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Fix timeout handling in DHCP lease renewal #169

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Merged
merged 2 commits into from
Jul 21, 2024
Merged

Fix timeout handling in DHCP lease renewal #169

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93087f3
Separate timeout fields from relative time for timeouts.
Jahor Jun 26, 2024
f66343a
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Jahor Jun 26, 2024
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42 changes: 26 additions & 16 deletions adafruit_wiznet5k/adafruit_wiznet5k_dhcp.py
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Original file line number Diff line number Diff line change
Expand Up @@ -26,10 +26,9 @@


import gc
import time
from random import randint
from micropython import const
from adafruit_ticks import ticks_ms, ticks_diff, ticks_add
from adafruit_ticks import ticks_ms, ticks_diff, ticks_add, ticks_less
from adafruit_wiznet5k.adafruit_wiznet5k_debug import ( # pylint: disable=ungrouped-imports
debug_msg,
)
Expand Down Expand Up @@ -152,7 +151,6 @@ def __init__(
# DHCP state machine
self._dhcp_state = _STATE_INIT
self._transaction_id = randint(1, 0x7FFFFFFF)
self._start_time = 0.0
self._start_ticks = 0
self._blocking = False
self._renew = None
Expand All @@ -165,9 +163,12 @@ def __init__(
self.dns_server_ip = _UNASSIGNED_IP_ADDR

# Lease expiry times
self._t1 = 0
self._t2 = 0
self._lease = 0
self._t1_timeout = 0
self._t2_timeout = 0
self._lease_timeout = 0
self._t1 = None
self._t2 = None
self._lease = None

# Host name
mac_string = "".join("{:02X}".format(o) for o in mac_address)
Expand Down Expand Up @@ -210,8 +211,10 @@ def _dsm_reset(self) -> None:
self.dns_server_ip = _UNASSIGNED_IP_ADDR
self._renew = None
self._increment_transaction_id()
self._start_time = time.monotonic()
self._start_ticks = ticks_ms()
self._lease = None
self._t1 = None
self._t2 = None

def _increment_transaction_id(self) -> None:
"""Increment the transaction ID and roll over from 0x7fffffff to 0."""
Expand Down Expand Up @@ -289,11 +292,14 @@ def _process_messaging_states(self, *, message_type: int):
self._dhcp_state = _STATE_INIT
elif message_type == _DHCP_ACK:
debug_msg("Message is ACK, setting FSM state to BOUND.", self._debug)
self._t1 = ticks_add(self._start_ticks, self._lease // 2)
self._t2 = ticks_diff(
ticks_add(self._start_ticks, self._lease), self._lease // 8
lease = self._lease or 60
self._lease_timeout = ticks_add(self._start_ticks, lease * 1000)
self._t1_timeout = ticks_add(
self._start_ticks, (self._t1 or (lease // 2)) * 1000
)
self._t2_timeout = ticks_add(
self._start_ticks, (self._t2 or (lease - lease // 8)) * 1000
)
self._lease = ticks_add(self._lease, self._start_ticks)
self._increment_transaction_id()
if not self._renew:
self._eth.ifconfig = (
Expand Down Expand Up @@ -391,16 +397,16 @@ def _dhcp_state_machine(self, *, blocking: bool = False) -> None:
while True:
if self._dhcp_state == _STATE_BOUND:
now = ticks_ms()
if ticks_diff(now, self._t1) < 0:
if ticks_less(now, self._t1_timeout):
debug_msg("No timers have expired. Exiting FSM.", self._debug)
return
if ticks_diff(now, self._lease) > 0:
if ticks_less(self._lease_timeout, now):
debug_msg(
"Lease has expired, switching state to INIT.", self._debug
)
self._blocking = True
self._dhcp_state = _STATE_INIT
elif ticks_diff(now, self._t2) > 0:
elif ticks_less(self._t2_timeout, now):
debug_msg(
"T2 has expired, switching state to REBINDING.", self._debug
)
Expand All @@ -414,16 +420,20 @@ def _dhcp_state_machine(self, *, blocking: bool = False) -> None:
if self._dhcp_state == _STATE_RENEWING:
debug_msg("FSM state is RENEWING.", self._debug)
self._renew = "renew"
self._start_time = time.monotonic()
self._start_ticks = ticks_ms()
self._lease = None
self._t1 = None
self._t2 = None
self._dhcp_state = _STATE_REQUESTING

if self._dhcp_state == _STATE_REBINDING:
debug_msg("FSM state is REBINDING.", self._debug)
self._renew = "rebind"
self.dhcp_server_ip = _BROADCAST_SERVER_ADDR
self._start_time = time.monotonic()
self._start_ticks = ticks_ms()
self._lease = None
self._t1 = None
self._t2 = None
self._dhcp_state = _STATE_REQUESTING

if self._dhcp_state == _STATE_INIT:
Expand Down
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