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node.py
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node.py
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import socket
import threading
import struct
import binascii
import sys
from p2p import parseReceivedMessage, createMessage, ipToNum
# =============================================================================
# Script for creating a node for the P2P network.
# =============================================================================
# List of known neighbours
neighbours = []
# Distionary with key-value pairs
keys = {'ourtestkey': '12345678'}
# List of connections
connections = []
# Sequence number for header
sequence_nr = 0
# List of query searches
q_searches = []
# Different message types in binary
MSG_PING = 0x00
MSG_PONG = 0x01
MSG_BYE = 0x02
MSG_JOIN = 0x03
MSG_QUERY = 0x80
MSG_QHIT = 0x81
# Determine what kind of message has been received and process it accordingly
def process_message(header, payload, socket):
# Discard messages with invalid version or ttl
global q_searches
global connections
global neighbours
if (header[0] == 1 or header[1] < 1 or header[1] > 5):
if header[2] == MSG_PING:
# Type a
if header[1] == 1:
print("Respond with PONG A")
socket.send(createMessage(msg_type=MSG_PONG,
org_port=socket.getsockname()[1],
org_ip=socket.getsockname()[0]))
# Type b
else:
tmp = list(neighbours)
if (header[6], header[4]) in tmp:
tmp.remove((header[6], header[4]))
response = tmp[:5]
data = bytearray()
if(len(response) > 0):
data.extend(struct.pack('>HH', len(response), 0))
for item in response:
data.extend(struct.pack('>IHH', ipToNum(item[0]),
item[1], 0))
print("Respond with PONG B")
socket.send(createMessage(msg_type=MSG_PONG,
org_port=socket.getsockname()[1],
org_ip=socket.getsockname()[0],
payload=data))
elif header[2] == MSG_PONG:
# Pong type b
if len(payload) > 0:
# Iterate through payload
for i in range(1, len(payload)):
# Add to neighbours if not already there
if not (payload[i][0], payload[i][1]) in neighbours:
neighbours.append((payload[i][0], payload[i][1]))
elif header[2] == MSG_BYE:
if (header[6], header[4]) in neighbours:
neighbours.remove((header[6], header[4]))
print("Neighbours:")
print(neighbours)
if (header[6], socket) in connections:
connections.remove((header[6], socket))
elif header[2] == MSG_JOIN:
if not (header[6], header[4]) in neighbours:
neighbours.append((header[6], header[4]))
print("Neighbours:")
print(neighbours)
data = bytearray()
data.append(0x02)
data.append(0x00)
print("Respond with JOIN OK")
socket.send(createMessage(msg_type=MSG_JOIN,
org_port=socket.getsockname()[1],
org_ip=socket.getsockname()[0],
payload=data))
elif header[2] == MSG_QUERY:
# Check if key is known
if payload[0] in keys:
data = struct.pack('>HHHH4s', 1, 0, 1, 0,
binascii.unhexlify(keys[payload[0]]))
print("Respond with QUERY HIT")
socket.send(createMessage(msg_type=MSG_QHIT,
org_port=socket.getsockname()[1],
org_ip=socket.getsockname()[0],
payload=data, msg_id=header[7]))
# Save search
q_searches.append((header[6], header[7]))
# Forward to other nodes
forward(header, payload, socket)
elif header[2] == MSG_QHIT:
# Check if known message id
for (x, y) in q_searches:
if y == header[7]:
# Check if connection exists with given ip address
for (a, b) in connections:
if a == x:
data = bytearray()
data.extend(struct.pack('>HH', payload[0], 0))
for i in range(payload[0]):
data.extend(
struct.pack('>HH4s', i+1, 0,
binascii.unhexlify(
payload[1][i+1])))
b.send(createMessage(msg_type=MSG_QHIT,
org_port=header[4],
org_ip=header[6],
payload=data, msg_id=y))
# Forward messages to existing connections
def forward(header, payload, sock):
global connections
data = struct.pack('>'+str(len(payload[0]))+'s', payload[0])
message = createMessage(msg_type=MSG_QUERY, ttl=header[1]-1,
org_port=header[4], org_ip=header[6],
msg_id=header[7], payload=data)
for connection in connections:
# Don't send it back to searching node
if sock is not connection[1]:
print("Forwarded Message parsed:")
print(parseReceivedMessage(message))
connection[1].send(message)
def handshake(socket):
socket.send(createMessage(msg_type=MSG_JOIN,
org_ip=socket.getsockname()[0]))
response = socket.recv(1024)
header, payload = parseReceivedMessage(response)
# Join was successful
if payload == ('0200'):
global neighbours
neighbours.append((header[6], header[4]))
# Send PING type b to expand neighbourhood
socket.send(createMessage(ttl=5, org_port=socket.getsockname()[1],
org_ip=socket.getsockname()[0]))
response = socket.recv(1024)
header, payload = parseReceivedMessage(response)
if len(payload) > 0:
# Iterate through payload
for i in range(1, len(payload)):
# Add to neighbours if not already there
if not (payload[i][0], payload[i][1]) in neighbours:
neighbours.append((payload[i][0], payload[i][1]))
print("Neighbours:")
print(neighbours)
def p2p_replying(socket):
connected = True
while connected:
message = socket.recv(1024)
print("Message received:")
print(binascii.hexlify(message))
header, payload = parseReceivedMessage(message)
print(header)
print(payload)
# Disconnect after BYE
if(header[2] == MSG_BYE):
connected = False
process_message(header, payload, socket)
socket.close()
# Initialize connection before starting to reply
def p2p_initiation(socket):
handshake(socket)
p2p_replying(socket)
# Server sock listening on the given port.
def make_server_socket(port):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((socket.gethostname(), port))
print("Can be reached at "+socket.gethostbyname(socket.gethostname()) +
" port "+str(port))
s.listen(5)
return s
# Connect to existing network
def bootstrap(ip, port):
global connections
bootstrap = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
bootstrap.connect((ip, port))
connections.append((ip, bootstrap))
source = threading.Thread(target=p2p_initiation, args=[bootstrap])
source.start()
s = make_server_socket(6346)
try:
bootstrap(str(sys.argv[1]), int(sys.argv[2]))
except:
print("####################################################")
print("Node not connected to existing network. Use")
print("\'node.py <host-ip> <host-port>\' in order to do so.")
print("####################################################")
while 1:
(cl, address) = s.accept()
connections.append((address[0], cl))
print("accepted")
ct = threading.Thread(target=p2p_replying, args=[cl])
ct.start()