6lowpan.c 31.1 KB
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/*
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   Copyright (c) 2013-2014 Intel Corp.
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   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 and
   only 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.
*/

#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
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#include <linux/module.h>
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#include <linux/debugfs.h>
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#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>

#include <net/af_ieee802154.h> /* to get the address type */

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/l2cap.h>

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#include <net/6lowpan.h> /* for the compression support */
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#define VERSION "0.1"

static struct dentry *lowpan_psm_debugfs;
static struct dentry *lowpan_control_debugfs;

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#define IFACE_NAME_TEMPLATE "bt%d"
#define EUI64_ADDR_LEN 8

struct skb_cb {
	struct in6_addr addr;
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	struct in6_addr gw;
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	struct l2cap_chan *chan;
	int status;
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};
#define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))

/* The devices list contains those devices that we are acting
 * as a proxy. The BT 6LoWPAN device is a virtual device that
 * connects to the Bluetooth LE device. The real connection to
 * BT device is done via l2cap layer. There exists one
 * virtual device / one BT 6LoWPAN network (=hciX device).
 * The list contains struct lowpan_dev elements.
 */
static LIST_HEAD(bt_6lowpan_devices);
static DEFINE_RWLOCK(devices_lock);

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/* If psm is set to 0 (default value), then 6lowpan is disabled.
 * Other values are used to indicate a Protocol Service Multiplexer
 * value for 6lowpan.
 */
static u16 psm_6lowpan;

/* We are listening incoming connections via this channel
 */
static struct l2cap_chan *listen_chan;

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struct lowpan_peer {
	struct list_head list;
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	struct l2cap_chan *chan;
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	/* peer addresses in various formats */
	unsigned char eui64_addr[EUI64_ADDR_LEN];
	struct in6_addr peer_addr;
};

struct lowpan_dev {
	struct list_head list;

	struct hci_dev *hdev;
	struct net_device *netdev;
	struct list_head peers;
	atomic_t peer_count; /* number of items in peers list */

	struct work_struct delete_netdev;
	struct delayed_work notify_peers;
};

static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)
{
	return netdev_priv(netdev);
}

static inline void peer_add(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_add(&peer->list, &dev->peers);
	atomic_inc(&dev->peer_count);
}

static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_del(&peer->list);

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	module_put(THIS_MODULE);

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	if (atomic_dec_and_test(&dev->peer_count)) {
		BT_DBG("last peer");
		return true;
	}

	return false;
}

static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
						 bdaddr_t *ba, __u8 type)
{
	struct lowpan_peer *peer, *tmp;

	BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
	       ba, type);

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
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		BT_DBG("dst addr %pMR dst type %d",
		       &peer->chan->dst, peer->chan->dst_type);
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		if (bacmp(&peer->chan->dst, ba))
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			continue;

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		if (type == peer->chan->dst_type)
			return peer;
	}

	return NULL;
}

static inline struct lowpan_peer *peer_lookup_chan(struct lowpan_dev *dev,
						   struct l2cap_chan *chan)
{
	struct lowpan_peer *peer, *tmp;

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
		if (peer->chan == chan)
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			return peer;
	}

	return NULL;
}

static inline struct lowpan_peer *peer_lookup_conn(struct lowpan_dev *dev,
						   struct l2cap_conn *conn)
{
	struct lowpan_peer *peer, *tmp;

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
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		if (peer->chan->conn == conn)
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			return peer;
	}

	return NULL;
}

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static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,
						  struct in6_addr *daddr,
						  struct sk_buff *skb)
{
	struct lowpan_peer *peer, *tmp;
	struct in6_addr *nexthop;
	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
	int count = atomic_read(&dev->peer_count);

	BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);

	/* If we have multiple 6lowpan peers, then check where we should
	 * send the packet. If only one peer exists, then we can send the
	 * packet right away.
	 */
	if (count == 1)
		return list_first_entry(&dev->peers, struct lowpan_peer,
					list);

	if (!rt) {
		nexthop = &lowpan_cb(skb)->gw;

		if (ipv6_addr_any(nexthop))
			return NULL;
	} else {
		nexthop = rt6_nexthop(rt);

		/* We need to remember the address because it is needed
		 * by bt_xmit() when sending the packet. In bt_xmit(), the
		 * destination routing info is not set.
		 */
		memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
	}

	BT_DBG("gw %pI6c", nexthop);

	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
		BT_DBG("dst addr %pMR dst type %d ip %pI6c",
		       &peer->chan->dst, peer->chan->dst_type,
		       &peer->peer_addr);

		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop))
			return peer;
	}

	return NULL;
}

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static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_peer *peer = NULL;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		peer = peer_lookup_conn(entry, conn);
		if (peer)
			break;
	}

	read_unlock_irqrestore(&devices_lock, flags);

	return peer;
}

static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_dev *dev = NULL;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		if (conn->hcon->hdev == entry->hdev) {
			dev = entry;
			break;
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);

	return dev;
}

static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
{
	struct sk_buff *skb_cp;
	int ret;

	skb_cp = skb_copy(skb, GFP_ATOMIC);
	if (!skb_cp)
		return -ENOMEM;

	ret = netif_rx(skb_cp);
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	if (ret < 0) {
		BT_DBG("receive skb %d", ret);
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		return NET_RX_DROP;
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	}
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	return ret;
}

static int process_data(struct sk_buff *skb, struct net_device *netdev,
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			struct l2cap_chan *chan)
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{
	const u8 *saddr, *daddr;
	u8 iphc0, iphc1;
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	unsigned long flags;

	dev = lowpan_dev(netdev);

	read_lock_irqsave(&devices_lock, flags);
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	peer = peer_lookup_chan(dev, chan);
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	read_unlock_irqrestore(&devices_lock, flags);
	if (!peer)
		goto drop;

	saddr = peer->eui64_addr;
	daddr = dev->netdev->dev_addr;

	/* at least two bytes will be used for the encoding */
	if (skb->len < 2)
		goto drop;

	if (lowpan_fetch_skb_u8(skb, &iphc0))
		goto drop;

	if (lowpan_fetch_skb_u8(skb, &iphc1))
		goto drop;

	return lowpan_process_data(skb, netdev,
				   saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
				   daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
				   iphc0, iphc1, give_skb_to_upper);

drop:
	kfree_skb(skb);
	return -EINVAL;
}

static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
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		    struct l2cap_chan *chan)
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{
	struct sk_buff *local_skb;
	int ret;

	if (!netif_running(dev))
		goto drop;

	if (dev->type != ARPHRD_6LOWPAN)
		goto drop;

	/* check that it's our buffer */
	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
		/* Copy the packet so that the IPv6 header is
		 * properly aligned.
		 */
		local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
					    skb_tailroom(skb), GFP_ATOMIC);
		if (!local_skb)
			goto drop;

		local_skb->protocol = htons(ETH_P_IPV6);
		local_skb->pkt_type = PACKET_HOST;

		skb_reset_network_header(local_skb);
		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));

		if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
			kfree_skb(local_skb);
			goto drop;
		}

		dev->stats.rx_bytes += skb->len;
		dev->stats.rx_packets++;

		kfree_skb(local_skb);
		kfree_skb(skb);
	} else {
		switch (skb->data[0] & 0xe0) {
		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
			local_skb = skb_clone(skb, GFP_ATOMIC);
			if (!local_skb)
				goto drop;

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			ret = process_data(local_skb, dev, chan);
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			if (ret != NET_RX_SUCCESS)
				goto drop;

			dev->stats.rx_bytes += skb->len;
			dev->stats.rx_packets++;

			kfree_skb(skb);
			break;
		default:
			break;
		}
	}

	return NET_RX_SUCCESS;

drop:
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	dev->stats.rx_dropped++;
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	kfree_skb(skb);
	return NET_RX_DROP;
}

/* Packet from BT LE device */
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static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
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{
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	int err;

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	peer = lookup_peer(chan->conn);
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	if (!peer)
		return -ENOENT;

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	dev = lookup_dev(chan->conn);
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	if (!dev || !dev->netdev)
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		return -ENOENT;

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	err = recv_pkt(skb, dev->netdev, chan);
	if (err) {
		BT_DBG("recv pkt %d", err);
		err = -EAGAIN;
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	}

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	return err;
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}

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static u8 get_addr_type_from_eui64(u8 byte)
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{
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	/* Is universal(0) or local(1) bit */
	return ((byte & 0x02) ? BDADDR_LE_RANDOM : BDADDR_LE_PUBLIC);
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}

static void copy_to_bdaddr(struct in6_addr *ip6_daddr, bdaddr_t *addr)
{
	u8 *eui64 = ip6_daddr->s6_addr + 8;
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	addr->b[0] = eui64[7];
	addr->b[1] = eui64[6];
	addr->b[2] = eui64[5];
	addr->b[3] = eui64[2];
	addr->b[4] = eui64[1];
	addr->b[5] = eui64[0];
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}
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static void convert_dest_bdaddr(struct in6_addr *ip6_daddr,
				bdaddr_t *addr, u8 *addr_type)
{
	copy_to_bdaddr(ip6_daddr, addr);
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	/* We need to toggle the U/L bit that we got from IPv6 address
	 * so that we get the proper address and type of the BD address.
	 */
	addr->b[5] ^= 0x02;

	*addr_type = get_addr_type_from_eui64(addr->b[5]);
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}

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static int setup_header(struct sk_buff *skb, struct net_device *netdev,
			bdaddr_t *peer_addr, u8 *peer_addr_type)
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{
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	struct in6_addr ipv6_daddr;
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	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	bdaddr_t addr, *any = BDADDR_ANY;
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	u8 *daddr = any->b;
	int err, status = 0;
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	dev = lowpan_dev(netdev);

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	memcpy(&ipv6_daddr, &lowpan_cb(skb)->addr, sizeof(ipv6_daddr));

	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
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		lowpan_cb(skb)->chan = NULL;
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	} else {
		unsigned long flags;
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		u8 addr_type;
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		/* Get destination BT device from skb.
		 * If there is no such peer then discard the packet.
		 */
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		convert_dest_bdaddr(&ipv6_daddr, &addr, &addr_type);
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		BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
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		       addr_type, &ipv6_daddr);
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		read_lock_irqsave(&devices_lock, flags);
		peer = peer_lookup_ba(dev, &addr, addr_type);
		read_unlock_irqrestore(&devices_lock, flags);

		if (!peer) {
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			/* The packet might be sent to 6lowpan interface
			 * because of routing (either via default route
			 * or user set route) so get peer according to
			 * the destination address.
			 */
			read_lock_irqsave(&devices_lock, flags);
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			peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
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			read_unlock_irqrestore(&devices_lock, flags);
			if (!peer) {
				BT_DBG("no such peer %pMR found", &addr);
				return -ENOENT;
			}
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		}

		daddr = peer->eui64_addr;
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		*peer_addr = addr;
		*peer_addr_type = addr_type;
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		lowpan_cb(skb)->chan = peer->chan;
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		status = 1;
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	}

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	lowpan_header_compress(skb, netdev, ETH_P_IPV6, daddr,
			       dev->netdev->dev_addr, skb->len);

	err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
	if (err < 0)
		return err;

	return status;
}

static int header_create(struct sk_buff *skb, struct net_device *netdev,
			 unsigned short type, const void *_daddr,
			 const void *_saddr, unsigned int len)
{
	struct ipv6hdr *hdr;

	if (type != ETH_P_IPV6)
		return -EINVAL;

	hdr = ipv6_hdr(skb);

	memcpy(&lowpan_cb(skb)->addr, &hdr->daddr, sizeof(struct in6_addr));
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	return 0;
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}

/* Packet to BT LE device */
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static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
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		    struct net_device *netdev, bool is_mcast)
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{
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	struct msghdr msg;
	struct kvec iv;
	int err;

	/* Remember the skb so that we can send EAGAIN to the caller if
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	 * we run out of credits. This is not done for multicast packets
	 * because we generate mcast packet in this module and are not
	 * really able to remember the skb after this packet is sent.
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	 */
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	if (is_mcast)
		chan->data = NULL;
	else
		chan->data = skb;
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	memset(&msg, 0, sizeof(msg));
	msg.msg_iov = (struct iovec *) &iv;
	msg.msg_iovlen = 1;
	iv.iov_base = skb->data;
	iv.iov_len = skb->len;

	err = l2cap_chan_send(chan, &msg, skb->len);
	if (err > 0) {
		netdev->stats.tx_bytes += err;
		netdev->stats.tx_packets++;
		return 0;
	}

	if (!err)
		err = lowpan_cb(skb)->status;

	if (err < 0) {
		if (err == -EAGAIN)
			netdev->stats.tx_dropped++;
		else
			netdev->stats.tx_errors++;
	}
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	return err;
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}

static void send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
{
	struct sk_buff *local_skb;
	struct lowpan_dev *entry, *tmp;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		struct lowpan_peer *pentry, *ptmp;
		struct lowpan_dev *dev;

		if (entry->netdev != netdev)
			continue;

		dev = lowpan_dev(entry->netdev);

		list_for_each_entry_safe(pentry, ptmp, &dev->peers, list) {
			local_skb = skb_clone(skb, GFP_ATOMIC);

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			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
			       netdev->name,
			       &pentry->chan->dst, pentry->chan->dst_type,
			       &pentry->peer_addr, pentry->chan);
			send_pkt(pentry->chan, local_skb, netdev, true);
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			kfree_skb(local_skb);
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);
}

static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	int err = 0;
	bdaddr_t addr;
	u8 addr_type;

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	/* We must take a copy of the skb before we modify/replace the ipv6
	 * header as the header could be used elsewhere
	 */
	skb = skb_unshare(skb, GFP_ATOMIC);
	if (!skb)
		return NET_XMIT_DROP;

	/* Return values from setup_header()
	 *  <0 - error, packet is dropped
	 *   0 - this is a multicast packet
	 *   1 - this is unicast packet
	 */
	err = setup_header(skb, netdev, &addr, &addr_type);
	if (err < 0) {
		kfree_skb(skb);
		return NET_XMIT_DROP;
	}
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	if (err) {
		if (lowpan_cb(skb)->chan) {
			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
			       netdev->name, &addr, addr_type,
			       &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
			err = send_pkt(lowpan_cb(skb)->chan, skb, netdev,
				       false);
		} else {
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			err = -ENOENT;
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		}
	} else {
		/* We need to send the packet to every device behind this
		 * interface.
		 */
		send_mcast_pkt(skb, netdev);
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	}

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	dev_kfree_skb(skb);

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	if (err)
		BT_DBG("ERROR: xmit failed (%d)", err);

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	return err < 0 ? NET_XMIT_DROP : err;
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}

static const struct net_device_ops netdev_ops = {
	.ndo_start_xmit		= bt_xmit,
};

static struct header_ops header_ops = {
	.create	= header_create,
};

static void netdev_setup(struct net_device *dev)
{
	dev->addr_len		= EUI64_ADDR_LEN;
	dev->type		= ARPHRD_6LOWPAN;

	dev->hard_header_len	= 0;
	dev->needed_tailroom	= 0;
	dev->mtu		= IPV6_MIN_MTU;
	dev->tx_queue_len	= 0;
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	dev->flags		= IFF_RUNNING | IFF_POINTOPOINT |
				  IFF_MULTICAST;
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	dev->watchdog_timeo	= 0;

	dev->netdev_ops		= &netdev_ops;
	dev->header_ops		= &header_ops;
	dev->destructor		= free_netdev;
}

static struct device_type bt_type = {
	.name	= "bluetooth",
};

static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
{
	/* addr is the BT address in little-endian format */
	eui[0] = addr[5];
	eui[1] = addr[4];
	eui[2] = addr[3];
	eui[3] = 0xFF;
	eui[4] = 0xFE;
	eui[5] = addr[2];
	eui[6] = addr[1];
	eui[7] = addr[0];

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	/* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
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	if (addr_type == BDADDR_LE_PUBLIC)
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		eui[0] &= ~0x02;
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	else
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		eui[0] |= 0x02;

	BT_DBG("type %d addr %*phC", addr_type, 8, eui);
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}

static void set_dev_addr(struct net_device *netdev, bdaddr_t *addr,
		         u8 addr_type)
{
	netdev->addr_assign_type = NET_ADDR_PERM;
	set_addr(netdev->dev_addr, addr->b, addr_type);
}

static void ifup(struct net_device *netdev)
{
	int err;

	rtnl_lock();
	err = dev_open(netdev);
	if (err < 0)
		BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
	rtnl_unlock();
}

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static void ifdown(struct net_device *netdev)
{
	int err;

	rtnl_lock();
	err = dev_close(netdev);
	if (err < 0)
		BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
	rtnl_unlock();
}

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static void do_notify_peers(struct work_struct *work)
{
	struct lowpan_dev *dev = container_of(work, struct lowpan_dev,
					      notify_peers.work);

	netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
}

static bool is_bt_6lowpan(struct hci_conn *hcon)
{
	if (hcon->type != LE_LINK)
		return false;

729 730 731 732
	if (!psm_6lowpan)
		return false;

	return true;
733 734
}

735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768
static struct l2cap_chan *chan_create(void)
{
	struct l2cap_chan *chan;

	chan = l2cap_chan_create();
	if (!chan)
		return NULL;

	l2cap_chan_set_defaults(chan);

	chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
	chan->mode = L2CAP_MODE_LE_FLOWCTL;
	chan->omtu = 65535;
	chan->imtu = chan->omtu;

	return chan;
}

static struct l2cap_chan *chan_open(struct l2cap_chan *pchan)
{
	struct l2cap_chan *chan;

	chan = chan_create();
	if (!chan)
		return NULL;

	chan->remote_mps = chan->omtu;
	chan->mps = chan->omtu;

	chan->state = BT_CONNECTED;

	return chan;
}

769 770 771 772 773 774 775 776
static void set_ip_addr_bits(u8 addr_type, u8 *addr)
{
	if (addr_type == BDADDR_LE_PUBLIC)
		*addr |= 0x02;
	else
		*addr &= ~0x02;
}

777 778
static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
					struct lowpan_dev *dev)
779 780 781 782 783 784
{
	struct lowpan_peer *peer;
	unsigned long flags;

	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
	if (!peer)
785
		return NULL;
786

787
	peer->chan = chan;
788 789 790 791 792
	memset(&peer->peer_addr, 0, sizeof(struct in6_addr));

	/* RFC 2464 ch. 5 */
	peer->peer_addr.s6_addr[0] = 0xFE;
	peer->peer_addr.s6_addr[1] = 0x80;
793 794
	set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
		 chan->dst_type);
795 796 797 798

	memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
	       EUI64_ADDR_LEN);

799 800 801 802 803
	/* IPv6 address needs to have the U/L bit set properly so toggle
	 * it back here.
	 */
	set_ip_addr_bits(chan->dst_type, (u8 *)&peer->peer_addr.s6_addr + 8);

804 805 806 807 808 809 810 811 812
	write_lock_irqsave(&devices_lock, flags);
	INIT_LIST_HEAD(&peer->list);
	peer_add(dev, peer);
	write_unlock_irqrestore(&devices_lock, flags);

	/* Notifying peers about us needs to be done without locks held */
	INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));

813
	return peer->chan;
814 815
}

816
static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
817 818 819 820 821
{
	struct net_device *netdev;
	int err = 0;
	unsigned long flags;

822
	netdev = alloc_netdev(sizeof(struct lowpan_dev), IFACE_NAME_TEMPLATE,
823
			      NET_NAME_UNKNOWN, netdev_setup);
824 825 826
	if (!netdev)
		return -ENOMEM;

827
	set_dev_addr(netdev, &chan->src, chan->src_type);
828 829

	netdev->netdev_ops = &netdev_ops;
830
	SET_NETDEV_DEV(netdev, &chan->conn->hcon->dev);
831 832 833 834 835 836 837 838 839
	SET_NETDEV_DEVTYPE(netdev, &bt_type);

	err = register_netdev(netdev);
	if (err < 0) {
		BT_INFO("register_netdev failed %d", err);
		free_netdev(netdev);
		goto out;
	}

840 841 842
	BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
	       netdev->ifindex, &chan->dst, chan->dst_type,
	       &chan->src, chan->src_type);
843 844
	set_bit(__LINK_STATE_PRESENT, &netdev->state);

845 846 847 848
	*dev = netdev_priv(netdev);
	(*dev)->netdev = netdev;
	(*dev)->hdev = chan->conn->hcon->hdev;
	INIT_LIST_HEAD(&(*dev)->peers);
849 850

	write_lock_irqsave(&devices_lock, flags);
851 852
	INIT_LIST_HEAD(&(*dev)->list);
	list_add(&(*dev)->list, &bt_6lowpan_devices);
853 854
	write_unlock_irqrestore(&devices_lock, flags);

855
	return 0;
856 857 858 859 860

out:
	return err;
}

861 862 863 864 865 866 867 868 869 870 871 872 873 874 875
static inline void chan_ready_cb(struct l2cap_chan *chan)
{
	struct lowpan_dev *dev;

	dev = lookup_dev(chan->conn);

	BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);

	if (!dev) {
		if (setup_netdev(chan, &dev) < 0) {
			l2cap_chan_del(chan, -ENOENT);
			return;
		}
	}

876 877 878
	if (!try_module_get(THIS_MODULE))
		return;

879 880 881 882
	add_peer_chan(chan, dev);
	ifup(dev->netdev);
}

883
static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
884
{
885
	struct l2cap_chan *chan;
886

887 888
	chan = chan_open(pchan);
	chan->ops = pchan->ops;
889 890 891

	BT_DBG("chan %p pchan %p", chan, pchan);

892
	return chan;
893 894
}

895 896 897 898 899 900 901 902 903 904
static void delete_netdev(struct work_struct *work)
{
	struct lowpan_dev *entry = container_of(work, struct lowpan_dev,
						delete_netdev);

	unregister_netdev(entry->netdev);

	/* The entry pointer is deleted in device_event() */
}

905
static void chan_close_cb(struct l2cap_chan *chan)
906 907 908 909 910 911
{
	struct lowpan_dev *entry, *tmp;
	struct lowpan_dev *dev = NULL;
	struct lowpan_peer *peer;
	int err = -ENOENT;
	unsigned long flags;
912
	bool last = false, removed = true;
913

914 915 916 917 918 919 920 921 922 923 924
	BT_DBG("chan %p conn %p", chan, chan->conn);

	if (chan->conn && chan->conn->hcon) {
		if (!is_bt_6lowpan(chan->conn->hcon))
			return;

		/* If conn is set, then the netdev is also there and we should
		 * not remove it.
		 */
		removed = false;
	}
925 926 927 928 929

	write_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		dev = lowpan_dev(entry->netdev);
930
		peer = peer_lookup_chan(dev, chan);
931 932 933
		if (peer) {
			last = peer_del(dev, peer);
			err = 0;
934 935 936 937 938 939 940 941

			BT_DBG("dev %p removing %speer %p", dev,
			       last ? "last " : "1 ", peer);
			BT_DBG("chan %p orig refcnt %d", chan,
			       atomic_read(&chan->kref.refcount));

			l2cap_chan_put(chan);
			kfree(peer);
942 943 944 945 946 947 948 949 950
			break;
		}
	}

	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
		write_unlock_irqrestore(&devices_lock, flags);

		cancel_delayed_work_sync(&dev->notify_peers);

951 952
		ifdown(dev->netdev);

953 954 955 956
		if (!removed) {
			INIT_WORK(&entry->delete_netdev, delete_netdev);
			schedule_work(&entry->delete_netdev);
		}
957 958 959 960
	} else {
		write_unlock_irqrestore(&devices_lock, flags);
	}

961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986
	return;
}

static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
{
	BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
	       state_to_string(state), err);
}

static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
					 unsigned long hdr_len,
					 unsigned long len, int nb)
{
	/* Note that we must allocate using GFP_ATOMIC here as
	 * this function is called originally from netdev hard xmit
	 * function in atomic context.
	 */
	return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
}

static void chan_suspend_cb(struct l2cap_chan *chan)
{
	struct sk_buff *skb = chan->data;

	BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);

987 988 989
	if (!skb)
		return;

990 991 992 993 994 995 996 997 998
	lowpan_cb(skb)->status = -EAGAIN;
}

static void chan_resume_cb(struct l2cap_chan *chan)
{
	struct sk_buff *skb = chan->data;

	BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);

999 1000 1001
	if (!skb)
		return;

1002 1003 1004 1005 1006
	lowpan_cb(skb)->status = 0;
}

static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
{
1007
	return L2CAP_CONN_TIMEOUT;
1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
}

static const struct l2cap_ops bt_6lowpan_chan_ops = {
	.name			= "L2CAP 6LoWPAN channel",
	.new_connection		= chan_new_conn_cb,
	.recv			= chan_recv_cb,
	.close			= chan_close_cb,
	.state_change		= chan_state_change_cb,
	.ready			= chan_ready_cb,
	.resume			= chan_resume_cb,
	.suspend		= chan_suspend_cb,
	.get_sndtimeo		= chan_get_sndtimeo_cb,
	.alloc_skb		= chan_alloc_skb_cb,
	.memcpy_fromiovec	= l2cap_chan_no_memcpy_fromiovec,

	.teardown		= l2cap_chan_no_teardown,
	.defer			= l2cap_chan_no_defer,
	.set_shutdown		= l2cap_chan_no_set_shutdown,
};

static inline __u8 bdaddr_type(__u8 type)
{
	if (type == ADDR_LE_DEV_PUBLIC)
		return BDADDR_LE_PUBLIC;
	else
		return BDADDR_LE_RANDOM;
}

static struct l2cap_chan *chan_get(void)
{
	struct l2cap_chan *pchan;

	pchan = chan_create();
	if (!pchan)
		return NULL;

	pchan->ops = &bt_6lowpan_chan_ops;

	return pchan;
}

static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
{
	struct l2cap_chan *pchan;
	int err;

	pchan = chan_get();
	if (!pchan)
		return -EINVAL;

	err = l2cap_chan_connect(pchan, cpu_to_le16(psm_6lowpan), 0,
				 addr, dst_type);

	BT_DBG("chan %p err %d", pchan, err);
	if (err < 0)
		l2cap_chan_put(pchan);

1065 1066 1067
	return err;
}

1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315
static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
{
	struct lowpan_peer *peer;

	BT_DBG("conn %p dst type %d", conn, dst_type);

	peer = lookup_peer(conn);
	if (!peer)
		return -ENOENT;

	BT_DBG("peer %p chan %p", peer, peer->chan);

	l2cap_chan_close(peer->chan, ENOENT);

	return 0;
}

static struct l2cap_chan *bt_6lowpan_listen(void)
{
	bdaddr_t *addr = BDADDR_ANY;
	struct l2cap_chan *pchan;
	int err;

	if (psm_6lowpan == 0)
		return NULL;

	pchan = chan_get();
	if (!pchan)
		return NULL;

	pchan->state = BT_LISTEN;
	pchan->src_type = BDADDR_LE_PUBLIC;

	BT_DBG("psm 0x%04x chan %p src type %d", psm_6lowpan, pchan,
	       pchan->src_type);

	err = l2cap_add_psm(pchan, addr, cpu_to_le16(psm_6lowpan));
	if (err) {
		l2cap_chan_put(pchan);
		BT_ERR("psm cannot be added err %d", err);
		return NULL;
	}

	return pchan;
}

static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
			  struct l2cap_conn **conn)
{
	struct hci_conn *hcon;
	struct hci_dev *hdev;
	bdaddr_t *src = BDADDR_ANY;
	int n;

	n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
		   &addr->b[5], &addr->b[4], &addr->b[3],
		   &addr->b[2], &addr->b[1], &addr->b[0],
		   addr_type);

	if (n < 7)
		return -EINVAL;

	hdev = hci_get_route(addr, src);
	if (!hdev)
		return -ENOENT;

	hci_dev_lock(hdev);
	hcon = hci_conn_hash_lookup_ba(hdev, LE_LINK, addr);
	hci_dev_unlock(hdev);

	if (!hcon)
		return -ENOENT;

	*conn = (struct l2cap_conn *)hcon->l2cap_data;

	BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);

	return 0;
}

static void disconnect_all_peers(void)
{
	struct lowpan_dev *entry, *tmp_dev;
	struct lowpan_peer *peer, *tmp_peer, *new_peer;
	struct list_head peers;
	unsigned long flags;

	INIT_LIST_HEAD(&peers);

	/* We make a separate list of peers as the close_cb() will
	 * modify the device peers list so it is better not to mess
	 * with the same list at the same time.
	 */

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp_dev, &bt_6lowpan_devices, list) {
		list_for_each_entry_safe(peer, tmp_peer, &entry->peers, list) {
			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
			if (!new_peer)
				break;

			new_peer->chan = peer->chan;
			INIT_LIST_HEAD(&new_peer->list);

			list_add(&new_peer->list, &peers);
		}
	}

	read_unlock_irqrestore(&devices_lock, flags);

	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
		l2cap_chan_close(peer->chan, ENOENT);
		kfree(peer);
	}
}

static int lowpan_psm_set(void *data, u64 val)
{
	u16 psm;

	psm = val;
	if (psm == 0 || psm_6lowpan != psm)
		/* Disconnect existing connections if 6lowpan is
		 * disabled (psm = 0), or if psm changes.
		 */
		disconnect_all_peers();

	psm_6lowpan = psm;

	if (listen_chan) {
		l2cap_chan_close(listen_chan, 0);
		l2cap_chan_put(listen_chan);
	}

	listen_chan = bt_6lowpan_listen();

	return 0;
}

static int lowpan_psm_get(void *data, u64 *val)
{
	*val = psm_6lowpan;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(lowpan_psm_fops, lowpan_psm_get,
			lowpan_psm_set, "%llu\n");

static ssize_t lowpan_control_write(struct file *fp,
				    const char __user *user_buffer,
				    size_t count,
				    loff_t *position)
{
	char buf[32];
	size_t buf_size = min(count, sizeof(buf) - 1);
	int ret;
	bdaddr_t addr;
	u8 addr_type;
	struct l2cap_conn *conn = NULL;

	if (copy_from_user(buf, user_buffer, buf_size))
		return -EFAULT;

	buf[buf_size] = '\0';

	if (memcmp(buf, "connect ", 8) == 0) {
		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
		if (ret == -EINVAL)
			return ret;

		if (listen_chan) {
			l2cap_chan_close(listen_chan, 0);
			l2cap_chan_put(listen_chan);
			listen_chan = NULL;
		}

		if (conn) {
			struct lowpan_peer *peer;

			if (!is_bt_6lowpan(conn->hcon))
				return -EINVAL;

			peer = lookup_peer(conn);
			if (peer) {
				BT_DBG("6LoWPAN connection already exists");
				return -EALREADY;
			}

			BT_DBG("conn %p dst %pMR type %d user %d", conn,
			       &conn->hcon->dst, conn->hcon->dst_type,
			       addr_type);
		}

		ret = bt_6lowpan_connect(&addr, addr_type);
		if (ret < 0)
			return ret;

		return count;
	}

	if (memcmp(buf, "disconnect ", 11) == 0) {
		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
		if (ret < 0)
			return ret;

		ret = bt_6lowpan_disconnect(conn, addr_type);
		if (ret < 0)
			return ret;

		return count;
	}

	return count;
}

static int lowpan_control_show(struct seq_file *f, void *ptr)
{
	struct lowpan_dev *entry, *tmp_dev;
	struct lowpan_peer *peer, *tmp_peer;
	unsigned long flags;

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp_dev, &bt_6lowpan_devices, list) {
		list_for_each_entry_safe(peer, tmp_peer, &entry->peers, list)
			seq_printf(f, "%pMR (type %u)\n",
				   &peer->chan->dst, peer->chan->dst_type);
	}

	read_unlock_irqrestore(&devices_lock, flags);

	return 0;
}

static int lowpan_control_open(struct inode *inode, struct file *file)
{
	return single_open(file, lowpan_control_show, inode->i_private);
}

static const struct file_operations lowpan_control_fops = {
	.open		= lowpan_control_open,
	.read		= seq_read,
	.write		= lowpan_control_write,
	.llseek		= seq_lseek,
	.release	= single_release,
};

1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
static void disconnect_devices(void)
{
	struct lowpan_dev *entry, *tmp, *new_dev;
	struct list_head devices;
	unsigned long flags;

	INIT_LIST_HEAD(&devices);

	/* We make a separate list of devices because the unregister_netdev()
	 * will call device_event() which will also want to modify the same
	 * devices list.
	 */

	read_lock_irqsave(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
		new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
		if (!new_dev)
			break;

		new_dev->netdev = entry->netdev;
		INIT_LIST_HEAD(&new_dev->list);

		list_add(&new_dev->list, &devices);
	}

	read_unlock_irqrestore(&devices_lock, flags);

	list_for_each_entry_safe(entry, tmp, &devices, list) {
		ifdown(entry->netdev);
		BT_DBG("Unregistering netdev %s %p",
		       entry->netdev->name, entry->netdev);
		unregister_netdev(entry->netdev);
		kfree(entry);
	}
}

1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368
static int device_event(struct notifier_block *unused,
			unsigned long event, void *ptr)
{
	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
	struct lowpan_dev *entry, *tmp;
	unsigned long flags;

	if (netdev->type != ARPHRD_6LOWPAN)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UNREGISTER:
		write_lock_irqsave(&devices_lock, flags);
		list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices,
					 list) {
			if (entry->netdev == netdev) {
1369 1370
				BT_DBG("Unregistered netdev %s %p",
				       netdev->name, netdev);
1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386
				list_del(&entry->list);
				kfree(entry);
				break;
			}
		}
		write_unlock_irqrestore(&devices_lock, flags);
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block bt_6lowpan_dev_notifier = {
	.notifier_call = device_event,
};

1387
static int __init bt_6lowpan_init(void)
1388
{
1389 1390 1391 1392 1393 1394 1395
	lowpan_psm_debugfs = debugfs_create_file("6lowpan_psm", 0644,
						 bt_debugfs, NULL,
						 &lowpan_psm_fops);
	lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
						     bt_debugfs, NULL,
						     &lowpan_control_fops);

1396 1397 1398
	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
}

1399
static void __exit bt_6lowpan_exit(void)
1400
{
1401 1402 1403 1404 1405 1406 1407 1408
	debugfs_remove(lowpan_psm_debugfs);
	debugfs_remove(lowpan_control_debugfs);

	if (listen_chan) {
		l2cap_chan_close(listen_chan, 0);
		l2cap_chan_put(listen_chan);
	}

1409 1410
	disconnect_devices();

1411 1412
	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
}
1413 1414 1415 1416 1417 1418 1419 1420

module_init(bt_6lowpan_init);
module_exit(bt_6lowpan_exit);

MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");