ipfrs-network 0.1.0

# ipfrs-network TODO

## ✅ Completed (Phases 1-3)

### Basic Networking Structure
- ✅ Initial libp2p setup structure
- ✅ Basic swarm configuration
- ✅ Peer ID types and management

### Phase 4 - Swarm & Transport (Partial)
- ✅ **Set up rust-libp2p swarm** with Tokio runtime
  - Swarm configuration with IpfrsBehaviour
  - Event handling loop with async select
  - Graceful shutdown support

- ✅ **Configure QUIC** as primary transport
  - QUIC transport setup via libp2p-quic
  - Connection multiplexing

- ✅ **Add TCP fallback** transport
  - TCP transport configuration with noise+yamux
  - Automatic fallback logic (QUIC || TCP)
  - Keep-alive via ping protocol (15s interval)

- ✅ **Implement PeerID generation** and management
  - Ed25519 key pair generation
  - PeerID derivation
  - Persistence to disk (identity.key)

- ✅ **Implement Kademlia DHT** setup
  - Kademlia configuration (server mode)
  - Replication factor = 20
  - Query timeout = 60s

- ✅ **Add bootstrap node** configuration
  - Custom bootstrap list support
  - Bootstrap protocol

- ✅ **Implement mDNS** for local network discovery
  - mDNS service (tokio)
  - Local peer discovery
  - Auto-connection via events

- ✅ **Create peer store** for known peers
  - In-memory peer database (DashMap)
  - Connection history tracking
  - Peer metadata (latency, reputation)
  - Automatic pruning

- ✅ **Add connection metrics** tracking
  - Connection established/failed/closed
  - Bandwidth metrics
  - DHT metrics
  - Protocol metrics

---

## Phase 4: Swarm & Transport Implementation (Remaining)

### DHT Bootstrap
- ✅ **Create DHT initialization** sequence
  - Initial peer discovery via bootstrap_dht()
  - Routing table population
  - DhtManager with query/peer caching
  - Target: Fast network join

- ✅ **Test connectivity** to public IPFS network
  - IPFS compatibility testing module (ipfs_compat.rs)
  - Connect to IPFS bootstrap nodes
  - Verify protocol interoperability (identify, ping)
  - DHT query testing
  - Provider record compatibility
  - Comprehensive test results with metrics
  - Example: ipfs_connectivity_test.rs
  - Target: IPFS compatibility ✅

### Peer Discovery
- ✅ **Add bootstrap peer dialing**
  - Dial bootstrap peers
  - Connection retry logic with exponential backoff
  - Circuit breaker pattern for failing peers
  - Target: Reliable bootstrap

- ✅ **Implement peer information persistence**
  - Save peer info to disk (JSON)
  - Load on startup
  - Prune stale entries
  - Target: Fast reconnection

### Basic Connectivity
- ✅ **Implement dial/listen** operations
  - Dial to peers via connect()
  - Listen on addresses via start()
  - Multi-address support
  - Target: Flexible connectivity

- ✅ **Add connection event** handling
  - Connection established with endpoint & duration
  - Connection closed with cause
  - Connection errors with details
  - NAT status changes
  - DHT bootstrap events
  - Listening address events
  - Target: Observable connections

- ✅ **Create keep-alive mechanism**
  - Periodic pings (15s interval)
  - Idle timeout detection (60s)
  - Connection maintenance
  - Target: Stable connections

- ✅ **Add connection metrics**
  - Connected peer count tracking
  - Bandwidth metrics framework
  - Connection duration in events
  - Target: Observable metrics

---

## Phase 5: Advanced Routing (Priority: High)

### Content Routing
- ✅ **Implement provider record** publishing
  - Announce content via provide()
  - TTL management in DhtConfig
  - Re-announcement via DhtManager
  - Target: Content discoverability

- ✅ **Add provider record queries** (GET_PROVIDERS)
  - Query for providers via find_providers()
  - Multi-provider results
  - Result caching in DhtManager
  - Target: Find content sources

- ✅ **Create provider record refresh** mechanism
  - Automatic refresh via DhtManager
  - Configurable TTL (24h default, 12h refresh)
  - Background task with tokio::spawn
  - Track provider records
  - Target: Always-discoverable content

- ✅ **Add provider record cache** with TTL
  - Cache provider records
  - TTL-based expiration
  - LRU eviction when at capacity
  - Cache statistics (hits, misses, evictions)
  - Target: Reduce DHT load

### Peer Routing
- ✅ **Implement FIND_NODE** operation
  - Query for peers via find_node()
  - Iterative lookup via Kademlia
  - Closest peers selection via get_closest_local_peers()
  - Routing table info via get_routing_table_info()
  - Target: Peer discovery

- ✅ **Add closest peer queries**
  - XOR distance metric (Kademlia)
  - K-closest peers from routing table
  - Efficient lookup
  - Target: Routing optimization

- ✅ **Create peer routing cache**
  - Cache routing results in DhtManager
  - TTL-based expiration (5min query cache, 1h peer cache)
  - LRU eviction at max capacity
  - Cache statistics (hits/misses)
  - Target: Fast routing

- ✅ **Implement peer info exchange**
  - Exchange peer metadata via Identify protocol
  - Address discovery via add_peer_address()
  - Protocol support (/ipfrs/1.0.0)
  - Target: Rich peer info

### DHT Optimizations
- ✅ **Tune Kademlia parameters** (k-bucket size, alpha)
  - KademliaConfig structure with tunable parameters
  - Alpha concurrency (default: 3)
  - Replication factor (default: 20)
  - Query timeout (default: 60s)
  - K-bucket size configuration (default: 20)
  - Target: Fast and reliable DHT ✅

- ✅ **Implement iterative query optimization**
  - Parallel queries (via Kademlia alpha parameter)
  - Early termination based on result quality
  - Query pipelining for concurrent operations
  - Query performance tracking and metrics
  - Adaptive quality scoring
  - Timeout handling
  - Target: Low-latency lookups ✅

- ✅ **Add query result caching**
  - Cache DHT query results in DhtManager
  - TTL-based invalidation (5 min default)
  - Hit rate tracking (cache_hits/cache_misses stats)
  - Max capacity limit (10,000 queries)
  - Target: Reduce redundant queries

- ✅ **Create DHT health monitoring**
  - Routing table health via DhtHealth
  - Query success rate tracking (successful_queries/failed_queries)
  - Health score calculation (0.0-1.0)
  - Health status (Healthy/Degraded/Unhealthy/Unknown)
  - Cache hit rate monitoring
  - is_healthy() check method
  - Target: Observable DHT health

### NAT Traversal
- ✅ **Implement AutoNAT protocol**
  - Detect NAT type via autonat::Behaviour
  - Determine external address via autonat::Event::StatusChanged
  - Reachability testing (inbound/outbound probes)
  - NatStatusChanged event emission
  - Target: NAT awareness ✅

- ✅ **Add hole punching** support (DCUtR)
  - DCUtR behaviour integrated (dcutr::Behaviour)
  - Direct connection upgrade capability
  - Event handling for DCUtR coordination
  - Fallback to relay (via relay_client)
  - Target: P2P through NAT ✅

- ✅ **Configure relay support** (Circuit Relay v2)
  - Relay client behaviour (relay::client::Behaviour)
  - Relay client event handling
  - Integration with swarm
  - Target: Always reachable ✅

- ✅ **Add external address discovery**
  - Learn external addresses via AutoNAT
  - Automatic tracking on Public status (external_addrs tracking)
  - Clear addresses when behind NAT
  - get_external_addresses() method
  - is_publicly_reachable() check
  - Multiple address support
  - Target: Correct addressing ✅

---

## Phase 6: Protocol Extensions (Priority: Medium)

### Custom Protocols
- ✅ **Define protocol ID** for TensorSwap
  - ProtocolId structure with name + version
  - ProtocolVersion with semantic versioning (major.minor.patch)
  - Protocol string format: /ipfrs/{name}/{version}
  - Parsing and validation
  - Target: Custom protocols ✅

- ✅ **Implement protocol negotiation**
  - ProtocolVersion compatibility checking
  - find_compatible() for version negotiation
  - Highest compatible version selection
  - Capability advertisement via ProtocolCapabilities
  - Target: Flexible protocols ✅

- ✅ **Add protocol version compatibility**
  - Semantic versioning implementation
  - Backward compatibility checks (same major, minor >=)
  - Version parsing and display
  - Migration support through version negotiation
  - Target: Evolving protocols ✅

- ✅ **Create protocol handler registry**
  - ProtocolRegistry for handler management
  - Dynamic handler registration/unregistration
  - Handler lifecycle (initialize/shutdown)
  - Protocol capability advertisement
  - 15 comprehensive tests
  - Target: Extensible protocols ✅

### Semantic DHT (v0.3.0)
- ✅ **Design vector-based DHT extension**
  - Embedding-based routing via LSH
  - Semantic closeness using distance metrics
  - Protocol specification complete
  - SemanticDht module implementation
  - Target: Semantic routing ✅

- ✅ **Implement approximate nearest neighbor** routing
  - Vector distance routing (Euclidean, Cosine, Manhattan, Dot Product)
  - LSH-based hash computation for embedding mapping
  - Result ranking by similarity score
  - Target: Distributed ANN ✅

- ✅ **Add embedding-based peer discovery**
  - LSH hash to peer mapping
  - Query result caching with TTL
  - Semantic query execution
  - Target: Semantic clustering ✅

- ✅ **Create semantic namespace** support
  - Multiple embedding spaces (text, image, audio)
  - Namespace isolation via NamespaceId
  - Per-namespace LSH configuration
  - Target: Multi-modal routing ✅

### GossipSub
- ✅ **Implement topic-based pub/sub**
  - Topic subscription/unsubscription
  - Message publishing with size limits
  - Topic mesh peer management
  - GossipSubManager implementation
  - Target: Pub/sub messaging ✅

- ✅ **Add message deduplication**
  - Message ID tracking via MessageId
  - Seen message cache with TTL
  - Automatic cache cleanup
  - Duplicate detection on handle_message
  - Target: Efficient delivery ✅

- ✅ **Create peer scoring** for mesh optimization
  - Topic-specific and overall peer scoring
  - Score calculation based on valid/invalid messages
  - Identify low-scoring peers for pruning
  - Mesh quality maintenance
  - Target: Robust mesh ✅

- ✅ **Support content announcement broadcasts**
  - Standard topics (content_announce, peer_announce, dht_events)
  - Topic-based message publishing
  - Mesh-based efficient fan-out
  - Statistics per topic
  - Target: Content discovery ✅

### Connection Pooling
- ✅ **Implement intelligent connection limits**
  - Max connections (total, inbound, outbound)
  - Direction-based limits
  - Reserved slots for important peers
  - Target: Resource management

- ✅ **Add priority-based connection pruning**
  - Score connections based on activity
  - Prune low-score connections
  - Reserve slots for important peers
  - Target: Quality connections

- ✅ **Create connection reservation** system
  - Reserve for important peers
  - Ban list for malicious peers
  - Idle connection detection
  - Target: Guaranteed connectivity

- ✅ **Add latency-based peer ranking**
  - Track latency per connection
  - Connection value calculation
  - Prefer low-latency peers in pruning
  - Target: Performance optimization

---

## Phase 7: Edge & ARM Optimization (Priority: Medium)

### ARM Performance
- ✅ **Profile on ARM devices** (RPi, Jetson)
  - ArmProfiler module (arm_profiler.rs) - 540+ lines
  - Performance profiling utilities
  - CPU, memory, throughput, latency tracking
  - Device auto-detection (Raspberry Pi, Jetson, Generic)
  - Percentile latency analysis (P95, P99)
  - Thermal monitoring support
  - Device-specific configurations
  - 12 comprehensive unit tests
  - Example: arm_profiling.rs
  - Target: ARM optimization ✅

- ✅ **Optimize for low-power operation**
  - AdaptivePolling module (completed)
  - BandwidthThrottle module (completed)
  - QueryBatcher module (completed)
  - BackgroundMode support (completed)
  - Target: Power efficiency ✅

- ✅ **Tune connection limits** for constrained devices
  - NetworkConfig with max_connections, max_inbound, max_outbound
  - Preset configurations with appropriate limits
  - Low-memory: 16 connections
  - IoT: 32 connections
  - Mobile: 64 connections
  - Server: unlimited
  - Connection buffer tuning integrated
  - Target: Embedded devices ✅

- ✅ **Add ARM-specific benchmarks**
  - Comprehensive benchmark suite (/tmp/ipfrs_network_arm_benchmarks.rs)
  - Node creation benchmarks (IoT, low-memory)
  - Component benchmarks (peer store, memory monitor, etc.)
  - Performance benchmarks (CPU under load, DHT operations)
  - Memory footprint measurements
  - Cross-platform comparison support
  - ARMv7 and AArch64 compatibility
  - Example: Runnable benchmark binary
  - Target: Performance tracking ✅

### Battery Efficiency
- ✅ **Implement adaptive polling** intervals
  - Dynamic poll interval via AdaptivePolling
  - Activity-based adjustment (High/Moderate/Low/Idle/Sleep)
  - Sleep mode detection with configurable threshold
  - Preset configs (mobile, IoT, low-power, high-performance)
  - 15 comprehensive tests
  - Target: Battery life ✅

- ✅ **Add sleep mode** for inactive connections
  - Automatic sleep mode when inactive
  - Configurable sleep threshold and interval
  - Wake on activity detection
  - Part of AdaptivePolling module
  - Target: Power saving ✅

- ✅ **Create bandwidth throttling** options
  - Token bucket rate limiting via BandwidthThrottle
  - Independent upload/download limits
  - Burst capacity support
  - Preset configs (mobile, IoT, low-power)
  - Dynamic configuration updates
  - 14 comprehensive tests
  - Example: bandwidth_throttling.rs
  - Target: Network efficiency ✅

- ✅ **Optimize DHT query frequency**
  - Query batching via QueryBatcher
  - Rate limiting with adaptive adjustment
  - Query deduplication (5s window)
  - Preset configs (mobile, IoT, low-power, high-performance)
  - Batching efficiency tracking
  - 15 comprehensive tests
  - Target: Reduced network traffic ✅

### Mobile Support
- ✅ **Handle network switches** (WiFi ↔ Cellular)
  - NetworkMonitor module for interface detection
  - NetworkInterface with type detection (WiFi, Cellular, Ethernet)
  - NetworkChange events (InterfaceAdded, InterfaceRemoved, PrimaryInterfaceChanged)
  - Priority-based interface selection
  - Debouncing for stable detection
  - Preset configs: mobile(), server()
  - 12 comprehensive unit tests
  - Example: network_monitoring.rs
  - Target: Mobile resilience ✅

- ✅ **Implement connection migration** for QUIC
  - ConnectionMigrationManager module (connection_migration.rs)
  - Automatic detection of network changes
  - Seamless connection migration without data loss
  - State preservation during migration
  - Retry logic for failed migrations
  - MigrationConfig presets: mobile(), conservative()
  - Migration states: Idle, Initiated, Validating, Migrating, Completed, Failed
  - Statistics tracking (attempts, successes, failures, duration)
  - Migration cooldown and timeout handling
  - 17 comprehensive unit tests
  - Example: connection_migration.rs
  - Target: No interruption ✅

- ✅ **Add pause/resume** for background mode
  - BackgroundModeManager implementation
  - BackgroundState lifecycle (Active, Paused, Pausing, Resuming)
  - Configurable pause behavior (DHT, announcements, connections)
  - Time tracking for foreground/background durations
  - Statistics tracking
  - Preset configs: mobile(), balanced(), server()
  - 17 comprehensive unit tests
  - Example: background_mode.rs
  - Target: Mobile integration ✅

- ✅ **Create offline queue** for requests
  - Request queuing via OfflineQueue
  - Priority-based ordering (Low/Normal/High/Critical)
  - Automatic replay when online
  - Request timeout and expiration
  - Retry logic with configurable attempts
  - Batch replay support
  - Preset configs (mobile, IoT)
  - 13 comprehensive tests
  - Target: Offline resilience ✅

### Memory Optimization
- ✅ **Reduce peer store memory footprint**
  - PeerStoreConfig with configurable limits
  - Max peers (100 low-memory to 5000 server)
  - Max addresses per peer (2-20)
  - Max latency samples (3-20)
  - Max protocols per peer (5-50)
  - Preset configs: low_memory(), iot(), mobile(), server()
  - Target: Low memory usage ✅

- ✅ **Implement connection buffer tuning**
  - Configurable connection_buffer_size in NetworkConfig
  - Range: 8 KB (low-memory) to 128 KB (high-performance)
  - Integrated with preset configurations
  - Target: Memory efficiency ✅

- ✅ **Add memory usage monitoring**
  - Component-level tracking via MemoryMonitor
  - Budget enforcement (per-component and total)
  - Automatic cleanup triggering
  - Memory leak detection (growth rate analysis)
  - Preset configs (low-memory, IoT, mobile)
  - Human-readable formatting
  - 14 comprehensive tests
  - Target: Observable memory ✅

- ✅ **Create low-memory mode**
  - NetworkConfig::low_memory() preset
  - 16 connections max, 8 KB buffers
  - Reduced DHT parameters
  - Disabled mDNS and NAT traversal for memory saving
  - PeerStoreConfig::low_memory() integration
  - Example: low_memory_node.rs
  - Target: Constrained devices ✅

---

## Phase 8: Reliability & Testing (Priority: Continuous)

### Error Handling
- ✅ **Handle connection failures** gracefully
  - Retry logic with exponential backoff
  - Configurable max retries
  - Circuit breaker pattern
  - Target: Resilient connections

- ✅ **Implement retry logic** with backoff
  - Configurable retries
  - Exponential backoff with max
  - Per-peer backoff tracking
  - Target: Automatic recovery

- ✅ **Add circuit breaker** for failing peers
  - Detect consecutive failures
  - Open circuit after threshold
  - Timeout-based reset
  - Target: Prevent cascading failures

- ✅ **Create fallback strategies**
  - FallbackManager with comprehensive strategy handling
  - Alternative peer selection
  - Relay fallback for NAT traversal
  - Degraded mode operation
  - Retry with exponential backoff
  - Circuit breaker pattern
  - FallbackResult wrapper for operation results
  - 13 comprehensive tests
  - Target: Always available ✅

### Testing
- ✅ **Unit tests** for all network components
  - 90+ comprehensive unit tests
  - Bitswap protocol tests (10 tests)
  - Connection manager tests (8 tests)
  - DHT tests (10 tests)
  - Health checker tests (6 tests)
  - Logging tests (9 tests)
  - Metrics tests (4 tests)
  - Peer store tests (7 tests)
  - Provider cache tests (7 tests)
  - Bootstrap tests (5 tests)
  - IPFS compatibility tests (6 tests)
  - Connection migration tests (17 tests)
  - Target: Strong test coverage ✅

- ✅ **Integration tests** with IPFS Kubo nodes
  - Comprehensive test suite (/tmp/ipfrs_network_integration_tests.rs)
  - Bootstrap node connectivity testing
  - DHT query compatibility verification
  - Provider record interoperability
  - Full IPFS compatibility test suite
  - Local IPFS node connection testing
  - Peer exchange verification
  - Network resilience testing
  - DHT lookup performance benchmarks
  - Protocol version compatibility
  - Content routing tests
  - Target: IPFS ecosystem compatibility ✅

- ✅ **Chaos testing** (network partitions, packet loss)
  - Comprehensive chaos test suite (/tmp/ipfrs_network_chaos_tests.rs)
  - Network partition recovery simulation
  - Connection churn testing (rapid connect/disconnect)
  - Connection limits stress testing
  - DHT query storm testing
  - Bandwidth tracking stress testing
  - Memory usage stress testing
  - Concurrent operations testing
  - Repeated failure recovery testing
  - Massive peer list testing (1000+ addresses)
  - Startup/shutdown stress testing
  - Target: Robust networking ✅

- ✅ **Stress tests** (1000+ concurrent connections)
  - High connection count testing (1000+ peers)
  - Sustained load testing
  - Resource exhaustion testing
  - Memory stress testing
  - Concurrent operations stress testing
  - All tests in chaos test suite
  - Target: Scalability validation ✅

### Monitoring
- ✅ **Add Prometheus metrics** export
  - Prometheus registry creation
  - Connection metrics (established, failed, active)
  - DHT metrics (queries, providers)
  - Bandwidth metrics (sent, received)
  - Uptime tracking
  - export_prometheus() method
  - Target: Observability ✅

- ✅ **Create health check** endpoints
  - Overall health status (Healthy/Degraded/Unhealthy/Unknown)
  - Component health (connections, DHT, bandwidth)
  - Health history tracking (last 100 checks)
  - Health score calculation (0.0-1.0)
  - HealthChecker with comprehensive reporting
  - Target: Monitoring integration ✅

- ✅ **Implement event logging**
  - Structured logging module
  - NetworkEventType enumeration
  - Log levels (Trace, Debug, Info, Warn, Error)
  - LoggingConfig for customization
  - Contextual information support
  - Target: Debugging ✅

- ✅ **Add tracing** for debugging
  - Structured tracing spans (network, DHT, connection)
  - OperationContext for context propagation
  - Span tracking with field recording
  - Performance profiling support
  - Target: Deep debugging ✅

### Documentation
- ✅ **Write network architecture** guide
  - Component diagram with full system overview
  - Data flow for content announcement/discovery
  - Design decisions and trade-offs explained
  - docs/ARCHITECTURE.md (550+ lines)
  - Target: Architecture docs ✅

- ✅ **Add peer discovery** documentation
  - All discovery mechanisms (Bootstrap, DHT, mDNS, Peer Exchange)
  - Configuration options for every scenario
  - Comprehensive troubleshooting section
  - docs/PEER_DISCOVERY.md (650+ lines)
  - Target: Discovery guide ✅

- ✅ **Create NAT traversal troubleshooting** guide
  - All NAT types explained (Full Cone, Restricted, Symmetric, Double)
  - Complete diagnostic procedures
  - Solutions for common problems
  - Configuration examples by use case
  - docs/NAT_TRAVERSAL.md (700+ lines)
  - Target: NAT help ✅

- ✅ **Document all configuration options**
  - All 10 configuration structures documented
  - Default values and ranges specified
  - Best practices and trade-offs
  - Complete examples for every scenario
  - docs/CONFIGURATION.md (850+ lines)
  - Target: Configuration guide ✅

---

## Future Enhancements

### Advanced Transport
- ✅ **Support QUIC multipath**
  - Multiple network paths management via MultipathQuicManager
  - Path quality monitoring (RTT, bandwidth, packet loss, jitter)
  - Multiple path selection strategies (Round Robin, Quality Based, Lowest Latency, Highest Bandwidth, Redundant)
  - Automatic path migration based on quality thresholds
  - Load balancing and traffic distribution
  - Configuration presets (low-latency, high-bandwidth, high-reliability, mobile)
  - 15 comprehensive unit tests
  - Example: multipath_quic.rs with 5 scenarios
  - Target: Resilient transport ✅

- ✅ **Implement connection quality prediction**
  - Historical data tracking per peer
  - Quality scoring based on latency, bandwidth, reliability, uptime
  - Exponential moving average for smooth predictions
  - Configurable weights for different metrics
  - Proactive connection switching recommendations
  - Peer ranking and best peer selection
  - Configuration presets (low-latency, high-bandwidth, high-reliability)
  - 14 comprehensive unit tests
  - Example: quality_prediction.rs
  - Target: Smart routing ✅

### Geographic Optimization
- ✅ **Add geographic routing optimization**
  - GeoLocation with latitude/longitude coordinates
  - Great-circle distance calculation using Haversine formula
  - Proximity-based peer ranking
  - Regional clustering (North America, South America, Europe, Asia, Africa, Oceania)
  - Latency estimation based on distance
  - Same-region bonus for preferring nearby regions
  - Configurable thresholds and limits
  - Configuration presets (low_latency, global, regional)
  - GeoIP lookup infrastructure (placeholder for future database integration)
  - 16 comprehensive unit tests
  - Example: geographic_routing.rs
  - Target: Latency optimization ✅

### Extensibility
- ✅ **Support custom DHT implementations**
  - DhtProvider trait for pluggable DHT backends
  - DhtProviderRegistry for dynamic provider management
  - DhtCapabilities for feature advertisement
  - KademliaDhtProvider reference implementation
  - Support for content routing, peer routing, and KV storage
  - Provider statistics and health monitoring
  - Easy integration of custom DHT algorithms
  - 14 comprehensive unit tests
  - Example: custom_dht.rs
  - Target: Flexible routing ✅

### Privacy
- ✅ **Integration with Tor** for privacy
  - TorManager for Tor network integration
  - SOCKS5 proxy support for connecting through Tor
  - Onion routing with circuit management
  - Hidden services (.onion) hosting and creation
  - Stream isolation for maximum privacy
  - Circuit state management (Building, Ready, Active, Degraded, Failed, Closing)
  - Configuration presets (high-privacy, high-performance, censorship-resistant)
  - Onion address validation (v2 and v3)
  - Statistics and monitoring (circuits, streams, bandwidth)
  - 12 comprehensive unit tests
  - Example: tor_privacy.rs with 5 complete scenarios
  - Target: Privacy-preserving networking ✅

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