summaryrefslogtreecommitdiffstats
path: root/net/dccp/ccids/lib/packet_history.c
blob: d3f9d205383005eaa08b58ad32ca25e0b69b6537 (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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
/*
 *  net/dccp/packet_history.h
 *
 *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
 *
 *  An implementation of the DCCP protocol
 *
 *  This code has been developed by the University of Waikato WAND
 *  research group. For further information please see http://www.wand.net.nz/
 *  or e-mail Ian McDonald - iam4@cs.waikato.ac.nz
 *
 *  This code also uses code from Lulea University, rereleased as GPL by its
 *  authors:
 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
 *
 *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
 *  and to make it work as a loadable module in the DCCP stack written by
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/string.h>

#include "packet_history.h"

struct dccp_rx_hist *dccp_rx_hist_new(const char *name)
{
	struct dccp_rx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
	static const char dccp_rx_hist_mask[] = "rx_hist_%s";
	char *slab_name;

	if (hist == NULL)
		goto out;

	slab_name = kmalloc(strlen(name) + sizeof(dccp_rx_hist_mask) - 1,
			    GFP_ATOMIC);
	if (slab_name == NULL)
		goto out_free_hist;

	sprintf(slab_name, dccp_rx_hist_mask, name);
	hist->dccprxh_slab = kmem_cache_create(slab_name,
					     sizeof(struct dccp_rx_hist_entry),
					       0, SLAB_HWCACHE_ALIGN,
					       NULL, NULL);
	if (hist->dccprxh_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_rx_hist_new);

void dccp_rx_hist_delete(struct dccp_rx_hist *hist)
{
	const char* name = kmem_cache_name(hist->dccprxh_slab);

	kmem_cache_destroy(hist->dccprxh_slab);
	kfree(name);
	kfree(hist);
}

EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);

void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
{
	struct dccp_rx_hist_entry *entry, *next;

	list_for_each_entry_safe(entry, next, list, dccphrx_node) {
		list_del_init(&entry->dccphrx_node);
		kmem_cache_free(hist->dccprxh_slab, entry);
	}
}

EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);

struct dccp_rx_hist_entry *
		dccp_rx_hist_find_data_packet(const struct list_head *list)
{
	struct dccp_rx_hist_entry *entry, *packet = NULL;

	list_for_each_entry(entry, list, dccphrx_node)
		if (entry->dccphrx_type == DCCP_PKT_DATA ||
		    entry->dccphrx_type == DCCP_PKT_DATAACK) {
			packet = entry;
			break;
		}

	return packet;
}

EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);

int dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
			    struct list_head *rx_list,
			    struct list_head *li_list,
			    struct dccp_rx_hist_entry *packet)
{
	struct dccp_rx_hist_entry *entry, *next, *iter;
	u8 num_later = 0;

	iter = dccp_rx_hist_head(rx_list);
	if (iter == NULL)
		dccp_rx_hist_add_entry(rx_list, packet);
	else {
		const u64 seqno = packet->dccphrx_seqno;

		if (after48(seqno, iter->dccphrx_seqno))
			dccp_rx_hist_add_entry(rx_list, packet);
		else {
			if (dccp_rx_hist_entry_data_packet(iter))
				num_later = 1;

			list_for_each_entry_continue(iter, rx_list,
						     dccphrx_node) {
				if (after48(seqno, iter->dccphrx_seqno)) {
					dccp_rx_hist_add_entry(&iter->dccphrx_node,
							       packet);
					goto trim_history;
				}

				if (dccp_rx_hist_entry_data_packet(iter))
					num_later++;

				if (num_later == TFRC_RECV_NUM_LATE_LOSS) {
					dccp_rx_hist_entry_delete(hist, packet);
					return 1;
				}
			}

			if (num_later < TFRC_RECV_NUM_LATE_LOSS)
				dccp_rx_hist_add_entry(rx_list, packet);
			/*
			 * FIXME: else what? should we destroy the packet
			 * like above?
			 */
		}
	}

trim_history:
	/*
	 * Trim history (remove all packets after the NUM_LATE_LOSS + 1
	 * data packets)
	 */
	num_later = TFRC_RECV_NUM_LATE_LOSS + 1;

	if (!list_empty(li_list)) {
		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
			if (num_later == 0) {
				list_del_init(&entry->dccphrx_node);
				dccp_rx_hist_entry_delete(hist, entry);
			} else if (dccp_rx_hist_entry_data_packet(entry))
				--num_later;
		}
	} else {
		int step = 0;
		u8 win_count = 0; /* Not needed, but lets shut up gcc */
		int tmp;
		/*
		 * We have no loss interval history so we need at least one
		 * rtt:s of data packets to approximate rtt.
		 */
		list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
			if (num_later == 0) {
				switch (step) {
				case 0:
					step = 1;
					/* OK, find next data packet */
					num_later = 1;
					break;
				case 1:
					step = 2;
					/* OK, find next data packet */
					num_later = 1;
					win_count = entry->dccphrx_ccval;
					break;
				case 2:
					tmp = win_count - entry->dccphrx_ccval;
					if (tmp < 0)
						tmp += TFRC_WIN_COUNT_LIMIT;
					if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
						/*
						 * We have found a packet older
						 * than one rtt remove the rest
						 */
						step = 3;
					} else /* OK, find next data packet */
						num_later = 1;
					break;
				case 3:
					list_del_init(&entry->dccphrx_node);
					dccp_rx_hist_entry_delete(hist, entry);
					break;
				}
			} else if (dccp_rx_hist_entry_data_packet(entry))
				--num_later;
		}
	}

	return 0;
}

EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);

u64 dccp_rx_hist_detect_loss(struct list_head *rx_list,
			     struct list_head *li_list, u8 *win_loss)
{
	struct dccp_rx_hist_entry *entry, *next, *packet;
	struct dccp_rx_hist_entry *a_loss = NULL;
	struct dccp_rx_hist_entry *b_loss = NULL;
	u64 seq_loss = DCCP_MAX_SEQNO + 1;
	u8 num_later = TFRC_RECV_NUM_LATE_LOSS;

	list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
		if (num_later == 0) {
			b_loss = entry;
			break;
		} else if (dccp_rx_hist_entry_data_packet(entry))
			--num_later;
	}

	if (b_loss == NULL)
		goto out;

	num_later = 1;
	list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
		if (num_later == 0) {
			a_loss = entry;
			break;
		} else if (dccp_rx_hist_entry_data_packet(entry))
			--num_later;
	}

	if (a_loss == NULL) {
		if (list_empty(li_list)) {
			/* no loss event have occured yet */
			LIMIT_NETDEBUG("%s: TODO: find a lost data packet by "
				       "comparing to initial seqno\n",
				       __FUNCTION__);
			goto out;
		} else {
			LIMIT_NETDEBUG("%s: Less than 4 data pkts in history!",
				       __FUNCTION__);
			goto out;
		}
	}

	/* Locate a lost data packet */
	entry = packet = b_loss;
	list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
		u64 delta = dccp_delta_seqno(entry->dccphrx_seqno,
					     packet->dccphrx_seqno);

		if (delta != 0) {
			if (dccp_rx_hist_entry_data_packet(packet))
				--delta;
			/*
			 * FIXME: check this, probably this % usage is because
			 * in earlier drafts the ndp count was just 8 bits
			 * long, but now it cam be up to 24 bits long.
			 */
#if 0
			if (delta % DCCP_NDP_LIMIT !=
			    (packet->dccphrx_ndp -
			     entry->dccphrx_ndp) % DCCP_NDP_LIMIT)
#endif
			if (delta != packet->dccphrx_ndp - entry->dccphrx_ndp) {
				seq_loss = entry->dccphrx_seqno;
				dccp_inc_seqno(&seq_loss);
			}
		}
		packet = entry;
		if (packet == a_loss)
			break;
	}
out:
	if (seq_loss != DCCP_MAX_SEQNO + 1)
		*win_loss = a_loss->dccphrx_ccval;
	else
		*win_loss = 0; /* Paranoia */

	return seq_loss;
}

EXPORT_SYMBOL_GPL(dccp_rx_hist_detect_loss);

struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
{
	struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
	static const char dccp_tx_hist_mask[] = "tx_hist_%s";
	char *slab_name;

	if (hist == NULL)
		goto out;

	slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
			    GFP_ATOMIC);
	if (slab_name == NULL)
		goto out_free_hist;

	sprintf(slab_name, dccp_tx_hist_mask, name);
	hist->dccptxh_slab = kmem_cache_create(slab_name,
					     sizeof(struct dccp_tx_hist_entry),
					       0, SLAB_HWCACHE_ALIGN,
					       NULL, NULL);
	if (hist->dccptxh_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_tx_hist_new);

void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
{
	const char* name = kmem_cache_name(hist->dccptxh_slab);

	kmem_cache_destroy(hist->dccptxh_slab);
	kfree(name);
	kfree(hist);
}

EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);

struct dccp_tx_hist_entry *
	dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
{
	struct dccp_tx_hist_entry *packet = NULL, *entry;

	list_for_each_entry(entry, list, dccphtx_node)
		if (entry->dccphtx_seqno == seq) {
			packet = entry;
			break;
		}

	return packet;
}

EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);

void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
			      struct list_head *list,
			      struct dccp_tx_hist_entry *packet)
{
	struct dccp_tx_hist_entry *next;

	list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
		list_del_init(&packet->dccphtx_node);
		dccp_tx_hist_entry_delete(hist, packet);
	}
}

EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);

void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
{
	struct dccp_tx_hist_entry *entry, *next;

	list_for_each_entry_safe(entry, next, list, dccphtx_node) {
		list_del_init(&entry->dccphtx_node);
		dccp_tx_hist_entry_delete(hist, entry);
	}
}

EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);

MODULE_AUTHOR("Ian McDonald <iam4@cs.waikato.ac.nz>, "
	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
MODULE_DESCRIPTION("DCCP TFRC library");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud