Clean up DnsTlsDispatcher when a network is disconnected am: b46f8fae6f (70a21cad) · Commits · e / os / android_packages_modules_DnsResolver

DnsTlsDispatcher.cpp

+21 −4

Original line number	Diff line number	Diff line
		@@ -172,7 +172,7 @@ DnsTlsTransport::Response DnsTlsDispatcher::query(const DnsTlsServer& server, un
		{
		std::lock_guard guard(sLock);
		if (xport = getTransport(key); xport == nullptr) {
		xport = addTransport(server, mark);
		xport = addTransport(server, mark, netId);
		}
		++xport->useCount;
		}
		@@ -226,6 +226,11 @@ DnsTlsTransport::Response DnsTlsDispatcher::query(const DnsTlsServer& server, un
		return code;
		}

		void DnsTlsDispatcher::forceCleanup(unsigned netId) {
		std::lock_guard guard(sLock);
		forceCleanupLocked(netId);
		}

		DnsTlsTransport::Result DnsTlsDispatcher::queryInternal(Transport& xport,
		const netdutils::Slice query) {
		LOG(DEBUG) << "Sending query of length " << query.size();
		@@ -272,8 +277,20 @@ void DnsTlsDispatcher::cleanup(std::chrono::time_point<std::chrono::steady_clock
		mLastCleanup = now;
		}

		// TODO: unify forceCleanupLocked() and cleanup().
		void DnsTlsDispatcher::forceCleanupLocked(unsigned netId) {
		for (auto it = mStore.begin(); it != mStore.end();) {
		auto& s = it->second;
		if (s->useCount == 0 && s->mNetId == netId) {
		it = mStore.erase(it);
		} else {
		++it;
		}
		}
		}

		DnsTlsDispatcher::Transport* DnsTlsDispatcher::addTransport(const DnsTlsServer& server,
		unsigned mark) {
		unsigned mark, unsigned netId) {
		const Key key = std::make_pair(mark, server);
		Transport* ret = getTransport(key);
		if (ret != nullptr) return ret;
		@@ -300,8 +317,8 @@ DnsTlsDispatcher::Transport* DnsTlsDispatcher::addTransport(const DnsTlsServer&
		queryTimeout = 1000;
		}

		ret = new Transport(server, mark, mFactory.get(), revalidationEnabled, triggerThr, unusableThr,
		queryTimeout);
		ret = new Transport(server, mark, netId, mFactory.get(), revalidationEnabled, triggerThr,
		unusableThr, queryTimeout);
		LOG(DEBUG) << "Transport is initialized with { " << triggerThr << ", " << unusableThr << ", "
		<< queryTimeout << "ms }"
		<< " for server { " << server.toIpString() << "/" << server.name << " }";

DnsTlsDispatcher.h

+16 −3

Original line number	Diff line number	Diff line
		@@ -65,6 +65,8 @@ class DnsTlsDispatcher : public PrivateDnsValidationObserver {
		// Implement PrivateDnsValidationObserver.
		void onValidationStateUpdate(const std::string&, Validation, uint32_t) override{};

		void forceCleanup(unsigned netId) EXCLUDES(sLock);

		private:
		DnsTlsDispatcher();

		@@ -79,15 +81,22 @@ class DnsTlsDispatcher : public PrivateDnsValidationObserver {
		// Transport is a thin wrapper around DnsTlsTransport, adding reference counting and
		// usage monitoring so we can expire idle sessions from the cache.
		struct Transport {
		Transport(const DnsTlsServer& server, unsigned mark, IDnsTlsSocketFactory* _Nonnull factory,
		bool revalidationEnabled, int triggerThr, int unusableThr, int timeout)
		Transport(const DnsTlsServer& server, unsigned mark, unsigned netId,
		IDnsTlsSocketFactory* _Nonnull factory, bool revalidationEnabled, int triggerThr,
		int unusableThr, int timeout)
		: transport(server, mark, factory),
		mNetId(netId),
		revalidationEnabled(revalidationEnabled),
		triggerThreshold(triggerThr),
		unusableThreshold(unusableThr),
		mTimeout(timeout) {}

		// DnsTlsTransport is thread-safe, so it doesn't need to be guarded.
		DnsTlsTransport transport;

		// The expected network, assigned from dns_netid, to which Transport will send DNS packets.
		const unsigned mNetId;

		// This use counter and timestamp are used to ensure that only idle sessions are
		// destroyed.
		int useCount GUARDED_BY(sLock) = 0;
		@@ -134,7 +143,8 @@ class DnsTlsDispatcher : public PrivateDnsValidationObserver {
		const std::chrono::milliseconds mTimeout;
		};

		Transport* _Nullable addTransport(const DnsTlsServer& server, unsigned mark) REQUIRES(sLock);
		Transport* _Nullable addTransport(const DnsTlsServer& server, unsigned mark, unsigned netId)
		REQUIRES(sLock);
		Transport* _Nullable getTransport(const Key& key) REQUIRES(sLock);

		// Cache of reusable DnsTlsTransports. Transports stay in cache as long as
		@@ -152,6 +162,9 @@ class DnsTlsDispatcher : public PrivateDnsValidationObserver {
		// This function performs a linear scan of mStore.
		void cleanup(std::chrono::time_point<std::chrono::steady_clock> now) REQUIRES(sLock);

		// Force dropping any Transports whose useCount is zero.
		void forceCleanupLocked(unsigned netId) REQUIRES(sLock);

		// Return a sorted list of usable DnsTlsServers in preference order.
		std::list<DnsTlsServer> getOrderedAndUsableServerList(const std::list<DnsTlsServer>& tlsServers,
		unsigned netId, unsigned mark);

ResolverController.cpp

+4 −0

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@

		#include "Dns64Configuration.h"
		#include "DnsResolver.h"
		#include "DnsTlsDispatcher.h"
		#include "PrivateDnsConfiguration.h"
		#include "ResolverEventReporter.h"
		#include "ResolverStats.h"
		@@ -166,6 +167,9 @@ void ResolverController::destroyNetworkCache(unsigned netId) {
		resolv_delete_cache_for_net(netId);
		mDns64Configuration.stopPrefixDiscovery(netId);
		PrivateDnsConfiguration::getInstance().clear(netId);

		// Don't get this instance in PrivateDnsConfiguration. It's probe to deadlock.
		DnsTlsDispatcher::getInstance().forceCleanup(netId);
		}

		int ResolverController::createNetworkCache(unsigned netId) {