[core] add the instance id (#9055)

It is difficult for testers to know whether the stack has been
automatically restarted in the background. This commit adds an
instance id to indicate whether the stack has been restarted.
The instance id is set to a random value when the OpenThread
instance is constructed and its value will not change after
initialization.

include/openthread/instance.h

@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (324)
+#define OPENTHREAD_API_VERSION (325)
 
 /**
  * @addtogroup api-instance
@@ -102,6 +102,17 @@ otInstance *otInstanceInit(void *aInstanceBuffer, size_t *aInstanceBufferSize);
  */
 otInstance *otInstanceInitSingle(void);
 
+/**
+ * Gets the instance identifier.
+ *
+ * The instance identifier is set to a random value when the instance is constructed, and then its value will not
+ * change after initialization.
+ *
+ * @returns The instance identifier.
+ *
+ */
+uint32_t otInstanceGetId(otInstance *aInstance);
+
 /**
  * This function indicates whether or not the instance is valid/initialized.
  *

src/cli/README.md

@@ -56,6 +56,7 @@ Done
 - [fem](#fem)
 - [history](README_HISTORY.md)
 - [ifconfig](#ifconfig)
+- [instanceid](#instanceid)
 - [ipaddr](#ipaddr)
 - [ipmaddr](#ipmaddr)
 - [joiner](README_JOINER.md)
@@ -1491,6 +1492,16 @@ Bring down the IPv6 interface.
 Done
 ```
 
+### instanceid
+
+Show OpenThread instance identifier.
+
+```bash
+> instanceid
+468697314
+Done
+```
+
 ### ipaddr
 
 List all IPv6 addresses assigned to the Thread interface.

src/cli/cli.cpp

@@ -4002,6 +4002,29 @@ exit:
     return error;
 }
 
+template <> otError Interpreter::Process<Cmd("instanceid")>(Arg aArgs[])
+{
+    otError error = OT_ERROR_INVALID_ARGS;
+
+    /**
+     * @cli instanceid
+     * @code
+     * instanceid
+     * 468697314
+     * Done
+     * @endcode
+     * @par api_copy
+     * #otInstanceGetId
+     */
+    if (aArgs[0].IsEmpty())
+    {
+        OutputLine("%lu", ToUlong(otInstanceGetId(GetInstancePtr())));
+        error = OT_ERROR_NONE;
+    }
+
+    return error;
+}
+
 const char *Interpreter::AddressOriginToString(uint8_t aOrigin)
 {
     static const char *const kOriginStrings[4] = {
@@ -8605,6 +8628,7 @@ otError Interpreter::ProcessCommand(Arg aArgs[])
         CmdEntry("history"),
 #endif
         CmdEntry("ifconfig"),
+        CmdEntry("instanceid"),
         CmdEntry("ipaddr"),
         CmdEntry("ipmaddr"),
 #if OPENTHREAD_CONFIG_JOINER_ENABLE

src/core/api/instance_api.cpp

@@ -70,6 +70,8 @@ otInstance *otInstanceInit(void *aInstanceBuffer, size_t *aInstanceBufferSize)
 otInstance *otInstanceInitSingle(void) { return &Instance::InitSingle(); }
 #endif // #if OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE
 
+uint32_t otInstanceGetId(otInstance *aInstance) { return AsCoreType(aInstance).GetId(); }
+
 bool otInstanceIsInitialized(otInstance *aInstance)
 {
 #if OPENTHREAD_MTD || OPENTHREAD_FTD

src/core/common/instance.cpp

@@ -245,6 +245,7 @@ Instance::Instance(void)
     , mPowerCalibration(*this)
 #endif
     , mIsInitialized(false)
+    , mId(Random::NonCrypto::GetUint32())
 {
 }
 

src/core/common/instance.hpp

@@ -207,6 +207,17 @@ public:
     static Instance &Get(void);
 #endif
 
+    /**
+     * Gets the instance identifier.
+     *
+     * The instance identifier is set to a random value when the instance is constructed, and then its value will not
+     * change after initialization.
+     *
+     * @returns The instance identifier.
+     *
+     */
+    uint32_t GetId(void) const { return mId; }
+
     /**
      * This method indicates whether or not the instance is valid/initialized and not yet finalized.
      *
@@ -645,6 +656,8 @@ private:
 #if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE && (OPENTHREAD_FTD || OPENTHREAD_MTD)
     static bool sDnsNameCompressionEnabled;
 #endif
+
+    uint32_t mId;
 };
 
 DefineCoreType(otInstance, Instance);

tests/scripts/expect/cli-misc.exp

@@ -86,6 +86,10 @@ send "ifconfig\n"
 expect "up"
 expect_line "Done"
 
+send "instanceid\n"
+expect -re {\d+}
+expect_line "Done"
+
 send "ipaddr add ::\n"
 expect_line "Done"
 send "ipaddr del ::\n"