Merge changes I33bc80cc,Ie84e2cd4

* changes:
  EthernetManagerTest: update tests that bring up tap without carrier
  TestNetworkService: use IFF_NO_CARRIER to bring up iface without carrier

framework/src/android/net/TestNetworkManager.java

@@ -260,7 +260,7 @@ public class TestNetworkManager {
     /**
      * Create a tap interface with or without carrier for testing purposes.
      *
-     * Note: setting carrierUp = false is not supported until kernel version 5.0.
+     * Note: setting carrierUp = false is not supported until kernel version 6.0.
      *
      * @param carrierUp whether the created interface has a carrier or not.
      * @param bringUp whether to bring up the interface before returning it.
@@ -280,6 +280,8 @@ public class TestNetworkManager {
     /**
      * Create a tap interface for testing purposes.
      *
+     * Note: setting carrierUp = false is not supported until kernel version 6.0.
+     *
      * @param carrierUp whether the created interface has a carrier or not.
      * @param bringUp whether to bring up the interface before returning it.
      * @param disableIpv6ProvisioningDelay whether to disable DAD and RS delay.

service/jni/com_android_server_TestNetworkService.cpp

@@ -38,9 +38,14 @@
 #include "jni.h"
 #include <android-base/stringprintf.h>
 #include <android-base/unique_fd.h>
+#include <bpf/KernelVersion.h>
 #include <nativehelper/JNIHelp.h>
 #include <nativehelper/ScopedUtfChars.h>
 
+#ifndef IFF_NO_CARRIER
+#define IFF_NO_CARRIER 0x0040
+#endif
+
 namespace android {
 
 //------------------------------------------------------------------------------
@@ -66,17 +71,21 @@ static int createTunTapImpl(JNIEnv* env, bool isTun, bool hasCarrier, bool setIf
 
     // Allocate interface.
     ifr.ifr_flags = (isTun ? IFF_TUN : IFF_TAP) | IFF_NO_PI;
+    if (!hasCarrier) {
+        // Using IFF_NO_CARRIER is supported starting in kernel version >= 6.0
+        // Up until then, unsupported flags are ignored.
+        if (!bpf::isAtLeastKernelVersion(6, 0, 0)) {
+            throwException(env, EOPNOTSUPP, "IFF_NO_CARRIER not supported", ifr.ifr_name);
+            return -1;
+        }
+        ifr.ifr_flags |= IFF_NO_CARRIER;
+    }
     strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
     if (ioctl(tun.get(), TUNSETIFF, &ifr)) {
         throwException(env, errno, "allocating", ifr.ifr_name);
         return -1;
     }
 
-    if (!hasCarrier) {
-        // disable carrier before setting IFF_UP
-        setTunTapCarrierEnabledImpl(env, iface, tun.get(), hasCarrier);
-    }
-
     // Mark some TAP interfaces as supporting multicast
     if (setIffMulticast && !isTun) {
         base::unique_fd inet6CtrlSock(socket(AF_INET6, SOCK_DGRAM, 0));

tests/cts/net/src/android/net/cts/EthernetManagerTest.kt

@@ -392,7 +392,15 @@ class EthernetManagerTest {
     }
 
     // Setting the carrier up / down relies on TUNSETCARRIER which was added in kernel version 5.0.
-    private fun assumeChangingCarrierSupported() = assumeTrue(isKernelVersionAtLeast("5.0.0"))
+    private fun assumeChangingCarrierSupported() {
+        assumeTrue(isKernelVersionAtLeast("5.0.0"))
+    }
+
+    // Configuring a tap interface without carrier relies on IFF_NO_CARRIER
+    // which was added in kernel version 6.0.
+    private fun assumeCreateInterfaceWithoutCarrierSupported() {
+        assumeTrue(isKernelVersionAtLeast("6.0.0"))
+    }
 
     private fun isAdbOverEthernet(): Boolean {
         // If no ethernet interface is available, adb is not connected over ethernet.
@@ -417,7 +425,7 @@ class EthernetManagerTest {
     }
 
     // WARNING: setting hasCarrier to false requires kernel support. Call
-    // assumeChangingCarrierSupported() at the top of your test.
+    // assumeCreateInterfaceWithoutCarrierSupported() at the top of your test.
     private fun createInterface(hasCarrier: Boolean = true): EthernetTestInterface {
         val iface = EthernetTestInterface(
             context,
@@ -791,15 +799,13 @@ class EthernetManagerTest {
 
     @Test
     fun testNetworkRequest_forInterfaceWhileTogglingCarrier() {
+        assumeCreateInterfaceWithoutCarrierSupported()
         assumeChangingCarrierSupported()
 
         val iface = createInterface(false /* hasCarrier */)
 
         val cb = requestNetwork(ETH_REQUEST)
-        // TUNSETCARRIER races with the bring up code, so the network *can* become available despite
+        cb.assertNeverAvailable()
-        // it being "created with no carrier".
-        // TODO(b/249611919): re-enable assertion once kernel supports IFF_NO_CARRIER.
-        // cb.assertNeverAvailable()
 
         iface.setCarrierEnabled(true)
         cb.expect<Available>()