Simplify to detect and print handshake packet contents

- Detect TCP SYN packets and protocol-specific handshakes
- Print raw hex data in readable hex dump format with ASCII
- Show actual packet contents for signature analysis

lib/services/protocol_blocking_service.dart

@@ -177,53 +177,38 @@ class ProtocolBlockingService {
   }
   
   static Future<void> _analyzeFullPayload(String hexPacketLine, String peerIP) async {
-    print('🔍 DEEP PAYLOAD ANALYSIS for peer $peerIP');
-    
     // Extract hex bytes from tcpdump output
     final hexBytes = _extractHexBytes(hexPacketLine);
     
     if (hexBytes.isEmpty) {
-      print('❌ No hex payload data found');
       return;
     }
     
-    print('📊 Analyzing ${hexBytes.length} bytes of raw packet data');
+    // Check if this looks like a handshake (first packet of connection)
+    if (_isHandshakePacket(hexBytes)) {
+      print('🤝 HANDSHAKE DETECTED FROM $peerIP');
+      print('📦 RAW HEX DATA:');
       
-    // Convert hex to single string for nDPI analyzer
-    final hexString = hexBytes.join('');
+      // Print hex data in readable format
+      for (int i = 0; i < hexBytes.length; i += 16) {
+        final chunk = hexBytes.skip(i).take(16);
+        final hexLine = chunk.map((h) => h.padLeft(2, '0')).join(' ');
+        final asciiLine = chunk.map((h) {
+          final byte = int.parse(h, radix: 16);
+          return (byte >= 32 && byte <= 126) ? String.fromCharCode(byte) : '.';
+        }).join();
         
-    try {
-      // Use our nDPI analyzer for true protocol detection
-      final result = await Process.run('./protocol_analyzer', [hexString]);
-      
-      if (result.exitCode == 0) {
-        final output = result.stdout.toString().trim();
-        print('✅ nDPI DEEP ANALYSIS: $output');
-        
-        // Parse protocol from nDPI output
-        final protocolMatch = RegExp(r'"protocol":\s*"([^"]+)"').firstMatch(output);
-        final categoryMatch = RegExp(r'"category":\s*"([^"]+)"').firstMatch(output);
-        
-        if (protocolMatch != null) {
-          final protocol = protocolMatch.group(1) ?? 'Unknown';
-          final category = categoryMatch?.group(1) ?? 'Unknown';
-          
-          print('🎯 PAYLOAD PROTOCOL: $protocol (Category: $category)');
-          
-          if (_shouldBlockProtocol(protocol, category)) {
-            print('🚫 BLOCKING PAYLOAD-DETECTED PROTOCOL: $protocol');
-            // TODO: Implement actual blocking
-          } else {
-            print('✅ ALLOWING PAYLOAD-DETECTED PROTOCOL: $protocol');
-          }
-        }
-      } else {
-        print('⚠️ nDPI analyzer failed, using fallback payload analysis');
-        await _fallbackPayloadAnalysis(hexBytes, peerIP);
+        print('${i.toString().padLeft(4, '0')}: ${hexLine.padRight(48)} |$asciiLine|');
       }
-    } catch (e) {
-      print('❌ Error running nDPI analyzer: $e');
-      await _fallbackPayloadAnalysis(hexBytes, peerIP);
+      
+      // Also show raw ASCII if readable
+      final asciiData = _extractAsciiFromHex(hexBytes);
+      final readableAscii = asciiData.replaceAll(RegExp(r'[^\x20-\x7E]'), '.');
+      if (readableAscii.contains(RegExp(r'[a-zA-Z]'))) {
+        print('📝 ASCII: $readableAscii');
+      }
+      
+      print('═══════════════════════════════════════');
     }
   }
   
@@ -773,6 +758,51 @@ class ProtocolBlockingService {
     return false;
   }
   
+  static bool _isHandshakePacket(List<String> hexBytes) {
+    if (hexBytes.length < 20) return false;
+    
+    // Check for TCP SYN packet (handshake initiation)
+    if (hexBytes.length >= 34) {
+      // IP header is first 20 bytes, TCP header starts at byte 20
+      // TCP flags are at offset 33 (13th byte of TCP header)
+      try {
+        final tcpFlags = int.parse(hexBytes[33], radix: 16);
+        // Check for SYN flag (0x02) - indicates handshake
+        if (tcpFlags & 0x02 != 0) {
+          return true;
+        }
+      } catch (e) {
+        // Ignore parsing errors
+      }
+    }
+    
+    // Check for common handshake patterns in payload
+    final asciiData = _extractAsciiFromHex(hexBytes);
+    
+    // BitTorrent handshake starts with 19 + "BitTorrent protocol"
+    if (hexBytes.length >= 20 && hexBytes[0] == '13') {
+      return true;
+    }
+    
+    // HTTP requests
+    if (asciiData.startsWith('GET ') || asciiData.startsWith('POST ') || 
+        asciiData.startsWith('HEAD ') || asciiData.startsWith('PUT ')) {
+      return true;
+    }
+    
+    // TLS Client Hello
+    if (hexBytes.length >= 6 && hexBytes[0] == '16' && hexBytes[1] == '03') {
+      return true;
+    }
+    
+    // SSH handshake
+    if (asciiData.startsWith('SSH-')) {
+      return true;
+    }
+    
+    return false;
+  }
+  
   static List<String> _extractHexBytes(String tcpdumpOutput) {
     final hexPattern = RegExp(r'0x[0-9a-f]+:\s*([0-9a-f\s]+)', caseSensitive: false);
     final matches = hexPattern.allMatches(tcpdumpOutput);