refactor: remove cidr_to_netmask(), set cidr directly

https://lists.debian.org/debian-boot/2012/09/msg00239.html

debi.sh

@@ -192,26 +192,6 @@ has_backports() {
     return 1
 }
 
-cidr_to_netmask() {
-    cidr=$1
-    mask=""
-
-    i=0
-    while [ $i -lt 4 ]; do
-        if [ $cidr -ge 8 ]; then
-            mask="${mask}255."
-            cidr=$((cidr - 8))
-        else
-            mask="${mask}$((256 - (1 << (8 - cidr))))."
-            cidr=0
-        fi
-        i=$((i + 1))
-    done
-
-    # Remove the trailing dot
-    echo "${mask%.}"
-}
-
 interface=auto
 ip=
 netmask=
@@ -298,7 +278,7 @@ while [ $# -gt 0 ]; do
             ip=$(ip r get 1.1.1.1 | awk '/src/ {print $7}')
             gateway=$(ip r get 1.1.1.1 | awk '/via/ {print $3}')
             _cidr=$(ip -o -f inet addr show | grep -w "$ip" | awk '{print $4}' | cut -d'/' -f2)
-            netmask=$(cidr_to_netmask "$_cidr")
+            ip="$ip/$_cidr"
             hostname=$(hostname)
             interface=$(ip r get 1.1.1.1 | awk '/dev/ {print $5}')
             ;;