WINSOCK Examples

[José Roca]

 
Windows Sockets 2 (Winsock) enables programmers to create advanced Internet, intranet, and other network-capable applications to transmit application data across the wire, independent of the network protocol being used. With Winsock, programmers are provided access to advanced Microsoft® Windows® networking capabilities such as multicast and Quality of Service (QoS).

Winsock follows the Windows Open System Architecture (WOSA) model; it defines a standard service provider interface (SPI) between the application programming interface (API), with its exported functions and the protocol stacks. It uses the sockets paradigm that was first popularized by Berkeley Software Distribution (BSD) UNIX. It was later adapted for Windows in Windows Sockets 1.1, with which Windows Sockets 2 applications are backward compatible. Winsock programming previously centered around TCP/IP. Some programming practices that worked with TCP/IP do not work with every protocol. As a result, the Windows Sockets 2 API adds functions where necessary to handle several protocols.

[José Roca]

The getaddrinfo function provides protocol-independent translation from an ANSI host name to an address.

The following code example shows how to use the getaddrinfo function.

Code Select Expand


' ########################################################################################
' Demonstrates the use of the getaddrinfo Winsock function.
' Adapted from code posted by Pierre Bellisle in the PowerBASIC forum:
' http://www.powerbasic.com/support/pbforums/showthread.php?t=35760&highlight=Ai_FlagsToString
' ########################################################################################

#COMPILE EXE
#DIM ALL

#INCLUDE ONCE "ws2tcpip.inc"
#INCLUDE ONCE "iphlpapi.inc"
#INCLUDE ONCE "wsrm.inc"

' ========================================================================================
FUNCTION Ai_FlagsToString (BYVAL ai_flags AS DWORD) AS STRING

   LOCAL strBuffer AS STRING

   IF ai_flags THEN
      IF (ai_flags AND %AI_PASSIVE)     THEN strBuffer = "AI_PASSIVE"
      IF (ai_flags AND %AI_CANONNAME)   THEN strBuffer = strBuffer & " AI_CANONNAME"
      IF (ai_flags AND %AI_NUMERICHOST) THEN strBuffer = strBuffer & " AI_NUMERICHOST"
      IF (ai_flags AND %AI_ADDRCONFIG)  THEN strBuffer = strBuffer & " AI_ADDRCONFIG"
      IF (ai_flags AND %AI_SECURE)      THEN strBuffer = strBuffer & " AI_SECURE"
      IF (ai_flags AND %AI_RETURN_PREFERRED_NAMES) THEN
         strBuffer = strBuffer & " AI_RETURN_PREFERRED_NAMES"
      END IF
      FUNCTION = LTRIM$(strBuffer)
   ELSE
      FUNCTION = "AI_NONE"
   END IF

END FUNCTION
' ========================================================================================

' ========================================================================================
FUNCTION Ai_FamilyToString (BYVAL ai_family AS DWORD) AS STRING

   SELECT CASE ai_family
      CASE %AF_UNSPEC  : FUNCTION = "AF_UNSPEC"
      CASE %AF_INET    : FUNCTION = "AF_INET"
      CASE %AF_NETBIOS : FUNCTION = "AF_NETBIOS"
      CASE %AF_INET6   : FUNCTION = "AF_INET6"
      CASE %AF_IRDA    : FUNCTION = "AF_IRDA"
      CASE %AF_BTH     : FUNCTION = "AF_BTH"
      CASE ELSE        : FUNCTION = "AF_UNKNOWN" & STR$(ai_family)
   END SELECT

END FUNCTION
' ========================================================================================

' ========================================================================================
FUNCTION Ai_SocktTypeToString (BYVAL ai_sockttype AS DWORD) AS STRING

   SELECT CASE ai_sockttype
      CASE %SOCK_STREAM    : FUNCTION = "SOCK_STREAM"
      CASE %SOCK_DGRAM     : FUNCTION = "SOCK_DGRAM"
      CASE %SOCK_RAW       : FUNCTION = "SOCK_RAW"
      CASE %SOCK_RDM       : FUNCTION = "SOCK_RDM"
      CASE %SOCK_SEQPACKET : FUNCTION = "SOCK_SEQPACKET"
      CASE ELSE            : FUNCTION = "SOCK_UNKNOWN" & STR$(ai_sockttype)
   END SELECT

END FUNCTION
' ========================================================================================

' ========================================================================================
FUNCTION Ai_ProtocolToString (BYVAL ai_protocol AS DWORD) AS STRING

   SELECT CASE ai_protocol
      CASE 0            : FUNCTION = "IPPROTO_ZERO"   ' Not_IPv4_nor_IPv6
      CASE %IPPROTO_TCP : FUNCTION = "IPPROTO_TCP"
      CASE %IPPROTO_UDP : FUNCTION = "IPPROTO_UDP"
      CASE %IPPROTO_RM  : FUNCTION = "IPPROTO_RM"
      CASE ELSE         : FUNCTION = "IPPROTO_UNKNOWN" & STR$(ai_protocol)
   END SELECT

END FUNCTION
' ========================================================================================

' ========================================================================================
FUNCTION ipDwordToDot (BYVAL ip AS DWORD) AS STRING

   LOCAL pByte AS BYTE PTR

   pByte = VARPTR(ip)
   FUNCTION = USING$("#_.#_.#_.#", @pByte, @pByte[1], @pByte[2], @pByte[3])

END FUNCTION
' ========================================================================================

' ========================================================================================
FUNCTION Memo (BYVAL strTxtDef AS STRING, BYVAL strTxtVar AS STRING) AS STRING

   STATIC strBuffer AS STRING

   strBuffer = strBuffer & strTxtDef & $TAB & strTxtVar & $CRLF
   REPLACE $NUL WITH "." IN strBuffer
   FUNCTION = strBuffer

END FUNCTION
' ========================================================================================

' ========================================================================================
' Main
' ========================================================================================
FUNCTION PBMAIN () AS LONG

   LOCAL WsaInfo     AS WsaData
   LOCAL lResult     AS LONG
   LOCAL szNodeName  AS ASCIIZ * %MAX_HOSTNAME_LEN
   LOCAL szServName  AS ASCIIZ * %SNLEN
   LOCAL hints       AS ADDRINFO
   LOCAL pRes        AS ADDRINFO PTR
   LOCAL pAi_Addr_In AS SOCKADDR_IN PTR
   LOCAL pAi_Addr    AS SOCKADDR PTR
   LOCAL strBuffer   AS STRING

   szNodeName    = "microsoft.com"   ' Microsoft.com or ip 67.17.204.214
   'szNodeName    = "ibm.com"
   'szNodeName    = "powerbasic.com"
   szServName    = "http"   ' Either a service name or port number. FTP-21, HTTP-80

   WSAStartUp %WINSOCK_VERSION, WsaInfo

   MSGBOX "Status: " & WsaInfo.szSystemStatus

   lResult = getaddrinfo(szNodeName, szServName, hints, pRes)

   Memo "szNodeName:         ", (szNodeName)
   Memo "szServName:         ", (szServName)
   Memo "Error:              ", AfxWinErrMsg(lResult)   ' Success returns zero. Failure returns a nonzero Windows Sockets error code

   IF lResult = %ERROR_SUCCESS THEN
      DO
         Memo " ", $CRLF
         Memo "addr info pointer: ", HEX$(pRes)
         Memo "flags:             ", Ai_FlagsToString(@pRes.ai_flags)
         Memo "family:            ", Ai_FamilyToString(@pRes.ai_family)
         Memo "sockttype:         ", Ai_sockttypeToString(@pRes.ai_socktype)
         Memo "protocol:          ", Ai_ProtocolToString(@pRes.ai_protocol)
         Memo "canonical-addr:    ", HEX$(@pRes.ai_canonname)
         IF @pRes.ai_canonname THEN
            Memo "canonical-string:  ", (@pRes.@ai_canonname)
         END IF
         Memo "addrlen:           ", FORMAT$(@pRes.ai_addrlen)
         pAi_Addr = @pRes.ai_addr
         Memo "addr-sa-family:    ", Ai_FamilyToString((@pAi_Addr.sa_family))
         IF @pAi_Addr.sa_family = %AF_INET THEN
            pAi_Addr_In = @pRes.ai_addr
            Memo "addr-sin-family:   ", Ai_FamilyToString((@pAi_Addr_In.sin_family))
            Memo "addr-sin-port:     " , FORMAT$(@pAi_Addr_In.sin_port)
            Memo "addr-sin-addr:     ", ipDwordToDot(@pAi_Addr_In.sin_addr.s_addr)
            Memo "addr-sin-zero:     ", (@pAi_Addr_In.sin_zero)
         ELSE
            Memo "addr-sa-family:    ", Ai_FamilyToString((@pAi_Addr.sa_family))
            Memo "addr-sa-data:      ", (@pAi_Addr.sa_data)
         END IF
         Memo "next addr info:    ", HEX$(@pRes.ai_next)
         pRes = @pRes.ai_next
      LOOP UNTIL pRes = 0
   END IF

   freeaddrinfo BYVAL pRes
   WSACleanUp

   MessageBox %HWND_DESKTOP, BYCOPY Memo("", ""), "getaddrinfo", %MB_ICONINFORMATION OR %MB_OK

END FUNCTION
' ========================================================================================