dhcpc.c

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

/****************************************************************************
 * netutils/dhcpc/dhcpc.c
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <[e-mail]>
 *
 * Based heavily on portions of uIP:
 *
 *   Author: Adam Dunkels <[e-mail]>
 *   Copyright (c) 2005, Swedish Institute of Computer Science
 *   All rights reserved.
 *
 * 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.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <sys/types.h>
#include <sys/socket.h>

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <debug.h>

#include <net/uip/uip.h>
#include <net/uip/dhcpc.h>
#include <net/uip/uip-lib.h>

/****************************************************************************
 * Definitions
 ****************************************************************************/

#define STATE_INITIAL           0
#define STATE_HAVE_OFFER        1
#define STATE_HAVE_LEASE        2

#define BOOTP_BROADCAST         0x8000

#define DHCP_REQUEST            1
#define DHCP_REPLY              2
#define DHCP_HTYPE_ETHERNET     1
#define DHCP_HLEN_ETHERNET      6
#define DHCP_MSG_LEN            236

#define DHCPC_SERVER_PORT       67
#define DHCPC_CLIENT_PORT       68

#define DHCPDISCOVER            1
#define DHCPOFFER               2
#define DHCPREQUEST             3
#define DHCPDECLINE             4
#define DHCPACK                 5
#define DHCPNAK                 6
#define DHCPRELEASE             7

#define DHCP_OPTION_SUBNET_MASK 1
#define DHCP_OPTION_ROUTER      3
#define DHCP_OPTION_DNS_SERVER  6
#define DHCP_OPTION_REQ_IPADDR  50
#define DHCP_OPTION_LEASE_TIME  51
#define DHCP_OPTION_MSG_TYPE    53
#define DHCP_OPTION_SERVER_ID   54
#define DHCP_OPTION_REQ_LIST    55
#define DHCP_OPTION_END         255

#define BUFFER_SIZE             256

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct dhcp_msg
{
  uint8  op;
  uint8  htype;
  uint8  hlen;
  uint8  hops;
  uint8  xid[4];
  uint16 secs;
  uint16 flags;
  uint8  ciaddr[4];
  uint8  yiaddr[4];
  uint8  siaddr[4];
  uint8  giaddr[4];
  uint8  chaddr[16];
#ifndef CONFIG_NET_DHCP_LIGHT
  uint8  sname[64];
  uint8  file[128];
#endif
  uint8  options[312];
};

struct dhcpc_state_s
{
  struct uip_udp_conn *ds_conn;
  const void          *ds_macaddr;
  int                  ds_maclen;
  int                  sockfd;
  struct in_addr       ipaddr;
  struct in_addr       serverid;
  struct dhcp_msg      packet;
};

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const uint8 xid[4]          = {0xad, 0xde, 0x12, 0x23};
static const uint8 magic_cookie[4] = {99, 130, 83, 99};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: dhcpc_add<option>
 ****************************************************************************/

static uint8 *dhcpc_addmsgtype(uint8 *optptr, uint8 type)
{
  *optptr++ = DHCP_OPTION_MSG_TYPE;
  *optptr++ = 1;
  *optptr++ = type;
  return optptr;
}

static uint8 *dhcpc_addserverid(struct in_addr *serverid, uint8 *optptr)
{
  *optptr++ = DHCP_OPTION_SERVER_ID;
  *optptr++ = 4;
  memcpy(optptr, &serverid->s_addr, 4);
  return optptr + 4;
}

static uint8 *dhcpc_addreqipaddr(struct in_addr *ipaddr, uint8 *optptr)
{
  *optptr++ = DHCP_OPTION_REQ_IPADDR;
  *optptr++ = 4;
  memcpy(optptr, &ipaddr->s_addr, 4);
  return optptr + 4;
}

static uint8 *dhcpc_addreqoptions(uint8 *optptr)
{
  *optptr++ = DHCP_OPTION_REQ_LIST;
  *optptr++ = 3;
  *optptr++ = DHCP_OPTION_SUBNET_MASK;
  *optptr++ = DHCP_OPTION_ROUTER;
  *optptr++ = DHCP_OPTION_DNS_SERVER;
  return optptr;
}

static uint8 *dhcpc_addend(uint8 *optptr)
{
  *optptr++ = DHCP_OPTION_END;
  return optptr;
}

/****************************************************************************
 * Name: dhcpc_sendmsg
 ****************************************************************************/

static int dhcpc_sendmsg(struct dhcpc_state_s *pdhcpc,
                         struct dhcpc_state *presult, int msgtype)
{
  struct sockaddr_in addr;
  uint8 *pend;
  in_addr_t serverid = INADDR_BROADCAST;
  int len;

  /* Create the common message header settings */

  memset(&pdhcpc->packet, 0, sizeof(struct dhcp_msg));
  pdhcpc->packet.op    = DHCP_REQUEST;
  pdhcpc->packet.htype = DHCP_HTYPE_ETHERNET;
  pdhcpc->packet.hlen  = pdhcpc->ds_maclen;
  memcpy(pdhcpc->packet.xid, xid, 4);
  memcpy(pdhcpc->packet.chaddr, pdhcpc->ds_macaddr, pdhcpc->ds_maclen);
  memset(&pdhcpc->packet.chaddr[pdhcpc->ds_maclen], 0, 16 - pdhcpc->ds_maclen);
  memcpy(pdhcpc->packet.options, magic_cookie, sizeof(magic_cookie));

  /* Add the common header options */

  pend = &pdhcpc->packet.options[4];
  pend = dhcpc_addmsgtype(pend, msgtype);

  /* Handle the message specific settings */

  switch (msgtype)
    {
      /* Broadcast DISCOVER message to all servers */

      case DHCPDISCOVER:
        pdhcpc->packet.flags = HTONS(BOOTP_BROADCAST); /*  Broadcast bit. */
        pend     = dhcpc_addreqoptions(pend);
        break;

      /* Send REQUEST message to the server that sent the *first* OFFER */

      case DHCPREQUEST:
        pdhcpc->packet.flags = HTONS(BOOTP_BROADCAST); /*  Broadcast bit. */
        memcpy(pdhcpc->packet.ciaddr, &pdhcpc->ipaddr.s_addr, 4);
        pend     = dhcpc_addserverid(&pdhcpc->serverid, pend);
        pend     = dhcpc_addreqipaddr(&pdhcpc->ipaddr, pend);
        break;

      /* Send DECLINE message to the server that sent the *last* OFFER */

      case DHCPDECLINE:
        memcpy(pdhcpc->packet.ciaddr, &presult->ipaddr.s_addr, 4);
        pend     = dhcpc_addserverid(&presult->serverid, pend);
        serverid = presult->serverid.s_addr;
        break;

      default:
        return ERROR;
    }

  pend = dhcpc_addend(pend);
  len  = pend - (uint8*)&pdhcpc->packet;

  /* Send the request */

  addr.sin_family      = AF_INET;
  addr.sin_port        = HTONS(DHCPC_SERVER_PORT);
  addr.sin_addr.s_addr = serverid;

  return sendto(pdhcpc->sockfd, &pdhcpc->packet, len, 0,
                (struct sockaddr*)&addr, sizeof(struct sockaddr_in));
}

/****************************************************************************
 * Name: dhcpc_parseoptions
 ****************************************************************************/

static uint8 dhcpc_parseoptions(struct dhcpc_state *presult, uint8 *optptr, int len)
{
  uint8 *end = optptr + len;
  uint8 type = 0;

  while (optptr < end)
    {
      switch(*optptr)
        {
          case DHCP_OPTION_SUBNET_MASK:
            memcpy(&presult->netmask.s_addr, optptr + 2, 4);
            break;
          case DHCP_OPTION_ROUTER:
            memcpy(&presult->default_router.s_addr, optptr + 2, 4);
            break;
          case DHCP_OPTION_DNS_SERVER:
            memcpy(&presult->dnsaddr.s_addr, optptr + 2, 4);
            break;
          case DHCP_OPTION_MSG_TYPE:
            type = *(optptr + 2);
            break;
          case DHCP_OPTION_SERVER_ID:
            memcpy(&presult->serverid.s_addr, optptr + 2, 4);
            break;
          case DHCP_OPTION_LEASE_TIME:
            memcpy(presult->lease_time, optptr + 2, 4);
            break;
          case DHCP_OPTION_END:
            return type;