#!/usr/bin/perl

#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 F
+oundation, either 
#version 3 of the license, or any later version.

#This program is distibuted in the hope that it will be useful, but WI
+THOUT 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 alo
+ng with this program.
#If not, see <http://www.gnu.org/licenses/>

#To contact the author of this software, send an e-mail to Bill Farley
+ (bill.farley@gmail.com).

#This script is designed to recognize and identify duplicate network b
+locks and/or overlapping
#subnets from a tab delimited file.  It requires that your tab delimit
+ed file be in the following format:
#example
#1.1.1.1    255.255.0.0
#2.2.2.2    255.255.255.0
#
#When finished, save your tab-delimited file to the same directory as 
+this script

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#

system(clear);        #clear user's terminal screen

print "Starting Script........\n\n";    #notify user that script has s
+tarted

$start = localtime;    #timestamp of when script started
$found = 0;    #counter to pass information back to the user after scr
+ipt is complete.

#open tab-delimited file and create an array for each line
open(FILE, "<$filename") || die ("Error 103 - Could not open $filename
+\n");
    $line_counter = 0; #counts the number of lines in the file
    while (<FILE>) {
        chomp $_;
        #split the line into array variables for Network and Subnetmas
+k
        ($network[$line_counter],$subnetmask[$line_counter]) = split(/
+\t/,$_);
        $line_counter++;
    }

close(FILE);

&duplicates;    #check the network array for duplicate network blocks
print "\n";    #prints a blank line between duplicates and overlaps wh
+en displayed back to user

#decriment subnetmask by one bit
$snc = 0;
foreach $network(@network) {
    $original_network = $network;    #new variable will be used as a r
+eference if any overlapping networks are found
    &slashnot;    #calls subroutine to convert decimal notation for su
+bnetmask to slash notation
    $snc++;
}
#provide user with status of script
if($found gt 0) {
    print "\nScript Complete........  Please review the previous warni
+ng(s) listed above.\n\n";
    }
else {
    print "\nScript Complete........  No duplicates or overlaps were f
+ound.\n\n";
}

$stop = localtime;

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#

sub BEGIN {

system(clear);    #clears the user's terminal

print "Subnetoverlap.pl Copyright (C) 2005, 2007 Bill Farley\n\n";
print "This program is free software: you can redistribute it and/or m
+odify it under the terms\n";
print "of the GNU General Public License as published by the Free Soft
+ware Foundation, either\n";
print "version 3 of the license, or any later version.\n";
print "This program comes with ABSOLUTELY NO WARRANTY.\n\n\n";

print "What is the filename of the tab-delimited file? (Example: file.
+txt): "; $filename = <STDIN>;

#open user provided file and remove all extra hidden characters then r
+ewrite to a new file so script will execute properly
$tempfilename = ("$filename" . "temp.txt");
open(TEXT,"<$filename") || die ("Error 101 - Can't open $filename");  
+      #user's file
open(NEW, ">$tempfilename") || die ("Error 102 - Can't open $tempfilen
+ame");        #new file that script will use
$text_counter = 0;
while (<TEXT>) {
        chomp $_;
        $_ =~ s/\r\n//g;    #checking for extra hidden characters in u
+ser's file and variables
        $_ =~s/\r//g;        #checking for extra hidden characters in 
+user's file and variables
        $_ =~s/\n//g;        #checking for extra hidden characters in 
+user's file and variables
        (($network[$text_counter], ($subnetmask[$text_counter])) = spl
+it /\t/,$_);    #separating line into two arrays
        chomp $network[$text_counter]; chomp $subnetmask[$text_counter
+];    #removing any newline characters that may be in variables
        $text_counter++;
}
                                                                      
+                                                                     
+                  
close(TEXT);
#write array variables to new file
$text_counter2 = 0;
until ($text_counter2 eq $text_counter) {
        print NEW "$network[$text_counter2]\t$subnetmask[$text_counter
+2]\n";    #writing variables into new file in tab-delimited format
        $text_counter2++;
}
                                                                      
+                                                                     
+                  
close(NEW);

#create a hash that corrolates decimal notation to slash notation
        %slash = ("128.0.0.0", 1,"192.0.0.0", 2,"224.0.0.0", 3,"240.0.
+0.0", 4,"248.0.0.0", 5,"252.0.0.0", 6,"254.0.0.0", 7,"255.0.0.0", 8,"
+255.128.0.0", 9,"255.192.0.0", 10,"255.224.0.0", 11,"255.240.0.0", 12
+,"255.248.0.0", 13,"255.252.0.0", 14,"255.254.0.0", 15,"255.255.0.0",
+ 16,"255.255.128.0", 17,"255.255.192.0", 18,"255.255.224.0", 19,"255.
+255.240.0", 20,"255.255.248.0", 21,"255.255.252.0", 22,"255.255.254.0
+", 23,"255.255.255.0", 24,"255.255.255.128", 25,"255.255.255.192", 26
+,"255.255.255.224", 27,"255.255.255.240", 28,"255.255.255.248", 29,"2
+55.255.255.252", 30,"255.255.255.254", 31,"255.255.255.255", 32,); 

#create a hash that corrolates slash notation to decimal notation
    %decimal = (1, "128.0.0.0",2, "192.0.0.0",3, "224.0.0.0",4, "240.0
+.0.0",5, "248.0.0.0",6, "252.0.0.0",7, "254.0.0.0",8, "255.0.0.0",9, 
+"255.128.0.0",10, "255.192.0.0",11, "255.224.0.0",12, "255.240.0.0",1
+3, "255.248.0.0",14, "255.252.0.0",15, "255.254.0.0",16, "255.255.0.0
+",17, "255.255.128.0",18, "255.255.192.0",19, "255.255.224.0",20, "25
+5.255.240.0",21, "255.255.248.0",22, "255.255.252.0",23, "255.255.254
+.0",24, "255.255.255.0",25, "255.255.255.128",26, "255.255.255.192",2
+7, "255.255.255.224",28, "255.255.255.240",29, "255.255.255.248",30, 
+"255.255.255.252",31, "255.255.255.254",32, "255.255.255.255",);
}

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
sub duplicates {
    $avc = 0;       #This is a counter for the array variables
    foreach $network(@network) {
            while ($avc < $line_counter) {
                    if ($network eq $network[$avc]) {       #matching 
+each array variable against all other variables in the array.
                            $match++;       #counter to keep track of 
+the variable matches since the matching variable is from
                                    #from the array, there will always
+ be at least one match against itself.
                                    #Looking for anything higher than 
+a single match to identify a true duplication
                            if ($match gt 1) {
                                    print "WARNING!!  There is a dupli
+cate network match for $network.\n";
                    $found++;
                            }
                    }
            $avc++;
            }
     $avc = 0;
    $match = 0;
    }
}

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
sub slashnot {
    foreach $key (keys(%slash)) {
        if  ($key eq $subnetmask[$snc]) {
                $new_slash = ($slash{$subnetmask[$snc]} - 1);    #decr
+imenting subnetmask of original subnetmask by one bit
            &decimalnot;    #calling subroutine to change new slash no
+tation back to decimal notation
        }
    }
}

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
sub decimalnot {
    foreach $key (keys(%decimal)) {
        if ($key eq $new_slash) {
            $new_subnetmask = $decimal{$key};    #converting slash not
+ation to decimal notation
            &binaryand;    #calling subroutine to identify new network
+ block address
        }
    }
}

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
sub binaryand {
       ($ipoctet1,$ipoctet2,$ipoctet3,$ipoctet4) = split(/\./,$network
+);       #split up the network block and assign octet variables
       ($snmoctet1,$snmoctet2,$snmoctet3,$snmoctet4) = split(/\./,$new
+_subnetmask);  #split up the subnetmask and assign octet variables
                                                                      
+                                                                     
+                  
        #Due to a bug in Perl, after the split, the new variables need
+ to have an mathmatical operation
        #performed in order to make them numeric variables rather than
+ string variables.
        $num_con1 = $snmoctet1 + $ipoctet1;
        $num_con2 = $snmoctet2 + $ipoctet2;
        $num_con3 = $snmoctet3 + $ipoctet3;
        $num_con4 = $snmoctet4 + $ipoctet4;
                                                                      
+                                                                     
+                  
        #identify the network block address by "AND"ing the ip address
+ and the subnet mask.
        $nwoctet1 = $snmoctet1 & $ipoctet1;
        $nwoctet2 = $snmoctet2 & $ipoctet2;
        $nwoctet3 = $snmoctet3 & $ipoctet3;
        $nwoctet4 = $snmoctet4 & $ipoctet4;

        $new_network = ("$nwoctet1.$nwoctet2.$nwoctet3.$nwoctet4");   
+ #joining octets together into a single variable
        $new_subnetmask = ("$snmoctet1.$snmoctet2.$snmoctet3.$snmoctet
+4");    #joining octets together into a single variable
    &overlap;    #calling subroutine to identfy any overlappping netwo
+rks
}

#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
sub overlap {
    $overlap_counter = 0;
    while($overlap_counter < $line_counter) {
        #match new subnet against all other variables in the array
        if (($new_network eq $network[$overlap_counter]) and ($new_sub
+netmask eq $subnetmask[$overlap_counter])) {
            print "WARNING!!  There is an overlap between $new_network
+ and $original_network\n";
            $found++;
        }
    $overlap_counter++;
        }
    #continue to decriment subnetmask by one bit until subnetmask is a
+ /1
    if ($new_slash ne 1) {
        $new_slash--;    #decrimenting subnetmask slash notation by on
+e bit
        &decimalnot;    #looping to subroutine for conversion back to 
+decimal notation
    }
}