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Add basic resolution of Private DNS hostname
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Test: as follows
    - built
    - flashed
    - booted
Bug: 34953048
Bug: 64133961
Change-Id: I0a2289ea51a9294352c91d2ead23730d9b0333a5
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Erik Kline committed Jan 17, 2018
1 parent fa61875 commit a24d459
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Showing 4 changed files with 362 additions and 92 deletions.
177 changes: 144 additions & 33 deletions services/core/java/com/android/server/ConnectivityService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -131,6 +131,7 @@
import com.android.server.am.BatteryStatsService;
import com.android.server.connectivity.DataConnectionStats;
import com.android.server.connectivity.DnsManager;
import com.android.server.connectivity.DnsManager.PrivateDnsConfig;
import com.android.server.connectivity.IpConnectivityMetrics;
import com.android.server.connectivity.KeepaliveTracker;
import com.android.server.connectivity.LingerMonitor;
Expand Down Expand Up @@ -399,6 +400,9 @@ private enum UnneededFor {
*/
private static final int EVENT_REVALIDATE_NETWORK = 36;

// Handle changes in Private DNS settings.
private static final int EVENT_PRIVATE_DNS_SETTINGS_CHANGED = 37;

private static String eventName(int what) {
return sMagicDecoderRing.get(what, Integer.toString(what));
}
Expand Down Expand Up @@ -863,6 +867,7 @@ protected ConnectivityService(Context context, INetworkManagementService netMana
mMultinetworkPolicyTracker.start();

mDnsManager = new DnsManager(mContext, mNetd, mSystemProperties);
registerPrivateDnsSettingsCallbacks();
}

private Tethering makeTethering() {
Expand Down Expand Up @@ -923,6 +928,12 @@ private void registerSettingsCallbacks() {
EVENT_CONFIGURE_MOBILE_DATA_ALWAYS_ON);
}

private void registerPrivateDnsSettingsCallbacks() {
for (Uri u : DnsManager.getPrivateDnsSettingsUris()) {
mSettingsObserver.observe(u, EVENT_PRIVATE_DNS_SETTINGS_CHANGED);
}
}

private synchronized int nextNetworkRequestId() {
return mNextNetworkRequestId++;
}
Expand Down Expand Up @@ -2086,36 +2097,59 @@ private boolean maybeHandleNetworkMonitorMessage(Message msg) {
synchronized (mNetworkForNetId) {
nai = mNetworkForNetId.get(msg.arg2);
}
if (nai != null) {
final boolean valid =
(msg.arg1 == NetworkMonitor.NETWORK_TEST_RESULT_VALID);
final boolean wasValidated = nai.lastValidated;
final boolean wasDefault = isDefaultNetwork(nai);
if (DBG) log(nai.name() + " validation " + (valid ? "passed" : "failed") +
(msg.obj == null ? "" : " with redirect to " + (String)msg.obj));
if (valid != nai.lastValidated) {
if (wasDefault) {
metricsLogger().defaultNetworkMetrics().logDefaultNetworkValidity(
SystemClock.elapsedRealtime(), valid);
}
final int oldScore = nai.getCurrentScore();
nai.lastValidated = valid;
nai.everValidated |= valid;
updateCapabilities(oldScore, nai, nai.networkCapabilities);
// If score has changed, rebroadcast to NetworkFactories. b/17726566
if (oldScore != nai.getCurrentScore()) sendUpdatedScoreToFactories(nai);
if (nai == null) break;

final boolean valid = (msg.arg1 == NetworkMonitor.NETWORK_TEST_RESULT_VALID);
final boolean wasValidated = nai.lastValidated;
final boolean wasDefault = isDefaultNetwork(nai);

final PrivateDnsConfig privateDnsCfg = (msg.obj instanceof PrivateDnsConfig)
? (PrivateDnsConfig) msg.obj : null;
final String redirectUrl = (msg.obj instanceof String) ? (String) msg.obj : "";

final boolean reevaluationRequired;
final String logMsg;
if (valid) {
reevaluationRequired = updatePrivateDns(nai, privateDnsCfg);
logMsg = (DBG && (privateDnsCfg != null))
? " with " + privateDnsCfg.toString() : "";
} else {
reevaluationRequired = false;
logMsg = (DBG && !TextUtils.isEmpty(redirectUrl))
? " with redirect to " + redirectUrl : "";
}
if (DBG) {
log(nai.name() + " validation " + (valid ? "passed" : "failed") + logMsg);
}
// If there is a change in Private DNS configuration,
// trigger reevaluation of the network to test it.
if (reevaluationRequired) {
nai.networkMonitor.sendMessage(
NetworkMonitor.CMD_FORCE_REEVALUATION, Process.SYSTEM_UID);
break;
}
if (valid != nai.lastValidated) {
if (wasDefault) {
metricsLogger().defaultNetworkMetrics().logDefaultNetworkValidity(
SystemClock.elapsedRealtime(), valid);
}
updateInetCondition(nai);
// Let the NetworkAgent know the state of its network
Bundle redirectUrlBundle = new Bundle();
redirectUrlBundle.putString(NetworkAgent.REDIRECT_URL_KEY, (String)msg.obj);
nai.asyncChannel.sendMessage(
NetworkAgent.CMD_REPORT_NETWORK_STATUS,
(valid ? NetworkAgent.VALID_NETWORK : NetworkAgent.INVALID_NETWORK),
0, redirectUrlBundle);
if (wasValidated && !nai.lastValidated) {
handleNetworkUnvalidated(nai);
}
final int oldScore = nai.getCurrentScore();
nai.lastValidated = valid;
nai.everValidated |= valid;
updateCapabilities(oldScore, nai, nai.networkCapabilities);
// If score has changed, rebroadcast to NetworkFactories. b/17726566
if (oldScore != nai.getCurrentScore()) sendUpdatedScoreToFactories(nai);
}
updateInetCondition(nai);
// Let the NetworkAgent know the state of its network
Bundle redirectUrlBundle = new Bundle();
redirectUrlBundle.putString(NetworkAgent.REDIRECT_URL_KEY, redirectUrl);
nai.asyncChannel.sendMessage(
NetworkAgent.CMD_REPORT_NETWORK_STATUS,
(valid ? NetworkAgent.VALID_NETWORK : NetworkAgent.INVALID_NETWORK),
0, redirectUrlBundle);
if (wasValidated && !nai.lastValidated) {
handleNetworkUnvalidated(nai);
}
break;
}
Expand Down Expand Up @@ -2155,6 +2189,21 @@ private boolean maybeHandleNetworkMonitorMessage(Message msg) {
}
break;
}
case NetworkMonitor.EVENT_PRIVATE_DNS_CONFIG_RESOLVED: {
final NetworkAgentInfo nai;
synchronized (mNetworkForNetId) {
nai = mNetworkForNetId.get(msg.arg2);
}
if (nai == null) break;

final PrivateDnsConfig cfg = (PrivateDnsConfig) msg.obj;
final boolean reevaluationRequired = updatePrivateDns(nai, cfg);
if (nai.lastValidated && reevaluationRequired) {
nai.networkMonitor.sendMessage(
NetworkMonitor.CMD_FORCE_REEVALUATION, Process.SYSTEM_UID);
}
break;
}
}
return true;
}
Expand Down Expand Up @@ -2190,6 +2239,63 @@ public void handleMessage(Message msg) {
}
}

private void handlePrivateDnsSettingsChanged() {
final PrivateDnsConfig cfg = mDnsManager.getPrivateDnsConfig();

for (NetworkAgentInfo nai : mNetworkAgentInfos.values()) {
// Private DNS only ever applies to networks that might provide
// Internet access and therefore also require validation.
if (!NetworkMonitor.isValidationRequired(
mDefaultRequest.networkCapabilities, nai.networkCapabilities)) {
continue;
}

// Notify the NetworkMonitor thread in case it needs to cancel or
// schedule DNS resolutions. If a DNS resolution is required the
// result will be sent back to us.
nai.networkMonitor.notifyPrivateDnsSettingsChanged(cfg);

if (!cfg.inStrictMode()) {
// No strict mode hostname DNS resolution needed, so just update
// DNS settings directly. In opportunistic and "off" modes this
// just reprograms netd with the network-supplied DNS servers
// (and of course the boolean of whether or not to attempt TLS).
//
// TODO: Consider code flow parity with strict mode, i.e. having
// NetworkMonitor relay the PrivateDnsConfig back to us and then
// performing this call at that time.
updatePrivateDns(nai, cfg);
}
}
}

private boolean updatePrivateDns(NetworkAgentInfo nai, PrivateDnsConfig newCfg) {
final boolean reevaluationRequired = true;
final boolean dontReevaluate = false;

final PrivateDnsConfig oldCfg = mDnsManager.updatePrivateDns(nai.network, newCfg);
updateDnses(nai.linkProperties, null, nai.network.netId);

if (newCfg == null) {
if (oldCfg == null) return dontReevaluate;
return oldCfg.useTls ? reevaluationRequired : dontReevaluate;
}

if (oldCfg == null) {
return newCfg.useTls ? reevaluationRequired : dontReevaluate;
}

if (oldCfg.useTls != newCfg.useTls) {
return reevaluationRequired;
}

if (newCfg.inStrictMode() && !Objects.equals(oldCfg.hostname, newCfg.hostname)) {
return reevaluationRequired;
}

return dontReevaluate;
}

private void updateLingerState(NetworkAgentInfo nai, long now) {
// 1. Update the linger timer. If it's changed, reschedule or cancel the alarm.
// 2. If the network was lingering and there are now requests, unlinger it.
Expand Down Expand Up @@ -2324,6 +2430,7 @@ private void handleAsyncChannelDisconnected(Message msg) {
} catch (Exception e) {
loge("Exception removing network: " + e);
}
mDnsManager.removeNetwork(nai.network);
}
synchronized (mNetworkForNetId) {
mNetIdInUse.delete(nai.network.netId);
Expand Down Expand Up @@ -2870,6 +2977,9 @@ public void handleMessage(Message msg) {
handleReportNetworkConnectivity((Network) msg.obj, msg.arg1, toBool(msg.arg2));
break;
}
case EVENT_PRIVATE_DNS_SETTINGS_CHANGED:
handlePrivateDnsSettingsChanged();
break;
}
}
}
Expand Down Expand Up @@ -4559,11 +4669,12 @@ private void updateDnses(LinkProperties newLp, LinkProperties oldLp, int netId)
final NetworkAgentInfo defaultNai = getDefaultNetwork();
final boolean isDefaultNetwork = (defaultNai != null && defaultNai.network.netId == netId);

Collection<InetAddress> dnses = newLp.getDnsServers();
if (DBG) log("Setting DNS servers for network " + netId + " to " + dnses);
if (DBG) {
final Collection<InetAddress> dnses = newLp.getDnsServers();
log("Setting DNS servers for network " + netId + " to " + dnses);
}
try {
mDnsManager.setDnsConfigurationForNetwork(
netId, dnses, newLp.getDomains(), isDefaultNetwork);
mDnsManager.setDnsConfigurationForNetwork(netId, newLp, isDefaultNetwork);
} catch (Exception e) {
loge("Exception in setDnsConfigurationForNetwork: " + e);
}
Expand Down
12 changes: 0 additions & 12 deletions services/core/java/com/android/server/NetworkManagementService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,9 +21,6 @@
import static android.Manifest.permission.NETWORK_SETTINGS;
import static android.Manifest.permission.NETWORK_STACK;
import static android.Manifest.permission.SHUTDOWN;
import static android.net.ConnectivityManager.PRIVATE_DNS_DEFAULT_MODE;
import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_OPPORTUNISTIC;
import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
import static android.net.NetworkPolicyManager.FIREWALL_CHAIN_DOZABLE;
import static android.net.NetworkPolicyManager.FIREWALL_CHAIN_NAME_DOZABLE;
import static android.net.NetworkPolicyManager.FIREWALL_CHAIN_NAME_NONE;
Expand Down Expand Up @@ -1957,15 +1954,6 @@ public void setDnsConfigurationForNetwork(int netId, String[] servers, String[]
}
}

private static boolean shouldUseTls(ContentResolver cr) {
String privateDns = Settings.Global.getString(cr, Settings.Global.PRIVATE_DNS_MODE);
if (TextUtils.isEmpty(privateDns)) {
privateDns = PRIVATE_DNS_DEFAULT_MODE;
}
return privateDns.equals(PRIVATE_DNS_MODE_OPPORTUNISTIC) ||
privateDns.startsWith(PRIVATE_DNS_MODE_PROVIDER_HOSTNAME);
}

@Override
public void addVpnUidRanges(int netId, UidRange[] ranges) {
mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
Expand Down
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