mac80211: send (QoS) Null if no buffered frames
For PS-poll, there's a possible race between us expiring a frame and the station polling for it -- send it a null frame in that case. For uAPSD, the standard says that we have to send a frame in each SP, so send null if we don't have any other frames. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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47086fc51a
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ce662b44ce
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@ -1272,6 +1272,7 @@ void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int ke
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struct ieee80211_hdr *hdr, const u8 *tsc,
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gfp_t gfp);
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void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata);
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void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb);
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void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb);
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void ieee802_11_parse_elems(u8 *start, size_t len,
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struct ieee802_11_elems *elems);
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@ -24,6 +24,7 @@
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#include "sta_info.h"
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#include "debugfs_sta.h"
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#include "mesh.h"
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#include "wme.h"
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/**
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* DOC: STA information lifetime rules
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@ -247,10 +248,16 @@ static void sta_unblock(struct work_struct *wk)
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ieee80211_sta_ps_deliver_wakeup(sta);
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else if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL)) {
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clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
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local_bh_disable();
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ieee80211_sta_ps_deliver_poll_response(sta);
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local_bh_enable();
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} else if (test_and_clear_sta_flags(sta, WLAN_STA_UAPSD)) {
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clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
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local_bh_disable();
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ieee80211_sta_ps_deliver_uapsd(sta);
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local_bh_enable();
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} else
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clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
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}
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@ -1157,6 +1164,70 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
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#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
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}
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static void ieee80211_send_null_response(struct ieee80211_sub_if_data *sdata,
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struct sta_info *sta, int tid,
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bool uapsd)
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{
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struct ieee80211_local *local = sdata->local;
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struct ieee80211_qos_hdr *nullfunc;
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struct sk_buff *skb;
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int size = sizeof(*nullfunc);
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__le16 fc;
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bool qos = test_sta_flags(sta, WLAN_STA_WME);
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struct ieee80211_tx_info *info;
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if (qos) {
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fc = cpu_to_le16(IEEE80211_FTYPE_DATA |
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IEEE80211_STYPE_QOS_NULLFUNC |
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IEEE80211_FCTL_FROMDS);
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} else {
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size -= 2;
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fc = cpu_to_le16(IEEE80211_FTYPE_DATA |
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IEEE80211_STYPE_NULLFUNC |
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IEEE80211_FCTL_FROMDS);
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}
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skb = dev_alloc_skb(local->hw.extra_tx_headroom + size);
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if (!skb)
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return;
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skb_reserve(skb, local->hw.extra_tx_headroom);
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nullfunc = (void *) skb_put(skb, size);
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nullfunc->frame_control = fc;
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nullfunc->duration_id = 0;
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memcpy(nullfunc->addr1, sta->sta.addr, ETH_ALEN);
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memcpy(nullfunc->addr2, sdata->vif.addr, ETH_ALEN);
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memcpy(nullfunc->addr3, sdata->vif.addr, ETH_ALEN);
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if (qos) {
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skb->priority = tid;
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skb_set_queue_mapping(skb, ieee802_1d_to_ac[tid]);
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nullfunc->qos_ctrl = cpu_to_le16(tid);
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if (uapsd)
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nullfunc->qos_ctrl |=
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cpu_to_le16(IEEE80211_QOS_CTL_EOSP);
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}
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info = IEEE80211_SKB_CB(skb);
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/*
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* Tell TX path to send this frame even though the
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* STA may still remain is PS mode after this frame
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* exchange.
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*/
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info->flags |= IEEE80211_TX_CTL_POLL_RESPONSE;
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if (uapsd)
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info->flags |= IEEE80211_TX_STATUS_EOSP |
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IEEE80211_TX_CTL_REQ_TX_STATUS;
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ieee80211_xmit(sdata, skb);
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}
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static void
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ieee80211_sta_ps_deliver_response(struct sta_info *sta,
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int n_frames, u8 ignored_acs,
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@ -1228,19 +1299,28 @@ ieee80211_sta_ps_deliver_response(struct sta_info *sta,
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}
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if (!found) {
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#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
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/*
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* FIXME: This can be the result of a race condition between
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* us expiring a frame and the station polling for it.
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* Should we send it a null-func frame indicating we
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* have nothing buffered for it?
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*/
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if (reason == IEEE80211_FRAME_RELEASE_PSPOLL)
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printk(KERN_DEBUG "%s: STA %pM sent PS Poll even "
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"though there are no buffered frames for it\n",
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sdata->name, sta->sta.addr);
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#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
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int tid;
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/*
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* For PS-Poll, this can only happen due to a race condition
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* when we set the TIM bit and the station notices it, but
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* before it can poll for the frame we expire it.
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*
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* For uAPSD, this is said in the standard (11.2.1.5 h):
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* At each unscheduled SP for a non-AP STA, the AP shall
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* attempt to transmit at least one MSDU or MMPDU, but no
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* more than the value specified in the Max SP Length field
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* in the QoS Capability element from delivery-enabled ACs,
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* that are destined for the non-AP STA.
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*
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* Since we have no other MSDU/MMPDU, transmit a QoS null frame.
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*/
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/* This will evaluate to 1, 3, 5 or 7. */
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tid = 7 - ((ffs(~ignored_acs) - 1) << 1);
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ieee80211_send_null_response(sdata, sta, tid,
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reason == IEEE80211_FRAME_RELEASE_UAPSD);
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return;
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}
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@ -1520,8 +1520,7 @@ static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
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return 0;
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}
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static void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
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struct sk_buff *skb)
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void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
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{
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struct ieee80211_local *local = sdata->local;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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