UDP listen does not read (TCP works fine)

[tsil]

Hi

UDP listen does not work, anyone can se what I am doing wrong ? (I have googled around but failed anyhow )

I have copied most of the code below from internet, it worked with TCP, the only thing I have changed for the UDP listen case is that
I replaced the two lines of the TCP part with the UDP part:
-----------------------------------------------------------------
'TCP
'm_Hints.ai_socktype = sock_type.SOCK_STREAM
'Server = "192.168.1.113"

'UDP
m_Hints.ai_socktype = sock_type.SOCK_DGRAM
Server = "10.81.32.131"
------------------------------------------------------------------

BR
/Erik

Option Explicit
' Constants ----------------------------------------------------------
Const INVALID_SOCKET = -1
Const WSADESCRIPTION_LEN = 256
Const SOCKET_ERROR = -1

' Typ definitions ----------------------------------------------------

Private Type WSADATA
wVersion As Integer
wHighVersion As Integer
szDescription(0 To WSADESCRIPTION_LEN) As Byte
szSystemStatus(0 To WSADESCRIPTION_LEN) As Byte
iMaxSockets As Integer
iMaxUdpDg As Integer
lpVendorInfo As Long
End Type

Private Type ADDRINFO
    ai_flags As Long
    ai_family As Long
    ai_socktype As Long
    ai_protocol As Long
    ai_addrlen As Long
    ai_canonName As LongPtr 'strptr
    ai_addr As LongPtr 'p sockaddr
    ai_next As LongPtr 'p addrinfo
End Type



' External functions --------------------------------------------------

Public Declare Function WSAStartup Lib "ws2_32.dll" (ByVal wVersionRequested As Integer, ByRef data As WSADATA) As Long
Public Declare Function Connect Lib "ws2_32.dll" Alias "connect" (ByVal socket As Long, ByVal SOCKADDR As Long, ByVal namelen As Long) As Long
Public Declare Sub WSACleanup Lib "ws2_32.dll" ()
Private Declare PtrSafe Function GetAddrInfo Lib "ws2_32.dll" Alias "getaddrinfo" (ByVal NodeName As String, ByVal ServName As String, ByVal lpHints As LongPtr, lpResult As LongPtr) As Long
Public Declare Function ws_socket Lib "ws2_32.dll" Alias "socket" (ByVal AF As Long, ByVal stype As Long, ByVal Protocol As Long) As Long
Public Declare Function closesocket Lib "ws2_32.dll" (ByVal socket As Long) As Long
Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Public Declare Function Send Lib "ws2_32.dll" Alias "send" (ByVal s As Long, ByRef buf As Any, ByVal buflen As Long, ByVal flags As Long) As Long
Public Declare Function SendWithPtr Lib "ws2_32.dll" Alias "send" (ByVal s As Long, ByVal bufPtr As Long, ByVal buflen As Long, ByVal flags As Long) As Long
Private Declare PtrSafe Function WSAGetLastError Lib "ws2_32.dll" () As Long
Private Declare Function VarPtrArray Lib "VBE7" Alias "VarPtr" (var() As Any) As Long
Private Declare Function recv Lib "wsock32.dll" (ByVal socket As Long, ByVal buffer As String, ByVal bufferLength As Long, ByVal flags As Long) As Long



Sub TestWinsock_UDP()
    Dim m_wsaData As WSADATA
    Dim m_RetVal As Integer
    Dim m_Hints As ADDRINFO
    Dim m_ConnSocket As Long: m_ConnSocket = INVALID_SOCKET
    Dim Server As String
    Dim port As String
    Dim pAddrInfo As LongPtr
    Dim RetVal As Long
    Dim lastError As Long

    Dim iResult As Integer

    RetVal = WSAStartup(MAKEWORD(2, 2), m_wsaData)
    If (RetVal <> 0) Then
        LogError "WSAStartup failed with error " & RetVal, WSAGetLastError()
        Call WSACleanup
        Exit Sub
    End If

    m_Hints.ai_family = AF.AF_UNSPEC
    

    'TCP
    'm_Hints.ai_socktype = sock_type.SOCK_STREAM
     'Server = "192.168.1.113"

    'UDP
    m_Hints.ai_socktype = sock_type.SOCK_DGRAM
    Server = "10.81.32.131"


    port = "55999"
    
    
    RetVal = GetAddrInfo(Server, port, VarPtr(m_Hints), pAddrInfo)
    If (RetVal <> 0) Then
        LogError "Cannot resolve address " & Server & " and port " & port & ", error " & RetVal, WSAGetLastError()
        Call WSACleanup
        Exit Sub
    End If

    
    m_Hints.ai_next = pAddrInfo
    Dim connected As Boolean: connected = False
    Do While m_Hints.ai_next > 0
        CopyMemory m_Hints, ByVal m_Hints.ai_next, LenB(m_Hints)

        m_ConnSocket = ws_socket(m_Hints.ai_family, m_Hints.ai_socktype, m_Hints.ai_protocol)

        If (m_ConnSocket = INVALID_SOCKET) Then
            
        Else
            Dim connectionResult As Long
            connectionResult = Connect(m_ConnSocket, m_Hints.ai_addr, m_Hints.ai_addrlen)

            If connectionResult <> SOCKET_ERROR Then
                connected = True
                Exit Do
            End If

            closesocket (m_ConnSocket)
        End If
    Loop

    


    If Not connected Then
        MsgBox "Fatal error: unable to connect to the server"
        Call WSACleanup
        Exit Sub
    End If


    Dim recvBuf(200) As Byte
    Dim recvbuflen As Integer
    recvbuflen = 10
    iResult = 1
    
    Do While iResult > 0
   
        iResult = recv(m_ConnSocket, recvBuf(0), recvbuflen, 0)
        If iResult > 0 Then
            MsgBox "Bytes received: " & iResult
        ElseIf iResult = 0 Then
            MsgBox "Connection closed"
        Else
            MsgBox "recv failed: " & WSAGetLastError()
        End If
   
    Loop
    

    RetVal = closesocket(m_ConnSocket)
    If RetVal <> 0 Then
    LogError "closesocket() failed", WSAGetLastError()
    Call WSACleanup
    Else
        Debug.Print "closed socket"
    End If
End Sub

Public Function MAKEWORD(Lo As Byte, Hi As Byte) As Integer
MAKEWORD = Lo + Hi * 256& Or 32768 * (Hi > 127)
End Function

Private Sub LogError(msg As String, Optional ErrorCode As Long = -1)
    If ErrorCode > -1 Then
        msg = msg & " (error code " & ErrorCode & ")"
    End If

    Debug.Print msg
End Sub

 

[tsil]

ah, solved it, just had to use bind instead of connect, now it works

 

[rs3hc]

Can I know what the code is just doing?
I'm a beginner which need help in a own project

Greetings ?