Need advise on my WSA TCP functions [C]

[matwachich]

Hi everybody!

I wanted to learn winsockets, and for this, I try to reproduce AutoIt's TCP functions.

My code is working pretty good!

I juste want somebody, an AutoIt dev, to look my code and tell me if I'm doing something wrong, or something need to be done differently.

Another problem, is that when I close a socket on one side of a connection, the recv functions in the other side doesn't detect the close action! (like TCPRecv would return an @error)

Thanks in advance!

(I compile it with GCC 4x)

Here is the code

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#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif

#define WINVER 0x0501
#define _WIN32_WINNT 0x0501

#include <windows.h>

#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>

#include <stdio.h>
#include <stdlib.h>

/* -------------------------------------------------------------------------- */

#define SIMPLE_TCP_BUILD_DLL
#include "simpletcp.h"

/* -------------------------------------------------------------------------- */

#define CHECK_INIT if (_global_ == NULL) return;
#define CHECK_INIT_RET(ret) if (_global_ == NULL) return ret;

#define SET_ERR(func) sprintf(_global_->err_func, "%s", func); _global_->err = WSAGetLastError();
#define UNSET_ERR sprintf(_global_->err_func, "%s", ""); _global_->err = 0;

/* -------------------------------------------------------------------------- */

typedef struct {
    WSADATA wsaData;
    char err_func[20];
    int err;
} simple_tcp_t;

simple_tcp_t* _global_ = NULL;

/* -------------------------------------------------------------------------- */
/* Standard functions */

/** \brief
 *
 * \return
 */
int     SIMPLE_TCP  TCPStartup ()
{
    if (_global_ != NULL) { return 1; }

    _global_ = malloc(sizeof(simple_tcp_t));
    if (_global_ == NULL) { return 0; }

    if (WSAStartup(MAKEWORD(2, 2), &_global_->wsaData) != 0) {
        free(_global_);
        _global_ = NULL;
        return 0;
    }

    UNSET_ERR

    return 1;
}


/** \brief
 *
 * \return
 */
void    SIMPLE_TCP  TCPShutdown ()
{
    if (_global_ == NULL) { return; }

    WSACleanup();
    free(_global_);
    _global_ = NULL;
}


/** \brief
 *
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPGetError (char* err_func, const size_t err_func_len)
{
    CHECK_INIT_RET(0)
    int err = _global_->err;
    if (err_func != NULL && err_func_len > 0) {
        snprintf(err_func, err_func_len, "%s", _global_->err_func);
    }
    UNSET_ERR
    return err;
}


/** \brief
 *
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPConnect (const char* host, const char* port)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    struct addrinfo hints, *result = NULL;
    ZeroMemory(&hints, sizeof(hints));

    hints.ai_family = AF_INET; // IP v4
    hints.ai_socktype = SOCK_STREAM; // Stream socket
    hints.ai_protocol = IPPROTO_TCP; // TCP

    if (getaddrinfo(host, port, &hints, &result) != 0) {
        SET_ERR("getaddrinfo")
        return 0;
    }

    SOCKET ConnectSocket = INVALID_SOCKET;
    ConnectSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (ConnectSocket == INVALID_SOCKET) {
        freeaddrinfo(result);
        SET_ERR("socket")
        return 0;
    }

    if (connect(ConnectSocket, result->ai_addr, (int)result->ai_addrlen) != 0) {
        freeaddrinfo(result);
        SET_ERR("connect")
        return 0;
    }
    freeaddrinfo(result);

    unsigned long mode = 1;
    if (ioctlsocket(ConnectSocket, FIONBIO, &mode) != 0) {
        SET_ERR("ioctlsocket")
        return 0;
    }

    return ConnectSocket;
}


/** \brief
 *
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPListen (const char* port)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    struct addrinfo hints, *result = NULL;
    ZeroMemory(&hints, sizeof(hints));

    hints.ai_family = AF_INET; // IP v4
    hints.ai_socktype = SOCK_STREAM; // Stream socket
    hints.ai_protocol = IPPROTO_TCP; // TCP
    hints.ai_flags = AI_PASSIVE; // this + node = NULL => local host IP

    if (getaddrinfo(NULL, port, &hints, &result) != 0) {
        SET_ERR("getaddrinfo")
        return 0;
    }

    SOCKET ListenSocket = INVALID_SOCKET;
    ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (ListenSocket == INVALID_SOCKET) {
        freeaddrinfo(result);
        SET_ERR("socket")
        return 0;
    }

    unsigned long mode = 1;
    if (ioctlsocket(ListenSocket, FIONBIO, &mode) != 0) {
        freeaddrinfo(result);
        SET_ERR("ioctlsocket")
        return 0;
    }

    if (bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen) != 0) {
        freeaddrinfo(result);
        SET_ERR("bind")
        return 0;
    }
    freeaddrinfo(result);

    if (listen(ListenSocket, SOMAXCONN) != 0) {
        SET_ERR("listen")
        return 0;
    }

    return ListenSocket;
}


/** \brief
 *
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPAccept (int socket)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    int err;
    SOCKET ClientSocket = INVALID_SOCKET;

    ClientSocket = accept(socket, NULL, NULL);
    err = WSAGetLastError();

    if (ClientSocket == INVALID_SOCKET && err != WSAEWOULDBLOCK) {
        SET_ERR("accept")
        return INVALID_SOCKET;
    }

    if (ClientSocket != INVALID_SOCKET) {
        unsigned long mode = 1;
        if (ioctlsocket(ClientSocket, FIONBIO, &mode) != 0) {
            SET_ERR("ioctlsocket")
            return INVALID_SOCKET;
        }
    }

    return ClientSocket;
}


/** \brief
 *
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPCloseSocket (int socket)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    if (shutdown(socket, SD_BOTH) != 0) {
        SET_ERR("shutdown")
        return 0;
    }

    if (closesocket(socket) != 0) {
        SET_ERR("closesocket")
        return 0;
    }

    return 1;
}


/** \brief
 *
 * \param
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPSend (int socket, const char* data, const size_t data_len)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    int ret = send(socket, data, data_len, 0);
    if ((ret == SOCKET_ERROR || ret == 0) && WSAGetLastError() != WSAEWOULDBLOCK) {
        SET_ERR("send")
        return 0;
    }

    return ret;
}


/** \brief
 *
 * \param
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPRecv (int socket, char* data, const size_t data_len)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    int ret = recv(socket, data, data_len, 0);
    if ((ret == 0 || ret == SOCKET_ERROR) && WSAGetLastError() != WSAEWOULDBLOCK) {
        SET_ERR("recv")
        return 0;
    }

    return ret;
}


/** \brief
 *
 * \param
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPNameToIP (const char* name, char* ip, const size_t ip_len)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    struct addrinfo hints, *result = NULL;
    ZeroMemory(&hints, sizeof(hints));

    hints.ai_family = AF_INET; // IP v4
    hints.ai_socktype = SOCK_STREAM; // Stream socket
    hints.ai_protocol = IPPROTO_TCP; // TCP

    if (getaddrinfo(name, NULL, &hints, &result) != 0) {
        SET_ERR("getaddrinfo")
        return 0;
    }

    if (result->ai_family != AF_INET || result->ai_addrlen != sizeof(struct sockaddr_in)) {
        SET_ERR("bad address family")
        freeaddrinfo(result);
        return 0;
    }

    struct sockaddr_in* addr = (struct sockaddr_in*)result->ai_addr;
    char* ret = inet_ntoa(addr->sin_addr);

    snprintf(ip, ip_len, "%s", ret);
    freeaddrinfo(result);

    return 1;
}


/** \brief
 *
 * \param
 * \param
 * \param
 *
 * \return
 */
int     SIMPLE_TCP  TCPSocketToIP (int socket, char* ip, const size_t ip_len)
{
    CHECK_INIT_RET(0)
    UNSET_ERR

    struct sockaddr_in addr_in;
    int len = sizeof(addr_in);

    if (getpeername(socket, (struct sockaddr*)&addr_in, &len) != 0) {
        SET_ERR("getpeername")
        return 0;
    }

    char* ret = inet_ntoa(addr_in.sin_addr);
    if (ret == NULL) {
        SET_ERR("inet_ntoa")
        return 0;
    }

    snprintf(ip, ip_len, "%s", ret);

    return 1;
}

and the header

#ifndef __SIMPLE_TCP_H__
#define __SIMPLE_TCP_H__

#ifdef SIMPLE_TCP_BUILD_DLL
#define SIMPLE_TCP __stdcall __declspec(dllexport)
#else
#define SIMPLE_TCP __stdcall __declspec(dllimport)
#endif

/* -------------------------------------------------------------------------- */
/* Standard functions */

int     SIMPLE_TCP  TCPStartup ();
void    SIMPLE_TCP  TCPShutdown ();

int     SIMPLE_TCP  TCPGetError (char* err_func, const size_t err_func_len);

int     SIMPLE_TCP  TCPConnect (const char* ip, const char* port);
int     SIMPLE_TCP  TCPListen (const char* port);
int     SIMPLE_TCP  TCPAccept (int socket);
int     SIMPLE_TCP  TCPCloseSocket (int socket);

int     SIMPLE_TCP  TCPSend (int socket, const char* data, const size_t data_len);
int     SIMPLE_TCP  TCPRecv (int socket, char* data, const size_t data_len);

int     SIMPLE_TCP  TCPNameToIP (const char* name, char* ip, const size_t ip_len);
int     SIMPLE_TCP  TCPSocketToIP (int socket, char* ip, const size_t ip_len);

#endif // __SIMPLE_TCP_H__

[funkey]

As far as I see you are just missing some timeouts.

I wrapped some C functions in AutoIt to extend the TCP functions of AutoIt.

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#include "socket_UDF.au3"

_WSAStartup()

Global $iSock = _socket($AF_INET, $SOCK_STREAM, $IPPROTO_TCP)
ConsoleWrite("Socket: " & $iSock & @CRLF)

Global $tTimeVal = DllStructCreate("DWORD timeout")
DllStructSetData($tTimeVal, "timeout", 200) ; Timeout 200ms

$iSockError = _setsockopt($iSock, $SOL_SOCKET, $SO_RCVTIMEO, $tTimeVal) ; set Timeout for recv
If $iSockError Then
    ConsoleWrite("SetSockOpt error setting recv timeout!. Windows Sockets Error Codes: " & _WSAGetLastError() & @CRLF)
    _closesocket($iSock)
    TCPShutdown() ;WSACleanup
EndIf

Global $iBind = _bind($iSock, @IPAddress1, 20000) ;local IP-Address and port to use
ConsoleWrite("Bind error: " & $iBind & @CRLF) ; 0 is OK

Global $iConnect = _connect($iSock, "10.1.6.51", 80)
ConsoleWrite("Connect error: " & $iConnect & @CRLF) ; 0 is OK

If $iConnect Then
    ConsoleWrite("Windows Sockets Error Codes: " & _WSAGetLastError() & @CRLF)
    _closesocket($iSock)
    TCPShutdown() ;WSACleanup
EndIf

Global $sToSend = "GET /input1?PW=?"
Global $tSendBuffer = DllStructCreate("char[" & StringLen($sToSend) & "]")
DllStructSetData($tSendBuffer, 1, $sToSend)

Global $iSend = _send($iSock, $tSendBuffer)
ConsoleWrite("Bytes sent: " & $iSend & @CRLF)

Global $tRecvBuffer = DllStructCreate("char[64]")
Global $iRecv = _recv($iSock, $tRecvBuffer)
ConsoleWrite("Bytes received: " & $iRecv & @CRLF)

ConsoleWrite("Data received: " & DllStructGetData($tRecvBuffer, 1) & @CRLF) ;input1;OFF

_closesocket($iSock)
_WSACleanup()

 

socket_UDF.au3

[matwachich]

Thanks for the answer!

Adding a timeout will not solve the problem, since my sockets are asynchronous.

I think it hase something to do with to SO_KEEPALIVE options, but I don't very well understand how it works or how to use it.

Edited May 18, 2013 by matwachich