1/*
2 *  net/dccp/packet_history.c
3 *
4 *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
5 *
6 *  An implementation of the DCCP protocol
7 *
8 *  This code has been developed by the University of Waikato WAND
9 *  research group. For further information please see http://www.wand.net.nz/
10 *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
11 *
12 *  This code also uses code from Lulea University, rereleased as GPL by its
13 *  authors:
14 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
15 *
16 *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17 *  and to make it work as a loadable module in the DCCP stack written by
18 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
19 *
20 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
21 *
22 *  This program is free software; you can redistribute it and/or modify
23 *  it under the terms of the GNU General Public License as published by
24 *  the Free Software Foundation; either version 2 of the License, or
25 *  (at your option) any later version.
26 *
27 *  This program is distributed in the hope that it will be useful,
28 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
29 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
30 *  GNU General Public License for more details.
31 *
32 *  You should have received a copy of the GNU General Public License
33 *  along with this program; if not, write to the Free Software
34 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
35 */
36
37#include <linux/module.h>
38#include <linux/string.h>
39#include "packet_history.h"
40
41/*
42 * 	Transmitter History Routines
43 */
44struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
45{
46	struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
47	static const char dccp_tx_hist_mask[] = "tx_hist_%s";
48	char *slab_name;
49
50	if (hist == NULL)
51		goto out;
52
53	slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
54			    GFP_ATOMIC);
55	if (slab_name == NULL)
56		goto out_free_hist;
57
58	sprintf(slab_name, dccp_tx_hist_mask, name);
59	hist->dccptxh_slab = kmem_cache_create(slab_name,
60					     sizeof(struct dccp_tx_hist_entry),
61					       0, SLAB_HWCACHE_ALIGN,
62					       NULL, NULL);
63	if (hist->dccptxh_slab == NULL)
64		goto out_free_slab_name;
65out:
66	return hist;
67out_free_slab_name:
68	kfree(slab_name);
69out_free_hist:
70	kfree(hist);
71	hist = NULL;
72	goto out;
73}
74
75EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
76
77void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
78{
79	const char* name = kmem_cache_name(hist->dccptxh_slab);
80
81	kmem_cache_destroy(hist->dccptxh_slab);
82	kfree(name);
83	kfree(hist);
84}
85
86EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
87
88struct dccp_tx_hist_entry *
89	dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
90{
91	struct dccp_tx_hist_entry *packet = NULL, *entry;
92
93	list_for_each_entry(entry, list, dccphtx_node)
94		if (entry->dccphtx_seqno == seq) {
95			packet = entry;
96			break;
97		}
98
99	return packet;
100}
101
102EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
103
104void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
105{
106	struct dccp_tx_hist_entry *entry, *next;
107
108	list_for_each_entry_safe(entry, next, list, dccphtx_node) {
109		list_del_init(&entry->dccphtx_node);
110		dccp_tx_hist_entry_delete(hist, entry);
111	}
112}
113
114EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
115
116void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
117			      struct list_head *list,
118			      struct dccp_tx_hist_entry *packet)
119{
120	struct dccp_tx_hist_entry *next;
121
122	list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
123		list_del_init(&packet->dccphtx_node);
124		dccp_tx_hist_entry_delete(hist, packet);
125	}
126}
127
128EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
129
130/*
131 * 	Receiver History Routines
132 */
133struct dccp_rx_hist *dccp_rx_hist_new(const char *name)
134{
135	struct dccp_rx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
136	static const char dccp_rx_hist_mask[] = "rx_hist_%s";
137	char *slab_name;
138
139	if (hist == NULL)
140		goto out;
141
142	slab_name = kmalloc(strlen(name) + sizeof(dccp_rx_hist_mask) - 1,
143			    GFP_ATOMIC);
144	if (slab_name == NULL)
145		goto out_free_hist;
146
147	sprintf(slab_name, dccp_rx_hist_mask, name);
148	hist->dccprxh_slab = kmem_cache_create(slab_name,
149					     sizeof(struct dccp_rx_hist_entry),
150					       0, SLAB_HWCACHE_ALIGN,
151					       NULL, NULL);
152	if (hist->dccprxh_slab == NULL)
153		goto out_free_slab_name;
154out:
155	return hist;
156out_free_slab_name:
157	kfree(slab_name);
158out_free_hist:
159	kfree(hist);
160	hist = NULL;
161	goto out;
162}
163
164EXPORT_SYMBOL_GPL(dccp_rx_hist_new);
165
166void dccp_rx_hist_delete(struct dccp_rx_hist *hist)
167{
168	const char* name = kmem_cache_name(hist->dccprxh_slab);
169
170	kmem_cache_destroy(hist->dccprxh_slab);
171	kfree(name);
172	kfree(hist);
173}
174
175EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);
176
177int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
178			    u8 *ccval)
179{
180	struct dccp_rx_hist_entry *packet = NULL, *entry;
181
182	list_for_each_entry(entry, list, dccphrx_node)
183		if (entry->dccphrx_seqno == seq) {
184			packet = entry;
185			break;
186		}
187
188	if (packet)
189		*ccval = packet->dccphrx_ccval;
190
191	return packet != NULL;
192}
193
194EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
195struct dccp_rx_hist_entry *
196		dccp_rx_hist_find_data_packet(const struct list_head *list)
197{
198	struct dccp_rx_hist_entry *entry, *packet = NULL;
199
200	list_for_each_entry(entry, list, dccphrx_node)
201		if (entry->dccphrx_type == DCCP_PKT_DATA ||
202		    entry->dccphrx_type == DCCP_PKT_DATAACK) {
203			packet = entry;
204			break;
205		}
206
207	return packet;
208}
209
210EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
211
212void dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
213			    struct list_head *rx_list,
214			    struct list_head *li_list,
215			    struct dccp_rx_hist_entry *packet,
216			    u64 nonloss_seqno)
217{
218	struct dccp_rx_hist_entry *entry, *next;
219	u8 num_later = 0;
220
221	list_add(&packet->dccphrx_node, rx_list);
222
223	num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
224
225	if (!list_empty(li_list)) {
226		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
227			if (num_later == 0) {
228				if (after48(nonloss_seqno,
229				   entry->dccphrx_seqno)) {
230					list_del_init(&entry->dccphrx_node);
231					dccp_rx_hist_entry_delete(hist, entry);
232				}
233			} else if (dccp_rx_hist_entry_data_packet(entry))
234				--num_later;
235		}
236	} else {
237		int step = 0;
238		u8 win_count = 0; /* Not needed, but lets shut up gcc */
239		int tmp;
240		/*
241		 * We have no loss interval history so we need at least one
242		 * rtt:s of data packets to approximate rtt.
243		 */
244		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
245			if (num_later == 0) {
246				switch (step) {
247				case 0:
248					step = 1;
249					/* OK, find next data packet */
250					num_later = 1;
251					break;
252				case 1:
253					step = 2;
254					/* OK, find next data packet */
255					num_later = 1;
256					win_count = entry->dccphrx_ccval;
257					break;
258				case 2:
259					tmp = win_count - entry->dccphrx_ccval;
260					if (tmp < 0)
261						tmp += TFRC_WIN_COUNT_LIMIT;
262					if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
263						/*
264						 * We have found a packet older
265						 * than one rtt remove the rest
266						 */
267						step = 3;
268					} else /* OK, find next data packet */
269						num_later = 1;
270					break;
271				case 3:
272					list_del_init(&entry->dccphrx_node);
273					dccp_rx_hist_entry_delete(hist, entry);
274					break;
275				}
276			} else if (dccp_rx_hist_entry_data_packet(entry))
277				--num_later;
278		}
279	}
280}
281
282EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
283
284void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
285{
286	struct dccp_rx_hist_entry *entry, *next;
287
288	list_for_each_entry_safe(entry, next, list, dccphrx_node) {
289		list_del_init(&entry->dccphrx_node);
290		kmem_cache_free(hist->dccprxh_slab, entry);
291	}
292}
293
294EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
295
296
297MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
298	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
299MODULE_DESCRIPTION("DCCP TFRC library");
300MODULE_LICENSE("GPL");
301