#!/usr/bin/perl -wT
#
# mcastsum - summarize router multicast state using Net::SNMP
#            2005-02-20, dwcarder: misc hacks to prettify output
#            2005-10-18-a,jtk: limited public release
#            2005-10-18-b,jtk: added msdpEnabled check
#            2005-10-20-a,jtk: comments/doc
#
# This script simply pulls some simple state information out of a
# multicast enabled router and summarizes the results.  It was written
# quickly and not without a lot of sanity checks though it should not
# cause any harm other than a few failed SNMP queries if it doesn't
# work for you.  This script was mainly written as a quick exmaple
# in hopes that it might be useful as a quick view into multicast
# router resource conditions or to encourage a better tool or set of
# tools to do similar things.
#
# You'll need Net::SNMP.  Run as follows:
#
#   ./mcastsum -r <router name or IP address> -c <community string>
#
# TODO: more summary info
#       better error/sanity checking
#       more descriptive output

use strict;
$|=1;

use Getopt::Long;
use Net::SNMP qw(oid_lex_sort);

## for troubleshooting, e.g. print Dumper($var)
#use Data::Dumper;
##

# global vars
my $options = 0;     # GetOptions return code
my $community = "";  # SNMP community string
my $router = "";     # router hostname or IP address
my $result;          # generic SNMP status handler
my $interface;       # interface id place holder
my @if_indexes = (); # interface id list
my %mcast = ();      # multicast state hash

# oid variables
my $sysName = ".1.3.6.1.2.1.1.5.0";
my $ifIndex = ".1.3.6.1.2.1.2.2.1.1";
my $ifName = ".1.3.6.1.2.1.31.1.1.1.1";
my $igmpInterfaceJoins = ".1.3.6.1.3.59.1.1.1.1.11";
my $igmpInterfaceLeaves = ".1.3.6.1.3.59.1.1.1.1.12";
my $igmpInterfaceGroups = ".1.3.6.1.3.59.1.1.1.1.13";
my $ipMRouteInIfIndex = ".1.3.6.1.3.60.1.1.2.1.5";
my $ipMRouteInterfaceInMcastOctets = ".1.3.6.1.3.60.1.1.4.1.5";
my $ipMRouteInterfaceOutMcastOctets = ".1.3.6.1.3.60.1.1.4.1.6";
my $msdpNumSACacheEntries = ".1.3.6.1.3.92.1.1.3.0";
my $msdpEnabled = ".1.3.6.1.3.92.1.1.1.0";

$options = GetOptions( "c=s" => \$community,
                       "r=s" => \$router );

if(!$community || !$router) { usage(); }   # check for community and router

# setup SNMP session
#
my ($session, $error) = Net::SNMP->session( -hostname=>$router,
                                           -community=>$community);

if(!defined($session)) {
    dienice(__LINE__, "SNMP session creation error: " . $error);
}

# sysName
$result = $session->get_request($sysName);
if(defined($result)) {
    print "# sysName: ", $result->{$sysName}, "\n";
} else {
    print "# sysName: [ unknown ]\n";
}

# ifIndex
print "# Getting router interface list...\n";
$result = $session->get_table(-baseoid => $ifIndex);

# TODO: what is a better way to check for error?
if(!defined($result)) {
    dienice(__LINE__, "SNMP get error: " . $error);
}

# build ifIndex array
foreach my $oid (oid_lex_sort(keys(%{$result}))) {
     push(@if_indexes,$result->{$oid});
}

# Here is the hash hashes structure we're building:
#
# %mcast = {
#     ifIndex => {
#           'ifName' => name,
#           'igmpInterfaceJoins' => joins,
#           'igmpInterfaceLeaves' => leaves,
#           'igmpInterfaceGroups => groups,
#           'ipMRouteInterfaceInMcastOctets => octets,
#           'ipMRouteInterfaceOutMcastOctets => octets
#     }
#     ...
# }
#
# TODO

# get ifName
print "# Getting interface names...\n";
foreach $interface (@if_indexes) {
    $result = $session->get_request("$ifName.$interface");
    # TODO: do an error check
    $mcast{$interface}{'ifName'} = $result->{"$ifName.$interface"};
}

# note: PIM uses a null interface, manually add it to %mcast
$mcast{'0'}{'ifName'} = "null";
$mcast{'0'}{'igmpInterfaceJoins'} = -1;
$mcast{'0'}{'igmpInterfaceLeaves'} = -1;
$mcast{'0'}{'igmpInterfaceGroups'} = -1;
$mcast{'0'}{'ipMRouteInterfaceInMcastOctets'} = -1;
$mcast{'0'}{'ipMRouteInterfaceOutMcastOctets'} = -1;

# get igmpInterfaceJoins
print "# Getting interface IGMP joins...\n";
foreach $interface (@if_indexes) {
    $result = $session->get_request("$igmpInterfaceJoins.$interface");
    # note, some are likely to come back as undef
    if(!defined($result)) {
        # undefined interfaces receive value = -1
        $mcast{$interface}{'igmpInterfaceJoins'} = -1;
    } else {
        # TODO: do an error check
        $mcast{$interface}{'igmpInterfaceJoins'} =
            $result->{"$igmpInterfaceJoins.$interface"};
    }
}

# get igmpInterfaceGroups
print "# Getting interface IGMP group membership...\n";
foreach $interface (@if_indexes) {
    $result = $session->get_request("$igmpInterfaceGroups.$interface");
    # note, some are likely to come back as undef
    if(!defined($result)) {
        # undefined interfaces receive value = -1
        $mcast{$interface}{'igmpInterfaceGroups'} = -1;
    } else {
        # TODO: do an error check
        $mcast{$interface}{'igmpInterfaceGroups'} =
            $result->{"$igmpInterfaceGroups.$interface"};
    }
}
 
# get igmpInterfaceLeaves
print "# Getting interface IGMP leaves...\n";
foreach $interface (@if_indexes) {
    $result = $session->get_request("$igmpInterfaceLeaves.$interface");
    # note, some are likely to come back as undef
    if(!defined($result)) {
        # undefined interfaces receive value = -1
        $mcast{$interface}{'igmpInterfaceLeaves'} = -1;
    } else {
        # TODO: do an error check
        $mcast{$interface}{'igmpInterfaceLeaves'} =
            $result->{"$igmpInterfaceLeaves.$interface"};
    }
}

# get ipMRouteInIfIndex
print "# Getting mroute list...\n";
$result = $session->get_table(-baseoid => $ipMRouteInIfIndex);

# TODO: what is a better way to check for error?
if(!defined($result)) {
    dienice(__LINE__, "SNMP get error: " . $error);
}

# calculate interface ipMRouteInIfIndex totals
foreach my $oid (oid_lex_sort(keys(%{$result}))) {
     $mcast{$result->{$oid}}{'ipMRouteInIfIndex'}++;
}

# get ipMRouteInterfaceInMcastOctets
print "# Getting ipMRouteInterfaceInMcastOctets...\n";
foreach $interface (@if_indexes) {
    $result =
        $session->get_request("$ipMRouteInterfaceInMcastOctets.$interface");
    # note, some are likely to come back as undef
    if(!defined($result)) {
        # undefined interfaces receive value = -1
        $mcast{$interface}{'ipMRouteInterfaceInMcastOctets'} = -1;
    } else {
        # TODO: do an error check
        $mcast{$interface}{'ipMRouteInterfaceInMcastOctets'} =
            $result->{"$ipMRouteInterfaceInMcastOctets.$interface"};
    }
}
# get ipMRouteInterfaceOutMcastOctets
print "# Getting ipMRouteInterfaceOutMcastOctets...\n";
foreach $interface (@if_indexes) {
    $result =
        $session->get_request("$ipMRouteInterfaceOutMcastOctets.$interface");
    # note, some are likely to come back as undef
    if(!defined($result)) {
        # undefined interfaces receive value = -1
        $mcast{$interface}{'ipMRouteInterfaceOutMcastOctets'} = -1;
    } else {
        # TODO: do an error check
        $mcast{$interface}{'ipMRouteInterfaceOutMcastOctets'} =
            $result->{"$ipMRouteInterfaceOutMcastOctets.$interface"};
    }
}
 

print "  Int      joins   leaves   groups   routes     inoctets    outoctets\n";
foreach my $key (sort {numonly($mcast{$a}{'ifName'}) <=> numonly($mcast{$b}{'ifName'})} keys %mcast) {

    my $joins = 0;
    my $leaves = 0;
    my $groups = 0;
    my $routes = 0;
    my $inoctets = 0;
    my $outoctets = 0;

    if($mcast{$key}{'igmpInterfaceJoins'} > 0) {
        $joins = $mcast{$key}{'igmpInterfaceJoins'};
    }
    
    if($mcast{$key}{'igmpInterfaceLeaves'} > 0) {
        $leaves = $mcast{$key}{'igmpInterfaceLeaves'};
    }

    if($mcast{$key}{'igmpInterfaceGroups'} > 0) {
        $groups = $mcast{$key}{'igmpInterfaceGroups'};
    }

    if(defined($mcast{$key}{'ipMRouteInIfIndex'})) {
        $routes = $mcast{$key}{'ipMRouteInIfIndex'};
    }

    if($mcast{$key}{'ipMRouteInterfaceInMcastOctets'} > 0) {
        $inoctets = $mcast{$key}{'ipMRouteInterfaceInMcastOctets'};
    }

    if($mcast{$key}{'ipMRouteInterfaceOutMcastOctets'} > 0) {
        $outoctets = $mcast{$key}{'ipMRouteInterfaceOutMcastOctets'};
    }

    if ($joins||$leaves||$groups||$routes||$inoctets||$outoctets) {
        printf("%7s %8d %8d %8d %8d %12u %12u \n", $mcast{$key}{'ifName'},$joins,$leaves,$groups,$routes,$inoctets,$outoctets);
    }

}

# get msdpNumSACAcheEntries
$result = $session->get_request($msdpEnabled);
# TODO: do an error check
if($result->{"$msdpEnabled"} == 1) {
    print "# Getting MSDP SA cache...\n";
    $result = $session->get_request($msdpNumSACacheEntries);
    # TODO: do an error check
    print "  MSDP SA count: ", $result->{"$msdpNumSACacheEntries"}, "\n";
} else {
    print "# MSDP disabled, skipping...\n";
}

# TODO: get most popular groups across interfaces
# TODO: get most popular IGMP/PIM/MSDP group
# TODO: get most popular PIM/MSDP source
# TODO: calculate SA diff between MSDP routers - maybe different script

$result=$session->close;
if($result) {
    dienice(__LINE__, "SNMP session close error: " . $error);
}

### subroutines

# incorrect command line parameters
sub usage {
    print STDERR "Usage: $0 -c community_string -r router\n";
    exit(1);
}

## dienice() - something bad happened, exit gracefully
##
sub dienice {

#TODO: validate passed vars

    my $linenum = shift;
    my $message = shift;

    print STDERR "WARNING(", $linenum, "): ", $message, "\n";
    print STDERR "Operation aborted.\n";
    exit 1;
}


sub numonly {
  my $val = shift;
  $val =~ m/(\d+)/;
  my $ret = $1;
  if (!defined($ret)) { $ret = '0'; }
  return ($ret);
}