############################################################################################################
#
# DHCP Migration Script 3.11.2. (c) Radio IP Software 2015
#
# Script to create a batch file that will contain netsh commands to
# update DHCP server with scope information contained in CSV file
# and to update client information contained in CSV file.
#
# Format of CSV scope file
# Scope Name, IP Address, NetMask, Network ID, Description
#
# Format of CSV client file
# Client Name, IP Address, NetMask, DNS1, DNS2, MAC Address, Lease Status
#
#
# Syntax:
# DHCPMigrationScript CSVScopeFileName CSVClientFileName  DhcpServerIpAddress CommandOutputFileName LeaseDurationToUse
#
# where
#
# CSVScopeFileName is CSV file name containing scopes information
# CSVClientFileName is CSV file name containing clients information
# DhcpServerIpAddress is the address of the DHCP server to update
# CommandOutputFileName is the file name used for output
# LeaseDurationToUse is an optional value for default lease duration
#
############################################################################################################

param([string] $CSVScopeFileName, [string] $CSVClientFileName, [string] $DhcpServerIpAddress, [string] $CommandOutputFileName, [string] $LeaseDurationToUse)

Set-Variable defaultLeaseDuration -option Constant -value 691200
Set-Variable setRouterOptionID -option Constant -value 3
Set-Variable setLeaseDurationOptionID -option Constant -value 51

[string] $scopeCSVFileName = $CSVScopeFileName
[string] $clientCSVFileName = $CSVClientFileName
[string] $dhcpServer = $DhcpServerIpAddress
[string] $cmdFileName = $CommandOutputFileName
[string] $leaseDuration = $LeaseDurationToUse

[object] $importScopesList = $null
[object] $importClientsList = $null

Function DisplayScriptSyntax
{
	write-host @"
	
Syntax:
DHCPMigrationScript CSVScopeFileName CSVClientFileName  DhcpServerIpAddress CommandOutputFileName [LeaseDurationToUse]

where

CSVScopeFileName is CSV file name containing scopes information
CSVClientFileName is CSV file name containing clients information
DhcpServerIpAddress is the IP address of the DHCP server to update
CommandOutputFileName is the file name used for output
LeaseDurationToUse is an optional value for default lease duration

"@
}

Function DisplayScriptContent
{
	Write-Host -ForegroundColor Red @"
DHCP Migration Script 3.11.2 loaded. (c) Radio IP Software 2015
"@
	write-host -ForegroundColor White @"
Available function:
  dhcp-CreateScript           Creates a batch file that will contain netsh commands to
                              update DHCP server with scope information contained in CSV file
                              and client information contained in CSV file.

"@
}

Function AddDHCPScope($ScopeName, $NetworkID, $NetMask, $Description)
{
	write-host Adding scope [$ScopeName] Network ID [$NetworkID] mask [$NetMask] Description [$Description] on DHCP Server [$dhcpServer]

	write-host COMMAND : netsh dhcp server $dhcpServer add scope $NetworkID $NetMask $ScopeName $Description
	add-content	$cmdFileName "netsh dhcp server $dhcpServer add scope $NetworkID $NetMask $ScopeName $Description"
}

Function AddDHCPRangeForScope($NetworkID, $NetMask)
{
	write-host Adding range for scope [$NetworkID] mask [$NetMask] on DHCP Server [$dhcpServer]

	[uint32] $ip = IpAddressToInt $NetworkID
	[uint32] $mask = IpAddressToInt $NetMask

	[uint32] $startAddress = ($ip + 1) -band [Uint32]::MaxValue
	[uint32] $endAddress = (($ip -bor $(-bnot $mask)) - 1) -band [Uint32]::MaxValue

	[string] $startAddressString = IpAddressToString($startAddress)
	[string] $endAddressString = IpAddressToString($endAddress)

	write-host COMMAND : netsh dhcp server $dhcpServer scope $NetworkID add iprange $startAddressString $endAddressString
	add-content	$cmdFileName "netsh dhcp server $dhcpServer scope $NetworkID add iprange $startAddressString $endAddressString"
}

Function ExcludeIpFromRange($NetworkID, $IpAddress)
{
	write-host Excluding IP [$IpAddress] for scope [$NetworkID] on DHCP Server [$dhcpServer]

	write-host COMMAND : netsh dhcp server $dhcpServer scope $NetworkID add excluderange $IpAddress $IpAddress
	add-content	$cmdFileName "netsh dhcp server $dhcpServer scope $NetworkID add excluderange $IpAddress $IpAddress"
}

Function SetRouterOption($NetworkID, $IpAddress)
{
	write-host Setting router option for IP [$IpAddress] for scope [$NetworkID] on DHCP Server [$dhcpServer]

	write-host COMMAND : netsh dhcp server $dhcpServer scope $NetworkID set optionvalue $setRouterOptionID IPADDRESS $IpAddress
	add-content	$cmdFileName "netsh dhcp server $dhcpServer scope $NetworkID set optionvalue $setRouterOptionID IPADDRESS $IpAddress"
}

Function SetLeaseDuration($NetworkID, $leaseDuration)
{
	write-host Setting lease duration to [$leaseDuration] for scope [$NetworkID] on DHCP Server [$dhcpServer]

	write-host COMMAND : netsh dhcp server $dhcpServer scope $NetworkID set optionvalue $setLeaseDurationOptionID DWORD $leaseDuration
	add-content	$cmdFileName "netsh dhcp server $dhcpServer scope $NetworkID set optionvalue $setLeaseDurationOptionID DWORD $leaseDuration"
}

Function AddCmdFileAddScope()
{
	write-host
	write-host Adding scopes -foregroundcolor blue -backgroundcolor black
	write-host

	add-content	$cmdFileName "rem"
	add-content	$cmdFileName "rem Adding scopes"
	add-content	$cmdFileName "rem"
}

Function AddScope()
{
	AddCmdFileAddScope
	
	# Step through Each Item in the Scope List
	foreach ($scope in $importScopesList)
	{
		if ( $scope.'Scope Name' )
		{
			AddDHCPScope $scope.'Scope Name' $scope.'Network ID' $scope.'NetMask' $scope.'Description'
			AddDHCPRangeForScope $scope.'Network ID' $scope.'NetMask'
			ExcludeIpFromRange $scope.'Network ID' $scope.'IP Address'
			SetRouterOption $scope.'Network ID' $scope.'IP Address'
			
			if ( !$leaseDuration )
			{
				SetLeaseDuration $scope.'Network ID' $defaultLeaseDuration
			}
			else
			{
				SetLeaseDuration $scope.'Network ID' $leaseDuration
			}
		}
	}
}

# IP Address network order change
Function HTONL([uint32] $ipAddress)
{
	return [int32] ([Convert]::ToInt64([IPAddress]::NetworkToHostOrder($ipAddress)) / ([Uint32]::MaxValue + 1)) -band [Uint32]::MaxValue
}
 
# IP Address converted and returned in host order
Function IpAddressToInt([string] $IpAddress)
{
	[IPAddress] $ip = $IpAddress
	
	[uint32] $ipToByte= [BitConverter]::ToInt32($ip.GetAddressBytes(), 0) -band [Uint32]::MaxValue
	return HTONL $ipToByte
}

# IP Address converted and returned in string
Function IpAddressToString([uint32] $IpAddress)
{
	[IPAddress] $ip = HTONL $IpAddress
	return [string] $ip.ToString()
}

# Remove all - from mac address
Function RemoveDashFromMac([string] $MacAddress)
{
	return [string] $MacAddress -replace "-", ""
}

Function ReservedClientAddressInDHCPScope($ClientName, $IpAddress, $NetMask, $MacAddress)
{
	[uint32] $ip = IpAddressToInt $IpAddress
	[uint32] $mask = IpAddressToInt $NetMask

	[uint32] $NetworkID = $ip -band $mask

	[string] $NetworkIDString = IpAddressToString($NetworkID)
	write-host Adding client [$ClientName] with IP [$IPAddress], Netmask [$NetMask], MAC [$MacAddress] to reservations for scope [$NetworkIDString] on DHCP Server [$dhcpServer]

	[string] $strippedMac = RemoveDashFromMac $MacAddress
	
	write-host netsh dhcp server $dhcpServer scope $NetworkIDString add reservedip $IpAddress $strippedMac $ClientName
	add-content	$cmdFileName "netsh dhcp server $dhcpServer scope $NetworkIDString add reservedip $IpAddress $strippedMac $ClientName"
}

Function AddCmdFileClientsToScopeText
{
	write-host
	write-host Adding clients -foregroundcolor blue -backgroundcolor black
	write-host

	add-content	$cmdFileName "rem"
	add-content	$cmdFileName "rem Adding clients to scopes"
	add-content	$cmdFileName "rem"
}

Function AddClientToScope()
{
	AddCmdFileClientsToScopeText

	# Step through Each Item in the List
	foreach ($client in $importClientsList)
	{
		if ( $client.'Client Name' )
		{
			if ( $client.'Lease Status' -eq "Reserved" )
			{
				ReservedClientAddressInDHCPScope $client.'Client Name' $client.'IP Address' $client.'NetMask' $client.'MAC Address' $client.'Lease Status'
			}
		}
	}
}

Function AddCmdFileHeaderText()
{
	write-host
	write-host Starting script with parameters [$scopeCSVFileName] [$clientCSVFileName], [$dhcpServer] [$cmdFileName] [$leaseDuration] -foregroundcolor yellow -backgroundcolor black
	write-host

	add-content	$cmdFileName "rem ######################################################################"
	add-content	$cmdFileName "rem Creating command file name for DHCP Server [$dhcpServer]"
	add-content	$cmdFileName "rem ######################################################################"
	add-content	$cmdFileName "rem"
}

Function AddCmdFileFooterText()
{
	add-content	$cmdFileName "rem"
	add-content	$cmdFileName "rem ######################################################################"
	add-content	$cmdFileName "rem Commands are ready to update DHCP Server [$dhcpServer]"
	add-content	$cmdFileName "rem Make sure you have sufficient privileges to modify DHCP server"
	add-content	$cmdFileName "rem ######################################################################"

	write-host
	write-host End of script -foregroundcolor yellow -backgroundcolor black
	write-host
}

Function CheckParameters()
{
	if ( !$scopeCSVFileName -or !$clientCSVFileName -or !$dhcpServer -or !$cmdFileName )
	{
		return $false
	}
	
	return $true
}

Function RunScript
{
	# Import list of scopes or clients from CSV
	$importScopesList=IMPORT-CSV $scopeCSVFileName
	$importClientsList=IMPORT-CSV $clientCSVFileName
	 
	# Make sure file is empty
	if ( $cmdFileName -and $(Test-path $cmdFileName) )
	{
		clear-content $cmdFileName
	}

	AddCmdFileHeaderText

	AddScope

	AddClientToScope 

	AddCmdFileFooterText

	Start-Process $cmdFileName
}

Function global:dhcp-CreateScript([Parameter(Mandatory=$true)] [string] $CSVScopeFileName, [Parameter(Mandatory=$true)] [string] $CSVClientFileName, [Parameter(Mandatory=$true)] [string] $DhcpServerIpAddress, [Parameter(Mandatory=$true)] [string] $CommandOutputFileName, $LeaseDurationToUse)
{
	$scopeCSVFileName = $CSVScopeFileName
	$clientCSVFileName = $CSVClientFileName
	$dhcpServer = $DhcpServerIpAddress
	$cmdFileName = $CommandOutputFileName
	$leaseDuration = $LeaseDurationToUse

	RunScript
}

switch ($psboundparameters.count)
{
	0 {DisplayScriptContent}
	4 {RunScript}
	5 {RunScript}
	default {DisplayScriptSyntax}
}