tmk_core/tool/mbed/mbed-sdk/libraries/tests/net/protocols/NTPClient_HelloWorld/NTPClient/NTPClient.cpp

   1 /* NTPClient.cpp */
   2 /* Copyright (C) 2012 mbed.org, MIT License
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
   5  * and associated documentation files (the "Software"), to deal in the Software without restriction,
   6  * including without limitation the rights to use, copy, modify, merge, publish, distribute,
   7  * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
   8  * furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice shall be included in all copies or
  11  * substantial portions of the Software.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
  14  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  16  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  17  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  18  */
  19
  20 //Debug is disabled by default
  21 #if 0
  22 //Enable debug
  23 #define __DEBUG__
  24 #include <cstdio>
  25 #define DBG(x, ...) std::printf("[NTPClient : DBG]"x"\r\n", ##__VA_ARGS__);
  26 #define WARN(x, ...) std::printf("[NTPClient : WARN]"x"\r\n", ##__VA_ARGS__);
  27 #define ERR(x, ...) std::printf("[NTPClient : ERR]"x"\r\n", ##__VA_ARGS__);
  28
  29 #else
  30 //Disable debug
  31 #define DBG(x, ...)
  32 #define WARN(x, ...)
  33 #define ERR(x, ...)
  34
  35 #endif
  36
  37 #include "NTPClient.h"
  38
  39 #include "UDPSocket.h"
  40
  41 #include "mbed.h" //time() and set_time()
  42
  43 #define NTP_PORT 123
  44 #define NTP_CLIENT_PORT 0 //Random port
  45 #define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
  46
  47 NTPClient::NTPClient() : m_sock()
  48 {
  49
  50
  51 }
  52
  53 NTPResult NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
  54 {
  55 #ifdef __DEBUG__
  56   time_t ctTime;
  57   ctTime = time(NULL);
  58   DBG("Time is set to (UTC): %s", ctime(&ctTime));
  59 #endif
  60
  61   //Create & bind socket
  62   DBG("Binding socket");
  63   m_sock.bind(0); //Bind to a random port
  64
  65   m_sock.set_blocking(false, timeout); //Set not blocking
  66
  67   struct NTPPacket pkt;
  68
  69   //Now ping the server and wait for response
  70   DBG("Ping");
  71   //Prepare NTP Packet:
  72   pkt.li = 0; //Leap Indicator : No warning
  73   pkt.vn = 4; //Version Number : 4
  74   pkt.mode = 3; //Client mode
  75   pkt.stratum = 0; //Not relevant here
  76   pkt.poll = 0; //Not significant as well
  77   pkt.precision = 0; //Neither this one is
  78
  79   pkt.rootDelay = 0; //Or this one
  80   pkt.rootDispersion = 0; //Or that one
  81   pkt.refId = 0; //...
  82
  83   pkt.refTm_s = 0;
  84   pkt.origTm_s = 0;
  85   pkt.rxTm_s = 0;
  86   pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
  87
  88   pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
  89
  90   Endpoint outEndpoint;
  91
  92   if( outEndpoint.set_address(host, port) < 0)
  93   {
  94     m_sock.close();
  95     return NTP_DNS;
  96   }
  97
  98   //Set timeout, non-blocking and wait using select
  99   int ret = m_sock.sendTo( outEndpoint, (char*)&pkt, sizeof(NTPPacket) );
 100   if (ret < 0 )
 101   {
 102     ERR("Could not send packet");
 103     m_sock.close();
 104     return NTP_CONN;
 105   }
 106
 107   //Read response
 108   Endpoint inEndpoint;
 109
 110   DBG("Pong");
 111   do
 112   {
 113     ret = m_sock.receiveFrom( inEndpoint, (char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name
 114     if(ret < 0)
 115     {
 116       ERR("Could not receive packet");
 117       m_sock.close();
 118       return NTP_CONN;
 119     }
 120   } while( strcmp(outEndpoint.get_address(), inEndpoint.get_address()) != 0 );
 121
 122   if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
 123   {
 124     ERR("Receive packet size does not match");
 125     m_sock.close();
 126     return NTP_PRTCL;
 127   }
 128
 129   if( pkt.stratum == 0)  //Kiss of death message : Not good !
 130   {
 131     ERR("Kissed to death!");
 132     m_sock.close();
 133     return NTP_PRTCL;
 134   }
 135
 136   //Correct Endianness
 137   pkt.refTm_s = ntohl( pkt.refTm_s );
 138   pkt.refTm_f = ntohl( pkt.refTm_f );
 139   pkt.origTm_s = ntohl( pkt.origTm_s );
 140   pkt.origTm_f = ntohl( pkt.origTm_f );
 141   pkt.rxTm_s = ntohl( pkt.rxTm_s );
 142   pkt.rxTm_f = ntohl( pkt.rxTm_f );
 143   pkt.txTm_s = ntohl( pkt.txTm_s );
 144   pkt.txTm_f = ntohl( pkt.txTm_f );
 145
 146   //Compute offset, see RFC 4330 p.13
 147   uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
 148   int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
 149   DBG("Sent @%ul", pkt.txTm_s);
 150   DBG("Offset: %lld", offset);
 151   //Set time accordingly
 152   set_time( time(NULL) + offset );
 153
 154 #ifdef __DEBUG__
 155   ctTime = time(NULL);
 156   DBG("Time is now (UTC): %s", ctime(&ctTime));
 157 #endif
 158
 159   m_sock.close();
 160
 161   return NTP_OK;
 162 }
 163