diff --git a/lib/puppet/util/network_device/ipcalc.rb b/lib/puppet/util/network_device/ipcalc.rb
new file mode 100644
index 000000000..2b4f360b7
--- /dev/null
+++ b/lib/puppet/util/network_device/ipcalc.rb
@@ -0,0 +1,68 @@
+
+require 'puppet/util/network_device'
+module Puppet::Util::NetworkDevice::IPCalc
+
+  # This is a rip-off of authstore
+  Octet = '(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])'
+  IPv4 = "#{Octet}\.#{Octet}\.#{Octet}\.#{Octet}"
+  IPv6_full    = "_:_:_:_:_:_:_:_|_:_:_:_:_:_::_?|_:_:_:_:_::((_:)?_)?|_:_:_:_::((_:){0,2}_)?|_:_:_::((_:){0,3}_)?|_:_::((_:){0,4}_)?|_::((_:){0,5}_)?|::((_:){0,6}_)?"
+  IPv6_partial = "_:_:_:_:_:_:|_:_:_:_::(_:)?|_:_::(_:){0,2}|_::(_:){0,3}"
+  IP = "#{IPv4}|#{IPv6_full}".gsub(/_/,'([0-9a-fA-F]{1,4})').gsub(/\(/,'(?:')
+
+  def parse(value)
+    case value
+    when /^(#{IP})\/(\d+)$/  # 12.34.56.78/24, a001:b002::efff/120, c444:1000:2000::9:192.168.0.1/112
+      [$2.to_i,IPAddr.new($1)]
+    when /^(#{IP})$/           # 10.20.30.40,
+      value = IPAddr.new(value)
+      [bits(value.family),value]
+    end
+  end
+
+  def bits(family)
+    family == Socket::AF_INET6 ? 128 : 32
+  end
+
+  def fullmask(family)
+    (1 << bits(family)) - 1
+  end
+
+  def mask(family, length)
+    (1 << (bits(family) - length)) - 1
+  end
+
+  # returns ip address netmask from prefix length
+  def netmask(family, length)
+    IPAddr.new(fullmask(family) & ~mask(family, length) , family)
+  end
+
+  # returns an IOS wildmask
+  def wildmask(family, length)
+    IPAddr.new(mask(family, length) , family)
+  end
+
+  # returns ip address prefix length from netmask
+  def prefix_length(netmask)
+    mask_addr = netmask.to_i
+    return 0 if mask_addr == 0
+    length=32
+    if (netmask.ipv6?)
+      length=128
+    end
+
+    mask = mask_addr < 2**length ? length : 128
+
+    mask.times do
+        if ((mask_addr & 1) == 1)
+            break
+        end
+        mask_addr = mask_addr >> 1
+        mask = mask - 1
+    end
+    mask
+  end
+
+  def linklocal?(ip)
+  end
+
+end
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diff --git a/spec/unit/util/network_device/ipcalc_spec.rb b/spec/unit/util/network_device/ipcalc_spec.rb
new file mode 100644
index 000000000..6f55a66e4
--- /dev/null
+++ b/spec/unit/util/network_device/ipcalc_spec.rb
@@ -0,0 +1,63 @@
+#!/usr/bin/env ruby
+
+require File.dirname(__FILE__) + '/../../../spec_helper'
+
+require 'puppet/util/network_device/ipcalc'
+
+describe Puppet::Util::NetworkDevice::IPCalc do
+  class TestIPCalc
+    include Puppet::Util::NetworkDevice::IPCalc
+  end
+
+  before(:each) do
+    @ipcalc = TestIPCalc.new
+  end
+
+  describe "when parsing ip/prefix" do
+    it "should parse ipv4 without prefixes" do
+      @ipcalc.parse('127.0.0.1').should == [32,IPAddr.new('127.0.0.1')]
+    end
+
+    it "should parse ipv4 with prefixes" do
+      @ipcalc.parse('127.0.1.2/8').should == [8,IPAddr.new('127.0.1.2')]
+    end
+
+    it "should parse ipv6 without prefixes" do
+      @ipcalc.parse('FE80::21A:2FFF:FE30:ECF0').should == [128,IPAddr.new('FE80::21A:2FFF:FE30:ECF0')]
+    end
+
+    it "should parse ipv6 with prefixes" do
+      @ipcalc.parse('FE80::21A:2FFF:FE30:ECF0/56').should == [56,IPAddr.new('FE80::21A:2FFF:FE30:ECF0')]
+    end
+  end
+
+  describe "when building netmask" do
+    it "should produce the correct ipv4 netmask from prefix length" do
+      @ipcalc.netmask(Socket::AF_INET, 27).should == IPAddr.new('255.255.255.224')
+    end
+
+    it "should produce the correct ipv6 netmask from prefix length" do
+      @ipcalc.netmask(Socket::AF_INET6, 56).should == IPAddr.new('ffff:ffff:ffff:ff00::0')
+    end
+  end
+
+  describe "when building wildmask" do
+    it "should produce the correct ipv4 wildmask from prefix length" do
+      @ipcalc.wildmask(Socket::AF_INET, 27).should == IPAddr.new('0.0.0.31')
+    end
+
+    it "should produce the correct ipv6 wildmask from prefix length" do
+      @ipcalc.wildmask(Socket::AF_INET6, 126).should == IPAddr.new('::3')
+    end
+  end
+
+  describe "when computing prefix length from netmask" do
+    it "should produce the correct ipv4 prefix length" do
+      @ipcalc.prefix_length(IPAddr.new('255.255.255.224')).should == 27
+    end
+
+    it "should produce the correct ipv6 prefix length" do
+      @ipcalc.prefix_length(IPAddr.new('fffe::0')).should == 15
+    end
+  end
+end
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