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Net::Oping.3pm

NAME

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

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";
 
 

DESCRIPTION

This Perl module is a high-level interface to the oping library <http://verplant.org/liboping/>. Its purpose it to send "ICMP ECHO_REQUEST" packets (also known as ``ping'') to a host and measure the time that elapses until the reception of an "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 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, are not yet supported by this interface.

INTERFACE

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

The constructor and methods are defined as follows:

$obj = Net::Oping->new ();

Creates and returns a new object.

$status = $obj->timeout ($timeout);

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

$status = $obj->ttl ($ttl);

Sets the Time to Live (TTL) of outgoing packets. $ttl must be in the range 1 ... 255. Returns true when successful and false when an error occurred.

$status = $obj->bind ($ip_addr);

Sets the source IP-address to use. $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.

$status = $obj->device ($device);

Sets the network device used for communication. This may not be supported on all platforms.

Requires liboping 1.3 or later.

$status = $obj->host_add ($host, [$host, ...]);

Adds one or more hosts to the Net::Oping-object $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 get_error (see below) to get the error message of the last failure.

$status = $obj->host_remove ($host, [$host, ...]);

Same semantic as host_add but removes hosts.

$latency = $obj->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 $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 "undef", as for ``host2'' in this example, the host has timed out and considered unreachable.

$dropped = $obj->get_dropped ()

Returns a hash reference holding the number of ``drops'' (echo requests which were not answered in time) for each host. An example return values would be:

   $droprate = { host1 => 0, host2 => 3, host3 => undef, ... };
 
 

Hosts to which no data has been sent yet will return "undef" (``host3'' in thie example).

$ttl = $obj->get_recv_ttl ()

Returns a hash reference holding the Time to Live (TTL) of the last received packet for each host. An example return value would be:

   $ttl = { host1 => 60, host2 => 41, host3 => 243, ... };
 
 

To signal an invalid or unavailable TTL, a negative number is returned.

$errmsg = $obj->get_error ();

Returns the last error that occurred.

CAVEATS

The 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 ping(1) utility is installed as SetUID-root. Since, when using this module, no external process is spawned this process needs the appropriate permissions. This means that either your script has to run as superuser or, under Linux, needs the "CAP_NET_RAW" capability.

SEE ALSO

liboping(3)

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

AUTHORS

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

COPYRIGHT AND LICENSE

Copyright (C) 2007 by Olivier Fredj <ofredj at proxad.net>

Copyright (C) 2008,2009 by Florian Forster <octo at verplant.org>

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.

Please note that liboping is licensed under the GPLv2. Derived works of both, Net::Oping and liboping, (i. e. binary packages) may therefore be subject to stricter licensing terms than the source code of this package.