/*
    Compiler: BC++ 3.1, 
              Turbo C++ 1.01 (3.01)
          
    Compile mode: large

    Project: main.C
             ..\..\..\lib\upac5000.lib
             ..\lib\tcp_dm32.lib

    The Dynamic Host Configuration Protocol (DHCP) provides configuration parameters to Internet hosts.
    DHCP consists of two components: a protocol for delivering host-specific configuration  parameters 
    from a DHCP server to a host and a mechanism for allocation of network addresses to hosts.

    DHCP is built on a client-server model, where designated DHCP server hosts allocate network addresses 
    and deliver configuration parameters to dynamically configured hosts.
    Throughout the remainder of this document, the term "server" refers to a host providing
    initialization

                Client                         Server
                  |                              |
          Begins initialization                  |
                  |                              |
                  |----------------------------->|
                  |         DHCPDISCOVER         |
                  |                          Determines
                  |                         configuration
                  |                              |
                  |<---------------------------- |
                  |           DHCPOFFER          |
                  |                              |
                  |                              |
                  |----------------------------->|
                  |          DHCPREQUEST         |
                  |                              |
                  |                    Commits configuration
                  |                              |
                  |<-----------------------------|
                  |            DHCPACK           |
                  |                              |
        Initialization complete                  |
                  |                              |
                  |----------------------------->|
                  |          DHCPRELEASE         |
                  |                        Discards lease
                  |               |              |
             Timeline diagram of messages exchanged between DHCP 
             client and servers when allocating a new network address

    Follow the steps below to get the information from DHCP server.
    Step1:
        Set 'bUseDhcp=1' to use the DHCP client function
    Step2:
        Declare the 3 variables for saving the new address.
        for using DHCP, Set the IP address/MASK to 0 before call Ninit().
    Step3:
        Set DhcpLeaseTime=100" 
        (100 means the desired length of lease time (Unit: sec))
    Step4
        Install_DHCP(); // must call Install_DHCP() for DHCP function to work. 
        Hardware: 7188E series

    Note:
        If the program NEED NOT the DHCP client functions, need not to call Install_DHCP(),
        then the codes for DHCP & DNS will not be link into the .exe file.

    For more details, refer to RFC1533 and RFC2131 for more details about DHCP options
        http://www.faqs.org/rfcs/rfc1533.html
        http://www.apps.ietf.org/rfc/rfc2131.html

    [Jan 28, 2015]
*/

#include <stdlib.h>
#include "..\..\..\lib\upac5000.h"
#include "..\..\lib\tcpip32.h"

extern struct NETDATA *NetHost, *NetGateway;

int Ethernet_Init(void)
{
    /*
    Return:
         0: ok.
        -1: function "llip" error
        -2: function "Ninit" error
        -3: function "Portinit" error
    */
    int iRet;
    struct ip host_ip;

    GetSavedIp((struct ip*) &host_ip);
    iRet=lhip("7186EX", &host_ip);
    if(iRet!=NoError)
        return -1;

    if(bUseDhcp)
    {
        // for using DHCP, Set the IP address, Mask and Gateway to 0 before call Ninit().
        *(long *) NetHost->Iaddr.c=
        *(long *) NetHost->Imask.c=
        *(long *) NetGateway->Iaddr.c=0L;
        
        DhcpLeaseTime=20;   // by default DhcpLeaseTime=0,
                            // that is the time is assigned by the DHCP server.
                            // the time unit is second.
        Install_DHCP();     // must call Install_DHCP() for DHCP function to work.
    }
    
    iRet=Ninit();
    if(iRet!=NoError)
        return -2;
    
    iRet=Portinit("*");     /* initiate network device */
    if(iRet<NoError)
    {
        Nterm();
        return -3;
    }

    return 0;
}

void main(void)
{
    STOPWATCH swDhcp;
    int iRet, Quit=0;

    InitLib();
    
    /* set bUseDhcp to 1 for enabling the DHCP client feature */
    bUseDhcp=1;
    
    if(bUseDhcp) {    
        *(long *) NetHost->Iaddr.c=
        *(long *) NetHost->Imask.c=
        *(long *) NetGateway->Iaddr.c=0L;
        
        DhcpLeaseTime=30;   /* set the DHCP lease time (in seconds) for IP addresses assigned to DHCP clients.
                               the default DHCP lease time is 0, meaning that the lease time depends on the DHCH server. */
        Install_DHCP();     // must call Install_DHCP() for DHCP function to work.
    }
    
    if((iRet=NetStart())!=NoError) {
        Print("Failed to initialize the network settings [%d].\n", iRet);
        return;
    }
    
    T_StopWatchStart(&swDhcp);  // start a timer for DHCP

    while(!Quit) {
        YIELD();
        
        if(nets[0].DHCPserver) {
            if(T_StopWatchGetTime(&swDhcp)>=nets[0].RenewalTime) {
                T_StopWatchStart(&swDhcp);
                
                iRet=DHCPget(0, DhcpLeaseTime);
                
                if(iRet>=0) {
                    Print("\nNew network settings are obtained from the DHCP server:\n");
                    Print("\tIP Address .... : %d.%d.%d.%d\n", NetHost->Iaddr.c[0], NetHost->Iaddr.c[1], NetHost->Iaddr.c[2], NetHost->Iaddr.c[3]);
                    Print("\tSubnet Mask ... : %d.%d.%d.%d\n", NetHost->Imask.c[0], NetHost->Imask.c[1], NetHost->Imask.c[2], NetHost->Imask.c[3]);
                    Print("\tGateway ....... : %d.%d.%d.%d\n", NetGateway->Iaddr.c[0], NetGateway->Iaddr.c[1], NetGateway->Iaddr.c[2], NetGateway->Iaddr.c[3]);;
                }
                else {
                    Print("Failed to obtain a vaild IP address from the DHCP server [%d]\n", iRet);
                }
            }
        }
        
        // press ESC key to exit
        if(Kbhit() && Getch()==27) {
            Quit=1;
        }
    }
    
    Nterm();
}