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| Current File : //usr/src/contrib/ntp/ntpd/refclock_nmea.c |
/*
* refclock_nmea.c - clock driver for an NMEA GPS CLOCK
* Michael Petry Jun 20, 1994
* based on refclock_heathn.c
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#if defined(REFCLOCK) && defined(CLOCK_NMEA)
#include <stdio.h>
#include <ctype.h>
#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_unixtime.h"
#include "ntp_refclock.h"
#include "ntp_stdlib.h"
#ifdef HAVE_PPSAPI
# include "ppsapi_timepps.h"
#endif /* HAVE_PPSAPI */
#ifdef SYS_WINNT
extern int async_write(int, const void *, unsigned int);
#undef write
#define write(fd, data, octets) async_write(fd, data, octets)
#endif
/*
* This driver supports the NMEA GPS Receiver with
*
* Protype was refclock_trak.c, Thanks a lot.
*
* The receiver used spits out the NMEA sentences for boat navigation.
* And you thought it was an information superhighway. Try a raging river
* filled with rapids and whirlpools that rip away your data and warp time.
*
* If HAVE_PPSAPI is defined code to use the PPSAPI will be compiled in.
* On startup if initialization of the PPSAPI fails, it will fall back
* to the "normal" timestamps.
*
* The PPSAPI part of the driver understands fudge flag2 and flag3. If
* flag2 is set, it will use the clear edge of the pulse. If flag3 is
* set, kernel hardpps is enabled.
*
* GPS sentences other than RMC (the default) may be enabled by setting
* the relevent bits of 'mode' in the server configuration line
* server 127.127.20.x mode X
*
* bit 0 - enables RMC (1)
* bit 1 - enables GGA (2)
* bit 2 - enables GLL (4)
* multiple sentences may be selected
*/
/*
* Definitions
*/
#ifdef SYS_WINNT
# define DEVICE "COM%d:" /* COM 1 - 3 supported */
#else
# define DEVICE "/dev/gps%d" /* name of radio device */
#endif
#define SPEED232 B4800 /* uart speed (4800 bps) */
#define PRECISION (-9) /* precision assumed (about 2 ms) */
#define PPS_PRECISION (-20) /* precision assumed (about 1 us) */
#define REFID "GPS\0" /* reference id */
#define DESCRIPTION "NMEA GPS Clock" /* who we are */
#define NANOSECOND 1000000000 /* one second (ns) */
#define RANGEGATE 500000 /* range gate (ns) */
#define LENNMEA 75 /* min timecode length */
/*
* Tables to compute the ddd of year form icky dd/mm timecode. Viva la
* leap.
*/
static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/*
* Unit control structure
*/
struct nmeaunit {
int pollcnt; /* poll message counter */
int polled; /* Hand in a sample? */
l_fp tstamp; /* timestamp of last poll */
#ifdef HAVE_PPSAPI
struct timespec ts; /* last timestamp */
pps_params_t pps_params; /* pps parameters */
pps_info_t pps_info; /* last pps data */
pps_handle_t handle; /* pps handlebars */
#endif /* HAVE_PPSAPI */
};
/*
* Function prototypes
*/
static int nmea_start P((int, struct peer *));
static void nmea_shutdown P((int, struct peer *));
#ifdef HAVE_PPSAPI
static void nmea_control P((int, struct refclockstat *, struct
refclockstat *, struct peer *));
static int nmea_ppsapi P((struct peer *, int, int));
static int nmea_pps P((struct nmeaunit *, l_fp *));
#endif /* HAVE_PPSAPI */
static void nmea_receive P((struct recvbuf *));
static void nmea_poll P((int, struct peer *));
static void gps_send P((int, const char *, struct peer *));
static char *field_parse P((char *, int));
/*
* Transfer vector
*/
struct refclock refclock_nmea = {
nmea_start, /* start up driver */
nmea_shutdown, /* shut down driver */
nmea_poll, /* transmit poll message */
#ifdef HAVE_PPSAPI
nmea_control, /* fudge control */
#else
noentry, /* fudge control */
#endif /* HAVE_PPSAPI */
noentry, /* initialize driver */
noentry, /* buginfo */
NOFLAGS /* not used */
};
/*
* nmea_start - open the GPS devices and initialize data for processing
*/
static int
nmea_start(
int unit,
struct peer *peer
)
{
register struct nmeaunit *up;
struct refclockproc *pp;
int fd;
char device[20];
/*
* Open serial port. Use CLK line discipline, if available.
*/
(void)sprintf(device, DEVICE, unit);
fd = refclock_open(device, SPEED232, LDISC_CLK);
if (fd <= 0) {
#ifdef HAVE_READLINK
/* nmead support added by Jon Miner (cp_n18@yahoo.com)
*
* See http://home.hiwaay.net/~taylorc/gps/nmea-server/
* for information about nmead
*
* To use this, you need to create a link from /dev/gpsX to
* the server:port where nmead is running. Something like this:
*
* ln -s server:port /dev/gps1
*/
char buffer[80];
char *nmea_host;
int nmea_port;
int len;
struct hostent *he;
struct protoent *p;
struct sockaddr_in so_addr;
if ((len = readlink(device,buffer,sizeof(buffer))) == -1)
return(0);
buffer[len] = 0;
if ((nmea_host = strtok(buffer,":")) == NULL)
return(0);
nmea_port = atoi(strtok(NULL,":"));
if ((he = gethostbyname(nmea_host)) == NULL)
return(0);
if ((p = getprotobyname("ip")) == NULL)
return(0);
so_addr.sin_family = AF_INET;
so_addr.sin_port = htons(nmea_port);
so_addr.sin_addr = *((struct in_addr *) he->h_addr);
if ((fd = socket(PF_INET,SOCK_STREAM,p->p_proto)) == -1)
return(0);
if (connect(fd,(struct sockaddr *)&so_addr,SOCKLEN(&so_addr)) == -1) {
close(fd);
return (0);
}
#else
return (0);
#endif
}
/*
* Allocate and initialize unit structure
*/
up = (struct nmeaunit *)emalloc(sizeof(struct nmeaunit));
if (up == NULL) {
(void) close(fd);
return (0);
}
memset((char *)up, 0, sizeof(struct nmeaunit));
pp = peer->procptr;
pp->io.clock_recv = nmea_receive;
pp->io.srcclock = (caddr_t)peer;
pp->io.datalen = 0;
pp->io.fd = fd;
if (!io_addclock(&pp->io)) {
(void) close(fd);
free(up);
return (0);
}
pp->unitptr = (caddr_t)up;
/*
* Initialize miscellaneous variables
*/
peer->precision = PRECISION;
pp->clockdesc = DESCRIPTION;
memcpy((char *)&pp->refid, REFID, 4);
up->pollcnt = 2;
gps_send(pp->io.fd,"$PMOTG,RMC,0000*1D\r\n", peer);
#ifdef HAVE_PPSAPI
/*
* Start the PPSAPI interface if it is there. Default to use
* the assert edge and do not enable the kernel hardpps.
*/
if (time_pps_create(fd, &up->handle) < 0) {
up->handle = 0;
msyslog(LOG_ERR,
"refclock_nmea: time_pps_create failed: %m");
return (1);
}
return(nmea_ppsapi(peer, 0, 0));
#else
return (1);
#endif /* HAVE_PPSAPI */
}
/*
* nmea_shutdown - shut down a GPS clock
*/
static void
nmea_shutdown(
int unit,
struct peer *peer
)
{
register struct nmeaunit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = (struct nmeaunit *)pp->unitptr;
#ifdef HAVE_PPSAPI
if (up->handle != 0)
time_pps_destroy(up->handle);
#endif /* HAVE_PPSAPI */
io_closeclock(&pp->io);
free(up);
}
#ifdef HAVE_PPSAPI
/*
* nmea_control - fudge control
*/
static void
nmea_control(
int unit, /* unit (not used */
struct refclockstat *in, /* input parameters (not uded) */
struct refclockstat *out, /* output parameters (not used) */
struct peer *peer /* peer structure pointer */
)
{
struct refclockproc *pp;
pp = peer->procptr;
nmea_ppsapi(peer, pp->sloppyclockflag & CLK_FLAG2,
pp->sloppyclockflag & CLK_FLAG3);
}
/*
* Initialize PPSAPI
*/
int
nmea_ppsapi(
struct peer *peer, /* peer structure pointer */
int enb_clear, /* clear enable */
int enb_hardpps /* hardpps enable */
)
{
struct refclockproc *pp;
struct nmeaunit *up;
int capability;
pp = peer->procptr;
up = (struct nmeaunit *)pp->unitptr;
if (time_pps_getcap(up->handle, &capability) < 0) {
msyslog(LOG_ERR,
"refclock_nmea: time_pps_getcap failed: %m");
return (0);
}
memset(&up->pps_params, 0, sizeof(pps_params_t));
if (enb_clear)
up->pps_params.mode = capability & PPS_CAPTURECLEAR;
else
up->pps_params.mode = capability & PPS_CAPTUREASSERT;
if (!up->pps_params.mode) {
msyslog(LOG_ERR,
"refclock_nmea: invalid capture edge %d",
!enb_clear);
return (0);
}
up->pps_params.mode |= PPS_TSFMT_TSPEC;
if (time_pps_setparams(up->handle, &up->pps_params) < 0) {
msyslog(LOG_ERR,
"refclock_nmea: time_pps_setparams failed: %m");
return (0);
}
if (enb_hardpps) {
if (time_pps_kcbind(up->handle, PPS_KC_HARDPPS,
up->pps_params.mode & ~PPS_TSFMT_TSPEC,
PPS_TSFMT_TSPEC) < 0) {
msyslog(LOG_ERR,
"refclock_nmea: time_pps_kcbind failed: %m");
return (0);
}
pps_enable = 1;
}
peer->precision = PPS_PRECISION;
#if DEBUG
if (debug) {
time_pps_getparams(up->handle, &up->pps_params);
printf(
"refclock_ppsapi: capability 0x%x version %d mode 0x%x kern %d\n",
capability, up->pps_params.api_version,
up->pps_params.mode, enb_hardpps);
}
#endif
return (1);
}
/*
* Get PPSAPI timestamps.
*
* Return 0 on failure and 1 on success.
*/
static int
nmea_pps(
struct nmeaunit *up,
l_fp *tsptr
)
{
pps_info_t pps_info;
struct timespec timeout, ts;
double dtemp;
l_fp tstmp;
/*
* Convert the timespec nanoseconds field to ntp l_fp units.
*/
if (up->handle == 0)
return (0);
timeout.tv_sec = 0;
timeout.tv_nsec = 0;
memcpy(&pps_info, &up->pps_info, sizeof(pps_info_t));
if (time_pps_fetch(up->handle, PPS_TSFMT_TSPEC, &up->pps_info,
&timeout) < 0)
return (0);
if (up->pps_params.mode & PPS_CAPTUREASSERT) {
if (pps_info.assert_sequence ==
up->pps_info.assert_sequence)
return (0);
ts = up->pps_info.assert_timestamp;
} else if (up->pps_params.mode & PPS_CAPTURECLEAR) {
if (pps_info.clear_sequence ==
up->pps_info.clear_sequence)
return (0);
ts = up->pps_info.clear_timestamp;
} else {
return (0);
}
if ((up->ts.tv_sec == ts.tv_sec) && (up->ts.tv_nsec == ts.tv_nsec))
return (0);
up->ts = ts;
tstmp.l_ui = ts.tv_sec + JAN_1970;
dtemp = ts.tv_nsec * FRAC / 1e9;
tstmp.l_uf = (u_int32)dtemp;
*tsptr = tstmp;
return (1);
}
#endif /* HAVE_PPSAPI */
/*
* nmea_receive - receive data from the serial interface
*/
static void
nmea_receive(
struct recvbuf *rbufp
)
{
register struct nmeaunit *up;
struct refclockproc *pp;
struct peer *peer;
int month, day;
int i;
char *cp, *dp;
int cmdtype;
/* Use these variables to hold data until we decide its worth keeping */
char rd_lastcode[BMAX];
l_fp rd_tmp;
u_short rd_lencode;
/*
* Initialize pointers and read the timecode and timestamp
*/
peer = (struct peer *)rbufp->recv_srcclock;
pp = peer->procptr;
up = (struct nmeaunit *)pp->unitptr;
rd_lencode = (u_short)refclock_gtlin(rbufp, rd_lastcode, BMAX, &rd_tmp);
/*
* There is a case that a <CR><LF> gives back a "blank" line
*/
if (rd_lencode == 0)
return;
#ifdef DEBUG
if (debug)
printf("nmea: gpsread %d %s\n", rd_lencode,
rd_lastcode);
#endif
/*
* We check the timecode format and decode its contents. The
* we only care about a few of them. The most important being
* the $GPRMC format
* $GPRMC,hhmmss,a,fddmm.xx,n,dddmmm.xx,w,zz.z,yyy.,ddmmyy,dd,v*CC
* For Magellan (ColorTrak) GLL probably datum (order of sentences)
* also mode (0,1,2,3) select sentence ANY/ALL, RMC, GGA, GLL
* $GPGLL,3513.8385,S,14900.7851,E,232420.594,A*21
* $GPGGA,232420.59,3513.8385,S,14900.7851,E,1,05,3.4,00519,M,,,,*3F
* $GPRMB,...
* $GPRMC,232418.19,A,3513.8386,S,14900.7853,E,00.0,000.0,121199,12.,E*77
* $GPAPB,...
* $GPGSA,...
* $GPGSV,...
* $GPGSV,...
*/
#define GPXXX 0
#define GPRMC 1
#define GPGGA 2
#define GPGLL 4
cp = rd_lastcode;
cmdtype=0;
if(strncmp(cp,"$GPRMC",6)==0) {
cmdtype=GPRMC;
}
else if(strncmp(cp,"$GPGGA",6)==0) {
cmdtype=GPGGA;
}
else if(strncmp(cp,"$GPGLL",6)==0) {
cmdtype=GPGLL;
}
else if(strncmp(cp,"$GPXXX",6)==0) {
cmdtype=GPXXX;
}
else
return;
/* See if I want to process this message type */
if ( ((peer->ttl == 0) && (cmdtype != GPRMC))
|| ((peer->ttl != 0) && !(cmdtype & peer->ttl)) )
return;
pp->lencode = rd_lencode;
strcpy(pp->a_lastcode,rd_lastcode);
cp = pp->a_lastcode;
pp->lastrec = up->tstamp = rd_tmp;
up->pollcnt = 2;
#ifdef DEBUG
if (debug)
printf("nmea: timecode %d %s\n", pp->lencode,
pp->a_lastcode);
#endif
/* Grab field depending on clock string type */
switch( cmdtype ) {
case GPRMC:
/*
* Test for synchronization. Check for quality byte.
*/
dp = field_parse(cp,2);
if( dp[0] != 'A')
pp->leap = LEAP_NOTINSYNC;
else
pp->leap = LEAP_NOWARNING;
/* Now point at the time field */
dp = field_parse(cp,1);
break;
case GPGGA:
/*
* Test for synchronization. Check for quality byte.
*/
dp = field_parse(cp,6);
if( dp[0] == '0')
pp->leap = LEAP_NOTINSYNC;
else
pp->leap = LEAP_NOWARNING;
/* Now point at the time field */
dp = field_parse(cp,1);
break;
case GPGLL:
/*
* Test for synchronization. Check for quality byte.
*/
dp = field_parse(cp,6);
if( dp[0] != 'A')
pp->leap = LEAP_NOTINSYNC;
else
pp->leap = LEAP_NOWARNING;
/* Now point at the time field */
dp = field_parse(cp,5);
break;
case GPXXX:
return;
default:
return;
}
/*
* Check time code format of NMEA
*/
if( !isdigit((int)dp[0]) ||
!isdigit((int)dp[1]) ||
!isdigit((int)dp[2]) ||
!isdigit((int)dp[3]) ||
!isdigit((int)dp[4]) ||
!isdigit((int)dp[5])
) {
refclock_report(peer, CEVNT_BADREPLY);
return;
}
/*
* Convert time and check values.
*/
pp->hour = ((dp[0] - '0') * 10) + dp[1] - '0';
pp->minute = ((dp[2] - '0') * 10) + dp[3] - '0';
pp->second = ((dp[4] - '0') * 10) + dp[5] - '0';
/* Default to 0 milliseconds, if decimal convert milliseconds in
one, two or three digits
*/
pp->nsec = 0;
if (dp[6] == '.') {
if (isdigit((int)dp[7])) {
pp->nsec = (dp[7] - '0') * 100000000;
if (isdigit((int)dp[8])) {
pp->nsec += (dp[8] - '0') * 10000000;
if (isdigit((int)dp[9])) {
pp->nsec += (dp[9] - '0') * 1000000;
}
}
}
}
if (pp->hour > 23 || pp->minute > 59 || pp->second > 59
|| pp->nsec > 1000000000) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
/*
* Convert date and check values.
*/
if (cmdtype==GPRMC) {
dp = field_parse(cp,9);
day = dp[0] - '0';
day = (day * 10) + dp[1] - '0';
month = dp[2] - '0';
month = (month * 10) + dp[3] - '0';
pp->year = dp[4] - '0';
pp->year = (pp->year * 10) + dp[5] - '0';
}
else {
/* only time */
time_t tt = time(NULL);
struct tm * t = gmtime(&tt);
day = t->tm_mday;
month = t->tm_mon + 1;
pp->year= t->tm_year;
}
if (month < 1 || month > 12 || day < 1) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
/* Hmmmm this will be a nono for 2100,2200,2300 but I don't think I'll be here */
/* good thing that 2000 is a leap year */
/* pp->year will be 00-99 if read from GPS, 00-> (years since 1900) from tm_year */
if (pp->year % 4) {
if (day > day1tab[month - 1]) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
for (i = 0; i < month - 1; i++)
day += day1tab[i];
} else {
if (day > day2tab[month - 1]) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
for (i = 0; i < month - 1; i++)
day += day2tab[i];
}
pp->day = day;
#ifdef HAVE_PPSAPI
/*
* If the PPSAPI is working, rather use its timestamps.
* assume that the PPS occurs on the second so blow any msec
*/
if (nmea_pps(up, &rd_tmp) == 1) {
pp->lastrec = up->tstamp = rd_tmp;
pp->nsec = 0;
}
#endif /* HAVE_PPSAPI */
/*
* Process the new sample in the median filter and determine the
* reference clock offset and dispersion. We use lastrec as both
* the reference time and receive time, in order to avoid being
* cute, like setting the reference time later than the receive
* time, which may cause a paranoid protocol module to chuck out
* the data.
*/
if (!refclock_process(pp)) {
refclock_report(peer, CEVNT_BADTIME);
return;
}
/*
* Only go on if we had been polled.
*/
if (!up->polled)
return;
up->polled = 0;
pp->lastref = pp->lastrec;
refclock_receive(peer);
/* If we get here - what we got from the clock is OK, so say so */
refclock_report(peer, CEVNT_NOMINAL);
record_clock_stats(&peer->srcadr, pp->a_lastcode);
}
/*
* nmea_poll - called by the transmit procedure
*
* We go to great pains to avoid changing state here, since there may be
* more than one eavesdropper receiving the same timecode.
*/
static void
nmea_poll(
int unit,
struct peer *peer
)
{
register struct nmeaunit *up;
struct refclockproc *pp;
pp = peer->procptr;
up = (struct nmeaunit *)pp->unitptr;
if (up->pollcnt == 0)
refclock_report(peer, CEVNT_TIMEOUT);
else
up->pollcnt--;
pp->polls++;
up->polled = 1;
/*
* usually nmea_receive can get a timestamp every second
*/
gps_send(pp->io.fd,"$PMOTG,RMC,0000*1D\r\n", peer);
}
/*
*
* gps_send(fd,cmd, peer) Sends a command to the GPS receiver.
* as gps_send(fd,"rqts,u\r", peer);
*
* We don't currently send any data, but would like to send
* RTCM SC104 messages for differential positioning. It should
* also give us better time. Without a PPS output, we're
* Just fooling ourselves because of the serial code paths
*
*/
static void
gps_send(
int fd,
const char *cmd,
struct peer *peer
)
{
if (write(fd, cmd, strlen(cmd)) == -1) {
refclock_report(peer, CEVNT_FAULT);
}
}
static char *
field_parse(
char *cp,
int fn
)
{
char *tp;
int i = fn;
for (tp = cp; *tp != '\0'; tp++) {
if (*tp == ',')
i--;
if (i == 0)
break;
}
return (++tp);
}
#else
int refclock_nmea_bs;
#endif /* REFCLOCK */