Diff: NTPClient.cpp

Revision:

0:2f003df80c99

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NTPClient.cpp	Wed Aug 22 09:40:23 2018 +0000
@@ -0,0 +1,184 @@
+/* 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 0
+//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 "NTPClient.h"
+
+#include "UDPSocket.h"
+#include "def.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(NetworkInterface *_stack) {
+	stack = _stack;
+}
+
+NTPResult NTPClient::start(const char* _host,uint16_t _delay,uint16_t _port){
+	strcpy(host,_host);
+	port = _port;
+	delay = _delay;
+	NTPThread.start(callback(this,&NTPClient::keepTime));
+	return NTP_OK;
+}
+
+void NTPClient::keepTime(){
+	while(1)
+	{
+		setTime(host,port);
+		Thread::wait(delay*1000);
+	}
+}
+
+
+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.open(stack);
+
+	m_sock.bind(0); //Bind to a random port
+
+	m_sock.set_blocking(false); //Set not blocking
+	m_sock.set_timeout(timeout); //Set not blocking timeout
+
+	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;
+
+	SocketAddress outEndpoint;
+	 if( stack->gethostbyname(host, &outEndpoint)!=0)
+	 {
+	 m_sock.close();
+	 return NTP_DNS;
+	 }
+	 	outEndpoint.set_port(port);
+
+
+	//Set timeout, non-blocking and wait using select
+	int ret = m_sock.sendto(outEndpoint, (char*) &pkt, sizeof(NTPPacket));
+	if (ret < 0) {
+		ERR("Could not send packet");
+		m_sock.close();
+		return NTP_CONN;
+	}
+
+	//Read response
+	SocketAddress inEndpoint;
+
+	DBG("Pong");
+	do {
+		ret = m_sock.recvfrom(&inEndpoint, (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;
+		}
+	} while (strcmp(outEndpoint.get_ip_address(), inEndpoint.get_ip_address())
+			!= 0);
+
+	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
+	time_t seconds = time(NULL);
+
+	printf("Time  = %s\r\n", ctime(&seconds));
+
+	m_sock.close();
+
+	return NTP_OK;
+}
+