#!/usr/local/bin/perl
# 
# $Header: dns_response.pl 28-apr-2005.14:21:40 afontana Exp $
#
# dns_response.pl
# 
# Copyright (c) 2004, 2005, Oracle. All rights reserved.  
#
#    NAME
#      dns_response.pl - <one-line expansion of the name>
#
#    DESCRIPTION
#      <short description of component this file declares/defines>
#
#    NOTES
#      <other useful comments, qualifications, etc.>
#
#    MODIFIED   (MM/DD/YY)
#    afontana    04/28/05 - do not report response time when validation fails 
#    afontana    04/05/05 - clean up error messages 
#    afontana    02/14/05 - dont sleep after last try 
#    afontana    12/30/04 - adjust columns 
#    afontana    12/27/04 - change tries to retries 
#    afontana    11/12/04 - change seconds to millis 
#    afontana    11/02/04 - add em_result= 
#    afontana    11/01/04 - afontana_dns_metric
#    afontana    10/27/04 - move timing 
#    afontana    10/26/04 - Creation
# 

use Getopt::Long; # set up to accept user input

##
## Note that this requires a special modified version of Net::DNS
## in order to get timing data accurately.
##
use Net::DNS;

#require "semd_common.pl";
my %cmdLine = ();
# Parse the input parameters and put them in the cmdLine hash table
GetOptions(\%cmdLine,
           "beaconName=s",
           "txnName=s",
           "address=s",
           "querytype=s",
           "nameserver=s",
	   "nameserverport=i",
	   "protocol=s",
	   "timeout=i",
	   "numretries=i",
           "retryinterval=i",
	   "srcport=i",
	   "srcaddr=s",
	   "validation=s");

my $beaconName = $cmdLine{"beaconName"};
my $txnName = $cmdLine{"txnName"};
my $address = $cmdLine{"address"};
my $querytype = $cmdLine{"querytype"};

my $nameserver = $cmdLine{"nameserver"};
my $nameserverport = $cmdLine{"nameserverport"} ;
my $protocol = $cmdLine{"protocol"};
my $timeout = $cmdLine{"timeout"};
my $numretries = $cmdLine{"numretries"};
my $retryinterval = $cmdLine{"retryinterval"};
my $srcport = $cmdLine{"srcport"};
my $srcaddr = $cmdLine{"srcaddr"};
my $validation = $cmdLine{"validation"};

#default
$nameserverport = 53 unless (exists $cmdLine{"nameserverport"});
$timeout = 5 unless (exists $cmdLine{"timeout"});
$numretries = 1 unless (exists  $cmdLine{"numretries"});
$retryinterval = 5 unless (exists  $cmdLine{"retryinterval"});
$srcport = 0 unless(exists  $cmdLine{"srcport"});

#
# Set up the DNS resolver.
#
my $res = Net::DNS::Resolver->new(debug=>0,
                                  igntc=>1,
				  recurse=>1,
				  retrans=>0,
				  retry=>1);

$res->port($nameserverport);
if ("" ne $nameserver)
{
  $res->nameservers("$nameserver");
}

if ($protocol eq "tcp")
{
  $res->usevc(1);
  $res->tcp_timeout($timeout);
} else {
  $res->usevc(0);
  $res->udp_timeout($timeout);
}

$res->srcport($srcport);
if ("" ne $srcaddr)
{
  $res->srcaddr($srcaddr);
}


##
## Perform the actual query
##
my $query = Net::DNS::Packet->new($address, $querytype);
my $response;
my $actualtries = 0;
while ($numretries >= $actualtries)
{
  $actualtries += 1;
  $response = $res->send($query);
  if ( ($response && $response->header->ancount > 0) ||
       ($numretries < $actualtries))
  {
    last;
  }
  else
  {
    sleep($retryinterval);
  }
}



##
## Validate The Response
##
#if ($response && $response->header->ancount > 0)
if ($response)
{
  my @result = ();
  my $missing;
  my @validate_array = split (/[ ,]+/, $validation);
  my %result_set = ();
  my $ttl = 0x7fffffff;


##
## Iterate through each row, skipping answers that are not the desired type.
##

  if ($response->header->ancount > 0) {
  foreach my $rr ($response->answer) {
    my $rr_addr;

    if ($rr->type eq $querytype && $querytype eq "A"){
      $rr_addr = $rr->address;
    } elsif ($rr->type eq $querytype && $querytype eq "MX") {
      $rr_addr = $rr->exchange;
    } elsif ($rr->type eq $querytype && $querytype eq "CNAME") {
      $rr_addr = $rr->cname;
    }

    if ($rr_addr) {
      $result_set->{$rr_addr} = 1;
      push(@result, $rr_addr);
      $ttl = $rr->ttl unless ($ttl < $rr->ttl);
    }
  }
  }

  foreach my $expected (@validate_array) {
    $missing .= ($expected . " ") unless ($result_set->{$expected} == 1);
  }

  if ($missing || $response->header->ancount < 1) {
    my $errString;
    if ($response->header->ancount < 1)
    {
      $errString = "No results";
      $ttl = "";
    }
    else
    {
      $errString = ("Missing entries: " . $missing);
    }


    ##
    ## Validation failure
    ##
    print "em_result=";

    #Transaction Name
    print $txnName . "|";
    #Beacon Name
    print $beaconName . "|";
    #Status
    print "0|";
    #Total Time
    print "|";
    #Connect Time
    print "|";
    #TTL
    print "|";
    #Num Retries
    print (($actualtries - 1) . "|");
    #Num Results
    print ((scalar keys %$result_set) . "|");
    #Result
    print $errString;

  } else {

    ##
    ## Success case
    ##  
    print "em_result=";


    #Transaction Name
    print $txnName . "|";
    #Beacon Name
    print $beaconName . "|";
    #Status
    print "1|";
    #Total Time
    print (($res->total_time * 1000) . "|");
    #Connect Time
    if ($res->usevc == 1) {
      print (($res->connect_time * 1000) . "|");
    } else {
      print "|";
    }
    #TTL
    print ($ttl . "|");
    #Num Retries
    print (($actualtries - 1) . "|");
    #Num Results
    print ((scalar keys %$result_set) . "|");
    #Result
    print join(", ", @result);
  }
}
else
{
  ##
  ## DNS Failure
  ##
  print "em_result=";

  #Transaction Name
  print $txnName . "|";
  #Beacon Name
  print $beaconName . "|";
  #Status
  print "0|";
  #Total Time
  print "|";
  #Connect Time
  print "|";
  #TTL
  print "|";
  #Num Retries
  print (($actualtries - 1) . "|");
  #Num Results
  print "|";
  #Result
  print "No DNS Response";
  #Error string may be useful, but is sometimes unintelligible
  #print $res->errorstring;
}