helpers/icmp.psm1
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Function Invoke-ICMPPMTUD { #If you change order of params, you must change the order of invoke-command params to match [CmdletBinding(DefaultParameterSetName = 'PMTUD')] param ( [Parameter(Mandatory=$true, Position=0)] [Alias("Sender","SourceIP")] [string] $Source, [Parameter(Mandatory=$true, Position=1)] [Alias("Receiver", "DestinationIP", "RemoteIP", "Target")] [string] $Destination, [Parameter(Mandatory=$false, Position=2)] [int] $StartBytes = 32, [Parameter(Mandatory=$false, Position=3)] [int] $EndBytes = 10000, [Parameter(Mandatory=$false, Position=4)] [Switch] $Reliability = $false, [Parameter(Mandatory=$false, Position=5)] [int] $Count = 1000, [Parameter(Mandatory=$false, Position=6)] [int] $testTime = 15, # Used for Write-Progress must also specify ParentID [Parameter(Mandatory=$false, Position=7)] [int] $ID, # Used for Write-Progress must also specify ID [Parameter(Mandatory=$false, Position=8)] [int] $ParentID ) #region Start-Ping: This function needs to be nested for sending remotely via Invoke-Command (e.g. Function:\Invoke-ICMPPMTU) Function Start-Ping { param ( [Parameter(Mandatory=$true, Position=0)] [Alias("Sender","SourceIP")] [string] $Source, [Parameter(Mandatory=$true, Position=1)] [Alias("Receiver", "DestinationIP", "RemoteIP", "Target")] [string] $Destination, [Parameter(Mandatory=$false, Position=2)] [int] $Size = 32, [Parameter(Mandatory=$false, Position=3)] [Switch] $RTT ) Add-Type @" using System; using System.Net; using System.Text; using System.Runtime.InteropServices; public class IcmpPing { [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)] private struct ICMP_OPTIONS { public byte Ttl; public byte Tos; public byte Flags; public byte OptionsSize; public IntPtr OptionsData; } [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)] private struct ICMP_ECHO_REPLY { public int Address; public int Status; public int RoundTripTime; public short DataSize; public short Reserved; public IntPtr DataPtr; public ICMP_OPTIONS Options; [MarshalAs(UnmanagedType.ByValTStr, SizeConst=9900)] public string Data; } [DllImport("Iphlpapi.dll", SetLastError = true)] private static extern IntPtr IcmpCreateFile(); [DllImport("Iphlpapi.dll", SetLastError = true)] private static extern bool IcmpCloseHandle(IntPtr handle); [DllImport("Iphlpapi.dll", SetLastError = true)] private static extern int IcmpSendEcho2Ex(IntPtr icmpHandle, IntPtr hEvent, IntPtr apcRoutine, IntPtr apcContext, int sourceAddress, int destinationAddress, string requestData, short requestSize, ref ICMP_OPTIONS requestOptions, ref ICMP_ECHO_REPLY replyBuffer, int replySize, int timeout); public bool PingStatus(IPAddress sourceIp, IPAddress destIp, int dataSize) { IntPtr icmpHandle = IcmpCreateFile(); ICMP_OPTIONS icmpOptions = new ICMP_OPTIONS(); icmpOptions.Ttl = 255; icmpOptions.Flags = 0x02; ICMP_ECHO_REPLY icmpReply = new ICMP_ECHO_REPLY(); string sData = CreateSendData(dataSize); int replies = IcmpSendEcho2Ex(icmpHandle, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, BitConverter.ToInt32(sourceIp.GetAddressBytes(), 0), BitConverter.ToInt32(destIp.GetAddressBytes(), 0), sData, (short)sData.Length, ref icmpOptions, ref icmpReply, Marshal.SizeOf(icmpReply), 30); IcmpCloseHandle(icmpHandle); if (replies > 0) { if (icmpReply.DataSize != dataSize) { return false; } return true; } return false; } public int PingRTT(IPAddress sourceIp, IPAddress destIp, int dataSize) { IntPtr icmpHandle = IcmpCreateFile(); ICMP_OPTIONS icmpOptions = new ICMP_OPTIONS(); icmpOptions.Ttl = 255; icmpOptions.Flags = 0x02; ICMP_ECHO_REPLY icmpReply = new ICMP_ECHO_REPLY(); string sData = CreateSendData(dataSize); int replies = IcmpSendEcho2Ex(icmpHandle, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, BitConverter.ToInt32(sourceIp.GetAddressBytes(), 0), BitConverter.ToInt32(destIp.GetAddressBytes(), 0), sData, (short)sData.Length, ref icmpOptions, ref icmpReply, Marshal.SizeOf(icmpReply), 30); IcmpCloseHandle(icmpHandle); if (replies > 0) { return icmpReply.RoundTripTime; } return -1; } private string CreateSendData(int length) { var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; var random = new Random(); StringBuilder builder = new StringBuilder(); for(int index = 0; index < length; index++) { builder.Append(chars[random.Next(chars.Length)]); } return builder.ToString(); } } "@ $pingStatus = [ICMPPing]::new() if ($RTT) { return ($pingStatus.PingRTT($Source, $Destination, $Size)) } else { return ($pingStatus.PingStatus($Source, $Destination, $Size)) } } #endregion if (-Not($Reliability)) { [int] $lastKnownGood = -1 if ((Start-Ping -Destination $Destination -Source $Source -Size $StartBytes)) { # update LKG $lastKnownGood = $StartBytes # last failed ping size $lastFailed = $EndBytes # next ping will be somewhere between start and end [int]$nextPing = [math]::Round(($EndBytes - $StartBytes) / 2, 0) # controls whether we found the MTU or not $MtuFound = $false :FindMTU while (-NOT $MtuFound) { do { Write-Verbose "nextPing: $nextPing, LKG: $lastKnownGood, LF: $lastFailed" $PingTest = Start-Ping -Destination $Destination -Source $Source -Size $nextPing if ($PingTest) { $failedCounter = 0 } else { $failedCounter = $failedCounter + 1 } } until ($PingTest -or $failedCounter -gt 3) # make payload smaller if (-NOT $PingTest) { # save the failed ping size $lastFailed = $nextPing # find the nextPing $nextPing = [math]::Round(($nextPing + $lastKnownGood) / 2, 0) if ($nextPing -ge $lastKnownGood) { $nextPing = [math]::Round(($lastFailed + $nextPing) / 2, 0) } Write-Verbose "NextPing: $nextPing" } else { # ping worked, but we're not done; make payload larger $LKG = $nextPing $nextPing = [math]::Round(($lastFailed + $lastKnownGood) / 2, 0) if ($nextPing -le $lastKnownGood) { $nextPing = [math]::Round(($lastFailed + $nextPing) / 2, 0) } $lastKnownGood = $LKG Write-Verbose "NextPing: $nextPing" } Write-Verbose "LastFailed: $lastFailed `n`n" # we should reach a point where nextping should be LKG + 1... then we're done if ($nextPing -eq $lastKnownGood) { $MtuFound = $true Write-Verbose "All done!" } } } if ($lastKnownGood -ne -1) { <# MTU = Payload + headers MSS = Payload ICMP headers are: Ethernet = 14 Bytes IP = 20 Bytes ICMP = 8 Bytes Total = 42 Bytes #> $obj = New-Object -TypeName psobject $obj | Add-Member -MemberType NoteProperty -Name Connectivity -Value $true $obj | Add-Member -MemberType NoteProperty -Name MSS -Value $lastKnownGood $obj | Add-Member -MemberType NoteProperty -Name MTU -Value $($lastKnownGood + 42) return $obj } else { # ping failed for some reason Write-Verbose "There were no successful pings. Please make sure ping (ICMP Echo) is permitted to $Destination." $obj = New-Object -TypeName psobject $obj | Add-Member -MemberType NoteProperty -Name Connectivity -Value $false $obj | Add-Member -MemberType NoteProperty -Name MSS -Value '0' $obj | Add-Member -MemberType NoteProperty -Name MTU -Value '0' return $obj } } else { # If we already know the MTU, we can send a bunch at that size to see how reliable the link is $ICMPResponse = @() $testCompleted = 0 $startTime = [System.DateTime]::Now do { #Specify the RTT Switch. We'll use this for more stuff later. $ICMPResponse += Start-Ping -Source $Source -Destination $Destination -Size $StartBytes -RTT } until([System.DateTime]::Now -ge $startTime.AddSeconds($testTime)) Return $ICMPResponse } } |