Author Topic: VBA Winsock  (Read 1266 times)

nector

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VBA Winsock
« on: November 09, 2021, 09:44:29 am »
I'm still having some challenges in both sending data and receiving using VBA sockets where Am a making a mistake?

Code: [Select]
Option Compare Database

Option Explicit

Dim x As Long
Dim RecvAscii As Long
Dim OpenSocket As Long
Dim count As Long
Public Const COMMAND_ERROR = -1
Public Const RECV_ERROR = -1
Public Const NO_ERROR = 0
Public socketId As Long
'This is the Winsock API definition file for Visual Basic


'Setup the variable type 'hostent' for the WSAStartup command
Type Hostent
h_name As Long
h_aliases As Long
h_addrtype As String * 2
h_length As String * 2
h_addr_list As Long
End Type
Public Const SZHOSTENT = 16

'Set the Internet address type to a long integer (32-bit)
Type in_addr
s_addr As Long
End Type

'A note to those familiar with the C header file for Winsock
'Visual Basic does not permit a user-defined variable type
'to be used as a return structure. In the case of the
'variable definition below, sin_addr must
'be declared as a long integer rather than the user-defined
'variable type of in_addr.
Type sockaddr_in
sin_family As Integer
sin_port As Integer
sin_addr As Long
sin_zero As String * 8
End Type


Public Const WSADESCRIPTION_LEN = 256
Public Const WSASYS_STATUS_LEN = 128
Public Const WSA_DescriptionSize = WSADESCRIPTION_LEN + 1
Public Const WSA_SysStatusSize = WSASYS_STATUS_LEN + 1

'Setup the structure for the information returned from
'the WSAStartup() function.
Type WSAData
wVersion As Integer
wHighVersion As Integer
szDescription As String * WSA_DescriptionSize
szSystemStatus As String * WSA_SysStatusSize
iMaxSockets As Integer
iMaxUdpDg As Integer
lpVendorInfo As String * 200
End Type

'Define socket return codes
Public Const INVALID_SOCKET = &HFFFF
Public Const SOCKET_ERROR = -1

'Define socket types
Public Const SOCK_STREAM = 1 'Stream socket
Public Const SOCK_DGRAM = 2 'Datagram socket

Public Const SOCK_RAW = 3 'Raw data socket
Public Const SOCK_RDM = 4 'Reliable Delivery socket
Public Const SOCK_SEQPACKET = 5 'Sequenced Packet socket

'Define address families
Public Const AF_UNSPEC = 0 'unspecified
Public Const AF_UNIX = 1 'local to host (pipes, portals)
Public Const AF_INET = 2 'internetwork: UDP, TCP, etc.
Public Const AF_IMPLINK = 3 'arpanet imp addresses
Public Const AF_PUP = 4 'pup protocols: e.g. BSP
Public Const AF_CHAOS = 5 'mit CHAOS protocols
Public Const AF_NS = 6 'XEROX NS protocols
Public Const AF_ISO = 7 'ISO protocols
Public Const AF_OSI = AF_ISO 'OSI is ISO
Public Const AF_ECMA = 8 'european computer manufacturers
Public Const AF_DATAKIT = 9 'datakit protocols
Public Const AF_CCITT = 10 'CCITT protocols, X.25 etc
Public Const AF_SNA = 11 'IBM SNA
Public Const AF_DECnet = 12 'DECnet
Public Const AF_DLI = 13 'Direct data link interface
Public Const AF_LAT = 14 'LAT
Public Const AF_HYLINK = 15 'NSC Hyperchannel
Public Const AF_APPLETALK = 16 'AppleTalk
Public Const AF_NETBIOS = 17 'NetBios-style addresses
Public Const AF_MAX = 18 'Maximum # of address families

'Setup sockaddr data type to store Internet addresses
Type sockaddr
sa_family As Integer
sa_data As String * 14
End Type
Public Const SADDRLEN = 16

'Declare Socket functions

Public Declare PtrSafe Function closesocket Lib "wsock32.dll" (ByVal s As Long) As Long
Public Declare PtrSafe Function Connect Lib "wsock32.dll" Alias "connect" (ByVals As Long, addr As sockaddr_in, ByVal namelen As Long) As Long
Public Declare PtrSafe Function htons Lib "wsock32.dll" (ByVal hostshort As Long) As Integer
Public Declare PtrSafe Function inet_addr Lib "wsock32.dll" (ByVal cp As String) As Long
Public Declare PtrSafe Function recv Lib "wsock32.dll" (ByVal s As Long, ByVal buf As Any, ByVal buflen As Long, ByVal flags As Long) As Long
Public Declare PtrSafe Function recvB Lib "wsock32.dll" Alias "recv" (ByVal s As Long, buf As Any, ByVal buflen As Long, ByVal flags As Long) As Long
Public Declare PtrSafe Function sendto Lib "wsock32.dll" (ByVal s As Long, ByRef buf() As Byte, ByVal buflen As Long, ByVal flags As Long, addr As sockaddr_in, ByVal tolen As Integer) As Long
Public Declare PtrSafe Function socket Lib "wsock32.dll" (ByVal af As Long, ByVal socktype As Long, ByVal protocol As Long) As Long
Public Declare PtrSafe Function WSAStartup Lib "wsock32.dll" (ByVal wVersionRequired As Long, lpWSAData As WSAData) As Long
Public Declare PtrSafe Function WSACleanup Lib "wsock32.dll" () As Long
Public Declare PtrSafe Function WSAUnhookBlockingHook Lib "wsock32.dll" () As Long
Public Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)
Public Function ConnectServer(ByVal hostname As String, ByVal PortNumber As Integer) As Integer

Dim StartUpInfo As WSAData
'Version 1.1 (1*256 + 1) = 257
'version 2.0 (2*256 + 0) = 512
'Get WinSock version
'Initialize Winsock DLL
x = WSAStartup(257, StartUpInfo)

Dim I_SocketAddress As sockaddr_in
Dim ipAddress As Long
ipAddress = inet_addr(hostname) '...........(1)
'Create a new socket
socketId = socket(AF_INET, SOCK_STREAM, 0) '
If socketId = SOCKET_ERROR Then '
MsgBox ("ERROR: socket = " + Str$(socketId)) '...........(2)
OpenSocket = COMMAND_ERROR '
GoTo end1
End If '
'Open a connection to a server
I_SocketAddress.sin_family = AF_INET '
I_SocketAddress.sin_port = htons(PortNumber) '...........(3)
I_SocketAddress.sin_addr = ipAddress '
I_SocketAddress.sin_zero = String$(8, 0) '
x = Connect(socketId, I_SocketAddress, Len(I_SocketAddress)) '
If socketId = SOCKET_ERROR Then '
        MsgBox ("ERROR: connect = " + Str$(x)) '..(4)
        OpenSocket = COMMAND_ERROR '
    Else
        OpenSocket = socketId
End If
end1:
End Function


Public Function RecData(dataBuf As String, ByVal maxLength As Integer) As Integer
Dim c As String * 1
Dim length As Integer
dataBuf = ""
While length < maxLength
DoEvents
count = recv(socketId, c, 1, 0)
If count < 1 Then '
RecvAscii = RECV_ERROR '............(1)
dataBuf = Chr$(0) '
GoTo EndRec
End If '
If c = Chr$(10) Then '
dataBuf = dataBuf + Chr$(0) '............(2)
RecvAscii = NO_ERROR '
GoTo EndRec
End If '
length = length + count '............(3)
dataBuf = dataBuf + c '
Wend
RecvAscii = RECV_ERROR
EndRec:
End Function

Public Sub Disconnect()
x = closesocket(socketId)
If x = SOCKET_ERROR Then MsgBox ("ERROR: closesocket = " + Str$(x))

'Shutdown Winsock DLL
x = WSACleanup()
End Sub

Function SendCommand(command As String, ByVal PortNumber As Integer, ByVal hostname As String) As Integer
Dim I_SocketAddress As sockaddr_in
Dim ipAddress As Long
Dim y(0 To 1023) As Byte
Dim i As Long
Dim yLen As Integer: yLen = 1024
    'convert ip address to an internet address
    ipAddress = inet_addr(hostname) '...........(1)
    I_SocketAddress.sin_family = AF_INET '
    I_SocketAddress.sin_port = htons(PortNumber) '...........(3)
    I_SocketAddress.sin_addr = ipAddress '
    I_SocketAddress.sin_zero = String$(8, 0) '
   
    For i = 1 To Len(command)
        y(i - 1) = Asc(Mid$(command, i, 1))
        'Debug.Print y(i - 1)
    Next i
    y(i + 1) = Null
    count = sendto(socketId, y, yLen, 0, I_SocketAddress, Len(I_SocketAddress))
    If count = SOCKET_ERROR Then
        MsgBox ("ERROR: send = " + Str$(count))
        SendCommand = COMMAND_ERROR
        Exit Function
    End If
    SendCommand = NO_ERROR
End Function



Jan Axelson

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Re: VBA Winsock
« Reply #1 on: November 09, 2021, 12:34:06 pm »
Please describe what happens when you attempt to send or receive data, including error messages or other debugging information.