linux/net/mac802154/rx.c
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   1/*
   2 * Copyright (C) 2007-2012 Siemens AG
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2
   6 * as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along
  14 * with this program; if not, write to the Free Software Foundation, Inc.,
  15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16 *
  17 * Written by:
  18 * Pavel Smolenskiy <pavel.smolenskiy@gmail.com>
  19 * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
  20 * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
  21 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
  22 */
  23
  24#include <linux/kernel.h>
  25#include <linux/module.h>
  26#include <linux/workqueue.h>
  27#include <linux/netdevice.h>
  28#include <linux/crc-ccitt.h>
  29
  30#include <net/mac802154.h>
  31#include <net/ieee802154_netdev.h>
  32
  33#include "mac802154.h"
  34
  35/* The IEEE 802.15.4 standard defines 4 MAC packet types:
  36 * - beacon frame
  37 * - MAC command frame
  38 * - acknowledgement frame
  39 * - data frame
  40 *
  41 * and only the data frame should be pushed to the upper layers, other types
  42 * are just internal MAC layer management information. So only data packets
  43 * are going to be sent to the networking queue, all other will be processed
  44 * right here by using the device workqueue.
  45 */
  46struct rx_work {
  47        struct sk_buff *skb;
  48        struct work_struct work;
  49        struct ieee802154_dev *dev;
  50        u8 lqi;
  51};
  52
  53static void
  54mac802154_subif_rx(struct ieee802154_dev *hw, struct sk_buff *skb, u8 lqi)
  55{
  56        struct mac802154_priv *priv = mac802154_to_priv(hw);
  57
  58        mac_cb(skb)->lqi = lqi;
  59        skb->protocol = htons(ETH_P_IEEE802154);
  60        skb_reset_mac_header(skb);
  61
  62        BUILD_BUG_ON(sizeof(struct ieee802154_mac_cb) > sizeof(skb->cb));
  63
  64        if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
  65                u16 crc;
  66
  67                if (skb->len < 2) {
  68                        pr_debug("got invalid frame\n");
  69                        goto out;
  70                }
  71                crc = crc_ccitt(0, skb->data, skb->len);
  72                if (crc) {
  73                        pr_debug("CRC mismatch\n");
  74                        goto out;
  75                }
  76                skb_trim(skb, skb->len - 2); /* CRC */
  77        }
  78
  79        mac802154_monitors_rx(priv, skb);
  80        mac802154_wpans_rx(priv, skb);
  81out:
  82        dev_kfree_skb(skb);
  83        return;
  84}
  85
  86static void mac802154_rx_worker(struct work_struct *work)
  87{
  88        struct rx_work *rw = container_of(work, struct rx_work, work);
  89        struct sk_buff *skb = rw->skb;
  90
  91        mac802154_subif_rx(rw->dev, skb, rw->lqi);
  92        kfree(rw);
  93}
  94
  95void
  96ieee802154_rx_irqsafe(struct ieee802154_dev *dev, struct sk_buff *skb, u8 lqi)
  97{
  98        struct mac802154_priv *priv = mac802154_to_priv(dev);
  99        struct rx_work *work;
 100
 101        if (!skb)
 102                return;
 103
 104        work = kzalloc(sizeof(struct rx_work), GFP_ATOMIC);
 105        if (!work)
 106                return;
 107
 108        INIT_WORK(&work->work, mac802154_rx_worker);
 109        work->skb = skb;
 110        work->dev = dev;
 111        work->lqi = lqi;
 112
 113        queue_work(priv->dev_workqueue, &work->work);
 114}
 115EXPORT_SYMBOL(ieee802154_rx_irqsafe);
 116
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