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linux/net/mac80211/rate.c

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/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/module.h>
#include "rate.h"
#include "ieee80211_i.h"
#include "debugfs.h"
struct rate_control_alg {
struct list_head list;
struct rate_control_ops *ops;
};
static LIST_HEAD(rate_ctrl_algs);
static DEFINE_MUTEX(rate_ctrl_mutex);
static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
module_param(ieee80211_default_rc_algo, charp, 0644);
MODULE_PARM_DESC(ieee80211_default_rc_algo,
"Default rate control algorithm for mac80211 to use");
int ieee80211_rate_control_register(struct rate_control_ops *ops)
{
struct rate_control_alg *alg;
if (!ops->name)
return -EINVAL;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (!strcmp(alg->ops->name, ops->name)) {
/* don't register an algorithm twice */
WARN_ON(1);
mutex_unlock(&rate_ctrl_mutex);
return -EALREADY;
}
}
alg = kzalloc(sizeof(*alg), GFP_KERNEL);
if (alg == NULL) {
mutex_unlock(&rate_ctrl_mutex);
return -ENOMEM;
}
alg->ops = ops;
list_add_tail(&alg->list, &rate_ctrl_algs);
mutex_unlock(&rate_ctrl_mutex);
return 0;
}
EXPORT_SYMBOL(ieee80211_rate_control_register);
void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
{
struct rate_control_alg *alg;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (alg->ops == ops) {
list_del(&alg->list);
kfree(alg);
break;
}
}
mutex_unlock(&rate_ctrl_mutex);
}
EXPORT_SYMBOL(ieee80211_rate_control_unregister);
static struct rate_control_ops *
ieee80211_try_rate_control_ops_get(const char *name)
{
struct rate_control_alg *alg;
struct rate_control_ops *ops = NULL;
if (!name)
return NULL;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (!strcmp(alg->ops->name, name))
if (try_module_get(alg->ops->module)) {
ops = alg->ops;
break;
}
}
mutex_unlock(&rate_ctrl_mutex);
return ops;
}
/* Get the rate control algorithm. */
static struct rate_control_ops *
ieee80211_rate_control_ops_get(const char *name)
{
struct rate_control_ops *ops;
const char *alg_name;
kparam_block_sysfs_write(ieee80211_default_rc_algo);
if (!name)
alg_name = ieee80211_default_rc_algo;
else
alg_name = name;
ops = ieee80211_try_rate_control_ops_get(alg_name);
if (!ops) {
request_module("rc80211_%s", alg_name);
ops = ieee80211_try_rate_control_ops_get(alg_name);
}
if (!ops && name)
/* try default if specific alg requested but not found */
ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
/* try built-in one if specific alg requested but not found */
if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
kparam_unblock_sysfs_write(ieee80211_default_rc_algo);
return ops;
}
static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
{
module_put(ops->module);
}
#ifdef CONFIG_MAC80211_DEBUGFS
static ssize_t rcname_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rate_control_ref *ref = file->private_data;
int len = strlen(ref->ops->name);
return simple_read_from_buffer(userbuf, count, ppos,
ref->ops->name, len);
}
static const struct file_operations rcname_ops = {
.read = rcname_read,
.open = simple_open,
.llseek = default_llseek,
};
#endif
static struct rate_control_ref *rate_control_alloc(const char *name,
struct ieee80211_local *local)
{
struct dentry *debugfsdir = NULL;
struct rate_control_ref *ref;
ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
if (!ref)
goto fail_ref;
ref->local = local;
ref->ops = ieee80211_rate_control_ops_get(name);
if (!ref->ops)
goto fail_ops;
#ifdef CONFIG_MAC80211_DEBUGFS
debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
local->debugfs.rcdir = debugfsdir;
debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
#endif
ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
if (!ref->priv)
goto fail_priv;
return ref;
fail_priv:
ieee80211_rate_control_ops_put(ref->ops);
fail_ops:
kfree(ref);
fail_ref:
return NULL;
}
static void rate_control_free(struct rate_control_ref *ctrl_ref)
{
ctrl_ref->ops->free(ctrl_ref->priv);
#ifdef CONFIG_MAC80211_DEBUGFS
debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
ctrl_ref->local->debugfs.rcdir = NULL;
#endif
ieee80211_rate_control_ops_put(ctrl_ref->ops);
kfree(ctrl_ref);
}
static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
{
struct sk_buff *skb = txrc->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
__le16 fc;
fc = hdr->frame_control;
return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
IEEE80211_TX_CTL_USE_MINRATE)) ||
!ieee80211_is_data(fc);
}
static void rc_send_low_broadcast(s8 *idx, u32 basic_rates,
struct ieee80211_supported_band *sband)
{
u8 i;
if (basic_rates == 0)
return; /* assume basic rates unknown and accept rate */
if (*idx < 0)
return;
if (basic_rates & (1 << *idx))
return; /* selected rate is a basic rate */
for (i = *idx + 1; i <= sband->n_bitrates; i++) {
if (basic_rates & (1 << i)) {
*idx = i;
return;
}
}
/* could not find a basic rate; use original selection */
}
static inline s8
rate_lowest_non_cck_index(struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta)
{
int i;
for (i = 0; i < sband->n_bitrates; i++) {
struct ieee80211_rate *srate = &sband->bitrates[i];
if ((srate->bitrate == 10) || (srate->bitrate == 20) ||
(srate->bitrate == 55) || (srate->bitrate == 110))
continue;
if (rate_supported(sta, sband->band, i))
return i;
}
/* No matching rate found */
return 0;
}
static void __rate_control_send_low(struct ieee80211_hw *hw,
struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta,
struct ieee80211_tx_info *info)
{
if ((sband->band != IEEE80211_BAND_2GHZ) ||
!(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
info->control.rates[0].idx = rate_lowest_index(sband, sta);
else
info->control.rates[0].idx =
rate_lowest_non_cck_index(sband, sta);
info->control.rates[0].count =
(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
1 : hw->max_rate_tries;
info->control.skip_table = 1;
}
bool rate_control_send_low(struct ieee80211_sta *sta,
void *priv_sta,
struct ieee80211_tx_rate_control *txrc)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
struct ieee80211_supported_band *sband = txrc->sband;
int mcast_rate;
if (!sta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
__rate_control_send_low(txrc->hw, sband, sta, info);
if (!sta && txrc->bss) {
mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
if (mcast_rate > 0) {
info->control.rates[0].idx = mcast_rate - 1;
return true;
}
rc_send_low_broadcast(&info->control.rates[0].idx,
txrc->bss_conf->basic_rates,
sband);
}
return true;
}
return false;
}
EXPORT_SYMBOL(rate_control_send_low);
static bool rate_idx_match_legacy_mask(struct ieee80211_tx_rate *rate,
int n_bitrates, u32 mask)
{
int j;
/* See whether the selected rate or anything below it is allowed. */
for (j = rate->idx; j >= 0; j--) {
if (mask & (1 << j)) {
/* Okay, found a suitable rate. Use it. */
rate->idx = j;
return true;
}
}
/* Try to find a higher rate that would be allowed */
for (j = rate->idx + 1; j < n_bitrates; j++) {
if (mask & (1 << j)) {
/* Okay, found a suitable rate. Use it. */
rate->idx = j;
return true;
}
}
return false;
}
static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
{
int i, j;
int ridx, rbit;
ridx = rate->idx / 8;
rbit = rate->idx % 8;
/* sanity check */
if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
return false;
/* See whether the selected rate or anything below it is allowed. */
for (i = ridx; i >= 0; i--) {
for (j = rbit; j >= 0; j--)
if (mcs_mask[i] & BIT(j)) {
rate->idx = i * 8 + j;
return true;
}
rbit = 7;
}
/* Try to find a higher rate that would be allowed */
ridx = (rate->idx + 1) / 8;
rbit = (rate->idx + 1) % 8;
for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
for (j = rbit; j < 8; j++)
if (mcs_mask[i] & BIT(j)) {
rate->idx = i * 8 + j;
return true;
}
rbit = 0;
}
return false;
}
static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
struct ieee80211_supported_band *sband,
enum nl80211_chan_width chan_width,
u32 mask,
u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
{
struct ieee80211_tx_rate alt_rate;
/* handle HT rates */
if (rate->flags & IEEE80211_TX_RC_MCS) {
if (rate_idx_match_mcs_mask(rate, mcs_mask))
return;
/* also try the legacy rates. */
alt_rate.idx = 0;
/* keep protection flags */
alt_rate.flags = rate->flags &
(IEEE80211_TX_RC_USE_RTS_CTS |
IEEE80211_TX_RC_USE_CTS_PROTECT |
IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
alt_rate.count = rate->count;
if (rate_idx_match_legacy_mask(&alt_rate,
sband->n_bitrates, mask)) {
*rate = alt_rate;
return;
}
} else {
/* handle legacy rates */
if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
return;
/* if HT BSS, and we handle a data frame, also try HT rates */
switch (chan_width) {
case NL80211_CHAN_WIDTH_20_NOHT:
case NL80211_CHAN_WIDTH_5:
case NL80211_CHAN_WIDTH_10:
return;
default:
break;
}
alt_rate.idx = 0;
/* keep protection flags */
alt_rate.flags = rate->flags &
(IEEE80211_TX_RC_USE_RTS_CTS |
IEEE80211_TX_RC_USE_CTS_PROTECT |
IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
alt_rate.count = rate->count;
alt_rate.flags |= IEEE80211_TX_RC_MCS;
if (chan_width == NL80211_CHAN_WIDTH_40)
alt_rate.flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
*rate = alt_rate;
return;
}
}
/*
* Uh.. No suitable rate exists. This should not really happen with
* sane TX rate mask configurations. However, should someone manage to
* configure supported rates and TX rate mask in incompatible way,
* allow the frame to be transmitted with whatever the rate control
* selected.
*/
}
static void rate_fixup_ratelist(struct ieee80211_vif *vif,
struct ieee80211_supported_band *sband,
struct ieee80211_tx_info *info,
struct ieee80211_tx_rate *rates,
int max_rates)
{
struct ieee80211_rate *rate;
bool inval = false;
int i;
/*
* Set up the RTS/CTS rate as the fastest basic rate
* that is not faster than the data rate unless there
* is no basic rate slower than the data rate, in which
* case we pick the slowest basic rate
*
* XXX: Should this check all retry rates?
*/
if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
u32 basic_rates = vif->bss_conf.basic_rates;
s8 baserate = basic_rates ? ffs(basic_rates - 1) : 0;
rate = &sband->bitrates[rates[0].idx];
for (i = 0; i < sband->n_bitrates; i++) {
/* must be a basic rate */
if (!(basic_rates & BIT(i)))
continue;
/* must not be faster than the data rate */
if (sband->bitrates[i].bitrate > rate->bitrate)
continue;
/* maximum */
if (sband->bitrates[baserate].bitrate <
sband->bitrates[i].bitrate)
baserate = i;
}
info->control.rts_cts_rate_idx = baserate;
}
for (i = 0; i < max_rates; i++) {
/*
* make sure there's no valid rate following
* an invalid one, just in case drivers don't
* take the API seriously to stop at -1.
*/
if (inval) {
rates[i].idx = -1;
continue;
}
if (rates[i].idx < 0) {
inval = true;
continue;
}
/*
* For now assume MCS is already set up correctly, this
* needs to be fixed.
*/
if (rates[i].flags & IEEE80211_TX_RC_MCS) {
WARN_ON(rates[i].idx > 76);
if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
info->control.use_cts_prot)
rates[i].flags |=
IEEE80211_TX_RC_USE_CTS_PROTECT;
continue;
}
if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
continue;
}
/* set up RTS protection if desired */
if (info->control.use_rts) {
rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
info->control.use_cts_prot = false;
}
/* RC is busted */
if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
rates[i].idx = -1;
continue;
}
rate = &sband->bitrates[rates[i].idx];
/* set up short preamble */
if (info->control.short_preamble &&
rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
/* set up G protection */
if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
info->control.use_cts_prot &&
rate->flags & IEEE80211_RATE_ERP_G)
rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
}
}
static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
struct ieee80211_tx_info *info,
struct ieee80211_tx_rate *rates,
int max_rates)
{
struct ieee80211_sta_rates *ratetbl = NULL;
int i;
if (sta && !info->control.skip_table)
ratetbl = rcu_dereference(sta->rates);
/* Fill remaining rate slots with data from the sta rate table. */
max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
for (i = 0; i < max_rates; i++) {
if (i < ARRAY_SIZE(info->control.rates) &&
info->control.rates[i].idx >= 0 &&
info->control.rates[i].count) {
if (rates != info->control.rates)
rates[i] = info->control.rates[i];
} else if (ratetbl) {
rates[i].idx = ratetbl->rate[i].idx;
rates[i].flags = ratetbl->rate[i].flags;
if (info->control.use_rts)
rates[i].count = ratetbl->rate[i].count_rts;
else if (info->control.use_cts_prot)
rates[i].count = ratetbl->rate[i].count_cts;
else
rates[i].count = ratetbl->rate[i].count;
} else {
rates[i].idx = -1;
rates[i].count = 0;
}
if (rates[i].idx < 0 || !rates[i].count)
break;
}
}
static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta *sta,
struct ieee80211_supported_band *sband,
struct ieee80211_tx_info *info,
struct ieee80211_tx_rate *rates,
int max_rates)
{
enum nl80211_chan_width chan_width;
u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
bool has_mcs_mask;
u32 mask;
int i;
/*
* Try to enforce the rateidx mask the user wanted. skip this if the
* default mask (allow all rates) is used to save some processing for
* the common case.
*/
mask = sdata->rc_rateidx_mask[info->band];
has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
return;
if (has_mcs_mask)
memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
sizeof(mcs_mask));
else
memset(mcs_mask, 0xff, sizeof(mcs_mask));
if (sta) {
/* Filter out rates that the STA does not support */
mask &= sta->supp_rates[info->band];
for (i = 0; i < sizeof(mcs_mask); i++)
mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
}
/*
* Make sure the rate index selected for each TX rate is
* included in the configured mask and change the rate indexes
* if needed.
*/
chan_width = sdata->vif.bss_conf.chandef.width;
for (i = 0; i < max_rates; i++) {
/* Skip invalid rates */
if (rates[i].idx < 0)
break;
rate_idx_match_mask(&rates[i], sband, chan_width, mask,
mcs_mask);
}
}
void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
struct ieee80211_sta *sta,
struct sk_buff *skb,
struct ieee80211_tx_rate *dest,
int max_rates)
{
struct ieee80211_sub_if_data *sdata;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_supported_band *sband;
rate_control_fill_sta_table(sta, info, dest, max_rates);
if (!vif)
return;
sdata = vif_to_sdata(vif);
sband = sdata->local->hw.wiphy->bands[info->band];
if (ieee80211_is_data(hdr->frame_control))
rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);
if (dest[0].idx < 0)
__rate_control_send_low(&sdata->local->hw, sband, sta, info);
if (sta)
rate_fixup_ratelist(vif, sband, info, dest, max_rates);
}
EXPORT_SYMBOL(ieee80211_get_tx_rates);
void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_tx_rate_control *txrc)
{
struct rate_control_ref *ref = sdata->local->rate_ctrl;
void *priv_sta = NULL;
struct ieee80211_sta *ista = NULL;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
int i;
if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
ista = &sta->sta;
priv_sta = sta->rate_ctrl_priv;
}
for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
info->control.rates[i].idx = -1;
info->control.rates[i].flags = 0;
info->control.rates[i].count = 0;
}
if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
return;
ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
return;
ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
info->control.rates,
ARRAY_SIZE(info->control.rates));
}
int rate_control_set_rates(struct ieee80211_hw *hw,
struct ieee80211_sta *pubsta,
struct ieee80211_sta_rates *rates)
{
struct ieee80211_sta_rates *old;
/*
* mac80211 guarantees that this function will not be called
* concurrently, so the following RCU access is safe, even without
* extra locking. This can not be checked easily, so we just set
* the condition to true.
*/
old = rcu_dereference_protected(pubsta->rates, true);
rcu_assign_pointer(pubsta->rates, rates);
if (old)
kfree_rcu(old, rcu_head);
return 0;
}
EXPORT_SYMBOL(rate_control_set_rates);
int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
const char *name)
{
struct rate_control_ref *ref;
ASSERT_RTNL();
if (local->open_count)
return -EBUSY;
if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
if (WARN_ON(!local->ops->set_rts_threshold))
return -EINVAL;
return 0;
}
ref = rate_control_alloc(name, local);
if (!ref) {
wiphy_warn(local->hw.wiphy,
"Failed to select rate control algorithm\n");
return -ENOENT;
}
WARN_ON(local->rate_ctrl);
local->rate_ctrl = ref;
wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
ref->ops->name);
return 0;
}
void rate_control_deinitialize(struct ieee80211_local *local)
{
struct rate_control_ref *ref;
ref = local->rate_ctrl;
if (!ref)
return;
local->rate_ctrl = NULL;
rate_control_free(ref);
}
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