text: /*
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * This file is part of the Contiki operating system.
   *
   */
  
  #include "contiki.h"
  #include "contiki-lib.h"
  #include "contiki-net.h"
  #include "dev/leds.h"
  
  #include <string.h>
  
  #define DEBUG DEBUG_PRINT
  #include "net/ip/uip-debug.h"
  
  #define UIP_IP_BUF   ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
  
  #define MAX_PAYLOAD_LEN 120
  
  static struct uip_udp_conn *server_conn;
  
  PROCESS(udp_server_process, "UDP server process");
  PROCESS(led_process, "LED process");
  AUTOSTART_PROCESSES(&udp_server_process, &led_process);
  /*---------------------------------------------------------------------------*/
  static void
  tcpip_handler(void)
  {
    static int seq_id;
    char buf[MAX_PAYLOAD_LEN];
  
    if(uip_newdata()) {
      leds_toggle(LEDS_RED);
    
      ((char *)uip_appdata)[uip_datalen()] = 0;
      PRINTF("Server received: '%s' from ", (char *)uip_appdata);
      PRINT6ADDR(&UIP_IP_BUF->srcipaddr);
      PRINTF("\r\n");
  
      uip_ipaddr_copy(&server_conn->ripaddr, &UIP_IP_BUF->srcipaddr);
      PRINTF("Responding with message: ");
      sprintf(buf, "Hello from the server! (%d)", ++seq_id);
      PRINTF("%s\r\n", buf);
  
      uip_udp_packet_send(server_conn, buf, strlen(buf));
      /* Restore server connection to allow data from any node */
      memset(&server_conn->ripaddr, 0, sizeof(server_conn->ripaddr));
    }
  }
  /*---------------------------------------------------------------------------*/
  static void
  print_local_addresses(void)
  {
    int i;
    uint8_t state;
  
    PRINTF("Server IPv6 addresses: \r\n");
    for(i = 0; i < UIP_DS6_ADDR_NB; i++) {
      state = uip_ds6_if.addr_list[i].state;
      if(uip_ds6_if.addr_list[i].isused &&
         (state == ADDR_TENTATIVE || state == ADDR_PREFERRED)) {
        PRINT6ADDR(&uip_ds6_if.addr_list[i].ipaddr);
        PRINTF("\r\n");
      }
    }
  }
  /*---------------------------------------------------------------------------*/
  PROCESS_THREAD(udp_server_process, ev, data)
  {
  #if UIP_CONF_ROUTER
    uip_ipaddr_t ipaddr;
  #endif /* UIP_CONF_ROUTER */
  
    PROCESS_BEGIN();
    PRINTF("UDP server started\r\n");
  
  #if UIP_CONF_ROUTER
    uip_ip6addr(&ipaddr, 0xaaaa, 0, 0, 0, 0, 0, 0, 0);
    uip_ds6_set_addr_iid(&ipaddr, &uip_lladdr);
    uip_ds6_addr_add(&ipaddr, 0, ADDR_AUTOCONF);
  #endif /* UIP_CONF_ROUTER */
  
    print_local_addresses();
  
    server_conn = udp_new(NULL, UIP_HTONS(3001), NULL);
    udp_bind(server_conn, UIP_HTONS(3000));
  
    while(1) {
      PROCESS_YIELD();
      if(ev == tcpip_event) {
        tcpip_handler();
      }
    }
  
    PROCESS_END();
  }
  
  PROCESS_THREAD(led_process, ev, data)
  {
  	static struct etimer timer;
  	
  	PROCESS_BEGIN();
  
  	etimer_set(&timer, CLOCK_CONF_SECOND / 2);
    
  	for (;;) {
  		/* Wait on our timer */
  		PROCESS_WAIT_EVENT_UNTIL(ev == PROCESS_EVENT_TIMER);
  		
  		leds_toggle(LEDS_GREEN);
  		
  		/* reset the timer so we can wait on it again */
  		etimer_reset(&timer);
  	}
    
  	PROCESS_END();
  }
  
  /*---------------------------------------------------------------------------*/
  