def send(self, msg):
floor = 0
payload_size = 512
packets = []
# chunk data into packets
while floor < len(msg):
if floor + payload_size <= len(msg):
payload = msg[floor: floor + payload_size]
else:
payload = msg[floor:]
data_packet = RxPPacket(
self.port_number,
self.destination[1],
seq_number=self.seq_number,
payload=payload
)
packets.append(data_packet)
self.seq_number += 1
floor += payload_size
kill_packet = RxPPacket(
self.port_number,
self.destination[1],
seq_number=self.seq_number
)
kills_sent = 0 # allow to be sent 3 times before dropping client cxn
kill_seq_number = kill_packet.seq_number
packets.append(kill_packet) # put that shit at the end after we've added all the other packets
self.seq_number += 1
self.logger.debug('Placing packets in window to be sent now...')
window = SlidingWindow(packets, self.window_size)
time_sent = time.time()
time_remaining = self.retransmit_timer.timeout
self.cxn_status = RxPConnectionStatus.SEND
for data_packet in window.window:
self.io.send_queue.put((data_packet, self.destination))
while not window.is_empty():
try:
ack_packet, address = self.io.recv_queue.get(True, time_remaining)
# resend entire send window (all packets that weren't yet ACK'd by the receiver)
except Queue.Empty:
self.logger.debug(
'Timed out waiting for ack during data transmission; retransmitting unacknowledged packets.')
time_sent = time.time()
time_remaining = self.retransmit_timer.timeout
for data_packet in window.window:
if kill_seq_number == data_packet.seq_number:
kills_sent += 1
if kills_sent > 3: # if retransmitted 3 times already, kill cxn with client
self.logger.debug(
'Kill packet failed to be acknowledged; unable to end connection, closing now.')
return
if not window.acknowledged_packets.get(data_packet.seq_number):
data_packet.frequency += 1
data_packet.update_checksum()
self.io.send_queue.put((data_packet, self.destination))
continue
# if still getting SYN/ACK, retransmit ACK
if self.__verify_syn_ack(ack_packet, address, 1):
self.logger.debug('Received SYN/ACK retransmission; retransmitting ACK.')
ack_packet = RxPPacket(
self.port_number,
self.destination[1],
ack_number=ack_packet.seq_number + 1,
seq_number=2,
ack=True
)
self.io.send_queue.put((ack_packet, self.destination))
time_remaining = 0
# if a packet in window is acknowledged, slide the window past said received packet
elif self.__verify_is_ack(ack_packet, address) and window.index_of_packet(ack_packet) >= 0:
self.retransmit_timer.update(ack_packet.frequency, time.time() - time_sent)
self.logger.debug(
'ACK received. Updated retransmit timer; timeout is now ' + str(self.retransmit_timer.timeout))
window.acknowledge_packet(ack_packet)
if self.__verify_ack(ack_packet, address, window.window[0].seq_number):
additions = window.slide()
# send newly added packets if they were added
if additions > 0:
while additions > 0:
self.io.send_queue.put((window.window[-additions], self.destination))
self.seq_number += 1
additions -= 1
# otherwise, update time remaining
else:
time_remaining -= time.time() - time_sent / 4 # decay
if time_remaining < time.time():
time_remaining = .5
self.logger.debug('Trash packet receive; time remaining before next timeout: ' + str(time_remaining))
self.cxn_status = RxPConnectionStatus.IDLE
def mf_write(self, data):
start = 0
payload_size = 512
packets = []
# chunk data into packets
while start < len(data):
if start + payload_size <= len(data):
payload = data[start : start + payload_size]
else:
payload = data[start :]
data_packet = MFPacket(
self.port_number,
self.destination[1],
sequence_number = self.sequence_number,
payload = payload
)
packets.append(data_packet)
self.sequence_number += 1
start += payload_size
terminator_packet = MFPacket(
self.port_number,
self.destination[1],
sequence_number = self.sequence_number
)
packets.append(terminator_packet)
self.terminator_packet_seq_num = self.sequence_number
self.terminator_packet_num_sent = 0
self.sequence_number += 1
# populate window and send all packets
window = SlidingWindow(packets, self.window_size)
last_sent = time.time()
time_remaining = self.retransmit_timer.timeout
self.logger.debug('sending data packets in window.')
for data_packet in window.window:
self.io_loop.send_queue.put((data_packet, self.destination))
#print data_packet.data_offset
while not window.is_empty():
try:
# wait for incoming packet
ack_packet, address = self.io_loop.receive_queue.get(True, time_remaining)
except Queue.Empty:
# timeout, go back n
self.logger.debug('timed out waiting for ack during data transmission. retransmitting window.')
last_sent = time.time()
time_remaining = self.retransmit_timer.timeout
for data_packet in window.window:
if self.terminator_packet_seq_num == data_packet.sequence_number:
self.terminator_packet_num_sent += 1
if self.terminator_packet_num_sent > 3:
self.logger.debug('Unable to end connection, terminating now')
return
data_packet.frequency += 1
data_packet.recalculate_checksum()
self.io_loop.send_queue.put((data_packet, self.destination))
continue
# if still getting syn/ack, retransmit ack
if self.__verify_syn_ack(ack_packet, address, 1):
self.logger.debug('received syn/ack retransmission. retransmitting ack.')
ack_packet = MFPacket(
self.port_number,
self.destination[1],
ack_number = ack_packet.sequence_number + 1,
sequence_number = 2,
ack = True
)
self.io_loop.send_queue.put((ack_packet, self.destination))
time_remaining = 0
# if first packet in pipeline is acknowledged, slide the window
elif self.__verify_ack(ack_packet, address, window.window[0].sequence_number):
self.retransmit_timer.update(ack_packet.frequency, time.time() - last_sent)
self.logger.debug('updated retransmit timer. timeout is now ' + str(self.retransmit_timer.timeout))
window.slide()
if not window.is_emptying():
self.io_loop.send_queue.put((window.window[-1], self.destination))
self.sequence_number += 1
#print "executing"
# otherwise, update time remaining
else:
time_remaining -= time.time() - last_sent/4
if time_remaining < time.time():
time_remaining = .5
self.logger.debug('bunk packet received. time remaining before timeout: ' + str(time_remaining))