fix: firewall shutdown on ctrl+c signal

Author: Satvik-Singh192

main.py

@@ -10,11 +10,15 @@
 import signal
 import traceback
 from pathlib import Path
+import threading
+import time
 
 # Add src directory to Python path for absolute imports
 current_dir = Path(__file__).parent
 src_dir = current_dir / 'src'
 sys.path.insert(0, str(src_dir))
+_SHUTDOWN_INITIATED = False
+_SHUTDOWN_LOCK = threading.Lock()
 
 try:
     from firewall.core import SimpleFirewall
@@ -148,15 +152,34 @@ def main():
 
         # Setup signal handlers for graceful shutdown
         def signal_handler(signum, frame):
-            print(f"\n{Fore.YELLOW}Signal {signum} received, shutting down...{Style.RESET_ALL}")
-            firewall.stop()
-            sys.exit(0)
-        
-        signal.signal(signal.SIGINT, signal_handler)
-        signal.signal(signal.SIGTERM, signal_handler)
-        
-        # Start the firewall
-        firewall.start()
+            """Enhanced signal handler with timeout and state tracking"""
+            global _SHUTDOWN_INITIATED
+            
+            with _SHUTDOWN_LOCK:
+                if _SHUTDOWN_INITIATED:
+                    print(f"\n{Fore.RED}Forced shutdown initiated...{Style.RESET_ALL}")
+                    os._exit(1)
+                    
+                _SHUTDOWN_INITIATED = True
+            
+            print(f"\n{Fore.YELLOW}Signal {signum} received, initiating graceful shutdown...{Style.RESET_ALL}")
+            
+            def force_shutdown():
+                time.sleep(5)
+                print(f"\n{Fore.RED}Graceful shutdown timeout, forcing exit...{Style.RESET_ALL}")
+                os._exit(1)
+            
+            force_thread = threading.Thread(target=force_shutdown, daemon=True)
+            force_thread.start()
+            
+            try:
+                if 'firewall' in locals():
+                    firewall.stop()
+                print(f"{Fore.GREEN}Firewall shutdown completed successfully.{Style.RESET_ALL}")
+                sys.exit(0)
+            except Exception as e:
+                print(f"{Fore.RED}Error during shutdown: {e}{Style.RESET_ALL}")
+                os._exit(1)
 
     except KeyboardInterrupt:
         print(f"\n{Fore.YELLOW}Interrupted by user{Style.RESET_ALL}")

src/firewall/core.py

@@ -4,7 +4,7 @@
 import time
 import signal
 import sys
-from scapy.all import sniff
+from scapy.all import sniff,AsyncSniffer
 from colorama import Fore, Style
 from typing import Optional
 
@@ -41,6 +41,9 @@ def __init__(self, interface: str = None, config_file: str = None):
         # Control flags
         self.running = False
         self._threads = []
+
+        self._sniffer = None
+        self._stop_event = threading.Event()
 
         self.logger.info("Simple Firewall initialized successfully")
 
@@ -167,26 +170,32 @@ def start(self):
             self.stop()
 
     def stop(self):
-        """Stop the firewall and cleanup"""
+        """Stop the firewall and cleanup - ENHANCED VERSION"""
+        if not self.running:
+            return
+            
         print(f"\n{Fore.YELLOW}Stopping firewall...{Style.RESET_ALL}")
         self.running = False
+        self._stop_event.set()
+        
+        if self._sniffer and self._sniffer.running:
+            self._sniffer.stop()
+        
+        timeout = 3.0
+        start_time = time.time()
 
-        # Wait for threads to finish (with timeout)
         for thread in self._threads:
             if thread.is_alive():
-                thread.join(timeout=2.0)
+                remaining_time = timeout - (time.time() - start_time)
+                if remaining_time > 0:
+                    thread.join(timeout=remaining_time)
 
-        # Display final stats
-        self._display_stats()
-        
-        # Cleanup firewall rules
-        print(f"{Fore.YELLOW}Cleaning up firewall rules...{Style.RESET_ALL}")
         cleaned_ips = self.blocker.cleanup_all_blocks()
         if cleaned_ips:
             self.logger.info(f"Cleaned up blocks for {len(cleaned_ips)} IPs")
 
-        print(f"{Fore.GREEN}Firewall stopped.{Style.RESET_ALL}")
-        self.logger.info("Simple Firewall stopped")
+        self._display_stats()
+        print(f"{Fore.GREEN}Firewall stopped successfully.{Style.RESET_ALL}")
 
     def get_status(self) -> dict:
         """Get current firewall status"""