This Raspberry Pi script pings a specific host and if it's up it turns the LED on

ping-led.py

#!/usr/bin/env python3
#
# This script pings a site specified in the command line and
# turns the LED on if the site is on. It should be run as root because
# it uses sockets in the ping implementation below.
#
# Code for ping below is borrowed from https://gist.github.com/pyos/10980172
#
import time
import random
import struct
import select
import socket
import sys
from gpiozero import LED
from time import sleep

LED_PIN = 17

def chk(data):
    x = sum(x << 8 if i % 2 else x for i, x in enumerate(data)) & 0xFFFFFFFF
    x = (x >> 16) + (x & 0xFFFF)
    x = (x >> 16) + (x & 0xFFFF)
    return struct.pack('<H', ~x & 0xFFFF)


def ping(addr, timeout=1, number=1, data=b''):
    with socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP) as conn:
        payload = struct.pack('!HH', random.randrange(0, 65536), number) + data

        conn.connect((addr, 80))
        conn.sendall(b'\x08\0' + chk(b'\x08\0\0\0' + payload) + payload)
        start = time.time()

        while select.select([conn], [], [], max(0, start + timeout - time.time()))[0]:
            data = conn.recv(65536)
            if len(data) < 20 or len(data) < struct.unpack_from('!xxH', data)[0]:
                continue
            if data[20:] == b'\0\0' + chk(b'\0\0\0\0' + payload) + payload:
                return time.time() - start


if __name__ == '__main__':

    if (len(sys.argv) < 2):
        print ("Usage: " + sys.argv[0] + " <address>")
        exit(1)
        
    led = LED(LED_PIN)
    while True:
        if (bool(ping(sys.argv[1]))):
            led.on()
        else:
            led.off()
        sleep(1)