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");