summaryrefslogtreecommitdiff
path: root/net/dccp/ccids/lib/loss_interval.c
blob: b93d9fc98cb8cf7139db97e459d6aed60d8eb992 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 *  net/dccp/ccids/lib/loss_interval.c
 *
 *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
 *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.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/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);