1 /* $NetBSD: refclock_local.c,v 1.5 2016/01/08 21:35:39 christos 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 * None currently supported. 61 */ 62 /* 63 * Local interface definitions 64 */ 65 #define PRECISION (-7) /* about 10 ms precision */ 66 #define DESCRIPTION "Undisciplined local clock" /* WRU */ 67 #define STRATUM 5 /* default stratum */ 68 #define DISPERSION .01 /* default dispersion (10 ms) */ 69 70 /* 71 * Imported from the timer module 72 */ 73 extern u_long current_time; 74 75 /* 76 * Imported from ntp_proto 77 */ 78 extern s_char sys_precision; 79 80 /* 81 * Function prototypes 82 */ 83 static int local_start (int, struct peer *); 84 static void local_poll (int, struct peer *); 85 86 /* 87 * Local variables 88 */ 89 static u_long poll_time; /* last time polled */ 90 91 /* 92 * Transfer vector 93 */ 94 struct refclock refclock_local = { 95 local_start, /* start up driver */ 96 noentry, /* shut down driver (not used) */ 97 local_poll, /* transmit poll message */ 98 noentry, /* not used (old lcl_control) */ 99 noentry, /* initialize driver (not used) */ 100 noentry, /* not used (old lcl_buginfo) */ 101 NOFLAGS /* not used */ 102 }; 103 104 105 /* 106 * local_start - start up the clock 107 */ 108 static int 109 local_start( 110 int unit, 111 struct peer *peer 112 ) 113 { 114 struct refclockproc *pp; 115 116 pp = peer->procptr; 117 118 /* 119 * Initialize miscellaneous variables 120 */ 121 peer->precision = sys_precision; 122 pp->leap = LEAP_NOTINSYNC; 123 peer->stratum = STRATUM; 124 pp->stratum = STRATUM; 125 pp->clockdesc = DESCRIPTION; 126 memcpy(&pp->refid, "LOCL", 4); 127 poll_time = current_time; 128 return (1); 129 } 130 131 132 /* 133 * local_poll - called by the transmit procedure 134 * 135 * LOCKCLOCK: If the kernel supports the nanokernel or microkernel 136 * system calls, the leap bits are extracted from the kernel. If there 137 * is a kernel error or the kernel leap bits are set to 11, the NTP leap 138 * bits are set to 11 and the stratum is set to infinity. Otherwise, the 139 * NTP leap bits are set to the kernel leap bits and the stratum is set 140 * as fudged. This behavior does not faithfully follow the 141 * specification, but is probably more appropriate in a multiple-server 142 * national laboratory network. 143 */ 144 static void 145 local_poll( 146 int unit, 147 struct peer *peer 148 ) 149 { 150 #if defined(KERNEL_PLL) && defined(LOCKCLOCK) 151 struct timex ntv; 152 #endif /* KERNEL_PLL LOCKCLOCK */ 153 struct refclockproc *pp; 154 155 /* 156 * Do no evil unless the house is dark or lit with our own lamp. 157 */ 158 if (!(sys_peer == NULL || sys_peer == peer)) 159 return; 160 161 #if defined(VMS) && defined(VMS_LOCALUNIT) 162 if (unit == VMS_LOCALUNIT) { 163 extern void vms_local_poll(struct peer *); 164 165 vms_local_poll(peer); 166 return; 167 } 168 #endif /* VMS && VMS_LOCALUNIT */ 169 170 pp = peer->procptr; 171 pp->polls++; 172 173 /* 174 * Ramble through the usual filtering and grooming code, which 175 * is essentially a no-op and included mostly for pretty 176 * billboards. 177 */ 178 poll_time = current_time; 179 refclock_process_offset(pp, pp->lastrec, pp->lastrec, 0); 180 181 /* 182 * If another process is disciplining the system clock, we set 183 * the leap bits and quality indicators from the kernel. 184 */ 185 #if defined(KERNEL_PLL) && defined(LOCKCLOCK) 186 memset(&ntv, 0, sizeof ntv); 187 switch (ntp_adjtime(&ntv)) { 188 case TIME_OK: 189 pp->leap = LEAP_NOWARNING; 190 peer->stratum = pp->stratum; 191 break; 192 193 case TIME_INS: 194 pp->leap = LEAP_ADDSECOND; 195 peer->stratum = pp->stratum; 196 break; 197 198 case TIME_DEL: 199 pp->leap = LEAP_DELSECOND; 200 peer->stratum = pp->stratum; 201 break; 202 203 default: 204 pp->leap = LEAP_NOTINSYNC; 205 peer->stratum = STRATUM_UNSPEC; 206 } 207 pp->disp = 0; 208 pp->jitter = 0; 209 #else /* KERNEL_PLL LOCKCLOCK */ 210 pp->leap = LEAP_NOWARNING; 211 pp->disp = DISPERSION; 212 pp->jitter = 0; 213 #endif /* KERNEL_PLL LOCKCLOCK */ 214 pp->lastref = pp->lastrec; 215 refclock_receive(peer); 216 } 217 #else 218 int refclock_local_bs; 219 #endif /* REFCLOCK */ 220