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mac80211: fix timing for 5 MHz and 10 MHz channels

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according to IEEE 802.11-2012 section 18, various timings change
when using 5 MHz and 10 MHz. Reflect this by using a "shift" when
calculating durations.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
This commit is contained in:
Simon Wunderlich 2013-07-08 16:55:51 +02:00 committed by Johannes Berg
parent 3de805cf96
commit 438b61b770
5 changed files with 90 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
net/mac80211/ieee80211_i.h
View File

@ -812,6 +812,34 @@ ieee80211_get_sdata_band(struct ieee80211_sub_if_data *sdata)
return band;
}
static inline int
ieee80211_chandef_get_shift(struct cfg80211_chan_def *chandef)
{
switch (chandef->width) {
case NL80211_CHAN_WIDTH_5:
return 2;
case NL80211_CHAN_WIDTH_10:
return 1;
default:
return 0;
}
}
static inline int
ieee80211_vif_get_shift(struct ieee80211_vif *vif)
{
struct ieee80211_chanctx_conf *chanctx_conf;
int shift = 0;
rcu_read_lock();
chanctx_conf = rcu_dereference(vif->chanctx_conf);
if (chanctx_conf)
shift = ieee80211_chandef_get_shift(&chanctx_conf->def);
rcu_read_unlock();
return shift;
}
enum sdata_queue_type {
IEEE80211_SDATA_QUEUE_TYPE_FRAME = 0,
IEEE80211_SDATA_QUEUE_AGG_START = 1,
@ -1468,7 +1496,8 @@ extern void *mac80211_wiphy_privid; /* for wiphy privid */
u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
enum nl80211_iftype type);
int ieee80211_frame_duration(enum ieee80211_band band, size_t len,
int rate, int erp, int short_preamble);
int rate, int erp, int short_preamble,
int shift);
void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int keyidx,
struct ieee80211_hdr *hdr, const u8 *tsc,
gfp_t gfp);

30
net/mac80211/rc80211_minstrel.c
View File

@ -382,14 +382,18 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
static void
calc_rate_durations(enum ieee80211_band band,
struct minstrel_rate *d,
struct ieee80211_rate *rate)
struct ieee80211_rate *rate,
struct cfg80211_chan_def *chandef)
{
int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
int shift = ieee80211_chandef_get_shift(chandef);
d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
rate->bitrate, erp, 1);
DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
shift);
d->ack_time = ieee80211_frame_duration(band, 10,
rate->bitrate, erp, 1);
DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1,
shift);
}
static void
@ -425,14 +429,17 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_rate *ctl_rate;
unsigned int i, n = 0;
unsigned int t_slot = 9; /* FIXME: get real slot time */
u32 rate_flags;
mi->sta = sta;
mi->lowest_rix = rate_lowest_index(sband, sta);
ctl_rate = &sband->bitrates[mi->lowest_rix];
mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
ctl_rate->bitrate,
!!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1);
!!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1,
ieee80211_chandef_get_shift(chandef));
rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate));
mi->max_prob_rate = 0;
@ -441,15 +448,22 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
unsigned int tx_time_single;
unsigned int cw = mp->cw_min;
int shift;
if (!rate_supported(sta, sband->band, i))
continue;
if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
continue;
n++;
memset(mr, 0, sizeof(*mr));
mr->rix = i;
mr->bitrate = sband->bitrates[i].bitrate / 5;
calc_rate_durations(sband->band, mr, &sband->bitrates[i]);
shift = ieee80211_chandef_get_shift(chandef);
mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
(1 << shift) * 5);
calc_rate_durations(sband->band, mr, &sband->bitrates[i],
chandef);
/* calculate maximum number of retransmissions before
* fallback (based on maximum segment size) */
@ -547,6 +561,7 @@ minstrel_init_cck_rates(struct minstrel_priv *mp)
{
static const int bitrates[4] = { 10, 20, 55, 110 };
struct ieee80211_supported_band *sband;
u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef);
int i, j;
sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];
@ -559,6 +574,9 @@ minstrel_init_cck_rates(struct minstrel_priv *mp)
if (rate->flags & IEEE80211_RATE_ERP_G)
continue;
if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
continue;
for (j = 0; j < ARRAY_SIZE(bitrates); j++) {
if (rate->bitrate != bitrates[j])
continue;

5
net/mac80211/rc80211_minstrel_ht.c
View File

@ -862,8 +862,9 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
mi->sta = sta;
mi->stats_update = jiffies;
ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1);
mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur;
ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0);
mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0);
mi->overhead += ack_dur;
mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);

10
net/mac80211/tx.c
View File

@ -40,7 +40,7 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
struct sk_buff *skb, int group_addr,
int next_frag_len)
{
int rate, mrate, erp, dur, i;
int rate, mrate, erp, dur, i, shift;
struct ieee80211_rate *txrate;
struct ieee80211_local *local = tx->local;
struct ieee80211_supported_band *sband;
@ -153,6 +153,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
rate = mrate;
}
shift = ieee80211_vif_get_shift(&tx->sdata->vif);
/* Don't calculate ACKs for QoS Frames with NoAck Policy set */
if (ieee80211_is_data_qos(hdr->frame_control) &&
*(ieee80211_get_qos_ctl(hdr)) & IEEE80211_QOS_CTL_ACK_POLICY_NOACK)
@ -162,7 +164,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
* (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up
* to closest integer */
dur = ieee80211_frame_duration(sband->band, 10, rate, erp,
tx->sdata->vif.bss_conf.use_short_preamble);
tx->sdata->vif.bss_conf.use_short_preamble,
shift);
if (next_frag_len) {
/* Frame is fragmented: duration increases with time needed to
@ -171,7 +174,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
/* next fragment */
dur += ieee80211_frame_duration(sband->band, next_frag_len,
txrate->bitrate, erp,
tx->sdata->vif.bss_conf.use_short_preamble);
tx->sdata->vif.bss_conf.use_short_preamble,
shift);
}
return cpu_to_le16(dur);

39
net/mac80211/util.c
View File

@ -107,7 +107,8 @@ void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
}
int ieee80211_frame_duration(enum ieee80211_band band, size_t len,
int rate, int erp, int short_preamble)
int rate, int erp, int short_preamble,
int shift)
{
int dur;
@ -118,6 +119,9 @@ int ieee80211_frame_duration(enum ieee80211_band band, size_t len,
*
* rate is in 100 kbps, so divident is multiplied by 10 in the
* DIV_ROUND_UP() operations.
*
* shift may be 2 for 5 MHz channels or 1 for 10 MHz channels, and
* is assumed to be 0 otherwise.
*/
if (band == IEEE80211_BAND_5GHZ || erp) {
@ -130,15 +134,21 @@ int ieee80211_frame_duration(enum ieee80211_band band, size_t len,
* TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
*
* T_SYM = 4 usec
* 802.11a - 17.5.2: aSIFSTime = 16 usec
* 802.11a - 18.5.2: aSIFSTime = 16 usec
* 802.11g - 19.8.4: aSIFSTime = 10 usec +
* signal ext = 6 usec
*/
dur = 16; /* SIFS + signal ext */
dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
dur += 16; /* IEEE 802.11-2012 18.3.2.4: T_PREAMBLE = 16 usec */
dur += 4; /* IEEE 802.11-2012 18.3.2.4: T_SIGNAL = 4 usec */
dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
4 * rate); /* T_SYM x N_SYM */
/* IEEE 802.11-2012 18.3.2.4: all values above are:
* * times 4 for 5 MHz
* * times 2 for 10 MHz
*/
dur *= 1 << shift;
} else {
/*
* 802.11b or 802.11g with 802.11b compatibility:
@ -168,7 +178,7 @@ __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
{
struct ieee80211_sub_if_data *sdata;
u16 dur;
int erp;
int erp, shift = 0;
bool short_preamble = false;
erp = 0;
@ -177,10 +187,11 @@ __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
short_preamble = sdata->vif.bss_conf.use_short_preamble;
if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
erp = rate->flags & IEEE80211_RATE_ERP_G;
shift = ieee80211_vif_get_shift(vif);
}
dur = ieee80211_frame_duration(band, frame_len, rate->bitrate, erp,
short_preamble);
short_preamble, shift);
return cpu_to_le16(dur);
}
@ -194,7 +205,7 @@ __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
struct ieee80211_rate *rate;
struct ieee80211_sub_if_data *sdata;
bool short_preamble;
int erp;
int erp, shift = 0;
u16 dur;
struct ieee80211_supported_band *sband;
@ -210,17 +221,18 @@ __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
short_preamble = sdata->vif.bss_conf.use_short_preamble;
if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
erp = rate->flags & IEEE80211_RATE_ERP_G;
shift = ieee80211_vif_get_shift(vif);
}
/* CTS duration */
dur = ieee80211_frame_duration(sband->band, 10, rate->bitrate,
erp, short_preamble);
erp, short_preamble, shift);
/* Data frame duration */
dur += ieee80211_frame_duration(sband->band, frame_len, rate->bitrate,
erp, short_preamble);
erp, short_preamble, shift);
/* ACK duration */
dur += ieee80211_frame_duration(sband->band, 10, rate->bitrate,
erp, short_preamble);
erp, short_preamble, shift);
return cpu_to_le16(dur);
}
@ -235,7 +247,7 @@ __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
struct ieee80211_rate *rate;
struct ieee80211_sub_if_data *sdata;
bool short_preamble;
int erp;
int erp, shift = 0;
u16 dur;
struct ieee80211_supported_band *sband;
@ -250,15 +262,16 @@ __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
short_preamble = sdata->vif.bss_conf.use_short_preamble;
if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
erp = rate->flags & IEEE80211_RATE_ERP_G;
shift = ieee80211_vif_get_shift(vif);
}
/* Data frame duration */
dur = ieee80211_frame_duration(sband->band, frame_len, rate->bitrate,
erp, short_preamble);
erp, short_preamble, shift);
if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
/* ACK duration */
dur += ieee80211_frame_duration(sband->band, 10, rate->bitrate,
erp, short_preamble);
erp, short_preamble, shift);
}
return cpu_to_le16(dur);