#!/usr/bin/ruby

# Copyright (c) 2006 Peter Palfrader <peter@palfrader.org>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

require 'optparse'

NAGIOS_STATUS = { :OK => 0, :WARNING => 1, :CRITICAL => 2, :UNKNOWN => -1 };
@verbose = 0;
@additional_nameservers = []

def show_help(parser, code=0, io=STDOUT)
  program_name = File.basename($0, '.*')
  io.puts "Usage: #{program_name} [options]"
  io.puts parser.summarize
  exit(code)
end
ARGV.options do |opts|
        opts.on_tail("-h", "--help" , "Display this help screen")                { show_help(opts) }
        opts.parse!
end
show_help(ARGV.options, 1, STDERR) if ARGV.length > 0

unless File.executable?('/sbin/ip')
	puts "/sbin/ip is not executable"
	exit NAGIOS_STATUS[:UNKNOWN]
end

ip_output = nil
IO.popen("-") do |f|
	unless f  # child
		begin
			exec('/sbin/ip', 'route', 'show', '0.0.0.0/0')
		rescue => e
			puts "Cannot exec ip: "+e.message
			exit 1
		end
	end
	ip_output = f.readlines
end

if $? != 0
	puts "Child exited with non-zero exit code(%d): %s"%[$? >> 8, ip_output]
else
	if ip_output.length > 0
		puts "OK: %s" % [ip_output.join(' ')]
		exit NAGIOS_STATUS[:OK]
	else
		puts "CRITICAL: no default route found."
		exit NAGIOS_STATUS[:CRITICAL]
	end
end