refclock_local.c revision 1.2.4.2
1 /* $NetBSD: refclock_local.c,v 1.2.4.2 2015/01/07 10:10:15 msaitoh Exp $ */ 2 3 4 /* 5 * refclock_local - local pseudo-clock driver 6 * 7 * wjm 17-aug-1995: add a hook for special treatment of VMS_LOCALUNIT 8 */ 9 #ifdef HAVE_CONFIG_H 10 #include <config.h> 11 #endif 12 13 #ifdef REFCLOCK 14 15 #include "ntpd.h" 16 #include "ntp_refclock.h" 17 #include "ntp_stdlib.h" 18 19 #include <stdio.h> 20 #include <ctype.h> 21 22 #ifdef KERNEL_PLL 23 #include "ntp_syscall.h" 24 #endif 25 26 /* 27 * This is a hack to allow a machine to use its own system clock as a 28 * reference clock, i.e., to free-run using no outside clock discipline 29 * source. Note that the clock selection algorithm will not select this 30 * driver unless all other sources of synchronization have been lost. 31 * This is useful if you want to use NTP in an isolated environment 32 * with no radio clock or NIST modem available. Pick a machine that you 33 * figure has a good clock oscillator and configure it with this 34 * driver. Set the clock using the best means available, like 35 * eyeball-and-wristwatch. Then, point all the other machines at this 36 * one or use broadcast (not multicast) mode to distribute time. 37 * 38 * Another application for this driver is if you want to use a 39 * particular server's clock as the clock of last resort when all other 40 * normal synchronization sources have gone away. This is especially 41 * useful if that server has an ovenized oscillator. However, the 42 * preferred was to do this is using orphan mode. See the documentation. 43 * 44 * A third application for this driver is when an external discipline 45 * source is available, such as the NIST "lockclock" program, which 46 * synchronizes the local clock via a telephone modem and the NIST 47 * Automated Computer Time Service (ACTS), or the Digital Time 48 * Synchronization Service (DTSS), which runs on DCE machines. In this 49 * case the stratum should be set at zero, indicating a bona fide 50 * stratum-1 source. Exercise some caution with this, since there is no 51 * easy way to telegraph via NTP that something might be wrong in the 52 * discipline source itself. In the case of DTSS, the local clock can 53 * have a rather large jitter, depending on the interval between 54 * corrections and the intrinsic frequency error of the clock 55 * oscillator. In extreme cases, this can cause clients to exceed the 56 * 128-ms slew window and drop off the NTP subnet. 57 * 58 * Fudge Factors 59 * 60 * If fudge flag1 is lit, the leap second bit is set in the peer 61 * status word. It should be set early in the day of a leap second 62 * event and set dark on the day after the event. 63 * 64 * Note the fudge time1 and time2 have been deprecated. The fudge time1 65 * was intended to apply a bias offset. This can be done using the Unix 66 * date command. The fudge time2 was intended to apply a bias frequency. 67 * This can be done using the frequency file and/or the freq 68 * configuration command. 69 */ 70 /* 71 * Local interface definitions 72 */ 73 #define PRECISION (-7) /* about 10 ms precision */ 74 #define DESCRIPTION "Undisciplined local clock" /* WRU */ 75 #define STRATUM 5 /* default stratum */ 76 #define DISPERSION .01 /* default dispersion (10 ms) */ 77 78 /* 79 * Imported from the timer module 80 */ 81 extern u_long current_time; 82 83 /* 84 * Imported from ntp_proto 85 */ 86 extern s_char sys_precision; 87 88 /* 89 * Function prototypes 90 */ 91 static int local_start (int, struct peer *); 92 static void local_poll (int, struct peer *); 93 94 /* 95 * Local variables 96 */ 97 static u_long poll_time; /* last time polled */ 98 99 /* 100 * Transfer vector 101 */ 102 struct refclock refclock_local = { 103 local_start, /* start up driver */ 104 noentry, /* shut down driver (not used) */ 105 local_poll, /* transmit poll message */ 106 noentry, /* not used (old lcl_control) */ 107 noentry, /* initialize driver (not used) */ 108 noentry, /* not used (old lcl_buginfo) */ 109 NOFLAGS /* not used */ 110 }; 111 112 113 /* 114 * local_start - start up the clock 115 */ 116 static int 117 local_start( 118 int unit, 119 struct peer *peer 120 ) 121 { 122 struct refclockproc *pp; 123 124 pp = peer->procptr; 125 126 /* 127 * Initialize miscellaneous variables 128 */ 129 peer->precision = sys_precision; 130 pp->leap = LEAP_NOTINSYNC; 131 peer->stratum = STRATUM; 132 pp->stratum = STRATUM; 133 pp->clockdesc = DESCRIPTION; 134 memcpy(&pp->refid, "LOCL", 4); 135 poll_time = current_time; 136 return (1); 137 } 138 139 140 /* 141 * local_poll - called by the transmit procedure 142 * 143 * LOCKCLOCK: If the kernel supports the nanokernel or microkernel 144 * system calls, the leap bits are extracted from the kernel. If there 145 * is a kernel error or the kernel leap bits are set to 11, the NTP leap 146 * bits are set to 11 and the stratum is set to infinity. Otherwise, the 147 * NTP leap bits are set to the kernel leap bits and the stratum is set 148 * as fudged. This behavior does not faithfully follow the 149 * specification, but is probably more appropriate in a multiple-server 150 * national laboratory network. 151 */ 152 static void 153 local_poll( 154 int unit, 155 struct peer *peer 156 ) 157 { 158 #if defined(KERNEL_PLL) && defined(LOCKCLOCK) 159 struct timex ntv; 160 #endif /* KERNEL_PLL LOCKCLOCK */ 161 struct refclockproc *pp; 162 163 /* 164 * Do no evil unless the house is dark or lit with our own lamp. 165 */ 166 if (!(sys_peer == NULL || sys_peer == peer)) 167 return; 168 169 #if defined(VMS) && defined(VMS_LOCALUNIT) 170 if (unit == VMS_LOCALUNIT) { 171 extern void vms_local_poll(struct peer *); 172 173 vms_local_poll(peer); 174 return; 175 } 176 #endif /* VMS && VMS_LOCALUNIT */ 177 178 pp = peer->procptr; 179 pp->polls++; 180 181 /* 182 * Ramble through the usual filtering and grooming code, which 183 * is essentially a no-op and included mostly for pretty 184 * billboards. We allow a one-time time adjustment using fudge 185 * time1 (s) and a continuous frequency adjustment using fudge 186 * time 2 (ppm). 187 */ 188 poll_time = current_time; 189 refclock_process_offset(pp, pp->lastrec, pp->lastrec, 0); 190 191 /* 192 * If another process is disciplining the system clock, we set 193 * the leap bits and quality indicators from the kernel. 194 */ 195 #if defined(KERNEL_PLL) && defined(LOCKCLOCK) 196 memset(&ntv, 0, sizeof ntv); 197 switch (ntp_adjtime(&ntv)) { 198 case TIME_OK: 199 pp->leap = LEAP_NOWARNING; 200 peer->stratum = pp->stratum; 201 break; 202 203 case TIME_INS: 204 pp->leap = LEAP_ADDSECOND; 205 peer->stratum = pp->stratum; 206 break; 207 208 case TIME_DEL: 209 pp->leap = LEAP_DELSECOND; 210 peer->stratum = pp->stratum; 211 break; 212 213 default: 214 pp->leap = LEAP_NOTINSYNC; 215 peer->stratum = STRATUM_UNSPEC; 216 } 217 pp->disp = 0; 218 pp->jitter = 0; 219 #else /* KERNEL_PLL LOCKCLOCK */ 220 if (pp->sloppyclockflag & CLK_FLAG1) 221 pp->leap = LEAP_ADDSECOND; 222 else 223 pp->leap = LEAP_NOWARNING; 224 pp->disp = DISPERSION; 225 pp->jitter = 0; 226 #endif /* KERNEL_PLL LOCKCLOCK */ 227 pp->lastref = pp->lastrec; 228 refclock_receive(peer); 229 } 230 #else 231 int refclock_local_bs; 232 #endif /* REFCLOCK */ 233
Indexes created Fri May 01 00:23:41 UTC 2026