git.oblomov.eu Git - linux-2.6/blob - 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");