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client.py
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client.py
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from uuid import getnode as get_mac
from random import uniform
from utils import *
import time
import threading
class DHCPClient:
def __init__(self):
self.MAC = str(hex(get_mac()))[2:]
self.hostname = input('Hostname: ')
self.packet = b''
self.transaction_ID = create_transaction_ID()
self.IP = '0.0.0.0'
self.offered_IP = ''
self.fix_lease_time = '0'
self.lease_time = '0'
self.subnet_mask = '0.0.0.0'
self.router = ''
self.DNS = []
self.DHCPServer_ID = ''
self.gateway_IP = ''
self.ack = False
self.offer = False
self.backoff_cutoff = 120
self.initial_interval = 10
self.dis_sent_time = 0
def show(self):
print('Client configuration:')
print('Hostname: {} | MAC: {} | IP: {} | Lease Time: {} | DNS : {}'
.format(self.hostname, mac_split(self.MAC), self.IP, self.lease_time, self.DNS))
print()
def DHCPReceive(self, data):
if data[4:8] == self.transaction_ID:
if data[242] == 2:
self.offer = True
self.offered_IP = '.'.join(map(lambda x: str(x), data[16:20]))
self.gateway_IP = '.'.join(map(lambda x: str(x), data[20:24]))
self.subnet_mask = '.'.join(map(lambda x: str(x), data[245:249]))
self.router = '.'.join(map(lambda x: str(x), data[251:255]))
self.DNS = []
for i in range(0, 8, 4):
self.DNS.append('.'.join(map(lambda x: str(x), data[257 + i:257 + i + 4])))
self.DHCPServer_ID = '.'.join(map(lambda x: str(x), data[273:277]))
elif data[242] == 5:
self.IP = '.'.join(map(lambda x: str(x), data[16:20]))
self.lease_time = str(int(binascii.hexlify(data[267:271]), 16))
self.fix_lease_time = self.lease_time
self.ack = True
def discover_timer(self, start):
current_time = int(time.time())
if current_time - start > self.initial_interval and self.IP == '0.0.0.0':
x = uniform(0.5, 1)
new_interval = self.initial_interval * 2 * x
if new_interval < self.backoff_cutoff and self.initial_interval != self.backoff_cutoff:
self.initial_interval = new_interval
else:
self.initial_interval = self.backoff_cutoff
return True
return False
def DHCPBody(self):
packet = b''
packet += b'\x01'
packet += b'\x01'
packet += b'\x06'
packet += b'\x00'
packet += self.transaction_ID
packet += b'\x00\x00'
packet += b'\x80\x00'
packet += b'\x00\x00\x00\x00'
packet += b'\x00\x00\x00\x00'
packet += b'\x00\x00\x00\x00'
packet += b'\x00\x00\x00\x00'
packet += mac_to_bytes(self.MAC)
packet += b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
packet += b'\x00' * 64
packet += b'\x00' * 128
packet += b'\x63\x82\x53\x63'
return packet
def DHCPDiscover(self):
packet = self.DHCPBody()
# options
packet += b'\x35\x01\x01'
packet += b'\x3d\x06' + mac_to_bytes(self.MAC)
packet += b'\x37\x03\x01\x03\x06'
packet += b'\x0c' + nameLen_to_hex(self.hostname) + name_to_hex(self.hostname)
packet += b'\xff'
self.packet = packet
def DHCPRequest(self):
packet = self.DHCPBody()
# options
packet += b'\x35\x01\x03'
packet += b'\x3d\x06' + mac_to_bytes(self.MAC)
packet += b'\x32\x04' + ip_to_hex(self.offered_IP)
packet += b'\x36\x04' + ip_to_hex(self.DHCPServer_ID)
packet += b'\x37\x03\x01\x03\x06'
packet += b'\x0c' + nameLen_to_hex(self.hostname) + name_to_hex(self.hostname)
packet += b'\xff'
self.packet = packet
def main():
dhcpClient = DHCPClient()
with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as skt:
skt.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
skt.settimeout(20)
try:
skt.bind((dhcpClient.IP, 68))
# port = randint(1024, 5000)
# skt.bind((dhcpClient.IP, port))
except Exception as e:
print(e)
skt.close()
exit()
dhcpClient.DHCPDiscover()
skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
print('\n[Socket] DHCP Discover Sent\n')
dhcpClient.dis_sent_time = int(time.time())
thread = threading.Thread(target=timer, args=(dhcpClient, skt))
thread.start()
while True:
try:
data = skt.recv(1024)
dhcpClient.DHCPReceive(data)
if dhcpClient.offer:
dhcpClient.DHCPRequest()
skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
print('\n[Socket] DHCP Request Sent\n')
dhcpClient.offer = False
if dhcpClient.ack:
if dhcpClient.IP == '0.0.0.0':
print('\n[Socket] DHCP Ack Received\n')
dhcpClient.show()
dhcpClient.ack = False
except socket.timeout:
if dhcpClient.offer:
dhcpClient.ack = False
dhcpClient.offer = False
dhcpClient.DHCPDiscover()
skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
dhcpClient.dis_sent_time = int(time.time())
print('[Socket Timeout] Discover Sent Again\n')
def timer(dhcpClient, skt):
while True:
# TICK THE LEASE TIME
time.sleep(1)
if int(dhcpClient.lease_time) > 0:
dhcpClient.show()
dhcpClient.lease_time = str(int(dhcpClient.lease_time) - 1)
if int(dhcpClient.lease_time) == 0:
print('[EXPIRED]')
# RENEWING AND REBINDING 'TILL EXPIRED
if dhcpClient.IP != '0.0.0.0':
if int(dhcpClient.lease_time) == 0:
pass
# elif int(dhcpClient.lease_time) == int(dhcpClient.fix_lease_time) / 2:
# dhcpClient.DHCPRequest()
# skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
# print('[RENEWING]\n[Socket] DHCP Request Sent\n')
# elif int(dhcpClient.lease_time) <= int(int(dhcpClient.fix_lease_time) * 1/8):
# dhcpClient.DHCPDiscover()
# skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
# dhcpClient.dis_sent_time = int(time.time())
# print('[REBINDING]\n[Socket] Discover Sent Again\n')
# DHCP DISCOVER TIMEOUT
current_time = int(time.time())
if current_time - dhcpClient.dis_sent_time > dhcpClient.initial_interval:
if dhcpClient.IP == '0.0.0.0' or int(dhcpClient.lease_time) == 0:
x = uniform(0.5, 1)
new_interval = dhcpClient.initial_interval * 2 * x
if new_interval < dhcpClient.backoff_cutoff and dhcpClient.initial_interval != dhcpClient.backoff_cutoff:
dhcpClient.initial_interval = int(new_interval)
else:
dhcpClient.initial_interval = dhcpClient.backoff_cutoff
print('\n[Discover Timeout] Discover Sent Again\nNew Interval: {}\n'
.format(dhcpClient.initial_interval))
dhcpClient.ack = False
dhcpClient.offer = False
dhcpClient.DHCPDiscover()
skt.sendto(dhcpClient.packet, ('<broadcast>', 67))
dhcpClient.dis_sent_time = int(time.time())
if __name__ == '__main__':
main()