#include "uip.h"#include "uip_arp.h"#include "network-device.h"#include "httpd.h"#include "timer.h"#define BUF ((struct uip_eth_hdr *)&uip_buf[0])/*---------------------------------------------------------------------------*/intmain(void){  int i;  uip_ipaddr_t ipaddr;  struct timer periodic_timer, arp_timer;    timer_set(&periodic_timer, CLOCK_SECOND / 2);  timer_set(&arp_timer, CLOCK_SECOND * 10);    network_device_init();  uip_init();  uip_ipaddr(ipaddr, 192,168,0,2);  uip_sethostaddr(ipaddr);  httpd_init();    while(1) {    uip_len = network_device_read();    if(uip_len > 0) {      if(BUF->type == htons(UIP_ETHTYPE_IP)) {	uip_arp_ipin();	uip_input();	/* If the above function invocation resulted in data that	   should be sent out on the network, the global variable	   uip_len is set to a value > 0. */	if(uip_len > 0) {	  uip_arp_out();	  network_device_send();	}      } else if(BUF->type == htons(UIP_ETHTYPE_ARP)) {	uip_arp_arpin();	/* If the above function invocation resulted in data that	   should be sent out on the network, the global variable	   uip_len is set to a value > 0. */	if(uip_len > 0) {	  network_device_send();	}      }    } else if(timer_expired(&periodic_timer)) {      timer_reset(&periodic_timer);      for(i = 0; i < UIP_CONNS; i++) {	uip_periodic(i);	/* If the above function invocation resulted in data that	   should be sent out on the network, the global variable	   uip_len is set to a value > 0. */	if(uip_len > 0) {	  uip_arp_out();	  network_device_send();	}      }#if UIP_UDP      for(i = 0; i < UIP_UDP_CONNS; i++) {	uip_udp_periodic(i);	/* If the above function invocation resulted in data that	   should be sent out on the network, the global variable	   uip_len is set to a value > 0. */	if(uip_len > 0) {	  uip_arp_out();	  network_device_send();	}      }#endif /* UIP_UDP */            /* Call the ARP timer function every 10 seconds. */      if(timer_expired(&arp_timer)) {	timer_reset(&arp_timer);	uip_arp_timer();      }    }  }  return 0;}/*---------------------------------------------------------------------------*/