I recently bought the book Black Hat Python, 2nd Edition, by Justin Seitz, which seems to be a very good book about networking and all that (i am writing my code on Kali Linux)
I have a problem on the TCP Proxy Tool on chapter 2 :
Here is the code :
import sys
import socket
import threading
HEX_FILTER = ''.join(
[(len(repr(chr(i))) == 3) and chr(i) or '.' for i in range(256)])
def hexdump(src, length = 16, show = True):
# basically translates hexadecimal characters to readable ones
if isinstance(src, bytes):
src = src.decode()
results = list()
for i in range(0, len(src), length):
word = str(src[i:i+length])
printable = word.translate(HEX_FILTER)
hexa = ' '.join(['{ord(c):02X}' for c in word])
hexwidth = length*3
results.append('{i:04x} {hexa:<{hexwidth}} {printable}')
if show :
for line in results :
print(line)
else :
return results
def receive_from(connection):
buffer = b""
connection.settimeout(10)
try :
while True :
data = connection.recvfrom(4096)
if not data :
break
buffer += data
except Exception as e:
pass
return buffer
def request_handler(buffer):
# perform packet modifications
return buffer
def response_handler(buffer):
# perform packet modifications
return buffer
def proxy_handler(client_socket, remote_host, remote_port, receive_first):
remote_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
remote_socket.connect((remote_host, remote_port))
if receive_first :
# Check for any data to receive before
going into the main loop (i guess)
remote_buffer = receive_from(remote_socket)
hexdump(remote_buffer)
remote_buffer = response_handler(remote_buffer)
if len(remote_buffer):
print("[<==] Sending %d bytes to localhost." % len(remote_buffer))
client_socket.send(remote_buffer)
while True : # Start the loop
local_buffer = receive_from(client_socket)
if len(local_buffer):
line = "[==>] Received %d bytes from localhost." % len(local_buffer)
print(line)
hexdump(local_buffer)
local_buffer = request_handler(local_buffer)
remote_socket.send(local_buffer)
print("[==>] Sent to remote.")
remote_buffer = receive_from(remote_socket)
if len(remote_buffer):
print("[==>] Received %d bytes from remote." % len(remote_buffer))
hexdump(remote_buffer)
remote_buffer=response_handler(remote_buffer)
client_socket.send(remote_buffer)
print("[<==] Sent to localhost.")
if not len(local_buffer) or not len(remote_buffer):
# If no data is passed, close the sockets and breaks the loop
client_socket.close()
remote_socket.close()
print("[*] No more data. Closing connections. See you later !")
break
def server_loop(local_host, local_port, remote_host, remote_port, receive_first):
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try :
server.bind((local_host, local_port)) # Bind the local host and the local port
except Exception as e:
print('Problem on bind : %r' %e)
# If an error occurs, prints a
print("[!] Failed to listen on %s:%d" % (local_host, local_port))
print("[!] Check for other listening sockets or correct permissions.")
sys.exit(0)
print("[*] Listening on %s:%d" % (local_host, local_port))
server.listen(5)
while True :
client_socket, addr = server.accept()
# print out the local connection information
line = "> Received incoming connection from %s:%d" % (addr[0], addr[1])
print(line)
# start a thread to talk to the remote host
proxy_thread = threading.Thread(
target = proxy_handler,
args=(client_socket,remote_host,
remote_port, receive_first))
proxy_thread.start()
def main():
if len(sys.argv[1:]) != 5:
print("Usage: ./proxy.py [localhost] [localport]")
print("[remotehost] [remoteport] [receive_first]")
print("Example : ./proxy.py 127.0.0.1 9000 192.168.56.1 9000 True")
sys.exit(0)
loca l_host = sys.argv[1]
local_port = int(sys.argv[2])
remote_host = sys.argv[3]
remote_port = int(sys.argv[4])
receive_first = sys.argv[5]
if "True" in receive_first:
receive_first = True
else :
receive_first = False
server_loop(local_host, local_port,
remote_host, remote_port, receive_first)
if __name__ == '__main__':
main()
(sorry, i had a bit of a trouble formatting it and it's quite long)
Now, normally, i just need to open 2 terminals and run the code with the command line :
sudo python proxy.py 127.0.0.1 21 ftp.dlptest.com 21 True
in one terminal, and :
ftp 127.0.0.1 21
in the other one.
My code seems to be working fine, except that... I receive no data. I tried different ftp servers (notice that i don't use the one quoted in the book), but it still doesn't work. It just says :
[*] Listening on 127.0.0.1
> Received incoming connection from 127.0.0.1:55856
but it doesn't actually displays anything until the connexion times out or that i stop the command with Ctrl + C.
I know this question has already been asked, but they don't resolve my problem.
Please tell me if i forgot a line of code (for example the one that prints the data on the screen lol) or did anything wrong :)
one the hexa variable you need to put and f'{ord(c):02x}' because you just have a string and not using the 'c' variable from the list comprehension. That's a small typo you missed fix that and try the whole process again.
hexa = ' '.join([f'{ord(c):02X}' for c in word])
The f should be here ^
Related
I'm working on a program that receives a string from an Android app sent through WiFi, the program was originally written for Python 2.7, but after adding some additional functionalities I changed it to Python 3.7. However, after making that change, my data had an extra letter at the front and for the life of me I can't figure out why that is.
Here's a snippet of my code, it's a really simple if statement to see which command was sent from the Android app and controls Raspberry Pi (4) cam (v.2) with the command.
This part sets up the connections and wait to see which command I send.
isoCmd = ['auto','100','200','300','400','500','640','800']
HOST = ''
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
brightness = 50
timelapse = 0
tcpSerSock = socket(AF_INET, SOCK_STREAM)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(5)
while True:
print ('Waiting for connection')
tcpCliSock,addr = tcpSerSock.accept()
try:
while True:
data = ''
brightness = ' '
data = tcpCliSock.recv(BUFSIZE)
dataStr = str(data[1:])
print ("Here's data ",dataStr)
if not data:
break
if data in isoCmd:
if data == "auto":
camera.iso = 0
print ('ISO: Auto')
else:
camera.iso = int(data)
print ('ISO: '), data
When I start the program this is what I see:
Waiting for connection
#If I send command '300'
Here's data b'300'
Here's data b''
Waiting for connection
I'm not sure why there's the extra b'' is coming from. I have tested the code by just adding the "b" at the beginning of each items in the array which worked for any commands that I defined, not for any commands to control the Pi camera since well, there's no extra b at the beginning. (Did that make sense?) My point is, I know I'm able to send commands no problem, just not sure how to get rid of the extra letter. If anyone could give me some advice that would be great. Thanks for helping.
Byte strings are represented by the b-prefix.
Although you can see the string in output on printing, inherently they are bytes.
To get a normal string out of it, decode function can help.
dataStr.decode("utf-8")
b'data' simply means the data inside quotes has been received in bytes form, as mentioned in other answers also, you have to decode that with decode('utf-8') to get it in string form.
I have updated your program below, to be compatible for v3.7+
from socket import *
isoCmd = ['auto','100','200','300','400','500','640','800']
HOST = ''
PORT = 21567
BUFSIZE = 1024
ADDR = (HOST,PORT)
brightness = 50
timelapse = 0
tcpSerSock = socket(AF_INET, SOCK_STREAM)
tcpSerSock.bind(ADDR)
tcpSerSock.listen(5)
while True:
print ('Waiting for connection')
tcpCliSock,addr = tcpSerSock.accept()
try:
while True:
data = ''
brightness = ' '
data = tcpCliSock.recv(BUFSIZE).decode('utf-8')
print ("Here's data "+data)
if not data:
break
if data in isoCmd:
if data == "auto":
camera.iso = 0
print ('ISO: Auto')
else:
camera.iso = int(data)
print ('ISO: '+ data)
except Exception as e:
print(e)
My Python script is not working properly. It says that kandicraft.finlaydag33k.nl on port 25565 is down, whilst, it's responding to pings (and I can connect to the game itself)
I know it should be a bug somewhere in the code, but I can't find it as I started python like half an hour ago.
The output that I get is: 24-02-2016 16:05:30] kandicraft.finlaydag33k.nl on port 25565 seems to be unreachable!
I've editted the question as the port 80 with google now works, but the main purpose of this script (pinging minecraft servers) later on doesn't.
the error I get from the exception is an integer is required (so port 25565 doesn't seem to be an integer???)
import os
import RPi.GPIO as gpio
import time
import socket
## set variables for the machine to ping and pin for the LED
hostname = ['kandicraft.finlaydag33k.nl:25565','google.com:80']
led_pin = 37
## prepare
led_status = gpio.LOW
gpio.setmode(gpio.BOARD)
gpio.setup(led_pin, gpio.OUT, gpio.PUD_OFF, led_status)
## PING FUNCTION GALORE!!
def check_ping(host,port):
captive_dns_addr = ""
host_addr = ""
try:
host_addr = socket.gethostbyname(host)
if (captive_dns_addr == host_addr):
return False
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(1)
s.connect((host,port))
s.close()
except:
return False
return True
## Run the script itself infinitely
while True:
host_up = ""
for host in hostname:
if ":" in host:
temphost, tempport = host.split(":")
pingstatus = check_ping(temphost, tempport)
if pingstatus == False:
print('[' + time.strftime("%d-%m-%Y %H:%M:%S") + '] ' + temphost + ' on port ' + tempport + ' seems to be unreachable!')
host_up = "False"
if host_up == "False":
led_status = gpio.HIGH
else:
led_status = gpio.LOW
gpio.output(led_pin,led_status)
time.sleep(1)
I managed to solve all issues that I found by using check_ping(temphost,int(tempport))
thanks all for helping me solve it!
To debug your program just replace
except:
return False
by:
except Exception as exc:
print exc
return False
in check_ping() function
I'm currently trying to write process that embeds a sequence of n IPs into packets and send it off to n server. Each server remove the outermost IP and then forward it to said IP. This is exactly like tunneling I know. During the process I also want the server to do a traceroute to where it's forwarding the packet and send that back to the previous server.
My code currently will forward the packets but it's stuck on performing the traceroute and getting it. I believe it's currently stuck in the while loop in the intermediate server. I think it's having something to do with me not closing the sockets properly. Any suggestion?
Client
#!/usr/bin/env python
import socket # Import socket module
import sys
import os
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 17353 # Reserve a port
FILE = raw_input("Enter filename: \n ")
NIP = raw_input("Enter Number of IPs: ")
accepted_IP = 0
IP= []
while accepted_IP < int(NIP):
IP.append(raw_input("Enter destination IP: \n"))
accepted_IP +=1
#cIP = raw_input("Enter intemediate IP: \n ")
ipv = raw_input("Enter IP version... 4/6")
try:
s.connect((host, port))
print "Connection sucessful!"
except socket.error as err:
print "Connection failed. Error: %s" %err
quit()
raw = open(FILE,"rb")
size = os.stat(FILE).st_size
ls = ""
buf = 0
for i in IP:
while len(i) < 15:
i += "$"
ls += i
header = ipv+NIP+ls+FILE
print ls
s.sendall(header + "\n")
print "Sent header"
data = raw.read(56) +ipv + NIP + ls
print "Begin sending file"
while buf <= size:
s.send(data)
print data
buf += 56
data = raw.read(56) + ipv + NIP + ls
raw.close()
print "Begin receiving traceroute"
with open("trace_log.txt","w") as tracert:
trace = s.recv(1024)
while trace:
treacert.write(trace)
if not trace: break
trace = s.recv(1024)
print "finished forwarding"
s.close()
Intermediate server
#!/usr/bin/env python
import socket
import subprocess
srvsock = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
srvsock.bind( (socket.gethostname(), 17353) )
srvsock.listen( 5 ) # Begin listening with backlog of 5
# Run server
while True:
clisock, (remhost, remport) = srvsock.accept() #Accept connection
print
d = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
header = ""
while True:
b = clisock.recv(1)
if b == "\n":
break
header += b
num = 15 * int(header[1]) + 2
file_name = header[num:]
nheader = header[0]+ str(int(header[1])-1) + header[17:]
d.connect((socket.gethostname(), 12355))
d.sendall(nheader+'\n')
print "begin forwarding"
while True:
raw = clisock.recv(56 + num) # recieve data
ip = raw[-15:] # extract IP
ipv, NIP = raw[57] , str(int(raw[57])-1)
if NIP == "0":
while (raw):
print "stuck in this loop"
d.send(raw[:56])
raw=clisock.recv(56+num)
if not raw: break
else:
while (raw):
print raw[:57] + NIP + raw[59:-15]
print "\n"
d.send(raw[:57] + NIP + raw[59:-15])
raw = clisock.recv(56+num)
if not raw :break
print "Finish forwarding"
d.close()
break
print "Begin traceroute"
tracrt = subprocess.Popen(['traceroute','google.com'], stdout=subprocess.PIPE)
s.sendall(tracrt.communicate()[0])
print "Finished"
clisock.close()
s.close()
Destination server
import socket
s = socket.socket()
host = socket.gethostname()
port = 12355
s.bind((host,port))
s.listen(5)
while True:
csock, (client, cport) = s.accept()
print client
header = ""
while True:
b = csock.recv(1)
if b == "\n":
break
header += b
file_name = header[2:]
r = open("File_test_"+file_name,"wb")
print 'Opening file for writing'
while True:
print "Begin writing file" + " " + file_name
raw = csock.recv(56)
while (raw):
print raw
r.write(raw)
raw = csock.recv(56)
r.flush()
r.close()
print "finish writing"
break
print "closing connection"
csock.close()
s.close()
The intermediate server is stuck in clisock.recv() in this loop because the break condition not raw isn't met before the connection is closed by the client, and the client doesn't close the connection before receiving the traceroute from the intermediate server, so they are waiting on each other.
To remedy this, you might consider sending the file size to the intermediate server, so that it can be used to determine when the receive loop is done. Or, if your platform supports shutting down one half of the connection, you can use
s.shutdown(socket.SHUT_WR)
in the client after sending the file.
I don't know how to make the server to take the command from the user ... I have untill now this code for the server
import socket, sys
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#HOST = sys.argv.pop() if len(sys.argv) == 3 else '127.0.0.1'
HOST = 'localhost'
PORT = 8080
def recv_all(sock, length):
data = ''
while len(data) < length:
more = sock.recv(length - len(data)).decode()
if not more:
raise EOFError('socket closed %d bytes into a %d-byte message' %
(len(data), length))
data += more
return data
#if sys.argv[1:] == ['server']:
if True:
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((HOST, PORT))
s.listen(1)
while True:
print('Listening at', s.getsockname())
sc, sockname = s.accept()
print('We have accepted a connection from', sockname)
print('Socket connects', sc.getsockname(), 'and', sc.getpeername())
message = recv_all(sc, 16)
print('The incoming sixteen-octet message says', repr(message))
sc.sendall('Farewell, client'.encode())
This is the rest from srver-side and i can't get working it from here , in rest everything works perfect! ....
if repr(message) == 'exit':
sc.close()
print('Reply sent, socket closed')
else:
print(sys.stderr, 'usage: tcp_local.py server|client [host]')
And this code for the client
import socket, sys
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# HOST = sys.argv.pop() if len(sys.argv) == 3 else '127.0.0.1'
HOST = 'localhost'
PORT = 8080
def recv_all(sock, length):
data = ''
while len(data) < length:
more = sock.recv(length - len(data)).decode()
if not more:
raise EOFError('socket closed %d bytes into a %d-byte message'
% (len(data), length))
data += more
return data
#elif sys.argv[1:] == ['client']:
if True:
print('Connecting to server on: ',HOST,' Port: ',PORT)
s.connect((HOST, PORT))
print('Client has been assigned socket name', s.getsockname())
s.sendall('Hi there, server'.encode())
print('Hi there, server, has been send')
reply = recv_all(s, 16)
print('The server said', repr(reply))
command = (input('enter:').encode())
s.sendall(command)
if s.send(command) == 'exit':
s.close()
else:
print(sys.stderr, 'usage: tcp_local.py server|client [host]')
I can get the client to ask the user for input , and when I enter the string 'exit' (without the quotation marks) in the client side I don't know how to make the server read the raw text and convert it into close server function ... any help would be greatly appreciated ... have a nice Sunday everyone !
I get "Type error : 'str' does not support the buffer interface"
Everythong works fine now , I've added the .encode() at the command = (input('enter:').encode()) part . but how do i make the server to close after this ?
I am not sure of what I am saying but for what I know, if you are using python 3.x, you need to convert string to bytes before sending to through an socket. On the client you should do command = bytes(input('enter:'), "utf-8") and on the server you have to put it back as string so, message = recv_all(sc, 16).decode("utf-8"). Not tested...
I'm making a UDP program that connects multiple clients/neighbors. There is no server everyone is using the same program. I'm trying to test it with localhost so consider all IPs and ports of neighbors work as intended. Using 127.0.0.1 as IP on all and connecting to different ports.
So my question is why do I receive the startup data that I send before the while loop but I cannot send any? Seems that I am doing something wrong with sys.stdin.
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind((HOST, PORT))
going = True
input = [s]
while going:
i,o,e = select.select(input,[],[],)
try :
for x in i:
if x == sys.stdin:
data = sys.stdin.read()
for i in neighbors:
addr = (i[1][0], int(i[1][1]))
s.sendto(data, addr)
else:
msg, addr = s.recvfrom(100)
print msg
except socket.error, msg:
print 'Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
s.close()
input is always [s], so i is always going to be [s], so x == sys.stdin is never going to be True (because x is always s), so only the else clause will ever execute.
Maybe you meant input = [s, sys.stdin]?