dhcp.c

来自「lwip-1.4.0」· C语言 代码 · 共 1,746 行 · 第 1/5 页

 * This informs DHCP servers of our fixed IP address configuration
 * by sending an INFORM message. It does not involve DHCP address
 * configuration, it is just here to be nice to the network.
 *
 * @param netif The lwIP network interface
 */
void
dhcp_inform(struct netif *netif)
{
  struct dhcp dhcp;
  err_t result = ERR_OK;
  struct udp_pcb *pcb;

  LWIP_ERROR("netif != NULL", (netif != NULL), return;);

  memset(&dhcp, 0, sizeof(struct dhcp));
  dhcp_set_state(&dhcp, DHCP_INFORM);

  if ((netif->dhcp != NULL) && (netif->dhcp->pcb != NULL)) {
    /* re-use existing pcb */
    pcb = netif->dhcp->pcb;
  } else {
    pcb = udp_new();
    if (pcb == NULL) {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform(): could not obtain pcb"));
      return;
    }
    dhcp.pcb = pcb;
    dhcp.pcb->so_options |= SOF_BROADCAST;
    udp_bind(dhcp.pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
  }
  /* create and initialize the DHCP message header */
  result = dhcp_create_msg(netif, &dhcp, DHCP_INFORM);
  if (result == ERR_OK) {
    dhcp_option(&dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
    dhcp_option_short(&dhcp, DHCP_MAX_MSG_LEN(netif));

    dhcp_option_trailer(&dhcp);

    pbuf_realloc(dhcp.p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp.options_out_len);

    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
    udp_sendto_if(pcb, dhcp.p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
    dhcp_delete_msg(&dhcp);
  } else {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_inform: could not allocate DHCP request\n"));
  }

  if (dhcp.pcb != NULL) {
    /* otherwise, the existing pcb was used */
    udp_remove(dhcp.pcb);
  }
}

/** Handle a possible change in the network configuration.
 *
 * This enters the REBOOTING state to verify that the currently bound
 * address is still valid.
 */
void
dhcp_network_changed(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  if (!dhcp)
    return;
  switch (dhcp->state) {
  case DHCP_REBINDING:
  case DHCP_RENEWING:
  case DHCP_BOUND:
  case DHCP_REBOOTING:
    netif_set_down(netif);
    dhcp->tries = 0;
    dhcp_reboot(netif);
    break;
  case DHCP_OFF:
    /* stay off */
    break;
  default:
    dhcp->tries = 0;
#if LWIP_DHCP_AUTOIP_COOP
    if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
      autoip_stop(netif);
      dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
    }
#endif /* LWIP_DHCP_AUTOIP_COOP */
    dhcp_discover(netif);
    break;
  }
}

#if DHCP_DOES_ARP_CHECK
/**
 * Match an ARP reply with the offered IP address.
 *
 * @param netif the network interface on which the reply was received
 * @param addr The IP address we received a reply from
 */
void dhcp_arp_reply(struct netif *netif, ip_addr_t *addr)
{
  LWIP_ERROR("netif != NULL", (netif != NULL), return;);
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_arp_reply()\n"));
  /* is a DHCP client doing an ARP check? */
  if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n",
      ip4_addr_get_u32(addr)));
    /* did a host respond with the address we
       were offered by the DHCP server? */
    if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) {
      /* we will not accept the offered address */
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
        ("dhcp_arp_reply(): arp reply matched with offered address, declining\n"));
      dhcp_decline(netif);
    }
  }
}

/**
 * Decline an offered lease.
 *
 * Tell the DHCP server we do not accept the offered address.
 * One reason to decline the lease is when we find out the address
 * is already in use by another host (through ARP).
 *
 * @param netif the netif under DHCP control
 */
static err_t
dhcp_decline(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  err_t result = ERR_OK;
  u16_t msecs;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline()\n"));
  dhcp_set_state(dhcp, DHCP_BACKING_OFF);
  /* create and initialize the DHCP message header */
  result = dhcp_create_msg(netif, dhcp, DHCP_DECLINE);
  if (result == ERR_OK) {
    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
    dhcp_option_long(dhcp, ntohl(ip4_addr_get_u32(&dhcp->offered_ip_addr)));

    dhcp_option_trailer(dhcp);
    /* resize pbuf to reflect true size of options */
    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);

    /* per section 4.4.4, broadcast DECLINE messages */
    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
    dhcp_delete_msg(dhcp);
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
  } else {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
      ("dhcp_decline: could not allocate DHCP request\n"));
  }
  dhcp->tries++;
  msecs = 10*1000;
  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs));
  return result;
}
#endif /* DHCP_DOES_ARP_CHECK */


/**
 * Start the DHCP process, discover a DHCP server.
 *
 * @param netif the netif under DHCP control
 */
static err_t
dhcp_discover(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  err_t result = ERR_OK;
  u16_t msecs;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover()\n"));
  ip_addr_set_any(&dhcp->offered_ip_addr);
  dhcp_set_state(dhcp, DHCP_SELECTING);
  /* create and initialize the DHCP message header */
  result = dhcp_create_msg(netif, dhcp, DHCP_DISCOVER);
  if (result == ERR_OK) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));

    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));

    dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
    dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
    dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
    dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
    dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);

    dhcp_option_trailer(dhcp);

    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n"));
    pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);

    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
    udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
    dhcp_delete_msg(dhcp);
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
  } else {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp_discover: could not allocate DHCP request\n"));
  }
  dhcp->tries++;
#if LWIP_DHCP_AUTOIP_COOP
  if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) {
    dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON;
    autoip_start(netif);
  }
#endif /* LWIP_DHCP_AUTOIP_COOP */
  msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
  dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
  return result;
}


/**
 * Bind the interface to the offered IP address.
 *
 * @param netif network interface to bind to the offered address
 */
static void
dhcp_bind(struct netif *netif)
{
  u32_t timeout;
  struct dhcp *dhcp;
  ip_addr_t sn_mask, gw_addr;
  LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;);
  dhcp = netif->dhcp;
  LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;);
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));

  /* temporary DHCP lease? */
  if (dhcp->offered_t1_renew != 0xffffffffUL) {
    /* set renewal period timer */
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew));
    timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
    if(timeout > 0xffff) {
      timeout = 0xffff;
    }
    dhcp->t1_timeout = (u16_t)timeout;
    if (dhcp->t1_timeout == 0) {
      dhcp->t1_timeout = 1;
    }
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000));
  }
  /* set renewal period timer */
  if (dhcp->offered_t2_rebind != 0xffffffffUL) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind));
    timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
    if(timeout > 0xffff) {
      timeout = 0xffff;
    }
    dhcp->t2_timeout = (u16_t)timeout;
    if (dhcp->t2_timeout == 0) {
      dhcp->t2_timeout = 1;
    }
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
  }

  if (dhcp->subnet_mask_given) {
    /* copy offered network mask */
    ip_addr_copy(sn_mask, dhcp->offered_sn_mask);
  } else {
    /* subnet mask not given, choose a safe subnet mask given the network class */
    u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
    if (first_octet <= 127) {
      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000UL));
    } else if (first_octet >= 192) {
      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00UL));
    } else {
      ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000UL));
    }
  }

  ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
  /* gateway address not given? */
  if (ip_addr_isany(&gw_addr)) {
    /* copy network address */
    ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask);
    /* use first host address on network as gateway */
    ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | PP_HTONL(0x00000001UL));
  }

#if LWIP_DHCP_AUTOIP_COOP
  if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
    autoip_stop(netif);
    dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
  }
#endif /* LWIP_DHCP_AUTOIP_COOP */

  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: 0x%08"X32_F"\n",
    ip4_addr_get_u32(&dhcp->offered_ip_addr)));
  netif_set_ipaddr(netif, &dhcp->offered_ip_addr);
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n",
    ip4_addr_get_u32(&sn_mask)));
  netif_set_netmask(netif, &sn_mask);
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n",
    ip4_addr_get_u32(&gw_addr)));
  netif_set_gw(netif, &gw_addr);
  /* bring the interface up */
  netif_set_up(netif);
  /* netif is now bound to DHCP leased address */
  dhcp_set_state(dhcp, DHCP_BOUND);
}

/**
 * Renew an existing DHCP lease at the involved DHCP server.
 *
 * @param netif network interface which must renew its lease
 */
err_t
dhcp_renew(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  err_t result;
  u16_t msecs;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_renew()\n"));
  dhcp_set_state(dhcp, DHCP_RENEWING);

  /* create and initialize the DHCP message header */
  result = dhcp_create_msg(netif, dhcp, DHCP_REQUEST);
  if (result == ERR_OK) {
    dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
    dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));

#if LWIP_NETIF_HOSTNAME
    if (netif->hostname != NULL) {
      const char *p = (const char*)netif->hostname;
      u8_t namelen = (u8_t)strlen(p);
      if (namelen > 0) {
        LWIP_ASSERT("DHCP: hostname is too long!", namelen < 255);
        dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, namelen);
        while (*p) {
          dhcp_option_byte(dhcp, *p++);
        }
      }
    }
#endif /* LWIP_NETIF_HOSTNAME */

#if 0
    dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
    dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
#endif

#if 0
    dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
    dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
#endif
    /* append DHCP message trailer */