goesrecv-packetmon.ps1

#####
# PowerShell implementation of nanomsg inspired by sam210723 https://github.com/sam210723/goesrecv-monitor/blob/master/goesrecv-monitor/Symbols.cs
# Logs all VCIDs and their packet counters to troubleshoot drops
# Edit the 3 lines below to match your goesrecv host, port, and location to save log file
#####

$ip = "192.168.1.137"
$port = "5004"
$logfile = "allpackets.csv"

#Initialize nanomsg subscription to goesrecv
[byte[]] $nninit = 0x00, 0x53, 0x50, 0x00, 0x00, 0x21, 0x00, 0x00

#Expected goesrecv response to nanomsg subscription
[byte[]] $nnires = 0x00, 0x53, 0x50, 0x00, 0x00, 0x20, 0x00, 0x00

#Set up other variables
$socket = New-Object System.Net.Sockets.Socket -ArgumentList $([System.Net.Sockets.SocketType]::Stream), $([System.Net.Sockets.ProtocolType]::Tcp)
$res = [System.Byte[]]::CreateInstance([System.Byte], 8)
$dres = [System.Byte[]]::CreateInstance([System.Byte], 65536)
$buffer = [System.Byte[]]::CreateInstance([System.Byte], 65536)

$num = 0
$totalBytes = 0

#Connect to goesrecv SDR sample publisher
try
{
	Write-Output "Connecting to goesresv host..."
	$socket.Connect($ip, $port)
	$socket.Send($nninit) | Out-Null
	$socket.Receive($res) | Out-Null

	if(-not [System.Linq.Enumerable]::SequenceEqual($nnires, $res))
	{
		Write-Warning "Could Not Connect to host"
		$socket.Close()
		exit
	}
}
catch
{
	Write-Warning "Could Not Connect to host"
	exit
}

Write-Output "Connected to goesresv host!"

#Create log file (if specified)
if(-not [String]::IsNullOrWhiteSpace($logfile)) {Set-Content -Path $logfile -Value "VCID,Packet Counter"}

#Listen for packets forever
$bytesBeforeHeader = 0
$packetCount = 0
do {

	try
	{
		#Recieve all available bytes
		$num = $socket.Receive($dres)
		$remainingBytesToWrite = $num
		$startReadingAt = 0

		#Loop through all the nanomsg headers
		while($remainingBytesToWrite -gt $bytesBeforeHeader)
		{
			#Write any information before the header
			if($bytesBeforeHeader -gt 0)
			{
				[System.Buffer]::BlockCopy($dres, $startReadingAt, $buffer, $totalBytes, $bytesBeforeHeader)
				$totalBytes += $bytesBeforeHeader
			}

			#Get next nanomsg packet length
			[System.Array]::Copy($dres, $bytesBeforeHeader + $startReadingAt, $res, 0, 8) | Out-Null
			if([Bitconverter]::IsLittleEndian) {[array]::Reverse($res)}
			$startReadingAt += $bytesBeforeHeader + 8
			$remainingBytesToWrite = $num - $startReadingAt
			$bytesBeforeHeader = [BitConverter]::ToUInt64($res, 0)
		}

		#No more headers in bytes we have; write the rest of the bytes
		[System.Buffer]::BlockCopy($dres, $startReadingAt, $buffer, $totalBytes, $remainingBytesToWrite)
		$bytesBeforeHeader -= $remainingBytesToWrite
		$totalBytes += $remainingBytesToWrite
	}
	catch
	{
		Write-Warning "Error parsing packet stream"
		$socket.Close()
		exit
	}

	#Parse for current channel
	$currentOffset = 0
	while($totalBytes -ge 892)
	{
		$vcid = $buffer[$currentOffset + 1] -band 0x3f
		$counter = ($buffer[$currentOffset + 2] -shl 16) -bor ($buffer[$currentOffset + 3] -shl 8) -bor $buffer[$currentOffset + 4]
		Add-Content -Path $logfile -Value "$vcid,$counter"
		$currentOffset += 892
		$totalBytes -= 892
	}

} while($num -ne 0)


#Clean Up after no packets were received from the server
Write-Warning "Connection to the server closed"
$socket.Close()