Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

First step to move all l2cap_sock_ops function to l2cap_sock.c
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

This patch tries to do the minimal to move l2cap_sock_create() and its
dependencies to l2cap_sock.c. It create a API to initialize and cleanup
the L2CAP sockets from l2cap_core.c through l2cap_init_sockets() and
l2cap_cleanup_sockets().
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Modification of Nick Pelly <npelly@google.com> patch.

With Bluetooth 2.1 ACL packets can be flushable or non-flushable. This commit
makes ACL data packets non-flushable by default on compatible chipsets, and
adds the BT_FLUSHABLE socket option to explicitly request flushable ACL
data packets for a given L2CAP socket. This is useful for A2DP data which can
be safely discarded if it can not be delivered within a short time (while
other ACL data should not be discarded).

Note that making ACL data flushable has no effect unless the automatic flush
timeout for that ACL link is changed from its default of 0 (infinite).

Default packet types (for compatible chipsets):
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
    .... 0000 0000 0010 = Connection Handle: 0x0002
    ..00 .... .... .... = PB Flag: First Non-automatically Flushable Packet (0)
    00.. .... .... .... = BC Flag: Point-To-Point (0)
    Data Total Length: 8
Bluetooth L2CAP Packet

After setting BT_FLUSHABLE
(sock.setsockopt(274 /*SOL_BLUETOOTH*/, 8 /* BT_FLUSHABLE */, 1 /* flush */))
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
    .... 0000 0000 0010 = Connection Handle: 0x0002
    ..10 .... .... .... = PB Flag: First Automatically Flushable Packet (2)
    00.. .... .... .... = BC Flag: Point-To-Point (0)
    Data Total Length: 8
Bluetooth L2CAP Packet
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@nokia.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Remove extra spaces from legal text so that legal stuff looks
the same for all bluetooth code.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@nokia.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Do not initialize static vars to zero, macros with complex values
shall be enclosed with (), remove unneeded braces.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@nokia.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

Change "return (EXPR);" to "return EXPR;"

return is not a function, parentheses are not required.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The previous value of 672 for L2CAP_DEFAULT_MAX_PDU_SIZE is based on
the default L2CAP MTU.  That default MTU is calculated from the size
of two DH5 packets, minus ACL and L2CAP b-frame header overhead.

ERTM is used with newer basebands that typically support larger 3-DH5
packets, and i-frames and s-frames have more header overhead.  With
clean RF conditions, basebands will typically attempt to use 1021-byte
3-DH5 packets for maximum throughput.  Adjusting for 2 bytes of ACL
headers plus 10 bytes of worst-case L2CAP headers yields 1009 bytes
of payload.

This PDU size imposes less overhead for header bytes and gives the
baseband the option to choose 3-DH5 packets, but is small enough for
ERTM traffic to interleave well with other L2CAP or SCO data.
672-byte payloads do not allow the most efficient over-the-air
packet choice, and cannot achieve maximum throughput over BR/EDR.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The L2CAP specification requires that the ERTM retransmit timeout be at
least 2 seconds for BR/EDR connections.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

To make net/ and include/net/ code consistent use __packed instead of
__attribute__ ((packed)). Bluetooth subsystem was one of the last net
subsys still using __attribute__ ((packed)).
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Copyright for the time I worked on L2CAP during the Google Summer of Code
program.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Using a lock to deal with the ERTM race condition - interruption with
new data from the hci layer - is wrong. We should use the native skb
backlog queue.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When mode is mandatory we shall not send connect request and report this
to the userspace as well.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

l2cap_ertm_send() can be called both from user context and bottom half
context. The socket locks for that contexts are different, the user
context uses a mutex(which can sleep) and the second one uses a
spinlock_bh. That creates a race condition when we have interruptions on
both contexts at the same time.

The better way to solve this is to add a new spinlock to lock
l2cap_ertm_send() and the vars it access. The other solution was to defer
l2cap_ertm_send() with a workqueue, but we the sending process already
has one defer on the hci layer. It's not a good idea add another one.

The patch refactor the code to create l2cap_retransmit_frames(), then we
encapulate the lock of l2cap_ertm_send() for some call. It also changes
l2cap_retransmit_frame() to l2cap_retransmit_one_frame() to avoid
confusion
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Supports Local Busy condition handling through a waitqueue that wake ups
each 200ms and try to push the packets to the upper layer. If it can
push all the queue then it leaves the Local Busy state.

The patch modifies the behaviour of l2cap_ertm_reassembly_sdu() to
support retry of the push operation.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

With the sockopt extension we can set a per-channel MaxTx value.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now that we can set the txWindow we need to change the acknowledgement
procedure to ack after each (pi->txWindow/6 + 1). The plus 1 is to avoid
the zero value.
It also renames pi->num_to_ack to a better name: pi->num_acked.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now we can set/get Transmission Window size via sockopt.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

We were accepting values bigger than we can accept. This was leading
ERTM to drop packets because of wrong FCS checks.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

We ack I-frames on each txWindow/5 I-frames received, but if the sender
stop to send I-frames and it's not a txWindow multiple we can leave some
frames unacked.
So I added a timer to ack I-frames on this case. The timer expires in
200ms.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

After receive a RR with P bit set ERTM shall use this funcion to choose
what type of frame to reply with F bit = 1.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: NJoão Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

RejActioned is used to prevent retransmission when a entity is on the
WAIT_F state, i.e., waiting for a frame with F-bit set due local busy
condition or a expired retransmission timer. (When these two events raise
they send a frame with the Poll bit set and enters in the WAIT_F state to
wait for a frame with the Final bit set.)
The local entity doesn't send I-frames(the data frames) until the receipt
of a frame with F-bit set. When that happens it also set RejActioned to false.
RejActioned is a mandatory feature of ERTM spec.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

As specified by ERTM spec an ERTM channel can acknowledge received
I-frames(the data frames) by sending an I-frame with the proper ReqSeq
value (i.e. ReqSeq is set to BufferSeq).  Until now we aren't setting the
ReqSeq value on I-frame control bits. That way we can save sending
S-frames(Supervise frames) only to acknowledge receipt of I-frames. It
is very helpful to the full-duplex channel.
ReqSeq is the packet sequence number sent in an acknowledgement frame to
acknowledge receipt of frames up to (ReqSeq - 1).
BufferSeq controls the receiver buffer, it is used to delay
acknowledgement of new frames to not cause buffer overflow. BufferSeq
value is not increased until frames are pulled by reassembly function.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Implement all issues related to RemoteBusy in the RECV state table.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Support for receiving of SREJ frames as specified by the state table.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When L2CAP loses an I-frame we send a SREJ frame to the transmitter side
requesting the lost packet. This patch implement all Recv I-frame events
on SREJ_SENT state table except the ones that deal with SendRej (the REJ
exception at receiver side is yet not implemented).
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Implement CRC16 check for L2CAP packets. FCS is used by Streaming Mode and
Enhanced Retransmission Mode and is a extra check for the packet content.

Using CRC16 is the default, L2CAP won't use FCS only when both side send
a "No FCS" request.

Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com>
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

L2CAP uses retransmission and monitor timers to inquiry the other side
about unacked I-frames. After sending each I-frame we (re)start the
retransmission timer. If it expires, we start a monitor timer that send a
S-frame with P bit set and wait for S-frame with F bit set. If monitor
timer expires, try again, at a maximum of L2CAP_DEFAULT_MAX_TX.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When receiving an I-frame with unexpected txSeq, receiver side start the
recovery procedure by sending a REJ S-frame to the transmitter side. So
the transmitter can re-send the lost I-frame.

This patch just adds a basic support for retransmission, it doesn't
mean that ERTM now has full support for packet retransmission.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

ERTM should use Segmentation and Reassembly to break down a SDU in many
PDUs on sending data to the other side.

On sending packets we queue all 'segments' until end of segmentation and
just the add them to the queue for sending. On receiving we create a new
SKB with the SDU reassembled.

Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com>
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds support for ERTM transfers, without retransmission, with
txWindow up to 63 and with acknowledgement of packets received. Now the
packets are queued before call l2cap_do_send(), so packets couldn't be
sent at the time we call l2cap_sock_sendmsg(). They will be sent in
an asynchronous way on later calls of l2cap_ertm_send(). Besides if an
error occurs on calling l2cap_do_send() we disconnect the channel.

Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com>
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Add support to config_req and config_rsp to configure ERTM and Streaming
mode. If the remote device specifies ERTM or Streaming mode, then the
same mode is proposed. Otherwise ERTM or Basic mode is used. And in case
of a state 2 device, the remote device should propose the same mode. If
not, then the channel gets disconnected.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

To enable Enhanced Retransmission mode it needs to be set via a socket
option. A different mode can be set on a socket, but on listen() and
connect() the mode is checked and ERTM is only allowed if it is enabled
via the module parameter.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This adds the basic constants required to add support for L2CAP Enhanced
Retransmission feature.

Based on a patch from Nathan Holstein <nathan@lampreynetworks.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Using the L2CAP_CONF_HINT macro is easier to understand than using a
hardcoded 0x80 value.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Use macros instead of hardcoded numbers to make the L2CAP source code
more readable.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>