circuit 'b' for purpose. Used by * circuit_get_best */ static int circuit_is_better(circuit_t *a, circuit_t *b, uint8_t purpose) { switch(purpose) { case CIRCUIT_PURPOSE_C_GENERAL: /* if it's used but less dirty it's best; * else if it's more recently created it's best */ if(b->timestamp_dirty) { if(a->timestamp_dirty && a->timestamp_dirty > b->timestamp_dirty) return 1; } else { if(a->timestamp_dirty || a->timestamp_created > b->timestamp_created) return 1; } break; case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT: /* the closer it is to ack_wait the better it is */ if(a->purpose > b->purpose) return 1; break; case CIRCUIT_PURPOSE_C_REND_JOINED: /* the closer it is to rend_joined the better it is */ if(a->purpose > b->purpose) return 1; break; } return 0; } /* Find the best circ that conn can use, preferably one which is * dirty. Circ must not be too old. * conn must be defined. * * If must_be_open, ignore circs not in CIRCUIT_STATE_OPEN. * * circ_purpose specifies what sort of circuit we must have. * It can be C_GENERAL, C_INTRODUCE_ACK_WAIT, or C_REND_JOINED. * * If it's REND_JOINED and must_be_open==0, then return the closest * rendezvous-purposed circuit that you can find. * * If it's INTRODUCE_ACK_WAIT and must_be_open==0, then return the * closest introduce-purposed circuit that you can find. */ circuit_t *circuit_get_best(connection_t *conn, int must_be_open, uint8_t purpose) { circuit_t *circ, *best=NULL; time_t now = time(NULL); tor_assert(conn); tor_assert(purpose == CIRCUIT_PURPOSE_C_GENERAL || purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT || purpose == CIRCUIT_PURPOSE_C_REND_JOINED); for (circ=global_circuitlist;circ;circ = circ->next) { if (!circuit_is_acceptable(circ,conn,must_be_open,purpose,now)) continue; /* now this is an acceptable circ to hand back. but that doesn't * mean it's the *best* circ to hand back. try to decide. */ if(!best || circuit_is_better(circ,best,purpose)) best = circ; } return best; } circuit_t *circuit_get_by_rend_query_and_purpose(const char *rend_query, uint8_t purpose) { circuit_t *circ; for (circ = global_circuitlist; circ; circ = circ->next) { if (!circ->marked_for_close && circ->purpose == purpose && !rend_cmp_service_ids(rend_query, circ->rend_query)) return circ; } return NULL; } /* Return the first circuit in global_circuitlist after 'start' whose * rend_pk_digest field is 'digest' and whose purpose is purpose. Returns * NULL if no circuit is found. If 'start' is null, begin at the start of * the list. */ circuit_t *circuit_get_next_by_pk_and_purpose(circuit_t *start, const char *digest, uint8_t purpose) { circuit_t *circ; if (start == NULL) circ = global_circuitlist; else circ = start->next; for( ; circ; circ = circ->next) { if (circ->marked_for_close) continue; if (circ->purpose != purpose) continue; if (!memcmp(circ->rend_pk_digest, digest, DIGEST_LEN)) return circ; } return NULL; } /* Return the circuit waiting for a rendezvous with the provided cookie. * Return NULL if no such circuit is found. */ circuit_t *circuit_get_rendezvous(const char *cookie) { circuit_t *circ; for (circ = global_circuitlist; circ; circ = circ->next) { if (! circ->marked_for_close && circ->purpose == CIRCUIT_PURPOSE_REND_POINT_WAITING && ! memcmp(circ->rend_cookie, cookie, REND_COOKIE_LEN) ) return circ; } return NULL; } #define MIN_SECONDS_BEFORE_EXPIRING_CIRC 30 /* circuits that were born at the end of their second might be expired * after 30.1 seconds; circuits born at the beginning might be expired * after closer to 31 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(time_t now) { circuit_t *victim, *circ = global_circuitlist; while(circ) { victim = circ; circ = circ->next; if(!CIRCUIT_IS_ORIGIN(victim)) continue; /* didn't originate here */ if(victim->marked_for_close) continue; /* don't mess with marked circs */ if(victim->timestamp_created + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now) continue; /* it's young still, don't mess with it */ /* some debug logs, to help track bugs */ if(victim->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING && victim->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) { if(!victim->timestamp_dirty) log_fn(LOG_DEBUG,"Considering %sopen purp %d to %s (circid %d). (clean).", victim->state == CIRCUIT_STATE_OPEN ? "" : "non", victim->purpose, victim->build_state->chosen_exit, victim->n_circ_id); else log_fn(LOG_DEBUG,"Considering %sopen purp %d to %s (circid %d). %d secs since dirty.", victim->state == CIRCUIT_STATE_OPEN ? "" : "non", victim->purpose, victim->build_state->chosen_exit, victim->n_circ_id, (int)(now - victim->timestamp_dirty)); } /* if circ is !open, or if it's open but purpose is a non-finished * intro or rend, then mark it for close */ if(victim->state != CIRCUIT_STATE_OPEN || victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND || victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING || victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO || /* it's a rend_ready circ, but it's already picked a query */ (victim->purpose == CIRCUIT_PURPOSE_C_REND_READY && victim->rend_query[0]) || /* c_rend_ready circs measure age since timestamp_dirty, * because that's set when they switch purposes */ /* rend and intro circs become dirty each time they * make an introduction attempt. so timestamp_dirty * will reflect the time since the last attempt. */ ((victim->purpose == CIRCUIT_PURPOSE_C_REND_READY || victim->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED || victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) && victim->timestamp_dirty + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now)) { if(victim->n_conn) log_fn(LOG_INFO,"Abandoning circ %s:%d:%d (state %d:%s, purpose %d)", victim->n_conn->address, victim->n_port, victim->n_circ_id, victim->state, circuit_state_to_string[victim->state], victim->purpose); else log_fn(LOG_INFO,"Abandoning circ %d (state %d:%s, purpose %d)", victim->n_circ_id, victim->state, circuit_state_to_string[victim->state], victim->purpose); circuit_log_path(LOG_INFO,victim); circuit_mark_for_close(victim); } } } /* count the number of circs starting at us that aren't open */ int circuit_count_building(uint8_t purpose) { circuit_t *circ; int num=0; for(circ=global_circuitlist;circ;circ = circ->next) { if(CIRCUIT_IS_ORIGIN(circ) && circ->state != CIRCUIT_STATE_OPEN && circ->purpose == purpose && !circ->marked_for_close) num++; } return num; } #define MIN_CIRCUITS_HANDLING_STREAM 2 /* return 1 if at least MIN_CIRCUITS_HANDLING_STREAM non-open * general-purpose 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; time_t now = time(NULL); for(circ=global_circuitlist;circ;circ = circ->next) { if(CIRCUIT_IS_ORIGIN(circ) && circ->state != CIRCUIT_STATE_OPEN && !circ->marked_for_close && circ->purpose == CIRCUIT_PURPOSE_C_GENERAL && (!circ->timestamp_dirty || circ->timestamp_dirty + options.NewCircuitPeriod < now)) { 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; } static circuit_t * circuit_get_youngest_clean_open(uint8_t purpose) { circuit_t *circ; circuit_t *youngest=NULL; for(circ=global_circuitlist;circ;circ = circ->next) { if(CIRCUIT_IS_ORIGIN(circ) && circ->state == CIRCUIT_STATE_OPEN && !circ->marked_for_close && circ->purpose == purpose && !circ->timestamp_dirty && (!youngest || youngest->timestamp_created < circ->timestamp_created)) youngest = circ; } return youngest; } /* Build a new test circuit every 5 minutes */ #define TESTING_CIRCUIT_INTERVAL 300 /* this function is called once a second. its job is to make sure * all services we offer have enough circuits available. Some * services just want enough circuits for current tasks, whereas * others want a minimum set of idle circuits hanging around. */ void circuit_build_needed_circs(time_t now) { static long time_to_new_circuit = 0; circuit_t *circ; /* launch a new circ for any pending streams that need one */ connection_ap_attach_pending(); /* make sure any hidden services have enough intro points */ rend_services_introduce(); circ = circuit_get_youngest_clean_open(CIRCUIT_PURPOSE_C_GENERAL); if(time_to_new_circuit < now) { circuit_reset_failure_count(); time_to_new_circuit = now + options.NewCircuitPeriod; if(options.SocksPort) client_dns_clean(); circuit_expire_old_circuits(); if(options.RunTesting && circ && circ->timestamp_created + TESTING_CIRCUIT_INTERVAL < now) { log_fn(LOG_INFO,"Creating a new testing circuit."); circuit_launch_new(CIRCUIT_PURPOSE_C_GENERAL, NULL); } } #define CIRCUIT_MIN_BUILDING_GENERAL 3 /* if there's no open circ, and less than 3 are on the way, * go ahead and try another. */ if(!circ && circuit_count_building(CIRCUIT_PURPOSE_C_GENERAL) < CIRCUIT_MIN_BUILDING_GENERAL) { circuit_launch_new(CIRCUIT_PURPOSE_C_GENERAL, NULL); } /* XXX count idle rendezvous circs and build more */ } /* 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 relay encryption"); 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; tor_assert(cell && circ); tor_assert(cell_direction == CELL_DIRECTION_OUT || cell_direction == CELL_DIRECTION_IN); if (circ->marked_for_close) return 0; 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 away from origin."); if (connection_edge_process_relay_cell(cell, circ, conn, NULL) < 0) { log_fn(LOG_WARN,"connection_edge_process_relay_cell (away from origin) failed."); return -1; } } if(cell_direction == CELL_DIRECTION_IN) { ++stats_n_relay_cells_delivered; log_fn(LOG_DEBUG,"Sending to origin."); if (connection_edge_process_relay_cell(cell, circ, conn, layer_hint) < 0) { log_fn(LOG_WARN,"connection_edge_process_relay_cell (at origin) 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) { if (circ->rend_splice && cell_direction == CELL_DIRECTION_OUT) { tor_assert(circ->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED); tor_assert(circ->rend_splice->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED); cell->circ_id = circ->rend_splice->p_circ_id; if (circuit_receive_relay_cell(cell, circ->rend_splice, CELL_DIRECTION_IN)<0) { log_fn(LOG_WARN, "Error relaying cell across rendezvous; closing circuits"); circuit_mark_for_close(circ); /* XXXX Do this here, or just return -1? */ return -1; } return 0; } log_fn(LOG_WARN,"Didn't recognize cell, but circ stops here! Closing circ."); 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, int cell_direction, crypt_path_t **layer_hint, char *recognized) { crypt_path_t *thishop; relay_header_t rh; tor_assert(circ && cell && recognized); tor_assert(cell_direction == CELL_DIRECTION_IN || cell_direction == CELL_DIRECTION_OUT); if(cell_direction == CELL_DIRECTION_IN) { if(CIRCUIT_IS_ORIGIN(circ)) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */ tor_assert(circ->cpath); thishop = circ->cpath; if(thishop->state != CPATH_STATE_OPEN) { log_fn(LOG_WARN,"Relay cell before first created cell? Closing."); return -1; } do { /* Remember: cpath is in forward order, that is, first hop first. */ tor_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. Closing."); return -1; } 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: 1) encrypt it to the right conn 2) 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_WARN,"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 { tor_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_WARN,"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; /* IN or OUT cells could have come from either direction, now * that we allow rendezvous *to* an OP. */ for(tmpconn = circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream) { if(rh.stream_id == tmpconn->stream_id) { log_fn(LOG_DEBUG,"found conn for stream %d.", rh.stream_id); if(cell_direction == CELL_DIRECTION_OUT || connection_edge_is_rendezvous_stream(tmpconn)) return tmpconn; } } for(tmpconn = circ->p_streams; 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; } } return NULL; /* probably a begin relay cell */ } void circuit_resume_edge_reading(circuit_t *circ, crypt_path_t *layer_hint) { log_fn(LOG_DEBUG,"resuming"); /* have to check both n_streams and p_streams, to handle rendezvous */ if(circuit_resume_edge_reading_helper(circ->n_streams, circ, layer_hint) >= 0) circuit_resume_edge_reading_helper(circ->p_streams, circ, layer_hint); } static int circuit_resume_edge_reading_helper(connection_t *conn, circuit_t *circ, crypt_path_t *layer_hint) { for( ; conn; conn=conn->next_stream) { if((!layer_hint && conn->package_window > 0) || (layer_hint && conn->package_window > 0 && conn->cpath_layer == layer_hint)) { connection_start_reading(conn); /* handle whatever might still be on the inbuf */ connection_edge_package_raw_inbuf(conn); /* 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, layer_hint)) return -1; } } return 0; } /* 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, crypt_path_t *layer_hint) { connection_t *conn = NULL; log_fn(LOG_DEBUG,"considering"); if(!layer_hint && circ->package_window <= 0) { log_fn(LOG_DEBUG,"yes, not-at-origin. stopped."); for(conn = circ->n_streams; conn; conn=conn->next_stream) connection_stop_reading(conn); return -1; } else if(layer_hint && layer_hint->package_window <= 0) { log_fn(LOG_DEBUG,"yes, at-origin. stopped."); for(conn = circ->n_streams; conn; conn=conn->next_stream) if(conn->cpath_layer == layer_hint) connection_stop_reading(conn); for(conn = circ->p_streams; conn; conn=conn->next_stream) if(conn->cpath_layer == layer_hint) connection_stop_reading(conn); return -1; } return 0; } void circuit_consider_sending_sendme(circuit_t *circ, crypt_path_t *layer_hint) { // log_fn(LOG_INFO,"Considering: layer_hint is %s", // layer_hint ? "defined" : "null"); while((layer_hint ? layer_hint->deliver_window : circ->deliver_window) < CIRCWINDOW_START - CIRCWINDOW_INCREMENT) { log_fn(LOG_DEBUG,"Queueing circuit sendme."); if(layer_hint) 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. Circuit's closed."); return; /* the circuit's closed, don't continue */ } } } int _circuit_mark_for_close(circuit_t *circ) { connection_t *conn; assert_circuit_ok(circ); if (circ->marked_for_close < 0) return -1; if(circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) { onion_pending_remove(circ); } /* If the circuit ever became OPEN, we sent it to the reputation history * module then. If it isn't OPEN, we send it there now to remember which * links worked and which didn't. */ if (circ->state != CIRCUIT_STATE_OPEN) { if(CIRCUIT_IS_ORIGIN(circ)) circuit_build_failed(circ); /* take actions if necessary */ circuit_rep_hist_note_result(circ); } if (circ->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) { tor_assert(circ->state == CIRCUIT_STATE_OPEN); /* treat this like getting a nack from it */ log_fn(LOG_INFO,"Failed intro circ %s to %s (awaiting ack). Removing from descriptor.", circ->rend_query, circ->build_state->chosen_exit); rend_client_remove_intro_point(circ->build_state->chosen_exit, circ->rend_query); } 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_edge_destroy(circ->n_circ_id, conn); } if(circ->p_conn) connection_send_destroy(circ->p_circ_id, circ->p_conn); for(conn=circ->p_streams; conn; conn=conn->next_stream) { connection_edge_destroy(circ->p_circ_id, conn); } circ->marked_for_close = 1; if (circ->rend_splice && !circ->rend_splice->marked_for_close) { /* do this after marking this circuit, to avoid infinite recursion. */ circuit_mark_for_close(circ->rend_splice); circ->rend_splice = NULL; } return 0; } void circuit_detach_stream(circuit_t *circ, connection_t *conn) { connection_t *prevconn; tor_assert(circ && 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?"); tor_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_mark_for_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_WARN,"Edge connection hasn't sent end yet? Bug."); connection_mark_for_close(conn, END_STREAM_REASON_MISC); } circuit_detach_stream(circ, conn); } /* end switch */ } void circuit_log_path(int severity, circuit_t *circ) { char buf[1024]; char *s = buf; struct crypt_path_t *hop; char *states[] = {"closed", "waiting for keys", "open"}; routerinfo_t *router; tor_assert(CIRCUIT_IS_ORIGIN(circ) && circ->cpath); snprintf(s, sizeof(buf)-1, "circ (length %d, exit %s): ", circ->build_state->desired_path_len, circ->build_state->chosen_exit); hop=circ->cpath; do { s = buf + strlen(buf); router = router_get_by_addr_port(hop->addr,hop->port); if(router) { snprintf(s, sizeof(buf) - (s - buf), "%s(%s) ", router->nickname, states[hop->state]); } else { if(circ->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) { snprintf(s, sizeof(buf) - (s - buf), "(rendjoin hop)"); } else { snprintf(s, sizeof(buf) - (s - buf), "UNKNOWN "); } } hop=hop->next; } while(hop!=circ->cpath); log_fn(severity,"%s",buf); } /* Tell the rep(utation)hist(ory) module about the status of the links * in circ. Hops that have become OPEN are marked as successfully * extended; the _first_ hop that isn't open (if any) is marked as * unable to extend. */ static void circuit_rep_hist_note_result(circuit_t *circ) { struct crypt_path_t *hop; char *prev_nickname = NULL; routerinfo_t *router; hop = circ->cpath; if(!hop) { /* XXX * if !hop, then we're not the beginning of this circuit. * for now, just forget about it. later, we should remember when * extends-through-us failed, too. */ return; } if (options.ORPort) { prev_nickname = options.Nickname; } do { router = router_get_by_addr_port(hop->addr,hop->port); if (router) { if (prev_nickname) { if (hop->state == CPATH_STATE_OPEN) rep_hist_note_extend_succeeded(prev_nickname, router->nickname); else { rep_hist_note_extend_failed(prev_nickname, router->nickname); break; } } prev_nickname = router->nickname; } else { prev_nickname = NULL; } hop=hop->next; } while (hop!=circ->cpath); } 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(CIRCUIT_IS_ORIGIN(circ)) { /* 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 0x%.8x, 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); } } } } /* Don't keep more than 10 unused open circuits around. */ #define MAX_UNUSED_OPEN_CIRCUITS 10 void circuit_expire_old_circuits(void) { circuit_t *circ; time_t now = time(NULL); smartlist_t *unused_open_circs; int i; unused_open_circs = smartlist_create(); for (circ = global_circuitlist; circ; circ = circ->next) { if (circ->marked_for_close) continue; /* If the circuit has been dirty for too long, and there are no streams * on it, mark it for close. */ if (circ->timestamp_dirty && circ->timestamp_dirty + options.NewCircuitPeriod < now && !circ->p_conn && /* we're the origin */ !circ->p_streams /* nothing attached */ ) { log_fn(LOG_DEBUG,"Closing n_circ_id %d (dirty %d secs ago, purp %d)",circ->n_circ_id, (int)(now - circ->timestamp_dirty), circ->purpose); /* (only general and purpose_c circs can get dirty) */ tor_assert(!circ->n_streams); tor_assert(circ->purpose <= CIRCUIT_PURPOSE_C_REND_JOINED); circuit_mark_for_close(circ); } else if (!circ->timestamp_dirty && CIRCUIT_IS_ORIGIN(circ) && circ->state == CIRCUIT_STATE_OPEN && circ->purpose == CIRCUIT_PURPOSE_C_GENERAL) { /* Also, gather a list of open unused general circuits that we created. * Because we add elements to the front of global_circuitlist, * the last elements of unused_open_circs will be the oldest * ones. */ smartlist_add(unused_open_circs, circ); } } for (i = MAX_UNUSED_OPEN_CIRCUITS; i < smartlist_len(unused_open_circs); ++i) { circuit_t *circ = smartlist_get(unused_open_circs, i); log_fn(LOG_DEBUG,"Expiring excess clean circ (n_circ_id %d, purp %d)", circ->n_circ_id, circ->purpose); circuit_mark_for_close(circ); } smartlist_free(unused_open_circs); } static void circuit_is_open(circuit_t *circ) { switch(circ->purpose) { case CIRCUIT_PURPOSE_C_ESTABLISH_REND: rend_client_rendcirc_is_open(circ); break; case CIRCUIT_PURPOSE_C_INTRODUCING: rend_client_introcirc_is_open(circ); break; case CIRCUIT_PURPOSE_C_GENERAL: /* Tell any AP connections that have been waiting for a new * circuit that one is ready. */ connection_ap_attach_pending(); break; case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* at Bob, waiting for introductions */ rend_service_intro_is_ready(circ); break; case CIRCUIT_PURPOSE_S_CONNECT_REND: /* at Bob, connecting to rend point */ rend_service_rendezvous_is_ready(circ); break; default: log_fn(LOG_ERR,"unhandled purpose %d",circ->purpose); tor_assert(0); } } /* Called whenever a circuit could not be successfully built. */ static void circuit_build_failed(circuit_t *circ) { /* we should examine circ and see if it failed because of * the last hop or an earlier hop. then use this info below. */ int failed_at_last_hop = 0; /* If the last hop isn't open, and the second-to-last is, we failed * at the last hop. */ if (circ->cpath && circ->cpath->prev->state != CPATH_STATE_OPEN && circ->cpath->prev->prev->state == CPATH_STATE_OPEN) { failed_at_last_hop = 1; } switch(circ->purpose) { case CIRCUIT_PURPOSE_C_GENERAL: if (circ->state != CIRCUIT_STATE_OPEN) { /* 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(); } break; case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO: /* at Bob, waiting for introductions */ if (circ->state != CIRCUIT_STATE_OPEN) { circuit_increment_failure_count(); } /* no need to care here, because bob will rebuild intro * points periodically. */ break; case CIRCUIT_PURPOSE_C_INTRODUCING: /* at Alice, connecting to intro point */ /* Don't increment failure count, since Bob may have picked * the introduction point maliciously */ /* Alice will pick a new intro point when this one dies, if * the stream in question still cares. No need to act here. */ break; case CIRCUIT_PURPOSE_C_ESTABLISH_REND: /* at Alice, waiting for Bob */ if (circ->state != CIRCUIT_STATE_OPEN) { circuit_increment_failure_count(); } /* Alice will pick a new rend point when this one dies, if * the stream in question still cares. No need to act here. */ break; case CIRCUIT_PURPOSE_S_CONNECT_REND: /* at Bob, connecting to rend point */ /* Don't increment failure count, since Alice may have picked * the rendezvous point maliciously */ if (failed_at_last_hop) { log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s. Sucks to be Alice.", circ->build_state->chosen_exit); } else { log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s, because an earlier node failed.", circ->build_state->chosen_exit); rend_service_relaunch_rendezvous(circ); } break; default: /* Other cases are impossible, since this function is only called with * unbuilt circuits. */ tor_assert(0); } } /* Number of consecutive failures so far; should only be touched by * circuit_launch_new and circuit_*_failure_count. */ static int n_circuit_failures = 0; /* Don't retry launching a new circuit if we try this many times with no * success. */ #define MAX_CIRCUIT_FAILURES 5 /* Launch a new circuit and return a pointer to it. Return NULL if you failed. */ circuit_t *circuit_launch_new(uint8_t purpose, const char *exit_nickname) { if (n_circuit_failures > MAX_CIRCUIT_FAILURES) { /* too many failed circs in a row. don't try. */ // log_fn(LOG_INFO,"%d failures so far, not trying.",n_circuit_failures); return NULL; } /* try a circ. if it fails, circuit_mark_for_close will increment n_circuit_failures */ return circuit_establish_circuit(purpose, exit_nickname); } 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; } static circuit_t *circuit_establish_circuit(uint8_t purpose, const char *exit_nickname) { 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(purpose, exit_nickname); circ->purpose = purpose; if (! circ->build_state) { log_fn(LOG_INFO,"Generating cpath failed."); circuit_mark_for_close(circ); return NULL; } onion_extend_cpath(&circ->cpath, circ->build_state, &firsthop); if(!CIRCUIT_IS_ORIGIN(circ)) { log_fn(LOG_INFO,"Generating first cpath hop failed."); circuit_mark_for_close(circ); return NULL; } /* 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(!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_mark_for_close(circ); return NULL; } } log_fn(LOG_DEBUG,"connecting in progress (or finished). Good."); /* return success. The onion/circuit/etc will be taken care of automatically * (may already have been) whenever n_conn reaches OR_CONN_STATE_OPEN. */ return circ; } 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_mark_for_close(circ); return NULL; } } return circ; } /* 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->marked_for_close) continue; if(CIRCUIT_IS_ORIGIN(circ) && circ->n_addr == or_conn->addr && circ->n_port == or_conn->port) { tor_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_mark_for_close(circ); continue; /* XXX could this be bad, eg if next_onion_skin failed because conn died? */ } } } } extern int has_completed_circuit; 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[2+4+ONIONSKIN_CHALLENGE_LEN]; tor_assert(circ && CIRCUIT_IS_ORIGIN(circ)); if(circ->cpath->state == CPATH_STATE_CLOSED) { tor_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; router = router_get_by_nickname(circ->n_conn->nickname); if (!router) { log_fn(LOG_WARN,"Couldn't find routerinfo for %s", circ->n_conn->nickname); return -1; } if(onion_skin_create(router->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 { tor_assert(circ->cpath->state == CPATH_STATE_OPEN); tor_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(); if(!has_completed_circuit) { has_completed_circuit=1; log_fn(LOG_NOTICE,"Tor has successfully opened a circuit. Looks like it's working."); } circuit_rep_hist_note_result(circ); circuit_is_open(circ); /* do other actions as necessary */ 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(get_uint32(cell->payload+RELAY_HEADER_SIZE)); circ->n_port = ntohs(get_uint16(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. * * 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. */ 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); #if 0 /* if we do truncateds, no need to kill circ */ connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED, NULL, 0, NULL); return 0; #endif circuit_mark_for_close(circ); 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+2+4, ONIONSKIN_CHALLENGE_LEN); connection_or_write_cell_to_buf(&newcell, circ->n_conn); return 0; } /* Initialize cpath->{f|b}_{crypto|digest} from the key material in * key_data. key_data must contain CPATH_KEY_MATERIAL bytes, which are * used as follows: * 20 to initialize f_digest * 20 to initialize b_digest * 16 to key f_crypto * 16 to key b_crypto * * (If 'reverse' is true, then f_XX and b_XX are swapped.) */ int circuit_init_cpath_crypto(crypt_path_t *cpath, char *key_data, int reverse) { crypto_digest_env_t *tmp_digest; crypto_cipher_env_t *tmp_crypto; tor_assert(cpath && key_data); tor_assert(!(cpath->f_crypto || cpath->b_crypto || cpath->f_digest || cpath->b_digest)); log_fn(LOG_DEBUG,"hop init digest forward 0x%.8x, backward 0x%.8x.", (unsigned int)*(uint32_t*)key_data, (unsigned int)*(uint32_t*)(key_data+20)); cpath->f_digest = crypto_new_digest_env(); crypto_digest_add_bytes(cpath->f_digest, key_data, DIGEST_LEN); cpath->b_digest = crypto_new_digest_env(); crypto_digest_add_bytes(cpath->b_digest, key_data+DIGEST_LEN, DIGEST_LEN); log_fn(LOG_DEBUG,"hop init cipher forward 0x%.8x, backward 0x%.8x.", (unsigned int)*(uint32_t*)(key_data+40), (unsigned int)*(uint32_t*)(key_data+40+16)); if (!(cpath->f_crypto = crypto_create_init_cipher(key_data+(2*DIGEST_LEN),1))) { log(LOG_WARN,"forward cipher initialization failed."); return -1; } if (!(cpath->b_crypto = crypto_create_init_cipher(key_data+(2*DIGEST_LEN)+CIPHER_KEY_LEN,0))) { log(LOG_WARN,"backward cipher initialization failed."); return -1; } if (reverse) { tmp_digest = cpath->f_digest; cpath->f_digest = cpath->b_digest; cpath->b_digest = tmp_digest; tmp_crypto = cpath->f_crypto; cpath->f_crypto = cpath->b_crypto; cpath->b_crypto = tmp_crypto; } return 0; } int circuit_finish_handshake(circuit_t *circ, char *reply) { unsigned char keys[CPATH_KEY_MATERIAL_LEN]; crypt_path_t *hop; tor_assert(CIRCUIT_IS_ORIGIN(circ)); 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; } } tor_assert(hop->state == CPATH_STATE_AWAITING_KEYS); if(onion_skin_client_handshake(hop->handshake_state, reply, keys, DIGEST_LEN*2+CIPHER_KEY_LEN*2) < 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; /* Remember hash of g^xy */ memcpy(hop->handshake_digest, reply+DH_KEY_LEN, DIGEST_LEN); if (circuit_init_cpath_crypto(hop, keys, 0)<0) { return -1; } hop->state = CPATH_STATE_OPEN; log_fn(LOG_INFO,"finished"); circuit_log_path(LOG_INFO,circ); return 0; } int circuit_truncated(circuit_t *circ, crypt_path_t *layer) { crypt_path_t *victim; connection_t *stream; tor_assert(circ && CIRCUIT_IS_ORIGIN(circ)); tor_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_mark_for_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 */ connection_mark_for_close(stream,0); } } 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) { tor_assert(cp->f_crypto); tor_assert(cp->b_crypto); // tor_assert(cp->addr); /* these are zero for rendezvous extra-hops */ // tor_assert(cp->port); switch(cp->state) { case CPATH_STATE_CLOSED: case CPATH_STATE_OPEN: tor_assert(!cp->handshake_state); break; case CPATH_STATE_AWAITING_KEYS: tor_assert(cp->handshake_state); break; default: tor_assert(0); } tor_assert(cp->package_window >= 0); tor_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) { tor_assert(cp->state == CPATH_STATE_CLOSED || cp->state == CPATH_STATE_AWAITING_KEYS); } else { tor_assert(cp->state == CPATH_STATE_CLOSED); } } cp = cp->next; } } void assert_circuit_ok(const circuit_t *c) { connection_t *conn; tor_assert(c); tor_assert(c->magic == CIRCUIT_MAGIC); tor_assert(c->purpose >= _CIRCUIT_PURPOSE_MIN && c->purpose <= _CIRCUIT_PURPOSE_MAX); if (c->n_conn) tor_assert(c->n_conn->type == CONN_TYPE_OR); if (c->p_conn) tor_assert(c->p_conn->type == CONN_TYPE_OR); for (conn = c->p_streams; conn; conn = conn->next_stream) tor_assert(conn->type == CONN_TYPE_AP); for (conn = c->n_streams; conn; conn = conn->next_stream) tor_assert(conn->type == CONN_TYPE_EXIT); tor_assert(c->deliver_window >= 0); tor_assert(c->package_window >= 0); if (c->state == CIRCUIT_STATE_OPEN) { if (c->cpath) { tor_assert(CIRCUIT_IS_ORIGIN(c)); tor_assert(!c->n_crypto); tor_assert(!c->p_crypto); tor_assert(!c->n_digest); tor_assert(!c->p_digest); } else { tor_assert(!CIRCUIT_IS_ORIGIN(c)); tor_assert(c->n_crypto); tor_assert(c->p_crypto); tor_assert(c->n_digest); tor_assert(c->p_digest); } } if (c->cpath) { //XXX assert_cpath_ok(c->cpath); } if (c->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED) { if (!c->marked_for_close) { tor_assert(c->rend_splice); tor_assert(c->rend_splice->rend_splice == c); } tor_assert(c->rend_splice != c); } else { tor_assert(!c->rend_splice); } } /* Local Variables: mode:c indent-tabs-mode:nil c-basic-offset:2 End: */