Net::SNMP::Mixin::Dot1qFdb - mixin class for 802.1-Q switch forwarding databases

  use Net::SNMP;
  use Net::SNMP::Mixin qw/mixer init_mixins/;

  my $session = Net::SNMP->session( -hostname => 'foo.bar.com' );
  $session->mixer('Net::SNMP::Mixin::Dot1qFdb');
  $session->init_mixins();
  snmp_dispatcher()   if $session->nonblocking;
  die $session->error if $session->error;

  foreach my $fdb_entry ( $session->get_dot1q_fdb_entries() ) {
    my $mac     = $fdb_entry->{MacAddress};
    my $fdb_id  = $fdb_entry->{fdbId};
    my $vlan_id = $fdb_entry->{vlanId};
    my $port    = $fdb_entry->{dot1dBasePort};
    my $status  = $fdb_entry->{fdbStatus};

    print "$mac, $fdb_id, $vlan_id, $port, $status\n";
  }

    {
      MacAddress      => 'XX:XX:XX:XX:XX:XX',
      dot1dBasePort   => Integer,
      fdbId           => Integer,
      vlanId          => Integer,
      fdbStatus       => Integer,
      fdbStatusString => String,
    }

  RT: http://rt.cpan.org/Public/Dist/Display.html?Name=Net-SNMP-Mixin-Dot1qFdb

package Net::SNMP::Mixin::Dot1qFdb;

use strict;
use warnings;

#
# store this package name in a handy variable,
# used for unambiguous prefix of mixin attributes
# storage in object hash
#
my $prefix = __PACKAGE__;

#
# this module import config
#
use Carp ();
use Net::SNMP::Mixin::Util qw/idx2val normalize_mac/;

#
# this module export config
#
my @mixin_methods;

BEGIN {
  @mixin_methods = ( qw/ get_dot1q_fdb_entries /);
}

use Sub::Exporter -setup => {
  exports => [@mixin_methods],
  groups  => { default => [@mixin_methods], },
};

#
# SNMP oid constants used in this module
#
use constant {
  DOT1Q_TP_FDB_TABLE   => '1.3.6.1.2.1.17.7.1.2.2',
  DOT1Q_TP_FDB_ADDRESS => '1.3.6.1.2.1.17.7.1.2.2.1.1',
  DOT1Q_TP_FDB_PORT    => '1.3.6.1.2.1.17.7.1.2.2.1.2',
  DOT1Q_TP_FDB_STATUS  => '1.3.6.1.2.1.17.7.1.2.2.1.3',

  DOT1Q_VLAN_CURRENT_FDB_ID => '1.3.6.1.2.1.17.7.1.4.2.1.3',
};

our $VERSION = '0.04';

sub get_dot1q_fdb_entries {
  my $session = shift;
  Carp::croak "'$prefix' not initialized,"
    unless $session->{$prefix}{__initialized};

  #
  # the port's current state translation table
  #
  my %fdp_entry_status_enum = (
    1 => 'other',
    2 => 'invalid',
    3 => 'learned',
    4 => 'self',
    5 => 'mgmt',
  );

  # stash for return values
  my @fdb_entries = ();

  my ( @digits, $fdb_id, $vlan_id, $mac, $mac_string, $port, $status,
    $status_string );

  # index is fdbId.MacAddress
  foreach my $idx ( keys %{ $session->{$prefix}{dot1qTpFdbPort} } ) {
    $port   = $session->{$prefix}{dot1qTpFdbPort}{$idx};
    $status = $session->{$prefix}{dot1qTpFdbStatus}{$idx};

    # the snmp get_table() isn't a snapshot, it can be, that
    # the MAC has already timeout in the FDB when the
    # status is fetched
    next unless defined $port && defined $status;

    $status_string = $fdp_entry_status_enum{$status};

    # split the idx to fdb_id and mac address
    # index is fdbId.MacAddress, value is the bridge port
    @digits = split /\./, $idx;

    $fdb_id = $digits[0];
    $vlan_id = $session->{$prefix}{fdb_id2vlan_id}{$fdb_id};

    $mac        = pack( 'C6', @digits[ 1 .. 6 ] );
    $mac_string = normalize_mac($mac);

    push @fdb_entries,
      {
      dot1dBasePort   => $port,
      MacAddress      => $mac_string,
      fdbId           => $fdb_id,
      vlanId          => $vlan_id,
      fdbStatus       => $status,
      fdbStatusString => $status_string,
      };
  }

  return @fdb_entries;
}

sub _init {
  my ( $session, $reload ) = @_;

  die "$prefix already initalized and reload not forced.\n"
    if $session->{$prefix}{__initialized} && not $reload;

  # initialize the object for forwarding databases infos
  _fetch_dot1q_fdbid($session);
  return if $session->error;

  _fetch_dot1q_tp_fdb_entries($session);
  return if $session->error;

  return 1;
}

sub _fetch_dot1q_fdbid() {
  my $session = shift;
  my $result;

  # fetch the dot1qVlanFdbId from dot1qVlanCurrentTable
  $result = $session->get_table(
    -baseoid => DOT1Q_VLAN_CURRENT_FDB_ID,

    # define callback if in nonblocking mode
    $session->nonblocking ? ( -callback => \&_dot1q_fdbid_cb ) : (),
  );

  return unless defined $result;
  return 1 if $session->nonblocking;

  # call the callback function in blocking mode by hand
  _dot1q_fdbid_cb($session);

}

sub _dot1q_fdbid_cb {
  my $session = shift;
  my $vbl     = $session->var_bind_list;

  return unless defined $vbl;

  # mangle result table to get plain vlan_id => fdb_id
  #
  #         1.3.6.1.2.1.17.7.1.4.2.1.3.0.n => m
  #                                  | | |    |
  # DOT1Q_VLAN_CURRENT_FDB_ID -------/ | |    |
  #         dot1qVlanTimeMark ---------/ |    |
  #            dot1qVlanIndex -----------/    |
  #            dot1qVlanFdbId ----------------/

  # vlan_id => fdb_id
  $session->{$prefix}{vlan_id2fdb_id} =
    idx2val( $vbl, DOT1Q_VLAN_CURRENT_FDB_ID, 1 );

  # build reverse map fdb_id => vlan_id
  while ( my ( $vlan_id, $fdb_id ) =
    each %{ $session->{$prefix}{vlan_id2fdb_id} } )
  {

    $session->{$prefix}{fdb_id2vlan_id}{$fdb_id} = $vlan_id;
  }

  $session->{$prefix}{__initialized}++;
}

sub _fetch_dot1q_tp_fdb_entries() {
  my $session = shift;
  my $result;

  # fetch the forwarding databases from dot1qTpFdbTable
  $result = $session->get_entries(
    -columns => [ DOT1Q_TP_FDB_PORT, DOT1Q_TP_FDB_STATUS ],

    # define callback if in nonblocking mode
    $session->nonblocking
    ? ( -callback => \&_dot1q_tp_fdb_entries_cb )
    : (),
  );

  return unless defined $result;
  return 1 if $session->nonblocking;

  # call the callback function in blocking mode by hand
  _dot1q_tp_fdb_entries_cb($session);

}

sub _dot1q_tp_fdb_entries_cb {
  my $session = shift;
  my $vbl     = $session->var_bind_list;

  return unless defined $vbl;

  # mangle result table to get plain idx->value
  # index is fdbId.MacAddress, value is the bridge port
  $session->{$prefix}{dot1qTpFdbPort} = idx2val( $vbl, DOT1Q_TP_FDB_PORT );

  # mangle result table to get plain idx->value
  # index is fdbId.MacAddress, value is the entry status
  $session->{$prefix}{dot1qTpFdbStatus} = idx2val( $vbl, DOT1Q_TP_FDB_STATUS );

  $session->{$prefix}{__initialized}++;
}

unless ( caller() ) {
  print "$prefix compiles and initializes successful.\n";
}

1;

# vim: sw=2