File content as of revision 0:a56239ae90c2:

/* NTPClient.cpp */
/* Copyright (C) 2012 mbed.org, MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#if 1
//Enable debug
#define __DEBUG__
#include <cstdio>
#define DBG(x, ...) std::printf("[NTPClient : DBG]"x"\r\n", ##__VA_ARGS__); 
#define WARN(x, ...) std::printf("[NTPClient : WARN]"x"\r\n", ##__VA_ARGS__); 
#define ERR(x, ...) std::printf("[NTPClient : ERR]"x"\r\n", ##__VA_ARGS__); 

#else
//Disable debug
#define DBG(x, ...) 
#define WARN(x, ...)
#define ERR(x, ...) 
#endif

#include "NTPClient.h"

#include "mbed.h" //time() and set_time()

NTPClient::NTPClient() : m_sock()
{
    reset();
    
    mQuerySent = false;
    mResponseReceived = false;
    mConversationComplete = true;
    mStartTime = 0;
}

void NTPClient::reset()
{
    if (outEndpoint)
    {
        delete outEndpoint;
    }
    if (inEndpoint)
    {
        delete inEndpoint;
    }
    outEndpoint = NULL;
    inEndpoint = NULL;
    
    m_sock.close();
}

void NTPClient::process_result()
{
    //Correct Endianness
    pkt.refTm_s = ntohl( pkt.refTm_s );
    pkt.refTm_f = ntohl( pkt.refTm_f );
    pkt.origTm_s = ntohl( pkt.origTm_s );
    pkt.origTm_f = ntohl( pkt.origTm_f );
    pkt.rxTm_s = ntohl( pkt.rxTm_s );
    pkt.rxTm_f = ntohl( pkt.rxTm_f );
    pkt.txTm_s = ntohl( pkt.txTm_s );
    pkt.txTm_f = ntohl( pkt.txTm_f );
    
    //Compute offset, see RFC 4330 p.13
    uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
    int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
    DBG("Received @%ul", pkt.txTm_s);
    DBG("Offset: %lld", offset);
    //Set time accordingly
    set_time( time(NULL) + offset );
    
    #ifdef __DEBUG__
    time_t ctTime;
    ctTime = time(NULL);
    DBG("Time is now (UTC): %s", ctime(&ctTime));
    #endif
}

int NTPClient::update()
{
    int ntp_result = NTP_WAIT;
    bool conversationComplete = true;
    
    if (mQuerySent && !mConversationComplete)
    {
        // Listen for a response from the NTP server.
        int ret = m_sock.recvfrom( inEndpoint, (char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name
        
        if (ret == NSAPI_ERROR_WOULD_BLOCK)
        {
            //DBG("Waiting...");
            
            // Check for response timeout.
            if ((time(NULL) - mStartTime) < mTimeout)
            {
                conversationComplete = false;
            }
            else
            {
                DBG("Timeout.\n");
                ntp_result = NTP_TIMEOUT;
            }
        }
        else if(ret < 0)
        {
            ERR("Could not receive packet");
            ntp_result = NTP_CONN;
        }
        else if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
        {
            ERR("Received packet size does not match");
            ntp_result = NTP_PRTCL;
        }
        else if( pkt.stratum == 0)  //Kiss of death
        {
            ERR("Kissed to death!");
            ntp_result = NTP_PRTCL;
        }
        else
        {
            process_result();
            ntp_result = NTP_OK;
        }
        
        if (conversationComplete)
        {
            reset();        
            mConversationComplete = true;
        }
    }
    
    return ntp_result;
}

NTPResult NTPClient::setTime(EthernetInterface* stack, const char* host, uint16_t port, uint32_t timeout)
{
    mQuerySent = false;
    mResponseReceived = false;
    mConversationComplete = false;
    
    mStartTime = time(NULL);
    mTimeout = timeout;
    
#ifdef __DEBUG__
  time_t ctTime;
  ctTime = time(NULL);
  DBG("Time is set to (UTC): %s", ctime(&ctTime));
#endif

  //Create & bind socket
  m_sock.open(stack);
  DBG("Binding socket: %d", m_sock.bind(NTP_CLIENT_PORT)); //Bind to a random port
  m_sock.set_blocking(false); //Set not blocking

  //Now ping the server and wait for response
  DBG("Ping");
  //Prepare NTP Packet:
  pkt.li = 0; //Leap Indicator : No warning
  pkt.vn = 4; //Version Number : 4
  pkt.mode = 3; //Client mode
  pkt.stratum = 0; //Not relevant here
  pkt.poll = 0; //Not significant as well
  pkt.precision = 0; //Neither this one is

  pkt.rootDelay = 0; //Or this one
  pkt.rootDispersion = 0; //Or that one
  pkt.refId = 0; //...

  pkt.refTm_s = 0;
  pkt.origTm_s = 0;
  pkt.rxTm_s = 0;
  pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE

  pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;

  outEndpoint = new SocketAddress(host, port);
  inEndpoint = new SocketAddress(host, 0);
  
  //Set timeout, non-blocking and wait using select
  DBG("Send packet to %s:%d", host, port);
  int ret = m_sock.sendto(*outEndpoint, (void*)&pkt, sizeof(NTPPacket));
  if (ret < 0 )
  {
    ERR("Could not send packet %d\n", ret);
    m_sock.close();
    return NTP_CONN;
  }
  DBG("Sent...");
  
  mQuerySent = true;

  return NTP_OK;
}