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 void 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                             u64 nonloss_seqno)
 120 {
 121         struct dccp_rx_hist_entry *entry, *next;
 122         u8 num_later = 0;
 123
 124         list_add(&packet->dccphrx_node, rx_list);
 125
 126         num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
 127
 128         if (!list_empty(li_list)) {
 129                 list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
 130                         if (num_later == 0) {
 131                                 if (after48(nonloss_seqno,
 132                                    entry->dccphrx_seqno)) {
 133                                         list_del_init(&entry->dccphrx_node);
 134                                         dccp_rx_hist_entry_delete(hist, entry);
 135                                 }
 136                         } else if (dccp_rx_hist_entry_data_packet(entry))
 137                                 --num_later;
 138                 }
 139         } else {
 140                 int step = 0;
 141                 u8 win_count = 0; /* Not needed, but lets shut up gcc */
 142                 int tmp;
 143                 /*
 144                  * We have no loss interval history so we need at least one
 145                  * rtt:s of data packets to approximate rtt.
 146                  */
 147                 list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
 148                         if (num_later == 0) {
 149                                 switch (step) {
 150                                 case 0:
 151                                         step = 1;
 152                                         /* OK, find next data packet */
 153                                         num_later = 1;
 154                                         break;
 155                                 case 1:
 156                                         step = 2;
 157                                         /* OK, find next data packet */
 158                                         num_later = 1;
 159                                         win_count = entry->dccphrx_ccval;
 160                                         break;
 161                                 case 2:
 162                                         tmp = win_count - entry->dccphrx_ccval;
 163                                         if (tmp < 0)
 164                                                 tmp += TFRC_WIN_COUNT_LIMIT;
 165                                         if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
 166                                                 /*
 167                                                  * We have found a packet older
 168                                                  * than one rtt remove the rest
 169                                                  */
 170                                                 step = 3;
 171                                         } else /* OK, find next data packet */
 172                                                 num_later = 1;
 173                                         break;
 174                                 case 3:
 175                                         list_del_init(&entry->dccphrx_node);
 176                                         dccp_rx_hist_entry_delete(hist, entry);
 177                                         break;
 178                                 }
 179                         } else if (dccp_rx_hist_entry_data_packet(entry))
 180                                 --num_later;
 181                 }
 182         }
 183 }
 184
 185 EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
 186
 187 struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
 188 {
 189         struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
 190         static const char dccp_tx_hist_mask[] = "tx_hist_%s";
 191         char *slab_name;
 192
 193         if (hist == NULL)
 194                 goto out;
 195
 196         slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
 197                             GFP_ATOMIC);
 198         if (slab_name == NULL)
 199                 goto out_free_hist;
 200
 201         sprintf(slab_name, dccp_tx_hist_mask, name);
 202         hist->dccptxh_slab = kmem_cache_create(slab_name,
 203                                              sizeof(struct dccp_tx_hist_entry),
 204                                                0, SLAB_HWCACHE_ALIGN,
 205                                                NULL, NULL);
 206         if (hist->dccptxh_slab == NULL)
 207                 goto out_free_slab_name;
 208 out:
 209         return hist;
 210 out_free_slab_name:
 211         kfree(slab_name);
 212 out_free_hist:
 213         kfree(hist);
 214         hist = NULL;
 215         goto out;
 216 }
 217
 218 EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
 219
 220 void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
 221 {
 222         const char* name = kmem_cache_name(hist->dccptxh_slab);
 223
 224         kmem_cache_destroy(hist->dccptxh_slab);
 225         kfree(name);
 226         kfree(hist);
 227 }
 228
 229 EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
 230
 231 struct dccp_tx_hist_entry *
 232         dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
 233 {
 234         struct dccp_tx_hist_entry *packet = NULL, *entry;
 235
 236         list_for_each_entry(entry, list, dccphtx_node)
 237                 if (entry->dccphtx_seqno == seq) {
 238                         packet = entry;
 239                         break;
 240                 }
 241
 242         return packet;
 243 }
 244
 245 EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
 246
 247 int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
 248    u8 *ccval)
 249 {
 250         struct dccp_rx_hist_entry *packet = NULL, *entry;
 251
 252         list_for_each_entry(entry, list, dccphrx_node)
 253                 if (entry->dccphrx_seqno == seq) {
 254                         packet = entry;
 255                         break;
 256                 }
 257
 258         if (packet)
 259                 *ccval = packet->dccphrx_ccval;
 260
 261         return packet != NULL;
 262 }
 263
 264 EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
 265
 266 void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
 267                               struct list_head *list,
 268                               struct dccp_tx_hist_entry *packet)
 269 {
 270         struct dccp_tx_hist_entry *next;
 271
 272         list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
 273                 list_del_init(&packet->dccphtx_node);
 274                 dccp_tx_hist_entry_delete(hist, packet);
 275         }
 276 }
 277
 278 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
 279
 280 void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
 281 {
 282         struct dccp_tx_hist_entry *entry, *next;
 283
 284         list_for_each_entry_safe(entry, next, list, dccphtx_node) {
 285                 list_del_init(&entry->dccphtx_node);
 286                 dccp_tx_hist_entry_delete(hist, entry);
 287         }
 288 }
 289
 290 EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
 291
 292 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
 293               "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
 294 MODULE_DESCRIPTION("DCCP TFRC library");
 295 MODULE_LICENSE("GPL");