fix bug add rule

ubuntu_base/opportunistic_node.py

@@ -66,19 +66,20 @@ def process_packet(new_packet):
 
 
 def main():
-    for i in range(MIN_INTER_NUMBER, MAX_INTER_NUMBER):
-        inter_name = MARK_TO_INTERFACE[i]
-        rule_1 = f"sudo iptables -t mangle -A PREROUTING -i {inter_name} -j MARK --set-mark {i}"
     rule_check = "sudo iptables -C FORWARD -p tcp -j NFQUEUE --queue-num 1"
-        rule_2 = "sudo iptables -I FORWARD -p tcp -j NFQUEUE --queue-num 1"
-
     try:
         subprocess.run(rule_check, shell=True, check=True)
         print("Rule already exists, no need to add it.")
     except subprocess.CalledProcessError:
         try:
+            rule_1 = "sudo iptables -I FORWARD -p tcp -j NFQUEUE --queue-num 1"
             subprocess.run(rule_1, shell=True, check=True)
+
+            for i in range(MIN_INTER_NUMBER, MAX_INTER_NUMBER):
+                inter_name = MARK_TO_INTERFACE[i]
+                rule_2 = f"sudo iptables -t mangle -A PREROUTING -i {inter_name} -j MARK --set-mark {i}"
                 subprocess.run(rule_2, shell=True, check=True)
+
             print("Rule added successfully.")
         except subprocess.CalledProcessError as e:
             print(f"Failed to add the rule: {e}")