David Smart / NTPClient

NTP Client for the mbed networking libraries. The small change to this version is that there can be only one cause for the return value zero.

Dependents:   WattEye

Fork of NTPClient by Donatien Garnier

NTPClient.cpp@2:9a64a50df235, 2012-08-05 (annotated)

Committer:
donatien
Date:
Sun Aug 05 15:36:47 2012 +0000
Revision:
2:9a64a50df235
Parent:
1:b221a8765b3f
Child:
3:17d8bad407cc
Updated to use latest Socket API

Who changed what in which revision?

UserRevisionLine numberNew contents of line
donatien 0:04a82df0f587 1 /* NTPClient.cpp */
donatien 2:9a64a50df235 2 /* Copyright (C) 2012 mbed.org, MIT License
donatien 2:9a64a50df235 3 *
donatien 2:9a64a50df235 4 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
donatien 2:9a64a50df235 5 * and associated documentation files (the "Software"), to deal in the Software without restriction,
donatien 2:9a64a50df235 6 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
donatien 2:9a64a50df235 7 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
donatien 2:9a64a50df235 8 * furnished to do so, subject to the following conditions:
donatien 2:9a64a50df235 9 *
donatien 2:9a64a50df235 10 * The above copyright notice and this permission notice shall be included in all copies or
donatien 2:9a64a50df235 11 * substantial portions of the Software.
donatien 2:9a64a50df235 12 *
donatien 2:9a64a50df235 13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
donatien 2:9a64a50df235 14 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
donatien 2:9a64a50df235 15 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
donatien 2:9a64a50df235 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
donatien 2:9a64a50df235 17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
donatien 2:9a64a50df235 18 */
donatien 0:04a82df0f587 19
donatien 2:9a64a50df235 20 //Debug is disabled by default
donatien 2:9a64a50df235 21 #if
donatien 2:9a64a50df235 22 //Enable debug
donatien 2:9a64a50df235 23 #define __DEBUG__
donatien 2:9a64a50df235 24 #include <cstdio>
donatien 2:9a64a50df235 25 #define DBG(x, ...) std::printf("[NTPClient : DBG]"x"\r\n", ##__VA_ARGS__);
donatien 2:9a64a50df235 26 #define WARN(x, ...) std::printf("[NTPClient : WARN]"x"\r\n", ##__VA_ARGS__);
donatien 2:9a64a50df235 27 #define ERR(x, ...) std::printf("[NTPClient : ERR]"x"\r\n", ##__VA_ARGS__);
donatien 0:04a82df0f587 28
donatien 2:9a64a50df235 29 #else
donatien 2:9a64a50df235 30 //Disable debug
donatien 2:9a64a50df235 31 #define DBG(x, ...)
donatien 2:9a64a50df235 32 #define WARN(x, ...)
donatien 2:9a64a50df235 33 #define ERR(x, ...)
donatien 2:9a64a50df235 34
donatien 0:04a82df0f587 35 #endif
donatien 0:04a82df0f587 36
donatien 0:04a82df0f587 37 #include "NTPClient.h"
donatien 0:04a82df0f587 38
donatien 1:b221a8765b3f 39 #include "UDPSocket.h"
donatien 1:b221a8765b3f 40
donatien 0:04a82df0f587 41 #include "mbed.h" //time() and set_time()
donatien 0:04a82df0f587 42
donatien 0:04a82df0f587 43 #define NTP_PORT 123
donatien 0:04a82df0f587 44 #define NTP_CLIENT_PORT 0 //Random port
donatien 0:04a82df0f587 45 #define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
donatien 0:04a82df0f587 46
donatien 2:9a64a50df235 47 NTPClient::NTPClient() : m_sock()
donatien 0:04a82df0f587 48 {
donatien 0:04a82df0f587 49
donatien 0:04a82df0f587 50
donatien 0:04a82df0f587 51 }
donatien 0:04a82df0f587 52
donatien 2:9a64a50df235 53 NTPResult NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
donatien 0:04a82df0f587 54 {
donatien 2:9a64a50df235 55 #ifdef __DEBUG__
donatien 0:04a82df0f587 56 time_t ctTime;
donatien 0:04a82df0f587 57 ctTime = time(NULL);
donatien 2:9a64a50df235 58 DBG("Time is set to (UTC): %s", ctime(&ctTime));
donatien 0:04a82df0f587 59 #endif
donatien 0:04a82df0f587 60
donatien 1:b221a8765b3f 61 //Create & bind socket
donatien 2:9a64a50df235 62 DBG("Binding socket");
donatien 2:9a64a50df235 63 m_sock.bind(0); //Bind to a random port
donatien 2:9a64a50df235 64
donatien 2:9a64a50df235 65 m_sock.set_blocking(true, timeout); //Set blocking
donatien 0:04a82df0f587 66
donatien 0:04a82df0f587 67 struct NTPPacket pkt;
donatien 0:04a82df0f587 68
donatien 0:04a82df0f587 69 //Now ping the server and wait for response
donatien 0:04a82df0f587 70 DBG("Ping");
donatien 0:04a82df0f587 71 //Prepare NTP Packet:
donatien 0:04a82df0f587 72 pkt.li = 0; //Leap Indicator : No warning
donatien 0:04a82df0f587 73 pkt.vn = 4; //Version Number : 4
donatien 0:04a82df0f587 74 pkt.mode = 3; //Client mode
donatien 0:04a82df0f587 75 pkt.stratum = 0; //Not relevant here
donatien 0:04a82df0f587 76 pkt.poll = 0; //Not significant as well
donatien 0:04a82df0f587 77 pkt.precision = 0; //Neither this one is
donatien 0:04a82df0f587 78
donatien 0:04a82df0f587 79 pkt.rootDelay = 0; //Or this one
donatien 0:04a82df0f587 80 pkt.rootDispersion = 0; //Or that one
donatien 0:04a82df0f587 81 pkt.refId = 0; //...
donatien 0:04a82df0f587 82
donatien 0:04a82df0f587 83 pkt.refTm_s = 0;
donatien 0:04a82df0f587 84 pkt.origTm_s = 0;
donatien 0:04a82df0f587 85 pkt.rxTm_s = 0;
donatien 0:04a82df0f587 86 pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
donatien 0:04a82df0f587 87
donatien 0:04a82df0f587 88 pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
donatien 0:04a82df0f587 89
donatien 2:9a64a50df235 90 Endpoint outEndpoint;
donatien 2:9a64a50df235 91
donatien 2:9a64a50df235 92 if( outEndpoint.set_address(host, port) < 0)
donatien 2:9a64a50df235 93 {
donatien 2:9a64a50df235 94 m_sock.close();
donatien 2:9a64a50df235 95 return NTP_DNS;
donatien 2:9a64a50df235 96 }
donatien 2:9a64a50df235 97
donatien 0:04a82df0f587 98 //Set timeout, non-blocking and wait using select
donatien 2:9a64a50df235 99 int ret = m_sock.sendTo( outEndpoint, (char*)&pkt, sizeof(NTPPacket) );
donatien 2:9a64a50df235 100 if (ret < 0 )
donatien 0:04a82df0f587 101 {
donatien 0:04a82df0f587 102 ERR("Could not send packet");
donatien 2:9a64a50df235 103 m_sock.close();
donatien 2:9a64a50df235 104 return NTP_CONN;
donatien 0:04a82df0f587 105 }
donatien 0:04a82df0f587 106
donatien 0:04a82df0f587 107 //Read response
donatien 2:9a64a50df235 108 Endpoint inEndpoint;
donatien 2:9a64a50df235 109
donatien 0:04a82df0f587 110 DBG("Pong");
donatien 0:04a82df0f587 111 do
donatien 0:04a82df0f587 112 {
donatien 2:9a64a50df235 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
donatien 0:04a82df0f587 114 if(ret < 0)
donatien 0:04a82df0f587 115 {
donatien 0:04a82df0f587 116 ERR("Could not receive packet");
donatien 2:9a64a50df235 117 m_sock.close();
donatien 2:9a64a50df235 118 return NTP_CONN;
donatien 0:04a82df0f587 119 }
donatien 2:9a64a50df235 120 } while( strcmp(outEndpoint.get_address(), inEndpoint.get_address()) != 0 );
donatien 0:04a82df0f587 121
donatien 0:04a82df0f587 122 if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
donatien 0:04a82df0f587 123 {
donatien 0:04a82df0f587 124 ERR("Receive packet size does not match");
donatien 2:9a64a50df235 125 m_sock.close();
donatien 2:9a64a50df235 126 return NTP_PRTCL;
donatien 0:04a82df0f587 127 }
donatien 0:04a82df0f587 128
donatien 0:04a82df0f587 129 if( pkt.stratum == 0) //Kiss of death message : Not good !
donatien 0:04a82df0f587 130 {
donatien 0:04a82df0f587 131 ERR("Kissed to death!");
donatien 2:9a64a50df235 132 m_sock.close();
donatien 2:9a64a50df235 133 return NTP_PRTCL;
donatien 0:04a82df0f587 134 }
donatien 0:04a82df0f587 135
donatien 0:04a82df0f587 136 //Correct Endianness
donatien 0:04a82df0f587 137 pkt.refTm_s = ntohl( pkt.refTm_s );
donatien 0:04a82df0f587 138 pkt.refTm_f = ntohl( pkt.refTm_f );
donatien 0:04a82df0f587 139 pkt.origTm_s = ntohl( pkt.origTm_s );
donatien 0:04a82df0f587 140 pkt.origTm_f = ntohl( pkt.origTm_f );
donatien 0:04a82df0f587 141 pkt.rxTm_s = ntohl( pkt.rxTm_s );
donatien 0:04a82df0f587 142 pkt.rxTm_f = ntohl( pkt.rxTm_f );
donatien 0:04a82df0f587 143 pkt.txTm_s = ntohl( pkt.txTm_s );
donatien 0:04a82df0f587 144 pkt.txTm_f = ntohl( pkt.txTm_f );
donatien 0:04a82df0f587 145
donatien 0:04a82df0f587 146 //Compute offset, see RFC 4330 p.13
donatien 0:04a82df0f587 147 uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
donatien 0:04a82df0f587 148 int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
donatien 0:04a82df0f587 149 DBG("Sent @%ul", pkt.txTm_s);
donatien 2:9a64a50df235 150 DBG("Offset: %lld", offset);
donatien 0:04a82df0f587 151 //Set time accordingly
donatien 0:04a82df0f587 152 set_time( time(NULL) + offset );
donatien 0:04a82df0f587 153
donatien 2:9a64a50df235 154 #ifdef __DEBUG__
donatien 0:04a82df0f587 155 ctTime = time(NULL);
donatien 2:9a64a50df235 156 DBG("Time is now (UTC): %s", ctime(&ctTime));
donatien 0:04a82df0f587 157 #endif
donatien 0:04a82df0f587 158
donatien 2:9a64a50df235 159 m_sock.close();
donatien 0:04a82df0f587 160
donatien 2:9a64a50df235 161 return NTP_OK;
donatien 0:04a82df0f587 162 }
donatien 0:04a82df0f587 163