linux/net/dccp/ccids/lib/loss_interval.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
 *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
 *  Copyright (c) 2005-7 Ian McDonald <[email protected]>
 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[email protected]>
 */
#include <net/sock.h>
#include "tfrc.h"

static struct kmem_cache  *tfrc_lh_slab  __read_mostly;
/* Loss Interval weights from [RFC 3448, 5.4], scaled by 10 */
static const int tfrc_lh_weights[NINTERVAL] = …;

/* implements LIFO semantics on the array */
static inline u8 LIH_INDEX(const u8 ctr)
{ … }

/* the `counter' index always points at the next entry to be populated */
static inline struct tfrc_loss_interval *tfrc_lh_peek(struct tfrc_loss_hist *lh)
{ … }

/* given i with 0 <= i <= k, return I_i as per the rfc3448bis notation */
static inline u32 tfrc_lh_get_interval(struct tfrc_loss_hist *lh, const u8 i)
{ … }

/*
 *	On-demand allocation and de-allocation of entries
 */
static struct tfrc_loss_interval *tfrc_lh_demand_next(struct tfrc_loss_hist *lh)
{ … }

void tfrc_lh_cleanup(struct tfrc_loss_hist *lh)
{ … }

static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
{ … }

/**
 * tfrc_lh_update_i_mean  -  Update the `open' loss interval I_0
 * @lh: histogram to update
 * @skb: received socket triggering loss interval update
 *
 * For recomputing p: returns `true' if p > p_prev  <=>  1/p < 1/p_prev
 */
u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
{ … }

/* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
				     struct tfrc_rx_hist_entry *new_loss)
{ … }

/**
 * tfrc_lh_interval_add  -  Insert new record into the Loss Interval database
 * @lh:		   Loss Interval database
 * @rh:		   Receive history containing a fresh loss event
 * @calc_first_li: Caller-dependent routine to compute length of first interval
 * @sk:		   Used by @calc_first_li in caller-specific way (subtyping)
 *
 * Updates I_mean and returns 1 if a new interval has in fact been added to @lh.
 */
int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
			 u32 (*calc_first_li)(struct sock *), struct sock *sk)
{ … }

int __init tfrc_li_init(void)
{ … }

void tfrc_li_exit(void)
{ … }