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Peer.py
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Peer.py
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import socket
import sys
import threading
from _thread import *
from datetime import datetime
from time import sleep
ADDRESS = '127.0.1.1'
BASE_PORT = 60000
BUFF_SIZE = 512
RES_OK = 'OK'
RES_INVALID = 'INVALID'
SLEEP_TIME = 5
NUM_OF_MSGS = 7
USERNAME = 'bilkentstu'
PASS = 'cs421s2021'
class Peer:
def __init__(self, addr: str, pid: int) -> None:
self.addr = addr
self.pid = pid
self.peers = self.get_pids()
self.connections: list[socket.socket] = []
self.forwarded_msgs: dict[str] = {}
self.lock = threading.Lock()
def run(self):
"""
Runs the server as the main thread and client in a new thread.
"""
threading.Thread(target=self.server).start()
threading.Thread(target=self.client).start()
# self.server()
def server(self):
"""
Handles the server side of peer.\n
Sever listens for incoming connection and creates
a new thread for each client.
"""
sock = self.create_socket()
address = (ADDRESS, BASE_PORT + self.pid)
sock.bind(address)
sock.listen(1)
while True:
conn, addr = sock.accept()
threading.Thread(target=self.client_handler, args=(conn, )).start()
def client_handler(self, conn: socket.socket):
"""
Handles requests from the given connection.
Parameters
----------
conn: socket The TCP connection.
"""
while True:
data: bytes = conn.recv(BUFF_SIZE)
if data:
msg: str = data.decode('ascii').strip()
msg_details = msg.split(' ')
req_code = msg_details[0]
if req_code == 'FLOD':
threading.Thread(target=self.forward, args=(msg, )).start()
elif req_code == 'USER':
if msg_details[1] == USERNAME:
self.send_msg(f'{RES_OK} Success\r\n', conn)
else:
self.send_msg(
f'{RES_INVALID} Invalid username!\r\n', conn)
elif req_code == 'PASS':
if msg_details[1] == PASS:
self.send_msg(f'{RES_OK} Success\r\n', conn)
else:
self.send_msg(
f'{RES_INVALID} Invalid password!\r\n', conn)
elif req_code == 'EXIT':
conn.close()
break
def client(self):
"""
Handles the client side of this peer.
Connects to other peers based on the toplogy.
Client side floods the network every 5 seconds for 7 times.
Closes connections after flooding is finished.
"""
sleep_time = 60 - datetime.utcnow().second
self.connect_to_peers(sleep_time)
print(f'Waiting till next minute ({sleep_time}s)...')
sleep(sleep_time)
self.flood()
self.shutdown()
self.print_stats()
def connect_to_peers(self, sleep_time) -> None:
"""
Connects and authenticates to the peers with peer ids
extracted from the topology.
No further action is taken in case of failure.
After an attempt to connect and authenticate, the peer
id is removed from the list of peers
"""
last_sec_to_try = 2
while len(self.peers) > 0:
for pid in self.peers:
sock = self.create_socket()
try:
res = sock.connect_ex((ADDRESS, BASE_PORT + pid))
if res != 0:
print("[RES] ------> " + str(res))
break
self.connections.append(sock)
print(
f'TCP connection established with peer {pid}.')
success, status_text = self.authenticate(sock)
if success:
print(f'Authenticated to peer {pid}')
else:
print(f'Failed to authenticate to peer {pid}')
print(f'Response: {status_text}')
self.peers.remove(pid)
except Exception as e:
print("[EXCEPTION ] -------------")
pass
# self.peers.remove(pid)
# Retry to connect to the peers that are not
# up until 2 seconds before the next minute mark
last_sec_to_try -= 1
if last_sec_to_try <= 0:
break
def flood(self):
"""
Sends the peer's id with timestamp to all
of the connected peers after every 5 seconds
"""
for _ in range(NUM_OF_MSGS):
flood_time = datetime.now().strftime('%H:%M:%S')
for conn in self.connections:
msg = f'FLOD {self.pid} {flood_time}'
self.send_msg(msg, conn)
sleep(SLEEP_TIME)
def forward(self, msg: str):
"""
Forwards the given message to all peers (if not already forwarded).
If message is already forwarded, it increments its counter in the
forwarded messages list.
Parameters
----------
msg: str -> The message to be forwarded.
"""
self.lock.acquire(blocking=True)
is_forwarded = self.forwarded_msgs.__contains__(msg)
self.lock.release()
if not is_forwarded:
print(f'Received -> {msg} [FORWARD]')
for conn in self.connections:
self.send_msg(msg, conn)
self.lock.acquire(blocking=True)
self.forwarded_msgs[msg] = 1
self.lock.release()
else:
print(f'Received -> {msg} [DON\'T FORWARD]')
self.lock.acquire(blocking=True)
self.forwarded_msgs[msg] += 1
self.lock.release()
def authenticate(self, sock: socket.socket):
"""
Authenticates to the peer of the given connection.
Parameters
----------
sock: socket -> Peer connection.
Returns
-------
True, status_text: -> On success.
False, status_text: -> On failure.
"""
self.send_msg(f'USER {USERNAME}\r\n', sock)
response = sock.recv(BUFF_SIZE)
response = response.decode().strip()
index = response.index(' ')
status_code = response[: index]
status_text = response[index:]
if status_code != RES_OK:
return False, status_text
self.send_msg(f'PASS {PASS}\r\n', sock)
response = sock.recv(BUFF_SIZE)
response = response.decode().strip()
index = response.index(' ')
status_code = response[: index]
status_text = response[index:]
if status_code != RES_OK:
return False, status_text
return True, status_text
def shutdown(self):
"""
Closes connection to all peers.
"""
for conn in self.connections:
msg = 'EXIT\r\n'
self.send_msg(msg, conn)
conn.close()
def create_socket(self):
"""
Creates a socket object.
"""
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
return sock
def send_msg(self, msg: str, sock: socket.socket):
"""
Sends the given message through the given connection.
Parameters
----------
msg: str -> Message to be sent.
sock: socket -> The connection.
"""
try:
msg = msg.encode('ascii')
sock.sendall(msg)
except Exception as e:
print("Failed to send message to peer")
def get_pids(self):
"""
Parses the peer ids from the toplogy that this peer should initiate a TCP connection with.
Return
------
peers: list -> Ids of peers.
"""
peers = []
with open('OverlayNetworkTopology.txt', 'r') as f:
# Number of peers
n = f.readline().strip().replace(r'\r\n', '')
for line in f.readlines():
stripped_line = line.rstrip().replace(r'\r\n', '')
src, dst = stripped_line.split('->')
if int(src) == self.pid:
peers.append(int(dst))
return peers
def print_stats(self):
print('-' * 20 + f'PEER-{self.pid}' + '-' * 20)
for msg, count in self.forwarded_msgs.items():
message = msg.split(' ')
# _, src_id, timestamp = msg.split(' ')
print(f'{message[1]}\t\t{message[2]}\t\t{count}')
def parse_args(name="default", addr="127.0.1.1", peer_id=1):
return addr, int(peer_id)
if __name__ == '__main__':
addr, pid = parse_args(*sys.argv)
peer = Peer(ADDRESS, pid)
peer.run()