ht.c

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/*
 * HT handling
 *
 * Copyright 2003, Jouni Malinen <[email protected]>
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007  Jiri Benc <[email protected]>
 * Copyright 2007, Michael Wu <[email protected]>
 * 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_sub_if_data *sdata,
                  struct ieee80211_sta_ht_cap *ht_cap,
                  u16 flag)
{
    __le16 le_flag = cpu_to_le16(flag);
    if (sdata->u.mgd.ht_capa_mask.cap_info & le_flag) {
        if (!(sdata->u.mgd.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)
{
    u8 *scaps = (u8 *)(&sdata->u.mgd.ht_capa.mcs.rx_mask);
    u8 *smask = (u8 *)(&sdata->u.mgd.ht_capa_mask.mcs.rx_mask);
    int i;

    if (sdata->vif.type != NL80211_IFTYPE_STATION) {
        /* AP interfaces call this code when adding new stations,
         * so just silently ignore non station interfaces.
         */
        return;
    }

    /* NOTE:  If you add more over-rides here, update register_hw
     * ht_capa_mod_msk 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(sdata, ht_cap, IEEE80211_HT_CAP_SUP_WIDTH_20_40);
    __check_htcap_disable(sdata, ht_cap, IEEE80211_HT_CAP_SGI_40);

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

    /* Allow user to decrease AMPDU factor */
    if (sdata->u.mgd.ht_capa_mask.ampdu_params_info &
        IEEE80211_HT_AMPDU_PARM_FACTOR) {
        u8 n = sdata->u.mgd.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 (sdata->u.mgd.ht_capa_mask.ampdu_params_info &
        IEEE80211_HT_AMPDU_PARM_DENSITY) {
        u8 n = (sdata->u.mgd.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;
    }
}


void ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,
                       struct ieee80211_supported_band *sband,
                       struct ieee80211_ht_cap *ht_cap_ie,
                       struct ieee80211_sta_ht_cap *ht_cap)
{
    u8 ampdu_info, tx_mcs_set_cap;
    int i, max_tx_streams;

    BUG_ON(!ht_cap);

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

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

    ht_cap->ht_supported = true;

    /*
     * 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) &
        (sband->ht_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 (!(sband->ht_cap.cap & IEEE80211_HT_CAP_TX_STBC))
        ht_cap->cap &= ~IEEE80211_HT_CAP_RX_STBC;
    if (!(sband->ht_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 = sband->ht_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))
        return;

    /* 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] =
            sband->ht_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] =
                sband->ht_cap.mcs.rx_mask[i] &
                    ht_cap_ie->mcs.rx_mask[i];

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

    /*
     * If user has specified capability over-rides, take care
     * of that here.
     */
    ieee80211_apply_htcap_overrides(sdata, ht_cap);
}

void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta, bool tx)
{
    int i;

    cancel_work_sync(&sta->ampdu_mlme.work);

    for (i = 0; i <  STA_TID_NUM; i++) {
        __ieee80211_stop_tx_ba_session(sta, i, WLAN_BACK_INITIATOR, tx);
        __ieee80211_stop_rx_ba_session(sta, i, WLAN_BACK_RECIPIENT,
                           WLAN_REASON_QSTA_LEAVE_QBSS, tx);
    }
}

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 < STA_TID_NUM; 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);

        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".
             */
            spin_lock_bh(&sta->lock);

            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;
        }

        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,
                            WLAN_BACK_INITIATOR,
                            true);
    }
    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_tid(sdata, skb, tid);
}

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, WLAN_BACK_RECIPIENT,
                           true);
}

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

    mutex_lock(&sdata->u.mgd.mtx);
    __ieee80211_request_smps(sdata, sdata->u.mgd.driver_smps_mode);
    mutex_unlock(&sdata->u.mgd.mtx);
}

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(vif->type != NL80211_IFTYPE_STATION))
        return;

    if (WARN_ON(smps_mode == IEEE80211_SMPS_OFF))
        smps_mode = IEEE80211_SMPS_AUTOMATIC;

    sdata->u.mgd.driver_smps_mode = smps_mode;

    ieee80211_queue_work(&sdata->local->hw,
                 &sdata->u.mgd.request_smps_work);
}
/* this might change ... don't want non-open drivers using it */
EXPORT_SYMBOL_GPL(ieee80211_request_smps);