def establish(self):
header = Header()
self.isn = header.isn
self.seq_num = self.isn
header.syn = 1
send_packet(self.sender, header, logger=self.logger) # 1st handshake
received_header, received_data, dest_ip, dest_port, received_time = \
receive_packet(self.sender, self.logger)
if received_header.syn == 1 and received_header.ack == 1:
print('establishment request acked from {}:{}'.format(
dest_ip, dest_port))
header.syn = 0
header.ack = 1
self.ack_num = received_header.seq_num + 1
header.ack_num = self.ack_num
header.seq_num = received_header.ack_num
self.seq_num = header.seq_num
send_packet(self.sender, header,
logger=self.logger) # 3rd handshake
self.status = 2
return True
def close(self):
header = Header()
header.fin = 1
header.seq_num = self.seq_num
header.ack_num = self.ack_num
send_packet(self.sender, header, logger=self.logger)
print('connection to {}:{} closing'.format(self.dest_ip,
self.dest_port))
received_header, received_data, dest_ip, dest_port, received_time = \
receive_packet(self.sender, self.logger)
print(received_header.ack, received_header.ack_num, self.seq_num)
if received_header.ack == 1 and received_header.ack_num == self.seq_num + 1:
self.status = 3
received_header, received_msg, dest_ip, dest_port, received_time = \
receive_packet(self.sender, self.logger)
print('connection to {}:{} closed'.format(dest_ip, dest_port))
header = Header()
header.ack = 1
self.ack_num = received_header.seq_num + 1
header.ack_num = self.ack_num
send_packet(self.sender, header, logger=self.logger)
self.sender.close()
self.logger.sender_conclude()
def receive(self):
header = Header()
received_header, received_data, source_ip, source_port, received_time =\
receive_packet(self.receiver, logger=self.logger)
self.receiver.connect((source_ip, source_port))
if received_header.syn == 1 and received_header.ack == 0:
# 1st handshake
print('connection request from {}:{}'.format(
source_ip, source_port))
self.isn = header.isn
header.ack_num = received_header.seq_num + 1
self.ack_num = received_header.seq_num + 1
self.seq_num = header.seq_num
header.ack = 1
header.syn = 1
self.status = 1
send_packet(self.receiver, header,
logger=self.logger) # 2nd handshake
elif self.status == 1 and received_header.syn == 0 and received_header.ack == 1:
# 3rd handshake
self.seq_num = received_header.ack_num
self.data_bytes = b''
self.status = 2
print('connection established with {}:{}'.format(
source_ip, source_port))
elif self.status == 2 and received_header.fin == 1:
# closing
print('connection to {}:{} closing'.format(source_ip, source_port))
self.logger.data_size = len(self.data_bytes)
with open(FILE_RECEIVED, 'wb') as f:
f.write(self.data_bytes)
header.ack = 1
header.ack_num = received_header.seq_num + 1
self.ack_num = header.ack_num
header.seq_num = self.seq_num
send_packet(self.receiver, header, logger=self.logger)
header = Header()
header.fin = 1
header.seq_num = self.seq_num
header.ack_num = self.ack_num
send_packet(self.receiver, header, logger=self.logger)
# received_header, received_data, source_ip, source_port =\
# receive_packet(self.receiver)
print('connection to {}:{} closed'.format(source_ip, source_port))
self.logger.receiver_conclude()
return False
elif self.status == 2:
print('receiving data from {}:{}'.format(source_ip, source_port))
if len(received_data) > 0:
self.logger.num_segments += 1
if received_header.seq_num in self.buffer or received_header.seq_num < self.ack_num:
self.logger.dup_count += 1
if received_header.seq_num == self.ack_num:
self.ack_num = received_header.seq_num + len(received_data)
self.data_bytes += received_data
if len(self.buffer) > 0:
next_expected = received_header.seq_num + len(
received_data)
while next_expected in self.buffer:
buffered_next = self.buffer[next_expected]
self.data_bytes += buffered_next
next_expected += len(buffered_next)
self.ack_num += len(buffered_next)
elif received_header.seq_num > self.ack_num:
self.buffer[received_header.seq_num] = received_data
header = Header()
header.ack = 1
header.ack_num = self.ack_num
header.seq_num = self.seq_num
send_packet(self.receiver, header, logger=self.logger)
return True
def info_check(self):
header = Header()
#This should be added!
received_header, received_data, source_ip, source_port, received_time = receive_packet(self.receiver, logger=self.logger)
if not received_header:
return True
self.receiver.connect((source_ip, source_port))
if received_header.syn == 1 and received_header.ack == 0:
self.isn = header.isn
header.ack_num = received_header.seq_num+1
self.ack_num = received_header.seq_num+1
self.seq_num = header.seq_num
header.ack = 1
header.syn = 1
self.status = 1
send_packet(self.receiver, header, logger=self.logger)
#THis send_packet()
#judge_1 = self.status
#judge_2 = received_header.syn
#judge_3 = received_header.ack
elif self.status == 1 and received_header.syn ==2 and received_header.ack == 1:
self.seq_num = received_header.ack_num
self.data_num = b''
self.status = 2
elif self.status == 2 and received_header.fin == 1:
self.logger.data_size = len(self.data_num)
with open(file_name,'wb') as f:
f.write(self.data_num)
header.ack = 1
header.ack_num = received_header.seq_num+1
self.ack_num = header.ack_num
header.seq_num = self.seq_num
send_packet(self.receiver, header, logger = self.logger)
header = Header()
header.fin = 1
header.seq_num = self.seq_num
header.ack_num = self.ack_num
send_packet(self.receiver, header, logger = self.logger)
#Function
self.logger.receiver_conclude()
return False
elif self.status == 2:
if len(received_data) > 0:
self.logger.num_segments = self.logger.num_segments+1
if received_header.seq_num in self.memo or received_header.seq_num < self.ack_num:
self.logger.dup_count = self.logger.dup_count + 1
if len(self.memo) > 0:
check_next = received_header.seq_num+len(received_data)
while check_next in self.memo:
buffer_load = self.memo[check_next]
self.data_num = self.data_num + buffer_load
check_next = check_next + len(buffer_load)
self.ack_num = self.ack_num + len(buffer_load)
elif received_header.seq_num > self.ack_num:
print('Here is stage 3')
self.memo[received_header.seq_num] = received_data
print('here is the start of the header')
header = Header()
header.ack = 1
header.ack_num = self.ack_num
header.seq_num = self.seq_num
send_packet(self.receiver, header, logger = self.logger)
return True
