feat(protocols): refactor protocol utilities into centralized protocols module

ts/protocols/proxy/index.ts

@@ -0,0 +1,7 @@
+/**
+ * PROXY Protocol Module
+ * HAProxy PROXY protocol implementation
+ */
+
+export * from './types.js';
+export * from './parser.js';

ts/protocols/proxy/parser.ts

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+/**
+ * PROXY Protocol Parser
+ * Implementation of HAProxy PROXY protocol v1 (text format)
+ * Spec: https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
+ */
+
+import type { IProxyInfo, IProxyParseResult, TProxyProtocol } from './types.js';
+
+/**
+ * PROXY protocol parser
+ */
+export class ProxyProtocolParser {
+  static readonly PROXY_V1_SIGNATURE = 'PROXY ';
+  static readonly MAX_HEADER_LENGTH = 107; // Max length for v1 header
+  static readonly HEADER_TERMINATOR = '\r\n';
+  
+  /**
+   * Parse PROXY protocol v1 header from buffer
+   * Returns proxy info and remaining data after header
+   */
+  static parse(data: Buffer): IProxyParseResult {
+    // Check if buffer starts with PROXY signature
+    if (!data.toString('ascii', 0, 6).startsWith(this.PROXY_V1_SIGNATURE)) {
+      return {
+        proxyInfo: null,
+        remainingData: data
+      };
+    }
+    
+    // Find header terminator
+    const headerEndIndex = data.indexOf(this.HEADER_TERMINATOR);
+    if (headerEndIndex === -1) {
+      // Header incomplete, need more data
+      if (data.length > this.MAX_HEADER_LENGTH) {
+        // Header too long, invalid
+        throw new Error('PROXY protocol header exceeds maximum length');
+      }
+      return {
+        proxyInfo: null,
+        remainingData: data
+      };
+    }
+    
+    // Extract header line
+    const headerLine = data.toString('ascii', 0, headerEndIndex);
+    const remainingData = data.slice(headerEndIndex + 2); // Skip \r\n
+    
+    // Parse header
+    const parts = headerLine.split(' ');
+    
+    if (parts.length < 2) {
+      throw new Error(`Invalid PROXY protocol header format: ${headerLine}`);
+    }
+    
+    const [signature, protocol] = parts;
+    
+    // Validate protocol
+    if (!['TCP4', 'TCP6', 'UNKNOWN'].includes(protocol)) {
+      throw new Error(`Invalid PROXY protocol: ${protocol}`);
+    }
+    
+    // For UNKNOWN protocol, ignore addresses
+    if (protocol === 'UNKNOWN') {
+      return {
+        proxyInfo: {
+          protocol: 'UNKNOWN',
+          sourceIP: '',
+          sourcePort: 0,
+          destinationIP: '',
+          destinationPort: 0
+        },
+        remainingData
+      };
+    }
+    
+    // For TCP4/TCP6, we need all 6 parts
+    if (parts.length !== 6) {
+      throw new Error(`Invalid PROXY protocol header format: ${headerLine}`);
+    }
+    
+    const [, , srcIP, dstIP, srcPort, dstPort] = parts;
+    
+    // Validate and parse ports
+    const sourcePort = parseInt(srcPort, 10);
+    const destinationPort = parseInt(dstPort, 10);
+    
+    if (isNaN(sourcePort) || sourcePort < 0 || sourcePort > 65535) {
+      throw new Error(`Invalid source port: ${srcPort}`);
+    }
+    
+    if (isNaN(destinationPort) || destinationPort < 0 || destinationPort > 65535) {
+      throw new Error(`Invalid destination port: ${dstPort}`);
+    }
+    
+    // Validate IP addresses
+    const protocolType = protocol as TProxyProtocol;
+    if (!this.isValidIP(srcIP, protocolType)) {
+      throw new Error(`Invalid source IP for ${protocol}: ${srcIP}`);
+    }
+    
+    if (!this.isValidIP(dstIP, protocolType)) {
+      throw new Error(`Invalid destination IP for ${protocol}: ${dstIP}`);
+    }
+    
+    return {
+      proxyInfo: {
+        protocol: protocolType,
+        sourceIP: srcIP,
+        sourcePort,
+        destinationIP: dstIP,
+        destinationPort
+      },
+      remainingData
+    };
+  }
+  
+  /**
+   * Generate PROXY protocol v1 header
+   */
+  static generate(info: IProxyInfo): Buffer {
+    if (info.protocol === 'UNKNOWN') {
+      return Buffer.from(`PROXY UNKNOWN\r\n`, 'ascii');
+    }
+    
+    const header = `PROXY ${info.protocol} ${info.sourceIP} ${info.destinationIP} ${info.sourcePort} ${info.destinationPort}\r\n`;
+    
+    if (header.length > this.MAX_HEADER_LENGTH) {
+      throw new Error('Generated PROXY protocol header exceeds maximum length');
+    }
+    
+    return Buffer.from(header, 'ascii');
+  }
+  
+  /**
+   * Validate IP address format
+   */
+  static isValidIP(ip: string, protocol: TProxyProtocol): boolean {
+    if (protocol === 'TCP4') {
+      return this.isIPv4(ip);
+    } else if (protocol === 'TCP6') {
+      return this.isIPv6(ip);
+    }
+    return false;
+  }
+  
+  /**
+   * Check if string is valid IPv4
+   */
+  static isIPv4(ip: string): boolean {
+    const parts = ip.split('.');
+    if (parts.length !== 4) return false;
+    
+    for (const part of parts) {
+      const num = parseInt(part, 10);
+      if (isNaN(num) || num < 0 || num > 255 || part !== num.toString()) {
+        return false;
+      }
+    }
+    return true;
+  }
+  
+  /**
+   * Check if string is valid IPv6
+   */
+  static isIPv6(ip: string): boolean {
+    // Basic IPv6 validation
+    const ipv6Regex = /^(([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))$/;
+    return ipv6Regex.test(ip);
+  }
+  
+  /**
+   * Create a connection ID string for tracking
+   */
+  static createConnectionId(connectionInfo: {
+    sourceIp?: string;
+    sourcePort?: number;
+    destIp?: string;
+    destPort?: number;
+  }): string {
+    const { sourceIp, sourcePort, destIp, destPort } = connectionInfo;
+    return `${sourceIp}:${sourcePort}-${destIp}:${destPort}`;
+  }
+}

ts/protocols/proxy/types.ts

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+/**
+ * PROXY Protocol Type Definitions
+ * Based on HAProxy PROXY protocol specification
+ */
+
+/**
+ * PROXY protocol version
+ */
+export type TProxyProtocolVersion = 'v1' | 'v2';
+
+/**
+ * Connection protocol type
+ */
+export type TProxyProtocol = 'TCP4' | 'TCP6' | 'UNKNOWN';
+
+/**
+ * Interface representing parsed PROXY protocol information
+ */
+export interface IProxyInfo {
+  protocol: TProxyProtocol;
+  sourceIP: string;
+  sourcePort: number;
+  destinationIP: string;
+  destinationPort: number;
+}
+
+/**
+ * Interface for parse result including remaining data
+ */
+export interface IProxyParseResult {
+  proxyInfo: IProxyInfo | null;
+  remainingData: Buffer;
+}
+
+/**
+ * PROXY protocol v2 header format
+ */
+export interface IProxyV2Header {
+  signature: Buffer;
+  versionCommand: number;
+  family: number;
+  length: number;
+}
+
+/**
+ * Connection information for PROXY protocol
+ */
+export interface IProxyConnectionInfo {
+  sourceIp?: string;
+  sourcePort?: number;
+  destIp?: string;
+  destPort?: number;
+}