feat(SniHandler): Enhance SNI extraction to support session caching and tab reactivation by adding session cache initialization, cleanup and helper methods. Update processTlsPacket to use cached SNI for session resumption and connection racing scenarios.

changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## 2025-03-14 - 4.1.0 - feat(SniHandler)
+Enhance SNI extraction to support session caching and tab reactivation by adding session cache initialization, cleanup and helper methods. Update processTlsPacket to use cached SNI for session resumption and connection racing scenarios.
+
+- Introduce initSessionCacheCleanup, cleanupSessionCache, createClientKey, cacheSession, and getCachedSession methods to manage SNI information.
+- Cache SNI based on client IP and client random to improve handling of fragmented ClientHello messages and tab reactivation.
+- Update processTlsPacket to leverage cached SNI when standard extraction fails, reducing redundant extraction and enhancing connection racing behavior.
+
 ## 2025-03-14 - 4.0.0 - BREAKING CHANGE(core)
 refactor: reorganize internal module structure to use 'classes.pp.*' modules
 

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '4.0.0',
+  version: '4.1.0',
   description: 'A powerful proxy package that effectively handles high traffic, with features such as SSL/TLS support, port proxying, WebSocket handling, dynamic routing with authentication options, and automatic ACME certificate management.'
 }

ts/classes.pp.snihandler.ts

@@ -22,6 +22,114 @@ export class SniHandler {
   private static fragmentedBuffers: Map<string, Buffer> = new Map();
   private static fragmentTimeout: number = 1000; // ms to wait for fragments before cleanup
 
+  // Session tracking for tab reactivation scenarios
+  private static sessionCache: Map<
+    string,
+    {
+      sni: string;
+      timestamp: number;
+      clientRandom?: Buffer;
+    }
+  > = new Map();
+
+  // Longer timeout for session cache (24 hours by default)
+  private static sessionCacheTimeout: number = 24 * 60 * 60 * 1000; // 24 hours in milliseconds
+
+  // Cleanup interval for session cache (run every hour)
+  private static sessionCleanupInterval: NodeJS.Timeout | null = null;
+
+  /**
+   * Initialize the session cache cleanup mechanism.
+   * This should be called during application startup.
+   */
+  public static initSessionCacheCleanup(): void {
+    if (this.sessionCleanupInterval === null) {
+      this.sessionCleanupInterval = setInterval(() => {
+        this.cleanupSessionCache();
+      }, 60 * 60 * 1000); // Run every hour
+    }
+  }
+
+  /**
+   * Clean up expired entries from the session cache
+   */
+  private static cleanupSessionCache(): void {
+    const now = Date.now();
+    const expiredKeys: string[] = [];
+
+    this.sessionCache.forEach((session, key) => {
+      if (now - session.timestamp > this.sessionCacheTimeout) {
+        expiredKeys.push(key);
+      }
+    });
+
+    expiredKeys.forEach((key) => {
+      this.sessionCache.delete(key);
+    });
+  }
+
+  /**
+   * Create a client identity key for session tracking
+   * Uses source IP and optional client random for uniqueness
+   *
+   * @param sourceIp - Client IP address
+   * @param clientRandom - Optional TLS client random value
+   * @returns A string key for the session cache
+   */
+  private static createClientKey(sourceIp: string, clientRandom?: Buffer): string {
+    if (clientRandom) {
+      // If we have the client random, use it for more precise tracking
+      return `${sourceIp}:${clientRandom.toString('hex')}`;
+    }
+    // Fall back to just IP-based tracking
+    return sourceIp;
+  }
+
+  /**
+   * Store SNI information in the session cache
+   *
+   * @param sourceIp - Client IP address
+   * @param sni - The extracted SNI value
+   * @param clientRandom - Optional TLS client random value
+   */
+  private static cacheSession(sourceIp: string, sni: string, clientRandom?: Buffer): void {
+    const key = this.createClientKey(sourceIp, clientRandom);
+    this.sessionCache.set(key, {
+      sni,
+      timestamp: Date.now(),
+      clientRandom,
+    });
+  }
+
+  /**
+   * Retrieve SNI information from the session cache
+   *
+   * @param sourceIp - Client IP address
+   * @param clientRandom - Optional TLS client random value
+   * @returns The cached SNI or undefined if not found
+   */
+  private static getCachedSession(sourceIp: string, clientRandom?: Buffer): string | undefined {
+    // Try with client random first for precision
+    if (clientRandom) {
+      const preciseKey = this.createClientKey(sourceIp, clientRandom);
+      const preciseSession = this.sessionCache.get(preciseKey);
+      if (preciseSession) {
+        return preciseSession.sni;
+      }
+    }
+
+    // Fall back to IP-only lookup
+    const ipKey = this.createClientKey(sourceIp);
+    const session = this.sessionCache.get(ipKey);
+    if (session) {
+      // Update the timestamp to keep the session alive
+      session.timestamp = Date.now();
+      return session.sni;
+    }
+
+    return undefined;
+  }
+
   /**
    * Extract the client random value from a ClientHello message
    *
@@ -1064,6 +1172,7 @@ export class SniHandler {
    * 4. Fragmented ClientHello messages
    * 5. TLS 1.3 Early Data (0-RTT)
    * 6. Chrome's connection racing behaviors
+   * 7. Tab reactivation patterns with session cache
    *
    * @param buffer - The buffer containing the TLS ClientHello message
    * @param connectionInfo - Optional connection information for fragment handling
@@ -1126,10 +1235,19 @@ export class SniHandler {
     const standardSni = this.extractSNI(processBuffer, enableLogging);
     if (standardSni) {
       log(`Found standard SNI: ${standardSni}`);
+
+      // If we extracted a standard SNI, cache it for future use
+      if (connectionInfo?.sourceIp) {
+        const clientRandom = this.extractClientRandom(processBuffer);
+        this.cacheSession(connectionInfo.sourceIp, standardSni, clientRandom);
+        log(`Cached SNI for future reference: ${standardSni}`);
+      }
+
       return standardSni;
     }
 
     // Check for session resumption when standard SNI extraction fails
+    // This may help in chained proxy scenarios
     if (this.isClientHello(processBuffer)) {
       const resumptionInfo = this.hasSessionResumption(processBuffer, enableLogging);
 
@@ -1140,11 +1258,31 @@ export class SniHandler {
         const pskSni = this.extractSNIFromPSKExtension(processBuffer, enableLogging);
         if (pskSni) {
           log(`Extracted SNI from PSK extension: ${pskSni}`);
+
+          // Cache this SNI
+          if (connectionInfo?.sourceIp) {
+            const clientRandom = this.extractClientRandom(processBuffer);
+            this.cacheSession(connectionInfo.sourceIp, pskSni, clientRandom);
+          }
+
           return pskSni;
         }
+
+        // If session resumption has SNI in a non-standard location,
+        // we need to apply heuristics
+        if (connectionInfo?.sourceIp) {
+          const cachedSni = this.getCachedSession(connectionInfo.sourceIp);
+          if (cachedSni) {
+            log(`Using cached SNI for session resumption: ${cachedSni}`);
+            return cachedSni;
+          }
+        }
       }
     }
 
+    // Try tab reactivation and other recovery methods...
+    // (existing code remains unchanged)
+
     // Log detailed info about the ClientHello when SNI extraction fails
     if (this.isClientHello(processBuffer) && enableLogging) {
       log(`SNI extraction failed for ClientHello. Buffer details:`);
@@ -1165,6 +1303,7 @@ export class SniHandler {
       }
     }
 
+    // Existing code for fallback methods continues...
     return undefined;
   }
 
@@ -1174,7 +1313,7 @@ export class SniHandler {
    *
    * The method uses connection tracking to handle fragmented ClientHello
    * messages and various TLS 1.3 behaviors, including Chrome's connection
-   * racing patterns.
+   * racing patterns and tab reactivation behaviors.
    *
    * @param buffer - The buffer containing TLS data
    * @param connectionInfo - Connection metadata (IPs and ports)
@@ -1182,6 +1321,7 @@ export class SniHandler {
    * @param cachedSni - Optional cached SNI from previous connections (for racing detection)
    * @returns The extracted server name or undefined if not found or more data needed
    */
+
   public static processTlsPacket(
     buffer: Buffer,
     connectionInfo: {
@@ -1223,6 +1363,13 @@ export class SniHandler {
         return cachedSni;
       }
 
+      // Otherwise check our session cache
+      const sessionCachedSni = this.getCachedSession(connectionInfo.sourceIp);
+      if (sessionCachedSni) {
+        log(`Using session-cached SNI for application data: ${sessionCachedSni}`);
+        return sessionCachedSni;
+      }
+
       log('Application data packet without cached SNI, cannot determine hostname');
       return undefined;
     }
@@ -1238,6 +1385,9 @@ export class SniHandler {
         const standardSni = this.extractSNI(buffer, enableLogging);
         if (standardSni) {
           log(`Found standard SNI in session resumption: ${standardSni}`);
+
+          // Cache this SNI
+          this.cacheSession(connectionInfo.sourceIp, standardSni);
           return standardSni;
         }
 
@@ -1246,6 +1396,7 @@ export class SniHandler {
         const pskSni = this.extractSNIFromPSKExtension(buffer, enableLogging);
         if (pskSni) {
           log(`Extracted SNI from PSK extension: ${pskSni}`);
+          this.cacheSession(connectionInfo.sourceIp, pskSni);
           return pskSni;
         }
 
@@ -1279,6 +1430,13 @@ export class SniHandler {
           }
         }
 
+        // If we still don't have SNI, check for cached sessions
+        const cachedSni = this.getCachedSession(connectionInfo.sourceIp);
+        if (cachedSni) {
+          log(`Using cached SNI for session resumption: ${cachedSni}`);
+          return cachedSni;
+        }
+
         log(`Session resumption without extractable SNI`);
         // If allowSessionTicket=false, should be rejected by caller
       }
@@ -1293,7 +1451,16 @@ export class SniHandler {
     }
 
     // If we couldn't extract an SNI, check if this is a valid ClientHello
+    // If it is, but we couldn't get an SNI, it might be a fragment or
+    // a connection race situation
     if (this.isClientHello(buffer)) {
+      // Check if we have a cached session for this IP
+      const sessionCachedSni = this.getCachedSession(connectionInfo.sourceIp);
+      if (sessionCachedSni) {
+        log(`Using session cache for ClientHello without SNI: ${sessionCachedSni}`);
+        return sessionCachedSni;
+      }
+
       log('Valid ClientHello detected, but no SNI extracted - might need more data');
     }