fix: mask_to_prefix function

Author: simonwalz

system/cuos/init.sh

@@ -197,18 +197,28 @@ mask_to_prefix() {
       echo ""
       return
     fi
-    # convert to binary and count bits
-    local bin
-    bin=$(printf '%08d' "$(bc <<< "obase=2;$oct")" 2>/dev/null || true)
-    # fallback if bc missing: use printf + awk (POSIX-friendly)
-    if [ -z "$bin" ] || [ "$bin" = "00000000" ]; then
-      # portable conversion
-      bin=$(printf '%08d' "$(echo "obase=2;$oct" | bc)" 2>/dev/null || printf '%08d' "$oct")
+    if [[ "$bits" != 0 && "$bits" != 8 && "$bits" != 16 && "$bits" != 24 && $oct != 0 ]]; then
+        # invalid/non-contiguous octet (e.g., 127, 3, 31)
+        echo ""
+        return
     fi
-    # Count ones
-    local ones
-    ones=$(echo -n "$bin" | tr -cd '1' | wc -c)
-    bits=$((bits + ones))
+    # count ones in the octet
+    case $oct in
+      0)  bits=$((bits+0)) ;;
+      128) bits=$((bits+1)) ;;
+      192) bits=$((bits+2)) ;;
+      224) bits=$((bits+3)) ;;
+      240) bits=$((bits+4)) ;;
+      248) bits=$((bits+5)) ;;
+      252) bits=$((bits+6)) ;;
+      254) bits=$((bits+7)) ;;
+      255) bits=$((bits+8)) ;;
+      *)
+        # invalid/non-contiguous octet (e.g., 127, 3, 31)
+        echo ""
+        return
+        ;;
+    esac
   done
   echo "$bits"
 }

system/cuos/init.test.sh

@@ -16,6 +16,29 @@ source "${SCRIPT_DIR}/lib-test.sh"
 # shellcheck source=/dev/null
 source "${SCRIPT_DIR}/init.sh"
 
+expect "mask_to_prefix cdr" \
+  "25" \
+  mask_to_prefix "25"
+
+expect "mask_to_prefix 16" "16" mask_to_prefix "255.255.0.0"
+expect "mask_to_prefix 17" "17" mask_to_prefix "255.255.128.0"
+expect "mask_to_prefix 18" "18" mask_to_prefix "255.255.192.0"
+expect "mask_to_prefix 19" "19" mask_to_prefix "255.255.224.0"
+expect "mask_to_prefix 20" "20" mask_to_prefix "255.255.240.0"
+expect "mask_to_prefix 21" "21" mask_to_prefix "255.255.248.0"
+expect "mask_to_prefix 22" "22" mask_to_prefix "255.255.252.0"
+expect "mask_to_prefix 23" "23" mask_to_prefix "255.255.254.0"
+expect "mask_to_prefix 24" "24" mask_to_prefix "255.255.255.0"
+expect "mask_to_prefix 25" "25" mask_to_prefix "255.255.255.128"
+expect "mask_to_prefix 26" "26" mask_to_prefix "255.255.255.192"
+expect "mask_to_prefix 27" "27" mask_to_prefix "255.255.255.224"
+expect "mask_to_prefix 28" "28" mask_to_prefix "255.255.255.240"
+expect "mask_to_prefix 29" "29" mask_to_prefix "255.255.255.248"
+expect "mask_to_prefix 30" "30" mask_to_prefix "255.255.255.252"
+expect "mask_to_prefix 31" "31" mask_to_prefix "255.255.255.254"
+expect "mask_to_prefix 32" "32" mask_to_prefix "255.255.255.255"
+
+expect "mask_to_prefix invalid" "" mask_to_prefix "255.255.252.128"
 
 export CONFIG_PATH="${SCRIPT_DIR}/init.test.system.json"
 export T_FILE_DOCKER_DAEMON="/dev/stdout"