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/**
* @file
* SNTP client options list
*/
/*
* Copyright (c) 2007-2009 Frédéric 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: Frédéric Bernon, Simon Goldschmidt
*
*/
#ifndef LWIP_HDR_APPS_SNTP_OPTS_H
#define LWIP_HDR_APPS_SNTP_OPTS_H
#include "lwip/opt.h"
#include "lwip/prot/iana.h"
/**
* @defgroup sntp_opts Options
* @ingroup sntp
* @{
*/
/** 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. Alternatively,
* define SNTP_SET_SYSTEM_TIME_NTP(sec, frac) in order to work with native
* NTP timestamps instead.
*/
#if !defined SNTP_SET_SYSTEM_TIME || defined __DOXYGEN__
#define SNTP_SET_SYSTEM_TIME(sec) LWIP_UNUSED_ARG(sec)
#endif
/** The maximum number of SNTP servers that can be set */
#if !defined SNTP_MAX_SERVERS || defined __DOXYGEN__
#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. */
#if !defined SNTP_GET_SERVERS_FROM_DHCP || defined __DOXYGEN__
#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
* One server address/name can be defined as default if SNTP_SERVER_DNS == 1:
* \#define SNTP_SERVER_ADDRESS "pool.ntp.org"
*/
#if !defined SNTP_SERVER_DNS || defined __DOXYGEN__
#define SNTP_SERVER_DNS 0
#endif
/**
* SNTP_DEBUG: Enable debugging for SNTP.
*/
#if !defined SNTP_DEBUG || defined __DOXYGEN__
#define SNTP_DEBUG LWIP_DBG_OFF
#endif
/** SNTP server port */
#if !defined SNTP_PORT || defined __DOXYGEN__
#define SNTP_PORT LWIP_IANA_PORT_SNTP
#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 VN, 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.
*/
#if !defined SNTP_CHECK_RESPONSE || defined __DOXYGEN__
#define SNTP_CHECK_RESPONSE 0
#endif
/** Enable round-trip delay compensation.
* Compensate for the round-trip delay by calculating the clock offset from
* the originate, receive, transmit and destination timestamps, as per RFC.
*
* The calculation requires compiler support for 64-bit integers. Also, either
* SNTP_SET_SYSTEM_TIME_US or SNTP_SET_SYSTEM_TIME_NTP has to be implemented
* for setting the system clock with sub-second precision. Likewise, either
* SNTP_GET_SYSTEM_TIME or SNTP_GET_SYSTEM_TIME_NTP needs to be implemented
* with sub-second precision.
*
* Although not strictly required, it makes sense to combine this option with
* SNTP_CHECK_RESPONSE >= 2 for sanity-checking of the received timestamps.
* Also, in order for the round-trip calculation to work, the difference
* between the local clock and the NTP server clock must not be larger than
* about 34 years. If that limit is exceeded, the implementation will fall back
* to setting the clock without compensation. In order to ensure that the local
* clock is always within the permitted range for compensation, even at first
* try, it may be necessary to store at least the current year in non-volatile
* memory.
*/
#if !defined SNTP_COMP_ROUNDTRIP || defined __DOXYGEN__
#define SNTP_COMP_ROUNDTRIP 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.
*/
#if !defined SNTP_STARTUP_DELAY || defined __DOXYGEN__
#ifdef LWIP_RAND
#define SNTP_STARTUP_DELAY 1
#else
#define SNTP_STARTUP_DELAY 0
#endif
#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.
*/
#if !defined SNTP_STARTUP_DELAY_FUNC || defined __DOXYGEN__
#define SNTP_STARTUP_DELAY_FUNC (LWIP_RAND() % 5000)
#endif
/** SNTP receive timeout - in milliseconds
* Also used as retry timeout - this shouldn't be too low.
* Default is 15 seconds. Must not be beolw 15 seconds by specification (i.e. 15000)
*/
#if !defined SNTP_RECV_TIMEOUT || defined __DOXYGEN__
#define SNTP_RECV_TIMEOUT 15000
#endif
/** SNTP update delay - in milliseconds
* Default is 1 hour. Must not be beolw 60 seconds by specification (i.e. 60000)
*/
#if !defined SNTP_UPDATE_DELAY || defined __DOXYGEN__
#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. Also used for round-trip
* delay compensation if SNTP_COMP_ROUNDTRIP != 0.
* Alternatively, define SNTP_GET_SYSTEM_TIME_NTP(sec, frac) in order to
* work with native NTP timestamps instead.
*/
#if !defined SNTP_GET_SYSTEM_TIME || defined __DOXYGEN__
#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.
*/
#if !defined SNTP_RETRY_TIMEOUT || defined __DOXYGEN__
#define SNTP_RETRY_TIMEOUT SNTP_RECV_TIMEOUT
#endif
/** Maximum retry timeout (in milliseconds). */
#if !defined SNTP_RETRY_TIMEOUT_MAX || defined __DOXYGEN__
#define SNTP_RETRY_TIMEOUT_MAX (SNTP_RETRY_TIMEOUT * 10)
#endif
/** Increase retry timeout with every retry sent
* Default is on to conform to RFC.
*/
#if !defined SNTP_RETRY_TIMEOUT_EXP || defined __DOXYGEN__
#define SNTP_RETRY_TIMEOUT_EXP 1
#endif
/**
* @}
*/
#endif /* LWIP_HDR_APPS_SNTP_OPTS_H */