publish NTCP2 ipv6 address if applicable

libi2pd/NTCP2.cpp

@@ -1179,6 +1179,8 @@ namespace transport
 		else
 		{
 			LogPrint (eLogDebug, "NTCP2: Connected to ", conn->GetSocket ().remote_endpoint ());
+			if (conn->GetSocket ().local_endpoint ().protocol () == boost::asio::ip::tcp::v6()) // ipv6
+				context.UpdateNTCP2V6Address (conn->GetSocket ().local_endpoint ().address ());
 			conn->ClientLogin ();
 		}
 	}

libi2pd/RouterContext.cpp

@@ -453,6 +453,41 @@ namespace i2p
 			UpdateRouterInfo ();
 	}
 
+	void RouterContext::UpdateNTCP2V6Address (const boost::asio::ip::address& host)
+	{
+		bool updated = false;
+		int port = 0;
+		auto& addresses = m_RouterInfo.GetAddresses ();
+		for (auto& addr: addresses)
+		{
+			if (addr->IsPublishedNTCP2 ())
+			{
+				if (addr->host.is_v6 ())
+				{
+					if (addr->host != host)
+					{
+						addr->host = host;
+						updated = true;
+						break;
+					}
+				}
+				else
+					port = addr->port; // NTCP2 v4
+			}
+		}
+
+		if (!updated) 
+		{
+			if (port) // we have found NTCP2 v4 but not v6
+			{
+				m_RouterInfo.AddNTCP2Address (m_NTCP2Keys->staticPublicKey, m_NTCP2Keys->iv);	
+				PublishNTCP2Address (port, true);
+			}
+		}
+		else
+			UpdateRouterInfo ();	
+	}
+
 	void RouterContext::UpdateStats ()
 	{
 		if (m_IsFloodfill)

libi2pd/RouterContext.h

@@ -100,6 +100,7 @@ namespace i2p
 			void SetSupportsV4 (bool supportsV4);
 
 			void UpdateNTCPV6Address (const boost::asio::ip::address& host); // called from NTCP session
+			void UpdateNTCP2V6Address (const boost::asio::ip::address& host); // called from NTCP2 session
 			void UpdateStats ();
 			void CleanupDestination ();	// garlic destination