net/dccp/ccids/ccid3.h

   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_ */