NAME

IO::Interface - Perl extension for access to network card configuration information

SYNOPSIS

# ======================
# the new, preferred API
# ======================

use IO::Interface::Simple;

my $if1   = IO::Interface::Simple->new('eth0');
my $if2   = IO::Interface::Simple->new_from_address('127.0.0.1');
my $if3   = IO::Interface::Simple->new_from_index(1);

my @interfaces = $IO::Interface::Simple->interfaces;

for my $if (@interfaces) {
   print "interface = $if\n";
   print "addr =      ",$s->address,"\n",
         "broadcast = ",$s->broadcast,"\n",
         "netmask =   ",$s->netmask,"\n",
         "dstaddr =   ",$s->dstaddr,"\n",
         "hwaddr =    ",$s->hwaddr,"\n",
         "mtu =       ",$s->mtu,"\n",
         "metric =    ",$s->metric,"\n",
         "index =     ",$s->index,"\n";

   print "is running\n"     if $if->is_running;
   print "is broadcast\n"   if $if->is_broadcast;
   print "is p-to-p\n"      if $if->is_pt2pt;
   print "is loopback\n"    if $if->is_loopback;
   print "is promiscuous\n" if $if->is_promiscuous;
   print "is multicast\n"   if $if->is_multicast;
   print "is notrailers\n"  if $if->is_notrailers;
   print "is noarp\n"       if $if->is_noarp;
 }


 # ===========
 # the old API
 # ===========

 use IO::Socket;
 use IO::Interface qw(:flags);

 my $s = IO::Socket::INET->new(Proto => 'udp');
 my @interfaces = $s->if_list;

 for my $if (@interfaces) {
   print "interface = $if\n";
   my $flags = $s->if_flags($if);
   print "addr =      ",$s->if_addr($if),"\n",
         "broadcast = ",$s->if_broadcast($if),"\n",
         "netmask =   ",$s->if_netmask($if),"\n",
         "dstaddr =   ",$s->if_dstaddr($if),"\n",
         "hwaddr =    ",$s->if_hwaddr($if),"\n";

   print "is running\n"     if $flags & IFF_RUNNING;
   print "is broadcast\n"   if $flags & IFF_BROADCAST;
   print "is p-to-p\n"      if $flags & IFF_POINTOPOINT;
   print "is loopback\n"    if $flags & IFF_LOOPBACK;
   print "is promiscuous\n" if $flags & IFF_PROMISC;
   print "is multicast\n"   if $flags & IFF_MULTICAST;
   print "is notrailers\n"  if $flags & IFF_NOTRAILERS;
   print "is noarp\n"       if $flags & IFF_NOARP;
 }

 my $interface = $s->addr_to_interface('127.0.0.1');

DESCRIPTION

IO::Interface adds methods to IO::Socket objects that allows them to be used to retrieve and change information about the network interfaces on your system. In addition to the object-oriented access methods, you can use a function-oriented style.

THIS API IS DEPRECATED. Please see IO::Interface::Simple for the preferred way to get and set interface configuration information.

Creating a Socket to Access Interface Information

You must create a socket before you can access interface information. The socket does not have to be connected to a remote site, or even used for communication. The simplest procedure is to create a UDP protocol socket:

my $s = IO::Socket::INET->new(Proto => 'udp');

The various IO::Interface functions will now be available as methods on this socket.

Methods

@iflist = $s->if_list

The if_list() method will return a list of active interface names, for example "eth0" or "tu0". If no interfaces are configured and running, returns an empty list.

$addr = $s->if_addr($ifname [,$newaddr])

if_addr() gets or sets the interface address. Call with the interface name to retrieve the address (in dotted decimal format). Call with a new address to set the interface. In the latter case, the routine will return a true value if the operation was successful.

my $oldaddr = $s->if_addr('eth0');
$s->if_addr('eth0','192.168.8.10') || die "couldn't set address: $!";

Special case: the address of the pseudo-device "any" will return the IP address "0.0.0.0", which corresponds to the INADDR_ANY constant.

$broadcast = $s->if_broadcast($ifname [,$newbroadcast]

Get or set the interface broadcast address. If the interface does not have a broadcast address, returns undef.

$mask = $s->if_netmask($ifname [,$newmask])

Get or set the interface netmask.

$dstaddr = $s->if_dstaddr($ifname [,$newdest])

Get or set the destination address for point-to-point interfaces.

$hwaddr = $s->if_hwaddr($ifname [,$newhwaddr])

Get or set the hardware address for the interface. Currently only ethernet addresses in the form "00:60:2D:2D:51:70" are accepted.

$flags = $s->if_flags($ifname [,$newflags])

Get or set the flags for the interface. The flags are a bitmask formed from a series of constants. See "Exportable constants" below.

$ifname = $s->addr_to_interface($ifaddr)

Given an interface address in dotted form, returns the name of the interface associated with it. Special case: the INADDR_ANY address, 0.0.0.0 will return a pseudo-interface name of "any".

EXPORT

IO::Interface exports nothing by default. However, you can import the following symbol groups into your namespace:

:functions   Function-oriented interface (see below)
:flags       Flag constants (see below)
:all         All of the above

Function-Oriented Interface

By importing the ":functions" set, you can access IO::Interface in a function-oriented manner. This imports all the methods described above into your namespace. Example:

use IO::Socket;
use IO::Interface ':functions';

my $sock = IO::Socket::INET->new(Proto=>'udp');
my @interfaces = if_list($sock);
print "address = ",if_addr($sock,$interfaces[0]);

Exportable constants

The ":flags" constant imports the following constants for use with the flags returned by if_flags():

IFF_ALLMULTI
IFF_AUTOMEDIA
IFF_BROADCAST
IFF_DEBUG
IFF_LOOPBACK
IFF_MASTER
IFF_MULTICAST
IFF_NOARP
IFF_NOTRAILERS
IFF_POINTOPOINT
IFF_PORTSEL
IFF_PROMISC
IFF_RUNNING
IFF_SLAVE
IFF_UP

This example determines whether interface 'tu0' supports multicasting:

use IO::Socket;
use IO::Interface ':flags';
my $sock = IO::Socket::INET->new(Proto=>'udp');
print "can multicast!\n" if $sock->if_flags & IFF_MULTICAST.

AUTHOR

Lincoln Stein <lstein@cshl.org>

This module is distributed under the same license as Perl itself.

SEE ALSO

perl(1), IO::Socket(3), IO::Multicast(3), IO::Interface::Simple