arq_protocol.h File Reference

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

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Data Structures
struct	arq_frame_hdr_t
struct	arq_mode_timing_t

Macros
#define	ARQ_PROTO_VERSION   3 /* v3: 8-byte header, no proto_ver field on wire */
#define	ARQ_HDR_SUBTYPE_IDX   1
#define	ARQ_HDR_FLAGS_IDX   2
#define	ARQ_HDR_SESSION_IDX   3
#define	ARQ_HDR_SEQ_IDX   4
#define	ARQ_HDR_ACK_IDX   5
#define	ARQ_HDR_SNR_IDX   6
#define	ARQ_HDR_DELAY_IDX   7
#define	ARQ_FRAME_HDR_SIZE   8 /* bytes 0-7 inclusive */
#define	ARQ_CONNECT_SESSION_IDX   1
#define	ARQ_CONNECT_PAYLOAD_IDX   2
#define	ARQ_CONNECT_SESSION_MASK   0x7F
#define	ARQ_CONNECT_ACCEPT_FLAG   0x80
#define	ARQ_CONTROL_FRAME_SIZE   14
#define	ARQ_CONNECT_META_SIZE   2 /* framer byte + connect_meta byte */
#define	ARQ_CONNECT_MAX_ENCODED   (ARQ_CONTROL_FRAME_SIZE - ARQ_CONNECT_META_SIZE)
#define	ARQ_FLAG_TURN_REQ   0x80 /* bit 7: sender requests role turn */
#define	ARQ_FLAG_HAS_DATA   0x40 /* bit 6: sender has data queued (IRS→ISS) */
#define	ARQ_FLAG_LEN_HI
#define	ARQ_CHANNEL_GUARD_MS
#define	ARQ_ISS_POST_ACK_GUARD_MS
#define	ARQ_TURN_WAIT_AFTER_ACK_MS
#define	ARQ_ACCEPT_RX_WINDOW_MS
#define	ARQ_ACK_GUARD_S   1 /* extra slack added to retry interval */
#define	ARQ_CALL_RETRY_SLOTS   4 /* CALL retries before giving up */
#define	ARQ_ACCEPT_RETRY_SLOTS   4 /* ACCEPT retries before returning */
#define	ARQ_DATA_RETRY_SLOTS   10 /* DATA retries before disconnect */
#define	ARQ_DISCONNECT_RETRY_SLOTS   2 /* DISCONNECT frame retries */
#define	ARQ_CONNECT_GRACE_SLOTS   2 /* extra wait slots for ACCEPT */
#define	ARQ_CONNECT_BUSY_EXT_S   2 /* busy-extension guard after CALL */
#define	ARQ_KEEPALIVE_INTERVAL_S   20 /* keepalive TX interval */
#define	ARQ_KEEPALIVE_MISS_LIMIT   5 /* missed keepalives before disconnect */
#define	ARQ_TURN_REQ_RETRIES   2
#define	ARQ_MODE_REQ_RETRIES   2
#define	ARQ_MODE_SWITCH_HYST_COUNT   1 /* SNR provides stability gate; 1 = immediate */
#define	ARQ_STARTUP_MAX_S   8 /* DATAC13-only startup window */
#define	ARQ_STARTUP_ACKS_REQUIRED   1
#define	ARQ_PEER_PAYLOAD_HOLD_S   15 /* hold peer payload mode after activity */
#define	ARQ_SNR_HYST_DB   1.0f
#define	ARQ_SNR_MIN_DATAC4_DB   -4.0f /* target MPP SNR (codec2 README) */
#define	ARQ_SNR_MIN_DATAC3_DB   -1.0f
#define	ARQ_SNR_MIN_DATAC1_DB   3.0f
#define	ARQ_BACKLOG_MIN_DATAC3   56
#define	ARQ_BACKLOG_MIN_DATAC1   126
#define	ARQ_BACKLOG_MIN_BIDIR_UPGRADE   48 /* > DATAC4 payload capacity */
#define	ARQ_LADDER_LEVELS   3 /* 0=DATAC4, 1=DATAC3, 2=DATAC1 */
#define	ARQ_LADDER_UP_SUCCESSES   4 /* clean ACKs required to step up */
#define	ARQ_RETRY_DOWNGRADE_THRESHOLD   2 /* consecutive retries to force downgrade */
#define	ARQ_MODE_HOLD_AFTER_DOWNGRADE_S   15 /* hold lower mode after forced downgrade */
#define	ARQ_DATA_LEN_FULL   0

Enumerations
enum	arq_subtype_t {   ARQ_SUBTYPE_CALL = 1 , ARQ_SUBTYPE_ACCEPT = 2 , ARQ_SUBTYPE_ACK = 3 , ARQ_SUBTYPE_DISCONNECT = 4 ,   ARQ_SUBTYPE_DATA = 5 , ARQ_SUBTYPE_KEEPALIVE = 6 , ARQ_SUBTYPE_KEEPALIVE_ACK = 7 , ARQ_SUBTYPE_MODE_REQ = 8 ,   ARQ_SUBTYPE_MODE_ACK = 9 , ARQ_SUBTYPE_TURN_REQ = 10 , ARQ_SUBTYPE_TURN_ACK = 11 }

Functions
int	arq_protocol_encode_hdr (uint8_t *buf, size_t buf_len, const arq_frame_hdr_t *hdr)
	Encode a parsed header into the first ARQ_FRAME_HDR_SIZE bytes of buf.
int	arq_protocol_decode_hdr (const uint8_t *buf, size_t buf_len, arq_frame_hdr_t *hdr)
	Decode the ARQ header from the first bytes of buf.
uint8_t	arq_protocol_encode_snr (float snr_db)
	Encode a floating-point SNR (dB) into the snr_raw wire byte.
float	arq_protocol_decode_snr (uint8_t snr_raw)
	Decode snr_raw wire byte back to float dB.
uint8_t	arq_protocol_encode_ack_delay (uint32_t delay_ms)
	Encode ack_delay_ms to the 8-bit wire value (10ms units, max 2.55s).
uint32_t	arq_protocol_decode_ack_delay (uint8_t raw)
	Decode the 8-bit wire ack_delay to milliseconds.
const arq_mode_timing_t *	arq_protocol_mode_timing (int freedv_mode)
	Look up mode timing entry for a FreeDV mode.
int	arq_protocol_build_ack (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t rx_ack_seq, uint8_t flags, uint8_t snr_raw, uint8_t ack_delay_raw)
	ACK frame.
int	arq_protocol_build_disconnect (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw)
	DISCONNECT frame.
int	arq_protocol_build_keepalive (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw)
	KEEPALIVE frame.
int	arq_protocol_build_keepalive_ack (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw)
	KEEPALIVE_ACK frame.
int	arq_protocol_build_turn_req (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t rx_ack_seq, uint8_t snr_raw)
	TURN_REQ frame.
int	arq_protocol_build_turn_ack (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw)
	TURN_ACK frame.
int	arq_protocol_build_mode_req (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw, int freedv_mode)
	MODE_REQ frame.
int	arq_protocol_build_mode_ack (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t snr_raw, int freedv_mode)
	MODE_ACK frame — accept peer's mode request.
int	arq_protocol_build_data (uint8_t *buf, size_t buf_len, uint8_t session_id, uint8_t tx_seq, uint8_t rx_ack_seq, uint8_t flags, uint8_t snr_raw, uint8_t payload_valid, const uint8_t *payload, size_t payload_len)
	DATA frame — 8-byte header + payload bytes.
int	arq_protocol_build_call (uint8_t *buf, size_t buf_len, uint8_t session_id, const char *src, const char *dst)
	Build a CALL frame.
int	arq_protocol_build_accept (uint8_t *buf, size_t buf_len, uint8_t session_id, const char *src, const char *dst)
	Build an ACCEPT frame.
int	arq_protocol_parse_call (const uint8_t *buf, size_t buf_len, uint8_t *session_id_out, char *src_out, char *dst_out)
	Parse a CALL frame; extract callsigns.
int	arq_protocol_parse_accept (const uint8_t *buf, size_t buf_len, uint8_t *session_id_out, char *src_out, char *dst_out)
	Parse an ACCEPT frame; same layout as CALL.

Variables
const arq_mode_timing_t	arq_mode_table []
const int	arq_mode_table_count

Macro Definition Documentation

ARQ_ACCEPT_RETRY_SLOTS

#define ARQ_ACCEPT_RETRY_SLOTS   4 /* ACCEPT retries before returning */

ARQ_ACCEPT_RX_WINDOW_MS

#define ARQ_ACCEPT_RX_WINDOW_MS

Value:

                                            9000  /* ACCEPTING RX window after ACCEPT TX:
                                            * ISS_guard(900)+DATAC4(5800)+margin(2300)
                                            * Old value 7000 left only ~300ms margin
                                            * and raced with TIMER_RETRY, causing
                                            * 3-4 wasted ACCEPT retries (~28s).    */

ARQ_ACK_GUARD_S

#define ARQ_ACK_GUARD_S   1 /* extra slack added to retry interval */

ARQ_BACKLOG_MIN_BIDIR_UPGRADE

#define ARQ_BACKLOG_MIN_BIDIR_UPGRADE   48 /* > DATAC4 payload capacity */

ARQ_BACKLOG_MIN_DATAC1

#define ARQ_BACKLOG_MIN_DATAC1   126

ARQ_BACKLOG_MIN_DATAC3

#define ARQ_BACKLOG_MIN_DATAC3   56

ARQ_CALL_RETRY_SLOTS

#define ARQ_CALL_RETRY_SLOTS   4 /* CALL retries before giving up */

ARQ_CHANNEL_GUARD_MS

#define ARQ_CHANNEL_GUARD_MS

Value:

                                            700   /* IRS response guard after frame decode.
                                            * OFDM decode fires ~200ms before sender
                                            * PTT-OFF, so effective gap at sender is
                                            * (guard - 200ms) ≈ 500ms.  Radio needs
                                            * ~340ms for TX→RX switch → 160ms margin
                                            * for preamble detection.  At 500ms the
                                            * effective gap was ~300ms, causing ~50%
                                            * ACK loss on DATAC1 (< 340ms switch).  */

ARQ_CONNECT_ACCEPT_FLAG

#define ARQ_CONNECT_ACCEPT_FLAG   0x80

ARQ_CONNECT_BUSY_EXT_S

#define ARQ_CONNECT_BUSY_EXT_S   2 /* busy-extension guard after CALL */

ARQ_CONNECT_GRACE_SLOTS

#define ARQ_CONNECT_GRACE_SLOTS   2 /* extra wait slots for ACCEPT */

ARQ_CONNECT_MAX_ENCODED

#define ARQ_CONNECT_MAX_ENCODED   (ARQ_CONTROL_FRAME_SIZE - ARQ_CONNECT_META_SIZE)

ARQ_CONNECT_META_SIZE

#define ARQ_CONNECT_META_SIZE   2 /* framer byte + connect_meta byte */

ARQ_CONNECT_PAYLOAD_IDX

#define ARQ_CONNECT_PAYLOAD_IDX   2

ARQ_CONNECT_SESSION_IDX

#define ARQ_CONNECT_SESSION_IDX   1

ARQ_CONNECT_SESSION_MASK

#define ARQ_CONNECT_SESSION_MASK   0x7F

ARQ_CONTROL_FRAME_SIZE

#define ARQ_CONTROL_FRAME_SIZE   14

ARQ_DATA_LEN_FULL

#define ARQ_DATA_LEN_FULL   0

ARQ_DATA_RETRY_SLOTS

#define ARQ_DATA_RETRY_SLOTS   10 /* DATA retries before disconnect */

ARQ_DISCONNECT_RETRY_SLOTS

#define ARQ_DISCONNECT_RETRY_SLOTS   2 /* DISCONNECT frame retries */

ARQ_FLAG_HAS_DATA

#define ARQ_FLAG_HAS_DATA   0x40 /* bit 6: sender has data queued (IRS→ISS) */

ARQ_FLAG_LEN_HI

#define ARQ_FLAG_LEN_HI

Value:

                                  0x20  /* bit 5: DATA frames only — payload_valid    *
                                  * field carries bits [7:0] of valid byte     *
                                  * count; this flag carries bit 8, allowing   *
                                  * counts up to 511 (needed for DATAC1 which  *
                                  * has 502-byte payloads).                    */

ARQ_FLAG_TURN_REQ

#define ARQ_FLAG_TURN_REQ   0x80 /* bit 7: sender requests role turn */

ARQ_FRAME_HDR_SIZE

#define ARQ_FRAME_HDR_SIZE   8 /* bytes 0-7 inclusive */

ARQ_HDR_ACK_IDX

#define ARQ_HDR_ACK_IDX   5

ARQ_HDR_DELAY_IDX

#define ARQ_HDR_DELAY_IDX   7

ARQ_HDR_FLAGS_IDX

#define ARQ_HDR_FLAGS_IDX   2

ARQ_HDR_SEQ_IDX

#define ARQ_HDR_SEQ_IDX   4

ARQ_HDR_SESSION_IDX

#define ARQ_HDR_SESSION_IDX   3

ARQ_HDR_SNR_IDX

#define ARQ_HDR_SNR_IDX   6

ARQ_HDR_SUBTYPE_IDX

#define ARQ_HDR_SUBTYPE_IDX   1

ARQ_ISS_POST_ACK_GUARD_MS

#define ARQ_ISS_POST_ACK_GUARD_MS

Value:

                                            900   /* ISS guard before resuming DATA TX
                                            * after receiving an ACK from the IRS.
                                            * Larger than ARQ_CHANNEL_GUARD_MS:
                                            * ack_rx fires ~168ms before IRS PTT-OFF,
                                            * so the effective gap at IRS is only
                                            * (guard + 100ms head) - 168ms.
                                            * At 500ms: gap=432ms, too tight for
                                            * DATAC1 re-sync after IRS ACK TX.
                                            * At 900ms: gap=832ms — 492ms of clear
                                            * air before the DATAC1 preamble. */

ARQ_KEEPALIVE_INTERVAL_S

#define ARQ_KEEPALIVE_INTERVAL_S   20 /* keepalive TX interval */

ARQ_KEEPALIVE_MISS_LIMIT

#define ARQ_KEEPALIVE_MISS_LIMIT   5 /* missed keepalives before disconnect */

ARQ_LADDER_LEVELS

#define ARQ_LADDER_LEVELS   3 /* 0=DATAC4, 1=DATAC3, 2=DATAC1 */

ARQ_LADDER_UP_SUCCESSES

#define ARQ_LADDER_UP_SUCCESSES   4 /* clean ACKs required to step up */

ARQ_MODE_HOLD_AFTER_DOWNGRADE_S

#define ARQ_MODE_HOLD_AFTER_DOWNGRADE_S   15 /* hold lower mode after forced downgrade */

ARQ_MODE_REQ_RETRIES

#define ARQ_MODE_REQ_RETRIES   2

ARQ_MODE_SWITCH_HYST_COUNT

#define ARQ_MODE_SWITCH_HYST_COUNT   1 /* SNR provides stability gate; 1 = immediate */

ARQ_PEER_PAYLOAD_HOLD_S

#define ARQ_PEER_PAYLOAD_HOLD_S   15 /* hold peer payload mode after activity */

ARQ_PROTO_VERSION

#define ARQ_PROTO_VERSION   3 /* v3: 8-byte header, no proto_ver field on wire */

ARQ_RETRY_DOWNGRADE_THRESHOLD

#define ARQ_RETRY_DOWNGRADE_THRESHOLD   2 /* consecutive retries to force downgrade */

ARQ_SNR_HYST_DB

#define ARQ_SNR_HYST_DB   1.0f

ARQ_SNR_MIN_DATAC1_DB

#define ARQ_SNR_MIN_DATAC1_DB   3.0f

ARQ_SNR_MIN_DATAC3_DB

#define ARQ_SNR_MIN_DATAC3_DB   -1.0f

ARQ_SNR_MIN_DATAC4_DB

#define ARQ_SNR_MIN_DATAC4_DB   -4.0f /* target MPP SNR (codec2 README) */

ARQ_STARTUP_ACKS_REQUIRED

#define ARQ_STARTUP_ACKS_REQUIRED   1

ARQ_STARTUP_MAX_S

#define ARQ_STARTUP_MAX_S   8 /* DATAC13-only startup window */

ARQ_TURN_REQ_RETRIES

#define ARQ_TURN_REQ_RETRIES   2

ARQ_TURN_WAIT_AFTER_ACK_MS

#define ARQ_TURN_WAIT_AFTER_ACK_MS

Value:

                                            3500  /* IRS post-ACK wait before TURN_REQ:
                                            * ISS guard(900ms)+frame(2510ms)+margin */

Enumeration Type Documentation

arq_subtype_t

enum arq_subtype_t

Enumerator
ARQ_SUBTYPE_CALL
ARQ_SUBTYPE_ACCEPT
ARQ_SUBTYPE_ACK
ARQ_SUBTYPE_DISCONNECT
ARQ_SUBTYPE_DATA
ARQ_SUBTYPE_KEEPALIVE
ARQ_SUBTYPE_KEEPALIVE_ACK
ARQ_SUBTYPE_MODE_REQ
ARQ_SUBTYPE_MODE_ACK
ARQ_SUBTYPE_TURN_REQ
ARQ_SUBTYPE_TURN_ACK

Function Documentation

arq_protocol_build_accept()

int arq_protocol_build_accept	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		const char *	src,
		const char *	dst
	)

Build an ACCEPT frame.

Parameters

buf	Output buffer (caller-provided).
buf_len	Size of buf in bytes.
session_id	ARQ session identifier.
src	Local callsign.
dst	Remote callsign.

arq_protocol_build_ack()

int arq_protocol_build_ack	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	rx_ack_seq,
		uint8_t	flags,
		uint8_t	snr_raw,
		uint8_t	ack_delay_raw
	)

ACK frame.

flags = ARQ_FLAG_HAS_DATA when IRS has pending TX data.

arq_protocol_build_call()

int arq_protocol_build_call	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		const char *	src,
		const char *	dst
	)

Build a CALL frame.

Parameters

buf	Output buffer (caller-provided).
buf_len	Size of buf in bytes.
session_id	ARQ session identifier.
src	Local callsign.
dst	Remote callsign.

Returns

Total frame bytes (ARQ_CONTROL_FRAME_SIZE = 14) on success, -1 on error.

arq_protocol_build_data()

int arq_protocol_build_data	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	tx_seq,
		uint8_t	rx_ack_seq,
		uint8_t	flags,
		uint8_t	snr_raw,
		uint8_t	payload_valid,
		const uint8_t *	payload,
		size_t	payload_len
	)

DATA frame — 8-byte header + payload bytes.

Parameters

buf	Output buffer (caller-provided).
buf_len	Size of buf in bytes.
session_id	ARQ session identifier.
tx_seq	TX sequence number.
rx_ack_seq	Last seq received from peer (piggybacked ACK).
flags	ARQ_FLAG_TURN_REQ | ARQ_FLAG_HAS_DATA (bitmask).
snr_raw	Local SNR encoded for wire.
payload_valid	Number of valid bytes in the payload slot.
payload	Payload bytes (must be <= buf_len - ARQ_FRAME_HDR_SIZE).
payload_len	Number of payload bytes.

arq_protocol_build_disconnect()

int arq_protocol_build_disconnect	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw
	)

DISCONNECT frame.

arq_protocol_build_keepalive()

int arq_protocol_build_keepalive	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw
	)

KEEPALIVE frame.

arq_protocol_build_keepalive_ack()

int arq_protocol_build_keepalive_ack	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw
	)

KEEPALIVE_ACK frame.

arq_protocol_build_mode_ack()

int arq_protocol_build_mode_ack	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw,
		int	freedv_mode
	)

MODE_ACK frame — accept peer's mode request.

arq_protocol_build_mode_req()

int arq_protocol_build_mode_req	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw,
		int	freedv_mode
	)

MODE_REQ frame.

Parameters

buf	Output buffer (caller-provided).
buf_len	Size of buf in bytes.
session_id	ARQ session identifier.
snr_raw	Local SNR encoded for wire.
freedv_mode	Requested payload FreeDV mode (FREEDV_MODE_DATAC*).

arq_protocol_build_turn_ack()

int arq_protocol_build_turn_ack	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	snr_raw
	)

TURN_ACK frame.

arq_protocol_build_turn_req()

int arq_protocol_build_turn_req	(	uint8_t *	buf,
		size_t	buf_len,
		uint8_t	session_id,
		uint8_t	rx_ack_seq,
		uint8_t	snr_raw
	)

TURN_REQ frame.

Parameters

buf	Output buffer (caller-provided).
buf_len	Size of buf in bytes.
session_id	ARQ session identifier.
rx_ack_seq	Last seq received from current ISS (so ISS can flush pending retries).
snr_raw	Local SNR encoded for wire.

arq_protocol_decode_ack_delay()

uint32_t arq_protocol_decode_ack_delay

(

uint8_t

raw

)

Decode the 8-bit wire ack_delay to milliseconds.

arq_protocol_decode_hdr()

int arq_protocol_decode_hdr	(	const uint8_t *	buf,
		size_t	buf_len,
		arq_frame_hdr_t *	hdr
	)

Decode the ARQ header from the first bytes of buf.

Returns

0 on success, -1 if buf too short.

arq_protocol_decode_snr()

float arq_protocol_decode_snr

(

uint8_t

snr_raw

)

Decode snr_raw wire byte back to float dB.

Returns

SNR in dB, or 0.0f if snr_raw == 0 (unknown).

arq_protocol_encode_ack_delay()

uint8_t arq_protocol_encode_ack_delay

(

uint32_t

delay_ms

)

Encode ack_delay_ms to the 8-bit wire value (10ms units, max 2.55s).

arq_protocol_encode_hdr()

int arq_protocol_encode_hdr	(	uint8_t *	buf,
		size_t	buf_len,
		const arq_frame_hdr_t *	hdr
	)

Encode a parsed header into the first ARQ_FRAME_HDR_SIZE bytes of buf.

Returns

0 on success, -1 if buf_len < ARQ_FRAME_HDR_SIZE.

arq_protocol_encode_snr()

uint8_t arq_protocol_encode_snr

(

float

snr_db

)

Encode a floating-point SNR (dB) into the snr_raw wire byte.

Returns

Encoded byte (0 if snr_db is out of range or unknown).

arq_protocol_mode_timing()

const arq_mode_timing_t * arq_protocol_mode_timing

(

int

freedv_mode

)

Look up mode timing entry for a FreeDV mode.

Returns

Pointer to timing entry, or NULL if mode is unknown.

arq_protocol_parse_accept()

int arq_protocol_parse_accept	(	const uint8_t *	buf,
		size_t	buf_len,
		uint8_t *	session_id_out,
		char *	src_out,
		char *	dst_out
	)

Parse an ACCEPT frame; same layout as CALL.

arq_protocol_parse_call()

int arq_protocol_parse_call	(	const uint8_t *	buf,
		size_t	buf_len,
		uint8_t *	session_id_out,
		char *	src_out,
		char *	dst_out
	)

Parse a CALL frame; extract callsigns.

Parameters

buf	Input frame buffer.
buf_len	Size of buf in bytes.
session_id_out	Receives the session_id byte.
src_out	Buffer for local (transmitting) callsign, CALLSIGN_MAX_SIZE bytes.
dst_out	Buffer for remote callsign, CALLSIGN_MAX_SIZE bytes.

Returns

0 on success, -1 on parse error.

Variable Documentation

arq_mode_table

const arq_mode_timing_t arq_mode_table[]

extern

arq_mode_table_count

const int arq_mode_table_count

extern