Bluetooth: Add support for reusing the same hci_conn for LE links

As most LE devices leave advertising mode when they enter the connected
state, we may want to "pass" that connection to other users.

The first user will be the pairing procedure, the connection is
established without an associated socket, after the pairing is
complete, userspace may want to discover via GATT what services the
newly bonded device has.

If userspace establishes the connection while the timeout still
hasn't expired, the connection will be re-used.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Tested-by: João Paulo Rechi Vita <jprvita@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo@padovan.org>

net/bluetooth/hci_conn.c

@@ -522,23 +522,27 @@ struct hci_conn *hci_connect(struct hci_dev *hdev, int type, bdaddr_t *dst, __u8
 	BT_DBG("%s dst %s", hdev->name, batostr(dst));
 
 	if (type == LE_LINK) {
-		struct adv_entry *entry;
+		struct adv_entry *entry = NULL;
 
 		le = hci_conn_hash_lookup_ba(hdev, LE_LINK, dst);
-		if (le)
-			return ERR_PTR(-EBUSY);
-
-		entry = hci_find_adv_entry(hdev, dst);
-		if (!entry)
-			return ERR_PTR(-EHOSTUNREACH);
-
-		le = hci_conn_add(hdev, LE_LINK, dst);
-		if (!le)
-			return ERR_PTR(-ENOMEM);
-
-		le->dst_type = entry->bdaddr_type;
+		if (!le) {
+			entry = hci_find_adv_entry(hdev, dst);
+			if (!entry)
+				return ERR_PTR(-EHOSTUNREACH);
+
+			le = hci_conn_add(hdev, LE_LINK, dst);
+			if (!le)
+				return ERR_PTR(-ENOMEM);
+
+			le->dst_type = entry->bdaddr_type;
+			le->pending_sec_level = sec_level;
+			le->sec_level = BT_SECURITY_LOW;
+			le->auth_type = auth_type;
+			hci_le_connect(le);
+		}
 
-		hci_le_connect(le);
+		le->pending_sec_level = sec_level;
+		le->auth_type = auth_type;
 
 		hci_conn_hold(le);
 

net/bluetooth/l2cap_core.c

@@ -917,10 +917,38 @@ static void l2cap_send_conn_req(struct l2cap_chan *chan)
 	l2cap_send_cmd(conn, chan->ident, L2CAP_CONN_REQ, sizeof(req), &req);
 }
 
+static void l2cap_chan_ready(struct l2cap_chan *chan)
+{
+	struct sock *sk = chan->sk;
+	struct sock *parent;
+
+	lock_sock(sk);
+
+	parent = bt_sk(sk)->parent;
+
+	BT_DBG("sk %p, parent %p", sk, parent);
+
+	chan->conf_state = 0;
+	__clear_chan_timer(chan);
+
+	__l2cap_state_change(chan, BT_CONNECTED);
+	sk->sk_state_change(sk);
+
+	if (parent)
+		parent->sk_data_ready(parent, 0);
+
+	release_sock(sk);
+}
+
 static void l2cap_do_start(struct l2cap_chan *chan)
 {
 	struct l2cap_conn *conn = chan->conn;
 
+	if (conn->hcon->type == LE_LINK) {
+		l2cap_chan_ready(chan);
+		return;
+	}
+
 	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) {
 		if (!(conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE))
 			return;
@@ -1156,29 +1184,6 @@ static void l2cap_le_conn_ready(struct l2cap_conn *conn)
 	release_sock(parent);
 }
 
-static void l2cap_chan_ready(struct l2cap_chan *chan)
-{
-	struct sock *sk = chan->sk;
-	struct sock *parent;
-
-	lock_sock(sk);
-
-	parent = bt_sk(sk)->parent;
-
-	BT_DBG("sk %p, parent %p", sk, parent);
-
-	chan->conf_state = 0;
-	__clear_chan_timer(chan);
-
-	__l2cap_state_change(chan, BT_CONNECTED);
-	sk->sk_state_change(sk);
-
-	if (parent)
-		parent->sk_data_ready(parent, 0);
-
-	release_sock(sk);
-}
-
 static void l2cap_conn_ready(struct l2cap_conn *conn)
 {
 	struct l2cap_chan *chan;
@@ -1492,6 +1497,18 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, bdaddr_t *d
 		goto done;
 	}
 
+	if (hcon->type == LE_LINK) {
+		err = 0;
+
+		if (!list_empty(&conn->chan_l)) {
+			err = -EBUSY;
+			hci_conn_put(hcon);
+		}
+
+		if (err)
+			goto done;
+	}
+
 	/* Update source addr of the socket */
 	bacpy(src, conn->src);