/* SPDX-License-Identifier: GPL-2.0 */
/*
 * TCP ROCCET congestion control interface
 */
#ifndef __TCP_ROCCET_H
#define __TCP_ROCCET_H 1

#include <linux/math64.h>

/* State in which roccet currently operates */
enum roccet_state {
	LAUNCH,
	ORBITER,
	RTT_PROBE_ENTER,
	RTT_PROBE,
	RTT_PROBE_REFILL,
	DRAIN
};

/* TCP ROCCET struct based on the original BICTCP struct with
 * additions specific to the ROCCET-Algorithm.
 */
struct roccettcp {
	u32 cnt;	/* increase cwnd by 1 after ACKs */
	u32 last_max_cwnd;	/* last maximum snd_cwnd */
	u32 last_cwnd;	/* the last snd_cwnd */
	u32 last_time;	/* time when updated last_cwnd */
	u32 bic_origin_point;	/* origin point of bic function */
	u32 bic_K;	/* time to origin point from the
			 * beginning of the current epoch
			 */
	u32 delay_min;	/* min delay (usec) */
	u32 epoch_start;	/* beginning of an epoch */
	u32 ack_cnt;	/* number of acks */
	u32 tcp_cwnd;	/* estimated tcp cwnd */
	u32 curr_rtt;	/* last sample rtt of current round */

	u32 roccet_last_event_time_us;	/* The last time ROCCET was triggered */
	u32 curr_min_rtt;	/* The current observed minRTT */
	u32 next_min_rtt_probe;	/* Next time to probe the minRTT */
	u32 probe_min_rtt_until;	/* End of minRTT probing period.
					 * Set while in RTT_PROBE states
					 */
	u32 refill_until;	/* End of pipe refill after minRTT probe.
				 * Set while in RTT_PROBE states
				 */
	u32 cwnd_before_min_rtt_probe;	/* cwnd before min RTT probing. */
	u32 curr_srrtt;	/* srRTT calculated based on the latest ACK */
	u32 next_srrtt_check_ts;	/* Next check for srRTT */
	u32 last_rtt;	/* sample rtt of previous round.
			 * Used for jitter calculation
			 */

	u32 interval_snd_seq_start;
	u32 interval_una_seq_start;

	u32 ack_rate_last_rate_time;	/* Timestamp of the last ACK-rate */
	u16 ack_rate_last_rate;	/* Last ACK-rate */
	u16 ack_rate_curr_rate;	/* Current ACK-rate */
	u16 ack_rate_cnt;	/* Used for counting acks */

	enum roccet_state state : 3; /* Current operating state of roccet */
	bool was_idle : 1;	/* Tracks whether the connection was idle
				 * (had no in-flight packets)
				 */
	bool initial_limit_reached: 1;	/* Set to true after the connection
					 * initially gets cwnd-limited
					 */
	bool is_in_initial_launch: 1;	/* true if the connection is in
					 * the initial launch phase.
					 */
	u32 ack_carry_over;	/* Used to carry over leftover acks from
				 * LAUNCH to ORBITER
				 */
};

#endif /* __TCP_ROCCET_H */