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mac80211: handle protection mode, RIFS and ADDBA for HT IBSS
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* Follow 802.11n-2009 9.13.3.1 for protection mode and ADDBA
* Send ADDBA only to HT STAs - implement 11.5.1.1 partially

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Simon Wunderlich authored and John W. Linville committed Dec 6, 2011
1 parent 54858ee commit ff3cc5f
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Showing 3 changed files with 44 additions and 0 deletions.
21 changes: 21 additions & 0 deletions net/mac80211/agg-tx.c
Original file line number Diff line number Diff line change
Expand Up @@ -430,6 +430,27 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
return -EINVAL;
}

/*
* 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
* member of an IBSS, and has no other existing Block Ack agreement
* with the recipient STA, then the initiating STA shall transmit a
* Probe Request frame to the recipient STA and shall not transmit an
* ADDBA Request frame unless it receives a Probe Response frame
* from the recipient within dot11ADDBAFailureTimeout.
*
* The probe request mechanism for ADDBA is currently not implemented,
* but we only build up Block Ack session with HT STAs. This information
* is set when we receive a bss info from a probe response or a beacon.
*/
if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
!sta->sta.ht_cap.ht_supported) {
#ifdef CONFIG_MAC80211_HT_DEBUG
printk(KERN_DEBUG "BA request denied - IBSS STA %pM"
"does not advertise HT support\n", pubsta->addr);
#endif /* CONFIG_MAC80211_HT_DEBUG */
return -EINVAL;
}

spin_lock_bh(&sta->lock);

/* we have tried too many times, receiver does not want A-MPDU */
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18 changes: 18 additions & 0 deletions net/mac80211/ibss.c
Original file line number Diff line number Diff line change
Expand Up @@ -896,6 +896,7 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
struct cfg80211_ibss_params *params)
{
struct sk_buff *skb;
u32 changed = 0;

skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
36 /* bitrates */ +
Expand Down Expand Up @@ -951,6 +952,23 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
ieee80211_recalc_idle(sdata->local);
mutex_unlock(&sdata->local->mtx);

/*
* 802.11n-2009 9.13.3.1: In an IBSS, the HT Protection field is
* reserved, but an HT STA shall protect HT transmissions as though
* the HT Protection field were set to non-HT mixed mode.
*
* In an IBSS, the RIFS Mode field of the HT Operation element is
* also reserved, but an HT STA shall operate as though this field
* were set to 1.
*/

sdata->vif.bss_conf.ht_operation_mode |=
IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED
| IEEE80211_HT_PARAM_RIFS_MODE;

changed |= BSS_CHANGED_HT;
ieee80211_bss_info_change_notify(sdata, changed);

ieee80211_queue_work(&sdata->local->hw, &sdata->work);

return 0;
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5 changes: 5 additions & 0 deletions net/mac80211/util.c
Original file line number Diff line number Diff line change
Expand Up @@ -1587,6 +1587,11 @@ u8 *ieee80211_ie_build_ht_info(u8 *pos,
}
if (ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40)
ht_info->ht_param |= IEEE80211_HT_PARAM_CHAN_WIDTH_ANY;

/*
* Note: According to 802.11n-2009 9.13.3.1, HT Protection field and
* RIFS Mode are reserved in IBSS mode, therefore keep them at 0
*/
ht_info->operation_mode = 0x0000;
ht_info->stbc_param = 0x0000;

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