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#!/usr/local/bin/perl -w
require 5.002;
use strict;
use SNMP_Session "0.59";
use BER;
use Socket;
use Getopt::Long;
sub usage ();
my $snmp_version = '2';
GetOptions ("version=i" => \$snmp_version);
my $bgp4PathAttrASPathSegment = [1,3,6,1,2,1,15,6,1,5];
my $hostname = $ARGV[0] || usage ();
my $community = $ARGV[1] || "public";
my $session;
die "Couldn't open SNMP session to $hostname"
unless ($session =
($snmp_version eq '1' ? SNMP_Session->open ($hostname, $community, 161)
: SNMPv2c_Session->open ($hostname, $community, 161)));
$session->map_table ([$bgp4PathAttrASPathSegment],
sub () {
my ($index, $as_path_segment) = @_;
my ($dest_net, $preflen, $peer)
= ($index =~ /([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)\.([0-9]+)\.([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)/);
grep (defined $_ && ($_=pretty_print $_),
($as_path_segment));
printf "%-18s %-15s %s\n",
$dest_net."/".$preflen, $peer, pretty_as_path ($as_path_segment);
});
$session->close ();
1;
sub pretty_addr ($ ) {
my ($addr) = @_;
my ($hostname,$aliases,$addrtype,$length,@addrs)
= gethostbyaddr (inet_aton ($addr), AF_INET);
$hostname ? $hostname." [".$addr."]" : $addr;
}
sub hostname ($ ) {
my ($addr) = @_;
my ($hostname,$aliases,$addrtype,$length,@addrs)
= gethostbyaddr (inet_aton ($addr), AF_INET);
$hostname || "[".$addr."]";
}
sub pretty_as_path ($ ) {
my ($aps) = @_;
my $start = 0;
my $result = '';
while (length ($aps) > $start) {
my ($type,$length) = unpack ("CC", substr ($aps, $start, 2));
$start += 2;
my ($pretty_ases, $next_start) = pretty_ases ($length, $aps, $start);
$result .= ($type == 1 ? "SET " : $type == 2 ? "" : "type $type??")
.$pretty_ases;
$start = $next_start;
}
$result;
}
sub pretty_ases ($$$ ) {
my ($length, $aps, $start) = @_;
my $result = undef;
return ('',0) if $length == 0;
while ($length-- > 0) {
my $as = unpack ("S", substr ($aps, $start, 2));
$start += 2;
$result = defined $result ? $result." ".$as : $as;
}
($result, $start);
}
sub usage () {
die "usage: $0 host [community]";
}
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