hci - Bluetooth HCI protocol

NAME SYNOPSIS DESCRIPTION SOCKET ADDRESS SOCKET OPTIONS HCI_FILTER (since Linux 2.6) BT_SNDBUF (since Linux 5.16) BT_RCVBUF (since Linux 5.16) RESOURCES REPORTING BUGS SEE ALSO COPYRIGHT

SYNOPSIS

#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>

hci_socket = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);

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:

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);