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Python error when using assign operator TOS = precedence[data >> 5] + tabs + delay[D] + tabs + throughput[T] + tabs + reliability[R] + tabs = cost[M]

Trying to get a script to work and it displays an error at the spot listed in the Title. It is stating that there is an error that says cannot assign to operator. Have looked around multiple sites and even re-watched the video to see if anything was missing. The video was in Python version two, and the installed version on the computer is version 3.7.2. So far there has been no luck determining the reason for the error, nor has anything been identified that changed between version 2 and 3 in regard to the assign operator. Any assistance in identifying the error would be greatly appreciated. The full script is as follows:
import socket
import sys
import struct
import re
def receiveData(s):
data = ''
try:
data = s.recvfrom(65565)
except timeout:
data = ''
except:
print("An error happened")
sys.exc_info()
return data[0]
# get the type of service - 8 bits
def getTOS(data):
precedence = {0: "Routine", 1: "Priority", 2: "Immediate", 3: "Flash", 4: "Flash override", 5: "Crtiical", 6: "Internetwork control", 7: "Network control"}
delay = {0: "Normal delay", 1: "Low delay"}
throughput = {0: "Normal throughput", 1: "High throughput"}
reliability = {0: "Normal reliability", 1: "High reliability"}
cost = {0: "Normal monetary cost", 1: "Minimize monetary cost"}
D = data & 0X10
D >>= 4
T = data & 0x8
T >>= 3
R = data & 0x4
R >>= 2
M = data & 0x2
M >>= 1
tabs = "\n\t\t\t"
TOS = precedence[data >> 5] + tabs + delay[D] + tabs + throughput[T] + tabs + reliability[R] + tabs = cost[M]
return TOS
def getFlags(data):
flagR = {0: "0 - Reserved bit"}
flagDF = {0: "0 - Fragment if necessary', 1: '1 - Do not fragment"}
flagMF = {0: "0 - Last fragment", 1: "1 - More fragments"}
R = data & 0X8000
R >>= 15
DF = data & 0x4000
DF >>= 14
MF = data & 0x2000
MF >>= 13
tabs = "\n\t\t\t"
flags = flagR[R] + tabs + flagDF[DF] + tabs = flagMF[MF]
return flags
def getProtocol(protocolNr):
protocolFile = open("Protocol.txt", "r")
protocolData = protocolFile.read()
protocol = re.findall(r"\n" + str(protocolNR) + " (?:.)+\n", protocolData)
if protocol:
protocol = protocol[0]
protocol = protocol.replace("\n", "")
protocol = protocol.replace(str(protocolNr), "")
protocol = protocol.lstrip()
return protocol
else:
return "No such protocol."
# the public network interface
HOST = socket.gethostbyname(socket.gethostname())
print ("host: ", HOST)
# create a raw socket and bind it to the public interface
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_IP)
# bind the socket to the network interface
s.bind((HOST,0))
# Include IP headers
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
# receive all packages
s.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)
data = receiveData(s)
unpackedData = struct.unpack('!BBHHHBBH4s4s', data[:20])
version_IHL = unpackedData[0]
version = version_IHL >> 4
IHL = version_IHL & 0xF
TOS = unpackedData[1]
totalLength = unpackedData[2]
ID = unpackedData[3]
flags = unpackedData[4]
fragmentOffset = unpackedData[4] & 0X1FFF
TTL = unpackedData[5]
protocolNr = unpackedData[6]
checksum = unpackedData[7]
sourceAddress = socket.inet_ntoa(unpackedData[8])
destinationAddress = socket.inet_ntoa(unpackedData[9])
print ("An IP packet with the size %i was captured.") % (totalLength)
print ("Raw data: ") + data
print ("\nParsed data")
print ("Version:\t\t") + str(version)
print ("Header Length:\t\t") + str(IHL*4) + "bytes"
print ("Type of Service:\t") + getTOS(TOS)
print ("Length:\t\t\t") + str(totalLength)
print ("ID:\t\t\t") + str(hex(ID)) + " (" + str(ID) + ")"
print ("Flags:\t\t\t") + getFlags(flags)
print ("Fragment offset:\t") + str(fragmentOffset)
print ("TTL:\t\t\t") + str(TTL)
print ("Protocol:\t\t") + getProtocol(protocolNr)
print ("Checksum:\t\t") + str(checksum)
print ("Source:\t\t\t") + sourceAddress
print ("Destination:\t\t") + destinationAddress
print ("Payload:\n") + data[20:]
# disabled promiscuous mode
s.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)

Increase SYN packet sending rate in the python script

I am using raw sockets in python to send SYN packets repeatedly at high rate for a project. I am able to send SYN at a rate of 120 Mb/S using below python Script. Is there a way to optimize it to increase the rate of the packets?
I think CPU is the bottleneck, as my NIC supports upto 1 Gbps. I am even constructing the packet once and just resending it repeatedly.
# some imports
import thread
import socket, sys
from struct import *
import time
import datetime as dt
def sendFunc(s, packet, dest_ip, sizeOfPacket):
start_time = time.time()
i = 0
while(1):
time_diff = time.time() - start_time
i = i + 1
if time_diff > 1:
start_time = time.time()
print i*sizeOfPacket
i = 0
s.sendto(packet, (dest_ip , 0 )) # put this in a loop if you want to flood the target
# checksum functions needed for calculation checksum
def checksum(msg):
s = 0
# loop taking 2 characters at a time
for i in range(0, len(msg), 2):
w = (ord(msg[i]) << 8) + (ord(msg[i+1]) )
s = s + w
s = (s>>16) + (s & 0xffff);
#s = s + (s >> 16);
#complement and mask to 4 byte short
s = ~s & 0xffff
return s
#create a raw socket
try:
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
except socket.error , msg:
print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
# tell kernel not to put in headers, since we are providing it
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
# now start constructing the packet
packet = '';
source_ip = 'x.x.x.x'
dest_ip = 'y.y.y.y' # or socket.gethostbyname('www.google.com')
# ip header fields
ihl = 5
version = 4
tos = 0
tot_len = 20 + 20 # python seems to correctly fill the total length, dont know how ??
id = 54321 #Id of this packet
frag_off = 0
ttl = 255
protocol = socket.IPPROTO_TCP
check = 10 # python seems to correctly fill the checksum
saddr = socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to
daddr = socket.inet_aton ( dest_ip )
ihl_version = (version << 4) + ihl
# the ! in the pack format string means network order
ip_header = pack('!BBHHHBBH4s4s' , ihl_version, tos, tot_len, id, frag_off, ttl, protocol, check, saddr, daddr)
# tcp header fields
source = 1234 # source port
dest = 80 # destination port
seq = 0
ack_seq = 0
doff = 5 #4 bit field, size of tcp header, 5 * 4 = 20 bytes
#tcp flags
fin = 0
syn = 1
rst = 0
psh = 0
ack = 0
urg = 0
window = socket.htons (5840) # maximum allowed window size
check = 0
urg_ptr = 0
offset_res = (doff << 4) + 0
tcp_flags = fin + (syn << 1) + (rst << 2) + (psh <<3) + (ack << 4) + (urg << 5)
# the ! in the pack format string means network order
tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags, window, check, urg_ptr)
# pseudo header fields
source_address = socket.inet_aton( source_ip )
dest_address = socket.inet_aton(dest_ip)
placeholder = 0
protocol = socket.IPPROTO_TCP
tcp_length = len(tcp_header)
psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length);
psh = psh + tcp_header;
tcp_checksum = checksum(psh)
# make the tcp header again and fill the correct checksum
tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags, window, tcp_checksum , urg_ptr)
# final full packet - syn packets dont have any data
packet = ip_header + tcp_header
#Send the packet finally - the port specified has no effect
print "size of packet", len(packet)
sendFunc(s, packet, dest_ip, len(packet))

Socket Error when using socket.sendto()

So, I have a problem where when I use s.sendto(). Once I arrange all the information to be put into the packet and I try to send it, it ends up telling me there is something wrong with my arguments.
The code below is the code I'm using (admittedly from this website).
# some imports
import socket, sys
from struct import *
# checksum functions needed for calculation checksum
def checksum(msg):
s = 0
# loop taking 2 characters at a time
for i in range(0, len(msg), 2):
w = (ord(msg[i]) << 8) + (ord(msg[i+1]) )
s = s + w
s = (s>>16) + (s & 0xffff);
#s = s + (s >> 16);
#complement and mask to 4 byte short
s = ~s & 0xffff
return s
#create a raw socket
try:
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
except socket.error , msg:
print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
# tell kernel not to put in headers, since we are providing it
s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
# now start constructing the packet
packet = '';
source_ip = '192.168.0.13'
dest_ip = '192.168.0.1' # or socket.gethostbyname('www.google.com')
# ip header fields
ihl = 5
version = 4
tos = 0
tot_len = 20 + 20 # python seems to correctly fill the total length, dont know how ??
id = 54321 #Id of this packet
frag_off = 0
ttl = 255
protocol = socket.IPPROTO_TCP
check = 10 # python seems to correctly fill the checksum
saddr = socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to
daddr = socket.inet_aton ( dest_ip )
ihl_version = (version << 4) + ihl
# the ! in the pack format string means network order
ip_header = pack('!BBHHHBBH4s4s' , ihl_version, tos, tot_len, id, frag_off, ttl, protocol, check, saddr, daddr)
# tcp header fields
source = 1234 # source port
dest = 80 # destination port
seq = 0
ack_seq = 0
doff = 5 #4 bit field, size of tcp header, 5 * 4 = 20 bytes
#tcp flags
fin = 0
syn = 1
rst = 0
psh = 0
ack = 0
urg = 0
window = socket.htons (5840) # maximum allowed window size
check = 0
urg_ptr = 0
offset_res = (doff << 4) + 0
tcp_flags = fin + (syn << 1) + (rst << 2) + (psh <<3) + (ack << 4) + (urg << 5)
# the ! in the pack format string means network order
tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags, window, check, urg_ptr)
# pseudo header fields
source_address = socket.inet_aton( source_ip )
dest_address = socket.inet_aton(dest_ip)
placeholder = 0
protocol = socket.IPPROTO_TCP
tcp_length = len(tcp_header)
psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length);
psh = psh + tcp_header;
tcp_checksum = checksum(psh)
# make the tcp header again and fill the correct checksum
tcp_header = pack('!HHLLBBHHH' , source, dest, seq, ack_seq, offset_res, tcp_flags, window, tcp_checksum , urg_ptr)
# final full packet - syn packets dont have any data
packet = ip_header + tcp_header
#Send the packet finally - the port specified has no effect
while True:
s.sendto(packet, (dest_ip , 80))
And when I run it, I get this error:
File "tcp-syn.py", line 98, in <module>
s.sendto(packet, (dest_ip , 80))
socket.error: [Errno 22] Invalid argument
Any help would be appreciated!

Porting a python 2 code to Python 3: ICMP Scan with errors

import random
import socket
import time
import ipaddress
import struct
from threading import Thread
def checksum(source_string):
sum = 0
count_to = (len(source_string) / 2) * 2
count = 0
while count < count_to:
this_val = ord(source_string[count + 1]) * 256 + ord(source_string[count])
sum = sum + this_val
sum = sum & 0xffffffff
count = count + 2
if count_to < len(source_string):
sum = sum + ord(source_string[len(source_string) - 1])
sum = sum & 0xffffffff
sum = (sum >> 16) + (sum & 0xffff)
sum = sum + (sum >> 16)
answer = ~sum
answer = answer & 0xffff
answer = answer >> 8 | (answer << 8 & 0xff00)
return answer
def create_packet(id):
header = struct.pack('bbHHh', 8, 0, 0, id, 1)
data = 192 * 'Q'
my_checksum = checksum(header + data)
header = struct.pack('bbHHh', 8, 0, socket.htons(my_checksum), id, 1)
return header + data
def ping(addr, timeout=1):
try:
my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
except Exception as e:
print (e)
packet_id = int((id(timeout) * random.random()) % 65535)
packet = create_packet(packet_id)
my_socket.connect((addr, 80))
my_socket.sendall(packet)
my_socket.close()
def rotate(addr, file_name, wait, responses):
print ("Sending Packets", time.strftime("%X %x %Z"))
for ip in addr:
ping(str(ip))
time.sleep(wait)
print ("All packets sent", time.strftime("%X %x %Z"))
print ("Waiting for all responses")
time.sleep(2)
# Stoping listen
global SIGNAL
SIGNAL = False
ping('127.0.0.1') # Final ping to trigger the false signal in listen
print (len(responses), "hosts found!")
print ("Writing File")
hosts = []
for response in sorted(responses):
ip = struct.unpack('BBBB', response)
ip = str(ip[0]) + "." + str(ip[1]) + "." + str(ip[2]) + "." + str(ip[3])
hosts.append(ip)
file = open(file_name, 'w')
file.write(str(hosts))
print ("Done", time.strftime("%X %x %Z"))
def listen(responses):
global SIGNAL
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
s.bind(('', 1))
print ("Listening")
while SIGNAL:
packet = s.recv(1024)[:20][-8:-4]
responses.append(packet)
print ("Stop Listening")
s.close()
SIGNAL = True
responses = []
ips = '200.131.0.0/20' # Internet network
wait = 0.002 # Adjust this based in your bandwidth (Faster link is Lower wait)
file_name = 'log1.txt'
ip_network = ipaddress.ip_network(unicode(ips), strict=False)
t_server = Thread(target=listen, args=[responses])
t_server.start()
t_ping = Thread(target=rotate, args=[ip_network, file_name, wait, responses])
t_ping.start()
I tried:
ip_network = ipaddress.ip_network( ips, strict=False) instead of ip_network = ipaddress.ip_network(unicode(ips), strict=False)
because of the error: ""NameError: name 'unicode' is not defined"
after:
I got: my_checksum = checksum(header + data) -> TypeError: can't concat bytes to str
so I tried:
data = bytes(192 * 'Q').encode('utf8') instead of data = 192 * 'Q'
Now, the error is : ""data = bytes (192 * 'Q').encode('utf8') TypeError: string argument without an encoding"
Could anyone help me to port the code to Python 3 ?

import random
import socket
import time
import ipaddress
import struct
from threading import Thread
def checksum(source_string):
sum = 0
count_to = (len(source_string) / 2) * 2
count = 0
while count < count_to:
this_val = source_string[count + 1] * 256 + source_string[count]
sum = sum + this_val
sum = sum & 0xffffffff
count = count + 2
if count_to < len(source_string):
sum = sum + source_string[len(source_string) - 1]
sum = sum & 0xffffffff
sum = (sum >> 16) + (sum & 0xffff)
sum = sum + (sum >> 16)
answer = ~sum
answer = answer & 0xffff
answer = answer >> 8 | (answer << 8 & 0xff00)
return answer
def create_packet(id):
header = struct.pack('bbHHh', 8, 0, 0, id, 1)
data = 192 * b'Q'
my_checksum = checksum(header + data)
header = struct.pack('bbHHh', 8, 0, socket.htons(my_checksum), id, 1)
return header + data
def ping(addr, timeout=1):
try:
my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
except Exception as e:
print (e)
packet_id = int((id(timeout) * random.random()) % 65535)
packet = create_packet(packet_id)
my_socket.connect((addr, 80))
my_socket.sendall(packet)
my_socket.close()
def rotate(addr, file_name, wait, responses):
print ("Sending Packets", time.strftime("%X %x %Z"))
for ip in addr:
ping(str(ip))
time.sleep(wait)
print ("All packets sent", time.strftime("%X %x %Z"))
print ("Waiting for all responses")
time.sleep(2)
# Stoping listen
global SIGNAL
SIGNAL = False
ping('127.0.0.1') # Final ping to trigger the false signal in listen
print (len(responses), "hosts found!")
print ("Writing File")
hosts = set()
for response in sorted(responses):
ip = struct.unpack('BBBB', response)
ip = str(ip[0]) + "." + str(ip[1]) + "." + str(ip[2]) + "." + str(ip[3])
hosts.add(ip)
with open(file_name, 'w') as file:
file.write('\n'.join(sorted(hosts, key=lambda item: socket.inet_aton(item))))
print ("Done", time.strftime("%X %x %Z"))
def listen(responses):
global SIGNAL
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
s.bind(('', 1))
print ("Listening")
while SIGNAL:
packet = s.recv(1024)[:20][-8:-4]
responses.append(packet)
print ("Stop Listening")
s.close()
SIGNAL = True
responses = []
ips = '192.168.1.0/28' # Internet network
wait = 0.002 # Adjust this based in your bandwidth (Faster link is Lower wait)
file_name = 'log1.txt'
ip_network = ipaddress.ip_network(ips, strict=False)
t_server = Thread(target=listen, args=[responses])
t_server.start()
t_ping = Thread(target=rotate, args=[ip_network, file_name, wait, responses])
t_ping.start()

Why my TCP packet doesn't seems like a TCP packet for protocol analyzers?

I am trying to use raw sockets to send a GET request to a server. I am using raw sockets so I can edit the Packet window size. Here is my code.
import socket, sys
from struct import *
def checksum(msg):
s = 0
for i in range(0, len(msg), 2):
w = ord(msg[i]) + (ord(msg[i+1]) << 8 )
s = s + w
s = (s>>16) + (s & 0xffff);
s = s + (s >> 16);
s = ~s & 0xffff
return s
#create a raw socket
try:
s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
except socket.error , msg:
print 'Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
# tell kernel not to put in headers, since we are providing it, when using IPPROTO_RAW this is not necessary
# s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)
packet = '';
source_ip = '192.168.2.7'
dest_ip = '216.86.145.50' # or socket.gethostbyname('www.google.com')
# ip header fields
ip_ihl = 5
ip_ver = 4
ip_tos = 0
ip_tot_len = 0 # kernel will fill the correct total length
ip_id = 54321 #Id of this packet
ip_frag_off = 0
ip_ttl = 255
ip_proto = socket.IPPROTO_TCP
ip_check = 0 # kernel will fill the correct checksum
ip_saddr = socket.inet_aton ( source_ip ) #Spoof the source ip address if you want to
ip_daddr = socket.inet_aton ( dest_ip )
ip_ihl_ver = (ip_ver << 4) + ip_ihl
ip_header = pack('!BBHHHBBH4s4s' , ip_ihl_ver, ip_tos, ip_tot_len, ip_id, ip_frag_off, ip_ttl, ip_proto, ip_check, ip_saddr, ip_daddr)
# tcp header fields
tcp_source = 1234 # source port
tcp_dest = 80 # destination port
tcp_seq = 454
tcp_ack_seq = 0
tcp_doff = 5
#tcp flags
tcp_fin = 0
tcp_syn = 1
tcp_rst = 0
tcp_psh = 0
tcp_ack = 0
tcp_urg = 0
tcp_window = socket.htons (2048)
tcp_check = 0
tcp_urg_ptr = 0
tcp_offset_res = (tcp_doff << 4) + 0
tcp_flags = tcp_fin + (tcp_syn << 1) + (tcp_rst << 2) + (tcp_psh <<3) + (tcp_ack << 4) + (tcp_urg << 5)
tcp_header = pack('!HHLLBBHHH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags, tcp_window, tcp_check, tcp_urg_ptr)
user_data = "GET / HTTP/1.1\r\nHost:www.example.com\n\nUser-Agent:Mozilla 5.0\r\n\r\n"
source_address = socket.inet_aton( source_ip )
dest_address = socket.inet_aton(dest_ip)
placeholder = 0
protocol = socket.IPPROTO_TCP
tcp_length = len(tcp_header) + len(user_data)
psh = pack('!4s4sBBH' , source_address , dest_address , placeholder , protocol , tcp_length);
psh = psh + tcp_header + user_data;
tcp_check = checksum(psh)
tcp_header = pack('!HHLLBBH' , tcp_source, tcp_dest, tcp_seq, tcp_ack_seq, tcp_offset_res, tcp_flags, tcp_window) + pack('H' , tcp_check) + pack('!H' , tcp_urg_ptr)
packet = ip_header + tcp_header + user_data
s.sendto(packet, (dest_ip , 0 ))
I am using Wireshark to view the packet being sent. The problem is the output is not a TCP GET request packet. In wire shark the output is the white in colour, under protocol it says IPv4 and info says: 144 Unknown(255). How do I fix this?

Like #Sivir said you need to establish a three way handshake because you want to use the TCP protocol. In theory the handshake should look like this
YourProgram: sends a SYN packet
Server: sends SYNACK packet
YourProgram: sends a ACK packet
More information regarding this can be found here.

It's because you send one single packet, but in TCP you have to setup connection first (3 ways handshake), then send request and then close connection.
Although it is possible to implement it using raw socket, there is a few parameters that you need to control during connection. If you tell why do you need to control window size, may be there is way to do it without TCP protocol implementation.