# OSTP — Ospab Stealth Transport Protocol

[Русский язык](README.ru.md) · [Wiki](https://github.com/ospab/ostp/wiki) · [Contributing](CONTRIBUTING.md) · [Releases](https://github.com/ospab/ostp/releases)

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> A fast, custom encrypted transport protocol written in Rust.

**OSTP** (Ospab Stealth Transport Protocol) is a high-performance transport protocol. It implements a custom ARQ transport over UDP, as well as a UoT (UDP-over-TCP) mode. Every byte on the wire — including packet headers — is cryptographically indistinguishable from random noise, making it highly resistant to Deep Packet Inspection (DPI).

---

## Quick Install

### Linux
```bash
bash <(curl -Ls https://raw.githubusercontent.com/ospab/ostp/master/scripts/install.sh)
```

### Windows (PowerShell, run as Administrator)
```powershell
irm https://raw.githubusercontent.com/ospab/ostp/master/scripts/install.ps1 | iex
```

### Manual Download
Download pre-built binaries for your platform from [GitHub Releases](https://github.com/ospab/ostp/releases).

---

## Key Features

| Feature | Description |
|---------|-------------|
| **Full Traffic Obfuscation** | Every packet — including headers — is indistinguishable from random noise. Session IDs and nonces are masked with per-packet HMAC-derived keys. |
| **Noise Protocol Handshake** | `Noise_NNpsk0_25519_ChaChaPoly_BLAKE2s` — PSK-authenticated, forward-secret key exchange with no static identity exposure. |
| **Reliable UDP (ARQ)** | Selective ACK/NACK with rate-limited retransmission, configurable reorder buffer, and exponential backoff. |
| **Multiplexed Streams** | Multiple logical TCP streams over a single encrypted UDP session with per-stream flow control. |
| **Seamless Roaming** | Clients can switch networks (WiFi ↔ LTE) without session interruption — tracked by session-ID, not IP. |
| **Management API** | Built-in REST API for third-party panels (3x-ui, custom dashboards). Per-user stats, traffic limits, key CRUD. |
| **Fallback Server** | TCP fallback proxy to a web server — makes OSTP indistinguishable from nginx during active probing. |
| **Multi-Listener** | Bind to multiple addresses simultaneously (dual-stack IPv4/IPv6, multi-port). |
| **TUN Mode** | Full-system VPN via native `smoltcp` network stack without external dependencies. All traffic transparently routed through the tunnel. |
| **xHTTP Stealth (UoT)** | UDP-over-TCP tunnel that completely hides traffic. Since all data is fully encrypted and length-prefixed, it bypasses DPI filters that block unknown UDP traffic by riding over a plain TCP connection. |
| **Mobile & Web Apps** | Beautiful cross-platform mobile client (Flutter) and a modern Web Control Panel (React/Vite) for effortless server and client management. |
| **TURN Relay** | RFC 5766 TURN support for environments where direct UDP is blocked. |
| **Hot-Reload** | Runtime config reload without restart (access keys, exclusions, mux settings). |
| **Structured Logging** | `tracing`-based logging with `RUST_LOG` filtering. JSON/file/syslog output support. |
| **Cross-Platform** | Windows, Linux, macOS, Android, FreeBSD, MIPS, RISC-V. Single binary, no runtime dependencies. |

---

## Architecture

```mermaid
graph TD
    subgraph Client ["Client"]
        A[Browser / Apps] -->|SOCKS5 / HTTP| B(Bridge Multiplexer)
        TUN[TUN Interface] -->|IP Packets| B
        
        subgraph OSTPCoreClient ["OSTP Core Protocol"]
            B --> C{Protocol Machine}
            C -->|Noise Handshake| D[ChaCha20Poly1305 AEAD]
            D -->|Obfuscated UDP Payload| E((UDP Socket))
        end
    end

    E <==>|Encrypted & Obfuscated UDP Tunnel| F

    subgraph Server ["Server"]
        F((UDP Socket)) --> G{Dispatcher}
        
        subgraph OSTPCoreServer ["OSTP Core Backend"]
            G -->|Auth & Decrypt| H[Session & State Guard]
            H -->|TCP Stream| I[Relay Loop]
        end
        
        G -->|Active Probing / Unauth| FB[TCP Fallback Proxy]
        FB -->|Forward| NGINX[nginx / Caddy]
        
        H -->|Stats & Traffic| API[Management API]
        
        I -->|Outbound| WWW((Internet))
    end
```

---

## Quick Start

### 1. Generate config

```bash
# On your VPS (server):
./ostp --init server

# On your machine (client):
./ostp --init client
```

### 2. Edit config

**Server** — set your access keys:
```jsonc
{
  "mode": "server",
  "listen": "0.0.0.0:50000",
  "access_keys": ["YOUR_SECRET_KEY"],
  "api": { "enabled": true, "bind": "127.0.0.1:9090", "token": "admin-token" },
  "fallback": { "enabled": false, "listen": "0.0.0.0:443", "target": "127.0.0.1:8080" }
}
```

**Client** — point to your server:
```jsonc
{
  "mode": "client",
  "version": "0.3.1",
  "log": { "level": "info" },
  "inbounds": [
    { "type": "local_proxy", "tag": "socks-in", "protocol": "socks", "listen": "127.0.0.1", "port": 1088 },
    { "type": "tun", "tag": "tun-in", "auto_route": false, "mtu": 1140 }
  ],
  "outbounds": [
    {
      "type": "ostp",
      "tag": "proxy",
      "server": "YOUR_SERVER_IP",
      "port": 50000,
      "access_key": "YOUR_SECRET_KEY",
      "transport": { "type": "udp" }
    },
    { "type": "direct", "tag": "direct" },
    { "type": "block", "tag": "block" }
  ],
  "routing": {
    "rules": [
      { "domain_suffix": ["localhost"], "outbound": "direct" }
    ],
    "default_outbound": "proxy"
  }
}
```

> **Note:** Upgrading from v0.2.x? Read the [v0.3.1 Migration Guide](MIGRATION_V0_3_1.md).

### 3. Run

```bash
./ostp                        # Uses config.json in current directory
./ostp --config /path/to.json # Custom config path
./ostp --check                # Validate config without running
./ostp --generate-key         # Generate a new access key
./ostp --links                # Print client share links
```

### 4. Connect via share link (one-liner)
```bash
./ostp "ostp://ACCESS_KEY@server.com:50000?..."
```

> [!WARNING]
> Always wrap the `ostp://...` link in quotes (`"`) so your terminal doesn't misinterpret special characters like `&` or `?`.

---

## Management API

Built-in REST API for building panels and dashboards.

```bash
# Server status
curl -H "Authorization: Bearer mytoken" http://127.0.0.1:9090/api/server/status

# List all users with traffic stats  
curl -H "Authorization: Bearer mytoken" http://127.0.0.1:9090/api/users

# Create a user with 10GB traffic limit
curl -X POST -H "Authorization: Bearer mytoken" \
  -H "Content-Type: application/json" \
  -d '{"limit_bytes": 10737418240}' \
  http://127.0.0.1:9090/api/users
```

Full API reference: [Management API](https://github.com/ospab/ostp/wiki/Management-API)

---

## CLI Reference

```
ostp [OPTIONS] [URL]

Options:
  --config <PATH>        Config file path (default: config.json)
  --init <MODE>          Generate template config (server/client)
  --check                Validate configuration and exit
  -g, --generate-key     Generate a secure access key
  -c, --count <N>        Number of keys to generate (default: 1)
  --format <FMT>         Key format: hex, base64 (default: hex)
  --links                Print client share links from server config

Arguments:
  [URL]                  Connect via share link: ostp://KEY@HOST:PORT
```

---

## Protocol Summary

| Layer | Mechanism |
|-------|-----------|
| Key Exchange | Noise NNpsk0 (X25519 + ChaChaPoly + BLAKE2s) zero-RTT |
| Encryption | ChaCha20-Poly1305 AEAD per-packet |
| Header Obfuscation | HMAC-SHA256 derived per-packet mask |
| Reliability | Selective ACK with cumulative + SACK ranges |
| Retransmission | Rate-limited NACK + exponential backoff RTO |
| Keepalive | Ping/Pong with RTT measurement every 5s |

---

## Building from Source

```bash
# Prerequisites: Rust 1.75+
cargo build --release

# Cross-compile for Linux
cross build --release --target x86_64-unknown-linux-gnu

# Run tests
cargo test -p ostp-core -p ostp-server
```

---

## Documentation

- **[Wiki](https://github.com/ospab/ostp/wiki)** — Full documentation
- [Installation](https://github.com/ospab/ostp/wiki/Installation)
- [Configuration Reference](https://github.com/ospab/ostp/wiki/Configuration)
- [Management API](https://github.com/ospab/ostp/wiki/Management-API)
- [Protocol Design](https://github.com/ospab/ostp/wiki/Protocol-Design)
- [Building from Source](https://github.com/ospab/ostp/wiki/Building-from-Source)
- [FAQ](https://github.com/ospab/ostp/wiki/FAQ)

---

## License

Business Source License 1.1. Free for personal and non-commercial use.  
Converts to MIT License on May 14, 2030.

---

## Contact

- **Telegram**: [@ospab0](https://t.me/ospab0)
- **Email**: gvoprgrg@gmail.com