Allowing user to choose DHCP or static IP

Hi,

I would like the users of my product to be able to choose whether they want to use DHCP or use a static IP address. The idea is to allow users to adjust the IP configuration using the front panel of the system I am developing. The IP address set-up in ecos works very well but the choice between DHCP and a static IP address is made in the ecos configuration tool and is then "hard-wired" into the project.

I have written a function based on init_all_network_interfaces (See below) which takes a parameter to specifiy whether to use DHCP or a static IP address (The static IP address is currently hard-coded in this function, but I will make it adjustable by the user later). This function actually works very well, but it has one bizarre piece of behaviour. If I call it with UseDHCP=true to get a dynamic IP address and then some time later call it with UseDHCP=false to set a static IP address then the system ends up responding to both the IP address assigned by DHCP and the static IP address. I can use a web browser to communicate with the system using either the old IP address or the new one. This can't be a good thing!

Is there a function I can call which will completely shut down the ethernet interface so that I can then restart it with a different IP address? I have tried this code without success:

my_init_all_network_interfaces(false);
dhcp_halt();
my_init_all_network_interfaces(true);

Here is the function I am using:

// This function replaces the one supplied by ecos: init_all_network_interfaces
// This version of the function allows DHCP to be dynamically switched on or off
//
void my_init_all_network_interfaces(cyg_bool_t UseDHCP)
{
  static volatile int in_my_init_all_network_interfaces = 0;
    
  cyg_scheduler_lock();
  while ( in_my_init_all_network_interfaces ) 
  {
    // Another thread is doing this...
    cyg_scheduler_unlock();
    cyg_thread_delay( 10 );
    cyg_scheduler_lock();
  }
  in_my_init_all_network_interfaces = 1;
  cyg_scheduler_unlock();
  if (UseDHCP) 
  {
    // Perform a complete initialization, using BOOTP/DHCP
    eth0_up = true;
    eth0_dhcpstate = 0; // Says that initialization is external to dhcp
    if (do_dhcp(eth0_name, &eth0_bootp_data, &eth0_dhcpstate, &eth0_lease)) 
    {
      show_bootp(eth0_name, &eth0_bootp_data);
    } 
    else 
    {
      diag_printf("BOOTP/DHCP failed on eth0\n");
      eth0_up = false;
    }
  }
  else
  {
    eth0_up = true;
    build_bootp_record(&eth0_bootp_data,
  eth0_name,
  "192.168.205.100",
  "255.255.252.0",
  "192.168.204.250",
  "192.168.204.250",
  "192.168.204.250");
    show_bootp(eth0_name, &eth0_bootp_data);
  }
  if (eth0_up) 
  {
    if (!init_net(eth0_name, &eth0_bootp_data)) 
    {
      diag_printf("Network initialization failed for eth0\n");
      eth0_up = false;
    }
  }
  // Open the monitor to other threads.
  in_my_init_all_network_interfaces = 0;
}

Mike