new_contents: #!/usr/bin/env python3
  #
  #  Copyright (c) 2021, The OpenThread Authors.
  #  All rights reserved.
  #
  #  Redistribution and use in source and binary forms, with or without
  #  modification, are permitted provided that the following conditions are met:
  #  1. Redistributions of source code must retain the above copyright
  #     notice, this list of conditions and the following disclaimer.
  #  2. Redistributions in binary form must reproduce the above copyright
  #     notice, this list of conditions and the following disclaimer in the
  #     documentation and/or other materials provided with the distribution.
  #  3. Neither the name of the copyright holder nor the
  #     names of its contributors may be used to endorse or promote products
  #     derived from this software without specific prior written permission.
  #
  #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  #  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  #  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  #  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  #  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  #  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  #  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  #  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  #  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  #  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  #  POSSIBILITY OF SUCH DAMAGE.
  #
  
  import sys
  import socket
  import binascii
  import syslog
  
  
  def main():
      interface = sys.argv[1]
      dst = sys.argv[2]
      port = sys.argv[3]
      payload = sys.argv[4]
  
      log = '====otbr-agent=send_udp===  send_udp.py started'
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
      log = 'dst %s' % dst
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
      log = 'interface %s' % interface
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
      log = 'port %s' % port
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
      log = 'payload %s' % payload
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
      byte_payload = binascii.unhexlify(payload)
  
      try:
          sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
          # Configure SO_BINDTODEVICE to bind the network interface.
          sock.setsockopt(socket.SOL_SOCKET, 25, interface.encode('utf-8'))
          sock.sendto(byte_payload, (dst, int(port)))
      except Exception as e:
          log = '====otbr-agent=send_udp=== sendto %s' % str(e)
          syslog.syslog(syslog.LOG_ERR, log)
          print(log)
  
      sock.close()
      log = '====otbr-agent=send_udp=== close'
      syslog.syslog(syslog.LOG_ERR, log)
      print(log)
  
  
  if __name__ == '__main__':
      main()
  
subject: add send_udp.py for certification (#840)