def __delete_packet(self, pktid: str) -> None: """ Delete a packet received from the net :param pktid: id of the packet :return: None """ if LocalData.exist_in_received_packets(pktid): LocalData.delete_received_packet(pktid)
def serve(self, sd: socket.socket) -> None:
""" Handle a network packet
:param sd: the socket descriptor used for read the packet
:return: None
"""
try:
packet = sd.recv(200).decode()
except socket.error as e:
self.log.write_red(f'Unable to read the packet from the socket: {e}')
sd.close()
return
# log the packet received
socket_ip_sender = sd.getpeername()[0]
if ipaddress.IPv6Address(socket_ip_sender).ipv4_mapped is None:
socket_ip_sender = ipaddress.IPv6Address(socket_ip_sender).compressed
else:
socket_ip_sender = ipaddress.IPv6Address(socket_ip_sender).ipv4_mapped.compressed
socket_port_sender = sd.getpeername()[1]
self.log.write_green(f'{socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{packet}')
command = packet[:4]
if command == "SUPE":
sd.close()
if len(packet) != 82:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to reply.')
return
pktid = packet[4:20]
ip_peer = packet[20:75]
ip4_peer, ip6_peer = net_utils.get_ip_pair(ip_peer)
port_peer = int(packet[75:80])
ttl = packet[80:82]
# packet management
if pktid == LocalData.get_sent_supe_packet():
# if the SUPE i sent has been forwarded to me erroneously
return
if not LocalData.exist_in_received_packets(pktid):
LocalData.add_received_packet(pktid, ip_peer, port_peer)
t = Timer(20, function=self.__delete_packet, args=(pktid,))
t.start()
else:
return
# send the NEAR acknowledge
response = "ASUP" + pktid + net_utils.get_local_ip_for_response() +\
str(net_utils.get_network_port()).zfill(5)
try:
net_utils.send_packet_and_close(ip4_peer, ip6_peer, port_peer, response)
self.log.write_blue(f'Sending to {ip4_peer}|{ip6_peer} [{port_peer}] -> ', end='')
self.log.write(f'{response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending an {response} to {ip4_peer}|{ip6_peer} [{port_peer}]: {e}')
# forwarding the packet to other superpeers
self.__forward_packet(socket_ip_sender, ip_peer, ttl, packet)
elif command == "LOGI":
error_response = "ALGI" + '0' * 16
if len(packet) != 64:
self.log.write_red(f'Invalid packet received: {packet}')
try:
sd.send(error_response.encode())
sd.close()
self.log.write_blue(f'Sending to {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{error_response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending an ALGI response to {socket_ip_sender}: {e}')
return
return
ip = packet[4:59]
port = packet[59:64]
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
try:
sd.send(error_response.encode())
sd.close()
self.log.write_blue(f'Sending to {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{error_response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {error_response} to {socket_ip_sender}: {e}')
return
return
try:
peer = peer_repository.find_by_ip(conn, ip)
# if the peer didn't already logged in
if peer is None:
session_id = str(uuid.uuid4().hex[:16].upper())
peer = peer_repository.find(conn, session_id)
# while the generated session_id exists
while peer is not None:
session_id = str(uuid.uuid4().hex[:16].upper())
peer = peer_repository.find(conn, session_id)
peer = Peer(session_id, ip, port)
peer.insert(conn)
conn.commit()
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
try:
sd.send(error_response.encode())
sd.close()
self.log.write_blue(f'Sending to {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{error_response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {error_response} to {socket_ip_sender}: {e}')
return
return
response = "ALGI" + peer.session_id
try:
sd.send(response.encode())
sd.close()
self.log.write_blue(f'Sending to {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {response} to {socket_ip_sender}: {e}')
return
elif command == "ADFF":
sd.close()
if len(packet) != 152:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to add the file in the DB.')
return
session_id = packet[4:20]
md5 = packet[20:52]
name = packet[52:152].lower().lstrip().rstrip()
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
try:
peer = peer_repository.find(conn, session_id)
if peer is None:
conn.close()
self.log.write_red('Unauthorized request received: SessionID is invalid')
return
file = file_repository.find(conn, md5)
if file is None:
file = File(md5, name, 0)
file.insert(conn)
file_repository.add_owner(conn, md5, session_id)
else:
file.file_name = name
file.update(conn)
if not file_repository.peer_has_file(conn, session_id, md5):
file_repository.add_owner(conn, md5, session_id)
conn.commit()
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
self.log.write_blue(f'Successfully added file: {file.file_name} ({file.file_md5})')
elif command == "DEFF":
sd.close()
if len(packet) != 52:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to delete the file from the DB.')
return
session_id = packet[4:20]
md5 = packet[20:52]
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
try:
peer = peer_repository.find(conn, session_id)
if peer is None:
conn.close()
self.log.write_red('Unauthorized request received: SessionID is invalid')
return
if not file_repository.peer_has_file(conn, session_id, md5):
conn.close()
return
peer_repository.file_unlink(conn, session_id, md5)
copy = file_repository.get_copies(conn, md5)
if copy == 0:
file = file_repository.find(conn, md5)
file.delete(conn)
conn.commit()
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
self.log.write_blue(f'Successfully removed file: {file.file_name} ({file.file_md5})')
elif command == "FIND":
if len(packet) != 40:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to reply.')
sd.close()
return
session_id = packet[4:20]
query = packet[20:40].lower().lstrip().rstrip()
if query != '*':
query = '%' + query + '%'
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
sd.close()
return
# check in my peers files (DB)
try:
peer = peer_repository.find(conn, session_id)
if peer is None:
self.log.write_red('Unauthorized request received: SessionID is invalid')
sd.close()
return
else:
file_rows = file_repository.get_files_by_querystring(conn, query)
for file_row in file_rows:
file_md5 = file_row['file_md5']
file_name = file_row['file_name']
owner_rows = peer_repository.get_peers_by_file(conn, file_md5)
for owner_row in owner_rows:
owner_ip = owner_row['ip']
owner_port = owner_row['port']
LocalData.add_net_peer_file(owner_ip, owner_port, file_md5, file_name)
conn.commit()
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
sd.close()
return
# check in my shared files
for shared_file in LocalData.search_in_shared_files(query.strip('%')):
LocalData.add_net_peer_file(
net_utils.get_local_ip_for_response(),
net_utils.get_network_port(),
LocalData.get_shared_filemd5(shared_file),
LocalData.get_shared_filename(shared_file)
)
# flooding the QUER
pktid = str(uuid.uuid4().hex[:16].upper())
ip = net_utils.get_local_ip_for_response()
port = net_utils.get_aque_port()
ttl = '05'
query = packet[20:40]
packet = "QUER" + pktid + ip + str(port).zfill(5) + ttl + query
LocalData.set_sent_net_quer_packet(pktid)
server = ServerThread(port, NetworkTimedResponseHandler(self.log))
server.daemon = True
server.start()
timer = Timer(20, lambda: server.stop())
timer.start()
self.__broadcast_packet(packet)
timer.join()
try:
self.log.write_blue(f'Sending {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write('AFIN')
# send the AFIN packet
fragment = "AFIN" + str(LocalData.get_net_peer_files_md5_amount()).zfill(3)
sd.send(fragment.encode())
self.log.write_blue(f'Sending fragment -> ', end='')
self.log.write(f'{fragment}')
for md5 in LocalData.get_net_peer_files().keys():
fragment = md5 + LocalData.get_net_peer_file_name_by_md5(md5).ljust(100) + str(LocalData.get_net_peer_file_copy_amount_by_md5(md5)).zfill(3)
sd.send(fragment.encode())
self.log.write_blue(f'Sending fragment -> ', end='')
self.log.write(f'{fragment}')
for file_tuple in LocalData.get_net_peer_files_list_by_md5(md5):
fragment = LocalData.get_net_peer_file_owner_ip(file_tuple) + str(LocalData.get_net_peer_file_owner_port(file_tuple)).zfill(5)
sd.send(fragment.encode())
self.log.write_blue(f'Sending fragment -> ', end='')
self.log.write(f'{fragment}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending an AFIN response to {socket_ip_sender}: {e}')
sd.close()
LocalData.clear_net_peer_files()
elif command == "LOGO":
if len(packet) != 20:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to reply.')
sd.close()
return
session_id = packet[4:20]
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
sd.close()
return
try:
peer = peer_repository.find(conn, session_id)
if peer is None:
conn.close()
self.log.write_red('Unauthorized request received: SessionID is invalid')
sd.close()
return
deleted = file_repository.delete_peer_files(conn, session_id)
peer.delete(conn)
conn.commit()
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
sd.close()
return
response = "ALGO" + str(deleted).zfill(3)
try:
sd.send(response.encode())
sd.close()
self.log.write_blue(f'Sending {socket_ip_sender} [{socket_port_sender}] -> ', end='')
self.log.write(f'{response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {response} to {socket_ip_sender}: {e}')
return
elif command == "QUER":
sd.close()
if len(packet) != 102:
self.log.write_red(f'Invalid packet received: {packet}\nUnable to reply.')
return
self.log.write(f'{packet}')
pktid = packet[4:20]
ip_peer = packet[20:75]
ip4_peer, ip6_peer = net_utils.get_ip_pair(ip_peer)
port_peer = int(packet[75:80])
ttl = packet[80:82]
query = packet[82:102].lower().lstrip().rstrip()
if query != '*':
query = '%' + query + '%'
try:
conn = database.get_connection(self.db_file)
conn.row_factory = database.sqlite3.Row
except database.Error as e:
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
# check in my peers files (DB)
try:
total_file = file_repository.get_files_count_by_querystring(conn, query)
if total_file != 0:
file_rows = file_repository.get_files_by_querystring(conn, query)
for file_row in file_rows:
file_md5 = file_row['file_md5']
file_name = file_row['file_name']
owner_rows = peer_repository.get_peers_by_file(conn, file_md5)
for owner_row in owner_rows:
owner_ip = owner_row['ip']
owner_port = owner_row['port']
response = "AQUE" + pktid + owner_ip + owner_port + file_md5 + file_name.ljust(100)
try:
net_utils.send_packet_and_close(ip4_peer, ip6_peer, port_peer, response)
self.log.write_blue(f'Sending {ip4_peer}|{ip6_peer} [{port_peer}] -> ', end='')
self.log.write(f'{response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {response}: {e}')
conn.commit()
conn.close()
else:
conn.close()
except database.Error as e:
conn.rollback()
conn.close()
self.log.write_red(f'An error has occurred while trying to serve the request: {e}')
return
# check in my shared files
for local_shared_file in LocalData.search_in_shared_files(query.strip('%')):
local_ip = net_utils.get_local_ip_for_response()
local_port = str(net_utils.get_network_port()).zfill(5)
file_md5 = LocalData.get_shared_filemd5(local_shared_file)
file_name = LocalData.get_shared_filename(local_shared_file).ljust(100)
response = "AQUE" + pktid + local_ip + local_port + file_md5 + file_name
try:
net_utils.send_packet_and_close(ip4_peer, ip6_peer, port_peer, response)
self.log.write_blue(f'Sending {ip4_peer}|{ip6_peer} [{port_peer}] -> ', end='')
self.log.write(f'{response}')
except socket.error as e:
self.log.write_red(f'An error has occurred while sending {response}: {e}')
# forwarding the packet to other superpeers
self.__forward_packet(socket_ip_sender, ip_peer, ttl, packet)
elif command == "RETR":
if len(packet) != 36:
self.log.write_blue('Sending -> ', end='')
self.log.write('Invalid packet. Unable to reply.')
sd.send('Invalid packet. Unable to reply.'.encode())
sd.close()
return
file_md5 = packet[4:36]
file_name = LocalData.get_shared_filename_by_filemd5(file_md5)
if file_name is None:
self.log.write_blue('Sending -> ', end='')
self.log.write('Sorry, the requested file is not available anymore by the selected peer.')
sd.send('Sorry, the requested file is not available anymore by the selected peer.'.encode())
sd.close()
return
try:
f_obj = open('shared/' + file_name, 'rb')
except OSError as e:
self.log.write_red(f'Cannot open the file to upload: {e}')
self.log.write_blue('Sending -> ', end='')
self.log.write('Sorry, the peer encountered a problem while serving your packet.')
sd.send('Sorry, the peer encountered a problem while serving your packet.'.encode())
sd.close()
return
try:
Uploader(sd, f_obj, self.log).start()
self.log.write_blue(f'Sent {sd.getpeername()[0]} [{sd.getpeername()[1]}] -> ', end='')
self.log.write(f'{file_name}')
sd.close()
except OSError as e:
self.log.write_red(f'Error while sending the file: {e}')
sd.close()
return
else:
sd.close()
self.log.write_red(f'Invalid packet received from {socket_ip_sender} [{socket_port_sender}]: ', end='')
self.log.write(f'{packet}')
return