Struct BwCircuitStat 

pub struct BwCircuitStat {

    pub circ_id: String,
    pub is_hs: bool,
    pub is_service: bool,
    pub is_hsdir: bool,
    pub is_serv_intro: bool,
    pub dropped_cells_allowed: u64,
    pub purpose: Option<String>,
    pub hs_state: Option<String>,
    pub old_purpose: Option<String>,
    pub old_hs_state: Option<String>,
    pub in_use: bool,
    pub built: bool,
    pub created_at: f64,
    pub read_bytes: u64,
    pub sent_bytes: u64,
    pub delivered_read_bytes: u64,
    pub delivered_sent_bytes: u64,
    pub overhead_read_bytes: u64,
    pub overhead_sent_bytes: u64,
    pub guard_fp: Option<String>,
    pub possibly_destroyed_at: Option<f64>,
}

Per-circuit bandwidth statistics for attack detection.

Tracks all bandwidth-related information for a single circuit, including read/written bytes, delivered/overhead bytes, and circuit state information.

Circuit Tracking

┌─────────────────────────────────────────────────────────────────────────┐
│                        BwCircuitStat Fields                              │
│                                                                          │
│  Identity          │ State              │ Bandwidth                     │
│  ──────────────────┼────────────────────┼───────────────────────────────│
│  circ_id           │ purpose            │ read_bytes                    │
│  guard_fp          │ hs_state           │ sent_bytes                    │
│  created_at        │ old_purpose        │ delivered_read_bytes          │
│                    │ old_hs_state       │ delivered_sent_bytes          │
│                    │ built              │ overhead_read_bytes           │
│                    │ in_use             │ overhead_sent_bytes           │
│                                                                          │
│  Flags             │ Attack Detection                                   │
│  ──────────────────┼────────────────────────────────────────────────────│
│  is_hs             │ dropped_cells_allowed                              │
│  is_service        │ possibly_destroyed_at                              │
│  is_hsdir          │                                                    │
│  is_serv_intro     │                                                    │
└─────────────────────────────────────────────────────────────────────────┘

Dropped Cell Detection

Dropped cells are detected using the formula:

dropped = read_bytes / CELL_PAYLOAD_SIZE - (delivered_read + overhead_read) / RELAY_PAYLOAD_SIZE

Circuit Types

Flag	Description
is_hs	Hidden service circuit (client or service)
is_service	Service-side circuit (vs client-side)
is_hsdir	HSDIR circuit for descriptor operations
is_serv_intro	Service introduction circuit

Example

use vanguards_rs::bandguards::BwCircuitStat;

let mut circ = BwCircuitStat::new("123".to_string(), true);
circ.read_bytes = 5090;  // 10 cells
circ.delivered_read_bytes = 3984;  // 8 cells delivered

let dropped = circ.dropped_read_cells();
println!("Dropped cells: {}", dropped);

See Also

• BandwidthStats - Main tracking structure
• CircuitLimitResult - Limit check results

Fields

circ_id: String

Circuit ID.

is_hs: bool

Whether this is a hidden service circuit.

is_service: bool

Whether this is a service-side circuit (vs client).

is_hsdir: bool

Whether this is an HSDIR circuit.

is_serv_intro: bool

Whether this is a service intro circuit.

dropped_cells_allowed: u64

Number of dropped cells allowed (for Tor bug workarounds).

purpose: Option<String>

Current circuit purpose.

hs_state: Option<String>

Current hidden service state.

old_purpose: Option<String>

Previous circuit purpose (before PURPOSE_CHANGED).

old_hs_state: Option<String>

Previous hidden service state.

in_use: bool

Whether the circuit is in use.

built: bool

Whether the circuit has been built.

created_at: f64

Unix timestamp when the circuit was created.

read_bytes: u64

Total bytes read on this circuit.

sent_bytes: u64

Total bytes sent on this circuit.

delivered_read_bytes: u64

Delivered read bytes (application data).

delivered_sent_bytes: u64

Delivered sent bytes (application data).

overhead_read_bytes: u64

Overhead read bytes (protocol overhead).

overhead_sent_bytes: u64

Overhead sent bytes (protocol overhead).

guard_fp: Option<String>

Guard fingerprint for this circuit.

possibly_destroyed_at: Option<f64>

Timestamp when the circuit may have been destroyed due to guard closure.

Implementations

impl BwCircuitStat

pub fn new(circ_id: String, is_hs: bool) -> Self

Creates a new circuit stat entry.

Arguments

• circ_id - The circuit ID
• is_hs - Whether this is a hidden service circuit

pub fn total_bytes(&self) -> u64

Returns the total bytes (read + sent) on this circuit.

pub fn dropped_read_cells(&self) -> i64

Calculates the number of dropped read cells.

Dropped cells are cells that were received but not delivered to the application. This can indicate an attack or a Tor bug.

Formula

dropped = read_bytes / CELL_PAYLOAD_SIZE - (delivered_read + overhead_read) / RELAY_PAYLOAD_SIZE

Returns

The number of dropped cells. Can be negative due to timing issues.

pub fn age_secs(&self) -> f64

Returns the circuit age in seconds.

pub fn age_hours(&self) -> f64

Returns the circuit age in hours.

Trait Implementations

impl Clone for BwCircuitStat

fn clone(&self) -> BwCircuitStat

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BwCircuitStat

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

Formats the value using the given formatter.