Module cbtverify 

Circuit Build Timeout verification for monitoring circuit construction timing.

This module monitors circuit build timeouts to detect anomalies in circuit construction timing that could indicate attacks or network issues.

Overview

The CBT verifier tracks:

• Launched circuits: Circuits that have started building
• Built circuits: Circuits that completed successfully
• Timed out circuits: Circuits that exceeded the build timeout
• Hidden service circuits: Separate tracking for HS circuits

Timeout Rate Monitoring

The module calculates timeout rates to detect anomalies:

• Overall timeout rate: all_timeout / all_launched
• HS timeout rate: hs_timeout / hs_launched

Elevated HS timeout rates compared to overall rates may indicate targeted attacks against hidden services.

What This Module Does NOT Do

• Circuit building: This module only monitors, not builds circuits
• Timeout adjustment: Tor manages its own CBT algorithm
• Attack mitigation: This module detects but doesn’t prevent attacks

See Also

• crate::control - Event handling that calls CBT verification
• crate::bandguards - Related bandwidth monitoring
• Python vanguards cbtverify

Structs

CircuitStat

Per-circuit tracking for timeout statistics.

TimeoutStats

Circuit build timeout statistics.