net/dccp/ccids/lib/loss_interval.h

   1 #ifndef _DCCP_LI_HIST_
   2 #define _DCCP_LI_HIST_
   3 /*
   4  *  net/dccp/ccids/lib/loss_interval.h
   5  *
   6  *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   7  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
   8  *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
   9  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  10  *
  11  *  This program is free software; you can redistribute it and/or modify it
  12  *  under the terms of the GNU General Public License as published by the Free
  13  *  Software Foundation; either version 2 of the License, or (at your option)
  14  *  any later version.
  15  */
  16 #include <linux/ktime.h>
  17 #include <linux/list.h>
  18 #include <linux/slab.h>
  19
  20 /*
  21  * Number of loss intervals (RFC 4342, 8.6.1). The history size is one more than
  22  * NINTERVAL, since the `open' interval I_0 is always stored as the first entry.
  23  */
  24 #define NINTERVAL       8
  25 #define LIH_SIZE        (NINTERVAL + 1)
  26
  27 /**
  28  *  tfrc_loss_interval  -  Loss history record for TFRC-based protocols
  29  *  @li_seqno:          Highest received seqno before the start of loss
  30  *  @li_ccval:          The CCVal belonging to @li_seqno
  31  *  @li_is_closed:      Whether @li_seqno is older than 1 RTT
  32  *  @li_length:         Loss interval sequence length
  33  */
  34 struct tfrc_loss_interval {
  35         u64              li_seqno:48,
  36                          li_ccval:4,
  37                          li_is_closed:1;
  38         u32              li_length;
  39 };
  40
  41 /**
  42  *  tfrc_loss_hist  -  Loss record database
  43  *  @ring:      Circular queue managed in LIFO manner
  44  *  @counter:   Current count of entries (can be more than %LIH_SIZE)
  45  *  @i_mean:    Current Average Loss Interval [RFC 3448, 5.4]
  46  */
  47 struct tfrc_loss_hist {
  48         struct tfrc_loss_interval       *ring[LIH_SIZE];
  49         u8                              counter;
  50         u32                             i_mean;
  51 };
  52
  53 static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
  54 {
  55         memset(lh, 0, sizeof(struct tfrc_loss_hist));
  56 }
  57
  58 static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
  59 {
  60         return lh->counter > 0;
  61 }
  62
  63 static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
  64 {
  65         return min(lh->counter, (u8)LIH_SIZE);
  66 }
  67
  68 struct tfrc_rx_hist;
  69
  70 extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
  71                                  u32 (*first_li)(struct sock *), struct sock *);
  72 extern u8   tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
  73 extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
  74
  75 #endif /* _DCCP_LI_HIST_ */