path: root/src/OSSupport/NetworkSingleton.cpp

// NetworkSingleton.cpp

// Implements the cNetworkSingleton class representing the storage for global data pertaining to network API
// such as a list of all connections, all listening sockets and the LibEvent dispatch thread.

#include "Globals.h"
#include "NetworkSingleton.h"
#include <event2/event.h>
#include <event2/thread.h>
#include <event2/bufferevent.h>
#include <event2/dns.h>
#include <event2/listener.h>
#include "IPLookup.h"
#include "HostnameLookup.h"





cNetworkSingleton::cNetworkSingleton(void)
{
	// Windows: initialize networking:
	#ifdef _WIN32
		WSADATA wsaData;
		memset(&wsaData, 0, sizeof(wsaData));
		int res = WSAStartup (MAKEWORD(2, 2), &wsaData);
		if (res != 0)
		{
			int err = WSAGetLastError();
			LOGWARNING("WSAStartup failed: %d, WSAGLE = %d (%s)", res, err, evutil_socket_error_to_string(err));
			exit(1);
		}
	#endif  // _WIN32

	// Initialize LibEvent logging:
	event_set_log_callback(LogCallback);

	// Initialize threading:
	#if defined(EVTHREAD_USE_WINDOWS_THREADS_IMPLEMENTED)
		evthread_use_windows_threads();
	#elif defined(EVTHREAD_USE_PTHREADS_IMPLEMENTED)
		evthread_use_pthreads();
	#else
		#error No threading implemented for EVTHREAD
	#endif

	// Create the main event_base:
	m_EventBase = event_base_new();
	if (m_EventBase == nullptr)
	{
		LOGERROR("Failed to initialize LibEvent. The server will now terminate.");
		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();
	}

	// Create the event loop thread:
	std::thread EventLoopThread(RunEventLoop, this);
	EventLoopThread.detach();
}





cNetworkSingleton & cNetworkSingleton::Get(void)
{
	static cNetworkSingleton Instance;
	return Instance;
}





bool cNetworkSingleton::HostnameToIP(
	const AString & a_Hostname,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	try
	{
		// TODO: This has a race condition with possible memory leak:
		// If a lookup finishes immediately, the constructor calls the removal before this addition
		cCSLock Lock(m_CS);
		m_HostnameLookups.push_back(std::make_shared<cHostnameLookup>(a_Hostname, a_Callbacks));
	}
	catch (...)
	{
		return false;
	}
	return true;
}




bool cNetworkSingleton::IPToHostName(
	const AString & a_IP,
	cNetwork::cResolveNameCallbacksPtr a_Callbacks
)
{
	try
	{
		// TODO: This has a race condition with possible memory leak:
		// If a lookup finishes immediately, the constructor calls the removal before this addition
		cCSLock Lock(m_CS);
		m_IPLookups.push_back(std::make_shared<cIPLookup>(a_IP, a_Callbacks));
	}
	catch (...)
	{
		return false;
	}
	return true;
}




void cNetworkSingleton::LogCallback(int a_Severity, const char * a_Msg)
{
	switch (a_Severity)
	{
		case _EVENT_LOG_DEBUG: LOGD      ("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_MSG:   LOG       ("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_WARN:  LOGWARNING("LibEvent: %s", a_Msg); break;
		case _EVENT_LOG_ERR:   LOGERROR  ("LibEvent: %s", a_Msg); break;
		default:
		{
			LOGWARNING("LibEvent: Unknown log severity (%d): %s", a_Severity, a_Msg);
			break;
		}
	}
}





void cNetworkSingleton::RunEventLoop(cNetworkSingleton * a_Self)
{
	event_base_loop(a_Self->m_EventBase, EVLOOP_NO_EXIT_ON_EMPTY);
}





void cNetworkSingleton::RemoveHostnameLookup(const cHostnameLookup * a_HostnameLookup)
{
	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::RemoveIPLookup(const cIPLookup * a_IPLookup)
{
	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)
{
	cCSLock Lock(m_CS);
	m_Connections.push_back(a_Link);
}





void cNetworkSingleton::RemoveLink(const cTCPLinkImpl * a_Link)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_Connections.begin(), end = m_Connections.end(); itr != end; ++itr)
	{
		if (itr->get() == a_Link)
		{
			m_Connections.erase(itr);
			return;
		}
	}  // for itr - m_Connections[]
}





void cNetworkSingleton::AddServer(cServerHandleImplPtr a_Server)
{
	cCSLock Lock(m_CS);
	m_Servers.push_back(a_Server);
}





void cNetworkSingleton::RemoveServer(const cServerHandleImpl * a_Server)
{
	cCSLock Lock(m_CS);
	for (auto itr = m_Servers.begin(), end = m_Servers.end(); itr != end; ++itr)
	{
		if (itr->get() == a_Server)
		{
			m_Servers.erase(itr);
			return;
		}
	}  // for itr - m_Servers[]
}