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 */
28 struct 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 */
41 struct tfrc_loss_hist {
42 struct tfrc_loss_interval *ring[LIH_SIZE];
43 u8 counter;
44 u32 i_mean;
45 };
46
47 static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
48 {
49 memset(lh, 0, sizeof(struct tfrc_loss_hist));
50 }
51
52 static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
53 {
54 return lh->counter > 0;
55 }
56
57 static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
58 {
59 return min(lh->counter, (u8)LIH_SIZE);
60 }
61
62 struct tfrc_rx_hist;
63
64 int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
65 u32 (*first_li)(struct sock *), struct sock *);
66 u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
67 void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
68
69 #endif /* _DCCP_LI_HIST_ */
70
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