DHCPClient.psm1
|
<#
.SYNOPSIS Gets an array of DHCP options for a DHCP-enabled network adapter. .DESCRIPTION The Get-DHCPOptions cmdlet retrieves the DHCP options from the registry for each DHCP-enabled network adapter. (Note that this registry information and format is subject to change.) .PARAMETER Vendor An optional flag indicating that vendor-specific DHCP options should return. .EXAMPLE Get-DHCPOptions .EXAMPLE Get-DHCPOptions -Vendor #> Function Get-DHCPOptions() { [cmdletbinding()] param ( [Parameter(Mandatory=$false)] [Switch]$Vendor = $false ) Process { #Iterate through NIC's with IP obtained via DHCP $objWin32NAC = Get-WmiObject -Class Win32_NetworkAdapterConfiguration -namespace "root\CIMV2" -computername "." -Filter "IPEnabled = 'True' AND DHCPEnabled ='True'" foreach ($objNACItem in $objWin32NAC) { #Read DHCP options $DhcpInterfaceOptions = (Get-ItemProperty -Path ("HKLM:\SYSTEM\CurrentControlSet\services\Tcpip\Parameters\Interfaces\{0}" -f $objNACItem.SettingID) -Name DhcpInterfaceOptions).DhcpInterfaceOptions $DhcpOptions = @(); for ( $i = 0 ; $i -lt 256; $i++ ) { $DhcpOptions += @("") } $DhcpVendorSpecificOptions = @(); for ( $i = 0 ; $i -lt 256; $i++ ) { $DhcpVendorSpecificOptions += @("") } #Iterate through DHCP options $intPosition = 0 while ($intPosition -lt $DhcpInterfaceOptions.length) { #Read Dhcp code $DhcpOptionCode = $DhcpInterfaceOptions[$intPosition] $intPosition = $intPosition + 8 #shift 8 bytes #Read length $DhcpOptionLength = $DhcpInterfaceOptions[$intPosition] $intPosition = $intPosition + 4 #shift 4 bytes #Is this a vendor specific option? $DhcpIsVendorSpecific = $DhcpInterfaceOptions[$intPosition] $intPosition = $intPosition + 4 #shift 4 bytes #Read "unknown data" $DhcpUnknownData = "" for ($i=0; $i -lt 4; $i++) { $DhcpUnknownData = $DhcpUnknownData + $DhcpInterfaceOptions[$intPosition + $i] } $intPosition = $intPosition + 4 #shift 4 bytes #Read value if (($DhcpOptionLength % 4) -eq 0) {$DhcpOptionBytesToRead = ($DhcpOptionLength - ($DhcpOptionLength % 4))} else {$DhcpOptionBytesToRead = ($DhcpOptionLength - ($DhcpOptionLength % 4)+4)} $DhcpOptionValue = New-Object Byte[] $DhcpOptionBytesToRead for ($i=0; $i -lt $DhcpOptionLength; $i++) { $DhcpOptionValue[$i] = $DhcpInterfaceOptions[$intPosition + $i] } $intPosition = $intPosition + $DhcpOptionBytesToRead #shift the number of bytes read #Add option to (vendor specific) array if ($DhcpIsVendorSpecific -eq 0) { $DhcpOptions[$DhcpOptionCode] = $DhcpOptionValue } else { $DhcpVendorSpecificOptions[$DhcpOptionCode] = $DhcpOptionValue } } } if ($Vendor) { return $DhcpVendorSpecificOptions } else { return $DhcpOptions } } } <# .SYNOPSIS Gets the value of a particular DHCP option, in string format. .DESCRIPTION The Get-DHCPOptionString cmdlet retrieves the value of a specific DHCP option, converted to a string. .PARAMETER Vendor An optional flag indicating that vendor-specific DHCP options should return. .PARAMETER OptionID The specific DHCP option to retrieve. .EXAMPLE Get-DHCPOptionString -OptionID 101 .EXAMPLE Get-DHCPOptions -Vendor -Optionid 234 #> Function Get-DHCPOptionString() { [cmdletbinding()] param ( [Parameter(Mandatory=$false)] [Switch]$Vendor = $false, [Parameter(Mandatory=$true)] $OptionID ) Process { $Encode = New-Object "System.Text.ASCIIEncoding" if ($vendor) { $options = Get-DHCPOptions -Vendor } else { $options = Get-DHCPOptions } return $Encode.GetString($options[$OptionID]) } } $tzMap = @{ "America/Anchorage" = "Alaskan Standard Time"; "America/Chicago" = "Central Standard Time"; "America/Denver" = "Mountain Standard Time"; "America/Los_Angeles" = "Pacific Standard Time"; "America/New_York" = "Eastern Standard Time"; "Asia/Jerusalem" = "Israel Standard Time"; "Asia/Shanghai" = "China Standard Time"; "Asia/Singapore" = "Singapore Standard Time"; "Asia/Tokyo" = "Tokyo Standard Time"; "Australia/Sydney" = "AUS Eastern Standard Time"; "Europe/Berlin" = "W. Europe Standard Time"; "Europe/Helsinki" = "FLE Standard Time"; "Europe/London" = "GMT Standard Time"; "Europe/Moscow" = "Russian Standard Time"; "Europe/Paris" = "Romance Standard Time"; "Europe/Warsaw" = "Central European Standard Time"; "Pacific/Honolulu" = "Hawaiian Standard Time" } <# .SYNOPSIS Gets the Windows time zone corresponding to the DHCP TZ option 101 value (TCODE), as described in https://tools.ietf.org/html/rfc4833. .DESCRIPTION The Get-DHCPTimeZone cmdlet translates the DHCP TCODE values, from the time zone database at https://www.iana.org/time-zones, into a Windows time zone id value, as used by the Set-TimeZone cmdlet. .EXAMPLE Get-DHCPTimeZone #> Function Get-DHCPTimeZone() { [cmdletbinding()] param ( ) Begin { Start-Process -FilePath "$PSScriptRoot\DHCPClient_TZ.exe" -Wait -WindowStyle hidden } Process { $dhcpTimeZone = Get-DHCPOptionString -OptionID 101 if ($tzMap[$dhcpTimeZone]) { return $tzMap[$dhcpTimeZone] } else { # Return a valid but unexpected value when we do not find a match return "Arab Standard Time" } } } |