dtls-server.c

/*
 * 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 <string.h>

#include "config.h"

#ifndef DEBUG
#define DEBUG DEBUG_PRINT
#endif
#include "net/uip-debug.h"

#include "debug.h"
#include "dtls.h"

#define UIP_IP_BUF   ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
#define UIP_UDP_BUF  ((struct uip_udp_hdr *)&uip_buf[UIP_LLIPH_LEN])

#define MAX_PAYLOAD_LEN 120

static struct uip_udp_conn *server_conn;

static dtls_context_t *dtls_context;

int
read_from_peer(struct dtls_context_t *ctx, 
	       session_t *session, uint8 *data, size_t len) {
  size_t i;
  for (i = 0; i < len; i++)
    PRINTF("%c", data[i]);

  /* echo incoming application data */
  /* dtls_write(ctx, session, data, len); */
  return 0;
}

int
send_to_peer(struct dtls_context_t *ctx, 
	     session_t *session, uint8 *data, size_t len) {

  struct uip_udp_conn *conn = (struct uip_udp_conn *)dtls_get_app_data(ctx);

  uip_ipaddr_copy(&conn->ripaddr, &session->addr);
  conn->rport = session->port;

  uip_udp_packet_send(conn, data, len);

  /* Restore server connection to allow data from any node */
  memset(&conn->ripaddr, 0, sizeof(conn->ripaddr));
  memset(&conn->rport, 0, sizeof(conn->rport));

  return len;
}

int
get_psk_key(struct dtls_context_t *ctx, 
	    const session_t *session, 
	    const unsigned char *id, size_t id_len, 
	    const dtls_psk_key_t **result) {

  static const dtls_psk_key_t psk = {
    .id = (unsigned char *)"Client_identity", 
    .id_length = 15,
    .key = (unsigned char *)"secretPSK", 
    .key_length = 9
  };

  *result = &psk;
  return 0;
}

PROCESS(udp_server_process, "UDP server process");
AUTOSTART_PROCESSES(&udp_server_process);
/*---------------------------------------------------------------------------*/
static void
dtls_handle_read(dtls_context_t *ctx) {
  session_t session;

  if(uip_newdata()) {
    uip_ipaddr_copy(&session.addr, &UIP_IP_BUF->srcipaddr);
    session.port = UIP_UDP_BUF->srcport;
    session.size = sizeof(session.addr) + sizeof(session.port);
    
    dtls_handle_message(ctx, &session, uip_appdata, uip_datalen());
  }
}
/*---------------------------------------------------------------------------*/
static void
print_local_addresses(void)
{
  int i;
  uint8_t state;

  PRINTF("Server IPv6 addresses: \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("\n");
    }
  }
}

void
init_dtls() {
  static dtls_handler_t cb = {
    .write = send_to_peer,
    .read  = read_from_peer,
    .event = NULL,
    .get_psk_key = get_psk_key
  };
#if UIP_CONF_ROUTER
  uip_ipaddr_t ipaddr;
#endif /* UIP_CONF_ROUTER */

  PRINTF("DTLS server started\n");

#if 0  /* TEST */
  memset(&tmp_addr, 0, sizeof(linkaddr_t));
  if(get_eui64_from_eeprom(tmp_addr.u8));
#if NETSTACK_CONF_WITH_IPV6
  memcpy(&uip_lladdr.addr, &tmp_addr.u8, 8);
#endif
#endif /* TEST */

#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 */

  server_conn = udp_new(NULL, 0, NULL);
  udp_bind(server_conn, UIP_HTONS(20220));

  dtls_set_log_level(LOG_DEBUG);

  dtls_context = dtls_new_context(server_conn);
  if (dtls_context)
    dtls_set_handler(dtls_context, &cb);
}

/*---------------------------------------------------------------------------*/
PROCESS_THREAD(udp_server_process, ev, data)
{
  PROCESS_BEGIN();

  print_local_addresses();

  dtls_init();
  init_dtls();

  if (!dtls_context) {
    dsrv_log(LOG_EMERG, "cannot create context\n");
    PROCESS_EXIT();
  }

  while(1) {
    PROCESS_WAIT_EVENT();
    if(ev == tcpip_event) {
      dtls_handle_read(dtls_context);
    }
#if 0
    if (bytes_read > 0) {
      /* dtls_handle_message(dtls_context, &the_session, readbuf, bytes_read); */
      read_from_peer(dtls_context, &the_session, readbuf, bytes_read);
    }
    dtls_handle_message(ctx, &session, uip_appdata, bytes_read);
#endif
  }

  PROCESS_END();
}
/*---------------------------------------------------------------------------*/