[tests] add traffic analysis for Cert_5_3_10 as TestPlan (#2502)

tests/scripts/thread-cert/node_cli.py

@@ -400,6 +400,21 @@ class otCli:
 
         return None
 
+    def get_eidcaches(self):
+        eidcaches = []
+        self.send_command('eidcache')
+
+        while True:
+            i = self.pexpect.expect(['([a-fA-F0-9\:]+) ([a-fA-F0-9]+)\r\n', 'Done'])
+            if i == 0:
+                eid = self.pexpect.match.groups()[0].decode("utf-8")
+                rloc = self.pexpect.match.groups()[1].decode("utf-8")
+                eidcaches.append((eid, rloc))
+            elif i == 1:
+                break
+
+        return eidcaches
+
     def add_service(self, enterpriseNumber, serviceData, serverData):
         cmd = 'service add ' + enterpriseNumber + ' ' + serviceData+ ' '  + serverData
         self.send_command(cmd)