1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
4 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
5 *
6 *  An implementation of the DCCP protocol
7 *
8 *  This code has been developed by the University of Waikato WAND
9 *  research group. For further information please see https://www.wand.net.nz/
10 *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
11 *
12 *  This code also uses code from Lulea University, rereleased as GPL by its
13 *  authors:
14 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
15 *
16 *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17 *  and to make it work as a loadable module in the DCCP stack written by
18 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
19 *
20 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
21 */
22#ifndef _DCCP_CCID3_H_
23#define _DCCP_CCID3_H_
24
25#include <linux/ktime.h>
26#include <linux/list.h>
27#include <linux/types.h>
28#include <linux/tfrc.h>
29#include "lib/tfrc.h"
30#include "../ccid.h"
31
32/* Two seconds as per RFC 5348, 4.2 */
33#define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)
34
35/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
36#define TFRC_T_MBI		   64
37
38/*
39 * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
40 * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
41 * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
42 * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
43 * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
44 */
45#if (HZ >= 500)
46# define TFRC_T_DELTA		   USEC_PER_MSEC
47#else
48# define TFRC_T_DELTA		   (USEC_PER_SEC / (2 * HZ))
49#endif
50
51enum ccid3_options {
52	TFRC_OPT_LOSS_EVENT_RATE = 192,
53	TFRC_OPT_LOSS_INTERVALS	 = 193,
54	TFRC_OPT_RECEIVE_RATE	 = 194,
55};
56
57/* TFRC sender states */
58enum ccid3_hc_tx_states {
59	TFRC_SSTATE_NO_SENT = 1,
60	TFRC_SSTATE_NO_FBACK,
61	TFRC_SSTATE_FBACK,
62};
63
64/**
65 * struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
66 * @tx_x:		  Current sending rate in 64 * bytes per second
67 * @tx_x_recv:		  Receive rate in 64 * bytes per second
68 * @tx_x_calc:		  Calculated rate in bytes per second
69 * @tx_rtt:		  Estimate of current round trip time in usecs
70 * @tx_p:		  Current loss event rate (0-1) scaled by 1000000
71 * @tx_s:		  Packet size in bytes
72 * @tx_t_rto:		  Nofeedback Timer setting in usecs
73 * @tx_t_ipi:		  Interpacket (send) interval (RFC 3448, 4.6) in usecs
74 * @tx_state:		  Sender state, one of %ccid3_hc_tx_states
75 * @tx_last_win_count:	  Last window counter sent
76 * @tx_t_last_win_count:  Timestamp of earliest packet
77 *			  with last_win_count value sent
78 * @tx_no_feedback_timer: Handle to no feedback timer
79 * @tx_t_ld:		  Time last doubled during slow start
80 * @tx_t_nom:		  Nominal send time of next packet
81 * @tx_hist:		  Packet history
82 */
83struct ccid3_hc_tx_sock {
84	u64				tx_x;
85	u64				tx_x_recv;
86	u32				tx_x_calc;
87	u32				tx_rtt;
88	u32				tx_p;
89	u32				tx_t_rto;
90	u32				tx_t_ipi;
91	u16				tx_s;
92	enum ccid3_hc_tx_states		tx_state:8;
93	u8				tx_last_win_count;
94	ktime_t				tx_t_last_win_count;
95	struct timer_list		tx_no_feedback_timer;
96	struct sock			*sk;
97	ktime_t				tx_t_ld;
98	ktime_t				tx_t_nom;
99	struct tfrc_tx_hist_entry	*tx_hist;
100};
101
102static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
103{
104	struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
105	BUG_ON(hctx == NULL);
106	return hctx;
107}
108
109/* TFRC receiver states */
110enum ccid3_hc_rx_states {
111	TFRC_RSTATE_NO_DATA = 1,
112	TFRC_RSTATE_DATA,
113};
114
115/**
116 * struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
117 * @rx_last_counter:	     Tracks window counter (RFC 4342, 8.1)
118 * @rx_state:		     Receiver state, one of %ccid3_hc_rx_states
119 * @rx_bytes_recv:	     Total sum of DCCP payload bytes
120 * @rx_x_recv:		     Receiver estimate of send rate (RFC 3448, sec. 4.3)
121 * @rx_rtt:		     Receiver estimate of RTT
122 * @rx_tstamp_last_feedback: Time at which last feedback was sent
123 * @rx_hist:		     Packet history (loss detection + RTT sampling)
124 * @rx_li_hist:		     Loss Interval database
125 * @rx_s:		     Received packet size in bytes
126 * @rx_pinv:		     Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
127 */
128struct ccid3_hc_rx_sock {
129	u8				rx_last_counter:4;
130	enum ccid3_hc_rx_states		rx_state:8;
131	u32				rx_bytes_recv;
132	u32				rx_x_recv;
133	u32				rx_rtt;
134	ktime_t				rx_tstamp_last_feedback;
135	struct tfrc_rx_hist		rx_hist;
136	struct tfrc_loss_hist		rx_li_hist;
137	u16				rx_s;
138#define rx_pinv				rx_li_hist.i_mean
139};
140
141static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
142{
143	struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
144	BUG_ON(hcrx == NULL);
145	return hcrx;
146}
147
148#endif /* _DCCP_CCID3_H_ */
149