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
51 enum 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 */
58 enum 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 */
83 struct 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
102 static 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 */
110 enum 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 */
128 struct 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
141 static 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
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