IcmpPing.py

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

ICMP_ECHO_REQUEST = 8
NUM_PACKETS = 3


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

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

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

    csum = (csum >> 16) + (csum & 0xffff)
    csum = csum + (csum >> 16)
    answer = ~csum
    answer = answer & 0xffff
    answer = answer >> 8 | (answer << 8 & 0xff00)
    return answer


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

    while True:
        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)

        # Fetch the ICMPHeader from the received IP
        #Fill in start
        icmp_header = recPacket[20:28]
        #Fill in end

        rawTTL = struct.unpack("s", bytes([recPacket[8]]))[0]

        # binascii -- Convert between binary and ASCII
        TTL = int(binascii.hexlify(rawTTL), 16)

        # Fetch icmpType, code, checksum, packetID, and sequence from ICMPHeader using struct.unpack method
        # Fill in start
        icmpType, code, checksum, packetID, sequence = struct.unpack(
            "bbHHh", icmp_header)
        # Fill in end

        if packetID == ID:
            byte = struct.calcsize("d")
            timeSent = struct.unpack("d", recPacket[28:28 + byte])[0]
            return "Reply from %s: bytes=%d time=%f5ms TTL=%d" % (destAddr, len(recPacket), (timeReceived - timeSent) * 1000, TTL)

        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)

    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

    # AF_INET address must be tuple, not string
    mySocket.sendto(packet, (destAddr, 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://sock-raw.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 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 + " using Python:")
    print("")
    # Send ping requests to a server separated by approximately one second
    for i in range(NUM_PACKETS):
        delay = doOnePing(dest, timeout)
        print(delay)
        time.sleep(1)  # one second
    return delay


if __name__ == '__main__':
    host = sys.argv[1]
    ping(host)
    # ping("google.com")
    # ping("www.suzunoya.com")
    # ping("localhost")