durch
0a6f78a921
Initial implementation of the Lewes Protocol (LP) for gateway registration: - Add nym-lp crate with Noise protocol handshake - Add LP listener to gateway for handling registrations - Add LP client for registration flow - Integrate KKT for post-quantum KEM key exchange - Integrate PSQ for post-quantum PSK derivation - Add Ed25519 authentication throughout - Add docker/localnet support for testing Co-authored-by: Jędrzej Stuczyński <jedrzej.stuczynski@gmail.com>
261 lines
16 KiB
Markdown
261 lines
16 KiB
Markdown
# LP Registration Protocol - Technical Walkthrough
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**Branch**: `drazen/lp-reg`
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**Status**: Implementation complete, testing in progress
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**Audience**: Engineering team, technical demo
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---
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## Executive Summary
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LP Registration is a **fast, direct registration protocol** that allows clients to connect to Nym gateways without traversing the mixnet. It's designed primarily for dVPN use cases where users need quick WireGuard peer setup with sub-second latency.
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### Key Characteristics
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| Aspect | LP Registration | Traditional Mixnet Registration |
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|--------|----------------|--------------------------------|
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| **Latency** | Sub-second (100ms-1s) | Multi-second (3-10s) |
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| **Transport** | Direct TCP (port 41264) | Through mixnet layers |
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| **Reliability** | Guaranteed delivery | Probabilistic delivery |
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| **Anonymity** | Client IP visible to gateway | Network-level anonymity |
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| **Use Case** | dVPN, low-latency services | Privacy-critical applications |
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| **Security** | Noise XKpsk3 + ChaCha20-Poly1305 | Sphinx packet encryption |
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### Protocol Stack
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```
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┌─────────────────────────────────────────────────────────────┐
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│ Application Layer │
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│ WireGuard Peer Registration (dVPN) / Mixnet Client. │
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└─────────────────────────────────────────────────────────────┘
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↓
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┌─────────────────────────────────────────────────────────────┐
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│ LP Registration Layer │
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│ LpRegistrationRequest / LpRegistrationResponse │
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└─────────────────────────────────────────────────────────────┘
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↓
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┌─────────────────────────────────────────────────────────────┐
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│ Noise XKpsk3 Protocol Layer │
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│ ChaCha20-Poly1305 Encryption + Authentication │
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│ Replay Protection (1024-pkt window) │
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└─────────────────────────────────────────────────────────────┘
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↓
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┌─────────────────────────────────────────────────────────────┐
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│ Transport Layer │
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│ TCP (length-prefixed packet framing) │
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└─────────────────────────────────────────────────────────────┘
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```
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---
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## Architecture Overview
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### High-Level Component Diagram
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```
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┌──────────────────────────────────────────────────────────────────────┐
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│ CLIENT SIDE │
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├──────────────────────────────────────────────────────────────────────┤
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│ │
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│ ┌─────────────────────────────────────────────────────────────┐ │
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│ │ nym-registration-client (Client Library) │ │
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│ │ nym-registration-client/src/lp_client/client.rs:39-62 │ │
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│ │ │ │
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│ │ • LpRegistrationClient │ │
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│ │ • TCP connection management │ │
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│ │ • Packet serialization/framing │ │
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│ │ • Integration with BandwidthController │ │
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│ └────────────────────┬────────────────────────────────────────┘ │
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│ │ │
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│ ┌────────────────────┴─────────────────────────────────────────┐ │
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│ │ common/nym-lp (Protocol Library) │ │
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│ │ common/nym-lp/src/ (multiple modules) │ │
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│ │ │ │
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│ │ • LpStateMachine (state_machine.rs:96-420) │ │
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│ │ • Noise XKpsk3 (noise_protocol.rs:40-88) │ │
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│ │ • PSK derivation (psk.rs:28-52) │ │
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│ │ • ReplayValidator (replay/validator.rs:25-125) │ │
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│ │ • Message types (message.rs, packet.rs) │ │
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│ └──────────────────────────────────────────────────────────────┘ │
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│ │
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└──────────────────────────────────────────────────────────────────────┘
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│
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│ TCP (port 41264)
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│ Length-prefixed packets
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│
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▼
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┌──────────────────────────────────────────────────────────────────────┐
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│ GATEWAY SIDE │
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├──────────────────────────────────────────────────────────────────────┤
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│ │
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│ ┌─────────────────────────────────────────────────────────────┐ │
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│ │ LpListener (TCP Accept Loop) │ │
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│ │ gateway/src/node/lp_listener/mod.rs:226-270 │ │
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│ │ │ │
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│ │ • Binds to 0.0.0.0:41264 │ │
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│ │ • Spawns LpConnectionHandler per connection │ │
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│ │ • Metrics: active_lp_connections │ │
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│ └────────────────────┬────────────────────────────────────────┘ │
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│ │ │
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│ ┌────────────────────▼─────────────────────────────────────────┐ │
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│ │ LpConnectionHandler (Per-Connection) │ │
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│ │ gateway/src/node/lp_listener/handler.rs:101-216 │ │
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│ │ │ │
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│ │ 1. Receive ClientHello & validate timestamp │ │
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│ │ 2. Derive PSK from ECDH + salt │ │
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│ │ 3. Perform Noise handshake │ │
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│ │ 4. Receive encrypted registration request │ │
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│ │ 5. Process registration (delegate to registration.rs) │ │
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│ │ 6. Send encrypted response │ │
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│ │ 7. Emit metrics & close │ │
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│ └────────────────────┬─────────────────────────────────────────┘ │
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│ │ │
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│ ┌────────────────────▼─────────────────────────────────────────┐ │
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│ │ Registration Processor (Business Logic) │ │
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│ │ gateway/src/node/lp_listener/registration.rs:136-288 │ │
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│ │ │ │
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│ │ Mode: dVPN Mode: Mixnet │ │
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│ │ ├─ register_wg_peer() ├─ (skip WireGuard) │ │
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│ │ ├─ credential_verification() ├─ credential_verification() │ │
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│ │ └─ return GatewayData └─ return bandwidth only │ │
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│ └────────┬───────────────────────────────┬─────────────────────┘ │
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│ │ │ │
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│ ┌────────▼───────────────────┐ ┌───────▼─────────────────────┐ │
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│ │ WireGuard Controller │ │ E-cash Verifier │ │
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│ │ (PeerControlRequest) │ │ (EcashManager trait) │ │
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│ │ │ │ │ │
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│ │ • Add/Remove WG peers │ │ • Verify BLS signature │ │
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│ │ • Manage peer lifecycle │ │ • Check nullifier spent │ │
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│ │ • Monitor bandwidth usage │ │ • Allocate bandwidth │ │
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│ └─────────────────────────────┘ └────────────────────────────┘ │
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│ │
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│ ┌─────────────────────────────────────────────────────────────┐ │
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│ │ GatewayStorage (Database) │ │
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│ │ │ │
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│ │ Tables: │ │
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│ │ • wireguard_peers (public_key, client_id, ticket_type) │ │
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│ │ • bandwidth (client_id, available) │ │
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│ │ • spent_credentials (nullifier, expiry) │ │
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│ └─────────────────────────────────────────────────────────────┘ │
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│ │
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└──────────────────────────────────────────────────────────────────────┘
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```
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---
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## Implementation Roadmap
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### ✅ Completed Components
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1. **Protocol Library** (`common/nym-lp/`)
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- Noise XKpsk3 implementation
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- PSK derivation (Blake3 KDF)
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- Replay protection with SIMD optimization
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- Message types and packet framing
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2. **Gateway Listener** (`gateway/src/node/lp_listener/`)
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- TCP accept loop with connection limits
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- Per-connection handler with lifecycle management
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- dVPN and Mixnet registration modes
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- Comprehensive metrics
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3. **Client Library** (`nym-registration-client/`)
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- Connection management with timeouts
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- Noise handshake as initiator
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- E-cash credential integration
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- Error handling and retries
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4. **Testing Tools** (`nym-gateway-probe/`)
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- LP-only test mode (`--only-lp-registration`)
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- Mock e-cash mode (`--use-mock-ecash`)
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- Detailed test results
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## Detailed Documentation
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### For Protocol Deep-Dive
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📄 **[LP_REGISTRATION_SEQUENCES.md](./LP_REGISTRATION_SEQUENCES.md)**
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- Complete sequence diagrams for all flows
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- Happy path with byte-level message formats
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- Error scenarios and recovery paths
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- Noise handshake details
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### For Architecture Understanding
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📄 **[LP_REGISTRATION_ARCHITECTURE.md](./LP_REGISTRATION_ARCHITECTURE.md)**
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- Component interaction diagrams
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- Data flow through gateway modules
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- Client-side architecture
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- State transitions
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---
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## Code Navigation
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### Key Entry Points
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| Component | File Path | Description |
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|-----------|-----------|-------------|
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| **Gateway Listener** | `gateway/src/node/lp_listener/mod.rs:226` | `LpListener::run()` - main loop |
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| **Connection Handler** | `gateway/src/node/lp_listener/handler.rs:101` | `LpConnectionHandler::handle()` - per-connection |
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| **Registration Logic** | `gateway/src/node/lp_listener/registration.rs:136` | `process_registration()` - business logic |
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| **Client Entry** | `nym-registration-client/src/lp_client/client.rs:39` | `LpRegistrationClient` struct |
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| **Protocol Core** | `common/nym-lp/src/state_machine.rs:96` | `LpStateMachine` - Noise protocol |
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| **Probe Test** | `nym-gateway-probe/src/lib.rs:861` | `lp_registration_probe()` - integration test |
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---
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## Metrics and Observability
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### Prometheus Metrics
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**Connection Metrics**:
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- `lp_connections_total{result="success|error"}` - Counter
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- `lp_active_lp_connections` - Gauge
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- `lp_connection_duration_seconds` - Histogram (buckets: 0.01, 0.1, 1, 5, 10, 30)
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**Handshake Metrics**:
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- `lp_handshakes_success` - Counter
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- `lp_handshakes_failed{reason="..."}` - Counter
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- `lp_handshake_duration_seconds` - Histogram
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**Registration Metrics**:
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- `lp_registration_attempts_total` - Counter
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- `lp_registration_success_total{mode="dvpn|mixnet"}` - Counter
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- `lp_registration_failed_total{reason="..."}` - Counter
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- `lp_registration_duration_seconds` - Histogram
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**Bandwidth Metrics**:
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- `lp_bandwidth_allocated_bytes_total` - Counter
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- `lp_credential_verification_success` - Counter
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- `lp_credential_verification_failed{reason="..."}` - Counter
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## Performance Characteristics
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### Latency Breakdown
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```
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Total Registration Time: ~221ms (typical)
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├─ TCP Connect: 10-20ms
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├─ Noise Handshake: 40-60ms (3 round-trips)
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│ ├─ ClientHello send: <5ms
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│ ├─ Msg 1 (-> e): <5ms
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│ ├─ Msg 2 (<- e,ee,s,es): 20-30ms (crypto ops)
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│ └─ Msg 3 (-> s,se,psk): 10-20ms
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├─ Registration Request: 100-150ms
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│ ├─ Request encrypt & send: <5ms
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│ ├─ Gateway processing: 90-140ms
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│ │ ├─ WireGuard peer setup: 20-40ms
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│ │ ├─ Database operations: 30-50ms
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│ │ ├─ E-cash verification: 40-60ms (or <1ms with mock)
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│ │ └─ Response preparation: <5ms
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│ └─ Response receive & decrypt: <5ms
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└─ Connection cleanup: <5ms
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```
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### Resource Usage
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- **Memory per session**: 144 bytes (state machine + replay window)
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- **Max concurrent connections**: 10,000 (configurable)
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- **CPU**: Minimal (ChaCha20 is efficient, SIMD optimizations)
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- **Database**: 3-5 queries per registration (indexed lookups) |