try to restart acceptors after termination of expired NTCP2 if no descriptors

libi2pd/NTCP2.cpp

@@ -1424,20 +1424,18 @@ namespace transport
 			else
 				LogPrint (eLogError, "NTCP2: Connected from error ", ec.message ());
 		}
-		else if (error == boost::asio::error::no_descriptors)
-		{
-			i2p::context.SetError (eRouterErrorNoDescriptors);
-			if (m_NoFileExhaustTimestamp < i2p::util::GetSecondsSinceEpoch () - NTCP2_DESCRIPTORS_EXHAUST_TIMEOUT)
-			{
-				m_NoFileExhaustTimestamp = i2p::util::GetSecondsSinceEpoch ();
-				LogPrint (eLogWarning, "NTCP2: WARNING! i2pd met file descriptors exhaustion! Please check your nofile limits!");
-			}
-		}
 		else
+		{	
 			LogPrint (eLogError, "NTCP2: Accept error ", error.message ());
-
+			if (error == boost::asio::error::no_descriptors)
+			{
+				i2p::context.SetError (eRouterErrorNoDescriptors);
+				return; 
+			}	
+		}	
+		
 		if (error != boost::asio::error::operation_aborted)
-		{
+		{			
 			if (!conn) // connection is used, create new one
 				conn = std::make_shared<NTCP2Session> (*this);
 			else // reuse failed
@@ -1464,26 +1462,21 @@ namespace transport
 				}
 			}
 			else
-				LogPrint (eLogError, "NTCP2: Connected from ipv6 error: ", ec.message ());
-		}
-		else if (error == boost::asio::error::no_descriptors)
-		{
-			i2p::context.SetErrorV6 (eRouterErrorNoDescriptors);
-			if (m_NoFileExhaustTimestamp < i2p::util::GetSecondsSinceEpoch () - NTCP2_DESCRIPTORS_EXHAUST_TIMEOUT)
-			{
-				m_NoFileExhaustTimestamp = i2p::util::GetSecondsSinceEpoch ();
-				LogPrint (eLogWarning, "NTCP2: WARNING! i2pd met file descriptors exhaustion! Please check your nofile limits!");
-			}
+				LogPrint (eLogError, "NTCP2: Connected from error ", ec.message ());
 		}
 		else
-			LogPrint (eLogError, "NTCP2: Accept ipv6 error: ", error.message ());
+		{	
+			LogPrint (eLogError, "NTCP2: Accept ipv6 error ", error.message ());
+			if (error == boost::asio::error::no_descriptors)
+			{
+				i2p::context.SetErrorV6 (eRouterErrorNoDescriptors);
+				return; 
+			}	
+		}	
 
 		if (error != boost::asio::error::operation_aborted)
 		{
-			if (!conn) // connection is used, create new one
-				conn = std::make_shared<NTCP2Session> (*this);
-			else // reuse failed
-				conn->Close ();
+			conn = std::make_shared<NTCP2Session> (*this);
 			m_NTCP2V6Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAcceptV6, this,
 				conn, std::placeholders::_1));
 		}
@@ -1524,8 +1517,24 @@ namespace transport
 				else
 					it++;
 			}
-
 			ScheduleTermination ();
+			
+			// try to restart acceptors if no description
+			// we do it after timer to let timer take descriptor first 
+			if (i2p::context.GetError () == eRouterErrorNoDescriptors)
+			{
+				i2p::context.SetError (eRouterErrorNone);
+				auto conn = std::make_shared<NTCP2Session> (*this);
+				m_NTCP2Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAccept, this,
+					conn, std::placeholders::_1));
+			}	
+			if (i2p::context.GetErrorV6 () == eRouterErrorNoDescriptors)
+			{
+				i2p::context.SetErrorV6 (eRouterErrorNone);
+				auto conn = std::make_shared<NTCP2Session> (*this);
+				m_NTCP2V6Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAcceptV6, this,
+					conn, std::placeholders::_1));
+			}	
 		}
 	}
 
@@ -1733,7 +1742,7 @@ namespace transport
 			});
 
 		boost::asio::async_read(conn->GetSocket(), boost::asio::buffer(readbuff->data (), SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE), // read min reply size
-			boost::asio::transfer_all(),
+		    boost::asio::transfer_all(),                    
 			[timer, conn, sz, readbuff](const boost::system::error_code & e, std::size_t transferred)
 			{
 				if (e)
@@ -1741,7 +1750,7 @@ namespace transport
 				else if (!(*readbuff)[1]) // succeeded
 				{
 					boost::system::error_code ec;
-					size_t moreBytes = conn->GetSocket ().available(ec);
+					size_t moreBytes = conn->GetSocket ().available(ec);	
 					if (moreBytes) // read remaining portion of reply if ipv6 received
 						boost::asio::read (conn->GetSocket (), boost::asio::buffer(readbuff->data (), moreBytes), boost::asio::transfer_all (), ec);
 					timer->cancel();

libi2pd/NTCP2.h

@@ -43,8 +43,6 @@ namespace transport
 	const int NTCP2_CLOCK_SKEW = 60; // in seconds
 	const int NTCP2_MAX_OUTGOING_QUEUE_SIZE = 500; // how many messages we can queue up
 
-	const int NTCP2_DESCRIPTORS_EXHAUST_TIMEOUT = 60; // 1 minute
-
 	enum NTCP2BlockType
 	{
 		eNTCP2BlkDateTime = 0,
@@ -288,8 +286,6 @@ namespace transport
 			std::unique_ptr<boost::asio::ip::tcp::endpoint> m_ProxyEndpoint;
 			std::shared_ptr<boost::asio::ip::tcp::endpoint> m_Address4, m_Address6, m_YggdrasilAddress;
 
-			uint64_t m_NoFileExhaustTimestamp;
-
 		public:
 
 			// for HTTP/I2PControl