Pull bugfix into test branch
[linux-2.6] / 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 #include "packet_history.h"
40
41 /*
42  *      Transmitter History Routines
43  */
44 struct 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;
65 out:
66         return hist;
67 out_free_slab_name:
68         kfree(slab_name);
69 out_free_hist:
70         kfree(hist);
71         hist = NULL;
72         goto out;
73 }
74
75 EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
76
77 void 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
86 EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
87
88 struct 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
102 EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
103
104 void 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
114 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
115
116 void 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
128 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
129
130 /*
131  *      Receiver History Routines
132  */
133 struct 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;
154 out:
155         return hist;
156 out_free_slab_name:
157         kfree(slab_name);
158 out_free_hist:
159         kfree(hist);
160         hist = NULL;
161         goto out;
162 }
163
164 EXPORT_SYMBOL_GPL(dccp_rx_hist_new);
165
166 void 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
175 EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);
176
177 int 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
194 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
195 struct 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
210 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
211
212 void 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
282 EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
283
284 void 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
294 EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
295
296
297 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
298               "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
299 MODULE_DESCRIPTION("DCCP TFRC library");
300 MODULE_LICENSE("GPL");