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- /* 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) < 0) {
- /* 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 3
- /* circuits that were born at the end of their second might be expired
- * after 3.1 seconds; circuits born at the beginning might be expired
- * after closer to 4 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_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) >= 0)
- 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) {
- uint32_t integrity;
- relay_header_t rh;
- crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE);
- crypto_digest_get_digest(digest, (char *)&integrity, 4);
- log_fn(LOG_DEBUG,"Putting digest of %u into relay cell.",integrity);
- relay_header_unpack(&rh, cell->payload);
- rh.integrity = integrity;
- 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) {
- uint32_t received_integrity, calculated_integrity;
- relay_header_t rh;
- crypto_digest_env_t *backup_digest=NULL;
- backup_digest = crypto_digest_dup(digest);
- relay_header_unpack(&rh, cell->payload);
- received_integrity = rh.integrity;
- rh.integrity = 0;
- relay_header_pack(cell->payload, &rh);
- log_fn(LOG_DEBUG,"Reading digest of %u from relay cell.",received_integrity);
- crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE);
- crypto_digest_get_digest(digest, (char *)&calculated_integrity, 4);
- if(received_integrity != calculated_integrity) {
- 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 */
- rh.integrity = received_integrity;
- 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_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;
- connection_t *prevconn;
- 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.");
- }
- 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 */
- } /* end switch */
- }
- 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");
- 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:
- */
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