sntp_client.c

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/**
 * @file sntp_client.c
 * @brief SNTP client (Simple Network Time Protocol)
 *
 * @section License
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Copyright (C) 2010-2025 Oryx Embedded SARL. All rights reserved.
 *
 * This file is part of CycloneTCP Open.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * @section Description
 *
 * The Simple Network Time Protocol is used to synchronize computer clocks
 * in the Internet. Refer to RFC 4330 for more details
 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.5.0
 **/
 
//Switch to the appropriate trace level
#define TRACE_LEVEL SNTP_TRACE_LEVEL
 
//Dependencies
#include "core/net.h"
#include "sntp/sntp_client.h"
#include "sntp/sntp_client_misc.h"
#include "debug.h"
 
//Check TCP/IP stack configuration
#if (SNTP_CLIENT_SUPPORT == ENABLED)
 
 
/**
 * @brief Initialize SNTP client context
 * @param[in] context Pointer to the SNTP client context
 * @return Error code
 **/
 
error_t sntpClientInit(SntpClientContext *context)
{
   //Make sure the SNTP client context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Clear SNTP client context
   osMemset(context, 0, sizeof(SntpClientContext));
 
   //Initialize SNTP client state
   context->state = SNTP_CLIENT_STATE_INIT;
 
   //Default protocol version
   context->version = NTP_VERSION_3;
   //Default timeout
   context->timeout = SNTP_CLIENT_DEFAULT_TIMEOUT;
 
   //Successful initialization
   return NO_ERROR;
}
 
 
/**
 * @brief Set the NTP protocol version to be used
 * @param[in] context Pointer to the SNTP client context
 * @param[in] version NTP protocol version (2 or 3)
 * @return Error code
 **/
 
error_t sntpClientSetVersion(SntpClientContext *context, NtpVersion version)
{
   //Make sure the SNTP client context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Check NTP version
   if(version != NTP_VERSION_3 && version != NTP_VERSION_4)
      return ERROR_INVALID_VERSION;
 
   //Save the protocol version to be used
   context->version = version;
 
   //Successful initialization
   return NO_ERROR;
}
 
 
/**
 * @brief Set communication timeout
 * @param[in] context Pointer to the SNTP client context
 * @param[in] timeout Timeout value, in milliseconds
 * @return Error code
 **/
 
error_t sntpClientSetTimeout(SntpClientContext *context, systime_t timeout)
{
   //Make sure the SNTP client context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Save timeout value
   context->timeout = timeout;
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Bind the SNTP client to a particular network interface
 * @param[in] context Pointer to the SNTP client context
 * @param[in] interface Network interface to be used
 * @return Error code
 **/
 
error_t sntpClientBindToInterface(SntpClientContext *context,
   NetInterface *interface)
{
   //Make sure the SNTP client context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Explicitly associate the SNTP client with the specified interface
   context->interface = interface;
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Specify the IP address of the NTP server
 * @param[in] context Pointer to the SNTP client context
 * @param[in] serverIpAddr IP address of the NTP server
 * @param[in] serverPort Port number
 * @return Error code
 **/
 
error_t sntpClientSetServerAddr(SntpClientContext *context,
   const IpAddr *serverIpAddr, uint16_t serverPort)
{
   //Check parameters
   if(context == NULL || serverIpAddr == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Save the IP address and the port number of the NTP server
   context->serverIpAddr = *serverIpAddr;
   context->serverPort = serverPort;
 
   //Close UDP socket
   sntpClientCloseConnection(context);
   //Revert to default state
   context->state = SNTP_CLIENT_STATE_INIT;
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Retrieve current time from NTP server
 * @param[in] context Pointer to the SNTP client context
 * @param[out] timestamp Pointer to the NTP timestamp
 * @return Error code
 **/
 
error_t sntpClientGetTimestamp(SntpClientContext *context,
   NtpTimestamp *timestamp)
{
   error_t error;
 
   //Check parameters
   if(context == NULL || timestamp == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Initialize status code
   error = NO_ERROR;
 
   //Send NTP request and wait for server's response
   while(!error)
   {
      //Check current state
      if(context->state == SNTP_CLIENT_STATE_INIT)
      {
         //Open UDP socket
         error = sntpClientOpenConnection(context);
 
         //Check status code
         if(!error)
         {
            //Save current time
            context->startTime = osGetSystemTime();
            //Initialize retransmission timeout
            context->retransmitTimeout = SNTP_CLIENT_INIT_RETRANSMIT_TIMEOUT;
 
            //Send the request to the designated NTP server
            context->state = SNTP_CLIENT_STATE_SENDING;
         }
      }
      else if(context->state == SNTP_CLIENT_STATE_SENDING)
      {
         //Send the request to the designated NTP server
         error = sntpClientSendRequest(context);
      }
      else if(context->state == SNTP_CLIENT_STATE_RECEIVING)
      {
         //Wait for server's response
         error = sntpClientReceiveResponse(context);
      }
      else if(context->state == SNTP_CLIENT_STATE_COMPLETE)
      {
         //Extract NTP timestamp from server's response
         error = sntpClientParseResponse(context, timestamp);
         //We are done
         break;
      }
      else
      {
         //Invalid state
         error = ERROR_WRONG_STATE;
      }
   }
 
   //Check status code
   if(error != ERROR_WOULD_BLOCK)
   {
      //Close UDP socket
      sntpClientCloseConnection(context);
      //Revert to default state
      context->state = SNTP_CLIENT_STATE_INIT;
   }
 
   //Return status code
   return error;
}
 
 
/**
 * @brief Retrieve the kiss code from a Kiss-of-Death message
 * @param[in] context Pointer to the SNTP client context
 * @return Kiss code
 **/
 
uint32_t sntpClientGetKissCode(SntpClientContext *context)
{
   uint32_t kissCode;
 
   //Make sure the SNTP client context is valid
   if(context != NULL)
   {
      //Get kiss code
      kissCode = context->kissCode;
   }
   else
   {
      //The SNTP client context is not valid
      kissCode = 0;
   }
 
   //Return kiss code
   return kissCode;
}
 
 
/**
 * @brief Release SNTP client context
 * @param[in] context Pointer to the SNTP client context
 **/
 
void sntpClientDeinit(SntpClientContext *context)
{
   //Make sure the SNTP client context is valid
   if(context != NULL)
   {
      //Close UDP socket
      sntpClientCloseConnection(context);
 
      //Clear SNTP client context
      osMemset(context, 0, sizeof(SntpClientContext));
   }
}
 
#endif