dhcp.c

lwip-1.4.0

      }
    }
    /* proceed to next netif */
    netif = netif->next;
  }
}

/**
 * DHCP transaction timeout handling
 *
 * A DHCP server is expected to respond within a short period of time.
 * This timer checks whether an outstanding DHCP request is timed out.
 */
void
dhcp_fine_tmr()
{
  struct netif *netif = netif_list;
  /* loop through netif's */
  while (netif != NULL) {
    /* only act on DHCP configured interfaces */
    if (netif->dhcp != NULL) {
      /* timer is active (non zero), and is about to trigger now */      
      if (netif->dhcp->request_timeout > 1) {
        netif->dhcp->request_timeout--;
      }
      else if (netif->dhcp->request_timeout == 1) {
        netif->dhcp->request_timeout--;
        /* { netif->dhcp->request_timeout == 0 } */
        LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_fine_tmr(): request timeout\n"));
        /* this client's request timeout triggered */
        dhcp_timeout(netif);
      }
    }
    /* proceed to next network interface */
    netif = netif->next;
  }
}

/**
 * A DHCP negotiation transaction, or ARP request, has timed out.
 *
 * The timer that was started with the DHCP or ARP request has
 * timed out, indicating no response was received in time.
 *
 * @param netif the netif under DHCP control
 */
static void
dhcp_timeout(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout()\n"));
  /* back-off period has passed, or server selection timed out */
  if ((dhcp->state == DHCP_BACKING_OFF) || (dhcp->state == DHCP_SELECTING)) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout(): restarting discovery\n"));
    dhcp_discover(netif);
  /* receiving the requested lease timed out */
  } else if (dhcp->state == DHCP_REQUESTING) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, DHCP request timed out\n"));
    if (dhcp->tries <= 5) {
      dhcp_select(netif);
    } else {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting\n"));
      dhcp_release(netif);
      dhcp_discover(netif);
    }
#if DHCP_DOES_ARP_CHECK
  /* received no ARP reply for the offered address (which is good) */
  } else if (dhcp->state == DHCP_CHECKING) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): CHECKING, ARP request timed out\n"));
    if (dhcp->tries <= 1) {
      dhcp_check(netif);
    /* no ARP replies on the offered address,
       looks like the IP address is indeed free */
    } else {
      /* bind the interface to the offered address */
      dhcp_bind(netif);
    }
#endif /* DHCP_DOES_ARP_CHECK */
  }
  /* did not get response to renew request? */
  else if (dhcp->state == DHCP_RENEWING) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RENEWING, DHCP request timed out\n"));
    /* just retry renewal */
    /* note that the rebind timer will eventually time-out if renew does not work */
    dhcp_renew(netif);
  /* did not get response to rebind request? */
  } else if (dhcp->state == DHCP_REBINDING) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REBINDING, DHCP request timed out\n"));
    if (dhcp->tries <= 8) {
      dhcp_rebind(netif);
    } else {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING\n"));
      dhcp_release(netif);
      dhcp_discover(netif);
    }
  } else if (dhcp->state == DHCP_REBOOTING) {
    if (dhcp->tries < REBOOT_TRIES) {
      dhcp_reboot(netif);
    } else {
      dhcp_discover(netif);
    }
  }
}

/**
 * The renewal period has timed out.
 *
 * @param netif the netif under DHCP control
 */
static void
dhcp_t1_timeout(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_t1_timeout()\n"));
  if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
      (dhcp->state == DHCP_RENEWING)) {
    /* just retry to renew - note that the rebind timer (t2) will
     * eventually time-out if renew tries fail. */
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
                ("dhcp_t1_timeout(): must renew\n"));
    /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
       DHCP_RENEWING, not DHCP_BOUND */
    dhcp_renew(netif);
  }
}

/**
 * The rebind period has timed out.
 *
 * @param netif the netif under DHCP control
 */
static void
dhcp_t2_timeout(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout()\n"));
  if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) ||
      (dhcp->state == DHCP_RENEWING)) {
    /* just retry to rebind */
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
                ("dhcp_t2_timeout(): must rebind\n"));
    /* This slightly different to RFC2131: DHCPREQUEST will be sent from state
       DHCP_REBINDING, not DHCP_BOUND */
    dhcp_rebind(netif);
  }
}

/**
 * Handle a DHCP ACK packet
 *
 * @param netif the netif under DHCP control
 */
static void
dhcp_handle_ack(struct netif *netif)
{
  struct dhcp *dhcp = netif->dhcp;
#if LWIP_DNS
  u8_t n;
#endif /* LWIP_DNS */

  /* clear options we might not get from the ACK */
  ip_addr_set_zero(&dhcp->offered_sn_mask);
  ip_addr_set_zero(&dhcp->offered_gw_addr);
#if LWIP_DHCP_BOOTP_FILE
  ip_addr_set_zero(&dhcp->offered_si_addr);
#endif /* LWIP_DHCP_BOOTP_FILE */

  /* lease time given? */
  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_LEASE_TIME)) {
    /* remember offered lease time */
    dhcp->offered_t0_lease = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_LEASE_TIME);
  }
  /* renewal period given? */
  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T1)) {
    /* remember given renewal period */
    dhcp->offered_t1_renew = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T1);
  } else {
    /* calculate safe periods for renewal */
    dhcp->offered_t1_renew = dhcp->offered_t0_lease / 2;
  }

  /* renewal period given? */
  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_T2)) {
    /* remember given rebind period */
    dhcp->offered_t2_rebind = dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_T2);
  } else {
    /* calculate safe periods for rebinding */
    dhcp->offered_t2_rebind = dhcp->offered_t0_lease;
  }

  /* (y)our internet address */
  ip_addr_copy(dhcp->offered_ip_addr, dhcp->msg_in->yiaddr);

#if LWIP_DHCP_BOOTP_FILE
  /* copy boot server address,
     boot file name copied in dhcp_parse_reply if not overloaded */
  ip_addr_copy(dhcp->offered_si_addr, dhcp->msg_in->siaddr);
#endif /* LWIP_DHCP_BOOTP_FILE */

  /* subnet mask given? */
  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)) {
    /* remember given subnet mask */
    ip4_addr_set_u32(&dhcp->offered_sn_mask, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_SUBNET_MASK)));
    dhcp->subnet_mask_given = 1;
  } else {
    dhcp->subnet_mask_given = 0;
  }

  /* gateway router */
  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_ROUTER)) {
    ip4_addr_set_u32(&dhcp->offered_gw_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_ROUTER)));
  }
  
#if LWIP_DNS
  /* DNS servers */
  n = 0;
  while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) {
    ip_addr_t dns_addr;
    ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n)));
    dns_setserver(n, &dns_addr);
    n++;
  }
#endif /* LWIP_DNS */
}

/** Set a statically allocated struct dhcp to work with.
 * Using this prevents dhcp_start to allocate it using mem_malloc.
 *
 * @param netif the netif for which to set the struct dhcp
 * @param dhcp (uninitialised) dhcp struct allocated by the application
 */
void
dhcp_set_struct(struct netif *netif, struct dhcp *dhcp)
{
  LWIP_ASSERT("netif != NULL", netif != NULL);
  LWIP_ASSERT("dhcp != NULL", dhcp != NULL);
  LWIP_ASSERT("netif already has a struct dhcp set", netif->dhcp == NULL);

  /* clear data structure */
  memset(dhcp, 0, sizeof(struct dhcp));
  /* dhcp_set_state(&dhcp, DHCP_OFF); */
  netif->dhcp = dhcp;
}

/** Removes a struct dhcp from a netif.
 *
 * ATTENTION: Only use this when not using dhcp_set_struct() to allocate the
 *            struct dhcp since the memory is passed back to the heap.
 *
 * @param netif the netif from which to remove the struct dhcp
 */
void dhcp_cleanup(struct netif *netif)
{
  LWIP_ASSERT("netif != NULL", netif != NULL);

  if (netif->dhcp != NULL) {
    mem_free(netif->dhcp);
    netif->dhcp = NULL;
  }
}

/**
 * Start DHCP negotiation for a network interface.
 *
 * If no DHCP client instance was attached to this interface,
 * a new client is created first. If a DHCP client instance
 * was already present, it restarts negotiation.
 *
 * @param netif The lwIP network interface
 * @return lwIP error code
 * - ERR_OK - No error
 * - ERR_MEM - Out of memory
 */
err_t
dhcp_start(struct netif *netif)
{
  struct dhcp *dhcp;
  err_t result = ERR_OK;

  LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);
  dhcp = netif->dhcp;
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
  /* Remove the flag that says this netif is handled by DHCP,
     it is set when we succeeded starting. */
  netif->flags &= ~NETIF_FLAG_DHCP;

  /* check hwtype of the netif */
  if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): No ETHARP netif\n"));
    return ERR_ARG;
  }

  /* check MTU of the netif */
  if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n"));
    return ERR_MEM;
  }

  /* no DHCP client attached yet? */
  if (dhcp == NULL) {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n"));
    dhcp = (struct dhcp *)mem_malloc(sizeof(struct dhcp));
    if (dhcp == NULL) {
      LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
      return ERR_MEM;
    }
    /* store this dhcp client in the netif */
    netif->dhcp = dhcp;
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
  /* already has DHCP client attached */
  } else {
    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(): restarting DHCP configuration\n"));
    if (dhcp->pcb != NULL) {
      udp_remove(dhcp->pcb);
    }
    LWIP_ASSERT("pbuf p_out wasn't freed", dhcp->p_out == NULL);
    LWIP_ASSERT("reply wasn't freed", dhcp->msg_in == NULL );
  }
    
  /* clear data structure */
  memset(dhcp, 0, sizeof(struct dhcp));
  /* dhcp_set_state(&dhcp, DHCP_OFF); */
  /* allocate UDP PCB */
  dhcp->pcb = udp_new();
  if (dhcp->pcb == NULL) {
    LWIP_DEBUGF(DHCP_DEBUG  | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
    return ERR_MEM;
  }
  dhcp->pcb->so_options |= SOF_BROADCAST;
  /* set up local and remote port for the pcb */
  udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
  udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
  /* set up the recv callback and argument */
  udp_recv(dhcp->pcb, dhcp_recv, netif);
  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
  /* (re)start the DHCP negotiation */
  result = dhcp_discover(netif);
  if (result != ERR_OK) {
    /* free resources allocated above */
    dhcp_stop(netif);
    return ERR_MEM;
  }
  /* Set the flag that says this netif is handled by DHCP. */
  netif->flags |= NETIF_FLAG_DHCP;
  return result;
}

/**
 * Inform a DHCP server of our manual configuration.
 *