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/tools/Ruby/lib/ruby/1.8/ping.rb

http://github.com/agross/netopenspace
Ruby | 64 lines | 23 code | 4 blank | 37 comment | 2 complexity | 8fbc38c5da9f1a06d4f388db2e84b2fa MD5 | raw file
 1#
 2# = ping.rb: Check a host for upness
 3#
 4# Author:: Yukihiro Matsumoto
 5# Documentation:: Konrad Meyer
 6# 
 7# Performs the function of the basic network testing tool, ping.
 8# See: Ping.
 9#
10
11require 'timeout'
12require "socket"
13
14# 
15# Ping contains routines to test for the reachability of remote hosts.
16# Currently the only routine implemented is pingecho().
17#
18# Ping.pingecho uses a TCP echo (not an ICMP echo) to determine if the
19# remote host is reachable. This is usually adequate to tell that a remote
20# host is available to telnet, ftp, or ssh to.
21#
22# Warning: Ping.pingecho may block for a long time if DNS resolution is
23# slow. Requiring 'resolv-replace' allows non-blocking name resolution.
24#
25# Usage:
26# 
27#   require 'ping'
28#
29#   puts "'jimmy' is alive and kicking" if Ping.pingecho('jimmy', 10)
30#
31module Ping
32
33  # 
34  # Return true if we can open a connection to the hostname or IP address
35  # +host+ on port +service+ (which defaults to the "echo" port) waiting up
36  # to +timeout+ seconds.
37  #
38  # Example:
39  #
40  #   require 'ping'
41  #
42  #   Ping.pingecho "google.com", 10, 80
43  #
44  def pingecho(host, timeout=5, service="echo")
45    begin
46      timeout(timeout) do
47	s = TCPSocket.new(host, service)
48	s.close
49      end
50    rescue Errno::ECONNREFUSED
51      return true
52    rescue Timeout::Error, StandardError
53      return false
54    end
55    return true
56  end
57  module_function :pingecho
58end
59
60if $0 == __FILE__
61  host = ARGV[0]
62  host ||= "localhost"
63  printf("%s alive? - %s\n", host,  Ping::pingecho(host, 5))
64end