net/dccp/ccids/lib/loss_interval.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 #ifndef _DCCP_LI_HIST_
   3 #define _DCCP_LI_HIST_
   4 /*
   5  *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   6  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
   7  *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
   8  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   9  */
  10 #include <linux/ktime.h>
  11 #include <linux/list.h>
  12 #include <linux/slab.h>
  13
  14 /*
  15  * Number of loss intervals (RFC 4342, 8.6.1). The history size is one more than
  16  * NINTERVAL, since the `open' interval I_0 is always stored as the first entry.
  17  */
  18 #define NINTERVAL       8
  19 #define LIH_SIZE        (NINTERVAL + 1)
  20
  21 /**
  22  *  tfrc_loss_interval  -  Loss history record for TFRC-based protocols
  23  *  @li_seqno:          Highest received seqno before the start of loss
  24  *  @li_ccval:          The CCVal belonging to @li_seqno
  25  *  @li_is_closed:      Whether @li_seqno is older than 1 RTT
  26  *  @li_length:         Loss interval sequence length
  27  */
  28 struct tfrc_loss_interval {
  29         u64              li_seqno:48,
  30                          li_ccval:4,
  31                          li_is_closed:1;
  32         u32              li_length;
  33 };
  34
  35 /**
  36  *  tfrc_loss_hist  -  Loss record database
  37  *  @ring:      Circular queue managed in LIFO manner
  38  *  @counter:   Current count of entries (can be more than %LIH_SIZE)
  39  *  @i_mean:    Current Average Loss Interval [RFC 3448, 5.4]
  40  */
  41 struct tfrc_loss_hist {
  42         struct tfrc_loss_interval       *ring[LIH_SIZE];
  43         u8                              counter;
  44         u32                             i_mean;
  45 };
  46
  47 static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
  48 {
  49         memset(lh, 0, sizeof(struct tfrc_loss_hist));
  50 }
  51
  52 static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
  53 {
  54         return lh->counter > 0;
  55 }
  56
  57 static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
  58 {
  59         return min(lh->counter, (u8)LIH_SIZE);
  60 }
  61
  62 struct tfrc_rx_hist;
  63
  64 int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
  65                          u32 (*first_li)(struct sock *), struct sock *);
  66 u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
  67 void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
  68
  69 #endif /* _DCCP_LI_HIST_ */