#!/usr/bin/perl -w
# Note: Some lines have been wrapped for readability
# names of the input log file / output hostnames file
#
$log_in_file = "log.txt";
$html_results_file = "hostnames_out.htm";
# run parts of the program
&get_hostnames;
&html;
&save_html_page;
# template for displaying hostnames
sub html {
$html_page = <<__READ_HTML__;
Hostnames
__READ_HTML__
} ### end sub html
sub get_hostnames {
# read in the raw log file to @data
open( DAT, $log_in_file ) || die("Error log file must be \"$log_in_file\"");
@data = ;
close(DAT);
# initialise a variable to strip new line characters from a string
use vars qw/$NLT/;
$NLT = qr/(?:\r|\n|\t)/;
# prevent un-initialised errors
$all_ip = '';
$all_hn_ip = '';
$all_sp_ip = '';
$hn_ip = '';
$sp_hn_ip = '';
$sp_lines = '';
# if a line number was entered on the command line e.g. perl ip_resolver.pl 1724
# start resolving IPs from this point on
if ( $ARGV[0] ) { $in_line_from = $ARGV[0]; }
else { $in_line_from = 0; }
foreach $line (@data) {
$line_no++;
if ( $line_no >= $in_line_from ) {
if ($line) {
$line =~ s/$NLT//g;
($ip) = split( /\ /, $line );
# if IP is a number in the format ***.***.***.*** then
if ( $ip =~ m!(\d+)\.(\d+)\.(\d+)\.(\d+)! ) {
# if the IP has allready been resolved then skip this part
unless ( $all_ip =~ /$ip/ ) {
$all_ip = $all_ip . "$ip ";
$hostname = '';
# resolve the actual IP address
$hostname =
( gethostbyaddr( pack( 'C4', $1, $2, $3, $4 ), 2 ) )
[0];
$hostname = $hostname || 'no reverse DNS';
# get the length of the hostname to line up the columns
$ocharno = length($hostname);
if ( $ocharno > 50 ) { $charno = 1; }
else { $charno = 50 - $ocharno; }
# add this amount of space characters to make up the
# rest of the line untill the start of the IP address
$addspace = " " x $charno;
print $hostname . $addspace . $ip . "\n";
# use various colours for the various hostnames
$line_start = '';
$line_end = '';
if ( $hostname =~ /edu/i ) {
$line_start = '';
}
if ( $hostname =~ /(com|net|org)/i ) {
$line_start = '';
}
if ( $hostname =~ /(gov|mil)/i ) {
$line_start = '';
}
# compile the finished hostname / IP line complete with
# font colour
$hn_ip =
$line_start
. $hostname
. $addspace
. $ip
. $line_end . "\n";
#add this line to the rest
$all_hn_ip = $all_hn_ip . $hn_ip;
# if the hostname is a special one (gov/mil) then add
# it to a special store of its own to be displaye d at
# the top of the page and also add the coresponding raw
# log lines to a special store
if ( $hostname =~ /(gov|mil)/i ) {
$sp_hn_ip = $sp_hn_ip . $hn_ip;
$addunderline = "-" x $ocharno;
$sp_lines =
$sp_lines . "\n$hostname\n$addunderline\n";
$all_sp_ip = $all_sp_ip . "$ip ";
}
}
# if we have a special IP then store the log lines for it
if ( $all_sp_ip =~ /$ip/ ) {
$sp_lines = $sp_lines . " " . $line . "\n";
}
}
}
}
}
# if there are special hostnames present then sort out the line spacing
if ($sp_hn_ip) {
$all_hn_ip =
$all_hn_ip . "\n"
. "============================*.GOV / *.MIL============================\n\n"
. $sp_hn_ip
. $sp_lines;
}
}
sub save_html_page {
# save the finished html page to a file ready for viewing
open( DAT, ">$html_results_file" )
|| die(
"Error ensure this script has write permissions \"$html_results_file\""
);
print DAT "$html_page";
close(DAT);
}