#!/usr/bin/perl -w
#
# Return a list of hosts which not reachable via ICMP echo
#
# Jim Trocki, trockij@transmeta.com
#
# This module is modified to recognize hosts in format
# username[:password]@host/database ...
# which is used my pgsql.monitor (of course, just host is used) by
# Dobrica Pavlinusic, dpavlin@rot13.org
# http://www.rot13.org/~dpavlin/sysadm.html
#
# $Id: fping.monitor 1.7 Mon, 27 Aug 2001 14:22:45 -0400 trockij $
#
#    Copyright (C) 1998, Jim Trocki
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
use strict;

use Getopt::Std;

my %opt;
getopts ("ahr:s:t:T", \%opt);

sub usage
{
    print <<EOF;
usage: fping.monitor [-a] [-r num] [-s num] [-t num] [-T] host [host...]

    -a		only report failure if all hosts are unreachable
    -r num	retry "num" times for each host before reporting failure
    -s num	consider hosts which respond in over "num" msecs failures
    -t num	wait "num" msecs before sending retries
    -T		traceroute to each failed host. CAUTION: this may cause
    		this monitor to hang for a very long time

EOF

    exit;
}

usage if ($opt{"h"});

my $TIMEOUT = $opt{"t"} || 2000;
my $RETRIES = $opt{"r"} || 3;
my $CMD = "fping -e -r $RETRIES -t $TIMEOUT";
my $START_TIME = time;
my $END_TIME;

exit 0 if (@ARGV == 0);

my @hosts;

# you can use hosts in format host:optional configuration parameters and
# this part will strip everything after hostname
foreach (@ARGV) {
	if (m/^[^:]+:?[^\@]*\@([^\/]+)\/?.*/) {
		my $host = $1;
		push @hosts,$host if (! grep /^$host$/,@hosts);
	} else {
		push @hosts,$_ if (! grep /^$_$/,@hosts);
	}
}

open (IN, "$CMD @hosts 2>&1 |") ||
	die "could not open pipe to fping: $!\n";

my @unreachable;
my @alive;
my @slow;
my @other_prob;		# details for other per-host problems
my @error;		# other errors which I'll give non-zero exit for
my @icmp;		# ICMP messages output by fping
my %addr_unknown;

my %want_host = map { $_ => 1 } @hosts;	# hosts fping hasn't output yet

while (<IN>)
{
    chomp;
    if (/^(\S+).*unreachable/)
    {
    	push (@unreachable, $1);
    	delete $want_host{$1}
	    or push @error, "unreachable host `$1' wasn't asked for";
    }

    elsif (/^(\S+) is alive \((\S+)/)
    {
    	delete $want_host{$1}
	    or push @error, "reachable host `$1' wasn't asked for";

	if ($opt{"s"} && $2 > $opt{"s"})
	{
	    push (@slow, [$1, $2]);
	}

	else
	{
	    push (@alive, [$1, $2]);
	}
    }

    elsif (/^(\S+)\s+address\s+not\s+found/)
    {
    	$addr_unknown{$1} = 1;
    	push @other_prob, "$1 address not found";
	push @unreachable, $1;
    	delete $want_host{$1}
	    or push @error, "unknown host `$1' wasn't asked for";
    }

    # ICMP Host Unreachable from 1.2.3.4 for ICMP Echo sent to 2.4.6.8
    # (among others)

    elsif (/^ICMP (.*) for ICMP Echo sent to (\S+)/)
    {
    	push @icmp, $_;
    }

    else
    {
    	push @error, "unidentified output from fping: [$_]";
    }
}

for my $host (keys %want_host) {
    push @other_prob, "$host not listed in fping's output";
    push @unreachable, $host;
}

close (IN);

$END_TIME = time;

my $retval = $? >> 8;

if ($retval < 3)
{
    # do nothing
}

elsif ($retval == 3)
{
    push @error, "fping: invalid cmdline arguments [$CMD @ARGV]";
}

elsif ($retval == 4)
{
    push @error, "fping: system call failure";
}

else
{
    push @error, "unknown return code ($retval) from fping";
}

if (@error) {
    print "unusual errors\n";
}
else {
    my @fail = sort @unreachable, map { $_->[0] } @slow;
    # This line is intentionally blank if there are no failures.
    print "@fail\n";
}

print "\n";
print "start time: " . localtime ($START_TIME) . "\n";
print "end time  : " . localtime ($END_TIME) . "\n";
print "duration  : " . ($END_TIME - $START_TIME) . " seconds\n";

if (@error != 0)
{
    print <<EOF;

------------------------------------------------------------------------------
unusual errors
------------------------------------------------------------------------------
EOF
    print join ("\n", @error), "\n";
}

if (@unreachable != 0)
{
    print <<EOF;

------------------------------------------------------------------------------
unreachable hosts
------------------------------------------------------------------------------
EOF
    print join ("\n", @unreachable), "\n";

    print "\nother problems:\n", join "\n", @other_prob, ''
	if @other_prob;
}

if (@icmp != 0)
{
    print <<EOF;

------------------------------------------------------------------------------
ICMP messages
------------------------------------------------------------------------------
EOF
    print join "\n", @icmp, '';
}


if (@slow != 0)
{
    print <<EOF;

------------------------------------------------------------------------------
slow hosts (response time which exceeds $opt{s}ms)
------------------------------------------------------------------------------
EOF

    foreach my $host (@slow)
    {
    	printf ("%-40s %.2f ms\n", @{$host});
    }
}



if (@alive != 0)
{
    print <<EOF;

------------------------------------------------------------------------------
reachable hosts                          rtt
------------------------------------------------------------------------------
EOF
    
    for (my $i = 0; $i < @alive; $i++)
    {
    	printf ("%-40s %.2f ms\n", @{$alive[$i]});
    }
}

#
# traceroute
#
if ($opt{"T"} && @unreachable)
{
    my $header_output = 0;
    foreach my $host (@unreachable)
    {
    	next if $addr_unknown{$host};
    	print $header_output++ ? "\n" : <<EOF;

------------------------------------------------------------------------------
traceroute to unreachable hosts
------------------------------------------------------------------------------
EOF
    	system ("traceroute -w 3 $host 2>&1");
    }
}

exit 1 if @error;

#
# fail only if all hosts do not respond
#
if ($opt{"a"})
{
    exit(@alive ? 0 : 1);
}

exit 1 if (@slow != 0);

exit $retval;