From 7cf2c21798b537a5553ecc23df5ce8cfda631e9c Mon Sep 17 00:00:00 2001

From: Daniel Molkentin <dmolkentin@suse.com>

Date: Tue, 25 Apr 2017 15:25:20 +0200

Subject: [PATCH] mkinitrd-suse.sh: Fix prefix calculation

The previous algorithm was incorrect and would return

incorrect results e.g. for a /20 mask. Also gets rid

of an undocumented depencency on bc(1).

Reference: bsc#1035743

---

 mkinitrd-suse.sh | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mkinitrd-suse.sh b/mkinitrd-suse.sh

index bc49d731..d9de81b9 100755

--- a/mkinitrd-suse.sh

+++ b/mkinitrd-suse.sh

@@ -104,7 +104,7 @@ calc_netmask() {

     local prefix=$1

     [ -z "$prefix" ] && return

-    mask=$(echo "(2 ^ 32) - (2 ^ $prefix)" | bc -l)

+    mask=$(( 0xffffffff << (32 - $prefix) ))

     byte1=$(( mask >> 24 ))

     byte2=$(( mask >> 16 ))

     byte3=$(( mask >> 8 ))