fix(SniHandler): Improve TLS SNI session resumption handling: connections containing a session ticket are now only rejected when no SNI is present and allowSessionTicket is disabled. Updated return values and logging for clearer resumption detection.

ts/classes.snihandler.ts

@@ -372,6 +372,58 @@ export class SniHandler {
         pos += extensionLength;
       }
       
+      // Check if SNI is included
+      let hasSNI = false;
+      
+      // Reset position and scan again for SNI extension
+      pos = 5 + 1 + 3 + 2; // Reset to after handshake type, length and client version
+      pos += 32; // Skip client random
+      
+      if (pos + 1 <= buffer.length) {
+        const sessionIdLength = buffer[pos];
+        pos += 1 + sessionIdLength;
+        
+        // Skip cipher suites
+        if (pos + 2 <= buffer.length) {
+          const cipherSuitesLength = (buffer[pos] << 8) + buffer[pos + 1];
+          pos += 2 + cipherSuitesLength;
+          
+          // Skip compression methods
+          if (pos + 1 <= buffer.length) {
+            const compressionMethodsLength = buffer[pos];
+            pos += 1 + compressionMethodsLength;
+            
+            // Check for extensions
+            if (pos + 2 <= buffer.length) {
+              const extensionsLength = (buffer[pos] << 8) + buffer[pos + 1];
+              pos += 2;
+              
+              // Extensions end position
+              const extensionsEnd = pos + extensionsLength;
+              if (extensionsEnd <= buffer.length) {
+                // Scan for SNI 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_SNI_EXTENSION_TYPE) {
+                    hasSNI = true;
+                    log('Found SNI extension');
+                    break;
+                  }
+                  
+                  // Skip extension data
+                  pos += extensionLength;
+                }
+              }
+            }
+          }
+        }
+      }
+      
       // Consider it a resumption if any resumption mechanism is present
       const isResumption = hasSessionTicket || hasPSK || hasEarlyData || 
                          (hasNonEmptySessionId && !hasPSK); // Legacy resumption
@@ -381,13 +433,18 @@ export class SniHandler {
             (hasSessionTicket ? 'session ticket, ' : '') +
             (hasPSK ? 'PSK, ' : '') +
             (hasEarlyData ? 'early data, ' : '') +
-            (hasNonEmptySessionId ? 'session ID' : ''));
+            (hasNonEmptySessionId ? 'session ID' : '') +
+            (hasSNI ? ', with SNI' : ', without SNI'));
       }
       
-      return isResumption;
+      // Return an object with both flags
+      return { 
+        isResumption, 
+        hasSNI 
+      };
     } catch (error) {
       log(`Error checking for session resumption: ${error}`);
-      return false;
+      return { isResumption: false, hasSNI: false };
     }
   }