[lwip-users] DHCP usage with latest git code version

[Bram Peeters]

Hi,

 

What is the recommended sequence to start DHCP with the latest git sources (anno 20150910) ?

In the past dhcp_start() would automatically bring up the interface, and there is still a lot of references floating around to that way of working.

 

Eg in netif.c

/**

* Bring an interface up, available for processing

* traffic.

*

 * @note: Enabling DHCP on a down interface will make it come

* up once configured.

*

 * @see dhcp_start()

*/

void netif_set_up(struct netif *netif)

{

  if (!(netif->flags & NETIF_FLAG_UP)) {

    netif->flags |= NETIF_FLAG_UP;

 

 

So that note is wrong now because dhcp_start has an error  on a down interface:

err_t

dhcp_start(struct netif *netif)

{

  struct dhcp *dhcp;

  err_t result;

 

  LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);

  LWIP_ERROR("netif is not up, old style port?", netif_is_up(netif), return ERR_ARG;);

 

 

I have some stm cubemx generated code that says the following:

void LWIP_Init(void)

{

  tcpip_init( NULL, NULL );  

  ipaddr.addr = 0;

  netmask.addr = 0;

  gw.addr = 0;

 

 

  /* add the network interface */

  netif_add(&gnetif, &ipaddr, &netmask, &gw, NULL, &ethernetif_init, &tcpip_input);

 

  /*  Registers the default network interface */

  netif_set_default(&gnetif);

 

  if (netif_is_link_up(&gnetif))

  {

    /* When the netif is fully configured this function must be called */

    netif_set_up(&gnetif);

  }

  else

  {

    /* When the netif link is down this function must be called */

       netif_set_down(&gnetif);

  } 

  

 

dhcp_start(&gnetif);

...

}

 

But this appears incorrect (netif_is_link_up checks a flag that is set by netif_set_up, does not seem to make any sense at all in a chicken vs egg kind of way ??).

 

 

I tried the following in my polling loop which checks the phy for the link status:

            if ( regvalue & PHY_C1R_LINK_STATUS )
            {

                  /* Link detected */
                  tcpip_callback_with_block((tcpip_callback_fn) netif_set_link_up,
                                                             (void *) &g_sNetIF, 1);
                     
                /* Try to do it like this ?? */                   
                tcpip_callback_with_block((tcpip_callback_fn) dhcp_start,
                                                             (void *) &g_sNetIF, 1);

            }

But that still triggers the

  LWIP_ERROR("netif is not up, old style port?", netif_is_up(netif), return ERR_ARG;);

in dhcp_start.

 

Suggestions are welcome ...