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IO::Interface.3pm

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 = $if\n";
     print "addr =      ",$if->address,"\n",
           "broadcast = ",$if->broadcast,"\n",
           "netmask =   ",$if->netmask,"\n",
           "dstaddr =   ",$if->dstaddr,"\n",
           "hwaddr =    ",$if->hwaddr,"\n",
           "mtu =       ",$if->mtu,"\n",
           "metric =    ",$if->metric,"\n",
           "index =     ",$if->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