/*
* net/dccp/packet_history.h
*
* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
*
* An implementation of the DCCP protocol
*
* This code has been developed by the University of Waikato WAND
* research group. For further information please see http://www.wand.net.nz/
* or e-mail Ian McDonald - iam4@cs.waikato.ac.nz
*
* This code also uses code from Lulea University, rereleased as GPL by its
* authors:
* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
*
* Changes to meet Linux coding standards, to make it meet latest ccid3 draft
* and to make it work as a loadable module in the DCCP stack written by
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
*
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/string.h>
#include "packet_history.h"
struct dccp_rx_hist *dccp_rx_hist_new(const char *name)
{
struct dccp_rx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
static const char dccp_rx_hist_mask[] = "rx_hist_%s";
char *slab_name;
if (hist == NULL)
goto out;
slab_name = kmalloc(strlen(name) + sizeof(dccp_rx_hist_mask) - 1,
GFP_ATOMIC);
if (slab_name == NULL)
goto out_free_hist;
sprintf(slab_name, dccp_rx_hist_mask, name);
hist->dccprxh_slab = kmem_cache_create(slab_name,
sizeof(struct dccp_rx_hist_entry),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (hist->dccprxh_slab == NULL)
goto out_free_slab_name;
out:
return hist;
out_free_slab_name:
kfree(slab_name);
out_free_hist:
kfree(hist);
hist = NULL;
goto out;
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_new);
void dccp_rx_hist_delete(struct dccp_rx_hist *hist)
{
const char* name = kmem_cache_name(hist->dccprxh_slab);
kmem_cache_destroy(hist->dccprxh_slab);
kfree(name);
kfree(hist);
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_delete);
void dccp_rx_hist_purge(struct dccp_rx_hist *hist, struct list_head *list)
{
struct dccp_rx_hist_entry *entry, *next;
list_for_each_entry_safe(entry, next, list, dccphrx_node) {
list_del_init(&entry->dccphrx_node);
kmem_cache_free(hist->dccprxh_slab, entry);
}
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_purge);
struct dccp_rx_hist_entry *
dccp_rx_hist_find_data_packet(const struct list_head *list)
{
struct dccp_rx_hist_entry *entry, *packet = NULL;
list_for_each_entry(entry, list, dccphrx_node)
if (entry->dccphrx_type == DCCP_PKT_DATA ||
entry->dccphrx_type == DCCP_PKT_DATAACK) {
packet = entry;
break;
}
return packet;
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_find_data_packet);
int dccp_rx_hist_add_packet(struct dccp_rx_hist *hist,
struct list_head *rx_list,
struct list_head *li_list,
struct dccp_rx_hist_entry *packet)
{
struct dccp_rx_hist_entry *entry, *next, *iter;
u8 num_later = 0;
iter = dccp_rx_hist_head(rx_list);
if (iter == NULL)
dccp_rx_hist_add_entry(rx_list, packet);
else {
const u64 seqno = packet->dccphrx_seqno;
if (after48(seqno, iter->dccphrx_seqno))
dccp_rx_hist_add_entry(rx_list, packet);
else {
if (dccp_rx_hist_entry_data_packet(iter))
num_later = 1;
list_for_each_entry_continue(iter, rx_list,
dccphrx_node) {
if (after48(seqno, iter->dccphrx_seqno)) {
dccp_rx_hist_add_entry(&iter->dccphrx_node,
packet);
goto trim_history;
}
if (dccp_rx_hist_entry_data_packet(iter))
num_later++;
if (num_later == TFRC_RECV_NUM_LATE_LOSS) {
dccp_rx_hist_entry_delete(hist, packet);
return 1;
}
}
if (num_later < TFRC_RECV_NUM_LATE_LOSS)
dccp_rx_hist_add_entry(rx_list, packet);
/*
* FIXME: else what? should we destroy the packet
* like above?
*/
}
}
trim_history:
/*
* Trim history (remove all packets after the NUM_LATE_LOSS + 1
* data packets)
*/
num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
if (!list_empty(li_list)) {
list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
if (num_later == 0) {
list_del_init(&entry->dccphrx_node);
dccp_rx_hist_entry_delete(hist, entry);
} else if (dccp_rx_hist_entry_data_packet(entry))
--num_later;
}
} else {
int step = 0;
u8 win_count = 0; /* Not needed, but lets shut up gcc */
int tmp;
/*
* We have no loss interval history so we need at least one
* rtt:s of data packets to approximate rtt.
*/
list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
if (num_later == 0) {
switch (step) {
case 0:
step = 1;
/* OK, find next data packet */
num_later = 1;
break;
case 1:
step = 2;
/* OK, find next data packet */
num_later = 1;
win_count = entry->dccphrx_ccval;
break;
case 2:
tmp = win_count - entry->dccphrx_ccval;
if (tmp < 0)
tmp += TFRC_WIN_COUNT_LIMIT;
if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
/*
* We have found a packet older
* than one rtt remove the rest
*/
step = 3;
} else /* OK, find next data packet */
num_later = 1;
break;
case 3:
list_del_init(&entry->dccphrx_node);
dccp_rx_hist_entry_delete(hist, entry);
break;
}
} else if (dccp_rx_hist_entry_data_packet(entry))
--num_later;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
u64 dccp_rx_hist_detect_loss(struct list_head *rx_list,
struct list_head *li_list, u8 *win_loss)
{
struct dccp_rx_hist_entry *entry, *next, *packet;
struct dccp_rx_hist_entry *a_loss = NULL;
struct dccp_rx_hist_entry *b_loss = NULL;
u64 seq_loss = DCCP_MAX_SEQNO + 1;
u8 num_later = TFRC_RECV_NUM_LATE_LOSS;
list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
if (num_later == 0) {
b_loss = entry;
break;
} else if (dccp_rx_hist_entry_data_packet(entry))
--num_later;
}
if (b_loss == NULL)
goto out;
num_later = 1;
list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
if (num_later == 0) {
a_loss = entry;
break;
} else if (dccp_rx_hist_entry_data_packet(entry))
--num_later;
}
if (a_loss == NULL) {
if (list_empty(li_list)) {
/* no loss event have occured yet */
LIMIT_NETDEBUG("%s: TODO: find a lost data packet by "
"comparing to initial seqno\n",
__FUNCTION__);
goto out;
} else {
LIMIT_NETDEBUG("%s: Less than 4 data pkts in history!",
__FUNCTION__);
goto out;
}
}
/* Locate a lost data packet */
entry = packet = b_loss;
list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
u64 delta = dccp_delta_seqno(entry->dccphrx_seqno,
packet->dccphrx_seqno);
if (delta != 0) {
if (dccp_rx_hist_entry_data_packet(packet))
--delta;
/*
* FIXME: check this, probably this % usage is because
* in earlier drafts the ndp count was just 8 bits
* long, but now it cam be up to 24 bits long.
*/
#if 0
if (delta % DCCP_NDP_LIMIT !=
(packet->dccphrx_ndp -
entry->dccphrx_ndp) % DCCP_NDP_LIMIT)
#endif
if (delta != packet->dccphrx_ndp - entry->dccphrx_ndp) {
seq_loss = entry->dccphrx_seqno;
dccp_inc_seqno(&seq_loss);
}
}
packet = entry;
if (packet == a_loss)
break;
}
out:
if (seq_loss != DCCP_MAX_SEQNO + 1)
*win_loss = a_loss->dccphrx_ccval;
else
*win_loss = 0; /* Paranoia */
return seq_loss;
}
EXPORT_SYMBOL_GPL(dccp_rx_hist_detect_loss);
struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
{
struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
static const char dccp_tx_hist_mask[] = "tx_hist_%s";
char *slab_name;
if (hist == NULL)
goto out;
slab_name = kmalloc(strlen(name) + sizeof(dccp_tx_hist_mask) - 1,
GFP_ATOMIC);
if (slab_name == NULL)
goto out_free_hist;
sprintf(slab_name, dccp_tx_hist_mask, name);
hist->dccptxh_slab = kmem_cache_create(slab_name,
sizeof(struct dccp_tx_hist_entry),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (hist->dccptxh_slab == NULL)
goto out_free_slab_name;
out:
return hist;
out_free_slab_name:
kfree(slab_name);
out_free_hist:
kfree(hist);
hist = NULL;
goto out;
}
EXPORT_SYMBOL_GPL(dccp_tx_hist_new);
void dccp_tx_hist_delete(struct dccp_tx_hist *hist)
{
const char* name = kmem_cache_name(hist->dccptxh_slab);
kmem_cache_destroy(hist->dccptxh_slab);
kfree(name);
kfree(hist);
}
EXPORT_SYMBOL_GPL(dccp_tx_hist_delete);
struct dccp_tx_hist_entry *
dccp_tx_hist_find_entry(const struct list_head *list, const u64 seq)
{
struct dccp_tx_hist_entry *packet = NULL, *entry;
list_for_each_entry(entry, list, dccphtx_node)
if (entry->dccphtx_seqno == seq) {
packet = entry;
break;
}
return packet;
}
EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
struct list_head *list,
struct dccp_tx_hist_entry *packet)
{
struct dccp_tx_hist_entry *next;
list_for_each_entry_safe_continue(packet, next, list, dccphtx_node) {
list_del_init(&packet->dccphtx_node);
dccp_tx_hist_entry_delete(hist, packet);
}
}
EXPORT_SYMBOL_GPL(dccp_tx_hist_purge_older);
void dccp_tx_hist_purge(struct dccp_tx_hist *hist, struct list_head *list)
{
struct dccp_tx_hist_entry *entry, *next;
list_for_each_entry_safe(entry, next, list, dccphtx_node) {
list_del_init(&entry->dccphtx_node);
dccp_tx_hist_entry_delete(hist, entry);
}
}
EXPORT_SYMBOL_GPL(dccp_tx_hist_purge);
MODULE_AUTHOR("Ian McDonald <iam4@cs.waikato.ac.nz>, "
"Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
MODULE_DESCRIPTION("DCCP TFRC library");
MODULE_LICENSE("GPL");
