Merge tag 'for-v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux...

[mirror_ubuntu-artful-kernel.git] / net / mac80211 / status.c

/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 * Copyright 2008-2010  Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 *
 * 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/export.h>
#include <linux/etherdevice.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "mesh.h"
#include "led.h"
#include "wme.h"


void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
                                 struct sk_buff *skb)
{
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        int tmp;

        skb->pkt_type = IEEE80211_TX_STATUS_MSG;
        skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
                       &local->skb_queue : &local->skb_queue_unreliable, skb);
        tmp = skb_queue_len(&local->skb_queue) +
                skb_queue_len(&local->skb_queue_unreliable);
        while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
               (skb = skb_dequeue(&local->skb_queue_unreliable))) {
                ieee80211_free_txskb(hw, skb);
                tmp--;
                I802_DEBUG_INC(local->tx_status_drop);
        }
        tasklet_schedule(&local->tasklet);
}
EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);

static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
                                            struct sta_info *sta,
                                            struct sk_buff *skb)
{
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (void *)skb->data;
        int ac;

        if (info->flags & (IEEE80211_TX_CTL_NO_PS_BUFFER |
                           IEEE80211_TX_CTL_AMPDU)) {
                ieee80211_free_txskb(&local->hw, skb);
                return;
        }

        /*
         * This skb 'survived' a round-trip through the driver, and
         * hopefully the driver didn't mangle it too badly. However,
         * we can definitely not rely on the control information
         * being correct. Clear it so we don't get junk there, and
         * indicate that it needs new processing, but must not be
         * modified/encrypted again.
         */
        memset(&info->control, 0, sizeof(info->control));

        info->control.jiffies = jiffies;
        info->control.vif = &sta->sdata->vif;
        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
                       IEEE80211_TX_INTFL_RETRANSMISSION;
        info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;

        sta->status_stats.filtered++;

        /*
         * Clear more-data bit on filtered frames, it might be set
         * but later frames might time out so it might have to be
         * clear again ... It's all rather unlikely (this frame
         * should time out first, right?) but let's not confuse
         * peers unnecessarily.
         */
        if (hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_MOREDATA))
                hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_MOREDATA);

        if (ieee80211_is_data_qos(hdr->frame_control)) {
                u8 *p = ieee80211_get_qos_ctl(hdr);
                int tid = *p & IEEE80211_QOS_CTL_TID_MASK;

                /*
                 * Clear EOSP if set, this could happen e.g.
                 * if an absence period (us being a P2P GO)
                 * shortens the SP.
                 */
                if (*p & IEEE80211_QOS_CTL_EOSP)
                        *p &= ~IEEE80211_QOS_CTL_EOSP;
                ac = ieee80211_ac_from_tid(tid);
        } else {
                ac = IEEE80211_AC_BE;
        }

        /*
         * Clear the TX filter mask for this STA when sending the next
         * packet. If the STA went to power save mode, this will happen
         * when it wakes up for the next time.
         */
        set_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT);
        ieee80211_clear_fast_xmit(sta);

        /*
         * This code races in the following way:
         *
         *  (1) STA sends frame indicating it will go to sleep and does so
         *  (2) hardware/firmware adds STA to filter list, passes frame up
         *  (3) hardware/firmware processes TX fifo and suppresses a frame
         *  (4) we get TX status before having processed the frame and
         *      knowing that the STA has gone to sleep.
         *
         * This is actually quite unlikely even when both those events are
         * processed from interrupts coming in quickly after one another or
         * even at the same time because we queue both TX status events and
         * RX frames to be processed by a tasklet and process them in the
         * same order that they were received or TX status last. Hence, there
         * is no race as long as the frame RX is processed before the next TX
         * status, which drivers can ensure, see below.
         *
         * Note that this can only happen if the hardware or firmware can
         * actually add STAs to the filter list, if this is done by the
         * driver in response to set_tim() (which will only reduce the race
         * this whole filtering tries to solve, not completely solve it)
         * this situation cannot happen.
         *
         * To completely solve this race drivers need to make sure that they
         *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
         *      functions and
         *  (b) always process RX events before TX status events if ordering
         *      can be unknown, for example with different interrupt status
         *      bits.
         *  (c) if PS mode transitions are manual (i.e. the flag
         *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
         *      changes before calling TX status events if ordering can be
         *      unknown.
         */
        if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
            skb_queue_len(&sta->tx_filtered[ac]) < STA_MAX_TX_BUFFER) {
                skb_queue_tail(&sta->tx_filtered[ac], skb);
                sta_info_recalc_tim(sta);

                if (!timer_pending(&local->sta_cleanup))
                        mod_timer(&local->sta_cleanup,
                                  round_jiffies(jiffies +
                                                STA_INFO_CLEANUP_INTERVAL));
                return;
        }

        if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
            !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
                /* Software retry the packet once */
                info->flags |= IEEE80211_TX_INTFL_RETRIED;
                ieee80211_add_pending_skb(local, skb);
                return;
        }

        ps_dbg_ratelimited(sta->sdata,
                           "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
                           skb_queue_len(&sta->tx_filtered[ac]),
                           !!test_sta_flag(sta, WLAN_STA_PS_STA), jiffies);
        ieee80211_free_txskb(&local->hw, skb);
}

static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
{
        struct tid_ampdu_tx *tid_tx;

        tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
        if (!tid_tx || !tid_tx->bar_pending)
                return;

        tid_tx->bar_pending = false;
        ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
}

static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
{
        struct ieee80211_mgmt *mgmt = (void *) skb->data;
        struct ieee80211_local *local = sta->local;
        struct ieee80211_sub_if_data *sdata = sta->sdata;

        if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
                sta->status_stats.last_ack = jiffies;

        if (ieee80211_is_data_qos(mgmt->frame_control)) {
                struct ieee80211_hdr *hdr = (void *) skb->data;
                u8 *qc = ieee80211_get_qos_ctl(hdr);
                u16 tid = qc[0] & 0xf;

                ieee80211_check_pending_bar(sta, hdr->addr1, tid);
        }

        if (ieee80211_is_action(mgmt->frame_control) &&
            !ieee80211_has_protected(mgmt->frame_control) &&
            mgmt->u.action.category == WLAN_CATEGORY_HT &&
            mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS &&
            ieee80211_sdata_running(sdata)) {
                enum ieee80211_smps_mode smps_mode;

                switch (mgmt->u.action.u.ht_smps.smps_control) {
                case WLAN_HT_SMPS_CONTROL_DYNAMIC:
                        smps_mode = IEEE80211_SMPS_DYNAMIC;
                        break;
                case WLAN_HT_SMPS_CONTROL_STATIC:
                        smps_mode = IEEE80211_SMPS_STATIC;
                        break;
                case WLAN_HT_SMPS_CONTROL_DISABLED:
                default: /* shouldn't happen since we don't send that */
                        smps_mode = IEEE80211_SMPS_OFF;
                        break;
                }

                if (sdata->vif.type == NL80211_IFTYPE_STATION) {
                        /*
                         * This update looks racy, but isn't -- if we come
                         * here we've definitely got a station that we're
                         * talking to, and on a managed interface that can
                         * only be the AP. And the only other place updating
                         * this variable in managed mode is before association.
                         */
                        sdata->smps_mode = smps_mode;
                        ieee80211_queue_work(&local->hw, &sdata->recalc_smps);
                } else if (sdata->vif.type == NL80211_IFTYPE_AP ||
                           sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                        sta->known_smps_mode = smps_mode;
                }
        }
}

static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
{
        struct tid_ampdu_tx *tid_tx;

        tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
        if (!tid_tx)
                return;

        tid_tx->failed_bar_ssn = ssn;
        tid_tx->bar_pending = true;
}

static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
{
        int len = sizeof(struct ieee80211_radiotap_header);

        /* IEEE80211_RADIOTAP_RATE rate */
        if (info->status.rates[0].idx >= 0 &&
            !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
                                             IEEE80211_TX_RC_VHT_MCS)))
                len += 2;

        /* IEEE80211_RADIOTAP_TX_FLAGS */
        len += 2;

        /* IEEE80211_RADIOTAP_DATA_RETRIES */
        len += 1;

        /* IEEE80211_RADIOTAP_MCS
         * IEEE80211_RADIOTAP_VHT */
        if (info->status.rates[0].idx >= 0) {
                if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
                        len += 3;
                else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS)
                        len = ALIGN(len, 2) + 12;
        }

        return len;
}

static void
ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
                                 struct ieee80211_supported_band *sband,
                                 struct sk_buff *skb, int retry_count,
                                 int rtap_len, int shift)
{
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_radiotap_header *rthdr;
        unsigned char *pos;
        u16 txflags;

        rthdr = (struct ieee80211_radiotap_header *) skb_push(skb, rtap_len);

        memset(rthdr, 0, rtap_len);
        rthdr->it_len = cpu_to_le16(rtap_len);
        rthdr->it_present =
                cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
                            (1 << IEEE80211_RADIOTAP_DATA_RETRIES));
        pos = (unsigned char *)(rthdr + 1);

        /*
         * XXX: Once radiotap gets the bitmap reset thing the vendor
         *      extensions proposal contains, we can actually report
         *      the whole set of tries we did.
         */

        /* IEEE80211_RADIOTAP_RATE */
        if (info->status.rates[0].idx >= 0 &&
            !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
                                             IEEE80211_TX_RC_VHT_MCS))) {
                u16 rate;

                rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
                rate = sband->bitrates[info->status.rates[0].idx].bitrate;
                *pos = DIV_ROUND_UP(rate, 5 * (1 << shift));
                /* padding for tx flags */
                pos += 2;
        }

        /* IEEE80211_RADIOTAP_TX_FLAGS */
        txflags = 0;
        if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
            !is_multicast_ether_addr(hdr->addr1))
                txflags |= IEEE80211_RADIOTAP_F_TX_FAIL;

        if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
                txflags |= IEEE80211_RADIOTAP_F_TX_CTS;
        if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
                txflags |= IEEE80211_RADIOTAP_F_TX_RTS;

        put_unaligned_le16(txflags, pos);
        pos += 2;

        /* IEEE80211_RADIOTAP_DATA_RETRIES */
        /* for now report the total retry_count */
        *pos = retry_count;
        pos++;

        if (info->status.rates[0].idx < 0)
                return;

        /* IEEE80211_RADIOTAP_MCS
         * IEEE80211_RADIOTAP_VHT */
        if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
                rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
                pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
                         IEEE80211_RADIOTAP_MCS_HAVE_GI |
                         IEEE80211_RADIOTAP_MCS_HAVE_BW;
                if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
                        pos[1] |= IEEE80211_RADIOTAP_MCS_SGI;
                if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
                        pos[1] |= IEEE80211_RADIOTAP_MCS_BW_40;
                if (info->status.rates[0].flags & IEEE80211_TX_RC_GREEN_FIELD)
                        pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
                pos[2] = info->status.rates[0].idx;
                pos += 3;
        } else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS) {
                u16 known = local->hw.radiotap_vht_details &
                        (IEEE80211_RADIOTAP_VHT_KNOWN_GI |
                         IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH);

                rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);

                /* required alignment from rthdr */
                pos = (u8 *)rthdr + ALIGN(pos - (u8 *)rthdr, 2);

                /* u16 known - IEEE80211_RADIOTAP_VHT_KNOWN_* */
                put_unaligned_le16(known, pos);
                pos += 2;

                /* u8 flags - IEEE80211_RADIOTAP_VHT_FLAG_* */
                if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
                        *pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
                pos++;

                /* u8 bandwidth */
                if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
                        *pos = 1;
                else if (info->status.rates[0].flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
                        *pos = 4;
                else if (info->status.rates[0].flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
                        *pos = 11;
                else /* IEEE80211_TX_RC_{20_MHZ_WIDTH,FIXME:DUP_DATA} */
                        *pos = 0;
                pos++;

                /* u8 mcs_nss[4] */
                *pos = (ieee80211_rate_get_vht_mcs(&info->status.rates[0]) << 4) |
                        ieee80211_rate_get_vht_nss(&info->status.rates[0]);
                pos += 4;

                /* u8 coding */
                pos++;
                /* u8 group_id */
                pos++;
                /* u16 partial_aid */
                pos += 2;
        }
}

/*
 * Handles the tx for TDLS teardown frames.
 * If the frame wasn't ACKed by the peer - it will be re-sent through the AP
 */
static void ieee80211_tdls_td_tx_handle(struct ieee80211_local *local,
                                        struct ieee80211_sub_if_data *sdata,
                                        struct sk_buff *skb, u32 flags)
{
        struct sk_buff *teardown_skb;
        struct sk_buff *orig_teardown_skb;
        bool is_teardown = false;

        /* Get the teardown data we need and free the lock */
        spin_lock(&sdata->u.mgd.teardown_lock);
        teardown_skb = sdata->u.mgd.teardown_skb;
        orig_teardown_skb = sdata->u.mgd.orig_teardown_skb;
        if ((skb == orig_teardown_skb) && teardown_skb) {
                sdata->u.mgd.teardown_skb = NULL;
                sdata->u.mgd.orig_teardown_skb = NULL;
                is_teardown = true;
        }
        spin_unlock(&sdata->u.mgd.teardown_lock);

        if (is_teardown) {
                /* This mechanism relies on being able to get ACKs */
                WARN_ON(!ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS));

                /* Check if peer has ACKed */
                if (flags & IEEE80211_TX_STAT_ACK) {
                        dev_kfree_skb_any(teardown_skb);
                } else {
                        tdls_dbg(sdata,
                                 "TDLS Resending teardown through AP\n");

                        ieee80211_subif_start_xmit(teardown_skb, skb->dev);
                }
        }
}

static struct ieee80211_sub_if_data *
ieee80211_sdata_from_skb(struct ieee80211_local *local, struct sk_buff *skb)
{
        struct ieee80211_sub_if_data *sdata;

        if (skb->dev) {
                list_for_each_entry_rcu(sdata, &local->interfaces, list) {
                        if (!sdata->dev)
                                continue;

                        if (skb->dev == sdata->dev)
                                return sdata;
                }

                return NULL;
        }

        return rcu_dereference(local->p2p_sdata);
}

static void ieee80211_report_ack_skb(struct ieee80211_local *local,
                                     struct ieee80211_tx_info *info,
                                     bool acked, bool dropped)
{
        struct sk_buff *skb;
        unsigned long flags;

        spin_lock_irqsave(&local->ack_status_lock, flags);
        skb = idr_remove(&local->ack_status_frames, info->ack_frame_id);
        spin_unlock_irqrestore(&local->ack_status_lock, flags);

        if (!skb)
                return;

        if (dropped) {
                dev_kfree_skb_any(skb);
                return;
        }

        if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
                u64 cookie = IEEE80211_SKB_CB(skb)->ack.cookie;
                struct ieee80211_sub_if_data *sdata;
                struct ieee80211_hdr *hdr = (void *)skb->data;

                rcu_read_lock();
                sdata = ieee80211_sdata_from_skb(local, skb);
                if (sdata) {
                        if (ieee80211_is_nullfunc(hdr->frame_control) ||
                            ieee80211_is_qos_nullfunc(hdr->frame_control))
                                cfg80211_probe_status(sdata->dev, hdr->addr1,
                                                      cookie, acked,
                                                      GFP_ATOMIC);
                        else
                                cfg80211_mgmt_tx_status(&sdata->wdev, cookie,
                                                        skb->data, skb->len,
                                                        acked, GFP_ATOMIC);
                }
                rcu_read_unlock();

                dev_kfree_skb_any(skb);
        } else {
                /* consumes skb */
                skb_complete_wifi_ack(skb, acked);
        }
}

static void ieee80211_report_used_skb(struct ieee80211_local *local,
                                      struct sk_buff *skb, bool dropped)
{
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (void *)skb->data;
        bool acked = info->flags & IEEE80211_TX_STAT_ACK;

        if (dropped)
                acked = false;

        if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
                struct ieee80211_sub_if_data *sdata;

                rcu_read_lock();

                sdata = ieee80211_sdata_from_skb(local, skb);

                if (!sdata) {
                        skb->dev = NULL;
                } else {
                        unsigned int hdr_size =
                                ieee80211_hdrlen(hdr->frame_control);

                        /* Check to see if packet is a TDLS teardown packet */
                        if (ieee80211_is_data(hdr->frame_control) &&
                            (ieee80211_get_tdls_action(skb, hdr_size) ==
                             WLAN_TDLS_TEARDOWN))
                                ieee80211_tdls_td_tx_handle(local, sdata, skb,
                                                            info->flags);
                        else
                                ieee80211_mgd_conn_tx_status(sdata,
                                                             hdr->frame_control,
                                                             acked);
                }

                rcu_read_unlock();
        } else if (info->ack_frame_id) {
                ieee80211_report_ack_skb(local, info, acked, dropped);
        }

        if (!dropped && skb->destructor) {
                skb->wifi_acked_valid = 1;
                skb->wifi_acked = acked;
        }
}

/*
 * Use a static threshold for now, best value to be determined
 * by testing ...
 * Should it depend on:
 *  - on # of retransmissions
 *  - current throughput (higher value for higher tpt)?
 */
#define STA_LOST_PKT_THRESHOLD  50
#define STA_LOST_TDLS_PKT_THRESHOLD     10
#define STA_LOST_TDLS_PKT_TIME          (10*HZ) /* 10secs since last ACK */

static void ieee80211_lost_packet(struct sta_info *sta,
                                  struct ieee80211_tx_info *info)
{
        /* If driver relies on its own algorithm for station kickout, skip
         * mac80211 packet loss mechanism.
         */
        if (ieee80211_hw_check(&sta->local->hw, REPORTS_LOW_ACK))
                return;

        /* This packet was aggregated but doesn't carry status info */
        if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
            !(info->flags & IEEE80211_TX_STAT_AMPDU))
                return;

        sta->status_stats.lost_packets++;
        if (!sta->sta.tdls &&
            sta->status_stats.lost_packets < STA_LOST_PKT_THRESHOLD)
                return;

        /*
         * If we're in TDLS mode, make sure that all STA_LOST_TDLS_PKT_THRESHOLD
         * of the last packets were lost, and that no ACK was received in the
         * last STA_LOST_TDLS_PKT_TIME ms, before triggering the CQM packet-loss
         * mechanism.
         */
        if (sta->sta.tdls &&
            (sta->status_stats.lost_packets < STA_LOST_TDLS_PKT_THRESHOLD ||
             time_before(jiffies,
                         sta->status_stats.last_tdls_pkt_time +
                         STA_LOST_TDLS_PKT_TIME)))
                return;

        cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
                                    sta->status_stats.lost_packets, GFP_ATOMIC);
        sta->status_stats.lost_packets = 0;
}

static int ieee80211_tx_get_rates(struct ieee80211_hw *hw,
                                  struct ieee80211_tx_info *info,
                                  int *retry_count)
{
        int rates_idx = -1;
        int count = -1;
        int i;

        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
                if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
                    !(info->flags & IEEE80211_TX_STAT_AMPDU)) {
                        /* just the first aggr frame carry status info */
                        info->status.rates[i].idx = -1;
                        info->status.rates[i].count = 0;
                        break;
                } else if (info->status.rates[i].idx < 0) {
                        break;
                } else if (i >= hw->max_report_rates) {
                        /* the HW cannot have attempted that rate */
                        info->status.rates[i].idx = -1;
                        info->status.rates[i].count = 0;
                        break;
                }

                count += info->status.rates[i].count;
        }
        rates_idx = i - 1;

        if (count < 0)
                count = 0;

        *retry_count = count;
        return rates_idx;
}

void ieee80211_tx_monitor(struct ieee80211_local *local, struct sk_buff *skb,
                          struct ieee80211_supported_band *sband,
                          int retry_count, int shift, bool send_to_cooked)
{
        struct sk_buff *skb2;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_sub_if_data *sdata;
        struct net_device *prev_dev = NULL;
        int rtap_len;

        /* send frame to monitor interfaces now */
        rtap_len = ieee80211_tx_radiotap_len(info);
        if (WARN_ON_ONCE(skb_headroom(skb) < rtap_len)) {
                pr_err("ieee80211_tx_status: headroom too small\n");
                dev_kfree_skb(skb);
                return;
        }
        ieee80211_add_tx_radiotap_header(local, sband, skb, retry_count,
                                         rtap_len, shift);

        /* XXX: is this sufficient for BPF? */
        skb_reset_mac_header(skb);
        skb->ip_summed = CHECKSUM_UNNECESSARY;
        skb->pkt_type = PACKET_OTHERHOST;
        skb->protocol = htons(ETH_P_802_2);
        memset(skb->cb, 0, sizeof(skb->cb));

        rcu_read_lock();
        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
                if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
                        if (!ieee80211_sdata_running(sdata))
                                continue;

                        if ((sdata->u.mntr.flags & MONITOR_FLAG_COOK_FRAMES) &&
                            !send_to_cooked)
                                continue;

                        if (prev_dev) {
                                skb2 = skb_clone(skb, GFP_ATOMIC);
                                if (skb2) {
                                        skb2->dev = prev_dev;
                                        netif_rx(skb2);
                                }
                        }

                        prev_dev = sdata->dev;
                }
        }
        if (prev_dev) {
                skb->dev = prev_dev;
                netif_rx(skb);
                skb = NULL;
        }
        rcu_read_unlock();
        dev_kfree_skb(skb);
}

static void __ieee80211_tx_status(struct ieee80211_hw *hw,
                                  struct ieee80211_tx_status *status)
{
        struct sk_buff *skb = status->skb;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = status->info;
        struct sta_info *sta;
        __le16 fc;
        struct ieee80211_supported_band *sband;
        int retry_count;
        int rates_idx;
        bool send_to_cooked;
        bool acked;
        struct ieee80211_bar *bar;
        int shift = 0;
        int tid = IEEE80211_NUM_TIDS;

        rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);

        sband = local->hw.wiphy->bands[info->band];
        fc = hdr->frame_control;

        if (status->sta) {
                sta = container_of(status->sta, struct sta_info, sta);
                shift = ieee80211_vif_get_shift(&sta->sdata->vif);

                if (info->flags & IEEE80211_TX_STATUS_EOSP)
                        clear_sta_flag(sta, WLAN_STA_SP);

                acked = !!(info->flags & IEEE80211_TX_STAT_ACK);

                /* mesh Peer Service Period support */
                if (ieee80211_vif_is_mesh(&sta->sdata->vif) &&
                    ieee80211_is_data_qos(fc))
                        ieee80211_mpsp_trigger_process(
                                ieee80211_get_qos_ctl(hdr), sta, true, acked);

                if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
                        /*
                         * The STA is in power save mode, so assume
                         * that this TX packet failed because of that.
                         */
                        ieee80211_handle_filtered_frame(local, sta, skb);
                        return;
                }

                if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL) &&
                    (ieee80211_is_data(hdr->frame_control)) &&
                    (rates_idx != -1))
                        sta->tx_stats.last_rate =
                                info->status.rates[rates_idx];

                if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
                    (ieee80211_is_data_qos(fc))) {
                        u16 ssn;
                        u8 *qc;

                        qc = ieee80211_get_qos_ctl(hdr);
                        tid = qc[0] & 0xf;
                        ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
                                                & IEEE80211_SCTL_SEQ);
                        ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
                                           tid, ssn);
                } else if (ieee80211_is_data_qos(fc)) {
                        u8 *qc = ieee80211_get_qos_ctl(hdr);

                        tid = qc[0] & 0xf;
                }

                if (!acked && ieee80211_is_back_req(fc)) {
                        u16 control;

                        /*
                         * BAR failed, store the last SSN and retry sending
                         * the BAR when the next unicast transmission on the
                         * same TID succeeds.
                         */
                        bar = (struct ieee80211_bar *) skb->data;
                        control = le16_to_cpu(bar->control);
                        if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
                                u16 ssn = le16_to_cpu(bar->start_seq_num);

                                tid = (control &
                                       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
                                      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;

                                ieee80211_set_bar_pending(sta, tid, ssn);
                        }
                }

                if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
                        ieee80211_handle_filtered_frame(local, sta, skb);
                        return;
                } else {
                        if (!acked)
                                sta->status_stats.retry_failed++;
                        sta->status_stats.retry_count += retry_count;

                        if (ieee80211_is_data_present(fc)) {
                                if (!acked)
                                        sta->status_stats.msdu_failed[tid]++;

                                sta->status_stats.msdu_retries[tid] +=
                                        retry_count;
                        }
                }

                rate_control_tx_status(local, sband, status);
                if (ieee80211_vif_is_mesh(&sta->sdata->vif))
                        ieee80211s_update_metric(local, sta, skb);

                if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
                        ieee80211_frame_acked(sta, skb);

                if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
                    ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
                        ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data,
                                                acked, info->status.tx_time);

                if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
                        if (info->flags & IEEE80211_TX_STAT_ACK) {
                                if (sta->status_stats.lost_packets)
                                        sta->status_stats.lost_packets = 0;

                                /* Track when last TDLS packet was ACKed */
                                if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
                                        sta->status_stats.last_tdls_pkt_time =
                                                jiffies;
                        } else {
                                ieee80211_lost_packet(sta, info);
                        }
                }
        }

        ieee80211_led_tx(local);

        /* SNMP counters
         * Fragments are passed to low-level drivers as separate skbs, so these
         * are actually fragments, not frames. Update frame counters only for
         * the first fragment of the frame. */
        if ((info->flags & IEEE80211_TX_STAT_ACK) ||
            (info->flags & IEEE80211_TX_STAT_NOACK_TRANSMITTED)) {
                if (ieee80211_is_first_frag(hdr->seq_ctrl)) {
                        I802_DEBUG_INC(local->dot11TransmittedFrameCount);
                        if (is_multicast_ether_addr(ieee80211_get_DA(hdr)))
                                I802_DEBUG_INC(local->dot11MulticastTransmittedFrameCount);
                        if (retry_count > 0)
                                I802_DEBUG_INC(local->dot11RetryCount);
                        if (retry_count > 1)
                                I802_DEBUG_INC(local->dot11MultipleRetryCount);
                }

                /* This counter shall be incremented for an acknowledged MPDU
                 * with an individual address in the address 1 field or an MPDU
                 * with a multicast address in the address 1 field of type Data
                 * or Management. */
                if (!is_multicast_ether_addr(hdr->addr1) ||
                    ieee80211_is_data(fc) ||
                    ieee80211_is_mgmt(fc))
                        I802_DEBUG_INC(local->dot11TransmittedFragmentCount);
        } else {
                if (ieee80211_is_first_frag(hdr->seq_ctrl))
                        I802_DEBUG_INC(local->dot11FailedCount);
        }

        if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
            ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS) &&
            !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
            local->ps_sdata && !(local->scanning)) {
                if (info->flags & IEEE80211_TX_STAT_ACK) {
                        local->ps_sdata->u.mgd.flags |=
                                        IEEE80211_STA_NULLFUNC_ACKED;
                } else
                        mod_timer(&local->dynamic_ps_timer, jiffies +
                                        msecs_to_jiffies(10));
        }

        ieee80211_report_used_skb(local, skb, false);

        /* this was a transmitted frame, but now we want to reuse it */
        skb_orphan(skb);

        /* Need to make a copy before skb->cb gets cleared */
        send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
                         !(ieee80211_is_data(fc));

        /*
         * This is a bit racy but we can avoid a lot of work
         * with this test...
         */
        if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
                dev_kfree_skb(skb);
                return;
        }

        /* send to monitor interfaces */
        ieee80211_tx_monitor(local, skb, sband, retry_count, shift, send_to_cooked);
}

void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_status status = {
                .skb = skb,
                .info = IEEE80211_SKB_CB(skb),
        };
        struct rhlist_head *tmp;
        struct sta_info *sta;

        rcu_read_lock();

        for_each_sta_info(local, hdr->addr1, sta, tmp) {
                /* skip wrong virtual interface */
                if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
                        continue;

                status.sta = &sta->sta;
                break;
        }

        __ieee80211_tx_status(hw, &status);
        rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_tx_status);

void ieee80211_tx_status_ext(struct ieee80211_hw *hw,
                             struct ieee80211_tx_status *status)
{
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = status->info;
        struct ieee80211_sta *pubsta = status->sta;
        struct ieee80211_supported_band *sband;
        int retry_count;
        bool acked, noack_success;

        if (status->skb)
                return __ieee80211_tx_status(hw, status);

        if (!status->sta)
                return;

        ieee80211_tx_get_rates(hw, info, &retry_count);

        sband = hw->wiphy->bands[info->band];

        acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
        noack_success = !!(info->flags & IEEE80211_TX_STAT_NOACK_TRANSMITTED);

        if (pubsta) {
                struct sta_info *sta;

                sta = container_of(pubsta, struct sta_info, sta);

                if (!acked)
                        sta->status_stats.retry_failed++;
                sta->status_stats.retry_count += retry_count;

                if (acked) {
                        sta->status_stats.last_ack = jiffies;

                        if (sta->status_stats.lost_packets)
                                sta->status_stats.lost_packets = 0;

                        /* Track when last TDLS packet was ACKed */
                        if (test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH))
                                sta->status_stats.last_tdls_pkt_time = jiffies;
                } else {
                        ieee80211_lost_packet(sta, info);
                }

                rate_control_tx_status(local, sband, status);
        }

        if (acked || noack_success) {
                I802_DEBUG_INC(local->dot11TransmittedFrameCount);
                if (!pubsta)
                        I802_DEBUG_INC(local->dot11MulticastTransmittedFrameCount);
                if (retry_count > 0)
                        I802_DEBUG_INC(local->dot11RetryCount);
                if (retry_count > 1)
                        I802_DEBUG_INC(local->dot11MultipleRetryCount);
        } else {
                I802_DEBUG_INC(local->dot11FailedCount);
        }
}
EXPORT_SYMBOL(ieee80211_tx_status_ext);

void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
{
        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
        cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
                                    num_packets, GFP_ATOMIC);
}
EXPORT_SYMBOL(ieee80211_report_low_ack);

void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
{
        struct ieee80211_local *local = hw_to_local(hw);

        ieee80211_report_used_skb(local, skb, true);
        dev_kfree_skb_any(skb);
}
EXPORT_SYMBOL(ieee80211_free_txskb);

void ieee80211_purge_tx_queue(struct ieee80211_hw *hw,
                              struct sk_buff_head *skbs)
{
        struct sk_buff *skb;

        while ((skb = __skb_dequeue(skbs)))
                ieee80211_free_txskb(hw, skb);
}