hosts file updater for pihole

gistfile1.txt

#!/usr/bin/env python3.6

'''
Pihole is great, but the admin interface only displays device details 
by IP address which can be confusing. This script changes the display
from IP address to a more recognizable hostname. And as a bonus, attaches
the profile (from fingerbank.org) of the device to the hostname as well - 
so instead of something like 192.168.1.101, you see galaxys6-samsung. 
Shweet. 
Usage notes
- sudo python3.6 discovery.py
- Tested with python 3.6 only
- Requires fingerbank API key (https://api.fingerbank.org/users/register) in a secrets.py file.
- Displays log messages at appropriate times
License: MIT.
'''

import os
from scapy.all import *
from python_hosts import Hosts, HostsEntry
from shutil import copyfile
import sys
import urllib3
import requests
import json
import secrets


'''
Global stuff
'''

 
interface = "wlan0"
fingerbank_url = 'https://api.fingerbank.org/api/v2/combinations/interrogate'
headers = {
    'Content-Type': 'application/json',
}

params = (
    ('key', secrets.API_KEY),
)

'''
Log message for troubleshooting
'''

def log_fingerbank_error(e, response):
    print(f' HTTP error: {e}')
    responses = {
        404: "No device was found the the specified combination",
        502: "No API backend was able to process the request.",
        429: "The amount of requests per minute has been exceeded.",
        403: "This request is forbidden. Your account may have been blocked.",
        401: "This request is unauthorized. Either your key is invalid or wasn't specified."
    }
    print(responses.get(response.status_code, "Fingerbank API returned some unknown error"))
    return

def log_packet_info(packet):
    #print(packet.summary())
    #print(ls(packet))
    print('---')
    types = {
        1: "New DHCP Discover",
        2: "New DHCP Offer",
        3: "New DHCP Request",
        5: "New DHCP Ack",
        8: "New DHCP Inform"
    }
    if DHCP in packet:
        print(types.get(packet[DHCP].options[0][1], "Some Other DHCP Packet"))
    return

def log_fingerbank_response(json_response):
    #print(json.dumps(json_response, indent=4))
    print(f"Device Profile: {json_response['device']['name']}, Confidence score: {json_response['score']}")

# https://jcutrer.com/howto/dev/python/python-scapy-dhcp-packets
def get_option(dhcp_options, key):
    must_decode = ['hostname', 'domain', 'vendor_class_id']
    try:
        for i in dhcp_options:
            if i[0] == key:
                # If DHCP Server Returned multiple name servers 
                # return all as comma seperated string.
                if key == 'name_server' and len(i) > 2:
                    return ",".join(i[1:])
                # domain and hostname are binary strings,
                # decode to unicode string before returning
                elif key in must_decode:
                    return i[1].decode()
                else: 
                    return i[1]        
    except:
        pass

def handle_dhcp_packet(packet):
    log_packet_info(packet)
    if DHCP in packet:
        requested_addr = get_option(packet[DHCP].options, 'requested_addr')
        hostname = get_option(packet[DHCP].options, 'hostname')
        param_req_list = get_option(packet[DHCP].options, 'param_req_list')
        vendor_class_id = get_option(packet[DHCP].options, 'vendor_class_id')
        print(f"Host {hostname} ({packet[Ether].src}) requested {requested_addr}.")
        device_profile = profile_device(param_req_list, packet[Ether].src, vendor_class_id)
        if ((device_profile != -1) and requested_addr):
            update_hosts_file(requested_addr, hostname, device_profile)
    return

def profile_device(dhcp_fingerprint, macaddr, vendor_class_id):
    data = {}
    data['dhcp_fingerprint'] = ','.join(map(str, dhcp_fingerprint))
    data['debug'] = 'on'
    data['mac'] = macaddr
    data['vendor_class_id'] = vendor_class_id
    print(f"Will attempt to profile using {dhcp_fingerprint}, {macaddr}, and {vendor_class_id}")

    urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

    try:
        response = requests.post(fingerbank_url, 
        headers=headers, 
        params=params, 
        data=json.dumps(data))
    except requests.exceptions.HTTPError as e:
        log_fingerbank_error(e, response)
        return -1
 
    log_fingerbank_response(response.json())

     # If score is less than 30, there is very little confidence on the returned profile. Ignore it.
    if (response.json()['score'] < 30):
        return -1
    
    return response.json()['device']['name']

'''
Update the hosts file with <hostname>-<profile> for hostname
'''

def update_hosts_file(address,hostname,profile):
    if profile is not None:
        copyfile("/etc/hosts", "hosts")
        etchostname = profile.replace(" ", "_") + ("-" + hostname if hostname else "")
        print(f"Updating hostname as: {etchostname} with {address}")

        hosts = Hosts(path='hosts')
        hosts.remove_all_matching(name=etchostname)
        new_entry = HostsEntry(entry_type='ipv4', address=address, names=[etchostname])
        hosts.add([new_entry])
        hosts.write()
        copyfile("hosts", "/etc/hosts")

        print(f"Updated Host name for hostsfile is {etchostname}")

            
print("Starting\n")
sniff(iface = interface, filter='udp and (port 67 or 68)', prn = handle_dhcp_packet, store = 0)
print("\n Shutting down...")

'''
End of file
'''

To help others out wanting to use this script, the code from @eresgit works for me if you change every 3.6.0 to 3.6.9, and it doesn't need discovery.py to be inside the scapy folder for me

Also, if you're pretty new to linux like me, to get it to run automatically you make a file like devicename.sh (I put it in the home folder) with the following in it:

#!/bin/bash
sudo python3.6 /home/pi/discovery.py

then use

chmod u+x devicename.sh
sudo crontab -e

and at the bottom of that file write @reboot /home/pi/devicename.sh