/*
 * 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;
	struct ethhdr *p_ethhdr;

	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, bridge_tunnel_header,
		     sizeof(bridge_tunnel_header))) ||
	    (!memcmp(&rx_pkt_hdr->rfc1042_hdr, rfc1042_header,
		     sizeof(rfc1042_header)) &&
	     ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_AARP &&
	     ntohs(rx_pkt_hdr->rfc1042_hdr.snap_type) != ETH_P_IPX)) {
		/* Replace the 803 header and rfc1042 header (llc/snap) with
		 * an Ethernet II header, keep the src/dst and snap_type
		 * (ethertype).
		 *
		 * The firmware only passes up SNAP frames converting all RX
		 * data from 802.11 to 802.2/LLC/SNAP frames.
		 *
		 * To create the Ethernet II, just move the src, dst address
		 * right before the snap_type.
		 */
		p_ethhdr = (struct ethhdr *)
			((u8 *)(&rx_pkt_hdr->eth803_hdr)
			 + sizeof(rx_pkt_hdr->eth803_hdr)
			 + sizeof(rx_pkt_hdr->rfc1042_hdr)
			 - sizeof(rx_pkt_hdr->eth803_hdr.h_dest)
			 - sizeof(rx_pkt_hdr->eth803_hdr.h_source)
			 - sizeof(rx_pkt_hdr->rfc1042_hdr.snap_type));
		memcpy(p_ethhdr->h_source, rx_pkt_hdr->eth803_hdr.h_source,
		       sizeof(p_ethhdr->h_source));
		memcpy(p_ethhdr->h_dest, rx_pkt_hdr->eth803_hdr.h_dest,
		       sizeof(p_ethhdr->h_dest));
		/* Chop off the rxpd + the excess memory from
		 * 802.2/llc/snap header that was removed.
		 */
		hdr_chop = (u8 *)p_ethhdr - (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 that 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;

	if (is_unicast_ether_addr(rx_pkt_hdr->eth803_hdr.h_dest)) {
		/* Update bridge packet statistics as the
		 * packet is not going to kernel/upper layer.
		 */
		priv->stats.rx_bytes += skb->len;
		priv->stats.rx_packets++;

		/* Sending bridge packet to TX queue, so save the packet
		 * length in TXCB to update statistics in TX complete.
		 */
		tx_info->pkt_len = skb->len;
	}

	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++;
		dev_kfree_skb_any(skb);
		return 0;
	}

	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))
		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;
}