#!/usr/bin/perl
#######################################
# Author: Tomas Jensen / TDC          #
# Email.: tcj@tdc.dk                  #
#######################################
#
### Pragma's
use strict;
use warnings;
use Socket;
use Net::SNMP qw(:snmp);

my $IfNumbers = '1.3.6.1.2.1.2.1.0';
my $IfListStart ='1.3.6.1.2.1.2.2.1.';
my %IfProp = ("Description"=>2,
			  "Type"=>3,
			  "MTU"=>4,
			  "Speed"=>5,
			  "MAC"=>6,
			  "AdminStatus"=>7,
			  "InOctets"=>10,
			  "OutOctets"=>16,
			  "InErrors"=>14,
			  "OutErrors"=>20
			  );
my $intnr;
my %interfaces;
my $interface;
my $key;
my $value;
my $ip;
my $addr;
my @result;
my $i;

#################### SUBS ######################

sub RealIp {
	## Find real ip address
	my $pip = shift;
	
	if ( $pip =~ /^[1-9][0-9]*\.[0-9]+\.[0-9]+\.[0-9]+$/ ){
		# Vi har en aegte ip
		return $pip;
	} else {
		if ( $pip =~ /^0.*/ ) {
			# Fjern indledende 0'er
			$pip =~ s/^0+//;
			return $pip;
		} else {
			# lav get host by name
			$addr = inet_aton("$pip");
			$addr = inet_ntoa ($addr);
			if ( defined $addr ){
				return $addr;
			}
		}
	}
}

sub GetIntNrs {
	## Find og returner antal interfaces
	# Input  : session
	# OutPut : antal If
	
	my $session = shift;
	my $OID;
	my $ifn;

	my $result = $session->get_request(
					-varbindlist => [$IfNumbers]);
	
	if ( ! defined $result) {
		print "Arrrrr - Kiks i GetIntNrs!!!\n";
	}
	
	($OID, $ifn) = each %{$result};
	
	return $ifn;
}

sub GetIntInfo {
	## Hent et interface
	# Input  : session
	# Input  : OID
	# Output : Tekstinfo
	
	my $session = shift;
	my $OID = shift;
	my $info;
	my $result = $session->get_request(
					-varbindlist => [$OID]);
	
	if ( ! defined $result) {
		print "Arrrrr - Kiks i GetIntInfo!!!\n";
	}
	
	($OID, $info) = each %{$result};
	return $info;
	
}
##################### MAIN ######################

print "Indtast ip eller host: ";
my $host = <>;
chomp $host;

$ip = RealIp($host);

## Sæt session op
my ($session, $error) = Net::SNMP->session(
			 -hostname => $ip,
             -version  => '2c', );
 
	if (!defined($session)) {
		printf("Kan ikke åbne session til $host fejl: $error\n");
	}

## Hent interface antal
print "Henter antal interfaces: \n";
printf " - Der er %s interfaces.\n", ($intnr = GetIntNrs $session);

print "Følgende findes:\n";
for ($i = 1; $i <= $intnr; $i++) {
	printf "%s - %s\n", $i, (GetIntInfo $session, "$IfListStart"."$IfProp{'Description'}".".$i");
}

## Hvilket interface skal vises
print "Hvilket interface skal vises. Vælg mellem 1 og $intnr: ";
$interface = <>;
chomp $interface;

if ( $interface >= $intnr ) {
	print "Dette interface findes ikke...\n";
	exit;
}

## Præsenter interfacet
foreach $key ( keys %IfProp ){
	printf "%12s --> %s\n", $key, (GetIntInfo $session, "$IfListStart"."$IfProp{$key}".".$interface");
}