Search for duplicated MAC (hardware address)

• Intro
• Script

Intro

Script

#!/import/bin/python3

# look for duplicate MAC in -p path 
# hopefully client's config is not in one line, 
# otherwise the script may show 'funny' results
# --------------------------------------------

import os
import socket
import sys
import fileinput
import re
import subprocess
import smtplib
from email.mime.text import MIMEText
import argparse

parser = argparse.ArgumentParser(
                           description="Search for duplicated MAC in DHCP reservation",
                           epilog='Brought to you by Zarko')
parser.add_argument("-p", "--path", help="Path of clients' configs, example /etc/dhcp/clients", required=True)
args = parser.parse_args()
CLNTDIR=args.path

# tmp files
ALLMAC = "/tmp/allmac"
UNIQMAC = "/tmp/uniqmac"
DPLMAC = "/tmp/dplmac"
MSGTXT = "/tmp/body"

if not os.path.exists(CLNTDIR):
    sys.exit("ERROR: " + CLNTDIR + " does not exist.")

def remove_tmp_files():
    """
    Remove tmep files
    """
    if os.path.exists(ALLMAC):
        os.remove(ALLMAC)
    if os.path.exists(UNIQMAC):
        os.remove(UNIQMAC)
    if os.path.exists(DPLMAC):
        os.remove(DPLMAC)
    if os.path.exists(MSGTXT):
        os.remove(MSGTXT)

def send_email():
    """
    Send email with info about duplicates
    """
    with open(MSGTXT, "r") as fm:
        message = MIMEText(
        fm.read()
        ) 
    message['Subject'] = "WARNING, %s duplicated MAC in " % duplicate_number + socket.gethostname()
    fromaddr = 'labops-support@dom.com'
    toaddr = 'zarko@dom.com'

    try:
        email_object = smtplib.SMTP(host="mail-router.dom.com")
        email_object.sendmail(fromaddr, toaddr, message.as_string())
    except:
        sys.exit("Error: can't send email")


def find_duplicates():
    """
    Find duplicated and its number
    """
    global duplicate_number
    global duplicate_mac
    macregex = re.compile('([0-9a-fA-F]{1,2}[:]){5}([0-9a-fA-F]{1,2})')

    try:
        for root, dirs, files in os.walk(CLNTDIR):
            for clientname in files:
                try:
                    with open(CLNTDIR + "/" + clientname, "r") as f:
                        allmac = open(ALLMAC, "a+")
                        for line in f:
                            if macregex.search(line): 
                                allmac.write(line.lower().strip().replace("hardware ethernet", "").replace(";", "") + "\n")
                        allmac.close() 
                except IOError as err:
                    sys.exit("IOError: {0}".format(err))
    except Exception as err:   # general exception
        sys.exit("Error: {0}".format(err))

    subprocess.check_output(["cat %s | sed 's/[ ]*$//g' |sort -f | uniq -i| tee %s " % (ALLMAC, UNIQMAC)], shell=True) # sed removes any space
    subprocess.check_output(["cat %s | sed 's/[ ]*$//g' |sort -f | uniq -id | tee %s" % (ALLMAC, DPLMAC)], shell=True)
    duplicate_mac = subprocess.check_output(["cat %s" % DPLMAC], shell=True).decode('ASCII').strip()
    duplicate_number = subprocess.check_output(["cat %s | wc -l" % DPLMAC], shell=True).decode('ASCII').strip()


if __name__ == '__main__':

    remove_tmp_files()

    find_duplicates()

    if int(duplicate_number) > 0:

        for mac in duplicate_mac.split():
            with open(MSGTXT, "a+") as msg:
                msg.write("\n" + mac + " is owned by:\n")
                pattern = re.compile(mac, re.IGNORECASE)
                try:
                    for root, dirs, files in os.walk(CLNTDIR):
                        for clientname in files:
                            with open(CLNTDIR + "/" + clientname, "r") as f:
                                for line in f:
                                    if pattern.search(line):
                                        msg.write(clientname + "\n")
                except Exception as err:   # general exception
                    sys.exit("Error: {0}".format(err))

        send_email()

    remove_tmp_files()

sys.exit(0)

Subject: WARNING, 1 duplicated MAC in dhcp-server.dom.com

00:11:e0:c3:b7:fc is owned by:
install-test-1.dom.com
x7-2.dom.com