3 * SNTP client options list
7 * Copyright (c) 2007-2009 Frédéric Bernon, Simon Goldschmidt
10 * Redistribution and use in source and binary forms, with or without modification,
11 * are permitted provided that the following conditions are met:
13 * 1. Redistributions of source code must retain the above copyright notice,
14 * this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32 * This file is part of the lwIP TCP/IP stack.
34 * Author: Frédéric Bernon, Simon Goldschmidt
37 #ifndef LWIP_HDR_APPS_SNTP_OPTS_H
38 #define LWIP_HDR_APPS_SNTP_OPTS_H
43 * @defgroup sntp_opts Options
48 /** SNTP macro to change system time in seconds
49 * Define SNTP_SET_SYSTEM_TIME_US(sec, us) to set the time in microseconds instead of this one
50 * if you need the additional precision.
52 #if !defined SNTP_SET_SYSTEM_TIME || defined __DOXYGEN__
53 #define SNTP_SET_SYSTEM_TIME(sec) LWIP_UNUSED_ARG(sec)
56 /** The maximum number of SNTP servers that can be set */
57 #if !defined SNTP_MAX_SERVERS || defined __DOXYGEN__
58 #define SNTP_MAX_SERVERS LWIP_DHCP_MAX_NTP_SERVERS
61 /** Set this to 1 to implement the callback function called by dhcp when
62 * NTP servers are received. */
63 #if !defined SNTP_GET_SERVERS_FROM_DHCP || defined __DOXYGEN__
64 #define SNTP_GET_SERVERS_FROM_DHCP LWIP_DHCP_GET_NTP_SRV
67 /** Set this to 1 to support DNS names (or IP address strings) to set sntp servers
68 * One server address/name can be defined as default if SNTP_SERVER_DNS == 1:
69 * \#define SNTP_SERVER_ADDRESS "pool.ntp.org"
71 #if !defined SNTP_SERVER_DNS || defined __DOXYGEN__
72 #define SNTP_SERVER_DNS 0
76 * SNTP_DEBUG: Enable debugging for SNTP.
78 #if !defined SNTP_DEBUG || defined __DOXYGEN__
79 #define SNTP_DEBUG LWIP_DBG_OFF
82 /** SNTP server port */
83 #if !defined SNTP_PORT || defined __DOXYGEN__
87 /** Set this to 1 to allow config of SNTP server(s) by DNS name */
88 #if !defined SNTP_SERVER_DNS || defined __DOXYGEN__
89 #define SNTP_SERVER_DNS 0
94 * - 0 to turn off sanity checks (default; smaller code)
95 * - >= 1 to check address and port of the response packet to ensure the
96 * response comes from the server we sent the request to.
97 * - >= 2 to check returned Originate Timestamp against Transmit Timestamp
98 * sent to the server (to ensure response to older request).
99 * - >= 3 @todo: discard reply if any of the LI, Stratum, or Transmit Timestamp
100 * fields is 0 or the Mode field is not 4 (unicast) or 5 (broadcast).
101 * - >= 4 @todo: to check that the Root Delay and Root Dispersion fields are each
102 * greater than or equal to 0 and less than infinity, where infinity is
103 * currently a cozy number like one second. This check avoids using a
104 * server whose synchronization source has expired for a very long time.
106 #if !defined SNTP_CHECK_RESPONSE || defined __DOXYGEN__
107 #define SNTP_CHECK_RESPONSE 0
110 /** According to the RFC, this shall be a random delay
111 * between 1 and 5 minutes (in milliseconds) to prevent load peaks.
112 * This can be defined to a random generation function,
113 * which must return the delay in milliseconds as u32_t.
114 * Turned off by default.
116 #if !defined SNTP_STARTUP_DELAY || defined __DOXYGEN__
117 #define SNTP_STARTUP_DELAY 0
120 /** If you want the startup delay to be a function, define this
121 * to a function (including the brackets) and define SNTP_STARTUP_DELAY to 1.
123 #if !defined SNTP_STARTUP_DELAY_FUNC || defined __DOXYGEN__
124 #define SNTP_STARTUP_DELAY_FUNC SNTP_STARTUP_DELAY
127 /** SNTP receive timeout - in milliseconds
128 * Also used as retry timeout - this shouldn't be too low.
129 * Default is 3 seconds.
131 #if !defined SNTP_RECV_TIMEOUT || defined __DOXYGEN__
132 #define SNTP_RECV_TIMEOUT 3000
135 /** SNTP update delay - in milliseconds
136 * Default is 1 hour. Must not be beolw 15 seconds by specification (i.e. 15000)
138 #if !defined SNTP_UPDATE_DELAY || defined __DOXYGEN__
139 #define SNTP_UPDATE_DELAY 3600000
142 /** SNTP macro to get system time, used with SNTP_CHECK_RESPONSE >= 2
143 * to send in request and compare in response.
145 #if !defined SNTP_GET_SYSTEM_TIME || defined __DOXYGEN__
146 #define SNTP_GET_SYSTEM_TIME(sec, us) do { (sec) = 0; (us) = 0; } while(0)
149 /** Default retry timeout (in milliseconds) if the response
150 * received is invalid.
151 * This is doubled with each retry until SNTP_RETRY_TIMEOUT_MAX is reached.
153 #if !defined SNTP_RETRY_TIMEOUT || defined __DOXYGEN__
154 #define SNTP_RETRY_TIMEOUT SNTP_RECV_TIMEOUT
157 /** Maximum retry timeout (in milliseconds). */
158 #if !defined SNTP_RETRY_TIMEOUT_MAX || defined __DOXYGEN__
159 #define SNTP_RETRY_TIMEOUT_MAX (SNTP_RETRY_TIMEOUT * 10)
162 /** Increase retry timeout with every retry sent
163 * Default is on to conform to RFC.
165 #if !defined SNTP_RETRY_TIMEOUT_EXP || defined __DOXYGEN__
166 #define SNTP_RETRY_TIMEOUT_EXP 1
173 #endif /* LWIP_HDR_APPS_SNTP_OPTS_H */