6 #include <sys/socket.h>
7 #include <netinet/in.h>
18 extern int GetRandInt(int nMax);
21 * NTP uses two fixed point formats. The first (l_fp) is the "long"
22 * format and is 64 bits long with the decimal between bits 31 and 32.
23 * This is used for time stamps in the NTP packet header (in network
24 * byte order) and for internal computations of offsets (in local host
25 * byte order). We use the same structure for both signed and unsigned
26 * values, which is a big hack but saves rewriting all the operators
27 * twice. Just to confuse this, we also sometimes just carry the
28 * fractional part in calculations, in both signed and unsigned forms.
29 * Anyway, an l_fp looks like:
32 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
33 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
35 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
37 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 * REF http://www.eecis.udel.edu/~mills/database/rfc/rfc2030.txt
54 inline void Ntp2Unix(uint32_t &n, time_t &u)
56 // Ntp's time scale starts in 1900, Unix in 1970.
58 u = n - 0x83aa7e80; // 2208988800 1970 - 1900 in seconds
61 inline void ntohl_fp(l_fp *n, l_fp *h)
63 (h)->Ul_i.Xl_ui = ntohl((n)->Ul_i.Xl_ui);
64 (h)->Ul_f.Xl_uf = ntohl((n)->Ul_f.Xl_uf);
68 uint8_t li_vn_mode; /* leap indicator, version and mode */
69 uint8_t stratum; /* peer stratum */
70 uint8_t ppoll; /* peer poll interval */
71 int8_t precision; /* peer clock precision */
72 uint32_t rootdelay; /* distance to primary clock */
73 uint32_t rootdispersion; /* clock dispersion */
74 uint32_t refid; /* reference clock ID */
75 l_fp ref; /* time peer clock was last updated */
76 l_fp org; /* originate time stamp */
77 l_fp rec; /* receive time stamp */
78 l_fp xmt; /* transmit time stamp */
80 uint32_t exten[1]; /* misused */
81 uint8_t mac[5 * sizeof(uint32_t)]; /* mac */
84 int nServersCount = 65;
86 std::string NtpServers[65] = {
116 "ntp1.niiftri.irkutsk.ru",
117 "ntp2.niiftri.irkutsk.ru",
122 "nist1-pa.ustiming.org",
127 "nist1-macon.macon.ga.us",
128 "nist.netservicesgroup.com",
129 "nisttime.carsoncity.k12.mi.us",
130 "nist1-lnk.binary.net",
132 "time-a.timefreq.bldrdoc.gov",
133 "time-b.timefreq.bldrdoc.gov",
134 "time-c.timefreq.bldrdoc.gov",
136 "utcnist.colorado.edu",
137 "utcnist2.colorado.edu",
138 "ntp-nist.ldsbc.net",
139 "nist1-lv.ustiming.org",
141 "nist-time-server.eoni.com",
142 "nist-time-server.eoni.com",
148 "ntp1.meraka.csir.co.za",
152 "ntp1.neology.co.za",
153 "ntp2.neology.co.za",
154 "tick.meraka.csir.co.za",
155 "tock.meraka.csir.co.za",
157 "ntp1.meraka.csir.co.za",
158 "ntp2.meraka.csir.co.za",
164 // ... To be continued
167 bool InitWithRandom(SOCKET &sockfd, socklen_t &servlen, struct sockaddr *pcliaddr)
171 while(nAttempt < 100)
176 int nServerNum = GetRandInt(nServersCount);
178 std::vector<CNetAddr> vIP;
179 bool fRet = LookupHost(NtpServers[nServerNum].c_str(), vIP, 10, true);
183 struct sockaddr_in servaddr;
184 servaddr.sin_family = AF_INET;
185 servaddr.sin_port = htons(123);
188 for(unsigned int i = 0; i < vIP.size(); i++)
190 if ((found = vIP[i].GetInAddr(&servaddr.sin_addr)))
199 sockfd = socket(AF_INET, SOCK_DGRAM, 0);
201 if (sockfd == INVALID_SOCKET)
202 continue; // socket initialization error
204 if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) == -1 )
206 continue; // "connection" error
209 *pcliaddr = *((struct sockaddr *) &servaddr);
210 servlen = sizeof(servaddr);
217 bool InitWithHost(std::string &strHostName, SOCKET &sockfd, socklen_t &servlen, struct sockaddr *pcliaddr)
221 std::vector<CNetAddr> vIP;
222 bool fRet = LookupHost(strHostName.c_str(), vIP, 10, true);
226 struct sockaddr_in servaddr;
227 servaddr.sin_family = AF_INET;
228 servaddr.sin_port = htons(123);
231 for(unsigned int i = 0; i < vIP.size(); i++)
233 if ((found = vIP[i].GetInAddr(&servaddr.sin_addr)))
242 sockfd = socket(AF_INET, SOCK_DGRAM, 0);
244 if (sockfd == INVALID_SOCKET)
245 return false; // socket initialization error
247 if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) == -1 )
249 return false; // "connection" error
253 *pcliaddr = *((struct sockaddr *) &servaddr);
254 servlen = sizeof(servaddr);
260 int64_t DoReq(SOCKET sockfd, socklen_t servlen, struct sockaddr cliaddr)
265 if (ioctlsocket(sockfd, FIONBIO, &nOne) == SOCKET_ERROR)
267 printf("ConnectSocket() : ioctlsocket non-blocking setting failed, error %d\n", WSAGetLastError());
269 if (fcntl(sockfd, F_SETFL, O_NONBLOCK) == SOCKET_ERROR)
271 printf("ConnectSocket() : fcntl non-blocking setting failed, error %d\n", errno);
276 struct pkt *msg = new pkt;
277 struct pkt *prt = new pkt;
284 msg->rootdispersion=0;
286 msg->ref.Ul_i.Xl_i=0;
287 msg->ref.Ul_f.Xl_f=0;
288 msg->org.Ul_i.Xl_i=0;
289 msg->org.Ul_f.Xl_f=0;
290 msg->rec.Ul_i.Xl_i=0;
291 msg->rec.Ul_f.Xl_f=0;
292 msg->xmt.Ul_i.Xl_i=0;
293 msg->xmt.Ul_f.Xl_f=0;
296 int retcode = sendto(sockfd, (char *) msg, len, 0, &cliaddr, servlen);
298 printf("sendto() failed: %d", retcode);
305 while(retcode <= 0) {
307 retcode = recvfrom(sockfd, (char *) msg, len, 0, NULL, NULL);
310 printf("recvfrom() timeout");
317 ntohl_fp(&msg->rec, &prt->rec);
318 ntohl_fp(&msg->xmt, &prt->xmt);
320 time_t seconds_receive;
321 time_t seconds_transmit;
323 Ntp2Unix(prt->rec.Ul_i.Xl_ui, seconds_receive);
324 Ntp2Unix(prt->xmt.Ul_i.Xl_ui, seconds_transmit);
329 return (seconds_receive + seconds_transmit) / 2;
334 struct sockaddr cliaddr;
339 if (!InitWithRandom(sockfd, servlen, &cliaddr))
342 int64_t nTime = DoReq(sockfd, servlen, cliaddr);
349 int64_t NtpGetTime(std::string &strHostName)
351 struct sockaddr cliaddr;
356 if (!InitWithHost(strHostName, sockfd, servlen, &cliaddr))
359 int64_t nTime = DoReq(sockfd, servlen, cliaddr);