[ESP32] Support Thread and Wi-Fi network revert configuration (#33745)

* ESP32: Support Thread and Wi-Fi network revert configuration

* Update src/platform/ESP32/NetworkCommissioningDriver.cpp

Co-authored-by: Wang Qixiang <43193572+wqx6@users.noreply.github.com>

* Update KeyValueStoreManagerImpl.cpp

---------

Co-authored-by: Wang Qixiang <43193572+wqx6@users.noreply.github.com>

src/platform/ESP32/KeyValueStoreManagerImpl.cpp

@@ -68,7 +68,7 @@ KeyValueStoreManagerImpl KeyValueStoreManagerImpl::sInstance;
 CHIP_ERROR KeyValueStoreManagerImpl::_Get(const char * key, void * value, size_t value_size, size_t * read_bytes_size,
                                           size_t offset_bytes)
 {
-    VerifyOrReturnError(value, CHIP_ERROR_INVALID_ARGUMENT);
+    // value may be NULL when checking whether the key exists
 
     // Offset and partial reads are not supported in nvs, for now just return NOT_IMPLEMENTED. Support can be added in the
     // future if this is needed.

src/platform/ESP32/NetworkCommissioningDriver.cpp

@@ -95,39 +95,31 @@ CHIP_ERROR GetConfiguredNetwork(Network & network)
 
 CHIP_ERROR ESPWiFiDriver::Init(NetworkStatusChangeCallback * networkStatusChangeCallback)
 {
-    CHIP_ERROR err;
-    size_t ssidLen        = 0;
-    size_t credentialsLen = 0;
-
-    err = PersistedStorage::KeyValueStoreMgr().Get(kWiFiCredentialsKeyName, mSavedNetwork.credentials,
-                                                   sizeof(mSavedNetwork.credentials), &credentialsLen);
-    if (err == CHIP_ERROR_NOT_FOUND)
+    wifi_config_t stationConfig;
+    if (esp_wifi_get_config(WIFI_IF_STA, &stationConfig) == ESP_OK && stationConfig.sta.ssid[0] != 0)
     {
-        return CHIP_NO_ERROR;
-    }
+        uint8_t ssidLen = static_cast<uint8_t>(
+            strnlen(reinterpret_cast<const char *>(stationConfig.sta.ssid), DeviceLayer::Internal::kMaxWiFiSSIDLength));
+        memcpy(mStagingNetwork.ssid, stationConfig.sta.ssid, ssidLen);
+        mStagingNetwork.ssidLen = ssidLen;
 
-    err = PersistedStorage::KeyValueStoreMgr().Get(kWiFiSSIDKeyName, mSavedNetwork.ssid, sizeof(mSavedNetwork.ssid), &ssidLen);
-    if (err == CHIP_ERROR_NOT_FOUND)
-    {
-        return CHIP_NO_ERROR;
-    }
-    if (!CanCastTo<uint8_t>(credentialsLen))
-    {
-        return CHIP_ERROR_INCORRECT_STATE;
-    }
-    mSavedNetwork.credentialsLen = static_cast<uint8_t>(credentialsLen);
+        uint8_t credentialsLen = static_cast<uint8_t>(
+            strnlen(reinterpret_cast<const char *>(stationConfig.sta.password), DeviceLayer::Internal::kMaxWiFiKeyLength));
 
-    if (!CanCastTo<uint8_t>(ssidLen))
-    {
-        return CHIP_ERROR_INCORRECT_STATE;
+        memcpy(mStagingNetwork.credentials, stationConfig.sta.password, credentialsLen);
+        mStagingNetwork.credentialsLen = credentialsLen;
     }
-    mSavedNetwork.ssidLen = static_cast<uint8_t>(ssidLen);
 
-    mStagingNetwork        = mSavedNetwork;
     mpScanCallback         = nullptr;
     mpConnectCallback      = nullptr;
     mpStatusChangeCallback = networkStatusChangeCallback;
-    return err;
+
+    // If the network configuration backup exists, it means that the device has been rebooted with
+    // the fail-safe armed. Since ESP-WiFi persists all wifi credentials changes, the backup must
+    // be restored on the boot. If there's no backup, the below function is a no-op.
+    RevertConfiguration();
+
+    return CHIP_NO_ERROR;
 }
 
 void ESPWiFiDriver::Shutdown()
@@ -137,17 +129,51 @@ void ESPWiFiDriver::Shutdown()
 
 CHIP_ERROR ESPWiFiDriver::CommitConfiguration()
 {
-    ReturnErrorOnFailure(PersistedStorage::KeyValueStoreMgr().Put(kWiFiSSIDKeyName, mStagingNetwork.ssid, mStagingNetwork.ssidLen));
-    ReturnErrorOnFailure(PersistedStorage::KeyValueStoreMgr().Put(kWiFiCredentialsKeyName, mStagingNetwork.credentials,
-                                                                  mStagingNetwork.credentialsLen));
-    mSavedNetwork = mStagingNetwork;
+    PersistedStorage::KeyValueStoreMgr().Delete(kWiFiSSIDKeyName);
+    PersistedStorage::KeyValueStoreMgr().Delete(kWiFiCredentialsKeyName);
+
     return CHIP_NO_ERROR;
 }
 
 CHIP_ERROR ESPWiFiDriver::RevertConfiguration()
 {
-    mStagingNetwork = mSavedNetwork;
-    return CHIP_NO_ERROR;
+    WiFiNetwork network;
+    Network configuredNetwork;
+    size_t ssidLen        = 0;
+    size_t credentialsLen = 0;
+
+    CHIP_ERROR error = PersistedStorage::KeyValueStoreMgr().Get(kWiFiSSIDKeyName, network.ssid, sizeof(network.ssid), &ssidLen);
+    ReturnErrorCodeIf(error == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND, CHIP_NO_ERROR);
+    VerifyOrExit(CanCastTo<uint8_t>(ssidLen), error = CHIP_ERROR_INTERNAL);
+    VerifyOrExit(PersistedStorage::KeyValueStoreMgr().Get(kWiFiCredentialsKeyName, network.credentials, sizeof(network.credentials),
+                                                          &credentialsLen) == CHIP_NO_ERROR,
+                 error = CHIP_ERROR_INTERNAL);
+    VerifyOrExit(CanCastTo<uint8_t>(credentialsLen), error = CHIP_ERROR_INTERNAL);
+
+    network.ssidLen        = static_cast<uint8_t>(ssidLen);
+    network.credentialsLen = static_cast<uint8_t>(credentialsLen);
+    mStagingNetwork        = network;
+
+    if (GetConfiguredNetwork(configuredNetwork) == CHIP_NO_ERROR)
+    {
+        VerifyOrExit(!NetworkMatch(mStagingNetwork, ByteSpan(configuredNetwork.networkID, configuredNetwork.networkIDLen)),
+                     error = CHIP_NO_ERROR);
+    }
+
+    if (error == CHIP_NO_ERROR)
+    {
+        // ConnectWiFiNetwork can work with empty mStagingNetwork (ssidLen = 0).
+        error = ConnectWiFiNetwork(reinterpret_cast<const char *>(mStagingNetwork.ssid), mStagingNetwork.ssidLen,
+                                   reinterpret_cast<const char *>(mStagingNetwork.credentials), mStagingNetwork.credentialsLen);
+    }
+
+exit:
+
+    // Remove the backup.
+    PersistedStorage::KeyValueStoreMgr().Delete(kWiFiSSIDKeyName);
+    PersistedStorage::KeyValueStoreMgr().Delete(kWiFiCredentialsKeyName);
+
+    return error;
 }
 
 bool ESPWiFiDriver::NetworkMatch(const WiFiNetwork & network, ByteSpan networkId)
@@ -163,6 +189,7 @@ Status ESPWiFiDriver::AddOrUpdateNetwork(ByteSpan ssid, ByteSpan credentials, Mu
     VerifyOrReturnError(mStagingNetwork.ssidLen == 0 || NetworkMatch(mStagingNetwork, ssid), Status::kBoundsExceeded);
     VerifyOrReturnError(credentials.size() <= sizeof(mStagingNetwork.credentials), Status::kOutOfRange);
     VerifyOrReturnError(ssid.size() <= sizeof(mStagingNetwork.ssid), Status::kOutOfRange);
+    VerifyOrReturnError(BackupConfiguration() == CHIP_NO_ERROR, Status::kUnknownError);
 
     memcpy(mStagingNetwork.credentials, credentials.data(), credentials.size());
     mStagingNetwork.credentialsLen = static_cast<decltype(mStagingNetwork.credentialsLen)>(credentials.size());
@@ -178,6 +205,7 @@ Status ESPWiFiDriver::RemoveNetwork(ByteSpan networkId, MutableCharSpan & outDeb
     outDebugText.reduce_size(0);
     outNetworkIndex = 0;
     VerifyOrReturnError(NetworkMatch(mStagingNetwork, networkId), Status::kNetworkIDNotFound);
+    VerifyOrReturnError(BackupConfiguration() == CHIP_NO_ERROR, Status::kUnknownError);
 
     // Use empty ssid for representing invalid network
     mStagingNetwork.ssidLen = 0;
@@ -273,6 +301,7 @@ void ESPWiFiDriver::ConnectNetwork(ByteSpan networkId, ConnectCallback * callbac
     const uint32_t secToMiliSec = 1000;
 
     VerifyOrExit(NetworkMatch(mStagingNetwork, networkId), networkingStatus = Status::kNetworkIDNotFound);
+    VerifyOrExit(BackupConfiguration() == CHIP_NO_ERROR, networkingStatus = Status::kUnknownError);
     VerifyOrExit(mpConnectCallback == nullptr, networkingStatus = Status::kUnknownError);
     ChipLogProgress(NetworkProvisioning, "ESP NetworkCommissioningDelegate: SSID: %.*s", static_cast<int>(networkId.size()),
                     networkId.data());
@@ -484,6 +513,19 @@ bool ESPWiFiDriver::WiFiNetworkIterator::Next(Network & item)
     return true;
 }
 
+CHIP_ERROR ESPWiFiDriver::BackupConfiguration()
+{
+    CHIP_ERROR err = PersistedStorage::KeyValueStoreMgr().Get(kWiFiSSIDKeyName, nullptr, 0);
+    if (err == CHIP_NO_ERROR || err == CHIP_ERROR_BUFFER_TOO_SMALL)
+    {
+        return CHIP_NO_ERROR;
+    }
+    ReturnErrorOnFailure(PersistedStorage::KeyValueStoreMgr().Put(kWiFiCredentialsKeyName, mStagingNetwork.credentials,
+                                                                  mStagingNetwork.credentialsLen));
+    ReturnErrorOnFailure(PersistedStorage::KeyValueStoreMgr().Put(kWiFiSSIDKeyName, mStagingNetwork.ssid, mStagingNetwork.ssidLen));
+    return CHIP_NO_ERROR;
+}
+
 } // namespace NetworkCommissioning
 } // namespace DeviceLayer
 } // namespace chip

src/platform/ESP32/NetworkCommissioningDriver.h

@@ -133,8 +133,8 @@ class ESPWiFiDriver final : public WiFiDriver
 private:
     bool NetworkMatch(const WiFiNetwork & network, ByteSpan networkId);
     CHIP_ERROR StartScanWiFiNetworks(ByteSpan ssid);
+    CHIP_ERROR BackupConfiguration();
 
-    WiFiNetwork mSavedNetwork;
     WiFiNetwork mStagingNetwork;
     ScanCallback * mpScanCallback;
     ConnectCallback * mpConnectCallback;