Replace evdns with getaddrinfo and getnameinfo (#3766)

src/OSSupport/CMakeLists.txt

@@ -12,6 +12,7 @@ SET (SRCS
 	IPLookup.cpp
 	IsThread.cpp
 	NetworkInterfaceEnum.cpp
+	NetworkLookup.cpp
 	NetworkSingleton.cpp
 	ServerHandleImpl.cpp
 	StackTrace.cpp
@@ -24,11 +25,13 @@ SET (HDRS
 	Errors.h
 	Event.h
 	File.h
+	GetAddressInfoError.h
 	GZipFile.h
 	HostnameLookup.h
 	IPLookup.h
 	IsThread.h
 	Network.h
+	NetworkLookup.h
 	NetworkSingleton.h
 	Queue.h
 	ServerHandleImpl.h

src/OSSupport/GetAddressInfoError.h

@@ -0,0 +1,29 @@
+#pragma once
+
+
+
+/** Returns the readable form of a getaddressinfo type error code */
+inline AString ErrorString(int a_ErrorCode)
+{
+	// Note gai_strerror is not threadsafe on windows
+	#ifdef _WIN32
+		char ErrorStr[GAI_STRERROR_BUFFER_SIZE + 1];
+
+		int MsgLen = FormatMessageA(
+			FORMAT_MESSAGE_FROM_SYSTEM |
+			FORMAT_MESSAGE_IGNORE_INSERTS |
+			FORMAT_MESSAGE_MAX_WIDTH_MASK,
+			nullptr,
+			a_ErrorCode,
+			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+			ErrorStr,
+			sizeof(ErrorStr) - 1,
+			nullptr
+		);
+
+		return AString(ErrorStr, MsgLen);
+	#else
+		return gai_strerror(a_ErrorCode);
+	#endif
+}
+

src/OSSupport/HostnameLookup.cpp

@@ -5,8 +5,8 @@
 
 #include "Globals.h"
 #include "HostnameLookup.h"
-#include <event2/dns.h>
 #include "NetworkSingleton.h"
+#include "GetAddressInfoError.h"
 
 
 
@@ -15,8 +15,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 // cHostnameLookup:
 
-cHostnameLookup::cHostnameLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
+cHostnameLookup::cHostnameLookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks):
-	m_Callbacks(a_Callbacks)
+	m_Callbacks(a_Callbacks),
+	m_Hostname(a_Hostname)
 {
 }
 
@@ -24,43 +25,45 @@ cHostnameLookup::cHostnameLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks)
 
 
 
-void cHostnameLookup::Lookup(const AString & a_Hostname)
+void cHostnameLookup::Lookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks)
 {
-	// Store the hostname for the callback:
+	// Cannot use std::make_shared here, constructor is not accessible
-	m_Hostname = a_Hostname;
+	cHostnameLookupPtr Lookup{ new cHostnameLookup(a_Hostname, std::move(a_Callbacks)) };
 
-	// Start the lookup:
+	// Note the Lookup object is owned solely by this lambda which is destroyed after it runs
-	// Note that we don't have to store the LibEvent lookup handle, LibEvent will free it on its own.
+	cNetworkSingleton::Get().GetLookupThread().ScheduleLookup([=]()
-	evutil_addrinfo hints;
+	{
-	memset(&hints, 0, sizeof(hints));
+		// Start the lookup:
-	hints.ai_protocol = IPPROTO_TCP;
+		addrinfo hints;
-	hints.ai_socktype = SOCK_STREAM;
+		memset(&hints, 0, sizeof(hints));
-	hints.ai_family = AF_UNSPEC;
+		hints.ai_protocol = IPPROTO_TCP;
-	hints.ai_flags = EVUTIL_AI_CANONNAME;
+		hints.ai_socktype = SOCK_STREAM;
-	evdns_getaddrinfo(cNetworkSingleton::Get().GetDNSBase(), a_Hostname.c_str(), nullptr, &hints, Callback, this);
+		hints.ai_family = AF_UNSPEC;
+		hints.ai_flags = AI_CANONNAME;
+
+		addrinfo * Result;
+		int ErrCode = getaddrinfo(Lookup->m_Hostname.c_str(), nullptr, &hints, &Result);
+
+		Lookup->Callback(ErrCode, Result);
+	});
 }
 
 
 
 
 
-void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a_Self)
+void cHostnameLookup::Callback(int a_ErrCode, addrinfo * a_Addr)
 {
-	// Get the Self class:
-	cHostnameLookup * Self = reinterpret_cast<cHostnameLookup *>(a_Self);
-	ASSERT(Self != nullptr);
-
 	// If an error has occurred, notify the error callback:
 	if (a_ErrCode != 0)
 	{
-		Self->m_Callbacks->OnError(a_ErrCode, evutil_socket_error_to_string(a_ErrCode));
+		m_Callbacks->OnError(a_ErrCode, ErrorString(a_ErrCode));
-		cNetworkSingleton::Get().RemoveHostnameLookup(Self);
 		return;
 	}
 
 	// Call the success handler for each entry received:
 	bool HasResolved = false;
-	evutil_addrinfo * OrigAddr = a_Addr;
+	addrinfo * OrigAddr = a_Addr;
 	for (;a_Addr != nullptr; a_Addr = a_Addr->ai_next)
 	{
 		char IP[128];
@@ -69,7 +72,7 @@ void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a
 			case AF_INET:  // IPv4
 			{
 				sockaddr_in * sin = reinterpret_cast<sockaddr_in *>(a_Addr->ai_addr);
-				if (!Self->m_Callbacks->OnNameResolvedV4(Self->m_Hostname, sin))
+				if (!m_Callbacks->OnNameResolvedV4(m_Hostname, sin))
 				{
 					// Callback indicated that the IP shouldn't be serialized to a string, just continue with the next address:
 					HasResolved = true;
@@ -81,7 +84,7 @@ void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a
 			case AF_INET6:  // IPv6
 			{
 				sockaddr_in6 * sin = reinterpret_cast<sockaddr_in6 *>(a_Addr->ai_addr);
-				if (!Self->m_Callbacks->OnNameResolvedV6(Self->m_Hostname, sin))
+				if (!m_Callbacks->OnNameResolvedV6(m_Hostname, sin))
 				{
 					// Callback indicated that the IP shouldn't be serialized to a string, just continue with the next address:
 					HasResolved = true;
@@ -96,21 +99,20 @@ void cHostnameLookup::Callback(int a_ErrCode, evutil_addrinfo * a_Addr, void * a
 				continue;  // for (a_Addr)
 			}
 		}
-		Self->m_Callbacks->OnNameResolved(Self->m_Hostname, IP);
+		m_Callbacks->OnNameResolved(m_Hostname, IP);
 		HasResolved = true;
 	}  // for (a_Addr)
 
 	// If only unsupported families were reported, call the Error handler:
 	if (!HasResolved)
 	{
-		Self->m_Callbacks->OnError(DNS_ERR_NODATA, "The name does not resolve to any known address.");
+		m_Callbacks->OnError(EAI_NODATA, ErrorString(EAI_NODATA));
 	}
 	else
 	{
-		Self->m_Callbacks->OnFinished();
+		m_Callbacks->OnFinished();
 	}
-	evutil_freeaddrinfo(OrigAddr);
+	freeaddrinfo(OrigAddr);
-	cNetworkSingleton::Get().RemoveHostnameLookup(Self);
 }
 
 
@@ -125,9 +127,7 @@ bool cNetwork::HostnameToIP(
 	cNetwork::cResolveNameCallbacksPtr a_Callbacks
 )
 {
-	auto Lookup = std::make_shared<cHostnameLookup>(a_Callbacks);
+	cHostnameLookup::Lookup(a_Hostname, std::move(a_Callbacks));
-	cNetworkSingleton::Get().AddHostnameLookup(Lookup);
-	Lookup->Lookup(a_Hostname);
 	return true;
 }
 

src/OSSupport/HostnameLookup.h

@@ -12,7 +12,6 @@
 #pragma once
 
 #include "Network.h"
-#include <event2/util.h>
 
 
 
@@ -22,21 +21,21 @@
 class cHostnameLookup
 {
 public:
-	/** Creates the lookup object. Doesn't start the lookup yet. */
+	/** Creates a lookup object and schedules the lookup. */
-	cHostnameLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks);
+	static void Lookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
-
-	/** Starts the lookup. */
-	void Lookup(const AString & a_Hostname);
 
 protected:
 
+	/** Creates the lookup object. Doesn't start the lookup yet. */
+	cHostnameLookup(const AString & a_Hostname, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
+
 	/** The callbacks to call for resolved names / errors. */
 	cNetwork::cResolveNameCallbacksPtr m_Callbacks;
 
 	/** The hostname that was queried (needed for the callbacks). */
 	AString m_Hostname;
 
-	static void Callback(int a_ErrCode, struct evutil_addrinfo * a_Addr, void * a_Self);
+	void Callback(int a_ErrCode, struct addrinfo * a_Addr);
 };
 typedef SharedPtr<cHostnameLookup> cHostnameLookupPtr;
 typedef std::vector<cHostnameLookupPtr> cHostnameLookupPtrs;

src/OSSupport/IPLookup.cpp

@@ -5,8 +5,9 @@
 
 #include "Globals.h"
 #include "IPLookup.h"
-#include <event2/dns.h>
+#include <event2/util.h>
 #include "NetworkSingleton.h"
+#include "GetAddressInfoError.h"
 
 
 
@@ -15,8 +16,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 // cIPLookup:
 
-cIPLookup::cIPLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
+cIPLookup::cIPLookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks):
-	m_Callbacks(a_Callbacks)
+	m_Callbacks(a_Callbacks),
+	m_IP(a_IP)
 {
 	ASSERT(a_Callbacks != nullptr);
 }
@@ -25,68 +27,58 @@ cIPLookup::cIPLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks):
 
 
 
-bool cIPLookup::Lookup(const AString & a_IP)
+void cIPLookup::Lookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks)
 {
-	// Parse the IP address string into a sockaddr structure:
+	cIPLookupPtr Lookup{ new cIPLookup(a_IP, std::move(a_Callbacks)) };  // Cannot use std::make_shared here, constructor is not accessible
-	m_IP = a_IP;
-	sockaddr_storage sa;
-	int salen = static_cast<int>(sizeof(sa));
-	memset(&sa, 0, sizeof(sa));
-	if (evutil_parse_sockaddr_port(a_IP.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen) != 0)
-	{
-		LOGD("Failed to parse IP address \"%s\".", a_IP.c_str());
-		return false;
-	}
 
-	// Call the proper resolver based on the address family:
+	// Note the Lookup object is owned solely by this lambda which is destroyed after it runs
-	// Note that there's no need to store the evdns_request handle returned, LibEvent frees it on its own.
+	cNetworkSingleton::Get().GetLookupThread().ScheduleLookup([=]()
-	switch (sa.ss_family)
 	{
-		case AF_INET:
+		sockaddr_storage sa;
+		int salen = sizeof(sa);
+		memset(&sa, 0, sizeof(sa));
+
+		int ErrCode = evutil_parse_sockaddr_port(Lookup->m_IP.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen);
+
+		if (ErrCode != 0)
 		{
-			sockaddr_in * sa4 = reinterpret_cast<sockaddr_in *>(&sa);
+			LOGD("Failed to parse IP address \"%s\".", Lookup->m_IP.c_str());
-			evdns_base_resolve_reverse(cNetworkSingleton::Get().GetDNSBase(), &(sa4->sin_addr), 0, Callback, this);
+			Lookup->Callback(ErrCode, nullptr);
-			break;
+			return;
 		}
-		case AF_INET6:
+
-		{
+		char Hostname[NI_MAXHOST];
-			sockaddr_in6 * sa6 = reinterpret_cast<sockaddr_in6 *>(&sa);
+		char ServInfo[NI_MAXSERV];
-			evdns_base_resolve_reverse_ipv6(cNetworkSingleton::Get().GetDNSBase(), &(sa6->sin6_addr), 0, Callback, this);
+
-			break;
+		ErrCode = getnameinfo(
-		}
+			reinterpret_cast<sockaddr *>(&sa),
-		default:
+			static_cast<socklen_t>(salen),
-		{
+			Hostname, sizeof(Hostname),
-			LOGWARNING("%s: Unknown address family: %d", __FUNCTION__, sa.ss_family);
+			ServInfo, sizeof(ServInfo),
-			ASSERT(!"Unknown address family");
+			0
-			return false;
+		);
-		}
+		Lookup->Callback(ErrCode, Hostname);
-	}  // switch (address family)
+	});
-	return true;
 }
 
 
 
 
 
-void cIPLookup::Callback(int a_Result, char a_Type, int a_Count, int a_Ttl, void * a_Addresses, void * a_Self)
+void cIPLookup::Callback(int a_Result, const char * a_Address)
 {
-	// Get the Self class:
-	cIPLookup * Self = reinterpret_cast<cIPLookup *>(a_Self);
-	ASSERT(Self != nullptr);
-
 	// Call the proper callback based on the event received:
-	if ((a_Result != 0) || (a_Addresses == nullptr))
+	if ((a_Result != 0) || (a_Address == nullptr))
 	{
 		// An error has occurred, notify the error callback:
-		Self->m_Callbacks->OnError(a_Result, evutil_socket_error_to_string(a_Result));
+		m_Callbacks->OnError(a_Result, ErrorString(a_Result));
 	}
 	else
 	{
 		// Call the success handler:
-		Self->m_Callbacks->OnNameResolved(*(reinterpret_cast<char **>(a_Addresses)), Self->m_IP);
+		m_Callbacks->OnNameResolved(a_Address, m_IP);
-		Self->m_Callbacks->OnFinished();
+		m_Callbacks->OnFinished();
 	}
-	cNetworkSingleton::Get().RemoveIPLookup(Self);
 }
 
 
@@ -101,14 +93,7 @@ bool cNetwork::IPToHostName(
 	cNetwork::cResolveNameCallbacksPtr a_Callbacks
 )
 {
-	auto res = std::make_shared<cIPLookup>(a_Callbacks);
+	cIPLookup::Lookup(a_IP, std::move(a_Callbacks));
-	cNetworkSingleton::Get().AddIPLookup(res);
-	if (!res->Lookup(a_IP))
-	{
-		// Lookup failed early on, remove the object completely:
-		cNetworkSingleton::Get().RemoveIPLookup(res.get());
-		return false;
-	}
 	return true;
 }
 

src/OSSupport/IPLookup.h

@@ -21,12 +21,9 @@
 class cIPLookup
 {
 public:
-	/** Creates the lookup object. Doesn't start the lookup yet. */
-	cIPLookup(cNetwork::cResolveNameCallbacksPtr a_Callbacks);
 
-	/** Starts the lookup.
+	/** Creates a lookup object and schedules the lookup. */
-	Returns true if lookup started successfully, false on failure (invalid IP format etc.) */
+	static void Lookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
-	bool Lookup(const AString & a_IP);
 
 protected:
 
@@ -36,9 +33,11 @@ protected:
 	/** The IP that was queried (needed for the callbacks). */
 	AString m_IP;
 
+	/** Creates the lookup object. Doesn't start the lookup yet. */
+	cIPLookup(const AString & a_IP, cNetwork::cResolveNameCallbacksPtr a_Callbacks);
 
 	/** Callback that is called by LibEvent when there's an event for the request. */
-	static void Callback(int a_Result, char a_Type, int a_Count, int a_Ttl, void * a_Addresses, void * a_Self);
+	void Callback(int a_Result, const char * a_Address);
 };
 typedef SharedPtr<cIPLookup> cIPLookupPtr;
 typedef std::vector<cIPLookupPtr> cIPLookupPtrs;

src/OSSupport/NetworkLookup.cpp

@@ -0,0 +1,63 @@
+
+// NetworkLookup.cpp
+
+// Implements the cNetworkLookup class representing an executor for asynchronous lookup tasks
+
+
+#include "Globals.h"
+#include "NetworkLookup.h"
+
+
+
+
+cNetworkLookup::cNetworkLookup() :
+	cIsThread("NetworkLookup")
+{
+}
+
+
+
+
+
+cNetworkLookup::~cNetworkLookup()
+{
+	Stop();
+}
+
+
+
+
+
+void cNetworkLookup::ScheduleLookup(std::function<void()> a_Lookup)
+{
+	m_WorkQueue.EnqueueItem(std::move(a_Lookup));
+}
+
+
+
+
+
+void cNetworkLookup::Stop()
+{
+	m_ShouldTerminate = true;
+	m_WorkQueue.Clear();
+	m_WorkQueue.EnqueueItem([](){});  // Dummy work to wake up the thread
+	cIsThread::Stop();
+}
+
+
+
+
+
+void cNetworkLookup::Execute()
+{
+	while (!m_ShouldTerminate)
+	{
+		// Execute the next task in the queue
+		auto Work = m_WorkQueue.DequeueItem();
+		Work();
+	}
+}
+
+
+

src/OSSupport/NetworkLookup.h

@@ -0,0 +1,42 @@
+
+// NetworkLookup.h
+
+// Declares the cNetworkLookup class representing an executor for asynchronous lookup tasks
+
+#pragma once
+
+#include <functional>
+
+#include "IsThread.h"
+#include "Queue.h"
+
+
+
+
+
+class cNetworkLookup :
+	public cIsThread
+{
+public:
+
+	cNetworkLookup();
+	~cNetworkLookup();
+
+	/** Schedule a lookup task for execution. */
+	void ScheduleLookup(std::function<void()> a_Lookup);
+
+	/** Cancels any scheduled lookups and joins the lookup thread. */
+	void Stop();
+
+protected:
+
+	/** Process the queue until the thread is stopped. */
+	virtual void Execute() override final;
+
+private:
+
+	/** The queue of lookup tasks waiting to be executed. */
+	cQueue<std::function<void()>> m_WorkQueue;
+};
+
+

src/OSSupport/NetworkSingleton.cpp

@@ -8,15 +8,7 @@
 #include "NetworkSingleton.h"
 #include <event2/thread.h>
 #include <event2/bufferevent.h>
-#include <event2/dns.h>
 #include <event2/listener.h>
-#include "IPLookup.h"
-#include "HostnameLookup.h"
-
-#ifdef ANDROID
-	// For DNS server retrieval
-	#include <sys/system_properties.h>
-#endif
 
 
 
@@ -53,6 +45,9 @@ cNetworkSingleton & cNetworkSingleton::Get(void)
 
 void cNetworkSingleton::Initialise(void)
 {
+	// Start the lookup thread
+	m_LookupThread.Start();
+
 	// Windows: initialize networking:
 	#ifdef _WIN32
 		WSADATA wsaData;
@@ -86,24 +81,6 @@ void cNetworkSingleton::Initialise(void)
 		abort();
 	}
 
-	// Create the DNS lookup helper:
-	m_DNSBase = evdns_base_new(m_EventBase, 1);
-	if (m_DNSBase == nullptr)
-	{
-		LOGERROR("Failed to initialize LibEvent's DNS subsystem. The server will now terminate.");
-		abort();
-	}
-
-	#ifdef ANDROID
-		char PropertyBuffer[PROP_VALUE_MAX];
-
-		__system_property_get("net.dns1", PropertyBuffer);
-		evdns_base_nameserver_ip_add(m_DNSBase, PropertyBuffer);
-
-		__system_property_get("net.dns2", PropertyBuffer);
-		evdns_base_nameserver_ip_add(m_DNSBase, PropertyBuffer);
-	#endif
-
 	// Create the event loop thread:
 	m_HasTerminated = false;
 	m_EventLoopThread = std::thread(RunEventLoop, this);
@@ -118,6 +95,9 @@ void cNetworkSingleton::Terminate(void)
 {
 	ASSERT(!m_HasTerminated);
 
+	// Wait for the lookup thread to stop
+	m_LookupThread.Stop();
+
 	// Wait for the LibEvent event loop to terminate:
 	event_base_loopbreak(m_EventBase);
 	m_EventLoopThread.join();
@@ -127,12 +107,9 @@ void cNetworkSingleton::Terminate(void)
 		cCSLock Lock(m_CS);
 		m_Connections.clear();
 		m_Servers.clear();
-		m_HostnameLookups.clear();
-		m_IPLookups.clear();
 	}
 
 	// Free the underlying LibEvent objects:
-	evdns_base_free(m_DNSBase, true);
 	event_base_free(m_EventBase);
 
 	libevent_global_shutdown();
@@ -189,64 +166,6 @@ void cNetworkSingleton::SignalizeStartup(evutil_socket_t a_Socket, short a_Event
 
 
 
-void cNetworkSingleton::AddHostnameLookup(cHostnameLookupPtr a_HostnameLookup)
-{
-	ASSERT(!m_HasTerminated);
-	cCSLock Lock(m_CS);
-	m_HostnameLookups.push_back(a_HostnameLookup);
-}
-
-
-
-
-
-void cNetworkSingleton::RemoveHostnameLookup(const cHostnameLookup * a_HostnameLookup)
-{
-	ASSERT(!m_HasTerminated);
-	cCSLock Lock(m_CS);
-	for (auto itr = m_HostnameLookups.begin(), end = m_HostnameLookups.end(); itr != end; ++itr)
-	{
-		if (itr->get() == a_HostnameLookup)
-		{
-			m_HostnameLookups.erase(itr);
-			return;
-		}
-	}  // for itr - m_HostnameLookups[]
-}
-
-
-
-
-
-void cNetworkSingleton::AddIPLookup(cIPLookupPtr a_IPLookup)
-{
-	ASSERT(!m_HasTerminated);
-	cCSLock Lock(m_CS);
-	m_IPLookups.push_back(a_IPLookup);
-}
-
-
-
-
-
-void cNetworkSingleton::RemoveIPLookup(const cIPLookup * a_IPLookup)
-{
-	ASSERT(!m_HasTerminated);
-	cCSLock Lock(m_CS);
-	for (auto itr = m_IPLookups.begin(), end = m_IPLookups.end(); itr != end; ++itr)
-	{
-		if (itr->get() == a_IPLookup)
-		{
-			m_IPLookups.erase(itr);
-			return;
-		}
-	}  // for itr - m_IPLookups[]
-}
-
-
-
-
-
 void cNetworkSingleton::AddLink(cTCPLinkImplPtr a_Link)
 {
 	ASSERT(!m_HasTerminated);

src/OSSupport/NetworkSingleton.h

@@ -13,8 +13,10 @@
 
 #pragma once
 
+#include <atomic>
 #include <event2/event.h>
 #include "Network.h"
+#include "NetworkLookup.h"
 #include "CriticalSection.h"
 #include "Event.h"
 
@@ -24,19 +26,12 @@
 
 // fwd:
 struct event_base;
-struct evdns_base;
 class cTCPLinkImpl;
 typedef SharedPtr<cTCPLinkImpl> cTCPLinkImplPtr;
 typedef std::vector<cTCPLinkImplPtr> cTCPLinkImplPtrs;
 class cServerHandleImpl;
 typedef SharedPtr<cServerHandleImpl> cServerHandleImplPtr;
 typedef std::vector<cServerHandleImplPtr> cServerHandleImplPtrs;
-class cHostnameLookup;
-typedef SharedPtr<cHostnameLookup> cHostnameLookupPtr;
-typedef std::vector<cHostnameLookupPtr> cHostnameLookupPtrs;
-class cIPLookup;
-typedef SharedPtr<cIPLookup> cIPLookupPtr;
-typedef std::vector<cIPLookupPtr> cIPLookupPtrs;
 
 
 
@@ -63,24 +58,8 @@ public:
 	/** Returns the main LibEvent handle for event registering. */
 	event_base * GetEventBase(void) { return m_EventBase; }
 
-	/** Returns the LibEvent handle for DNS lookups. */
+	/** Returns the thread used to perform hostname and IP lookups */
-	evdns_base * GetDNSBase(void) { return m_DNSBase; }
+	cNetworkLookup & GetLookupThread() { return m_LookupThread; }
-
-	/** Adds the specified hostname lookup to m_HostnameLookups.
-	Used by the underlying lookup implementation when a new lookup is initiated. */
-	void AddHostnameLookup(cHostnameLookupPtr a_HostnameLookup);
-
-	/** Removes the specified hostname lookup from m_HostnameLookups.
-	Used by the underlying lookup implementation when the lookup is finished. */
-	void RemoveHostnameLookup(const cHostnameLookup * a_HostnameLookup);
-
-	/** Adds the specified IP lookup to M_IPLookups.
-	Used by the underlying lookup implementation when a new lookup is initiated. */
-	void AddIPLookup(cIPLookupPtr a_IPLookup);
-
-	/** Removes the specified IP lookup from m_IPLookups.
-	Used by the underlying lookup implementation when the lookup is finished. */
-	void RemoveIPLookup(const cIPLookup * a_IPLookup);
 
 	/** Adds the specified link to m_Connections.
 	Used by the underlying link implementation when a new link is created. */
@@ -104,26 +83,17 @@ protected:
 	/** The main LibEvent container for driving the event loop. */
 	event_base * m_EventBase;
 
-	/** The LibEvent handle for doing DNS lookups. */
-	evdns_base * m_DNSBase;
-
 	/** Container for all client connections, including ones with pending-connect. */
 	cTCPLinkImplPtrs m_Connections;
 
 	/** Container for all servers that are currently active. */
 	cServerHandleImplPtrs m_Servers;
 
-	/** Container for all pending hostname lookups. */
-	cHostnameLookupPtrs m_HostnameLookups;
-
-	/** Container for all pending IP lookups. */
-	cIPLookupPtrs m_IPLookups;
-
 	/** Mutex protecting all containers against multithreaded access. */
 	cCriticalSection m_CS;
 
 	/** Set to true if Terminate has been called. */
-	volatile bool m_HasTerminated;
+	std::atomic<bool> m_HasTerminated;
 
 	/** The thread in which the main LibEvent loop runs. */
 	std::thread m_EventLoopThread;
@@ -131,6 +101,9 @@ protected:
 	/** Event that is signalled once the startup is finished and the LibEvent loop is running. */
 	cEvent m_StartupEvent;
 
+	/** The thread on which hostname and ip address lookup is performed. */
+	cNetworkLookup m_LookupThread;
+
 
 	/** Converts LibEvent-generated log events into log messages in MCS log. */
 	static void LogCallback(int a_Severity, const char * a_Msg);

src/OSSupport/TCPLinkImpl.cpp

@@ -70,41 +70,75 @@ cTCPLinkImplPtr cTCPLinkImpl::Connect(const AString & a_Host, UInt16 a_Port, cTC
 	res->m_Callbacks->OnLinkCreated(res);
 	res->Enable(res);
 
-	// If a_Host is an IP address, schedule a connection immediately:
+	// Callback to connect after performing lookup:
-	sockaddr_storage sa;
+	class cHostnameCallback :
-	int salen = static_cast<int>(sizeof(sa));
+		public cNetwork::cResolveNameCallbacks
-	if (evutil_parse_sockaddr_port(a_Host.c_str(), reinterpret_cast<sockaddr *>(&sa), &salen) == 0)
 	{
-		// Insert the correct port:
+		cTCPLinkImplPtr m_Link;
-		if (sa.ss_family == AF_INET6)
+		UInt16 m_Port;
+		bool m_IsConnecting;
+
+	public:
+
+		cHostnameCallback(cTCPLinkImplPtr a_Link, UInt16 a_ConnectPort):
+			m_Link(std::move(a_Link)),
+			m_Port(a_ConnectPort),
+			m_IsConnecting(false)
 		{
-			reinterpret_cast<sockaddr_in6 *>(&sa)->sin6_port = htons(a_Port);
-		}
-		else
-		{
-			reinterpret_cast<sockaddr_in *>(&sa)->sin_port = htons(a_Port);
 		}
 
-		// Queue the connect request:
+		void DoConnect(const sockaddr * a_IP, int size)
-		if (bufferevent_socket_connect(res->m_BufferEvent, reinterpret_cast<sockaddr *>(&sa), salen) == 0)
 		{
-			// Success
+			// Make sure connect is only completed once
-			return res;
+			if (!m_IsConnecting)
+			{
+				int ErrCode = bufferevent_socket_connect(m_Link->m_BufferEvent, a_IP, size);
+				if (ErrCode == 0)
+				{
+					m_IsConnecting = true;
+				}
+				else
+				{
+					m_Link->GetCallbacks()->OnError(ErrCode, evutil_socket_error_to_string(ErrCode));
+				}
+			}
 		}
-		// Failure
-		cNetworkSingleton::Get().RemoveLink(res.get());
-		return nullptr;
-	}
 
-	// a_Host is a hostname, connect after a lookup:
+		virtual bool OnNameResolvedV4(const AString & a_Name, const sockaddr_in * a_IP) override
-	if (bufferevent_socket_connect_hostname(res->m_BufferEvent, cNetworkSingleton::Get().GetDNSBase(), AF_UNSPEC, a_Host.c_str(), a_Port) == 0)
+		{
-	{
+			sockaddr_in Addr = *a_IP;
-		// Success
+			Addr.sin_port = htons(m_Port);
-		return res;
+			DoConnect(reinterpret_cast<const sockaddr *>(&Addr), sizeof(Addr));
-	}
+			return false;  // Don't care about recieving ip as string
-	// Failure
+		}
-	cNetworkSingleton::Get().RemoveLink(res.get());
+
-	return nullptr;
+		virtual bool OnNameResolvedV6(const AString & a_Name, const sockaddr_in6 * a_IP) override
+		{
+			sockaddr_in6 Addr = *a_IP;
+			Addr.sin6_port = htons(m_Port);
+			DoConnect(reinterpret_cast<const sockaddr *>(&Addr), sizeof(Addr));
+			return false;  // Don't care about recieving ip as string
+		}
+
+		virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override
+		{
+			m_Link->GetCallbacks()->OnError(a_ErrorCode, a_ErrorMsg);
+			cNetworkSingleton::Get().RemoveLink(m_Link.get());
+		}
+
+		// Don't need to do anything for these
+		virtual void OnFinished() override
+		{
+		}
+
+		virtual void OnNameResolved(const AString & a_Name, const AString & a_IP) override
+		{
+		}
+	};
+
+	// Schedule the host query
+	cNetwork::HostnameToIP(a_Host, std::make_shared<cHostnameCallback>(res, a_Port));
+	return res;
 }
 
 

tests/Network/CMakeLists.txt

@@ -12,7 +12,9 @@ set (Network_SRCS
 	${CMAKE_SOURCE_DIR}/src/OSSupport/Event.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/HostnameLookup.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/IPLookup.cpp
+	${CMAKE_SOURCE_DIR}/src/OSSupport/IsThread.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/NetworkInterfaceEnum.cpp
+	${CMAKE_SOURCE_DIR}/src/OSSupport/NetworkLookup.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/NetworkSingleton.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/ServerHandleImpl.cpp
 	${CMAKE_SOURCE_DIR}/src/OSSupport/TCPLinkImpl.cpp
@@ -27,12 +29,16 @@ set (Network_SRCS
 set (Network_HDRS
 	${CMAKE_SOURCE_DIR}/src/OSSupport/CriticalSection.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/Event.h
+	${CMAKE_SOURCE_DIR}/src/OSSupport/GetAddressInfoError.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/HostnameLookup.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/IPLookup.h
+	${CMAKE_SOURCE_DIR}/src/OSSupport/IsThread.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/Network.h
+	${CMAKE_SOURCE_DIR}/src/OSSupport/NetworkLookup.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/NetworkSingleton.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/ServerHandleImpl.h
 	${CMAKE_SOURCE_DIR}/src/OSSupport/TCPLinkImpl.h
+	${CMAKE_SOURCE_DIR}/src/OSSupport/Queue.h
 	${CMAKE_SOURCE_DIR}/src/PolarSSL++/CtrDrbgContext.h
 	${CMAKE_SOURCE_DIR}/src/PolarSSL++/CryptoKey.h
 	${CMAKE_SOURCE_DIR}/src/PolarSSL++/EntropyContext.h