/*
 * 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>
 *
 * 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 <net/mac80211.h>
#include "ieee80211_i.h"
#include "rate.h"
#include "mesh.h"
#include "led.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))) {
                dev_kfree_skb_irq(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);

        /*
         * 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->tx_filtered_count++;

        /*
         * 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_flags(sta, WLAN_STA_CLEAR_PS_FILT);

        /*
         * 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.
         */
        if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
            skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
                skb_queue_tail(&sta->tx_filtered, skb);
                return;
        }

        if (!test_sta_flags(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;
        }

#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
        if (net_ratelimit())
                wiphy_debug(local->hw.wiphy,
                            "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
                            skb_queue_len(&sta->tx_filtered),
                            !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
#endif
        dev_kfree_skb(skb);
}

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_is_action(mgmt->frame_control) &&
            sdata->vif.type == NL80211_IFTYPE_STATION &&
            mgmt->u.action.category == WLAN_CATEGORY_HT &&
            mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
                /*
                 * 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 is before we're associated.
                 */
                switch (mgmt->u.action.u.ht_smps.smps_control) {
                case WLAN_HT_SMPS_CONTROL_DYNAMIC:
                        sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
                        break;
                case WLAN_HT_SMPS_CONTROL_STATIC:
                        sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
                        break;
                case WLAN_HT_SMPS_CONTROL_DISABLED:
                default: /* shouldn't happen since we don't send that */
                        sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
                        break;
                }

                ieee80211_queue_work(&local->hw, &local->recalc_smps);
        }
}

/*
 * 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

void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
{
        struct sk_buff *skb2;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
        struct ieee80211_local *local = hw_to_local(hw);
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        u16 frag, type;
        __le16 fc;
        struct ieee80211_supported_band *sband;
        struct ieee80211_tx_status_rtap_hdr *rthdr;
        struct ieee80211_sub_if_data *sdata;
        struct net_device *prev_dev = NULL;
        struct sta_info *sta, *tmp;
        int retry_count = -1, i;
        int rates_idx = -1;
        bool send_to_cooked;
        bool acked;

        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
                /* the HW cannot have attempted that rate */
                if (i >= hw->max_report_rates) {
                        info->status.rates[i].idx = -1;
                        info->status.rates[i].count = 0;
                } else if (info->status.rates[i].idx >= 0) {
                        rates_idx = i;
                }

                retry_count += info->status.rates[i].count;
        }
        if (retry_count < 0)
                retry_count = 0;

        rcu_read_lock();

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

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

                acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
                if (!acked && test_sta_flags(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);
                        rcu_read_unlock();
                        return;
                }

                if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
                    (rates_idx != -1))
                        sta->last_tx_rate = info->status.rates[rates_idx];

                if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
                    (ieee80211_is_data_qos(fc))) {
                        u16 tid, 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, hdr->addr1,
                                           tid, ssn);
                }

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

                rate_control_tx_status(local, sband, sta, skb);
                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) &&
                    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
                        ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);

                if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
                        if (info->flags & IEEE80211_TX_STAT_ACK) {
                                if (sta->lost_packets)
                                        sta->lost_packets = 0;
                        } else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
                                cfg80211_cqm_pktloss_notify(sta->sdata->dev,
                                                            sta->sta.addr,
                                                            sta->lost_packets,
                                                            GFP_ATOMIC);
                                sta->lost_packets = 0;
                        }
                }
        }

        rcu_read_unlock();

        ieee80211_led_tx(local, 0);

        /* 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. */

        frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
        type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;

        if (info->flags & IEEE80211_TX_STAT_ACK) {
                if (frag == 0) {
                        local->dot11TransmittedFrameCount++;
                        if (is_multicast_ether_addr(hdr->addr1))
                                local->dot11MulticastTransmittedFrameCount++;
                        if (retry_count > 0)
                                local->dot11RetryCount++;
                        if (retry_count > 1)
                                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) ||
                    type == IEEE80211_FTYPE_DATA ||
                    type == IEEE80211_FTYPE_MGMT)
                        local->dot11TransmittedFragmentCount++;
        } else {
                if (frag == 0)
                        local->dot11FailedCount++;
        }

        if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
            (local->hw.flags & IEEE80211_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;
                        ieee80211_queue_work(&local->hw,
                                        &local->dynamic_ps_enable_work);
                } else
                        mod_timer(&local->dynamic_ps_timer, jiffies +
                                        msecs_to_jiffies(10));
        }

        if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
                struct ieee80211_work *wk;
                u64 cookie = (unsigned long)skb;

                rcu_read_lock();
                list_for_each_entry_rcu(wk, &local->work_list, list) {
                        if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
                                continue;
                        if (wk->offchan_tx.frame != skb)
                                continue;
                        wk->offchan_tx.frame = NULL;
                        break;
                }
                rcu_read_unlock();
                if (local->hw_roc_skb_for_status == skb) {
                        cookie = local->hw_roc_cookie ^ 2;
                        local->hw_roc_skb_for_status = NULL;
                }
                cfg80211_mgmt_tx_status(
                        skb->dev, cookie, skb->data, skb->len,
                        !!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
        }

        /* 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) ||
                        (type != IEEE80211_FTYPE_DATA);

        /*
         * 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 frame to monitor interfaces now */

        if (skb_headroom(skb) < sizeof(*rthdr)) {
                printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
                dev_kfree_skb(skb);
                return;
        }

        rthdr = (struct ieee80211_tx_status_rtap_hdr *)
                                skb_push(skb, sizeof(*rthdr));

        memset(rthdr, 0, sizeof(*rthdr));
        rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
        rthdr->hdr.it_present =
                cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
                            (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
                            (1 << IEEE80211_RADIOTAP_RATE));

        if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
            !is_multicast_ether_addr(hdr->addr1))
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);

        /*
         * XXX: Once radiotap gets the bitmap reset thing the vendor
         *      extensions proposal contains, we can actually report
         *      the whole set of tries we did.
         */
        if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
            (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
        else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
                rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
        if (info->status.rates[0].idx >= 0 &&
            !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
                rthdr->rate = sband->bitrates[
                                info->status.rates[0].idx].bitrate / 5;

        /* for now report the total retry_count */
        rthdr->data_retries = retry_count;

        /* XXX: is this sufficient for BPF? */
        skb_set_mac_header(skb, 0);
        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);
}
EXPORT_SYMBOL(ieee80211_tx_status);