text: /*
   * Copyright (c) 2007-2009 Fr�d�ric Bernon, Simon Goldschmidt
   * 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. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 lwIP TCP/IP stack.
   *
   * Author: Fr�d�ric Bernon, Simon Goldschmidt
   *
   */
  #ifndef LWIP_HDR_APPS_SNTP_OPTS_H
  #define LWIP_HDR_APPS_SNTP_OPTS_H
  
  #include "lwip/opt.h"
  
  /** SNTP macro to change system time in seconds
   * Define SNTP_SET_SYSTEM_TIME_US(sec, us) to set the time in microseconds instead of this one
   * if you need the additional precision.
   */
  #ifndef SNTP_SET_SYSTEM_TIME
  #define SNTP_SET_SYSTEM_TIME(sec)   LWIP_UNUSED_ARG(sec)
  #endif
  
  /** The maximum number of SNTP servers that can be set */
  #ifndef SNTP_MAX_SERVERS
  #define SNTP_MAX_SERVERS           LWIP_DHCP_MAX_NTP_SERVERS
  #endif
  
  /** Set this to 1 to implement the callback function called by dhcp when
   * NTP servers are received. */
  #ifndef SNTP_GET_SERVERS_FROM_DHCP
  #define SNTP_GET_SERVERS_FROM_DHCP LWIP_DHCP_GET_NTP_SRV
  #endif
  
  /* Set this to 1 to support DNS names (or IP address strings) to set sntp servers */
  #ifndef SNTP_SERVER_DNS
  #define SNTP_SERVER_DNS            0
  #endif
  
  /** One server address/name can be defined as default if SNTP_SERVER_DNS == 1:
   * #define SNTP_SERVER_ADDRESS "pool.ntp.org"
   */
  
  /**
   * SNTP_DEBUG: Enable debugging for SNTP.
   */
  #ifndef SNTP_DEBUG
  #define SNTP_DEBUG                  LWIP_DBG_OFF
  #endif
  
  /** SNTP server port */
  #ifndef SNTP_PORT
  #define SNTP_PORT                   123
  #endif
  
  /** Set this to 1 to allow config of SNTP server(s) by DNS name */
  #ifndef SNTP_SERVER_DNS
  #define SNTP_SERVER_DNS             0
  #endif
  
  /** Sanity check:
   * Define this to
   * - 0 to turn off sanity checks (default; smaller code)
   * - >= 1 to check address and port of the response packet to ensure the
   *        response comes from the server we sent the request to.
   * - >= 2 to check returned Originate Timestamp against Transmit Timestamp
   *        sent to the server (to ensure response to older request).
   * - >= 3 @todo: discard reply if any of the LI, Stratum, or Transmit Timestamp
   *        fields is 0 or the Mode field is not 4 (unicast) or 5 (broadcast).
   * - >= 4 @todo: to check that the Root Delay and Root Dispersion fields are each
   *        greater than or equal to 0 and less than infinity, where infinity is
   *        currently a cozy number like one second. This check avoids using a
   *        server whose synchronization source has expired for a very long time.
   */
  #ifndef SNTP_CHECK_RESPONSE
  #define SNTP_CHECK_RESPONSE         0
  #endif
  
  /** According to the RFC, this shall be a random delay
   * between 1 and 5 minutes (in milliseconds) to prevent load peaks.
   * This can be defined to a random generation function,
   * which must return the delay in milliseconds as u32_t.
   * Turned off by default.
   */
  #ifndef SNTP_STARTUP_DELAY
  #define SNTP_STARTUP_DELAY          0
  #endif
  
  /** If you want the startup delay to be a function, define this
   * to a function (including the brackets) and define SNTP_STARTUP_DELAY to 1.
   */
  #ifndef SNTP_STARTUP_DELAY_FUNC
  #define SNTP_STARTUP_DELAY_FUNC     SNTP_STARTUP_DELAY
  #endif
  
  /** SNTP receive timeout - in milliseconds
   * Also used as retry timeout - this shouldn't be too low.
   * Default is 3 seconds.
   */
  #ifndef SNTP_RECV_TIMEOUT
  #define SNTP_RECV_TIMEOUT           3000
  #endif
  
  /** SNTP update delay - in milliseconds
   * Default is 1 hour. Must not be beolw 15 seconds by specification (i.e. 15000)
   */
  #ifndef SNTP_UPDATE_DELAY
  #define SNTP_UPDATE_DELAY           3600000
  #endif
  
  /** SNTP macro to get system time, used with SNTP_CHECK_RESPONSE >= 2
   * to send in request and compare in response.
   */
  #ifndef SNTP_GET_SYSTEM_TIME
  #define SNTP_GET_SYSTEM_TIME(sec, us)     do { (sec) = 0; (us) = 0; } while(0)
  #endif
  
  /** Default retry timeout (in milliseconds) if the response
   * received is invalid.
   * This is doubled with each retry until SNTP_RETRY_TIMEOUT_MAX is reached.
   */
  #ifndef SNTP_RETRY_TIMEOUT
  #define SNTP_RETRY_TIMEOUT          SNTP_RECV_TIMEOUT
  #endif
  
  /** Maximum retry timeout (in milliseconds). */
  #ifndef SNTP_RETRY_TIMEOUT_MAX
  #define SNTP_RETRY_TIMEOUT_MAX      (SNTP_RETRY_TIMEOUT * 10)
  #endif
  
  /** Increase retry timeout with every retry sent
   * Default is on to conform to RFC.
   */
  #ifndef SNTP_RETRY_TIMEOUT_EXP
  #define SNTP_RETRY_TIMEOUT_EXP      1
  #endif
  
  #endif /* LWIP_HDR_APPS_SNTP_OPTS_H */
  