Bluetooth: 6LoWPAN: Use connected oriented channel instead of fixed one

Create a CoC dynamically instead of one fixed channel for communication
to peer devices.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

5 files changed, 588 insertions, 314 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 8796ffa08b43..bdb01eb3bfcc 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2013 Intel Corp.
+   Copyright (c) 2013-2014 Intel Corp.
 
    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
@@ -14,6 +14,7 @@
 #include <linux/if_arp.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
+#include <linux/debugfs.h>
 
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
@@ -25,16 +26,20 @@
 #include <net/bluetooth/hci_core.h>
 #include <net/bluetooth/l2cap.h>
 
-#include "6lowpan.h"
-
 #include <net/6lowpan.h> /* for the compression support */
 
+#define VERSION "0.1"
+
+static struct dentry *lowpan_psm_debugfs;
+static struct dentry *lowpan_control_debugfs;
+
 #define IFACE_NAME_TEMPLATE "bt%d"
 #define EUI64_ADDR_LEN 8
 
 struct skb_cb {
 	struct in6_addr addr;
-	struct l2cap_conn *conn;
+	struct l2cap_chan *chan;
+	int status;
 };
 #define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
 
@@ -48,9 +53,19 @@ struct skb_cb {
 static LIST_HEAD(bt_6lowpan_devices);
 static DEFINE_RWLOCK(devices_lock);
 
+/* 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;
+
 struct lowpan_peer {
 	struct list_head list;
-	struct l2cap_conn *conn;
+	struct l2cap_chan *chan;
 
 	/* peer addresses in various formats */
 	unsigned char eui64_addr[EUI64_ADDR_LEN];
@@ -101,13 +116,26 @@ static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
 	       ba, type);
 
 	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
-		BT_DBG("addr %pMR type %d",
-		       &peer->conn->hcon->dst, peer->conn->hcon->dst_type);
+		BT_DBG("dst addr %pMR dst type %d",
+		       &peer->chan->dst, peer->chan->dst_type);
 
-		if (bacmp(&peer->conn->hcon->dst, ba))
+		if (bacmp(&peer->chan->dst, ba))
 			continue;
 
-		if (type == peer->conn->hcon->dst_type)
+		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)
 			return peer;
 	}
 
@@ -120,7 +148,7 @@ static inline struct lowpan_peer *peer_lookup_conn(struct lowpan_dev *dev,
 	struct lowpan_peer *peer, *tmp;
 
 	list_for_each_entry_safe(peer, tmp, &dev->peers, list) {
-		if (peer->conn == conn)
+		if (peer->chan->conn == conn)
 			return peer;
 	}
 
@@ -176,16 +204,16 @@ static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
 		return -ENOMEM;
 
 	ret = netif_rx(skb_cp);
-
-	BT_DBG("receive skb %d", ret);
-	if (ret < 0)
+	if (ret < 0) {
+		BT_DBG("receive skb %d", ret);
 		return NET_RX_DROP;
+	}
 
 	return ret;
 }
 
 static int process_data(struct sk_buff *skb, struct net_device *netdev,
-			struct l2cap_conn *conn)
+			struct l2cap_chan *chan)
 {
 	const u8 *saddr, *daddr;
 	u8 iphc0, iphc1;
@@ -196,7 +224,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
 	dev = lowpan_dev(netdev);
 
 	read_lock_irqsave(&devices_lock, flags);
-	peer = peer_lookup_conn(dev, conn);
+	peer = peer_lookup_chan(dev, chan);
 	read_unlock_irqrestore(&devices_lock, flags);
 	if (!peer)
 		goto drop;
@@ -225,7 +253,7 @@ drop:
 }
 
 static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
-		    struct l2cap_conn *conn)
+		    struct l2cap_chan *chan)
 {
 	struct sk_buff *local_skb;
 	int ret;
@@ -269,7 +297,7 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 			if (!local_skb)
 				goto drop;
 
-			ret = process_data(local_skb, dev, conn);
+			ret = process_data(local_skb, dev, chan);
 			if (ret != NET_RX_SUCCESS)
 				goto drop;
 
@@ -286,147 +314,39 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 	return NET_RX_SUCCESS;
 
 drop:
+	dev->stats.rx_dropped++;
 	kfree_skb(skb);
 	return NET_RX_DROP;
 }
 
 /* Packet from BT LE device */
-int bt_6lowpan_recv(struct l2cap_conn *conn, struct sk_buff *skb)
+static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
 {
 	struct lowpan_dev *dev;
 	struct lowpan_peer *peer;
 	int err;
 
-	peer = lookup_peer(conn);
+	peer = lookup_peer(chan->conn);
 	if (!peer)
 		return -ENOENT;
 
-	dev = lookup_dev(conn);
+	dev = lookup_dev(chan->conn);
 	if (!dev || !dev->netdev)
 		return -ENOENT;
 
-	err = recv_pkt(skb, dev->netdev, conn);
-	BT_DBG("recv pkt %d", err);
-
-	return err;
-}
-
-static inline int skbuff_copy(void *msg, int len, int count, int mtu,
-			      struct sk_buff *skb, struct net_device *dev)
-{
-	struct sk_buff **frag;
-	int sent = 0;
-
-	memcpy(skb_put(skb, count), msg, count);
-
-	sent += count;
-	msg  += count;
-	len  -= count;
-
-	dev->stats.tx_bytes += count;
-	dev->stats.tx_packets++;
-
-	raw_dump_table(__func__, "Sending", skb->data, skb->len);
-
-	/* Continuation fragments (no L2CAP header) */
-	frag = &skb_shinfo(skb)->frag_list;
-	while (len > 0) {
-		struct sk_buff *tmp;
-
-		count = min_t(unsigned int, mtu, len);
-
-		tmp = bt_skb_alloc(count, GFP_ATOMIC);
-		if (!tmp)
-			return -ENOMEM;
-
-		*frag = tmp;
-
-		memcpy(skb_put(*frag, count), msg, count);
-
-		raw_dump_table(__func__, "Sending fragment",
-			       (*frag)->data, count);
-
-		(*frag)->priority = skb->priority;
-
-		sent += count;
-		msg  += count;
-		len  -= count;
-
-		skb->len += (*frag)->len;
-		skb->data_len += (*frag)->len;
-
-		frag = &(*frag)->next;
-
-		dev->stats.tx_bytes += count;
-		dev->stats.tx_packets++;
-	}
-
-	return sent;
-}
-
-static struct sk_buff *create_pdu(struct l2cap_conn *conn, void *msg,
-				  size_t len, u32 priority,
-				  struct net_device *dev)
-{
-	struct sk_buff *skb;
-	int err, count;
-	struct l2cap_hdr *lh;
-
-	/* FIXME: This mtu check should be not needed and atm is only used for
-	 * testing purposes
-	 */
-	if (conn->mtu > (L2CAP_LE_MIN_MTU + L2CAP_HDR_SIZE))
-		conn->mtu = L2CAP_LE_MIN_MTU + L2CAP_HDR_SIZE;
-
-	count = min_t(unsigned int, (conn->mtu - L2CAP_HDR_SIZE), len);
-
-	BT_DBG("conn %p len %zu mtu %d count %d", conn, len, conn->mtu, count);
-
-	skb = bt_skb_alloc(count + L2CAP_HDR_SIZE, GFP_ATOMIC);
-	if (!skb)
-		return ERR_PTR(-ENOMEM);
-
-	skb->priority = priority;
-
-	lh = (struct l2cap_hdr *)skb_put(skb, L2CAP_HDR_SIZE);
-	lh->cid = cpu_to_le16(L2CAP_FC_6LOWPAN);
-	lh->len = cpu_to_le16(len);
-
-	err = skbuff_copy(msg, len, count, conn->mtu, skb, dev);
-	if (unlikely(err < 0)) {
-		kfree_skb(skb);
-		BT_DBG("skbuff copy %d failed", err);
-		return ERR_PTR(err);
+	err = recv_pkt(skb, dev->netdev, chan);
+	if (err) {
+		BT_DBG("recv pkt %d", err);
+		err = -EAGAIN;
 	}
 
-	return skb;
-}
-
-static int conn_send(struct l2cap_conn *conn,
-		     void *msg, size_t len, u32 priority,
-		     struct net_device *dev)
-{
-	struct sk_buff *skb;
-
-	skb = create_pdu(conn, msg, len, priority, dev);
-	if (IS_ERR(skb))
-		return -EINVAL;
-
-	BT_DBG("conn %p skb %p len %d priority %u", conn, skb, skb->len,
-	       skb->priority);
-
-	hci_send_acl(conn->hchan, skb, ACL_START);
-
-	return 0;
+	return err;
 }
 
 static u8 get_addr_type_from_eui64(u8 byte)
 {
-	/* Is universal(0) or local(1) bit,  */
-	if (byte & 0x02)
-		return ADDR_LE_DEV_RANDOM;
-
-	return ADDR_LE_DEV_PUBLIC;
+	/* Is universal(0) or local(1) bit */
+	return ((byte & 0x02) ? BDADDR_LE_RANDOM : BDADDR_LE_PUBLIC);
 }
 
 static void copy_to_bdaddr(struct in6_addr *ip6_daddr, bdaddr_t *addr)
@@ -475,7 +395,7 @@ static int header_create(struct sk_buff *skb, struct net_device *netdev,
 	if (ipv6_addr_is_multicast(&hdr->daddr)) {
 		memcpy(&lowpan_cb(skb)->addr, &hdr->daddr,
 		       sizeof(struct in6_addr));
-		lowpan_cb(skb)->conn = NULL;
+		lowpan_cb(skb)->chan = NULL;
 	} else {
 		unsigned long flags;
 
@@ -484,9 +404,8 @@ static int header_create(struct sk_buff *skb, struct net_device *netdev,
 		 */
 		convert_dest_bdaddr(&hdr->daddr, &addr, &addr_type);
 
-		BT_DBG("dest addr %pMR type %s IP %pI6c", &addr,
-		       addr_type == ADDR_LE_DEV_PUBLIC ? "PUBLIC" : "RANDOM",
-		       &hdr->daddr);
+		BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
+		       addr_type, &hdr->daddr);
 
 		read_lock_irqsave(&devices_lock, flags);
 		peer = peer_lookup_ba(dev, &addr, addr_type);
@@ -501,7 +420,7 @@ static int header_create(struct sk_buff *skb, struct net_device *netdev,
 
 		memcpy(&lowpan_cb(skb)->addr, &hdr->daddr,
 		       sizeof(struct in6_addr));
-		lowpan_cb(skb)->conn = peer->conn;
+		lowpan_cb(skb)->chan = peer->chan;
 	}
 
 	saddr = dev->netdev->dev_addr;
@@ -510,14 +429,42 @@ static int header_create(struct sk_buff *skb, struct net_device *netdev,
 }
 
 /* Packet to BT LE device */
-static int send_pkt(struct l2cap_conn *conn, const void *saddr,
-		    const void *daddr, struct sk_buff *skb,
+static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
 		    struct net_device *netdev)
 {
-	raw_dump_table(__func__, "raw skb data dump before fragmentation",
-		       skb->data, skb->len);
+	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;
+
+	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++;
+	}
 
-	return conn_send(conn, skb->data, skb->len, 0, netdev);
+	return err;
 }
 
 static void send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
@@ -540,8 +487,7 @@ static void send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 		list_for_each_entry_safe(pentry, ptmp, &dev->peers, list) {
 			local_skb = skb_clone(skb, GFP_ATOMIC);
 
-			send_pkt(pentry->conn, netdev->dev_addr,
-				 pentry->eui64_addr, local_skb, netdev);
+			send_pkt(pentry->chan, local_skb, netdev);
 
 			kfree_skb(local_skb);
 		}
@@ -553,7 +499,6 @@ static void send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	int err = 0;
-	unsigned char *eui64_addr;
 	struct lowpan_dev *dev;
 	struct lowpan_peer *peer;
 	bdaddr_t addr;
@@ -568,21 +513,20 @@ static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
 		unsigned long flags;
 
 		convert_dest_bdaddr(&lowpan_cb(skb)->addr, &addr, &addr_type);
-		eui64_addr = lowpan_cb(skb)->addr.s6_addr + 8;
 		dev = lowpan_dev(netdev);
 
 		read_lock_irqsave(&devices_lock, flags);
 		peer = peer_lookup_ba(dev, &addr, addr_type);
 		read_unlock_irqrestore(&devices_lock, flags);
 
-		BT_DBG("xmit %s to %pMR type %s IP %pI6c peer %p",
-		       netdev->name, &addr,
-		       addr_type == ADDR_LE_DEV_PUBLIC ? "PUBLIC" : "RANDOM",
+		BT_DBG("xmit %s to %pMR type %d IP %pI6c peer %p",
+		       netdev->name, &addr, addr_type,
 		       &lowpan_cb(skb)->addr, peer);
 
-		if (peer && peer->conn)
-			err = send_pkt(peer->conn, netdev->dev_addr,
-				       eui64_addr, skb, netdev);
+		if (peer && peer->chan)
+			err = send_pkt(peer->chan, skb, netdev);
+		else
+			err = -ENOENT;
 	}
 	dev_kfree_skb(skb);
 
@@ -634,7 +578,7 @@ static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
 	eui[7] = addr[0];
 
 	/* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
-	if (addr_type == ADDR_LE_DEV_PUBLIC)
+	if (addr_type == BDADDR_LE_PUBLIC)
 		eui[0] &= ~0x02;
 	else
 		eui[0] |= 0x02;
@@ -673,26 +617,64 @@ static bool is_bt_6lowpan(struct hci_conn *hcon)
 	if (hcon->type != LE_LINK)
 		return false;
 
-	return test_bit(HCI_CONN_6LOWPAN, &hcon->flags);
+	if (!psm_6lowpan)
+		return false;
+
+	return true;
 }
 
-static int add_peer_conn(struct l2cap_conn *conn, struct lowpan_dev *dev)
+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;
+}
+
+static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
+					struct lowpan_dev *dev)
 {
 	struct lowpan_peer *peer;
 	unsigned long flags;
 
 	peer = kzalloc(sizeof(*peer), GFP_ATOMIC);
 	if (!peer)
-		return -ENOMEM;
+		return NULL;
 
-	peer->conn = conn;
+	peer->chan = chan;
 	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;
-	set_addr((u8 *)&peer->peer_addr.s6_addr + 8, conn->hcon->dst.b,
-	         conn->hcon->dst_type);
+	set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
+		 chan->dst_type);
 
 	memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
 	       EUI64_ADDR_LEN);
@@ -706,40 +688,24 @@ static int add_peer_conn(struct l2cap_conn *conn, struct lowpan_dev *dev)
 	INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
 	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));
 
-	return 0;
+	return peer->chan;
 }
 
-/* This gets called when BT LE 6LoWPAN device is connected. We then
- * create network device that acts as a proxy between BT LE device
- * and kernel network stack.
- */
-int bt_6lowpan_add_conn(struct l2cap_conn *conn)
+static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
 {
-	struct lowpan_peer *peer = NULL;
-	struct lowpan_dev *dev;
 	struct net_device *netdev;
 	int err = 0;
 	unsigned long flags;
 
-	if (!is_bt_6lowpan(conn->hcon))
-		return 0;
-
-	peer = lookup_peer(conn);
-	if (peer)
-		return -EEXIST;
-
-	dev = lookup_dev(conn);
-	if (dev)
-		return add_peer_conn(conn, dev);
-
-	netdev = alloc_netdev(sizeof(*dev), IFACE_NAME_TEMPLATE, netdev_setup);
+	netdev = alloc_netdev(sizeof(struct lowpan_dev), IFACE_NAME_TEMPLATE,
+			      netdev_setup);
 	if (!netdev)
 		return -ENOMEM;
 
-	set_dev_addr(netdev, &conn->hcon->src, conn->hcon->src_type);
+	set_dev_addr(netdev, &chan->src, chan->src_type);
 
 	netdev->netdev_ops = &netdev_ops;
-	SET_NETDEV_DEV(netdev, &conn->hcon->dev);
+	SET_NETDEV_DEV(netdev, &chan->conn->hcon->dev);
 	SET_NETDEV_DEVTYPE(netdev, &bt_type);
 
 	err = register_netdev(netdev);
@@ -749,28 +715,58 @@ int bt_6lowpan_add_conn(struct l2cap_conn *conn)
 		goto out;
 	}
 
-	BT_DBG("ifindex %d peer bdaddr %pMR my addr %pMR",
-	       netdev->ifindex, &conn->hcon->dst, &conn->hcon->src);
+	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);
 
-	dev = netdev_priv(netdev);
-	dev->netdev = netdev;
-	dev->hdev = conn->hcon->hdev;
-	INIT_LIST_HEAD(&dev->peers);
+	*dev = netdev_priv(netdev);
+	(*dev)->netdev = netdev;
+	(*dev)->hdev = chan->conn->hcon->hdev;
+	INIT_LIST_HEAD(&(*dev)->peers);
 
 	write_lock_irqsave(&devices_lock, flags);
-	INIT_LIST_HEAD(&dev->list);
-	list_add(&dev->list, &bt_6lowpan_devices);
+	INIT_LIST_HEAD(&(*dev)->list);
+	list_add(&(*dev)->list, &bt_6lowpan_devices);
 	write_unlock_irqrestore(&devices_lock, flags);
 
-	ifup(netdev);
-
-	return add_peer_conn(conn, dev);
+	return 0;
 
 out:
 	return err;
 }
 
+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;
+		}
+	}
+
+	add_peer_chan(chan, dev);
+	ifup(dev->netdev);
+}
+
+static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *chan)
+{
+	struct l2cap_chan *pchan;
+
+	pchan = chan_open(chan);
+	pchan->ops = chan->ops;
+
+	BT_DBG("chan %p pchan %p", chan, pchan);
+
+	return pchan;
+}
+
 static void delete_netdev(struct work_struct *work)
 {
 	struct lowpan_dev *entry = container_of(work, struct lowpan_dev,
@@ -781,26 +777,43 @@ static void delete_netdev(struct work_struct *work)
 	/* The entry pointer is deleted in device_event() */
 }
 
-int bt_6lowpan_del_conn(struct l2cap_conn *conn)
+static void chan_close_cb(struct l2cap_chan *chan)
 {
 	struct lowpan_dev *entry, *tmp;
 	struct lowpan_dev *dev = NULL;
 	struct lowpan_peer *peer;
 	int err = -ENOENT;
 	unsigned long flags;
-	bool last = false;
+	bool last = false, removed = true;
 
-	if (!conn || !is_bt_6lowpan(conn->hcon))
-		return 0;
+	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;
+	}
 
 	write_lock_irqsave(&devices_lock, flags);
 
 	list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
 		dev = lowpan_dev(entry->netdev);
-		peer = peer_lookup_conn(dev, conn);
+		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 %d", chan,
+			       atomic_read(&chan->kref.refcount));
+
+			l2cap_chan_put(chan);
+			kfree(peer);
 			break;
 		}
 	}
@@ -810,18 +823,363 @@ int bt_6lowpan_del_conn(struct l2cap_conn *conn)
 
 		cancel_delayed_work_sync(&dev->notify_peers);
 
-		/* bt_6lowpan_del_conn() is called with hci dev lock held which
-		 * means that we must delete the netdevice in worker thread.
-		 */
-		INIT_WORK(&entry->delete_netdev, delete_netdev);
-		schedule_work(&entry->delete_netdev);
+		if (!removed) {
+			INIT_WORK(&entry->delete_netdev, delete_netdev);
+			schedule_work(&entry->delete_netdev);
+		}
 	} else {
 		write_unlock_irqrestore(&devices_lock, flags);
 	}
 
+	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);
+
+	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);
+
+	lowpan_cb(skb)->status = 0;
+}
+
+static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
+{
+	return msecs_to_jiffies(1000);
+}
+
+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);
+
 	return err;
 }
 
+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,
+};
+
 static int device_event(struct notifier_block *unused,
 			unsigned long event, void *ptr)
 {
@@ -856,10 +1214,25 @@ static struct notifier_block bt_6lowpan_dev_notifier = {
 
 int bt_6lowpan_init(void)
 {
+	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);
+
 	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
 }
 
-void bt_6lowpan_cleanup(void)
+void bt_6lowpan_exit(void)
 {
+	debugfs_remove(lowpan_psm_debugfs);
+	debugfs_remove(lowpan_control_debugfs);
+
+	if (listen_chan) {
+		l2cap_chan_close(listen_chan, 0);
+		l2cap_chan_put(listen_chan);
+	}
+
 	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
 }
diff --git a/net/bluetooth/6lowpan.h b/net/bluetooth/6lowpan.h
deleted file mode 100644
index 5d281f1eaf55..000000000000
--- a/net/bluetooth/6lowpan.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
-   Copyright (c) 2013 Intel Corp.
-
-   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.
-*/
-
-#ifndef __6LOWPAN_H
-#define __6LOWPAN_H
-
-#include <linux/errno.h>
-#include <linux/skbuff.h>
-#include <net/bluetooth/l2cap.h>
-
-#if IS_ENABLED(CONFIG_BT_6LOWPAN)
-int bt_6lowpan_recv(struct l2cap_conn *conn, struct sk_buff *skb);
-int bt_6lowpan_add_conn(struct l2cap_conn *conn);
-int bt_6lowpan_del_conn(struct l2cap_conn *conn);
-int bt_6lowpan_init(void);
-void bt_6lowpan_cleanup(void);
-#else
-static int bt_6lowpan_recv(struct l2cap_conn *conn, struct sk_buff *skb)
-{
-	return -EOPNOTSUPP;
-}
-static int bt_6lowpan_add_conn(struct l2cap_conn *conn)
-{
-	return -EOPNOTSUPP;
-}
-int bt_6lowpan_del_conn(struct l2cap_conn *conn)
-{
-	return -EOPNOTSUPP;
-}
-static int bt_6lowpan_init(void)
-{
-	return -EOPNOTSUPP;
-}
-static void bt_6lowpan_cleanup(void) { }
-#endif
-
-#endif /* __6LOWPAN_H */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index ddbb084250be..bbfc5455acec 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -928,49 +928,6 @@ static int adv_channel_map_get(void *data, u64 *val)
 DEFINE_SIMPLE_ATTRIBUTE(adv_channel_map_fops, adv_channel_map_get,
 			adv_channel_map_set, "%llu\n");
 
-static ssize_t lowpan_read(struct file *file, char __user *user_buf,
-			   size_t count, loff_t *ppos)
-{
-	struct hci_dev *hdev = file->private_data;
-	char buf[3];
-
-	buf[0] = test_bit(HCI_6LOWPAN_ENABLED, &hdev->dev_flags) ? 'Y' : 'N';
-	buf[1] = '\n';
-	buf[2] = '\0';
-	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
-}
-
-static ssize_t lowpan_write(struct file *fp, const char __user *user_buffer,
-			    size_t count, loff_t *position)
-{
-	struct hci_dev *hdev = fp->private_data;
-	bool enable;
-	char buf[32];
-	size_t buf_size = min(count, (sizeof(buf)-1));
-
-	if (copy_from_user(buf, user_buffer, buf_size))
-		return -EFAULT;
-
-	buf[buf_size] = '\0';
-
-	if (strtobool(buf, &enable) < 0)
-		return -EINVAL;
-
-	if (enable == test_bit(HCI_6LOWPAN_ENABLED, &hdev->dev_flags))
-		return -EALREADY;
-
-	change_bit(HCI_6LOWPAN_ENABLED, &hdev->dev_flags);
-
-	return count;
-}
-
-static const struct file_operations lowpan_debugfs_fops = {
-	.open		= simple_open,
-	.read		= lowpan_read,
-	.write		= lowpan_write,
-	.llseek		= default_llseek,
-};
-
 static int le_auto_conn_show(struct seq_file *sf, void *ptr)
 {
 	struct hci_dev *hdev = sf->private;
@@ -1881,8 +1838,6 @@ static int __hci_init(struct hci_dev *hdev)
 				    hdev, &conn_max_interval_fops);
 		debugfs_create_file("adv_channel_map", 0644, hdev->debugfs,
 				    hdev, &adv_channel_map_fops);
-		debugfs_create_file("6lowpan", 0644, hdev->debugfs, hdev,
-				    &lowpan_debugfs_fops);
 		debugfs_create_file("le_auto_conn", 0644, hdev->debugfs, hdev,
 				    &le_auto_conn_fops);
 		debugfs_create_u16("discov_interleaved_timeout", 0644,
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 15a0a65bf447..e5b430113cfb 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4056,9 +4056,6 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	conn->handle = __le16_to_cpu(ev->handle);
 	conn->state = BT_CONNECTED;
 
-	if (test_bit(HCI_6LOWPAN_ENABLED, &hdev->dev_flags))
-		set_bit(HCI_CONN_6LOWPAN, &conn->flags);
-
 	hci_conn_add_sysfs(conn);
 
 	hci_proto_connect_cfm(conn, ev->status);
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index d0a5fde61a07..cbf6b9d1c404 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -40,7 +40,6 @@
 #include "smp.h"
 #include "a2mp.h"
 #include "amp.h"
-#include "6lowpan.h"
 
 #define LE_FLOWCTL_MAX_CREDITS 65535
 
@@ -205,6 +204,7 @@ done:
 	write_unlock(&chan_list_lock);
 	return err;
 }
+EXPORT_SYMBOL_GPL(l2cap_add_psm);
 
 int l2cap_add_scid(struct l2cap_chan *chan,  __u16 scid)
 {
@@ -437,6 +437,7 @@ struct l2cap_chan *l2cap_chan_create(void)
 
 	return chan;
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_create);
 
 static void l2cap_chan_destroy(struct kref *kref)
 {
@@ -464,6 +465,7 @@ void l2cap_chan_put(struct l2cap_chan *c)
 
 	kref_put(&c->kref, l2cap_chan_destroy);
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_put);
 
 void l2cap_chan_set_defaults(struct l2cap_chan *chan)
 {
@@ -482,6 +484,7 @@ void l2cap_chan_set_defaults(struct l2cap_chan *chan)
 
 	set_bit(FLAG_FORCE_ACTIVE, &chan->flags);
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_set_defaults);
 
 static void l2cap_le_flowctl_init(struct l2cap_chan *chan)
 {
@@ -614,6 +617,7 @@ void l2cap_chan_del(struct l2cap_chan *chan, int err)
 
 	return;
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_del);
 
 void l2cap_conn_update_id_addr(struct hci_conn *hcon)
 {
@@ -717,6 +721,7 @@ void l2cap_chan_close(struct l2cap_chan *chan, int reason)
 		break;
 	}
 }
+EXPORT_SYMBOL(l2cap_chan_close);
 
 static inline u8 l2cap_get_auth_type(struct l2cap_chan *chan)
 {
@@ -1460,8 +1465,6 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
 
 	BT_DBG("");
 
-	bt_6lowpan_add_conn(conn);
-
 	/* Check if we have socket listening on cid */
 	pchan = l2cap_global_chan_by_scid(BT_LISTEN, L2CAP_CID_ATT,
 					  &hcon->src, &hcon->dst);
@@ -2555,6 +2558,7 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len)
 
 	return err;
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_send);
 
 static void l2cap_send_srej(struct l2cap_chan *chan, u16 txseq)
 {
@@ -6933,10 +6937,6 @@ static void l2cap_recv_frame(struct l2cap_conn *conn, struct sk_buff *skb)
 			l2cap_conn_del(conn->hcon, EACCES);
 		break;
 
-	case L2CAP_FC_6LOWPAN:
-		bt_6lowpan_recv(conn, skb);
-		break;
-
 	default:
 		l2cap_data_channel(conn, cid, skb);
 		break;
@@ -7183,6 +7183,7 @@ done:
 	hci_dev_put(hdev);
 	return err;
 }
+EXPORT_SYMBOL_GPL(l2cap_chan_connect);
 
 /* ---- L2CAP interface with lower layer (HCI) ---- */
 
@@ -7245,8 +7246,6 @@ void l2cap_disconn_cfm(struct hci_conn *hcon, u8 reason)
 {
 	BT_DBG("hcon %p reason %d", hcon, reason);
 
-	bt_6lowpan_del_conn(hcon->l2cap_data);
-
 	l2cap_conn_del(hcon, bt_to_errno(reason));
 }
 
@@ -7529,14 +7528,11 @@ int __init l2cap_init(void)
 	debugfs_create_u16("l2cap_le_default_mps", 0644, bt_debugfs,
 			   &le_default_mps);
 
-	bt_6lowpan_init();
-
 	return 0;
 }
 
 void l2cap_exit(void)
 {
-	bt_6lowpan_cleanup();
 	debugfs_remove(l2cap_debugfs);
 	l2cap_cleanup_sockets();
 }