net/dccp/ccids/ccid3.h

   1 /*
   2  *  net/dccp/ccids/ccid3.h
   3  *
   4  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
   5  *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   6  *
   7  *  An implementation of the DCCP protocol
   8  *
   9  *  This code has been developed by the University of Waikato WAND
  10  *  research group. For further information please see http://www.wand.net.nz/
  11  *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
  12  *
  13  *  This code also uses code from Lulea University, rereleased as GPL by its
  14  *  authors:
  15  *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
  16  *
  17  *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
  18  *  and to make it work as a loadable module in the DCCP stack written by
  19  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
  20  *
  21  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  22  *
  23  *  This program is free software; you can redistribute it and/or modify
  24  *  it under the terms of the GNU General Public License as published by
  25  *  the Free Software Foundation; either version 2 of the License, or
  26  *  (at your option) any later version.
  27  *
  28  *  This program is distributed in the hope that it will be useful,
  29  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  30  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  31  *  GNU General Public License for more details.
  32  *
  33  *  You should have received a copy of the GNU General Public License
  34  *  along with this program; if not, write to the Free Software
  35  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  36  */
  37 #ifndef _DCCP_CCID3_H_
  38 #define _DCCP_CCID3_H_
  39
  40 #include <linux/ktime.h>
  41 #include <linux/list.h>
  42 #include <linux/types.h>
  43 #include <linux/tfrc.h>
  44 #include "lib/tfrc.h"
  45 #include "../ccid.h"
  46
  47 /* Two seconds as per RFC 3448 4.2 */
  48 #define TFRC_INITIAL_TIMEOUT       (2 * USEC_PER_SEC)
  49
  50 /* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
  51 #define TFRC_T_MBI                 64
  52
  53 /*
  54  * The t_delta parameter (RFC 3448, 4.6): delays of less than %USEC_PER_MSEC are
  55  * rounded down to 0, since sk_reset_timer() here uses millisecond granularity.
  56  * Hence we can use a constant t_delta = %USEC_PER_MSEC when HZ >= 500. A coarse
  57  * resolution of HZ < 500 means that the error is below one timer tick (t_gran)
  58  * when using the constant t_delta  =  t_gran / 2  =  %USEC_PER_SEC / (2 * HZ).
  59  */
  60 #if (HZ >= 500)
  61 # define TFRC_T_DELTA              USEC_PER_MSEC
  62 #else
  63 # define TFRC_T_DELTA              (USEC_PER_SEC / (2 * HZ))
  64 #warning Coarse CONFIG_HZ resolution -- higher value recommended for TFRC.
  65 #endif
  66
  67 enum ccid3_options {
  68         TFRC_OPT_LOSS_EVENT_RATE = 192,
  69         TFRC_OPT_LOSS_INTERVALS  = 193,
  70         TFRC_OPT_RECEIVE_RATE    = 194,
  71 };
  72
  73 /** struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
  74  *
  75  * @x - Current sending rate in 64 * bytes per second
  76  * @x_recv - Receive rate    in 64 * bytes per second
  77  * @x_calc - Calculated rate in bytes per second
  78  * @rtt - Estimate of current round trip time in usecs
  79  * @p - Current loss event rate (0-1) scaled by 1000000
  80  * @s - Packet size in bytes
  81  * @t_rto - Nofeedback Timer setting in usecs
  82  * @t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs
  83  * @feedback - Whether feedback has been received or not
  84  * @last_win_count - Last window counter sent
  85  * @t_last_win_count - Timestamp of earliest packet with
  86  *                     last_win_count value sent
  87  * @no_feedback_timer - Handle to no feedback timer
  88  * @t_ld - Time last doubled during slow start
  89  * @t_nom - Nominal send time of next packet
  90  * @hist - Packet history
  91  */
  92 struct ccid3_hc_tx_sock {
  93         u64                             x;
  94         u64                             x_recv;
  95         u32                             x_calc;
  96         u32                             rtt;
  97         u32                             p;
  98         u32                             t_rto;
  99         u32                             t_ipi;
 100         u16                             s;
 101         bool                            feedback:1;
 102         u8                              last_win_count;
 103         ktime_t                         t_last_win_count;
 104         struct timer_list               no_feedback_timer;
 105         ktime_t                         t_ld;
 106         ktime_t                         t_nom;
 107         struct tfrc_tx_hist_entry       *hist;
 108 };
 109
 110 static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
 111 {
 112     struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
 113     BUG_ON(hctx == NULL);
 114     return hctx;
 115 }
 116
 117
 118 enum ccid3_fback_type {
 119         CCID3_FBACK_NONE = 0,
 120         CCID3_FBACK_INITIAL,
 121         CCID3_FBACK_PERIODIC,
 122         CCID3_FBACK_PARAM_CHANGE
 123 };
 124
 125 /** struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
 126  *
 127  *  @last_counter  -  Tracks window counter (RFC 4342, 8.1)
 128  *  @feedback  -  The type of the feedback last sent
 129  *  @x_recv  -  Receiver estimate of send rate (RFC 3448, sec. 4.3)
 130  *  @rtt  -  Receiver estimate of RTT
 131  *  @tstamp_last_feedback  -  Time at which last feedback was sent
 132  *  @hist  -  Packet history (loss detection + RTT sampling)
 133  *  @li_hist  -  Loss Interval database
 134  *  @p_inverse  -  Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
 135  */
 136 struct ccid3_hc_rx_sock {
 137         u8                              last_counter:4;
 138         enum ccid3_fback_type           feedback:4;
 139         u32                             x_recv;
 140         u32                             rtt;
 141         ktime_t                         tstamp_last_feedback;
 142         struct tfrc_rx_hist             hist;
 143         struct tfrc_loss_hist           li_hist;
 144 #define p_inverse                       li_hist.i_mean
 145 };
 146
 147 static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
 148 {
 149     struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
 150     BUG_ON(hcrx == NULL);
 151     return hcrx;
 152 }
 153
 154 #endif /* _DCCP_CCID3_H_ */