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/*
* net/dccp/ccids/lib/loss_interval.c
*
* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/module.h>
#include "loss_interval.h"
struct dccp_li_hist *dccp_li_hist_new(const char *name)
{
struct dccp_li_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
static const char dccp_li_hist_mask[] = "li_hist_%s";
char *slab_name;
if (hist == NULL)
goto out;
slab_name = kmalloc(strlen(name) + sizeof(dccp_li_hist_mask) - 1,
GFP_ATOMIC);
if (slab_name == NULL)
goto out_free_hist;
sprintf(slab_name, dccp_li_hist_mask, name);
hist->dccplih_slab = kmem_cache_create(slab_name,
sizeof(struct dccp_li_hist_entry),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (hist->dccplih_slab == NULL)
goto out_free_slab_name;
out:
return hist;
out_free_slab_name:
kfree(slab_name);
out_free_hist:
kfree(hist);
hist = NULL;
goto out;
}
EXPORT_SYMBOL_GPL(dccp_li_hist_new);
void dccp_li_hist_delete(struct dccp_li_hist *hist)
{
const char* name = kmem_cache_name(hist->dccplih_slab);
kmem_cache_destroy(hist->dccplih_slab);
kfree(name);
kfree(hist);
}
EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list)
{
struct dccp_li_hist_entry *entry, *next;
list_for_each_entry_safe(entry, next, list, dccplih_node) {
list_del_init(&entry->dccplih_node);
kmem_cache_free(hist->dccplih_slab, entry);
}
}
EXPORT_SYMBOL_GPL(dccp_li_hist_purge);
/* Weights used to calculate loss event rate */
/*
* These are integers as per section 8 of RFC3448. We can then divide by 4 *
* when we use it.
*/
static const int dccp_li_hist_w[DCCP_LI_HIST_IVAL_F_LENGTH] = {
4, 4, 4, 4, 3, 2, 1, 1,
};
u32 dccp_li_hist_calc_i_mean(struct list_head *list)
{
struct dccp_li_hist_entry *li_entry, *li_next;
int i = 0;
u32 i_tot;
u32 i_tot0 = 0;
u32 i_tot1 = 0;
u32 w_tot = 0;
list_for_each_entry_safe(li_entry, li_next, list, dccplih_node) {
if (i < DCCP_LI_HIST_IVAL_F_LENGTH) {
i_tot0 += li_entry->dccplih_interval * dccp_li_hist_w[i];
w_tot += dccp_li_hist_w[i];
}
if (i != 0)
i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1];
if (++i > DCCP_LI_HIST_IVAL_F_LENGTH)
break;
}
if (i != DCCP_LI_HIST_IVAL_F_LENGTH)
return 0;
i_tot = max(i_tot0, i_tot1);
/* FIXME: Why do we do this? -Ian McDonald */
if (i_tot * 4 < w_tot)
i_tot = w_tot * 4;
return i_tot * 4 / w_tot;
}
EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
struct dccp_li_hist_entry *dccp_li_hist_interval_new(struct dccp_li_hist *hist,
struct list_head *list,
const u64 seq_loss,
const u8 win_loss)
{
struct dccp_li_hist_entry *tail = NULL, *entry;
int i;
for (i = 0; i <= DCCP_LI_HIST_IVAL_F_LENGTH; ++i) {
entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
if (entry == NULL) {
dccp_li_hist_purge(hist, list);
return NULL;
}
if (tail == NULL)
tail = entry;
list_add(&entry->dccplih_node, list);
}
entry->dccplih_seqno = seq_loss;
entry->dccplih_win_count = win_loss;
return tail;
}
EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);
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