sntp_client.h

00001 /**
00002  * @file sntp_client.h
00003  * @brief SNTP client (Simple Network Time Protocol)
00004  *
00005  * @section License
00006  *
00007  * Copyright (C) 2010-2017 Oryx Embedded SARL. All rights reserved.
00008  *
00009  * This file is part of CycloneTCP Open.
00010  *
00011  * This program is free software; you can redistribute it and/or
00012  * modify it under the terms of the GNU General Public License
00013  * as published by the Free Software Foundation; either version 2
00014  * of the License, or (at your option) any later version.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU General Public License
00022  * along with this program; if not, write to the Free Software Foundation,
00023  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
00024  *
00025  * @author Oryx Embedded SARL (www.oryx-embedded.com)
00026  * @version 1.7.6
00027  **/
00028 
00029 //Dependencies
00030 #include "core/net.h"
00031 #include "core/socket.h"
00032 
00033 //SNTP client support
00034 #ifndef SNTP_CLIENT_SUPPORT
00035    #define SNTP_CLIENT_SUPPORT ENABLED
00036 #elif (SNTP_CLIENT_SUPPORT != ENABLED && SNTP_CLIENT_SUPPORT != DISABLED)
00037    #error SNTP_CLIENT_SUPPORT parameter is not valid
00038 #endif
00039 
00040 //Maximum number of retransmissions of SNTP requests
00041 #ifndef SNTP_CLIENT_MAX_RETRIES
00042    #define SNTP_CLIENT_MAX_RETRIES 3
00043 #elif (SNTP_CLIENT_MAX_RETRIES < 1)
00044    #error SNTP_CLIENT_MAX_RETRIES parameter is not valid
00045 #endif
00046 
00047 //Initial retransmission timeout
00048 #ifndef SNTP_CLIENT_INIT_TIMEOUT
00049    #define SNTP_CLIENT_INIT_TIMEOUT 1000
00050 #elif (SNTP_CLIENT_INIT_TIMEOUT < 1000)
00051    #error SNTP_CLIENT_INIT_TIMEOUT parameter is not valid
00052 #endif
00053 
00054 //Maximum retransmission timeout
00055 #ifndef SNTP_CLIENT_MAX_TIMEOUT
00056    #define SNTP_CLIENT_MAX_TIMEOUT 5000
00057 #elif (SNTP_CLIENT_MAX_TIMEOUT < 1000)
00058    #error SNTP_CLIENT_MAX_TIMEOUT parameter is not valid
00059 #endif
00060 
00061 //NTP port number
00062 #define NTP_PORT 123
00063 //Maximum size of NTP packets
00064 #define NTP_MESSAGE_MAX_SIZE 68
00065 
00066 /**
00067  * @brief Leap indicator
00068  **/
00069 
00070 typedef enum
00071 {
00072    NTP_LI_NO_WARNING           = 0,
00073    NTP_LI_LAST_MIN_HAS_61_SECS = 1,
00074    NTP_LI_LAST_MIN_HAS_59_SECS = 2,
00075    NTP_LI_ALARM_CONDITION      = 3
00076 } NtpLeapIndicator;
00077 
00078 
00079 /**
00080  * @brief NTP version number
00081  **/
00082 
00083 typedef enum
00084 {
00085    NTP_VERSION_1 = 1,
00086    NTP_VERSION_2 = 2,
00087    NTP_VERSION_3 = 3,
00088    NTP_VERSION_4 = 4
00089 } NtpVersion;
00090 
00091 
00092 /**
00093  * @brief Protocol mode
00094  **/
00095 
00096 typedef enum
00097 {
00098    NTP_MODE_SYMMETRIC_ACTIVE  = 1,
00099    NTP_MODE_SYMMETRIC_PASSIVE = 2,
00100    NTP_MODE_CLIENT            = 3,
00101    NTP_MODE_SERVER            = 4,
00102    NTP_MODE_BROADCAST         = 5
00103 } NtpMode;
00104 
00105 
00106 //CodeWarrior or Win32 compiler?
00107 #if defined(__CWCC__) || defined(_WIN32)
00108    #pragma pack(push, 1)
00109 #endif
00110 
00111 
00112 /**
00113  * @brief Time representation
00114  **/
00115 
00116 typedef __start_packed struct
00117 {
00118    uint32_t seconds;
00119    uint32_t fraction;
00120 } __end_packed NtpTimestamp;
00121 
00122 
00123 /**
00124  * @brief NTP packet header
00125  **/
00126 
00127 typedef __start_packed struct
00128 {
00129 #ifdef _CPU_BIG_ENDIAN
00130    uint8_t li : 2;                  //0
00131    uint8_t vn : 3;
00132    uint8_t mode : 3;
00133 #else
00134    uint8_t mode : 3;                //0
00135    uint8_t vn : 3;
00136    uint8_t li : 2;
00137 #endif
00138    uint8_t stratum;                 //1
00139    uint8_t poll;                    //2
00140    int8_t precision;                //3
00141    uint32_t rootDelay;              //4-7
00142    uint32_t rootDispersion;         //8-11
00143    uint32_t referenceIdentifier;    //12-15
00144    NtpTimestamp referenceTimestamp; //16-23
00145    NtpTimestamp originateTimestamp; //24-31
00146    NtpTimestamp receiveTimestamp;   //32-39
00147    NtpTimestamp transmitTimestamp;  //40-47
00148 } __end_packed NtpHeader;
00149 
00150 
00151 /**
00152  * @brief Authentication data
00153  **/
00154 
00155 typedef __start_packed struct
00156 {
00157    uint32_t keyIdentifier;
00158    uint8_t messageDigest[16];
00159 } __end_packed NtpAuthData;
00160 
00161 
00162 //CodeWarrior or Win32 compiler?
00163 #if defined(__CWCC__) || defined(_WIN32)
00164    #pragma pack(pop)
00165 #endif
00166 
00167 
00168 /**
00169  * @brief SNTP client context
00170  **/
00171 
00172 typedef struct
00173 {
00174    Socket *socket;    ///<Underlying socket
00175    NtpHeader message; ///<Buffer where to format NTP messages
00176    systime_t t1;      ///<Time at which the NTP request was sent by the client
00177    systime_t t4;      ///<Time at which the NTP reply was received by the client
00178 } SntpClientContext;
00179 
00180 
00181 //SNTP client related functions
00182 error_t sntpClientGetTimestamp(NetInterface *interface,
00183    const IpAddr *serverIpAddr, NtpTimestamp *timestamp);
00184 
00185 error_t sntpSendRequest(SntpClientContext *context);
00186 error_t sntpWaitForResponse(SntpClientContext *context, systime_t timeout);
00187 
00188 error_t sntpParseResponse(SntpClientContext *context,
00189    const NtpHeader *message, size_t length);
00190 
00191 void sntpDumpMessage(const NtpHeader *message, size_t length);
00192 void sntpDumpTimestamp(const NtpTimestamp *timestamp);
00193