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NTPClient.cpp@0:9fa20c138e48, 2012-05-31 (annotated)

Committer:: donatien
Date:: Thu May 31 16:02:20 2012 +0000
Revision:: 0:9fa20c138e48

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User	Revision	Line number	New contents of line
donatien	0:9fa20c138e48	1	/* NTPClient.cpp */
donatien	0:9fa20c138e48	2	/*
donatien	0:9fa20c138e48	3	Copyright (C) 2012 ARM Limited.
donatien	0:9fa20c138e48	4
donatien	0:9fa20c138e48	5	Permission is hereby granted, free of charge, to any person obtaining a copy of
donatien	0:9fa20c138e48	6	this software and associated documentation files (the "Software"), to deal in
donatien	0:9fa20c138e48	7	the Software without restriction, including without limitation the rights to
donatien	0:9fa20c138e48	8	use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
donatien	0:9fa20c138e48	9	of the Software, and to permit persons to whom the Software is furnished to do
donatien	0:9fa20c138e48	10	so, subject to the following conditions:
donatien	0:9fa20c138e48	11
donatien	0:9fa20c138e48	12	The above copyright notice and this permission notice shall be included in all
donatien	0:9fa20c138e48	13	copies or substantial portions of the Software.
donatien	0:9fa20c138e48	14
donatien	0:9fa20c138e48	15	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
donatien	0:9fa20c138e48	16	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
donatien	0:9fa20c138e48	17	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
donatien	0:9fa20c138e48	18	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
donatien	0:9fa20c138e48	19	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
donatien	0:9fa20c138e48	20	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
donatien	0:9fa20c138e48	21	SOFTWARE.
donatien	0:9fa20c138e48	22	*/
donatien	0:9fa20c138e48	23
donatien	0:9fa20c138e48	24	#define __DEBUG__ 4 //Maximum verbosity
donatien	0:9fa20c138e48	25	#ifndef __MODULE__
donatien	0:9fa20c138e48	26	#define __MODULE__ "NTPClient.cpp"
donatien	0:9fa20c138e48	27	#endif
donatien	0:9fa20c138e48	28
donatien	0:9fa20c138e48	29	#include "core/fwk.h"
donatien	0:9fa20c138e48	30
donatien	0:9fa20c138e48	31	#include "NTPClient.h"
donatien	0:9fa20c138e48	32
donatien	0:9fa20c138e48	33	#include "mbed.h" //time() and set_time()
donatien	0:9fa20c138e48	34
donatien	0:9fa20c138e48	35	#define NTP_PORT 123
donatien	0:9fa20c138e48	36	#define NTP_CLIENT_PORT 0 //Random port
donatien	0:9fa20c138e48	37	#define NTP_REQUEST_TIMEOUT 15000
donatien	0:9fa20c138e48	38	#define NTP_TIMESTAMP_DELTA 2208988800ull //Diff btw a UNIX timestamp (Starting Jan, 1st 1970) and a NTP timestamp (Starting Jan, 1st 1900)
donatien	0:9fa20c138e48	39
donatien	0:9fa20c138e48	40	NTPClient::NTPClient()
donatien	0:9fa20c138e48	41	{
donatien	0:9fa20c138e48	42
donatien	0:9fa20c138e48	43
donatien	0:9fa20c138e48	44	}
donatien	0:9fa20c138e48	45
donatien	0:9fa20c138e48	46	int NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout)
donatien	0:9fa20c138e48	47	{
donatien	0:9fa20c138e48	48	struct sockaddr_in serverAddr;
donatien	0:9fa20c138e48	49
donatien	0:9fa20c138e48	50	std::memset(&serverAddr, 0, sizeof(struct sockaddr_in));
donatien	0:9fa20c138e48	51
donatien	0:9fa20c138e48	52	#if __DEBUG__ >= 3
donatien	0:9fa20c138e48	53	time_t ctTime;
donatien	0:9fa20c138e48	54	ctTime = time(NULL);
donatien	0:9fa20c138e48	55	INFO("Time is set to (UTC): %s", ctime(&ctTime));
donatien	0:9fa20c138e48	56	#endif
donatien	0:9fa20c138e48	57
donatien	0:9fa20c138e48	58	//Resolve DNS if needed
donatien	0:9fa20c138e48	59	if(serverAddr.sin_addr.s_addr == 0)
donatien	0:9fa20c138e48	60	{
donatien	0:9fa20c138e48	61	DBG("Resolving DNS address or populate hard-coded IP address");
donatien	0:9fa20c138e48	62	struct hostent *server = socket::gethostbyname(host);
donatien	0:9fa20c138e48	63	if(server == NULL)
donatien	0:9fa20c138e48	64	{
donatien	0:9fa20c138e48	65	return NET_NOTFOUND; //Fail
donatien	0:9fa20c138e48	66	}
donatien	0:9fa20c138e48	67	memcpy((char)&serverAddr.sin_addr.s_addr, (char)server->h_addr_list[0], server->h_length);
donatien	0:9fa20c138e48	68	}
donatien	0:9fa20c138e48	69
donatien	0:9fa20c138e48	70	serverAddr.sin_family = AF_INET;
donatien	0:9fa20c138e48	71	serverAddr.sin_port = htons(port);
donatien	0:9fa20c138e48	72
donatien	0:9fa20c138e48	73	//Now create & bind socket
donatien	0:9fa20c138e48	74	DBG("Creating socket");
donatien	0:9fa20c138e48	75	int sock = socket::socket(AF_INET, SOCK_DGRAM, 0); //UDP socket
donatien	0:9fa20c138e48	76	if (sock < 0)
donatien	0:9fa20c138e48	77	{
donatien	0:9fa20c138e48	78	ERR("Could not create socket");
donatien	0:9fa20c138e48	79	return NET_OOM;
donatien	0:9fa20c138e48	80	}
donatien	0:9fa20c138e48	81	DBG("Handle is %d",sock);
donatien	0:9fa20c138e48	82
donatien	0:9fa20c138e48	83	//Create local address
donatien	0:9fa20c138e48	84	struct sockaddr_in localhostAddr;
donatien	0:9fa20c138e48	85
donatien	0:9fa20c138e48	86	std::memset(&localhostAddr, 0, sizeof(struct sockaddr_in));
donatien	0:9fa20c138e48	87
donatien	0:9fa20c138e48	88	localhostAddr.sin_family = AF_INET;
donatien	0:9fa20c138e48	89	localhostAddr.sin_port = htons(NTP_CLIENT_PORT); //Random port
donatien	0:9fa20c138e48	90	localhostAddr.sin_addr.s_addr = htonl(INADDR_ANY); //Any local address
donatien	0:9fa20c138e48	91
donatien	0:9fa20c138e48	92	if ( socket::bind( sock, (struct sockaddr*)&localhostAddr, sizeof(localhostAddr)) < 0 ) //Listen on local port
donatien	0:9fa20c138e48	93	{
donatien	0:9fa20c138e48	94	ERR("Could not bind socket");
donatien	0:9fa20c138e48	95	socket::close(sock);
donatien	0:9fa20c138e48	96	return NET_OOM;
donatien	0:9fa20c138e48	97	}
donatien	0:9fa20c138e48	98
donatien	0:9fa20c138e48	99	struct NTPPacket pkt;
donatien	0:9fa20c138e48	100
donatien	0:9fa20c138e48	101	//Now ping the server and wait for response
donatien	0:9fa20c138e48	102	DBG("Ping");
donatien	0:9fa20c138e48	103	//Prepare NTP Packet:
donatien	0:9fa20c138e48	104	pkt.li = 0; //Leap Indicator : No warning
donatien	0:9fa20c138e48	105	pkt.vn = 4; //Version Number : 4
donatien	0:9fa20c138e48	106	pkt.mode = 3; //Client mode
donatien	0:9fa20c138e48	107	pkt.stratum = 0; //Not relevant here
donatien	0:9fa20c138e48	108	pkt.poll = 0; //Not significant as well
donatien	0:9fa20c138e48	109	pkt.precision = 0; //Neither this one is
donatien	0:9fa20c138e48	110
donatien	0:9fa20c138e48	111	pkt.rootDelay = 0; //Or this one
donatien	0:9fa20c138e48	112	pkt.rootDispersion = 0; //Or that one
donatien	0:9fa20c138e48	113	pkt.refId = 0; //...
donatien	0:9fa20c138e48	114
donatien	0:9fa20c138e48	115	pkt.refTm_s = 0;
donatien	0:9fa20c138e48	116	pkt.origTm_s = 0;
donatien	0:9fa20c138e48	117	pkt.rxTm_s = 0;
donatien	0:9fa20c138e48	118	pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE
donatien	0:9fa20c138e48	119
donatien	0:9fa20c138e48	120	pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0;
donatien	0:9fa20c138e48	121
donatien	0:9fa20c138e48	122	//Set timeout, non-blocking and wait using select
donatien	0:9fa20c138e48	123	if( socket::sendto( sock, (void)&pkt, sizeof(NTPPacket), 0, (struct sockaddr)&serverAddr, sizeof(serverAddr) ) < 0 )
donatien	0:9fa20c138e48	124	{
donatien	0:9fa20c138e48	125	ERR("Could not send packet");
donatien	0:9fa20c138e48	126	socket::close(sock);
donatien	0:9fa20c138e48	127	return NET_CONN;
donatien	0:9fa20c138e48	128	}
donatien	0:9fa20c138e48	129
donatien	0:9fa20c138e48	130	//Wait for socket to be readable
donatien	0:9fa20c138e48	131	//Creating FS set
donatien	0:9fa20c138e48	132	fd_set socksSet;
donatien	0:9fa20c138e48	133	FD_ZERO(&socksSet);
donatien	0:9fa20c138e48	134	FD_SET(sock, &socksSet);
donatien	0:9fa20c138e48	135	struct timeval t_val;
donatien	0:9fa20c138e48	136	t_val.tv_sec = timeout / 1000;
donatien	0:9fa20c138e48	137	t_val.tv_usec = (timeout - (t_val.tv_sec * 1000)) * 1000;
donatien	0:9fa20c138e48	138	int ret = socket::select(FD_SETSIZE, &socksSet, NULL, NULL, &t_val);
donatien	0:9fa20c138e48	139	if(ret <= 0 \|\| !FD_ISSET(sock, &socksSet))
donatien	0:9fa20c138e48	140	{
donatien	0:9fa20c138e48	141	ERR("Timeout while waiting for answer");
donatien	0:9fa20c138e48	142	socket::close(sock);
donatien	0:9fa20c138e48	143	return NET_TIMEOUT; //Timeout
donatien	0:9fa20c138e48	144	}
donatien	0:9fa20c138e48	145
donatien	0:9fa20c138e48	146	//Read response
donatien	0:9fa20c138e48	147	DBG("Pong");
donatien	0:9fa20c138e48	148	struct sockaddr_in respAddr;
donatien	0:9fa20c138e48	149	socklen_t respAddrLen = sizeof(respAddr);
donatien	0:9fa20c138e48	150	do
donatien	0:9fa20c138e48	151	{
donatien	0:9fa20c138e48	152	ret = socket::recvfrom( sock, (void)&pkt, sizeof(NTPPacket), 0, (struct sockaddr)&respAddr, &respAddrLen);
donatien	0:9fa20c138e48	153	if(ret < 0)
donatien	0:9fa20c138e48	154	{
donatien	0:9fa20c138e48	155	ERR("Could not receive packet");
donatien	0:9fa20c138e48	156	socket::close(sock);
donatien	0:9fa20c138e48	157	return NET_CONN;
donatien	0:9fa20c138e48	158	}
donatien	0:9fa20c138e48	159	} while( respAddr.sin_addr.s_addr != serverAddr.sin_addr.s_addr);
donatien	0:9fa20c138e48	160
donatien	0:9fa20c138e48	161	if(ret < sizeof(NTPPacket)) //TODO: Accept chunks
donatien	0:9fa20c138e48	162	{
donatien	0:9fa20c138e48	163	ERR("Receive packet size does not match");
donatien	0:9fa20c138e48	164	socket::close(sock);
donatien	0:9fa20c138e48	165	return NET_PROTOCOL;
donatien	0:9fa20c138e48	166	}
donatien	0:9fa20c138e48	167
donatien	0:9fa20c138e48	168	if( pkt.stratum == 0) //Kiss of death message : Not good !
donatien	0:9fa20c138e48	169	{
donatien	0:9fa20c138e48	170	ERR("Kissed to death!");
donatien	0:9fa20c138e48	171	socket::close(sock);
donatien	0:9fa20c138e48	172	return NTP_PORT;
donatien	0:9fa20c138e48	173	}
donatien	0:9fa20c138e48	174
donatien	0:9fa20c138e48	175	//Correct Endianness
donatien	0:9fa20c138e48	176	pkt.refTm_s = ntohl( pkt.refTm_s );
donatien	0:9fa20c138e48	177	pkt.refTm_f = ntohl( pkt.refTm_f );
donatien	0:9fa20c138e48	178	pkt.origTm_s = ntohl( pkt.origTm_s );
donatien	0:9fa20c138e48	179	pkt.origTm_f = ntohl( pkt.origTm_f );
donatien	0:9fa20c138e48	180	pkt.rxTm_s = ntohl( pkt.rxTm_s );
donatien	0:9fa20c138e48	181	pkt.rxTm_f = ntohl( pkt.rxTm_f );
donatien	0:9fa20c138e48	182	pkt.txTm_s = ntohl( pkt.txTm_s );
donatien	0:9fa20c138e48	183	pkt.txTm_f = ntohl( pkt.txTm_f );
donatien	0:9fa20c138e48	184
donatien	0:9fa20c138e48	185	//Compute offset, see RFC 4330 p.13
donatien	0:9fa20c138e48	186	uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL));
donatien	0:9fa20c138e48	187	int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow
donatien	0:9fa20c138e48	188	DBG("Sent @%ul", pkt.txTm_s);
donatien	0:9fa20c138e48	189	DBG("Offset: %ul", offset);
donatien	0:9fa20c138e48	190	//Set time accordingly
donatien	0:9fa20c138e48	191	set_time( time(NULL) + offset );
donatien	0:9fa20c138e48	192
donatien	0:9fa20c138e48	193	#if __DEBUG__ >= 3
donatien	0:9fa20c138e48	194	ctTime = time(NULL);
donatien	0:9fa20c138e48	195	INFO("Time is now (UTC): %s", ctime(&ctTime));
donatien	0:9fa20c138e48	196	#endif
donatien	0:9fa20c138e48	197
donatien	0:9fa20c138e48	198	socket::close(sock);
donatien	0:9fa20c138e48	199
donatien	0:9fa20c138e48	200	return OK;
donatien	0:9fa20c138e48	201	}
donatien	0:9fa20c138e48	202

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Type:	Program
Created:	31 May 2012
Imports:	6
Forks:	0
Commits:	1
Dependents:	0
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NTPClient.cpp@0:9fa20c138e48, 2012-05-31 (annotated)

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