circuitpython/tests/multi_espnow/30_lmk_echo.py

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esp32,esp8266: Add support for the Espressif ESP-NOW protocol. ESP-NOW is a proprietary wireless communication protocol which supports connectionless communication between ESP32 and ESP8266 devices, using vendor specific WiFi frames. This commit adds support for this protocol through a new `espnow` module. This commit builds on original work done by @nickzoic, @shawwwn and with contributions from @zoland. Features include: - Use of (extended) ring buffers in py/ringbuf.[ch] for robust IO. - Signal strength (RSSI) monitoring. - Core support in `_espnow` C module, extended by `espnow.py` module. - Asyncio support via `aioespnow.py` module (separate to this commit). - Docs provided at `docs/library/espnow.rst`. Methods available in espnow.ESPNow class are: - active(True/False) - config(): set rx buffer size, read timeout and tx rate - recv()/irecv()/recvinto() to read incoming messages from peers - send() to send messages to peer devices - any() to test if a message is ready to read - irq() to set callback for received messages - stats() returns transfer stats: (tx_pkts, tx_pkt_responses, tx_failures, rx_pkts, lost_rx_pkts) - add_peer(mac, ...) registers a peer before sending messages - get_peer(mac) returns peer info: (mac, lmk, channel, ifidx, encrypt) - mod_peer(mac, ...) changes peer info parameters - get_peers() returns all peer info tuples - peers_table supports RSSI signal monitoring for received messages: {peer1: [rssi, time_ms], peer2: [rssi, time_ms], ...} ESP8266 is a pared down version of the ESP32 ESPNow support due to code size restrictions and differences in the low-level API. See docs for details. Also included is a test suite in tests/multi_espnow. This tests basic espnow data transfer, multiple transfers, various message sizes, encrypted messages (pmk and lmk), and asyncio support. Initial work is from https://github.com/micropython/micropython/pull/4115. Initial import of code is from: https://github.com/nickzoic/micropython/tree/espnow-4115.
2020-09-24 01:37:04 -04:00
# Test of a ESPnow echo server and client transferring encrypted data.
# This test works with ESP32 or ESP8266 as server or client.
# First instance (echo server):
# Set the shared PMK
# Set the PEERS global to our mac addresses
# Run the echo server
# First exchange an unencrypted message from the client (so we
# can get its MAC address) and echo the message back (unenecrypted).
# Then set the peer LMK so all further communications are encrypted.
# Second instance (echo client):
# Set the shared PMK
# Send an unencrypted message to the server and wait for echo response.
# Set the LMK for the peer communications so all further comms are encrypted.
# Send random messages and compare with response from server.
try:
import network
import random
import time
import espnow
except ImportError:
print("SKIP")
raise SystemExit
# Set read timeout to 5 seconds
timeout_ms = 5000
default_pmk = b"MicroPyth0nRules"
default_lmk = b"0123456789abcdef"
sync = True
def echo_server(e):
peers = []
while True:
# Wait for messages from the client
peer, msg = e.recv(timeout_ms)
if peer is None:
return
if peer not in peers:
# If this is first message, add the peer unencrypted
e.add_peer(peer)
# Echo the message back to the sender
if not e.send(peer, msg, sync):
print("ERROR: send() failed to", peer)
return
if peer not in peers:
# If this is first message, add the peer encrypted
peers.append(peer)
e.del_peer(peer)
e.add_peer(peer, default_lmk)
if msg == b"!done":
return
# Send a message from the client and compare with response from server.
def echo_test(e, peer, msg, sync):
print("TEST: send/recv(msglen=", len(msg), ",sync=", sync, "): ", end="", sep="")
try:
if not e.send(peer, msg, sync):
print("ERROR: Send failed.")
return
except OSError as exc:
# Don't print exc as it is differs for esp32 and esp8266
print("ERROR: OSError:")
return
p2, msg2 = e.recv(timeout_ms)
if p2 is None:
print("ERROR: No response from server.")
raise SystemExit
print("OK" if msg2 == msg else "ERROR: Received != Sent")
# Send some random messages to server and check the responses
def echo_client(e, peer, msglens):
for sync in [True, False]:
for msglen in msglens:
msg = bytearray(msglen)
if msglen > 0:
msg[0] = b"_"[0] # Random message must not start with '!'
for i in range(1, msglen):
msg[i] = random.getrandbits(8)
echo_test(e, peer, msg, sync)
# Initialise the wifi and espnow hardware and software
def init(sta_active=True, ap_active=False):
wlans = [network.WLAN(i) for i in [network.STA_IF, network.AP_IF]]
e = espnow.ESPNow()
e.active(True)
e.set_pmk(default_pmk)
wlans[0].active(sta_active)
wlans[1].active(ap_active)
wlans[0].disconnect() # Force esp8266 STA interface to disconnect from AP
return e
# Server
def instance0():
e = init(True, False)
macs = [network.WLAN(i).config("mac") for i in (0, 1)]
print("Server Start")
multitest.globals(PEERS=macs)
multitest.next()
echo_server(e)
print("Server Done")
e.active(False)
# Client
def instance1():
e = init(True, False)
multitest.next()
peer = PEERS[0]
e.add_peer(peer)
echo_test(e, peer, b"start", True)
# Wait long enough for the server to set the lmk
time.sleep(0.1)
e.del_peer(peer)
e.add_peer(peer, default_lmk)
echo_client(e, peer, [250])
echo_test(e, peer, b"!done", True)
e.active(False)