John Durrell / NTPClient

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of NTPClient by Dieter Graef

NTPClient.cpp@2:eda6db3ada54, 2018-02-25 (annotated)

Committer:
jhd25
Date:
Sun Feb 25 11:13:37 2018 +0000
Revision:
2:eda6db3ada54
Parent:
1:52e0f030d00e 
Changed to stdint.h from cstdint

Who changed what in which revision?

UserRevisionLine numberNew contents of line
DieterGraef 0:584a18640e84 1 /* NTPClient.cpp */
DieterGraef 0:584a18640e84 2 /* Copyright (C) 2012 mbed.org, MIT License
DieterGraef 0:584a18640e84 3 *
DieterGraef 0:584a18640e84 4 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
DieterGraef 0:584a18640e84 5 * and associated documentation files (the "Software"), to deal in the Software without restriction,
DieterGraef 0:584a18640e84 6 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
DieterGraef 0:584a18640e84 7 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
DieterGraef 0:584a18640e84 8 * furnished to do so, subject to the following conditions:
DieterGraef 0:584a18640e84 9 *
DieterGraef 0:584a18640e84 10 * The above copyright notice and this permission notice shall be included in all copies or
DieterGraef 0:584a18640e84 11 * substantial portions of the Software.
DieterGraef 0:584a18640e84 12 *
DieterGraef 0:584a18640e84 13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
DieterGraef 0:584a18640e84 14 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
DieterGraef 0:584a18640e84 15 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DieterGraef 0:584a18640e84 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
DieterGraef 0:584a18640e84 17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
DieterGraef 0:584a18640e84 18 */
DieterGraef 0:584a18640e84 19
DieterGraef 0:584a18640e84 20 #include "NTPClient.h"
jhd25 1:52e0f030d00e 21 #include "EthernetInterface.h"
DieterGraef 0:584a18640e84 22 #include "UDPSocket.h"
DieterGraef 0:584a18640e84 23 #include "mbed.h" //time() and set_time()
jhd25 1:52e0f030d00e 24 #include "lwip/opt.h"
jhd25 1:52e0f030d00e 25 #include "lwip/def.h"
DieterGraef 0:584a18640e84 26 #define NTP_PORT 123
DieterGraef 0:584a18640e84 27 #define NTP_CLIENT_PORT 0 //Random port
DieterGraef 0:584a18640e84 28 #define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
DieterGraef 0:584a18640e84 29
jhd25 1:52e0f030d00e 30 NTPClient::NTPClient(EthernetInterface& net_stack) : m_sock(&net_stack)
DieterGraef 0:584a18640e84 31 {
jhd25 1:52e0f030d00e 32 EthernetInterface nst = net_stack;
DieterGraef 0:584a18640e84 33
DieterGraef 0:584a18640e84 34 }
DieterGraef 0:584a18640e84 35
DieterGraef 0:584a18640e84 36 NTPResult NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
DieterGraef 0:584a18640e84 37 {
DieterGraef 0:584a18640e84 38
DieterGraef 0:584a18640e84 39 //Create & bind socket
jhd25 1:52e0f030d00e 40 SocketAddress inEndpoint("0.0.0.0", 0);
jhd25 1:52e0f030d00e 41 m_sock.bind(inEndpoint); //Bind to a random port
jhd25 1:52e0f030d00e 42 m_sock.set_blocking(false); //Set not blocking
jhd25 1:52e0f030d00e 43 SocketAddress outEndpoint(&nst,host,port);
DieterGraef 0:584a18640e84 44 struct NTPPacket pkt;
DieterGraef 0:584a18640e84 45
DieterGraef 0:584a18640e84 46 //Now ping the server and wait for response
DieterGraef 0:584a18640e84 47 //Prepare NTP Packet:
DieterGraef 0:584a18640e84 48 pkt.li = 0; //Leap Indicator : No warning
DieterGraef 0:584a18640e84 49 pkt.vn = 4; //Version Number : 4
DieterGraef 0:584a18640e84 50 pkt.mode = 3; //Client mode
DieterGraef 0:584a18640e84 51 pkt.stratum = 0; //Not relevant here
DieterGraef 0:584a18640e84 52 pkt.poll = 0; //Not significant as well
DieterGraef 0:584a18640e84 53 pkt.precision = 0; //Neither this one is
DieterGraef 0:584a18640e84 54
DieterGraef 0:584a18640e84 55 pkt.rootDelay = 0; //Or this one
DieterGraef 0:584a18640e84 56 pkt.rootDispersion = 0; //Or that one
DieterGraef 0:584a18640e84 57 pkt.refId = 0; //...
DieterGraef 0:584a18640e84 58
DieterGraef 0:584a18640e84 59 pkt.refTm_s = 0;
DieterGraef 0:584a18640e84 60 pkt.origTm_s = 0;
DieterGraef 0:584a18640e84 61 pkt.rxTm_s = 0;
DieterGraef 0:584a18640e84 62 pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
DieterGraef 0:584a18640e84 63
DieterGraef 0:584a18640e84 64 pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
DieterGraef 0:584a18640e84 65
DieterGraef 0:584a18640e84 66 //Set timeout, non-blocking and wait using select
jhd25 1:52e0f030d00e 67 int ret = m_sock.sendto(outEndpoint, &pkt, sizeof(NTPPacket));
jhd25 1:52e0f030d00e 68
DieterGraef 0:584a18640e84 69 if (ret < 0 )
DieterGraef 0:584a18640e84 70 {
DieterGraef 0:584a18640e84 71 m_sock.close();
DieterGraef 0:584a18640e84 72 return NTP_CONN;
DieterGraef 0:584a18640e84 73 }
DieterGraef 0:584a18640e84 74
DieterGraef 0:584a18640e84 75 //Read response
DieterGraef 0:584a18640e84 76 // Set the inEndpoint address property
jhd25 2:eda6db3ada54 77 int tries =0;
jhd25 2:eda6db3ada54 78 while (true) {
jhd25 1:52e0f030d00e 79 ret = m_sock.recvfrom( &inEndpoint, (char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name
jhd25 1:52e0f030d00e 80 wait(0.01);
jhd25 1:52e0f030d00e 81 if((ret < 0 && ret != -3001) || tries >100)
DieterGraef 0:584a18640e84 82 {
DieterGraef 0:584a18640e84 83 m_sock.close();
DieterGraef 0:584a18640e84 84 return NTP_CONN;
DieterGraef 0:584a18640e84 85 }
jhd25 1:52e0f030d00e 86 if (strcmp(outEndpoint.get_ip_address(), inEndpoint.get_ip_address()) == 0 ) break;
jhd25 1:52e0f030d00e 87 tries++;
jhd25 1:52e0f030d00e 88 }
jhd25 1:52e0f030d00e 89 printf("NTP Server Address: %s \r\n",outEndpoint.get_ip_address());
DieterGraef 0:584a18640e84 90 if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
DieterGraef 0:584a18640e84 91 {
DieterGraef 0:584a18640e84 92 m_sock.close();
DieterGraef 0:584a18640e84 93 return NTP_PRTCL;
DieterGraef 0:584a18640e84 94 }
DieterGraef 0:584a18640e84 95
DieterGraef 0:584a18640e84 96 if( pkt.stratum == 0) //Kiss of death message : Not good !
DieterGraef 0:584a18640e84 97 {
DieterGraef 0:584a18640e84 98 m_sock.close();
DieterGraef 0:584a18640e84 99 return NTP_PRTCL;
DieterGraef 0:584a18640e84 100 }
DieterGraef 0:584a18640e84 101
DieterGraef 0:584a18640e84 102 //Correct Endianness
DieterGraef 0:584a18640e84 103 pkt.refTm_s = ntohl( pkt.refTm_s );
DieterGraef 0:584a18640e84 104 pkt.refTm_f = ntohl( pkt.refTm_f );
DieterGraef 0:584a18640e84 105 pkt.origTm_s = ntohl( pkt.origTm_s );
DieterGraef 0:584a18640e84 106 pkt.origTm_f = ntohl( pkt.origTm_f );
DieterGraef 0:584a18640e84 107 pkt.rxTm_s = ntohl( pkt.rxTm_s );
DieterGraef 0:584a18640e84 108 pkt.rxTm_f = ntohl( pkt.rxTm_f );
DieterGraef 0:584a18640e84 109 pkt.txTm_s = ntohl( pkt.txTm_s );
DieterGraef 0:584a18640e84 110 pkt.txTm_f = ntohl( pkt.txTm_f );
DieterGraef 0:584a18640e84 111
DieterGraef 0:584a18640e84 112 //Compute offset, see RFC 4330 p.13
DieterGraef 0:584a18640e84 113 uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
DieterGraef 0:584a18640e84 114 int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
DieterGraef 0:584a18640e84 115 //Set time accordingly
DieterGraef 0:584a18640e84 116 set_time( time(NULL) + offset );
DieterGraef 0:584a18640e84 117
DieterGraef 0:584a18640e84 118
DieterGraef 0:584a18640e84 119 m_sock.close();
DieterGraef 0:584a18640e84 120
DieterGraef 0:584a18640e84 121 return NTP_OK;
DieterGraef 0:584a18640e84 122 }
DieterGraef 0:584a18640e84 123