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

BlueZ                            October 2024                           hci(7)