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 
tfrc_lh_init(struct tfrc_loss_hist * lh)47 static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
48 {
49 	memset(lh, 0, sizeof(struct tfrc_loss_hist));
50 }
51 
tfrc_lh_is_initialised(struct tfrc_loss_hist * lh)52 static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
53 {
54 	return lh->counter > 0;
55 }
56 
tfrc_lh_length(struct tfrc_loss_hist * lh)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