mac802154: monitor device support

Support for monitor device intended to capture all the network activity.
This interface could be used by networks sniffers and is already
supported by WireShark. That's a good test point to check that basic
MAC support works.

Signed-off-by: Alexander Smirnov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/if_arp.h

···
 #define ARPHRD_IEEE80211_PRISM 802	/* IEEE 802.11 + Prism2 header  */
 #define ARPHRD_IEEE80211_RADIOTAP 803	/* IEEE 802.11 + radiotap header */
 #define ARPHRD_IEEE802154	  804
+#define ARPHRD_IEEE802154_MONITOR 805	/* IEEE 802.15.4 network monitor */
 
 #define ARPHRD_PHONET	820		/* PhoNet media type		*/
 #define ARPHRD_PHONET_PIPE 821		/* PhoNet pipe header		*/

include/linux/nl802154.h

···
 
 enum {
 	__IEEE802154_DEV_INVALID = -1,
+
+	 /* TODO:
+	 * Nowadays three device types supported by this stack at linux-zigbee
+	 * project: WPAN = 0, MONITOR = 1 and SMAC = 2.
+	 *
+	 * Since this stack implementation exists many years, it's definitely
+	 * bad idea to change the assigned values due to they are already used
+	 * by third-party userspace software like: iz-tools, wireshark...
+	 *
+	 * Currently only monitor device is added and initialized by '1' for
+	 * compatibility.
+	 */
+	IEEE802154_DEV_MONITOR = 1,
+
 	__IEEE802154_DEV_MAX,
 };
 

include/net/wpan-phy.h

···
 #include <linux/mutex.h>
 #include <linux/bug.h>
 
+/* According to the IEEE 802.15.4 stadard the upper most significant bits of
+ * the 32-bit channel bitmaps shall be used as an integer value to specify 32
+ * possible channel pages. The lower 27 bits of the channel bit map shall be
+ * used as a bit mask to specify channel numbers within a channel page.
+ */
+#define WPAN_NUM_CHANNELS	27
+#define WPAN_NUM_PAGES		32
+
 struct wpan_phy {
 	struct mutex pib_lock;
 

net/mac802154/Makefile

···
 obj-$(CONFIG_MAC802154)	+= mac802154.o
-mac802154-objs		:= ieee802154_dev.o rx.o tx.o mac_cmd.o mib.o
+mac802154-objs		:= ieee802154_dev.o rx.o tx.o mac_cmd.o mib.o monitor.o

net/mac802154/ieee802154_dev.c

···
 	struct net_device *dev;
 	int err = -ENOMEM;
 
-	/* No devices is currently added */
 	switch (type) {
+	case IEEE802154_DEV_MONITOR:
+		dev = alloc_netdev(sizeof(struct mac802154_sub_if_data),
+				   name, mac802154_monitor_setup);
+		break;
 	default:
 		dev = NULL;
 		err = -EINVAL;

net/mac802154/mac802154.h

···
 
 #define MAC802154_MAX_XMIT_ATTEMPTS	3
 
+#define MAC802154_CHAN_NONE		(~(u8)0) /* No channel is assigned */
+
 extern struct ieee802154_reduced_mlme_ops mac802154_mlme_reduced;
 
 int mac802154_slave_open(struct net_device *dev);
 int mac802154_slave_close(struct net_device *dev);
+
+void mac802154_monitors_rx(struct mac802154_priv *priv, struct sk_buff *skb);
+void mac802154_monitor_setup(struct net_device *dev);
 
 netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
 			 u8 page, u8 chan);

net/mac802154/monitor.c

···
+/*
+ * Copyright 2007, 2008, 2009 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Written by:
+ * Dmitry Eremin-Solenikov <[e-mail]>
+ * Sergey Lapin <[e-mail]>
+ * Maxim Gorbachyov <[e-mail]>
+ * Alexander Smirnov <[e-mail]>
+ */
+
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/crc-ccitt.h>
+
+#include <net/ieee802154.h>
+#include <net/mac802154.h>
+#include <net/netlink.h>
+#include <net/wpan-phy.h>
+#include <linux/nl802154.h>
+
+#include "mac802154.h"
+
+static netdev_tx_t mac802154_monitor_xmit(struct sk_buff *skb,
+					  struct net_device *dev)
+{
+	struct mac802154_sub_if_data *priv;
+	u8 chan, page;
+
+	priv = netdev_priv(dev);
+
+	/* FIXME: locking */
+	chan = priv->hw->phy->current_channel;
+	page = priv->hw->phy->current_page;
+
+	if (chan == MAC802154_CHAN_NONE) /* not initialized */
+		return NETDEV_TX_OK;
+
+	if (WARN_ON(page >= WPAN_NUM_PAGES) ||
+	    WARN_ON(chan >= WPAN_NUM_CHANNELS))
+		return NETDEV_TX_OK;
+
+	skb->skb_iif = dev->ifindex;
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+
+	return mac802154_tx(priv->hw, skb, page, chan);
+}
+
+
+void mac802154_monitors_rx(struct mac802154_priv *priv, struct sk_buff *skb)
+{
+	struct sk_buff *skb2;
+	struct mac802154_sub_if_data *sdata;
+	u16 crc = crc_ccitt(0, skb->data, skb->len);
+	u8 *data;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &priv->slaves, list) {
+		if (sdata->type != IEEE802154_DEV_MONITOR)
+			continue;
+
+		skb2 = skb_clone(skb, GFP_ATOMIC);
+		skb2->dev = sdata->dev;
+		skb2->pkt_type = PACKET_HOST;
+		data = skb_put(skb2, 2);
+		data[0] = crc & 0xff;
+		data[1] = crc >> 8;
+
+		netif_rx_ni(skb2);
+	}
+	rcu_read_unlock();
+}
+
+static const struct net_device_ops mac802154_monitor_ops = {
+	.ndo_open		= mac802154_slave_open,
+	.ndo_stop		= mac802154_slave_close,
+	.ndo_start_xmit		= mac802154_monitor_xmit,
+};
+
+void mac802154_monitor_setup(struct net_device *dev)
+{
+	struct mac802154_sub_if_data *priv;
+
+	dev->addr_len		= 0;
+	dev->hard_header_len	= 0;
+	dev->needed_tailroom	= 2; /* room for FCS */
+	dev->mtu		= IEEE802154_MTU;
+	dev->tx_queue_len	= 10;
+	dev->type		= ARPHRD_IEEE802154_MONITOR;
+	dev->flags		= IFF_NOARP | IFF_BROADCAST;
+	dev->watchdog_timeo	= 0;
+
+	dev->destructor		= free_netdev;
+	dev->netdev_ops		= &mac802154_monitor_ops;
+	dev->ml_priv		= &mac802154_mlme_reduced;
+
+	priv = netdev_priv(dev);
+	priv->type = IEEE802154_DEV_MONITOR;
+
+	priv->chan = MAC802154_CHAN_NONE; /* not initialized */
+	priv->page = 0;
+}

net/mac802154/rx.c

···
 		skb_trim(skb, skb->len - 2); /* CRC */
 	}
 
+	mac802154_monitors_rx(priv, skb);
 out:
 	dev_kfree_skb(skb);
 	return;