[border-router] centralize infra-if management in InfraIf (#12046)

This change moves the management of the infrastructure interface state
out of the `RoutingManager` and centralizes it within the `InfraIf`
class. This makes `InfraIf` a more self-contained component and
simplifies the logic in `RoutingManager`.

The `RoutingManager` now depends on an initialized `InfraIf`. Its
`Init()` method is simplified and is now called from
`InfraIf::Init()`.

The public API `otBorderRoutingInit()` now directly initializes the
`InfraIf`. The `InfraIf::Init()` method is updated to support
re-initialization, allowing to switch to a new interface. When
switching, it ensures that components on the previous interface are
stopped before restarting on the new one.

include/openthread/border_routing.h

@@ -211,19 +211,18 @@ typedef enum
 /**
  * Initializes the Border Routing Manager on given infrastructure interface.
  *
- * @note  This method MUST be called before any other otBorderRouting* APIs.
- * @note  This method can be re-called to change the infrastructure interface, but the Border Routing Manager should be
- *        disabled first, and re-enabled after.
+ * This function MUST be called before any other otBorderRouting* APIs.
+ *
+ * This function can also be used to re-initialize and switch the infrastructure interface index to a new one.
+ * Switching the interface index will trigger all components running on the previous interface (Border Routing,
+ * mDNS, etc) to be stopped (as if the previous if-index is no longer running) before restarting operations on the
+ * new interface.
  *
  * @param[in]  aInstance          A pointer to an OpenThread instance.
  * @param[in]  aInfraIfIndex      The infrastructure interface index.
  * @param[in]  aInfraIfIsRunning  A boolean that indicates whether the infrastructure
- *                                interface is running.
  *
  * @retval  OT_ERROR_NONE           Successfully started the Border Routing Manager on given infrastructure.
- * @retval  OT_ERROR_INVALID_STATE  The Border Routing Manager is in a state other than disabled or uninitialized.
- * @retval  OT_ERROR_INVALID_ARGS   The index of the infrastructure interface is not valid.
- * @retval  OT_ERROR_FAILED         Internal failure. Usually due to failure in generating random prefixes.
  *
  * @sa otPlatInfraIfStateChanged.
  * @sa otBorderRoutingSetEnabled.

include/openthread/instance.h

@@ -52,7 +52,7 @@ extern "C" {
  *
  * @note This number versions both OpenThread platform and user APIs.
  */
-#define OPENTHREAD_API_VERSION (544)
+#define OPENTHREAD_API_VERSION (545)
 
 /**
  * @addtogroup api-instance

src/core/api/border_routing_api.cpp

@@ -41,21 +41,28 @@ using namespace ot;
 
 otError otBorderRoutingInit(otInstance *aInstance, uint32_t aInfraIfIndex, bool aInfraIfIsRunning)
 {
-    return AsCoreType(aInstance).Get<BorderRouter::RoutingManager>().Init(aInfraIfIndex, aInfraIfIsRunning);
+    AsCoreType(aInstance).Get<BorderRouter::InfraIf>().Init(aInfraIfIndex, aInfraIfIsRunning);
+
+    return kErrorNone;
 }
 
 otError otBorderRoutingGetInfraIfInfo(otInstance *aInstance, uint32_t *aInfraIfIndex, bool *aInfraIfIsRunning)
 {
-    bool isRunning;
+    Error error = kErrorNone;
 
     AssertPointerIsNotNull(aInfraIfIndex);
 
-    if (aInfraIfIsRunning == nullptr)
+    VerifyOrExit(AsCoreType(aInstance).Get<BorderRouter::InfraIf>().IsInitialized(), error = kErrorInvalidState);
+
+    *aInfraIfIndex = AsCoreType(aInstance).Get<BorderRouter::InfraIf>().GetIfIndex();
+
+    if (aInfraIfIsRunning != nullptr)
     {
-        aInfraIfIsRunning = &isRunning;
+        *aInfraIfIsRunning = AsCoreType(aInstance).Get<BorderRouter::InfraIf>().IsRunning();
     }
 
-    return AsCoreType(aInstance).Get<BorderRouter::RoutingManager>().GetInfraIfInfo(*aInfraIfIndex, *aInfraIfIsRunning);
+exit:
+    return error;
 }
 
 otError otBorderRoutingSetEnabled(otInstance *aInstance, bool aEnabled)

src/core/border_router/infra_if.cpp

@@ -50,28 +50,45 @@ InfraIf::InfraIf(Instance &aInstance)
 {
 }
 
-Error InfraIf::Init(uint32_t aIfIndex)
+void InfraIf::Init(uint32_t aInfraIfIndex, bool aInfraIfIsRunning)
 {
-    Error error = kErrorNone;
+    if (mInitialized)
+    {
+        VerifyOrExit(aInfraIfIndex != mIfIndex);
 
-    VerifyOrExit(!mInitialized, error = kErrorInvalidState);
+        LogInfo("Switching previously configured %s to %lu", ToString().AsCString(), ToUlong(aInfraIfIndex));
 
-    mIfIndex     = aIfIndex;
+        // When switching interface index, we `Deinit()` to signal
+        // that the previous `mIfIndex` is down so that all modules
+        // operating on this interface are stopped before restarting
+        // operation on the new interface.
+
+        Deinit();
+    }
+
+    mIfIndex     = aInfraIfIndex;
     mInitialized = true;
 
     LogInfo("Init %s", ToString().AsCString());
 
+    Get<RoutingManager>().Init();
+
 exit:
-    return error;
+    IgnoreError(HandleStateChanged(mIfIndex, aInfraIfIsRunning));
 }
 
 void InfraIf::Deinit(void)
 {
-    mInitialized = false;
-    mIsRunning   = false;
-    mIfIndex     = 0;
+    VerifyOrExit(mInitialized);
 
-    LogInfo("Deinit");
+    LogInfo("Deinit %s", ToString().AsCString());
+
+    IgnoreError(HandleStateChanged(mIfIndex, /* aIsRunning */ false));
+
+    mInitialized = false;
+
+exit:
+    return;
 }
 
 bool InfraIf::HasAddress(const Ip6::Address &aAddress) const

src/core/border_router/infra_if.hpp

@@ -101,13 +101,15 @@ public:
     /**
      * Initializes the `InfraIf`.
      *
-     * @param[in]  aIfIndex        The infrastructure interface index.
+     * This method can also be used to re-initialize and switch the infrastructure interface index to a new one.
+     * Switching the interface index will trigger all components running on the previous interface (Border Routing,
+     * mDNS, etc) to be stopped (as if the previous if-index is no longer running) before restarting operations on the
+     * new interface.
      *
-     * @retval  kErrorNone         Successfully initialized the `InfraIf`.
-     * @retval  kErrorInvalidArgs  The index of the infra interface is not valid.
-     * @retval  kErrorInvalidState The `InfraIf` is already initialized.
+     * @param[in]  aInfraIfIndex      The infrastructure network interface index.
+     * @param[in]  aInfraIfIsRunning  A boolean that indicates whether the infrastructure interface is running.
      */
-    Error Init(uint32_t aIfIndex);
+    void Init(uint32_t aInfraIfIndex, bool aInfraIfIsRunning);
 
     /**
      * Deinitilaizes the `InfraIf`.

src/core/border_router/routing_manager.cpp

@@ -73,65 +73,26 @@ RoutingManager::RoutingManager(Instance &aInstance)
     mBrUlaPrefix.Clear();
 }
 
-Error RoutingManager::Init(uint32_t aInfraIfIndex, bool aInfraIfIsRunning)
+void RoutingManager::Init(void)
 {
-    Error error;
+    VerifyOrExit(Get<InfraIf>().IsInitialized());
 
-    VerifyOrExit(GetState() == kStateUninitialized || GetState() == kStateDisabled, error = kErrorInvalidState);
-
-    if (!Get<InfraIf>().IsInitialized())
-    {
-        LogInfo("Initializing - InfraIfIndex:%lu", ToUlong(aInfraIfIndex));
-        SuccessOrExit(error = Get<InfraIf>().Init(aInfraIfIndex));
-        SuccessOrExit(error = LoadOrGenerateRandomBrUlaPrefix());
-        mOmrPrefixManager.Init(mBrUlaPrefix);
+    LoadOrGenerateRandomBrUlaPrefix();
+    mOmrPrefixManager.Init(mBrUlaPrefix);
 #if OPENTHREAD_CONFIG_NAT64_BORDER_ROUTING_ENABLE
-        mNat64PrefixManager.GenerateLocalPrefix(mBrUlaPrefix);
+    mNat64PrefixManager.GenerateLocalPrefix(mBrUlaPrefix);
 #endif
-        mOnLinkPrefixManager.Init();
-    }
-    else if (aInfraIfIndex != Get<InfraIf>().GetIfIndex())
-    {
-        LogInfo("Reinitializing - InfraIfIndex:%lu -> %lu", ToUlong(Get<InfraIf>().GetIfIndex()),
-                ToUlong(aInfraIfIndex));
-
-#if OPENTHREAD_CONFIG_MULTICAST_DNS_ENABLE && OPENTHREAD_CONFIG_MULTICAST_DNS_AUTO_ENABLE_ON_INFRA_IF
-        IgnoreError(Get<Dns::Multicast::Core>().SetEnabled(false, Get<InfraIf>().GetIfIndex()));
-#endif
-
-        Get<InfraIf>().SetIfIndex(aInfraIfIndex);
-    }
-
-    error = Get<InfraIf>().HandleStateChanged(Get<InfraIf>().GetIfIndex(), aInfraIfIsRunning);
+    mOnLinkPrefixManager.Init();
 
 exit:
-    if (error != kErrorNone)
-    {
-        Get<InfraIf>().Deinit();
-    }
-
-    return error;
-}
-
-bool RoutingManager::IsInitialized(void) const { return Get<InfraIf>().IsInitialized(); }
-
-Error RoutingManager::GetInfraIfInfo(uint32_t &aInfraIfIndex, bool &aInfraIfIsRunning) const
-{
-    Error error = kErrorNone;
-
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
-    aInfraIfIndex     = Get<InfraIf>().GetIfIndex();
-    aInfraIfIsRunning = Get<InfraIf>().IsRunning();
-
-exit:
-    return error;
+    return;
 }
 
 Error RoutingManager::SetEnabled(bool aEnabled)
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
 
     VerifyOrExit(aEnabled != mIsEnabled);
 
@@ -147,7 +108,7 @@ RoutingManager::State RoutingManager::GetState(void) const
 {
     State state = kStateUninitialized;
 
-    VerifyOrExit(IsInitialized());
+    VerifyOrExit(Get<InfraIf>().IsInitialized());
     VerifyOrExit(IsEnabled(), state = kStateDisabled);
 
     state = IsRunning() ? kStateRunning : kStateStopped;
@@ -160,7 +121,7 @@ Error RoutingManager::GetOmrPrefix(Ip6::Prefix &aPrefix) const
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     aPrefix = mOmrPrefixManager.GetGeneratedPrefix();
 
 exit:
@@ -172,7 +133,7 @@ Error RoutingManager::GetDhcp6PdOmrPrefix(Dhcp6PdPrefix &aPrefix) const
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     error = mPdPrefixManager.GetPrefix(aPrefix);
 
 exit:
@@ -183,7 +144,7 @@ Error RoutingManager::GetDhcp6PdCounters(Dhcp6PdCounters &aCounters)
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     error = mPdPrefixManager.GetCounters(aCounters);
 
 exit:
@@ -207,7 +168,7 @@ Error RoutingManager::GetOnLinkPrefix(Ip6::Prefix &aPrefix) const
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     aPrefix = mOnLinkPrefixManager.GetLocalPrefix();
 
 exit:
@@ -218,7 +179,7 @@ Error RoutingManager::GetFavoredOnLinkPrefix(Ip6::Prefix &aPrefix) const
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     aPrefix = mOnLinkPrefixManager.GetFavoredPrefix();
 
 exit:
@@ -236,7 +197,7 @@ Error RoutingManager::GetNat64Prefix(Ip6::Prefix &aPrefix)
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     aPrefix = mNat64PrefixManager.GetLocalPrefix();
 
 exit:
@@ -247,7 +208,7 @@ Error RoutingManager::GetFavoredNat64Prefix(Ip6::Prefix &aPrefix, RoutePreferenc
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(IsInitialized(), error = kErrorInvalidState);
+    VerifyOrExit(Get<InfraIf>().IsInitialized(), error = kErrorInvalidState);
     aPrefix = mNat64PrefixManager.GetFavoredPrefix(aRoutePreference);
 
 exit:
@@ -255,10 +216,9 @@ exit:
 }
 #endif
 
-Error RoutingManager::LoadOrGenerateRandomBrUlaPrefix(void)
+void RoutingManager::LoadOrGenerateRandomBrUlaPrefix(void)
 {
-    Error error     = kErrorNone;
-    bool  generated = false;
+    bool generated = false;
 
     if (Get<Settings>().Read<Settings::BrUlaPrefix>(mBrUlaPrefix) != kErrorNone || !IsValidBrUlaPrefix(mBrUlaPrefix))
     {
@@ -266,7 +226,7 @@ Error RoutingManager::LoadOrGenerateRandomBrUlaPrefix(void)
 
         LogNote("No valid /48 BR ULA prefix found in settings, generating new one");
 
-        SuccessOrExit(error = randomUlaPrefix.GenerateRandomUla());
+        SuccessOrAssert(randomUlaPrefix.GenerateRandomUla());
 
         mBrUlaPrefix.Set(randomUlaPrefix);
         mBrUlaPrefix.SetSubnetId(0);
@@ -279,13 +239,6 @@ Error RoutingManager::LoadOrGenerateRandomBrUlaPrefix(void)
     OT_UNUSED_VARIABLE(generated);
 
     LogNote("BR ULA prefix: %s (%s)", mBrUlaPrefix.ToString().AsCString(), generated ? "generated" : "loaded");
-
-exit:
-    if (error != kErrorNone)
-    {
-        LogCrit("Failed to generate random /48 BR ULA prefix");
-    }
-    return error;
 }
 
 void RoutingManager::EvaluateState(void)
@@ -435,7 +388,7 @@ void RoutingManager::HandleNotifierEvents(Events aEvents)
 
     mRoutePublisher.HandleNotifierEvents(aEvents);
 
-    VerifyOrExit(IsInitialized() && IsEnabled());
+    VerifyOrExit(Get<InfraIf>().IsInitialized() && IsEnabled());
 
     if (aEvents.Contains(kEventThreadRoleChanged))
     {

src/core/border_router/routing_manager.hpp

@@ -156,27 +156,9 @@ public:
     explicit RoutingManager(Instance &aInstance);
 
     /**
-     * Initializes the routing manager on given infrastructure interface.
-     *
-     * @param[in]  aInfraIfIndex      An infrastructure network interface index.
-     * @param[in]  aInfraIfIsRunning  A boolean that indicates whether the infrastructure
-     *                                interface is running.
-     *
-     * @retval  kErrorNone         Successfully started the routing manager.
-     * @retval  kErrorInvalidArgs  The index of the infra interface is not valid.
+     * Initializes the routing manager.
      */
-    Error Init(uint32_t aInfraIfIndex, bool aInfraIfIsRunning);
-
-    /**
-     * Gets the interface index of the currently configured infrastructure interface.
-     *
-     * @param[out] aInfraIfIndex      A reference to output the interface index.
-     * @param[out] aInfraIfIsRunning  A reference to output whether the interface is running.
-     *
-     * @retval kErrorNone           Successfully retrieved the interface information.
-     * @retval kErrorInvalidState   The Border Routing Manager is not initialized.
-     */
-    Error GetInfraIfInfo(uint32_t &aInfraIfIndex, bool &aInfraIfIsRunning) const;
+    void Init(void);
 
     /**
      * Enables/disables the Border Routing Manager.
@@ -1103,13 +1085,12 @@ private:
     //------------------------------------------------------------------------------------------------------------------
     // Methods
 
-    void  EvaluateState(void);
-    void  Start(void);
-    void  Stop(void);
-    void  HandleNotifierEvents(Events aEvents);
-    bool  IsInitialized(void) const;
-    bool  IsEnabled(void) const { return mIsEnabled; }
-    Error LoadOrGenerateRandomBrUlaPrefix(void);
+    void EvaluateState(void);
+    void Start(void);
+    void Stop(void);
+    void HandleNotifierEvents(Events aEvents);
+    bool IsEnabled(void) const { return mIsEnabled; }
+    void LoadOrGenerateRandomBrUlaPrefix(void);
 
     void EvaluateRoutingPolicy(void);
     bool IsInitialPolicyEvaluationDone(void) const;

tests/fuzz/cli.cpp

@@ -111,7 +111,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     otCliInit(&node.GetInstance(), CliOutput, nullptr);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);

tests/fuzz/icmp6.cpp

@@ -100,7 +100,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     node.GetInstance().SetLogLevel(kLogLevelInfo);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);

tests/fuzz/ip6.cpp

@@ -112,7 +112,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     node.GetInstance().SetLogLevel(kLogLevelInfo);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);

tests/fuzz/mdns.cpp

@@ -111,7 +111,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     node.GetInstance().SetLogLevel(kLogLevelInfo);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);

tests/fuzz/radio-one-node.cpp

@@ -110,7 +110,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     node.GetInstance().SetLogLevel(kLogLevelInfo);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);

tests/fuzz/trel.cpp

@@ -101,7 +101,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
 
     node.GetInstance().SetLogLevel(kLogLevelInfo);
 
-    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::InfraIf>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
     node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
     node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);