check ARP table for duplicate entries. final project

spoofdetector.py

import os
import platform
from datetime import datetime


def filterARP():
    arptable_file = "data/table.txt"
    lines = []
    MACaddrs = []
    ip2mac = {}

    os.system(f"arp -a > {arptable_file}")
    with open(arptable_file, "r") as file:
        for line in file:
            l = line.strip()
            ip = ""
            macaddr = ""

            if platform.system() == "Windows":
                if l[:1] != "I" and l[:1] != "":
                    lines.append(l[:43])
                    ip = l[:21].strip()
                    macaddr = l[22:43].strip()
            else:   # linux/mac arp table
                arr = l.split(" ")
                ip = arr[1].replace("(", "").replace(")", "")
                macaddr = arr[3]
                  
            if macaddr != "" and macaddr[:5] != "ff-ff":
                ip2mac[ip] = macaddr
                MACaddrs.append(macaddr)
    
    # return MACaddrs
    return ip2mac


def dupeCheck(maclist):
    addrs = []
    dupefound = False
    maclist = list(maclist.values())

    for a in maclist:
        if a not in addrs:
            addrs.append(a)
        else:
            dupefound = True
            save2Log(a)

    if dupefound:
        print("You got dupes. Check log.")
    else:
        print("ARP table looks good.")


def save2Log(address):
    now = datetime.now()    #.strftime("%Y-%m-%d %H:%M:%S")
    with open("data/spoofed.log", "a") as logfile:
        logfile.write(f"ARP Spoofed!\nThe address is:{address}\nDate: {now}\n")


def main():
    arp_addrs = filterARP()
    # check filtered ARP
    for k in arp_addrs.keys():
        print(f"{k}\t\t-> {arp_addrs[k]}")
    dupeCheck(arp_addrs)

if __name__ == '__main__':
    main()