Struct TimeoutStats 

pub struct TimeoutStats {
    pub circuits: HashMap<String, CircuitStat>,
    pub all_launched: u64,
    pub all_built: u64,
    pub all_timeout: u64,
    pub hs_launched: u64,
    pub hs_built: u64,
    pub hs_timeout: u64,
    pub record_timeouts: bool,
}

Circuit build timeout statistics.

Tracks circuit build statistics for all circuits and hidden service circuits separately, allowing comparison of timeout rates.

Statistics Tracked

Statistic	Description
all_launched	Total circuits that started building
all_built	Circuits that completed successfully
all_timeout	Circuits that timed out
hs_launched	Hidden service circuits started
hs_built	HS circuits completed
hs_timeout	HS circuits that timed out

Example

use vanguards_rs::cbtverify::TimeoutStats;

let mut stats = TimeoutStats::new();

// Track a circuit launch
stats.add_circuit("123", true);
assert_eq!(stats.all_launched, 1);
assert_eq!(stats.hs_launched, 1);

// Track circuit completion
stats.built_circuit("123");
assert_eq!(stats.all_built, 1);
assert_eq!(stats.hs_built, 1);

// Check timeout rates
assert_eq!(stats.timeout_rate_all(), 0.0);
assert_eq!(stats.timeout_rate_hs(), 0.0);

CBT Event Handling

The statistics respond to Tor’s CBT algorithm events:

• COMPUTED: CBT algorithm has computed a new timeout value
• RESET: CBT algorithm has been reset (e.g., after network change)

After a RESET, statistics are zeroed and recording is paused until the next COMPUTED event.

See Also

• CircuitStat - Individual circuit tracking
• crate::control - Event dispatch to CBT verification

Fields

circuits: HashMap<String, CircuitStat>

Circuits currently being tracked (not yet built or timed out).

all_launched: u64

Total circuits launched.

all_built: u64

Total circuits successfully built.

all_timeout: u64

Total circuits that timed out.

hs_launched: u64

Hidden service circuits launched.

hs_built: u64

Hidden service circuits successfully built.

hs_timeout: u64

Hidden service circuits that timed out.

record_timeouts: bool

Whether to record timeouts (false after RESET, true after COMPUTED).

Implementations

impl TimeoutStats

pub fn new() -> Self

Creates a new timeout statistics tracker.

pub fn zero_fields(&mut self)

Resets all counters to zero.

pub fn circ_event( &mut self, circ_id: &str, status: &str, purpose: &str, hs_state: Option<&str>, reason: Option<&str>, )

Handles a circuit event.

Tracks circuit state transitions and updates statistics accordingly.

Arguments

• circ_id - The circuit ID
• status - The circuit status (LAUNCHED, BUILT, FAILED, CLOSED)
• purpose - The circuit purpose
• hs_state - The hidden service state (if any)
• reason - The close/fail reason (if any)

pub fn cbt_event(&mut self, set_type: &str, timeout_rate: Option<f64>)

Handles a CBT (Circuit Build Timeout) event.

Processes COMPUTED and RESET events from Tor’s circuit build timeout algorithm.

Arguments

• set_type - The CBT event type (COMPUTED, RESET)
• timeout_rate - Tor’s reported timeout rate (if available)

pub fn add_circuit(&mut self, circ_id: &str, is_hs: bool)

Adds a new circuit to tracking.

pub fn built_circuit(&mut self, circ_id: &str)

Records a circuit as successfully built.

pub fn closed_circuit(&mut self, circ_id: &str)

Records a circuit as closed before completion.

If we are closed but still in circuits, then we closed before being built or timing out. Don’t count as a launched circuit.

pub fn timeout_circuit(&mut self, circ_id: &str)

Records a circuit as timed out.

pub fn timeout_rate_all(&self) -> f64

Calculates the timeout rate for all circuits.

Returns the ratio of timed out circuits to launched circuits.

pub fn timeout_rate_hs(&self) -> f64

Calculates the timeout rate for hidden service circuits.

Returns the ratio of timed out HS circuits to launched HS circuits.

pub fn pending_count(&self) -> usize

Returns the number of circuits currently being tracked.

Trait Implementations

impl Clone for TimeoutStats

fn clone(&self) -> TimeoutStats

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TimeoutStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TimeoutStats

fn default() -> Self

Returns the “default value” for a type.