arq.h

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/* HERMES Modem
 *
 * Copyright (C) 2025 Rhizomatica
 * Author: Rafael Diniz <rafael@riseup.net>
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
 
#ifndef ARQ_H_
#define ARQ_H_
 
#define CALLSIGN_MAX_SIZE 16 
 
#define ARQ_BANDWIDTH_NARROW_HZ 500
#define ARQ_BANDWIDTH_FULL_HZ   2300
#define ARQ_BANDWIDTH_TACTICAL_HZ 2750
 
#define RX 0
#define TX 1
 
#define HEADER_SIZE 1
 
#define PACKET_ARQ_CONTROL       0x00
#define PACKET_ARQ_DATA          0x01
#define PACKET_ARQ_CALL          0x02
#define PACKET_BROADCAST_CONTROL 0x03
#define PACKET_BROADCAST_PAYLOAD 0x04
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#include "fsm.h"
#include "arq_events.h"
 
typedef struct
{
    int TRX; // RX (0) or TX (1)
    char my_call_sign[CALLSIGN_MAX_SIZE];
    char src_addr[CALLSIGN_MAX_SIZE], dst_addr[CALLSIGN_MAX_SIZE];
    bool encryption;
    int call_burst_size;
    bool listen;
    int bw;         // configured local bandwidth in Hz
    int session_bw; // negotiated session bandwidth in Hz (0 = not negotiated)
    int retry_slots; // 0 = use compiled default
    size_t frame_size;
    int mode;
} arq_info;
 
typedef enum
{
    ARQ_ACTION_NONE = 0,
    ARQ_ACTION_TX_CONTROL = 1,
    ARQ_ACTION_TX_PAYLOAD = 2,
    ARQ_ACTION_MODE_SWITCH = 3
} arq_action_type_t;
 
typedef struct
{
    arq_action_type_t type;
    int mode;
    size_t frame_size;
} arq_action_t;
 
typedef struct
{
    bool initialized;
    bool connected;
    int trx;
    int tx_backlog_bytes;
    int speed_level;
    int payload_mode;    /* my TX mode (ISS direction)                     */
    int peer_tx_mode;    /* RX decoder mode = peer's TX mode (IRS direction) */
    int control_mode;
    int preferred_rx_mode;
    int preferred_tx_mode;
    uint64_t tx_bytes;
    uint64_t rx_bytes;
} arq_runtime_snapshot_t;
 
extern arq_info arq_conn;
extern fsm_handle arq_fsm;
 
int arq_init(size_t frame_size, int mode);
 
void arq_shutdown();
 
void arq_tick_1hz(void);
 
void arq_post_event(int event);
 
bool arq_is_link_connected(void);
 
int arq_effective_bandwidth_hz(void);
 
int arq_reported_bandwidth_hz(void);
 
bool arq_bandwidth_allows_mode(int mode);
 
int arq_queue_data(const uint8_t *data, size_t len);
 
int arq_get_tx_backlog_bytes(void);
 
int arq_get_speed_level(void);
 
int arq_get_payload_mode(void);
 
int arq_get_control_mode(void);
 
int arq_get_preferred_rx_mode(void);
 
int arq_get_preferred_tx_mode(void);
 
void arq_set_active_modem_mode(int mode, size_t frame_size);
 
bool arq_handle_incoming_connect_frame(uint8_t *data, size_t frame_size);
 
bool arq_handle_incoming_cq_frame(uint8_t *data, size_t frame_size);
 
void arq_notify_cq_tx_started(void);
void arq_notify_cq_tx_complete(void);
 
void arq_handle_incoming_frame(uint8_t *data, size_t frame_size, float rx_snr);
 
void arq_update_link_metrics(int sync, float snr, int rx_status, bool frame_decoded);
 
bool arq_try_dequeue_action(arq_action_t *action);
 
bool arq_wait_dequeue_action(arq_action_t *action, int timeout_ms);
 
bool arq_get_runtime_snapshot(arq_runtime_snapshot_t *snapshot);
 
int arq_submit_tcp_cmd(const arq_cmd_msg_t *cmd);
 
int arq_submit_tcp_payload(const uint8_t *data, size_t len);
 
void clear_connection_data();
 
void reset_arq_info(arq_info *arq_conn);
 
void arq_set_retry_slots(int slots);
 
void call_remote();
 
void callee_accept_connection();
 
#endif