xref: /openbmc/linux/net/dccp/ccids/lib/loss_interval.c (revision e6bccd357343e98db9e1fd0d487f4f924e1a7921)
1ae6706f0SArnaldo Carvalho de Melo /*
2ae6706f0SArnaldo Carvalho de Melo  *  net/dccp/ccids/lib/loss_interval.c
3ae6706f0SArnaldo Carvalho de Melo  *
4ae6706f0SArnaldo Carvalho de Melo  *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
5*e6bccd35SIan McDonald  *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
6ae6706f0SArnaldo Carvalho de Melo  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7ae6706f0SArnaldo Carvalho de Melo  *
8ae6706f0SArnaldo Carvalho de Melo  *  This program is free software; you can redistribute it and/or modify
9ae6706f0SArnaldo Carvalho de Melo  *  it under the terms of the GNU General Public License as published by
10ae6706f0SArnaldo Carvalho de Melo  *  the Free Software Foundation; either version 2 of the License, or
11ae6706f0SArnaldo Carvalho de Melo  *  (at your option) any later version.
12ae6706f0SArnaldo Carvalho de Melo  */
13ae6706f0SArnaldo Carvalho de Melo 
14ae6706f0SArnaldo Carvalho de Melo #include <linux/module.h>
15ae6706f0SArnaldo Carvalho de Melo 
16ae6706f0SArnaldo Carvalho de Melo #include "loss_interval.h"
17ae6706f0SArnaldo Carvalho de Melo 
18ae6706f0SArnaldo Carvalho de Melo struct dccp_li_hist *dccp_li_hist_new(const char *name)
19ae6706f0SArnaldo Carvalho de Melo {
20ae6706f0SArnaldo Carvalho de Melo 	struct dccp_li_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
21ae6706f0SArnaldo Carvalho de Melo 	static const char dccp_li_hist_mask[] = "li_hist_%s";
22ae6706f0SArnaldo Carvalho de Melo 	char *slab_name;
23ae6706f0SArnaldo Carvalho de Melo 
24ae6706f0SArnaldo Carvalho de Melo 	if (hist == NULL)
25ae6706f0SArnaldo Carvalho de Melo 		goto out;
26ae6706f0SArnaldo Carvalho de Melo 
27ae6706f0SArnaldo Carvalho de Melo 	slab_name = kmalloc(strlen(name) + sizeof(dccp_li_hist_mask) - 1,
28ae6706f0SArnaldo Carvalho de Melo 			    GFP_ATOMIC);
29ae6706f0SArnaldo Carvalho de Melo 	if (slab_name == NULL)
30ae6706f0SArnaldo Carvalho de Melo 		goto out_free_hist;
31ae6706f0SArnaldo Carvalho de Melo 
32ae6706f0SArnaldo Carvalho de Melo 	sprintf(slab_name, dccp_li_hist_mask, name);
33ae6706f0SArnaldo Carvalho de Melo 	hist->dccplih_slab = kmem_cache_create(slab_name,
34ae6706f0SArnaldo Carvalho de Melo 					     sizeof(struct dccp_li_hist_entry),
35ae6706f0SArnaldo Carvalho de Melo 					       0, SLAB_HWCACHE_ALIGN,
36ae6706f0SArnaldo Carvalho de Melo 					       NULL, NULL);
37ae6706f0SArnaldo Carvalho de Melo 	if (hist->dccplih_slab == NULL)
38ae6706f0SArnaldo Carvalho de Melo 		goto out_free_slab_name;
39ae6706f0SArnaldo Carvalho de Melo out:
40ae6706f0SArnaldo Carvalho de Melo 	return hist;
41ae6706f0SArnaldo Carvalho de Melo out_free_slab_name:
42ae6706f0SArnaldo Carvalho de Melo 	kfree(slab_name);
43ae6706f0SArnaldo Carvalho de Melo out_free_hist:
44ae6706f0SArnaldo Carvalho de Melo 	kfree(hist);
45ae6706f0SArnaldo Carvalho de Melo 	hist = NULL;
46ae6706f0SArnaldo Carvalho de Melo 	goto out;
47ae6706f0SArnaldo Carvalho de Melo }
48ae6706f0SArnaldo Carvalho de Melo 
49ae6706f0SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(dccp_li_hist_new);
50ae6706f0SArnaldo Carvalho de Melo 
51ae6706f0SArnaldo Carvalho de Melo void dccp_li_hist_delete(struct dccp_li_hist *hist)
52ae6706f0SArnaldo Carvalho de Melo {
53ae6706f0SArnaldo Carvalho de Melo 	const char* name = kmem_cache_name(hist->dccplih_slab);
54ae6706f0SArnaldo Carvalho de Melo 
55ae6706f0SArnaldo Carvalho de Melo 	kmem_cache_destroy(hist->dccplih_slab);
56ae6706f0SArnaldo Carvalho de Melo 	kfree(name);
57ae6706f0SArnaldo Carvalho de Melo 	kfree(hist);
58ae6706f0SArnaldo Carvalho de Melo }
59ae6706f0SArnaldo Carvalho de Melo 
60ae6706f0SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
61ae6706f0SArnaldo Carvalho de Melo 
62ae6706f0SArnaldo Carvalho de Melo void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list)
63ae6706f0SArnaldo Carvalho de Melo {
64ae6706f0SArnaldo Carvalho de Melo 	struct dccp_li_hist_entry *entry, *next;
65ae6706f0SArnaldo Carvalho de Melo 
66ae6706f0SArnaldo Carvalho de Melo 	list_for_each_entry_safe(entry, next, list, dccplih_node) {
67ae6706f0SArnaldo Carvalho de Melo 		list_del_init(&entry->dccplih_node);
68ae6706f0SArnaldo Carvalho de Melo 		kmem_cache_free(hist->dccplih_slab, entry);
69ae6706f0SArnaldo Carvalho de Melo 	}
70ae6706f0SArnaldo Carvalho de Melo }
71ae6706f0SArnaldo Carvalho de Melo 
72ae6706f0SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(dccp_li_hist_purge);
73ae6706f0SArnaldo Carvalho de Melo 
74ae6706f0SArnaldo Carvalho de Melo /* Weights used to calculate loss event rate */
75ae6706f0SArnaldo Carvalho de Melo /*
76ae6706f0SArnaldo Carvalho de Melo  * These are integers as per section 8 of RFC3448. We can then divide by 4 *
77ae6706f0SArnaldo Carvalho de Melo  * when we use it.
78ae6706f0SArnaldo Carvalho de Melo  */
79ae6706f0SArnaldo Carvalho de Melo static const int dccp_li_hist_w[DCCP_LI_HIST_IVAL_F_LENGTH] = {
80ae6706f0SArnaldo Carvalho de Melo 	4, 4, 4, 4, 3, 2, 1, 1,
81ae6706f0SArnaldo Carvalho de Melo };
82ae6706f0SArnaldo Carvalho de Melo 
83ae6706f0SArnaldo Carvalho de Melo u32 dccp_li_hist_calc_i_mean(struct list_head *list)
84ae6706f0SArnaldo Carvalho de Melo {
85ae6706f0SArnaldo Carvalho de Melo 	struct dccp_li_hist_entry *li_entry, *li_next;
86ae6706f0SArnaldo Carvalho de Melo 	int i = 0;
87ae6706f0SArnaldo Carvalho de Melo 	u32 i_tot;
88ae6706f0SArnaldo Carvalho de Melo 	u32 i_tot0 = 0;
89ae6706f0SArnaldo Carvalho de Melo 	u32 i_tot1 = 0;
90ae6706f0SArnaldo Carvalho de Melo 	u32 w_tot  = 0;
91ae6706f0SArnaldo Carvalho de Melo 
92ae6706f0SArnaldo Carvalho de Melo 	list_for_each_entry_safe(li_entry, li_next, list, dccplih_node) {
93ae6706f0SArnaldo Carvalho de Melo 		if (i < DCCP_LI_HIST_IVAL_F_LENGTH) {
94ae6706f0SArnaldo Carvalho de Melo 			i_tot0 += li_entry->dccplih_interval * dccp_li_hist_w[i];
95ae6706f0SArnaldo Carvalho de Melo 			w_tot  += dccp_li_hist_w[i];
96ae6706f0SArnaldo Carvalho de Melo 		}
97ae6706f0SArnaldo Carvalho de Melo 
98ae6706f0SArnaldo Carvalho de Melo 		if (i != 0)
99ae6706f0SArnaldo Carvalho de Melo 			i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1];
100ae6706f0SArnaldo Carvalho de Melo 
101ae6706f0SArnaldo Carvalho de Melo 		if (++i > DCCP_LI_HIST_IVAL_F_LENGTH)
102ae6706f0SArnaldo Carvalho de Melo 			break;
103ae6706f0SArnaldo Carvalho de Melo 	}
104ae6706f0SArnaldo Carvalho de Melo 
105ae6706f0SArnaldo Carvalho de Melo 	if (i != DCCP_LI_HIST_IVAL_F_LENGTH)
106ae6706f0SArnaldo Carvalho de Melo 		return 0;
107ae6706f0SArnaldo Carvalho de Melo 
108ae6706f0SArnaldo Carvalho de Melo 	i_tot = max(i_tot0, i_tot1);
109ae6706f0SArnaldo Carvalho de Melo 
110ae6706f0SArnaldo Carvalho de Melo 	/* FIXME: Why do we do this? -Ian McDonald */
111ae6706f0SArnaldo Carvalho de Melo 	if (i_tot * 4 < w_tot)
112ae6706f0SArnaldo Carvalho de Melo 		i_tot = w_tot * 4;
113ae6706f0SArnaldo Carvalho de Melo 
114ae6706f0SArnaldo Carvalho de Melo 	return i_tot * 4 / w_tot;
115ae6706f0SArnaldo Carvalho de Melo }
116ae6706f0SArnaldo Carvalho de Melo 
117ae6706f0SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
118ae6706f0SArnaldo Carvalho de Melo 
119ae6706f0SArnaldo Carvalho de Melo struct dccp_li_hist_entry *dccp_li_hist_interval_new(struct dccp_li_hist *hist,
120ae6706f0SArnaldo Carvalho de Melo 						     struct list_head *list,
121ae6706f0SArnaldo Carvalho de Melo 						     const u64 seq_loss,
122ae6706f0SArnaldo Carvalho de Melo 						     const u8 win_loss)
123ae6706f0SArnaldo Carvalho de Melo {
124ae6706f0SArnaldo Carvalho de Melo 	struct dccp_li_hist_entry *tail = NULL, *entry;
125ae6706f0SArnaldo Carvalho de Melo 	int i;
126ae6706f0SArnaldo Carvalho de Melo 
127ae6706f0SArnaldo Carvalho de Melo 	for (i = 0; i <= DCCP_LI_HIST_IVAL_F_LENGTH; ++i) {
128ae6706f0SArnaldo Carvalho de Melo 		entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
129ae6706f0SArnaldo Carvalho de Melo 		if (entry == NULL) {
130ae6706f0SArnaldo Carvalho de Melo 			dccp_li_hist_purge(hist, list);
131ae6706f0SArnaldo Carvalho de Melo 			return NULL;
132ae6706f0SArnaldo Carvalho de Melo 		}
133ae6706f0SArnaldo Carvalho de Melo 		if (tail == NULL)
134ae6706f0SArnaldo Carvalho de Melo 			tail = entry;
135ae6706f0SArnaldo Carvalho de Melo 		list_add(&entry->dccplih_node, list);
136ae6706f0SArnaldo Carvalho de Melo 	}
137ae6706f0SArnaldo Carvalho de Melo 
138ae6706f0SArnaldo Carvalho de Melo 	entry->dccplih_seqno     = seq_loss;
139ae6706f0SArnaldo Carvalho de Melo 	entry->dccplih_win_count = win_loss;
140ae6706f0SArnaldo Carvalho de Melo 	return tail;
141ae6706f0SArnaldo Carvalho de Melo }
142ae6706f0SArnaldo Carvalho de Melo 
143ae6706f0SArnaldo Carvalho de Melo EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);
144