Implement proper discovery with subtypes
Apps may want to discover a particular subtype, such as _color._sub._printer._tcp.local, which may return services like Printer1._printer._tcp.local. The previous code was trying to discover, and would return service types named _color._sub._printer._tcp.local, even though the actual service type is still _printer._tcp.local. This is a regression compared to S/T. Fix this by passing the subtype to MdnsDiscoveryManager in its options instead of the service type, and ensure that MdnsDiscoveryManager only sends callbacks to callers that have requested the given subtype (a color that asked for _color._sub._printer._tcp.local should not receive BlackAndWhite._printer._tcp.local). Bug: 266167702 Test: atest Change-Id: I21367c66534078667718a9b54dfc858b12ba7103
This commit is contained in:
Remi NGUYEN VAN
@@ -55,6 +55,7 @@ import android.os.RemoteException;
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import android.os.UserHandle;
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import android.text.TextUtils;
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import android.util.Log;
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import android.util.Pair;
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import android.util.SparseArray;
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import com.android.internal.annotations.VisibleForTesting;
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@@ -599,7 +600,10 @@ public class NsdService extends INsdManager.Stub {
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final NsdServiceInfo info = args.serviceInfo;
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id = getUniqueId();
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final String serviceType = constructServiceType(info.getServiceType());
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final Pair<String, String> typeAndSubtype =
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parseTypeAndSubtype(info.getServiceType());
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final String serviceType = typeAndSubtype == null
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? null : typeAndSubtype.first;
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if (clientInfo.mUseJavaBackend
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|| mDeps.isMdnsDiscoveryManagerEnabled(mContext)
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|| useDiscoveryManagerForType(serviceType)) {
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@@ -613,12 +617,17 @@ public class NsdService extends INsdManager.Stub {
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maybeStartMonitoringSockets();
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final MdnsListener listener =
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new DiscoveryListener(clientId, id, info, listenServiceType);
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final MdnsSearchOptions options = MdnsSearchOptions.newBuilder()
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.setNetwork(info.getNetwork())
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.setIsPassiveMode(true)
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.build();
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final MdnsSearchOptions.Builder optionsBuilder =
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MdnsSearchOptions.newBuilder()
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.setNetwork(info.getNetwork())
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.setIsPassiveMode(true);
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if (typeAndSubtype.second != null) {
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// The parsing ensures subtype starts with an underscore.
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// MdnsSearchOptions expects the underscore to not be present.
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optionsBuilder.addSubtype(typeAndSubtype.second.substring(1));
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}
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mMdnsDiscoveryManager.registerListener(
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listenServiceType, listener, options);
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listenServiceType, listener, optionsBuilder.build());
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storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo);
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clientInfo.onDiscoverServicesStarted(clientId, info);
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clientInfo.log("Register a DiscoveryListener " + id
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@@ -697,7 +706,9 @@ public class NsdService extends INsdManager.Stub {
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id = getUniqueId();
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final NsdServiceInfo serviceInfo = args.serviceInfo;
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final String serviceType = serviceInfo.getServiceType();
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final String registerServiceType = constructServiceType(serviceType);
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final Pair<String, String> typeSubtype = parseTypeAndSubtype(serviceType);
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final String registerServiceType = typeSubtype == null
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? null : typeSubtype.first;
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if (clientInfo.mUseJavaBackend
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|| mDeps.isMdnsAdvertiserEnabled(mContext)
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|| useAdvertiserForType(registerServiceType)) {
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@@ -712,6 +723,10 @@ public class NsdService extends INsdManager.Stub {
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serviceInfo.getServiceName()));
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maybeStartMonitoringSockets();
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// TODO: pass in the subtype as well. Including the subtype in the
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// service type would generate service instance names like
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// Name._subtype._sub._type._tcp, which is incorrect
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// (it should be Name._type._tcp).
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mAdvertiser.addService(id, serviceInfo);
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storeAdvertiserRequestMap(clientId, id, clientInfo);
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} else {
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@@ -778,7 +793,10 @@ public class NsdService extends INsdManager.Stub {
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final NsdServiceInfo info = args.serviceInfo;
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id = getUniqueId();
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final String serviceType = constructServiceType(info.getServiceType());
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final Pair<String, String> typeSubtype =
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parseTypeAndSubtype(info.getServiceType());
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final String serviceType = typeSubtype == null
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? null : typeSubtype.first;
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if (clientInfo.mUseJavaBackend
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|| mDeps.isMdnsDiscoveryManagerEnabled(mContext)
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|| useDiscoveryManagerForType(serviceType)) {
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@@ -871,7 +889,10 @@ public class NsdService extends INsdManager.Stub {
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final NsdServiceInfo info = args.serviceInfo;
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id = getUniqueId();
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final String serviceType = constructServiceType(info.getServiceType());
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final Pair<String, String> typeAndSubtype =
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parseTypeAndSubtype(info.getServiceType());
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final String serviceType = typeAndSubtype == null
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? null : typeAndSubtype.first;
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if (serviceType == null) {
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clientInfo.onServiceInfoCallbackRegistrationFailed(clientId,
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NsdManager.FAILURE_BAD_PARAMETERS);
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@@ -1315,28 +1336,39 @@ public class NsdService extends INsdManager.Stub {
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* Check the given service type is valid and construct it to a service type
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* which can use for discovery / resolution service.
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*
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* <p> The valid service type should be 2 labels, or 3 labels if the query is for a
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* <p>The valid service type should be 2 labels, or 3 labels if the query is for a
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* subtype (see RFC6763 7.1). Each label is up to 63 characters and must start with an
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* underscore; they are alphanumerical characters or dashes or underscore, except the
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* last one that is just alphanumerical. The last label must be _tcp or _udp.
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*
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* <p>The subtype may also be specified with a comma after the service type, for example
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* _type._tcp,_subtype.
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*
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* @param serviceType the request service type for discovery / resolution service
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* @return constructed service type or null if the given service type is invalid.
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*/
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@Nullable
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public static String constructServiceType(String serviceType) {
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public static Pair<String, String> parseTypeAndSubtype(String serviceType) {
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if (TextUtils.isEmpty(serviceType)) return null;
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final String typeOrSubtypePattern = "_[a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]";
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final Pattern serviceTypePattern = Pattern.compile(
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"^(_[a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]\\.)?"
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+ "(_[a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]\\._(?:tcp|udp))"
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// Optional leading subtype (_subtype._type._tcp)
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// (?: xxx) is a non-capturing parenthesis, don't capture the dot
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"^(?:(" + typeOrSubtypePattern + ")\\.)?"
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// Actual type (_type._tcp.local)
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+ "(" + typeOrSubtypePattern + "\\._(?:tcp|udp))"
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// Drop '.' at the end of service type that is compatible with old backend.
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+ "\\.?$");
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// e.g. allow "_type._tcp.local."
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+ "\\.?"
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// Optional subtype after comma, for "_type._tcp,_subtype" format
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+ "(?:,(" + typeOrSubtypePattern + "))?"
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+ "$");
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final Matcher matcher = serviceTypePattern.matcher(serviceType);
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if (!matcher.matches()) return null;
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return matcher.group(1) == null
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? matcher.group(2)
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: matcher.group(1) + "_sub." + matcher.group(2);
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// Use the subtype either at the beginning or after the comma
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final String subtype = matcher.group(1) != null ? matcher.group(1) : matcher.group(3);
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return new Pair<>(matcher.group(2), subtype);
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}
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@VisibleForTesting
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