Merge HEAD from master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / net / dccp / ccids / lib / packet_history.c
1 /*
2  *  net/dccp/packet_history.h
3  *
4  *  Copyright (c) 2005 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 - iam4@cs.waikato.ac.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/config.h>
38 #include <linux/module.h>
39 #include <linux/string.h>
40
41 #include "packet_history.h"
42
43 struct dccp_rx_hist *dccp_rx_hist_new(const char *name)
44 {
45         struct dccp_rx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
46         static const char dccp_rx_hist_mask[] = "rx_hist_%s";
47         char *slab_name;
48
49         if (hist == NULL)
50                 goto out;
51
52         slab_name = kmalloc(strlen(name) + sizeof(dccp_rx_hist_mask) - 1,
53                             GFP_ATOMIC);
54         if (slab_name == NULL)
55                 goto out_free_hist;
56
57         sprintf(slab_name, dccp_rx_hist_mask, name);
58         hist->dccprxh_slab = kmem_cache_create(slab_name,
59                                              sizeof(struct dccp_rx_hist_entry),
60                                                0, SLAB_HWCACHE_ALIGN,
61                                                NULL, NULL);
62         if (hist->dccprxh_slab == NULL)
63                 goto out_free_slab_name;
64 out:
65         return hist;
66 out_free_slab_name:
67         kfree(slab_name);
68 out_free_hist:
69         kfree(hist);
70         hist = NULL;
71         goto out;
72 }
73
74 EXPORT_SYMBOL_GPL(dccp_rx_hist_new);
75
76 void dccp_rx_hist_delete(struct dccp_rx_hist *hist)
77 {
78         const char* name = kmem_cache_name(hist->dccprxh_slab);
79
80         kmem_cache_destroy(hist->dccprxh_slab);
81         kfree(name);
82         kfree(hist);
83 }
84
85 EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);
86
87 void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
88 {
89         struct dccp_rx_hist_entry *entry, *next;
90
91         list_for_each_entry_safe(entry, next, list, dccphrx_node) {
92                 list_del_init(&entry->dccphrx_node);
93                 kmem_cache_free(hist->dccprxh_slab, entry);
94         }
95 }
96
97 EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
98
99 struct dccp_rx_hist_entry *
100                 dccp_rx_hist_find_data_packet(const struct list_head *list)
101 {
102         struct dccp_rx_hist_entry *entry, *packet = NULL;
103
104         list_for_each_entry(entry, list, dccphrx_node)
105                 if (entry->dccphrx_type == DCCP_PKT_DATA ||
106                     entry->dccphrx_type == DCCP_PKT_DATAACK) {
107                         packet = entry;
108                         break;
109                 }
110
111         return packet;
112 }
113
114 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
115
116 int dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
117                             struct list_head *rx_list,
118                             struct list_head *li_list,
119                             struct dccp_rx_hist_entry *packet)
120 {
121         struct dccp_rx_hist_entry *entry, *next, *iter;
122         u8 num_later = 0;
123
124         iter = dccp_rx_hist_head(rx_list);
125         if (iter == NULL)
126                 dccp_rx_hist_add_entry(rx_list, packet);
127         else {
128                 const u64 seqno = packet->dccphrx_seqno;
129
130                 if (after48(seqno, iter->dccphrx_seqno))
131                         dccp_rx_hist_add_entry(rx_list, packet);
132                 else {
133                         if (dccp_rx_hist_entry_data_packet(iter))
134                                 num_later = 1;
135
136                         list_for_each_entry_continue(iter, rx_list,
137                                                      dccphrx_node) {
138                                 if (after48(seqno, iter->dccphrx_seqno)) {
139                                         dccp_rx_hist_add_entry(&iter->dccphrx_node,
140                                                                packet);
141                                         goto trim_history;
142                                 }
143
144                                 if (dccp_rx_hist_entry_data_packet(iter))
145                                         num_later++;
146
147                                 if (num_later == TFRC_RECV_NUM_LATE_LOSS) {
148                                         dccp_rx_hist_entry_delete(hist, packet);
149                                         return 1;
150                                 }
151                         }
152
153                         if (num_later < TFRC_RECV_NUM_LATE_LOSS)
154                                 dccp_rx_hist_add_entry(rx_list, packet);
155                         /*
156                          * FIXME: else what? should we destroy the packet
157                          * like above?
158                          */
159                 }
160         }
161
162 trim_history:
163         /*
164          * Trim history (remove all packets after the NUM_LATE_LOSS + 1
165          * data packets)
166          */
167         num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
168
169         if (!list_empty(li_list)) {
170                 list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
171                         if (num_later == 0) {
172                                 list_del_init(&entry->dccphrx_node);
173                                 dccp_rx_hist_entry_delete(hist, entry);
174                         } else if (dccp_rx_hist_entry_data_packet(entry))
175                                 --num_later;
176                 }
177         } else {
178                 int step = 0;
179                 u8 win_count = 0; /* Not needed, but lets shut up gcc */
180                 int tmp;
181                 /*
182                  * We have no loss interval history so we need at least one
183                  * rtt:s of data packets to approximate rtt.
184                  */
185                 list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
186                         if (num_later == 0) {
187                                 switch (step) {
188                                 case 0:
189                                         step = 1;
190                                         /* OK, find next data packet */
191                                         num_later = 1;
192                                         break;
193                                 case 1:
194                                         step = 2;
195                                         /* OK, find next data packet */
196                                         num_later = 1;
197                                         win_count = entry->dccphrx_ccval;
198                                         break;
199                                 case 2:
200                                         tmp = win_count - entry->dccphrx_ccval;
201                                         if (tmp < 0)
202                                                 tmp += TFRC_WIN_COUNT_LIMIT;
203                                         if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
204                                                 /*
205                                                  * We have found a packet older
206                                                  * than one rtt remove the rest
207                                                  */
208                                                 step = 3;
209                                         } else /* OK, find next data packet */
210                                                 num_later = 1;
211                                         break;
212                                 case 3:
213                                         list_del_init(&entry->dccphrx_node);
214                                         dccp_rx_hist_entry_delete(hist, entry);
215                                         break;
216                                 }
217                         } else if (dccp_rx_hist_entry_data_packet(entry))
218                                 --num_later;
219                 }
220         }
221
222         return 0;
223 }
224
225 EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
226
227 u64 dccp_rx_hist_detect_loss(struct list_head *rx_list,
228                              struct list_head *li_list, u8 *win_loss)
229 {
230         struct dccp_rx_hist_entry *entry, *next, *packet;
231         struct dccp_rx_hist_entry *a_loss = NULL;
232         struct dccp_rx_hist_entry *b_loss = NULL;
233         u64 seq_loss = DCCP_MAX_SEQNO + 1;
234         u8 num_later = TFRC_RECV_NUM_LATE_LOSS;
235
236         list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
237                 if (num_later == 0) {
238                         b_loss = entry;
239                         break;
240                 } else if (dccp_rx_hist_entry_data_packet(entry))
241                         --num_later;
242         }
243
244         if (b_loss == NULL)
245                 goto out;
246
247         num_later = 1;
248         list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
249                 if (num_later == 0) {
250                         a_loss = entry;
251                         break;
252                 } else if (dccp_rx_hist_entry_data_packet(entry))
253                         --num_later;
254         }
255
256         if (a_loss == NULL) {
257                 if (list_empty(li_list)) {
258                         /* no loss event have occured yet */
259                         LIMIT_NETDEBUG("%s: TODO: find a lost data packet by "
260                                        "comparing to initial seqno\n",
261                                        __FUNCTION__);
262                         goto out;
263                 } else {
264                         LIMIT_NETDEBUG("%s: Less than 4 data pkts in history!",
265                                        __FUNCTION__);
266                         goto out;
267                 }
268         }
269
270         /* Locate a lost data packet */
271         entry = packet = b_loss;
272         list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
273                 u64 delta = dccp_delta_seqno(entry->dccphrx_seqno,
274                                              packet->dccphrx_seqno);
275
276                 if (delta != 0) {
277                         if (dccp_rx_hist_entry_data_packet(packet))
278                                 --delta;
279                         /*
280                          * FIXME: check this, probably this % usage is because
281                          * in earlier drafts the ndp count was just 8 bits
282                          * long, but now it cam be up to 24 bits long.
283                          */
284 #if 0
285                         if (delta % DCCP_NDP_LIMIT !=
286                             (packet->dccphrx_ndp -
287                              entry->dccphrx_ndp) % DCCP_NDP_LIMIT)
288 #endif
289                         if (delta != packet->dccphrx_ndp - entry->dccphrx_ndp) {
290                                 seq_loss = entry->dccphrx_seqno;
291                                 dccp_inc_seqno(&seq_loss);
292                         }
293                 }
294                 packet = entry;
295                 if (packet == a_loss)
296                         break;
297         }
298 out:
299         if (seq_loss != DCCP_MAX_SEQNO + 1)
300                 *win_loss = a_loss->dccphrx_ccval;
301         else
302                 *win_loss = 0; /* Paranoia */
303
304         return seq_loss;
305 }
306
307 EXPORT_SYMBOL_GPL(dccp_rx_hist_detect_loss);
308
309 struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
310 {
311         struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
312         static const char dccp_tx_hist_mask[] = "tx_hist_%s";
313         char *slab_name;
314
315         if (hist == NULL)
316                 goto out;
317
318         slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
319                             GFP_ATOMIC);
320         if (slab_name == NULL)
321                 goto out_free_hist;
322
323         sprintf(slab_name, dccp_tx_hist_mask, name);
324         hist->dccptxh_slab = kmem_cache_create(slab_name,
325                                              sizeof(struct dccp_tx_hist_entry),
326                                                0, SLAB_HWCACHE_ALIGN,
327                                                NULL, NULL);
328         if (hist->dccptxh_slab == NULL)
329                 goto out_free_slab_name;
330 out:
331         return hist;
332 out_free_slab_name:
333         kfree(slab_name);
334 out_free_hist:
335         kfree(hist);
336         hist = NULL;
337         goto out;
338 }
339
340 EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
341
342 void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
343 {
344         const char* name = kmem_cache_name(hist->dccptxh_slab);
345
346         kmem_cache_destroy(hist->dccptxh_slab);
347         kfree(name);
348         kfree(hist);
349 }
350
351 EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
352
353 struct dccp_tx_hist_entry *
354         dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
355 {
356         struct dccp_tx_hist_entry *packet = NULL, *entry;
357
358         list_for_each_entry(entry, list, dccphtx_node)
359                 if (entry->dccphtx_seqno == seq) {
360                         packet = entry;
361                         break;
362                 }
363
364         return packet;
365 }
366
367 EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
368
369 void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
370                               struct list_head *list,
371                               struct dccp_tx_hist_entry *packet)
372 {
373         struct dccp_tx_hist_entry *next;
374
375         list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
376                 list_del_init(&packet->dccphtx_node);
377                 dccp_tx_hist_entry_delete(hist, packet);
378         }
379 }
380
381 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
382
383 void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
384 {
385         struct dccp_tx_hist_entry *entry, *next;
386
387         list_for_each_entry_safe(entry, next, list, dccphtx_node) {
388                 list_del_init(&entry->dccphtx_node);
389                 dccp_tx_hist_entry_delete(hist, entry);
390         }
391 }
392
393 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
394
395 MODULE_AUTHOR("Ian McDonald <iam4@cs.waikato.ac.nz>, "
396               "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
397 MODULE_DESCRIPTION("DCCP TFRC library");
398 MODULE_LICENSE("GPL");