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Merge "Support learning the NAT64 prefix from two different sources." am: 204b31920f am: a00f03dd61

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Change-Id: I0c7e48c0b16fe09269ced98712bd636105f46a5c
This commit is contained in:
Lorenzo Colitti
2020-04-20 11:37:18 +00:00
committed by Automerger Merge Worker
parent 4d894c7e58 a00f03dd61
commit 27bb67c35b
4 changed files with 179 additions and 24 deletions
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1
services/core/java/com/android/server/ConnectivityService.java
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@@ -5889,6 +5889,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
private void processLinkPropertiesFromAgent(NetworkAgentInfo nai, LinkProperties lp) {
lp.ensureDirectlyConnectedRoutes();
nai.clatd.setNat64PrefixFromRa(lp.getNat64Prefix());
}
private void updateLinkProperties(NetworkAgentInfo networkAgent, LinkProperties newLp,

69
services/core/java/com/android/server/connectivity/Nat464Xlat.java
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@@ -81,15 +81,23 @@ public class Nat464Xlat extends BaseNetworkObserver {
RUNNING, // start() called, and the stacked iface is known to be up.
}
/** NAT64 prefix currently in use. Only valid in STARTING or RUNNING states. */
/**
* NAT64 prefix currently in use. Only valid in STARTING or RUNNING states.
* Used, among other things, to avoid updates when switching from a prefix learned from one
* source (e.g., RA) to the same prefix learned from another source (e.g., RA).
*/
private IpPrefix mNat64PrefixInUse;
/** NAT64 prefix (if any) discovered from DNS via RFC 7050. */
private IpPrefix mNat64PrefixFromDns;
/** NAT64 prefix (if any) learned from the network via RA. */
private IpPrefix mNat64PrefixFromRa;
private String mBaseIface;
private String mIface;
private Inet6Address mIPv6Address;
private State mState = State.IDLE;
private boolean mPrefixDiscoveryRunning;
public Nat464Xlat(NetworkAgentInfo nai, INetd netd, IDnsResolver dnsResolver,
INetworkManagementService nmService) {
mDnsResolver = dnsResolver;
@@ -138,15 +146,6 @@ public class Nat464Xlat extends BaseNetworkObserver {
return requiresClat(nai) && lp != null && lp.getNat64Prefix() != null;
}
/**
* @return true if we have started prefix discovery and not yet stopped it (regardless of
* whether it is still running or has succeeded).
* A true result corresponds to internal states DISCOVERING, STARTING and RUNNING.
*/
public boolean isPrefixDiscoveryStarted() {
return mState == State.DISCOVERING || isStarted();
}
/**
* @return true if clatd has been started and has not yet stopped.
* A true result corresponds to internal states STARTING and RUNNING.
@@ -181,7 +180,7 @@ public class Nat464Xlat extends BaseNetworkObserver {
return;
}
mNat64PrefixInUse = getNat64Prefix();
mNat64PrefixInUse = selectNat64Prefix();
String addrStr = null;
try {
addrStr = mNetd.clatdStart(baseIface, mNat64PrefixInUse.toString());
@@ -218,8 +217,14 @@ public class Nat464Xlat extends BaseNetworkObserver {
mNat64PrefixInUse = null;
mIface = null;
mBaseIface = null;
if (requiresClat(mNetwork)) {
mState = State.DISCOVERING;
if (isPrefixDiscoveryNeeded()) {
if (!mPrefixDiscoveryRunning) {
startPrefixDiscovery();
} else {
// Prefix discovery is already running. Nothing to do.
mState = State.DISCOVERING;
}
} else {
stopPrefixDiscovery(); // Enters IDLE state.
}
@@ -283,6 +288,7 @@ public class Nat464Xlat extends BaseNetworkObserver {
Slog.e(TAG, "Error starting prefix discovery on netId " + getNetId() + ": " + e);
}
mState = State.DISCOVERING;
mPrefixDiscoveryRunning = true;
}
private void stopPrefixDiscovery() {
@@ -292,10 +298,18 @@ public class Nat464Xlat extends BaseNetworkObserver {
Slog.e(TAG, "Error stopping prefix discovery on netId " + getNetId() + ": " + e);
}
mState = State.IDLE;
mPrefixDiscoveryRunning = false;
}
private boolean isPrefixDiscoveryNeeded() {
// If there is no NAT64 prefix in the RA, prefix discovery is always needed. It cannot be
// stopped after it succeeds, because stopping it will cause netd to report that the prefix
// has been removed, and that will cause us to stop clatd.
return requiresClat(mNetwork) && mNat64PrefixFromRa == null;
}
private void maybeHandleNat64PrefixChange() {
final IpPrefix newPrefix = getNat64Prefix();
final IpPrefix newPrefix = selectNat64Prefix();
if (!Objects.equals(mNat64PrefixInUse, newPrefix)) {
Slog.d(TAG, "NAT64 prefix changed from " + mNat64PrefixInUse + " to "
+ newPrefix);
@@ -314,13 +328,10 @@ public class Nat464Xlat extends BaseNetworkObserver {
// TODO: turn this class into a proper StateMachine. http://b/126113090
switch (mState) {
case IDLE:
if (requiresClat(mNetwork)) {
// Network is detected to be IPv6-only.
// TODO: consider going to STARTING directly if the NAT64 prefix is already
// known. This would however result in clatd running without prefix discovery
// running, which might be a surprising combination.
if (isPrefixDiscoveryNeeded()) {
startPrefixDiscovery(); // Enters DISCOVERING state.
return;
} else if (requiresClat(mNetwork)) {
start(); // Enters STARTING state.
}
break;
@@ -351,8 +362,20 @@ public class Nat464Xlat extends BaseNetworkObserver {
}
}
private IpPrefix getNat64Prefix() {
return mNat64PrefixFromDns;
/**
* Picks a NAT64 prefix to use. Always prefers the prefix from the RA if one is received from
* both RA and DNS, because the prefix in the RA has better security and updatability, and will
* almost always be received first anyway.
*
* Any network that supports legacy hosts will support discovering the DNS64 prefix via DNS as
* well. If the prefix from the RA is withdrawn, fall back to that for reliability purposes.
*/
private IpPrefix selectNat64Prefix() {
return mNat64PrefixFromRa != null ? mNat64PrefixFromRa : mNat64PrefixFromDns;
}
public void setNat64PrefixFromRa(IpPrefix prefix) {
mNat64PrefixFromRa = prefix;
}
public void setNat64PrefixFromDns(IpPrefix prefix) {
@@ -367,7 +390,7 @@ public class Nat464Xlat extends BaseNetworkObserver {
public void fixupLinkProperties(@NonNull LinkProperties oldLp, @NonNull LinkProperties lp) {
// This must be done even if clatd is not running, because otherwise shouldStartClat would
// never return true.
lp.setNat64Prefix(getNat64Prefix());
lp.setNat64Prefix(selectNat64Prefix());
if (!isRunning()) {
return;

89
tests/net/java/com/android/server/ConnectivityServiceTest.java
View File

@@ -6179,6 +6179,95 @@ public class ConnectivityServiceTest {
mCm.unregisterNetworkCallback(networkCallback);
}
private void expectNat64PrefixChange(TestableNetworkCallback callback,
TestNetworkAgentWrapper agent, IpPrefix prefix) {
callback.expectLinkPropertiesThat(agent, x -> Objects.equals(x.getNat64Prefix(), prefix));
}
@Test
public void testNat64PrefixMultipleSources() throws Exception {
final String iface = "wlan0";
final String pref64FromRaStr = "64:ff9b::";
final String pref64FromDnsStr = "2001:db8:64::";
final IpPrefix pref64FromRa = new IpPrefix(InetAddress.getByName(pref64FromRaStr), 96);
final IpPrefix pref64FromDns = new IpPrefix(InetAddress.getByName(pref64FromDnsStr), 96);
final IpPrefix newPref64FromRa = new IpPrefix("2001:db8:64:64:64:64::/96");
final NetworkRequest request = new NetworkRequest.Builder()
.addCapability(NET_CAPABILITY_INTERNET)
.build();
final TestNetworkCallback callback = new TestNetworkCallback();
mCm.registerNetworkCallback(request, callback);
final LinkProperties baseLp = new LinkProperties();
baseLp.setInterfaceName(iface);
baseLp.addLinkAddress(new LinkAddress("2001:db8:1::1/64"));
baseLp.addDnsServer(InetAddress.getByName("2001:4860:4860::6464"));
reset(mMockNetd, mMockDnsResolver);
InOrder inOrder = inOrder(mMockNetd, mMockDnsResolver);
// If a network already has a NAT64 prefix on connect, clatd is started immediately and
// prefix discovery is never started.
LinkProperties lp = new LinkProperties(baseLp);
lp.setNat64Prefix(pref64FromRa);
mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI, lp);
mCellNetworkAgent.connect(false);
final Network network = mCellNetworkAgent.getNetwork();
int netId = network.getNetId();
callback.expectAvailableCallbacksUnvalidated(mCellNetworkAgent);
inOrder.verify(mMockNetd).clatdStart(iface, pref64FromRa.toString());
inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
callback.assertNoCallback();
assertEquals(pref64FromRa, mCm.getLinkProperties(network).getNat64Prefix());
// If the RA prefix is withdrawn, clatd is stopped and prefix discovery is started.
lp.setNat64Prefix(null);
mCellNetworkAgent.sendLinkProperties(lp);
expectNat64PrefixChange(callback, mCellNetworkAgent, null);
inOrder.verify(mMockNetd).clatdStop(iface);
inOrder.verify(mMockDnsResolver).startPrefix64Discovery(netId);
mService.mNetdEventCallback.onNat64PrefixEvent(netId, true /* added */,
pref64FromDnsStr, 96);
expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromDns);
inOrder.verify(mMockNetd).clatdStart(iface, pref64FromDns.toString());
// If the RA prefix reappears, clatd is restarted and prefix discovery is stopped.
lp.setNat64Prefix(pref64FromRa);
mCellNetworkAgent.sendLinkProperties(lp);
expectNat64PrefixChange(callback, mCellNetworkAgent, pref64FromRa);
inOrder.verify(mMockNetd).clatdStop(iface);
inOrder.verify(mMockDnsResolver).stopPrefix64Discovery(netId);
inOrder.verify(mMockNetd).clatdStart(iface, pref64FromRa.toString());
inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
// If the RA prefix changes, clatd is restarted and prefix discovery is not started.
lp.setNat64Prefix(newPref64FromRa);
mCellNetworkAgent.sendLinkProperties(lp);
expectNat64PrefixChange(callback, mCellNetworkAgent, newPref64FromRa);
inOrder.verify(mMockNetd).clatdStop(iface);
inOrder.verify(mMockNetd).clatdStart(iface, newPref64FromRa.toString());
inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
// If the RA prefix changes to the same value, nothing happens.
lp.setNat64Prefix(newPref64FromRa);
mCellNetworkAgent.sendLinkProperties(lp);
callback.assertNoCallback();
assertEquals(newPref64FromRa, mCm.getLinkProperties(network).getNat64Prefix());
inOrder.verify(mMockNetd, never()).clatdStop(iface);
inOrder.verify(mMockNetd, never()).clatdStart(eq(iface), anyString());
inOrder.verify(mMockDnsResolver, never()).stopPrefix64Discovery(netId);
inOrder.verify(mMockDnsResolver, never()).startPrefix64Discovery(netId);
// The transition between no prefix and DNS prefix is tested in testStackedLinkProperties.
callback.assertNoCallback();
mCellNetworkAgent.disconnect();
mCm.unregisterNetworkCallback(callback);
}
@Test
public void testDataActivityTracking() throws Exception {
final TestNetworkCallback networkCallback = new TestNetworkCallback();

44
tests/net/java/com/android/server/connectivity/Nat464XlatTest.java
View File

@@ -60,6 +60,7 @@ public class Nat464XlatTest {
static final String STACKED_IFACE = "v4-test0";
static final LinkAddress ADDR = new LinkAddress("192.0.2.5/29");
static final String NAT64_PREFIX = "64:ff9b::/96";
static final String OTHER_NAT64_PREFIX = "2001:db8:0:64::/96";
static final int NETID = 42;
@Mock ConnectivityService mConnectivity;
@@ -139,7 +140,7 @@ public class Nat464XlatTest {
for (NetworkInfo.DetailedState state : supportedDetailedStates) {
mNai.networkInfo.setDetailedState(state, "reason", "extraInfo");
mNai.linkProperties.setNat64Prefix(new IpPrefix("2001:db8:0:64::/96"));
mNai.linkProperties.setNat64Prefix(new IpPrefix(OTHER_NAT64_PREFIX));
assertRequiresClat(false, mNai);
assertShouldStartClat(false, mNai);
@@ -398,6 +399,47 @@ public class Nat464XlatTest {
verifyNoMoreInteractions(mNetd, mNms, mConnectivity);
}
@Test
public void testNat64PrefixPreference() throws Exception {
final IpPrefix prefixFromDns = new IpPrefix(NAT64_PREFIX);
final IpPrefix prefixFromRa = new IpPrefix(OTHER_NAT64_PREFIX);
Nat464Xlat nat = makeNat464Xlat();
final LinkProperties emptyLp = new LinkProperties();
LinkProperties fixedupLp;
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromDns(prefixFromDns);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(prefixFromDns, fixedupLp.getNat64Prefix());
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromRa(prefixFromRa);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(prefixFromRa, fixedupLp.getNat64Prefix());
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromRa(null);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(prefixFromDns, fixedupLp.getNat64Prefix());
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromRa(prefixFromRa);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(prefixFromRa, fixedupLp.getNat64Prefix());
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromDns(null);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(prefixFromRa, fixedupLp.getNat64Prefix());
fixedupLp = new LinkProperties();
nat.setNat64PrefixFromRa(null);
nat.fixupLinkProperties(emptyLp, fixedupLp);
assertEquals(null, fixedupLp.getNat64Prefix());
}
static void assertIdle(Nat464Xlat nat) {
assertTrue("Nat464Xlat was not IDLE", !nat.isStarted());
}