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- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. */
- /* See LICENSE for licensing information */
- /* $Id$ */
- const char circuitbuild_c_id[] =
- "$Id$";
- /**
- * \file circuitbuild.c
- * \brief The actual details of building circuits.
- **/
- #include "or.h"
- /********* START VARIABLES **********/
- /** A global list of all circuits at this hop. */
- extern circuit_t *global_circuitlist;
- /** An entry_guard_t represents our information about a chosen long-term
- * first hop, known as a "helper" node in the literature. We can't just
- * use a routerinfo_t, since we want to remember these even when we
- * don't have a directory. */
- typedef struct {
- char nickname[MAX_NICKNAME_LEN+1];
- char identity[DIGEST_LEN];
- uint8_t made_contact; /**< 0 if we have never connected to this router,
- * 1 if we have. */
- time_t down_since; /**< 0 if this router is currently up, or the time at
- * which it was observed to go down. */
- time_t unlisted_since; /**< 0 if this router is currently listed, or the
- * time at which it became unlisted */
- } entry_guard_t;
- /** A list of our chosen entry guards. */
- static smartlist_t *entry_guards = NULL;
- /** A value of 1 means that the entry_guards list has changed
- * and those changes need to be flushed to disk. */
- static int entry_guards_dirty = 0;
- /********* END VARIABLES ************/
- static int circuit_deliver_create_cell(circuit_t *circ,
- uint8_t cell_type, char *payload);
- static int onion_pick_cpath_exit(circuit_t *circ, extend_info_t *exit);
- static crypt_path_t *onion_next_hop_in_cpath(crypt_path_t *cpath);
- static int onion_extend_cpath(uint8_t purpose, crypt_path_t **head_ptr,
- cpath_build_state_t *state);
- static int count_acceptable_routers(smartlist_t *routers);
- static int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
- static routerinfo_t *choose_random_entry(cpath_build_state_t *state);
- static void entry_guards_changed(void);
- /** Iterate over values of circ_id, starting from conn-\>next_circ_id,
- * and with the high bit specified by circ_id_type (see
- * decide_circ_id_type()), until we get a circ_id that is not in use
- * by any other circuit on that conn.
- *
- * Return it, or 0 if can't get a unique circ_id.
- */
- static uint16_t
- get_unique_circ_id_by_conn(connection_t *conn)
- {
- uint16_t test_circ_id;
- uint16_t attempts=0;
- uint16_t high_bit;
- tor_assert(conn);
- tor_assert(conn->type == CONN_TYPE_OR);
- high_bit = (conn->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 opportunity.
- */
- warn(LD_CIRC,"No unused circ IDs. Failing.");
- return 0;
- }
- test_circ_id |= high_bit;
- } while (circuit_id_used_on_conn(test_circ_id, conn));
- return test_circ_id;
- }
- /** If <b>verbose</b> is false, allocate and return a comma-separated
- * list of the currently built elements of circuit_t. If
- * <b>verbose</b> is true, also list information about link status in
- * a more verbose format using spaces.
- */
- char *
- circuit_list_path(circuit_t *circ, int verbose)
- {
- crypt_path_t *hop;
- smartlist_t *elements;
- const char *states[] = {"closed", "waiting for keys", "open"};
- char buf[128];
- char *s;
- tor_assert(CIRCUIT_IS_ORIGIN(circ));
- elements = smartlist_create();
- if (verbose) {
- const char *nickname = build_state_get_exit_nickname(circ->build_state);
- tor_snprintf(buf, sizeof(buf), "%s%s circ (length %d%s%s):",
- circ->build_state->is_internal ? "internal" : "exit",
- circ->build_state->need_uptime ? " (high-uptime)" : "",
- circ->build_state->desired_path_len,
- circ->state == CIRCUIT_STATE_OPEN ? "" : ", exit ",
- circ->state == CIRCUIT_STATE_OPEN ? "" :
- (nickname?nickname:"*unnamed*"));
- smartlist_add(elements, tor_strdup(buf));
- }
- hop = circ->cpath;
- do {
- const char *elt;
- if (!hop)
- break;
- if (!verbose && hop->state != CPATH_STATE_OPEN)
- break;
- if (!hop->extend_info)
- break;
- elt = hop->extend_info->nickname;
- tor_assert(elt);
- if (verbose) {
- size_t len = strlen(elt)+2+strlen(states[hop->state])+1;
- char *v = tor_malloc(len);
- tor_assert(hop->state <= 2);
- tor_snprintf(v,len,"%s(%s)",elt,states[hop->state]);
- smartlist_add(elements, v);
- } else {
- smartlist_add(elements, tor_strdup(elt));
- }
- hop = hop->next;
- } while (hop != circ->cpath);
- s = smartlist_join_strings(elements, verbose?" ":",", 0, NULL);
- SMARTLIST_FOREACH(elements, char*, cp, tor_free(cp));
- smartlist_free(elements);
- return s;
- }
- /** Log, at severity <b>severity</b>, the nicknames of each router in
- * circ's cpath. Also log the length of the cpath, and the intended
- * exit point.
- */
- void
- circuit_log_path(int severity, unsigned int domain, circuit_t *circ)
- {
- char *s = circuit_list_path(circ,1);
- log(severity,domain,"%s",s);
- tor_free(s);
- }
- /** 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.
- */
- void
- circuit_rep_hist_note_result(circuit_t *circ)
- {
- crypt_path_t *hop;
- char *prev_digest = 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 (server_mode(get_options())) {
- routerinfo_t *me = router_get_my_routerinfo();
- tor_assert(me);
- prev_digest = me->cache_info.identity_digest;
- }
- do {
- router = router_get_by_digest(hop->extend_info->identity_digest);
- if (router) {
- if (prev_digest) {
- if (hop->state == CPATH_STATE_OPEN)
- rep_hist_note_extend_succeeded(prev_digest,
- router->cache_info.identity_digest);
- else {
- rep_hist_note_extend_failed(prev_digest,
- router->cache_info.identity_digest);
- break;
- }
- }
- prev_digest = router->cache_info.identity_digest;
- } else {
- prev_digest = NULL;
- }
- hop=hop->next;
- } while (hop!=circ->cpath);
- }
- /** A helper function for circuit_dump_by_conn() below. Log a bunch
- * of information about circuit <b>circ</b>.
- */
- static void
- circuit_dump_details(int severity, circuit_t *circ, int poll_index,
- const char *type, int this_circid, int other_circid)
- {
- log(severity, LD_CIRC, "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 */
- circuit_log_path(severity, LD_CIRC, circ);
- }
- }
- /** Log, at severity <b>severity</b>, information about each circuit
- * that is connected to <b>conn</b>.
- */
- 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->marked_for_close)
- continue;
- 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);
- }
- }
- if (!circ->n_conn && circ->n_addr && circ->n_port &&
- circ->n_addr == conn->addr &&
- circ->n_port == conn->port &&
- !memcmp(conn->identity_digest, circ->n_conn_id_digest, DIGEST_LEN)) {
- circuit_dump_details(severity, circ, conn->poll_index,
- (circ->state == CIRCUIT_STATE_OPEN &&
- !CIRCUIT_IS_ORIGIN(circ)) ?
- "Endpoint" : "Pending",
- circ->n_circ_id, circ->p_circ_id);
- }
- }
- }
- /** Pick all the entries in our cpath. Stop and return 0 when we're
- * happy, or return -1 if an error occurs. */
- static int
- onion_populate_cpath(circuit_t *circ)
- {
- int r;
- again:
- r = onion_extend_cpath(circ->purpose, &circ->cpath, circ->build_state);
- // || !CIRCUIT_IS_ORIGIN(circ)) { // wtf? -rd
- if (r < 0) {
- info(LD_CIRC,"Generating cpath hop failed.");
- return -1;
- }
- if (r == 0)
- goto again;
- return 0; /* if r == 1 */
- }
- /** Create and return a new circuit. Initialize its purpose and
- * build-state based on our arguments. */
- circuit_t *
- circuit_init(uint8_t purpose, int need_uptime, int need_capacity, int internal)
- {
- /* sets circ->p_circ_id and circ->p_conn */
- circuit_t *circ = circuit_new(0, NULL);
- circuit_set_state(circ, CIRCUIT_STATE_OR_WAIT);
- circ->build_state = tor_malloc_zero(sizeof(cpath_build_state_t));
- circ->build_state->need_uptime = need_uptime;
- circ->build_state->need_capacity = need_capacity;
- circ->build_state->is_internal = internal;
- circ->purpose = purpose;
- return circ;
- }
- /** Build a new circuit for <b>purpose</b>. If <b>info/b>
- * is defined, then use that as your exit router, else choose a suitable
- * exit node.
- *
- * Also launch a connection to the first OR in the chosen path, if
- * it's not open already.
- */
- circuit_t *
- circuit_establish_circuit(uint8_t purpose, extend_info_t *info,
- int need_uptime, int need_capacity, int internal)
- {
- circuit_t *circ;
- circ = circuit_init(purpose, need_uptime, need_capacity, internal);
- if (onion_pick_cpath_exit(circ, info) < 0 ||
- onion_populate_cpath(circ) < 0) {
- circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
- return NULL;
- }
- control_event_circuit_status(circ, CIRC_EVENT_LAUNCHED);
- if (circuit_handle_first_hop(circ) < 0) {
- circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
- return NULL;
- }
- return circ;
- }
- /** Start establishing the first hop of our circuit. Figure out what
- * OR we should connect to, and if necessary start the connection to
- * it. If we're already connected, then send the 'create' cell.
- * Return 0 for ok, -1 if circ should be marked-for-close. */
- int
- circuit_handle_first_hop(circuit_t *circ)
- {
- crypt_path_t *firsthop;
- connection_t *n_conn;
- char tmpbuf[INET_NTOA_BUF_LEN+1];
- struct in_addr in;
- firsthop = onion_next_hop_in_cpath(circ->cpath);
- tor_assert(firsthop);
- tor_assert(firsthop->extend_info);
- /* now see if we're already connected to the first OR in 'route' */
- in.s_addr = htonl(firsthop->extend_info->addr);
- tor_inet_ntoa(&in, tmpbuf, sizeof(tmpbuf));
- debug(LD_CIRC,"Looking for firsthop '%s:%u'",tmpbuf,
- firsthop->extend_info->port);
- /* imprint the circuit with its future n_conn->id */
- memcpy(circ->n_conn_id_digest, firsthop->extend_info->identity_digest,
- DIGEST_LEN);
- n_conn = connection_or_get_by_identity_digest(
- firsthop->extend_info->identity_digest);
- /* If we don't have an open conn, or the conn we have is obsolete
- * (i.e. old or broken) and the other side will let us make a second
- * connection without dropping it immediately... */
- if (!n_conn || n_conn->state != OR_CONN_STATE_OPEN ||
- (n_conn->is_obsolete &&
- router_digest_version_as_new_as(firsthop->extend_info->identity_digest,
- "0.1.1.9-alpha-cvs"))) {
- /* not currently connected */
- circ->n_addr = firsthop->extend_info->addr;
- circ->n_port = firsthop->extend_info->port;
- if (!n_conn || n_conn->is_obsolete) { /* launch the connection */
- n_conn = connection_or_connect(firsthop->extend_info->addr,
- firsthop->extend_info->port,
- firsthop->extend_info->identity_digest);
- if (!n_conn) { /* connect failed, forget the whole thing */
- info(LD_CIRC,"connect to firsthop failed. Closing.");
- return -1;
- }
- }
- debug(LD_CIRC,"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 0;
- } else { /* it's already open. use it. */
- circ->n_addr = n_conn->addr;
- circ->n_port = n_conn->port;
- circ->n_conn = n_conn;
- debug(LD_CIRC,"Conn open. Delivering first onion skin.");
- if (circuit_send_next_onion_skin(circ) < 0) {
- info(LD_CIRC,"circuit_send_next_onion_skin failed.");
- return -1;
- }
- }
- return 0;
- }
- /** Find any circuits that are waiting on <b>or_conn</b> to become
- * open and get them to send their create cells forward.
- *
- * Status is 1 if connect succeeded, or 0 if connect failed.
- */
- void
- circuit_n_conn_done(connection_t *or_conn, int status)
- {
- extern smartlist_t *circuits_pending_or_conns;
- debug(LD_CIRC,"or_conn to %s, status=%d",
- or_conn->nickname ? or_conn->nickname : "NULL", status);
- if (!circuits_pending_or_conns)
- return;
- SMARTLIST_FOREACH(circuits_pending_or_conns, circuit_t *, circ,
- {
- if (circ->marked_for_close)
- continue;
- tor_assert(circ->state == CIRCUIT_STATE_OR_WAIT);
- if (!circ->n_conn &&
- circ->n_addr == or_conn->addr &&
- circ->n_port == or_conn->port &&
- !memcmp(or_conn->identity_digest, circ->n_conn_id_digest,
- DIGEST_LEN)) {
- if (!status) { /* or_conn failed; close circ */
- info(LD_CIRC,"or_conn failed. Closing circ.");
- circuit_mark_for_close(circ, END_CIRC_REASON_OR_IDENTITY);
- continue;
- }
- debug(LD_CIRC,"Found circ %d, sending create cell.", circ->n_circ_id);
- /* circuit_deliver_create_cell will set n_circ_id and add us to
- * orconn_circuid_circuit_map, so we don't need to call
- * set_circid_orconn here. */
- circ->n_conn = or_conn;
- if (CIRCUIT_IS_ORIGIN(circ)) {
- if (circuit_send_next_onion_skin(circ) < 0) {
- info(LD_CIRC,
- "send_next_onion_skin failed; circuit marked for closing.");
- circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
- continue;
- /* XXX could this be bad, eg if next_onion_skin failed because conn
- * died? */
- }
- } else {
- /* pull the create cell out of circ->onionskin, and send it */
- tor_assert(circ->onionskin);
- if (circuit_deliver_create_cell(circ,CELL_CREATE,circ->onionskin)<0) {
- circuit_mark_for_close(circ, END_CIRC_REASON_RESOURCELIMIT);
- continue;
- }
- tor_free(circ->onionskin);
- circuit_set_state(circ, CIRCUIT_STATE_OPEN);
- }
- }
- });
- }
- /** Find a new circid that isn't currently in use on the circ->n_conn
- * for the outgoing
- * circuit <b>circ</b>, and deliver a cell of type <b>cell_type</b>
- * (either CELL_CREATE or CELL_CREATE_FAST) with payload <b>payload</b>
- * to this circuit.
- * Return -1 if we failed to find a suitable circid, else return 0.
- */
- static int
- circuit_deliver_create_cell(circuit_t *circ, uint8_t cell_type, char *payload)
- {
- cell_t cell;
- uint16_t id;
- tor_assert(circ);
- tor_assert(circ->n_conn);
- tor_assert(circ->n_conn->type == CONN_TYPE_OR);
- tor_assert(payload);
- tor_assert(cell_type == CELL_CREATE || cell_type == CELL_CREATE_FAST);
- id = get_unique_circ_id_by_conn(circ->n_conn);
- if (!id) {
- warn(LD_CIRC,"failed to get unique circID.");
- return -1;
- }
- debug(LD_CIRC,"Chosen circID %u.", id);
- circuit_set_circid_orconn(circ, id, circ->n_conn, N_CONN_CHANGED);
- memset(&cell, 0, sizeof(cell_t));
- cell.command = cell_type;
- cell.circ_id = circ->n_circ_id;
- memcpy(cell.payload, payload, ONIONSKIN_CHALLENGE_LEN);
- connection_or_write_cell_to_buf(&cell, circ->n_conn);
- return 0;
- }
- /** We've decided to start our reachability testing. If all
- * is set, log this to the user. Return 1 if we did, or 0 if
- * we chose not to log anything. */
- int
- inform_testing_reachability(void)
- {
- char dirbuf[128];
- routerinfo_t *me = router_get_my_routerinfo();
- if (!me)
- return 0;
- if (me->dir_port)
- tor_snprintf(dirbuf, sizeof(dirbuf), " and DirPort %s:%d",
- me->address, me->dir_port);
- log(LOG_NOTICE, LD_OR, "Now checking whether ORPort %s:%d%s %s reachable... "
- "(this may take up to %d minutes -- look for log "
- "messages indicating success)",
- me->address, me->or_port,
- me->dir_port ? dirbuf : "",
- me->dir_port ? "are" : "is",
- TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT/60);
- return 1;
- }
- /** Return true iff we should send a create_fast cell to build a circuit
- * starting at <b>router</b>. (If <b>router</b> is NULL, we don't have
- * information on the router. */
- static INLINE int
- should_use_create_fast_for_router(routerinfo_t *router)
- {
- or_options_t *options = get_options();
- if (!options->FastFirstHopPK || options->ORPort)
- return 0;
- else if (!router || !router->platform ||
- !tor_version_as_new_as(router->platform, "0.1.0.6-rc"))
- return 0;
- else
- return 1;
- }
- extern int has_completed_circuit;
- /** This is the backbone function for building circuits.
- *
- * If circ's first hop is closed, then we need to build a create
- * cell and send it forward.
- *
- * Otherwise, we need to build a relay extend cell and send it
- * forward.
- *
- * Return -reason if we want to tear down circ, else return 0.
- */
- int
- circuit_send_next_onion_skin(circuit_t *circ)
- {
- crypt_path_t *hop;
- routerinfo_t *router;
- char payload[2+4+DIGEST_LEN+ONIONSKIN_CHALLENGE_LEN];
- char *onionskin;
- size_t payload_len;
- tor_assert(circ);
- tor_assert(CIRCUIT_IS_ORIGIN(circ));
- if (circ->cpath->state == CPATH_STATE_CLOSED) {
- int fast;
- uint8_t cell_type;
- debug(LD_CIRC,"First skin; sending create cell.");
- router = router_get_by_digest(circ->n_conn->identity_digest);
- fast = should_use_create_fast_for_router(router);
- if (! fast) {
- /* We are an OR, or we are connecting to an old Tor: we should
- * send an old slow create cell.
- */
- cell_type = CELL_CREATE;
- if (onion_skin_create(circ->cpath->extend_info->onion_key,
- &(circ->cpath->dh_handshake_state),
- payload) < 0) {
- warn(LD_CIRC,"onion_skin_create (first hop) failed.");
- return - END_CIRC_REASON_INTERNAL;
- }
- } else {
- /* We are not an OR, and we're building the first hop of a circuit to a
- * new OR: we can be speedy and use CREATE_FAST to save an RSA operation
- * and a DH operation. */
- cell_type = CELL_CREATE_FAST;
- memset(payload, 0, sizeof(payload));
- crypto_rand(circ->cpath->fast_handshake_state,
- sizeof(circ->cpath->fast_handshake_state));
- memcpy(payload, circ->cpath->fast_handshake_state,
- sizeof(circ->cpath->fast_handshake_state));
- }
- if (circuit_deliver_create_cell(circ, cell_type, payload) < 0)
- return - END_CIRC_REASON_RESOURCELIMIT;
- circ->cpath->state = CPATH_STATE_AWAITING_KEYS;
- circuit_set_state(circ, CIRCUIT_STATE_BUILDING);
- info(LD_CIRC,"First hop: finished sending %s cell to '%s'",
- fast ? "CREATE_FAST" : "CREATE",
- router ? router->nickname : "<unnamed>");
- } else {
- tor_assert(circ->cpath->state == CPATH_STATE_OPEN);
- tor_assert(circ->state == CIRCUIT_STATE_BUILDING);
- debug(LD_CIRC,"starting to send subsequent skin.");
- hop = onion_next_hop_in_cpath(circ->cpath);
- if (!hop) {
- /* done building the circuit. whew. */
- circuit_set_state(circ, CIRCUIT_STATE_OPEN);
- info(LD_CIRC,"circuit built!");
- circuit_reset_failure_count(0);
- if (!has_completed_circuit) {
- or_options_t *options = get_options();
- has_completed_circuit=1;
- /* FFFF Log a count of known routers here */
- log(LOG_NOTICE, LD_GENERAL,
- "Tor has successfully opened a circuit. Looks like it's working.");
- if (server_mode(options) && !check_whether_orport_reachable()) {
- inform_testing_reachability();
- consider_testing_reachability();
- }
- }
- circuit_rep_hist_note_result(circ);
- circuit_has_opened(circ); /* do other actions as necessary */
- return 0;
- }
- *(uint32_t*)payload = htonl(hop->extend_info->addr);
- *(uint16_t*)(payload+4) = htons(hop->extend_info->port);
- onionskin = payload+2+4;
- memcpy(payload+2+4+ONIONSKIN_CHALLENGE_LEN,
- hop->extend_info->identity_digest, DIGEST_LEN);
- payload_len = 2+4+ONIONSKIN_CHALLENGE_LEN+DIGEST_LEN;
- if (onion_skin_create(hop->extend_info->onion_key,
- &(hop->dh_handshake_state), onionskin) < 0) {
- warn(LD_CIRC,"onion_skin_create failed.");
- return - END_CIRC_REASON_INTERNAL;
- }
- debug(LD_CIRC,"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, payload_len, hop->prev) < 0)
- return 0; /* circuit is closed */
- hop->state = CPATH_STATE_AWAITING_KEYS;
- }
- return 0;
- }
- /** Our clock just jumped forward by <b>seconds_elapsed</b>. Assume
- * something has also gone wrong with our network: notify the user,
- * and abandon all not-yet-used circuits. */
- void
- circuit_note_clock_jumped(int seconds_elapsed)
- {
- log(LOG_NOTICE, LD_GENERAL,"Your clock just jumped %d seconds forward; "
- "assuming established circuits no longer work.", seconds_elapsed);
- has_completed_circuit=0; /* so it'll log when it works again */
- circuit_mark_all_unused_circs();
- circuit_expire_all_dirty_circs();
- }
- /** 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 using
- * a create cell. Return -1 if we want to warn and tear down the circuit,
- * else return 0.
- */
- int
- circuit_extend(cell_t *cell, circuit_t *circ)
- {
- connection_t *n_conn;
- relay_header_t rh;
- char *onionskin;
- char *id_digest=NULL;
- if (circ->n_conn) {
- log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,
- "n_conn already set. Bug/attack. Closing.");
- return -1;
- }
- relay_header_unpack(&rh, cell->payload);
- if (rh.length < 4+2+ONIONSKIN_CHALLENGE_LEN+DIGEST_LEN) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Wrong length %d on extend cell. Closing circuit.",
- rh.length);
- 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));
- onionskin = cell->payload+RELAY_HEADER_SIZE+4+2;
- id_digest = cell->payload+RELAY_HEADER_SIZE+4+2+ONIONSKIN_CHALLENGE_LEN;
- n_conn = connection_or_get_by_identity_digest(id_digest);
- /* If we don't have an open conn, or the conn we have is obsolete
- * (i.e. old or broken) and the other side will let us make a second
- * connection without dropping it immediately... */
- if (!n_conn || n_conn->state != OR_CONN_STATE_OPEN ||
- (n_conn->is_obsolete &&
- router_digest_version_as_new_as(id_digest,"0.1.1.9-alpha-cvs"))) {
- /* Note 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;
- char tmpbuf[INET_NTOA_BUF_LEN];
- in.s_addr = htonl(circ->n_addr);
- tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
- info(LD_CIRC|LD_OR,"Next router (%s:%d) not connected. Connecting.",
- tmpbuf, circ->n_port);
- circ->onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
- memcpy(circ->onionskin, onionskin, ONIONSKIN_CHALLENGE_LEN);
- circuit_set_state(circ, CIRCUIT_STATE_OR_WAIT);
- /* imprint the circuit with its future n_conn->id */
- memcpy(circ->n_conn_id_digest, id_digest, DIGEST_LEN);
- if (n_conn && !n_conn->is_obsolete) {
- circ->n_addr = n_conn->addr;
- circ->n_port = n_conn->port;
- } else {
- /* we should try to open a connection */
- n_conn = connection_or_connect(circ->n_addr, circ->n_port, id_digest);
- if (!n_conn) {
- info(LD_CIRC,"Launching n_conn failed. Closing circuit.");
- circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED);
- return 0;
- }
- debug(LD_CIRC,"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 0;
- }
- /* these may be different if the router connected to us from elsewhere */
- circ->n_addr = n_conn->addr;
- circ->n_port = n_conn->port;
- circ->n_conn = n_conn;
- memcpy(circ->n_conn_id_digest, n_conn->identity_digest, DIGEST_LEN);
- debug(LD_CIRC,"n_conn is %s:%u",n_conn->address,n_conn->port);
- if (circuit_deliver_create_cell(circ, CELL_CREATE, onionskin) < 0)
- return -1;
- 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);
- tor_assert(key_data);
- tor_assert(!(cpath->f_crypto || cpath->b_crypto ||
- cpath->f_digest || cpath->b_digest));
- 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);
- if (!(cpath->f_crypto =
- crypto_create_init_cipher(key_data+(2*DIGEST_LEN),1))) {
- warn(LD_BUG,"Bug: forward cipher initialization failed.");
- return -1;
- }
- if (!(cpath->b_crypto =
- crypto_create_init_cipher(key_data+(2*DIGEST_LEN)+CIPHER_KEY_LEN,0))) {
- warn(LD_BUG,"Bug: 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;
- }
- /** A created or extended cell came back to us on the circuit, and it included
- * <b>reply</b> as its body. (If <b>reply_type</b> is CELL_CREATED, the body
- * contains (the second DH key, plus KH). If <b>reply_type</b> is
- * CELL_CREATED_FAST, the body contains a secret y and a hash H(x|y).)
- *
- * Calculate the appropriate keys and digests, make sure KH is
- * correct, and initialize this hop of the cpath.
- *
- * Return - reason if we want to mark circ for close, else return 0.
- */
- int
- circuit_finish_handshake(circuit_t *circ, uint8_t reply_type, char *reply)
- {
- 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 {
- hop = onion_next_hop_in_cpath(circ->cpath);
- if (!hop) { /* got an extended when we're all done? */
- warn(LD_PROTOCOL,"got extended when circ already built? Closing.");
- return - END_CIRC_REASON_TORPROTOCOL;
- }
- }
- tor_assert(hop->state == CPATH_STATE_AWAITING_KEYS);
- if (reply_type == CELL_CREATED && hop->dh_handshake_state) {
- if (onion_skin_client_handshake(hop->dh_handshake_state, reply, keys,
- DIGEST_LEN*2+CIPHER_KEY_LEN*2) < 0) {
- warn(LD_CIRC,"onion_skin_client_handshake failed.");
- return -END_CIRC_REASON_TORPROTOCOL;
- }
- /* Remember hash of g^xy */
- memcpy(hop->handshake_digest, reply+DH_KEY_LEN, DIGEST_LEN);
- } else if (reply_type == CELL_CREATED_FAST && !hop->dh_handshake_state) {
- if (fast_client_handshake(hop->fast_handshake_state, reply, keys,
- DIGEST_LEN*2+CIPHER_KEY_LEN*2) < 0) {
- warn(LD_CIRC,"fast_client_handshake failed.");
- return -END_CIRC_REASON_TORPROTOCOL;
- }
- memcpy(hop->handshake_digest, reply+DIGEST_LEN, DIGEST_LEN);
- } else {
- warn(LD_PROTOCOL,"CREATED cell type did not match CREATE cell type.");
- return -END_CIRC_REASON_TORPROTOCOL;
- }
- if (hop->dh_handshake_state) {
- crypto_dh_free(hop->dh_handshake_state); /* don't need it anymore */
- hop->dh_handshake_state = NULL;
- }
- memset(hop->fast_handshake_state, 0, sizeof(hop->fast_handshake_state));
- if (circuit_init_cpath_crypto(hop, keys, 0)<0) {
- return -END_CIRC_REASON_TORPROTOCOL;
- }
- hop->state = CPATH_STATE_OPEN;
- info(LD_CIRC,"Finished building %scircuit hop:",
- (reply_type == CELL_CREATED_FAST) ? "fast " : "");
- circuit_log_path(LOG_INFO,LD_CIRC,circ);
- control_event_circuit_status(circ, CIRC_EVENT_EXTENDED);
- return 0;
- }
- /** We received a relay truncated cell on circ.
- *
- * 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: for circ to close, and return 0.
- */
- int
- circuit_truncated(circuit_t *circ, crypt_path_t *layer)
- {
- // crypt_path_t *victim;
- // connection_t *stream;
- tor_assert(circ);
- tor_assert(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, END_CIRC_AT_ORIGIN);
- return 0;
- #if 0
- while (layer->next != circ->cpath) {
- /* we need to clear out layer->next */
- victim = layer->next;
- debug(LD_CIRC, "Killing a layer of the cpath.");
- for (stream = circ->p_streams; stream; stream=stream->next_stream) {
- if (stream->cpath_layer == victim) {
- /* XXXX NM LD_CIRC? */
- info(LD_APP, "Marking stream %d for close.", stream->stream_id);
- /* no need to send 'end' relay cells,
- * because the other side's already dead
- */
- connection_mark_unattached_ap(stream, END_STREAM_REASON_DESTROY);
- }
- }
- layer->next = victim->next;
- circuit_free_cpath_node(victim);
- }
- info(LD_CIRC, "finished");
- return 0;
- #endif
- }
- /** Given a response payload and keys, initialize, then send a created
- * cell back.
- */
- int
- onionskin_answer(circuit_t *circ, uint8_t cell_type, char *payload, char *keys)
- {
- cell_t cell;
- crypt_path_t *tmp_cpath;
- tmp_cpath = tor_malloc_zero(sizeof(crypt_path_t));
- tmp_cpath->magic = CRYPT_PATH_MAGIC;
- memset(&cell, 0, sizeof(cell_t));
- cell.command = cell_type;
- cell.circ_id = circ->p_circ_id;
- circuit_set_state(circ, CIRCUIT_STATE_OPEN);
- memcpy(cell.payload, payload,
- cell_type == CELL_CREATED ? ONIONSKIN_REPLY_LEN : DIGEST_LEN*2);
- debug(LD_CIRC,"init digest forward 0x%.8x, backward 0x%.8x.",
- (unsigned int)*(uint32_t*)(keys), (unsigned int)*(uint32_t*)(keys+20));
- if (circuit_init_cpath_crypto(tmp_cpath, keys, 0)<0) {
- warn(LD_BUG,"Circuit initialization failed");
- tor_free(tmp_cpath);
- return -1;
- }
- circ->n_digest = tmp_cpath->f_digest;
- circ->n_crypto = tmp_cpath->f_crypto;
- circ->p_digest = tmp_cpath->b_digest;
- circ->p_crypto = tmp_cpath->b_crypto;
- tmp_cpath->magic = 0;
- tor_free(tmp_cpath);
- if (cell_type == CELL_CREATED)
- memcpy(circ->handshake_digest, cell.payload+DH_KEY_LEN, DIGEST_LEN);
- else
- memcpy(circ->handshake_digest, cell.payload+DIGEST_LEN, DIGEST_LEN);
- connection_or_write_cell_to_buf(&cell, circ->p_conn);
- debug(LD_CIRC,"Finished sending 'created' cell.");
- if (!is_local_IP(circ->p_conn->addr) &&
- tor_tls_is_server(circ->p_conn->tls)) {
- /* record that we could process create cells from a non-local conn
- * that we didn't initiate; presumably this means that create cells
- * can reach us too. */
- router_orport_found_reachable();
- }
- return 0;
- }
- /** Choose a length for a circuit of purpose <b>purpose</b>.
- * Default length is 3 + the number of endpoints that would give something
- * away. If the routerlist <b>routers</b> doesn't have enough routers
- * to handle the desired path length, return as large a path length as
- * is feasible, except if it's less than 2, in which case return -1.
- */
- static int
- new_route_len(double cw, uint8_t purpose, extend_info_t *exit,
- smartlist_t *routers)
- {
- int num_acceptable_routers;
- int routelen;
- tor_assert(cw >= 0.);
- tor_assert(cw < 1.);
- tor_assert(routers);
- #ifdef TOR_PERF
- routelen = 2;
- #else
- routelen = 3;
- if (exit &&
- purpose != CIRCUIT_PURPOSE_TESTING &&
- purpose != CIRCUIT_PURPOSE_S_ESTABLISH_INTRO)
- routelen++;
- #endif
- debug(LD_CIRC,"Chosen route length %d (%d routers available).",routelen,
- smartlist_len(routers));
- num_acceptable_routers = count_acceptable_routers(routers);
- if (num_acceptable_routers < 2) {
- info(LD_CIRC,
- "Not enough acceptable routers (%d). Discarding this circuit.",
- num_acceptable_routers);
- return -1;
- }
- if (num_acceptable_routers < routelen) {
- info(LD_CIRC,"Not enough routers: cutting routelen from %d to %d.",
- routelen, num_acceptable_routers);
- routelen = num_acceptable_routers;
- }
- return routelen;
- }
- /** Fetch the list of predicted ports, dup it into a smartlist of
- * uint16_t's, remove the ones that are already handled by an
- * existing circuit, and return it.
- */
- static smartlist_t *
- circuit_get_unhandled_ports(time_t now)
- {
- smartlist_t *source = rep_hist_get_predicted_ports(now);
- smartlist_t *dest = smartlist_create();
- uint16_t *tmp;
- int i;
- for (i = 0; i < smartlist_len(source); ++i) {
- tmp = tor_malloc(sizeof(uint16_t));
- memcpy(tmp, smartlist_get(source, i), sizeof(uint16_t));
- smartlist_add(dest, tmp);
- }
- circuit_remove_handled_ports(dest);
- return dest;
- }
- /** Return 1 if we already have circuits present or on the way for
- * all anticipated ports. Return 0 if we should make more.
- *
- * If we're returning 0, set need_uptime and need_capacity to
- * indicate any requirements that the unhandled ports have.
- */
- int
- circuit_all_predicted_ports_handled(time_t now, int *need_uptime,
- int *need_capacity)
- {
- int i, enough;
- uint16_t *port;
- smartlist_t *sl = circuit_get_unhandled_ports(now);
- smartlist_t *LongLivedServices = get_options()->LongLivedPorts;
- tor_assert(need_uptime);
- tor_assert(need_capacity);
- enough = (smartlist_len(sl) == 0);
- for (i = 0; i < smartlist_len(sl); ++i) {
- port = smartlist_get(sl, i);
- if (smartlist_string_num_isin(LongLivedServices, *port))
- *need_uptime = 1;
- tor_free(port);
- }
- smartlist_free(sl);
- return enough;
- }
- /** Return 1 if <b>router</b> can handle one or more of the ports in
- * <b>needed_ports</b>, else return 0.
- */
- static int
- router_handles_some_port(routerinfo_t *router, smartlist_t *needed_ports)
- {
- int i;
- uint16_t port;
- for (i = 0; i < smartlist_len(needed_ports); ++i) {
- addr_policy_result_t r;
- port = *(uint16_t *)smartlist_get(needed_ports, i);
- tor_assert(port);
- r = router_compare_addr_to_addr_policy(0, port, router->exit_policy);
- if (r != ADDR_POLICY_REJECTED && r != ADDR_POLICY_PROBABLY_REJECTED)
- return 1;
- }
- return 0;
- }
- /** How many circuits do we want simultaneously in-progress to handle
- * a given stream?
- */
- #define MIN_CIRCUITS_HANDLING_STREAM 2
- static int
- ap_stream_wants_exit_attention(connection_t *conn)
- {
- if (conn->type == CONN_TYPE_AP &&
- conn->state == AP_CONN_STATE_CIRCUIT_WAIT &&
- !conn->marked_for_close &&
- !connection_edge_is_rendezvous_stream(conn) &&
- !circuit_stream_is_being_handled(conn, 0, MIN_CIRCUITS_HANDLING_STREAM))
- return 1;
- return 0;
- }
- /** Return a pointer to a suitable router to be the exit node for the
- * general-purpose circuit we're about to build.
- *
- * Look through the connection array, and choose a router that maximizes
- * the number of pending streams that can exit from this router.
- *
- * Return NULL if we can't find any suitable routers.
- */
- static routerinfo_t *
- choose_good_exit_server_general(routerlist_t *dir, int need_uptime,
- int need_capacity)
- {
- int *n_supported;
- int i, j;
- int n_pending_connections = 0;
- connection_t **carray;
- int n_connections;
- int best_support = -1;
- int n_best_support=0;
- smartlist_t *sl, *preferredexits, *excludedexits;
- routerinfo_t *router;
- or_options_t *options = get_options();
- get_connection_array(&carray, &n_connections);
- /* Count how many connections are waiting for a circuit to be built.
- * We use this for log messages now, but in the future we may depend on it.
- */
- for (i = 0; i < n_connections; ++i) {
- if (ap_stream_wants_exit_attention(carray[i]))
- ++n_pending_connections;
- }
- // log_fn(LOG_DEBUG, "Choosing exit node; %d connections are pending",
- // n_pending_connections);
- /* Now we count, for each of the routers in the directory, how many
- * of the pending connections could possibly exit from that
- * router (n_supported[i]). (We can't be sure about cases where we
- * don't know the IP address of the pending connection.)
- */
- n_supported = tor_malloc(sizeof(int)*smartlist_len(dir->routers));
- for (i = 0; i < smartlist_len(dir->routers); ++i) {/* iterate over routers */
- router = smartlist_get(dir->routers, i);
- if (router_is_me(router)) {
- n_supported[i] = -1;
- // log_fn(LOG_DEBUG,"Skipping node %s -- it's me.", router->nickname);
- /* XXX there's probably a reverse predecessor attack here, but
- * it's slow. should we take this out? -RD
- */
- continue;
- }
- if (!router->is_running) {
- n_supported[i] = -1;
- // log_fn(LOG_DEBUG,
- // "Skipping node %s (index %d) -- directory says it's not running.",
- // router->nickname, i);
- continue; /* skip routers that are known to be down */
- }
- if (router_is_unreliable(router, need_uptime, need_capacity)) {
- n_supported[i] = -1;
- continue; /* skip routers that are not suitable */
- }
- if (!router->is_verified &&
- (!(options->_AllowUnverified & ALLOW_UNVERIFIED_EXIT) ||
- router_is_unreliable(router, 1, 1))) {
- /* if it's unverified, and either we don't want it or it's unsuitable */
- n_supported[i] = -1;
- // log_fn(LOG_DEBUG,"Skipping node %s (index %d) -- unverified router.",
- // router->nickname, i);
- continue; /* skip unverified routers */
- }
- if (router_exit_policy_rejects_all(router)) {
- n_supported[i] = -1;
- // log_fn(LOG_DEBUG,"Skipping node %s (index %d) -- it rejects all.",
- // router->nickname, i);
- continue; /* skip routers that reject all */
- }
- n_supported[i] = 0;
- for (j = 0; j < n_connections; ++j) { /* iterate over connections */
- if (!ap_stream_wants_exit_attention(carray[j]))
- continue; /* Skip everything but APs in CIRCUIT_WAIT */
- if (connection_ap_can_use_exit(carray[j], router)) {
- ++n_supported[i];
- // log_fn(LOG_DEBUG,"%s is supported. n_supported[%d] now %d.",
- // router->nickname, i, n_supported[i]);
- } else {
- // log_fn(LOG_DEBUG,"%s (index %d) would reject this stream.",
- // router->nickname, i);
- }
- } /* End looping over connections. */
- if (n_supported[i] > best_support) {
- /* If this router is better than previous ones, remember its index
- * and goodness, and start counting how many routers are this good. */
- best_support = n_supported[i]; n_best_support=1;
- // log_fn(LOG_DEBUG,"%s is new best supported option so far.",
- // router->nickname);
- } else if (n_supported[i] == best_support) {
- /* If this router is _as good_ as the best one, just increment the
- * count of equally good routers.*/
- ++n_best_support;
- }
- }
- info(LD_CIRC,
- "Found %d servers that might support %d/%d pending connections.",
- n_best_support, best_support >= 0 ? best_support : 0,
- n_pending_connections);
- preferredexits = smartlist_create();
- add_nickname_list_to_smartlist(preferredexits,options->ExitNodes,1,1,1);
- excludedexits = smartlist_create();
- add_nickname_list_to_smartlist(excludedexits,options->ExcludeNodes,0,0,1);
- sl = smartlist_create();
- /* If any routers definitely support any pending connections, choose one
- * at random. */
- if (best_support > 0) {
- for (i = 0; i < smartlist_len(dir->routers); i++)
- if (n_supported[i] == best_support)
- smartlist_add(sl, smartlist_get(dir->routers, i));
- smartlist_subtract(sl,excludedexits);
- if (options->StrictExitNodes || smartlist_overlap(sl,preferredexits))
- smartlist_intersect(sl,preferredexits);
- router = routerlist_sl_choose_by_bandwidth(sl);
- } else {
- /* Either there are no pending connections, or no routers even seem to
- * possibly support any of them. Choose a router at random that satisfies
- * at least one predicted exit port. */
- int try;
- smartlist_t *needed_ports = circuit_get_unhandled_ports(time(NULL));
- if (best_support == -1) {
- if (need_uptime || need_capacity) {
- info(LD_CIRC, "We couldn't find any live%s%s routers; falling back "
- "to list of all routers.",
- need_capacity?", fast":"",
- need_uptime?", stable":"");
- return choose_good_exit_server_general(dir, 0, 0);
- }
- notice(LD_CIRC, "All routers are down or middleman -- choosing a "
- "doomed exit at random.");
- }
- for (try = 0; try < 2; try++) {
- /* try once to pick only from routers that satisfy a needed port,
- * then if there are none, pick from any that support exiting. */
- for (i = 0; i < smartlist_len(dir->routers); i++) {
- router = smartlist_get(dir->routers, i);
- if (n_supported[i] != -1 &&
- (try || router_handles_some_port(router, needed_ports))) {
- // log_fn(LOG_DEBUG,"Try %d: '%s' is a possibility.",
- // try, router->nickname);
- smartlist_add(sl, router);
- }
- }
- smartlist_subtract(sl,excludedexits);
- if (options->StrictExitNodes || smartlist_overlap(sl,preferredexits))
- smartlist_intersect(sl,preferredexits);
- /* XXX sometimes the above results in null, when the requested
- * exit node is down. we should pick it anyway. */
- router = routerlist_sl_choose_by_bandwidth(sl);
- if (router)
- break;
- }
- SMARTLIST_FOREACH(needed_ports, uint16_t *, cp, tor_free(cp));
- smartlist_free(needed_ports);
- }
- smartlist_free(preferredexits);
- smartlist_free(excludedexits);
- smartlist_free(sl);
- tor_free(n_supported);
- if (router) {
- info(LD_CIRC, "Chose exit server '%s'", router->nickname);
- return router;
- }
- if (options->StrictExitNodes) {
- warn(LD_CIRC, "No exit routers seem to be running; can't choose an exit.");
- }
- return NULL;
- }
- /** Return a pointer to a suitable router to be the exit node for the
- * circuit of purpose <b>purpose</b> that we're about to build (or NULL
- * if no router is suitable).
- *
- * For general-purpose circuits, pass it off to
- * choose_good_exit_server_general()
- *
- * For client-side rendezvous circuits, choose a random node, weighted
- * toward the preferences in 'options'.
- */
- static routerinfo_t *
- choose_good_exit_server(uint8_t purpose, routerlist_t *dir,
- int need_uptime, int need_capacity, int is_internal)
- {
- or_options_t *options = get_options();
- switch (purpose) {
- case CIRCUIT_PURPOSE_C_GENERAL:
- if (is_internal) /* pick it like a middle hop */
- return router_choose_random_node(NULL, get_options()->ExcludeNodes,
- NULL, need_uptime, need_capacity,
- get_options()->_AllowUnverified & ALLOW_UNVERIFIED_MIDDLE, 0);
- else
- return choose_good_exit_server_general(dir,need_uptime,need_capacity);
- case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
- return router_choose_random_node(
- options->RendNodes, options->RendExcludeNodes,
- NULL, need_uptime, need_capacity,
- options->_AllowUnverified & ALLOW_UNVERIFIED_RENDEZVOUS, 0);
- }
- warn(LD_BUG,"Bug: unhandled purpose %d", purpose);
- tor_fragile_assert();
- return NULL;
- }
- /** Decide a suitable length for circ's cpath, and pick an exit
- * router (or use <b>exit</b> if provided). Store these in the
- * cpath. Return 0 if ok, -1 if circuit should be closed. */
- static int
- onion_pick_cpath_exit(circuit_t *circ, extend_info_t *exit)
- {
- cpath_build_state_t *state = circ->build_state;
- routerlist_t *rl = router_get_routerlist();
- int r;
- r = new_route_len(get_options()->PathlenCoinWeight, circ->purpose,
- exit, rl->routers);
- if (r < 1) /* must be at least 1 */
- return -1;
- state->desired_path_len = r;
- if (exit) { /* the circuit-builder pre-requested one */
- info(LD_CIRC,"Using requested exit node '%s'", exit->nickname);
- exit = extend_info_dup(exit);
- } else { /* we have to decide one */
- routerinfo_t *router =
- choose_good_exit_server(circ->purpose, rl, state->need_uptime,
- state->need_capacity, state->is_internal);
- if (!router) {
- warn(LD_CIRC,"failed to choose an exit server");
- return -1;
- }
- exit = extend_info_from_router(router);
- }
- state->chosen_exit = exit;
- return 0;
- }
- /** Give <b>circ</b> a new exit destination to <b>exit</b>, and add a
- * hop to the cpath reflecting this. Don't send the next extend cell --
- * the caller will do this if it wants to.
- */
- int
- circuit_append_new_exit(circuit_t *circ, extend_info_t *info)
- {
- cpath_build_state_t *state;
- tor_assert(info);
- tor_assert(circ && CIRCUIT_IS_ORIGIN(circ));
- state = circ->build_state;
- tor_assert(state);
- if (state->chosen_exit)
- extend_info_free(state->chosen_exit);
- state->chosen_exit = extend_info_dup(info);
- ++circ->build_state->desired_path_len;
- onion_append_hop(&circ->cpath, info);
- return 0;
- }
- /** Take an open <b>circ</b>, and add a new hop at the end, based on
- * <b>info</b>. Set its state back to CIRCUIT_STATE_BUILDING, and then
- * send the next extend cell to begin connecting to that hop.
- */
- int
- circuit_extend_to_new_exit(circuit_t *circ, extend_info_t *info)
- {
- tor_assert(CIRCUIT_IS_ORIGIN(circ));
- circuit_append_new_exit(circ, info);
- circuit_set_state(circ, CIRCUIT_STATE_BUILDING);
- if (circuit_send_next_onion_skin(circ)<0) {
- warn(LD_CIRC, "Couldn't extend circuit to new point '%s'.",
- info->nickname);
- circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
- return -1;
- }
- return 0;
- }
- /** Return the number of routers in <b>routers</b> that are currently up
- * and available for building circuits through.
- */
- static int
- count_acceptable_routers(smartlist_t *routers)
- {
- int i, n;
- int num=0;
- routerinfo_t *r;
- n = smartlist_len(routers);
- for (i=0;i<n;i++) {
- r = smartlist_get(routers, i);
- // log_fn(LOG_DEBUG,"Contemplating whether router %d (%s) is a new option.",
- // i, r->nickname);
- if (r->is_running == 0) {
- // log_fn(LOG_DEBUG,"Nope, the directory says %d is not running.",i);
- goto next_i_loop;
- }
- if (r->is_verified == 0) {
- // log_fn(LOG_DEBUG,"Nope, the directory says %d is not verified.",i);
- /* XXXX009 But unverified routers *are* sometimes acceptable. */
- goto next_i_loop;
- }
- num++;
- // log_fn(LOG_DEBUG,"I like %d. num_acceptable_routers now %d.",i, num);
- next_i_loop:
- ; /* C requires an explicit statement after the label */
- }
- return num;
- }
- /** Add <b>new_hop</b> to the end of the doubly-linked-list <b>head_ptr</b>.
- * This function is used to extend cpath by another hop.
- */
- void
- onion_append_to_cpath(crypt_path_t **head_ptr, crypt_path_t *new_hop)
- {
- if (*head_ptr) {
- new_hop->next = (*head_ptr);
- new_hop->prev = (*head_ptr)->prev;
- (*head_ptr)->prev->next = new_hop;
- (*head_ptr)->prev = new_hop;
- } else {
- *head_ptr = new_hop;
- new_hop->prev = new_hop->next = new_hop;
- }
- }
- /** A helper function used by onion_extend_cpath(). Use <b>purpose</b>
- * and <b>state</b> and the cpath <b>head</b> (currently populated only
- * to length <b>cur_len</b> to decide a suitable middle hop for a
- * circuit. In particular, make sure we don't pick the exit node or its
- * family, and make sure we don't duplicate any previous nodes or their
- * families. */
- static routerinfo_t *
- choose_good_middle_server(uint8_t purpose,
- cpath_build_state_t *state,
- crypt_path_t *head,
- int cur_len)
- {
- int i;
- routerinfo_t *r, *choice;
- crypt_path_t *cpath;
- smartlist_t *excluded;
- tor_assert(_CIRCUIT_PURPOSE_MIN <= purpose &&
- purpose <= _CIRCUIT_PURPOSE_MAX);
- debug(LD_CIRC, "Contemplating intermediate hop: random choice.");
- excluded = smartlist_create();
- if ((r = build_state_get_exit_router(state))) {
- smartlist_add(excluded, r);
- routerlist_add_family(excluded, r);
- }
- if ((r = routerlist_find_my_routerinfo())) {
- smartlist_add(excluded, r);
- routerlist_add_family(excluded, r);
- }
- for (i = 0, cpath = head; i < cur_len; ++i, cpath=cpath->next) {
- if ((r = router_get_by_digest(cpath->extend_info->identity_digest))) {
- smartlist_add(excluded, r);
- routerlist_add_family(excluded, r);
- }
- }
- choice = router_choose_random_node(
- NULL, get_options()->ExcludeNodes, excluded,
- state->need_uptime, state->need_capacity,
- get_options()->_AllowUnverified & ALLOW_UNVERIFIED_MIDDLE, 0);
- smartlist_free(excluded);
- return choice;
- }
- /** Pick a good entry server for the circuit to be built according to
- * <b>state</b>. Don't reuse a chosen exit (if any), don't use this
- * router (if we're an OR), and respect firewall settings; if we're
- * using entry_guards, return one.
- *
- * If <b>state</b> is NULL, we're choosing routers to serve as entry
- * nodes, not for any particular circuit.
- */
- static routerinfo_t *
- choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state)
- {
- routerinfo_t *r, *choice;
- smartlist_t *excluded;
- or_options_t *options = get_options();
- if (state && options->UseEntryGuards) {
- return choose_random_entry(state);
- }
- excluded = smartlist_create();
- if (state && (r = build_state_get_exit_router(state))) {
- smartlist_add(excluded, r);
- routerlist_add_family(excluded, r);
- }
- if ((r = routerlist_find_my_routerinfo())) {
- smartlist_add(excluded, r);
- routerlist_add_family(excluded, r);
- }
- if (firewall_is_fascist()) {
- /* exclude all ORs that listen on the wrong port */
- routerlist_t *rl = router_get_routerlist();
- int i;
- for (i=0; i < smartlist_len(rl->routers); i++) {
- r = smartlist_get(rl->routers, i);
- if (!fascist_firewall_allows_address(r->addr,r->or_port))
- smartlist_add(excluded, r);
- }
- }
- // XXX we should exclude busy exit nodes here, too,
- // but only if there are enough other nodes available.
- choice = router_choose_random_node(
- NULL, options->ExcludeNodes,
- excluded, state ? state->need_uptime : 1,
- state ? state->need_capacity : 1,
- options->_AllowUnverified & ALLOW_UNVERIFIED_ENTRY, 0);
- smartlist_free(excluded);
- return choice;
- }
- /** Return the first non-open hop in cpath, or return NULL if all
- * hops are open. */
- static crypt_path_t *
- onion_next_hop_in_cpath(crypt_path_t *cpath)
- {
- crypt_path_t *hop = cpath;
- do {
- if (hop->state != CPATH_STATE_OPEN)
- return hop;
- hop = hop->next;
- } while (hop != cpath);
- return NULL;
- }
- /** Choose a suitable next hop in the cpath <b>head_ptr</b>,
- * based on <b>state</b>. Append the hop info to head_ptr.
- */
- static int
- onion_extend_cpath(uint8_t purpose, crypt_path_t **head_ptr,
- cpath_build_state_t *state)
- {
- int cur_len;
- crypt_path_t *cpath;
- extend_info_t *info = NULL;
- tor_assert(head_ptr);
- if (!*head_ptr) {
- cur_len = 0;
- } else {
- cur_len = 1;
- for (cpath = *head_ptr; cpath->next != *head_ptr; cpath = cpath->next) {
- ++cur_len;
- }
- }
- if (cur_len >= state->desired_path_len) {
- debug(LD_CIRC, "Path is complete: %d steps long",
- state->desired_path_len);
- return 1;
- }
- debug(LD_CIRC, "Path is %d long; we want %d", cur_len,
- state->desired_path_len);
- if (cur_len == state->desired_path_len - 1) { /* Picking last node */
- info = extend_info_dup(state->chosen_exit);
- } else if (cur_len == 0) { /* picking first node */
- routerinfo_t *r = choose_good_entry_server(purpose, state);
- if (r)
- info = extend_info_from_router(r);
- } else {
- routerinfo_t *r =
- choose_good_middle_server(purpose, state, *head_ptr, cur_len);
- if (r)
- info = extend_info_from_router(r);
- }
- if (!info) {
- warn(LD_CIRC,"Failed to find node for hop %d of our path. Discarding "
- "this circuit.", cur_len);
- return -1;
- }
- debug(LD_CIRC,"Chose router %s for hop %d (exit is %s)",
- info->nickname, cur_len+1, build_state_get_exit_nickname(state));
- onion_append_hop(head_ptr, info);
- extend_info_free(info);
- return 0;
- }
- /** Create a new hop, annotate it with information about its
- * corresponding router <b>choice</b>, and append it to the
- * end of the cpath <b>head_ptr</b>. */
- static int
- onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice)
- {
- crypt_path_t *hop = tor_malloc_zero(sizeof(crypt_path_t));
- /* link hop into the cpath, at the end. */
- onion_append_to_cpath(head_ptr, hop);
- hop->magic = CRYPT_PATH_MAGIC;
- hop->state = CPATH_STATE_CLOSED;
- hop->extend_info = extend_info_dup(choice);
- hop->package_window = CIRCWINDOW_START;
- hop->deliver_window = CIRCWINDOW_START;
- return 0;
- }
- /** Allocate and return a new extend_info_t that can be used to build a
- * circuit to or through the router <b>r</b>. */
- extend_info_t *
- extend_info_from_router(routerinfo_t *r)
- {
- extend_info_t *info;
- tor_assert(r);
- info = tor_malloc_zero(sizeof(extend_info_t));
- strlcpy(info->nickname, r->nickname, sizeof(info->nickname));
- memcpy(info->identity_digest, r->cache_info.identity_digest, DIGEST_LEN);
- info->onion_key = crypto_pk_dup_key(r->onion_pkey);
- info->addr = r->addr;
- info->port = r->or_port;
- return info;
- }
- /** Release storage held by an extend_info_t struct. */
- void
- extend_info_free(extend_info_t *info)
- {
- tor_assert(info);
- crypto_free_pk_env(info->onion_key);
- tor_free(info);
- }
- /** Allocate and return a new extend_info_t with the same contents as
- * <b>info</b>. */
- extend_info_t *
- extend_info_dup(extend_info_t *info)
- {
- extend_info_t *newinfo;
- tor_assert(info);
- newinfo = tor_malloc(sizeof(extend_info_t));
- memcpy(newinfo, info, sizeof(extend_info_t));
- newinfo->onion_key = crypto_pk_dup_key(info->onion_key);
- return newinfo;
- }
- /** Return the routerinfo_t for the chosen exit router in <b>state</b>.
- * If there is no chosen exit, or if we don't know the routerinfo_t for
- * the chosen exit, return NULL.
- */
- routerinfo_t *
- build_state_get_exit_router(cpath_build_state_t *state)
- {
- if (!state || !state->chosen_exit)
- return NULL;
- return router_get_by_digest(state->chosen_exit->identity_digest);
- }
- /** Return the nickname for the chosen exit router in <b>state</b>. If
- * there is no chosen exit, or if we don't know the routerinfo_t for the
- * chosen exit, return NULL.
- */
- const char *
- build_state_get_exit_nickname(cpath_build_state_t *state)
- {
- if (!state || !state->chosen_exit)
- return NULL;
- return state->chosen_exit->nickname;
- }
- /** Return the router corresponding to <b>e</b>, if <b>e</b> is
- * working well enough that we are willing to use it as an entry
- * right now. (Else return NULL.) In particular, it must be
- * - Listed as either up or never yet contacted;
- * - Present in the routerlist;
- * - Listed as 'stable' or 'fast' by the current dirserver concensus,
- * if demanded by <b>need_uptime</b> or <b>need_capacity</b>; and
- * - Allowed by our current ReachableAddresses config option.
- */
- static INLINE routerinfo_t *
- entry_is_live(entry_guard_t *e, int need_uptime, int need_capacity)
- {
- routerinfo_t *r;
- if (e->down_since && e->made_contact)
- return NULL;
- r = router_get_by_digest(e->identity);
- if (!r)
- return NULL;
- if (router_is_unreliable(r, need_uptime, need_capacity))
- return NULL;
- if (firewall_is_fascist() &&
- !fascist_firewall_allows_address(r->addr,r->or_port))
- return NULL;
- return r;
- }
- /** Return the number of entry guards that we think are usable. */
- static int
- num_live_entry_guards(void)
- {
- int n = 0;
- if (! entry_guards)
- return 0;
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
- {
- if (entry_is_live(entry, 0, 1))
- ++n;
- });
- return n;
- }
- /** Return 1 if <b>digest</b> matches the identity of any node
- * in the entry_guards list. Else return 0. */
- static INLINE int
- is_an_entry_guard(char *digest)
- {
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
- if (!memcmp(digest, entry->identity, DIGEST_LEN))
- return 1;
- );
- return 0;
- }
- static void
- log_entry_guards(int severity)
- {
- smartlist_t *elements = smartlist_create();
- char buf[1024];
- char *s;
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
- {
- tor_snprintf(buf, sizeof(buf), "%s (%s%s%s)",
- e->nickname,
- e->down_since ? "down " : "up ",
- e->unlisted_since ? "unlisted " : "listed ",
- e->made_contact ? "made-contact" : "never-contacted");
- smartlist_add(elements, tor_strdup(buf));
- });
- s = smartlist_join_strings(elements, ",", 0, NULL);
- SMARTLIST_FOREACH(elements, char*, cp, tor_free(cp));
- smartlist_free(elements);
- log_fn(severity,LD_CIRC,"%s",s);
- tor_free(s);
- }
- #define NUM_ENTRY_PICK_TRIES 100
- /** Add a new (preferably stable and fast) entry to our
- * entry_guards list. Return a pointer to the router if we succeed,
- * or NULL if we can't find any more suitable entries.
- *
- * If <b>chosen</b> is defined, use that one, and if it's not
- * already in our entry_guards list, put it at the *beginning*.
- * Else, put the one we pick at the end of the list. */
- static routerinfo_t *
- add_an_entry_guard(routerinfo_t *chosen)
- {
- routerinfo_t *router;
- entry_guard_t *entry;
- int tries_left = NUM_ENTRY_PICK_TRIES;
- again:
- if (--tries_left <= 0) {
- warn(LD_CIRC, "Tried finding a new entry, but failed. Bad news. XXX.");
- return NULL;
- }
- if (chosen)
- router = chosen;
- else
- router = choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
- if (!router)
- return NULL;
- /* make sure it's not already an entry */
- if (is_an_entry_guard(router->cache_info.identity_digest)) {
- if (chosen)
- return NULL;
- goto again;
- }
- entry = tor_malloc_zero(sizeof(entry_guard_t));
- /* XXXX Downgrade this to info before release. NM */
- notice(LD_CIRC, "Chose '%s' as new entry guard.", router->nickname);
- strlcpy(entry->nickname, router->nickname, sizeof(entry->nickname));
- memcpy(entry->identity, router->cache_info.identity_digest, DIGEST_LEN);
- if (chosen)
- smartlist_insert(entry_guards, 0, entry);
- else
- smartlist_add(entry_guards, entry);
- log_entry_guards(LOG_INFO);
- return router;
- }
- /** If the use of entry guards is configured, choose more entry guards
- * until we have enough in the list. */
- static void
- pick_entry_guards(void)
- {
- or_options_t *options = get_options();
- int changed = 0;
- tor_assert(entry_guards);
- while (num_live_entry_guards() < options->NumEntryGuards) {
- if (!add_an_entry_guard(NULL))
- break;
- changed = 1;
- }
- if (changed)
- entry_guards_changed();
- }
- /** Release all storage held by the list of entry guards. */
- void
- entry_guards_free_all(void)
- {
- if (entry_guards) {
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, tor_free(e));
- smartlist_free(entry_guards);
- entry_guards = NULL;
- }
- }
- /* XXX These are 12 hours for now, but I'd like to make them 30 days */
- /** How long (in seconds) do we allow an entry guard to be nonfunctional
- * before we give up on it? */
- #define ENTRY_ALLOW_DOWNTIME (1*12*60*60)
- /** How long (in seconds) do we allow an entry guard to be unlisted in the
- * directory before we give up on it? */
- #define ENTRY_ALLOW_UNLISTED (1*12*60*60)
- /** Remove all entry guards that have been down or unlisted for so
- * long that we don't think they'll come up again. Return 1 if we
- * removed any, or 0 if we did nothing. */
- static int
- remove_dead_entries(void)
- {
- char dbuf[HEX_DIGEST_LEN+1];
- char tbuf[ISO_TIME_LEN+1];
- time_t now = time(NULL);
- int i;
- int changed = 0;
- for (i = 0; i < smartlist_len(entry_guards); ) {
- entry_guard_t *entry = smartlist_get(entry_guards, i);
- const char *why = NULL;
- time_t since = 0;
- if (entry->unlisted_since &&
- entry->unlisted_since + ENTRY_ALLOW_UNLISTED < now) {
- why = "unlisted";
- since = entry->unlisted_since;
- } else if (entry->down_since &&
- entry->down_since + ENTRY_ALLOW_DOWNTIME < now) {
- why = "down";
- since = entry->down_since;
- }
- if (why) {
- base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN);
- format_local_iso_time(tbuf, since);
- warn(LD_CIRC, "Entry guard '%s' (%s) has been %s since %s; removing.",
- entry->nickname, dbuf, why, tbuf);
- tor_free(entry);
- smartlist_del_keeporder(entry_guards, i);
- log_entry_guards(LOG_INFO);
- changed = 1;
- } else
- ++i;
- }
- return changed ? 1 : 0;
- }
- /** A new directory or router-status has arrived; update the down/listed
- * status of the entry guards.
- *
- * An entry is 'down' if the directory lists it as nonrunning.
- * An entry is 'unlisted' if the directory doesn't include it.
- */
- void
- entry_guards_set_status_from_directory(void)
- {
- /* Don't call this on startup; only on a fresh download. Otherwise we'll
- * think that things are unlisted. */
- routerlist_t *routers;
- time_t now;
- int changed = 0;
- int severity = LOG_NOTICE;
- if (! entry_guards)
- return;
- routers = router_get_routerlist();
- now = time(NULL);
- /*XXXX Most of these warns should be non-warns. */
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
- {
- routerinfo_t *r = router_get_by_digest(entry->identity);
- if (! r) {
- if (! entry->unlisted_since) {
- entry->unlisted_since = time(NULL);
- changed = 1;
- warn(LD_CIRC,"Entry guard '%s' is not listed by directories.",
- entry->nickname);
- severity = LOG_WARN;
- }
- } else {
- if (entry->unlisted_since) {
- warn(LD_CIRC,"Entry guard '%s' is listed again by directories.",
- entry->nickname);
- changed = 1;
- severity = LOG_WARN;
- }
- entry->unlisted_since = 0;
- if (! r->is_running) {
- if (! entry->down_since) {
- entry->down_since = now;
- warn(LD_CIRC, "Entry guard '%s' is now down.", entry->nickname);
- changed = 1;
- severity = LOG_WARN;
- }
- } else {
- if (entry->down_since) {
- notice(LD_CIRC,"Entry guard '%s' is up in latest directories.",
- entry->nickname);
- changed = 1;
- }
- entry->down_since = 0;
- }
- }
- info(LD_CIRC, "Summary: Entry '%s' is %s, %s, and %s.",
- entry->nickname,
- entry->down_since ? "down" : "up",
- entry->unlisted_since ? "unlisted" : "listed",
- entry_is_live(entry, 0, 1) ? "live" : "not live");
- });
- if (remove_dead_entries())
- changed = 1;
- if (changed) {
- log_fn(severity, LD_CIRC, " (%d/%d entry guards are usable/new)",
- num_live_entry_guards(), smartlist_len(entry_guards));
- log_entry_guards(LOG_INFO);
- entry_guards_changed();
- }
- }
- /** Called when a connection to an OR with the identity digest <b>digest</b>
- * is established (<b>succeeded</b>==1) or has failed (<b>succeeded</b>==0).
- * If the OR is an entry, change that entry's up/down status.
- * Return 0 normally, or -1 if we want to tear down the new connection.
- */
- int
- entry_guard_set_status(const char *digest, int succeeded)
- {
- int changed = 0;
- int refuse_conn = 0;
- if (! entry_guards)
- return 0;
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
- {
- if (!memcmp(entry->identity, digest, DIGEST_LEN)) {
- if (succeeded) {
- if (!entry->made_contact) {
- /* We've just added a new long-term entry guard. Perhaps
- * the network just came back? We should give our earlier
- * entries another try too, and close this connection so
- * we don't use it before we've given the others a shot. */
- entry->made_contact = 1;
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
- {
- routerinfo_t *r;
- if (e->made_contact) {
- e->down_since = 0;
- r = entry_is_live(e, 0, 1);
- if (r) {
- refuse_conn = 1;
- r->is_running = 1;
- }
- }
- if (e == entry)
- break;
- });
- notice(LD_CIRC,
- "Connected to new entry guard '%s'. Marking earlier "
- "entry guards up. %d/%d entry guards usable/new.",
- entry->nickname,
- num_live_entry_guards(), smartlist_len(entry_guards));
- log_entry_guards(LOG_INFO);
- changed = 1;
- }
- if (entry->down_since) {
- entry->down_since = 0;
- /*XXXX shouldn't be so loud. NM */
- notice(LD_CIRC,
- "Connection to formerly down entry guard '%s' succeeded. "
- "%d/%d entry guards usable/new.", entry->nickname,
- num_live_entry_guards(), smartlist_len(entry_guards));
- log_entry_guards(LOG_INFO);
- changed = 1;
- }
- } else {
- if (!entry->made_contact) { /* dump him */
- notice(LD_CIRC,
- "Connection to never-contacted entry guard '%s' failed. "
- "Removing from the list. %d/%d entry guards usable/new.",
- entry->nickname,
- num_live_entry_guards()-1, smartlist_len(entry_guards)-1);
- tor_free(entry);
- smartlist_del_keeporder(entry_guards, entry_sl_idx);
- log_entry_guards(LOG_INFO);
- changed = 1;
- } else if (!entry->down_since) {
- entry->down_since = time(NULL);
- warn(LD_CIRC, "Connection to entry guard '%s' failed."
- " %d/%d entry guards usable/new.",
- entry->nickname,
- num_live_entry_guards(), smartlist_len(entry_guards));
- log_entry_guards(LOG_INFO);
- changed = 1;
- }
- }
- }
- });
- if (changed)
- entry_guards_changed();
- return refuse_conn ? -1 : 0;
- }
- /** When we try to choose an entry guard, should we parse and add
- * config's EntryNodes first? */
- static int should_add_entry_nodes = 0;
- void
- entry_nodes_should_be_added(void)
- {
- info(LD_CIRC, "New EntryNodes config option detected. Will use.");
- should_add_entry_nodes = 1;
- }
- void
- entry_guards_prepend_from_config(void)
- {
- int missed_some = 0;
- int idx;
- or_options_t *options = get_options();
- smartlist_t *routers = smartlist_create();
- smartlist_t *tmp = smartlist_create();
- tor_assert(entry_guards);
- tor_assert(options->EntryNodes);
- if (options->StrictEntryNodes) {
- info(LD_CIRC,"Clearing old entry guards");
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, tor_free(e));
- smartlist_clear(entry_guards);
- entry_guards_changed();
- }
- add_nickname_list_to_smartlist(routers, options->EntryNodes,
- 0, 1, 1);
- /* take a moment first to notice whether we got them all */
- info(LD_CIRC,"Adding configured EntryNodes '%s'.",
- options->EntryNodes);
- smartlist_split_string(tmp, options->EntryNodes, ",",
- SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
- missed_some = smartlist_len(routers) != smartlist_len(tmp);
- SMARTLIST_FOREACH(tmp, char *, nick, tor_free(nick));
- smartlist_free(tmp);
- for (idx = smartlist_len(routers)-1 ; idx >= 0; idx--) {
- /* pick off the last one, turn it into a router, prepend it
- * to our entry_guards list. If we can't find it, set missed_some
- * to 1. */
- routerinfo_t *r = smartlist_get(routers, idx);
- add_an_entry_guard(r);
- }
- if (!missed_some)
- should_add_entry_nodes = 0; /* whew, we're done */
- smartlist_free(routers);
- }
- /** Pick a live (up and listed) entry guard from entry_guards, and
- * make sure not to pick this circuit's exit. */
- static routerinfo_t *
- choose_random_entry(cpath_build_state_t *state)
- {
- or_options_t *options = get_options();
- smartlist_t *live_entry_guards = smartlist_create();
- routerinfo_t *chosen_exit = build_state_get_exit_router(state);
- routerinfo_t *r = NULL;
- int need_uptime = state->need_uptime;
- int need_capacity = state->need_capacity;
- if (!entry_guards)
- entry_guards = smartlist_create();
- if (should_add_entry_nodes)
- entry_guards_prepend_from_config();
- if (!options->StrictEntryNodes &&
- (! entry_guards ||
- smartlist_len(entry_guards) < options->NumEntryGuards))
- pick_entry_guards();
- retry:
- smartlist_clear(live_entry_guards);
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
- {
- r = entry_is_live(entry, need_uptime, need_capacity);
- if (r && r != chosen_exit) {
- smartlist_add(live_entry_guards, r);
- if (smartlist_len(live_entry_guards) >= options->NumEntryGuards)
- break; /* we have enough */
- }
- });
- /* Try to have at least 2 choices available. This way we don't
- * get stuck with a single live-but-crummy entry and just keep
- * using him.
- * (We might get 2 live-but-crummy entry guards, but so be it.) */
- if (smartlist_len(live_entry_guards) < 2) {
- if (need_uptime) {
- need_uptime = 0; /* try without that requirement */
- goto retry;
- }
- if (!options->StrictEntryNodes) {
- /* still no? try adding a new entry then */
- r = add_an_entry_guard(NULL);
- if (r) {
- smartlist_add(live_entry_guards, r);
- entry_guards_changed();
- }
- }
- if (!r && need_capacity) {
- /* still no? last attempt, try without requiring capacity */
- need_capacity = 0;
- goto retry;
- }
- /* live_entry_guards will be empty below. Oh well, we tried. */
- }
- r = smartlist_choose(live_entry_guards);
- smartlist_free(live_entry_guards);
- return r;
- }
- /** Parse <b>state</b> and learn about the entry guards it describes.
- * If <b>set</b> is true, and there are no errors, replace the global
- * entry_list with what we find.
- * On success, return 0. On failure, set *<b>err</b> to a string
- * describing the error, and return -1.
- */
- int
- entry_guards_parse_state(or_state_t *state, int set, const char **err)
- {
- entry_guard_t *node = NULL;
- smartlist_t *new_entry_guards = smartlist_create();
- config_line_t *line;
- *err = NULL;
- for (line = state->EntryGuards; line; line = line->next) {
- if (!strcasecmp(line->key, "EntryGuard")) {
- smartlist_t *args = smartlist_create();
- node = tor_malloc_zero(sizeof(entry_guard_t));
- /* all entry guards on disk have been contacted */
- node->made_contact = 1;
- smartlist_add(new_entry_guards, node);
- smartlist_split_string(args, line->value, " ",
- SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
- if (smartlist_len(args)<2) {
- *err = "Too few arguments to EntryGuard";
- } else if (!is_legal_nickname(smartlist_get(args,0))) {
- *err = "Bad nickname for EntryGuard";
- } else {
- strlcpy(node->nickname, smartlist_get(args,0), MAX_NICKNAME_LEN+1);
- if (base16_decode(node->identity, DIGEST_LEN, smartlist_get(args,1),
- strlen(smartlist_get(args,1)))<0) {
- *err = "Bad hex digest for EntryGuard";
- }
- }
- SMARTLIST_FOREACH(args, char*, cp, tor_free(cp));
- smartlist_free(args);
- if (*err)
- break;
- } else {
- time_t when;
- if (!node) {
- *err = "EntryGuardDownSince/UnlistedSince without EntryGuard";
- break;
- }
- if (parse_iso_time(line->value, &when)<0) {
- *err = "Bad time in EntryGuardDownSince/UnlistedSince";
- break;
- }
- if (!strcasecmp(line->key, "EntryGuardDownSince"))
- node->down_since = when;
- else
- node->unlisted_since = when;
- }
- }
- if (*err || !set) {
- SMARTLIST_FOREACH(new_entry_guards, entry_guard_t *, e, tor_free(e));
- smartlist_free(new_entry_guards);
- } else { /* !*err && set */
- if (entry_guards) {
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, tor_free(e));
- smartlist_free(entry_guards);
- }
- entry_guards = new_entry_guards;
- entry_guards_dirty = 0;
- }
- return *err ? -1 : 0;
- }
- /** Our list of entry guards has changed, or some element of one
- * of our entry guards has changed. Write the changes to disk. */
- static void
- entry_guards_changed(void)
- {
- entry_guards_dirty = 1;
- or_state_save();
- }
- /** If the entry guard info has not changed, do nothing and return.
- * Otherwise, free the EntryGuards piece of <b>state</b> and create
- * a new one out of the global entry_guards list, and then mark
- * <b>state</b> dirty so it will get saved to disk.
- */
- void
- entry_guards_update_state(or_state_t *state)
- {
- config_line_t **next, *line;
- if (! entry_guards_dirty)
- return;
- config_free_lines(state->EntryGuards);
- next = &state->EntryGuards;
- *next = NULL;
- if (!entry_guards)
- entry_guards = smartlist_create();
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
- {
- char dbuf[HEX_DIGEST_LEN+1];
- if (!e->made_contact)
- continue; /* don't write this one to disk */
- *next = line = tor_malloc_zero(sizeof(config_line_t));
- line->key = tor_strdup("EntryGuard");
- line->value = tor_malloc(HEX_DIGEST_LEN+MAX_NICKNAME_LEN+2);
- base16_encode(dbuf, sizeof(dbuf), e->identity, DIGEST_LEN);
- tor_snprintf(line->value,HEX_DIGEST_LEN+MAX_NICKNAME_LEN+2,
- "%s %s", e->nickname, dbuf);
- next = &(line->next);
- if (e->down_since) {
- *next = line = tor_malloc_zero(sizeof(config_line_t));
- line->key = tor_strdup("EntryGuardDownSince");
- line->value = tor_malloc(ISO_TIME_LEN+1);
- format_iso_time(line->value, e->down_since);
- next = &(line->next);
- }
- if (e->unlisted_since) {
- *next = line = tor_malloc_zero(sizeof(config_line_t));
- line->key = tor_strdup("EntryGuardUnlistedSince");
- line->value = tor_malloc(ISO_TIME_LEN+1);
- format_iso_time(line->value, e->unlisted_since);
- next = &(line->next);
- }
- });
- state->dirty = 1;
- entry_guards_dirty = 0;
- }
- /** If <b>question</b> is the string "entry-guards", then dump
- * to *<b>answer</b> a newly allocated string describing all of
- * the nodes in the global entry_guards list. See control-spec.txt
- * for details.
- * For backward compatibility, we also handle the string "helper-nodes".
- * */
- int
- entry_guards_getinfo(const char *question, char **answer)
- {
- if (!strcmp(question,"entry-guards") ||
- !strcmp(question,"helper-nodes")) {
- smartlist_t *sl = smartlist_create();
- char tbuf[ISO_TIME_LEN+1];
- char dbuf[HEX_DIGEST_LEN+1];
- if (!entry_guards)
- entry_guards = smartlist_create();
- SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
- {
- size_t len = HEX_DIGEST_LEN+ISO_TIME_LEN+32;
- char *c = tor_malloc(len);
- const char *status = NULL;
- time_t when = 0;
- if (!e->made_contact) {
- status = "never-connected";
- } else if (e->unlisted_since) {
- when = e->unlisted_since;
- status = "unlisted";
- } else if (e->down_since) {
- when = e->down_since;
- status = "down";
- } else {
- status = "up";
- }
- base16_encode(dbuf, sizeof(dbuf), e->identity, DIGEST_LEN);
- if (when) {
- format_iso_time(tbuf, when);
- tor_snprintf(c, len, "$%s %s %s\n", dbuf, status, tbuf);
- } else {
- tor_snprintf(c, len, "$%s %s\n", dbuf, status);
- }
- smartlist_add(sl, c);
- });
- *answer = smartlist_join_strings(sl, "", 0, NULL);
- SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
- smartlist_free(sl);
- }
- return 0;
- }
|