/*-------------------------------------------------------------------
*
* Name: ax25_pad.h
*
* Purpose: Header file for using ax25_pad.c
*
*------------------------------------------------------------------*/
#ifndef AX25_PAD_H
#define AX25_PAD_H 1
#define AX25_MAX_REPEATERS 8
#define AX25_MIN_ADDRS 2 /* Destinatin & Source. */
#define AX25_MAX_ADDRS 10 /* Destination, Source, 8 digipeaters. */
#define AX25_DESTINATION 0 /* Address positions in frame. */
#define AX25_SOURCE 1
#define AX25_REPEATER_1 2
#define AX25_REPEATER_2 3
#define AX25_REPEATER_3 4
#define AX25_REPEATER_4 5
#define AX25_REPEATER_5 6
#define AX25_REPEATER_6 7
#define AX25_REPEATER_7 8
#define AX25_REPEATER_8 9
#define AX25_MAX_ADDR_LEN 12 /* In theory, you would expect the maximum length */
/* to be 6 letters, dash, 2 digits, and nul for a */
/* total of 10. However, object labels can be 10 */
/* characters so throw in a couple extra bytes */
/* to be safe. */
#define AX25_MIN_INFO_LEN 0 /* Previously 1 when considering only APRS. */
#define AX25_MAX_INFO_LEN 2048 /* Maximum size for APRS. */
/* AX.25 starts out with 256 as the default max */
/* length but the end stations can negotiate */
/* something different. */
/* version 0.8: Change from 256 to 2028 to */
/* handle the larger paclen for Linux AX25. */
/* These don't include the 2 bytes for the */
/* HDLC frame FCS. */
/*
* Previously, for APRS only.
* #define AX25_MIN_PACKET_LEN ( 2 * 7 + 2 + AX25_MIN_INFO_LEN)
* #define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + AX25_MAX_INFO_LEN)
*/
/* The more general case. */
/* An AX.25 frame can have a control byte and no protocol. */
#define AX25_MIN_PACKET_LEN ( 2 * 7 + 1 )
#define AX25_MAX_PACKET_LEN ( AX25_MAX_ADDRS * 7 + 2 + 3 + AX25_MAX_INFO_LEN)
/*
* packet_t is a pointer to a packet object.
*
* The actual implementation is not visible outside ax25_pad.c.
*/
#define AX25_UI_FRAME 3 /* Control field value. */
#define AX25_PID_NO_LAYER_3 0xf0 /* protocol ID used for APRS */
#define AX25_PID_SEGMENTATION_FRAGMENT 0x08
#define AX25_PID_ESCAPE_CHARACTER 0xff
#ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */
struct packet_s {
int magic1; /* for error checking. */
int seq; /* unique sequence number for debugging. */
double release_time; /* Time stamp in format returned by dtime_now(). */
/* When to release from the SATgate mode delay queue. */
#define MAGIC 0x41583235
struct packet_s *nextp; /* Pointer to next in queue. */
int num_addr; /* Number of addresses in frame. */
/* Range of AX25_MIN_ADDRS .. AX25_MAX_ADDRS for AX.25. */
/* It will be 0 if it doesn't look like AX.25. */
/* -1 is used temporarily at allocation to mean */
/* not determined yet. */
/*
* The 7th octet of each address contains:
*
* Bits: H R R SSID 0
*
* H for digipeaters set to 0 intially.
* Changed to 1 when position has been used.
*
* for source & destination it is called
* command/response. Normally both 1 for APRS.
* They should be opposites for connected mode.
*
* R R Reserved. Normally set to 1 1.
*
* SSID Substation ID. Range of 0 - 15.
*
* 0 Usually 0 but 1 for last address.
*/
#define SSID_H_MASK 0x80
#define SSID_H_SHIFT 7
#define SSID_RR_MASK 0x60
#define SSID_RR_SHIFT 5
#define SSID_SSID_MASK 0x1e
#define SSID_SSID_SHIFT 1
#define SSID_LAST_MASK 0x01
int frame_len; /* Frame length without CRC. */
int modulo; /* I & S frames have sequence numbers of either 3 bits (modulo 8) */
/* or 7 bits (modulo 128). This is conveyed by either 1 or 2 */
/* control bytes. Unfortunately, we can't determine this by looking */
/* at an isolated frame. We need to know about the context. If we */
/* are part of the conversation, we would know. But if we are */
/* just listening to others, this would be more difficult to determine. */
/* For U frames: set to 0 - not applicable */
/* For I & S frames: 8 or 128 if known. 0 if unknown. */
unsigned char frame_data[AX25_MAX_PACKET_LEN+1];
/* Raw frame contents, without the CRC. */
int magic2; /* Will get stomped on if above overflows. */
};
#else /* Public view. */
struct packet_s {
int secret;
};
#endif
typedef struct packet_s *packet_t;
typedef enum cmdres_e { cr_00 = 2, cr_cmd = 1, cr_res = 0, cr_11 = 3 } cmdres_t;
extern packet_t ax25_new (void);
#ifdef AX25_PAD_C /* Keep this hidden - implementation could change. */
/*
* APRS always has one control octet of 0x03 but the more
* general AX.25 case is one or two control bytes depending on
* whether "modulo 128 operation" is in effect.
*/
//#define DEBUGX 1
static inline int ax25_get_control_offset (packet_t this_p)
{
return (this_p->num_addr*7);
}
static inline int ax25_get_num_control (packet_t this_p)
{
int c;
c = this_p->frame_data[ax25_get_control_offset(this_p)];
if ( (c & 0x01) == 0 ) { /* I xxxx xxx0 */
#if DEBUGX
dw_printf ("ax25_get_num_control, %02x is I frame, returns %d\n", c, (this_p->modulo == 128) ? 2 : 1);
#endif
return ((this_p->modulo == 128) ? 2 : 1);
}
if ( (c & 0x03) == 1 ) { /* S xxxx xx01 */
#if DEBUGX
dw_printf ("ax25_get_num_control, %02x is S frame, returns %d\n", c, (this_p->modulo == 128) ? 2 : 1);
#endif
return ((this_p->modulo == 128) ? 2 : 1);
}
#if DEBUGX
dw_printf ("ax25_get_num_control, %02x is U frame, always returns 1.\n", c);
#endif
return (1); /* U xxxx xx11 */
}
/*
* APRS always has one protocol octet of 0xF0 meaning no level 3
* protocol but the more general case is 0, 1 or 2 protocol ID octets.
*/
static inline int ax25_get_pid_offset (packet_t this_p)
{
return (ax25_get_control_offset (this_p) + ax25_get_num_control(this_p));
}
static int ax25_get_num_pid (packet_t this_p)
{
int c;
int pid;
c = this_p->frame_data[ax25_get_control_offset(this_p)];
if ( (c & 0x01) == 0 || /* I xxxx xxx0 */
c == 0x03 || c == 0x13) { /* UI 000x 0011 */
pid = this_p->frame_data[ax25_get_pid_offset(this_p)];
#if DEBUGX
dw_printf ("ax25_get_num_pid, %02x is I or UI frame, pid = %02x, returns %d\n", c, pid, (pid==AX25_PID_ESCAPE_CHARACTER) ? 2 : 1);
#endif
if (pid == AX25_PID_ESCAPE_CHARACTER) {
return (2); /* pid 1111 1111 means another follows. */
}
return (1);
}
#if DEBUGX
dw_printf ("ax25_get_num_pid, %02x is neither I nor UI frame, returns 0\n", c);
#endif
return (0);
}
/*
* AX.25 has info field for 5 frame types depending on the control field.
*
* xxxx xxx0 I
* 000x 0011 UI (which includes APRS)
* 101x 1111 XID
* 111x 0011 TEST
* 100x 0111 FRMR
*
* APRS always has an Information field with at least one octet for the Data Type Indicator.
*/
static inline int ax25_get_info_offset (packet_t this_p)
{
int offset = ax25_get_control_offset (this_p) + ax25_get_num_control(this_p) + ax25_get_num_pid(this_p);
#if DEBUGX
dw_printf ("ax25_get_info_offset, returns %d\n", offset);
#endif
return (offset);
}
static inline int ax25_get_num_info (packet_t this_p)
{
int len;
/* assuming AX.25 frame. */
len = this_p->frame_len - this_p->num_addr * 7 - ax25_get_num_control(this_p) - ax25_get_num_pid(this_p);
if (len < 0) {
len = 0; /* print error? */
}
return (len);
}
#endif
typedef enum ax25_modulo_e { modulo_unknown = 0, modulo_8 = 8, modulo_128 = 128 } ax25_modulo_t;
typedef enum ax25_frame_type_e {
frame_type_I = 0, // Information
frame_type_S_RR, // Receive Ready - System Ready To Receive
frame_type_S_RNR, // Receive Not Ready - TNC Buffer Full
frame_type_S_REJ, // Reject Frame - Out of Sequence or Duplicate
frame_type_S_SREJ, // Selective Reject - Request single frame repeat
frame_type_U_SABME, // Set Async Balanced Mode, Extended
frame_type_U_SABM, // Set Async Balanced Mode
frame_type_U_DISC, // Disconnect
frame_type_U_DM, // Disconnect Mode
frame_type_U_UA, // Unnumbered Acknowledge
frame_type_U_FRMR, // Frame Reject
frame_type_U_UI, // Unnumbered Information
frame_type_U_XID, // Exchange Identification
frame_type_U_TEST, // Test
frame_type_U, // other Unnumbered, not used by AX.25.
frame_not_AX25 // Could not get control byte from frame.
// This must be last because value plus 1 is
// for the size of an array.
} ax25_frame_type_t;
/*
* Originally this was a single number.
* Let's try something new in version 1.2.
* Also collect AGC values from the mark and space filters.
*/
typedef struct alevel_s {
int rec;
int mark;
int space;
//float ms_ratio; // TODO: take out after temporary investigation.
} alevel_t;
#ifndef AXTEST
// TODO: remove this?
#define AX25MEMDEBUG 1
#endif
#if AX25MEMDEBUG // to investigate a memory leak problem
extern void ax25memdebug_set(void);
extern int ax25memdebug_get (void);
extern int ax25memdebug_seq (packet_t this_p);
extern packet_t ax25_from_text_debug (char *monitor, int strict, char *src_file, int src_line);
#define ax25_from_text(m,s) ax25_from_text_debug(m,s,__FILE__,__LINE__)
extern packet_t ax25_from_frame_debug (unsigned char *data, int len, alevel_t alevel, char *src_file, int src_line);
#define ax25_from_frame(d,l,a) ax25_from_frame_debug(d,l,a,__FILE__,__LINE__);
extern packet_t ax25_dup_debug (packet_t copy_from, char *src_file, int src_line);
#define ax25_dup(p) ax25_dup_debug(p,__FILE__,__LINE__);
extern void ax25_delete_debug (packet_t pp, char *src_file, int src_line);
#define ax25_delete(p) ax25_delete_debug(p,__FILE__,__LINE__);
#else
extern packet_t ax25_from_text (char *monitor, int strict);
extern packet_t ax25_from_frame (unsigned char *data, int len, alevel_t alevel);
extern packet_t ax25_dup (packet_t copy_from);
extern void ax25_delete (packet_t pp);
#endif
extern int ax25_parse_addr (int position, char *in_addr, int strict, char *out_addr, int *out_ssid, int *out_heard);
extern int ax25_check_addresses (packet_t pp);
extern packet_t ax25_unwrap_third_party (packet_t from_pp);
extern void ax25_set_addr (packet_t pp, int, char *);
extern void ax25_insert_addr (packet_t this_p, int n, char *ad);
extern void ax25_remove_addr (packet_t this_p, int n);
extern int ax25_get_num_addr (packet_t pp);
extern int ax25_get_num_repeaters (packet_t this_p);
extern void ax25_get_addr_with_ssid (packet_t pp, int n, char *station);
extern void ax25_get_addr_no_ssid (packet_t pp, int n, char *station);
extern int ax25_get_ssid (packet_t pp, int n);
extern void ax25_set_ssid (packet_t this_p, int n, int ssid);
extern int ax25_get_h (packet_t pp, int n);
extern void ax25_set_h (packet_t pp, int n);
extern int ax25_get_heard(packet_t this_p);
extern int ax25_get_first_not_repeated(packet_t pp);
extern int ax25_get_rr (packet_t this_p, int n);
extern int ax25_get_info (packet_t pp, unsigned char **paddr);
extern int ax25_cut_at_crlf (packet_t this_p);
extern void ax25_set_nextp (packet_t this_p, packet_t next_p);
extern int ax25_get_dti (packet_t this_p);
extern packet_t ax25_get_nextp (packet_t this_p);
extern void ax25_set_release_time (packet_t this_p, double release_time);
extern double ax25_get_release_time (packet_t this_p);
extern void ax25_set_modulo (packet_t this_p, int modulo);
extern void ax25_format_addrs (packet_t pp, char *);
extern void ax25_format_via_path (packet_t this_p, char *result, size_t result_size);
extern int ax25_pack (packet_t pp, unsigned char result[AX25_MAX_PACKET_LEN]);
extern ax25_frame_type_t ax25_frame_type (packet_t this_p, cmdres_t *cr, char *desc, int *pf, int *nr, int *ns);
extern void ax25_hex_dump (packet_t this_p);
extern int ax25_is_aprs (packet_t pp);
extern int ax25_is_null_frame (packet_t this_p);
extern int ax25_get_control (packet_t this_p);
extern int ax25_get_c2 (packet_t this_p);
extern int ax25_get_pid (packet_t this_p);
extern int ax25_get_frame_len (packet_t this_p);
extern unsigned short ax25_dedupe_crc (packet_t pp);
extern unsigned short ax25_m_m_crc (packet_t pp);
extern void ax25_safe_print (char *, int, int ascii_only);
#define AX25_ALEVEL_TO_TEXT_SIZE 32 // overkill but safe.
extern int ax25_alevel_to_text (alevel_t alevel, char text[AX25_ALEVEL_TO_TEXT_SIZE]);
#endif /* AX25_PAD_H */
/* end ax25_pad.h */