[lwip-users] Asynchronous events.

[Nick Thomas]

Hi,

I am trying to implement a simple client program. I have got the simple
httpd server app working OK in lwip, and I can connect to it using a browser
on my PC, and I see my simple web page. So far so good.

But, now I would like to use lwip as a client, in order to get it to go to
an external website (not lwip based), and download the home page using the
"GET / HTTP/1.1\r\n\r\n" code.

I tried using the netconn_XXX, and netbuf_XXX commands, and couldn't get it
to work, it simply blocks in the netconn_recv() waiting for data.
Then I tried the sockets api call (which I am more familiar with) - like
this:

-- SNIP --

        int sd;
        struct sockaddr_in saddr;
        struct sockaddr_in local;
        int len, sent;
        char buffer[1024];

        sd = socket(AF_INET, SOCK_STREAM, 0);

        printf("nettest: got socket\r\n");

        /* prepare local address */
        memset(&local, 0, sizeof(local));
        local.sin_family = AF_INET;
        local.sin_port = htons(INADDR_ANY);
        local.sin_addr.s_addr = htonl(INADDR_ANY);

        /* Is this really necessary for a client program? */
        bind( sd, (struct sockaddr *)&local, sizeof(local) );

        memset(&saddr, 0, sizeof(saddr));
        saddr.sin_len = sizeof(saddr);
        saddr.sin_family = AF_INET;
        saddr.sin_addr.s_addr = inet_addr("192.168.0.100"); /* my local web 
server
*/
        saddr.sin_port = htons(80);     /* http server. */

        printf("nettest: server setup\r\n");

        connect( sd, (struct sockaddr *) &saddr, sizeof(saddr) );

        printf("nettest: connected\r\n");

        sent = send(sd, (void *)my_hdr, sizeof(my_hdr), 0);

        printf("nettest: sent %d bytes\r\n", sent);

        len = recv( sd, buffer, sizeof(buffer), 0 );

        printf("Received %d bytes\r\n", len); /* NEVER GETS HERE */

-- END --

I now see that the recv() call hangs. I suppose it is waiting for some data.

In the Win32 world I could us a call like:
iRc = WSAAsyncSelect( client.sock, hWnd, WM_WSASYNC,
FD_CONNECT|FD_READ|FD_CLOSE );

Which would provide a callback method to inform my app when some data
arrives. Is there anything like this in lwip?


Thanks in advance.

Regards

Nick
-----------------------------
Nick Thomas
Email: address@hidden