str_ = bytearray(str_)

csum = 0

countTo = (len(str_) // 2) * 2

for count in range(0, countTo, 2):

thisVal = str_[count+1] * 256 + str_[count]

csum = csum + thisVal

csum = csum & 0xffffffff

if countTo < len(str_):

csum = csum + str_[-1]

csum = csum & 0xffffffff

csum = (csum >> 16) + (csum & 0xffff)

csum = csum + (csum >> 16)

answer = ~csum

answer = answer & 0xffff

answer = answer >> 8 | (answer << 8 & 0xff00)

startTime = time.time()

while (startTime + timeout - time.time()) > 0:

try:

recPacket, (addr, x) = mySocket.recvfrom(1024)

except socket.timeout:

break # timed out

timeReceived = time.time()

# Fetch the ICMPHeader fromt the IP

icmpHeader = recPacket[20:28]

icmpType, code, checksum, packetID, sequence = struct.unpack(

"bbHHh", icmpHeader)

if icmpType == 11 and code == 0:

return (timeReceived - startTime, addr, None)

elif icmpType == 0 and code == 0:

return (timeReceived - startTime, addr, DESTINATION_REACHED)

# Make a dummy header with a 0 checksum

# Header is type (8), code (8), checksum (16), id (16), sequence (16)

header = struct.pack("bbHHh",

ICMP_ECHO_REQUEST, # type (byte)

0, # code (byte)

0, # checksum (halfword, 2 bytes)

ID, # ID (halfword)

1) # sequence (halfword)

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':

# htons: Convert 16-bit integers from host to network byte order

myChecksum = socket.htons(myChecksum) & 0xffff

else:

myChecksum = socket.htons(myChecksum)

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

packet = header + data

# AF_INET address must be tuple, not str

icmp = socket.getprotobyname("icmp")

# SOCK_RAW is a powerful socket type. For more details:

# http://sock-raw.org/papers/sock_raw

mySocket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)

mySocket.setsockopt(socket.SOL_IP, socket.IP_TTL, ttl)

mySocket.settimeout(timeout)

myID = os.getpid() & 0xFFFF # Return the current process i

sendOnePing(mySocket, destAddr, myID)

delay = receiveOnePing(mySocket, myID, timeout, destAddr)

mySocket.close()

if not delay:

print('*', end=' ', flush=True)

return

delay *= 1000

if not prevaddr == address:

try:

host, _, _ = socket.gethostbyaddr(address)

except:

host = address

print('{} ({}) {:.3f} ms'.format(host, address, delay),

end=' ', flush=True)

else:

print(' {:.3f} ms'.format(delay),

# 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 = socket.gethostbyname(host)

print("traceroute to %s (%s), %d hops max" % (host, dest, maxHops))

# Send ping requests to a server separated by approximately one second

for ttl in range(1, maxHops+1):

print('{:2} '.format(ttl), end=' ')

prevaddr = None

for i in range(3):

delay, address, info = doOnePing(dest, timeout, ttl)

print_part(delay, address, prevaddr)

prevaddr = address

print()

if info == DESTINATION_REACHED: