Re: [lwip-users] TCP Callback

[Robert]

On Mon, 2 Jun 2003, David Haas wrote:
> >How can I get callbacks when the other side of the connection closes the tcp 
> >socket?

the "recv" callback is called with the next to last parm (struct pbuf*) ==
NULL when the far end closes the connection.

For example, here is the callback function I use for a telnet server:

------------------------------------------------------------------------
static err_t telnet_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, 
err_t err)
{
FILE *file;
int i;
unsigned char *c;
struct pbuf *q;

debug( 2, ("telnet_recv called\n"));
  
file = arg;

if(p == NULL) {     // this means the remote end closed the connection
    debug( 2, ("telnet_recv p is NULL\n"));
        close_conn(pcb, file);
        return ERR_OK;
        }

do {
        q = p;
        p = pbuf_dechain(q);
        for(i=0, c=q->payload; i < q->len; i++, c++) {
                cfifo_add( file->fifo, *c );
                }
        tcp_recved(pcb, q->len);      // indicate data has been received
        pbuf_free(q);                    // free up the buffer
        } while( p );
return ERR_OK;
}


-------------------------------------------------------------------

-- 
Best Regards,
Robert