sandbox listing network interfaces

module Castoro
  module IfConfig

    # This module works with both CentOS and OpenSolaris.

    IFCONFIG_COMMAND = '/sbin/ifconfig -a'

    def network_interfaces
      Hash.new.tap do |h|
        IO.popen IFCONFIG_COMMAND do |pipe|
          while line = pipe.gets do
            line =~ /\A(\w+)\W/ and h[ (dev = $1) ] = {}
            line =~ /inet\D+(\d+\.\d+\.\d+\.\d+)/  and h[dev][:inet] = $1
            line =~ /(?:Bcast|broadcast)\D+(\d+\.\d+\.\d+\.\d+)/ and h[dev][:broadcast] = $1
            line =~ /Mask\D+(\d+\.\d+\.\d+\.\d+)/  and h[dev][:netmask] = $1
            line =~ /netmask\s+([0-9a-f]+)/        and h[dev][:netmask] = convert_hex_into_dec($1)
          end
        end
      end
    end

    private

    def convert_hex_into_dec value
      n = value.hex
      d = n & 0xff
      c = (n >> 8) & 0xff
      b = (n >> 8) & 0xff
      a = (n >> 8) & 0xff
      sprintf "%d.%d.%d.%d", a, b, c, d
    end

    module_function :network_interfaces, :convert_hex_into_dec
  end

end

if $0 == __FILE__
  module Castoro
    IfConfig.network_interfaces.each do |k, v|
      print "#{k} => #{v}\n"
    end
  end
end

__END__

centos$ /usr/local/bin/ruby list_nic.rb
eth0 => {:inet=>"192.168.223.10", :broadcast=>"192.168.223.255", :netmask=>"255.255.255.0"}
eth1 => {:inet=>"192.168.224.10", :broadcast=>"192.168.224.255", :netmask=>"255.255.255.0"}
lo => {:inet=>"127.0.0.1", :netmask=>"255.0.0.0"}
...

opensolaris$ /usr/local/bin/ruby list_nic.rb
lo0 => {}
rge0 => {:inet=>"192.168.223.20", :broadcast=>"192.168.223.255", :netmask=>"255.255.255.0"}
rge1 => {:inet=>"192.168.224.20", :broadcast=>"192.168.224.255", :netmask=>"255.255.255.0"}