Use local variable instead of global

firewall

@@ -75,10 +75,10 @@ forward_port()
         return
     fi
 
-    source=$1
-    port=$2
-    destination=$3
-    proto=$4
+    local source=$1
+    local port=$2
+    local destination=$3
+    local proto=$4
 
     if echo "$destination" | grep -q ":"; then
         dest_ip=$(echo $destination | cut -d ":" -f1)
@@ -97,13 +97,13 @@ forward_port()
 open_port()
 {
     if [ $# == 4 ]; then
-        destination=$2
-        proto=$3
-        ports=$4
+        local destination=$2
+        local proto=$3
+        local ports=$4
     elif [ $# == 3 ]; then
-        destination=$IP
-        proto=$2
-        ports=$3
+        local destination=$IP
+        local proto=$2
+        local ports=$3
     else
         echo "!!! CRITICAL Open port bad syntax : $*"
         stop && exit 1
@@ -123,10 +123,10 @@ port_redirection()
         return
     fi
 
-    if=$1
-    proto=$2
-    srcport=$3
-    destport=$4
+    local if=$1
+    local proto=$2
+    local srcport=$3
+    local destport=$4
 
     echo "+ Redirect $if port $srcport to $destport for portocol $proto"
     iptables -t nat -A PREROUTING -i $if -p $proto --dport $srcport -j REDIRECT --to-port $destport
@@ -139,11 +139,11 @@ port_knocking()
         return
     fi
 
-    port=$1
-    knock_ports=$2
-    knock_number=$3
+    local port=$1
+    local knock_ports=$2
+    local knock_number=$3
+    local i=0
 
-    i=0
     for kport in $(echo $knock_ports | sed 's/,/ /g'); do
         ((i++))
         tock_number=$knock_number$i
@@ -253,10 +253,10 @@ start()
     done
 
     ## Port knocking
-    j=1
+    local i=1
     for args in "${PORT_KNOCK[@]}"; do
-        port_knocking $args $j
-        ((j++))
+        port_knocking $args $i
+        ((i++))
     done
 
     ## Port forwading