# @push.rocks/smartradius/server

> 🖥️ RADIUS Server Implementation - Full RFC 2865/2866 compliant authentication and accounting server

## Overview

This module provides a complete RADIUS server implementation supporting both authentication (RFC 2865) and accounting (RFC 2866) protocols. It handles PAP and CHAP authentication, accounting session tracking, and includes duplicate detection with response caching.

## Features

- ✅ **PAP Authentication** - Password Authentication Protocol with RFC-compliant encryption
- ✅ **CHAP Authentication** - Challenge-Handshake Authentication Protocol
- ✅ **Accounting** - Session start/stop/interim-update tracking
- ✅ **Duplicate Detection** - Automatic response caching for retransmitted requests
- ✅ **Per-Client Secrets** - Support for different shared secrets per NAS
- ✅ **Statistics** - Built-in request/response counters
- ✅ **VSA Support** - Vendor-Specific Attributes handling
- ✅ **Message-Authenticator** - HMAC-MD5 for EAP support

## Exports

### Classes

| Class | Description |
|-------|-------------|
| `RadiusServer` | Main server class handling authentication and accounting |
| `RadiusPacket` | Packet encoder/decoder for RADIUS protocol |
| `RadiusAttributes` | Attribute parsing and encoding utilities |
| `RadiusAuthenticator` | Cryptographic operations (PAP encryption, CHAP, authenticators) |
| `RadiusSecrets` | Client secret management |

### Interfaces (Server-Specific)

| Interface | Description |
|-----------|-------------|
| `IRadiusServerOptions` | Server configuration options |
| `IRadiusServerStats` | Server statistics counters |
| `IAuthenticationRequest` | Request context passed to auth handler |
| `IAuthenticationResponse` | Response from auth handler |
| `IAccountingRequest` | Request context passed to accounting handler |
| `IAccountingResponse` | Response from accounting handler |
| `TAuthenticationHandler` | Handler function type for authentication |
| `TAccountingHandler` | Handler function type for accounting |
| `TSecretResolver` | Function type for resolving client secrets |

## Usage

```typescript
import { RadiusServer, ERadiusCode } from '@push.rocks/smartradius';

const server = new RadiusServer({
  authPort: 1812,
  acctPort: 1813,
  defaultSecret: 'shared-secret',

  authenticationHandler: async (request) => {
    // PAP authentication
    if (request.password === 'correct-password') {
      return {
        code: ERadiusCode.AccessAccept,
        replyMessage: 'Welcome!',
        sessionTimeout: 3600,
      };
    }

    // CHAP authentication
    if (request.chapPassword && request.chapChallenge) {
      const isValid = RadiusAuthenticator.verifyChapResponse(
        request.chapPassword,
        request.chapChallenge,
        'expected-password'
      );
      if (isValid) {
        return { code: ERadiusCode.AccessAccept };
      }
    }

    return { code: ERadiusCode.AccessReject };
  },

  accountingHandler: async (request) => {
    console.log(`Session ${request.sessionId}: ${request.statusType}`);
    return { success: true };
  },
});

await server.start();
```

## Low-Level Packet Operations

```typescript
import {
  RadiusPacket,
  RadiusAuthenticator,
  RadiusAttributes,
  ERadiusAttributeType,
} from '@push.rocks/smartradius';

// Decode incoming packet
const packet = RadiusPacket.decodeAndParse(buffer);

// Encrypt PAP password
const encrypted = RadiusAuthenticator.encryptPassword(
  password, authenticator, secret
);

// Verify CHAP response
const valid = RadiusAuthenticator.verifyChapResponse(
  chapPassword, challenge, expectedPassword
);

// Create Vendor-Specific Attribute
const vsa = RadiusAttributes.createVendorAttribute(
  9,  // Cisco vendor ID
  1,  // Vendor type
  Buffer.from('value')
);
```

## Server Options

| Option | Type | Default | Description |
|--------|------|---------|-------------|
| `authPort` | number | 1812 | Authentication port |
| `acctPort` | number | 1813 | Accounting port |
| `bindAddress` | string | '0.0.0.0' | Address to bind to |
| `defaultSecret` | string | - | Default shared secret |
| `secretResolver` | function | - | Per-client secret resolver |
| `duplicateDetectionWindow` | number | 10000 | Duplicate detection window (ms) |
| `maxPacketSize` | number | 4096 | Maximum packet size |

## Re-exports

This module re-exports all types from `ts_shared` for convenience, so you can import everything from a single location.