net/mac802154/rx.c

   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  */
  46 struct rx_work {
  47         struct sk_buff *skb;
  48         struct work_struct work;
  49         struct ieee802154_dev *dev;
  50         u8 lqi;
  51 };
  52
  53 static void
  54 mac802154_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);
  81 out:
  82         dev_kfree_skb(skb);
  83         return;
  84 }
  85
  86 static 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
  95 void
  96 ieee802154_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 }
 115 EXPORT_SYMBOL(ieee802154_rx_irqsafe);