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- /* Copyright 2001 Matej Pfajfar, 2001-2004 Roger Dingledine. */
- /* See LICENSE for licensing information */
- /* $Id$ */
- /**
- * \file circuituse.c
- * \brief Launch the right sort of circuits, attach streams to them.
- **/
- #include "or.h"
- extern or_options_t options; /* command-line and config-file options */
- /********* START VARIABLES **********/
- extern circuit_t *global_circuitlist; /* from circuitlist.c */
- extern int has_fetched_directory; /* from main.c */
- /********* END VARIABLES ************/
- static void circuit_expire_old_circuits(void);
- static void circuit_increment_failure_count(void);
- /* Return 1 if <b>circ</b> could be returned by circuit_get_best().
- * Else return 0.
- */
- static int circuit_is_acceptable(circuit_t *circ,
- connection_t *conn,
- int must_be_open,
- uint8_t purpose,
- time_t now)
- {
- routerinfo_t *exitrouter;
- if (!CIRCUIT_IS_ORIGIN(circ))
- return 0; /* this circ doesn't start at us */
- if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn))
- return 0; /* ignore non-open circs */
- if (circ->marked_for_close)
- return 0;
- /* if this circ isn't our purpose, skip. */
- if(purpose == CIRCUIT_PURPOSE_C_REND_JOINED && !must_be_open) {
- if(circ->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND &&
- circ->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
- circ->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED &&
- circ->purpose != CIRCUIT_PURPOSE_C_REND_JOINED)
- return 0;
- } else if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT && !must_be_open) {
- if (circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCING &&
- circ->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT)
- return 0;
- } else {
- if(purpose != circ->purpose)
- return 0;
- }
- if(purpose == CIRCUIT_PURPOSE_C_GENERAL)
- if(circ->timestamp_dirty &&
- circ->timestamp_dirty+options.NewCircuitPeriod <= now)
- return 0;
- if(conn) {
- /* decide if this circ is suitable for this conn */
- /* for rend circs, circ->cpath->prev is not the last router in the
- * circuit, it's the magical extra bob hop. so just check the nickname
- * of the one we meant to finish at.
- */
- exitrouter = router_get_by_digest(circ->build_state->chosen_exit_digest);
- if(!exitrouter) {
- log_fn(LOG_INFO,"Skipping broken circ (exit router vanished)");
- return 0; /* this circuit is screwed and doesn't know it yet */
- }
- if (conn->socks_request &&
- conn->socks_request->command == SOCKS_COMMAND_RESOLVE) {
- /* 0.0.7 servers and earlier don't support DNS resolution. There are no
- * ORs running code before 0.0.7, so we only worry about 0.0.7. Once all
- * servers are running 0.0.8, remove this check. */
- if (!strncmp(exitrouter->platform, "Tor 0.0.7", 9))
- return 0;
- } else if(purpose == CIRCUIT_PURPOSE_C_GENERAL) {
- if(connection_ap_can_use_exit(conn, exitrouter) == ADDR_POLICY_REJECTED) {
- /* can't exit from this router */
- return 0;
- }
- } else { /* not general */
- if(rend_cmp_service_ids(conn->rend_query, circ->rend_query) &&
- (circ->rend_query[0] || purpose != CIRCUIT_PURPOSE_C_REND_JOINED)) {
- /* this circ is not for this conn, and it's not suitable
- * for cannibalizing either */
- return 0;
- }
- }
- }
- return 1;
- }
- /* Return 1 if circuit <b>a</b> is better than circuit <b>b</b> for
- * <b>purpose</b>, and return 0 otherwise. Used by circuit_get_best.
- */
- static int circuit_is_better(circuit_t *a, circuit_t *b, uint8_t purpose)
- {
- switch(purpose) {
- case CIRCUIT_PURPOSE_C_GENERAL:
- /* if it's used but less dirty it's best;
- * else if it's more recently created it's best
- */
- if(b->timestamp_dirty) {
- if(a->timestamp_dirty &&
- a->timestamp_dirty > b->timestamp_dirty)
- return 1;
- } else {
- if(a->timestamp_dirty ||
- a->timestamp_created > b->timestamp_created)
- return 1;
- }
- break;
- case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT:
- /* the closer it is to ack_wait the better it is */
- if(a->purpose > b->purpose)
- return 1;
- break;
- case CIRCUIT_PURPOSE_C_REND_JOINED:
- /* the closer it is to rend_joined the better it is */
- if(a->purpose > b->purpose)
- return 1;
- break;
- }
- return 0;
- }
- /** Find the best circ that conn can use, preferably one which is
- * dirty. Circ must not be too old.
- *
- * Conn must be defined.
- *
- * If must_be_open, ignore circs not in CIRCUIT_STATE_OPEN.
- *
- * circ_purpose specifies what sort of circuit we must have.
- * It can be C_GENERAL, C_INTRODUCE_ACK_WAIT, or C_REND_JOINED.
- *
- * If it's REND_JOINED and must_be_open==0, then return the closest
- * rendezvous-purposed circuit that you can find.
- *
- * If it's INTRODUCE_ACK_WAIT and must_be_open==0, then return the
- * closest introduce-purposed circuit that you can find.
- */
- static circuit_t *
- circuit_get_best(connection_t *conn, int must_be_open, uint8_t purpose)
- {
- circuit_t *circ, *best=NULL;
- time_t now = time(NULL);
- tor_assert(conn);
- tor_assert(purpose == CIRCUIT_PURPOSE_C_GENERAL ||
- purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT ||
- purpose == CIRCUIT_PURPOSE_C_REND_JOINED);
- for (circ=global_circuitlist;circ;circ = circ->next) {
- if (!circuit_is_acceptable(circ,conn,must_be_open,purpose,now))
- continue;
- /* now this is an acceptable circ to hand back. but that doesn't
- * mean it's the *best* circ to hand back. try to decide.
- */
- if(!best || circuit_is_better(circ,best,purpose))
- best = circ;
- }
- return best;
- }
- /** Circuits that were born at the end of their second might be expired
- * after 30.1 seconds; circuits born at the beginning might be expired
- * after closer to 31 seconds.
- */
- #define MIN_SECONDS_BEFORE_EXPIRING_CIRC 30
- /** Close all circuits that start at us, aren't open, and were born
- * at least MIN_SECONDS_BEFORE_EXPIRING_CIRC seconds ago.
- */
- void circuit_expire_building(time_t now) {
- circuit_t *victim, *circ = global_circuitlist;
- while(circ) {
- victim = circ;
- circ = circ->next;
- if(!CIRCUIT_IS_ORIGIN(victim))
- continue; /* didn't originate here */
- if(victim->marked_for_close)
- continue; /* don't mess with marked circs */
- if(victim->timestamp_created + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now)
- continue; /* it's young still, don't mess with it */
- /* some debug logs, to help track bugs */
- if(victim->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING &&
- victim->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) {
- if(!victim->timestamp_dirty)
- log_fn(LOG_DEBUG,"Considering %sopen purp %d to %s (circid %d). (clean).",
- victim->state == CIRCUIT_STATE_OPEN ? "" : "non",
- victim->purpose, victim->build_state->chosen_exit_name,
- victim->n_circ_id);
- else
- log_fn(LOG_DEBUG,"Considering %sopen purp %d to %s (circid %d). %d secs since dirty.",
- victim->state == CIRCUIT_STATE_OPEN ? "" : "non",
- victim->purpose, victim->build_state->chosen_exit_name,
- victim->n_circ_id,
- (int)(now - victim->timestamp_dirty));
- }
- /* if circ is !open, or if it's open but purpose is a non-finished
- * intro or rend, then mark it for close */
- if(victim->state != CIRCUIT_STATE_OPEN ||
- victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND ||
- victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING ||
- victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO ||
- /* it's a rend_ready circ, but it's already picked a query */
- (victim->purpose == CIRCUIT_PURPOSE_C_REND_READY &&
- victim->rend_query[0]) ||
- /* c_rend_ready circs measure age since timestamp_dirty,
- * because that's set when they switch purposes
- */
- /* rend and intro circs become dirty each time they
- * make an introduction attempt. so timestamp_dirty
- * will reflect the time since the last attempt.
- */
- ((victim->purpose == CIRCUIT_PURPOSE_C_REND_READY ||
- victim->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED ||
- victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) &&
- victim->timestamp_dirty + MIN_SECONDS_BEFORE_EXPIRING_CIRC > now)) {
- if(victim->n_conn)
- log_fn(LOG_INFO,"Abandoning circ %s:%d:%d (state %d:%s, purpose %d)",
- victim->n_conn->address, victim->n_port, victim->n_circ_id,
- victim->state, circuit_state_to_string[victim->state], victim->purpose);
- else
- log_fn(LOG_INFO,"Abandoning circ %d (state %d:%s, purpose %d)", victim->n_circ_id,
- victim->state, circuit_state_to_string[victim->state], victim->purpose);
- circuit_log_path(LOG_INFO,victim);
- circuit_mark_for_close(victim);
- }
- }
- }
- /** How many circuits do we want simultaneously in-progress to handle
- * a given stream?
- */
- #define MIN_CIRCUITS_HANDLING_STREAM 2
- /** Return 1 if at least MIN_CIRCUITS_HANDLING_STREAM non-open
- * general-purpose circuits will have an acceptable exit node for
- * conn. Else return 0.
- */
- int circuit_stream_is_being_handled(connection_t *conn) {
- circuit_t *circ;
- routerinfo_t *exitrouter;
- int num=0;
- time_t now = time(NULL);
- for(circ=global_circuitlist;circ;circ = circ->next) {
- if(CIRCUIT_IS_ORIGIN(circ) && circ->state != CIRCUIT_STATE_OPEN &&
- !circ->marked_for_close && circ->purpose == CIRCUIT_PURPOSE_C_GENERAL &&
- (!circ->timestamp_dirty ||
- circ->timestamp_dirty + options.NewCircuitPeriod < now)) {
- exitrouter = router_get_by_digest(circ->build_state->chosen_exit_digest);
- if(exitrouter && connection_ap_can_use_exit(conn, exitrouter) != ADDR_POLICY_REJECTED)
- if(++num >= MIN_CIRCUITS_HANDLING_STREAM)
- return 1;
- }
- }
- return 0;
- }
- /** Build a new test circuit every 5 minutes */
- #define TESTING_CIRCUIT_INTERVAL 300
- /** This function is called once a second. Its job is to make sure
- * all services we offer have enough circuits available. Some
- * services just want enough circuits for current tasks, whereas
- * others want a minimum set of idle circuits hanging around.
- */
- void circuit_build_needed_circs(time_t now) {
- static long time_to_new_circuit = 0;
- circuit_t *circ;
- /* launch a new circ for any pending streams that need one */
- connection_ap_attach_pending();
- /* make sure any hidden services have enough intro points */
- rend_services_introduce();
- circ = circuit_get_youngest_clean_open(CIRCUIT_PURPOSE_C_GENERAL);
- if(time_to_new_circuit < now) {
- circuit_reset_failure_count();
- time_to_new_circuit = now + options.NewCircuitPeriod;
- if(proxy_mode())
- client_dns_clean();
- circuit_expire_old_circuits();
- if(options.RunTesting && circ &&
- circ->timestamp_created + TESTING_CIRCUIT_INTERVAL < now) {
- log_fn(LOG_INFO,"Creating a new testing circuit.");
- circuit_launch_by_identity(CIRCUIT_PURPOSE_C_GENERAL, NULL);
- }
- }
- /** How many simultaneous in-progress general-purpose circuits do we
- * want to be building at once, if there are no open general-purpose
- * circuits?
- */
- #define CIRCUIT_MIN_BUILDING_GENERAL 3
- /* if there's no open circ, and less than 3 are on the way,
- * go ahead and try another. */
- if(!circ && circuit_count_building(CIRCUIT_PURPOSE_C_GENERAL)
- < CIRCUIT_MIN_BUILDING_GENERAL) {
- circuit_launch_by_identity(CIRCUIT_PURPOSE_C_GENERAL, NULL);
- }
- /* XXX count idle rendezvous circs and build more */
- }
- /** If the stream <b>conn</b> is a member of any of the linked
- * lists of <b>circ</b>, then remove it from the list.
- */
- void circuit_detach_stream(circuit_t *circ, connection_t *conn) {
- connection_t *prevconn;
- tor_assert(circ && conn);
- if(conn == circ->p_streams) {
- circ->p_streams = conn->next_stream;
- return;
- }
- if(conn == circ->n_streams) {
- circ->n_streams = conn->next_stream;
- return;
- }
- if(conn == circ->resolving_streams) {
- circ->resolving_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;
- }
- for(prevconn = circ->resolving_streams;
- prevconn && prevconn->next_stream && prevconn->next_stream != conn;
- prevconn = prevconn->next_stream)
- ;
- if(prevconn && prevconn->next_stream) {
- prevconn->next_stream = conn->next_stream;
- return;
- }
- log_fn(LOG_ERR,"edge conn not in circuit's list?");
- tor_assert(0); /* should never get here */
- }
- /** Notify the global circuit list that <b>conn</b> is about to be
- * removed and then freed.
- *
- * If it's an OR conn, then mark-for-close all the circuits that use
- * that conn.
- *
- * If it's an edge conn, then detach it from its circ, so we don't
- * try to reference it later.
- */
- void circuit_about_to_close_connection(connection_t *conn) {
- /* currently, we assume it's too late to flush conn's buf here.
- * down the road, maybe we'll consider that eof doesn't mean can't-write
- */
- circuit_t *circ;
- switch(conn->type) {
- case CONN_TYPE_OR:
- if(conn->state != OR_CONN_STATE_OPEN) {
- /* Inform any pending (not attached) circs that they should give up. */
- circuit_n_conn_done(conn, 0);
- }
- /* Now close all the attached circuits on it. */
- while((circ = circuit_get_by_conn(conn))) {
- if(circ->n_conn == conn) /* it's closing in front of us */
- circ->n_conn = NULL;
- if(circ->p_conn == conn) /* it's closing behind us */
- circ->p_conn = NULL;
- circuit_mark_for_close(circ);
- }
- return;
- case CONN_TYPE_AP:
- case CONN_TYPE_EXIT:
- /* It's an edge conn. Need to remove it from the linked list of
- * conn's for this circuit. Confirm that 'end' relay command has
- * been sent. But don't kill the circuit.
- */
- circ = circuit_get_by_conn(conn);
- if(!circ)
- return;
- circuit_detach_stream(circ, conn);
- } /* end switch */
- }
- /** Don't keep more than 10 unused open circuits around. */
- #define MAX_UNUSED_OPEN_CIRCUITS 10
- /** Find each circuit that has been dirty for too long, and has
- * no streams on it: mark it for close.
- *
- * Also, if there are more than MAX_UNUSED_OPEN_CIRCUITS open and
- * unused circuits, then mark the excess circs for close.
- */
- static void
- circuit_expire_old_circuits(void)
- {
- circuit_t *circ;
- time_t now = time(NULL);
- smartlist_t *unused_open_circs;
- int i;
- unused_open_circs = smartlist_create();
- for (circ = global_circuitlist; circ; circ = circ->next) {
- if (circ->marked_for_close)
- continue;
- /* If the circuit has been dirty for too long, and there are no streams
- * on it, mark it for close.
- */
- if (circ->timestamp_dirty &&
- circ->timestamp_dirty + options.NewCircuitPeriod < now &&
- !circ->p_conn && /* we're the origin */
- !circ->p_streams /* nothing attached */ ) {
- log_fn(LOG_DEBUG,"Closing n_circ_id %d (dirty %d secs ago, purp %d)",circ->n_circ_id,
- (int)(now - circ->timestamp_dirty), circ->purpose);
- /* (only general and purpose_c circs can get dirty) */
- tor_assert(!circ->n_streams);
- tor_assert(circ->purpose <= CIRCUIT_PURPOSE_C_REND_JOINED);
- circuit_mark_for_close(circ);
- } else if (!circ->timestamp_dirty && CIRCUIT_IS_ORIGIN(circ) &&
- circ->state == CIRCUIT_STATE_OPEN &&
- circ->purpose == CIRCUIT_PURPOSE_C_GENERAL) {
- /* Also, gather a list of open unused general circuits that we created.
- * Because we add elements to the front of global_circuitlist,
- * the last elements of unused_open_circs will be the oldest
- * ones.
- */
- smartlist_add(unused_open_circs, circ);
- }
- }
- for (i = MAX_UNUSED_OPEN_CIRCUITS; i < smartlist_len(unused_open_circs); ++i) {
- circuit_t *circ = smartlist_get(unused_open_circs, i);
- log_fn(LOG_DEBUG,"Expiring excess clean circ (n_circ_id %d, purp %d)",
- circ->n_circ_id, circ->purpose);
- circuit_mark_for_close(circ);
- }
- smartlist_free(unused_open_circs);
- }
- /** The circuit <b>circ</b> has just become open. Take the next
- * step: for rendezvous circuits, we pass circ to the appropriate
- * function in rendclient or rendservice. For general circuits, we
- * call connection_ap_attach_pending, which looks for pending streams
- * that could use circ.
- */
- void circuit_has_opened(circuit_t *circ) {
- switch(circ->purpose) {
- case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
- rend_client_rendcirc_has_opened(circ);
- break;
- case CIRCUIT_PURPOSE_C_INTRODUCING:
- rend_client_introcirc_has_opened(circ);
- break;
- case CIRCUIT_PURPOSE_C_GENERAL:
- /* Tell any AP connections that have been waiting for a new
- * circuit that one is ready. */
- connection_ap_attach_pending();
- break;
- case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
- /* at Bob, waiting for introductions */
- rend_service_intro_has_opened(circ);
- break;
- case CIRCUIT_PURPOSE_S_CONNECT_REND:
- /* at Bob, connecting to rend point */
- rend_service_rendezvous_has_opened(circ);
- break;
- default:
- log_fn(LOG_ERR,"unhandled purpose %d",circ->purpose);
- tor_assert(0);
- }
- }
- /*~ Called whenever a circuit could not be successfully built.
- */
- void circuit_build_failed(circuit_t *circ) {
- /* we should examine circ and see if it failed because of
- * the last hop or an earlier hop. then use this info below.
- */
- int failed_at_last_hop = 0;
- /* If the last hop isn't open, and the second-to-last is, we failed
- * at the last hop. */
- if (circ->cpath &&
- circ->cpath->prev->state != CPATH_STATE_OPEN &&
- circ->cpath->prev->prev->state == CPATH_STATE_OPEN) {
- failed_at_last_hop = 1;
- }
- switch(circ->purpose) {
- case CIRCUIT_PURPOSE_C_GENERAL:
- if (circ->state != CIRCUIT_STATE_OPEN) {
- /* If we never built the circuit, note it as a failure. */
- /* Note that we can't just check circ->cpath here, because if
- * circuit-building failed immediately, it won't be set yet. */
- circuit_increment_failure_count();
- }
- break;
- case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
- /* at Bob, waiting for introductions */
- if (circ->state != CIRCUIT_STATE_OPEN) {
- circuit_increment_failure_count();
- }
- /* no need to care here, because bob will rebuild intro
- * points periodically. */
- break;
- case CIRCUIT_PURPOSE_C_INTRODUCING:
- /* at Alice, connecting to intro point */
- /* Don't increment failure count, since Bob may have picked
- * the introduction point maliciously */
- /* Alice will pick a new intro point when this one dies, if
- * the stream in question still cares. No need to act here. */
- break;
- case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
- /* at Alice, waiting for Bob */
- if (circ->state != CIRCUIT_STATE_OPEN) {
- circuit_increment_failure_count();
- }
- /* Alice will pick a new rend point when this one dies, if
- * the stream in question still cares. No need to act here. */
- break;
- case CIRCUIT_PURPOSE_S_CONNECT_REND:
- /* at Bob, connecting to rend point */
- /* Don't increment failure count, since Alice may have picked
- * the rendezvous point maliciously */
- if (failed_at_last_hop) {
- log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s. Sucks to be Alice.", circ->build_state->chosen_exit_name);
- } else {
- log_fn(LOG_INFO,"Couldn't connect to Alice's chosen rend point %s, because an earlier node failed.",
- circ->build_state->chosen_exit_name);
- rend_service_relaunch_rendezvous(circ);
- }
- break;
- default:
- /* Other cases are impossible, since this function is only called with
- * unbuilt circuits. */
- tor_assert(0);
- }
- }
- /** Number of consecutive failures so far; should only be touched by
- * circuit_launch_new and circuit_*_failure_count.
- */
- static int n_circuit_failures = 0;
- /** Don't retry launching a new circuit if we try this many times with no
- * success. */
- #define MAX_CIRCUIT_FAILURES 5
- circuit_t *circuit_launch_by_identity(uint8_t purpose, const char *exit_digest)
- {
- if (!has_fetched_directory) {
- log_fn(LOG_DEBUG,"Haven't fetched directory yet; cancelling circuit launch.");
- return NULL;
- }
- if (n_circuit_failures > MAX_CIRCUIT_FAILURES) {
- /* too many failed circs in a row. don't try. */
- // log_fn(LOG_INFO,"%d failures so far, not trying.",n_circuit_failures);
- return NULL;
- }
- /* try a circ. if it fails, circuit_mark_for_close will increment n_circuit_failures */
- return circuit_establish_circuit(purpose, exit_digest);
- }
- /** Launch a new circuit and return a pointer to it. Return NULL if you failed. */
- circuit_t *circuit_launch_by_nickname(uint8_t purpose, const char *exit_nickname)
- {
- const char *digest = NULL;
- if (exit_nickname) {
- routerinfo_t *r = router_get_by_nickname(exit_nickname);
- if (!r) {
- log_fn(LOG_WARN, "No such OR as '%s'", exit_nickname);
- return NULL;
- }
- digest = r->identity_digest;
- }
- return circuit_launch_by_identity(purpose, digest);
- }
- /** Record another failure at opening a general circuit. When we have
- * too many, we'll stop trying for the remainder of this minute.
- */
- static void circuit_increment_failure_count(void) {
- ++n_circuit_failures;
- log_fn(LOG_DEBUG,"n_circuit_failures now %d.",n_circuit_failures);
- }
- /** Reset the failure count for opening general circuits. This means
- * we will try MAX_CIRCUIT_FAILURES times more (if necessary) before
- * stopping again.
- */
- void circuit_reset_failure_count(void) {
- n_circuit_failures = 0;
- }
- /** Find an open circ that we're happy with: return 1. If there isn't
- * one, and there isn't one on the way, launch one and return 0. If it
- * will never work, return -1.
- *
- * Write the found or in-progress or launched circ into *circp.
- */
- static int
- circuit_get_open_circ_or_launch(connection_t *conn,
- uint8_t desired_circuit_purpose,
- circuit_t **circp) {
- circuit_t *circ;
- uint32_t addr;
- int is_resolve;
- tor_assert(conn);
- tor_assert(circp);
- tor_assert(conn->state == AP_CONN_STATE_CIRCUIT_WAIT);
- is_resolve = conn->socks_request->command == SOCKS_COMMAND_RESOLVE;
- circ = circuit_get_best(conn, 1, desired_circuit_purpose);
- if(circ) {
- *circp = circ;
- return 1; /* we're happy */
- }
- /* Do we need to check exit policy? */
- if(!is_resolve && !connection_edge_is_rendezvous_stream(conn)) {
- addr = client_dns_lookup_entry(conn->socks_request->address);
- if(router_exit_policy_all_routers_reject(addr, conn->socks_request->port)) {
- log_fn(LOG_WARN,"No Tor server exists that allows exit to %s:%d. Rejecting.",
- conn->socks_request->address, conn->socks_request->port);
- return -1;
- }
- }
- /* is one already on the way? */
- circ = circuit_get_best(conn, 0, desired_circuit_purpose);
- if(!circ) {
- char *exitname=NULL;
- uint8_t new_circ_purpose;
- if(desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
- /* need to pick an intro point */
- exitname = rend_client_get_random_intro(conn->rend_query);
- if(!exitname) {
- log_fn(LOG_WARN,"Couldn't get an intro point for '%s'. Closing conn.",
- conn->rend_query);
- return -1;
- }
- if(!router_get_by_nickname(exitname)) {
- log_fn(LOG_WARN,"Advertised intro point '%s' is not known. Closing.", exitname);
- return -1;
- }
- /* XXX if we failed, then refetch the descriptor */
- log_fn(LOG_INFO,"Chose %s as intro point for %s.", exitname, conn->rend_query);
- }
- if(desired_circuit_purpose == CIRCUIT_PURPOSE_C_REND_JOINED)
- new_circ_purpose = CIRCUIT_PURPOSE_C_ESTABLISH_REND;
- else if(desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT)
- new_circ_purpose = CIRCUIT_PURPOSE_C_INTRODUCING;
- else
- new_circ_purpose = desired_circuit_purpose;
- circ = circuit_launch_by_nickname(new_circ_purpose, exitname);
- tor_free(exitname);
- if(circ &&
- (desired_circuit_purpose != CIRCUIT_PURPOSE_C_GENERAL)) {
- /* then write the service_id into circ */
- strcpy(circ->rend_query, conn->rend_query);
- }
- }
- if(!circ)
- log_fn(LOG_INFO,"No safe circuit (purpose %d) ready for edge connection; delaying.",
- desired_circuit_purpose);
- *circp = circ;
- return 0;
- }
- /** Attach the AP stream <b>apconn</b> to circ's linked list of
- * p_streams. Also set apconn's cpath_layer to the last hop in
- * circ's cpath.
- */
- static void link_apconn_to_circ(connection_t *apconn, circuit_t *circ) {
- /* add it into the linked list of streams on this circuit */
- log_fn(LOG_DEBUG,"attaching new conn to circ. n_circ_id %d.", circ->n_circ_id);
- apconn->next_stream = circ->p_streams;
- /* assert_connection_ok(conn, time(NULL)); */
- circ->p_streams = apconn;
- tor_assert(CIRCUIT_IS_ORIGIN(circ) && circ->cpath && circ->cpath->prev);
- tor_assert(circ->cpath->prev->state == CPATH_STATE_OPEN);
- apconn->cpath_layer = circ->cpath->prev;
- }
- /** Try to find a safe live circuit for CONN_TYPE_AP connection conn. If
- * we don't find one: if conn cannot be handled by any known nodes,
- * warn and return -1 (conn needs to die);
- * else launch new circuit (if necessary) and return 0.
- * Otherwise, associate conn with a safe live circuit, do the
- * right next step, and return 1.
- */
- int connection_ap_handshake_attach_circuit(connection_t *conn) {
- int retval;
- int conn_age;
- tor_assert(conn);
- tor_assert(conn->type == CONN_TYPE_AP);
- tor_assert(conn->state == AP_CONN_STATE_CIRCUIT_WAIT);
- tor_assert(conn->socks_request);
- conn_age = time(NULL) - conn->timestamp_created;
- if(conn_age > 60) {
- /* XXX make this cleaner than '60' */
- log_fn(LOG_WARN,"Giving up on unattached conn (%d sec old).", conn_age);
- return -1;
- }
- if(!connection_edge_is_rendezvous_stream(conn)) { /* we're a general conn */
- circuit_t *circ=NULL;
- /* find the circuit that we should use, if there is one. */
- retval = circuit_get_open_circ_or_launch(conn, CIRCUIT_PURPOSE_C_GENERAL, &circ);
- if(retval < 1)
- return retval;
- /* We have found a suitable circuit for our conn. Hurray. */
- log_fn(LOG_DEBUG,"Attaching apconn to general circ %d (stream %d sec old).",
- circ->n_circ_id, conn_age);
- /* here, print the circ's path. so people can figure out which circs are sucking. */
- circuit_log_path(LOG_INFO,circ);
- if(!circ->timestamp_dirty)
- circ->timestamp_dirty = time(NULL);
- link_apconn_to_circ(conn, circ);
- tor_assert(conn->socks_request);
- if (conn->socks_request->command == SOCKS_COMMAND_CONNECT)
- connection_ap_handshake_send_begin(conn, circ);
- else
- connection_ap_handshake_send_resolve(conn, circ);
- return 1;
- } else { /* we're a rendezvous conn */
- circuit_t *rendcirc=NULL, *introcirc=NULL;
- tor_assert(!conn->cpath_layer);
- /* start by finding a rendezvous circuit for us */
- retval = circuit_get_open_circ_or_launch(conn, CIRCUIT_PURPOSE_C_REND_JOINED, &rendcirc);
- if(retval < 0) return -1; /* failed */
- tor_assert(rendcirc);
- if(retval > 0) {
- /* one is already established, attach */
- log_fn(LOG_INFO,"rend joined circ %d already here. attaching. (stream %d sec old)",
- rendcirc->n_circ_id, conn_age);
- link_apconn_to_circ(conn, rendcirc);
- if(connection_ap_handshake_send_begin(conn, rendcirc) < 0)
- return 0; /* already marked, let them fade away */
- return 1;
- }
- if(rendcirc->purpose == CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) {
- log_fn(LOG_INFO,"pending-join circ %d already here, with intro ack. Stalling. (stream %d sec old)", rendcirc->n_circ_id, conn_age);
- return 0;
- }
- /* it's on its way. find an intro circ. */
- retval = circuit_get_open_circ_or_launch(conn, CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT, &introcirc);
- if(retval < 0) return -1; /* failed */
- tor_assert(introcirc);
- if(retval > 0) {
- /* one has already sent the intro. keep waiting. */
- log_fn(LOG_INFO,"Intro circ %d present and awaiting ack (rend %d). Stalling. (stream %d sec old)",
- introcirc->n_circ_id, rendcirc->n_circ_id, conn_age);
- return 0;
- }
- /* now both rendcirc and introcirc are defined, and neither is finished */
- if(rendcirc->purpose == CIRCUIT_PURPOSE_C_REND_READY) {
- log_fn(LOG_INFO,"ready rend circ %d already here (no intro-ack yet on intro %d). (stream %d sec old)",
- rendcirc->n_circ_id, introcirc->n_circ_id, conn_age);
- /* look around for any new intro circs that should introduce */
- tor_assert(introcirc->purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
- if(introcirc->state == CIRCUIT_STATE_OPEN) {
- log_fn(LOG_INFO,"found open intro circ %d (rend %d); sending introduction. (stream %d sec old)",
- introcirc->n_circ_id, rendcirc->n_circ_id, conn_age);
- /* XXX here we should cannibalize the rend circ if it's a zero service id */
- if(rend_client_send_introduction(introcirc, rendcirc) < 0) {
- return -1;
- }
- rendcirc->timestamp_dirty = time(NULL);
- introcirc->timestamp_dirty = time(NULL);
- assert_circuit_ok(rendcirc);
- assert_circuit_ok(introcirc);
- return 0;
- }
- }
- log_fn(LOG_INFO,"Intro (%d) and rend (%d) circs are not both ready. Stalling conn. (%d sec old)", introcirc->n_circ_id, rendcirc->n_circ_id, conn_age);
- return 0;
- }
- }
- /*
- Local Variables:
- mode:c
- indent-tabs-mode:nil
- c-basic-offset:2
- End:
- */
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