Asynchronous sockets

Hmm done a lot of reserach on this, but still I cannot find out why this is failing...


Basically I have set up one test program to have one listening socket, and one client socket, I use Telnet to contact my test program, it works fine, has async sockets, and whenever I type it spits stuff onto the screen.

Now to the problem:

I have another program which uses an STL map to hold all the incoming sockets...

here's the relevant socket handling code..

Code:

---

HRESULT Cappsvr2View::socketMsg(WPARAM wp, LPARAM lp)
{
        if(WSAGETSELECTERROR(lp))
        {
                WSACleanup();
                TRACE0("Get select error, bailing out!");
                exit(1);
        }
        int recvd = 0;
        int sockNum = (int)wp;
        int tsockNum = 0;
        char * tmpbuf;
        char buf[100];
        ZeroMemory((void *)buf, 100);
        sockaddr_in clientSock;
        int lenclient = sizeof(clientSock);
        int errs = 0;
        CString tmp;
        LANCLIENT * tmpclient = new LANCLIENT;
        std::map<int, LANCLIENT*>::iterator it;

        switch(WSAGETSELECTEVENT(lp))
        {
                case FD_ACCEPT:
                        //AfxMessageBox("Client connecting!");
                        tmpclient->ClientSocket = accept(wp, (LPSOCKADDR)&clientSock, &lenclient);
                        errs = WSAAsyncSelect(tmpclient->ClientSocket, GetSafeHwnd(), WM_ONSOCKET, FD_WRITE | FD_READ | FD_CLOSE);
                        TRACE1("Error code for AsyncSelect is %d", errs);
                        if(INVALID_SOCKET == tmpclient->ClientSocket)
                        {
                                errs = WSAGetLastError();
                                TRACE1("ERROR: Socket error: %d\n", errs);
                                WSACleanup();
                        }
                        tmpclient->clnt_addr.sin_addr  = clientSock.sin_addr;
                        tmpclient->clnt_addr.sin_family = clientSock.sin_family;
                        tmpclient->clnt_addr.sin_port  = clientSock.sin_port;
                        tmpclient->currentMsg = "";
                        connections[(int)tmpclient->ClientSocket] = tmpclient;
                        TRACE2("Client Socket is %d and sockNum is %d\n",
                                connections[(int)tmpclient->ClientSocket]->ClientSocket, sockNum);
                       
                        TRACE1("Current sockets is %d", connections[(int)tmpclient->ClientSocket]->ClientSocket);
                        break;
                case FD_READ:               
                        recvd = recv((SOCKET)wp, buf, (int)strlen(buf), 0);
                        //TRACE2("Socket num is %d and wp is %d", connections[sockNum]->ClientSocket, (int)wp);
                        errs = WSAGetLastError();
                        //send(connections[sockNum]->ClientSocket, "welcome\n", (int)strlen("welcome\n"), 0);

                        if(recvd == SOCKET_ERROR)
                        {
                                recvd = WSAGetLastError();
                                TRACE1("Error with error code %d", recvd);
                        }
                        else if(errs == WSAEWOULDBLOCK)
                        {
                                TRACE0("Getting would block error!");
                        }
                        else if(recvd > 0)
                        {
                               
                                buf[recvd] = '\0';
                                tmpbuf = new char[(int)strlen(buf) + 1];
                                strcpy(tmpbuf, buf);
                                connections[sockNum]->currentMsg += tmpbuf;
                                TRACE1("We received %s", tmp);
                                //send(Clients[clientCount-1], tmpbuf, (int)strlen(tmpbuf), 0);
                                send(wp, tmpbuf, (int)strlen(tmpbuf), 0);
                                delete tmpbuf;
                                tmpbuf = NULL;
                        }
                        //AfxMessageBox(buf);
                        break;
                case FD_WRITE:
                        it = connections.begin();
                        while(it != connections.end())
                        {
                                send(it->second->ClientSocket, "Hello 2 you!\n", (int)strlen("Hello 2 you!\n"),0);
                                it++;
                        }
                        break;
                case FD_CLOSE:
                        AfxMessageBox("Client terminated connection!");
                        break;

                default:
                        break;
        }
        //delete tmpclient;
        //tmpclient = NULL;
        return 1;
}

---

here's the struct LANCLIENT

Code:

---

struct LANCLIENT
        {
                int InUse;
                SOCKET ClientSocket;
                struct sockaddr_in clnt_addr;
                CString currentMsg;
        };

---

I just lose the ability to talk with the telnet client when I use the map, perhaps I am being an idiot and not finding what I need to know, but all I wanted to do was accumulate what the telnet client typed for the moment, any help would be much appreciated, thanks!

Also whenever I type in the telnet client field, I get the FD_READ message, but it always contains 0 bytes when I do a recv... which I read means basically the connection is terminated.

recvd = recv((SOCKET)wp, buf, (int)strlen(buf), 0);

You've already Zeromemoried buf, so strlen is going to return zero - you're telling recv your buffer length is zero! Try

recvd = recv((SOCKET)wp, buf, sizeof(buf), 0);

Also, you don't need to zero the buffer - don't treat it like a c-string, because it's not - you'll run into problems (e.g. what if the client sends a null as part of the data?).

ahhh thanks :) I had read that you should always zeromemory it, but thats what I get for blindly following all forum advice :D that worked like a charm, I didn't realize that was the whole problem. Thanks a bunch :)

Not sure that's the whole problem, I haven't looked very hard :)

hehe well it certainly worked, and it makes sense... but I wasn't really thinking about it beforehand. however if you spot something glaringly bad or bad codewise feel free to let me know ;)