Python - Internet Control Message Protocol

• 22nd Sep, 2021
• 17:12 PM

In this lab, you will gain a better understanding of Internet Control Message Protocol (ICMP). You will learn to implement a Ping application using ICMP request and reply messages.

from socket import *
import os
import sys
import struct
import time
import select
import binascii

ICMP_ECHO_REQUEST = 8

packageSent = 0
packageReceive = 0

def checksum(string):
    csum = 0
    countTo = (len(string) // 2) * 2
    count = 0

    while count < countTo>         thisVal = (string[count + 1]) * 256 + (string[count])
        csum += thisVal
        csum &= 0xffffffff
        count += 2

    if countTo < len>         csum += (string[len(string) - 1])
        csum &= 0xffffffff

    csum = (csum >> 16) + (csum & 0xffff)
    csum = csum + (csum >> 16)
    answer = ~csum
    answer = answer & 0xffff
    answer = answer >> 8 | (answer << 8>     return answer

def receiveOnePing(mySocket, ID, timeout, destAddr):
    global packageReceive
    timeLeft = timeout

    while 1:
        startedSelect = time.time()
        whatReady = select.select([mySocket], [], [], timeLeft)
        howLongInSelect = (time.time() - startedSelect)
        if whatReady[0] == []:  # Timeout
            return "Request timed out."

        timeReceived = time.time()
        recPacket, addr = mySocket.recvfrom(1024)

        # Fill in start
        # Fetch the ICMP header from the IP packet
        header = recPacket[20:28]
        type, code, checksum, packageID, sequence = struct.unpack("bbHHh", header)
        if packageID == ID:
            time_offset = struct.calcsize("d")
            timeSent = struct.unpack("d", recPacket[28:28 + time_offset])[0]
            packageReceive += 1
            return timeReceived - timeSent
        # Fill in end
        timeLeft = timeLeft - howLongInSelect
        if timeLeft <= 0:
            return "Request timed out."

def sendOnePing(mySocket, destAddr, ID):
    # Header is type (8), code (8), checksum (16), id (16), sequence (16)
    global packageSent

    myChecksum = 0
    # Make a dummy header with a 0 checksum
    # struct -- Interpret strings as packed binary data
    header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, myChecksum, ID, 1)
    data = struct.pack("d", time.time())
    # Calculate the checksum on the data and the dummy header.
    myChecksum = checksum(header + data)

    # Get the right checksum, and put in the header

    if sys.platform == 'darwin':
        # Convert 16-bit integers from host to network  byte order
        myChecksum = htons(myChecksum) & 0xffff
    else:
        myChecksum = htons(myChecksum)

    header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, myChecksum, ID, 1)
    packet = header + data

    mySocket.sendto(packet, (destAddr, 1))  # AF_INET address must be tuple, not str

    packageSent += 1
    # Both LISTS and TUPLES consist of a number of objects
    # which can be referenced by their position number within the object.

def doOnePing(destAddr, timeout):
    icmp = getprotobyname("icmp")

    # SOCK_RAW is a powerful socket type. For more details:   http://sockraw.org/papers/sock_raw
    mySocket = socket(AF_INET, SOCK_RAW, icmp)

    myID = os.getpid() & 0xFFFF  # Return the current process i
    sendOnePing(mySocket, destAddr, myID)
    delay = receiveOnePing(mySocket, myID, timeout, destAddr)
    mySocket.close()
    return delay

def average(arrays):
    avg_sum = 0
    for i in arrays:
        avg_sum += i
    return (avg_sum / len(arrays))

def ping(host, timeout=1):
    # timeout=1 means: If one second goes by without a reply from the server,      # the client assumes that either the client's ping or the server's pong is lost
    dest = gethostbyname(host)
    print("Pinging " + dest + " aka " + host + " using Python:")
    print("")
    delays = []
    # Send ping requests to a server separated by approximately one second
    count = 5
    while count:
        delay = doOnePing(dest, timeout)
        print("Ping times " + str(count) + " RTT = " + str(delay))
        time.sleep(1)  # one second
        count -= 1
        delays.append(delay)
    print("")
    print("The maximum RTT is: " + str(max(delays)))
    print("The minimum RTT is: " + str(min(delays)))
    print("The average RTT is " + str(sum(delays)/len(delays)))
    print("The package loss rate is " + str(1 - packageReceive/packageSent))
    return delays

host = input("Enter address want to ping: ")
ping(host)
#ping("google.com")