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author | Nathan Lasseter <Nathan Lasseter nathan@bytemark.co.uk> | 2015-09-18 11:51:28 +0100 |
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committer | Nathan Lasseter <Nathan Lasseter nathan@bytemark.co.uk> | 2015-09-18 11:51:28 +0100 |
commit | b0a14e013b318fa87714414b8ece95780527bddf (patch) | |
tree | a9427383ab6e38a4421c9c4313043f6dfcb8e90e /genrdns |
Initial commit
Diffstat (limited to 'genrdns')
-rwxr-xr-x | genrdns | 48 |
1 files changed, 48 insertions, 0 deletions
@@ -0,0 +1,48 @@ +#!/usr/bin/env ruby + +def ip2num(ip) + ipa = ip.split(".").map(&:to_i) + return (ipa[0] * (256 ** 3)) + (ipa[1] * (256 ** 2)) + (ipa[2] * 256) + ipa[3] +end + +def num2ip(ipi) + outa = [] + outa[3] = ipi % 256 + outa[2] = (ipi / 256) % 256 + outa[1] = (ipi / (256 ** 2)) % 256 + outa[0] = (ipi / (256 ** 3)) % 256 + return outa.map(&:to_s).join(".") +end + +def boundarycheck(ip, cidr) + bound = 2**(32-cidr) + return (ip2num(ip) % bound) == 0 +end + +def addip(ip, x) + ipi = ip2num(ip) + ipi += x + return num2ip(ipi) +end + +def reverseip(ip) + return ip.split('.').reverse.join('.') +end + +if ARGV.length == 0 then + puts "Usage: genrdns ip[/cidr]" + exit +end + +IPCIDR = ARGV.shift.split("/") +IP = IPCIDR[0] +CIDR = IPCIDR[1].nil? ? 32 : IPCIDR[1].to_i + +unless boundarycheck(IP, CIDR) then + puts "Invalid CIDR Boundary" + exit 1 +end + +(2**(32-CIDR)).times do |x| + puts "#{reverseip(addip(IP, x))}.in-addr.arpa" +end |