From 1cc154e1a25d4adaeb312370155417e910f20b1d Mon Sep 17 00:00:00 2001
From: tv <tv@shackspace.de>
Date: Wed, 20 May 2015 22:05:38 +0200
Subject: lib/net.sh: add net_netmask_to_prefix

---
 lib/net.sh | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 lib/net.sh

(limited to 'lib')

diff --git a/lib/net.sh b/lib/net.sh
new file mode 100644
index 00000000..518c955b
--- /dev/null
+++ b/lib/net.sh
@@ -0,0 +1,9 @@
+net_netmask_to_prefix() {(
+  binaryNetmask=$(echo $1 | sed 's/^/obase=2;/;s/\./;/g' | bc | tr -d \\n)
+  binaryPrefix=$(echo $binaryNetmask | sed -n 's/^\(1*\)0*$/\1/p')
+  if ! echo $binaryPrefix | grep -q .; then
+    echo $0: bad netmask: $netmask >&2
+    exit 4
+  fi
+  printf %s $binaryPrefix | tr -d 0 | wc -c
+)}
-- 
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