mac80211: fix timing for 5 MHz and 10 MHz channels

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>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 683751a1ecebef59701a115e7b13ca20194602bf..338e7ca21ea5dc0e7784ff7e4bbd71a1fe36c9f5 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -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);

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index 5b25966add10be9d6738e7d329e520af1a6f1e33..a507376d53168558fa9f48924974b89c699f0b6c 100644 (file)
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -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;

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 52562973fbd177ab73bd9e26f2827114d4acbdb4..7475a7a337974adb228f720f3aac397ca685f618 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -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);

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 4105d0ca963e25dfdd558e30c48274277e5ad2df..3523daa0b15c1537daff9351655844b64bf13713 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -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);

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 22654452a56157b44835f97efacdf2e8960ee5bc..61856e17a1e49ff1f52d379feb9faac796d4dba2 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -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);