VPN: Add support for custom DNS (#4637)

Task/Issue URL:
https://app.asana.com/0/488551667048375/1207500898026382/f

### Description
See attached task description

### Steps to test this PR
https://app.asana.com/0/0/1207531536629227/f

Author: karlenDimla

common/common-utils/src/main/java/com/duckduckgo/common/utils/extensions/ActivityExtensions.kt

@@ -44,6 +44,13 @@ fun AppCompatActivity.launchAlwaysOnSystemSettings() {
     startActivity(intent)
 }
 
+@SuppressLint("InlinedApi")
+fun AppCompatActivity.launchSettings() {
+    val intent = Intent(Settings.ACTION_SETTINGS)
+    intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
+    startActivity(intent)
+}
+
 /**
  * Deep links to the battery optimization settings
  * @return `true` if it was able to deep link, otherwise `false`

network-protection/network-protection-impl/src/main/AndroidManifest.xml

@@ -35,16 +35,17 @@
             android:label="@string/netpVpnSettingsTitle"
             android:parentActivityName=".management.NetworkProtectionManagementActivity"
             android:exported="false" />
-        <activity
-            android:name=".settings.NetPNotificationSettingsActivity"
-            android:label="@string/netpVpnNotificationSettingsTitle"
-            android:parentActivityName=".management.NetworkProtectionManagementActivity"
-            android:exported="false" />
         <activity
             android:name=".settings.geoswitching.NetpGeoswitchingActivity"
             android:label="@string/netpGeoswitchingTitle"
             android:parentActivityName="settings.NetPVpnSettingsActivity"
             android:exported="false" />
+
+        <activity
+            android:name=".settings.custom_dns.VpnCustomDnsActivity"
+            android:label="@string/netpCustomDnsSettingText"
+            android:exported="false" />
+
         <receiver
             android:name=".notification.NetPEnableReceiver"
             android:exported="false"

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/WgVpnNetworkStack.kt

@@ -80,7 +80,7 @@ class WgVpnNetworkStack @Inject constructor(
                     // why? no use intercepting encrypted DNS traffic, plus we can't configure any DNS that doesn't support DoT, otherwise Android
                     // will enforce DoT and will stop passing any DNS traffic, resulting in no DNS resolution == connectivity is killed
                     dns = if (privateDns.isEmpty()) wgConfig!!.`interface`.dnsServers else emptySet(),
-                    customDns = netPDefaultConfigProvider.fallbackDns(),
+                    customDns = if (privateDns.isEmpty()) netPDefaultConfigProvider.fallbackDns() else emptySet(),
                     routes = wgConfig!!.`interface`.routes.associate { it.address.hostAddress!! to it.mask },
                     appExclusionList = wgConfig!!.`interface`.excludedApplications,
                 ),

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/config/NetPDefaultConfigProvider.kt

@@ -20,6 +20,7 @@ import com.duckduckgo.common.utils.DispatcherProvider
 import com.duckduckgo.di.scopes.VpnScope
 import com.duckduckgo.networkprotection.impl.exclusion.systemapps.SystemAppsExclusionRepository
 import com.duckduckgo.networkprotection.impl.settings.NetPSettingsLocalConfig
+import com.duckduckgo.networkprotection.impl.settings.NetpVpnSettingsDataStore
 import com.duckduckgo.networkprotection.store.NetPExclusionListRepository
 import com.squareup.anvil.annotations.ContributesBinding
 import java.net.Inet4Address
@@ -39,14 +40,19 @@ interface NetPDefaultConfigProvider {
     fun pcapConfig(): PcapConfig? = null
 }
 
-data class PcapConfig(val filename: String, val snapLen: Int, val fileSize: Int)
+data class PcapConfig(
+    val filename: String,
+    val snapLen: Int,
+    val fileSize: Int,
+)
 
 @ContributesBinding(VpnScope::class)
 class RealNetPDefaultConfigProvider @Inject constructor(
     private val netPExclusionListRepository: NetPExclusionListRepository,
     private val dispatcherProvider: DispatcherProvider,
     private val netPSettingsLocalConfig: NetPSettingsLocalConfig,
     private val systemAppsExclusionRepository: SystemAppsExclusionRepository,
+    private val netpVpnSettingsDataStore: NetpVpnSettingsDataStore,
 ) : NetPDefaultConfigProvider {
     override suspend fun exclusionList(): Set<String> {
         return mutableSetOf<String>().apply {
@@ -70,4 +76,12 @@ class RealNetPDefaultConfigProvider @Inject constructor(
             }
         }
     }
+
+    override fun fallbackDns(): Set<InetAddress> {
+        return netpVpnSettingsDataStore.customDns?.run {
+            runCatching {
+                InetAddress.getAllByName(this).toSet()
+            }.getOrDefault(emptySet())
+        } ?: emptySet()
+    }
 }

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/integration/NetPStateCollector.kt

@@ -27,6 +27,7 @@ import com.duckduckgo.networkprotection.impl.connectionclass.ConnectionQualitySt
 import com.duckduckgo.networkprotection.impl.connectionclass.asConnectionQuality
 import com.duckduckgo.networkprotection.impl.exclusion.systemapps.SystemAppsExclusionRepository
 import com.duckduckgo.networkprotection.impl.settings.NetPSettingsLocalConfig
+import com.duckduckgo.networkprotection.impl.settings.NetpVpnSettingsDataStore
 import com.duckduckgo.networkprotection.impl.subscription.NetpSubscriptionManager
 import com.duckduckgo.networkprotection.impl.subscription.isActive
 import com.duckduckgo.networkprotection.store.NetPExclusionListRepository
@@ -47,6 +48,7 @@ class NetPStateCollector @Inject constructor(
     private val netPGeoswitchingRepository: NetPGeoswitchingRepository,
     private val netpSubscriptionManager: NetpSubscriptionManager,
     private val systemAppsExclusionRepository: SystemAppsExclusionRepository,
+    private val netpVpnSettingsDataStore: NetpVpnSettingsDataStore,
 ) : VpnStateCollectorPlugin {
 
     override suspend fun collectVpnRelatedState(appPackageId: String?): JSONObject {
@@ -67,6 +69,7 @@ class NetPStateCollector @Inject constructor(
                 put("excludeLocalNetworks", netPSettingsLocalConfig.vpnExcludeLocalNetworkRoutes().isEnabled())
                 put("excludedSystemAppCategories", systemAppsExclusionRepository.getExcludedCategories().map { it.name })
                 put("pauseDuringWifiCallsEnabled", netPSettingsLocalConfig.vpnPauseDuringCalls().isEnabled())
+                put("customDNS", !netpVpnSettingsDataStore.customDns.isNullOrEmpty())
             }
         }
     }

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/management/NetworkProtectionManagementActivity.kt

@@ -244,11 +244,19 @@ class NetworkProtectionManagementActivity : DuckDuckGoActivity() {
         if (connectionDetailsData.ipAddress.isNullOrEmpty()) {
             connectionDetails.connectionDetailsIp.gone()
         } else {
+            connectionDetails.connectionDetailsIp.show()
             connectionDetails.connectionDetailsIp.setSecondaryText(connectionDetailsData.ipAddress)
         }
 
         connectionDetails.transmittedText.text = formatFileSize(applicationContext, connectionDetailsData.transmittedData)
         connectionDetails.receivedText.text = formatFileSize(applicationContext, connectionDetailsData.receivedData)
+
+        if (connectionDetailsData.customDns.isNullOrEmpty()) {
+            connectionDetails.connectionDetailsDns.gone()
+        } else {
+            connectionDetails.connectionDetailsDns.show()
+            connectionDetails.connectionDetailsDns.setSecondaryText(connectionDetailsData.customDns)
+        }
     }
 
     private fun ActivityNetpManagementBinding.renderDisconnectedState() {

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/management/NetworkProtectionManagementViewModel.kt

@@ -57,6 +57,7 @@ import com.duckduckgo.networkprotection.impl.management.NetworkProtectionManagem
 import com.duckduckgo.networkprotection.impl.management.NetworkProtectionManagementViewModel.ConnectionState.Disconnected
 import com.duckduckgo.networkprotection.impl.management.NetworkProtectionManagementViewModel.ConnectionState.Unknown
 import com.duckduckgo.networkprotection.impl.pixels.NetworkProtectionPixels
+import com.duckduckgo.networkprotection.impl.settings.NetpVpnSettingsDataStore
 import com.duckduckgo.networkprotection.impl.settings.geoswitching.getDisplayableCountry
 import com.duckduckgo.networkprotection.impl.settings.geoswitching.getEmojiForCountryCode
 import com.duckduckgo.networkprotection.impl.store.NetworkProtectionRepository
@@ -87,6 +88,7 @@ class NetworkProtectionManagementViewModel @Inject constructor(
     private val netPGeoswitchingRepository: NetPGeoswitchingRepository,
     private val netpDataVolumeStore: NetpDataVolumeStore,
     private val netPExclusionListRepository: NetPExclusionListRepository,
+    private val netpVpnSettingsDataStore: NetpVpnSettingsDataStore,
 ) : ViewModel(), DefaultLifecycleObserver {
 
     private val refreshVpnRunningState = MutableStateFlow(System.currentTimeMillis())
@@ -219,11 +221,13 @@ class NetworkProtectionManagementViewModel @Inject constructor(
                 ConnectionDetails(
                     location = serverDetails.location,
                     ipAddress = serverDetails.ipAddress,
+                    customDns = netpVpnSettingsDataStore.customDns,
                 )
             } else {
                 connectionDetailsFlow.value!!.copy(
                     location = serverDetails.location,
                     ipAddress = serverDetails.ipAddress,
+                    customDns = netpVpnSettingsDataStore.customDns,
                 )
             }
         }
@@ -246,12 +250,14 @@ class NetworkProtectionManagementViewModel @Inject constructor(
                                 elapsedConnectedTime = getElapsedTimeString(enabledTime),
                                 transmittedData = dataVolume.transmittedBytes,
                                 receivedData = dataVolume.receivedBytes,
+                                customDns = netpVpnSettingsDataStore.customDns,
                             )
                         } else {
                             connectionDetailsFlow.value!!.copy(
                                 elapsedConnectedTime = getElapsedTimeString(enabledTime),
                                 transmittedData = dataVolume.transmittedBytes,
                                 receivedData = dataVolume.receivedBytes,
+                                customDns = netpVpnSettingsDataStore.customDns,
                             )
                         }
                     }
@@ -406,6 +412,7 @@ class NetworkProtectionManagementViewModel @Inject constructor(
         val elapsedConnectedTime: String? = null,
         val transmittedData: Long = 0L,
         val receivedData: Long = 0L,
+        val customDns: String? = null,
     )
 
     enum class ConnectionState {

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/pixels/NetworkProtectionPixelNames.kt

@@ -140,4 +140,8 @@ enum class NetworkProtectionPixelNames(
     NETP_SERVER_MIGRATION_ATTEMPT_SUCCESS_DAILY("m_netp_ev_server_migration_attempt_success_d", enqueue = true),
     NETP_SERVER_MIGRATION_ATTEMPT_FAILED("m_netp_ev_server_migration_attempt_failed_c", enqueue = true),
     NETP_SERVER_MIGRATION_ATTEMPT_FAILED_DAILY("m_netp_ev_server_migration_attempt_failed_d", enqueue = true),
+    NETP_UPDATE_CUSTOM_DNS("m_netp_ev_update_dns_custom_c", enqueue = true),
+    NETP_UPDATE_CUSTOM_DNS_DAILY("m_netp_ev_update_dns_custom_d", enqueue = true),
+    NETP_UPDATE_DEFAULT_DNS("m_netp_ev_update_dns_default_c", enqueue = true),
+    NETP_UPDATE_DEFAULT_DNS_DAILY("m_netp_ev_update_dns_default_d", enqueue = true),
 }

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/pixels/NetworkProtectionPixels.kt

@@ -286,6 +286,10 @@ interface NetworkProtectionPixels {
     fun reportServerMigrationAttempt()
     fun reportServerMigrationAttemptSuccess()
     fun reportServerMigrationAttemptFailed()
+
+    fun reportCustomDnsSet()
+
+    fun reportDefaultDnsSet()
 }
 
 @ContributesBinding(AppScope::class)
@@ -594,6 +598,16 @@ class RealNetworkProtectionPixel @Inject constructor(
         tryToFireDailyPixel(NETP_SERVER_MIGRATION_ATTEMPT_FAILED_DAILY)
     }
 
+    override fun reportCustomDnsSet() {
+        firePixel(NETP_UPDATE_CUSTOM_DNS)
+        tryToFireDailyPixel(NETP_UPDATE_CUSTOM_DNS_DAILY)
+    }
+
+    override fun reportDefaultDnsSet() {
+        firePixel(NETP_UPDATE_DEFAULT_DNS)
+        tryToFireDailyPixel(NETP_UPDATE_DEFAULT_DNS_DAILY)
+    }
+
     private fun firePixel(
         p: NetworkProtectionPixelNames,
         payload: Map<String, String> = emptyMap(),