6lowpan: introduce lowpan_push_hc_data function

This patch introduce the lowpan_push_hc_data function to set data in
the iphc buffer.

It's a common case to set data and increase the buffer pointer. This
helper function can be used many times in header_compress function to
generate the iphc header.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: udp use lowpan_push_hc_data function

This patch uses the lowpan_push_hc_data to generate iphc header.

The current implementation has some wrong pointer arithmetic issues and
works in a random case only.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: fix udp compress ordering

In case ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) the order of
uncompression is wrong. It's always first source port then destination
port as second.

See:
http://tools.ietf.org/html/rfc6282#section-4.3.3

"Fields carried in-line (in part or in whole) appear in the same order
as they do in the UDP header format"

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: fix udp byte ordering

The incoming udp header in lowpan_compress_udp_header function is
already in network byte order.

Everytime we read this values for source and destination port we need
to convert this value to host byte order.

In the outcoming header we need to set this value in network byte order
which the upcoming process assumes.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: add udp warning for elided checksum

Bit 5 of "UDP LOWPAN_NHC Format" indicate that the checksum can be
elided.
The host need to calculate the udp checksum afterwards but this isn't
supported right now.

See:
http://tools.ietf.org/html/rfc6282#section-4.3.3
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: udp use lowpan_fetch_skb function

Cleanup the lowpan_uncompress_udp_header function to use the
lowpan_fetch_skb function.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: udp use subtraction on both conditions

Cleanup code to handle both calculation in the same way.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
6lowpan: cleanup udp compress function

This patch remove unnecessary casts and brackets in compress_udp_header
function.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Bluetooth: Save connection interval parameters in hci_conn

This patch creates two new fields in struct hci_conn to save the
minimum and maximum connection interval values used to establish
the connection this object represents.

This change is required in order to know what parameters the
connection is currently using.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Group list_head fields from strcut hci_dev together

This patch groups the list_head fields from struct hci_dev together
and removes empty lines between them.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce connection parameters list

This patch adds to hdev the connection parameters list (hdev->le_
conn_params). The elements from this list (struct hci_conn_params)
contains the connection parameters (for now, minimum and maximum
connection interval) that should be used during the connection
establishment.

The struct hci_conn_params also defines the 'auto_connect' field
which will be used to implement the auto connection mechanism.

Moreover, this patch adds helper functions to manipulate hdev->le_
conn_params list. Some of these functions are also declared in
hci_core.h since they will be used outside hci_core.c in upcoming
patches.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Use connection parameters if any

This patch changes hci_connect_le() so it uses the connection
parameters specified for the certain device. If no parameters
were configured, we use the default values.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce fail_conn_attempt() helper

This patch moves connection attempt failure code to its own function
so it can be reused in the next patch.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Stop scanning on LE connection

Some LE controllers don't support scanning and creating a connection
at the same time. So we should always stop scanning in order to
establish the connection.

Since we may prematurely stop the discovery procedure in favor of
the connection establishment, we should also cancel hdev->le_scan_
disable delayed work and set the discovery state to DISCOVERY_STOPPED.

This change does a small improvement since it is not mandatory the
user stops scanning before connecting anymore. Moreover, this change
is required by upcoming LE auto connection mechanism in order to work
properly with controllers that don't support background scanning and
connection establishment at the same time.

In future, we might want to do a small optimization by checking if
controller is able to scan and connect at the same time. For now,
we want the simplest approach so we always stop scanning (even if
the controller is able to carry out both operations).

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Remove unused function

This patch removes hci_create_le_conn() since it is not used anymore.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce hdev->pend_le_conn list

This patch introduces the hdev->pend_le_conn list which holds the
device addresses the kernel should autonomously connect. It also
introduces some helper functions to manipulate the list.

The list and helper functions will be used by the next patch which
implements the LE auto connection infrastructure.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Introduce LE auto connection infrastructure

This patch introduces the LE auto connection infrastructure.
This infrastructure will be used to implement the auto_connect
options from hci_conn_params.

In summary, the auto connection mechanism works as follows: Once the
first pending LE connection is created, the background scanning is
started. When the target device is found in range, the kernel
autonomously starts the connection attempt. If connection is
established successfully, that pending LE connection is deleted and
the background is stopped.

To achieve that, this patch introduces the hci_update_background_scan()
which controls the background scanning state. This function starts or
stops the background scanning based on the hdev->pend_le_conns list. If
there is no pending LE connection, the background scanning is stopped.
Otherwise, we start the background scanning.

Then, every time a pending LE connection is added we call hci_update_
background_scan() so the background scanning is started (in case it is
not already running). Likewise, every time a pending LE connection is
deleted we call hci_update_background_scan() so the background scanning
is stopped (in case this was the last pending LE connection) or it is
started again (in case we have more pending LE connections). This way
the background scanning keeps running until all pending LE connection
are established.

When a device with pending connection is in range, we establish the
connection and delete the pending connection.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Re-enable background scan in case of error

Since we temporarily stop the background scanning in favor of
connection, we should re-enable it in case something goes wrong
with connection establishment. So this patch adds a hci_update_
background_scan() call in fail_conn_attempt() and hci_le_conn_
complete_evt() error flow.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Temporarily stop background scanning on discovery

If the user send a mgmt start discovery command while the background
scanning is running, we should temporarily stop it. Once the discovery
finishes, we start the background scanning again.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Bluetooth: Auto connection and power on

When hdev is closed (e.g. Mgmt power off command, RFKILL or controller
is reset), the ongoing active connections are silently dropped by the
controller (no Disconnection Complete Event is sent to host). For that
reason, the devices that require HCI_AUTO_CONN_ALWAYS are not added to
hdev->pend_le_conns list and they won't auto connect.

So to fix this issue, during hdev closing, we remove all pending LE
connections. After adapter is powered on, we add a pending LE connection
for each HCI_AUTO_CONN_ALWAYS address.

This way, the auto connection mechanism works propely after a power
off and power on sequence as well as RFKILL block/unblock.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>