gpsd/gpsd.h

/* gpsd.h -- fundamental types and structures for the gpsd library
 *
 * This file is Copyright (c) 2017 by the GPSD project
 * SPDX-License-Identifier: BSD-2-clause
 */

#ifndef _GPSD_H_
#define _GPSD_H_

#include "compiler.h"	/* Must be outside extern "C" for "atomic"
                         * pulls in gpsd_config.h */

# ifdef __cplusplus
extern "C" {
# endif

#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#ifdef HAVE_WINSOCK2_H
#include <winsock2.h>      /* for fd_set */
#else /* !HAVE_WINSOCK2_H */
#include <sys/select.h>    /* for fd_set */
#endif /* !HAVE_WINSOCK2_H */
#include <time.h>    /* for time_t */

#include "gps.h"
#include "os_compat.h"
#include "ppsthread.h"
#include "timespec.h"

/*
 * Constants for the VERSION response
 * 3.1: Base JSON version
 * 3.2: Added POLL command and response
 * 3.3: AIS app_id split into DAC and FID
 * 3.4: Timestamps change from seconds since Unix epoch to ISO8601.
 * 3.5: POLL subobject name changes: fixes -> tpv, skyview -> sky.
 *      DEVICE::activated becomes ISO8601 rather than real.
 * 3.6  VERSION, WATCH, and DEVICES from slave gpsds get "remote" attribute.
 * 3.7  PPS message added to repertoire. SDDBT water depth reported as
 *      negative altitude with Mode 3 set.
 * 3.8  AIS course member becomes float in scaled mode (bug fix).
 * 3.9  split24 flag added. Controlled-vocabulary fields are now always
 *      dumped in both numeric and string form, with the string being the
 *      value of a synthesized additional attribute with "_text" appended.
 *      (Thus, the 'scaled' flag no longer affects display of these fields.)
 *      PPS drift message ships nsec rather than msec.
 * 3.10 The obsolete tag field has been dropped from JSON.
 * 3.11 A precision field, log2 of the time source jitter, has been added
 *      to the PPS report.  See ntpshm.h for more details.
 * 3.12 OSC message added to repertoire.
 * 3.13 gnssid:svid added to SAT
 *      time added to ATT
 * 3.19 Added RAW message class.
 *      Add cfg_stage and cfg_step, for initialization
 *      Add oldfix2 for better oldfix
 *      Make subtype longer
 *      Add ubx.protver, ubx.last_msgid and more to gps_device_t.ubx
 *      MAX_PACKET_LENGTH 516 -> 9216
 *      Add stuff to gps_device_t.nmea for NMEA 4.1
 * 3.19.1
 *      Remove TIMEHINT_ENABLE.  It only worked when enabled.
 *      Remove NTP_ENABLE and NTPSHM_ENABLE.  It only worked when enabled.
 *      Change gps_type_t.min_cycle from double to timespec_t
 *      Change gps_device_t.last_time from double to timespec_t
 *      Change gps_lexer_t.start_time from timestamp_t to timespec_t
 *      Change gps_context_t.gps_tow from double to timespec_t
 *      Change gps_device_t.sor from timestamp_t to timespec_t
 *      Change gps_device_t.this_frac_time, last_frac_time to timespec_t
 *      Change nmea.subseconds from double to timespec_t
 *      Remove gpsd_gpstime_resolve()
 *      Changed order of gpsd_log() arguments.  Add GPSD_LOG().
 *      Remove gps_device_t.back_to_nmea.
 *      Add fixed_port_speed, fixed_port_framing to gps_context_t.
 *      change tsip.superpkt from bool to int.
 *      Add tsip.machine_id, tsip.hardware_code and tsip.last_tow
 *      Split gps_device_t.subtype into subtype and subtype1
 */
/* Keep in sync with api_major_version and api_minor gps/__init__.py */
#define GPSD_PROTO_MAJOR_VERSION	3   /* bump on incompatible changes */
#define GPSD_PROTO_MINOR_VERSION	14  /* bump on compatible changes */

#define JSON_DATE_MAX	24	/* ISO8601 timestamp with 2 decimal places */

#ifndef DEFAULT_GPSD_SOCKET
#define DEFAULT_GPSD_SOCKET	"/var/run/gpsd.sock"
#endif

/* Some internal capabilities depend on which drivers we're compiling. */
#if !defined(AIVDM_ENABLE) && defined(NMEA2000_ENABLE)
#define AIVDM_ENABLE
#endif
#if !defined(NMEA0183_ENABLE) && (defined(ASHTECH_ENABLE) || defined(FV18_ENABLE) || defined(MTK3301_ENABLE) || defined(TNT_ENABLE) || defined(OCEANSERVER_ENABLE) || defined(GPSCLOCK_ENABLE) || defined(FURY_ENABLE) || defined(SKYTRAQ_ENABLE)   || defined(TRIPMATE_ENABLE))
#define NMEA0183_ENABLE
#endif
#ifdef EARTHMATE_ENABLE
#define ZODIAC_ENABLE
#endif

#if defined(EVERMORE_ENABLE) || \
     defined(GARMIN_ENABLE) || \
     defined(GEOSTAR_ENABLE) || \
     defined(GREIS_ENABLE) || \
     defined(ITRAX_ENABLE) || \
     defined(NAVCOM_ENABLE) || \
     defined(NMEA2000_ENABLE) || \
     defined(ONCORE_ENABLE) || \
     defined(SIRF_ENABLE) || \
     defined(SUPERSTAR2_ENABLE) || \
     defined(TSIP_ENABLE) || \
     defined(UBLOX_ENABLE) || \
     defined(ZODIAC_ENABLE)
#define BINARY_ENABLE
#endif

#if defined(TRIPMATE_ENABLE) || defined(BINARY_ENABLE)
#define NON_NMEA0183_ENABLE
#endif
#if defined(TNT_ENABLE) || defined(OCEANSERVER_ENABLE)
#define COMPASS_ENABLE
#endif
#ifdef ISYNC_ENABLE
#define STASH_ENABLE
#endif

/* First, declarations for the packet layer... */

/*
 * NMEA 3.01, Section 5.3 says the max sentence length shall be
 * 82 chars, including the leading $ and terminating \r\n.
 *
 * Some receivers (TN-200, GSW 2.3.2) emit oversized sentences.
 * The Trimble BX-960 receiver emits a 91-character GGA message.
 * The current hog champion is the Skytraq S2525F8 which emits
 * a 100-character PSTI message.
 */
#define NMEA_MAX	102	/* max length of NMEA sentence */
#define NMEA_BIG_BUF	(2*NMEA_MAX+1)	/* longer than longest NMEA sentence */

/* a few bits of ISGPS magic */
enum isgpsstat_t {
    ISGPS_NO_SYNC, ISGPS_SYNC, ISGPS_SKIP, ISGPS_MESSAGE,
};

#define RTCM_MAX	(RTCM2_WORDS_MAX * sizeof(isgps30bits_t))
/* RTCM is more variable length than RTCM 2 */
#define RTCM3_MAX	512

/*
 * The packet buffers need to be as long than the longest packet we
 * expect to see in any protocol, because we have to be able to hold
 * an entire packet for checksumming...
 * First we thought it had to be big enough for a SiRF Measured Tracker
 * Data packet (188 bytes). Then it had to be big enough for a UBX SVINFO
 * packet (206 bytes). Now it turns out that a couple of ITALK messages are
 * over 512 bytes. I know we like verbose output, but this is ridiculous.
 * Whoopie! The u-blox 8 UBX-RXM-RAWX packet is 8214 byte long!
 */
#define MAX_PACKET_LENGTH	9216	/* 4 + 16 + (256 * 32) + 2 + fudge */

/*
 * UTC of second 0 of week 0 of the first rollover period of GPS time.
 * Used to compute UTC from GPS time. Also, the threshold value
 * under which system clock times are considered unreliable. Often,
 * embedded systems come up thinking it's early 1970 and the system
 * clock will report small positive values until the clock is set.  By
 * choosing this as the cutoff, we'll never reject historical GPS logs
 * that are actually valid.
 */
#define GPS_EPOCH	((time_t)315964800)   /* 6 Jan 1980 00:00:00 UTC */

/* time constant */
#define SECS_PER_DAY	((time_t)(60*60*24))  /* seconds per day */
#define SECS_PER_WEEK	(7*SECS_PER_DAY)        /* seconds per week */
#define GPS_ROLLOVER	(1024*SECS_PER_WEEK)    /* rollover period */

struct gpsd_errout_t {
    int debug;				/* lexer debug level */
    void (*report)(const char *);	/* reporting hook for lexer errors */
    char *label;
};

struct gps_lexer_t {
    /* packet-getter internals */
    int	type;
#define BAD_PACKET      	-1
#define COMMENT_PACKET  	0
#define NMEA_PACKET     	1
#define AIVDM_PACKET    	2
#define GARMINTXT_PACKET	3
#define MAX_TEXTUAL_TYPE	3	/* increment this as necessary */
#define SIRF_PACKET     	4
#define ZODIAC_PACKET   	5
#define TSIP_PACKET     	6
#define EVERMORE_PACKET 	7
#define ITALK_PACKET    	8
#define GARMIN_PACKET   	9
#define NAVCOM_PACKET   	10
#define UBX_PACKET      	11
#define SUPERSTAR2_PACKET	12
#define ONCORE_PACKET   	13
#define GEOSTAR_PACKET   	14
#define NMEA2000_PACKET 	15
#define GREIS_PACKET		16
#define MAX_GPSPACKET_TYPE	16	/* increment this as necessary */
#define RTCM2_PACKET    	17
#define RTCM3_PACKET    	18
#define JSON_PACKET    	    	19
#define PACKET_TYPES		20	/* increment this as necessary */
#define SKY_PACKET     		21
#define TEXTUAL_PACKET_TYPE(n)	((((n)>=NMEA_PACKET) && ((n)<=MAX_TEXTUAL_TYPE)) || (n)==JSON_PACKET)
#define GPS_PACKET_TYPE(n)	(((n)>=NMEA_PACKET) && ((n)<=MAX_GPSPACKET_TYPE))
#define LOSSLESS_PACKET_TYPE(n)	(((n)>=RTCM2_PACKET) && ((n)<=RTCM3_PACKET))
#define PACKET_TYPEMASK(n)	(1 << (n))
#define GPS_TYPEMASK	(((2<<(MAX_GPSPACKET_TYPE+1))-1) &~ PACKET_TYPEMASK(COMMENT_PACKET))
    unsigned int state;
    size_t length;
    unsigned char inbuffer[MAX_PACKET_LENGTH*2+1];
    size_t inbuflen;
    unsigned char *inbufptr;
    /* outbuffer needs to be able to hold 4 GPGSV records at once */
    unsigned char outbuffer[MAX_PACKET_LENGTH*2+1];
    size_t outbuflen;
    unsigned long char_counter;		/* count characters processed */
    unsigned long retry_counter;	/* count sniff retries */
    unsigned counter;			/* packets since last driver switch */
    struct gpsd_errout_t errout;		/* how to report errors */
    timespec_t start_time;		/* time of first input */
    unsigned long start_char;		/* char counter at first input */
    /*
     * ISGPS200 decoding context.
     *
     * This is not conditionalized on RTCM104_ENABLE because we need to
     * be able to build gpsdecode even when RTCM support is not
     * configured in the daemon.
     */
    struct {
	bool            locked;
	int             curr_offset;
	isgps30bits_t   curr_word;
	unsigned int    bufindex;
	/*
	 * Only these should be referenced from elsewhere, and only when
	 * RTCM_MESSAGE has just been returned.
	 */
	isgps30bits_t   buf[RTCM2_WORDS_MAX];   /* packet data */
	size_t          buflen;                 /* packet length in bytes */
    } isgps;
#ifdef PASSTHROUGH_ENABLE
    unsigned int json_depth;
    unsigned int json_after;
#endif /* PASSTHROUGH_ENABLE */
#ifdef STASH_ENABLE
    unsigned char stashbuffer[MAX_PACKET_LENGTH];
    size_t stashbuflen;
#endif /* STASH_ENABLE */
};

extern void lexer_init(struct gps_lexer_t *);
extern void packet_reset(struct gps_lexer_t *);
extern void packet_pushback(struct gps_lexer_t *);
extern void packet_parse(struct gps_lexer_t *);
extern ssize_t packet_get(int, struct gps_lexer_t *);
extern int packet_sniff(struct gps_lexer_t *);
#define packet_buffered_input(lexer) ((lexer)->inbuffer + (lexer)->inbuflen - (lexer)->inbufptr)

/* Next, declarations for the core library... */

/* factors for converting among confidence interval units */
#define CEP50_SIGMA	1.18
#define DRMS_SIGMA	1.414
#define CEP95_SIGMA	2.45

/* this is where we choose the confidence level to use in reports */
#define GPSD_CONFIDENCE	CEP95_SIGMA

#define NTPSHMSEGS	(MAX_DEVICES * 2)	/* number of NTP SHM segments */
#define NTP_MIN_FIXES	3  /* # fixes to wait for before shipping NTP time */


#define AIVDM_CHANNELS	2		/* A, B */

struct gps_device_t;

struct gps_context_t {
    int valid;				/* member validity flags */
#define LEAP_SECOND_VALID	0x01	/* we have or don't need correction */
#define GPS_TIME_VALID  	0x02	/* GPS week/tow is valid */
#define CENTURY_VALID		0x04	/* have received ZDA or 4-digit year */
    struct gpsd_errout_t errout;		/* debug verbosity level and hook */
    bool readonly;			/* if true, never write to device */
    speed_t fixed_port_speed;           // Fixed port speed, if non-zero
    char fixed_port_framing[4];         // Fixed port framing, if non-blank
    /* DGPS status */
    int fixcnt;				/* count of good fixes seen */
    /* timekeeping */
    time_t start_time;			/* local time of daemon startup */
    int leap_seconds;			/* Unix seconds to UTC (GPS-UTC offset) */
    unsigned short gps_week;            /* GPS week, usually 10 bits */
    timespec_t gps_tow;                 /* GPS time of week */
    int century;			/* for NMEA-only devices without ZDA */
    int rollovers;			/* rollovers since start of run */
    int leap_notify;			/* notification state from subframe */
#define LEAP_NOWARNING  0x0     /* normal, no leap second warning */
#define LEAP_ADDSECOND  0x1     /* last minute of day has 60 seconds */
#define LEAP_DELSECOND  0x2     /* last minute of day has 59 seconds */
#define LEAP_NOTINSYNC  0x3     /* overload, clock is free running */
    /* we need the volatile here to tell the C compiler not to
     * 'optimize' as 'dead code' the writes to SHM */
    volatile struct shmTime *shmTime[NTPSHMSEGS];
    bool shmTimeInuse[NTPSHMSEGS];
    void (*pps_hook)(struct gps_device_t *, struct timedelta_t *);
#ifdef SHM_EXPORT_ENABLE
    /* we don't want the compiler to treat writes to shmexport as dead code,
     * and we don't want them reordered either */
    volatile void *shmexport;
    int shmid;				/* ID of SHM  (for later IPC_RMID) */
#endif
    ssize_t (*serial_write)(struct gps_device_t *,
			    const char *buf, const size_t len);
};

/* state for resolving interleaved Type 24 packets */
struct ais_type24a_t {
    unsigned int mmsi;
    char shipname[AIS_SHIPNAME_MAXLEN+1];
};
#define MAX_TYPE24_INTERLEAVE	8	/* max number of queued type 24s */
struct ais_type24_queue_t {
    struct ais_type24a_t ships[MAX_TYPE24_INTERLEAVE];
    int index;
};

/* state for resolving AIVDM decodes */
struct aivdm_context_t {
    /* hold context for decoding AIDVM packet sequences */
    int decoded_frags;		/* for tracking AIDVM parts in a multipart sequence */
    unsigned char bits[2048];
    size_t bitlen; /* how many valid bits */
    struct ais_type24_queue_t type24_queue;
};

#define MODE_NMEA	0
#define MODE_BINARY	1

typedef enum {ANY, GPS, RTCM2, RTCM3, AIS} gnss_type;
typedef enum {
    event_wakeup,
    event_triggermatch,
    event_identified,
    event_configure,
    event_driver_switch,
    event_deactivate,
    event_reactivate,
} event_t;


#define INTERNAL_SET(n)	((gps_mask_t)(1llu<<(SET_HIGH_BIT+(n))))
#define RAW_IS  	INTERNAL_SET(1) 	/* raw pseudoranges available */
#define USED_IS 	INTERNAL_SET(2) 	/* sat-used count available */
#define DRIVER_IS	INTERNAL_SET(3) 	/* driver type identified */
#define CLEAR_IS	INTERNAL_SET(4) 	/* starts a reporting cycle */
#define REPORT_IS	INTERNAL_SET(5) 	/* ends a reporting cycle */
#define NODATA_IS	INTERNAL_SET(6) 	/* no data read from fd */
#define NTPTIME_IS	INTERNAL_SET(7) 	/* precision time is available */
#define PERR_IS 	INTERNAL_SET(8) 	/* PDOP set */
#define PASSTHROUGH_IS 	INTERNAL_SET(9) 	/* passthrough mode */
#define EOF_IS		INTERNAL_SET(10)	/* synthetic EOF */
#define GOODTIME_IS	INTERNAL_SET(11) 	/* time good even if no pos fix */
#define DATA_IS	~(ONLINE_SET|PACKET_SET|CLEAR_IS|REPORT_IS)

typedef unsigned int driver_mask_t;
#define DRIVER_NOFLAGS	0x00000000u
#define DRIVER_STICKY	0x00000001u

/*
 * True if a device type is non-null and has control methods.
 */
#define CONTROLLABLE(dp)	(((dp) != NULL) && \
				 ((dp)->speed_switcher != NULL		\
				  || (dp)->mode_switcher != NULL	\
				  || (dp)->rate_switcher != NULL))

/*
 * True if a driver selection of it should be sticky.
 */
#define STICKY(dp)		((dp) != NULL && ((dp)->flags & DRIVER_STICKY) != 0)

struct gps_type_t {
/* GPS method table, describes how to talk to a particular GPS type */
    char *type_name;
    int packet_type;
    driver_mask_t flags;	/* reserved for expansion */
    char *trigger;
    int channels;
    bool (*probe_detect)(struct gps_device_t *session);
    ssize_t (*get_packet)(struct gps_device_t *session);
    gps_mask_t (*parse_packet)(struct gps_device_t *session);
    ssize_t (*rtcm_writer)(struct gps_device_t *session, const char *rtcmbuf, size_t rtcmbytes);
    void (*init_query)(struct gps_device_t *session);
    void (*event_hook)(struct gps_device_t *session, event_t event);
#ifdef RECONFIGURE_ENABLE
#ifdef HAVE_TERMIOS_H
    bool (*speed_switcher)(struct gps_device_t *session,
				     speed_t speed, char parity, int stopbits);
    void (*mode_switcher)(struct gps_device_t *session, int mode);
    bool (*rate_switcher)(struct gps_device_t *session, double rate);
    timespec_t min_cycle;
#endif /* HAVE_TERMIOS_H */
#endif /* RECONFIGURE_ENABLE */
#ifdef CONTROLSEND_ENABLE
    ssize_t (*control_send)(struct gps_device_t *session, char *buf, size_t buflen);
#endif /* CONTROLSEND_ENABLE */
    double (*time_offset)(struct gps_device_t *session);
};

/*
 * Each input source has an associated type.  This is currently used in two
 * ways:
 *
 * (1) To determince if we require that gpsd be the only process opening a
 * device.  We make an exception for PTYs because the master side has to be
 * opened by test code.
 *
 * (2) To determine whether it's safe to send wakeup strings.  These are
 * required on some unusual RS-232 devices (such as the TNT compass and
 * Thales/Ashtech GPSes) but should not be shipped to unidentified USB
 * or Bluetooth devices as we don't even know in advance those are GPSes;
 * they might not cope well.
 *
 * Where it says "case detected but not used" it means that we can identify
 * a source type but no behavior is yet contingent on it.  A "discoverable"
 * device is one for which there is discoverable metadata such as a
 * vendor/product ID.
 *
 * We should never see a block device; that would indicate a serious error
 * in command-line usage or the hotplug system.
 */
typedef enum {source_unknown,
	      source_blockdev,	/* block devices can't be GPS sources */
	      source_rs232,	/* potential GPS source, not discoverable */
	      source_usb,	/* potential GPS source, discoverable */
	      source_bluetooth,	/* potential GPS source, discoverable */
	      source_can,	/* potential GPS source, fixed CAN format */
	      source_pty,	/* PTY: we don't require exclusive access */
	      source_tcp,	/* TCP/IP stream: case detected but not used */
	      source_udp,	/* UDP stream: case detected but not used */
	      source_gpsd,	/* Remote gpsd instance over TCP/IP */
	      source_pps,	/* PPS-only device, such as /dev/ppsN */
	      source_pipe,	/* Unix FIFO; don't use blocking I/O */
} sourcetype_t;

/*
 * Each input source also has an associated service type.
 */
typedef enum {service_unknown,
	      service_sensor,
	      service_dgpsip,
	      service_ntrip,
} servicetype_t;

/*
 * Private state information about an NTRIP stream.
 */
struct ntrip_stream_t
{
    char mountpoint[101];
    char credentials[128];
    char authStr[128];
    char url[256];
    char port[32]; /* in my /etc/services 16 was the longest */
    bool set; /* found and set */
    enum
    {
	fmt_rtcm2,
	fmt_rtcm2_0,
	fmt_rtcm2_1,
	fmt_rtcm2_2,
	fmt_rtcm2_3,
	fmt_rtcm3_0,
	fmt_rtcm3_1,
	fmt_rtcm3_2,
	fmt_rtcm3_3,
	fmt_unknown
    } format;
    int carrier;
    double latitude;
    double longitude;
    int nmea;
    enum
    { cmp_enc_none, cmp_enc_unknown } compr_encryp;
    enum
    { auth_none, auth_basic, auth_digest, auth_unknown } authentication;
    int fee;
    int bitrate;
};

struct gps_device_t {
/* session object, encapsulates all global state */
    struct gps_data_t gpsdata;
    const struct gps_type_t *device_type;
    unsigned int driver_index;	      /* numeric index of current driver */
    unsigned int drivers_identified;  /* bitmask; what drivers have we seen? */
    unsigned int cfg_stage;	/* configuration stage counter */
    unsigned int cfg_step;	/* configuration step counter */
#ifdef RECONFIGURE_ENABLE
    const struct gps_type_t *last_controller;
#endif /* RECONFIGURE_ENABLE */
    struct gps_context_t	*context;
    sourcetype_t sourcetype;
    servicetype_t servicetype;
    int mode;
#ifdef HAVE_TERMIOS_H
    struct termios ttyset, ttyset_old;
#endif
    unsigned int baudindex;
    int saved_baud;
    struct gps_lexer_t lexer;
    int badcount;
    int subframe_count;
    /* firmware version or subtype ID, 96 too small for ZED-F9 */
    char subtype[128];
    char subtype1[128];
    time_t opentime;
    time_t releasetime;
    bool zerokill;
    time_t reawake;
    timespec_t sor;	        /* time start of this reporting cycle */
    unsigned long chars;	/* characters in the cycle */
    bool ship_to_ntpd;
    volatile struct shmTime *shm_clock;
    volatile struct shmTime *shm_pps;
    int chronyfd;			/* for talking to chrony */
    volatile struct pps_thread_t pps_thread;
    /*
     * msgbuf needs to hold the hex decode of inbuffer
     * so msgbuf must be 2x the size of inbuffer
     */
    char msgbuf[MAX_PACKET_LENGTH*4+1];	/* command message buffer for sends */
    size_t msgbuflen;
    int observed;			/* which packet type`s have we seen? */
    bool cycle_end_reliable;		/* does driver signal REPORT_MASK */
    int fixcnt;				/* count of fixes from this device */
    struct gps_fix_t newdata;		/* where drivers put their data */
    struct gps_fix_t lastfix;		/* not qute yet ready for oldfix */
    struct gps_fix_t oldfix;		/* previous fix for error modeling */
#ifdef NMEA0183_ENABLE
    struct {
	unsigned short sats_used[MAXCHANNELS];
	int part, await;		/* for tracking GSV parts */
	struct tm date;	                /* date part of last sentence time */
	timespec_t subseconds;		/* subsec part of last sentence time */
	char *field[NMEA_MAX];
	unsigned char fieldcopy[NMEA_MAX+1];
	/* detect receivers that ship GGA with non-advancing timestamp */
	bool latch_mode;
	char last_gga_timestamp[16];
	char last_gga_talker;
        /* GSV stuff */
	bool seen_bdgsv;
	bool seen_gagsv;
	bool seen_glgsv;
	bool seen_gpgsv;
	bool seen_qzss;
	char last_gsv_talker;
	unsigned char last_gsv_sigid;           /* NMEA 4.1 */
        /* GSA stuff */
	bool seen_glgsa;
	bool seen_gngsa;
	bool seen_bdgsa;
	bool seen_gagsa;
	char last_gsa_talker;
	/*
	 * State for the cycle-tracking machinery.
	 * The reason these timestamps are separate from the
	 * general sentence timestamps is that we can
	 * use the minutes and seconds part of a sentence
	 * with an incomplete timestamp (like GGA) for
	 * end-cycle recognition, even if we don't have a previous
	 * RMC or ZDA that lets us get full time from it.
	 */
	timespec_t this_frac_time, last_frac_time;
	bool latch_frac_time;
	int lasttag;              /* index into nmea_phrase[] */
	uint64_t cycle_enders;    /* bit map into nmea_phrase{} */
	bool cycle_continue;
    } nmea;
#endif /* NMEA0183_ENABLE */
    /*
     * The rest of this structure is driver-specific private storage.
     * Only put a driver's scratch storage in here if it is never
     * implemented on the same device that supports any mode already
     * in this union; otherwise bad things might happen after a device
     * mode switch.
     */
    union {
#ifdef BINARY_ENABLE
#ifdef GEOSTAR_ENABLE
	struct {
	    unsigned int physical_port;
	} geostar;
#endif /* GEOSTAR_ENABLE */
#ifdef GREIS_ENABLE
	struct {
	    uint32_t rt_tod;		/* RT message time of day (modulo 1 day) */
	    bool seen_rt;		/* true if seen RT message */
	    bool seen_uo;		/* true if seen UO message */
	    bool seen_si;		/* true if seen SI message */
	    bool seen_az;		/* true if seen AZ message */
	    bool seen_ec;		/* true if seen EC message */
	    bool seen_el;		/* true if seen EL message */
            /* true if seen a raw measurement message */
	    bool seen_raw;
	} greis;
#endif /* GREIS_ENABLE */
#ifdef SIRF_ENABLE
	struct {
	    unsigned int need_ack;	/* if NZ we're awaiting ACK */
	    unsigned int driverstate;	/* for private use */
#define SIRF_LT_231	0x01		/* SiRF at firmware rev < 231 */
#define SIRF_EQ_231     0x02            /* SiRF at firmware rev == 231 */
#define SIRF_GE_232     0x04            /* SiRF at firmware rev >= 232 */
#define UBLOX   	0x08		/* u-blox firmware with packet 0x62 */
	    unsigned long satcounter;
	    unsigned int time_seen;
	    unsigned char lastid;	/* ID with last timestamp seen */
#define TIME_SEEN_UTC_2	0x08	/* Seen UTC time variant 2? */
	    /* fields from Navigation Parameters message */
	    bool nav_parameters_seen;	/* have we seen one? */
	    unsigned char altitude_hold_mode;
	    unsigned char altitude_hold_source;
	    int16_t altitude_source_input;
	    unsigned char degraded_mode;
	    unsigned char degraded_timeout;
	    unsigned char dr_timeout;
	    unsigned char track_smooth_mode;
	    /* fields from DGPS Status */
	    unsigned int dgps_source;
#define SIRF_DGPS_SOURCE_NONE		0 /* No DGPS correction type have been selected */
#define SIRF_DGPS_SOURCE_SBAS		1 /* SBAS */
#define SIRF_DGPS_SOURCE_SERIAL		2 /* RTCM corrections */
#define SIRF_DGPS_SOURCE_BEACON		3 /* Beacon corrections */
#define SIRF_DGPS_SOURCE_SOFTWARE	4 /*  Software API corrections */
	} sirf;
#endif /* SIRF_ENABLE */
#ifdef SUPERSTAR2_ENABLE
	struct {
	    time_t last_iono;
	} superstar2;
#endif /* SUPERSTAR2_ENABLE */
#ifdef TSIP_ENABLE
	struct {
	    unsigned short sats_used[MAXCHANNELS];
            /* Super Packet mode requested.
             * 0 = None, 1 = old superpacket, 2 = new superpacket (SMT 360) */
	    uint8_t superpkt;
	    uint8_t machine_id;         // from 0x4b
	    uint16_t hardware_code;     // from 0x1c-83
	    time_t last_41;		/* Timestamps for packet requests */
	    time_t last_48;
	    time_t last_5c;
	    time_t last_6d;
	    time_t last_46;
	    time_t req_compact;
	    unsigned int stopbits; /* saved RS232 link parameter */
	    char parity;
	    int subtype;                // hardware ID, sort of
#define TSIP_UNKNOWN            0
#define TSIP_ACUTIME_GOLD       3001
#define TSIP_RESSMT360          3023
#define TSIP_ICMSMT360          3026
#define TSIP_RES36017x22        3031
            uint8_t alt_is_msl;         // 0 if alt is HAE, 1 if MSL
            timespec_t last_tow;        // used to find cycle start
	} tsip;
#endif /* TSIP_ENABLE */
#ifdef GARMIN_ENABLE	/* private housekeeping stuff for the Garmin driver */
	struct {
	    unsigned char Buffer[4096+12];	/* Garmin packet buffer */
	    size_t BufferLen;		/* current GarminBuffer Length */
	} garmin;
#endif /* GARMIN_ENABLE */
#ifdef ZODIAC_ENABLE	/* private housekeeping stuff for the Zodiac driver */
	struct {
	    unsigned short sn;		/* packet sequence number */
	    /*
	     * Zodiac chipset channel status from PRWIZCH. Keep it so
	     * raw-mode translation of Zodiac binary protocol can send
	     * it up to the client.
	     */
#define ZODIAC_CHANNELS	12
	    unsigned int Zs[ZODIAC_CHANNELS];	/* satellite PRNs */
	    unsigned int Zv[ZODIAC_CHANNELS];	/* signal values (0-7) */
	} zodiac;
#endif /* ZODIAC_ENABLE */
#ifdef UBLOX_ENABLE
	struct {
	    unsigned char port_id;
	    unsigned char sbas_in_use;
	    unsigned char protver;              /* u-blox protocol version */
	    unsigned int last_msgid;            /* last class/ID */
            /* FIXME: last_time set but never used? */
            timespec_t last_time;               /* time of last_msgid */
	    unsigned int end_msgid;             /* cycle ender class/ID */
            /* iTOW, and last_iTOW, in ms, used for cycle end detect. */
            int64_t iTOW;
            int64_t last_iTOW;
    	} ubx;
#endif /* UBLOX_ENABLE */
#ifdef NAVCOM_ENABLE
	struct {
	    uint8_t physical_port;
	    bool warned;
	} navcom;
#endif /* NAVCOM_ENABLE */
#ifdef ONCORE_ENABLE
	struct {
#define ONCORE_VISIBLE_CH 12
	    int visible;
	    int PRN[ONCORE_VISIBLE_CH];		/* PRNs of satellite */
	    int elevation[ONCORE_VISIBLE_CH];	/* elevation of satellite */
	    int azimuth[ONCORE_VISIBLE_CH];	/* azimuth */
	    int pps_offset_ns;
	} oncore;
#endif /* ONCORE_ENABLE */
#ifdef NMEA2000_ENABLE
	struct {
	    unsigned int can_msgcnt;
	    unsigned int can_net;
	    unsigned int unit;
	    bool unit_valid;
	    int mode;
	    unsigned int mode_valid;
	    unsigned int idx;
//	    size_t ptr;
	    size_t fast_packet_len;
	    int type;
	    void *workpgn;
	    void *pgnlist;
	    unsigned char sid[8];
	} nmea2000;
#endif /* NMEA2000_ENABLE */
	/*
	 * This is not conditionalized on RTCM104_ENABLE because we need to
	 * be able to build gpsdecode even when RTCM support is not
	 * configured in the daemon.  It doesn't take up extra space.
	 */
	struct {
	    /* ISGPS200 decoding */
	    bool            locked;
	    int             curr_offset;
	    isgps30bits_t   curr_word;
	    isgps30bits_t   buf[RTCM2_WORDS_MAX];
	    unsigned int    bufindex;
	} isgps;
#endif /* BINARY_ENABLE */
#ifdef AIVDM_ENABLE
	struct {
	    struct aivdm_context_t context[AIVDM_CHANNELS];
	    char ais_channel;
	} aivdm;
#endif /* AIVDM_ENABLE */
    } driver;

    /*
     * State of an NTRIP connection.  We don't want to zero this on every
     * activation, otherwise the connection state will get lost.  Information
     * in this substructure is only valid if servicetype is service_ntrip.
     */
    struct {
	/* state information about the stream */
	struct ntrip_stream_t stream;

	/* state information about our response parsing */
	enum {
	    ntrip_conn_init,
	    ntrip_conn_sent_probe,
	    ntrip_conn_sent_get,
	    ntrip_conn_established,
	    ntrip_conn_err
	} conn_state; 	/* connection state for multi stage connect */
	bool works;		/* marks a working connection, so we try to reconnect once */
	bool sourcetable_parse;	/* have we read the sourcetable header? */
    } ntrip;
    /* State of a DGPSIP connection */
    struct {
	bool reported;
    } dgpsip;
};

/*
 * These are used where a file descriptor of 0 or greater indicaes open device.
 */
#define UNALLOCATED_FD	-1	/* this slot is available for reallocation */
#define PLACEHOLDING_FD	-2	/* this slot *not* available for reallocation */

/* logging levels */
#define LOG_ERROR 	-1	/* errors, display always */
#define LOG_SHOUT	0	/* not an error but we should always see it */
#define LOG_WARN	1	/* not errors but may indicate a problem */
#define LOG_CLIENT	2	/* log JSON reports to clients */
#define LOG_INF 	3	/* key informative messages */
#define LOG_PROG	4	/* progress messages */
#define LOG_IO  	5	/* IO to and from devices */
#define LOG_DATA	6	/* log data management messages */
#define LOG_SPIN	7	/* logging for catching spin bugs */
#define LOG_RAW 	8	/* raw low-level I/O */

#define ISGPS_ERRLEVEL_BASE	LOG_RAW

#define IS_HIGHEST_BIT(v,m)	(v & ~((m<<1)-1))==0

/* driver helper functions */
extern void isgps_init(struct gps_lexer_t *);
enum isgpsstat_t isgps_decode(struct gps_lexer_t *,
			      bool (*preamble_match)(isgps30bits_t *),
			      bool (*length_check)(struct gps_lexer_t *),
			      size_t,
			      unsigned int);
extern unsigned int isgps_parity(isgps30bits_t);
extern void isgps_output_magnavox(const isgps30bits_t *, unsigned int, FILE *);

extern enum isgpsstat_t rtcm2_decode(struct gps_lexer_t *, unsigned int);
extern void json_rtcm2_dump(const struct rtcm2_t *,
			    const char *, char[], size_t);
extern void rtcm2_unpack(struct rtcm2_t *, char *);
extern void json_rtcm3_dump(const struct rtcm3_t *,
			    const char *, char[], size_t);
extern void rtcm3_unpack(const struct gps_context_t *,
			 struct rtcm3_t *, char *);

/* here are the available GPS drivers */
extern const struct gps_type_t **gpsd_drivers;

/* gpsd library internal prototypes */
extern gps_mask_t generic_parse_input(struct gps_device_t *);
extern ssize_t generic_get(struct gps_device_t *);

extern gps_mask_t nmea_parse(char *, struct gps_device_t *);
extern ssize_t nmea_write(struct gps_device_t *, char *, size_t);
extern ssize_t nmea_send(struct gps_device_t *, const char *, ... );
extern void nmea_add_checksum(char *);

extern gps_mask_t sirf_parse(struct gps_device_t *, unsigned char *, size_t);
extern gps_mask_t evermore_parse(struct gps_device_t *, unsigned char *, size_t);
extern gps_mask_t navcom_parse(struct gps_device_t *, unsigned char *, size_t);
extern gps_mask_t garmin_ser_parse(struct gps_device_t *);
extern gps_mask_t garmintxt_parse(struct gps_device_t *);
extern gps_mask_t aivdm_parse(struct gps_device_t *);

extern bool netgnss_uri_check(char *);
extern int netgnss_uri_open(struct gps_device_t *, char *);
extern void netgnss_report(struct gps_context_t *,
			 struct gps_device_t *,
			 struct gps_device_t *);
extern void netgnss_autoconnect(struct gps_context_t *, double, double);

extern int dgpsip_open(struct gps_device_t *, const char *);
extern void dgpsip_report(struct gps_context_t *,
			 struct gps_device_t *,
			 struct gps_device_t *);
extern void dgpsip_autoconnect(struct gps_context_t *,
			       double, double, const char *);
extern int ntrip_open(struct gps_device_t *, char *);
extern void ntrip_report(struct gps_context_t *,
			 struct gps_device_t *,
			 struct gps_device_t *);

extern void gpsd_tty_init(struct gps_device_t *);
extern int gpsd_serial_open(struct gps_device_t *);
extern bool gpsd_set_raw(struct gps_device_t *);
extern ssize_t gpsd_serial_write(struct gps_device_t *,
				 const char *, const size_t);
extern bool gpsd_next_hunt_setting(struct gps_device_t *);
extern int gpsd_switch_driver(struct gps_device_t *, char *);
#ifdef HAVE_TERMIOS_H
extern void gpsd_set_speed(struct gps_device_t *, speed_t, char, unsigned int);
extern speed_t gpsd_get_speed(const struct gps_device_t *);
extern speed_t gpsd_get_speed_old(const struct gps_device_t *);
#endif /* HAVE_TERMIOS_H */
extern int gpsd_get_stopbits(const struct gps_device_t *);
extern char gpsd_get_parity(const struct gps_device_t *);
extern void gpsd_assert_sync(struct gps_device_t *);
extern void gpsd_close(struct gps_device_t *);

extern ssize_t gpsd_write(struct gps_device_t *, const char *, const size_t);

extern void gpsd_time_init(struct gps_context_t *, time_t);
extern void gpsd_set_century(struct gps_device_t *);
extern timespec_t gpsd_gpstime_resolv(struct gps_device_t *,
			      const unsigned short, const timespec_t);
extern timespec_t gpsd_utc_resolve(struct gps_device_t *);
extern void gpsd_century_update(struct gps_device_t *, int);

extern void gpsd_zero_satellites(struct gps_data_t *sp);
extern gps_mask_t gpsd_interpret_subframe(struct gps_device_t *, unsigned int,
				uint32_t[]);
extern gps_mask_t gpsd_interpret_subframe_raw(struct gps_device_t *,
				unsigned int, uint32_t[]);
extern const char *gpsd_hexdump(char *, size_t, char *, size_t);
extern const char *gpsd_packetdump(char *, size_t, char *, size_t);
extern const char *gpsd_prettydump(struct gps_device_t *);
# ifdef __cplusplus
extern "C" {
# endif
extern int gpsd_hexpack(const char *, char *, size_t);
# ifdef __cplusplus
}
# endif
extern ssize_t hex_escapes(char *, const char *);
extern void gpsd_position_fix_dump(struct gps_device_t *,
				   char[], size_t);
extern void gpsd_clear_data(struct gps_device_t *);
extern socket_t netlib_connectsock(int, const char *, const char *, const char *);
extern socket_t netlib_localsocket(const char *, int);
extern const char *netlib_errstr(const int);
extern char *netlib_sock2ip(socket_t);

extern void nmea_tpv_dump(struct gps_device_t *, char[], size_t);
extern void nmea_sky_dump(struct gps_device_t *, char[], size_t);
extern void nmea_subframe_dump(struct gps_device_t *, char[], size_t);
extern void nmea_ais_dump(struct gps_device_t *, char[], size_t);
extern unsigned int ais_binary_encode(struct ais_t *ais, unsigned char *bits, int flag);

extern void ntp_latch(struct gps_device_t *device,  struct timedelta_t *td);
extern void ntpshm_context_init(struct gps_context_t *);
extern void ntpshm_session_init(struct gps_device_t *);
extern int ntpshm_put(struct gps_device_t *, volatile struct shmTime *, struct timedelta_t *);
extern void ntpshm_link_deactivate(struct gps_device_t *);
extern void ntpshm_link_activate(struct gps_device_t *);

extern void errout_reset(struct gpsd_errout_t *errout);

extern void gpsd_acquire_reporting_lock(void);
extern void gpsd_release_reporting_lock(void);

extern gps_mask_t ecef_to_wgs84fix(struct gps_fix_t *,
                                   double, double, double,
                                   double, double, double);
extern void clear_dop(struct dop_t *);

/* shmexport.c */
#define GPSD_SHM_KEY	0x47505344	/* "GPSD" */
struct shmexport_t
{
    int bookend1;
    struct gps_data_t gpsdata;
    int bookend2;
};
extern bool shm_acquire(struct gps_context_t *);
extern void shm_release(struct gps_context_t *);
extern void shm_update(struct gps_context_t *, struct gps_data_t *);

/* dbusexport.c */
#if defined(DBUS_EXPORT_ENABLE)
int initialize_dbus_connection (void);
void send_dbus_fix (struct gps_device_t* channel);
#endif /* defined(DBUS_EXPORT_ENABLE) */

/* srecord.c */
extern void hexdump(size_t, unsigned char *, unsigned char *);
extern unsigned char sr_sum(unsigned int, unsigned int, unsigned char *);
extern int bin2srec(unsigned int, unsigned int, unsigned int, unsigned char *, unsigned char *);
extern int srec_hdr(unsigned int, unsigned char *, unsigned char *);
extern int srec_fin(unsigned int, unsigned char *);
extern unsigned char hc(unsigned char);

/* a BSD transplant */
int b64_ntop(unsigned char const *src, size_t srclength, char *target,
    size_t targsize);

/* application interface */
extern void gps_context_init(struct gps_context_t *context,
			     const char *label);
extern void gpsd_init(struct gps_device_t *,
		      struct gps_context_t *,
		      const char *);
extern void gpsd_clear(struct gps_device_t *);
extern int gpsd_open(struct gps_device_t *);
#define O_CONTINUE	0
#define O_PROBEONLY	1
#define O_OPTIMIZE	2
extern int gpsd_activate(struct gps_device_t *, const int);
extern void gpsd_deactivate(struct gps_device_t *);

#define AWAIT_GOT_INPUT	1
#define AWAIT_NOT_READY	0
#define AWAIT_FAILED	-1
extern int gpsd_await_data(fd_set *,
			   fd_set *,
			    const int,
			    fd_set *,
			    struct gpsd_errout_t *errout);
extern gps_mask_t gpsd_poll(struct gps_device_t *);
#define DEVICE_EOF	-3
#define DEVICE_ERROR	-2
#define DEVICE_UNREADY	-1
#define DEVICE_READY	1
#define DEVICE_UNCHANGED	0
extern int gpsd_multipoll(const bool,
			  struct gps_device_t *,
			  void (*)(struct gps_device_t *, gps_mask_t),
			  float reawake_time);
extern void gpsd_wrap(struct gps_device_t *);
extern bool gpsd_add_device(const char *device_name, bool flag_nowait);
extern const char *gpsd_maskdump(gps_mask_t);

/* exceptional driver methods */
extern bool ubx_write(struct gps_device_t *, unsigned int, unsigned int,
		      unsigned char *, size_t);
extern bool ais_binary_decode(const struct gpsd_errout_t *errout,
			      struct ais_t *ais,
			      const unsigned char *, size_t,
			      struct ais_type24_queue_t *);

void gpsd_labeled_report(const int, const int,
			 const char *, const char *, va_list);

// do not call gpsd_log() directly, use GPSD_LOG() to save a lot of cpu time
PRINTF_FUNC(3, 4) void gpsd_log(const int, const struct gpsd_errout_t *,
                                const char *, ...);

/*
 * GPSD_LOG() is the new one debug logger to rule them all.
 *
 * The calling convention is not attractive:
 *     GPSD_LOG(debuglevel, (fmt, ...));
 *     GPSD_LOG(2, ("this will appear on stdout if debug >= %d\n", 2));
 *
 * This saves significant pushing, popping, hexification, etc. when
 * the debug level does not require it.
 */
#define GPSD_LOG(lvl, eo, ...)           \
    do {                                 \
        if ((eo)->debug >= (lvl))        \
            gpsd_log(lvl, eo, __VA_ARGS__);   \
    } while (0)



#define NITEMS(x) ((int) (sizeof(x) / sizeof(x[0]) + COMPILE_CHECK_IS_ARRAY(x)))

/*
 * C99 requires NAN to be defined if the implementation supports quiet
 * NANs.  At one point, it seems Solaris did not define NAN; it is not
 * clear if this is still true.
 */
#ifndef NAN
#define NAN (0.0f/0.0f)
#endif

#if !defined(HAVE_CFMAKERAW)
/*
 * POSIX does not specify cfmakeraw, but it is pretty common.  We
 * provide an implementation in serial.c for systems that lack it.
 */
void cfmakeraw(struct termios *);
#endif /* !defined(HAVE_CFMAKERAW) */

#define DEVICEHOOKPATH "/" SYSCONFDIR "/gpsd/device-hook"

# ifdef __cplusplus
}
# endif

#endif /* _GPSD_H_ */
// Local variables:
// mode: c
// end: