#!/usr/bin/env perl

use 5.010;
use warnings;
use strict;

use Net::Ping;
use Getopt::Std;
use IO::Socket;

my $proto;              # ping protocol
my $host;               # remote host
my $bind_addr;          # local ip interface to bind
my $bind_port;          # local port to bind
my $monitoring_node;          # monitoring status node
my $monitoring_name;          # cantain formatted remote host name to insert into a monitoring node
my %options=();         # hash to work with options
my $result;             # ping probe result
my $latency;            # latency to remote host
my $sock;               # network sockect object
my $agent_socket;       # network sockect object
my $interval;           # delay between checks

$|=1;

# Getting options

getopts("p:h::n:i:s:d:", \%options);

sub CheckArgs() {

# Checking for non-mandatory options

        if (defined ($options{p})) { $proto = $options{p}; } else { $proto = "tcp"; };
        if (defined ($options{i})) { $bind_addr = $options{i}; } else { $bind_addr="0.0.0.0"; };
        if (defined ($options{s})) { $bind_port = $options{s}; } else { $bind_port = "9906"; };
        if (defined ($options{d})) { $interval = $options{d}; } else { $interval = "5"; };

# Checking for mandatory options

        if (defined ($options{h}) && defined ($options{n})) {
                $host = $options{h};
                $monitoring_node = $options{n};
                &Main;
        } else {
                &PrintHelp;
                exit 1;
        }
}

sub PrintHelp() {

        print "Latency monitor v1.5.1\nOptions:\n   -p  Ping protocol to use: tcp(default), udp, icmp(requires root)\n   -h  Destination host. IP or DNS name can be specified. Mandatory option, no have default value\n   -n  status node to report. Mandatory option, no default value\n   -d  Delay between checks in seconds. Default value 5\n   -i  IP interface to bind. Default value 0.0.0.0\n   -s  Socket to bind. Default value 9906\n";
        exit;
}

sub Main() {

# New network socket instance

        $sock = new IO::Socket::INET (
                LocalHost => "$bind_addr",
                LocalPort => "$bind_port",
                Proto => 'tcp',
                Listen => 5,
                Type => SOCK_STREAM,
                Reuse => 1
        ) or die "Can't create socket: $!\n";

# New ping instance

        my $ping = Net::Ping->new("$proto")
        or die "Can't initialize ping: $!\n";

        $monitoring_name = $host;
        $monitoring_name =~ s/\./-/;
        $agent_socket = $sock->accept();

# Main loop

        while (42) {
                ($result,$latency) = $ping->ping($host);
                $latency *= 1000;
                $latency =~ s/\.\d+//;

                print $agent_socket $monitoring_node . ".lmonitor." . $monitoring_name . ".rtt.value=" . $latency . "\n";
                sleep $interval;
        }

        $sock->close;

}

&CheckArgs;