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tor/src/or/circuituse.c
George Kadianakis 5c4f4acedb prop224: Function to inc/decrement num rendezvous stream 
Add a common function for both legacy and prop224 hidden service to increment
and decrement the rendezvous stream counter on an origin circuit.

Signed-off-by: David Goulet <dgoulet@torproject.org>
2017-08-08 20:29:35 -04:00

2831 lines
107 KiB
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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2017, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file circuituse.c
* \brief Launch the right sort of circuits and attach the right streams to
* them.
*
* As distinct from circuitlist.c, which manages lookups to find circuits, and
* circuitbuild.c, which handles the logistics of circuit construction, this
* module keeps track of which streams can be attached to which circuits (in
* circuit_get_best()), and attaches streams to circuits (with
* circuit_try_attaching_streams(), connection_ap_handshake_attach_circuit(),
* and connection_ap_handshake_attach_chosen_circuit() ).
*
* This module also makes sure that we are building circuits for all of the
* predicted ports, using circuit_remove_handled_ports(),
* circuit_stream_is_being_handled(), and circuit_build_needed_cirs(). It
* handles launching circuits for specific targets using
* circuit_launch_by_extend_info().
*
* This is also where we handle expiring circuits that have been around for
* too long without actually completing, along with the circuit_build_timeout
* logic in circuitstats.c.
**/
#include "or.h"
#include "addressmap.h"
#include "bridges.h"
#include "channel.h"
#include "circpathbias.h"
#include "circuitbuild.h"
#include "circuitlist.h"
#include "circuitstats.h"
#include "circuituse.h"
#include "config.h"
#include "connection.h"
#include "connection_edge.h"
#include "control.h"
#include "entrynodes.h"
#include "hs_common.h"
#include "hs_client.h"
#include "hs_circuit.h"
#include "hs_ident.h"
#include "nodelist.h"
#include "networkstatus.h"
#include "policies.h"
#include "rendclient.h"
#include "rendcommon.h"
#include "rendservice.h"
#include "rephist.h"
#include "router.h"
#include "routerlist.h"
static void circuit_expire_old_circuits_clientside(void);
static void circuit_increment_failure_count(void);
/** Check whether the hidden service destination of the stream at
* <b>edge_conn</b> is the same as the destination of the circuit at
* <b>origin_circ</b>. */
static int
circuit_matches_with_rend_stream(const edge_connection_t *edge_conn,
const origin_circuit_t *origin_circ)
{
/* Check if this is a v2 rendezvous circ/stream */
if ((edge_conn->rend_data && !origin_circ->rend_data) ||
(!edge_conn->rend_data && origin_circ->rend_data) ||
(edge_conn->rend_data && origin_circ->rend_data &&
rend_cmp_service_ids(rend_data_get_address(edge_conn->rend_data),
rend_data_get_address(origin_circ->rend_data)))) {
/* this circ is not for this conn */
return 0;
}
/* Check if this is a v3 rendezvous circ/stream */
if ((edge_conn->hs_ident && !origin_circ->hs_ident) ||
(!edge_conn->hs_ident && origin_circ->hs_ident) ||
(edge_conn->hs_ident && origin_circ->hs_ident &&
!ed25519_pubkey_eq(&edge_conn->hs_ident->identity_pk,
&origin_circ->hs_ident->identity_pk))) {
/* this circ is not for this conn */
return 0;
}
return 1;
}
/** Return 1 if <b>circ</b> could be returned by circuit_get_best().
* Else return 0.
*/
static int
circuit_is_acceptable(const origin_circuit_t *origin_circ,
const entry_connection_t *conn,
int must_be_open, uint8_t purpose,
int need_uptime, int need_internal,
time_t now)
{
const circuit_t *circ = TO_CIRCUIT(origin_circ);
const node_t *exitnode;
cpath_build_state_t *build_state;
tor_assert(circ);
tor_assert(conn);
tor_assert(conn->socks_request);
if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_chan))
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 this is a timed-out hidden service circuit, skip it. */
if (origin_circ->hs_circ_has_timed_out) {
return 0;
}
if (purpose == CIRCUIT_PURPOSE_C_GENERAL ||
purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
if (circ->timestamp_dirty &&
circ->timestamp_dirty+get_options()->MaxCircuitDirtiness <= now)
return 0;
}
if (origin_circ->unusable_for_new_conns)
return 0;
/* 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 service hop. so just check the nickname
* of the one we meant to finish at.
*/
build_state = origin_circ->build_state;
exitnode = build_state_get_exit_node(build_state);
if (need_uptime && !build_state->need_uptime)
return 0;
if (need_internal != build_state->is_internal)
return 0;
if (purpose == CIRCUIT_PURPOSE_C_GENERAL) {
tor_addr_t addr;
const int family = tor_addr_parse(&addr, conn->socks_request->address);
if (!exitnode && !build_state->onehop_tunnel) {
log_debug(LD_CIRC,"Not considering circuit with unknown router.");
return 0; /* this circuit is screwed and doesn't know it yet,
* or is a rendezvous circuit. */
}
if (build_state->onehop_tunnel) {
if (!conn->want_onehop) {
log_debug(LD_CIRC,"Skipping one-hop circuit.");
return 0;
}
tor_assert(conn->chosen_exit_name);
if (build_state->chosen_exit) {
char digest[DIGEST_LEN];
if (hexdigest_to_digest(conn->chosen_exit_name, digest) < 0)
return 0; /* broken digest, we don't want it */
if (tor_memneq(digest, build_state->chosen_exit->identity_digest,
DIGEST_LEN))
return 0; /* this is a circuit to somewhere else */
if (tor_digest_is_zero(digest)) {
/* we don't know the digest; have to compare addr:port */
if (family < 0 ||
!tor_addr_eq(&build_state->chosen_exit->addr, &addr) ||
build_state->chosen_exit->port != conn->socks_request->port)
return 0;
}
}
} else {
if (conn->want_onehop) {
/* don't use three-hop circuits -- that could hurt our anonymity. */
return 0;
}
}
if (origin_circ->prepend_policy && family != -1) {
int r = compare_tor_addr_to_addr_policy(&addr,
conn->socks_request->port,
origin_circ->prepend_policy);
if (r == ADDR_POLICY_REJECTED)
return 0;
}
if (exitnode && !connection_ap_can_use_exit(conn, exitnode)) {
/* can't exit from this router */
return 0;
}
} else { /* not general: this might be a rend circuit */
const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(conn);
if (!circuit_matches_with_rend_stream(edge_conn, origin_circ)) {
return 0;
}
}
if (!connection_edge_compatible_with_circuit(conn, origin_circ)) {
/* conn needs to be isolated from other conns that have already used
* origin_circ */
return 0;
}
return 1;
}
/** Return 1 if circuit <b>a</b> is better than circuit <b>b</b> for
* <b>conn</b>, and return 0 otherwise. Used by circuit_get_best.
*/
static int
circuit_is_better(const origin_circuit_t *oa, const origin_circuit_t *ob,
const entry_connection_t *conn)
{
const circuit_t *a = TO_CIRCUIT(oa);
const circuit_t *b = TO_CIRCUIT(ob);
const uint8_t purpose = ENTRY_TO_CONN(conn)->purpose;
int a_bits, b_bits;
/* If one of the circuits was allowed to live due to relaxing its timeout,
* it is definitely worse (it's probably a much slower path). */
if (oa->relaxed_timeout && !ob->relaxed_timeout)
return 0; /* ob is better. It's not relaxed. */
if (!oa->relaxed_timeout && ob->relaxed_timeout)
return 1; /* oa is better. It's not relaxed. */
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 ||
timercmp(&a->timestamp_began, &b->timestamp_began, OP_GT))
return 1;
if (ob->build_state->is_internal)
/* XXXX++ what the heck is this internal thing doing here. I
* think we can get rid of it. circuit_is_acceptable() already
* makes sure that is_internal is exactly what we need it to
* be. -RD */
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;
}
/* XXXX Maybe this check should get a higher priority to avoid
* using up circuits too rapidly. */
a_bits = connection_edge_update_circuit_isolation(conn,
(origin_circuit_t*)oa, 1);
b_bits = connection_edge_update_circuit_isolation(conn,
(origin_circuit_t*)ob, 1);
/* if x_bits < 0, then we have not used x for anything; better not to dirty
* a connection if we can help it. */
if (a_bits < 0) {
return 0;
} else if (b_bits < 0) {
return 1;
}
a_bits &= ~ oa->isolation_flags_mixed;
a_bits &= ~ ob->isolation_flags_mixed;
if (n_bits_set_u8(a_bits) < n_bits_set_u8(b_bits)) {
/* The fewer new restrictions we need to make on a circuit for stream
* isolation, the better. */
return 1;
}
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 origin_circuit_t *
circuit_get_best(const entry_connection_t *conn,
int must_be_open, uint8_t purpose,
int need_uptime, int need_internal)
{
origin_circuit_t *best=NULL;
struct timeval now;
int intro_going_on_but_too_old = 0;
tor_assert(conn);
tor_assert(purpose == CIRCUIT_PURPOSE_C_GENERAL ||
purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT ||
purpose == CIRCUIT_PURPOSE_C_REND_JOINED);
tor_gettimeofday(&now);
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
origin_circuit_t *origin_circ;
if (!CIRCUIT_IS_ORIGIN(circ))
continue;
origin_circ = TO_ORIGIN_CIRCUIT(circ);
/* Log an info message if we're going to launch a new intro circ in
* parallel */
if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT &&
!must_be_open && origin_circ->hs_circ_has_timed_out) {
intro_going_on_but_too_old = 1;
continue;
}
if (!circuit_is_acceptable(origin_circ,conn,must_be_open,purpose,
need_uptime,need_internal, (time_t)now.tv_sec))
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(origin_circ,best,conn))
best = origin_circ;
}
SMARTLIST_FOREACH_END(circ);
if (!best && intro_going_on_but_too_old)
log_info(LD_REND|LD_CIRC, "There is an intro circuit being created "
"right now, but it has already taken quite a while. Starting "
"one in parallel.");
return best;
}
/** Return the number of not-yet-open general-purpose origin circuits. */
static int
count_pending_general_client_circuits(void)
{
int count = 0;
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (circ->marked_for_close ||
circ->state == CIRCUIT_STATE_OPEN ||
circ->purpose != CIRCUIT_PURPOSE_C_GENERAL ||
!CIRCUIT_IS_ORIGIN(circ))
continue;
++count;
}
SMARTLIST_FOREACH_END(circ);
return count;
}
#if 0
/** Check whether, according to the policies in <b>options</b>, the
* circuit <b>circ</b> makes sense. */
/* XXXX currently only checks Exclude{Exit}Nodes; it should check more.
* Also, it doesn't have the right definition of an exit circuit. Also,
* it's never called. */
int
circuit_conforms_to_options(const origin_circuit_t *circ,
const or_options_t *options)
{
const crypt_path_t *cpath, *cpath_next = NULL;
/* first check if it includes any excluded nodes */
for (cpath = circ->cpath; cpath_next != circ->cpath; cpath = cpath_next) {
cpath_next = cpath->next;
if (routerset_contains_extendinfo(options->ExcludeNodes,
cpath->extend_info))
return 0;
}
/* then consider the final hop */
if (routerset_contains_extendinfo(options->ExcludeExitNodes,
circ->cpath->prev->extend_info))
return 0;
return 1;
}
#endif
/** Close all circuits that start at us, aren't open, and were born
* at least CircuitBuildTimeout seconds ago.
*/
void
circuit_expire_building(void)
{
/* circ_times.timeout_ms and circ_times.close_ms are from
* circuit_build_times_get_initial_timeout() if we haven't computed
* custom timeouts yet */
struct timeval general_cutoff, begindir_cutoff, fourhop_cutoff,
close_cutoff, extremely_old_cutoff, hs_extremely_old_cutoff,
cannibalized_cutoff, c_intro_cutoff, s_intro_cutoff, stream_cutoff;
const or_options_t *options = get_options();
struct timeval now;
cpath_build_state_t *build_state;
int any_opened_circs = 0;
tor_gettimeofday(&now);
/* Check to see if we have any opened circuits. If we don't,
* we want to be more lenient with timeouts, in case the
* user has relocated and/or changed network connections.
* See bug #3443. */
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, next_circ) {
if (!CIRCUIT_IS_ORIGIN(next_circ) || /* didn't originate here */
next_circ->marked_for_close) { /* don't mess with marked circs */
continue;
}
if (TO_ORIGIN_CIRCUIT(next_circ)->has_opened &&
next_circ->state == CIRCUIT_STATE_OPEN &&
TO_ORIGIN_CIRCUIT(next_circ)->build_state &&
TO_ORIGIN_CIRCUIT(next_circ)->build_state->desired_path_len
== DEFAULT_ROUTE_LEN) {
any_opened_circs = 1;
break;
}
} SMARTLIST_FOREACH_END(next_circ);
#define SET_CUTOFF(target, msec) do { \
long ms = tor_lround(msec); \
struct timeval diff; \
diff.tv_sec = ms / 1000; \
diff.tv_usec = (int)((ms % 1000) * 1000); \
timersub(&now, &diff, &target); \
} while (0)
/**
* Because circuit build timeout is calculated only based on 3 hop
* general purpose circuit construction, we need to scale the timeout
* to make it properly apply to longer circuits, and circuits of
* certain usage types. The following diagram illustrates how we
* derive the scaling below. In short, we calculate the number
* of times our telescoping-based circuit construction causes cells
* to traverse each link for the circuit purpose types in question,
* and then assume each link is equivalent.
*
* OP --a--> A --b--> B --c--> C
* OP --a--> A --b--> B --c--> C --d--> D
*
* Let h = a = b = c = d
*
* Three hops (general_cutoff)
* RTTs = 3a + 2b + c
* RTTs = 6h
* Cannibalized:
* RTTs = a+b+c+d
* RTTs = 4h
* Four hops:
* RTTs = 4a + 3b + 2c + d
* RTTs = 10h
* Client INTRODUCE1+ACK: // XXX: correct?
* RTTs = 5a + 4b + 3c + 2d
* RTTs = 14h
* Server intro:
* RTTs = 4a + 3b + 2c
* RTTs = 9h
*/
SET_CUTOFF(general_cutoff, get_circuit_build_timeout_ms());
SET_CUTOFF(begindir_cutoff, get_circuit_build_timeout_ms());
/* > 3hop circs seem to have a 1.0 second delay on their cannibalized
* 4th hop. */
SET_CUTOFF(fourhop_cutoff, get_circuit_build_timeout_ms() * (10/6.0) + 1000);
/* CIRCUIT_PURPOSE_C_ESTABLISH_REND behaves more like a RELAY cell.
* Use the stream cutoff (more or less). */
SET_CUTOFF(stream_cutoff, MAX(options->CircuitStreamTimeout,15)*1000 + 1000);
/* Be lenient with cannibalized circs. They already survived the official
* CBT, and they're usually not performance-critical. */
SET_CUTOFF(cannibalized_cutoff,
MAX(get_circuit_build_close_time_ms()*(4/6.0),
options->CircuitStreamTimeout * 1000) + 1000);
/* Intro circs have an extra round trip (and are also 4 hops long) */
SET_CUTOFF(c_intro_cutoff, get_circuit_build_timeout_ms() * (14/6.0) + 1000);
/* Server intro circs have an extra round trip */
SET_CUTOFF(s_intro_cutoff, get_circuit_build_timeout_ms() * (9/6.0) + 1000);
SET_CUTOFF(close_cutoff, get_circuit_build_close_time_ms());
SET_CUTOFF(extremely_old_cutoff, get_circuit_build_close_time_ms()*2 + 1000);
SET_CUTOFF(hs_extremely_old_cutoff,
MAX(get_circuit_build_close_time_ms()*2 + 1000,
options->SocksTimeout * 1000));
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *,victim) {
struct timeval cutoff;
if (!CIRCUIT_IS_ORIGIN(victim) || /* didn't originate here */
victim->marked_for_close) /* don't mess with marked circs */
continue;
/* If we haven't yet started the first hop, it means we don't have
* any orconns available, and thus have not started counting time yet
* for this circuit. See circuit_deliver_create_cell() and uses of
* timestamp_began.
*
* Continue to wait in this case. The ORConn should timeout
* independently and kill us then.
*/
if (TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_CLOSED) {
continue;
}
build_state = TO_ORIGIN_CIRCUIT(victim)->build_state;
if (build_state && build_state->onehop_tunnel)
cutoff = begindir_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT)
cutoff = close_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING ||
victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT)
cutoff = c_intro_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO)
cutoff = s_intro_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND)
cutoff = stream_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING)
cutoff = close_cutoff;
else if (TO_ORIGIN_CIRCUIT(victim)->has_opened &&
victim->state != CIRCUIT_STATE_OPEN)
cutoff = cannibalized_cutoff;
else if (build_state && build_state->desired_path_len >= 4)
cutoff = fourhop_cutoff;
else
cutoff = general_cutoff;
if (TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out)
cutoff = hs_extremely_old_cutoff;
if (timercmp(&victim->timestamp_began, &cutoff, OP_GT))
continue; /* it's still young, leave it alone */
/* We need to double-check the opened state here because
* we don't want to consider opened 1-hop dircon circuits for
* deciding when to relax the timeout, but we *do* want to relax
* those circuits too if nothing else is opened *and* they still
* aren't either. */
if (!any_opened_circs && victim->state != CIRCUIT_STATE_OPEN) {
/* It's still young enough that we wouldn't close it, right? */
if (timercmp(&victim->timestamp_began, &close_cutoff, OP_GT)) {
if (!TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout) {
int first_hop_succeeded = TO_ORIGIN_CIRCUIT(victim)->cpath->state
== CPATH_STATE_OPEN;
log_info(LD_CIRC,
"No circuits are opened. Relaxing timeout for circuit %d "
"(a %s %d-hop circuit in state %s with channel state %s).",
TO_ORIGIN_CIRCUIT(victim)->global_identifier,
circuit_purpose_to_string(victim->purpose),
TO_ORIGIN_CIRCUIT(victim)->build_state ?
TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len :
-1,
circuit_state_to_string(victim->state),
channel_state_to_string(victim->n_chan->state));
/* We count the timeout here for CBT, because technically this
* was a timeout, and the timeout value needs to reset if we
* see enough of them. Note this means we also need to avoid
* double-counting below, too. */
circuit_build_times_count_timeout(get_circuit_build_times_mutable(),
first_hop_succeeded);
TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout = 1;
}
continue;
} else {
static ratelim_t relax_timeout_limit = RATELIM_INIT(3600);
const double build_close_ms = get_circuit_build_close_time_ms();
log_fn_ratelim(&relax_timeout_limit, LOG_NOTICE, LD_CIRC,
"No circuits are opened. Relaxed timeout for circuit %d "
"(a %s %d-hop circuit in state %s with channel state %s) to "
"%ldms. However, it appears the circuit has timed out "
"anyway.",
TO_ORIGIN_CIRCUIT(victim)->global_identifier,
circuit_purpose_to_string(victim->purpose),
TO_ORIGIN_CIRCUIT(victim)->build_state ?
TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len :
-1,
circuit_state_to_string(victim->state),
channel_state_to_string(victim->n_chan->state),
(long)build_close_ms);
}
}
#if 0
/* 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 purpose %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 purpose %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));
}
#endif
/* 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) {
switch (victim->purpose) {
default: /* most open circuits can be left alone. */
continue; /* yes, continue inside a switch refers to the nearest
* enclosing loop. C is smart. */
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
break; /* too old, need to die */
case CIRCUIT_PURPOSE_C_REND_READY:
/* it's a rend_ready circ -- has it already picked a query? */
/* c_rend_ready circs measure age since timestamp_dirty,
* because that's set when they switch purposes
*/
if (TO_ORIGIN_CIRCUIT(victim)->rend_data ||
victim->timestamp_dirty > cutoff.tv_sec)
continue;
break;
case CIRCUIT_PURPOSE_PATH_BIAS_TESTING:
/* Open path bias testing circuits are given a long
* time to complete the test, but not forever */
TO_ORIGIN_CIRCUIT(victim)->path_state = PATH_STATE_USE_FAILED;
break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* We keep old introducing circuits around for
* a while in parallel, and they can end up "opened".
* We decide below if we're going to mark them timed
* out and eventually close them.
*/
break;
case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED:
case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT:
/* rend and intro circs become dirty each time they
* make an introduction attempt. so timestamp_dirty
* will reflect the time since the last attempt.
*/
if (victim->timestamp_dirty > cutoff.tv_sec)
continue;
break;
}
} else { /* circuit not open, consider recording failure as timeout */
int first_hop_succeeded = TO_ORIGIN_CIRCUIT(victim)->cpath &&
TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_OPEN;
if (TO_ORIGIN_CIRCUIT(victim)->p_streams != NULL) {
log_warn(LD_BUG, "Circuit %d (purpose %d, %s) has timed out, "
"yet has attached streams!",
TO_ORIGIN_CIRCUIT(victim)->global_identifier,
victim->purpose,
circuit_purpose_to_string(victim->purpose));
tor_fragile_assert();
continue;
}
if (circuit_timeout_want_to_count_circ(TO_ORIGIN_CIRCUIT(victim)) &&
circuit_build_times_enough_to_compute(get_circuit_build_times())) {
/* Circuits are allowed to last longer for measurement.
* Switch their purpose and wait. */
if (victim->purpose != CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) {
control_event_circuit_status(TO_ORIGIN_CIRCUIT(victim),
CIRC_EVENT_FAILED,
END_CIRC_REASON_TIMEOUT);
circuit_change_purpose(victim, CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT);
/* Record this failure to check for too many timeouts
* in a row. This function does not record a time value yet
* (we do that later); it only counts the fact that we did
* have a timeout. We also want to avoid double-counting
* already "relaxed" circuits, which are counted above. */
if (!TO_ORIGIN_CIRCUIT(victim)->relaxed_timeout) {
circuit_build_times_count_timeout(
get_circuit_build_times_mutable(),
first_hop_succeeded);
}
continue;
}
/*
* If the circuit build time is much greater than we would have cut
* it off at, we probably had a suspend event along this codepath,
* and we should discard the value.
*/
if (timercmp(&victim->timestamp_began, &extremely_old_cutoff, OP_LT)) {
log_notice(LD_CIRC,
"Extremely large value for circuit build timeout: %lds. "
"Assuming clock jump. Purpose %d (%s)",
(long)(now.tv_sec - victim->timestamp_began.tv_sec),
victim->purpose,
circuit_purpose_to_string(victim->purpose));
} else if (circuit_build_times_count_close(
get_circuit_build_times_mutable(),
first_hop_succeeded,
(time_t)victim->timestamp_created.tv_sec)) {
circuit_build_times_set_timeout(get_circuit_build_times_mutable());
}
}
}
/* If this is a hidden service client circuit which is far enough along in
* connecting to its destination, and we haven't already flagged it as
* 'timed out', flag it so we'll launch another intro or rend circ, but
* don't mark it for close yet.
*
* (Circs flagged as 'timed out' are given a much longer timeout
* period above, so we won't close them in the next call to
* circuit_expire_building.) */
if (!(TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out)) {
switch (victim->purpose) {
case CIRCUIT_PURPOSE_C_REND_READY:
/* We only want to spare a rend circ if it has been specified in
* an INTRODUCE1 cell sent to a hidden service. A circ's
* pending_final_cpath field is non-NULL iff it is a rend circ
* and we have tried to send an INTRODUCE1 cell specifying it.
* Thus, if the pending_final_cpath field *is* NULL, then we
* want to not spare it. */
if (TO_ORIGIN_CIRCUIT(victim)->build_state &&
TO_ORIGIN_CIRCUIT(victim)->build_state->pending_final_cpath ==
NULL)
break;
/* fallthrough! */
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* connection_ap_handshake_attach_circuit() will relaunch for us */
case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT:
case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED:
/* If we have reached this line, we want to spare the circ for now. */
log_info(LD_CIRC,"Marking circ %u (state %d:%s, purpose %d) "
"as timed-out HS circ",
(unsigned)victim->n_circ_id,
victim->state, circuit_state_to_string(victim->state),
victim->purpose);
TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out = 1;
continue;
default:
break;
}
}
/* If this is a service-side rendezvous circuit which is far
* enough along in connecting to its destination, consider sparing
* it. */
if (!(TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out) &&
victim->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) {
log_info(LD_CIRC,"Marking circ %u (state %d:%s, purpose %d) "
"as timed-out HS circ; relaunching rendezvous attempt.",
(unsigned)victim->n_circ_id,
victim->state, circuit_state_to_string(victim->state),
victim->purpose);
TO_ORIGIN_CIRCUIT(victim)->hs_circ_has_timed_out = 1;
hs_circ_retry_service_rendezvous_point(TO_ORIGIN_CIRCUIT(victim));
continue;
}
if (victim->n_chan)
log_info(LD_CIRC,
"Abandoning circ %u %s:%u (state %d,%d:%s, purpose %d, "
"len %d)", TO_ORIGIN_CIRCUIT(victim)->global_identifier,
channel_get_canonical_remote_descr(victim->n_chan),
(unsigned)victim->n_circ_id,
TO_ORIGIN_CIRCUIT(victim)->has_opened,
victim->state, circuit_state_to_string(victim->state),
victim->purpose,
TO_ORIGIN_CIRCUIT(victim)->build_state ?
TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len :
-1);
else
log_info(LD_CIRC,
"Abandoning circ %u %u (state %d,%d:%s, purpose %d, len %d)",
TO_ORIGIN_CIRCUIT(victim)->global_identifier,
(unsigned)victim->n_circ_id,
TO_ORIGIN_CIRCUIT(victim)->has_opened,
victim->state,
circuit_state_to_string(victim->state), victim->purpose,
TO_ORIGIN_CIRCUIT(victim)->build_state ?
TO_ORIGIN_CIRCUIT(victim)->build_state->desired_path_len :
-1);
circuit_log_path(LOG_INFO,LD_CIRC,TO_ORIGIN_CIRCUIT(victim));
if (victim->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT)
circuit_mark_for_close(victim, END_CIRC_REASON_MEASUREMENT_EXPIRED);
else
circuit_mark_for_close(victim, END_CIRC_REASON_TIMEOUT);
pathbias_count_timeout(TO_ORIGIN_CIRCUIT(victim));
} SMARTLIST_FOREACH_END(victim);
}
/**
* Mark for close all circuits that start here, that were built through a
* guard we weren't sure if we wanted to use, and that have been waiting
* around for way too long.
*/
void
circuit_expire_waiting_for_better_guard(void)
{
SMARTLIST_FOREACH_BEGIN(circuit_get_global_origin_circuit_list(),
origin_circuit_t *, circ) {
if (TO_CIRCUIT(circ)->marked_for_close)
continue;
if (circ->guard_state == NULL)
continue;
if (entry_guard_state_should_expire(circ->guard_state))
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_NONE);
} SMARTLIST_FOREACH_END(circ);
}
/** For debugging #8387: track when we last called
* circuit_expire_old_circuits_clientside. */
static time_t last_expired_clientside_circuits = 0;
/**
* As a diagnostic for bug 8387, log information about how many one-hop
* circuits we have around that have been there for at least <b>age</b>
* seconds. Log a few of them.
* Ignores Single Onion Service intro and Tor2web redezvous circuits, they are
* expected to be long-term one-hop circuits.
*/
void
circuit_log_ancient_one_hop_circuits(int age)
{
#define MAX_ANCIENT_ONEHOP_CIRCUITS_TO_LOG 10
time_t now = time(NULL);
time_t cutoff = now - age;
int n_found = 0;
smartlist_t *log_these = smartlist_new();
const or_options_t *options = get_options();
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
const origin_circuit_t *ocirc;
if (! CIRCUIT_IS_ORIGIN(circ))
continue;
if (circ->timestamp_created.tv_sec >= cutoff)
continue;
/* Single Onion Services deliberately make long term one-hop intro
* connections. We only ignore active intro point connections, if we take
* a long time establishing, that's worth logging. */
if (rend_service_allow_non_anonymous_connection(options) &&
circ->purpose == CIRCUIT_PURPOSE_S_INTRO)
continue;
/* Tor2web deliberately makes long term one-hop rend connections,
* particularly when Tor2webRendezvousPoints is used. We only ignore
* active rend point connections, if we take a long time to rendezvous,
* that's worth logging. */
if (rend_client_allow_non_anonymous_connection(options) &&
circ->purpose == CIRCUIT_PURPOSE_C_REND_JOINED)
continue;
ocirc = CONST_TO_ORIGIN_CIRCUIT(circ);
if (ocirc->build_state && ocirc->build_state->onehop_tunnel) {
++n_found;
if (smartlist_len(log_these) < MAX_ANCIENT_ONEHOP_CIRCUITS_TO_LOG)
smartlist_add(log_these, (origin_circuit_t*) ocirc);
}
}
SMARTLIST_FOREACH_END(circ);
if (n_found == 0)
goto done;
log_notice(LD_HEARTBEAT,
"Diagnostic for issue 8387: Found %d one-hop circuits more "
"than %d seconds old! Logging %d...",
n_found, age, smartlist_len(log_these));
SMARTLIST_FOREACH_BEGIN(log_these, const origin_circuit_t *, ocirc) {
char created[ISO_TIME_LEN+1];
int stream_num;
const edge_connection_t *conn;
char *dirty = NULL;
const circuit_t *circ = TO_CIRCUIT(ocirc);
format_local_iso_time(created,
(time_t)circ->timestamp_created.tv_sec);
if (circ->timestamp_dirty) {
char dirty_since[ISO_TIME_LEN+1];
format_local_iso_time(dirty_since, circ->timestamp_dirty);
tor_asprintf(&dirty, "Dirty since %s (%ld seconds vs %ld-second cutoff)",
dirty_since, (long)(now - circ->timestamp_dirty),
(long) options->MaxCircuitDirtiness);
} else {
dirty = tor_strdup("Not marked dirty");
}
log_notice(LD_HEARTBEAT, " #%d created at %s. %s, %s. %s for close. "
"Package window: %d. "
"%s for new conns. %s.",
ocirc_sl_idx,
created,
circuit_state_to_string(circ->state),
circuit_purpose_to_string(circ->purpose),
circ->marked_for_close ? "Marked" : "Not marked",
circ->package_window,
ocirc->unusable_for_new_conns ? "Not usable" : "usable",
dirty);
tor_free(dirty);
stream_num = 0;
for (conn = ocirc->p_streams; conn; conn = conn->next_stream) {
const connection_t *c = TO_CONN(conn);
char stream_created[ISO_TIME_LEN+1];
if (++stream_num >= 5)
break;
format_local_iso_time(stream_created, c->timestamp_created);
log_notice(LD_HEARTBEAT, " Stream#%d created at %s. "
"%s conn in state %s. "
"It is %slinked and %sreading from a linked connection %p. "
"Package window %d. "
"%s for close (%s:%d). Hold-open is %sset. "
"Has %ssent RELAY_END. %s on circuit.",
stream_num,
stream_created,
conn_type_to_string(c->type),
conn_state_to_string(c->type, c->state),
c->linked ? "" : "not ",
c->reading_from_linked_conn ? "": "not",
c->linked_conn,
conn->package_window,
c->marked_for_close ? "Marked" : "Not marked",
c->marked_for_close_file ? c->marked_for_close_file : "--",
c->marked_for_close,
c->hold_open_until_flushed ? "" : "not ",
conn->edge_has_sent_end ? "" : "not ",
conn->edge_blocked_on_circ ? "Blocked" : "Not blocked");
if (! c->linked_conn)
continue;
c = c->linked_conn;
log_notice(LD_HEARTBEAT, " Linked to %s connection in state %s "
"(Purpose %d). %s for close (%s:%d). Hold-open is %sset. ",
conn_type_to_string(c->type),
conn_state_to_string(c->type, c->state),
c->purpose,
c->marked_for_close ? "Marked" : "Not marked",
c->marked_for_close_file ? c->marked_for_close_file : "--",
c->marked_for_close,
c->hold_open_until_flushed ? "" : "not ");
}
} SMARTLIST_FOREACH_END(ocirc);
log_notice(LD_HEARTBEAT, "It has been %ld seconds since I last called "
"circuit_expire_old_circuits_clientside().",
(long)(now - last_expired_clientside_circuits));
done:
smartlist_free(log_these);
}
/** Remove any elements in <b>needed_ports</b> that are handled by an
* open or in-progress circuit.
*/
void
circuit_remove_handled_ports(smartlist_t *needed_ports)
{
int i;
uint16_t *port;
for (i = 0; i < smartlist_len(needed_ports); ++i) {
port = smartlist_get(needed_ports, i);
tor_assert(*port);
if (circuit_stream_is_being_handled(NULL, *port,
MIN_CIRCUITS_HANDLING_STREAM)) {
// log_debug(LD_CIRC,"Port %d is already being handled; removing.", port);
smartlist_del(needed_ports, i--);
tor_free(port);
} else {
log_debug(LD_CIRC,"Port %d is not handled.", *port);
}
}
}
/** Return 1 if at least <b>min</b> general-purpose non-internal circuits
* will have an acceptable exit node for exit stream <b>conn</b> if it
* is defined, else for "*:port".
* Else return 0.
*/
int
circuit_stream_is_being_handled(entry_connection_t *conn,
uint16_t port, int min)
{
const node_t *exitnode;
int num=0;
time_t now = time(NULL);
int need_uptime = smartlist_contains_int_as_string(
get_options()->LongLivedPorts,
conn ? conn->socks_request->port : port);
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (CIRCUIT_IS_ORIGIN(circ) &&
!circ->marked_for_close &&
circ->purpose == CIRCUIT_PURPOSE_C_GENERAL &&
(!circ->timestamp_dirty ||
circ->timestamp_dirty + get_options()->MaxCircuitDirtiness > now)) {
origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ);
cpath_build_state_t *build_state = origin_circ->build_state;
if (build_state->is_internal || build_state->onehop_tunnel)
continue;
if (origin_circ->unusable_for_new_conns)
continue;
exitnode = build_state_get_exit_node(build_state);
if (exitnode && (!need_uptime || build_state->need_uptime)) {
int ok;
if (conn) {
ok = connection_ap_can_use_exit(conn, exitnode);
} else {
addr_policy_result_t r;
r = compare_tor_addr_to_node_policy(NULL, port, exitnode);
ok = r != ADDR_POLICY_REJECTED && r != ADDR_POLICY_PROBABLY_REJECTED;
}
if (ok) {
if (++num >= min)
return 1;
}
}
}
}
SMARTLIST_FOREACH_END(circ);
return 0;
}
/** Don't keep more than this many unused open circuits around. */
#define MAX_UNUSED_OPEN_CIRCUITS 14
/* Return true if a circuit is available for use, meaning that it is open,
* clean, usable for new multi-hop connections, and a general purpose origin
* circuit.
* Accept any kind of circuit, return false if the above conditions are not
* met. */
STATIC int
circuit_is_available_for_use(const circuit_t *circ)
{
const origin_circuit_t *origin_circ;
cpath_build_state_t *build_state;
if (!CIRCUIT_IS_ORIGIN(circ))
return 0; /* We first filter out only origin circuits before doing the
following checks. */
if (circ->marked_for_close)
return 0; /* Don't mess with marked circs */
if (circ->timestamp_dirty)
return 0; /* Only count clean circs */
if (circ->purpose != CIRCUIT_PURPOSE_C_GENERAL)
return 0; /* We only pay attention to general purpose circuits.
General purpose circuits are always origin circuits. */
origin_circ = CONST_TO_ORIGIN_CIRCUIT(circ);
if (origin_circ->unusable_for_new_conns)
return 0;
build_state = origin_circ->build_state;
if (build_state->onehop_tunnel)
return 0;
return 1;
}
/* Return true if we need any more exit circuits.
* needs_uptime and needs_capacity are set only if we need more exit circuits.
* Check if we know of a port that's been requested recently and no circuit
* is currently available that can handle it. */
STATIC int
needs_exit_circuits(time_t now, int *needs_uptime, int *needs_capacity)
{
return (!circuit_all_predicted_ports_handled(now, needs_uptime,
needs_capacity) &&
router_have_consensus_path() == CONSENSUS_PATH_EXIT);
}
/* Hidden services need at least this many internal circuits */
#define SUFFICIENT_UPTIME_INTERNAL_HS_SERVERS 3
/* Return true if we need any more hidden service server circuits.
* HS servers only need an internal circuit. */
STATIC int
needs_hs_server_circuits(time_t now, int num_uptime_internal)
{
if (!rend_num_services() && !hs_service_get_num_services()) {
/* No services, we don't need anything. */
goto no_need;
}
if (num_uptime_internal >= SUFFICIENT_UPTIME_INTERNAL_HS_SERVERS) {
/* We have sufficient amount of internal circuit. */
goto no_need;
}
if (router_have_consensus_path() == CONSENSUS_PATH_UNKNOWN) {
/* Consensus hasn't been checked or might be invalid so requesting
* internal circuits is not wise. */
goto no_need;
}
/* At this point, we need a certain amount of circuits and we will most
* likely use them for rendezvous so we note down the use of internal
* circuit for our prediction for circuit needing uptime and capacity. */
rep_hist_note_used_internal(now, 1, 1);
return 1;
no_need:
return 0;
}
/* We need at least this many internal circuits for hidden service clients */
#define SUFFICIENT_INTERNAL_HS_CLIENTS 3
/* We need at least this much uptime for internal circuits for hidden service
* clients */
#define SUFFICIENT_UPTIME_INTERNAL_HS_CLIENTS 2
/* Return true if we need any more hidden service client circuits.
* HS clients only need an internal circuit. */
STATIC int
needs_hs_client_circuits(time_t now, int *needs_uptime, int *needs_capacity,
int num_internal, int num_uptime_internal)
{
int used_internal_recently = rep_hist_get_predicted_internal(now,
needs_uptime,
needs_capacity);
int requires_uptime = num_uptime_internal <
SUFFICIENT_UPTIME_INTERNAL_HS_CLIENTS &&
needs_uptime;
return (used_internal_recently &&
(requires_uptime || num_internal < SUFFICIENT_INTERNAL_HS_CLIENTS) &&
router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN);
}
/* The minimum number of open slots we should keep in order to preemptively
* build circuits. */
#define CBT_MIN_REMAINING_PREEMPTIVE_CIRCUITS 2
/* Check to see if we need more circuits to have a good build timeout. However,
* leave a couple slots open so that we can still build circuits preemptively
* as needed. */
#define CBT_MAX_UNUSED_OPEN_CIRCUITS (MAX_UNUSED_OPEN_CIRCUITS - \
CBT_MIN_REMAINING_PREEMPTIVE_CIRCUITS)
/* Return true if we need more circuits for a good build timeout.
* XXXX make the assumption that build timeout streams should be
* created whenever we can build internal circuits. */
STATIC int
needs_circuits_for_build(int num)
{
if (router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN) {
if (num < CBT_MAX_UNUSED_OPEN_CIRCUITS &&
!circuit_build_times_disabled(get_options()) &&
circuit_build_times_needs_circuits_now(get_circuit_build_times())) {
return 1;
}
}
return 0;
}
/** Determine how many circuits we have open that are clean,
* Make sure it's enough for all the upcoming behaviors we predict we'll have.
* But put an upper bound on the total number of circuits.
*/
static void
circuit_predict_and_launch_new(void)
{
int num=0, num_internal=0, num_uptime_internal=0;
int hidserv_needs_uptime=0, hidserv_needs_capacity=1;
int port_needs_uptime=0, port_needs_capacity=1;
time_t now = time(NULL);
int flags = 0;
/* Count how many of each type of circuit we currently have. */
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (!circuit_is_available_for_use(circ))
continue;
num++;
cpath_build_state_t *build_state = TO_ORIGIN_CIRCUIT(circ)->build_state;
if (build_state->is_internal)
num_internal++;
if (build_state->need_uptime && build_state->is_internal)
num_uptime_internal++;
}
SMARTLIST_FOREACH_END(circ);
/* If that's enough, then stop now. */
if (num >= MAX_UNUSED_OPEN_CIRCUITS)
return;
if (needs_exit_circuits(now, &port_needs_uptime, &port_needs_capacity)) {
if (port_needs_uptime)
flags |= CIRCLAUNCH_NEED_UPTIME;
if (port_needs_capacity)
flags |= CIRCLAUNCH_NEED_CAPACITY;
log_info(LD_CIRC,
"Have %d clean circs (%d internal), need another exit circ.",
num, num_internal);
circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags);
return;
}
if (needs_hs_server_circuits(now, num_uptime_internal)) {
flags = (CIRCLAUNCH_NEED_CAPACITY | CIRCLAUNCH_NEED_UPTIME |
CIRCLAUNCH_IS_INTERNAL);
log_info(LD_CIRC,
"Have %d clean circs (%d internal), need another internal "
"circ for my hidden service.",
num, num_internal);
circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags);
return;
}
if (needs_hs_client_circuits(now, &hidserv_needs_uptime,
&hidserv_needs_capacity,
num_internal, num_uptime_internal))
{
if (hidserv_needs_uptime)
flags |= CIRCLAUNCH_NEED_UPTIME;
if (hidserv_needs_capacity)
flags |= CIRCLAUNCH_NEED_CAPACITY;
flags |= CIRCLAUNCH_IS_INTERNAL;
log_info(LD_CIRC,
"Have %d clean circs (%d uptime-internal, %d internal), need"
" another hidden service circ.",
num, num_uptime_internal, num_internal);
circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags);
return;
}
if (needs_circuits_for_build(num)) {
flags = CIRCLAUNCH_NEED_CAPACITY;
/* if there are no exits in the consensus, make timeout
* circuits internal */
if (router_have_consensus_path() == CONSENSUS_PATH_INTERNAL)
flags |= CIRCLAUNCH_IS_INTERNAL;
log_info(LD_CIRC,
"Have %d clean circs need another buildtime test circ.", num);
circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, flags);
return;
}
}
/** Build a new test circuit every 5 minutes */
#define TESTING_CIRCUIT_INTERVAL 300
/** This function is called once a second, if router_have_minimum_dir_info()
* is true. 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)
{
const or_options_t *options = get_options();
/* launch a new circ for any pending streams that need one
* XXXX make the assumption that (some) AP streams (i.e. HS clients)
* don't require an exit circuit, review in #13814.
* This allows HSs to function in a consensus without exits. */
if (router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN)
connection_ap_rescan_and_attach_pending();
circuit_expire_old_circs_as_needed(now);
if (!options->DisablePredictedCircuits)
circuit_predict_and_launch_new();
}
/**
* Called once a second either directly or from
* circuit_build_needed_circs(). As appropriate (once per NewCircuitPeriod)
* resets failure counts and expires old circuits.
*/
void
circuit_expire_old_circs_as_needed(time_t now)
{
static time_t time_to_expire_and_reset = 0;
if (time_to_expire_and_reset < now) {
circuit_reset_failure_count(1);
time_to_expire_and_reset = now + get_options()->NewCircuitPeriod;
if (proxy_mode(get_options()))
addressmap_clean(now);
circuit_expire_old_circuits_clientside();
#if 0 /* disable for now, until predict-and-launch-new can cull leftovers */
/* If we ever re-enable, this has to move into
* circuit_build_needed_circs */
circ = circuit_get_youngest_clean_open(CIRCUIT_PURPOSE_C_GENERAL);
if (get_options()->RunTesting &&
circ &&
circ->timestamp_began.tv_sec + TESTING_CIRCUIT_INTERVAL < now) {
log_fn(LOG_INFO,"Creating a new testing circuit.");
circuit_launch(CIRCUIT_PURPOSE_C_GENERAL, 0);
}
#endif
}
}
/** 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, edge_connection_t *conn)
{
edge_connection_t *prevconn;
tor_assert(circ);
tor_assert(conn);
if (conn->base_.type == CONN_TYPE_AP) {
entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn);
entry_conn->may_use_optimistic_data = 0;
}
conn->cpath_layer = NULL; /* don't keep a stale pointer */
conn->on_circuit = NULL;
if (CIRCUIT_IS_ORIGIN(circ)) {
origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ);
int removed = 0;
if (conn == origin_circ->p_streams) {
origin_circ->p_streams = conn->next_stream;
removed = 1;
} else {
for (prevconn = origin_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;
removed = 1;
}
}
if (removed) {
log_debug(LD_APP, "Removing stream %d from circ %u",
conn->stream_id, (unsigned)circ->n_circ_id);
/* If the stream was removed, and it was a rend stream, decrement the
* number of streams on the circuit associated with the rend service.
*/
if (circ->purpose == CIRCUIT_PURPOSE_S_REND_JOINED) {
hs_dec_rdv_stream_counter(origin_circ);
}
return;
}
} else {
or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
if (conn == or_circ->n_streams) {
or_circ->n_streams = conn->next_stream;
return;
}
if (conn == or_circ->resolving_streams) {
or_circ->resolving_streams = conn->next_stream;
return;
}
for (prevconn = or_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 = or_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_warn(LD_BUG,"Edge connection not in circuit's list.");
/* Don't give an error here; it's harmless. */
tor_fragile_assert();
}
/** Find each circuit that has been unused for too long, or dirty
* for too long and has no streams on it: mark it for close.
*/
static void
circuit_expire_old_circuits_clientside(void)
{
struct timeval cutoff, now;
tor_gettimeofday(&now);
last_expired_clientside_circuits = now.tv_sec;
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (circ->marked_for_close || !CIRCUIT_IS_ORIGIN(circ))
continue;
cutoff = now;
cutoff.tv_sec -= TO_ORIGIN_CIRCUIT(circ)->circuit_idle_timeout;
/* 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 + get_options()->MaxCircuitDirtiness <
now.tv_sec &&
!TO_ORIGIN_CIRCUIT(circ)->p_streams /* nothing attached */ ) {
log_debug(LD_CIRC, "Closing n_circ_id %u (dirty %ld sec ago, "
"purpose %d)",
(unsigned)circ->n_circ_id,
(long)(now.tv_sec - circ->timestamp_dirty),
circ->purpose);
/* Don't do this magic for testing circuits. Their death is governed
* by circuit_expire_building */
if (circ->purpose != CIRCUIT_PURPOSE_PATH_BIAS_TESTING)
circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
} else if (!circ->timestamp_dirty && circ->state == CIRCUIT_STATE_OPEN) {
if (timercmp(&circ->timestamp_began, &cutoff, OP_LT)) {
if (circ->purpose == CIRCUIT_PURPOSE_C_GENERAL ||
circ->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT ||
circ->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO ||
circ->purpose == CIRCUIT_PURPOSE_TESTING ||
(circ->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING &&
circ->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) ||
circ->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) {
log_info(LD_CIRC,
"Closing circuit "U64_FORMAT
" that has been unused for %ld msec.",
U64_PRINTF_ARG(TO_ORIGIN_CIRCUIT(circ)->global_identifier),
tv_mdiff(&circ->timestamp_began, &now));
circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
} else if (!TO_ORIGIN_CIRCUIT(circ)->is_ancient) {
/* Server-side rend joined circuits can end up really old, because
* they are reused by clients for longer than normal. The client
* controls their lifespan. (They never become dirty, because
* connection_exit_begin_conn() never marks anything as dirty.)
* Similarly, server-side intro circuits last a long time. */
if (circ->purpose != CIRCUIT_PURPOSE_S_REND_JOINED &&
circ->purpose != CIRCUIT_PURPOSE_S_INTRO) {
log_notice(LD_CIRC,
"Ancient non-dirty circuit %d is still around after "
"%ld milliseconds. Purpose: %d (%s)",
TO_ORIGIN_CIRCUIT(circ)->global_identifier,
tv_mdiff(&circ->timestamp_began, &now),
circ->purpose,
circuit_purpose_to_string(circ->purpose));
TO_ORIGIN_CIRCUIT(circ)->is_ancient = 1;
}
}
}
}
} SMARTLIST_FOREACH_END(circ);
}
/** How long do we wait before killing circuits with the properties
* described below?
*
* Probably we could choose a number here as low as 5 to 10 seconds,
* since these circs are used for begindir, and a) generally you either
* ask another begindir question right after or you don't for a long time,
* b) clients at least through 0.2.1.x choose from the whole set of
* directory mirrors at each choice, and c) re-establishing a one-hop
* circuit via create-fast is a light operation assuming the TLS conn is
* still there.
*
* I expect "b" to go away one day when we move to using directory
* guards, but I think "a" and "c" are good enough reasons that a low
* number is safe even then.
*/
#define IDLE_ONE_HOP_CIRC_TIMEOUT 60
/** Find each non-origin circuit that has been unused for too long,
* has no streams on it, used a create_fast, and ends here: mark it
* for close.
*/
void
circuit_expire_old_circuits_serverside(time_t now)
{
or_circuit_t *or_circ;
time_t cutoff = now - IDLE_ONE_HOP_CIRC_TIMEOUT;
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (circ->marked_for_close || CIRCUIT_IS_ORIGIN(circ))
continue;
or_circ = TO_OR_CIRCUIT(circ);
/* If the circuit has been idle for too long, and there are no streams
* on it, and it ends here, and it used a create_fast, mark it for close.
*/
if (or_circ->is_first_hop && !circ->n_chan &&
!or_circ->n_streams && !or_circ->resolving_streams &&
or_circ->p_chan &&
channel_when_last_xmit(or_circ->p_chan) <= cutoff) {
log_info(LD_CIRC, "Closing circ_id %u (empty %d secs ago)",
(unsigned)or_circ->p_circ_id,
(int)(now - channel_when_last_xmit(or_circ->p_chan)));
circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
}
}
SMARTLIST_FOREACH_END(circ);
}
/** Number of testing circuits we want open before testing our bandwidth. */
#define NUM_PARALLEL_TESTING_CIRCS 4
/** True iff we've ever had enough testing circuits open to test our
* bandwidth. */
static int have_performed_bandwidth_test = 0;
/** Reset have_performed_bandwidth_test, so we'll start building
* testing circuits again so we can exercise our bandwidth. */
void
reset_bandwidth_test(void)
{
have_performed_bandwidth_test = 0;
}
/** Return 1 if we've already exercised our bandwidth, or if we
* have fewer than NUM_PARALLEL_TESTING_CIRCS testing circuits
* established or on the way. Else return 0.
*/
int
circuit_enough_testing_circs(void)
{
int num = 0;
if (have_performed_bandwidth_test)
return 1;
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (!circ->marked_for_close && CIRCUIT_IS_ORIGIN(circ) &&
circ->purpose == CIRCUIT_PURPOSE_TESTING &&
circ->state == CIRCUIT_STATE_OPEN)
num++;
}
SMARTLIST_FOREACH_END(circ);
return num >= NUM_PARALLEL_TESTING_CIRCS;
}
/** A testing circuit has completed. Take whatever stats we want.
* Noticing reachability is taken care of in onionskin_answer(),
* so there's no need to record anything here. But if we still want
* to do the bandwidth test, and we now have enough testing circuits
* open, do it.
*/
static void
circuit_testing_opened(origin_circuit_t *circ)
{
if (have_performed_bandwidth_test ||
!check_whether_orport_reachable(get_options())) {
/* either we've already done everything we want with testing circuits,
* or this testing circuit became open due to a fluke, e.g. we picked
* a last hop where we already had the connection open due to an
* outgoing local circuit. */
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_AT_ORIGIN);
} else if (circuit_enough_testing_circs()) {
router_perform_bandwidth_test(NUM_PARALLEL_TESTING_CIRCS, time(NULL));
have_performed_bandwidth_test = 1;
} else
consider_testing_reachability(1, 0);
}
/** A testing circuit has failed to build. Take whatever stats we want. */
static void
circuit_testing_failed(origin_circuit_t *circ, int at_last_hop)
{
const or_options_t *options = get_options();
if (server_mode(options) && check_whether_orport_reachable(options))
return;
log_info(LD_GENERAL,
"Our testing circuit (to see if your ORPort is reachable) "
"has failed. I'll try again later.");
/* These aren't used yet. */
(void)circ;
(void)at_last_hop;
}
/** 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(origin_circuit_t *circ)
{
control_event_circuit_status(circ, CIRC_EVENT_BUILT, 0);
/* Remember that this circuit has finished building. Now if we start
* it building again later (e.g. by extending it), we will know not
* to consider its build time. */
circ->has_opened = 1;
switch (TO_CIRCUIT(circ)->purpose) {
case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
rend_client_rendcirc_has_opened(circ);
/* Start building an intro circ if we don't have one yet. */
connection_ap_attach_pending(1);
/* This isn't a call to circuit_try_attaching_streams because a
* circuit in _C_ESTABLISH_REND state isn't connected to its
* hidden service yet, thus we can't attach streams to it yet,
* thus circuit_try_attaching_streams would always clear the
* circuit's isolation state. circuit_try_attaching_streams is
* called later, when the rend circ enters _C_REND_JOINED
* state. */
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. */
circuit_try_attaching_streams(circ);
break;
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
/* at the service, waiting for introductions */
hs_service_circuit_has_opened(circ);
break;
case CIRCUIT_PURPOSE_S_CONNECT_REND:
/* at the service, connecting to rend point */
hs_service_circuit_has_opened(circ);
break;
case CIRCUIT_PURPOSE_TESTING:
circuit_testing_opened(circ);
break;
/* default:
* This won't happen in normal operation, but might happen if the
* controller did it. Just let it slide. */
}
}
/** If the stream-isolation state of <b>circ</b> can be cleared, clear
* it. Return non-zero iff <b>circ</b>'s isolation state was cleared. */
static int
circuit_try_clearing_isolation_state(origin_circuit_t *circ)
{
if (/* The circuit may have become non-open if it was cannibalized.*/
circ->base_.state == CIRCUIT_STATE_OPEN &&
/* If !isolation_values_set, there is nothing to clear. */
circ->isolation_values_set &&
/* It's not legal to clear a circuit's isolation info if it's ever had
* streams attached */
!circ->isolation_any_streams_attached) {
/* If we have any isolation information set on this circuit, and
* we didn't manage to attach any streams to it, then we can
* and should clear it and try again. */
circuit_clear_isolation(circ);
return 1;
} else {
return 0;
}
}
/** Called when a circuit becomes ready for streams to be attached to
* it. */
void
circuit_try_attaching_streams(origin_circuit_t *circ)
{
/* Attach streams to this circuit if we can. */
connection_ap_attach_pending(1);
/* The call to circuit_try_clearing_isolation_state here will do
* nothing and return 0 if we didn't attach any streams to circ
* above. */
if (circuit_try_clearing_isolation_state(circ)) {
/* Maybe *now* we can attach some streams to this circuit. */
connection_ap_attach_pending(1);
}
}
/** Called whenever a circuit could not be successfully built.
*/
void
circuit_build_failed(origin_circuit_t *circ)
{
channel_t *n_chan = NULL;
/* 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;
}
if (circ->cpath &&
circ->cpath->state != CPATH_STATE_OPEN &&
! circ->base_.received_destroy) {
/* We failed at the first hop for some reason other than a DESTROY cell.
* If there's an OR connection to blame, blame it. Also, avoid this relay
* for a while, and fail any one-hop directory fetches destined for it. */
const char *n_chan_id = circ->cpath->extend_info->identity_digest;
int already_marked = 0;
if (circ->base_.n_chan) {
n_chan = circ->base_.n_chan;
if (n_chan->is_bad_for_new_circs) {
/* We only want to blame this router when a fresh healthy
* connection fails. So don't mark this router as newly failed,
* since maybe this was just an old circuit attempt that's
* finally timing out now. Also, there's no need to blow away
* circuits/streams/etc, since the failure of an unhealthy conn
* doesn't tell us much about whether a healthy conn would
* succeed. */
already_marked = 1;
}
log_info(LD_OR,
"Our circuit failed to get a response from the first hop "
"(%s). I'm going to try to rotate to a better connection.",
channel_get_canonical_remote_descr(n_chan));
n_chan->is_bad_for_new_circs = 1;
} else {
log_info(LD_OR,
"Our circuit died before the first hop with no connection");
}
if (n_chan_id && !already_marked) {
/* New guard API: we failed. */
if (circ->guard_state)
entry_guard_failed(&circ->guard_state);
/* if there are any one-hop streams waiting on this circuit, fail
* them now so they can retry elsewhere. */
connection_ap_fail_onehop(n_chan_id, circ->build_state);
}
}
switch (circ->base_.purpose) {
case CIRCUIT_PURPOSE_C_GENERAL:
/* If we never built the circuit, note it as a failure. */
circuit_increment_failure_count();
if (failed_at_last_hop) {
/* Make sure any streams that demand our last hop as their exit
* know that it's unlikely to happen. */
circuit_discard_optional_exit_enclaves(circ->cpath->prev->extend_info);
}
break;
case CIRCUIT_PURPOSE_TESTING:
circuit_testing_failed(circ, failed_at_last_hop);
break;
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
/* at the service, waiting for introductions */
if (circ->base_.state != CIRCUIT_STATE_OPEN) {
circuit_increment_failure_count();
}
/* no need to care here, because the service will rebuild intro
* points periodically. */
break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* at the client, connecting to intro point */
/* Don't increment failure count, since the service may have picked
* the introduction point maliciously */
/* The client 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 the client, waiting for the service */
circuit_increment_failure_count();
/* the client 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 the service, connecting to rend point */
/* Don't increment failure count, since the client may have picked
* the rendezvous point maliciously */
log_info(LD_REND,
"Couldn't connect to the client's chosen rend point %s "
"(%s hop failed).",
escaped(build_state_get_exit_nickname(circ->build_state)),
failed_at_last_hop?"last":"non-last");
hs_circ_retry_service_rendezvous_point(circ);
break;
/* default:
* This won't happen in normal operation, but might happen if the
* controller did it. Just let it slide. */
}
}
/** Number of consecutive failures so far; should only be touched by
* circuit_launch_new and circuit_*_failure_count.
*/
static int n_circuit_failures = 0;
/** Before the last time we called circuit_reset_failure_count(), were
* there a lot of failures? */
static int did_circs_fail_last_period = 0;
/** Don't retry launching a new circuit if we try this many times with no
* success. */
#define MAX_CIRCUIT_FAILURES 5
/** Launch a new circuit; see circuit_launch_by_extend_info() for
* details on arguments. */
origin_circuit_t *
circuit_launch(uint8_t purpose, int flags)
{
return circuit_launch_by_extend_info(purpose, NULL, flags);
}
/* Do we have enough descriptors to build paths?
* If need_exit is true, return 1 if we can build exit paths.
* (We need at least one Exit in the consensus to build exit paths.)
* If need_exit is false, return 1 if we can build internal paths.
*/
static int
have_enough_path_info(int need_exit)
{
if (need_exit)
return router_have_consensus_path() == CONSENSUS_PATH_EXIT;
else
return router_have_consensus_path() != CONSENSUS_PATH_UNKNOWN;
}
/** Launch a new circuit with purpose <b>purpose</b> and exit node
* <b>extend_info</b> (or NULL to select a random exit node). If flags
* contains CIRCLAUNCH_NEED_UPTIME, choose among routers with high uptime. If
* CIRCLAUNCH_NEED_CAPACITY is set, choose among routers with high bandwidth.
* If CIRCLAUNCH_IS_INTERNAL is true, the last hop need not be an exit node.
* If CIRCLAUNCH_ONEHOP_TUNNEL is set, the circuit will have only one hop.
* Return the newly allocated circuit on success, or NULL on failure. */
origin_circuit_t *
circuit_launch_by_extend_info(uint8_t purpose,
extend_info_t *extend_info,
int flags)
{
origin_circuit_t *circ;
int onehop_tunnel = (flags & CIRCLAUNCH_ONEHOP_TUNNEL) != 0;
int have_path = have_enough_path_info(! (flags & CIRCLAUNCH_IS_INTERNAL) );
int need_specific_rp = 0;
if (!onehop_tunnel && (!router_have_minimum_dir_info() || !have_path)) {
log_debug(LD_CIRC,"Haven't %s yet; canceling "
"circuit launch.",
!router_have_minimum_dir_info() ?
"fetched enough directory info" :
"received a consensus with exits");
return NULL;
}
/* If Tor2webRendezvousPoints is enabled and we are dealing with an
RP circuit, we want a specific RP node so we shouldn't canibalize
an already existing circuit. */
if (get_options()->Tor2webRendezvousPoints &&
purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND) {
need_specific_rp = 1;
}
if ((extend_info || purpose != CIRCUIT_PURPOSE_C_GENERAL) &&
purpose != CIRCUIT_PURPOSE_TESTING &&
!onehop_tunnel && !need_specific_rp) {
/* see if there are appropriate circs available to cannibalize. */
/* XXX if we're planning to add a hop, perhaps we want to look for
* internal circs rather than exit circs? -RD */
circ = circuit_find_to_cannibalize(purpose, extend_info, flags);
if (circ) {
uint8_t old_purpose = circ->base_.purpose;
struct timeval old_timestamp_began = circ->base_.timestamp_began;
log_info(LD_CIRC,"Cannibalizing circ '%s' for purpose %d (%s)",
build_state_get_exit_nickname(circ->build_state), purpose,
circuit_purpose_to_string(purpose));
if ((purpose == CIRCUIT_PURPOSE_S_CONNECT_REND ||
purpose == CIRCUIT_PURPOSE_C_INTRODUCING) &&
circ->path_state == PATH_STATE_BUILD_SUCCEEDED) {
/* Path bias: Cannibalized rends pre-emptively count as a
* successfully built but unused closed circuit. We don't
* wait until the extend (or the close) because the rend
* point could be malicious.
*
* Same deal goes for client side introductions. Clients
* can be manipulated to connect repeatedly to them
* (especially web clients).
*
* If we decide to probe the initial portion of these circs,
* (up to the adversary's final hop), we need to remove this,
* or somehow mark the circuit with a special path state.
*/
/* This must be called before the purpose change */
pathbias_check_close(circ, END_CIRC_REASON_FINISHED);
}
circuit_change_purpose(TO_CIRCUIT(circ), purpose);
/* Reset the start date of this circ, else expire_building
* will see it and think it's been trying to build since it
* began.
*
* Technically, the code should reset this when the
* create cell is finally sent, but we're close enough
* here. */
tor_gettimeofday(&circ->base_.timestamp_began);
control_event_circuit_cannibalized(circ, old_purpose,
&old_timestamp_began);
switch (purpose) {
case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
/* it's ready right now */
break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
case CIRCUIT_PURPOSE_S_CONNECT_REND:
case CIRCUIT_PURPOSE_C_GENERAL:
case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
/* need to add a new hop */
tor_assert(extend_info);
if (circuit_extend_to_new_exit(circ, extend_info) < 0)
return NULL;
break;
default:
log_warn(LD_BUG,
"unexpected purpose %d when cannibalizing a circ.",
purpose);
tor_fragile_assert();
return NULL;
}
return circ;
}
}
if (did_circs_fail_last_period &&
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, extend_info, flags);
}
/** 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_debug(LD_CIRC,"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(int timeout)
{
if (timeout && n_circuit_failures > MAX_CIRCUIT_FAILURES)
did_circs_fail_last_period = 1;
else
did_circs_fail_last_period = 0;
n_circuit_failures = 0;
}
/** Find an open circ that we're happy to use for <b>conn</b> and 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(entry_connection_t *conn,
uint8_t desired_circuit_purpose,
origin_circuit_t **circp)
{
origin_circuit_t *circ;
int check_exit_policy;
int need_uptime, need_internal;
int want_onehop;
const or_options_t *options = get_options();
tor_assert(conn);
tor_assert(circp);
if (ENTRY_TO_CONN(conn)->state != AP_CONN_STATE_CIRCUIT_WAIT) {
connection_t *c = ENTRY_TO_CONN(conn);
log_err(LD_BUG, "Connection state mismatch: wanted "
"AP_CONN_STATE_CIRCUIT_WAIT, but got %d (%s)",
c->state, conn_state_to_string(c->type, c->state));
}
tor_assert(ENTRY_TO_CONN(conn)->state == AP_CONN_STATE_CIRCUIT_WAIT);
/* Will the exit policy of the exit node apply to this stream? */
check_exit_policy =
conn->socks_request->command == SOCKS_COMMAND_CONNECT &&
!conn->use_begindir &&
!connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn));
/* Does this connection want a one-hop circuit? */
want_onehop = conn->want_onehop;
/* Do we need a high-uptime circuit? */
need_uptime = !conn->want_onehop && !conn->use_begindir &&
smartlist_contains_int_as_string(options->LongLivedPorts,
conn->socks_request->port);
/* Do we need an "internal" circuit? */
if (desired_circuit_purpose != CIRCUIT_PURPOSE_C_GENERAL)
need_internal = 1;
else if (conn->use_begindir || conn->want_onehop)
need_internal = 1;
else
need_internal = 0;
/* We now know what kind of circuit we need. See if there is an
* open circuit that we can use for this stream */
circ = circuit_get_best(conn, 1 /* Insist on open circuits */,
desired_circuit_purpose,
need_uptime, need_internal);
if (circ) {
/* We got a circuit that will work for this stream! We can return it. */
*circp = circ;
return 1; /* we're happy */
}
/* Okay, there's no circuit open that will work for this stream. Let's
* see if there's an in-progress circuit or if we have to launch one */
/* Do we know enough directory info to build circuits at all? */
int have_path = have_enough_path_info(!need_internal);
if (!want_onehop && (!router_have_minimum_dir_info() || !have_path)) {
/* If we don't have enough directory information, we can't build
* multihop circuits.
*/
if (!connection_get_by_type(CONN_TYPE_DIR)) {
int severity = LOG_NOTICE;
/* Retry some stuff that might help the connection work. */
if (entry_list_is_constrained(options) &&
guards_retry_optimistic(options)) {
log_fn(severity, LD_APP|LD_DIR,
"Application request when we haven't %s. "
"Optimistically trying known %s again.",
!router_have_minimum_dir_info() ?
"used client functionality lately" :
"received a consensus with exits",
options->UseBridges ? "bridges" : "entrynodes");
} else if (!options->UseBridges || any_bridge_descriptors_known()) {
log_fn(severity, LD_APP|LD_DIR,
"Application request when we haven't %s. "
"Optimistically trying directory fetches again.",
!router_have_minimum_dir_info() ?
"used client functionality lately" :
"received a consensus with exits");
routerlist_retry_directory_downloads(time(NULL));
}
}
/* Since we didn't have enough directory info, we can't attach now. The
* stream will be dealt with when router_have_minimum_dir_info becomes 1,
* or when all directory attempts fail and directory_all_unreachable()
* kills it.
*/
return 0;
}
/* Check whether the exit policy of the chosen exit, or the exit policies
* of _all_ nodes, would forbid this node. */
if (check_exit_policy) {
if (!conn->chosen_exit_name) {
struct in_addr in;
tor_addr_t addr, *addrp=NULL;
if (tor_inet_aton(conn->socks_request->address, &in)) {
tor_addr_from_in(&addr, &in);
addrp = &addr;
}
if (router_exit_policy_all_nodes_reject(addrp,
conn->socks_request->port,
need_uptime)) {
log_notice(LD_APP,
"No Tor server allows exit to %s:%d. Rejecting.",
safe_str_client(conn->socks_request->address),
conn->socks_request->port);
return -1;
}
} else {
/* XXXX Duplicates checks in connection_ap_handshake_attach_circuit:
* refactor into a single function. */
const node_t *node = node_get_by_nickname(conn->chosen_exit_name, 1);
int opt = conn->chosen_exit_optional;
if (node && !connection_ap_can_use_exit(conn, node)) {
log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP,
"Requested exit point '%s' is excluded or "
"would refuse request. %s.",
conn->chosen_exit_name, opt ? "Trying others" : "Closing");
if (opt) {
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name);
/* Try again. */
return circuit_get_open_circ_or_launch(conn,
desired_circuit_purpose,
circp);
}
return -1;
}
}
}
/* Now, check whether there already a circuit on the way that could handle
* this stream. This check matches the one above, but this time we
* do not require that the circuit will work. */
circ = circuit_get_best(conn, 0 /* don't insist on open circuits */,
desired_circuit_purpose,
need_uptime, need_internal);
if (circ)
log_debug(LD_CIRC, "one on the way!");
if (!circ) {
/* No open or in-progress circuit could handle this stream! We
* will have to launch one!
*/
/* The chosen exit node, if there is one. */
extend_info_t *extend_info=NULL;
const int n_pending = count_pending_general_client_circuits();
/* Do we have too many pending circuits? */
if (n_pending >= options->MaxClientCircuitsPending) {
static ratelim_t delay_limit = RATELIM_INIT(10*60);
char *m;
if ((m = rate_limit_log(&delay_limit, approx_time()))) {
log_notice(LD_APP, "We'd like to launch a circuit to handle a "
"connection, but we already have %d general-purpose client "
"circuits pending. Waiting until some finish.%s",
n_pending, m);
tor_free(m);
}
return 0;
}
/* If this is a hidden service trying to start an introduction point,
* handle that case. */
if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
/* need to pick an intro point */
rend_data_t *rend_data = ENTRY_TO_EDGE_CONN(conn)->rend_data;
tor_assert(rend_data);
extend_info = rend_client_get_random_intro(rend_data);
if (!extend_info) {
log_info(LD_REND,
"No intro points for '%s': re-fetching service descriptor.",
safe_str_client(rend_data_get_address(rend_data)));
rend_client_refetch_v2_renddesc(rend_data);
connection_ap_mark_as_non_pending_circuit(conn);
ENTRY_TO_CONN(conn)->state = AP_CONN_STATE_RENDDESC_WAIT;
return 0;
}
log_info(LD_REND,"Chose %s as intro point for '%s'.",
extend_info_describe(extend_info),
safe_str_client(rend_data_get_address(rend_data)));
}
/* If we have specified a particular exit node for our
* connection, then be sure to open a circuit to that exit node.
*/
if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_GENERAL) {
if (conn->chosen_exit_name) {
const node_t *r;
int opt = conn->chosen_exit_optional;
r = node_get_by_nickname(conn->chosen_exit_name, 1);
if (r && node_has_descriptor(r)) {
/* We might want to connect to an IPv6 bridge for loading
descriptors so we use the preferred address rather than
the primary. */
extend_info = extend_info_from_node(r, conn->want_onehop ? 1 : 0);
if (!extend_info) {
log_warn(LD_CIRC,"Could not make a one-hop connection to %s. "
"Discarding this circuit.", conn->chosen_exit_name);
return -1;
}
} else { /* ! (r && node_has_descriptor(r)) */
log_debug(LD_DIR, "considering %d, %s",
want_onehop, conn->chosen_exit_name);
if (want_onehop && conn->chosen_exit_name[0] == '$') {
/* We're asking for a one-hop circuit to a router that
* we don't have a routerinfo about. Make up an extend_info. */
/* XXX prop220: we need to make chosen_exit_name able to
* encode both key formats. This is not absolutely critical
* since this is just for one-hop circuits, but we should
* still get it done */
char digest[DIGEST_LEN];
char *hexdigest = conn->chosen_exit_name+1;
tor_addr_t addr;
if (strlen(hexdigest) < HEX_DIGEST_LEN ||
base16_decode(digest,DIGEST_LEN,
hexdigest,HEX_DIGEST_LEN) != DIGEST_LEN) {
log_info(LD_DIR, "Broken exit digest on tunnel conn. Closing.");
return -1;
}
if (tor_addr_parse(&addr, conn->socks_request->address) < 0) {
log_info(LD_DIR, "Broken address %s on tunnel conn. Closing.",
escaped_safe_str_client(conn->socks_request->address));
return -1;
}
/* XXXX prop220 add a workaround for ed25519 ID below*/
extend_info = extend_info_new(conn->chosen_exit_name+1,
digest,
NULL, /* Ed25519 ID */
NULL, NULL, /* onion keys */
&addr, conn->socks_request->port);
} else { /* ! (want_onehop && conn->chosen_exit_name[0] == '$') */
/* We will need an onion key for the router, and we
* don't have one. Refuse or relax requirements. */
log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP,
"Requested exit point '%s' is not known. %s.",
conn->chosen_exit_name, opt ? "Trying others" : "Closing");
if (opt) {
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name);
/* Try again with no requested exit */
return circuit_get_open_circ_or_launch(conn,
desired_circuit_purpose,
circp);
}
return -1;
}
}
}
} /* Done checking for general circutis with chosen exits. */
/* What purpose do we need to launch this circuit with? */
uint8_t new_circ_purpose;
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;
#ifdef ENABLE_TOR2WEB_MODE
/* If tor2Web is on, then hidden service requests should be one-hop.
*/
if (options->Tor2webMode &&
(new_circ_purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND ||
new_circ_purpose == CIRCUIT_PURPOSE_C_INTRODUCING)) {
want_onehop = 1;
}
#endif
/* Determine what kind of a circuit to launch, and actually launch it. */
{
int flags = CIRCLAUNCH_NEED_CAPACITY;
if (want_onehop) flags |= CIRCLAUNCH_ONEHOP_TUNNEL;
if (need_uptime) flags |= CIRCLAUNCH_NEED_UPTIME;
if (need_internal) flags |= CIRCLAUNCH_IS_INTERNAL;
circ = circuit_launch_by_extend_info(new_circ_purpose, extend_info,
flags);
}
extend_info_free(extend_info);
/* Now trigger things that need to happen when we launch circuits */
if (desired_circuit_purpose == CIRCUIT_PURPOSE_C_GENERAL) {
/* We just caused a circuit to get built because of this stream.
* If this stream has caused a _lot_ of circuits to be built, that's
* a bad sign: we should tell the user. */
if (conn->num_circuits_launched < NUM_CIRCUITS_LAUNCHED_THRESHOLD &&
++conn->num_circuits_launched == NUM_CIRCUITS_LAUNCHED_THRESHOLD)
log_info(LD_CIRC, "The application request to %s:%d has launched "
"%d circuits without finding one it likes.",
escaped_safe_str_client(conn->socks_request->address),
conn->socks_request->port,
conn->num_circuits_launched);
} else {
/* help predict this next time */
rep_hist_note_used_internal(time(NULL), need_uptime, 1);
if (circ) {
/* write the service_id into circ */
circ->rend_data = rend_data_dup(ENTRY_TO_EDGE_CONN(conn)->rend_data);
if (circ->base_.purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND &&
circ->base_.state == CIRCUIT_STATE_OPEN)
circuit_has_opened(circ);
}
}
} /* endif (!circ) */
/* We either found a good circuit, or launched a new circuit, or failed to
* do so. Report success, and delay. */
if (circ) {
/* Mark the circuit with the isolation fields for this connection.
* When the circuit arrives, we'll clear these flags: this is
* just some internal bookkeeping to make sure that we have
* launched enough circuits.
*/
connection_edge_update_circuit_isolation(conn, circ, 0);
} else {
log_info(LD_APP,
"No safe circuit (purpose %d) ready for edge "
"connection; delaying.",
desired_circuit_purpose);
}
*circp = circ;
return 0;
}
/** Return true iff <b>crypt_path</b> is one of the crypt_paths for
* <b>circ</b>. */
static int
cpath_is_on_circuit(origin_circuit_t *circ, crypt_path_t *crypt_path)
{
crypt_path_t *cpath, *cpath_next = NULL;
for (cpath = circ->cpath; cpath_next != circ->cpath; cpath = cpath_next) {
cpath_next = cpath->next;
if (crypt_path == cpath)
return 1;
}
return 0;
}
/** Return true iff client-side optimistic data is supported. */
static int
optimistic_data_enabled(void)
{
const or_options_t *options = get_options();
if (options->OptimisticData < 0) {
/* Note: this default was 0 before #18815 was merged. We can't take the
* parameter out of the consensus until versions before that are all
* obsolete. */
const int32_t enabled =
networkstatus_get_param(NULL, "UseOptimisticData", /*default*/ 1, 0, 1);
return (int)enabled;
}
return options->OptimisticData;
}
/** Attach the AP stream <b>apconn</b> to circ's linked list of
* p_streams. Also set apconn's cpath_layer to <b>cpath</b>, or to the last
* hop in circ's cpath if <b>cpath</b> is NULL.
*/
static void
link_apconn_to_circ(entry_connection_t *apconn, origin_circuit_t *circ,
crypt_path_t *cpath)
{
const node_t *exitnode = NULL;
/* add it into the linked list of streams on this circuit */
log_debug(LD_APP|LD_CIRC, "attaching new conn to circ. n_circ_id %u.",
(unsigned)circ->base_.n_circ_id);
/* reset it, so we can measure circ timeouts */
ENTRY_TO_CONN(apconn)->timestamp_lastread = time(NULL);
ENTRY_TO_EDGE_CONN(apconn)->next_stream = circ->p_streams;
ENTRY_TO_EDGE_CONN(apconn)->on_circuit = TO_CIRCUIT(circ);
/* assert_connection_ok(conn, time(NULL)); */
circ->p_streams = ENTRY_TO_EDGE_CONN(apconn);
if (connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(apconn))) {
/* We are attaching a stream to a rendezvous circuit. That means
* that an attempt to connect to a hidden service just
* succeeded. Tell rendclient.c. */
hs_client_note_connection_attempt_succeeded(ENTRY_TO_EDGE_CONN(apconn));
}
if (cpath) { /* we were given one; use it */
tor_assert(cpath_is_on_circuit(circ, cpath));
} else {
/* use the last hop in the circuit */
tor_assert(circ->cpath);
tor_assert(circ->cpath->prev);
tor_assert(circ->cpath->prev->state == CPATH_STATE_OPEN);
cpath = circ->cpath->prev;
}
ENTRY_TO_EDGE_CONN(apconn)->cpath_layer = cpath;
circ->isolation_any_streams_attached = 1;
connection_edge_update_circuit_isolation(apconn, circ, 0);
/* Compute the exitnode if possible, for logging below */
if (cpath->extend_info)
exitnode = node_get_by_id(cpath->extend_info->identity_digest);
/* See if we can use optimistic data on this circuit */
if (optimistic_data_enabled() &&
(circ->base_.purpose == CIRCUIT_PURPOSE_C_GENERAL ||
circ->base_.purpose == CIRCUIT_PURPOSE_C_REND_JOINED))
apconn->may_use_optimistic_data = 1;
else
apconn->may_use_optimistic_data = 0;
log_info(LD_APP, "Looks like completed circuit to %s %s allow "
"optimistic data for connection to %s",
circ->base_.purpose == CIRCUIT_PURPOSE_C_GENERAL ?
/* node_describe() does the right thing if exitnode is NULL */
safe_str_client(node_describe(exitnode)) :
"hidden service",
apconn->may_use_optimistic_data ? "does" : "doesn't",
safe_str_client(apconn->socks_request->address));
}
/** Return true iff <b>address</b> is matched by one of the entries in
* TrackHostExits. */
int
hostname_in_track_host_exits(const or_options_t *options, const char *address)
{
if (!options->TrackHostExits)
return 0;
SMARTLIST_FOREACH_BEGIN(options->TrackHostExits, const char *, cp) {
if (cp[0] == '.') { /* match end */
if (cp[1] == '\0' ||
!strcasecmpend(address, cp) ||
!strcasecmp(address, &cp[1]))
return 1;
} else if (strcasecmp(cp, address) == 0) {
return 1;
}
} SMARTLIST_FOREACH_END(cp);
return 0;
}
/** If an exit wasn't explicitly specified for <b>conn</b>, consider saving
* the exit that we *did* choose for use by future connections to
* <b>conn</b>'s destination.
*/
static void
consider_recording_trackhost(const entry_connection_t *conn,
const origin_circuit_t *circ)
{
const or_options_t *options = get_options();
char *new_address = NULL;
char fp[HEX_DIGEST_LEN+1];
/* Search the addressmap for this conn's destination. */
/* If they're not in the address map.. */
if (!options->TrackHostExits ||
addressmap_have_mapping(conn->socks_request->address,
options->TrackHostExitsExpire))
return; /* nothing to track, or already mapped */
if (!hostname_in_track_host_exits(options, conn->socks_request->address) ||
!circ->build_state->chosen_exit)
return;
/* write down the fingerprint of the chosen exit, not the nickname,
* because the chosen exit might not be named. */
base16_encode(fp, sizeof(fp),
circ->build_state->chosen_exit->identity_digest, DIGEST_LEN);
/* Add this exit/hostname pair to the addressmap. */
tor_asprintf(&new_address, "%s.%s.exit",
conn->socks_request->address, fp);
addressmap_register(conn->socks_request->address, new_address,
time(NULL) + options->TrackHostExitsExpire,
ADDRMAPSRC_TRACKEXIT, 0, 0);
}
/** Attempt to attach the connection <b>conn</b> to <b>circ</b>, and send a
* begin or resolve cell as appropriate. Return values are as for
* connection_ap_handshake_attach_circuit. The stream will exit from the hop
* indicated by <b>cpath</b>, or from the last hop in circ's cpath if
* <b>cpath</b> is NULL. */
int
connection_ap_handshake_attach_chosen_circuit(entry_connection_t *conn,
origin_circuit_t *circ,
crypt_path_t *cpath)
{
connection_t *base_conn = ENTRY_TO_CONN(conn);
tor_assert(conn);
tor_assert(base_conn->state == AP_CONN_STATE_CIRCUIT_WAIT ||
base_conn->state == AP_CONN_STATE_CONTROLLER_WAIT);
tor_assert(conn->socks_request);
tor_assert(circ);
tor_assert(circ->base_.state == CIRCUIT_STATE_OPEN);
base_conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
if (!circ->base_.timestamp_dirty ||
((conn->entry_cfg.isolation_flags & ISO_SOCKSAUTH) &&
(conn->entry_cfg.socks_iso_keep_alive) &&
(conn->socks_request->usernamelen ||
conn->socks_request->passwordlen))) {
/* When stream isolation is in use and controlled by an application
* we are willing to keep using the stream. */
circ->base_.timestamp_dirty = approx_time();
}
pathbias_count_use_attempt(circ);
/* Now, actually link the connection. */
link_apconn_to_circ(conn, circ, cpath);
tor_assert(conn->socks_request);
if (conn->socks_request->command == SOCKS_COMMAND_CONNECT) {
if (!conn->use_begindir)
consider_recording_trackhost(conn, circ);
if (connection_ap_handshake_send_begin(conn) < 0)
return -1;
} else {
if (connection_ap_handshake_send_resolve(conn) < 0)
return -1;
}
return 1;
}
/** Try to find a safe live circuit for stream <b>conn</b>. If we find one,
* attach the stream, send appropriate cells, and return 1. Otherwise,
* try to launch new circuit(s) for the stream. If we can launch
* circuits, return 0. Otherwise, if we simply can't proceed with
* this stream, return -1. (conn needs to die, and is maybe already marked).
*/
/* XXXX this function should mark for close whenever it returns -1;
* its callers shouldn't have to worry about that. */
int
connection_ap_handshake_attach_circuit(entry_connection_t *conn)
{
connection_t *base_conn = ENTRY_TO_CONN(conn);
int retval;
int conn_age;
int want_onehop;
tor_assert(conn);
tor_assert(base_conn->state == AP_CONN_STATE_CIRCUIT_WAIT);
tor_assert(conn->socks_request);
want_onehop = conn->want_onehop;
conn_age = (int)(time(NULL) - base_conn->timestamp_created);
/* Is this connection so old that we should give up on it? */
if (conn_age >= get_options()->SocksTimeout) {
int severity = (tor_addr_is_null(&base_conn->addr) && !base_conn->port) ?
LOG_INFO : LOG_NOTICE;
log_fn(severity, LD_APP,
"Tried for %d seconds to get a connection to %s:%d. Giving up.",
conn_age, safe_str_client(conn->socks_request->address),
conn->socks_request->port);
return -1;
}
/* We handle "general" (non-onion) connections much more straightforwardly.
*/
if (!connection_edge_is_rendezvous_stream(ENTRY_TO_EDGE_CONN(conn))) {
/* we're a general conn */
origin_circuit_t *circ=NULL;
/* Are we linked to a dir conn that aims to fetch a consensus?
* We check here because the conn might no longer be needed. */
if (base_conn->linked_conn &&
base_conn->linked_conn->type == CONN_TYPE_DIR &&
base_conn->linked_conn->purpose == DIR_PURPOSE_FETCH_CONSENSUS) {
/* Yes we are. Is there a consensus fetch farther along than us? */
if (networkstatus_consensus_is_already_downloading(
TO_DIR_CONN(base_conn->linked_conn)->requested_resource)) {
/* We're doing the "multiple consensus fetch attempts" game from
* proposal 210, and we're late to the party. Just close this conn.
* The circuit and TLS conn that we made will time out after a while
* if nothing else wants to use them. */
log_info(LD_DIR, "Closing extra consensus fetch (to %s) since one "
"is already downloading.", base_conn->linked_conn->address);
return -1;
}
}
/* If we have a chosen exit, we need to use a circuit that's
* open to that exit. See what exit we meant, and whether we can use it.
*/
if (conn->chosen_exit_name) {
const node_t *node = node_get_by_nickname(conn->chosen_exit_name, 1);
int opt = conn->chosen_exit_optional;
if (!node && !want_onehop) {
/* We ran into this warning when trying to extend a circuit to a
* hidden service directory for which we didn't have a router
* descriptor. See flyspray task 767 for more details. We should
* keep this in mind when deciding to use BEGIN_DIR cells for other
* directory requests as well. -KL*/
log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP,
"Requested exit point '%s' is not known. %s.",
conn->chosen_exit_name, opt ? "Trying others" : "Closing");
if (opt) {
/* If we are allowed to ignore the .exit request, do so */
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name);
return 0;
}
return -1;
}
if (node && !connection_ap_can_use_exit(conn, node)) {
log_fn(opt ? LOG_INFO : LOG_WARN, LD_APP,
"Requested exit point '%s' is excluded or "
"would refuse request. %s.",
conn->chosen_exit_name, opt ? "Trying others" : "Closing");
if (opt) {
/* If we are allowed to ignore the .exit request, do so */
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name);
return 0;
}
return -1;
}
}
/* Find the circuit that we should use, if there is one. Otherwise
* launch it. */
retval = circuit_get_open_circ_or_launch(
conn, CIRCUIT_PURPOSE_C_GENERAL, &circ);
if (retval < 1) {
/* We were either told "-1" (complete failure) or 0 (circuit in
* progress); we can't attach this stream yet. */
return retval;
}
log_debug(LD_APP|LD_CIRC,
"Attaching apconn to circ %u (stream %d sec old).",
(unsigned)circ->base_.n_circ_id, conn_age);
/* print the circ's path, so clients can figure out which circs are
* sucking. */
circuit_log_path(LOG_INFO,LD_APP|LD_CIRC,circ);
/* We have found a suitable circuit for our conn. Hurray. Do
* the attachment. */
return connection_ap_handshake_attach_chosen_circuit(conn, circ, NULL);
} else { /* we're a rendezvous conn */
origin_circuit_t *rendcirc=NULL, *introcirc=NULL;
tor_assert(!ENTRY_TO_EDGE_CONN(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 */
if (retval > 0) {
tor_assert(rendcirc);
/* one is already established, attach */
log_info(LD_REND,
"rend joined circ %u already here. attaching. "
"(stream %d sec old)",
(unsigned)rendcirc->base_.n_circ_id, conn_age);
/* Mark rendezvous circuits as 'newly dirty' every time you use
* them, since the process of rebuilding a rendezvous circ is so
* expensive. There is a tradeoff between linkability and
* feasibility, at this point.
*/
rendcirc->base_.timestamp_dirty = time(NULL);
/* We've also attempted to use them. If they fail, we need to
* probe them for path bias */
pathbias_count_use_attempt(rendcirc);
link_apconn_to_circ(conn, rendcirc, NULL);
if (connection_ap_handshake_send_begin(conn) < 0)
return 0; /* already marked, let them fade away */
return 1;
}
/* At this point we need to re-check the state, since it's possible that
* our call to circuit_get_open_circ_or_launch() changed the connection's
* state from "CIRCUIT_WAIT" to "RENDDESC_WAIT" because we decided to
* re-fetch the descriptor.
*/
if (ENTRY_TO_CONN(conn)->state != AP_CONN_STATE_CIRCUIT_WAIT) {
log_info(LD_REND, "This connection is no longer ready to attach; its "
"state changed."
"(We probably have to re-fetch its descriptor.)");
return 0;
}
if (rendcirc && (rendcirc->base_.purpose ==
CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED)) {
log_info(LD_REND,
"pending-join circ %u already here, with intro ack. "
"Stalling. (stream %d sec old)",
(unsigned)rendcirc->base_.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 */
if (retval > 0) {
/* one has already sent the intro. keep waiting. */
tor_assert(introcirc);
log_info(LD_REND, "Intro circ %u present and awaiting ack (rend %u). "
"Stalling. (stream %d sec old)",
(unsigned)introcirc->base_.n_circ_id,
rendcirc ? (unsigned)rendcirc->base_.n_circ_id : 0,
conn_age);
return 0;
}
/* now rendcirc and introcirc are each either undefined or not finished */
if (rendcirc && introcirc &&
rendcirc->base_.purpose == CIRCUIT_PURPOSE_C_REND_READY) {
log_info(LD_REND,
"ready rend circ %u already here (no intro-ack yet on "
"intro %u). (stream %d sec old)",
(unsigned)rendcirc->base_.n_circ_id,
(unsigned)introcirc->base_.n_circ_id, conn_age);
tor_assert(introcirc->base_.purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
if (introcirc->base_.state == CIRCUIT_STATE_OPEN) {
log_info(LD_REND,"found open intro circ %u (rend %u); sending "
"introduction. (stream %d sec old)",
(unsigned)introcirc->base_.n_circ_id,
(unsigned)rendcirc->base_.n_circ_id,
conn_age);
switch (rend_client_send_introduction(introcirc, rendcirc)) {
case 0: /* success */
rendcirc->base_.timestamp_dirty = time(NULL);
introcirc->base_.timestamp_dirty = time(NULL);
pathbias_count_use_attempt(introcirc);
pathbias_count_use_attempt(rendcirc);
assert_circuit_ok(TO_CIRCUIT(rendcirc));
assert_circuit_ok(TO_CIRCUIT(introcirc));
return 0;
case -1: /* transient error */
return 0;
case -2: /* permanent error */
return -1;
default: /* oops */
tor_fragile_assert();
return -1;
}
}
}
log_info(LD_REND, "Intro (%u) and rend (%u) circs are not both ready. "
"Stalling conn. (%d sec old)",
introcirc ? (unsigned)introcirc->base_.n_circ_id : 0,
rendcirc ? (unsigned)rendcirc->base_.n_circ_id : 0, conn_age);
return 0;
}
}
/** Change <b>circ</b>'s purpose to <b>new_purpose</b>. */
void
circuit_change_purpose(circuit_t *circ, uint8_t new_purpose)
{
uint8_t old_purpose;
/* Don't allow an OR circ to become an origin circ or vice versa. */
tor_assert(!!(CIRCUIT_IS_ORIGIN(circ)) ==
!!(CIRCUIT_PURPOSE_IS_ORIGIN(new_purpose)));
if (circ->purpose == new_purpose) return;
if (CIRCUIT_IS_ORIGIN(circ)) {
char old_purpose_desc[80] = "";
strncpy(old_purpose_desc, circuit_purpose_to_string(circ->purpose), 80-1);
old_purpose_desc[80-1] = '\0';
log_debug(LD_CIRC,
"changing purpose of origin circ %d "
"from \"%s\" (%d) to \"%s\" (%d)",
TO_ORIGIN_CIRCUIT(circ)->global_identifier,
old_purpose_desc,
circ->purpose,
circuit_purpose_to_string(new_purpose),
new_purpose);
}
old_purpose = circ->purpose;
circ->purpose = new_purpose;
if (CIRCUIT_IS_ORIGIN(circ)) {
control_event_circuit_purpose_changed(TO_ORIGIN_CIRCUIT(circ),
old_purpose);
}
}
/** Mark <b>circ</b> so that no more connections can be attached to it. */
void
mark_circuit_unusable_for_new_conns(origin_circuit_t *circ)
{
const or_options_t *options = get_options();
tor_assert(circ);
/* XXXX This is a kludge; we're only keeping it around in case there's
* something that doesn't check unusable_for_new_conns, and to avoid
* deeper refactoring of our expiration logic. */
if (! circ->base_.timestamp_dirty)
circ->base_.timestamp_dirty = approx_time();
if (options->MaxCircuitDirtiness >= circ->base_.timestamp_dirty)
circ->base_.timestamp_dirty = 1; /* prevent underflow */
else
circ->base_.timestamp_dirty -= options->MaxCircuitDirtiness;
circ->unusable_for_new_conns = 1;
}
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