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Address Nick's comments from code review.

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Also promote log messages to notice and rate-limit them.
This commit is contained in:
Mike Perry 2012-08-16 16:29:19 -07:00
parent ec6a7effb8
commit 4e42a8a2f2
3 changed files with 217 additions and 86 deletions
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6
changes/bug6475 Normal file
View File

@ -0,0 +1,6 @@
o Minor bugfixes:
- Add internal circuit construction state to protect against
the noisy warn message "Unexpectedly high circuit_successes".
Also add some additional rate-limited notice messages to help
determine the root cause of the warn. Fixes bug 6475.
Bugfix against 0.2.3.17-beta.

282
src/or/circuitbuild.c
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@ -135,6 +135,9 @@ static entry_guard_t *entry_guard_get_by_id_digest(const char *digest);
static void bridge_free(bridge_info_t *bridge);
static int entry_guard_inc_first_hop_count(entry_guard_t *guard);
static void pathbias_count_success(origin_circuit_t *circ);
/**
* This function decides if CBT learning should be disabled. It returns
* true if one or more of the following four conditions are met:
@ -2285,44 +2288,11 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
}
log_info(LD_CIRC,"circuit built!");
circuit_reset_failure_count(0);
/* Don't count cannibalized or onehop circs for path bias */
if (circ->build_state->onehop_tunnel || circ->has_opened) {
control_event_bootstrap(BOOTSTRAP_STATUS_REQUESTING_STATUS, 0);
} else {
entry_guard_t *guard =
entry_guard_get_by_id_digest(circ->_base.n_conn->identity_digest);
if (guard) {
if (circ->path_state == PATH_STATE_DID_FIRST_HOP) {
circ->path_state = PATH_STATE_SUCCEEDED;
guard->circuit_successes++;
log_info(LD_PROTOCOL, "Got success count %u/%u for guard %s=%s",
guard->circuit_successes, guard->first_hops,
guard->nickname, hex_str(guard->identity, DIGEST_LEN));
} else {
log_info(LD_BUG,
"Succeeded circuit has strange path state %d. "
"Circuit is a %s currently %s.",
circ->path_state,
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
if (guard->first_hops < guard->circuit_successes) {
log_warn(LD_BUG, "Unexpectedly high circuit_successes (%u/%u) "
"for guard %s=%s",
guard->circuit_successes, guard->first_hops,
guard->nickname, hex_str(guard->identity, DIGEST_LEN));
}
} else {
log_info(LD_BUG,
"Completed circuit has no known guard. "
"Circuit is a %s currently %s.",
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
}
if (!can_complete_circuit && !circ->build_state->onehop_tunnel) {
const or_options_t *options = get_options();
can_complete_circuit=1;
@ -2338,6 +2308,8 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
consider_testing_reachability(1, 1);
}
}
pathbias_count_success(circ);
circuit_rep_hist_note_result(circ);
circuit_has_opened(circ); /* do other actions as necessary */
@ -2637,6 +2609,194 @@ pathbias_get_scale_factor(const or_options_t *options)
DFLT_PATH_BIAS_SCALE_THRESHOLD, 1, INT32_MAX);
}
const char *
pathbias_state_to_string(path_state_t state)
{
switch(state) {
case PATH_STATE_NEW_CIRC:
return "new";
case PATH_STATE_DID_FIRST_HOP:
return "first hop";
case PATH_STATE_SUCCEEDED:
return "succeeded";
}
return "unknown";
}
/**
* Check our circuit state to see if this is a successful first hop.
* If so, record it in the current guard's path bias first_hop count.
*
* Also check for several potential error cases for bug #6475.
*/
static int
pathbias_count_first_hop(origin_circuit_t *circ)
{
#define FIRST_HOP_NOTICE_INTERVAL (600)
static ratelim_t first_hop_notice_limit = RATELIM_INIT(FIRST_HOP_NOTICE_INTERVAL);
char *rate_msg = NULL;
/* Completely ignore one hop circuits */
if (circ->build_state->onehop_tunnel) {
tor_assert(circ->build_state->desired_path_len == 1);
return 0;
}
if (circ->cpath->state == CPATH_STATE_AWAITING_KEYS) {
/* Help track down the real cause of bug #6475: */
if (circ->has_opened && circ->path_state != PATH_STATE_DID_FIRST_HOP) {
if ((rate_msg = rate_limit_log(&first_hop_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Opened circuit is in strange path state %s. "
"Circuit is a %s currently %s. %s",
pathbias_state_to_string(circ->path_state),
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
/* Don't count cannibalized circs for path bias */
if (!circ->has_opened) {
entry_guard_t *guard;
guard = entry_guard_get_by_id_digest(
circ->_base.n_conn->identity_digest);
if (guard) {
if (circ->path_state == PATH_STATE_NEW_CIRC) {
circ->path_state = PATH_STATE_DID_FIRST_HOP;
if (entry_guard_inc_first_hop_count(guard) < 0) {
/* Bogus guard; we already warned. */
return -END_CIRC_REASON_TORPROTOCOL;
}
} else {
if ((rate_msg = rate_limit_log(&first_hop_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Unopened circuit has strange path state %s. "
"Circuit is a %s currently %s. %s",
pathbias_state_to_string(circ->path_state),
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
} else {
if ((rate_msg = rate_limit_log(&first_hop_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Unopened circuit has no known guard. "
"Circuit is a %s currently %s. %s",
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
}
} else {
/* Help track down the real cause of bug #6475: */
if (circ->path_state == PATH_STATE_NEW_CIRC) {
if ((rate_msg = rate_limit_log(&first_hop_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"A %s circuit is in cpath state %d (opened: %d). "
"Circuit is a %s currently %s. %s",
pathbias_state_to_string(circ->path_state),
circ->cpath->state, circ->has_opened,
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
}
return 0;
}
/**
* Check our circuit state to see if this is a successful circuit
* completion. If so, record it in the current guard's path bias
* success count.
*
* Also check for several potential error cases for bug #6475.
*/
static void
pathbias_count_success(origin_circuit_t *circ)
{
#define SUCCESS_NOTICE_INTERVAL (600)
static ratelim_t success_notice_limit = RATELIM_INIT(SUCCESS_NOTICE_INTERVAL);
char *rate_msg = NULL;
/* Ignore one hop circuits */
if (circ->build_state->onehop_tunnel) {
tor_assert(circ->build_state->desired_path_len == 1);
return;
}
/* Don't count cannibalized/reused circs for path bias */
if (!circ->has_opened) {
entry_guard_t *guard =
entry_guard_get_by_id_digest(circ->_base.n_conn->identity_digest);
if (guard) {
if (circ->path_state == PATH_STATE_DID_FIRST_HOP) {
circ->path_state = PATH_STATE_SUCCEEDED;
guard->circuit_successes++;
log_info(LD_PROTOCOL, "Got success count %u/%u for guard %s=%s",
guard->circuit_successes, guard->first_hops,
guard->nickname, hex_str(guard->identity, DIGEST_LEN));
} else {
if ((rate_msg = rate_limit_log(&success_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Succeeded circuit is in strange path state %s. "
"Circuit is a %s currently %s. %s",
pathbias_state_to_string(circ->path_state),
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
if (guard->first_hops < guard->circuit_successes) {
log_warn(LD_BUG, "Unexpectedly high circuit_successes (%u/%u) "
"for guard %s=%s",
guard->circuit_successes, guard->first_hops,
guard->nickname, hex_str(guard->identity, DIGEST_LEN));
}
} else {
if ((rate_msg = rate_limit_log(&success_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Completed circuit has no known guard. "
"Circuit is a %s currently %s. %s",
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
} else {
if (circ->path_state != PATH_STATE_SUCCEEDED) {
if ((rate_msg = rate_limit_log(&success_notice_limit,
approx_time()))) {
log_notice(LD_BUG,
"Opened circuit is in strange path state %s. "
"Circuit is a %s currently %s. %s",
pathbias_state_to_string(circ->path_state),
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state),
rate_msg);
}
}
}
}
/** Increment the number of times we successfully extended a circuit to
* 'guard', first checking if the failure rate is high enough that we should
* eliminate the guard. Return -1 if the guard looks no good; return 0 if the
@ -2704,60 +2864,14 @@ circuit_finish_handshake(origin_circuit_t *circ, uint8_t reply_type,
{
char keys[CPATH_KEY_MATERIAL_LEN];
crypt_path_t *hop;
int rv;
if((rv = pathbias_count_first_hop(circ)) < 0)
return rv;
if (circ->cpath->state == CPATH_STATE_AWAITING_KEYS) {
hop = circ->cpath;
/* Help track down the real cause of bug #6475: */
if (circ->has_opened && circ->path_state == PATH_STATE_NEW_CIRC) {
log_info(LD_BUG,
"Opened circuit seems new. "
"Circuit is a %s currently %s.",
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
/* Don't count cannibalized or onehop circs for path bias */
if (!circ->has_opened && !circ->build_state->onehop_tunnel) {
entry_guard_t *guard;
guard = entry_guard_get_by_id_digest(
circ->_base.n_conn->identity_digest);
if (guard) {
if (circ->path_state == PATH_STATE_NEW_CIRC) {
circ->path_state = PATH_STATE_DID_FIRST_HOP;
if (entry_guard_inc_first_hop_count(guard) < 0) {
/* Bogus guard; we already warned. */
return -END_CIRC_REASON_TORPROTOCOL;
}
} else {
log_info(LD_BUG,
"Unopened circuit has strange path state %d. "
"Circuit is a %s currently %s.",
circ->path_state,
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
} else {
log_info(LD_BUG,
"Opened circuit has no known guard. "
"Circuit is a %s currently %s.",
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
}
} else {
/* Help track down the real cause of bug #6475: */
if (circ->path_state == PATH_STATE_NEW_CIRC) {
log_info(LD_BUG,
"New circuit is in cpath state %d (opened: %d). "
"Circuit is a %s currently %s.",
circ->cpath->state, circ->has_opened,
circuit_purpose_to_string(circ->_base.purpose),
circuit_state_to_string(circ->_base.state));
}
hop = onion_next_hop_in_cpath(circ->cpath);
if (!hop) { /* got an extended when we're all done? */
log_warn(LD_PROTOCOL,"got extended when circ already built? Closing.");

13
src/or/or.h
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@ -2596,9 +2596,20 @@ typedef struct circuit_t {
* circuit. */
#define MAX_RELAY_EARLY_CELLS_PER_CIRCUIT 8
/**
* Describes the circuit building process in simplified terms based
* on the path bias accounting state for a circuit. Created to prevent
* overcounting due to unknown cases of circuit reuse. See Bug #6475.
*/
typedef enum {
/** This circuit is "new". It has not yet completed a first hop
* or been counted by the path bias code. */
PATH_STATE_NEW_CIRC = 0,
/** This circuit has completed a first hop, and has been counted by
* the path bias logic. */
PATH_STATE_DID_FIRST_HOP = 1,
/** This circuit has been completely built, and has been counted as
* successful by the path bias logic. */
PATH_STATE_SUCCEEDED = 2,
} path_state_t;
@ -2637,7 +2648,7 @@ typedef struct origin_circuit_t {
/** Kludge to help us prevent the warn in bug #6475 and eventually
* debug why we are not seeing first hops in some cases. */
path_state_t path_state;
path_state_t path_state : 2;
/** Set iff this is a hidden-service circuit which has timed out
* according to our current circuit-build timeout, but which has