Step 1: Code Example for the Ethernet Interface

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This and other projects in the Code Examples section are published on our website under the name "test_dhcp_lib".

 

Here is a simple example of using DHCP on the Ethernet (net.) interface. Notice how the callback_dhcp_ok() procedure is implemented! This is a good illustration of the protracted explanation in the Operations Details topic (not that we think you will read it all).

Note also the use of the NET_AVAILABLE define. This comes from the platform. If the Ethernet interface is available on the currently selected platform, then NET_AVAILABLE is "1". Similarly, if the Wi-Fi interface is available, then WLN_AVAILABLE is "1". Using such defines you can create applications that will compile on any platform, as long as this platform has at least the Ethernet, or the Wi-Fi interface.

Here is a sample debug output we've got after running the code:

 

 

DHCP(net)> ---START---

DHCP(net)> TX discovery message

DHCP(net)> RX offer message

DHCP(net)> TX request message

DHCP(net)> RX confirmation message

DHCP(net)> ---OK(ip: 192.168.1.246, gateway: 192.168.1.1, netmask: 255.255.255.0, lease: 529200 sec.)---

 

 

note_warning-wt

If you are compiling on one of the "W" platforms (that is, platforms with Wi-Fi), then you need to disable the wln. object, or this project won't compile. Go Project -> Settings -> Customize and set Wi-Fi (wln.) object to "Disabled".

 

And here is the code itself...

 

global.tbh:

 

'DEFINES-------------------------------------------------------------

#define DHCP_DEBUG_PRINT 1 'to see debug output by the DHCP lib

 

'INCLUDES------------------------------------------------------------

include "sock\trunk\sock.tbh" 'this lib is necessary for the DHCP lib's operation

include "dhcp\trunk\dhcp.tbh"

 

 

main.tbs:

 

include "global.tbh"

 

'====================================================================

sub on_sys_init()

       #if NET_AVAILABLE

               dhcp_start(PL_SOCK_INTERFACE_NET,"","")

       #endif

end sub

 

'--------------------------------------------------------------------

sub on_sys_timer()

       dhcp_proc_timer()

end sub

 

'--------------------------------------------------------------------

sub on_sock_data_arrival()

       dhcp_proc_data()

end sub

 

 

device.tbs:

 

include "global.tbh"

 

'====================================================================

sub callback_dhcp_ok(renew as no_yes, interface as pl_sock_interfaces, byref ip as string, byref gateway_ip as string, byref netmask as string, lease_time as dword)

       dim f as byte

 

       #if NET_AVAILABLE

               if interface=PL_SOCK_INTERFACE_NET then

                       if renew=YES and net.ip<>ip then

                               'this is a lease renewal and the DHCP server has issues new IP

                               'it is better to reboot than deal with the implications of the changed IP

                               sys.reboot

                       end if

                       

                       if net.ip<>ip then

                               'no need to close sockets -- this is definitely NOT a renewal an the DHCP lib

                               'has already closed all socket connections on this interface prior to setting

                               'the IP to 0.0.0.0

                               net.ip=ip

                               net.gatewayip=gateway_ip

                               net.netmask=netmask

                       end if

               end if

       #endif

end sub

 

'--------------------------------------------------------------------

sub callback_dhcp_failure(interface as pl_sock_interfaces,failure_code as en_dhcp_status_codes)

end sub

 

'--------------------------------------------------------------------

sub callback_dhcp_pre_clear_ip(interface as pl_sock_interfaces)

end sub

 

'--------------------------------------------------------------------

sub callback_dhcp_pre_buffrq(required_buff_pages as byte)

end sub

 

'--------------------------------------------------------------------

sub callback_dhcp_buff_released()

end sub