/*
 * Marvell Wireless LAN device driver: AP TX and RX data handling
 *
 * Copyright (C) 2012, Marvell International Ltd.
 *
 * This software file (the "File") is distributed by Marvell International
 * Ltd. under the terms of the GNU General Public License Version 2, June 1991
 * (the "License").  You may use, redistribute and/or modify this File in
 * accordance with the terms and conditions of the License, a copy of which
 * is available by writing to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or on the
 * worldwide web at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
 *
 * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
 * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
 * this warranty disclaimer.
 */

#include "decl.h"
#include "ioctl.h"
#include "main.h"
#include "wmm.h"
#include "11n_aggr.h"
#include "11n_rxreorder.h"

/* This function checks if particular RA list has packets more than low bridge
 * packet threshold and then deletes packet from this RA list.
 * Function deletes packets from such RA list and returns true. If no such list
 * is found, false is returned.
 */
static bool
mwifiex_uap_del_tx_pkts_in_ralist(struct mwifiex_private *priv,
                                  struct list_head *ra_list_head)
{
        struct mwifiex_ra_list_tbl *ra_list;
        struct sk_buff *skb, *tmp;
        bool pkt_deleted = false;
        struct mwifiex_txinfo *tx_info;
        struct mwifiex_adapter *adapter = priv->adapter;

        list_for_each_entry(ra_list, ra_list_head, list) {
                if (skb_queue_empty(&ra_list->skb_head))
                        continue;

                skb_queue_walk_safe(&ra_list->skb_head, skb, tmp) {
                        tx_info = MWIFIEX_SKB_TXCB(skb);
                        if (tx_info->flags & MWIFIEX_BUF_FLAG_BRIDGED_PKT) {
                                __skb_unlink(skb, &ra_list->skb_head);
                                mwifiex_write_data_complete(adapter, skb, 0,
                                                            -1);
                                atomic_dec(&priv->wmm.tx_pkts_queued);
                                pkt_deleted = true;
                        }
                        if ((atomic_read(&adapter->pending_bridged_pkts) <=
                                             MWIFIEX_BRIDGED_PKTS_THR_LOW))
                                break;
                }
        }

        return pkt_deleted;
}

/* This function deletes packets from particular RA List. RA list index
 * from which packets are deleted is preserved so that packets from next RA
 * list are deleted upon subsequent call thus maintaining fairness.
 */
static void mwifiex_uap_cleanup_tx_queues(struct mwifiex_private *priv)
{
        unsigned long flags;
        struct list_head *ra_list;
        int i;

        spin_lock_irqsave(&priv->wmm.ra_list_spinlock, flags);

        for (i = 0; i < MAX_NUM_TID; i++, priv->del_list_idx++) {
                if (priv->del_list_idx == MAX_NUM_TID)
                        priv->del_list_idx = 0;
                ra_list = &priv->wmm.tid_tbl_ptr[priv->del_list_idx].ra_list;
                if (mwifiex_uap_del_tx_pkts_in_ralist(priv, ra_list)) {
                        priv->del_list_idx++;
                        break;
                }
        }

        spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, flags);
}


static void mwifiex_uap_queue_bridged_pkt(struct mwifiex_private *priv,
                                         struct sk_buff *skb)
{
        struct mwifiex_adapter *adapter = priv->adapter;
        struct uap_rxpd *uap_rx_pd;
        struct rx_packet_hdr *rx_pkt_hdr;
        struct sk_buff *new_skb;
        struct mwifiex_txinfo *tx_info;
        int hdr_chop;
        struct timeval tv;
        u8 rfc1042_eth_hdr[ETH_ALEN] = { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };

        uap_rx_pd = (struct uap_rxpd *)(skb->data);
        rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);

        if ((atomic_read(&adapter->pending_bridged_pkts) >=
                                             MWIFIEX_BRIDGED_PKTS_THR_HIGH)) {
                dev_err(priv->adapter->dev,
                        "Tx: Bridge packet limit reached. Drop packet!\n");
                kfree_skb(skb);
                mwifiex_uap_cleanup_tx_queues(priv);
                return;
        }

        if (!memcmp(&rx_pkt_hdr->rfc1042_hdr,
                    rfc1042_eth_hdr, sizeof(rfc1042_eth_hdr)))
                /* Chop off the rxpd + the excess memory from
                 * 802.2/llc/snap header that was removed.
                 */
                hdr_chop = (u8 *)eth_hdr - (u8 *)uap_rx_pd;
        else
                /* Chop off the rxpd */
                hdr_chop = (u8 *)&rx_pkt_hdr->eth803_hdr - (u8 *)uap_rx_pd;

        /* Chop off the leading header bytes so the it points
         * to the start of either the reconstructed EthII frame
         * or the 802.2/llc/snap frame.
         */
        skb_pull(skb, hdr_chop);

        if (skb_headroom(skb) < MWIFIEX_MIN_DATA_HEADER_LEN) {
                dev_dbg(priv->adapter->dev,
                        "data: Tx: insufficient skb headroom %d\n",
                        skb_headroom(skb));
                /* Insufficient skb headroom - allocate a new skb */
                new_skb =
                        skb_realloc_headroom(skb, MWIFIEX_MIN_DATA_HEADER_LEN);
                if (unlikely(!new_skb)) {
                        dev_err(priv->adapter->dev,
                                "Tx: cannot allocate new_skb\n");
                        kfree_skb(skb);
                        priv->stats.tx_dropped++;
                        return;
                }

                kfree_skb(skb);
                skb = new_skb;
                dev_dbg(priv->adapter->dev, "info: new skb headroom %d\n",
                        skb_headroom(skb));
        }

        tx_info = MWIFIEX_SKB_TXCB(skb);
        tx_info->bss_num = priv->bss_num;
        tx_info->bss_type = priv->bss_type;
        tx_info->flags |= MWIFIEX_BUF_FLAG_BRIDGED_PKT;

        do_gettimeofday(&tv);
        skb->tstamp = timeval_to_ktime(tv);
        mwifiex_wmm_add_buf_txqueue(priv, skb);
        atomic_inc(&adapter->tx_pending);
        atomic_inc(&adapter->pending_bridged_pkts);

        return;
}

/*
 * This function contains logic for AP packet forwarding.
 *
 * If a packet is multicast/broadcast, it is sent to kernel/upper layer
 * as well as queued back to AP TX queue so that it can be sent to other
 * associated stations.
 * If a packet is unicast and RA is present in associated station list,
 * it is again requeued into AP TX queue.
 * If a packet is unicast and RA is not in associated station list,
 * packet is forwarded to kernel to handle routing logic.
 */
int mwifiex_handle_uap_rx_forward(struct mwifiex_private *priv,
                                  struct sk_buff *skb)
{
        struct mwifiex_adapter *adapter = priv->adapter;
        struct uap_rxpd *uap_rx_pd;
        struct rx_packet_hdr *rx_pkt_hdr;
        u8 ra[ETH_ALEN];
        struct sk_buff *skb_uap;

        uap_rx_pd = (struct uap_rxpd *)(skb->data);
        rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);

        /* don't do packet forwarding in disconnected state */
        if (!priv->media_connected) {
                dev_err(adapter->dev, "drop packet in disconnected state.\n");
                dev_kfree_skb_any(skb);
                return 0;
        }

        memcpy(ra, rx_pkt_hdr->eth803_hdr.h_dest, ETH_ALEN);

        if (is_multicast_ether_addr(ra)) {
                skb_uap = skb_copy(skb, GFP_ATOMIC);
                mwifiex_uap_queue_bridged_pkt(priv, skb_uap);
        } else {
                if (mwifiex_get_sta_entry(priv, ra)) {
                        /* Requeue Intra-BSS packet */
                        mwifiex_uap_queue_bridged_pkt(priv, skb);
                        return 0;
                }
        }

        /* Forward unicat/Inter-BSS packets to kernel. */
        return mwifiex_process_rx_packet(priv, skb);
}

/*
 * This function processes the packet received on AP interface.
 *
 * The function looks into the RxPD and performs sanity tests on the
 * received buffer to ensure its a valid packet before processing it
 * further. If the packet is determined to be aggregated, it is
 * de-aggregated accordingly. Then skb is passed to AP packet forwarding logic.
 *
 * The completion callback is called after processing is complete.
 */
int mwifiex_process_uap_rx_packet(struct mwifiex_private *priv,
                                  struct sk_buff *skb)
{
        struct mwifiex_adapter *adapter = priv->adapter;
        int ret;
        struct uap_rxpd *uap_rx_pd;
        struct rx_packet_hdr *rx_pkt_hdr;
        u16 rx_pkt_type;
        u8 ta[ETH_ALEN], pkt_type;
        struct mwifiex_sta_node *node;

        uap_rx_pd = (struct uap_rxpd *)(skb->data);
        rx_pkt_type = le16_to_cpu(uap_rx_pd->rx_pkt_type);
        rx_pkt_hdr = (void *)uap_rx_pd + le16_to_cpu(uap_rx_pd->rx_pkt_offset);

        if ((le16_to_cpu(uap_rx_pd->rx_pkt_offset) +
             le16_to_cpu(uap_rx_pd->rx_pkt_length)) > (u16) skb->len) {
                dev_err(adapter->dev,
                        "wrong rx packet: len=%d, offset=%d, length=%d\n",
                        skb->len, le16_to_cpu(uap_rx_pd->rx_pkt_offset),
                        le16_to_cpu(uap_rx_pd->rx_pkt_length));
                priv->stats.rx_dropped++;

                if (adapter->if_ops.data_complete)
                        adapter->if_ops.data_complete(adapter, skb);
                else
                        dev_kfree_skb_any(skb);

                return 0;
        }

        if (le16_to_cpu(uap_rx_pd->rx_pkt_type) == PKT_TYPE_AMSDU) {
                struct sk_buff_head list;
                struct sk_buff *rx_skb;

                __skb_queue_head_init(&list);
                skb_pull(skb, le16_to_cpu(uap_rx_pd->rx_pkt_offset));
                skb_trim(skb, le16_to_cpu(uap_rx_pd->rx_pkt_length));

                ieee80211_amsdu_to_8023s(skb, &list, priv->curr_addr,
                                         priv->wdev->iftype, 0, false);

                while (!skb_queue_empty(&list)) {
                        rx_skb = __skb_dequeue(&list);
                        ret = mwifiex_recv_packet(priv, rx_skb);
                        if (ret)
                                dev_err(adapter->dev,
                                        "AP:Rx A-MSDU failed");
                }

                return 0;
        } else if (rx_pkt_type == PKT_TYPE_MGMT) {
                ret = mwifiex_process_mgmt_packet(priv, skb);
                if (ret)
                        dev_err(adapter->dev, "Rx of mgmt packet failed");
                dev_kfree_skb_any(skb);
                return ret;
        }

        memcpy(ta, rx_pkt_hdr->eth803_hdr.h_source, ETH_ALEN);

        if (rx_pkt_type != PKT_TYPE_BAR && uap_rx_pd->priority < MAX_NUM_TID) {
                node = mwifiex_get_sta_entry(priv, ta);
                if (node)
                        node->rx_seq[uap_rx_pd->priority] =
                                                le16_to_cpu(uap_rx_pd->seq_num);
        }

        if (!priv->ap_11n_enabled ||
            (!mwifiex_11n_get_rx_reorder_tbl(priv, uap_rx_pd->priority, ta) &&
            (le16_to_cpu(uap_rx_pd->rx_pkt_type) != PKT_TYPE_AMSDU))) {
                ret = mwifiex_handle_uap_rx_forward(priv, skb);
                return ret;
        }

        /* Reorder and send to kernel */
        pkt_type = (u8)le16_to_cpu(uap_rx_pd->rx_pkt_type);
        ret = mwifiex_11n_rx_reorder_pkt(priv, le16_to_cpu(uap_rx_pd->seq_num),
                                         uap_rx_pd->priority, ta, pkt_type,
                                         skb);

        if (ret || (rx_pkt_type == PKT_TYPE_BAR)) {
                if (adapter->if_ops.data_complete)
                        adapter->if_ops.data_complete(adapter, skb);
                else
                        dev_kfree_skb_any(skb);
        }

        if (ret)
                priv->stats.rx_dropped++;

        return ret;
}

/*
 * This function fills the TxPD for AP tx packets.
 *
 * The Tx buffer received by this function should already have the
 * header space allocated for TxPD.
 *
 * This function inserts the TxPD in between interface header and actual
 * data and adjusts the buffer pointers accordingly.
 *
 * The following TxPD fields are set by this function, as required -
 *      - BSS number
 *      - Tx packet length and offset
 *      - Priority
 *      - Packet delay
 *      - Priority specific Tx control
 *      - Flags
 */
void *mwifiex_process_uap_txpd(struct mwifiex_private *priv,
                               struct sk_buff *skb)
{
        struct mwifiex_adapter *adapter = priv->adapter;
        struct uap_txpd *txpd;
        struct mwifiex_txinfo *tx_info = MWIFIEX_SKB_TXCB(skb);
        int pad, len;
        u16 pkt_type;

        if (!skb->len) {
                dev_err(adapter->dev, "Tx: bad packet length: %d\n", skb->len);
                tx_info->status_code = -1;
                return skb->data;
        }

        pkt_type = mwifiex_is_skb_mgmt_frame(skb) ? PKT_TYPE_MGMT : 0;

        /* If skb->data is not aligned, add padding */
        pad = (4 - (((void *)skb->data - NULL) & 0x3)) % 4;

        len = sizeof(*txpd) + pad;

        BUG_ON(skb_headroom(skb) < len + INTF_HEADER_LEN);

        skb_push(skb, len);

        txpd = (struct uap_txpd *)skb->data;
        memset(txpd, 0, sizeof(*txpd));
        txpd->bss_num = priv->bss_num;
        txpd->bss_type = priv->bss_type;
        txpd->tx_pkt_length = cpu_to_le16((u16)(skb->len - len));

        txpd->priority = (u8)skb->priority;
        txpd->pkt_delay_2ms = mwifiex_wmm_compute_drv_pkt_delay(priv, skb);

        if (txpd->priority < ARRAY_SIZE(priv->wmm.user_pri_pkt_tx_ctrl))
                /*
                 * Set the priority specific tx_control field, setting of 0 will
                 * cause the default value to be used later in this function.
                 */
                txpd->tx_control =
                    cpu_to_le32(priv->wmm.user_pri_pkt_tx_ctrl[txpd->priority]);

        /* Offset of actual data */
        if (pkt_type == PKT_TYPE_MGMT) {
                /* Set the packet type and add header for management frame */
                txpd->tx_pkt_type = cpu_to_le16(pkt_type);
                len += MWIFIEX_MGMT_FRAME_HEADER_SIZE;
        }

        txpd->tx_pkt_offset = cpu_to_le16(len);

        /* make space for INTF_HEADER_LEN */
        skb_push(skb, INTF_HEADER_LEN);

        if (!txpd->tx_control)
                /* TxCtrl set by user or default */
                txpd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);

        return skb->data;
}