nuttx/tools/discover.py

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#!/usr/bin/env python
############################################################################
# tools/discover.py
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership. The
# ASF licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the
# License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#
############################################################################
import array
import time
from socket import *
PORT = 96
DISCOVER_PROTO_ID = 0x99
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DISCOVER_ALL = 0xFF # 0xff means all devices
DISCOVER_REQUEST = 0x01
DISCOVER_RESPONSE = 0x02
DISCOVER_REQUEST_SIZE = 4
DISCOVER_RESPONSE_SIZE = 35
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def check_sum(data):
chksum = 0
for c in data[:-1]:
chksum -= c
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return (chksum & 0xFF) == data[-1]
def send_discover(socket):
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cmd = array.array("B", [0] * DISCOVER_REQUEST_SIZE)
cmd[0] = DISCOVER_PROTO_ID # Tag for identification of the protocol
cmd[1] = DISCOVER_REQUEST # Request command
cmd[2] = DISCOVER_ALL
chksum = 0
for c in cmd[:3]:
chksum -= c
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cmd[3] = chksum & 0xFF
socket.sendto(cmd, ("<broadcast>", PORT))
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def read_responses(socket):
res = []
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response = array.array("B", [0] * DISCOVER_RESPONSE_SIZE)
try:
while 1:
size, src = socket.recvfrom_into(response)
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if (
size == DISCOVER_RESPONSE_SIZE
and response[0] == DISCOVER_PROTO_ID
and response[1] == DISCOVER_RESPONSE
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and check_sum(response)
):
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dev = {}
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dev["addr"] = src[0]
dev["descr"] = response[2:-1].tostring().rstrip("\0")
res.append(dev)
except timeout:
return res
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if __name__ == "__main__":
print("Sending discover...")
s = socket(AF_INET, SOCK_DGRAM)
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s.bind(("0.0.0.0", PORT))
s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
s.settimeout(1.0)
send_discover(s)
devices = read_responses(s)
socket.close(s)
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print(devices)