99 lines
3.3 KiB
Python
Executable File
99 lines
3.3 KiB
Python
Executable File
#!/usr/bin/env python
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############################################################################
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# tools/discover.py
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#
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# Copyright (C) 2012 Max Holtzberg. All rights reserved.
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# Author: Max Holtzberg <mh@uvc.de>
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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# 3. Neither the name NuttX nor the names of its contributors may be
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# used to endorse or promote products derived from this software
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# without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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############################################################################
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import array
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import time
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from socket import *
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PORT = 96
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DISCOVER_PROTO_ID = 0x99
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DISCOVER_ALL = 0xff # 0xff means all devices
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DISCOVER_REQUEST = 0x01
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DISCOVER_RESPONSE = 0x02
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DISCOVER_REQUEST_SIZE = 4
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DISCOVER_RESPONSE_SIZE = 35
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def check_sum(data):
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chksum = 0
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for c in data[:-1]:
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chksum -= c
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return (chksum & 0xff) == data[-1]
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def send_discover(socket):
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cmd = array.array('B', [0] * DISCOVER_REQUEST_SIZE)
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cmd[0] = DISCOVER_PROTO_ID # Tag for identification of the protocol
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cmd[1] = DISCOVER_REQUEST # Request command
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cmd[2] = DISCOVER_ALL
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chksum = 0
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for c in cmd[:3]:
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chksum -= c
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cmd[3] = chksum & 0xff
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socket.sendto(cmd, ('<broadcast>', PORT))
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def read_responses(socket):
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res = []
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response = array.array('B', [0] * DISCOVER_RESPONSE_SIZE)
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try:
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while 1:
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size, src = socket.recvfrom_into(response)
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if (size == DISCOVER_RESPONSE_SIZE
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and response[0] == DISCOVER_PROTO_ID
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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]
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dev['descr'] = response[2:-1].tostring().rstrip('\0')
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res.append(dev)
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except timeout:
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return res
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if __name__ == '__main__':
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print 'Sending discover...'
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s = socket(AF_INET, SOCK_DGRAM)
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s.bind(('0.0.0.0', PORT))
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s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
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s.settimeout(1.0)
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send_discover(s)
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devices = read_responses(s)
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socket.close(s)
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print devices
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