File content as of revision 0:c2440e1c92cc:

/* 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.
 */

//Debug is disabled by default
#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 "cmsis.h"
#define htons(x)      __REV16(x)
#define htonl(x)      __REV(x)
#define ntohl(x)      __REV(x)


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

#define NTP_PORT 123
#define NTP_CLIENT_PORT 0 //Random port
#define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)

NTPClient::NTPClient() : m_sock()
{


}

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

    //Create & bind socket
    DBG("Binding socket");
    m_sock.connect("0.pool.ntp.org",123,"UDP"); //Bind to a random port

    //m_sock.set_blocking(false, timeout); //Set not blocking

    struct NTPPacket pkt;

    //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;

    //Set timeout, non-blocking and wait using select
    int ret = m_sock.send((char*)&pkt, sizeof(NTPPacket) );
    if (ret < 0 ) {
        ERR("Could not send packet");
        m_sock.close();
        return NTP_CONN;
    }

    DBG("Pong");
    ret = m_sock.receive((char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name
    if(ret < 0) {
        ERR("Could not receive packet");
        m_sock.close();
        return NTP_CONN;
    }

    if(ret < sizeof(NTPPacket)) { //TODO: Accept chunks
        ERR("Receive packet size does not match");
        m_sock.close();
        return NTP_PRTCL;
    }

    if( pkt.stratum == 0) { //Kiss of death message : Not good !
        ERR("Kissed to death!");
        m_sock.close();
        return NTP_PRTCL;
    }

    //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("Sent @%ul", pkt.txTm_s);
    DBG("Offset: %lld", offset);
    //Set time accordingly
    set_time( time(NULL) + offset );

#ifdef __DEBUG__
    ctTime = time(NULL);
    DBG("Time is now (UTC): %s", ctime(&ctTime));
#endif

    m_sock.close();

    return NTP_OK;
}