[lwip-users] sending data from spartan3 to another

[devesh]

Hi all,

Thanks for previous responses!!

I have been facing a problem as I told earlier. I want to send an 2-D
array of 128X128 (say:char img[128][128]) from one Spartan board to
another. I am able to send 32bytes with the following code. But at
receiving end, I got 24bytes(8 bytes are being lost) only. When i
exceed from 32,I get nothing.
So I concluded that the max bytes can be transferred are 24. But how
can I send 128X128? Through loop?
Well, I am using RAW api of LWIP and edk on WinXP

//FROM SENDER
static err_t client_connected(void *arg, struct tcp_pcb *pcb, err_t err)
{
   int i;
   char test[32];
   //char *string = "Hello!";
   char LWIP_UNUSED_ARG(arg);

   for(i=0;i<32;i++)
   {
        test[i]='1';
   }
   test[i-9]='A';
   test[32]='\0';
   xil_printf("The Payload is %s \n\r",test);
   if (err != ERR_OK)

printf("\nclient_connected(): err argument not set to ERR_OK, but is
value is %d\n", err);

   else
   {
       tcp_sent(pcb, client_sent);
       tcp_write(pcb, test, strlen(test), 0);
   }

   return err;
}

//FROM RECEIVING SIDE
err_t recv_callback(void *arg, struct tcp_pcb *tpcb,
                               struct pbuf *p, err_t err)
{

        /* do not read the packet if we are not in ESTABLISHED state */
#if 0
        if (tpcb->state >= 5 && tpcb->state <= 8) {
                tcp_close(tpcb);
                if (p)
                        pbuf_free(p);
                //xil_printf("Connection (%d) closed\n\r", (int)(arg));
                return;
        } else if (tpcb->state > 8)
                return;
#else
        if (!p) {
                tcp_close(tpcb);
                tcp_recv(tpcb, NULL);
                return ERR_OK;
        }
#endif

        /* indicate that the packet has been received */
        tcp_recved(tpcb, p->len);
        int n=32;
        /* echo back the payload */
        /* in this case, we assume that the payload is < TCP_SND_BUF */
        if (tcp_sndbuf(tpcb) > p->len) {
                char testing[100];
                strncpy(testing, p->payload,p->len);
                testing[p->len]='\0';
                xil_printf("The actual Payload is %s\n\r",p->payload);
                xil_printf("The Payload is %s \n\r",testing);
                xil_printf("The Payload on %d is %c \n\r",n-9,testing[n-9]);
                xil_printf("The Reference is %d\n\r",p->ref);
                xil_printf("The Length of packet is %d\n\r",p->len);
                xil_printf("Remote Port Number :: %d\n\r",tpcb->remote_port);
                xil_printf("Local Port Number :: %d\n\r",tpcb->local_port);
                err = tcp_write(tpcb, p->payload, p->len, 1);
        } else
                print("no space in tcp_sndbuf\n\r");

        /* free the received pbuf */
        pbuf_free(p);

        return ERR_OK;
}

Now what I get:
on sender
Input string -
The Payload is : 1111111111111111111111A11111111

on receiver:
output -
The actual Payload is : 1111111111111111111111A
The Payload is : 111111111111111111111A
The Payload on 23 is A

I want to know what are the limitation of LWIP? And can size of
TCP_SND_BUF be changed?

Please help me out!!!
Regards,
Devesh