Updated: 2022/Sep/29
Please read Privacy Policy. It's for your privacy.
BLUETOOTH(4) Device Drivers Manual BLUETOOTH(4)
NAME
bluetooth - Bluetooth Protocol Family
SYNOPSIS
#include <netbt/bluetooth.h>
#include <netbt/hci.h>
#include <netbt/l2cap.h>
#include <netbt/rfcomm.h>
DESCRIPTION
The Bluetooth Protocol Family
ADDRESSING
Bluetooth Protocol Family sockets all use a sockaddr_bt structure which
contains a Bluetooth Device Address (BDADDR). This consists of a six
byte string in least significant byte first order.
struct sockaddr_bt {
uint8_t bt_len;
sa_family_t bt_family;
bdaddr_t bt_bdaddr;
uint16_t bt_psm;
uint8_t bt_channel;
};
The local address used by the socket can be set with bind(2).
PROTOCOLS
Protocols included are:
BTPROTO_HCI
This gives raw access to the Host Controller Interface of local
devices using the HCI protocol as described in the Bluetooth Core
Specification. Any user may open an HCI socket but there are
limitations on what unprivileged users can send and receive. The
local address specified by bind(2) may be used to select the device
that the socket will receive packets from. If BDADDR_ANY is
specified then the socket will receive packets from all devices on
the system. connect(2) may be used to create connections such that
packets sent with send(2) will be delivered to the specified device,
otherwise sendto(2) should be used.
The bt_psm and bt_channel fields in the sockaddr_bt structure are
ignored by HCI protocol code and should be set to zero.
HCI socket options:
SO_HCI_EVT_FILTER [struct hci_filter]
This filter controls which events will be received at the socket.
See <netbt/hci.h> for available events. By default,
Command_Complete and Command_Status events only are enabled.
SO_HCI_PKT_FILTER [struct hci_filter]
This filter controls the type of packets that will be received at
the socket. By default, Event packets only are enabled.
SO_HCI_DIRECTION [int]
When set, this enables control messages on packets received at
the socket indicating the direction of travel of the packet.
HCI sysctl(8) controls:
net.bluetooth.hci.sendspace
Default send buffer size for HCI sockets.
net.bluetooth.hci.recvspace
Default receive buffer size for HCI sockets
net.bluetooth.hci.acl_expiry
If set, this is the time in seconds after which unused ACL data
connections will be expired. If zero, connections will not be
closed.
net.bluetooth.hci.memo_expiry
Time, in seconds, that the system will keep records of Bluetooth
devices in the vicinity after an Inquiry Response packet has
been received. This information is used for routing purposes.
net.bluetooth.hci.eventq_max
The maximum number of packets on the low level Event queue.
net.bluetooth.hci.aclrxq_max
The maximum number of packets on the low level ACL queue.
net.bluetooth.hci.scorxq_max
The maximum number of packets on the low level SCO queue.
BTPROTO_L2CAP
L2CAP sockets give sequential packet access over channels to other
Bluetooth devices and make use of the bt_psm field in the sockaddr_bt
structure to select the Protocol/Service Multiplexer to specify when
making connections. If the special value of L2CAP_PSM_ANY is bound
when the listen(2) call is made, the next available PSM from the
dynamic range above 0x1001 will be selected and may be discovered
using the getsockname(2) call.
L2CAP socket options:
SO_L2CAP_IMTU [uint16_t]
Incoming MTU
SO_L2CAP_OMTU [uint16_t]
Outgoing MTU (read-only)
SO_L2CAP_LM [int]
Link Mode. The following bits may be set:
L2CAP_LM_AUTH Request authentication (pairing).
L2CAP_LM_ENCRYPT Request encryption (includes auth).
L2CAP_LM_SECURE Request secured link (encryption, plus
change link key).
Link mode settings will be applied to the baseband link during
L2CAP connection establishment. If the L2CAP connection is
already established, EINPROGRESS may be returned, and it is not
possible to guarantee that data already queued (from either end)
will not be delivered. If the mode change fails, the L2CAP
connection will be aborted.
L2CAP sysctl(8) controls:
net.bluetooth.l2cap.sendspace
Default send buffer size for L2CAP sockets.
net.bluetooth.l2cap.recvspace
Default receive buffer size for L2CAP sockets.
net.bluetooth.l2cap.rtx
Response Timeout eXpiry for L2CAP signals.
net.bluetooth.l2cap.ertx
Extended Response Timeout eXpiry for L2CAP signals.
BTPROTO_RFCOMM
RFCOMM sockets provide streamed data over Bluetooth connection and
make use of the bt_psm, and bt_channel fields in the sockaddr_bt
structure. The channel number must be between 1 and 30 inclusive
except that if the special value RFCOMM_CHANNEL_ANY is bound, when
the listen(2) call is made, the first unused channel for the relevant
bdaddr will be allocated and may be discovered using the
getsockname(2) call. If no PSM is specified, a default value of
L2CAP_PSM_RFCOMM (0x0003) will be used.
RFCOMM socket options:
SO_RFCOMM_MTU [uint16_t]
Maximum Frame Size to use for this link.
SO_RFCOMM_LM [int]
Link Mode. The following bits may be set at any time:
RFCOMM_LM_AUTH Request authentication (pairing).
RFCOMM_LM_ENCRYPT Request encryption (includes auth).
RFCOMM_LM_SECURE Request secured link (encryption, plus
change link key).
Link mode settings will be applied to the baseband link during
RFCOMM connection establishment. If the RFCOMM connection is
already established, EINPROGRESS may be returned, and it is not
possible to guarantee that data already queued (from either end)
will not be delivered. If the mode change fails, the RFCOMM
connection will be aborted.
RFCOMM sysctl(8) controls:
net.bluetooth.rfcomm.sendspace
Default send buffer size for RFCOMM sockets.
net.bluetooth.rfcomm.recvspace
Default receive buffer size for RFCOMM sockets.
net.bluetooth.rfcomm.default_mtu
Maximum Frame Size (N1)
net.bluetooth.ack_timeout
Acknowledgement Timer (T1)
net.bluetooth.mcc_timeout
Response Timer for Multiplexer Control Channel (T2)
BTPROTO_SCO
SCO sockets provide sequential packet access to time sensitive data
channels over Bluetooth connections, typically used for audio data.
SCO socket options:
SO_SCO_MTU [uint16_t]
Maximum packet size for use on this link. This is read-only and
will be set by the protocol code when a connection is made.
Currently, due to limitations in the ubt(4) driver, the SCO
protocol code will only accept packets with exactly this size.
SO_SCO_HANDLE [uint16_t]
Connection handle for this link. This is read-only and provided
for informational purposes only.
SCO sysctl(8) controls:
net.bluetooth.sco.sendspace
Default send buffer size for SCO sockets.
net.bluetooth.sco.recvspace
Default receive buffer size for SCO sockets.
INFORMATION
The following ioctl(2) calls may be used to manipulate Bluetooth devices.
The ioctl(2) must be made on BTPROTO_HCI sockets. All of the requests
take a btreq structure defined as follows as their parameter and unless
otherwise specified, use the btr_name field to identify the device.
struct btreq {
char btr_name[HCI_DEVNAME_SIZE]; /* device name */
union {
struct {
bdaddr_t btri_bdaddr; /* device bdaddr */
uint16_t btri_flags; /* flags */
uint16_t btri_num_cmd; /* # of free cmd buffers */
uint16_t btri_num_acl; /* # of free ACL buffers */
uint16_t btri_num_sco; /* # of free SCO buffers */
uint16_t btri_acl_mtu; /* ACL mtu */
uint16_t btri_sco_mtu; /* SCO mtu */
uint16_t btri_link_policy; /* Link Policy */
uint16_t btri_packet_type; /* Packet Type */
uint16_t btri_max_acl; /* max ACL buffers */
uint16_t btri_max_sco; /* max SCO buffers */
} btri;
struct {
uint8_t btrf_page0[HCI_FEATURES_SIZE]; /* basic */
uint8_t btrf_page1[HCI_FEATURES_SIZE]; /* extended page 1 */
uint8_t btrf_page2[HCI_FEATURES_SIZE]; /* extended page 2 */
} btrf;
struct bt_stats btrs; /* unit stats */
} btru;
};
#define btr_flags btru.btri.btri_flags
#define btr_bdaddr btru.btri.btri_bdaddr
#define btr_num_cmd btru.btri.btri_num_cmd
#define btr_num_acl btru.btri.btri_num_acl
#define btr_num_sco btru.btri.btri_num_sco
#define btr_acl_mtu btru.btri.btri_acl_mtu
#define btr_sco_mtu btru.btri.btri_sco_mtu
#define btr_link_policy btru.btri.btri_link_policy
#define btr_packet_type btru.btri.btri_packet_type
#define btr_max_acl btru.btri.btri_max_acl
#define btr_max_sco btru.btri.btri_max_sco
#define btr_features0 btru.btrf.btrf_page0
#define btr_features1 btru.btrf.btrf_page1
#define btr_features2 btru.btrf.btrf_page2
#define btr_stats btru.btrs
/* btr_flags */
#define BTF_UP (1<<0) /* unit is up */
#define BTF_RUNNING (1<<1) /* unit is running */
#define BTF_XMIT_CMD (1<<2) /* transmitting CMD packets */
#define BTF_XMIT_ACL (1<<3) /* transmitting ACL packets */
#define BTF_XMIT_SCO (1<<4) /* transmitting SCO packets */
#define BTF_INIT_BDADDR (1<<5) /* waiting for bdaddr */
#define BTF_INIT_BUFFER_SIZE (1<<6) /* waiting for buffer size */
#define BTF_INIT_FEATURES (1<<7) /* waiting for features */
#define BTF_NOOP_ON_RESET (1<<8) /* wait for No-op on reset */
#define BTF_INIT_COMMANDS (1<<9) /* waiting for supported commands */
#define BTF_MASTER (1<<10) /* request Master role */
struct bt_stats {
uint32_t err_tx;
uint32_t err_rx;
uint32_t cmd_tx;
uint32_t evt_rx;
uint32_t acl_tx;
uint32_t acl_rx;
uint32_t sco_tx;
uint32_t sco_rx;
uint32_t byte_tx;
uint32_t byte_rx;
};
SIOCGBTINFO Get Bluetooth device Info. Given the device name, fill in
the btreq structure including the address field for use
with socket addressing as above.
SIOCGBTINFOA Get Bluetooth device Info from Address. Given the device
address, fill in the btreq structure including the name
field.
SIOCNBTINFO Next Bluetooth device Info. If name field is empty, the
first device will be returned. Otherwise, the next device
will be returned until no more devices are found when the
call will fail, with error ENXIO. Thus, you can cycle
through all devices in the system.
SIOCSBTFLAGS Set Bluetooth device Flags. Not all flags are settable.
SIOCGBTFEAT Get Bluetooth device Features. This returns the cached
basic (page 0) and extended (page 1 & 2) features.
SIOCSBTPOLICY Set Bluetooth device Link Policy. Link Policy bits are
defined in <netbt/hci.h>, though you can only set bits
that the device supports.
SIOCSBTPTYPE Set Bluetooth device Packet Types. You can only set
packet types that the device supports.
SIOCGBTSTATS Read device statistics.
SIOCZBTSTATS Read device statistics, and zero them.
Only the super-user may change device configurations.
SEE ALSO
bind(2), getsockname(2), bluetooth(3), bcsp(4), bt3c(4), btbc(4),
btuart(4), options(4), ubt(4)
HISTORY
The Bluetooth Protocol Stack was written for NetBSD 4.0 by Iain Hibbert
under the sponsorship of Itronix, Inc.
NetBSD 10.99 November 20, 2010 NetBSD 10.99