Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1283 insertions, 0 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
new file mode 100644
index 000000000..4eb1b3ced
--- /dev/null
+++ b/net/bluetooth/6lowpan.c
@@ -0,0 +1,1283 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+   Copyright (c) 2013-2014 Intel Corp.
+
+*/
+
+#include <linux/if_arp.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+#include <net/pkt_sched.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/l2cap.h>
+
+#include <net/6lowpan.h> /* for the compression support */
+
+#define VERSION "0.1"
+
+static struct dentry *lowpan_enable_debugfs;
+static struct dentry *lowpan_control_debugfs;
+
+#define IFACE_NAME_TEMPLATE "bt%d"
+
+struct skb_cb {
+	struct in6_addr addr;
+	struct in6_addr gw;
+	struct l2cap_chan *chan;
+};
+#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_SPINLOCK(devices_lock);
+
+static bool enable_6lowpan;
+
+/* We are listening incoming connections via this channel
+ */
+static struct l2cap_chan *listen_chan;
+static DEFINE_MUTEX(set_lock);
+
+struct lowpan_peer {
+	struct list_head list;
+	struct rcu_head rcu;
+	struct l2cap_chan *chan;
+
+	/* peer addresses in various formats */
+	unsigned char lladdr[ETH_ALEN];
+	struct in6_addr peer_addr;
+};
+
+struct lowpan_btle_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_btle_dev *
+lowpan_btle_dev(const struct net_device *netdev)
+{
+	return (struct lowpan_btle_dev *)lowpan_dev(netdev)->priv;
+}
+
+static inline void peer_add(struct lowpan_btle_dev *dev,
+			    struct lowpan_peer *peer)
+{
+	list_add_rcu(&peer->list, &dev->peers);
+	atomic_inc(&dev->peer_count);
+}
+
+static inline bool peer_del(struct lowpan_btle_dev *dev,
+			    struct lowpan_peer *peer)
+{
+	list_del_rcu(&peer->list);
+	kfree_rcu(peer, rcu);
+
+	module_put(THIS_MODULE);
+
+	if (atomic_dec_and_test(&dev->peer_count)) {
+		BT_DBG("last peer");
+		return true;
+	}
+
+	return false;
+}
+
+static inline struct lowpan_peer *
+__peer_lookup_chan(struct lowpan_btle_dev *dev, struct l2cap_chan *chan)
+{
+	struct lowpan_peer *peer;
+
+	list_for_each_entry_rcu(peer, &dev->peers, list) {
+		if (peer->chan == chan)
+			return peer;
+	}
+
+	return NULL;
+}
+
+static inline struct lowpan_peer *
+__peer_lookup_conn(struct lowpan_btle_dev *dev, struct l2cap_conn *conn)
+{
+	struct lowpan_peer *peer;
+
+	list_for_each_entry_rcu(peer, &dev->peers, list) {
+		if (peer->chan->conn == conn)
+			return peer;
+	}
+
+	return NULL;
+}
+
+static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_btle_dev *dev,
+						  struct in6_addr *daddr,
+						  struct sk_buff *skb)
+{
+	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
+	int count = atomic_read(&dev->peer_count);
+	const struct in6_addr *nexthop;
+	struct lowpan_peer *peer;
+	struct neighbour *neigh;
+
+	BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);
+
+	if (!rt) {
+		if (ipv6_addr_any(&lowpan_cb(skb)->gw)) {
+			/* There is neither route nor gateway,
+			 * probably the destination is a direct peer.
+			 */
+			nexthop = daddr;
+		} else {
+			/* There is a known gateway
+			 */
+			nexthop = &lowpan_cb(skb)->gw;
+		}
+	} else {
+		nexthop = rt6_nexthop(rt, daddr);
+
+		/* 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);
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(peer, &dev->peers, list) {
+		BT_DBG("dst addr %pMR dst type %u ip %pI6c",
+		       &peer->chan->dst, peer->chan->dst_type,
+		       &peer->peer_addr);
+
+		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
+			rcu_read_unlock();
+			return peer;
+		}
+	}
+
+	/* use the neighbour cache for matching addresses assigned by SLAAC */
+	neigh = __ipv6_neigh_lookup(dev->netdev, nexthop);
+	if (neigh) {
+		list_for_each_entry_rcu(peer, &dev->peers, list) {
+			if (!memcmp(neigh->ha, peer->lladdr, ETH_ALEN)) {
+				neigh_release(neigh);
+				rcu_read_unlock();
+				return peer;
+			}
+		}
+		neigh_release(neigh);
+	}
+
+	rcu_read_unlock();
+
+	return NULL;
+}
+
+static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
+{
+	struct lowpan_btle_dev *entry;
+	struct lowpan_peer *peer = NULL;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+		peer = __peer_lookup_conn(entry, conn);
+		if (peer)
+			break;
+	}
+
+	rcu_read_unlock();
+
+	return peer;
+}
+
+static struct lowpan_btle_dev *lookup_dev(struct l2cap_conn *conn)
+{
+	struct lowpan_btle_dev *entry;
+	struct lowpan_btle_dev *dev = NULL;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+		if (conn->hcon->hdev == entry->hdev) {
+			dev = entry;
+			break;
+		}
+	}
+
+	rcu_read_unlock();
+
+	return dev;
+}
+
+static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
+{
+	struct sk_buff *skb_cp;
+
+	skb_cp = skb_copy(skb, GFP_ATOMIC);
+	if (!skb_cp)
+		return NET_RX_DROP;
+
+	return netif_rx(skb_cp);
+}
+
+static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
+			   struct lowpan_peer *peer)
+{
+	const u8 *saddr;
+
+	saddr = peer->lladdr;
+
+	return lowpan_header_decompress(skb, netdev, netdev->dev_addr, saddr);
+}
+
+static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
+		    struct lowpan_peer *peer)
+{
+	struct sk_buff *local_skb;
+	int ret;
+
+	if (!netif_running(dev))
+		goto drop;
+
+	if (dev->type != ARPHRD_6LOWPAN || !skb->len)
+		goto drop;
+
+	skb_reset_network_header(skb);
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		goto drop;
+
+	/* check that it's our buffer */
+	if (lowpan_is_ipv6(*skb_network_header(skb))) {
+		/* Pull off the 1-byte of 6lowpan header. */
+		skb_pull(skb, 1);
+
+		/* 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;
+		local_skb->dev = dev;
+
+		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++;
+
+		consume_skb(local_skb);
+		consume_skb(skb);
+	} else if (lowpan_is_iphc(*skb_network_header(skb))) {
+		local_skb = skb_clone(skb, GFP_ATOMIC);
+		if (!local_skb)
+			goto drop;
+
+		local_skb->dev = dev;
+
+		ret = iphc_decompress(local_skb, dev, peer);
+		if (ret < 0) {
+			BT_DBG("iphc_decompress failed: %d", ret);
+			kfree_skb(local_skb);
+			goto drop;
+		}
+
+		local_skb->protocol = htons(ETH_P_IPV6);
+		local_skb->pkt_type = PACKET_HOST;
+
+		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++;
+
+		consume_skb(local_skb);
+		consume_skb(skb);
+	} else {
+		BT_DBG("unknown packet type");
+		goto drop;
+	}
+
+	return NET_RX_SUCCESS;
+
+drop:
+	dev->stats.rx_dropped++;
+	return NET_RX_DROP;
+}
+
+/* Packet from BT LE device */
+static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
+{
+	struct lowpan_btle_dev *dev;
+	struct lowpan_peer *peer;
+	int err;
+
+	peer = lookup_peer(chan->conn);
+	if (!peer)
+		return -ENOENT;
+
+	dev = lookup_dev(chan->conn);
+	if (!dev || !dev->netdev)
+		return -ENOENT;
+
+	err = recv_pkt(skb, dev->netdev, peer);
+	if (err) {
+		BT_DBG("recv pkt %d", err);
+		err = -EAGAIN;
+	}
+
+	return err;
+}
+
+static int setup_header(struct sk_buff *skb, struct net_device *netdev,
+			bdaddr_t *peer_addr, u8 *peer_addr_type)
+{
+	struct in6_addr ipv6_daddr;
+	struct ipv6hdr *hdr;
+	struct lowpan_btle_dev *dev;
+	struct lowpan_peer *peer;
+	u8 *daddr;
+	int err, status = 0;
+
+	hdr = ipv6_hdr(skb);
+
+	dev = lowpan_btle_dev(netdev);
+
+	memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr));
+
+	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
+		lowpan_cb(skb)->chan = NULL;
+		daddr = NULL;
+	} else {
+		BT_DBG("dest IP %pI6c", &ipv6_daddr);
+
+		/* 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.
+		 */
+		peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
+		if (!peer) {
+			BT_DBG("no such peer");
+			return -ENOENT;
+		}
+
+		daddr = peer->lladdr;
+		*peer_addr = peer->chan->dst;
+		*peer_addr_type = peer->chan->dst_type;
+		lowpan_cb(skb)->chan = peer->chan;
+
+		status = 1;
+	}
+
+	lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);
+
+	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)
+{
+	if (type != ETH_P_IPV6)
+		return -EINVAL;
+
+	return 0;
+}
+
+/* Packet to BT LE device */
+static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
+		    struct net_device *netdev)
+{
+	struct msghdr msg;
+	struct kvec iv;
+	int err;
+
+	/* Remember the skb so that we can send EAGAIN to the caller if
+	 * we run out of credits.
+	 */
+	chan->data = skb;
+
+	iv.iov_base = skb->data;
+	iv.iov_len = skb->len;
+
+	memset(&msg, 0, sizeof(msg));
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iv, 1, 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 < 0)
+		netdev->stats.tx_errors++;
+
+	return err;
+}
+
+static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
+{
+	struct sk_buff *local_skb;
+	struct lowpan_btle_dev *entry;
+	int err = 0;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+		struct lowpan_peer *pentry;
+		struct lowpan_btle_dev *dev;
+
+		if (entry->netdev != netdev)
+			continue;
+
+		dev = lowpan_btle_dev(entry->netdev);
+
+		list_for_each_entry_rcu(pentry, &dev->peers, list) {
+			int ret;
+
+			local_skb = skb_clone(skb, GFP_ATOMIC);
+
+			BT_DBG("xmit %s to %pMR type %u IP %pI6c chan %p",
+			       netdev->name,
+			       &pentry->chan->dst, pentry->chan->dst_type,
+			       &pentry->peer_addr, pentry->chan);
+			ret = send_pkt(pentry->chan, local_skb, netdev);
+			if (ret < 0)
+				err = ret;
+
+			kfree_skb(local_skb);
+		}
+	}
+
+	rcu_read_unlock();
+
+	return err;
+}
+
+static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	int err = 0;
+	bdaddr_t addr;
+	u8 addr_type;
+
+	/* 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;
+	}
+
+	if (err) {
+		if (lowpan_cb(skb)->chan) {
+			BT_DBG("xmit %s to %pMR type %u 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);
+		} else {
+			err = -ENOENT;
+		}
+	} else {
+		/* We need to send the packet to every device behind this
+		 * interface.
+		 */
+		err = send_mcast_pkt(skb, netdev);
+	}
+
+	dev_kfree_skb(skb);
+
+	if (err)
+		BT_DBG("ERROR: xmit failed (%d)", err);
+
+	return err < 0 ? NET_XMIT_DROP : err;
+}
+
+static int bt_dev_init(struct net_device *dev)
+{
+	netdev_lockdep_set_classes(dev);
+
+	return 0;
+}
+
+static const struct net_device_ops netdev_ops = {
+	.ndo_init		= bt_dev_init,
+	.ndo_start_xmit		= bt_xmit,
+};
+
+static const struct header_ops header_ops = {
+	.create	= header_create,
+};
+
+static void netdev_setup(struct net_device *dev)
+{
+	dev->hard_header_len	= 0;
+	dev->needed_tailroom	= 0;
+	dev->flags		= IFF_RUNNING | IFF_MULTICAST;
+	dev->watchdog_timeo	= 0;
+	dev->tx_queue_len	= DEFAULT_TX_QUEUE_LEN;
+
+	dev->netdev_ops		= &netdev_ops;
+	dev->header_ops		= &header_ops;
+	dev->needs_free_netdev	= true;
+}
+
+static struct device_type bt_type = {
+	.name	= "bluetooth",
+};
+
+static void ifup(struct net_device *netdev)
+{
+	int err;
+
+	rtnl_lock();
+	err = dev_open(netdev, NULL);
+	if (err < 0)
+		BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
+	rtnl_unlock();
+}
+
+static void ifdown(struct net_device *netdev)
+{
+	rtnl_lock();
+	dev_close(netdev);
+	rtnl_unlock();
+}
+
+static void do_notify_peers(struct work_struct *work)
+{
+	struct lowpan_btle_dev *dev = container_of(work, struct lowpan_btle_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;
+
+	if (!enable_6lowpan)
+		return false;
+
+	return true;
+}
+
+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->imtu = 1280;
+
+	return chan;
+}
+
+static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
+					struct lowpan_btle_dev *dev,
+					bool new_netdev)
+{
+	struct lowpan_peer *peer;
+
+	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
+	if (!peer)
+		return NULL;
+
+	peer->chan = chan;
+
+	baswap((void *)peer->lladdr, &chan->dst);
+
+	lowpan_iphc_uncompress_eui48_lladdr(&peer->peer_addr, peer->lladdr);
+
+	spin_lock(&devices_lock);
+	INIT_LIST_HEAD(&peer->list);
+	peer_add(dev, peer);
+	spin_unlock(&devices_lock);
+
+	/* Notifying peers about us needs to be done without locks held */
+	if (new_netdev)
+		INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
+	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
+
+	return peer->chan;
+}
+
+static int setup_netdev(struct l2cap_chan *chan, struct lowpan_btle_dev **dev)
+{
+	struct net_device *netdev;
+	bdaddr_t addr;
+	int err;
+
+	netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_btle_dev)),
+			      IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
+			      netdev_setup);
+	if (!netdev)
+		return -ENOMEM;
+
+	netdev->addr_assign_type = NET_ADDR_PERM;
+	baswap(&addr, &chan->src);
+	__dev_addr_set(netdev, &addr, sizeof(addr));
+
+	netdev->netdev_ops = &netdev_ops;
+	SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
+	SET_NETDEV_DEVTYPE(netdev, &bt_type);
+
+	*dev = lowpan_btle_dev(netdev);
+	(*dev)->netdev = netdev;
+	(*dev)->hdev = chan->conn->hcon->hdev;
+	INIT_LIST_HEAD(&(*dev)->peers);
+
+	spin_lock(&devices_lock);
+	INIT_LIST_HEAD(&(*dev)->list);
+	list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
+	spin_unlock(&devices_lock);
+
+	err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
+	if (err < 0) {
+		BT_INFO("register_netdev failed %d", err);
+		spin_lock(&devices_lock);
+		list_del_rcu(&(*dev)->list);
+		spin_unlock(&devices_lock);
+		free_netdev(netdev);
+		goto out;
+	}
+
+	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);
+	set_bit(__LINK_STATE_PRESENT, &netdev->state);
+
+	return 0;
+
+out:
+	return err;
+}
+
+static inline void chan_ready_cb(struct l2cap_chan *chan)
+{
+	struct lowpan_btle_dev *dev;
+	bool new_netdev = false;
+
+	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;
+		}
+		new_netdev = true;
+	}
+
+	if (!try_module_get(THIS_MODULE))
+		return;
+
+	add_peer_chan(chan, dev, new_netdev);
+	ifup(dev->netdev);
+}
+
+static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
+{
+	struct l2cap_chan *chan;
+
+	chan = chan_create();
+	if (!chan)
+		return NULL;
+
+	chan->ops = pchan->ops;
+
+	BT_DBG("chan %p pchan %p", chan, pchan);
+
+	return chan;
+}
+
+static void delete_netdev(struct work_struct *work)
+{
+	struct lowpan_btle_dev *entry = container_of(work,
+						     struct lowpan_btle_dev,
+						     delete_netdev);
+
+	lowpan_unregister_netdev(entry->netdev);
+
+	/* The entry pointer is deleted by the netdev destructor. */
+}
+
+static void chan_close_cb(struct l2cap_chan *chan)
+{
+	struct lowpan_btle_dev *entry;
+	struct lowpan_btle_dev *dev = NULL;
+	struct lowpan_peer *peer;
+	int err = -ENOENT;
+	bool last = false, remove = true;
+
+	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.
+		 */
+		remove = false;
+	}
+
+	spin_lock(&devices_lock);
+
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+		dev = lowpan_btle_dev(entry->netdev);
+		peer = __peer_lookup_chan(dev, chan);
+		if (peer) {
+			last = peer_del(dev, peer);
+			err = 0;
+
+			BT_DBG("dev %p removing %speer %p", dev,
+			       last ? "last " : "1 ", peer);
+			BT_DBG("chan %p orig refcnt %u", chan,
+			       kref_read(&chan->kref));
+
+			l2cap_chan_put(chan);
+			break;
+		}
+	}
+
+	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
+		spin_unlock(&devices_lock);
+
+		cancel_delayed_work_sync(&dev->notify_peers);
+
+		ifdown(dev->netdev);
+
+		if (remove) {
+			INIT_WORK(&entry->delete_netdev, delete_netdev);
+			schedule_work(&entry->delete_netdev);
+		}
+	} else {
+		spin_unlock(&devices_lock);
+	}
+}
+
+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 lowpan_btle_dev *dev;
+
+	BT_DBG("chan %p suspend", chan);
+
+	dev = lookup_dev(chan->conn);
+	if (!dev || !dev->netdev)
+		return;
+
+	netif_stop_queue(dev->netdev);
+}
+
+static void chan_resume_cb(struct l2cap_chan *chan)
+{
+	struct lowpan_btle_dev *dev;
+
+	BT_DBG("chan %p resume", chan);
+
+	dev = lookup_dev(chan->conn);
+	if (!dev || !dev->netdev)
+		return;
+
+	netif_wake_queue(dev->netdev);
+}
+
+static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
+{
+	return L2CAP_CONN_TIMEOUT;
+}
+
+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,
+
+	.teardown		= l2cap_chan_no_teardown,
+	.defer			= l2cap_chan_no_defer,
+	.set_shutdown		= l2cap_chan_no_set_shutdown,
+};
+
+static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
+{
+	struct l2cap_chan *chan;
+	int err;
+
+	chan = chan_create();
+	if (!chan)
+		return -EINVAL;
+
+	chan->ops = &bt_6lowpan_chan_ops;
+
+	err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
+				 addr, dst_type);
+
+	BT_DBG("chan %p err %d", chan, err);
+	if (err < 0)
+		l2cap_chan_put(chan);
+
+	return err;
+}
+
+static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
+{
+	struct lowpan_peer *peer;
+
+	BT_DBG("conn %p dst type %u", 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 *chan;
+	int err;
+
+	if (!enable_6lowpan)
+		return NULL;
+
+	chan = chan_create();
+	if (!chan)
+		return NULL;
+
+	chan->ops = &bt_6lowpan_chan_ops;
+	chan->state = BT_LISTEN;
+	chan->src_type = BDADDR_LE_PUBLIC;
+
+	atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);
+
+	BT_DBG("chan %p src type %u", chan, chan->src_type);
+
+	err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
+	if (err) {
+		l2cap_chan_put(chan);
+		BT_ERR("psm cannot be added err %d", err);
+		return NULL;
+	}
+
+	return chan;
+}
+
+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;
+	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;
+
+	/* The LE_PUBLIC address type is ignored because of BDADDR_ANY */
+	hdev = hci_get_route(addr, BDADDR_ANY, BDADDR_LE_PUBLIC);
+	if (!hdev)
+		return -ENOENT;
+
+	hci_dev_lock(hdev);
+	hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
+	hci_dev_unlock(hdev);
+	hci_dev_put(hdev);
+
+	if (!hcon)
+		return -ENOENT;
+
+	*conn = (struct l2cap_conn *)hcon->l2cap_data;
+
+	BT_DBG("conn %p dst %pMR type %u", *conn, &hcon->dst, hcon->dst_type);
+
+	return 0;
+}
+
+static void disconnect_all_peers(void)
+{
+	struct lowpan_btle_dev *entry;
+	struct lowpan_peer *peer, *tmp_peer, *new_peer;
+	struct list_head peers;
+
+	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.
+	 */
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
+		list_for_each_entry_rcu(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);
+		}
+	}
+
+	rcu_read_unlock();
+
+	spin_lock(&devices_lock);
+	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
+		l2cap_chan_close(peer->chan, ENOENT);
+
+		list_del_rcu(&peer->list);
+		kfree_rcu(peer, rcu);
+	}
+	spin_unlock(&devices_lock);
+}
+
+struct set_enable {
+	struct work_struct work;
+	bool flag;
+};
+
+static void do_enable_set(struct work_struct *work)
+{
+	struct set_enable *set_enable = container_of(work,
+						     struct set_enable, work);
+
+	if (!set_enable->flag || enable_6lowpan != set_enable->flag)
+		/* Disconnect existing connections if 6lowpan is
+		 * disabled
+		 */
+		disconnect_all_peers();
+
+	enable_6lowpan = set_enable->flag;
+
+	mutex_lock(&set_lock);
+	if (listen_chan) {
+		l2cap_chan_close(listen_chan, 0);
+		l2cap_chan_put(listen_chan);
+	}
+
+	listen_chan = bt_6lowpan_listen();
+	mutex_unlock(&set_lock);
+
+	kfree(set_enable);
+}
+
+static int lowpan_enable_set(void *data, u64 val)
+{
+	struct set_enable *set_enable;
+
+	set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
+	if (!set_enable)
+		return -ENOMEM;
+
+	set_enable->flag = !!val;
+	INIT_WORK(&set_enable->work, do_enable_set);
+
+	schedule_work(&set_enable->work);
+
+	return 0;
+}
+
+static int lowpan_enable_get(void *data, u64 *val)
+{
+	*val = enable_6lowpan;
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
+			 lowpan_enable_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;
+
+		mutex_lock(&set_lock);
+		if (listen_chan) {
+			l2cap_chan_close(listen_chan, 0);
+			l2cap_chan_put(listen_chan);
+			listen_chan = NULL;
+		}
+		mutex_unlock(&set_lock);
+
+		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 %u", 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_btle_dev *entry;
+	struct lowpan_peer *peer;
+
+	spin_lock(&devices_lock);
+
+	list_for_each_entry(entry, &bt_6lowpan_devices, list) {
+		list_for_each_entry(peer, &entry->peers, list)
+			seq_printf(f, "%pMR (type %u)\n",
+				   &peer->chan->dst, peer->chan->dst_type);
+	}
+
+	spin_unlock(&devices_lock);
+
+	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,
+};
+
+static void disconnect_devices(void)
+{
+	struct lowpan_btle_dev *entry, *tmp, *new_dev;
+	struct list_head devices;
+
+	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.
+	 */
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &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_rcu(&new_dev->list, &devices);
+	}
+
+	rcu_read_unlock();
+
+	list_for_each_entry_safe(entry, tmp, &devices, list) {
+		ifdown(entry->netdev);
+		BT_DBG("Unregistering netdev %s %p",
+		       entry->netdev->name, entry->netdev);
+		lowpan_unregister_netdev(entry->netdev);
+		kfree(entry);
+	}
+}
+
+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_btle_dev *entry;
+
+	if (netdev->type != ARPHRD_6LOWPAN)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case NETDEV_UNREGISTER:
+		spin_lock(&devices_lock);
+		list_for_each_entry(entry, &bt_6lowpan_devices, list) {
+			if (entry->netdev == netdev) {
+				BT_DBG("Unregistered netdev %s %p",
+				       netdev->name, netdev);
+				list_del(&entry->list);
+				break;
+			}
+		}
+		spin_unlock(&devices_lock);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block bt_6lowpan_dev_notifier = {
+	.notifier_call = device_event,
+};
+
+static int __init bt_6lowpan_init(void)
+{
+	lowpan_enable_debugfs = debugfs_create_file_unsafe("6lowpan_enable",
+							   0644, bt_debugfs,
+							   NULL,
+							   &lowpan_enable_fops);
+	lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
+						     bt_debugfs, NULL,
+						     &lowpan_control_fops);
+
+	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
+}
+
+static void __exit bt_6lowpan_exit(void)
+{
+	debugfs_remove(lowpan_enable_debugfs);
+	debugfs_remove(lowpan_control_debugfs);
+
+	if (listen_chan) {
+		l2cap_chan_close(listen_chan, 0);
+		l2cap_chan_put(listen_chan);
+	}
+
+	disconnect_devices();
+
+	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
+}
+
+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");