net/dccp/ccids/lib/loss_interval.h

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