services/ntp_client.h

   1 #ifndef _NTP_CLIENT_H_
   2 #define _NTP_CLIENT_H_
   3
   4 #include "resources/net/client_socket.h"
   5 #include "resources/net/udp.h"
   6
   7 #include "time_source.h"
   8
   9 namespace services {
  10         class ntp_client : time_source {
  11         private:
  12                 typedef int u64[2];
  13                 struct ntp_packet {
  14                         u8 flags;
  15                         u8 stratum;
  16                         u8 poll_int;
  17                         u8 precision;
  18                         u32 root_delay;
  19                         u32 root_dispersion;
  20                         u32 ref_clock_id;
  21                         u64 ref_clock_update;
  22                         u64 orig_time_stamp;
  23                         u64 rec_time_stamp;
  24                         u64 trans_time_stamp;
  25                 };
  26
  27                 enum ntp_flags {
  28                         ntp_cli = 3,
  29                         ntp_srv = 4,
  30                         ntp_ver4 = 0x20,
  31                         ntp_alarm = 0xc0
  32                 };
  33
  34                 enum {
  35                         ntp_port = 123
  36                 };
  37
  38                 p<net::client_socket> client;
  39
  40                 p<ntp_packet> pkg;
  41         public:
  42                 ~ntp_client() {
  43                         if (client.valid())
  44                                 client->close();
  45                 }
  46
  47                 void set(p<net::udp> u) {
  48                         client = u->create_client();
  49                         client->connect(net::ipv4_addr::from_le(213 << 24 | 134 << 16 | 184 << 8 | 12), ntp_port);
  50
  51                         pkg = new ntp_packet;
  52                 }
  53
  54                 time_source::time_stamp get_timestamp() {
  55                         pkg->flags = ntp_cli | ntp_ver4 | ntp_alarm;
  56                         pkg->poll_int = 6;
  57                         pkg->ref_clock_id = to_be32(0x494e4954);
  58
  59                         client->write(buffer::to_mem(pkg));
  60
  61                         buffer buf = buffer::to_mem(pkg);
  62                         client->read(buf);
  63
  64                         time_source::time_stamp timestamp = from_be32(buf.cast<ntp_packet>()->rec_time_stamp[0]);
  65
  66                         /* NTP uses Jan 01 1900 as a base, we need Jan 01 1970 */
  67                         timestamp -= 2208988800;
  68
  69                         return timestamp;
  70                 }
  71         };
  72 }
  73
  74 #endif