[thci] move zeroconf execution to the commissioner device (#7419)

So far zeroconf was running on the Windows Harness server and there
was no control on which Ethernet interface to scan.

tests/scripts/thread-cert/find_border_agents.py

@@ -0,0 +1,98 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2022, 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 ipaddress
+import sys
+import time
+from zeroconf import ServiceBrowser, ServiceStateChange, Zeroconf, DNSAddress, DNSService, DNSText
+
+
+def on_service_state_change(zeroconf, service_type, name, state_change):
+    if state_change is ServiceStateChange.Added:
+        zeroconf.get_service_info(service_type, name)
+
+
+class BorderAgent(object):
+    alias = None
+    server_name = None
+    link_local_addr = None
+    port = None
+    thread_status = None
+
+    def __init__(self, alias):
+        self.alias = alias
+
+    def __repr__(self):
+        return str([self.alias, self.link_local_addr, self.port, self.thread_status])
+
+
+def parse_cache(cache):
+    border_agents = []
+
+    # Find all border routers
+    for ptr in cache['_meshcop._udp.local.']:
+        border_agents.append(BorderAgent(ptr.alias))
+
+    # Find server name, port and Thread Interface status for each border router
+    for ba in border_agents:
+        for record in cache[ba.alias.lower()]:
+            if isinstance(record, DNSService):
+                ba.server_name = record.server
+                ba.port = record.port
+            elif isinstance(record, DNSText):
+                text = bytearray(record.text)
+                sb = text.split(b'sb=')[1][0:4]
+                ba.thread_status = (sb[3] & 0x18) >> 3
+
+    # Find link local address for each border router
+    for ba in border_agents:
+        for record in cache[ba.server_name.lower()]:
+            if isinstance(record, DNSAddress):
+                addr = ipaddress.ip_address(record.address)
+                if isinstance(addr, ipaddress.IPv6Address) and addr.is_link_local:
+                    ba.link_local_addr = str(addr)
+                    break
+
+    return border_agents
+
+
+def main():
+    # Browse border agents
+    zeroconf = Zeroconf()
+    ServiceBrowser(zeroconf, "_meshcop._udp.local.", handlers=[on_service_state_change])
+    time.sleep(2)
+    cache = zeroconf.cache.cache
+    zeroconf.close()
+
+    border_agents = parse_cache(cache)
+    for ba in border_agents:
+        print(ba)
+
+
+if __name__ == '__main__':
+    main()