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 the terms of the GNU Lesser General Public Licenses (LGPL).