Networking (WinSock)

Don Freeman

Ok...I am REALLY getting frustrated trying to figure this out!!! >:( I am trying to create a client/server system that will be used in an upcoming game. I am trying to get the FD_xx options to work correctly. Can someone please take a look at this and tell me what (if anything) I am doing wrong? The problem I am getting now is when I run the server, then the client...The server picks up that the client has sent data. Good...it should. But when I go to READ that data...I get the WinSock error: 10014 - WSAEFAULT. The description from Microsoft's docs:
-------------------------------------------------------------------------------------
WSAFAULT (10014): Bad address.
The system detected an invalid pointer address in attempting to use a pointer argument of a call. This error occurs if an application passes an invalid pointer value, or if the length of the buffer is too small. For instance, if the length of an argument which is a struct sockaddr is smaller than sizeof(struct sockaddr).
-------------------------------------------------------------------------------------
[EDIT]
Also: I sometimes get:
WSAECONNABORTED
(10053)
Software caused connection abort.
An established connection was aborted by the software in your host machine, possibly due to a data transmission timeout or protocol error.
-------------------------------------------------------------------------------------
The client was not disconnected...it was still running! Does this mean this is a firewall issue? It is just (well should be) running on the local machine, so I don't see why that would be an issue...::)
I am probably missing something somewhere...but my eyes can't see it right now...please...anyone help? ::)

#SelectExpand
   1//////////////////////////////////////////////////////////////////////////////////////////////////
   2// <Main.cpp>
   3//////////////////////////////////////////////////////////////////////////////////////////////////
   4#define ALLEGRO_USE_CONSOLE
   5#include <allegro.h>
   6#include <winalleg.h>
   7//////////////////////////////////////////////////////////////////////////////////////////////////
   8#include <winsock.h>
   9#include <stdio.h>
  10//////////////////////////////////////////////////////////////////////////////////////////////////
  11#define BUFFERSIZE   255
  12//////////////////////////////////////////////////////////////////////////////////////////////////
  13int main( void )
  14{
//////////////////////////////////////////////////////////////////////////////////////////////
WORD        wsVersionRequested = MAKEWORD(1,1);
USHORT      iPort = 42479;
SOCKET      sListenSocket = INVALID_SOCKET;
SOCKET      sAcceptSocket = INVALID_SOCKET;
WSADATA     wsaData;
FD_SET      fdRead;
FD_SET      fdWrite;
ULONG       iNonBlocking  = 1;
char        iReuseAddress = 1;
DWORD       dwFlags = 0;
SOCKADDR_IN sInternetAddress;
SOCKADDR_IN sRemoteAddress;
int         iRemoteAddressLength = sizeof(sRemoteAddress);
//////////////////////////////////////////////////////////////////////////////////////////////
// [Network startup]
printf("Server...\n");
printf(" [Network]-><WSAStartup>->WinSock version(%i,%i)\n",LOBYTE(wsVersionRequested),
     HIBYTE(wsVersionRequested));
if ( WSAStartup(wsVersionRequested,&wsaData) != 0 )
{
  printf(" [Network]->Error!<WSAStartup>->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
if ( LOBYTE(wsaData.wVersion) != LOBYTE(wsVersionRequested) || 
   HIBYTE(wsaData.wVersion) != HIBYTE(wsVersionRequested) )
{
  printf(" [Network]->Error!<WSAStartup>->Error setting requested version!\n");
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
//////////////////////////////////////////////////////////////////////////////////////////////
// [Create listening socket]
printf(" [Network]->Attempting to create listening socket...\n");
sListenSocket = socket(PF_INET,SOCK_STREAM,0);
if ( sListenSocket == INVALID_SOCKET )
{
  printf(" [Network]->Error! Listening socket invalid!->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
//////////////////////////////////////////////////////////////////////////////////////////////
// [Set listening socket address]
printf(" [Network]->Setting listening socket address fields.");
sInternetAddress.sin_family        = AF_INET;
sInternetAddress.sin_addr.s_addr   = htonl(INADDR_ANY);
sInternetAddress.sin_port          = htons(iPort);
memset(sInternetAddress.sin_zero,'\0',8);
printf("Done.\n");
//////////////////////////////////////////////////////////////////////////////////////////////
// [Bind listening socket]
printf(" [Network]->Attempting to bind listening socket.\n");
if ( bind(sListenSocket,(struct sockaddr*)&sInternetAddress,
        sizeof(SOCKADDR_IN) ) != 0 )
{
  printf(" [Network]->Error binding listening socket!->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Closing listening socket.\n");
  closesocket(sListenSocket);
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
//////////////////////////////////////////////////////////////////////////////////////////////
printf(" [Network]->Setting listening socket to NON-BLOCKING mode.\n");
if( ioctlsocket(sListenSocket,FIONBIO,&iNonBlocking) == SOCKET_ERROR )
{
  printf(" [Network]->Error setting NON-BLOCKING mode!->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Closing listening socket.\n");
  closesocket(sListenSocket);
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
printf(" [Network]->Setting listening socket option->Reuse address mode.\n");
//if( ioctlsocket(sListenSocket,SO_REUSEADDR,&iReuseAddress) == SOCKET_ERROR  )
if( setsockopt(sListenSocket,SOL_SOCKET, SO_REUSEADDR, &iReuseAddress,
  sizeof(iReuseAddress)) == SOCKET_ERROR  )
{
  printf(" [Network]->Error setting SO_REUSEADDR mode!->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Closing listening socket.\n");
  closesocket(sListenSocket);
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
//////////////////////////////////////////////////////////////////////////////////////////////
printf(" [Network]->Attempt listen...\n");
if ( listen(sListenSocket,5) == SOCKET_ERROR )
{
  printf(" [Network]->Error listening!->%i\n",WSAGetLastError());
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Closing listening socket.\n");
  closesocket(sListenSocket);
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
//////////////////////////////////////////////////////////////////////////////////////////////
printf(" [Allegro]->Initialize system.\n");
allegro_init();
printf(" [Allegro]->Setting color depth.\n");
set_color_depth(32);
printf(" [Allegro]->Setting GFX mode.\n");
set_gfx_mode(GFX_AUTODETECT_WINDOWED,400,400,0,0);
printf(" [Allegro]->Setting color conversion.\n");
set_color_conversion(COLORCONV_TOTAL);
printf(" [Allegro]->Starting timer.\n");
install_timer();
printf(" [Allegro]->Starting keyboard service.\n");
install_keyboard();
printf(" [Allegro]->Starting mouse service.\n");
install_mouse();
//////////////////////////////////////////////////////////////////////////////////////////////
printf(" [Allegro]->Setting color depth.\n");
BITMAP *pBmp = create_bitmap(SCREEN_W,SCREEN_H);
if ( !pBmp )
{
  printf(" [Allegro]->Error creating buffer!\n");
  printf(" [System]->Shutdown started...\n");
  printf(" [Network]->Closing listening socket.\n");
  closesocket(sListenSocket);
  printf(" [Network]->Shutting down WinSock.\n");
  WSACleanup();
  printf(" [System]->Shut down.\n");
  printf("Goodbye! :)\n");
  return 1;
}
clear_bitmap(pBmp);
//////////////////////////////////////////////////////////////////////////////////////////////
printf(" [System]->Enter main loop.\n");
// SOCKET accept( SOCKET s, struct sockaddr FAR* addr,int FAR* addrlen );
while ( true )
{
  // [Network code]
  FD_ZERO(&fdRead);
  FD_ZERO(&fdWrite);
  timeval tv = { 0, 0 };
  // check for connection attempts
  sAcceptSocket = accept(sListenSocket,(struct sockaddr*)&sRemoteAddress,
                       &iRemoteAddressLength);
  if ( sAcceptSocket == INVALID_SOCKET )
  {
    int i = WSAGetLastError();
    if ( i == WSAEWOULDBLOCK )
    {
      //printf(" [Network]->Accept->Waiting for connections...\n");
    }
    else
    {
      printf(" [Network]->Accept->Error!->%i\n",i);
      break;
    }
  }
  else
  {
    FD_SET(sAcceptSocket,&fdRead);
    FD_SET(sAcceptSocket,&fdWrite);
    if ( select(0,&fdRead,&fdWrite,NULL,&tv ) == SOCKET_ERROR )
    {
      printf(" [Network]->Select error!->%i\n",WSAGetLastError());
    }
    else
    {
      printf(" [Network]->Select->OK.\n");
    }
    if ( FD_ISSET(sAcceptSocket,&fdRead) )
    {
      printf( " [Network]-><Remote>->Ready to receive data...\n");
    }
    if ( FD_ISSET(sAcceptSocket,&fdWrite) )
    {
      printf( " [Network]-><Remote>->Ready to send data...\n");
      char *cBuffer = NULL;
      DWORD dwTotalBytesReceived = recv(sAcceptSocket,cBuffer,BUFFERSIZE,0);
      if ( dwTotalBytesReceived == SOCKET_ERROR  )
      {
        printf(" [Network]->Error receiving data!->%i\n",WSAGetLastError());
      }
      else
      {
        printf(" [Network]-><Remote>->TotalSent->%i\n",dwTotalBytesReceived);
        if ( dwTotalBytesReceived > 0 )
        {
          printf(" [Network]-><Remote>->[Message]->%s\n",cBuffer);
        }
      }
    }
    //FD_CLR(sAcceptSocket,&fdRead);
    //FD_CLR(sAcceptSocket,&fdWrite);
  }
  closesocket(sAcceptSocket);
  // [Allegro code]
  if ( keypressed() )
  {
    if ( key[KEY_ESC] )
    {
      clear_keybuf();
      break;
    }
  }
  clear_bitmap(pBmp);
  textprintf(pBmp,font,0,SCREEN_H-text_height(font),makecol(255,255,255),
           "Press ESC key to exit...");
  blit(pBmp,screen,0,0,0,0,pBmp->w,pBmp->h);
}
printf(" [System]->Leaving main loop.\n");
//////////////////////////////////////////////////////////////////////////////////////////////
// [Cleanup]
printf(" [System]->Shutdown started...\n");
printf(" [Allegro]->Cleanup objects.\n");
destroy_bitmap(pBmp);
pBmp = NULL;
printf(" [Network]->Closing listening socket.\n");
closesocket(sListenSocket);
printf(" [Network]->Closing remote socket.\n");
closesocket(sAcceptSocket);
printf(" [Network]->Shutting down WinSock.\n");
WSACleanup();
printf(" [System]->Shut down.\n");
printf("Goodbye! :)\n");
//////////////////////////////////////////////////////////////////////////////////////////////
return 0;
//////////////////////////////////////////////////////////////////////////////////////////////
 260}
 261END_OF_MAIN()
 262//////////////////////////////////////////////////////////////////////////////////////////////////

Sorry for the long code...the actual working code is not that much...it is mainly all the verbose error checking code I put in...

The client binary is attached....(win32)
or clicky:
http://64.246.37.217/files/attachment/590432

The compiled server binary is attached also...(win32)
or clicky:
http://64.246.37.217/files/attachment/590433

Thanks in advance,
Donald 8-)

ReyBrujo

You use select to check whether you need to accept a new connection, or receive data. You are accepting when there is no need to do that. The code is complex because you did not do it in the standard way, were you using select to multiplex the information from the socket, it would be easier

Don Freeman

Basically what you are saying is that I should use something like this:

1[MAIN LOOP]
 select(...)
 if ( select tells me pending connection )
 {
    accept(...)
    if ( accepted sock valid )
    {
       process accepted socket
    }
    else
    {
       socket was invalid
    }
 }
 do other stuff
16[/MAIN LOOP]

Pseudo code (of course)...::)

Only question:
How do I know when select will return the connection attempt?

Thanks for your quick response,
Donald

ReyBrujo

Yes. I will tell you to check this again. When the connection is attempted, FD_ISSET will return true when you check the socket where you are listening. If FD_ISSET returns true in a socket that has already been accepted, then you are going to receive information.

    /*  check if the descriptor set is our listening one  */
    if (FD_ISSET(descriptor , &input)) {
        sockets[sockets_index] = accept(descriptor, NULL, NULL);
        /*  more code about accepting  */
    }
    /*  one of the sockets is sending data. Find it  */
    else {
        /*  receive information from a socket  */
    }

Note that descriptor is the socket at which you did listen.

Don Freeman

Ok...Thanks man! It just gets frustrating after awhile...I didn't want to ask for help, but it looks like I needed to anyway...

The FD_xx is what was confusing for me... My docs are kind of hard to follow about how to use them correctly...

Thanks again,
Donald

Thread #588389. Printed from Allegro.cc

1	[MAIN LOOP]
2	select(...)
3	if ( select tells me pending connection )
4	{
5	accept(...)
6	if ( accepted sock valid )
7	{
8	process accepted socket
9	}
10	else
11	{
12	socket was invalid
13	}
14	}
15	do other stuff
16	[/MAIN LOOP]