src/fap.c File Reference

Implementation of public interface. More...

#include "fap.h"
#include "helpers.h"
#include "helpers2.h"
#include "regs.h"
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include <ctype.h>
#include <math.h>
#include <stdio.h>

Include dependency graph for fap.c:

Go to the source code of this file.

Defines
#define	PI   3.14159265
	The magic constant.
#define	DEG2RAD(x)   (x/360*2*PI)
	Degrees to radians.
#define	RAD2DEG(x)   (x*(180/PI))
	Radians to degrees.
#define	FEND   0xc0
	KISS frame start and end delimeter.
#define	FESC   0xdb
	KISS frame escape byte.
#define	TFEND   0xdc
	Escaped FEND.
#define	TFESC   0xdd
	Escaped FESC.
#define	FRAME_MAXLEN   512
	Size of buffers reserved for frame conversions.
#define	AX25_FRAME_UI   0x03
	UI-frame identification byte.
#define	AX25_PID_APRS   0xf0
	Protocol id of APRS in AX.25 frame.
Functions
fap_packet_t *	fap_parseaprs (char const *input, unsigned int const input_len, short const is_ax25)
	The parser.
void	fap_explain_error (fap_error_code_t const error, char *output)
	Return human-readable error message for given error code.
void	fap_mice_mbits_to_message (char const *bits, char *output)
	Convert mic-e message bits (three numbers 0-2) to a textual message.
double	fap_distance (double lon0, double lat0, double lon1, double lat1)
	Calculate distance between given locations.
double	fap_direction (double lon0, double lat0, double lon1, double lat1)
	Calculate direction from first to second location.
int	fap_count_digihops (fap_packet_t const *packet)
	Count amount of digihops the packet has gone through.
char *	fap_check_ax25_call (char const *input, short const add_ssid0)
	Check if the callsign is a valid AX.25 callsign.
int	fap_kiss_to_tnc2 (char const *kissframe, unsigned int kissframe_len, char *tnc2frame, unsigned int *tnc2frame_len, unsigned int *tnc_id)
	Convert a KISS-frame into a TNC-2 compatible UI-frame.
int	fap_ax25_to_tnc2 (char const *ax25frame, unsigned int ax25frame_len, char *tnc2frame, unsigned int *tnc2frame_len)
	Convert raw AX.25 frame into TNC-2 compatible UI-frame.
int	fap_tnc2_to_kiss (char const *tnc2frame, unsigned int tnc2frame_len, unsigned int const tnc_id, char *kissframe, unsigned int *kissframe_len)
	Convert a TNC-2 compatible UI-frame into a KISS data frame.
int	fap_tnc2_to_ax25 (char const *tnc2frame, unsigned int tnc2frame_len, char *ax25frame, unsigned int *ax25frame_len)
	Convert TNC-2 compatible UI-frame into raw AX.25-frame.
void	fap_init ()
	Library initialization.
void	fap_cleanup ()
	Library cleanup.
void	fap_free (fap_packet_t *packet)
	Custom free() for fap_packet_t*.
Variables
regex_t	fapint_regex_header
regex_t	fapint_regex_ax25call
regex_t	fapint_regex_digicall
regex_t	fapint_regex_digicallv6
regex_t	fapint_regex_normalpos
regex_t	fapint_regex_normalamb
regex_t	fapint_regex_timestamp
regex_t	fapint_regex_mice_dstcall
regex_t	fapint_regex_mice_body
regex_t	fapint_regex_mice_amb
regex_t	fapint_regex_comment
regex_t	fapint_regex_phgr
regex_t	fapint_regex_phg
regex_t	fapint_regex_rng
regex_t	fapint_regex_altitude
regex_t	fapint_regex_mes_dst
regex_t	fapint_regex_mes_ack
regex_t	fapint_regex_mes_nack
regex_t	fapint_regex_wx1
regex_t	fapint_regex_wx2
regex_t	fapint_regex_wx3
regex_t	fapint_regex_wx4
regex_t	fapint_regex_wx5
regex_t	fapint_regex_wx_r1
regex_t	fapint_regex_wx_r24
regex_t	fapint_regex_wx_rami
regex_t	fapint_regex_wx_humi
regex_t	fapint_regex_wx_pres
regex_t	fapint_regex_wx_lumi
regex_t	fapint_regex_wx_what
regex_t	fapint_regex_wx_snow
regex_t	fapint_regex_wx_rrc
regex_t	fapint_regex_wx_any
regex_t	fapint_regex_wx_soft
regex_t	fapint_regex_nmea_chksum
regex_t	fapint_regex_nmea_dst
regex_t	fapint_regex_nmea_time
regex_t	fapint_regex_nmea_date
regex_t	fapint_regex_nmea_specou
regex_t	fapint_regex_nmea_fix
regex_t	fapint_regex_nmea_altitude
regex_t	fapint_regex_nmea_flag
regex_t	fapint_regex_nmea_coord
regex_t	fapint_regex_telemetry
regex_t	fapint_regex_peet_splitter
regex_t	fapint_regex_kiss_callsign
regex_t	fapint_regex_kiss_digi
regex_t	fapint_regex_detect_comp
regex_t	fapint_regex_detect_wx
regex_t	fapint_regex_detect_telem
regex_t	fapint_regex_detect_exp
regex_t	fapint_regex_kiss_hdrbdy
regex_t	fapint_regex_hdr_detail
regex_t	fapint_regex_hopcount1
regex_t	fapint_regex_hopcount2
short	fapint_initialized = 0

---

Detailed Description

Implementation of public interface.

Author:

Tapio Aaltonen

Definition in file fap.c.

---

Function Documentation

fap_packet_t* fap_parseaprs	(	char const *	input,
		unsigned int const	input_len,
		short const	is_ax25
	)

The parser.

Resulting packet object will be filled with as much data as possible based on the packet given as parameter. Unfilled fields are set to NULL.

When parsing in AX.25 mode, source callsign and path elements are checked to be strictly compatible with AX.25 specs so that they can be sent into AX.25 network. Destination callsign is always checked this way.

The parser should handle null bytes, newline chars and other badness sometimes seen in packets without crashing as long as input_len is given correctly.

Parameters:

	input	TNC-2 mode APRS packet string.
	input_len	Amount of bytes in input.
	is_ax25	If 1, packet is parsed as AX.25 network packet. If 0, packet is parsed as APRS-IS packet.

Returns:

A packet is always returned, no matter how the parsing went. Use error_code to check how it did. If library is not initialized, returns NULL.

Definition at line 140 of file fap.c.

void fap_explain_error	(	fap_error_code_t const	error,
		char *	buffer
	)

Return human-readable error message for given error code.

Parameters:

	error	Error code from fap_packet_t.
	buffer	Pre-allocated space for the message. Must be at least 60 bytes long.

Definition at line 510 of file fap.c.

void fap_mice_mbits_to_message	(	char const *	bits,
		char *	buffer
	)

Convert mic-e message bits (three numbers 0-2) to a textual message.

Parameters:

	bits	Bits as returned by fap_parseaprs().
	buffer	Pre-allocated space for the message. Must be at least 20 bytes long.

Definition at line 740 of file fap.c.

double fap_distance	(	double	lon0,
		double	lat0,
		double	lon1,
		double	lat1
	)

Calculate distance between given locations.

Returns the distance in kilometers between two locations given in decimal degrees. Arguments are given in order as lon0, lat0, lon1, lat1, east and north positive. The calculation uses the great circle distance, it is not too exact, but good enough for us.

Definition at line 769 of file fap.c.

double fap_direction	(	double	lon0,
		double	lat0,
		double	lon1,
		double	lat1
	)

Calculate direction from first to second location.

Returns the initial great circle direction in degrees from lat0/lon0 to lat1/lon1. Locations are input in decimal degrees, north and east positive.

Definition at line 789 of file fap.c.

int fap_count_digihops

(

fap_packet_t const *

packet

)

Count amount of digihops the packet has gone through.

The number returned is just an educated guess, not absolute truth.

Returns:

Number of digipeated hops or -1 in case of error.

Definition at line 813 of file fap.c.

char* fap_check_ax25_call	(	char const *	input,
		short const	add_ssid0
	)

Check if the callsign is a valid AX.25 callsign.

Parameters:

	input	Callsign to be checked. If SSID is 0, the "-0" suffix can be omitted.
	add_ssid0	If 1, a missing SSID 0 (in practice "-0") is appended to the returned callsign. If 0, valid callsign is returned as is.

Returns:

Given input if it was valid. NULL if the input was not a valid AX.25 address or library is not initialized.

Please note that it's very common to use invalid callsigns on the APRS-IS.

Definition at line 894 of file fap.c.

int fap_kiss_to_tnc2	(	char const *	kissframe,
		unsigned int	kissframe_len,
		char *	tnc2frame,
		unsigned int *	tnc2frame_len,
		unsigned int *	tnc_id
	)

Convert a KISS-frame into a TNC-2 compatible UI-frame.

Non-UI and non-pid-F0 frames are dropped. The KISS-frame to be decoded may or may not have a FEND (0xC0) character at beginning. If there's a FEND in the frame before or at the end, the frame is cutted just before the FEND. Byte unstuffing must not be done before calling this function.

Parameters:

	kissframe	KISS-frame.
	kissframe_len	Amount of bytes in kissframe. Must be less than 512.
	tnc2frame	Result of conversion is stored here. In case of error an error message may be found here.
	tnc2frame_len	Amount of bytes available in tnc2frame is read from here. Amount of bytes written to tnc2frame is written to here upon return.
	tnc_id	TNC ID from the kissframe, usually zero.

Returns:

1 in case of success, 0 when error occured.

Definition at line 964 of file fap.c.

int fap_ax25_to_tnc2	(	char const *	ax25frame,
		unsigned int	ax25frame_len,
		char *	tnc2frame,
		unsigned int *	tnc2frame_len
	)

Convert raw AX.25 frame into TNC-2 compatible UI-frame.

Params and return value work just like similar ones in fap_kiss_to_tnc2().

Definition at line 1063 of file fap.c.

int fap_tnc2_to_kiss	(	char const *	tnc2frame,
		unsigned int	tnc2frame_len,
		unsigned int const	tnc_id,
		char *	kissframe,
		unsigned int *	kissframe_len
	)

Convert a TNC-2 compatible UI-frame into a KISS data frame.

The frame will be complete, i.e. it has byte stuffing done and FEND (0xC0) characters on both ends.

Parameters:

	tnc2frame	TNC-2 frame.
	tnc2frame_len	Amount of bytes in tnc2frame.
	tnc_id	TNC ID to use in KISS frame. When is doubt, use zero.
	kissframe	Where to store the KISS-frame. Be sure to allocate enough space.
	kissframe_len	Amount of bytes stored into kissframe during successfull conversion.

Returns:

1 in case of success, 0 when error occured.

Definition at line 1251 of file fap.c.

int fap_tnc2_to_ax25	(	char const *	tnc2frame,
		unsigned int	tnc2frame_len,
		char *	ax25frame,
		unsigned int *	ax25frame_len
	)

Convert TNC-2 compatible UI-frame into raw AX.25-frame.

Params and return value work just like similar ones in fap_tnc2_to_kiss().

Definition at line 1313 of file fap.c.

void fap_init

(

)

Library initialization.

This must be called once and before anything else when starting to use libfap in your program.

Definition at line 1570 of file fap.c.

void fap_cleanup

(

)

Library cleanup.

This must be called once when closing your app. Make sure that no fap calls are issued after this.

Definition at line 1653 of file fap.c.

void fap_free

(

fap_packet_t *

packet

)

Custom free() for fap_packet_t*.

Use this in place of normal free() when disposing a packet. Will free() all non-NULL fields for you.

Definition at line 1735 of file fap.c.