hci - Bluetooth HCI protocol

Free use of this software is granted under the terms of the GNU Lesser General Public Licenses (LGPL). BlueZ October 2024 HCI(7)

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.

hci - Bluetooth HCI protocol

<linux-bluetooth@vger.kernel.org>

<http://www.bluez.org>

socket(7)

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;

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(sinceLinux2.6) 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(sinceLinux5.16) 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(sinceLinux5.16) 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);

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