package Net::Oping;

=head1 NAME

Net::Oping - ICMP latency measurement module using the oping library.

=head1 SYNOPSIS

  use Net::Oping;

  my $obj = Net::Oping->new ();
  $obj->host_add (qw(one.example.org two.example.org));
  
  my $ret = $obj->ping ();
  print "Latency to `one' is " . $ret->{'one.example.org'} . "\n";

=head1 DESCRIPTION

This Perl module is a high-level interface to the
L<oping library|http://verplant.org/liboping/>. Its purpose it to send C<ICMP
ECHO_REQUEST> packets (also known as "ping") to a host and measure the time
that elapses until the reception of an C<ICMP ECHO_REPLY> packet (also known as
"pong"). If no such packet is received after a certain timeout the host is considered to be unreachable.

The used C<oping> library supports "ping"ing multiple hosts in parallel and
works with IPv4 and IPv6 transparently. Other advanced features that are
provided by the underlying library, such as setting the data sent or
configuring the time of live (TTL) are not yet supported by this interface.

=cut

use 5.006;

use strict;
use warnings;

use Carp (qw(cluck confess));

our $VERSION = '1.01';

require XSLoader;
XSLoader::load ('Net::Oping', $VERSION);
return (1);

=head1 INTERFACE

The interface is kept simple and clean. First you need to create an object to
which you then add hosts. Using the C<ping> method you can request a latency
measurement and get the current values returned. If neccessary you can remove
hosts from the object, too.

The constructor and methods are defined as follows:

=over 4

=item my I<$obj> = Net::Oping-E<gt>B<new> ();

Creates and returns a new object.

=cut

sub new
{
  my $pkg = shift;
  my $ping_obj = _ping_construct ();

  my $obj = bless ({ c_obj => $ping_obj }, $pkg);
  return ($obj);
}

sub DESTROY
{
  my $obj = shift;
  _ping_destroy ($obj->{'c_obj'});
}

=item my I<$status> = I<$obj>-E<gt>B<timeout> (I<$timeout>);

Sets the timeout before a host is considered unreachable to I<$timeout>
seconds, which may be a floating point number to specify fractional seconds.

=cut

sub timeout
{
  my $obj = shift;
  my $timeout = shift;
  my $status;

  $status = _ping_setopt_timeout ($obj->{'c_obj'}, $timeout);
  if ($status != 0)
  {
    $obj->{'err_msg'} = "" . _ping_get_error ($obj->{'c_obj'});
    return;
  }

  return (1);
}

=item my I<$status> = I<$obj>-E<gt>B<bind> (I<$ip_addr>);

Sets the source IP-address to use. I<$ip_addr> must be a string containing an
IP-address, such as "192.168.0.1" or "2001:f00::1". As a side-effect this will
set the address-family (IPv4 or IPv6) to a fixed, value, too, for obvious
reasons.

=cut

sub bind
{
  my $obj = shift;
  my $addr = shift;
  my $status;

  $status = _ping_setopt_source ($obj->{'c_obj'}, $addr);
  if ($status != 0)
  {
    $obj->{'err_msg'} = "" . _ping_get_error ($obj->{'c_obj'});
    return;
  }

  return (1);
}

=item my I<$status> = I<$obj>-E<gt>B<host_add> (I<$host>, [I<$host>, ...]);

Adds one or more hosts to the Net::Oping-object I<$obj>. The number of
successfully added hosts is returned. If this number differs from the number of
hosts that were passed to the method you can use B<get_error> (see below) to
get the error message of the last failure.

=cut

sub host_add
{
  my $obj = shift;
  my $i;

  $i = 0;
  for (@_)
  {
    my $status = _ping_host_add ($obj->{'c_obj'}, $_);
    if ($status != 0)
    {
      $obj->{'err_msg'} = "" . _ping_get_error ($obj->{'c_obj'});
    }
    else
    {
      $i++;
    }
  }

  return ($i);
}

=item my I<$status> = I<$obj>-E<gt>B<host_remove> (I<$host>, [I<$host>, ...]);

Same semantic as B<host_add> but removes hosts.

=cut

sub host_remove
{
  my $obj = shift;
  my $i;

  $i = 0;
  for (@_)
  {
    my $status = _ping_host_remove ($obj->{'c_obj'}, $_);
    if ($status != 0)
    {
      $obj->{'err_msg'} = "" . _ping_get_error ($obj->{'c_obj'});
    }
    else
    {
      $i++;
    }
  }
  return ($i);
}

=item my I<$latency> = I<$obj>-E<gt>B<ping> ()

The central method of this module sends ICMP packets to the hosts and waits for
replies. The time it takes for replies to arrive is measured and returned.

The returned scalar is a hash reference where each host associated with the
I<$obj> object is a key and the associated value is the corresponding latency
in milliseconds. An example hash reference would be:

  $latency = { host1 => 51.143, host2 => undef, host3 => 54.697, ... };

If a value is C<undef>, as for "host2" in this example, the host has timed out
and considered unreachable.

=cut

sub ping
{
  my $obj = shift;
  my $iter;
  my $data = {};
  my $status;

  $status = _ping_send ($obj->{'c_obj'});
  if ($status < 0)
  {
    print "\$status = $status;\n";
    $obj->{'err_msg'} = "" . _ping_get_error ($obj->{'c_obj'});
    return;
  }

  $iter = _ping_iterator_get ($obj->{'c_obj'});
  while ($iter)
  {
    my $host = _ping_iterator_get_hostname ($iter);
    if (!$host)
    {
      $iter = _ping_iterator_next ($iter);
      next;
    }

    my $latency = _ping_iterator_get_latency ($iter);
    if ($latency < 0.0)
    {
      $latency = undef;
    }

    $data->{$host} = $latency;

    $iter = _ping_iterator_next ($iter);
  }

  return ($data);
}

=item my I<$errmsg> = I<$obj>-E<gt>B<get_error> ();

Returns the last error that occured.

=cut

sub get_error
{
  my $obj = shift;
  return ($obj->{'err_msg'} || 'Success');
}

=back

=head1 CAVEATS

The C<oping> library opens a raw socket to be able to send ICMP packets. On
most systems normal users are not allowed to do this. This is why on most
systems the L<ping(1)> utility is installed as SetUID-root. Since, when using
this module, no external process is spawned B<this> process needs the
appropriate permissions. This means that either your script has to run as
superuser or, under Linux, needs the C<CAP_NET_RAW> capability.

=head1 SEE ALSO

L<liboping(3)>

The C<liboping> homepage may be found at L<http://verplant.org/liboping/>.
Information about its mailing list may be found at
L<http://mailman.verplant.org/listinfo/liboping>.

=head1 AUTHOR

First XSE<nbsp>port by Olivier Fredj, extended XS functionality and high-level
Perl interface by Florian Forster.

=head1 COPYRIGHT AND LICENSE

Copyright (C) 2007 by Olivier Fredj E<lt>ofredjE<nbsp>atE<nbsp>proxad.netE<gt>

Copyright (C) 2008 by Florian Forster
E<lt>octoE<nbsp>atE<nbsp>verplant.orgE<gt>

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.7 or,
at your option, any later version of Perl 5 you may have available.

=cut

# vim: set shiftwidth=2 softtabstop=2 tabstop=8 :
