#!/usr/bin/perl

use Net::IP qw(:PROC);

if ( $#ARGV != 0 ) {
	print STDERR "Usage:\n";
	print STDERR "\t$0 10.1.2.0/24\n";
	print STDERR "\t$0 '10.1.2.0 - 10.1.2.255'\n";
	print STDERR "\t$0 '10.1.2.0 + 255'\n";
	print STDERR "\t$0 dead:beef::/32\n";
	exit(1);
}

my $ip = new Net::IP(@ARGV[0]) or die (Net::IP::Error());

if ( $ip->version() != 4) { 
	die "I lied, I only support IPv4\n";
}

print STDERR ("IP      : ".$ip->ip()."\n");
#print STDERR ("Short   : ".$ip->short()."\n");
#print STDERR ("Int     : ".$ip->intip()."\n");
print STDERR ("Mask    : ".$ip->mask()."\n");
print STDERR ("Last    : ".$ip->last_ip()."\n");
#print STDERR ("Len : ".$ip->prefixlen()."\n");
#print STDERR ("Size: ".$ip->size()."\n");
#print STDERR ("Type: ".$ip->iptype()."\n");
print STDERR ("Reverse : ".$ip->reverse_ip()."\n");
#print STDERR ("Binary  : ".$ip->binip()."\n");

$gateway=($ip+1)->ip();
$mainip=($ip+2)->ip();
$netmask=$ip->mask();
$network=$ip->ip();
$alias_start=($ip+3)->ip();
$size=$ip->size();
my $a=ip_bintoip(ip_inttobin($ip->last_int()-1, $ip->version), $ip->version);
$ip->set($a, $ip->version) or die (Net::IP::Error());
$alias_end=$ip->ip();

## TODO: check if the range is too small to have aliases

## /etc/sysconfig/network-scripts/ifcfg-eth0
open IFCFG, "> ifcfg-eth0" or die "Can't open ifcfg-eth0: $!";
print IFCFG <<EOF;
# /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
IPADDR=$mainip
NETMASK=$netmask
NETWORK=$network
ONBOOT=yes
TYPE=Ethernet
GATEWAY=$gateway
EOF
close IFCFG;
print "Created ifcfg-eth0\n";

## /etc/sysconfig/network-scripts/ifcfg-eth0-range0
open IFCFG, "> ifcfg-eth0-range0" or die "Can't open ifcfg-eth0-range0: $!";
print IFCFG <<EOF;
# /etc/sysconfig/network-scripts/ifcfg-eth0-range0
DEVICE=eth0:1
BOOTPROTO=static
ONBOOT=yes
TYPE=Ethernet
IPADDR_START=$alias_start
IPADDR_END=$alias_end
CLONENUM_START=1
NETMASK=$netmask
EOF
close IFCFG;
print "Created ifcfg-eth0-range0\n";