[BR02] Implement isUidNetworkingBlocked
This is needed for data stall detection mechanism in NetworkStack
to get the information about whether the network is blocked for
a given uid and conditions. Because the API will be called
frequently from NetworkStack to resolve all status for all uids
on the device, the API cannot call into the service which
creates IPC. Instead, the API need to directly access bpf maps
in the user process to retrieve the status. In this case the
user process is the network stack, the access control is provided
by linux file permission and selinux.
Test: atest FrameworksNetTests:android.net.connectivity.android.net.BpfNetMapsReaderTest
Test: atest FrameworksNetTests:android.net.connectivity.android.net.ConnectivityManagerTest
NO_IFTTT=Refactor only change for firewall chains definitions
Bug: 297836825
Change-Id: Iaf983b71ec98cbfe5152dcfade8a3120f938f135
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 32058a4..ad76012 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -6198,6 +6198,36 @@
}
}
+ /**
+ * Return whether the network is blocked for the given uid.
+ *
+ * Similar to {@link NetworkPolicyManager#isUidNetworkingBlocked}, but directly reads the BPF
+ * maps and therefore considerably faster. For use by the NetworkStack process only.
+ *
+ * @param uid The target uid.
+ * @return True if all networking is blocked. Otherwise, false.
+ * @throws IllegalStateException if the map cannot be opened.
+ * @throws ServiceSpecificException if the read fails.
+ * @hide
+ */
+ // This isn't protected by a standard Android permission since it can't
+ // afford to do IPC for performance reasons. Instead, the access control
+ // is provided by linux file group permission AID_NET_BW_ACCT and the
+ // selinux context fs_bpf_net*.
+ // Only the system server process and the network stack have access.
+ // TODO: Expose api when ready.
+ // @SystemApi(client = MODULE_LIBRARIES)
+ @RequiresApi(Build.VERSION_CODES.TIRAMISU) // BPF maps were only mainlined in T
+ @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
+ public boolean isUidNetworkingBlocked(int uid) {
+ final BpfNetMapsReader reader = BpfNetMapsReader.getInstance();
+
+ return reader.isUidBlockedByFirewallChains(uid);
+
+ // TODO: If isNetworkMetered is true, check the data saver switch, penalty box
+ // and happy box rules.
+ }
+
/** @hide */
public IBinder getCompanionDeviceManagerProxyService() {
try {