2 files changed, 583 insertions, 25 deletions

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index cef1021d5403..8d30a33b27d9 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -1,6 +1,7 @@
 /*
    HIDP implementation for Linux Bluetooth stack (BlueZ).
    Copyright (C) 2003-2004 Marcel Holtmann <marcel@holtmann.org>
+   Copyright (C) 2013 David Herrmann <dh.herrmann@gmail.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2 as
@@ -20,6 +21,7 @@
    SOFTWARE IS DISCLAIMED.
 */
 
+#include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/file.h>
 #include <linux/kthread.h>
@@ -59,6 +61,13 @@ static unsigned char hidp_keycode[256] = {
 
 static unsigned char hidp_mkeyspat[] = { 0x01, 0x01, 0x01, 0x01, 0x01, 0x01 };
 
+static int hidp_session_probe(struct l2cap_conn *conn,
+			      struct l2cap_user *user);
+static void hidp_session_remove(struct l2cap_conn *conn,
+				struct l2cap_user *user);
+static int hidp_session_thread(void *arg);
+static void hidp_session_terminate(struct hidp_session *s);
+
 static inline void hidp_schedule(struct hidp_session *session)
 {
 	struct sock *ctrl_sk = session->ctrl_sock->sk;
@@ -838,7 +847,7 @@ static int hidp_setup_input(struct hidp_session *session,
 		input->relbit[0] |= BIT_MASK(REL_WHEEL);
 	}
 
-	input->dev.parent = &session->conn->dev;
+	input->dev.parent = &session->hconn->dev;
 
 	input->event = hidp_input_event;
 
@@ -942,7 +951,7 @@ static int hidp_setup_hid(struct hidp_session *session,
 	snprintf(hid->uniq, sizeof(hid->uniq), "%pMR",
 		 &bt_sk(session->ctrl_sock->sk)->dst);
 
-	hid->dev.parent = &session->conn->dev;
+	hid->dev.parent = &session->hconn->dev;
 	hid->ll_driver = &hidp_hid_driver;
 
 	hid->hid_get_raw_report = hidp_get_raw_report;
@@ -964,6 +973,543 @@ fault:
 	return err;
 }
 
+/* initialize session devices */
+static int hidp_session_dev_init(struct hidp_session *session,
+				 struct hidp_connadd_req *req)
+{
+	int ret;
+
+	if (req->rd_size > 0) {
+		ret = hidp_setup_hid(session, req);
+		if (ret && ret != -ENODEV)
+			return ret;
+	}
+
+	if (!session->hid) {
+		ret = hidp_setup_input(session, req);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* destroy session devices */
+static void hidp_session_dev_destroy(struct hidp_session *session)
+{
+	if (session->hid)
+		put_device(&session->hid->dev);
+	else if (session->input)
+		input_put_device(session->input);
+
+	kfree(session->rd_data);
+	session->rd_data = NULL;
+}
+
+/* add HID/input devices to their underlying bus systems */
+static int hidp_session_dev_add(struct hidp_session *session)
+{
+	int ret;
+
+	/* Both HID and input systems drop a ref-count when unregistering the
+	 * device but they don't take a ref-count when registering them. Work
+	 * around this by explicitly taking a refcount during registration
+	 * which is dropped automatically by unregistering the devices. */
+
+	if (session->hid) {
+		ret = hid_add_device(session->hid);
+		if (ret)
+			return ret;
+		get_device(&session->hid->dev);
+	} else if (session->input) {
+		ret = input_register_device(session->input);
+		if (ret)
+			return ret;
+		input_get_device(session->input);
+	}
+
+	return 0;
+}
+
+/* remove HID/input devices from their bus systems */
+static void hidp_session_dev_del(struct hidp_session *session)
+{
+	if (session->hid)
+		hid_destroy_device(session->hid);
+	else if (session->input)
+		input_unregister_device(session->input);
+}
+
+/*
+ * Create new session object
+ * Allocate session object, initialize static fields, copy input data into the
+ * object and take a reference to all sub-objects.
+ * This returns 0 on success and puts a pointer to the new session object in
+ * \out. Otherwise, an error code is returned.
+ * The new session object has an initial ref-count of 1.
+ */
+static int hidp_session_new(struct hidp_session **out, const bdaddr_t *bdaddr,
+			    struct socket *ctrl_sock,
+			    struct socket *intr_sock,
+			    struct hidp_connadd_req *req,
+			    struct l2cap_conn *conn)
+{
+	struct hidp_session *session;
+	int ret;
+	struct bt_sock *ctrl, *intr;
+
+	ctrl = bt_sk(ctrl_sock->sk);
+	intr = bt_sk(intr_sock->sk);
+
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	if (!session)
+		return -ENOMEM;
+
+	/* object and runtime management */
+	kref_init(&session->ref);
+	atomic_set(&session->state, HIDP_SESSION_IDLING);
+	init_waitqueue_head(&session->state_queue);
+	session->flags = req->flags & (1 << HIDP_BLUETOOTH_VENDOR_ID);
+
+	/* connection management */
+	bacpy(&session->bdaddr, bdaddr);
+	session->conn = conn;
+	session->user.probe = hidp_session_probe;
+	session->user.remove = hidp_session_remove;
+	session->ctrl_sock = ctrl_sock;
+	session->intr_sock = intr_sock;
+	skb_queue_head_init(&session->ctrl_transmit);
+	skb_queue_head_init(&session->intr_transmit);
+	session->ctrl_mtu = min_t(uint, l2cap_pi(ctrl)->chan->omtu,
+					l2cap_pi(ctrl)->chan->imtu);
+	session->intr_mtu = min_t(uint, l2cap_pi(intr)->chan->omtu,
+					l2cap_pi(intr)->chan->imtu);
+	session->idle_to = req->idle_to;
+
+	/* device management */
+	setup_timer(&session->timer, hidp_idle_timeout,
+		    (unsigned long)session);
+
+	/* session data */
+	mutex_init(&session->report_mutex);
+	init_waitqueue_head(&session->report_queue);
+
+	ret = hidp_session_dev_init(session, req);
+	if (ret)
+		goto err_free;
+
+	l2cap_conn_get(session->conn);
+	get_file(session->intr_sock->file);
+	get_file(session->ctrl_sock->file);
+	*out = session;
+	return 0;
+
+err_free:
+	kfree(session);
+	return ret;
+}
+
+/* increase ref-count of the given session by one */
+static void hidp_session_get(struct hidp_session *session)
+{
+	kref_get(&session->ref);
+}
+
+/* release callback */
+static void session_free(struct kref *ref)
+{
+	struct hidp_session *session = container_of(ref, struct hidp_session,
+						    ref);
+
+	hidp_session_dev_destroy(session);
+	skb_queue_purge(&session->ctrl_transmit);
+	skb_queue_purge(&session->intr_transmit);
+	fput(session->intr_sock->file);
+	fput(session->ctrl_sock->file);
+	l2cap_conn_put(session->conn);
+	kfree(session);
+}
+
+/* decrease ref-count of the given session by one */
+static void hidp_session_put(struct hidp_session *session)
+{
+	kref_put(&session->ref, session_free);
+}
+
+/*
+ * Search the list of active sessions for a session with target address
+ * \bdaddr. You must hold at least a read-lock on \hidp_session_sem. As long as
+ * you do not release this lock, the session objects cannot vanish and you can
+ * safely take a reference to the session yourself.
+ */
+static struct hidp_session *__hidp_session_find(const bdaddr_t *bdaddr)
+{
+	struct hidp_session *session;
+
+	list_for_each_entry(session, &hidp_session_list, list) {
+		if (!bacmp(bdaddr, &session->bdaddr))
+			return session;
+	}
+
+	return NULL;
+}
+
+/*
+ * Same as __hidp_session_find() but no locks must be held. This also takes a
+ * reference of the returned session (if non-NULL) so you must drop this
+ * reference if you no longer use the object.
+ */
+static struct hidp_session *hidp_session_find(const bdaddr_t *bdaddr)
+{
+	struct hidp_session *session;
+
+	down_read(&hidp_session_sem);
+
+	session = __hidp_session_find(bdaddr);
+	if (session)
+		hidp_session_get(session);
+
+	up_read(&hidp_session_sem);
+
+	return session;
+}
+
+/*
+ * Start session synchronously
+ * This starts a session thread and waits until initialization
+ * is done or returns an error if it couldn't be started.
+ * If this returns 0 the session thread is up and running. You must call
+ * hipd_session_stop_sync() before deleting any runtime resources.
+ */
+static int hidp_session_start_sync(struct hidp_session *session)
+{
+	unsigned int vendor, product;
+
+	if (session->hid) {
+		vendor  = session->hid->vendor;
+		product = session->hid->product;
+	} else if (session->input) {
+		vendor  = session->input->id.vendor;
+		product = session->input->id.product;
+	} else {
+		vendor = 0x0000;
+		product = 0x0000;
+	}
+
+	session->task = kthread_run(hidp_session_thread, session,
+				    "khidpd_%04x%04x", vendor, product);
+	if (IS_ERR(session->task))
+		return PTR_ERR(session->task);
+
+	while (atomic_read(&session->state) <= HIDP_SESSION_IDLING)
+		wait_event(session->state_queue,
+			   atomic_read(&session->state) > HIDP_SESSION_IDLING);
+
+	return 0;
+}
+
+/*
+ * Terminate session thread
+ * Wake up session thread and notify it to stop. This is asynchronous and
+ * returns immediately. Call this whenever a runtime error occurs and you want
+ * the session to stop.
+ * Note: wake_up_process() performs any necessary memory-barriers for us.
+ */
+static void hidp_session_terminate(struct hidp_session *session)
+{
+	atomic_inc(&session->terminate);
+	wake_up_process(session->task);
+}
+
+/*
+ * Probe HIDP session
+ * This is called from the l2cap_conn core when our l2cap_user object is bound
+ * to the hci-connection. We get the session via the \user object and can now
+ * start the session thread, register the HID/input devices and link it into
+ * the global session list.
+ * The global session-list owns its own reference to the session object so you
+ * can drop your own reference after registering the l2cap_user object.
+ */
+static int hidp_session_probe(struct l2cap_conn *conn,
+			      struct l2cap_user *user)
+{
+	struct hidp_session *session = container_of(user,
+						    struct hidp_session,
+						    user);
+	struct hidp_session *s;
+	int ret;
+
+	down_write(&hidp_session_sem);
+
+	/* check that no other session for this device exists */
+	s = __hidp_session_find(&session->bdaddr);
+	if (s) {
+		ret = -EEXIST;
+		goto out_unlock;
+	}
+
+	ret = hidp_session_start_sync(session);
+	if (ret)
+		goto out_unlock;
+
+	ret = hidp_session_dev_add(session);
+	if (ret)
+		goto out_stop;
+
+	hidp_session_get(session);
+	list_add(&session->list, &hidp_session_list);
+	ret = 0;
+	goto out_unlock;
+
+out_stop:
+	hidp_session_terminate(session);
+out_unlock:
+	up_write(&hidp_session_sem);
+	return ret;
+}
+
+/*
+ * Remove HIDP session
+ * Called from the l2cap_conn core when either we explicitly unregistered
+ * the l2cap_user object or if the underlying connection is shut down.
+ * We signal the hidp-session thread to shut down, unregister the HID/input
+ * devices and unlink the session from the global list.
+ * This drops the reference to the session that is owned by the global
+ * session-list.
+ * Note: We _must_ not synchronosly wait for the session-thread to shut down.
+ * This is, because the session-thread might be waiting for an HCI lock that is
+ * held while we are called. Therefore, we only unregister the devices and
+ * notify the session-thread to terminate. The thread itself owns a reference
+ * to the session object so it can safely shut down.
+ */
+static void hidp_session_remove(struct l2cap_conn *conn,
+				struct l2cap_user *user)
+{
+	struct hidp_session *session = container_of(user,
+						    struct hidp_session,
+						    user);
+
+	down_write(&hidp_session_sem);
+
+	hidp_session_terminate(session);
+	hidp_session_dev_del(session);
+	list_del(&session->list);
+
+	up_write(&hidp_session_sem);
+
+	hidp_session_put(session);
+}
+
+/*
+ * Session Worker
+ * This performs the actual main-loop of the HIDP worker. We first check
+ * whether the underlying connection is still alive, then parse all pending
+ * messages and finally send all outstanding messages.
+ */
+static void hidp_session_run(struct hidp_session *session)
+{
+	struct sock *ctrl_sk = session->ctrl_sock->sk;
+	struct sock *intr_sk = session->intr_sock->sk;
+	struct sk_buff *skb;
+
+	for (;;) {
+		/*
+		 * This thread can be woken up two ways:
+		 *  - You call hidp_session_terminate() which sets the
+		 *    session->terminate flag and wakes this thread up.
+		 *  - Via modifying the socket state of ctrl/intr_sock. This
+		 *    thread is woken up by ->sk_state_changed().
+		 *
+		 * Note: set_current_state() performs any necessary
+		 * memory-barriers for us.
+		 */
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (atomic_read(&session->terminate))
+			break;
+
+		if (ctrl_sk->sk_state != BT_CONNECTED ||
+		    intr_sk->sk_state != BT_CONNECTED)
+			break;
+
+		/* parse incoming intr-skbs */
+		while ((skb = skb_dequeue(&intr_sk->sk_receive_queue))) {
+			skb_orphan(skb);
+			if (!skb_linearize(skb))
+				hidp_recv_intr_frame(session, skb);
+			else
+				kfree_skb(skb);
+		}
+
+		/* send pending intr-skbs */
+		hidp_process_intr_transmit(session);
+
+		/* parse incoming ctrl-skbs */
+		while ((skb = skb_dequeue(&ctrl_sk->sk_receive_queue))) {
+			skb_orphan(skb);
+			if (!skb_linearize(skb))
+				hidp_recv_ctrl_frame(session, skb);
+			else
+				kfree_skb(skb);
+		}
+
+		/* send pending ctrl-skbs */
+		hidp_process_ctrl_transmit(session);
+
+		schedule();
+	}
+
+	atomic_inc(&session->terminate);
+	set_current_state(TASK_RUNNING);
+}
+
+/*
+ * HIDP session thread
+ * This thread runs the I/O for a single HIDP session. Startup is synchronous
+ * which allows us to take references to ourself here instead of doing that in
+ * the caller.
+ * When we are ready to run we notify the caller and call hidp_session_run().
+ */
+static int hidp_session_thread(void *arg)
+{
+	struct hidp_session *session = arg;
+	wait_queue_t ctrl_wait, intr_wait;
+
+	BT_DBG("session %p", session);
+
+	/* initialize runtime environment */
+	hidp_session_get(session);
+	__module_get(THIS_MODULE);
+	set_user_nice(current, -15);
+	hidp_set_timer(session);
+
+	init_waitqueue_entry(&ctrl_wait, current);
+	init_waitqueue_entry(&intr_wait, current);
+	add_wait_queue(sk_sleep(session->ctrl_sock->sk), &ctrl_wait);
+	add_wait_queue(sk_sleep(session->intr_sock->sk), &intr_wait);
+	/* This memory barrier is paired with wq_has_sleeper(). See
+	 * sock_poll_wait() for more information why this is needed. */
+	smp_mb();
+
+	/* notify synchronous startup that we're ready */
+	atomic_inc(&session->state);
+	wake_up(&session->state_queue);
+
+	/* run session */
+	hidp_session_run(session);
+
+	/* cleanup runtime environment */
+	remove_wait_queue(sk_sleep(session->intr_sock->sk), &intr_wait);
+	remove_wait_queue(sk_sleep(session->intr_sock->sk), &ctrl_wait);
+	wake_up_interruptible(&session->report_queue);
+	hidp_del_timer(session);
+
+	/*
+	 * If we stopped ourself due to any internal signal, we should try to
+	 * unregister our own session here to avoid having it linger until the
+	 * parent l2cap_conn dies or user-space cleans it up.
+	 * This does not deadlock as we don't do any synchronous shutdown.
+	 * Instead, this call has the same semantics as if user-space tried to
+	 * delete the session.
+	 */
+	l2cap_unregister_user(session->conn, &session->user);
+	hidp_session_put(session);
+
+	module_put_and_exit(0);
+	return 0;
+}
+
+static int hidp_verify_sockets(struct socket *ctrl_sock,
+			       struct socket *intr_sock)
+{
+	struct bt_sock *ctrl, *intr;
+	struct hidp_session *session;
+
+	if (!l2cap_is_socket(ctrl_sock) || !l2cap_is_socket(intr_sock))
+		return -EINVAL;
+
+	ctrl = bt_sk(ctrl_sock->sk);
+	intr = bt_sk(intr_sock->sk);
+
+	if (bacmp(&ctrl->src, &intr->src) || bacmp(&ctrl->dst, &intr->dst))
+		return -ENOTUNIQ;
+	if (ctrl->sk.sk_state != BT_CONNECTED ||
+	    intr->sk.sk_state != BT_CONNECTED)
+		return -EBADFD;
+
+	/* early session check, we check again during session registration */
+	session = hidp_session_find(&ctrl->dst);
+	if (session) {
+		hidp_session_put(session);
+		return -EEXIST;
+	}
+
+	return 0;
+}
+
+int hidp_connection_add(struct hidp_connadd_req *req,
+			struct socket *ctrl_sock,
+			struct socket *intr_sock)
+{
+	struct hidp_session *session;
+	struct l2cap_conn *conn;
+	struct l2cap_chan *chan = l2cap_pi(ctrl_sock->sk)->chan;
+	int ret;
+
+	ret = hidp_verify_sockets(ctrl_sock, intr_sock);
+	if (ret)
+		return ret;
+
+	conn = NULL;
+	l2cap_chan_lock(chan);
+	if (chan->conn) {
+		l2cap_conn_get(chan->conn);
+		conn = chan->conn;
+	}
+	l2cap_chan_unlock(chan);
+
+	if (!conn)
+		return -EBADFD;
+
+	ret = hidp_session_new(&session, &bt_sk(ctrl_sock->sk)->dst, ctrl_sock,
+			       intr_sock, req, conn);
+	if (ret)
+		goto out_conn;
+
+	ret = l2cap_register_user(conn, &session->user);
+	if (ret)
+		goto out_session;
+
+	ret = 0;
+
+out_session:
+	hidp_session_put(session);
+out_conn:
+	l2cap_conn_put(conn);
+	return ret;
+}
+
+int hidp_connection_del(struct hidp_conndel_req *req)
+{
+	struct hidp_session *session;
+
+	session = hidp_session_find(&req->bdaddr);
+	if (!session)
+		return -ENOENT;
+
+	if (req->flags & (1 << HIDP_VIRTUAL_CABLE_UNPLUG))
+		hidp_send_ctrl_message(session,
+				       HIDP_TRANS_HID_CONTROL |
+				         HIDP_CTRL_VIRTUAL_CABLE_UNPLUG,
+				       NULL, 0);
+	else
+		l2cap_unregister_user(session->conn, &session->user);
+
+	hidp_session_put(session);
+
+	return 0;
+}
+
 int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock, struct socket *intr_sock)
 {
 	struct hidp_session *session, *s;
@@ -1006,8 +1552,8 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
 	session->ctrl_sock = ctrl_sock;
 	session->intr_sock = intr_sock;
 
-	session->conn = hidp_get_connection(session);
-	if (!session->conn) {
+	session->hconn = hidp_get_connection(session);
+	if (!session->hconn) {
 		err = -ENOTCONN;
 		goto failed;
 	}
@@ -1208,6 +1754,7 @@ module_init(hidp_init);
 module_exit(hidp_exit);
 
 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
+MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
 MODULE_DESCRIPTION("Bluetooth HIDP ver " VERSION);
 MODULE_VERSION(VERSION);
 MODULE_LICENSE("GPL");
diff --git a/net/bluetooth/hidp/hidp.h b/net/bluetooth/hidp/hidp.h
index c84442061793..c4fb980c2434 100644
--- a/net/bluetooth/hidp/hidp.h
+++ b/net/bluetooth/hidp/hidp.h
@@ -24,7 +24,9 @@
 #define __HIDP_H
 
 #include <linux/types.h>
+#include <linux/kref.h>
 #include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/l2cap.h>
 
 /* HIDP header masks */
 #define HIDP_HEADER_TRANS_MASK			0xf0
@@ -119,42 +121,55 @@ struct hidp_connlist_req {
 	struct hidp_conninfo __user *ci;
 };
 
+int hidp_connection_add(struct hidp_connadd_req *req, struct socket *ctrl_sock, struct socket *intr_sock);
+int hidp_connection_del(struct hidp_conndel_req *req);
 int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock, struct socket *intr_sock);
 int hidp_del_connection(struct hidp_conndel_req *req);
 int hidp_get_connlist(struct hidp_connlist_req *req);
 int hidp_get_conninfo(struct hidp_conninfo *ci);
 
+enum hidp_session_state {
+	HIDP_SESSION_IDLING,
+	HIDP_SESSION_RUNNING,
+};
+
 /* HIDP session defines */
 struct hidp_session {
 	struct list_head list;
+	struct kref ref;
 
-	struct hci_conn *conn;
+	/* runtime management */
+	atomic_t state;
+	wait_queue_head_t state_queue;
+	atomic_t terminate;
+	struct task_struct *task;
+	unsigned long flags;
 
+	/* connection management */
+	bdaddr_t bdaddr;
+	struct hci_conn *hconn;
+	struct l2cap_conn *conn;
+	struct l2cap_user user;
 	struct socket *ctrl_sock;
 	struct socket *intr_sock;
-
-	bdaddr_t bdaddr;
-
-	unsigned long flags;
-	unsigned long idle_to;
-
+	struct sk_buff_head ctrl_transmit;
+	struct sk_buff_head intr_transmit;
 	uint ctrl_mtu;
 	uint intr_mtu;
+	unsigned long idle_to;
 
-	atomic_t terminate;
-	struct task_struct *task;
-
-	unsigned char keys[8];
-	unsigned char leds;
-
+	/* device management */
 	struct input_dev *input;
-
 	struct hid_device *hid;
-
 	struct timer_list timer;
 
-	struct sk_buff_head ctrl_transmit;
-	struct sk_buff_head intr_transmit;
+	/* Report descriptor */
+	__u8 *rd_data;
+	uint rd_size;
+
+	/* session data */
+	unsigned char keys[8];
+	unsigned char leds;
 
 	/* Used in hidp_get_raw_report() */
 	int waiting_report_type; /* HIDP_DATA_RTYPE_* */
@@ -166,10 +181,6 @@ struct hidp_session {
 	/* Used in hidp_output_raw_report() */
 	int output_report_success; /* boolean */
 
-	/* Report descriptor */
-	__u8 *rd_data;
-	uint rd_size;
-
 	wait_queue_head_t startup_queue;
 	int waiting_for_startup;
 };