1/* SPDX-License-Identifier: GPL-2.0-or-later */
2#ifndef _DCCP_LI_HIST_
3#define _DCCP_LI_HIST_
4/*
5 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
6 *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
7 *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
8 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
9 */
10#include <linux/ktime.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13
14/*
15 * Number of loss intervals (RFC 4342, 8.6.1). The history size is one more than
16 * NINTERVAL, since the `open' interval I_0 is always stored as the first entry.
17 */
18#define NINTERVAL	8
19#define LIH_SIZE	(NINTERVAL + 1)
20
21/**
22 *  tfrc_loss_interval  -  Loss history record for TFRC-based protocols
23 *  @li_seqno:		Highest received seqno before the start of loss
24 *  @li_ccval:		The CCVal belonging to @li_seqno
25 *  @li_is_closed:	Whether @li_seqno is older than 1 RTT
26 *  @li_length:		Loss interval sequence length
27 */
28struct tfrc_loss_interval {
29	u64		 li_seqno:48,
30			 li_ccval:4,
31			 li_is_closed:1;
32	u32		 li_length;
33};
34
35/**
36 *  tfrc_loss_hist  -  Loss record database
37 *  @ring:	Circular queue managed in LIFO manner
38 *  @counter:	Current count of entries (can be more than %LIH_SIZE)
39 *  @i_mean:	Current Average Loss Interval [RFC 3448, 5.4]
40 */
41struct tfrc_loss_hist {
42	struct tfrc_loss_interval	*ring[LIH_SIZE];
43	u8				counter;
44	u32				i_mean;
45};
46
47static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
48{
49	memset(lh, 0, sizeof(struct tfrc_loss_hist));
50}
51
52static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
53{
54	return lh->counter > 0;
55}
56
57static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
58{
59	return min(lh->counter, (u8)LIH_SIZE);
60}
61
62struct tfrc_rx_hist;
63
64int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
65			 u32 (*first_li)(struct sock *), struct sock *);
66u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
67void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
68
69#endif /* _DCCP_LI_HIST_ */
70