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Come pingare un IP partendo dall HostName in Visual Basic
** Come pingare un IP partendo dall'HostName in Visual Basic **
Anche questa volta, come nello scorso numero, parliamo di piccole applicazioni
scritte in Visual Basic.
La scorsa volta abbiamo visto come ricavare un Host Name da un IP Address, quest
a volta andiamo a pingare un Host Name.
Ritengo inutlie ripetere che il codice sotto riportato non Ë di mia propriet‡,
ma Ë di propriet‡ di Randy Birch- VBnet Network.
Non voglio prendermi nessun merito per una cosa che non ho fatto io,sto soltanto
riportando pari pari il suo codice su questa rivista, per favorire qualcuno che
magari non conosce la lingua, o che magari non ha voglia di sbattersi per andare
a cercare tutorial in giro per la rete.
Cominciamo con una piccola introduzione:
Quando abbiamo soltanto a disposizione l'Host Name, e dobbiamo eseguire un ping,
dobbiamo prima "tradurre" il nome dell'Host in un indirizzo IP numerico.
In questo esempio usiamo l'API del Winsock chiamata gethostbyname.
Il codice di base Ë stato tradotto dalla descrizione in C dell'MSDN Microsoft.
La funzione TextToIP Ë stata trovata invece in un newsgrop.
Il form deve, o almeno dovrebbe avere, questo aspetto:
_________________________________
| Ping IP by Host |
|_________________________________|
| __________ |
| HOST |__________| |<---Text1
| __________ |
| IP ADD |__________| |<---Text2
| __________ |
| SEND |__________| ______ |<---Text3
| | | |
| | PING | |<---Command1
| |______| |
| ___________ |
| Return Stats |___________| |<---Text4(0)
| ___________ |
| Address(dec) |___________| |<---Text4(1)
| ___________ |
| Round trip time |___________| |<---Text4(2)
| ___________ |
| Data Packet Size |___________| |<---Text4(3)
| ___________ |
| Data Returned |___________| |<---Text4(4)
| ___________ |
| Data Pointer |___________| |<---Text4(5)
|_________________________________|
________________________________________________________________________________
Nel form bisogna inserire un command button (command1),
tre text box (text1; text2; text3)
e sei text box in una matrice di controllo (text4(0) - text4(5))
Quindi inserite questo codice:
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Option Explicit
Private Sub Command1_Click()
Dim ECHO As ICMP_ECHO_REPLY
Dim pos As Long
Dim success As Long
Dim sIPAddress As String
If SocketsInitialize() Then
'converte l'Host Name in IP Address
sIPAddress = GetIPFromHostName(Text1.Text)
Text2.Text = sIPAddress
'pinga l'IP passando l'indirizzo, il testo
'da usare, e la ECHO structure
success = Ping(sIPAddress, (Text3.Text), ECHO)
'mostra i risultati
Text4(0).Text = GetStatusCode(success)
Text4(1) = ECHO.Address
Text4(2) = ECHO.RoundTripTime & " ms"
Text4(3) = ECHO.DataSize & " bytes"
If Left$(ECHO.Data, 1) <> Chr$(0) Then
pos = InStr(ECHO.Data, Chr$(0))
Text4(4) = Left$(ECHO.Data, pos - 1)
End If
Text4(5) = ECHO.DataPointer
SocketsCleanup
Else
MsgBox "Windows Sockets for 32 bit Windows " & _
"environments is not successfully responding."
End If
End Sub
________________________________________________________________________________
Inserite poi questo codice in un modulo BAS.
________________________________________________________________________________
Option Explicit
Private Const IP_STATUS_BASE As Long = 11000
Private Const IP_SUCCESS As Long = 0
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
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 Type ICMP_OPTIONS
Ttl As Byte
Tos As Byte
Flags As Byte
OptionsSize As Byte
OptionsData As Long
End Type
Public Type ICMP_ECHO_REPLY
Address As Long
status As Long
RoundTripTime As Long
DataSize As Long
'Reserved As Integer
DataPointer As Long
Options As ICMP_OPTIONS
Data As String * 250
End Type
Private Type HOSTENT
hName As Long
hAliases As Long
hAddrType As Integer
hLen As Integer
hAddrList As Long
End Type
Private Declare Function gethostbyname Lib "WSOCK32.DLL" _
(ByVal hostname 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 lstrlenA Lib "kernel32" _
(lpString As Any) As Long
Private Declare Function WSAStartup Lib "WSOCK32.DLL" _
(ByVal wVersionRequired As Long, _
lpWSADATA As WSADATA) As Long
Private Declare Function WSACleanup Lib "WSOCK32.DLL" () As Long
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 inet_addr Lib "WSOCK32.DLL" _
(ByVal s As String) As Long
Public Function Ping(sAddress As String, _
sDataToSend As String, _
ECHO As ICMP_ECHO_REPLY) As Long
Dim hPort As Long
Dim dwAddress As Long
dwAddress = inet_addr(sAddress)
If dwAddress <> INADDR_NONE Then
hPort = IcmpCreateFile()
If hPort Then
Call IcmpSendEcho(hPort, _
dwAddress, _
sDataToSend, _
Len(sDataToSend), _
0, _
ECHO, _
Len(ECHO), _
PING_TIMEOUT)
Ping = ECHO.status
Call IcmpCloseHandle(hPort)
End If 'If hPort
Else:
Ping = INADDR_NONE
End If
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
Public Function GetIPFromHostName(ByVal sHostName As String) As String
Dim nbytes As Long
Dim ptrHosent As Long
Dim ptrName As Long
Dim ptrAddress As Long
Dim ptrIPAddress As Long
Dim sAddress As String
sAddress = Space$(4)
ptrHosent = gethostbyname(sHostName & vbNullChar)
If ptrHosent <> 0 Then
ptrName = ptrHosent
ptrAddress = ptrHosent + 12
'get the IP address
CopyMemory ptrName, ByVal ptrName, 4
CopyMemory ptrAddress, ByVal ptrAddress, 4
CopyMemory ptrIPAddress, ByVal ptrAddress, 4
CopyMemory ByVal sAddress, ByVal ptrIPAddress, 4
GetIPFromHostName = IPToText(sAddress)
End If
End Function
Private Function IPToText(ByVal IPAddress As String) As String
IPToText = CStr(Asc(IPAddress)) & "." & _
CStr(Asc(Mid$(IPAddress, 2, 1))) & "." & _
CStr(Asc(Mid$(IPAddress, 3, 1))) & "." & _
CStr(Asc(Mid$(IPAddress, 4, 1)))
End Function
Public Sub SocketsCleanup()
If WSACleanup() <> 0 Then
MsgBox "Windows Sockets error occurred in Cleanup.", vbExclamation
End If
End Sub
Public Function SocketsInitialize() As Boolean
Dim WSAD As WSADATA
SocketsInitialize = WSAStartup(WS_VERSION_REQD, WSAD) = IP_SUCCESS
End Function
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