agg-rx.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/slab.h>
#include <linux/export.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"

static void ieee80211_free_tid_rx(struct rcu_head *h)
{
    struct tid_ampdu_rx *tid_rx =
        container_of(h, struct tid_ampdu_rx, rcu_head);
    int i;

    del_timer_sync(&tid_rx->reorder_timer);

    for (i = 0; i < tid_rx->buf_size; i++)
        dev_kfree_skb(tid_rx->reorder_buf[i]);
    kfree(tid_rx->reorder_buf);
    kfree(tid_rx->reorder_time);
    kfree(tid_rx);
}

void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
                     u16 initiator, u16 reason, bool tx)
{
    struct ieee80211_local *local = sta->local;
    struct tid_ampdu_rx *tid_rx;

    lockdep_assert_held(&sta->ampdu_mlme.mtx);

    tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
                    lockdep_is_held(&sta->ampdu_mlme.mtx));

    if (!tid_rx)
        return;

    RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);

    ht_dbg(sta->sdata,
           "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
           sta->sta.addr, tid,
           initiator == WLAN_BACK_RECIPIENT ? "recipient" : "inititator",
           (int)reason);

    if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
                 &sta->sta, tid, NULL, 0))
        sdata_info(sta->sdata,
               "HW problem - can not stop rx aggregation for tid %d\n",
               tid);

    /* check if this is a self generated aggregation halt */
    if (initiator == WLAN_BACK_RECIPIENT && tx)
        ieee80211_send_delba(sta->sdata, sta->sta.addr,
                     tid, WLAN_BACK_RECIPIENT, reason);

    del_timer_sync(&tid_rx->session_timer);

    call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
}

void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
                    u16 initiator, u16 reason, bool tx)
{
    mutex_lock(&sta->ampdu_mlme.mtx);
    ___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason, tx);
    mutex_unlock(&sta->ampdu_mlme.mtx);
}

void ieee80211_stop_rx_ba_session(struct ieee80211_vif *vif, u16 ba_rx_bitmap,
                  const u8 *addr)
{
    struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
    struct sta_info *sta;
    int i;

    rcu_read_lock();
    sta = sta_info_get_bss(sdata, addr);
    if (!sta) {
        rcu_read_unlock();
        return;
    }

    for (i = 0; i < STA_TID_NUM; i++)
        if (ba_rx_bitmap & BIT(i))
            set_bit(i, sta->ampdu_mlme.tid_rx_stop_requested);

    ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
    rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_stop_rx_ba_session);

/*
 * After accepting the AddBA Request we activated a timer,
 * resetting it after each frame that arrives from the originator.
 */
static void sta_rx_agg_session_timer_expired(unsigned long data)
{
    /* not an elegant detour, but there is no choice as the timer passes
     * only one argument, and various sta_info are needed here, so init
     * flow in sta_info_create gives the TID as data, while the timer_to_id
     * array gives the sta through container_of */
    u8 *ptid = (u8 *)data;
    u8 *timer_to_id = ptid - *ptid;
    struct sta_info *sta = container_of(timer_to_id, struct sta_info,
                     timer_to_tid[0]);
    struct tid_ampdu_rx *tid_rx;
    unsigned long timeout;

    rcu_read_lock();
    tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[*ptid]);
    if (!tid_rx) {
        rcu_read_unlock();
        return;
    }

    timeout = tid_rx->last_rx + TU_TO_JIFFIES(tid_rx->timeout);
    if (time_is_after_jiffies(timeout)) {
        mod_timer(&tid_rx->session_timer, timeout);
        rcu_read_unlock();
        return;
    }
    rcu_read_unlock();

    ht_dbg(sta->sdata, "rx session timer expired on tid %d\n", (u16)*ptid);

    set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
    ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
}

static void sta_rx_agg_reorder_timer_expired(unsigned long data)
{
    u8 *ptid = (u8 *)data;
    u8 *timer_to_id = ptid - *ptid;
    struct sta_info *sta = container_of(timer_to_id, struct sta_info,
            timer_to_tid[0]);

    rcu_read_lock();
    ieee80211_release_reorder_timeout(sta, *ptid);
    rcu_read_unlock();
}

static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
                      u8 dialog_token, u16 status, u16 policy,
                      u16 buf_size, u16 timeout)
{
    struct ieee80211_local *local = sdata->local;
    struct sk_buff *skb;
    struct ieee80211_mgmt *mgmt;
    u16 capab;

    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.addba_resp));
    mgmt->u.action.category = WLAN_CATEGORY_BACK;
    mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
    mgmt->u.action.u.addba_resp.dialog_token = dialog_token;

    capab = (u16)(policy << 1); /* bit 1 aggregation policy */
    capab |= (u16)(tid << 2);   /* bit 5:2 TID number */
    capab |= (u16)(buf_size << 6);  /* bit 15:6 max size of aggregation */

    mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
    mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
    mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);

    ieee80211_tx_skb(sdata, skb);
}

void ieee80211_process_addba_request(struct ieee80211_local *local,
                     struct sta_info *sta,
                     struct ieee80211_mgmt *mgmt,
                     size_t len)
{
    struct tid_ampdu_rx *tid_agg_rx;
    u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
    u8 dialog_token;
    int ret = -EOPNOTSUPP;

    /* extract session parameters from addba request frame */
    dialog_token = mgmt->u.action.u.addba_req.dialog_token;
    timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
    start_seq_num =
        le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;

    capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
    ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
    tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
    buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;

    status = WLAN_STATUS_REQUEST_DECLINED;

    if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
        ht_dbg(sta->sdata, "Suspend in progress - Denying ADDBA request\n");
        goto end_no_lock;
    }

    /* sanity check for incoming parameters:
     * check if configuration can support the BA policy
     * and if buffer size does not exceeds max value */
    /* XXX: check own ht delayed BA capability?? */
    if (((ba_policy != 1) &&
         (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
        (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
        status = WLAN_STATUS_INVALID_QOS_PARAM;
        ht_dbg_ratelimited(sta->sdata,
                   "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n",
                   mgmt->sa, tid, ba_policy, buf_size);
        goto end_no_lock;
    }
    /* determine default buffer size */
    if (buf_size == 0)
        buf_size = IEEE80211_MAX_AMPDU_BUF;

    /* make sure the size doesn't exceed the maximum supported by the hw */
    if (buf_size > local->hw.max_rx_aggregation_subframes)
        buf_size = local->hw.max_rx_aggregation_subframes;

    /* examine state machine */
    mutex_lock(&sta->ampdu_mlme.mtx);

    if (sta->ampdu_mlme.tid_rx[tid]) {
        ht_dbg_ratelimited(sta->sdata,
                   "unexpected AddBA Req from %pM on tid %u\n",
                   mgmt->sa, tid);

        /* delete existing Rx BA session on the same tid */
        ___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
                        WLAN_STATUS_UNSPECIFIED_QOS,
                        false);
    }

    /* prepare A-MPDU MLME for Rx aggregation */
    tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
    if (!tid_agg_rx)
        goto end;

    spin_lock_init(&tid_agg_rx->reorder_lock);

    /* rx timer */
    tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
    tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
    init_timer_deferrable(&tid_agg_rx->session_timer);

    /* rx reorder timer */
    tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
    tid_agg_rx->reorder_timer.data = (unsigned long)&sta->timer_to_tid[tid];
    init_timer(&tid_agg_rx->reorder_timer);

    /* prepare reordering buffer */
    tid_agg_rx->reorder_buf =
        kcalloc(buf_size, sizeof(struct sk_buff *), GFP_KERNEL);
    tid_agg_rx->reorder_time =
        kcalloc(buf_size, sizeof(unsigned long), GFP_KERNEL);
    if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
        kfree(tid_agg_rx->reorder_buf);
        kfree(tid_agg_rx->reorder_time);
        kfree(tid_agg_rx);
        goto end;
    }

    ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
                   &sta->sta, tid, &start_seq_num, 0);
    ht_dbg(sta->sdata, "Rx A-MPDU request on tid %d result %d\n", tid, ret);
    if (ret) {
        kfree(tid_agg_rx->reorder_buf);
        kfree(tid_agg_rx->reorder_time);
        kfree(tid_agg_rx);
        goto end;
    }

    /* update data */
    tid_agg_rx->dialog_token = dialog_token;
    tid_agg_rx->ssn = start_seq_num;
    tid_agg_rx->head_seq_num = start_seq_num;
    tid_agg_rx->buf_size = buf_size;
    tid_agg_rx->timeout = timeout;
    tid_agg_rx->stored_mpdu_num = 0;
    status = WLAN_STATUS_SUCCESS;

    /* activate it for RX */
    rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);

    if (timeout) {
        mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
        tid_agg_rx->last_rx = jiffies;
    }

end:
    mutex_unlock(&sta->ampdu_mlme.mtx);

end_no_lock:
    ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
                  dialog_token, status, 1, buf_size, timeout);
}