/*
   * Copyright 2007-2012 Siemens AG
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *

   * Written by:
   * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
   * Sergey Lapin <slapin@ossfans.org>
   * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
   * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
   */
  
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/crc-ccitt.h>

  #include <asm/unaligned.h>

  #include <net/rtnetlink.h>

  #include <net/ieee802154_netdev.h>

  #include <net/mac802154.h>

  #include <net/cfg802154.h>

  #include "ieee802154_i.h"

  #include "driver-ops.h"

  void ieee802154_xmit_worker(struct work_struct *work)

  {

  	struct ieee802154_local *local =
  		container_of(work, struct ieee802154_local, tx_work);
  	struct sk_buff *skb = local->tx_skb;

  	struct net_device *dev = skb->dev;

  	int res;

  	res = drv_xmit_sync(local, skb);

  	if (res)
  		goto err_tx;

  	ieee802154_xmit_complete(&local->hw, skb, false);

  	dev->stats.tx_packets++;
  	dev->stats.tx_bytes += skb->len;

  	return;
  
  err_tx:
  	/* Restart the netif queue on each sub_if_data object. */
  	ieee802154_wake_queue(&local->hw);

  	kfree_skb(skb);

  	netdev_dbg(dev, "transmission failed
  ");

  }

  static netdev_tx_t

  ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)

  {

  	struct net_device *dev = skb->dev;

  	int ret;

  	if (!(local->hw.flags & IEEE802154_HW_TX_OMIT_CKSUM)) {

  		struct sk_buff *nskb;
  		u16 crc;

  		if (unlikely(skb_tailroom(skb) < IEEE802154_FCS_LEN)) {
  			nskb = skb_copy_expand(skb, 0, IEEE802154_FCS_LEN,
  					       GFP_ATOMIC);
  			if (likely(nskb)) {
  				consume_skb(skb);
  				skb = nskb;
  			} else {
  				goto err_tx;
  			}
  		}
  
  		crc = crc_ccitt(0, skb->data, skb->len);

  		put_unaligned_le16(crc, skb_put(skb, 2));

  	}

  	/* Stop the netif queue on each sub_if_data object. */

  	ieee802154_stop_queue(&local->hw);

  	/* async is priority, otherwise sync is fallback */
  	if (local->ops->xmit_async) {

  		ret = drv_xmit_async(local, skb);

  		if (ret) {
  			ieee802154_wake_queue(&local->hw);
  			goto err_tx;
  		}

  
  		dev->stats.tx_packets++;
  		dev->stats.tx_bytes += skb->len;

  	} else {

  		local->tx_skb = skb;
  		queue_work(local->workqueue, &local->tx_work);

  	}

  
  	return NETDEV_TX_OK;

  
  err_tx:
  	kfree_skb(skb);
  	return NETDEV_TX_OK;

  }

  netdev_tx_t
  ieee802154_monitor_start_xmit(struct sk_buff *skb, struct net_device *dev)

  {
  	struct ieee802154_sub_if_data *sdata = IEEE802154_DEV_TO_SUB_IF(dev);

  
  	skb->skb_iif = dev->ifindex;

  	return ieee802154_tx(sdata->local, skb);

  }

  netdev_tx_t
  ieee802154_subif_start_xmit(struct sk_buff *skb, struct net_device *dev)

  {
  	struct ieee802154_sub_if_data *sdata = IEEE802154_DEV_TO_SUB_IF(dev);

  	int rc;

  	/* TODO we should move it to wpan_dev_hard_header and dev_hard_header
  	 * functions. The reason is wireshark will show a mac header which is
  	 * with security fields but the payload is not encrypted.
  	 */

  	rc = mac802154_llsec_encrypt(&sdata->sec, skb);
  	if (rc) {

  		netdev_warn(dev, "encryption failed: %i
  ", rc);

  		kfree_skb(skb);
  		return NETDEV_TX_OK;
  	}
  
  	skb->skb_iif = dev->ifindex;

  	return ieee802154_tx(sdata->local, skb);

  }