From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx> This adds initial documentation for RFCOMM sockets. --- Makefile.am | 4 +- doc/rfcomm.rst | 225 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 227 insertions(+), 2 deletions(-) create mode 100644 doc/rfcomm.rst diff --git a/Makefile.am b/Makefile.am index 8aedbb20d0d8..8f5d2fb553b4 100644 --- a/Makefile.am +++ b/Makefile.am @@ -348,7 +348,7 @@ CLEANFILES += $(builtin_files) if MANPAGES man_MANS += src/bluetoothd.8 -man_MANS += doc/l2cap.7 +man_MANS += doc/l2cap.7 doc/rfcomm.7 man_MANS += doc/org.bluez.Adapter.5 doc/org.bluez.Device.5 \ doc/org.bluez.DeviceSet.5 doc/org.bluez.AgentManager.5 \ doc/org.bluez.Agent.5 doc/org.bluez.ProfileManager.5 \ @@ -381,7 +381,7 @@ man_MANS += doc/org.bluez.obex.Client.5 doc/org.bluez.obex.Session.5 \ doc/org.bluez.obex.AgentManager.5 doc/org.bluez.obex.Agent.5 endif manual_pages += src/bluetoothd.8 -manual_pages += doc/l2cap.7 +manual_pages += doc/l2cap.7 doc/rfcomm.7 manual_pages += doc/org.bluez.Adapter.5 doc/org.bluez.Device.5 \ doc/org.bluez.DeviceSet.5 doc/org.bluez.AgentManager.5 \ doc/org.bluez.Agent.5 doc/org.bluez.ProfileManager.5 \ diff --git a/doc/rfcomm.rst b/doc/rfcomm.rst new file mode 100644 index 000000000000..4e43094b797d --- /dev/null +++ b/doc/rfcomm.rst @@ -0,0 +1,225 @@ +====== +rfcomm +====== + +--------------- +RFCOMM protocol +--------------- + +:Version: BlueZ +:Copyright: Free use of this software is granted under ther terms of the GNU + Lesser General Public Licenses (LGPL). +:Date: May 2024 +:Manual section: 7 +:Manual group: Linux System Administration + +SYNOPSIS +======== + +.. code-block:: c + + #include <sys/socket.h> + #include <bluetooth/bluetooth.h> + #include <bluetooth/rfcomm.h> + + rfcomm_socket = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM); + +DESCRIPTION +=========== + +The RFCOMM protocol provides emulation of serial ports over the L2CAP(7) +protocol. The protocol is based on the ETSI standard TS 07.10. + +RFCOMM is a simple transport protocol, with additional provisions for emulating +the 9 circuits of RS-232 (EIATIA-232-E) serial ports. + +SOCKET ADDRESS +============== + +.. code-block:: c + + struct sockaddr_rc { + sa_family_t rc_family; + unsigned short rc_bdaddr; + unsigned char rc_channel; + }; + +Example: + +.. code-block:: c + + struct sockaddr_rc addr; + + memset(&addr, 0, sizeof(addr)); + addr.rc_family = AF_BLUETOOTH; + bacpy(&addr.rc_bdaddr, bdaddr); + addr.rc_channel = channel; + +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. + +BT_SECURITY (since Linux 2.6.30) +-------------------------------- + +Channel security level, possible values: + +.. csv-table:: + :header: "Value", "Security Level", "Link Key Type", "Encryption" + :widths: auto + + **BT_SECURITY_SDP**, 0 (SDP Only), None, Not required + **BT_SECURITY_LOW**, 1 (Low), Unauthenticated, Not required + **BT_SECURITY_MEDIUM**, 2 (Medium - default), Unauthenticated, Desired + **BT_SECURITY_HIGH**, 3 (High), Authenticated, Required + **BT_SECURITY_FIPS** (since Linux 3.15), 4 (Secure Only), Authenticated (P-256 based Secure Simple Pairing and Secure Authentication), Required + +Example: + +.. code-block:: c + + int level = BT_SECURITY_HIGH; + int err = setsockopt(rfcomm_socket, SOL_BLUETOOTH, BT_SECURITY, &level, + sizeof(level)); + if (err == -1) { + perror("setsockopt"); + return 1; + } + +BT_DEFER_SETUP (since Linux 2.6.30) +----------------------------------- + +Channel defer connection setup, this control if the connection procedure +needs to be authorized by userspace before responding which allows +authorization at profile level, possible values: + +.. csv-table:: + :header: "Value", "Description", "Authorization" + :widths: auto + + **0**, Disable (default), Not required + **1**, Enable, Required + +Example: + +.. code-block:: c + + int defer_setup = 1; + int err = setsockopt(rfcomm_socket, SOL_BLUETOOTH, BT_DEFER_SETUP, + &defer_setup, sizeof(defer_setup)); + if (err == -1) { + perror("setsockopt"); + return err; + } + + err = listen(rfcomm_socket, 5); + if (err) { + perror("listen"); + return err; + } + + struct sockaddr_rc remote_addr = {0}; + socklen_t addr_len = sizeof(remote_addr); + int new_socket = accept(rfcomm_socket, (struct sockaddr*)&remote_addr, + &addr_len); + if (new_socket < 0) { + perror("accept"); + return new_socket; + } + + /* To complete the connection setup of new_socket read 1 byte */ + char c; + struct pollfd pfd; + + memset(&pfd, 0, sizeof(pfd)); + pfd.fd = new_socket; + pfd.events = POLLOUT; + + err = poll(&pfd, 1, 0); + if (err) { + perror("poll"); + return err; + } + + if (!(pfd.revents & POLLOUT)) { + err = read(sk, &c, 1); + if (err < 0) { + perror("read"); + return err; + } + } + +BT_FLUSHABLE (since Linux 2.6.39) +--------------------------------- + +Channel flushable flag, this control if the channel data can be flushed or +not, possible values: + +.. csv-table:: + :header: "Define", "Value", "Description" + :widths: auto + + **BT_FLUSHABLE_OFF**, 0x00 (default), Do not flush data + **BT_FLUSHABLE_ON**, 0x01, Flush data + +BT_POWER (since Linux 3.1) +-------------------------- + +Channel power policy, this control if the channel shall force exit of sniff +mode or not, possible values: + +.. csv-table:: + :header: "Define", "Value", "Description" + :widths: auto + + **BT_POWER_FORCE_ACTIVE_OFF**, 0x00 (default), Don't force exit of sniff mode + **BT_POWER_FORCE_ACTIVE_ON**, 0x01, Force exit of sniff mode + +BT_CHANNEL_POLICY (since Linux 3.10) +------------------------------------ + +High-speed (AMP) channel policy, possible values: + +.. csv-table:: + :header: "Define", "Value", "Description" + :widths: auto + + **BT_CHANNEL_POLICY_BREDR_ONLY**, 0 (default), BR/EDR only + **BT_CHANNEL_POLICY_BREDR_PREFERRED**, 1, BR/EDR Preferred + **BT_CHANNEL_POLICY_BREDR_PREFERRED**, 2, AMP Preferred + +BT_PHY (since Linux 5.10) +------------------------- + +Channel supported PHY(s), possible values: + +.. csv-table:: + :header: "Define", "Value", "Description" + :widths: auto + + **BT_PHY_BR_1M_1SLOT**, BIT 0, BR 1Mbps 1SLOT + **BT_PHY_BR_1M_3SLOT**, BIT 1, BR 1Mbps 3SLOT + **BT_PHY_BR_1M_5SLOT**, BIT 2, BR 1Mbps 5SLOT + **BT_PHY_BR_2M_1SLOT**, BIT 3, EDR 2Mbps 1SLOT + **BT_PHY_BR_2M_3SLOT**, BIT 4, EDR 2Mbps 3SLOT + **BT_PHY_BR_2M_5SLOT**, BIT 5, EDR 2Mbps 5SLOT + **BT_PHY_BR_3M_1SLOT**, BIT 6, EDR 3Mbps 1SLOT + **BT_PHY_BR_3M_3SLOT**, BIT 7, EDR 3Mbps 3SLOT + **BT_PHY_BR_3M_5SLOT**, BIT 8, EDR 3Mbps 5SLOT + +RESOURCES +========= + +http://www.bluez.org + +REPORTING BUGS +============== + +linux-bluetooth@xxxxxxxxxxxxxxx + +SEE ALSO +======== + +socket(7), rctest(1) -- 2.45.1