Monday, August 31, 2009

How do I write an ActiveX Ping Object?

I provide the source code first, and I will explain it later:

Hello

VERSION 5.00
Begin VB.UserControl PingObj 
   ClientHeight    =   3600
   ClientLeft      =   0
   ClientTop       =   0
   ClientWidth     =   4800
   InvisibleAtRuntime=   -1  'True
   ScaleHeight     =   3600
   ScaleWidth      =   4800
   Windowless      =   -1  'True
End
Attribute VB_Name = "PingObj"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Private Const IP_SUCCESS As Long = 0
Private Const IP_STATUS_BASE As Long = 11000
Private Const IP_BUF_TOO_SMALL As Long = (11000 + 1)
Private Const IP_DEST_NET_UNREACHABLE As Long = (11000 + 2)
Private Const IP_DEST_HOST_UNREACHABLE As Long = (11000 + 3)
Private Const IP_DEST_PROT_UNREACHABLE As Long = (11000 + 4)
Private Const IP_DEST_PORT_UNREACHABLE As Long = (11000 + 5)
Private Const IP_NO_RESOURCES As Long = (11000 + 6)
Private Const IP_BAD_OPTION As Long = (11000 + 7)
Private Const IP_HW_ERROR As Long = (11000 + 8)
Private Const IP_PACKET_TOO_BIG As Long = (11000 + 9)
Private Const IP_REQ_TIMED_OUT As Long = (11000 + 10)
Private Const IP_BAD_REQ As Long = (11000 + 11)
Private Const IP_BAD_ROUTE As Long = (11000 + 12)
Private Const IP_TTL_EXPIRED_TRANSIT As Long = (11000 + 13)
Private Const IP_TTL_EXPIRED_REASSEM As Long = (11000 + 14)
Private Const IP_PARAM_PROBLEM As Long = (11000 + 15)
Private Const IP_SOURCE_QUENCH As Long = (11000 + 16)
Private Const IP_OPTION_TOO_BIG As Long = (11000 + 17)
Private Const IP_BAD_DESTINATION As Long = (11000 + 18)
Private Const IP_ADDR_DELETED As Long = (11000 + 19)
Private Const IP_SPEC_MTU_CHANGE As Long = (11000 + 20)
Private Const IP_MTU_CHANGE As Long = (11000 + 21)
Private Const IP_UNLOAD As Long = (11000 + 22)
Private Const IP_ADDR_ADDED As Long = (11000 + 23)
Private Const IP_GENERAL_FAILURE As Long = (11000 + 50)
Private Const MAX_IP_STATUS As Long = (11000 + 50)
Private Const IP_PENDING As Long = (11000 + 255)
Private Const PING_TIMEOUT As Long = 500
Private Const WS_VERSION_REQD As Long = &H101
Private Const MIN_SOCKETS_REQD As Long = 1
Private Const SOCKET_ERROR As Long = -1
Private Const INADDR_NONE As Long = &HFFFFFFFF
Private Const MAX_WSADescription As Long = 256
Private Const MAX_WSASYSStatus As Long = 128

Public Type ICMP_OPTIONS
    Ttl             As Byte
    Tos             As Byte
    Flags           As Byte
    OptionsSize     As Byte
    OptionsData     As Long
End Type

Private Type ICMP_ECHO_REPLY
    Address         As Long
    Status          As Long
    RoundTripTime   As Long
    DataSize        As Long 'formerly integer
   'Reserved        As Integer
    DataPointer     As Long
    Options         As ICMP_OPTIONS
    Data            As String * 250
End Type

Private Type WSADATA
   wVersion As Integer
   wHighVersion As Integer
   szDescription(0 To MAX_WSADescription) As Byte
   szSystemStatus(0 To MAX_WSASYSStatus) As Byte
   wMaxSockets As Long
   wMaxUDPDG As Long
   dwVendorInfo As Long
End Type

Private Declare Function IcmpCreateFile Lib "icmp.dll" () As Long

Private Declare Function IcmpCloseHandle Lib "icmp.dll" _
   (ByVal IcmpHandle As Long) As Long
   
Private Declare Function IcmpSendEcho Lib "icmp.dll" _
   (ByVal IcmpHandle As Long, _
    ByVal DestinationAddress As Long, _
    ByVal RequestData As String, _
    ByVal RequestSize As Long, _
    ByVal RequestOptions As Long, _
    ReplyBuffer As ICMP_ECHO_REPLY, _
    ByVal ReplySize As Long, _
    ByVal Timeout As Long) As Long
    
Private Declare Function WSAGetLastError Lib "wsock32" () As Long

Private Declare Function WSAStartup Lib "wsock32" _
   (ByVal wVersionRequired As Long, _
    lpWSADATA As WSADATA) As Long
    
Private Declare Function WSACleanup Lib "wsock32" () As Long

Private Declare Function gethostname Lib "wsock32" _
   (ByVal szHost As String, _
    ByVal dwHostLen As Long) As Long
    
Private Declare Function gethostbyname Lib "wsock32" _
   (ByVal szHost As String) As Long

Private Declare Sub CopyMemory Lib "kernel32" _
   Alias "RtlMoveMemory" _
  (xDest As Any, _
   xSource As Any, _
   ByVal nbytes As Long)
   
Private Declare Function inet_addr Lib "wsock32" _
   (ByVal s As String) As Long
Private ECHO As ICMP_ECHO_REPLY
Dim StatusCode As String
Dim Address As String
Dim RTT As Long
Dim Size As Long
Dim ReceiveData As String
Dim Pointer As Long

Public Function Ping(IPAddress, Content)
   Dim pos As Long
   Dim success As Long
   If SocketsInitialize() Then
     'ping the IP by passing the address,
     'text to send, and the ECHO structure.
      success = Pinging((IPAddress), (Content), ECHO)
     'display the results
      StatusCode = GetStatusCode(success)
      Address = "" & ECHO.Address
      RTT = ECHO.RoundTripTime
      Size = ECHO.DataSize
      If Left$(ECHO.Data, 1) <> Chr$(0) Then
         pos = InStr(ECHO.Data, Chr$(0))
         ReceiveData = Left$(ECHO.Data, pos - 1)
      End If
      Pointer = ECHO.DataPointer
      SocketsCleanup
   End If
   Ping = StatusCode
End Function

Public Function GetStatusCode(Status As Long) As String

   Dim msg As String
   
   Select Case Status
      Case IP_SUCCESS:               msg = "ip success"
      Case INADDR_NONE:              msg = "inet_addr: bad IP format"
      Case IP_BUF_TOO_SMALL:         msg = "ip buf too_small"
      Case IP_DEST_NET_UNREACHABLE:  msg = "ip dest net unreachable"
      Case IP_DEST_HOST_UNREACHABLE: msg = "ip dest host unreachable"
      Case IP_DEST_PROT_UNREACHABLE: msg = "ip dest prot unreachable"
      Case IP_DEST_PORT_UNREACHABLE: msg = "ip dest port unreachable"
      Case IP_NO_RESOURCES:          msg = "ip no resources"
      Case IP_BAD_OPTION:            msg = "ip bad option"
      Case IP_HW_ERROR:              msg = "ip hw_error"
      Case IP_PACKET_TOO_BIG:        msg = "ip packet too_big"
      Case IP_REQ_TIMED_OUT:         msg = "ip req timed out"
      Case IP_BAD_REQ:               msg = "ip bad req"
      Case IP_BAD_ROUTE:             msg = "ip bad route"
      Case IP_TTL_EXPIRED_TRANSIT:   msg = "ip ttl expired transit"
      Case IP_TTL_EXPIRED_REASSEM:   msg = "ip ttl expired reassem"
      Case IP_PARAM_PROBLEM:         msg = "ip param_problem"
      Case IP_SOURCE_QUENCH:         msg = "ip source quench"
      Case IP_OPTION_TOO_BIG:        msg = "ip option too_big"
      Case IP_BAD_DESTINATION:       msg = "ip bad destination"
      Case IP_ADDR_DELETED:          msg = "ip addr deleted"
      Case IP_SPEC_MTU_CHANGE:       msg = "ip spec mtu change"
      Case IP_MTU_CHANGE:            msg = "ip mtu_change"
      Case IP_UNLOAD:                msg = "ip unload"
      Case IP_ADDR_ADDED:            msg = "ip addr added"
      Case IP_GENERAL_FAILURE:       msg = "ip general failure"
      Case IP_PENDING:               msg = "ip pending"
      Case PING_TIMEOUT:             msg = "ping timeout"
      Case Else:                     msg = "unknown  msg returned"
   End Select
   
   GetStatusCode = CStr(Status) & "   [ " & msg & " ]"
   
End Function

Private Function Pinging(sAddress As String, _
                     sDataToSend As String, _
                     ECHO As ICMP_ECHO_REPLY) As Long

  'If Ping succeeds :
  '.RoundTripTime = time in ms for the ping to complete,
  '.Data is the data returned (NULL terminated)
  '.Address is the Ip address that actually replied
  '.DataSize is the size of the string in .Data
  '.Status will be 0
  '
  'If Ping fails .Status will be the error code
   
   Dim hPort As Long
   Dim dwAddress As Long
   
  'convert the address into a long representation
   dwAddress = inet_addr(sAddress)
   
  'if a valid address..
   If dwAddress <> INADDR_NONE Then
   
     'open a port
      hPort = IcmpCreateFile()
      
     'and if successful,
      If hPort Then
      
        'ping it.
         Call IcmpSendEcho(hPort, _
                           dwAddress, _
                           sDataToSend, _
                           Len(sDataToSend), _
                           0, _
                           ECHO, _
                           Len(ECHO), _
                           PING_TIMEOUT)

        'return the status as ping succes and close
         Pinging = ECHO.Status
         Call IcmpCloseHandle(hPort)
      
      End If
      
   Else:
        'the address format was probably invalid
         Pinging = INADDR_NONE
         
   End If
  
End Function
   

Private Sub SocketsCleanup()
   
   If WSACleanup() <> 0 Then
       MsgBox "Windows Sockets error occurred in Cleanup.", vbExclamation
   End If
    
End Sub


Private Function SocketsInitialize() As Boolean

   Dim WSAD As WSADATA
   
   SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = IP_SUCCESS
    
End Function


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