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