NTPClient.h

00001 /*
00002 Copyright (c) 2011, Senio Networks, Inc.
00003 
00004 Permission is hereby granted, free of charge, to any person obtaining a copy
00005 of this software and associated documentation files (the "Software"), to deal
00006 in the Software without restriction, including without limitation the rights
00007 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008 copies of the Software, and to permit persons to whom the Software is
00009 furnished to do so, subject to the following conditions:
00010 
00011 The above copyright notice and this permission notice shall be included in
00012 all copies or substantial portions of the Software.
00013 
00014 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020 THE SOFTWARE.
00021 */
00022 
00023 #include "SimpleSocket.h"
00024 #include "Utils.h"
00025 
00026 /**
00027  * NTP Client interface to adjust RTC
00028  */
00029 class NTPClient {
00030 public:
00031     /**
00032      * creates an NTPClient object
00033      *
00034      * @param server NTP server host name
00035      * @param timeout max wait time for connection
00036      */
00037     NTPClient(char *server = "pool.ntp.org", float timeout = 3.0) : timeout(timeout) {
00038         strncpy(this->server, server, sizeof(this->server));
00039     }
00040 
00041     /**
00042      * creates an NTPClient object from a config file
00043      *
00044      * @param filename name for the configuration file containing server host name and timeout
00045      * @param verbose if true display debug info
00046      */
00047     static NTPClient create(char *filename, bool verbose = false) {
00048         char server[32] = "pool.ntp.org";
00049         float timeout = 3.0;
00050 
00051         if (filename) {
00052             char path[32];
00053             LocalFileSystem local("local");
00054             sprintf(path, "/local/%s", filename);
00055             if (FILE *fp = fopen(path, "r")) {
00056                 Utils::fgetValues(fp, "ntp-server:%s", server);
00057                 Utils::fgetValues(fp, "ntp-timeout:%f", &timeout);
00058                 fclose(fp);
00059                 if (verbose) {
00060                     printf("ntp-server:%s\n", server);
00061                     printf("ntp-timeout:%2.1f\n", timeout);
00062                 }
00063             }
00064         }
00065 
00066         return NTPClient(server, timeout);
00067     }
00068 
00069     /**
00070      * adjusts RTC
00071      *
00072      * @returns true if succeeded
00073      */
00074     bool setTime() {
00075         Timer timer;
00076         timer.start();
00077         while (timer.read() < timeout) {
00078             DatagramSocket datagram;
00079             char buf[48] = {0x23}; // 00100011 LI(0), Version(4), Mode(3: Client)
00080             datagram.write(buf, sizeof(buf));
00081             datagram.send(server, 123);
00082 
00083             if (datagram.receive(0, timeout) > 0) {
00084                 if (datagram.read(buf, sizeof(buf))) {
00085                     unsigned long seconds = 0;
00086                     for (int i = 40; i <= 43; i++)
00087                         seconds = (seconds << 8) | buf[i];
00088                     set_time(time_t(seconds - 2208988800ULL));
00089                     return true;
00090                 }
00091             }
00092         }
00093 
00094         return false;
00095     }
00096 
00097 private:
00098     char server[32];
00099     float timeout;
00100 };