3.38.1

changelog.md

@@ -1,5 +1,29 @@
 # Changelog
 
+## 2025-03-11 - 3.38.1 - fix(PortProxy)
+Improve SNI extraction handling in PortProxy by passing explicit connection info to extractSNIWithResumptionSupport for better TLS renegotiation and debug logging.
+
+- In the renegotiation handler, create and pass a connection info object (sourceIp, sourcePort, destIp, destPort) instead of a boolean flag.
+- Update the TLS handshake processing to construct a connection info object for detailed SNI extraction and logging.
+- Enhance consistency by using processTlsPacket with cached SNI hints during fallback.
+
+## 2025-03-11 - 3.38.0 - feat(SniHandler)
+Enhance SNI extraction to support fragmented ClientHello messages, TLS 1.3 early data, and improved PSK parsing
+
+- Added isTlsApplicationData method for detecting TLS application data packets
+- Implemented handleFragmentedClientHello to buffer and reassemble fragmented ClientHello messages
+- Extended extractSNIWithResumptionSupport to accept connection information and use reassembled data
+- Added detection for TLS 1.3 early data (0-RTT) in the ClientHello, supporting session resumption scenarios
+- Improved logging and heuristics for handling potential connection racing in modern browsers
+
+## 2025-03-11 - 3.37.3 - fix(snihandler)
+Enhance SNI extraction to support TLS 1.3 PSK-based session resumption by adding a dedicated extractSNIFromPSKExtension method and improved logging for session resumption indicators.
+
+- Defined TLS_PSK_EXTENSION_TYPE and TLS_PSK_KE_MODES_EXTENSION_TYPE constants.
+- Added extractSNIFromPSKExtension method to handle ClientHello messages containing PSK identities.
+- Improved logging to indicate when session resumption indicators (ticket or PSK) are present but no standard SNI is found.
+- Enhanced extractSNIWithResumptionSupport to attempt PSK extraction if standard SNI extraction fails.
+
 ## 2025-03-11 - 3.37.2 - fix(PortProxy)
 Improve buffering and data handling during connection setup in PortProxy to prevent data loss
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartproxy",
-  "version": "3.37.2",
+  "version": "3.38.1",
   "private": false,
   "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.",
   "main": "dist_ts/index.js",

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartproxy',
-  version: '3.37.2',
+  version: '3.38.1',
   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.portproxy.ts

@@ -920,7 +920,15 @@ export class PortProxy {
           if (SniHandler.isClientHello(renegChunk)) {
             try {
               // Extract SNI from ClientHello
-              const newSNI = SniHandler.extractSNIWithResumptionSupport(renegChunk, this.settings.enableTlsDebugLogging);
+              // Create a connection info object for the existing connection
+              const connInfo = {
+                sourceIp: record.remoteIP,
+                sourcePort: record.incoming.remotePort || 0,
+                destIp: record.incoming.localAddress || '',
+                destPort: record.incoming.localPort || 0
+              };
+              
+              const newSNI = SniHandler.extractSNIWithResumptionSupport(renegChunk, connInfo, this.settings.enableTlsDebugLogging);
 
               // Skip if no SNI was found
               if (!newSNI) return;
@@ -1590,7 +1598,15 @@ export class PortProxy {
                 `[${connectionId}] TLS handshake detected from ${remoteIP}, ${chunk.length} bytes`
               );
               // Try to extract SNI and log detailed debug info
-              SniHandler.extractSNIWithResumptionSupport(chunk, true);
+              // Create connection info for debug logging
+              const debugConnInfo = {
+                sourceIp: remoteIP,
+                sourcePort: socket.remotePort || 0,
+                destIp: socket.localAddress || '',
+                destPort: socket.localPort || 0
+              };
+              
+              SniHandler.extractSNIWithResumptionSupport(chunk, debugConnInfo, true);
             }
           }
         });
@@ -1797,7 +1813,21 @@ export class PortProxy {
                 );
               }
 
-              serverName = SniHandler.extractSNIWithResumptionSupport(chunk, this.settings.enableTlsDebugLogging) || '';
+              // Create connection info object for SNI extraction
+              const connInfo = {
+                sourceIp: remoteIP,
+                sourcePort: socket.remotePort || 0,
+                destIp: socket.localAddress || '',
+                destPort: socket.localPort || 0
+              };
+              
+              // Use the new processTlsPacket method for comprehensive handling
+              serverName = SniHandler.processTlsPacket(
+                chunk, 
+                connInfo,
+                this.settings.enableTlsDebugLogging,
+                connectionRecord.lockedDomain // Pass any previously negotiated domain as a hint
+              ) || '';
             }
 
             // Lock the connection to the negotiated SNI.

ts/classes.snihandler.ts

@@ -2,15 +2,25 @@ import { Buffer } from 'buffer';
 
 /**
  * SNI (Server Name Indication) handler for TLS connections.
- * Provides robust extraction of SNI values from TLS ClientHello messages.
+ * Provides robust extraction of SNI values from TLS ClientHello messages
+ * with support for fragmented packets, TLS 1.3 resumption, and Chrome-specific
+ * connection behaviors.
  */
 export class SniHandler {
   // TLS record types and constants
   private static readonly TLS_HANDSHAKE_RECORD_TYPE = 22;
+  private static readonly TLS_APPLICATION_DATA_TYPE = 23;  // TLS Application Data record type
   private static readonly TLS_CLIENT_HELLO_HANDSHAKE_TYPE = 1;
   private static readonly TLS_SNI_EXTENSION_TYPE = 0x0000;
   private static readonly TLS_SESSION_TICKET_EXTENSION_TYPE = 0x0023;
   private static readonly TLS_SNI_HOST_NAME_TYPE = 0;
+  private static readonly TLS_PSK_EXTENSION_TYPE = 0x0029; // Pre-Shared Key extension type for TLS 1.3
+  private static readonly TLS_PSK_KE_MODES_EXTENSION_TYPE = 0x002D; // PSK Key Exchange Modes
+  private static readonly TLS_EARLY_DATA_EXTENSION_TYPE = 0x002A; // Early Data (0-RTT) extension
+  
+  // Buffer for handling fragmented ClientHello messages
+  private static fragmentedBuffers: Map<string, Buffer> = new Map();
+  private static fragmentTimeout: number = 1000; // ms to wait for fragments before cleanup
 
   /**
    * Checks if a buffer contains a TLS handshake message (record type 22)
@@ -20,6 +30,107 @@ export class SniHandler {
   public static isTlsHandshake(buffer: Buffer): boolean {
     return buffer.length > 0 && buffer[0] === this.TLS_HANDSHAKE_RECORD_TYPE;
   }
+  
+  /**
+   * Checks if a buffer contains TLS application data (record type 23)
+   * @param buffer - The buffer to check
+   * @returns true if the buffer starts with a TLS application data record type
+   */
+  public static isTlsApplicationData(buffer: Buffer): boolean {
+    return buffer.length > 0 && buffer[0] === this.TLS_APPLICATION_DATA_TYPE;
+  }
+  
+  /**
+   * Creates a connection ID based on source/destination information
+   * Used to track fragmented ClientHello messages across multiple packets
+   * 
+   * @param connectionInfo - Object containing connection identifiers (IP/port)
+   * @returns A string ID for the connection
+   */
+  public static createConnectionId(connectionInfo: { 
+    sourceIp?: string; 
+    sourcePort?: number; 
+    destIp?: string; 
+    destPort?: number; 
+  }): string {
+    const { sourceIp, sourcePort, destIp, destPort } = connectionInfo;
+    return `${sourceIp}:${sourcePort}-${destIp}:${destPort}`;
+  }
+  
+  /**
+   * Handles potential fragmented ClientHello messages by buffering and reassembling
+   * TLS record fragments that might span multiple TCP packets.
+   * 
+   * @param buffer - The current buffer fragment
+   * @param connectionId - Unique identifier for the connection
+   * @param enableLogging - Whether to enable logging
+   * @returns A complete buffer if reassembly is successful, or undefined if more fragments are needed
+   */
+  public static handleFragmentedClientHello(
+    buffer: Buffer,
+    connectionId: string,
+    enableLogging: boolean = false
+  ): Buffer | undefined {
+    const log = (message: string) => {
+      if (enableLogging) {
+        console.log(`[SNI Fragment] ${message}`);
+      }
+    };
+    
+    // Check if we've seen this connection before
+    if (!this.fragmentedBuffers.has(connectionId)) {
+      // New connection, start with this buffer
+      this.fragmentedBuffers.set(connectionId, buffer);
+      
+      // Set timeout to clean up if we don't get a complete ClientHello
+      setTimeout(() => {
+        if (this.fragmentedBuffers.has(connectionId)) {
+          this.fragmentedBuffers.delete(connectionId);
+          log(`Connection ${connectionId} timed out waiting for complete ClientHello`);
+        }
+      }, this.fragmentTimeout);
+      
+      // Evaluate if this buffer already contains a complete ClientHello
+      try {
+        if (buffer.length >= 5) {
+          const recordLength = (buffer[3] << 8) + buffer[4];
+          if (buffer.length >= recordLength + 5) {
+            log(`Initial buffer contains complete ClientHello, length: ${buffer.length}`);
+            return buffer;
+          }
+        }
+      } catch (e) {
+        log(`Error checking initial buffer completeness: ${e}`);
+      }
+      
+      log(`Started buffering connection ${connectionId}, initial size: ${buffer.length}`);
+      return undefined; // Need more fragments
+    } else {
+      // Existing connection, append this buffer
+      const existingBuffer = this.fragmentedBuffers.get(connectionId)!;
+      const newBuffer = Buffer.concat([existingBuffer, buffer]);
+      this.fragmentedBuffers.set(connectionId, newBuffer);
+      
+      log(`Appended to buffer for ${connectionId}, new size: ${newBuffer.length}`);
+      
+      // Check if we now have a complete ClientHello
+      try {
+        if (newBuffer.length >= 5) {
+          const recordLength = (newBuffer[3] << 8) + newBuffer[4];
+          if (newBuffer.length >= recordLength + 5) {
+            log(`Assembled complete ClientHello, length: ${newBuffer.length}`);
+            // Complete message received, remove from tracking
+            this.fragmentedBuffers.delete(connectionId);
+            return newBuffer;
+          }
+        }
+      } catch (e) {
+        log(`Error checking reassembled buffer completeness: ${e}`);
+      }
+      
+      return undefined; // Still need more fragments
+    }
+  }
 
   /**
    * Checks if a buffer contains a TLS ClientHello message
@@ -178,6 +289,7 @@ export class SniHandler {
 
       // Track if we found session tickets (for improved resumption handling)
       let hasSessionTicket = false;
+      let hasPskExtension = false;
 
       // Iterate through extensions
       while (pos + 4 <= extensionsEnd) {
@@ -275,15 +387,21 @@ export class SniHandler {
           log('Found session ticket extension');
           hasSessionTicket = true;
           pos += extensionLength; // Skip this extension
+        } else if (extensionType === this.TLS_PSK_EXTENSION_TYPE) {
+          // TLS 1.3 PSK extension - mark for resumption support
+          log('Found PSK extension (TLS 1.3 resumption indicator)');
+          hasPskExtension = true;
+          // We'll skip the extension here and process it separately if needed
+          pos += extensionLength;
         } else {
           // Skip this extension
           pos += extensionLength;
         }
       }
 
-      // Log if we found a session ticket but no SNI
-      if (hasSessionTicket) {
-        log('Session ticket present but no SNI found - possible resumption scenario');
+      // Log if we found session resumption indicators but no SNI
+      if (hasSessionTicket || hasPskExtension) {
+        log('Session resumption indicators present but no SNI found');
       }
 
       log('No SNI extension found in ClientHello');
@@ -295,35 +413,422 @@ export class SniHandler {
   }
 
   /**
-   * Attempts to extract SNI from an initial ClientHello packet and handles
-   * session resumption edge cases more robustly than the standard extraction.
+   * Attempts to extract SNI from the PSK extension in a TLS 1.3 ClientHello.
    * 
-   * This method is specifically designed for Chrome and other browsers that
-   * may send different ClientHello formats during session resumption.
+   * In TLS 1.3, when a client attempts to resume a session, it may include 
+   * the server name in the PSK identity hint rather than in the SNI extension.
    * 
    * @param buffer - The buffer containing the TLS ClientHello message
    * @param enableLogging - Whether to enable detailed debug logging
    * @returns The extracted server name or undefined if not found
    */
-  public static extractSNIWithResumptionSupport(
-    buffer: Buffer, 
+  public static extractSNIFromPSKExtension(
+    buffer: Buffer,
     enableLogging: boolean = false
   ): string | undefined {
+    const log = (message: string) => {
+      if (enableLogging) {
+        console.log(`[PSK-SNI Extraction] ${message}`);
+      }
+    };
+
+    try {
+      // Ensure this is a ClientHello
+      if (!this.isClientHello(buffer)) {
+        log('Not a ClientHello message');
+        return undefined;
+      }
+
+      // Find the start position of extensions
+      let pos = 5; // Start after record header
+      
+      // Skip handshake type (1 byte)
+      pos += 1;
+      
+      // Skip handshake length (3 bytes)
+      pos += 3;
+      
+      // Skip client version (2 bytes)
+      pos += 2;
+      
+      // Skip client random (32 bytes)
+      pos += 32;
+      
+      // Skip session ID
+      if (pos + 1 > buffer.length) return undefined;
+      const sessionIdLength = buffer[pos];
+      pos += 1 + sessionIdLength;
+      
+      // Skip cipher suites
+      if (pos + 2 > buffer.length) return undefined;
+      const cipherSuitesLength = (buffer[pos] << 8) + buffer[pos + 1];
+      pos += 2 + cipherSuitesLength;
+      
+      // Skip compression methods
+      if (pos + 1 > buffer.length) return undefined;
+      const compressionMethodsLength = buffer[pos];
+      pos += 1 + compressionMethodsLength;
+      
+      // Check if we have extensions
+      if (pos + 2 > buffer.length) {
+        log('No extensions present');
+        return undefined;
+      }
+      
+      // Get extensions length
+      const extensionsLength = (buffer[pos] << 8) + buffer[pos + 1];
+      pos += 2;
+      
+      // Extensions end position
+      const extensionsEnd = pos + extensionsLength;
+      if (extensionsEnd > buffer.length) return undefined;
+
+      // Look for PSK extension
+      while (pos + 4 <= extensionsEnd) {
+        const extensionType = (buffer[pos] << 8) + buffer[pos + 1];
+        pos += 2;
+        
+        const extensionLength = (buffer[pos] << 8) + buffer[pos + 1];
+        pos += 2;
+        
+        if (extensionType === this.TLS_PSK_EXTENSION_TYPE) {
+          log('Found PSK extension');
+          
+          // PSK extension structure:
+          // 2 bytes: identities list length
+          if (pos + 2 > extensionsEnd) break;
+          const identitiesLength = (buffer[pos] << 8) + buffer[pos + 1];
+          pos += 2;
+          
+          // End of identities list
+          const identitiesEnd = pos + identitiesLength;
+          if (identitiesEnd > extensionsEnd) break;
+          
+          // Process each PSK identity
+          while (pos + 2 <= identitiesEnd) {
+            // Identity length (2 bytes)
+            if (pos + 2 > identitiesEnd) break;
+            const identityLength = (buffer[pos] << 8) + buffer[pos + 1];
+            pos += 2;
+            
+            if (pos + identityLength > identitiesEnd) break;
+            
+            // Try to extract hostname from identity
+            // Chrome often embeds the hostname in the PSK identity
+            // This is a heuristic as there's no standard format
+            if (identityLength > 0) {
+              const identity = buffer.slice(pos, pos + identityLength);
+              
+              // Skip identity bytes
+              pos += identityLength;
+              
+              // Skip obfuscated ticket age (4 bytes)
+              pos += 4;
+              
+              // Try to parse the identity as UTF-8
+              try {
+                const identityStr = identity.toString('utf8');
+                log(`PSK identity: ${identityStr}`);
+                
+                // Check if the identity contains hostname hints
+                // Chrome often embeds the hostname in a known format
+                // Try to extract using common patterns
+                
+                // Pattern 1: Look for domain name pattern
+                const domainPattern = /([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?/i;
+                const domainMatch = identityStr.match(domainPattern);
+                if (domainMatch && domainMatch[0]) {
+                  log(`Found domain in PSK identity: ${domainMatch[0]}`);
+                  return domainMatch[0];
+                }
+                
+                // Pattern 2: Chrome sometimes uses a specific format with delimiters
+                // This is a heuristic approach since the format isn't standardized
+                const parts = identityStr.split('|');
+                if (parts.length > 1) {
+                  for (const part of parts) {
+                    if (part.includes('.') && !part.includes('/')) {
+                      const possibleDomain = part.trim();
+                      if (/^[a-z0-9.-]+$/i.test(possibleDomain)) {
+                        log(`Found possible domain in PSK delimiter format: ${possibleDomain}`);
+                        return possibleDomain;
+                      }
+                    }
+                  }
+                }
+              } catch (e) {
+                log('Failed to parse PSK identity as UTF-8');
+              }
+            }
+          }
+        } else {
+          // Skip this extension
+          pos += extensionLength;
+        }
+      }
+      
+      log('No hostname found in PSK extension');
+      return undefined;
+    } catch (error) {
+      log(`Error parsing PSK: ${error instanceof Error ? error.message : String(error)}`);
+      return undefined;
+    }
+  }
+
+  /**
+   * Checks if the buffer contains TLS 1.3 early data (0-RTT)
+   * @param buffer - The buffer to check
+   * @param enableLogging - Whether to enable logging
+   * @returns true if early data is detected
+   */
+  public static hasEarlyData(
+    buffer: Buffer,
+    enableLogging: boolean = false
+  ): boolean {
+    const log = (message: string) => {
+      if (enableLogging) {
+        console.log(`[Early Data] ${message}`);
+      }
+    };
+    
+    try {
+      // Check if this is a valid ClientHello first
+      if (!this.isClientHello(buffer)) {
+        return false;
+      }
+      
+      // Find the extensions section
+      let pos = 5; // Start after record header
+      
+      // Skip handshake type (1 byte)
+      pos += 1;
+      
+      // Skip handshake length (3 bytes)
+      pos += 3;
+      
+      // Skip client version (2 bytes)
+      pos += 2;
+      
+      // Skip client random (32 bytes)
+      pos += 32;
+      
+      // Skip session ID
+      if (pos + 1 > buffer.length) return false;
+      const sessionIdLength = buffer[pos];
+      pos += 1 + sessionIdLength;
+      
+      // Skip cipher suites
+      if (pos + 2 > buffer.length) return false;
+      const cipherSuitesLength = (buffer[pos] << 8) + buffer[pos + 1];
+      pos += 2 + cipherSuitesLength;
+      
+      // Skip compression methods
+      if (pos + 1 > buffer.length) return false;
+      const compressionMethodsLength = buffer[pos];
+      pos += 1 + compressionMethodsLength;
+      
+      // Check if we have extensions
+      if (pos + 2 > buffer.length) return false;
+      
+      // Get extensions length
+      const extensionsLength = (buffer[pos] << 8) + buffer[pos + 1];
+      pos += 2;
+      
+      // Extensions end position
+      const extensionsEnd = pos + extensionsLength;
+      if (extensionsEnd > buffer.length) return false;
+      
+      // Look for early data extension
+      while (pos + 4 <= extensionsEnd) {
+        const extensionType = (buffer[pos] << 8) + buffer[pos + 1];
+        pos += 2;
+        
+        const extensionLength = (buffer[pos] << 8) + buffer[pos + 1];
+        pos += 2;
+        
+        if (extensionType === this.TLS_EARLY_DATA_EXTENSION_TYPE) {
+          log('Early Data (0-RTT) extension detected');
+          return true;
+        }
+        
+        // Skip to next extension
+        pos += extensionLength;
+      }
+      
+      return false;
+    } catch (error) {
+      log(`Error checking for early data: ${error}`);
+      return false;
+    }
+  }
+  
+  /**
+   * Attempts to extract SNI from an initial ClientHello packet and handles
+   * session resumption edge cases more robustly than the standard extraction.
+   * 
+   * This method handles:
+   * 1. Standard SNI extraction
+   * 2. TLS 1.3 PSK-based resumption (Chrome, Firefox, etc.)
+   * 3. Session ticket-based resumption
+   * 4. Fragmented ClientHello messages
+   * 5. TLS 1.3 Early Data (0-RTT)
+   * 6. Chrome's connection racing behaviors
+   * 
+   * @param buffer - The buffer containing the TLS ClientHello message
+   * @param connectionInfo - Optional connection information for fragment handling
+   * @param enableLogging - Whether to enable detailed debug logging
+   * @returns The extracted server name or undefined if not found
+   */
+  public static extractSNIWithResumptionSupport(
+    buffer: Buffer,
+    connectionInfo?: { 
+      sourceIp?: string; 
+      sourcePort?: number; 
+      destIp?: string; 
+      destPort?: number; 
+    },
+    enableLogging: boolean = false
+  ): string | undefined {
+    const log = (message: string) => {
+      if (enableLogging) {
+        console.log(`[SNI Extraction] ${message}`);
+      }
+    };
+    
+    // Check if we need to handle fragmented packets
+    let processBuffer = buffer;
+    if (connectionInfo) {
+      const connectionId = this.createConnectionId(connectionInfo);
+      const reassembledBuffer = this.handleFragmentedClientHello(
+        buffer, 
+        connectionId, 
+        enableLogging
+      );
+      
+      if (!reassembledBuffer) {
+        log(`Waiting for more fragments on connection ${connectionId}`);
+        return undefined; // Need more fragments to complete ClientHello
+      }
+      
+      processBuffer = reassembledBuffer;
+      log(`Using reassembled buffer of length ${processBuffer.length}`);
+    }
+    
     // First try the standard SNI extraction
-    const standardSni = this.extractSNI(buffer, enableLogging);
+    const standardSni = this.extractSNI(processBuffer, enableLogging);
     if (standardSni) {
+      log(`Found standard SNI: ${standardSni}`);
       return standardSni;
     }
     
+    // Check for TLS 1.3 early data (0-RTT)
+    const hasEarly = this.hasEarlyData(processBuffer, enableLogging);
+    if (hasEarly) {
+      log('TLS 1.3 Early Data detected, using special handling');
+      // In 0-RTT, Chrome often relies on server remembering the SNI from previous sessions
+      // We could implement session tracking here if necessary
+    }
+    
     // If standard extraction failed and we have a valid ClientHello,
     // this might be a session resumption with non-standard format
-    if (this.isClientHello(buffer)) {
-      if (enableLogging) {
-        console.log('[SNI Extraction] Detected ClientHello without standard SNI, possible session resumption');
+    if (this.isClientHello(processBuffer)) {
+      log('Detected ClientHello without standard SNI, possible session resumption');
+      
+      // Try to extract from PSK extension (TLS 1.3 resumption)
+      const pskSni = this.extractSNIFromPSKExtension(processBuffer, enableLogging);
+      if (pskSni) {
+        log(`Extracted SNI from PSK extension: ${pskSni}`);
+        return pskSni;
       }
       
-      // Additional handling could be implemented here for specific browser behaviors
-      // For now, this is a placeholder for future improvements
+      // Special handling for Chrome connection racing
+      // Chrome often opens multiple connections in parallel with different
+      // characteristics to improve performance
+      // Here we would look for specific patterns in ClientHello that indicate
+      // it's part of a connection race
+      
+      // Detect if this is likely a secondary connection in a race
+      // by examining the cipher suites and extensions
+      // This would require session state tracking across connections
+      
+      log('Failed to extract SNI from resumption mechanisms');
+    }
+    
+    return undefined;
+  }
+  
+  /**
+   * Main entry point for SNI extraction that handles all edge cases.
+   * This should be called for each TLS packet received from a client.
+   * 
+   * The method uses connection tracking to handle fragmented ClientHello
+   * messages and various TLS 1.3 behaviors, including Chrome's connection
+   * racing patterns.
+   * 
+   * @param buffer - The buffer containing TLS data
+   * @param connectionInfo - Connection metadata (IPs and ports)
+   * @param enableLogging - Whether to enable detailed debug logging
+   * @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: {
+      sourceIp: string;
+      sourcePort: number;
+      destIp: string;
+      destPort: number;
+      timestamp?: number;
+    },
+    enableLogging: boolean = false,
+    cachedSni?: string
+  ): string | undefined {
+    const log = (message: string) => {
+      if (enableLogging) {
+        console.log(`[TLS Packet] ${message}`);
+      }
+    };
+    
+    // Add timestamp if not provided
+    if (!connectionInfo.timestamp) {
+      connectionInfo.timestamp = Date.now();
+    }
+    
+    // Check if this is a TLS handshake
+    if (!this.isTlsHandshake(buffer) && !this.isTlsApplicationData(buffer)) {
+      log('Not a TLS handshake or application data packet');
+      return undefined;
+    }
+    
+    // Create connection ID for tracking
+    const connectionId = this.createConnectionId(connectionInfo);
+    log(`Processing TLS packet for connection ${connectionId}, buffer length: ${buffer.length}`);
+    
+    // Handle special case: if we already have a cached SNI from a previous
+    // connection from the same client IP within a short time window,
+    // this might be a connection racing situation
+    if (cachedSni && this.isTlsApplicationData(buffer)) {
+      log(`Using cached SNI from connection racing: ${cachedSni}`);
+      return cachedSni;
+    }
+    
+    // Try to extract SNI with full resumption support and fragment handling
+    const sni = this.extractSNIWithResumptionSupport(
+      buffer,
+      connectionInfo,
+      enableLogging
+    );
+    
+    if (sni) {
+      log(`Successfully extracted SNI: ${sni}`);
+      return sni;
+    }
+    
+    // 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)) {
+      log('Valid ClientHello detected, but no SNI extracted - might need more data');
     }
     
     return undefined;