// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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
 * Copyright(c) 2015-2017 Intel Deutschland GmbH
 * Copyright (C) 2018-2026 Intel Corporation
 */

/**
 * DOC: RX A-MPDU aggregation
 *
 * Aggregation on the RX side requires only implementing the
 * @ampdu_action callback that is invoked to start/stop any
 * block-ack sessions for RX aggregation.
 *
 * When RX aggregation is started by the peer, the driver is
 * notified via @ampdu_action function, with the
 * %IEEE80211_AMPDU_RX_START action, and may reject the request
 * in which case a negative response is sent to the peer, if it
 * accepts it a positive response is sent.
 *
 * While the session is active, the device/driver are required
 * to de-aggregate frames and pass them up one by one to mac80211,
 * which will handle the reorder buffer.
 *
 * When the aggregation session is stopped again by the peer or
 * ourselves, the driver's @ampdu_action function will be called
 * with the action %IEEE80211_AMPDU_RX_STOP. In this case, the
 * call must not fail.
 */

#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;

        for (i = 0; i < tid_rx->buf_size; i++)
                __skb_queue_purge(&tid_rx->reorder[i].buf);
        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;
        struct ieee80211_ampdu_params params = {
                .sta = &sta->sta,
                .action = IEEE80211_AMPDU_RX_STOP,
                .tid = tid,
                .amsdu = false,
                .timeout = 0,
                .ssn = 0,
        };

        lockdep_assert_wiphy(sta->local->hw.wiphy);

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

        if (!test_bit(tid, sta->ampdu_mlme.agg_session_valid))
                return;

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

        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" : "initiator",
               (int)reason);

        if (drv_ampdu_action(local, sta->sdata, &params))
                sdata_info(sta->sdata,
                           "HW problem - can not stop rx aggregation for %pM tid %d\n",
                           sta->sta.addr, 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,
                                     ieee80211_s1g_use_ndp_ba(sta->sdata, sta));

        /*
         * return here in case tid_rx is not assigned - which will happen if
         * IEEE80211_HW_SUPPORTS_REORDERING_BUFFER is set.
         */
        if (!tid_rx)
                return;

        timer_delete_sync(&tid_rx->session_timer);

        /* make sure ieee80211_sta_reorder_release() doesn't re-arm the timer */
        spin_lock_bh(&tid_rx->reorder_lock);
        tid_rx->removed = true;
        spin_unlock_bh(&tid_rx->reorder_lock);
        timer_delete_sync(&tid_rx->reorder_timer);

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

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 < IEEE80211_NUM_TIDS; i++)
                if (ba_rx_bitmap & BIT(i))
                        set_bit(i, sta->ampdu_mlme.tid_rx_stop_requested);

        wiphy_work_queue(sta->local->hw.wiphy, &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(struct timer_list *t)
{
        struct tid_ampdu_rx *tid_rx = timer_container_of(tid_rx, t,
                                                         session_timer);
        struct sta_info *sta = tid_rx->sta;
        u8 tid = tid_rx->tid;
        unsigned long timeout;

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

        ht_dbg(sta->sdata, "RX session timer expired on %pM tid %d\n",
               sta->sta.addr, tid);

        set_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired);
        wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
}

static void sta_rx_agg_reorder_timer_expired(struct timer_list *t)
{
        struct tid_ampdu_rx *tid_rx = timer_container_of(tid_rx, t,
                                                         reorder_timer);

        rcu_read_lock();
        ieee80211_release_reorder_timeout(tid_rx->sta, tid_rx->tid);
        rcu_read_unlock();
}

void ieee80211_add_addbaext(struct sk_buff *skb,
                            const u8 req_addba_ext_data,
                            u16 buf_size)
{
        struct ieee80211_addba_ext_ie *addba_ext;
        u8 *pos;

        pos = skb_put_zero(skb, 2 + sizeof(struct ieee80211_addba_ext_ie));
        *pos++ = WLAN_EID_ADDBA_EXT;
        *pos++ = sizeof(struct ieee80211_addba_ext_ie);
        addba_ext = (struct ieee80211_addba_ext_ie *)pos;

        addba_ext->data = IEEE80211_ADDBA_EXT_NO_FRAG;
        if (req_addba_ext_data)
                addba_ext->data &= req_addba_ext_data;

        addba_ext->data |=
                u8_encode_bits(buf_size >> IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT,
                               IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
}

u8 ieee80211_retrieve_addba_ext_data(struct sta_info *sta,
                                     const void *elem_data, ssize_t elem_len,
                                     u16 *buf_size)
{
        struct ieee802_11_elems *elems;
        u8 buf_size_1k, data = 0;

        if (!sta->sta.deflink.he_cap.has_he)
                return 0;

        if (elem_len <= 0)
                return 0;

        elems = ieee802_11_parse_elems(elem_data, elem_len,
                                       IEEE80211_FTYPE_MGMT |
                                       IEEE80211_STYPE_ACTION,
                                       NULL);

        if (!elems || elems->parse_error || !elems->addba_ext_ie)
                goto free;

        data = elems->addba_ext_ie->data;

        if (buf_size &&
            (sta->sta.valid_links || sta->sta.deflink.eht_cap.has_eht)) {
                buf_size_1k = u8_get_bits(elems->addba_ext_ie->data,
                                          IEEE80211_ADDBA_EXT_BUF_SIZE_MASK);
                *buf_size |= (u16)buf_size_1k <<
                             IEEE80211_ADDBA_EXT_BUF_SIZE_SHIFT;
        }

free:
        kfree(elems);

        return data;
}

static void ieee80211_send_addba_resp(struct sta_info *sta, u8 *da, u16 tid,
                                      u8 dialog_token, u16 status, u16 policy,
                                      u16 buf_size, u16 timeout,
                                      const u8 req_addba_ext_data)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        struct ieee80211_mgmt *mgmt;
        bool amsdu = ieee80211_hw_check(&local->hw, SUPPORTS_AMSDU_IN_AMPDU);
        bool use_ndp = ieee80211_s1g_use_ndp_ba(sdata, sta);
        u16 capab;

        skb = dev_alloc_skb(sizeof(*mgmt) +
                    2 + sizeof(struct ieee80211_addba_ext_ie) +
                    local->hw.extra_tx_headroom);
        if (!skb)
                return;

        skb_reserve(skb, local->hw.extra_tx_headroom);
        mgmt = ieee80211_mgmt_ba(skb, da, sdata);

        skb_put(skb, 2 + sizeof(mgmt->u.action.addba_resp));
        mgmt->u.action.category = WLAN_CATEGORY_BACK;
        mgmt->u.action.action_code = use_ndp ?
                WLAN_ACTION_NDP_ADDBA_RESP : WLAN_ACTION_ADDBA_RESP;

        mgmt->u.action.addba_resp.dialog_token = dialog_token;

        capab = u16_encode_bits(amsdu, IEEE80211_ADDBA_PARAM_AMSDU_MASK);
        capab |= u16_encode_bits(policy, IEEE80211_ADDBA_PARAM_POLICY_MASK);
        capab |= u16_encode_bits(tid, IEEE80211_ADDBA_PARAM_TID_MASK);
        capab |= u16_encode_bits(buf_size, IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK);

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

        if (sta->sta.valid_links || sta->sta.deflink.he_cap.has_he)
                ieee80211_add_addbaext(skb, req_addba_ext_data, buf_size);

        ieee80211_tx_skb(sdata, skb);
}

void __ieee80211_start_rx_ba_session(struct sta_info *sta,
                                     u8 dialog_token, u16 timeout,
                                     u16 start_seq_num, u16 ba_policy, u16 tid,
                                     u16 buf_size, bool tx, bool auto_seq,
                                     bool req_ndp,
                                     const u8 addba_ext_data)
{
        struct ieee80211_local *local = sta->sdata->local;
        struct tid_ampdu_rx *tid_agg_rx;
        struct ieee80211_ampdu_params params = {
                .sta = &sta->sta,
                .action = IEEE80211_AMPDU_RX_START,
                .tid = tid,
                .amsdu = false,
                .timeout = timeout,
                .ssn = start_seq_num,
        };
        int i, ret = -EOPNOTSUPP;
        u16 status = WLAN_STATUS_REQUEST_DECLINED;
        u16 max_buf_size;

        lockdep_assert_wiphy(sta->local->hw.wiphy);

        if (tid >= IEEE80211_FIRST_TSPEC_TSID) {
                ht_dbg(sta->sdata,
                       "STA %pM requests BA session on unsupported tid %d\n",
                       sta->sta.addr, tid);
                goto end;
        }

        if (tx && ieee80211_s1g_use_ndp_ba(sta->sdata, sta) && !req_ndp) {
                /*
                 * According to IEEE 802.11-2024: Inform S1G originator
                 * ADDBA rejected as NDP BlockAck is preferred
                 */
                status = WLAN_STATUS_REJECTED_NDP_BLOCK_ACK_SUGGESTED;
                ht_dbg(sta->sdata,
                       "Rejecting AddBA Req from %pM tid %u - require NDP BlockAck\n",
                       sta->sta.addr, tid);
                goto end;
        }

        if (!sta->sta.valid_links &&
            !sta->sta.deflink.ht_cap.ht_supported &&
            !sta->sta.deflink.he_cap.has_he &&
            !sta->sta.deflink.s1g_cap.s1g) {
                ht_dbg(sta->sdata,
                       "STA %pM erroneously requests BA session on tid %d w/o HT\n",
                       sta->sta.addr, tid);
                /* send a response anyway, it's an error case if we get here */
                goto end;
        }

        if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
                ht_dbg(sta->sdata,
                       "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
                       sta->sta.addr, tid);
                goto end;
        }

        if (sta->sta.valid_links || sta->sta.deflink.eht_cap.has_eht)
                max_buf_size = IEEE80211_MAX_AMPDU_BUF_EHT;
        else if (sta->sta.deflink.he_cap.has_he)
                max_buf_size = IEEE80211_MAX_AMPDU_BUF_HE;
        else
                max_buf_size = IEEE80211_MAX_AMPDU_BUF_HT;

        /* 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.valid_links ||
              !(sta->sta.deflink.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA) ||
              !(sta->sta.deflink.s1g_cap.cap[3] & S1G_CAP3_HT_DELAYED_BA))) ||
            (buf_size > max_buf_size)) {
                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",
                                   sta->sta.addr, tid, ba_policy, buf_size);
                goto end;
        }
        /* determine default buffer size */
        if (buf_size == 0)
                buf_size = max_buf_size;

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

        ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
               buf_size, sta->sta.addr);

        if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
                if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
                        struct tid_ampdu_rx *tid_rx;

                        ht_dbg_ratelimited(sta->sdata,
                                           "updated AddBA Req from %pM on tid %u\n",
                                           sta->sta.addr, tid);
                        /* We have no API to update the timeout value in the
                         * driver so reject the timeout update if the timeout
                         * changed. If it did not change, i.e., no real update,
                         * just reply with success.
                         */
                        rcu_read_lock();
                        tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
                        if (tid_rx && tid_rx->timeout == timeout)
                                status = WLAN_STATUS_SUCCESS;
                        else
                                status = WLAN_STATUS_REQUEST_DECLINED;
                        rcu_read_unlock();
                        goto end;
                }

                ht_dbg_ratelimited(sta->sdata,
                                   "unexpected AddBA Req from %pM on tid %u\n",
                                   sta->sta.addr, 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);
        }

        if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
                ret = drv_ampdu_action(local, sta->sdata, &params);
                ht_dbg(sta->sdata,
                       "Rx A-MPDU request on %pM tid %d result %d\n",
                       sta->sta.addr, tid, ret);
                if (!ret)
                        status = WLAN_STATUS_SUCCESS;
                goto end;
        }

        /* prepare A-MPDU MLME for Rx aggregation */
        tid_agg_rx = kzalloc_flex(*tid_agg_rx, reorder, buf_size);
        if (!tid_agg_rx)
                goto end;

        spin_lock_init(&tid_agg_rx->reorder_lock);

        /* rx timer */
        timer_setup(&tid_agg_rx->session_timer,
                    sta_rx_agg_session_timer_expired, TIMER_DEFERRABLE);

        /* rx reorder timer */
        timer_setup(&tid_agg_rx->reorder_timer,
                    sta_rx_agg_reorder_timer_expired, 0);

        for (i = 0; i < buf_size; i++)
                __skb_queue_head_init(&tid_agg_rx->reorder[i].buf);

        ret = drv_ampdu_action(local, sta->sdata, &params);
        ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
               sta->sta.addr, tid, ret);
        if (ret) {
                kfree(tid_agg_rx);
                goto end;
        }

        /* update data */
        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;
        tid_agg_rx->auto_seq = auto_seq;
        tid_agg_rx->started = false;
        tid_agg_rx->reorder_buf_filtered = 0;
        tid_agg_rx->tid = tid;
        tid_agg_rx->sta = sta;
        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:
        if (status == WLAN_STATUS_SUCCESS) {
                __set_bit(tid, sta->ampdu_mlme.agg_session_valid);
                __clear_bit(tid, sta->ampdu_mlme.unexpected_agg);
                sta->ampdu_mlme.tid_rx_token[tid] = dialog_token;
        }

        if (tx)
                ieee80211_send_addba_resp(sta, sta->sta.addr, tid,
                                          dialog_token, status, 1, buf_size,
                                          timeout, addba_ext_data);
}

void ieee80211_process_addba_request(struct ieee80211_local *local,
                                     struct sta_info *sta,
                                     struct ieee80211_mgmt *mgmt,
                                     size_t len)
{
        bool req_ndp = mgmt->u.action.action_code == WLAN_ACTION_NDP_ADDBA_REQ;
        u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num;
        u8 dialog_token, addba_ext_data;

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

        capab = le16_to_cpu(mgmt->u.action.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;

        addba_ext_data =
                ieee80211_retrieve_addba_ext_data(sta,
                                                  mgmt->u.action.addba_req.variable,
                                                  len -
                                                  offsetof(typeof(*mgmt),
                                                           u.action.addba_req.variable),
                                                  &buf_size);

        __ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
                                        start_seq_num, ba_policy, tid,
                                        buf_size, true, false,
                                        req_ndp, addba_ext_data);
}

void ieee80211_manage_rx_ba_offl(struct ieee80211_vif *vif,
                                 const u8 *addr, unsigned int tid)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
        struct sta_info *sta;

        rcu_read_lock();
        sta = sta_info_get_bss(sdata, addr);
        if (!sta)
                goto unlock;

        set_bit(tid, sta->ampdu_mlme.tid_rx_manage_offl);
        wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);
 unlock:
        rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_manage_rx_ba_offl);

void ieee80211_rx_ba_timer_expired(struct ieee80211_vif *vif,
                                   const u8 *addr, unsigned int tid)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
        struct sta_info *sta;

        rcu_read_lock();
        sta = sta_info_get_bss(sdata, addr);
        if (!sta)
                goto unlock;

        set_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired);
        wiphy_work_queue(sta->local->hw.wiphy, &sta->ampdu_mlme.work);

 unlock:
        rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_rx_ba_timer_expired);