[PATCH v4 0/5] L2CAP updates for FCS, valid PSMs, and stream recv

[PATCH v4 0/5] L2CAP updates for FCS, valid PSMs, and stream recv

[Mat Martineau]

The previous version of this patch set was "[PATCH v3 0/9] Bluetooth:
L2CAP updates for PSM validation and ERTM" - four patches were already
merged, and this group of patches incorporates additional feedback
from the v3 iteration.

[PATCH 1/5] Bluetooth: Only enable L2CAP FCS for ERTM or streaming.

[Mat Martineau]

This fixes a bug which caused the FCS setting to show L2CAP_FCS_CRC16
with L2CAP modes other than ERTM or streaming.  At present, this only
affects the FCS value shown with getsockopt() for basic mode.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 net/bluetooth/l2cap.c |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index fadf26b..c784703 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3071,6 +3071,17 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd
 	return 0;
 }
 
+static inline void set_default_fcs(struct l2cap_pinfo *pi)
+{
+	/* FCS is enabled only in ERTM or streaming mode, if one or both
+	 * sides request it.
+	 */
+	if (pi->mode != L2CAP_MODE_ERTM && pi->mode != L2CAP_MODE_STREAMING)
+		pi->fcs = L2CAP_FCS_NONE;
+	else if (!(pi->conf_state & L2CAP_CONF_NO_FCS_RECV))
+		pi->fcs = L2CAP_FCS_CRC16;
+}
+
 static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u16 cmd_len, u8 *data)
 {
 	struct l2cap_conf_req *req = (struct l2cap_conf_req *) data;
@@ -3135,9 +3146,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 		goto unlock;
 
 	if (l2cap_pi(sk)->conf_state & L2CAP_CONF_INPUT_DONE) {
-		if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) ||
-		    l2cap_pi(sk)->fcs != L2CAP_FCS_NONE)
-			l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16;
+		set_default_fcs(l2cap_pi(sk));
 
 		sk->sk_state = BT_CONNECTED;
 
@@ -3225,9 +3234,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
 	l2cap_pi(sk)->conf_state |= L2CAP_CONF_INPUT_DONE;
 
 	if (l2cap_pi(sk)->conf_state & L2CAP_CONF_OUTPUT_DONE) {
-		if (!(l2cap_pi(sk)->conf_state & L2CAP_CONF_NO_FCS_RECV) ||
-		    l2cap_pi(sk)->fcs != L2CAP_FCS_NONE)
-			l2cap_pi(sk)->fcs = L2CAP_FCS_CRC16;
+		set_default_fcs(l2cap_pi(sk));
 
 		sk->sk_state = BT_CONNECTED;
 		l2cap_pi(sk)->next_tx_seq = 0;
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH 1/5] Bluetooth: Only enable L2CAP FCS for ERTM or streaming.

[Marcel Holtmann]

Hi Mat,

> This fixes a bug which caused the FCS setting to show L2CAP_FCS_CRC16
> with L2CAP modes other than ERTM or streaming.  At present, this only
> affects the FCS value shown with getsockopt() for basic mode.
> 
> Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
> ---
>  net/bluetooth/l2cap.c |   19 +++++++++++++------
>  1 files changed, 13 insertions(+), 6 deletions(-)

patch has been applied, but please stop adding a . at the end of your
subject line ;)

Regards

Marcel

[PATCH 2/5] Bluetooth: Validate PSM values in calls to connect() and bind().

[Mat Martineau]

Valid L2CAP PSMs are odd numbers, and the least significant bit of the
most significant byte must be 0.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 net/bluetooth/l2cap.c |   23 +++++++++++++++++++----
 1 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index c784703..61aa961 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1008,10 +1008,19 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
 		goto done;
 	}
 
-	if (la.l2_psm && __le16_to_cpu(la.l2_psm) < 0x1001 &&
-				!capable(CAP_NET_BIND_SERVICE)) {
-		err = -EACCES;
-		goto done;
+	/* If specified, PSM must be odd and lsb of upper byte must be 0 */
+	if (la.l2_psm) {
+		__u16 psm = __le16_to_cpu(la.l2_psm);
+
+		if ((psm & 0x0101) != 0x0001) {
+			err = -EINVAL;
+			goto done;
+		}
+
+		if (psm < 0x1001 && !capable(CAP_NET_BIND_SERVICE)) {
+			err = -EACCES;
+			goto done;
+		}
 	}
 
 	write_lock_bh(&l2cap_sk_list.lock);
@@ -1190,6 +1199,12 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
 		goto done;
 	}
 
+	/* PSM must be odd and lsb of upper byte must be 0 */
+	if ((__le16_to_cpu(la.l2_psm) & 0x0101) != 0x0001) {
+		err = -EINVAL;
+		goto done;
+	}
+
 	/* Set destination address and psm */
 	bacpy(&bt_sk(sk)->dst, &la.l2_bdaddr);
 	l2cap_pi(sk)->psm = la.l2_psm;
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH 2/5] Bluetooth: Validate PSM values in calls to connect() and bind().

[Marcel Holtmann]

Hi Mat,

> Valid L2CAP PSMs are odd numbers, and the least significant bit of the
> most significant byte must be 0.
> 
> Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
> ---
>  net/bluetooth/l2cap.c |   23 +++++++++++++++++++----
>  1 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
> index c784703..61aa961 100644
> --- a/net/bluetooth/l2cap.c
> +++ b/net/bluetooth/l2cap.c
> @@ -1008,10 +1008,19 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
>  		goto done;
>  	}
>  
> -	if (la.l2_psm && __le16_to_cpu(la.l2_psm) < 0x1001 &&
> -				!capable(CAP_NET_BIND_SERVICE)) {
> -		err = -EACCES;
> -		goto done;
> +	/* If specified, PSM must be odd and lsb of upper byte must be 0 */
> +	if (la.l2_psm) {
> +		__u16 psm = __le16_to_cpu(la.l2_psm);
> +

I would just put the comment here:

                  /* PSM must be odd and lsb of upper byte must be 0 */
> +		if ((psm & 0x0101) != 0x0001) {
> +			err = -EINVAL;
> +			goto done;
> +		}

And then while you at it:

                  /* Restrict usage of well known PSMs */
> +		if (psm < 0x1001 && !capable(CAP_NET_BIND_SERVICE)) {
> +			err = -EACCES;
> +			goto done;
> +		}
>  	}

Maybe there is actually a second place for adding that comment.

Otherwise I am fine with this, but since it is not a regression, this
will be only taking in the next tree.

Regards

Marcel

[PATCH 3/5] Bluetooth: Add common code for stream-oriented recvmsg()

[Mat Martineau]

This commit adds a bt_sock_stream_recvmsg() function for use by any
Bluetooth code that uses SOCK_STREAM sockets.  This code is copied
from rfcomm_sock_recvmsg() with minimal modifications to remove
RFCOMM-specific functionality and improve readability.

L2CAP (with the SOCK_STREAM socket type) and RFCOMM have common needs
when it comes to reading data.  Proper stream read semantics require
that applications can read from a stream one byte at a time and not
lose any data.  The RFCOMM code already operated on and pulled data
from the underlying L2CAP socket, so very few changes were required to
make the code more generic for use with non-RFCOMM data over L2CAP.

Applications that need more awareness of L2CAP frame boundaries are
still free to use SOCK_SEQPACKET sockets, and may verify that they
connection did not fall back to basic mode by calling getsockopt().

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 include/net/bluetooth/bluetooth.h |    2 +
 net/bluetooth/af_bluetooth.c      |  109 +++++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+), 0 deletions(-)

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 27a902d..08b6c2a 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -126,6 +126,8 @@ int  bt_sock_unregister(int proto);
 void bt_sock_link(struct bt_sock_list *l, struct sock *s);
 void bt_sock_unlink(struct bt_sock_list *l, struct sock *s);
 int  bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len, int flags);
+int  bt_sock_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
+			struct msghdr *msg, size_t len, int flags);
 uint bt_sock_poll(struct file * file, struct socket *sock, poll_table *wait);
 int  bt_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
 int  bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo);
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 421c45b..77a26fe 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -265,6 +265,115 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 }
 EXPORT_SYMBOL(bt_sock_recvmsg);
 
+static long bt_sock_data_wait(struct sock *sk, long timeo)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (!skb_queue_empty(&sk->sk_receive_queue))
+			break;
+
+		if (sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN))
+			break;
+
+		if (signal_pending(current) || !timeo)
+			break;
+
+		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		release_sock(sk);
+		timeo = schedule_timeout(timeo);
+		lock_sock(sk);
+		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return timeo;
+}
+
+int bt_sock_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
+			       struct msghdr *msg, size_t size, int flags)
+{
+	struct sock *sk = sock->sk;
+	int err = 0;
+	size_t target, copied = 0;
+	long timeo;
+
+	if (flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	msg->msg_namelen = 0;
+
+	BT_DBG("sk %p size %zu", sk, size);
+
+	lock_sock(sk);
+
+	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
+	timeo  = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+	do {
+		struct sk_buff *skb;
+		int chunk;
+
+		skb = skb_dequeue(&sk->sk_receive_queue);
+		if (!skb) {
+			if (copied >= target)
+				break;
+
+			if ((err = sock_error(sk)) != 0)
+				break;
+			if (sk->sk_shutdown & RCV_SHUTDOWN)
+				break;
+
+			err = -EAGAIN;
+			if (!timeo)
+				break;
+
+			timeo = bt_sock_data_wait(sk, timeo);
+
+			if (signal_pending(current)) {
+				err = sock_intr_errno(timeo);
+				goto out;
+			}
+			continue;
+		}
+
+		chunk = min_t(unsigned int, skb->len, size);
+		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
+			skb_queue_head(&sk->sk_receive_queue, skb);
+			if (!copied)
+				copied = -EFAULT;
+			break;
+		}
+		copied += chunk;
+		size   -= chunk;
+
+		sock_recv_ts_and_drops(msg, sk, skb);
+
+		if (!(flags & MSG_PEEK)) {
+			skb_pull(skb, chunk);
+			if (skb->len) {
+				skb_queue_head(&sk->sk_receive_queue, skb);
+				break;
+			}
+			kfree_skb(skb);
+
+		} else {
+			/* put message back and return */
+			skb_queue_head(&sk->sk_receive_queue, skb);
+			break;
+		}
+	} while (size);
+
+out:
+	release_sock(sk);
+	return copied ? : err;
+}
+EXPORT_SYMBOL(bt_sock_stream_recvmsg);
+
 static inline unsigned int bt_accept_poll(struct sock *parent)
 {
 	struct list_head *p, *n;
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

[PATCH 4/5] Bluetooth: Use common SOCK_STREAM receive code in RFCOMM.

[Mat Martineau]

To reduce code duplication, have rfcomm_sock_recvmsg() call
bt_sock_stream_recvmsg().  The common bt_sock_stream_recvmsg()
code is nearly identical, with the RFCOMM-specific functionality
for deferred setup and connection unthrottling left in
rfcomm_sock_recvmsg().

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 net/bluetooth/rfcomm/sock.c |  104 +++----------------------------------------
 1 files changed, 6 insertions(+), 98 deletions(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 44a6232..4396f47 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -617,121 +617,29 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 	return sent;
 }
 
-static long rfcomm_sock_data_wait(struct sock *sk, long timeo)
-{
-	DECLARE_WAITQUEUE(wait, current);
-
-	add_wait_queue(sk_sleep(sk), &wait);
-	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		if (!skb_queue_empty(&sk->sk_receive_queue) ||
-		    sk->sk_err ||
-		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
-		    signal_pending(current) ||
-		    !timeo)
-			break;
-
-		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
-		release_sock(sk);
-		timeo = schedule_timeout(timeo);
-		lock_sock(sk);
-		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
-	}
-
-	__set_current_state(TASK_RUNNING);
-	remove_wait_queue(sk_sleep(sk), &wait);
-	return timeo;
-}
-
 static int rfcomm_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 			       struct msghdr *msg, size_t size, int flags)
 {
 	struct sock *sk = sock->sk;
 	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
-	int err = 0;
-	size_t target, copied = 0;
-	long timeo;
+	int len;
 
 	if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
 		rfcomm_dlc_accept(d);
 		return 0;
 	}
 
-	if (flags & MSG_OOB)
-		return -EOPNOTSUPP;
-
-	msg->msg_namelen = 0;
-
-	BT_DBG("sk %p size %zu", sk, size);
+	len = bt_sock_stream_recvmsg(iocb, sock, msg, size, flags);
 
 	lock_sock(sk);
+	if (!(flags & MSG_PEEK) && len > 0)
+		atomic_sub(len, &sk->sk_rmem_alloc);
 
-	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
-	timeo  = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
-
-	do {
-		struct sk_buff *skb;
-		int chunk;
-
-		skb = skb_dequeue(&sk->sk_receive_queue);
-		if (!skb) {
-			if (copied >= target)
-				break;
-
-			if ((err = sock_error(sk)) != 0)
-				break;
-			if (sk->sk_shutdown & RCV_SHUTDOWN)
-				break;
-
-			err = -EAGAIN;
-			if (!timeo)
-				break;
-
-			timeo = rfcomm_sock_data_wait(sk, timeo);
-
-			if (signal_pending(current)) {
-				err = sock_intr_errno(timeo);
-				goto out;
-			}
-			continue;
-		}
-
-		chunk = min_t(unsigned int, skb->len, size);
-		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
-			skb_queue_head(&sk->sk_receive_queue, skb);
-			if (!copied)
-				copied = -EFAULT;
-			break;
-		}
-		copied += chunk;
-		size   -= chunk;
-
-		sock_recv_ts_and_drops(msg, sk, skb);
-
-		if (!(flags & MSG_PEEK)) {
-			atomic_sub(chunk, &sk->sk_rmem_alloc);
-
-			skb_pull(skb, chunk);
-			if (skb->len) {
-				skb_queue_head(&sk->sk_receive_queue, skb);
-				break;
-			}
-			kfree_skb(skb);
-
-		} else {
-			/* put message back and return */
-			skb_queue_head(&sk->sk_receive_queue, skb);
-			break;
-		}
-	} while (size);
-
-out:
 	if (atomic_read(&sk->sk_rmem_alloc) <= (sk->sk_rcvbuf >> 2))
 		rfcomm_dlc_unthrottle(rfcomm_pi(sk)->dlc);
-
 	release_sock(sk);
-	return copied ? : err;
+
+	return len;
 }
 
 static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname, char __user *optval, unsigned int optlen)
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

[PATCH 5/5] Bluetooth: Use a stream-oriented recvmsg with SOCK_STREAM L2CAP sockets.

[Mat Martineau]

L2CAP ERTM sockets can be opened with the SOCK_STREAM socket type,
which is a mandatory request for ERTM mode.

However, these sockets still have SOCK_SEQPACKET read semantics when
bt_sock_recvmsg() is used to pull data from the receive queue.  If the
application is only reading part of a frame, then the unread portion
of the frame is discarded.  If the application requests more bytes
than are in the current frame, only the current frame's data is
returned.

This patch utilizes common code derived from RFCOMM's recvmsg()
function to make L2CAP SOCK_STREAM reads behave like RFCOMM reads (and
other SOCK_STREAM sockets in general).  The application may read one
byte at a time from the input stream and not lose any data, and may
also read across L2CAP frame boundaries.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 net/bluetooth/l2cap.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 61aa961..8d362d7 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1959,6 +1959,9 @@ static int l2cap_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct ms
 
 	release_sock(sk);
 
+	if (sock->type == SOCK_STREAM)
+		return bt_sock_stream_recvmsg(iocb, sock, msg, len, flags);
+
 	return bt_sock_recvmsg(iocb, sock, msg, len, flags);
 }
 
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

[PATCH v5 0/5] L2CAP updates for FCS, valid PSMs, and stream recv

[Mat Martineau]

These patches incorporate requested fixes from the 'v4' submission.


[PATCH 1/5] Bluetooth: Only enable for L2CAP FCS for ERTM or streaming

This got an "applied" response on the mailing list, but it looks like
the commit got dropped during a rebase.


[PATCH 2/5] Bluetooth: Validate PSM values in calls to connect() and bind()

Fixed comments.


[PATCH 3/5] Bluetooth: Add common code for stream-oriented recvmsg()
[PATCH 4/5] Bluetooth: Use common SOCK_STREAM receive code in RFCOMM
[PATCH 5/5] Bluetooth: Use a stream-oriented recvmsg with SOCK_STREAM L2CAP sockets.

No changes were requested in these patches.


--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

[PATCH 3/5] Bluetooth: Add common code for stream-oriented recvmsg()

[Mat Martineau]

This commit adds a bt_sock_stream_recvmsg() function for use by any
Bluetooth code that uses SOCK_STREAM sockets.  This code is copied
from rfcomm_sock_recvmsg() with minimal modifications to remove
RFCOMM-specific functionality and improve readability.

L2CAP (with the SOCK_STREAM socket type) and RFCOMM have common needs
when it comes to reading data.  Proper stream read semantics require
that applications can read from a stream one byte at a time and not
lose any data.  The RFCOMM code already operated on and pulled data
from the underlying L2CAP socket, so very few changes were required to
make the code more generic for use with non-RFCOMM data over L2CAP.

Applications that need more awareness of L2CAP frame boundaries are
still free to use SOCK_SEQPACKET sockets, and may verify that they
connection did not fall back to basic mode by calling getsockopt().

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 include/net/bluetooth/bluetooth.h |    2 +
 net/bluetooth/af_bluetooth.c      |  109 +++++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+), 0 deletions(-)

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 27a902d..08b6c2a 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -126,6 +126,8 @@ int  bt_sock_unregister(int proto);
 void bt_sock_link(struct bt_sock_list *l, struct sock *s);
 void bt_sock_unlink(struct bt_sock_list *l, struct sock *s);
 int  bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len, int flags);
+int  bt_sock_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
+			struct msghdr *msg, size_t len, int flags);
 uint bt_sock_poll(struct file * file, struct socket *sock, poll_table *wait);
 int  bt_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
 int  bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo);
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 421c45b..77a26fe 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -265,6 +265,115 @@ int bt_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 }
 EXPORT_SYMBOL(bt_sock_recvmsg);
 
+static long bt_sock_data_wait(struct sock *sk, long timeo)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (!skb_queue_empty(&sk->sk_receive_queue))
+			break;
+
+		if (sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN))
+			break;
+
+		if (signal_pending(current) || !timeo)
+			break;
+
+		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		release_sock(sk);
+		timeo = schedule_timeout(timeo);
+		lock_sock(sk);
+		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return timeo;
+}
+
+int bt_sock_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
+			       struct msghdr *msg, size_t size, int flags)
+{
+	struct sock *sk = sock->sk;
+	int err = 0;
+	size_t target, copied = 0;
+	long timeo;
+
+	if (flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	msg->msg_namelen = 0;
+
+	BT_DBG("sk %p size %zu", sk, size);
+
+	lock_sock(sk);
+
+	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
+	timeo  = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+	do {
+		struct sk_buff *skb;
+		int chunk;
+
+		skb = skb_dequeue(&sk->sk_receive_queue);
+		if (!skb) {
+			if (copied >= target)
+				break;
+
+			if ((err = sock_error(sk)) != 0)
+				break;
+			if (sk->sk_shutdown & RCV_SHUTDOWN)
+				break;
+
+			err = -EAGAIN;
+			if (!timeo)
+				break;
+
+			timeo = bt_sock_data_wait(sk, timeo);
+
+			if (signal_pending(current)) {
+				err = sock_intr_errno(timeo);
+				goto out;
+			}
+			continue;
+		}
+
+		chunk = min_t(unsigned int, skb->len, size);
+		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
+			skb_queue_head(&sk->sk_receive_queue, skb);
+			if (!copied)
+				copied = -EFAULT;
+			break;
+		}
+		copied += chunk;
+		size   -= chunk;
+
+		sock_recv_ts_and_drops(msg, sk, skb);
+
+		if (!(flags & MSG_PEEK)) {
+			skb_pull(skb, chunk);
+			if (skb->len) {
+				skb_queue_head(&sk->sk_receive_queue, skb);
+				break;
+			}
+			kfree_skb(skb);
+
+		} else {
+			/* put message back and return */
+			skb_queue_head(&sk->sk_receive_queue, skb);
+			break;
+		}
+	} while (size);
+
+out:
+	release_sock(sk);
+	return copied ? : err;
+}
+EXPORT_SYMBOL(bt_sock_stream_recvmsg);
+
 static inline unsigned int bt_accept_poll(struct sock *parent)
 {
 	struct list_head *p, *n;
-- 
1.7.1

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum