Using WinSock
This module will allow you to create a WinSock connection, as well as resolve computernames to IPs and vice-versa.
Module
Option Explicit
Public Const SOCKET_ERROR = -1
Public Const AF_INET = 2
Public Const PF_INET = AF_INET
Public Const MAXGETHOSTSTRUCT = 1024
Public Const SOCK_STREAM = 1
Public Const MSG_PEEK = 2
Private Type SockAddr
sin_family As Integer
sin_port As Integer
sin_addr As String * 4
sin_zero As String * 8
End Type
Private Type T_WSA
wVersion As Integer
wHighVersion As Integer
szDescription(0 To 255) As Byte
szSystemStatus(0 To 128) As Byte
iMaxSockets As Integer
iMaxUdpDg As Integer
lpVendorInfo As Long
End Type
Dim WSAData As T_WSA
Type Inet_Address
Byte4 As String * 1
Byte3 As String * 1
Byte2 As String * 1
Byte1 As String * 1
End Type
Public IPStruct As Inet_Address
Public Type T_Host
h_name As Long
h_aliases As Long
h_addrtype As Integer
h_length As Integer
h_addr_list As Long
End Type
' KERNEL32.DLL funtions
Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (Dest As Any, Src As Any, ByVal cb&)
' WSOCK32.DLL functions
Declare Function gethostbyaddr Lib "wsock32.dll" (addr As Long, ByVal addr_len As Long, ByVal addr_type As Long) As Long
Declare Function inet_addr Lib "wsock32.dll" (ByVal addr As String) As Long
Declare Function GetHostByName Lib "wsock32.dll" Alias "gethostbyname" (ByVal HostName As String) As Long
Declare Function GetHostName Lib "wsock32.dll" Alias "gethostname" (ByVal HostName As String, HostLen As Long) As Long
Declare Function WSAStartup Lib "wsock32.dll" (ByVal a As Long, b As T_WSA) As Long
Declare Function WSACleanUp Lib "wsock32.dll" Alias "WSACleanup" () As Integer
Declare Function Socket Lib "wsock32.dll" Alias "socket" (ByVal afinet As Integer, ByVal socktype As Integer, ByVal protocol As Integer) As Long
Declare Function ConnectWinsock Lib "wsock32.dll" Alias "connect" (ByVal sock As Long, sockstruct As SockAddr, ByVal structlen As Integer) As Integer
Declare Function send Lib "wsock32.dll" (ByVal sock As Long, ByVal msg As String, ByVal msglen As Integer, ByVal flag As Integer) As Integer
Declare Function recv Lib "wsock32.dll" (ByVal sock As Long, ByVal msg As String, ByVal msglen As Integer, ByVal flag As Integer) As Integer
Declare Function htonl Lib "wsock32.dll" (ByVal a As Long) As Long
Declare Function ntohl Lib "wsock32.dll" (ByVal a As Long) As Long
Declare Function htons Lib "wsock32.dll" (ByVal a As Integer) As Integer
Declare Function ntohs Lib "wsock32.dll" (ByVal a As Integer) As Integer
Declare Function closesocket Lib "wsock32.dll" (ByVal sn As Long) As Integer
Function HostByName(sHost As String) As String
Dim s As String
Dim p As Long
Dim Host As T_Host
Dim ListAddress As Long
Dim ListAddr As Long
Dim Address As Long
s = String(64, 0)
sHost = sHost + Right(s, 64 - Len(sHost))
p = GetHostByName(sHost)
If p = SOCKET_ERROR Then
Exit Function
Else
If p <> 0 Then
CopyMemory Host.h_name, ByVal p, Len(Host)
ListAddress = Host.h_addr_list
CopyMemory ListAddr, ByVal ListAddress, 4
CopyMemory Address, ByVal ListAddr, 4
HostByName = InetAddrLongToString(Address)
Else
HostByName = "No DNS Entry"
End If
End If
End Function
Private Function InetAddrStringToLong(Address As String) As Long
InetAddrStringToLong = inet_addr(Address)
End Function
Private Function InetAddrLongToString(Address As Long) As String
CopyMemory IPStruct, Address, 4
InetAddrLongToString = CStr(Asc(IPStruct.Byte4)) + "." + CStr(Asc(IPStruct.Byte3)) + "." + CStr(Asc(IPStruct.Byte2)) + "." + CStr(Asc(IPStruct.Byte1))
End Function
Function HostByAddress(ByVal sAddress As String) As String
Dim lAddress As Long
Dim p As Long
Dim HostName As String
Dim Host As T_Host
lAddress = inet_addr(sAddress)
p = gethostbyaddr(lAddress, 4, PF_INET)
If p <> 0 Then
CopyMemory Host, ByVal p, Len(Host)
HostName = String(256, 0)
CopyMemory ByVal HostName, ByVal Host.h_name, 256
If HostName = "" Then HostByAddress = "Unable to Resolve Address"
HostByAddress = Left(HostName, InStr(HostName, Chr(0)) - 1)
Else
HostByAddress = "No DNS Entry"
End If
End Function
Private Function ResolveHost(sHost As String) As Long
Dim lAddress As Long
lAddress = InetAddrStringToLong(sHost)
If lAddress = SOCKET_ERROR Then
ResolveHost = inet_addr(HostByName(sHost))
Else
ResolveHost = lAddress
End If
End Function
Public Function WinsockConnect(ByVal m_RemoteHost As String, m_RemotePort As Long, iSocket As Long) As Boolean
Dim sock As SockAddr
Dim sRemoteIP As String
Dim x As Long
Dim bAddr(0 To 3) As Byte
Dim i As Integer
iSocket = Socket(AF_INET, SOCK_STREAM, 0)
If iSocket < 1 Then
WinsockConnect = False
Exit Function
End If
sRemoteIP = ""
sock.sin_family = AF_INET
x = ResolveHost(m_RemoteHost)
CopyMemory bAddr(0), x, 4
For i = 0 To 3
sRemoteIP = sRemoteIP & Chr(bAddr(i))
Next
sock.sin_addr = sRemoteIP
sock.sin_port = htons(m_RemotePort)
sock.sin_zero = String(8, 0)
If ConnectWinsock(iSocket, sock, Len(sock)) Then
WinsockConnect = False
Exit Function
End If
WinsockConnect = True
End Function
Public Sub WinsockInit()
WSAStartup &H101, WSAData
End Sub
Usage
Before use any function you have to initialize the winsock, once you have terminated the winsock section you must call the WSACleanUp function.
WinsockInit
MsgBox HostByAddress("126.125.81.3")
WSACleanUp
This function returns the host name of the computer with the specified IP address (126.125.81.3) on your network domain.
The HostByName function returns the IP address of the specified computer name, it's exactly the opposite of the HostByAddress function.
To create a Winsock connection with another Winsock use the WinsockConnect Function, specify the name (or IP address) of the host, the communication port and it will return you the connection ID in the iSocket parameter, use send and recv functions (with the returned iSocket parameter) to Send and Receive data from the Winsock connection.
Special Instructions
This code originally appeared on AndreaVB.com, and has been republished here with the permission of Andrea Tincani.
Loading Comments ...
Comments
No comments have been added for this post.
You must be logged in to make a comment.