Update prepareIpReachabilityMonitorIpv4AddressResolutionTest
This CL updates prepareIpReachabilityMonitorIpv4AddressResolutionTest
behavior by responding to the ARP probe for the default gateway during
address resolution, which makes the neighbor as reachable. After that,
send a broadcast gratuitous ARP with a different mac address, the tap
interface will change the default gateway neighbor state from REACHABLE
to STALE, and then sending another UDP packet to default gateway will
force the state transit from STALE to DELAY, given the test code intends
not to respond to this UDP packet, after DELAY_FIRST_PROBE_TIME the
state will transit from DELAY to PROBE and start sending ARP probes
again, test case may or may not respond to the probe, depending on
whether a NUD failure is expected then.
Bug: 382194967
Test: atest NetworkStackRootTests
Test: atest NetworkStackIntegrationTests
Change-Id: I95c5711d8c535999b68b3955716567b43313a578
diff --git a/tests/integration/common/android/net/ip/IpClientIntegrationTestCommon.java b/tests/integration/common/android/net/ip/IpClientIntegrationTestCommon.java
index f2ba3e5..8f46b3b 100644
--- a/tests/integration/common/android/net/ip/IpClientIntegrationTestCommon.java
+++ b/tests/integration/common/android/net/ip/IpClientIntegrationTestCommon.java
@@ -323,6 +323,8 @@
// when IpClientLinkObserver sees the RTM_NEWADDR netlink events.
private static final long TEST_LIFETIME_TOLERANCE_MS = 4_000L;
private static final long TEST_POLL_NEIGHBOR_PARAMETER_MS = 500L;
+ private static final int TEST_ARP_LOCKTIME_MS = 1500;
+ private static final int TEST_DELAY_FIRST_PROBE_TIME_S = 2;
@Rule
public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
@@ -959,6 +961,12 @@
}
}
+ private void setNudDelayFirstProbeTime(int delay) throws IOException {
+ final String cmd = "echo " + delay + " > proc/sys/net/ipv4/neigh/" + mIfaceName
+ + "/delay_first_probe_time";
+ InstrumentationRegistry.getInstrumentation().getUiAutomation().executeShellCommand(cmd);
+ }
+
private int getNeighborParameterUcastSolicit(String ifaceName) throws IOException {
final String ucast_solicit = getOneLineCommandOutput(
"su root cat proc/sys/net/ipv6/neigh/" + ifaceName + "/ucast_solicit");
@@ -1235,6 +1243,11 @@
mPacketReader.sendResponse(packet);
}
+ private void sendGratuitousArp(MacAddress srcMac, Inet4Address targetIp) throws IOException {
+ sendArpReply(ETHER_BROADCAST /* dstMac */, srcMac.toByteArray() /* srcMac */, targetIp,
+ targetIp /* sender IP */);
+ }
+
private void startIpClientProvisioning(final ProvisioningConfiguration cfg) throws Exception {
mIIpClient.startProvisioning(cfg.toStableParcelable());
}
@@ -4314,7 +4327,47 @@
NudEventType.NUD_POST_ROAMING_MAC_ADDRESS_CHANGED);
}
- private void prepareIpReachabilityMonitorIpv4AddressResolutionTest() throws Exception {
+ private ArpPacket expectAndRespondToArpRequest(MacAddress srcMac,
+ Inet4Address targetIp) throws Exception {
+ final ArpPacket request = getNextArpPacket();
+ assertArpRequest(request, targetIp);
+ sendArpReply(request.senderHwAddress.toByteArray() /* dst */, srcMac.toByteArray(),
+ request.senderIp /* target IP */, targetIp /* sender IP */);
+ return request;
+ }
+
+ /**
+ * A function helper to set up the steps to verify NUD (neighbor unreachable detection) probes
+ * for IPv4 hosts. This function helper intends to respond to the ARP probes for the default
+ * gateway during address resolution if the param shouldMakeNeighborReachableFirst is true,
+ * which makes the default gateway reachable first, and then sending a gratuitous ARP with a
+ * different mac address, it will override the ARP entry on the tap interface, as a result, it
+ * should do the address resolution again. The param shouldMakeNeighborReachableFirst depends on
+ * the specific test case.
+ *
+ * If a specific test case expectes to see an NUD failure after that, then it should not respond
+ * to any upcoming ARP probes. The packet order example as below,
+ *
+ * 37 0.0.0.0 255.255.255.255 DHCP 338 DHCP Discover - Transaction ID 0xf367c95c
+ * 38 192.168.1.100 192.168.1.2 DHCP 360 DHCP ACK - Transaction ID 0xf367c95c
+ *
+ * 45 66:64:50:87:c3:22 ARP 48 Who has 192.168.1.100? Tell 192.168.1.2
+ * 46 Google_22:33:44 ARP 48 192.168.1.100 is at 00:1a:11:22:33:44
+ * 47 192.168.1.2 192.168.1.100 UDP 148 47467 1234 Len=100
+ *
+ * 76 Google_22:33:55 ARP 48 Gratuitous ARP for 192.168.1.100 (Reply) (duplicate use of 192.168.1.100 detected!)
+ * 77 192.168.1.2 192.168.1.100 UDP 148 38374 1234 Len=100
+ *
+ * 92 66:64:50:87:c3:22 ARP 48 Who has 192.168.1.100? Tell 192.168.1.2
+ * 93 66:64:50:87:c3:22 ARP 48 Who has 192.168.1.100? Tell 192.168.1.2
+ * ...
+ * 116 66:64:50:87:c3:22 ARP 48 Who has 192.168.1.100? Tell 192.168.1.2
+ */
+ private void prepareIpReachabilityMonitorIpv4AddressResolutionTest(
+ boolean shouldMakeNeighborReachableFirst) throws Exception {
+ // Reduce the delay first probe time from 5s to 2s, speed up the test duration and we can
+ // still use PACKET_TIMEOUT_MS to wait for the next upcoming ARP packet.
+ setNudDelayFirstProbeTime(TEST_DELAY_FIRST_PROBE_TIME_S);
mNetworkAgentThread =
new HandlerThread(IpClientIntegrationTestCommon.class.getSimpleName());
mNetworkAgentThread.start();
@@ -4333,17 +4386,35 @@
runAsShell(MANAGE_TEST_NETWORKS, () -> createTestNetworkAgentAndRegister(lp));
- // Send a UDP packet to IPv4 DNS server to trigger address resolution process for IPv4
- // on-link DNS server or default router.
- final Random random = new Random();
- final byte[] data = new byte[100];
- random.nextBytes(data);
- sendUdpPacketToNetwork(mNetworkAgent.getNetwork(), SERVER_ADDR, 1234 /* port */, data);
+ // Send a UDP packet to IPv4 on-link DNS server to trigger address resolution process for
+ // the default gateway, respond to the broadcast ARP probe and make the default gateway as
+ // reachable.
+ sendPacketToPeer(SERVER_ADDR);
+ if (shouldMakeNeighborReachableFirst) {
+ final ArpPacket request = expectAndRespondToArpRequest(ROUTER_MAC, SERVER_ADDR);
+ assertNotNull(request);
+ verifyRestoringNeighborParametersToSteadyState();
+
+ // Wait the locktime expires then we are able to override ARP entry by sending a
+ // gratuitous ARP with a different MAC address, see locktime sysctl on
+ // https://man7.org/linux/man-pages/man7/arp.7.html.
+ Thread.sleep(TEST_ARP_LOCKTIME_MS);
+
+ // Send a gratuitous ARP to override the default gateway MAC address, this makes the
+ // default gateway become stale in the ARP entry, sending another UDP packet to the
+ // default gateway make it transit to DELAY state. If no reachability confirmation is
+ // received within DELAY_FIRST_PROBE_TIME seconds of entering the DELAY state, kernel
+ // goes to PROBE state and start probing, see RFC 4861 section 7.3.2.
+ final MacAddress newMac = MacAddress.fromString("00:1A:11:22:33:55");
+ sendGratuitousArp(newMac, SERVER_ADDR);
+ sendPacketToPeer(SERVER_ADDR);
+ }
}
private void doTestIpReachabilityMonitor_replyBroadcastArpRequestWithDiffMacAddresses(
boolean disconnect) throws Exception {
- prepareIpReachabilityMonitorIpv4AddressResolutionTest();
+ prepareIpReachabilityMonitorIpv4AddressResolutionTest(
+ false /* shouldMakeNeighborReachableFirst */);
// Respond to the broadcast ARP request.
final ArpPacket request = getNextArpPacket();
@@ -4351,7 +4422,7 @@
sendArpReply(request.senderHwAddress.toByteArray() /* dst */, ROUTER_MAC_BYTES /* srcMac */,
request.senderIp /* target IP */, SERVER_ADDR /* sender IP */);
- Thread.sleep(1500);
+ Thread.sleep(TEST_ARP_LOCKTIME_MS);
// Reply with a different MAC address but the same server IP.
final MacAddress gateway = MacAddress.fromString("00:11:22:33:44:55");
@@ -4389,7 +4460,9 @@
@Flag(name = IP_REACHABILITY_IGNORE_ORGANIC_NUD_FAILURE_VERSION, enabled = true)
public void testIpReachabilityMonitor_ignoreIpv4DefaultRouterOrganicNudFailure()
throws Exception {
- prepareIpReachabilityMonitorIpv4AddressResolutionTest();
+ prepareIpReachabilityMonitorIpv4AddressResolutionTest(
+ true /* shouldMakeNeighborReachableFirst */
+ );
ArpPacket packet;
while ((packet = getNextArpPacket(TEST_TIMEOUT_MS)) != null) {
@@ -4399,14 +4472,14 @@
}
@Test
- @Flag(name = IP_REACHABILITY_IGNORE_NEVER_REACHABLE_NEIGHBOR_VERSION, enabled = false)
@Flag(name = IP_REACHABILITY_IGNORE_ORGANIC_NUD_FAILURE_VERSION, enabled = false)
public void testIpReachabilityMonitor_ignoreIpv4DefaultRouterOrganicNudFailure_flagoff()
throws Exception {
- prepareIpReachabilityMonitorIpv4AddressResolutionTest();
+ prepareIpReachabilityMonitorIpv4AddressResolutionTest(
+ true /* shouldMakeNeighborReachableFirst */);
ArpPacket packet;
- while ((packet = getNextArpPacket(TEST_TIMEOUT_MS)) != null) {
+ while ((packet = getNextArpPacket(PACKET_TIMEOUT_MS)) != null) {
// wait address resolution to complete.
}
final ArgumentCaptor<ReachabilityLossInfoParcelable> lossInfoCaptor =
