KeepAlive doesn't work in FAR 3 distributions since 2021

[emuzychenko]

Since 2021, KeepAlive doesn't work in SSH connection in plugin versions supplied in FAR distribution. The log at level Debug 2 contains no KeepAlive records for both methods (null packets and dummy actions).

I found FAR 3.0.5588.1545 (2020) where both methods of KeepAlive works normally, the related records are logged.

[rohitab]

Please see FarGroup/FarManager#713 and my comment FarGroup/FarManager#713 (comment).

I believe this issue is due to the same reason, i.e. the FE_IDLE event and the DN_ENTERIDLE message were removed in FarGroup/FarManager@7af0fd7, and keep-alive messages depend on it. Due to the changes in the commit, the Idle() methods will not be called, and as you can in the code below, these methods are responsible for keeping the connection alive.

Far-NetBox/src/core/SftpFileSystem.cpp

Lines 2184 to 2205 in 518bfc3

	void TSFTPFileSystem::Idle()
	{
	// Keep session alive
	if ((GetSessionData()->GetPingType() != ptOff) &&
	((Now() - FSecureShell->GetLastDataSent()) > GetSessionData()->GetPingIntervalDT()))
	{
	if ((GetSessionData()->GetPingType() == ptDummyCommand) &&
	FSecureShell->GetReady())
	{
	FTerminal->LogEvent("Sending dummy command to keep session alive.");
	TSFTPPacket Packet(SSH_FXP_REALPATH, FCodePage);
	Packet.AddPathString(ROOTDIRECTORY, FUtfStrings);
	SendPacketAndReceiveResponse(&Packet, &Packet);
	}
	else
	{
	FSecureShell->KeepAlive();
	}
	}
	FSecureShell->Idle();
	}

Far-NetBox/src/core/ScpFileSystem.cpp

Lines 441 to 470 in 518bfc3

	void TSCPFileSystem::Idle()
	{
	// Keep session alive
	const TSessionData *Data = FTerminal->GetSessionData();
	if ((Data->GetPingType() != ptOff) &&
	(Now() - FSecureShell->GetLastDataSent() > Data->GetPingIntervalDT()))
	{
	if ((Data->GetPingType() == ptDummyCommand) &&
	FSecureShell->GetReady())
	{
	if (!FProcessingCommand)
	{
	ExecCommand(fsNull, 0);
	}
	else
	{
	FTerminal->LogEvent("Cannot send keepalive, command is being executed");
	// send at least SSH-level keepalive, if nothing else, it at least updates
	// LastDataSent, no the next keepalive attempt is postponed
	FSecureShell->KeepAlive();
	}
	}
	else
	{
	FSecureShell->KeepAlive();
	}
	}
	FSecureShell->Idle();
	}

Far-NetBox/src/core/FtpFileSystem.cpp

Lines 898 to 914 in 518bfc3

	void TFTPFileSystem::Idle()
	{
	if (FActive && !FWaitingForReply)
	{
	PoolForFatalNonCommandReply();
	// Keep session alive
	if ((FTerminal->GetSessionData()->GetFtpPingType() != ptOff) &&
	((Now() - FLastDataSent).GetValue() > FTerminal->GetSessionData()->GetFtpPingIntervalDT().GetValue() * 4))
	{
	FTerminal->LogEvent("Dummy directory read to keep session alive.");
	FLastDataSent = Now(); // probably redundant to the same statement in DoReadDirectory
	DummyReadDirectory(RemoteGetCurrentDirectory());
	}
	}
	}

[michaellukashov]

Fixed in latest builds https://nightly.link/michaellukashov/Far-NetBox/workflows/release/main?preview