#!/usr/bin/perl
# vi:syntax=perl
#
# Name:
#   mrrogers
#   Licensed under Don't Worry, Be Happy
#    see: http://wiki.xdroop.com/space/Software+Licensing
#
# Synopsis
#   list LLDP neighbours listed in SNMP
#
# Options
#  see &usage
#
# History:
#   2014-07-16 D.Mackintosh
#   Initial rev
#
# Usefull Values.

use Net::SNMP qw(snmp_dispatcher oid_lex_sort);

$BASENAME = $0;
$BASENAME =~ s|\\|/|g;
if ($BASENAME =~ m|(.*/)(.*)|)
{
    $BASENAME = $2;
}
#
# code here.

while ($#ARGV > -1)
{
    $_ = shift @ARGV;
    if (/^-c$/) { $COMMUNITY      = shift @ARGV; next; }
    if (/^-s$/) { $SHOWLOCALPORTS = 1;           next; }
    if (/^-p$/) { $PORTID         = 1;           next; }
    if (/^-l$/) { $SpecificPort   = shift @ARGV; next; }
    if (/^--DEBUG$/) { $DEBUG = 1; &debug("Debugging on"); next; }
    if (/^--HELP$/) { &usage("__SHOW_HELP"); }
    if (!$switch) { $switch = $_; next; }
    &usage("$_");
}

#
# display the help message.
#  I find it usefull to leave this subroutine here, next to the parameter
#  parsing, as it makes it much easer to keep the help and the
#  actual parsing in sync.
sub usage
{
    $gripe = shift @_;
    print <<"EO_USAGE";
$BASENAME [-c STRING ] [-p] TARGET
    TARGET         query the switch at ip, or named, TARGET
    -c STRING      use STRING as the SNMP community
    -l PORT        show neighbour on PORT only
    -p             display remote PortID strings as well as PortDesc strings
    -s             show local PortID
    --HELP         print this screen
EO_USAGE
    exit 0 if ($gripe eq "__SHOW_HELP");
    &die("Don't understand:$gripe");
}

$switch    = $switch    || '192.168.1.1';
$COMMUNITY = $COMMUNITY || 'public';

if ($PORTID)
{
    &loadLLDPPortID();
}

&loadLLDPPortDesc();
&loadLLDPSysName();

if ($SpecificPort)
{
    print &showNeighbour($SpecificPort) . "\n";
    exit;
}

foreach $localPort (sort(keys(%RemotePortDesc)))
{
    print &showNeighbour($localPort) . "\n";
}

#
# Return the ifName for a given ifIndex.

sub ifName
{
    my $ifIndex = shift(@_);
    my $ifName;
    my $ifNameOID     = '1.3.6.1.2.1.31.1.1.1.1';
    my $ifNameOIDPort = "$ifNameOID.$ifIndex";
    &debug("ifName: ifNameOIDPort -> $ifNameOIDPort");
    my ($nameSession, $nameError) = Net::SNMP->session(
        -hostname  => $switch,
        -community => $COMMUNITY,
        -port      => 161,
    );
    if (!defined($nameSession))
    {
        &die("ifName: no session");
    }
    $ifName = $nameSession->get_request(-varbindlist => [$ifNameOIDPort],);
    $ifName = $ifName->{$ifNameOIDPort};
    return ($ifName);
}

#
# load the LLDPPortDesc column into %RemotePortDesc

sub loadLLDPPortDesc
{
    my $LLDPPortDesc = '1.0.8802.1.1.2.1.4.1.1.8';
    my ($session, $error) = Net::SNMP->session(
        -hostname  => $switch,
        -community => $COMMUNITY,
        -port      => 161,
        -translate => [-octetstring => 0x0]    # http://rt.cpan.org/Public/Bug/Display.html?id=1946
    );
    if (!defined($session))
    {
        printf("ERROR: %s\n", $error);
        exit 1;
    }
    if (defined($result = $session->get_table(-baseoid => $LLDPPortDesc)))
    {
        foreach (oid_lex_sort(keys(%{$result})))
        {
            $raw   = $_;
            $value = $result->{$_};
            if ($raw =~ /\.(\d+)\.\d+$/)
            {
                $raw = $1;
            }
            $RemotePortDesc{$raw} = $value;
            &debug("LLDPPortDesc: [$raw] -> [$value]");
        }
    }
    else
    {
        printf("ERROR: %s\n(load-LLDPPortDesc)\n", $session->error());
    }
}

#
# Load the LLDPPortID column into %RemotePortID

sub loadLLDPPortID
{
    my $LLDPPortID = '1.0.8802.1.1.2.1.4.1.1.7';
    my ($session, $error) = Net::SNMP->session(
        -hostname  => $switch,
        -community => $COMMUNITY,
        -port      => 161,
        -translate => [-octetstring => 0x0]    # http://rt.cpan.org/Public/Bug/Display.html?id=1946
    );
    if (!defined($session))
    {
        printf("ERROR: %s\n", $error);
        exit 1;
    }
    if (defined($result = $session->get_table(-baseoid => $LLDPPortID)))
    {
        foreach (oid_lex_sort(keys(%{$result})))
        {
            $raw   = $_;
            $value = $result->{$_};
            if ($raw =~ /\.(\d+)\.\d+$/)
            {
                $raw = $1;
            }
            $RemotePortID{$raw} = $value;
            &debug("LLDPortID: [$raw] -> [$value]");
        }
    }
    else
    {
        printf("ERROR: %s\n(loadLLDPPortID)\n", $session->error());
    }
}

#
# Load the LLDPSysName column into %RemoteSysName

sub loadLLDPSysName
{
    my $LLDPSysName = '1.0.8802.1.1.2.1.4.1.1.9';
    my ($session, $error) = Net::SNMP->session(
        -hostname  => $switch,
        -community => $COMMUNITY,
        -port      => 161,
        -translate => [-octetstring => 0x0]    # http://rt.cpan.org/Public/Bug/Display.html?id=1946
    );
    if (!defined($session))
    {
        printf("ERROR: %s\n", $error);
        exit 1;
    }
    if (defined($result = $session->get_table(-baseoid => $LLDPSysName)))
    {
        foreach (oid_lex_sort(keys(%{$result})))
        {
            $raw   = $_;
            $value = $result->{$_};
            if ($raw =~ /\.(\d+)\.\d+$/)
            {
                $raw = $1;
            }
            $RemoteSysName{$raw} = $value;
            &debug("LLDPSysName: [$raw] -> [$value]");
        }
    }
    else
    {
        printf("ERROR: %s\n(loadLLDPSysName)\n", $session->error());
    }
}

#
# Return the output string for the given ifIndex

sub showNeighbour
{
    my $ifIndex = shift(@_);
    my $LocalPortName;
    my $out;
    $LocalPortName = &ifName($ifIndex);
    if ($SHOWLOCALPORTS)
    {
        $out = "($ifIndex) ";
    }
    $out = $out . "$LocalPortName -> $RemoteSysName{$ifIndex} $RemotePortDesc{$ifIndex}";
    if ($PORTID)
    {
        $out = $out . " ($RemotePortID{$ifIndex})";
    }
    return $out;
}

# These subroutines come from my Perl template and are used just for
#  my convenience.
#
# an easy way to change those back-ticks into
#  system() calls when we fuck up.

sub doThis
{
    local ($result);
    local ($thing) = pop @_;
    &debug("doing [$thing]");

    #       $result=system($thing);
    $result = `$thing`;
    &debug("finished shelling; output:\n$result");
    &debug("output ends");
    return $result;
}

#
# Log something to the local syslog

sub logItem
{
    local ($message);
    $message = pop(@_);
    setlogsock('unix');
    openlog($BASENAME, '', 'user');
    syslog('info', $message);
    closelog;
}

#
# A (braindead) friend for our undertaker.

sub warn
{
    local ($gripe);
    $gripe = pop(@_);
    print STDERR "$BASENAME:$gripe\n";
    &logItem($gripe);
}

#
# A simple debug outputer.

sub debug
{
    local ($gripe);
    $gripe = pop(@_);
    $DEBUG && print STDERR "DEBUG:$gripe\n";
}

#
# A (braindead) undertaker.

sub die
{
    local ($gripe);
    $gripe = pop(@_);
    &warn("fatal:$gripe");
    &logItem("fatal:$gripe");
    exit 1;
}