PSDiscoveryProtocol.psm1
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#region function Capture-CDPPacket function Capture-CDPPacket { <# .SYNOPSIS Capture CDP packets on local or remote computers .DESCRIPTION Capture CDP packets on local or remote computers. Cisco devices will by default send CDP announcements every 60 seconds. This cmdlet will start a packet capture and save the captured packets in a temporary ETL file. Only the first CDP packet in the ETL file will be returned. Requires elevation (Run as Administrator). WinRM and PowerShell remoting must be enabled on the target computer. .PARAMETER ComputerName Specifies one or more computers on which to capture CDP packets. Defaults to $env:COMPUTERNAME. .PARAMETER Duration Specifies the duration for which the CDP packets are captured, in seconds. Defaults to 62. .EXAMPLE PS> $Packet = Capture-CDPPacket PS> Parse-CDPPacket -Packet $Packet Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 .EXAMPLE PS> Capture-CDPPacket -Computer COMPUTER1 | Parse-CDPPacket Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 .EXAMPLE PS> 'COMPUTER1', 'COMPUTER2' | Capture-CDPPacket | Parse-CDPPacket Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 Port : FastEthernet0/2 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 20 #> [CmdletBinding()] param( [Parameter(Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)] [Alias('CN', 'Computer')] [String[]]$ComputerName = $env:COMPUTERNAME, [Parameter(Position=1)] [Int16]$Duration = 62 ) begin { $Identity = [Security.Principal.WindowsIdentity]::GetCurrent() $Principal = New-Object Security.Principal.WindowsPrincipal $Identity if (-not $Principal.IsInRole([Security.Principal.WindowsBuiltinRole]::Administrator)) { throw 'Capture-CDPPacket requires elevation. Please run PowerShell as administrator.' } } process { foreach ($Computer in $ComputerName) { try { $CimSession = New-CimSession -ComputerName $Computer -ErrorAction Stop } catch { Write-Warning "Unable to create CimSession. Please make sure WinRM and PSRemoting is enabled on $Computer." continue } $ETLFile = Invoke-Command -ComputerName $Computer -ScriptBlock { $TempFile = New-TemporaryFile Rename-Item -Path $TempFile.FullName -NewName $TempFile.FullName.Replace('.tmp', '.etl') -PassThru } $Adapter = Get-NetAdapter -Physical -CimSession $CimSession | Where-Object {$_.Status -eq 'Up' -and $_.InterfaceType -eq 6} | Select-Object -First 1 -ExpandProperty Name if ($Adapter) { $Session = New-NetEventSession -Name CDP -LocalFilePath $ETLFile.FullName -CaptureMode SaveToFile -CimSession $CimSession Add-NetEventPacketCaptureProvider -SessionName CDP -LinkLayerAddress '01-00-0c-cc-cc-cc' -TruncationLength 1024 -CaptureType BothPhysicalAndSwitch -CimSession $CimSession | Out-Null Add-NetEventNetworkAdapter -Name $Adapter -PromiscuousMode $True -CimSession $CimSession | Out-Null Start-NetEventSession -Name CDP -CimSession $CimSession $Seconds = $Duration $End = (Get-Date).AddSeconds($Seconds) while ($End -gt (Get-Date)) { $SecondsLeft = $End.Subtract((Get-Date)).TotalSeconds $Percent = ($Seconds - $SecondsLeft) / $Seconds * 100 Write-Progress -Activity "CDP Packet Capture" -Status "Capturing on $Computer..." -SecondsRemaining $SecondsLeft -PercentComplete $Percent [System.Threading.Thread]::Sleep(500) } Stop-NetEventSession -Name CDP -CimSession $CimSession $Log = Invoke-Command -ComputerName $Computer -ScriptBlock { Get-WinEvent -Path $args[0] -Oldest | Where-Object { $_.Id -eq 1001 -and [UInt16]0x2000 -eq [BitConverter]::ToUInt16($_.Properties[3].Value[21..20], 0) } | Select-Object -Last 1 -ExpandProperty Properties } -ArgumentList $Session.LocalFilePath Remove-NetEventSession -Name CDP -CimSession $CimSession Start-Sleep -Seconds 2 Invoke-Command -ComputerName $Computer -ScriptBlock { Remove-Item -Path $args[0] -Force } -ArgumentList $ETLFile.FullName if ($Log) { $Packet = $Log[3].Value ,$Packet } else { Write-Warning "No CDP packets captured on $Computer in $Seconds seconds." return } } else { Write-Warning "Unable to find a connected wired adapter on $Computer." return } } } end {} } #endregion #region function Parse-CDPPacket function Parse-CDPPacket { <# .SYNOPSIS Parse CDP packet returned from Capture-CDPPacket. .DESCRIPTION Parse CDP packet to get port, device, model, ipaddress and vlan. .PARAMETER Packet Array of one or more byte arrays from Capture-CDPPacket. .EXAMPLE PS> $Packet = Capture-CDPPacket PS> Parse-CDPPacket -Packet $Packet Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 .EXAMPLE PS> Capture-CDPPacket -Computer COMPUTER1 | Parse-CDPPacket Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 .EXAMPLE PS> 'COMPUTER1', 'COMPUTER2' | Capture-CDPPacket | Parse-CDPPacket Port : FastEthernet0/1 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 10 Port : FastEthernet0/2 Device : SWITCH1.domain.example Model : cisco WS-C2960-48TT-L IPAddress : 192.0.2.10 VLAN : 20 #> [CmdletBinding()] param( [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)] [object[]]$Packet ) begin {} process { $Offset = 26 $Hash = @{} while ($Offset -lt ($Packet.Length - 4)) { $Type = [BitConverter]::ToUInt16($Packet[($Offset + 1)..$Offset], 0) $Length = [BitConverter]::ToUInt16($Packet[($Offset + 3)..($Offset + 2)], 0) switch ($Type) { 1 { $Hash.Add('Device', [System.Text.Encoding]::ASCII.GetString($Packet[($Offset + 4)..($Offset + $Length)])) } 2 { $Hash.Add('IPAddress', ([System.Net.IPAddress][byte[]]$Packet[($Offset + 13)..($Offset + 16)]).IPAddressToString) } 3 { $Hash.Add('Port', [System.Text.Encoding]::ASCII.GetString($Packet[($Offset + 4)..($Offset + $Length)])) } 6 { $Hash.Add('Model', [System.Text.Encoding]::ASCII.GetString($Packet[($Offset + 4)..($Offset + $Length)])) } 10 { $Hash.Add('VLAN', [BitConverter]::ToUInt16($Packet[($Offset + 5)..($Offset + 4)], 0)) } } if ($Length -eq 0 ) { $Offset = $Packet.Length } $Offset = $Offset + $Length } return [PSCustomObject]$Hash } end {} } #endregion #region function Capture-LLDPPacket function Capture-LLDPPacket { <# .SYNOPSIS Capture LLDP packets on local or remote computers .DESCRIPTION Capture LLDP packets on local or remote computers. This cmdlet will start a packet capture and save the captured packets in a temporary ETL file. Only the first LLDP packet in the ETL file will be returned. Requires elevation (Run as Administrator). WinRM and PowerShell remoting must be enabled on the target computer. .PARAMETER ComputerName Specifies one or more computers on which to capture LLDP packets. Defaults to $env:COMPUTERNAME. .PARAMETER Duration Specifies the duration for which the LLDP packets are captured, in seconds. Defaults to 32. .EXAMPLE PS> $Packet = Capture-LLDPPacket PS> Parse-LLDPPacket -Packet $Packet Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 .EXAMPLE PS> Capture-LLDPPacket -Computer COMPUTER1 | Parse-LLDPPacket Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 .EXAMPLE PS> 'COMPUTER1', 'COMPUTER2' | Capture-LLDPPacket | Parse-LLDPPacket Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 Model : WS-C2960-48TT-L Description : IT Workstation VLAN : 20 Port : Fa0/2 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 #> [CmdletBinding()] param( [Parameter(Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)] [Alias('CN', 'Computer')] [String[]]$ComputerName = $env:COMPUTERNAME, [Parameter(Position=1)] [Int16]$Duration = 32 ) begin { $Identity = [Security.Principal.WindowsIdentity]::GetCurrent() $Principal = New-Object Security.Principal.WindowsPrincipal $Identity if (-not $Principal.IsInRole([Security.Principal.WindowsBuiltinRole]::Administrator)) { throw 'Capture-LLDPPacket requires elevation. Please run PowerShell as administrator.' } } process { foreach ($Computer in $ComputerName) { try { $CimSession = New-CimSession -ComputerName $Computer -ErrorAction Stop } catch { Write-Warning "Unable to create CimSession. Please make sure WinRM and PSRemoting is enabled on $Computer." continue } $ETLFile = Invoke-Command -ComputerName $Computer -ScriptBlock { $TempFile = New-TemporaryFile Rename-Item -Path $TempFile.FullName -NewName $TempFile.FullName.Replace('.tmp', '.etl') -PassThru } $Adapter = Get-NetAdapter -Physical -CimSession $CimSession | Where-Object {$_.Status -eq 'Up' -and $_.InterfaceType -eq 6} | Select-Object -First 1 Name, MacAddress $MACAddress = [PhysicalAddress]::Parse($Adapter.MacAddress).ToString() if ($Adapter) { $Session = New-NetEventSession -Name LLDP -LocalFilePath $ETLFile.FullName -CaptureMode SaveToFile -CimSession $CimSession Add-NetEventPacketCaptureProvider -SessionName LLDP -EtherType 0x88CC -TruncationLength 1024 -CaptureType BothPhysicalAndSwitch -CimSession $CimSession | Out-Null Add-NetEventNetworkAdapter -Name $Adapter.Name -PromiscuousMode $True -CimSession $CimSession | Out-Null Start-NetEventSession -Name LLDP -CimSession $CimSession $Seconds = $Duration $End = (Get-Date).AddSeconds($Seconds) while ($End -gt (Get-Date)) { $SecondsLeft = $End.Subtract((Get-Date)).TotalSeconds $Percent = ($Seconds - $SecondsLeft) / $Seconds * 100 Write-Progress -Activity "LLDP Packet Capture" -Status "Capturing on $Computer..." -SecondsRemaining $SecondsLeft -PercentComplete $Percent [System.Threading.Thread]::Sleep(500) } Stop-NetEventSession -Name LLDP -CimSession $CimSession $Log = Invoke-Command -ComputerName $Computer -ScriptBlock { Get-WinEvent -Path $args[0] -Oldest | Where-Object { $_.Id -eq 1001 -and [UInt16]0x88CC -eq [BitConverter]::ToUInt16($_.Properties[3].Value[13..12], 0) -and $MACAddress -ne [PhysicalAddress]::new($_.Properties[3].Value[6..11]).ToString() } | Select-Object -Last 1 -ExpandProperty Properties } -ArgumentList $Session.LocalFilePath Remove-NetEventSession -Name LLDP -CimSession $CimSession Start-Sleep -Seconds 2 Invoke-Command -ComputerName $Computer -ScriptBlock { Remove-Item -Path $args[0] -Force } -ArgumentList $ETLFile.FullName if ($Log) { $Packet = $Log[3].Value ,$Packet } else { Write-Warning "No LLDP packets captured on $Computer in $Seconds seconds." return } } else { Write-Warning "Unable to find a connected wired adapter on $Computer." return } } } end {} } #endregion #region function Parse-LLDPPacket function Parse-LLDPPacket { <# .SYNOPSIS Parse LLDP packet returned from Capture-LLDPPacket. .DESCRIPTION Parse LLDP packet to get port, description, device, model, ipaddress and vlan. .PARAMETER Packet Array of one or more byte arrays from Capture-LLDPPacket. .EXAMPLE PS> $Packet = Capture-LLDPPacket PS> Parse-LLDPPacket -Packet $Packet Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 .EXAMPLE PS> Capture-LLDPPacket -Computer COMPUTER1 | Parse-LLDPPacket Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 .EXAMPLE PS> 'COMPUTER1', 'COMPUTER2' | Capture-LLDPPacket | Parse-LLDPPacket Model : WS-C2960-48TT-L Description : HR Workstation VLAN : 10 Port : Fa0/1 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 Model : WS-C2960-48TT-L Description : IT Workstation VLAN : 20 Port : Fa0/2 Device : SWITCH1.domain.example IPAddress : 192.0.2.10 #> [CmdletBinding()] param( [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true)] [object[]]$Packet ) begin {} process { $Destination = [PhysicalAddress]::new($Packet[0..5]) $Source = [PhysicalAddress]::new($Packet[6..11]) $LLDP = [BitConverter]::ToUInt16($Packet[13..12], 0) $Offset = 14 $Mask = 0x01FF $Hash = @{} while ($Offset -lt $Packet.Length) { $Type = $Packet[$Offset] -shr 1 $Length = [BitConverter]::ToUInt16($Packet[($Offset + 1)..$Offset], 0) -band $Mask $Offset += 2 switch ($Type) { 1 { # Chassis ID $Subtype = $Packet[$Offset] $Offset += 1 $Length -= 1 if ($Subtype -eq 4) { $ChassisID = [PSCustomObject] @{ Type = 'MAC Address' ID = [PhysicalAddress]::new($Packet[$Offset..($Offset + 5)]) } $Offset += 6 } if ($Subtype -eq 6) { $ChassisID = [PSCustomObject] @{ Type = 'Interface Name' ID = [System.Text.Encoding]::ASCII.GetString($Packet[$Offset..($Offset + $Length)]) } $Offset += $Length } break } 2 { $Hash.Add('Port', [System.Text.Encoding]::ASCII.GetString($Packet[($Offset + 1)..($Offset + $Length - 1)])) $Offset += $Length break } 4 { $Hash.Add('Description', [System.Text.Encoding]::ASCII.GetString($Packet[$Offset..($Offset + $Length - 1)])) $Offset += $Length break } 5 { $Hash.Add('Device', [System.Text.Encoding]::ASCII.GetString($Packet[$Offset..($Offset + $Length - 1)])) $Offset += $Length break } 8 { $AddrLen = $Packet[($Offset)] $Subtype = $Packet[($Offset + 1)] if ($Subtype -eq 1) { $Hash.Add('IPAddress', ([System.Net.IPAddress][byte[]]$Packet[($Offset + 2)..($Offset + $AddrLen)]).IPAddressToString) } $Offset += $Length break } 127 { $OUI = [System.BitConverter]::ToString($Packet[($Offset)..($Offset + 2)]) if ($OUI -eq '00-12-BB') { $Subtype = $Packet[($Offset + 3)] if ($Subtype -eq 10) { $Hash.Add('Model', [System.Text.Encoding]::ASCII.GetString($Packet[($Offset + 4)..($Offset + $Length - 1)])) $Offset += $Length break } } if ($OUI -eq '00-80-C2') { $Subtype = $Packet[($Offset + 3)] if ($Subtype -eq 1) { $Hash.Add('VLAN', [BitConverter]::ToUInt16($Packet[($Offset + 5)..($Offset + 4)], 0)) $Offset += $Length break } } $Tlv = [PSCustomObject] @{ Type = $Type Value = [System.Text.Encoding]::ASCII.GetString($Packet[$Offset..($Offset + $Length)]) } Write-Verbose $Tlv $Offset += $Length break } default { $Tlv = [PSCustomObject] @{ Type = $Type Value = [System.Text.Encoding]::ASCII.GetString($Packet[$Offset..($Offset + $Length)]) } Write-Verbose $Tlv $Offset += $Length break } } } [PSCustomObject]$Hash } end {} } #endregion |