aboutsummaryrefslogtreecommitdiff
path: root/net/dccp/ccids/ccid3.h
blob: 7884159937aacf6857904f3e4e678b31c1d0ead3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
/*
 *  net/dccp/ccids/ccid3.h
 *
 *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
 *
 *  An implementation of the DCCP protocol
 *
 *  This code has been developed by the University of Waikato WAND
 *  research group. For further information please see http://www.wand.net.nz/
 *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
 *
 *  This code also uses code from Lulea University, rereleased as GPL by its
 *  authors:
 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
 *
 *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
 *  and to make it work as a loadable module in the DCCP stack written by
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
 *
 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#ifndef _DCCP_CCID3_H_
#define _DCCP_CCID3_H_

#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/tfrc.h>
#include "lib/tfrc.h"
#include "../ccid.h"

/* Two seconds as per RFC 3448 4.2 */
#define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)

/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
#define TFRC_T_MBI		   64

/*
 * The t_delta parameter (RFC 3448, 4.6): delays of less than %USEC_PER_MSEC are
 * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
 * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
 * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
 * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
 */
#if (HZ >= 500)
# define TFRC_T_DELTA		   USEC_PER_MSEC
#else
# define TFRC_T_DELTA		   (USEC_PER_SEC / (2 * HZ))
#warning Coarse CONFIG_HZ resolution -- higher value recommended for TFRC.
#endif

enum ccid3_options {
	TFRC_OPT_LOSS_EVENT_RATE = 192,
	TFRC_OPT_LOSS_INTERVALS	 = 193,
	TFRC_OPT_RECEIVE_RATE	 = 194,
};

/* TFRC sender states */
enum ccid3_hc_tx_states {
	TFRC_SSTATE_NO_SENT = 1,
	TFRC_SSTATE_NO_FBACK,
	TFRC_SSTATE_FBACK,
};

/** struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
 *
 * @x - Current sending rate in 64 * bytes per second
 * @x_recv - Receive rate    in 64 * bytes per second
 * @x_calc - Calculated rate in bytes per second
 * @rtt - Estimate of current round trip time in usecs
 * @p - Current loss event rate (0-1) scaled by 1000000
 * @s - Packet size in bytes
 * @t_rto - Nofeedback Timer setting in usecs
 * @t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs
 * @state - Sender state, one of %ccid3_hc_tx_states
 * @last_win_count - Last window counter sent
 * @t_last_win_count - Timestamp of earliest packet with
 *                     last_win_count value sent
 * @no_feedback_timer - Handle to no feedback timer
 * @t_ld - Time last doubled during slow start
 * @t_nom - Nominal send time of next packet
 * @hist - Packet history
 */
struct ccid3_hc_tx_sock {
	u64				x;
	u64				x_recv;
	u32				x_calc;
	u32				rtt;
	u32				p;
	u32				t_rto;
	u32				t_ipi;
	u16				s;
	enum ccid3_hc_tx_states		state:8;
	u8				last_win_count;
	ktime_t				t_last_win_count;
	struct timer_list		no_feedback_timer;
	ktime_t				t_ld;
	ktime_t				t_nom;
	struct tfrc_tx_hist_entry	*hist;
};

static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
{
    struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
    BUG_ON(hctx == NULL);
    return hctx;
}

/* TFRC receiver states */
enum ccid3_hc_rx_states {
	TFRC_RSTATE_NO_DATA = 1,
	TFRC_RSTATE_DATA,
};

/** struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
 *
 *  @last_counter  -  Tracks window counter (RFC 4342, 8.1)
 *  @state  -  Receiver state, one of %ccid3_hc_rx_states
 *  @bytes_recv  -  Total sum of DCCP payload bytes
 *  @x_recv  -  Receiver estimate of send rate (RFC 3448, sec. 4.3)
 *  @rtt  -  Receiver estimate of RTT
 *  @tstamp_last_feedback  -  Time at which last feedback was sent
 *  @hist  -  Packet history (loss detection + RTT sampling)
 *  @li_hist  -  Loss Interval database
 *  @s  -  Received packet size in bytes
 *  @p_inverse  -  Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
 */
struct ccid3_hc_rx_sock {
	u8				last_counter:4;
	enum ccid3_hc_rx_states		state:8;
	u32				bytes_recv;
	u32				x_recv;
	u32				rtt;
	ktime_t				tstamp_last_feedback;
	struct tfrc_rx_hist		hist;
	struct tfrc_loss_hist		li_hist;
	u16				s;
#define p_inverse			li_hist.i_mean
};

static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
{
    struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
    BUG_ON(hcrx == NULL);
    return hcrx;
}

#endif /* _DCCP_CCID3_H_ */