Merge "Remove validation threads tracking in PrivateDnsConfiguration" (2eece3f5) · Commits · e / os / android_packages_modules_DnsResolver

DnsTlsServer.h

+14 −1

Original line number	Diff line number	Diff line
		@@ -28,7 +28,14 @@ namespace android {
		namespace net {

		// Validation status of a DNS over TLS server (on a specific netId).
		enum class Validation : uint8_t { in_process, success, fail, unknown_server, unknown_netid };
		enum class Validation : uint8_t {
		in_process,
		success,
		success_but_expired,
		fail,
		unknown_server,
		unknown_netid,
		};

		// DnsTlsServer represents a recursive resolver that supports, or may support, a
		// secure protocol.
		@@ -66,9 +73,15 @@ struct DnsTlsServer {
		Validation validationState() const { return mValidation; }
		void setValidationState(Validation val) { mValidation = val; }

		// Return whether or not the server can be used for a network. It depends on
		// the resolver configuration.
		bool active() const { return mActive; }
		void setActive(bool val) { mActive = val; }

		private:
		// State, unrelated to the comparison of DnsTlsServer objects.
		Validation mValidation = Validation::unknown_server;
		bool mActive = false;
		};

		// This comparison only checks the IP address. It ignores ports, names, and fingerprints.

PrivateDnsConfiguration.cpp

+37 −97

Original line number	Diff line number	Diff line
		@@ -89,61 +89,30 @@ int PrivateDnsConfiguration::set(int32_t netId, uint32_t mark,
		} else {
		mPrivateDnsModes[netId] = PrivateDnsMode::OFF;
		mPrivateDnsTransports.erase(netId);
		mPrivateDnsValidateThreads.erase(netId);
		// TODO: As mPrivateDnsValidateThreads is reset, validation threads which haven't yet
		// finished are considered outdated. Consider signaling the outdated validation threads to
		// stop them from updating the state of PrivateDnsConfiguration (possibly disallow them to
		// report onPrivateDnsValidationEvent).
		// TODO: signal validation threads to stop.
		return 0;
		}

		// Create the tracker if it was not present
		auto netPair = mPrivateDnsTransports.find(netId);
		if (netPair == mPrivateDnsTransports.end()) {
		// No TLS tracker yet for this netId.
		bool added;
		std::tie(netPair, added) = mPrivateDnsTransports.emplace(netId, PrivateDnsTracker());
		if (!added) {
		LOG(ERROR) << "Memory error while recording private DNS for netId " << netId;
		return -ENOMEM;
		}
		}
		auto& tracker = netPair->second;

		// Remove any servers from the tracker that are not in \|servers\| exactly.
		for (auto it = tracker.begin(); it != tracker.end();) {
		if (tmp.find(it->first) == tmp.end()) {
		it = tracker.erase(it);
		} else {
		++it;
		}
		}
		auto& tracker = mPrivateDnsTransports[netId];

		// Add any new or changed servers to the tracker, and initiate async checks for them.
		// Add the servers if not contained in tracker.
		for (const auto& [identity, server] : tmp) {
		if (needsValidation(tracker, server)) {
		// This is temporarily required. Consider the following scenario, for example,
		// Step 1) A DoTServer (s1) is set for the network. A validation (v1) for s1 starts.
		// tracker has s1 alone.
		// Step 2) The configuration changes. DotServer2 (s2) is set for the network. A
		// validation (v2) for s2 starts. tracker has s2 alone.
		// Step 3) Assume v1 and v2 somehow block. Now, if the configuration changes back to
		// set s1, there won't be a v1' starts because needValidateThread() will
		// return false.
		//
		// If we didn't add servers to tracker before needValidateThread(), tracker would
		// become empty. We would report s1 validation failed.
		if (tracker.find(identity) == tracker.end()) {
		tracker[identity] = server;
		}
		tracker[identity].setValidationState(Validation::in_process);
		LOG(DEBUG) << "Server " << addrToString(&server.ss) << " marked as in_process on netId "
		<< netId << ". Tracker now has size " << tracker.size();
		// This judge must be after "tracker[server] = Validation::in_process;"
		if (!needValidateThread(server, netId)) {
		continue;
		}

		for (auto& [identity, server] : tracker) {
		const bool active = tmp.find(identity) != tmp.end();
		server.setActive(active);

		// For simplicity, deem the validation result of inactive servers as unreliable.
		if (!server.active() && server.validationState() == Validation::success) {
		updateServerState(identity, Validation::success_but_expired, netId);
		}

		if (needsValidation(server)) {
		updateServerState(identity, Validation::in_process, netId);
		startValidation(server, netId, mark);
		}
		@@ -163,9 +132,11 @@ PrivateDnsStatus PrivateDnsConfiguration::getStatus(unsigned netId) {
		const auto netPair = mPrivateDnsTransports.find(netId);
		if (netPair != mPrivateDnsTransports.end()) {
		for (const auto& [_, server] : netPair->second) {
		if (server.active()) {
		status.serversMap.emplace(server, server.validationState());
		}
		}
		}

		return status;
		}
		@@ -175,7 +146,6 @@ void PrivateDnsConfiguration::clear(unsigned netId) {
		std::lock_guard guard(mPrivateDnsLock);
		mPrivateDnsModes.erase(netId);
		mPrivateDnsTransports.erase(netId);
		mPrivateDnsValidateThreads.erase(netId);
		}

		void PrivateDnsConfiguration::startValidation(const DnsTlsServer& server, unsigned netId,
		@@ -216,12 +186,12 @@ void PrivateDnsConfiguration::startValidation(const DnsTlsServer& server, unsign
		}

		if (backoff.hasNextTimeout()) {
		// TODO: make the thread able to receive signals to shutdown early.
		std::this_thread::sleep_for(backoff.getNextTimeout());
		} else {
		break;
		}
		}
		this->cleanValidateThreadTracker(server, netId);
		});
		validate_thread.detach();
		}
		@@ -266,6 +236,11 @@ bool PrivateDnsConfiguration::recordPrivateDnsValidation(const DnsTlsServer& ser
		<< " was changed during private DNS validation";
		success = false;
		reevaluationStatus = DONT_REEVALUATE;
		} else if (!serverPair->second.active()) {
		LOG(WARNING) << "Server " << addrToString(&server.ss)
		<< " was removed from the configuration";
		success = false;
		reevaluationStatus = DONT_REEVALUATE;
		}

		// Send a validation event to NetdEventListenerService.
		@@ -297,34 +272,6 @@ bool PrivateDnsConfiguration::recordPrivateDnsValidation(const DnsTlsServer& ser
		return reevaluationStatus;
		}

		bool PrivateDnsConfiguration::needValidateThread(const DnsTlsServer& server, unsigned netId)
		REQUIRES(mPrivateDnsLock) {
		// Create the thread tracker if it was not present
		auto threadPair = mPrivateDnsValidateThreads.find(netId);
		if (threadPair == mPrivateDnsValidateThreads.end()) {
		// No thread tracker yet for this netId.
		bool added;
		std::tie(threadPair, added) = mPrivateDnsValidateThreads.emplace(netId, ThreadTracker());
		if (!added) {
		LOG(ERROR) << "Memory error while needValidateThread for netId " << netId;
		return true;
		}
		}
		auto& threadTracker = threadPair->second;
		if (threadTracker.count(server)) {
		LOG(DEBUG) << "Server " << addrToString(&(server.ss))
		<< " validate thread is already running. Thread tracker now has size "
		<< threadTracker.size();
		return false;
		} else {
		threadTracker.insert(server);
		LOG(DEBUG) << "Server " << addrToString(&(server.ss))
		<< " validate thread is not running. Thread tracker now has size "
		<< threadTracker.size();
		return true;
		}
		}

		void PrivateDnsConfiguration::updateServerState(const ServerIdentity& identity, Validation state,
		uint32_t netId) {
		auto netPair = mPrivateDnsTransports.find(netId);
		@@ -343,27 +290,20 @@ void PrivateDnsConfiguration::updateServerState(const ServerIdentity& identity,
		maybeNotifyObserver(identity.ip.toString(), state, netId);
		}

		void PrivateDnsConfiguration::cleanValidateThreadTracker(const DnsTlsServer& server,
		unsigned netId) {
		std::lock_guard<std::mutex> guard(mPrivateDnsLock);
		LOG(DEBUG) << "cleanValidateThreadTracker Server " << addrToString(&(server.ss))
		<< " validate thread is stopped.";
		bool PrivateDnsConfiguration::needsValidation(const DnsTlsServer& server) {
		// The server is not expected to be used on the network.
		if (!server.active()) return false;

		auto threadPair = mPrivateDnsValidateThreads.find(netId);
		if (threadPair != mPrivateDnsValidateThreads.end()) {
		auto& threadTracker = threadPair->second;
		threadTracker.erase(server);
		LOG(DEBUG) << "Server " << addrToString(&(server.ss))
		<< " validate thread is stopped. Thread tracker now has size "
		<< threadTracker.size();
		}
		}
		// The server is newly added.
		if (server.validationState() == Validation::unknown_server) return true;

		bool PrivateDnsConfiguration::needsValidation(const PrivateDnsTracker& tracker,
		const DnsTlsServer& server) {
		const ServerIdentity identity = ServerIdentity(server);
		const auto& iter = tracker.find(identity);
		return (iter == tracker.end()) \|\| (iter->second.validationState() == Validation::fail);
		// The server has failed at least one validation attempt. Give it another try.
		if (server.validationState() == Validation::fail) return true;

		// The previous validation result might be unreliable.
		if (server.validationState() == Validation::success_but_expired) return true;

		return false;
		}

		void PrivateDnsConfiguration::setObserver(Observer* observer) {

PrivateDnsConfiguration.h

+7 −11

Original line number	Diff line number	Diff line
		@@ -95,26 +95,22 @@ class PrivateDnsConfiguration {
		bool recordPrivateDnsValidation(const DnsTlsServer& server, unsigned netId, bool success)
		EXCLUDES(mPrivateDnsLock);

		bool needValidateThread(const DnsTlsServer& server, unsigned netId) REQUIRES(mPrivateDnsLock);
		void cleanValidateThreadTracker(const DnsTlsServer& server, unsigned netId)
		EXCLUDES(mPrivateDnsLock);

		// Start validation for newly added servers as well as any servers that have
		// landed in Validation::fail state. Note that servers that have failed
		// Decide if a validation for \|server\| is needed. Note that servers that have failed
		// multiple validation attempts but for which there is still a validating
		// thread running are marked as being Validation::in_process.
		bool needsValidation(const PrivateDnsTracker& tracker, const DnsTlsServer& server)
		REQUIRES(mPrivateDnsLock);
		bool needsValidation(const DnsTlsServer& server) REQUIRES(mPrivateDnsLock);

		void updateServerState(const ServerIdentity& identity, Validation state, uint32_t netId)
		REQUIRES(mPrivateDnsLock);

		std::mutex mPrivateDnsLock;
		std::map<unsigned, PrivateDnsMode> mPrivateDnsModes GUARDED_BY(mPrivateDnsLock);
		// Structure for tracking the validation status of servers on a specific netId.
		// Using the AddressComparator ensures at most one entry per IP address.

		// Contains all servers for a network, along with their current validation status.
		// In case a server is removed due to a configuration change, it remains in this map,
		// but is marked inactive.
		// Any pending validation threads will continue running because we have no way to cancel them.
		std::map<unsigned, PrivateDnsTracker> mPrivateDnsTransports GUARDED_BY(mPrivateDnsLock);
		std::map<unsigned, ThreadTracker> mPrivateDnsValidateThreads GUARDED_BY(mPrivateDnsLock);

		// For testing. The observer is notified of onValidationStateUpdate 1) when a validation is
		// about to begin or 2) when a validation finishes. If a validation finishes when in OFF mode

ResolverController.cpp

+2 −0

Original line number	Diff line number	Diff line
		@@ -70,6 +70,8 @@ constexpr const char* validationStatusToString(Validation value) {
		return "in_process";
		case Validation::success:
		return "success";
		case Validation::success_but_expired:
		return "success_but_expired";
		case Validation::fail:
		return "fail";
		case Validation::unknown_server:

resolv_tls_unit_test.cpp

+6 −0

Original line number	Diff line number	Diff line
		@@ -892,9 +892,15 @@ TEST_F(ServerTest, State) {
		checkEqual(s1, s2);
		s2.setValidationState(Validation::fail);
		checkEqual(s1, s2);
		s1.setActive(true);
		checkEqual(s1, s2);
		s2.setActive(false);
		checkEqual(s1, s2);

		EXPECT_EQ(s1.validationState(), Validation::success);
		EXPECT_EQ(s2.validationState(), Validation::fail);
		EXPECT_TRUE(s1.active());
		EXPECT_FALSE(s2.active());
		}

		TEST(QueryMapTest, Basic) {