net/dccp/ccids/ccid3.h

   1 /*
   2  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
   3  *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   4  *
   5  *  An implementation of the DCCP protocol
   6  *
   7  *  This code has been developed by the University of Waikato WAND
   8  *  research group. For further information please see http://www.wand.net.nz/
   9  *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
  10  *
  11  *  This code also uses code from Lulea University, rereleased as GPL by its
  12  *  authors:
  13  *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
  14  *
  15  *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
  16  *  and to make it work as a loadable module in the DCCP stack written by
  17  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
  18  *
  19  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  20  *
  21  *  This program is free software; you can redistribute it and/or modify
  22  *  it under the terms of the GNU General Public License as published by
  23  *  the Free Software Foundation; either version 2 of the License, or
  24  *  (at your option) any later version.
  25  *
  26  *  This program is distributed in the hope that it will be useful,
  27  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  *  GNU General Public License for more details.
  30  *
  31  *  You should have received a copy of the GNU General Public License
  32  *  along with this program; if not, write to the Free Software
  33  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  34  */
  35 #ifndef _DCCP_CCID3_H_
  36 #define _DCCP_CCID3_H_
  37
  38 #include <linux/ktime.h>
  39 #include <linux/list.h>
  40 #include <linux/types.h>
  41 #include <linux/tfrc.h>
  42 #include "lib/tfrc.h"
  43 #include "../ccid.h"
  44
  45 /* Two seconds as per RFC 5348, 4.2 */
  46 #define TFRC_INITIAL_TIMEOUT       (2 * USEC_PER_SEC)
  47
  48 /* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
  49 #define TFRC_T_MBI                 64
  50
  51 /*
  52  * The t_delta parameter (RFC 5348, 8.3): delays of less than %USEC_PER_MSEC are
  53  * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
  54  * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
  55  * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
  56  * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
  57  */
  58 #if (HZ >= 500)
  59 # define TFRC_T_DELTA              USEC_PER_MSEC
  60 #else
  61 # define TFRC_T_DELTA              (USEC_PER_SEC / (2 * HZ))
  62 #endif
  63
  64 enum ccid3_options {
  65         TFRC_OPT_LOSS_EVENT_RATE = 192,
  66         TFRC_OPT_LOSS_INTERVALS  = 193,
  67         TFRC_OPT_RECEIVE_RATE    = 194,
  68 };
  69
  70 /* TFRC sender states */
  71 enum ccid3_hc_tx_states {
  72         TFRC_SSTATE_NO_SENT = 1,
  73         TFRC_SSTATE_NO_FBACK,
  74         TFRC_SSTATE_FBACK,
  75 };
  76
  77 /**
  78  * struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
  79  * @tx_x:                 Current sending rate in 64 * bytes per second
  80  * @tx_x_recv:            Receive rate in 64 * bytes per second
  81  * @tx_x_calc:            Calculated rate in bytes per second
  82  * @tx_rtt:               Estimate of current round trip time in usecs
  83  * @tx_p:                 Current loss event rate (0-1) scaled by 1000000
  84  * @tx_s:                 Packet size in bytes
  85  * @tx_t_rto:             Nofeedback Timer setting in usecs
  86  * @tx_t_ipi:             Interpacket (send) interval (RFC 3448, 4.6) in usecs
  87  * @tx_state:             Sender state, one of %ccid3_hc_tx_states
  88  * @tx_last_win_count:    Last window counter sent
  89  * @tx_t_last_win_count:  Timestamp of earliest packet
  90  *                        with last_win_count value sent
  91  * @tx_no_feedback_timer: Handle to no feedback timer
  92  * @tx_t_ld:              Time last doubled during slow start
  93  * @tx_t_nom:             Nominal send time of next packet
  94  * @tx_hist:              Packet history
  95  */
  96 struct ccid3_hc_tx_sock {
  97         u64                             tx_x;
  98         u64                             tx_x_recv;
  99         u32                             tx_x_calc;
 100         u32                             tx_rtt;
 101         u32                             tx_p;
 102         u32                             tx_t_rto;
 103         u32                             tx_t_ipi;
 104         u16                             tx_s;
 105         enum ccid3_hc_tx_states         tx_state:8;
 106         u8                              tx_last_win_count;
 107         ktime_t                         tx_t_last_win_count;
 108         struct timer_list               tx_no_feedback_timer;
 109         ktime_t                         tx_t_ld;
 110         ktime_t                         tx_t_nom;
 111         struct tfrc_tx_hist_entry       *tx_hist;
 112 };
 113
 114 static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
 115 {
 116         struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
 117         BUG_ON(hctx == NULL);
 118         return hctx;
 119 }
 120
 121 /* TFRC receiver states */
 122 enum ccid3_hc_rx_states {
 123         TFRC_RSTATE_NO_DATA = 1,
 124         TFRC_RSTATE_DATA,
 125 };
 126
 127 /**
 128  * struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
 129  * @rx_last_counter:         Tracks window counter (RFC 4342, 8.1)
 130  * @rx_state:                Receiver state, one of %ccid3_hc_rx_states
 131  * @rx_bytes_recv:           Total sum of DCCP payload bytes
 132  * @rx_x_recv:               Receiver estimate of send rate (RFC 3448, sec. 4.3)
 133  * @rx_rtt:                  Receiver estimate of RTT
 134  * @rx_tstamp_last_feedback: Time at which last feedback was sent
 135  * @rx_hist:                 Packet history (loss detection + RTT sampling)
 136  * @rx_li_hist:              Loss Interval database
 137  * @rx_s:                    Received packet size in bytes
 138  * @rx_pinv:                 Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
 139  */
 140 struct ccid3_hc_rx_sock {
 141         u8                              rx_last_counter:4;
 142         enum ccid3_hc_rx_states         rx_state:8;
 143         u32                             rx_bytes_recv;
 144         u32                             rx_x_recv;
 145         u32                             rx_rtt;
 146         ktime_t                         rx_tstamp_last_feedback;
 147         struct tfrc_rx_hist             rx_hist;
 148         struct tfrc_loss_hist           rx_li_hist;
 149         u16                             rx_s;
 150 #define rx_pinv                         rx_li_hist.i_mean
 151 };
 152
 153 static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
 154 {
 155         struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
 156         BUG_ON(hcrx == NULL);
 157         return hcrx;
 158 }
 159
 160 #endif /* _DCCP_CCID3_H_ */