def awaiting_release_handler(circuit: NetRomCircuit, event: NetRomStateEvent,
netrom: NetRom,
logger: LoggingMixin) -> NetRomStateType:
assert circuit.state == NetRomStateType.AwaitingRelease
if event.event_type == NetRomEventType.NETROM_DISCONNECT_ACK:
if event.packet.circuit_idx == circuit.circuit_idx and event.packet.circuit_id == circuit.circuit_id:
netrom.nl_disconnect_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call)
return NetRomStateType.Disconnected
else:
logger.debug("Invalid disconnect ack. Disconnecting anyways")
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_DISCONNECT:
disc_ack = NetRomPacket(
event.packet.source,
event.packet.dest,
7, # TODO configure TTL
event.packet.circuit_idx,
event.packet.circuit_id,
0, # Our circuit idx
0, # Our circuit id
OpType.DisconnectAcknowledge.as_op_byte(False, False, False))
netrom.write_packet(disc_ack)
netrom.nl_disconnect_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call)
circuit.timer.cancel()
return NetRomStateType.Disconnected
else:
# TODO handle any other cases differently?
return NetRomStateType.AwaitingRelease
def awaiting_connection_handler(circuit: NetRomCircuit,
event: NetRomStateEvent, netrom: NetRom,
logger: LoggingMixin) -> NetRomStateType:
assert circuit.state == NetRomStateType.AwaitingConnection
if event.event_type == NetRomEventType.NETROM_CONNECT:
return NetRomStateType.AwaitingConnection
elif event.event_type == NetRomEventType.NETROM_CONNECT_ACK:
ack = cast(NetRomConnectAck, event.packet)
if ack.circuit_idx == circuit.circuit_idx and ack.circuit_id == circuit.circuit_id:
circuit.remote_circuit_idx = ack.tx_seq_num
circuit.remote_circuit_id = ack.rx_seq_num
circuit.window_size = ack.accept_window_size
netrom.nl_connect_indication(
circuit.circuit_idx, circuit.circuit_id, circuit.remote_call,
circuit.local_call, circuit.origin_node, circuit.origin_user)
circuit.timer.reset()
return NetRomStateType.Connected
else:
logger.debug("Unexpected circuit id in connection ack")
return NetRomStateType.AwaitingConnection
elif event.event_type in (NetRomEventType.NETROM_DISCONNECT,
NetRomEventType.NETROM_DISCONNECT_ACK,
NetRomEventType.NETROM_INFO,
NetRomEventType.NETROM_INFO_ACK):
return NetRomStateType.AwaitingConnection
elif event.event_type == NetRomEventType.NL_CONNECT:
conn = NetRomConnectRequest(
circuit.remote_call,
circuit.local_call,
7, # TODO configure TTL
circuit.circuit_idx,
circuit.circuit_id,
0, # Unused
0, # Unused
OpType.ConnectRequest.as_op_byte(False, False, False),
2, # TODO get this from config
circuit.origin_user, # Origin user
circuit.origin_node # Origin node
)
netrom.write_packet(conn)
circuit.timer.reset()
return NetRomStateType.AwaitingConnection
elif event.event_type in (NetRomEventType.NL_DISCONNECT,
NetRomEventType.NL_DATA):
return NetRomStateType.AwaitingConnection
def connected_handler(circuit: NetRomCircuit, event: NetRomStateEvent,
netrom: NetRom, logger: LoggingMixin) -> NetRomStateType:
assert circuit.state == NetRomStateType.Connected
if event.event_type == NetRomEventType.NETROM_CONNECT:
connect_req = cast(NetRomConnectRequest, event.packet)
if connect_req.circuit_idx == circuit.circuit_idx and connect_req.circuit_id == circuit.circuit_id:
# Treat this as a reconnect and ack it
connect_ack = NetRomConnectAck(
connect_req.source,
connect_req.dest,
7, # TODO get TTL from config
connect_req.circuit_idx,
connect_req.circuit_id,
circuit.circuit_idx,
circuit.circuit_id,
OpType.ConnectAcknowledge.as_op_byte(False, False, False),
connect_req.proposed_window_size)
netrom.write_packet(connect_ack)
netrom.nl_connect_indication(
circuit.circuit_idx, circuit.circuit_id, circuit.remote_call,
circuit.local_call, circuit.origin_node, circuit.origin_user)
circuit.timer.reset()
return NetRomStateType.Connected
else:
# Reject this and disconnect
logger.debug(
"Rejecting connect request due to invalid circuit ID/IDX")
connect_rej = NetRomConnectAck(
connect_req.source,
connect_req.dest,
7, # TODO get TTL from config
connect_req.circuit_idx,
connect_req.circuit_id,
circuit.circuit_idx,
circuit.circuit_id,
OpType.ConnectAcknowledge.as_op_byte(True, False, False),
connect_req.proposed_window_size)
netrom.write_packet(connect_rej)
netrom.nl_disconnect_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call)
circuit.timer.cancel()
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_CONNECT_ACK:
connect_ack = cast(NetRomConnectAck, event.packet)
if connect_ack.tx_seq_num == circuit.remote_circuit_idx and \
connect_ack.rx_seq_num == circuit.remote_circuit_id and \
connect_ack.circuit_idx == circuit.circuit_idx and \
connect_ack.circuit_id == circuit.circuit_id:
netrom.nl_connect_indication(
circuit.circuit_idx, circuit.circuit_id, circuit.remote_call,
circuit.local_call, circuit.origin_node, circuit.origin_user)
circuit.timer.reset()
return NetRomStateType.Connected
else:
# TODO what now?
return NetRomStateType.Connected
elif event.event_type == NetRomEventType.NETROM_DISCONNECT:
disc_ack = NetRomPacket(
event.packet.source,
event.packet.dest,
7, # TODO configure TTL
circuit.remote_circuit_id,
circuit.remote_circuit_id,
0, # Not used
0, # Not used
OpType.DisconnectAcknowledge.as_op_byte(False, False, False))
netrom.write_packet(disc_ack)
netrom.nl_disconnect_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call)
circuit.timer.cancel()
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_DISCONNECT_ACK:
logger.debug("Unexpected disconnect ack in connected state!")
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_INFO:
"""
The TX number from the INFO packet is the current sequence number while the the RX number is the next
expected sequence number on the other end of the circuit. This serves as a mechanism to acknowledge
previous INFO without sending an explicit ACK
"""
info = cast(NetRomInfo, event.packet)
if info.tx_seq_num == circuit.recv_state():
# We got the message number we expected
circuit.inc_recv_state()
circuit.enqueue_info_ack(netrom)
circuit.more += info.info
if not info.more_follows():
# TODO expire old more-follows data
netrom.nl_data_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call, circuit.more)
circuit.more = bytearray()
elif info.tx_seq_num < circuit.recv_state():
# Possible retransmission of previous message, ignore?
pass
else:
# Got a higher number than expected, we missed something, ask the sender to rewind
# to our last confirmed state
nak = NetRomPacket(
info.source,
info.dest,
7, # TODO config
circuit.remote_circuit_idx,
circuit.remote_circuit_id,
0, # Unused
circuit.recv_state(),
OpType.InformationAcknowledge.as_op_byte(False, True, False))
netrom.write_packet(nak)
# Handle the ack logic
if info.rx_seq_num > circuit.hw:
for seq in range(info.rx_seq_num, circuit.hw + 1):
seq = (seq + 127) % 128
circuit.info_futures[seq].set_result(True)
circuit.hw = info.rx_seq_num
else:
# Out of sync, error
pass
if info.rx_seq_num == circuit.send_state():
# We are in-sync, all is well
pass
elif info.rx_seq_num < circuit.send_state():
# Other side is lagging
pass
else:
# Other side has ack'd something out of range, raise an error
pass
# Handle the other flags
if info.choke():
# TODO stop sending until further notice
pass
if info.nak():
seq_resend = event.packet.rx_seq_num
logger.warning(f"Got Info NAK, rewinding to {seq_resend}")
while seq_resend < circuit.send_state():
info_to_resend = circuit.sent_info[seq_resend]
info_to_resend.rx_seq_num = circuit.recv_state()
netrom.write_packet(info_to_resend)
seq_resend += 1
return NetRomStateType.Connected
elif event.event_type == NetRomEventType.NETROM_INFO_ACK:
"""
If the choke flag is set (bit 7 of the opcode byte), it indicates that this node cannot accept any more
information messages until further notice. If the NAK flag is set (bit 6 of the opcode byte), it indicates that
a selective retransmission of the frame identified by the Rx Sequence Number is being requested.
"""
ack = event.packet
if ack.rx_seq_num > circuit.hw:
for seq in range(ack.rx_seq_num, circuit.hw + 1):
seq = (seq + 127) % 128
fut = circuit.info_futures.get(seq)
if fut:
fut.set_result(True)
circuit.hw = ack.rx_seq_num
else:
# Out of sync, error
pass
if ack.rx_seq_num == circuit.send_state():
seq = (ack.rx_seq_num + 127) % 128
fut = circuit.info_futures.get(seq)
if fut:
fut.set_result(True)
elif ack.rx_seq_num < circuit.send_state():
# Lagging behind
pass
else:
# Invalid state, error
pass
if ack.choke():
logger.warning("Got Info Choke")
# TODO stop sending until further notice
pass
if ack.nak():
seq_resend = event.packet.rx_seq_num
logger.warning(f"Got Info NAK, rewinding to {seq_resend}")
while seq_resend < circuit.send_state():
info_to_resend = circuit.sent_info[seq_resend]
info_to_resend.rx_seq_num = circuit.recv_state()
netrom.write_packet(info_to_resend)
seq_resend += 1
elif event.packet.rx_seq_num != circuit.send_state():
logger.warning("Info sync error")
# Out of sync, what now? Update circuit send state?
pass
return NetRomStateType.Connected
elif event.event_type == NetRomEventType.NL_CONNECT:
conn = NetRomConnectRequest(
circuit.remote_call,
circuit.local_call,
7, # TODO configure TTL
circuit.circuit_idx,
circuit.circuit_id,
0, # Unused
0, # Unused
OpType.ConnectRequest.as_op_byte(False, False, False),
2, # TODO get this from config
circuit.origin_user, # Origin user
circuit.origin_node, # Origin node
)
netrom.write_packet(conn)
circuit.timer.reset()
return NetRomStateType.AwaitingConnection
elif event.event_type == NetRomEventType.NL_DISCONNECT:
disc = NetRomPacket(
circuit.remote_call,
circuit.local_call,
7, # TODO configure TTL
circuit.remote_circuit_idx,
circuit.remote_circuit_id,
0,
0,
OpType.DisconnectRequest.as_op_byte(False, False, False))
netrom.write_packet(disc)
circuit.timer.cancel()
return NetRomStateType.AwaitingRelease
elif event.event_type == NetRomEventType.NL_DATA:
if event.mtu > 0:
fragments = list(chunks(event.data, event.mtu))
for fragment in fragments[:-1]:
info = NetRomInfo(
circuit.remote_call,
circuit.local_call,
7, # TODO
circuit.remote_circuit_idx,
circuit.remote_circuit_id,
circuit.send_state(),
circuit.recv_state(),
OpType.Information.as_op_byte(False, False, True),
fragment)
netrom.write_packet(info)
circuit.sent_info[info.tx_seq_num] = info
circuit.info_futures[info.tx_seq_num] = event.future
circuit.inc_send_state()
last = fragments[-1]
else:
last = event.data
info = NetRomInfo(
circuit.remote_call,
circuit.local_call,
7, # TODO
circuit.remote_circuit_idx,
circuit.remote_circuit_id,
circuit.send_state(),
circuit.recv_state(),
OpType.Information.as_op_byte(False, False, False),
last)
netrom.write_packet(info)
circuit.sent_info[info.tx_seq_num] = info
circuit.info_futures[info.tx_seq_num] = event.future
circuit.inc_send_state()
async def check_ack():
# TODO need to implement timeout and retry
await asyncio.sleep(10.000)
if circuit.hw <= info.tx_seq_num:
# Retransmit
print(f"Retransmit {info}")
#asyncio.create_task(check_ack())
return NetRomStateType.Connected
def disconnected_handler(circuit: NetRomCircuit, event: NetRomStateEvent,
netrom: NetRom,
logger: LoggingMixin) -> NetRomStateType:
assert circuit.state == NetRomStateType.Disconnected
if event.event_type == NetRomEventType.NETROM_CONNECT:
connect_req = cast(NetRomConnectRequest, event.packet)
connect_ack = NetRomConnectAck(
connect_req.source,
connect_req.dest,
7, # TODO get TTL from config
connect_req.circuit_idx,
connect_req.circuit_id,
circuit.circuit_idx,
circuit.circuit_id,
OpType.ConnectAcknowledge.as_op_byte(False, False, False),
connect_req.proposed_window_size)
circuit.remote_circuit_id = connect_req.circuit_id
circuit.remote_circuit_idx = connect_req.circuit_idx
if netrom.write_packet(connect_ack):
netrom.nl_connect_indication(
circuit.circuit_idx, circuit.circuit_id, circuit.remote_call,
circuit.local_call, circuit.origin_node, circuit.origin_user)
circuit.timer.reset()
return NetRomStateType.Connected
else:
return NetRomStateType.Disconnected
elif event.event_type in (NetRomEventType.NETROM_CONNECT_ACK,
NetRomEventType.NETROM_INFO,
NetRomEventType.NETROM_INFO_ACK):
# If we're disconnected, we don't have the remote circuit's ID/IDX, so we can't really do
# much here besides try to re-connect
logger.debug(
f"Got unexpected packet {event.packet}. Attempting to reconnect")
disc = NetRomPacket(
circuit.remote_call,
circuit.local_call,
7, # TODO configure TTL
circuit.remote_circuit_idx,
circuit.remote_circuit_id,
0,
0,
OpType.DisconnectRequest.as_op_byte(False, False, False))
if netrom.write_packet(disc):
return NetRomStateType.AwaitingRelease
else:
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_DISCONNECT_ACK:
# We are already disconnected, nothing to do here
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NETROM_DISCONNECT:
# Ack this even though we're not connected
disc_ack = NetRomPacket(
event.packet.source,
event.packet.dest,
7, # TODO configure TTL
0, # Don't know the remote circuit idx
0, # Don't know the remote circuit id
0, # Our circuit idx
0, # Our circuit id
OpType.DisconnectAcknowledge.as_op_byte(False, False, False))
netrom.write_packet(disc_ack)
netrom.nl_disconnect_indication(circuit.circuit_idx,
circuit.circuit_id,
circuit.remote_call,
circuit.local_call)
circuit.timer.cancel()
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NL_CONNECT:
conn = NetRomConnectRequest(
circuit.remote_call,
circuit.local_call,
7, # TODO configure TTL
circuit.circuit_idx,
circuit.circuit_id,
0, # Send no circuit idx
0, # Send no circuit id
OpType.ConnectRequest.as_op_byte(False, False, False),
2, # Proposed window size (TODO get this from config)
circuit.origin_user, # Origin user
circuit.origin_node, # Origin node
)
if netrom.write_packet(conn):
circuit.timer.start()
return NetRomStateType.AwaitingConnection
else:
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NL_DISCONNECT:
return NetRomStateType.Disconnected
elif event.event_type == NetRomEventType.NL_DATA:
logger.debug("Ignoring unexpected NL_DATA event in disconnected state")
return NetRomStateType.Disconnected
