/*
 * HT handling
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2007-2010, Intel Corporation
 *
 * 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/ieee80211.h>
#include <linux/export.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "rate.h"

static void __check_htcap_disable(struct ieee80211_ht_cap *ht_capa,
                                  struct ieee80211_ht_cap *ht_capa_mask,
                                  struct ieee80211_sta_ht_cap *ht_cap,
                                  u16 flag)
{
        __le16 le_flag = cpu_to_le16(flag);
        if (ht_capa_mask->cap_info & le_flag) {
                if (!(ht_capa->cap_info & le_flag))
                        ht_cap->cap &= ~flag;
        }
}

static void __check_htcap_enable(struct ieee80211_ht_cap *ht_capa,
                                  struct ieee80211_ht_cap *ht_capa_mask,
                                  struct ieee80211_sta_ht_cap *ht_cap,
                                  u16 flag)
{
        __le16 le_flag = cpu_to_le16(flag);

        if ((ht_capa_mask->cap_info & le_flag) &&
            (ht_capa->cap_info & le_flag))
                ht_cap->cap |= flag;
}

void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
                                     struct ieee80211_sta_ht_cap *ht_cap)
{
        struct ieee80211_ht_cap *ht_capa, *ht_capa_mask;
        u8 *scaps, *smask;
        int i;

        if (!ht_cap->ht_supported)
                return;

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_STATION:
                ht_capa = &sdata->u.mgd.ht_capa;
                ht_capa_mask = &sdata->u.mgd.ht_capa_mask;
                break;
        case NL80211_IFTYPE_ADHOC:
                ht_capa = &sdata->u.ibss.ht_capa;
                ht_capa_mask = &sdata->u.ibss.ht_capa_mask;
                break;
        default:
                WARN_ON_ONCE(1);
                return;
        }

        scaps = (u8 *)(&ht_capa->mcs.rx_mask);
        smask = (u8 *)(&ht_capa_mask->mcs.rx_mask);

        /* NOTE:  If you add more over-rides here, update register_hw
         * ht_capa_mod_mask logic in main.c as well.
         * And, if this method can ever change ht_cap.ht_supported, fix
         * the check in ieee80211_add_ht_ie.
         */

        /* check for HT over-rides, MCS rates first. */
        for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
                u8 m = smask[i];
                ht_cap->mcs.rx_mask[i] &= ~m; /* turn off all masked bits */
                /* Add back rates that are supported */
                ht_cap->mcs.rx_mask[i] |= (m & scaps[i]);
        }

        /* Force removal of HT-40 capabilities? */
        __check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
                              IEEE80211_HT_CAP_SUP_WIDTH_20_40);
        __check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
                              IEEE80211_HT_CAP_SGI_40);

        /* Allow user to disable SGI-20 (SGI-40 is handled above) */
        __check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
                              IEEE80211_HT_CAP_SGI_20);

        /* Allow user to disable the max-AMSDU bit. */
        __check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
                              IEEE80211_HT_CAP_MAX_AMSDU);

        /* Allow user to disable LDPC */
        __check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
                              IEEE80211_HT_CAP_LDPC_CODING);

        /* Allow user to enable 40 MHz intolerant bit. */
        __check_htcap_enable(ht_capa, ht_capa_mask, ht_cap,
                             IEEE80211_HT_CAP_40MHZ_INTOLERANT);

        /* Allow user to decrease AMPDU factor */
        if (ht_capa_mask->ampdu_params_info &
            IEEE80211_HT_AMPDU_PARM_FACTOR) {
                u8 n = ht_capa->ampdu_params_info &
                       IEEE80211_HT_AMPDU_PARM_FACTOR;
                if (n < ht_cap->ampdu_factor)
                        ht_cap->ampdu_factor = n;
        }

        /* Allow the user to increase AMPDU density. */
        if (ht_capa_mask->ampdu_params_info &
            IEEE80211_HT_AMPDU_PARM_DENSITY) {
                u8 n = (ht_capa->ampdu_params_info &
                        IEEE80211_HT_AMPDU_PARM_DENSITY)
                        >> IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT;
                if (n > ht_cap->ampdu_density)
                        ht_cap->ampdu_density = n;
        }
}


bool ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,
                                       struct ieee80211_supported_band *sband,
                                       const struct ieee80211_ht_cap *ht_cap_ie,
                                       struct sta_info *sta)
{
        struct ieee80211_sta_ht_cap ht_cap, own_cap;
        u8 ampdu_info, tx_mcs_set_cap;
        int i, max_tx_streams;
        bool changed;
        enum ieee80211_sta_rx_bandwidth bw;
        enum ieee80211_smps_mode smps_mode;

        memset(&ht_cap, 0, sizeof(ht_cap));

        if (!ht_cap_ie || !sband->ht_cap.ht_supported)
                goto apply;

        ht_cap.ht_supported = true;

        own_cap = sband->ht_cap;

        /*
         * If user has specified capability over-rides, take care
         * of that if the station we're setting up is the AP or TDLS peer that
         * we advertised a restricted capability set to. Override
         * our own capabilities and then use those below.
         */
        if (sdata->vif.type == NL80211_IFTYPE_STATION ||
            sdata->vif.type == NL80211_IFTYPE_ADHOC)
                ieee80211_apply_htcap_overrides(sdata, &own_cap);

        /*
         * The bits listed in this expression should be
         * the same for the peer and us, if the station
         * advertises more then we can't use those thus
         * we mask them out.
         */
        ht_cap.cap = le16_to_cpu(ht_cap_ie->cap_info) &
                (own_cap.cap | ~(IEEE80211_HT_CAP_LDPC_CODING |
                                 IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
                                 IEEE80211_HT_CAP_GRN_FLD |
                                 IEEE80211_HT_CAP_SGI_20 |
                                 IEEE80211_HT_CAP_SGI_40 |
                                 IEEE80211_HT_CAP_DSSSCCK40));

        /*
         * The STBC bits are asymmetric -- if we don't have
         * TX then mask out the peer's RX and vice versa.
         */
        if (!(own_cap.cap & IEEE80211_HT_CAP_TX_STBC))
                ht_cap.cap &= ~IEEE80211_HT_CAP_RX_STBC;
        if (!(own_cap.cap & IEEE80211_HT_CAP_RX_STBC))
                ht_cap.cap &= ~IEEE80211_HT_CAP_TX_STBC;

        ampdu_info = ht_cap_ie->ampdu_params_info;
        ht_cap.ampdu_factor =
                ampdu_info & IEEE80211_HT_AMPDU_PARM_FACTOR;
        ht_cap.ampdu_density =
                (ampdu_info & IEEE80211_HT_AMPDU_PARM_DENSITY) >> 2;

        /* own MCS TX capabilities */
        tx_mcs_set_cap = own_cap.mcs.tx_params;

        /* Copy peer MCS TX capabilities, the driver might need them. */
        ht_cap.mcs.tx_params = ht_cap_ie->mcs.tx_params;

        /* can we TX with MCS rates? */
        if (!(tx_mcs_set_cap & IEEE80211_HT_MCS_TX_DEFINED))
                goto apply;

        /* Counting from 0, therefore +1 */
        if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_RX_DIFF)
                max_tx_streams =
                        ((tx_mcs_set_cap & IEEE80211_HT_MCS_TX_MAX_STREAMS_MASK)
                                >> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
        else
                max_tx_streams = IEEE80211_HT_MCS_TX_MAX_STREAMS;

        /*
         * 802.11n-2009 20.3.5 / 20.6 says:
         * - indices 0 to 7 and 32 are single spatial stream
         * - 8 to 31 are multiple spatial streams using equal modulation
         *   [8..15 for two streams, 16..23 for three and 24..31 for four]
         * - remainder are multiple spatial streams using unequal modulation
         */
        for (i = 0; i < max_tx_streams; i++)
                ht_cap.mcs.rx_mask[i] =
                        own_cap.mcs.rx_mask[i] & ht_cap_ie->mcs.rx_mask[i];

        if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_UNEQUAL_MODULATION)
                for (i = IEEE80211_HT_MCS_UNEQUAL_MODULATION_START_BYTE;
                     i < IEEE80211_HT_MCS_MASK_LEN; i++)
                        ht_cap.mcs.rx_mask[i] =
                                own_cap.mcs.rx_mask[i] &
                                        ht_cap_ie->mcs.rx_mask[i];

        /* handle MCS rate 32 too */
        if (own_cap.mcs.rx_mask[32/8] & ht_cap_ie->mcs.rx_mask[32/8] & 1)
                ht_cap.mcs.rx_mask[32/8] |= 1;

        /* set Rx highest rate */
        ht_cap.mcs.rx_highest = ht_cap_ie->mcs.rx_highest;

        if (ht_cap.cap & IEEE80211_HT_CAP_MAX_AMSDU)
                sta->sta.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_HT_7935;
        else
                sta->sta.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_HT_3839;

 apply:
        changed = memcmp(&sta->sta.ht_cap, &ht_cap, sizeof(ht_cap));

        memcpy(&sta->sta.ht_cap, &ht_cap, sizeof(ht_cap));

        switch (sdata->vif.bss_conf.chandef.width) {
        default:
                WARN_ON_ONCE(1);
                /* fall through */
        case NL80211_CHAN_WIDTH_20_NOHT:
        case NL80211_CHAN_WIDTH_20:
                bw = IEEE80211_STA_RX_BW_20;
                break;
        case NL80211_CHAN_WIDTH_40:
        case NL80211_CHAN_WIDTH_80:
        case NL80211_CHAN_WIDTH_80P80:
        case NL80211_CHAN_WIDTH_160:
                bw = ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40 ?
                                IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;
                break;
        }

        sta->sta.bandwidth = bw;

        sta->cur_max_bandwidth =
                ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40 ?
                                IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;

        switch ((ht_cap.cap & IEEE80211_HT_CAP_SM_PS)
                        >> IEEE80211_HT_CAP_SM_PS_SHIFT) {
        case WLAN_HT_CAP_SM_PS_INVALID:
        case WLAN_HT_CAP_SM_PS_STATIC:
                smps_mode = IEEE80211_SMPS_STATIC;
                break;
        case WLAN_HT_CAP_SM_PS_DYNAMIC:
                smps_mode = IEEE80211_SMPS_DYNAMIC;
                break;
        case WLAN_HT_CAP_SM_PS_DISABLED:
                smps_mode = IEEE80211_SMPS_OFF;
                break;
        }

        if (smps_mode != sta->sta.smps_mode)
                changed = true;
        sta->sta.smps_mode = smps_mode;

        return changed;
}

void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta,
                                         enum ieee80211_agg_stop_reason reason)
{
        int i;

        cancel_work_sync(&sta->ampdu_mlme.work);

        for (i = 0; i <  IEEE80211_NUM_TIDS; i++) {
                __ieee80211_stop_tx_ba_session(sta, i, reason);
                __ieee80211_stop_rx_ba_session(sta, i, WLAN_BACK_RECIPIENT,
                                               WLAN_REASON_QSTA_LEAVE_QBSS,
                                               reason != AGG_STOP_DESTROY_STA &&
                                               reason != AGG_STOP_PEER_REQUEST);
        }
}

void ieee80211_ba_session_work(struct work_struct *work)
{
        struct sta_info *sta =
                container_of(work, struct sta_info, ampdu_mlme.work);
        struct tid_ampdu_tx *tid_tx;
        int tid;

        /*
         * When this flag is set, new sessions should be
         * blocked, and existing sessions will be torn
         * down by the code that set the flag, so this
         * need not run.
         */
        if (test_sta_flag(sta, WLAN_STA_BLOCK_BA))
                return;

        mutex_lock(&sta->ampdu_mlme.mtx);
        for (tid = 0; tid < IEEE80211_NUM_TIDS; tid++) {
                if (test_and_clear_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired))
                        ___ieee80211_stop_rx_ba_session(
                                sta, tid, WLAN_BACK_RECIPIENT,
                                WLAN_REASON_QSTA_TIMEOUT, true);

                if (test_and_clear_bit(tid,
                                       sta->ampdu_mlme.tid_rx_stop_requested))
                        ___ieee80211_stop_rx_ba_session(
                                sta, tid, WLAN_BACK_RECIPIENT,
                                WLAN_REASON_UNSPECIFIED, true);

                spin_lock_bh(&sta->lock);

                tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
                if (tid_tx) {
                        /*
                         * Assign it over to the normal tid_tx array
                         * where it "goes live".
                         */

                        sta->ampdu_mlme.tid_start_tx[tid] = NULL;
                        /* could there be a race? */
                        if (sta->ampdu_mlme.tid_tx[tid])
                                kfree(tid_tx);
                        else
                                ieee80211_assign_tid_tx(sta, tid, tid_tx);
                        spin_unlock_bh(&sta->lock);

                        ieee80211_tx_ba_session_handle_start(sta, tid);
                        continue;
                }
                spin_unlock_bh(&sta->lock);

                tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
                if (tid_tx && test_and_clear_bit(HT_AGG_STATE_WANT_STOP,
                                                 &tid_tx->state))
                        ___ieee80211_stop_tx_ba_session(sta, tid,
                                                        AGG_STOP_LOCAL_REQUEST);
        }
        mutex_unlock(&sta->ampdu_mlme.mtx);
}

void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
                          const u8 *da, u16 tid,
                          u16 initiator, u16 reason_code)
{
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        struct ieee80211_mgmt *mgmt;
        u16 params;

        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
        if (!skb)
                return;

        skb_reserve(skb, local->hw.extra_tx_headroom);
        mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
        memset(mgmt, 0, 24);
        memcpy(mgmt->da, da, ETH_ALEN);
        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
        if (sdata->vif.type == NL80211_IFTYPE_AP ||
            sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
            sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
                memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
        else if (sdata->vif.type == NL80211_IFTYPE_STATION)
                memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
        else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
                memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);

        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
                                          IEEE80211_STYPE_ACTION);

        skb_put(skb, 1 + sizeof(mgmt->u.action.u.delba));

        mgmt->u.action.category = WLAN_CATEGORY_BACK;
        mgmt->u.action.u.delba.action_code = WLAN_ACTION_DELBA;
        params = (u16)(initiator << 11);        /* bit 11 initiator */
        params |= (u16)(tid << 12);             /* bit 15:12 TID number */

        mgmt->u.action.u.delba.params = cpu_to_le16(params);
        mgmt->u.action.u.delba.reason_code = cpu_to_le16(reason_code);

        ieee80211_tx_skb(sdata, skb);
}

void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
                             struct sta_info *sta,
                             struct ieee80211_mgmt *mgmt, size_t len)
{
        u16 tid, params;
        u16 initiator;

        params = le16_to_cpu(mgmt->u.action.u.delba.params);
        tid = (params & IEEE80211_DELBA_PARAM_TID_MASK) >> 12;
        initiator = (params & IEEE80211_DELBA_PARAM_INITIATOR_MASK) >> 11;

        ht_dbg_ratelimited(sdata, "delba from %pM (%s) tid %d reason code %d\n",
                           mgmt->sa, initiator ? "initiator" : "recipient",
                           tid,
                           le16_to_cpu(mgmt->u.action.u.delba.reason_code));

        if (initiator == WLAN_BACK_INITIATOR)
                __ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_INITIATOR, 0,
                                               true);
        else
                __ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_PEER_REQUEST);
}

int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
                               enum ieee80211_smps_mode smps, const u8 *da,
                               const u8 *bssid)
{
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        struct ieee80211_mgmt *action_frame;

        /* 27 = header + category + action + smps mode */
        skb = dev_alloc_skb(27 + local->hw.extra_tx_headroom);
        if (!skb)
                return -ENOMEM;

        skb_reserve(skb, local->hw.extra_tx_headroom);
        action_frame = (void *)skb_put(skb, 27);
        memcpy(action_frame->da, da, ETH_ALEN);
        memcpy(action_frame->sa, sdata->dev->dev_addr, ETH_ALEN);
        memcpy(action_frame->bssid, bssid, ETH_ALEN);
        action_frame->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
                                                  IEEE80211_STYPE_ACTION);
        action_frame->u.action.category = WLAN_CATEGORY_HT;
        action_frame->u.action.u.ht_smps.action = WLAN_HT_ACTION_SMPS;
        switch (smps) {
        case IEEE80211_SMPS_AUTOMATIC:
        case IEEE80211_SMPS_NUM_MODES:
                WARN_ON(1);
        case IEEE80211_SMPS_OFF:
                action_frame->u.action.u.ht_smps.smps_control =
                                WLAN_HT_SMPS_CONTROL_DISABLED;
                break;
        case IEEE80211_SMPS_STATIC:
                action_frame->u.action.u.ht_smps.smps_control =
                                WLAN_HT_SMPS_CONTROL_STATIC;
                break;
        case IEEE80211_SMPS_DYNAMIC:
                action_frame->u.action.u.ht_smps.smps_control =
                                WLAN_HT_SMPS_CONTROL_DYNAMIC;
                break;
        }

        /* we'll do more on status of this frame */
        IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
        ieee80211_tx_skb(sdata, skb);

        return 0;
}

void ieee80211_request_smps_mgd_work(struct work_struct *work)
{
        struct ieee80211_sub_if_data *sdata =
                container_of(work, struct ieee80211_sub_if_data,
                             u.mgd.request_smps_work);

        sdata_lock(sdata);
        __ieee80211_request_smps_mgd(sdata, sdata->u.mgd.driver_smps_mode);
        sdata_unlock(sdata);
}

void ieee80211_request_smps_ap_work(struct work_struct *work)
{
        struct ieee80211_sub_if_data *sdata =
                container_of(work, struct ieee80211_sub_if_data,
                             u.ap.request_smps_work);

        sdata_lock(sdata);
        if (sdata_dereference(sdata->u.ap.beacon, sdata))
                __ieee80211_request_smps_ap(sdata,
                                            sdata->u.ap.driver_smps_mode);
        sdata_unlock(sdata);
}

void ieee80211_request_smps(struct ieee80211_vif *vif,
                            enum ieee80211_smps_mode smps_mode)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);

        if (WARN_ON_ONCE(vif->type != NL80211_IFTYPE_STATION &&
                         vif->type != NL80211_IFTYPE_AP))
                return;

        if (vif->type == NL80211_IFTYPE_STATION) {
                if (sdata->u.mgd.driver_smps_mode == smps_mode)
                        return;
                sdata->u.mgd.driver_smps_mode = smps_mode;
                ieee80211_queue_work(&sdata->local->hw,
                                     &sdata->u.mgd.request_smps_work);
        } else {
                /* AUTOMATIC is meaningless in AP mode */
                if (WARN_ON_ONCE(smps_mode == IEEE80211_SMPS_AUTOMATIC))
                        return;
                if (sdata->u.ap.driver_smps_mode == smps_mode)
                        return;
                sdata->u.ap.driver_smps_mode = smps_mode;
                ieee80211_queue_work(&sdata->local->hw,
                                     &sdata->u.ap.request_smps_work);
        }
}
/* this might change ... don't want non-open drivers using it */
EXPORT_SYMBOL_GPL(ieee80211_request_smps);