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HCI(7) Linux System Administration HCI(7)

NAME

hci - Bluetooth HCI protocol

SYNOPSIS

#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
hci_socket = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);


DESCRIPTION

Bluetooth Host Controller Interface (HCI) is the standard protocol to communicate with Bluetooth adapters. HCI protocol provides a uniform command method for the Host to access Controller capabilities and to control connections to other Controllers.

SOCKET ADDRESS

struct sockaddr_hci {


    sa_family_t    hci_family;


    unsigned short hci_dev;


    unsigned short hci_channel;
};


Possible values for hci_channel:

Define Value Description
HCI_CHANNEL_RAW 0x00 Raw channel - Used for raw HCI communication
HCI_CHANNEL_USER 0x01 User channel - Used for userspace HCI communication (disables kernel processing)
HCI_CHANNEL_MONITOR 0x02 Monitor channel - Used for monitoring HCI traffic (btmon(1))
HCI_CHANNEL_CONTROL 0x03 Control channel - Used to manage local adapters (bluetoothd(7))
HCI_CHANNEL_LOGGING 0x04 Logging channel - Used to inject logging messages (bluetoothd(7))

Example:

struct sockaddr_hci addr;
memset(&addr, 0, sizeof(addr));
addr.hci_family = AF_BLUETOOTH;
addr.hci_dev = HCI_DEV_NONE;
addr.hci_channel = HCI_CHANNEL_CONTROL;


SOCKET OPTIONS

The socket options listed below can be set by using setsockopt(2) and read with getsockopt(2) with the socket level set to SOL_BLUETOOTH or SOL_HCI (HCI_FILTER).

HCI_FILTER (since Linux 2.6)

Filter by HCI events, requires hci_channel to be set to HCI_CHANNEL_RAW, possible values:

struct hci_filter {


    uint32_t type_mask;


    uint32_t event_mask[2];


    uint16_t opcode;
};


Example:

struct hci_filter flt;
memset(&flt, 0, sizeof(flt));
flt.type_mask = 1 << BT_H4_EVT_PKT;
flt.event_mask[0] = 0xffffffff;
flt.event_mask[1] = 0xffffffff;
setsockopt(fd, SOL_HCI, HCI_FILTER, &flt, sizeof(flt));


BT_SNDBUF (since Linux 5.16)

Set send buffer size, requires hci_channel to be set to HCI_CHANNEL_MONITOR, HCI_CHANNEL_CONTROL or HCI_CHANNEL_LOGGING.

Default value is 1028.

Example:

uint16_t mtu = UINT16_MAX;
int err;
err = setsockopt(fd, SOL_BLUETOOTH, BT_SNDMTU, &mtu, sizeof(mtu));


BT_RCVBUF (since Linux 5.16)

Set receive buffer size, requires hci_channel to be set to HCI_CHANNEL_MONITOR, HCI_CHANNEL_CONTROL or HCI_CHANNEL_LOGGING.

Default value is 1028.

Example:

uint16_t mtu;
socklen_t len;
int err;
len = sizeof(mtu);
err = getsockopt(sock, SOL_BLUETOOTH, BT_RCVMTU, mtu, &len);


RESOURCES


<http://www.bluez.org>

REPORTING BUGS


<linux-bluetooth@vger.kernel.org>

SEE ALSO

socket(7)

COPYRIGHT

Free use of this software is granted under ther terms of the GNU Lesser General Public Licenses (LGPL).

October 2024 BlueZ