Re: [lwip-users] Problems with sending UDP packets in FreeRTOS

[Mike Fleetwood]

Hi Sylvain,

Thanks for your "useful" input.

If you read what I posted, you will see that I didn't write the code snippet included.  It was a quick-and-dirty copy from some demo code in a link that Noam posted.  As I said elsewhere, my code does check that each function completes successfully before continuing.  And, yes, I did spot that it uneccessarily (but harmless) includes the terminating "null" on the end of the string.

If, by "low level netif driver" you mean the ethernet adaptor interface driver - that was provided by ST, and is the latest version they offer - I'm not aware of any reported problems with it.  Everything on top of that is LWIP.

Regards,
Mike.

On 28/07/2016 11:16, Sylvain Rochet wrote:

Hi Mike,

On Thu, Jul 28, 2016 at 10:52:50AM +0100, Mike Fleetwood wrote:

I tried one of Noam's linked examples (included below) - but that showed
exactly the same problem, stopped sending after about 20 minutes (I couldn't
tell if it was ERR_USE again, but no reason to think it was any different!).

Well, given how much the snippet below is defective, I assume your whole 
software quality is between poor to critically wrong. Given that, the 
bug is probably in your low level netif driver.

void udp_test2(void *arg)
{
  struct netconn *conn;
  char  msg[]="testing" ;
  struct  netbuf *buf;
  char  * data;

  conn = netconn_new( NETCONN_UDP );

Woah, you REALLY HAVE TO check if netconn_new returns a non NULL conn.

  netconn_bind(conn, IP_ADDR_ANY, 1234 ); //local port

You also have to check if netconn_bind actually worked…

  netconn_connect(conn, IP_ADDR_BROADCAST, 1235 );

You also have to check if netconn_connect actually worked…

  for( ;; )
  {
    buf = netbuf_new();

Woah, you REALLY HAVE TO check if netbuf_new returns a non NULL buf.

    data =""  sizeof(msg));

Woah, you REALLY HAVE TO check if netbuf_alloc returns a non NULL data.

    memcpy (data, msg, sizeof (msg));

You probably wanted to use sizeof(msg)-1 and not sizeof(msg) here, given 
you wanted to send a static string.

    netconn_send(conn, buf);
    netbuf_delete(buf);  // De-allocate packet buffer

    osDelay(4);  //some delay!
  }
}

Dear god.


Sylvain

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