adhoc networking programming

[charllychilly]

Hi I am actually programming an adhoc network in Visual C++ without success. please can anyone suggest what I can do or what I am doing wrong. this is my code.

#include <stdio.h>
#include <winsock.h>
#include <iostream.h>
#define ATTACH 100
#define DETACH 200
#define ECHO 300
#define TIME 400

const UINT SRV_UDP_PORT = 5050;

CSrvrView::CSrvrView()
{
                      m_hListenerThread = NULL;
                      int status;
                      WSADATA wsaData;
                      
                      m_data = "Initiallizing Windows Sockets DLL..."
                      if((status = WSAStartup(MAKEWORD(2,2), &wsaData)) == 0)
                      {
                                 m_data += "Succeeded\n";
                                 m_bInitialized = TRUE;
                                 }
                      else
                      {
                          m_bInitialized = FALSE;
                          }
                      m_data += "Creating socket...";               
//create socket
                      m_sock = socket(AF_INET, SOCK_DGRAM, 0);
                      
                      if (m_sock == INVALID_SOCKET)
                      {
                                 m_data += "Failed\n";
                                 }
                                 
//Bind socket to address
                     m_data =+ "Succeeded\nBinding socket..."            
// set up address structure
                    SOCKADDR_IN sa;
                    sa.sin_family = AF_INET;
                    sa.sin_addr.s_addr = htonl(INADDR_ANY);
                    sa.sin_port = htons(SRV_UDP_PORT);
                    
                    if(bind(m_sock,(PSOCKADDR)&sa, sizeof(sa)) == SOCKET_ERROR)
                    {
                                                   m_data += "Failed\n";
                                                   closesocket(m_sock);
                                                   }
                   m_data += "Succeeded\nCreating listener thread...";
                   unsigned long idThread;
                   m_hListenerThread = CreateThread(NULL,0,
                   (LPTHREAD_START_ROUTINE)Listener,
                   (void *)this, 0, &idThread);
                   
                   if(m_hListenerThread)
                   m_data += "Succeeded\nListening...\n";
                   else
                   m_data += "Failed\n";
                   }
//cleanup

CSrvrView::~CSrvrView()
{
                       if(m_bInitialized)
                       WSACleanup();
                       closesocket(m_sock);
                       if(m_hListenerThread)
                       ::TerminateThread(m_hListenerThread, 0);
                       
// define threads that recienves and process messages

long WINAPI Listener(CSrvrView* pView)
{
     SOCKADDR_IN saClnt;
     char msg[MSGSIZE];
     int saClntLen, nchar, msglen;
     
     while(1)
     {
             saClntLen = sizeof(saClnt);
             nchar = recvfrom(pView->m_sock, msg, MSGSIZE, 0
             (PSOCKADDR)&saClnt, &saClntLen);
             
             if(nchar < 0)
             {
                      pView->m_data += "Error in recvfrom\n";
                      pView->InvalidateRect(NULL);
                      }
            else
            {
                msglen = nchar;
                short *p_code = (short*)msg;
                short code = ntohs(*p_code);
                
                switch(code)
                {
                            case ATTACH:
                                 wsprintf(msg, "Client from %s attached\n",
                                 inet_ntoa(saClnt.sin_addr));
                                 msglen = strlen(msg);
                                 pView->m_data += msg;
                                 pView->InvalidateRect(NULL);
                                 break;
                                 
                            case DETACH:
                                 wsprintf(msg, "Client from %s detached\n",
                                 inet_ntoa(saClnt.sin_addr));
                                 msglen = strlen(msg);
                                 pView->m_data += msg;
                                 pView->InvalidateRect(NULL);
                                 break;
                                 
                            case TIME:
                                 time_t tnow;
                                 time(&tnow);
                                 sprintf(msg, "Time now: %s\n", ctime(&tnow));
                                 msglen = strlen(msg);
                                 break;
                                 
                            case ECHO:
                                 saClntLen = sizeof(saClnt);
                                 msglen = recvfrom(pView->m_sock, msg, MSGSIZE,
                                 0, (PSOCKADDR)&saClnt, &saClntLen);
                                 break;
                                 
                                 default:
                                         wsprintf(msg,
                                         "Don't understand message: %d\n",
                                         code);
                                         msglen = strlen(msg);
                                         
                                         }
                                         }

//send result to client

sendto(pView->m_sock, msg, msglen, 0, (PSOCKADDR)&saClnt, saClntLen);
}
return(0);
}

it is not even working.

[Andreas Masur]

[ Redirected thread ]

[MikeAThon]

... it is not even working.

Please elaborate. What "is not working"? Does it compile, for example? Does it run, but only badly? What does m_data look like (use the debugger to find out).

Incidentally, you are over-writing anything that might be received in the Listener thread's msg buffer. You receive data using

nchar = recvfrom(pView->m_sock, msg, MSGSIZE, 0
             (PSOCKADDR)&saClnt, &saClntLen);

and then you immediately over-write it using

wsprintf(msg, "Client from %s attached\n",
             inet_ntoa(saClnt.sin_addr));

You probably intended to use different buffers, so modify your code appropriately.

Mike