hci - Man Page
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
Reporting Bugs
<linux-bluetooth@vger.kernel.org>
See Also
Copyright
Free use of this software is granted under ther terms of the GNU Lesser General Public Licenses (LGPL).