Koen Kempeneers / NTPClient

A minor bugfix. It prevents the library from entering an endless loop in case the NTP server droppes the request rather than sending a kiss of death message.

Dependents:   STM32F746_iothub_client_sample_mqtt Iot_LCD_EC iothub_client_sample_mqtt simplesample_mqtt ... more

NTPClient.cpp@0:537dcd4ff837, 2015-10-23 (annotated)

Committer:
KKempeneers
Date:
Fri Oct 23 14:52:54 2015 +0000
Revision:
0:537dcd4ff837
Minor bugfix. Initialized inEndpoint's address property to outEndpoints address. In the event of the server dropping the request instead of returning a kiss of death this prevents the library from entering in an endless loop.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
KKempeneers 0:537dcd4ff837 1 /* NTPClient.cpp */
KKempeneers 0:537dcd4ff837 2 /* Copyright (C) 2012 mbed.org, MIT License
KKempeneers 0:537dcd4ff837 3 *
KKempeneers 0:537dcd4ff837 4 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
KKempeneers 0:537dcd4ff837 5 * and associated documentation files (the "Software"), to deal in the Software without restriction,
KKempeneers 0:537dcd4ff837 6 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
KKempeneers 0:537dcd4ff837 7 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
KKempeneers 0:537dcd4ff837 8 * furnished to do so, subject to the following conditions:
KKempeneers 0:537dcd4ff837 9 *
KKempeneers 0:537dcd4ff837 10 * The above copyright notice and this permission notice shall be included in all copies or
KKempeneers 0:537dcd4ff837 11 * substantial portions of the Software.
KKempeneers 0:537dcd4ff837 12 *
KKempeneers 0:537dcd4ff837 13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
KKempeneers 0:537dcd4ff837 14 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
KKempeneers 0:537dcd4ff837 15 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
KKempeneers 0:537dcd4ff837 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
KKempeneers 0:537dcd4ff837 17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
KKempeneers 0:537dcd4ff837 18 */
KKempeneers 0:537dcd4ff837 19
KKempeneers 0:537dcd4ff837 20 //Debug is disabled by default
KKempeneers 0:537dcd4ff837 21 #if 0
KKempeneers 0:537dcd4ff837 22 //Enable debug
KKempeneers 0:537dcd4ff837 23 #define __DEBUG__
KKempeneers 0:537dcd4ff837 24 #include <cstdio>
KKempeneers 0:537dcd4ff837 25 #define DBG(x, ...) std::printf("[NTPClient : DBG]"x"\r\n", ##__VA_ARGS__);
KKempeneers 0:537dcd4ff837 26 #define WARN(x, ...) std::printf("[NTPClient : WARN]"x"\r\n", ##__VA_ARGS__);
KKempeneers 0:537dcd4ff837 27 #define ERR(x, ...) std::printf("[NTPClient : ERR]"x"\r\n", ##__VA_ARGS__);
KKempeneers 0:537dcd4ff837 28
KKempeneers 0:537dcd4ff837 29 #else
KKempeneers 0:537dcd4ff837 30 //Disable debug
KKempeneers 0:537dcd4ff837 31 #define DBG(x, ...)
KKempeneers 0:537dcd4ff837 32 #define WARN(x, ...)
KKempeneers 0:537dcd4ff837 33 #define ERR(x, ...)
KKempeneers 0:537dcd4ff837 34
KKempeneers 0:537dcd4ff837 35 #endif
KKempeneers 0:537dcd4ff837 36
KKempeneers 0:537dcd4ff837 37 #include "NTPClient.h"
KKempeneers 0:537dcd4ff837 38
KKempeneers 0:537dcd4ff837 39 #include "UDPSocket.h"
KKempeneers 0:537dcd4ff837 40
KKempeneers 0:537dcd4ff837 41 #include "mbed.h" //time() and set_time()
KKempeneers 0:537dcd4ff837 42
KKempeneers 0:537dcd4ff837 43 #define NTP_PORT 123
KKempeneers 0:537dcd4ff837 44 #define NTP_CLIENT_PORT 0 //Random port
KKempeneers 0:537dcd4ff837 45 #define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
KKempeneers 0:537dcd4ff837 46
KKempeneers 0:537dcd4ff837 47 NTPClient::NTPClient() : m_sock()
KKempeneers 0:537dcd4ff837 48 {
KKempeneers 0:537dcd4ff837 49
KKempeneers 0:537dcd4ff837 50
KKempeneers 0:537dcd4ff837 51 }
KKempeneers 0:537dcd4ff837 52
KKempeneers 0:537dcd4ff837 53 NTPResult NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
KKempeneers 0:537dcd4ff837 54 {
KKempeneers 0:537dcd4ff837 55 #ifdef __DEBUG__
KKempeneers 0:537dcd4ff837 56 time_t ctTime;
KKempeneers 0:537dcd4ff837 57 ctTime = time(NULL);
KKempeneers 0:537dcd4ff837 58 DBG("Time is set to (UTC): %s", ctime(&ctTime));
KKempeneers 0:537dcd4ff837 59 #endif
KKempeneers 0:537dcd4ff837 60
KKempeneers 0:537dcd4ff837 61 //Create & bind socket
KKempeneers 0:537dcd4ff837 62 DBG("Binding socket");
KKempeneers 0:537dcd4ff837 63 m_sock.bind(0); //Bind to a random port
KKempeneers 0:537dcd4ff837 64
KKempeneers 0:537dcd4ff837 65 m_sock.set_blocking(false, timeout); //Set not blocking
KKempeneers 0:537dcd4ff837 66
KKempeneers 0:537dcd4ff837 67 struct NTPPacket pkt;
KKempeneers 0:537dcd4ff837 68
KKempeneers 0:537dcd4ff837 69 //Now ping the server and wait for response
KKempeneers 0:537dcd4ff837 70 DBG("Ping");
KKempeneers 0:537dcd4ff837 71 //Prepare NTP Packet:
KKempeneers 0:537dcd4ff837 72 pkt.li = 0; //Leap Indicator : No warning
KKempeneers 0:537dcd4ff837 73 pkt.vn = 4; //Version Number : 4
KKempeneers 0:537dcd4ff837 74 pkt.mode = 3; //Client mode
KKempeneers 0:537dcd4ff837 75 pkt.stratum = 0; //Not relevant here
KKempeneers 0:537dcd4ff837 76 pkt.poll = 0; //Not significant as well
KKempeneers 0:537dcd4ff837 77 pkt.precision = 0; //Neither this one is
KKempeneers 0:537dcd4ff837 78
KKempeneers 0:537dcd4ff837 79 pkt.rootDelay = 0; //Or this one
KKempeneers 0:537dcd4ff837 80 pkt.rootDispersion = 0; //Or that one
KKempeneers 0:537dcd4ff837 81 pkt.refId = 0; //...
KKempeneers 0:537dcd4ff837 82
KKempeneers 0:537dcd4ff837 83 pkt.refTm_s = 0;
KKempeneers 0:537dcd4ff837 84 pkt.origTm_s = 0;
KKempeneers 0:537dcd4ff837 85 pkt.rxTm_s = 0;
KKempeneers 0:537dcd4ff837 86 pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
KKempeneers 0:537dcd4ff837 87
KKempeneers 0:537dcd4ff837 88 pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
KKempeneers 0:537dcd4ff837 89
KKempeneers 0:537dcd4ff837 90 Endpoint outEndpoint;
KKempeneers 0:537dcd4ff837 91
KKempeneers 0:537dcd4ff837 92 if( outEndpoint.set_address(host, port) < 0)
KKempeneers 0:537dcd4ff837 93 {
KKempeneers 0:537dcd4ff837 94 m_sock.close();
KKempeneers 0:537dcd4ff837 95 return NTP_DNS;
KKempeneers 0:537dcd4ff837 96 }
KKempeneers 0:537dcd4ff837 97
KKempeneers 0:537dcd4ff837 98 //Set timeout, non-blocking and wait using select
KKempeneers 0:537dcd4ff837 99 int ret = m_sock.sendTo( outEndpoint, (char*)&pkt, sizeof(NTPPacket) );
KKempeneers 0:537dcd4ff837 100 if (ret < 0 )
KKempeneers 0:537dcd4ff837 101 {
KKempeneers 0:537dcd4ff837 102 ERR("Could not send packet");
KKempeneers 0:537dcd4ff837 103 m_sock.close();
KKempeneers 0:537dcd4ff837 104 return NTP_CONN;
KKempeneers 0:537dcd4ff837 105 }
KKempeneers 0:537dcd4ff837 106
KKempeneers 0:537dcd4ff837 107 //Read response
KKempeneers 0:537dcd4ff837 108 Endpoint inEndpoint;
KKempeneers 0:537dcd4ff837 109 // Set the inEndpoint address property
KKempeneers 0:537dcd4ff837 110 inEndpoint.set_address(outEndpoint.get_address(), 0);
KKempeneers 0:537dcd4ff837 111 DBG("Pong");
KKempeneers 0:537dcd4ff837 112 do
KKempeneers 0:537dcd4ff837 113 {
KKempeneers 0:537dcd4ff837 114 ret = m_sock.receiveFrom( inEndpoint, (char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name
KKempeneers 0:537dcd4ff837 115 if(ret < 0)
KKempeneers 0:537dcd4ff837 116 {
KKempeneers 0:537dcd4ff837 117 ERR("Could not receive packet");
KKempeneers 0:537dcd4ff837 118 m_sock.close();
KKempeneers 0:537dcd4ff837 119 return NTP_CONN;
KKempeneers 0:537dcd4ff837 120 }
KKempeneers 0:537dcd4ff837 121 } while( strcmp(outEndpoint.get_address(), inEndpoint.get_address()) != 0 );
KKempeneers 0:537dcd4ff837 122
KKempeneers 0:537dcd4ff837 123 if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
KKempeneers 0:537dcd4ff837 124 {
KKempeneers 0:537dcd4ff837 125 ERR("Receive packet size does not match");
KKempeneers 0:537dcd4ff837 126 m_sock.close();
KKempeneers 0:537dcd4ff837 127 return NTP_PRTCL;
KKempeneers 0:537dcd4ff837 128 }
KKempeneers 0:537dcd4ff837 129
KKempeneers 0:537dcd4ff837 130 if( pkt.stratum == 0) //Kiss of death message : Not good !
KKempeneers 0:537dcd4ff837 131 {
KKempeneers 0:537dcd4ff837 132 ERR("Kissed to death!");
KKempeneers 0:537dcd4ff837 133 m_sock.close();
KKempeneers 0:537dcd4ff837 134 return NTP_PRTCL;
KKempeneers 0:537dcd4ff837 135 }
KKempeneers 0:537dcd4ff837 136
KKempeneers 0:537dcd4ff837 137 //Correct Endianness
KKempeneers 0:537dcd4ff837 138 pkt.refTm_s = ntohl( pkt.refTm_s );
KKempeneers 0:537dcd4ff837 139 pkt.refTm_f = ntohl( pkt.refTm_f );
KKempeneers 0:537dcd4ff837 140 pkt.origTm_s = ntohl( pkt.origTm_s );
KKempeneers 0:537dcd4ff837 141 pkt.origTm_f = ntohl( pkt.origTm_f );
KKempeneers 0:537dcd4ff837 142 pkt.rxTm_s = ntohl( pkt.rxTm_s );
KKempeneers 0:537dcd4ff837 143 pkt.rxTm_f = ntohl( pkt.rxTm_f );
KKempeneers 0:537dcd4ff837 144 pkt.txTm_s = ntohl( pkt.txTm_s );
KKempeneers 0:537dcd4ff837 145 pkt.txTm_f = ntohl( pkt.txTm_f );
KKempeneers 0:537dcd4ff837 146
KKempeneers 0:537dcd4ff837 147 //Compute offset, see RFC 4330 p.13
KKempeneers 0:537dcd4ff837 148 uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
KKempeneers 0:537dcd4ff837 149 int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
KKempeneers 0:537dcd4ff837 150 DBG("Sent @%ul", pkt.txTm_s);
KKempeneers 0:537dcd4ff837 151 DBG("Offset: %lld", offset);
KKempeneers 0:537dcd4ff837 152 //Set time accordingly
KKempeneers 0:537dcd4ff837 153 set_time( time(NULL) + offset );
KKempeneers 0:537dcd4ff837 154
KKempeneers 0:537dcd4ff837 155 #ifdef __DEBUG__
KKempeneers 0:537dcd4ff837 156 ctTime = time(NULL);
KKempeneers 0:537dcd4ff837 157 DBG("Time is now (UTC): %s", ctime(&ctTime));
KKempeneers 0:537dcd4ff837 158 #endif
KKempeneers 0:537dcd4ff837 159
KKempeneers 0:537dcd4ff837 160 m_sock.close();
KKempeneers 0:537dcd4ff837 161
KKempeneers 0:537dcd4ff837 162 return NTP_OK;
KKempeneers 0:537dcd4ff837 163 }
KKempeneers 0:537dcd4ff837 164