Consistent uplink processing

[skliper]

Is your feature request related to a problem? Please describe.
Since uplink processing relies on CFE_SB_ReceiveBuffer return (either receive or timeout), actual uplink processing can not be synchronized or scheduled reliably and is inconsistent. Also could flood the interface by simply providing a CI_Lab cmd in each set of 10 msgs.

ci_lab/fsw/src/ci_lab_app.c

Lines 91 to 110 in ed38aa2

	while (CFE_ES_RunLoop(&RunStatus) == true)
	{
	CFE_ES_PerfLogExit(CI_LAB_MAIN_TASK_PERF_ID);
	/* Pend on receipt of command packet -- timeout set to 500 millisecs */
	status = CFE_SB_ReceiveBuffer(&SBBufPtr, CI_LAB_Global.CommandPipe, 500);
	CFE_ES_PerfLogEntry(CI_LAB_MAIN_TASK_PERF_ID);
	if (status == CFE_SUCCESS)
	{
	CI_LAB_ProcessCommandPacket(SBBufPtr);
	}
	/* Regardless of packet vs timeout, always process uplink queue */
	if (CI_LAB_Global.SocketConnected)
	{
	CI_LAB_ReadUpLink();
	}
	}

Also hard coded to process up to 10 messages per return from CFE_SB_ReceiveBuffer.

Describe the solution you'd like
Separate uplink processing from command processing by using a timer/callback and child task. Could then actually limit uplink processing and provide more consistent behavior.

Describe alternatives you've considered
Could add an uplink processing command that could come from a scheduler and/or support both commands and timer callback.

Additional context
Would simplify faster than real time (FRT) execution to remove dependency of uplink processing on CFE_SB_ReceiveBuffer timeout.

Requester Info
Jacob Hageman - NASA/GSFC