This change addresses an L2CAP ERTM throughput problem when a remote
device does not fully utilize the available transmit window.

The L2CAP ERTM transmit window size determines the maximum number of
unacked frames that may be outstanding at any time. It is configured
separately for each direction of an ERTM connection. Each side sends a
configuration request with a tx_win field indicating how many unacked
frames it is capable of receiving before sending an ack. The
configuration response's tx_win field shows how many frames the
transmitter will actually send before waiting for an ack.

It's important to trace both the actual transmit window (to check for
validity of incoming frames) and the number of frames that the
transmitter will send before waiting (to send acks at the appropriate
time). Now there are separate tx_win and ack_win values. ack_win is
updated based on configuration responses, and is used to determine
when acks are sent.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Improve debug output.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

A2MP doesn't use part of the L2CAP chan ops API so we just create general
empty function instead of the A2MP specific one.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This patch renames L2CAP_LE_DEFAULT_MTU macro to L2CAP_LE_MIN_MTU
since it represents the minimum MTU value, not the default MTU
value for LE.
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

A2MP fixed channel do not have sk
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Create and initialize fixed A2MP channel
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This move socket specific code to l2cap_sock.c.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This remove a bit more of socket code from l2cap core, this calls set the
SOCK_ZAPPED and do some clean up depending on the socket state.
Reported-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Use chan instead of void * makes more sense here.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Define assigned Protocol and Service Multiplexor (PSM) identifiers
and use them instead of magic numbers.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Define Continuation flag which the only flag used from Flags field
in L2CAP Configuration Request and Response.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now that l2cap_ctrl is used to set up control fields, these macros are
not needed.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The ERTM specification requires the retransmit timer to be cancelled
when the monitor timer is set.  The retransmit timer cannot be set
again while the monitor timer is pending.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This deletes the receive code that had handlers for each frame type at
the top level, and then had logic to determine the receive state
within each handler.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This fixes a regression from commit
2ead70b8 that is present in all
kernels starting at v3.0.

When L2CAP information was moved to struct l2cap_chan, a check was
added to l2cap_chan_del to avoid certain cleanup operations when ERTM
or streaming mode had not yet been initialized.  The logic in the
check did not take in to account that chan->conf_state is set to 0 in
l2cap_chan_ready, so l2cap_chan_del failed to cancel timers and leaked
memory any time the ERTM queues or lists were not empty.

This change makes sure that l2cap_chan_del only returns early if
ERTM initialization was not performed.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Use more common code for ERTM and streaming mode segmentation and
transmission, and begin using skb control block data for delaying
extended or enhanced header generation until just before the packet is
transmitted.  This code is also better suited for resegmentation,
which is needed when L2CAP links are reconfigured after an AMP channel
move.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Reviewed-by: NUlisses Furquim <ulisses@profusion.mobi>
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

Instead of using modular division, the offset can be calculated using
only addition and subtraction.  The previous calculation did not work
as intended and was more difficult to understand, involving unsigned
integer underflow and a check for a negative value where one was not
possible.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

In order to establish a LE connection we need the address type
information. User-space already pass this information to kernel
through struct sockaddr_l2.

This patch adds the dst_type parameter to l2cap_chan_connect so we
are able to pass the address type info from user-space down to
hci_conn layer.
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds the address type info to struct sockaddr_l2 so
user-space can inform the remote device address type required
to establish LE connections.

Soon, instead of looking the advertising cache up to discover the
address type, we'll use this address type info to establish LE
connections.
Signed-off-by: NAndre Guedes <andre.guedes@openbossa.org>
Acked-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

A sequence list is a data structure used to track frames that need to
be retransmitted, and frames that have been requested for
retransmission by the remote device.  It can compactly represent a
list of sequence numbers within the ERTM transmit window.  Memory for
the list is allocated once at connection time, and common operations
in ERTM are O(1).
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Use ERR_PTR maginc instead.
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Some parameters in L2CAP chan are set to default similar way in
socket based channels and A2MP channels. Adds common function which
sets all defaults.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

Following the separation if core and sock code this change avoid
manipulation of sk inside l2cap_chan_create().
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

Adds some missing values for control field parsing, additional data
for the new state machine, and enumerations for states, incoming
packet classification, and state machine events.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

Add comments to timer implementation and style fixes.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo@padovan.org>

Proper align the struct definitions.
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

The L2CAP timeout constants are always used in form of jiffies. So just
include the conversion from msecs in the define itself. This has the
advantage of making the code where the timeout is used more readable.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Fixed channel mask needs to be stored to decide whether to
use A2MP for example. So far save only one relevant byte which
keeps all information we need.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Channel lock will be used to lock L2CAP channels which are locked
currently by socket locks.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NGustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Use state_to_string function in debug statements.
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

__cancel_delayed_work() is being used in some paths where we cannot
sleep waiting for the delayed work to finish. However, that function
might return while the timer is running and the work will be queued
again. Replace the calls with safer cancel_delayed_work() version
which spins until the timer handler finishes on other CPUs and
cancels the delayed work.
Signed-off-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

After moving L2CAP timers to workqueues l2cap_set_timer expects timeout
value to be specified in jiffies but constants defined in miliseconds
are used. This makes timeouts unreliable when CONFIG_HZ is not set to
1000.

__set_chan_timer macro still uses jiffies as input to avoid multiple
conversions from/to jiffies for sk_sndtimeo value which is already
specified in jiffies.
Signed-off-by: NAndrzej Kaczmarek <andrzej.kaczmarek@tieto.com>
Ackec-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

As reported by Dan Carpenter this function causes a Sparse warning and
shouldn't be declared inline:

include/net/bluetooth/l2cap.h:837:30 error: marked inline, but without a
definition"
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

__cancel_delayed_work() is being used in some paths where we cannot
sleep waiting for the delayed work to finish. However, that function
might return while the timer is running and the work will be queued
again. Replace the calls with safer cancel_delayed_work() version
which spins until the timer handler finishes on other CPUs and
cancels the delayed work.
Signed-off-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Add channel-specific skb allocation method
Signed-off-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

This is usefull when need to make action after timer was cleared
depending on if it was running or not.
Signed-off-by: NSzymon Janc <szymon.janc@tieto.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

As reported by Dan Carpenter this function causes a Sparse warning and
shouldn't be declared inline:

include/net/bluetooth/l2cap.h:837:30 error: marked inline, but without a
definition"
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>

After moving L2CAP timers to workqueues l2cap_set_timer expects timeout
value to be specified in jiffies but constants defined in miliseconds
are used. This makes timeouts unreliable when CONFIG_HZ is not set to
1000.

__set_chan_timer macro still uses jiffies as input to avoid multiple
conversions from/to jiffies for sk_sndtimeo value which is already
specified in jiffies.
Signed-off-by: NAndrzej Kaczmarek <andrzej.kaczmarek@tieto.com>
Ackec-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

When cancelling a delayed work (timer) in L2CAP we can not sleep holding
the sock mutex otherwise we might deadlock with an L2CAP timer handler.
This is possible because RX/TX and L2CAP timers run in different workqueues.
The scenario below illustrates the problem. Thus we are now avoiding to
sleep on the timers locks.

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.1.0-05270-ga978dc7-dirty #239
 -------------------------------------------------------
 kworker/1:1/873 is trying to acquire lock:
  (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}, at: [<ffffffffa002ceac>] l2cap_chan_timeout+0x3c/0xe0 [bluetooth]

 but task is already holding lock:
  ((&(&chan->chan_timer)->work)){+.+...}, at: [<ffffffff81051a86>] process_one_work+0x126/0x450

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 ((&(&chan->chan_timer)->work)){+.+...}:
        [<ffffffff8106b276>] check_prevs_add+0xf6/0x170
        [<ffffffff8106b903>] validate_chain+0x613/0x790
        [<ffffffff8106dfee>] __lock_acquire+0x4be/0xac0
        [<ffffffff8106ec2d>] lock_acquire+0x8d/0xb0
        [<ffffffff81052a6f>] wait_on_work+0x4f/0x160
        [<ffffffff81052ca3>] __cancel_work_timer+0x73/0x80
        [<ffffffff81052cbd>] cancel_delayed_work_sync+0xd/0x10
        [<ffffffffa002f2ed>] l2cap_chan_connect+0x22d/0x470 [bluetooth]
        [<ffffffffa002fb51>] l2cap_sock_connect+0xb1/0x140 [bluetooth]
        [<ffffffff8130811b>] kernel_connect+0xb/0x10
        [<ffffffffa00cf98a>] rfcomm_session_create+0x12a/0x1c0 [rfcomm]
        [<ffffffffa00cfbe7>] __rfcomm_dlc_open+0x1c7/0x240 [rfcomm]
        [<ffffffffa00d07c2>] rfcomm_dlc_open+0x42/0x70 [rfcomm]
        [<ffffffffa00d3b03>] rfcomm_sock_connect+0x103/0x150 [rfcomm]
        [<ffffffff8130bd7e>] sys_connect+0xae/0xc0
        [<ffffffff813368d2>] compat_sys_socketcall+0xb2/0x220
        [<ffffffff813b2089>] sysenter_dispatch+0x7/0x30

 -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}:
        [<ffffffff8106b16d>] check_prev_add+0x6cd/0x6e0
        [<ffffffff8106b276>] check_prevs_add+0xf6/0x170
        [<ffffffff8106b903>] validate_chain+0x613/0x790
        [<ffffffff8106dfee>] __lock_acquire+0x4be/0xac0
        [<ffffffff8106ec2d>] lock_acquire+0x8d/0xb0
        [<ffffffff8130d91a>] lock_sock_nested+0x8a/0xa0
        [<ffffffffa002ceac>] l2cap_chan_timeout+0x3c/0xe0 [bluetooth]
        [<ffffffff81051ae4>] process_one_work+0x184/0x450
        [<ffffffff8105276e>] worker_thread+0x15e/0x340
        [<ffffffff81057bb6>] kthread+0x96/0xa0
        [<ffffffff813b1ef4>] kernel_thread_helper+0x4/0x10

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock((&(&chan->chan_timer)->work));
                                lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
                                lock((&(&chan->chan_timer)->work));
   lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);

  *** DEADLOCK ***

 2 locks held by kworker/1:1/873:
  #0:  (events){.+.+.+}, at: [<ffffffff81051a86>] process_one_work+0x126/0x450
  #1:  ((&(&chan->chan_timer)->work)){+.+...}, at: [<ffffffff81051a86>] process_one_work+0x126/0x450

 stack backtrace:
 Pid: 873, comm: kworker/1:1 Not tainted 3.1.0-05270-ga978dc7-dirty #239
 Call Trace:
  [<ffffffff813a0f6e>] print_circular_bug+0xd2/0xe3
  [<ffffffff8106b16d>] check_prev_add+0x6cd/0x6e0
  [<ffffffff8106b276>] check_prevs_add+0xf6/0x170
  [<ffffffff8106b903>] validate_chain+0x613/0x790
  [<ffffffff8106dfee>] __lock_acquire+0x4be/0xac0
  [<ffffffff8130d8f6>] ? lock_sock_nested+0x66/0xa0
  [<ffffffff8106ea30>] ? lock_release_nested+0x100/0x110
  [<ffffffff8130d8f6>] ? lock_sock_nested+0x66/0xa0
  [<ffffffff8106ec2d>] lock_acquire+0x8d/0xb0
  [<ffffffffa002ceac>] ? l2cap_chan_timeout+0x3c/0xe0 [bluetooth]
  [<ffffffff8130d91a>] lock_sock_nested+0x8a/0xa0
  [<ffffffffa002ceac>] ? l2cap_chan_timeout+0x3c/0xe0 [bluetooth]
  [<ffffffff81051a86>] ? process_one_work+0x126/0x450
  [<ffffffffa002ceac>] l2cap_chan_timeout+0x3c/0xe0 [bluetooth]
  [<ffffffff81051ae4>] process_one_work+0x184/0x450
  [<ffffffff81051a86>] ? process_one_work+0x126/0x450
  [<ffffffffa002ce70>] ? l2cap_security_cfm+0x4e0/0x4e0 [bluetooth]
  [<ffffffff8105276e>] worker_thread+0x15e/0x340
  [<ffffffff81052610>] ? manage_workers+0x110/0x110
  [<ffffffff81057bb6>] kthread+0x96/0xa0
  [<ffffffff813b1ef4>] kernel_thread_helper+0x4/0x10
  [<ffffffff813af69d>] ? retint_restore_args+0xe/0xe
  [<ffffffff81057b20>] ? __init_kthread_worker+0x70/0x70
  [<ffffffff813b1ef0>] ? gs_change+0xb/0xb
Signed-off-by: NUlisses Furquim <ulisses@profusion.mobi>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>