When locking was introduced the error path branch was not taken
into account. Error was found in sparse code checking. Kudos to
Jani Nikula.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@nokia.com>
Acked-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Moving the Ack to before l2cap_retransmit_frame() we can avoid the
case where txWindow is full and the packet can't be retransmited.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

RemoteBusy flag need to be unset before l2cap_ertm_send(), otherwise
l2cap_ertm_send() will return without sending packets because it checks
that flag before start sending.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

For testing purposes it is important to modify the max transmit value.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

SendRRorRNR needs to acknowledge received I-frames (actually every packet
needs to acknowledge received I-frames by sending the proper packet
sequence number), so ReqSeq is set to the next I-frame number sequence to
be pulled by the reassembly function.
SendRRorRNR tells the remote side about local busy conditions, it sends
a Receiver Ready frame if local busy is false or a Receiver Not Ready
if local busy is true.
ReqSeq is the packet's field to send the number of the acknowledged
packets.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
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>

SrejActioned  is a flag that when set prevents local side to retransmit a
I-frame(the data frame) already retransmitted. The local entity can
retransmit again only when it receives a SREJ frame with the F-bit set.
SREJ frame - Selective Reject frame  - is sent when an entity wants the
retransmission of a specific I-frame that was lost or corrupted.
This bug can put ERTM in an unknown state once the entity can't
retransmit.
A frame with the Final bit set is expected when the local side sends a
frame with the Poll bit set due to a local busy condition or a
retransmission timer expired. (Receipt of P-bit shall always be replied by
a frame with the F-bit set).
pi->conn_state keeps informations about many ERTM flags including
SrejActioned.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Fix ERTM's full-duplex channel to work as specified by ERTM spec. ERTM
needs to handle state vars, timers and counters to send and receive
I-frames(the data frames), i.e., for both sides of data communication.
We initialize all of them to the default values here.
Full-duplex channel 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>

Not including net/atm/

Compiled tested x86 allyesconfig only
Added a > 80 column line or two, which I ignored.
Existing checkpatch plaints willfully, cheerfully ignored.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Basic Mode is the default mode of operation of a L2CAP entity. In
this case the RFC (Retransmission and Flow Control) configuration
option should not be used at all.

Normally remote L2CAP implementation should just ignore this option,
but it can cause various side effects with other Bluetooth stacks
that are not capable of handling unknown options.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The default mode for SOCK_SEQPACKET is Basic Mode. So when no
mode has been specified, Basic Mode shall be used.

This is important for current application to keep working as
expected and not cause a regression.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Before calling capable(CAP_NET_RAW) check if this operations is on behalf
of the kernel or on behalf of userspace.  Do not do the security check if
it is on behalf of the kernel.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The generic __sock_create function has a kern argument which allows the
security system to make decisions based on if a socket is being created by
the kernel or by userspace.  This patch passes that flag to the
net_proto_family specific create function, so it can do the same thing.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When shutdown ppp connection, lockdep waring about non-static key
will happen, it is caused by the lock is not initialized properly
at that time.

Fix with tuning the lock/skb_queue_head init order

[   94.339261] INFO: trying to register non-static key.
[   94.342509] the code is fine but needs lockdep annotation.
[   94.342509] turning off the locking correctness validator.
[   94.342509] Pid: 0, comm: swapper Not tainted 2.6.31-mm1 #2
[   94.342509] Call Trace:
[   94.342509]  [<c0248fbe>] register_lock_class+0x58/0x241
[   94.342509]  [<c024b5df>] ? __lock_acquire+0xb57/0xb73
[   94.342509]  [<c024ab34>] __lock_acquire+0xac/0xb73
[   94.342509]  [<c024b7fa>] ? lock_release_non_nested+0x17b/0x1de
[   94.342509]  [<c024b662>] lock_acquire+0x67/0x84
[   94.342509]  [<c04cd1eb>] ? skb_dequeue+0x15/0x41
[   94.342509]  [<c054a857>] _spin_lock_irqsave+0x2f/0x3f
[   94.342509]  [<c04cd1eb>] ? skb_dequeue+0x15/0x41
[   94.342509]  [<c04cd1eb>] skb_dequeue+0x15/0x41
[   94.342509]  [<c054a648>] ? _read_unlock+0x1d/0x20
[   94.342509]  [<c04cd641>] skb_queue_purge+0x14/0x1b
[   94.342509]  [<fab94fdc>] l2cap_recv_frame+0xea1/0x115a [l2cap]
[   94.342509]  [<c024b5df>] ? __lock_acquire+0xb57/0xb73
[   94.342509]  [<c0249c04>] ? mark_lock+0x1e/0x1c7
[   94.342509]  [<f8364963>] ? hci_rx_task+0xd2/0x1bc [bluetooth]
[   94.342509]  [<fab95346>] l2cap_recv_acldata+0xb1/0x1c6 [l2cap]
[   94.342509]  [<f8364997>] hci_rx_task+0x106/0x1bc [bluetooth]
[   94.342509]  [<fab95295>] ? l2cap_recv_acldata+0x0/0x1c6 [l2cap]
[   94.342509]  [<c02302c4>] tasklet_action+0x69/0xc1
[   94.342509]  [<c022fbef>] __do_softirq+0x94/0x11e
[   94.342509]  [<c022fcaf>] do_softirq+0x36/0x5a
[   94.342509]  [<c022fe14>] irq_exit+0x35/0x68
[   94.342509]  [<c0204ced>] do_IRQ+0x72/0x89
[   94.342509]  [<c02038ee>] common_interrupt+0x2e/0x34
[   94.342509]  [<c024007b>] ? pm_qos_add_requirement+0x63/0x9d
[   94.342509]  [<c038e8a5>] ? acpi_idle_enter_bm+0x209/0x238
[   94.342509]  [<c049d238>] cpuidle_idle_call+0x5c/0x94
[   94.342509]  [<c02023f8>] cpu_idle+0x4e/0x6f
[   94.342509]  [<c0534153>] rest_init+0x53/0x55
[   94.342509]  [<c0781894>] start_kernel+0x2f0/0x2f5
[   94.342509]  [<c0781091>] i386_start_kernel+0x91/0x96
Reported-by: NOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Tested-by: NOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All usages of structure net_proto_ops should be declared const.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This provides safety against negative optlen at the type
level instead of depending upon (sometimes non-trivial)
checks against this sprinkled all over the the place, in
each and every implementation.

Based upon work done by Arjan van de Ven and feedback
from Linus Torvalds.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When called, 'Send RRorRNR' should send a RNR frame if local device is
busy or a RR frame otherwise.
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>

Implement the Recv ReqSeqAndFBit event when a RR frame with F bit set is
received.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Simplify more conversions to the right endian with the proper helpers.
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Avoid race conditions when accessing the L2CAP socket from within the
timeout handlers.
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>

Streaming Mode is helpful for the Bluetooth streaming based profiles, such
as A2DP. It doesn't have any error control or flow control.
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>

The code for sending a disconnect request was repeated several times
within L2CAP source code. So move this into its own function.
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>

When trying to establish a connection with Enhanced Retransmission mode
enabled, the RFC option needs to be added to the configuration.
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>

Since the Enhanced Retransmission mode for L2CAP is still under heavy
development disable it by default and provide a module option to enable
it manually for testing.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The Bluetooth source uses some endian conversion helpers, that in the end
translate to kernel standard routines. So remove this obfuscation since it
is fully pointless.
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>

This patch fixes the errors without changing the l2cap.o binary:

 text    data     bss     dec     hex filename
18059     568       0   18627    48c3 l2cap.o.after
18059     568       0   18627    48c3 l2cap.o.before
Signed-off-by: NGustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The initial value of err is not used until it is set to -ENOMEM. So just
remove the initialization completely.

Based on a patch from Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
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>