CAN Devices
[Device Profiles]

---

Detailed Description

This is the common interface a RTDM-compliant CAN device has to provide. Feel free to report bugs and comments on this profile to the "Socketcan" mailing list (Socketcan-core@lists.berlios.de) or directly to the authors (wg@grandegger.com or Sebastian.Smolorz@stud.uni-hannover.de).

Device Characteristics

Device Flags: RTDM_PROTOCOL_DEVICE

Protocol Family: PF_CAN

Socket Type: SOCK_RAW

Device Class: RTDM_CLASS_CAN

Supported Operations

Socket
Environments: non-RT (RT optional)

Specific return values:

• -EPROTONOSUPPORT (Protocol is not supported by the driver. See CAN protocols for possible protocols.)

Close
Blocking calls to any of the Send or Receive functions will be unblocked when the socket is closed and return with an error.

Environments: non-RT (RT optional)

Specific return values: none


IOCTL
Mandatory Environments: see below
Specific return values: see below


Bind
Binds a socket to one or all CAN devices (see struct sockaddr_can). If a filter list has been defined with setsockopt (see Sockopts), it will be used upon reception of CAN frames to decide whether the bound socket will receive a frame. If no filter has been defined, the socket will receive all CAN frames on the specified interface(s).

Binding to special interface index 0 will make the socket receive CAN frames from all CAN interfaces.

Binding to an interface index is also relevant for the Send functions because they will transmit a message over the interface the socket is bound to when no socket address is given to them.


Environments: non-RT (RT optional)

Specific return values:

• -EFAULT (It was not possible to access user space memory area at the specified address.)
• -ENOMEM (Not enough memory to fulfill the operation)
• -EINVAL (Invalid address family, or invalid length of address structure)
• -ENODEV (Invalid CAN interface index)
• -ENOSPC (No enough space for filter list)
• -EBADF (Socket is about to be closed)
• -EAGAIN (Too many receivers. Old binding (if any) is still active. Close some sockets and try again.)

Setsockopt, Getsockopt
These functions allow to set and get various socket options. Currently, only CAN raw sockets are supported.

Supported Levels and Options:

• Level SOL_CAN_RAW : CAN RAW protocol (see CAN_PROTO_RAW)
  • Option CAN_RAW_FILTER : CAN filter list
  • Option CAN_RAW_ERR_FILTER : CAN error mask
  • Option CAN_RAW_TX_LOOPBACK : CAN TX loopback to local sockets

Environments: non-RT (RT optional)
Specific return values: see links to options above.


Recv, Recvfrom, Recvmsg
These functions receive CAN messages from a socket. Only one message per call can be received, so only one buffer with the correct length must be passed. For SOCK_RAW, this is the size of struct can_frame.

Unlike a call to one of the Send functions, a Recv function will not return with an error if an interface is down (due to bus-off or setting of stop mode) or in sleep mode. Moreover, in such a case there may still be some CAN messages in the socket buffer which could be read out successfully.

It is possible to receive a high precision timestamp with every CAN message. The condition is a former instruction to the socket via RTCAN_RTIOC_TAKE_TIMESTAMP. The timestamp will be copied to the msg_control buffer of struct msghdr if it points to a valid memory location with size of nanosecs_abs_t. If this is a NULL pointer the timestamp will be discarded silently.

Note: A msg_controllen of 0 upon completion of the function call indicates that no timestamp is available for that message.

Supported Flags [in]:

• MSG_DONTWAIT (By setting this flag the operation will only succeed if it would not block, i.e. if there is a message in the socket buffer. This flag takes precedence over a timeout specified by RTCAN_RTIOC_RCV_TIMEOUT.)
• MSG_PEEK (Receive a message but leave it in the socket buffer. The next receive operation will get that message again.)

Supported Flags [out]: none

Environments: RT (non-RT optional)

Specific return values:

• Non-negative value (Indicating the successful reception of a CAN message. For SOCK_RAW, this is the size of struct can_frame regardless of the actual size of the payload.)
• -EFAULT (It was not possible to access user space memory area at one of the specified addresses.)
• -EINVAL (Unsupported flag detected, or invalid length of socket address buffer, or invalid length of message control buffer)
• -EMSGSIZE (Zero or more than one iovec buffer passed, or buffer too small)
• -EAGAIN (No data available in non-blocking mode)
• -EBADF (Socket was closed.)
• -EINTR (Operation was interrupted explicitly or by signal.)
• -ETIMEDOUT (Timeout)

Send, Sendto, Sendmsg
These functions send out CAN messages. Only one message per call can be transmitted, so only one buffer with the correct length must be passed. For SOCK_RAW, this is the size of struct can_frame.

The following only applies to SOCK_RAW: If a socket address of struct sockaddr_can is given, only can_ifindex is used. It is also possible to omit the socket address. Then the interface the socket is bound to will be used for sending messages.

If an interface goes down (due to bus-off or setting of stop mode) all senders that were blocked on this interface will be woken up.


Supported Flags:

• MSG_DONTWAIT (By setting this flag the transmit operation will only succeed if it would not block. This flag takes precedence over a timeout specified by RTCAN_RTIOC_SND_TIMEOUT.)

Environments: RT (non-RT optional)

Specific return values:

• Non-negative value equal to given buffer size (Indicating the successful completion of the function call. See also note.)
• -EOPNOTSUPP (MSG_OOB flag is not supported.)
• -EINVAL (Unsupported flag detected or: Invalid length of socket address or: Invalid address family or: Data length code of CAN frame not between 0 and 15 or: CAN standard frame has got an ID not between 0 and 2031)
• -EMSGSIZE (Zero or more than one buffer passed or invalid size of buffer)
• -EFAULT (It was not possible to access user space memory area at one of the specified addresses.)
• -ENXIO (Invalid CAN interface index - 0 is not allowed here - or socket not bound or rather bound to all interfaces.)
• -ENETDOWN (Controller is bus-off or in stopped state.)
• -ECOMM (Controller is sleeping)
• -EAGAIN (Cannot transmit without blocking but a non-blocking call was requested.)
• -EINTR (Operation was interrupted explicitly or by signal)
• -EBADF (Socket was closed.)
• -ETIMEDOUT (Timeout)

Note: A successful completion of the function call does not implicate a successful transmission of the message.

Files
file	rtcan.h
	Real-Time Driver Model for RT-Socket-CAN, CAN device profile header.
Data Structures
struct	can_bittime_std
	Standard bit-time parameters according to Bosch. More...
struct	can_bittime_btr
	Hardware-specific BTR bit-times. More...
struct	can_bittime
	Custom CAN bit-time definition. More...
struct	can_filter
	Filter for reception of CAN messages. More...
struct	sockaddr_can
	Socket address structure for the CAN address family. More...
struct	can_frame
	Raw CAN frame. More...
CAN ID masks
Bit masks for masking CAN IDs
#define	CAN_EFF_MASK   0x1FFFFFFF
	Bit mask for extended CAN IDs.
#define	CAN_SFF_MASK   0x000007FF
	Bit mask for standard CAN IDs.
CAN ID flags
Flags within a CAN ID indicating special CAN frame attributes
#define	CAN_EFF_FLAG   0x80000000
	extended frame
#define	CAN_RTR_FLAG   0x40000000
	remote transmission flag
#define	CAN_ERR_FLAG   0x20000000
	error frame (see Errors)
CAN controller modes
Special CAN controllers modes, which can be or'ed together.
#define	CAN_CTRLMODE_LISTENONLY   0x1
	Listen-Only mode.
#define	CAN_CTRLMODE_LOOPBACK   0x2
	Loopback mode.
Timestamp switches
Arguments to pass to RTCAN_RTIOC_TAKE_TIMESTAMP
#define	RTCAN_TAKE_NO_TIMESTAMPS   0
	Switch off taking timestamps.
#define	RTCAN_TAKE_TIMESTAMPS   1
	Do take timestamps.
RAW socket options
Setting and getting CAN RAW socket options.
#define	CAN_RAW_FILTER   0x1
	CAN filter definition.
#define	CAN_RAW_ERR_FILTER   0x2
	CAN error mask.
#define	CAN_RAW_TX_LOOPBACK   0x3
	CAN TX loopback.
IOCTLs
CAN device IOCTLs
#define	SIOCGIFINDEX   _IOWR(RTIOC_TYPE_CAN, 0x00, struct ifreq)
	Get CAN interface index by name.
#define	SIOCSCANBAUDRATE   _IOW(RTIOC_TYPE_CAN, 0x01, struct ifreq)
	Set baud rate.
#define	SIOCGCANBAUDRATE   _IOWR(RTIOC_TYPE_CAN, 0x02, struct ifreq)
	Get baud rate.
#define	SIOCSCANCUSTOMBITTIME   _IOW(RTIOC_TYPE_CAN, 0x03, struct ifreq)
	Set custom bit time parameter.
#define	SIOCGCANCUSTOMBITTIME   _IOWR(RTIOC_TYPE_CAN, 0x04, struct ifreq)
	Get custum bit-time parameters.
#define	SIOCSCANMODE   _IOW(RTIOC_TYPE_CAN, 0x05, struct ifreq)
	Set operation mode of CAN controller.
#define	SIOCGCANSTATE   _IOWR(RTIOC_TYPE_CAN, 0x06, struct ifreq)
	Get current state of CAN controller.
#define	SIOCSCANCTRLMODE   _IOW(RTIOC_TYPE_CAN, 0x07, struct ifreq)
	Set special controller modes.
#define	SIOCGCANCTRLMODE   _IOWR(RTIOC_TYPE_CAN, 0x08, struct ifreq)
	Get special controller modes.
#define	RTCAN_RTIOC_TAKE_TIMESTAMP   _IOW(RTIOC_TYPE_CAN, 0x09, int)
	Enable or disable storing a high precision timestamp upon reception of a CAN frame.
#define	RTCAN_RTIOC_RCV_TIMEOUT   _IOW(RTIOC_TYPE_CAN, 0x0A, nanosecs_rel_t)
	Specify a reception timeout for a socket.
#define	RTCAN_RTIOC_SND_TIMEOUT   _IOW(RTIOC_TYPE_CAN, 0x0B, nanosecs_rel_t)
	Specify a transmission timeout for a socket.
Error mask
Error class (mask) in can_id field of struct can_frame to be used with CAN_RAW_ERR_FILTER.
#define	CAN_ERR_TX_TIMEOUT   0x00000001U
	TX timeout (netdevice driver).
#define	CAN_ERR_LOSTARB   0x00000002U
	Lost arbitration (see data[0]).
#define	CAN_ERR_CRTL   0x00000004U
	Controller problems (see data[1]).
#define	CAN_ERR_PROT   0x00000008U
	Protocol violations (see data[2], data[3]).
#define	CAN_ERR_TRX   0x00000010U
	Transceiver status (see data[4]).
#define	CAN_ERR_ACK   0x00000020U
	Received no ACK on transmission.
#define	CAN_ERR_BUSOFF   0x00000040U
	Bus off.
#define	CAN_ERR_BUSERROR   0x00000080U
	Bus error (may flood!).
#define	CAN_ERR_RESTARTED   0x00000100U
	Controller restarted.
#define	CAN_ERR_MASK   0x1FFFFFFFU
	Omit EFF, RTR, ERR flags.
Arbitration lost error
Error in the data[0] field of struct can_frame.
#define	CAN_ERR_LOSTARB_UNSPEC   0x00
	unspecified else bit number in bitstream
Controller problems
Error in the data[1] field of struct can_frame.
#define	CAN_ERR_CRTL_UNSPEC   0x00
	unspecified
#define	CAN_ERR_CRTL_RX_OVERFLOW   0x01
	RX buffer overflow.
#define	CAN_ERR_CRTL_TX_OVERFLOW   0x02
	TX buffer overflow.
#define	CAN_ERR_CRTL_RX_WARNING   0x04
	reached warning level for RX errors
#define	CAN_ERR_CRTL_TX_WARNING   0x08
	reached warning level for TX errors
#define	CAN_ERR_CRTL_RX_PASSIVE   0x10
	reached passive level for RX errors
#define	CAN_ERR_CRTL_TX_PASSIVE   0x20
	reached passive level for TX errors
Protocol error type
Error in the data[2] field of struct can_frame.
#define	CAN_ERR_PROT_UNSPEC   0x00
	unspecified
#define	CAN_ERR_PROT_BIT   0x01
	single bit error
#define	CAN_ERR_PROT_FORM   0x02
	frame format error
#define	CAN_ERR_PROT_STUFF   0x04
	bit stuffing error
#define	CAN_ERR_PROT_BIT0   0x08
	unable to send dominant bit
#define	CAN_ERR_PROT_BIT1   0x10
	unable to send recessive bit
#define	CAN_ERR_PROT_OVERLOAD   0x20
	bus overload
#define	CAN_ERR_PROT_ACTIVE   0x40
	active error announcement
#define	CAN_ERR_PROT_TX   0x80
	error occured on transmission
Protocol error location
Error in the data[3] field of struct can_frame.
#define	CAN_ERR_PROT_LOC_UNSPEC   0x00
	unspecified
#define	CAN_ERR_PROT_LOC_SOF   0x03
	start of frame
#define	CAN_ERR_PROT_LOC_ID28_21   0x02
	ID bits 28 - 21 (SFF: 10 - 3).
#define	CAN_ERR_PROT_LOC_ID20_18   0x06
	ID bits 20 - 18 (SFF: 2 - 0 ).
#define	CAN_ERR_PROT_LOC_SRTR   0x04
	substitute RTR (SFF: RTR)
#define	CAN_ERR_PROT_LOC_IDE   0x05
	identifier extension
#define	CAN_ERR_PROT_LOC_ID17_13   0x07
	ID bits 17-13.
#define	CAN_ERR_PROT_LOC_ID12_05   0x0F
	ID bits 12-5.
#define	CAN_ERR_PROT_LOC_ID04_00   0x0E
	ID bits 4-0.
#define	CAN_ERR_PROT_LOC_RTR   0x0C
	RTR.
#define	CAN_ERR_PROT_LOC_RES1   0x0D
	reserved bit 1
#define	CAN_ERR_PROT_LOC_RES0   0x09
	reserved bit 0
#define	CAN_ERR_PROT_LOC_DLC   0x0B
	data length code
#define	CAN_ERR_PROT_LOC_DATA   0x0A
	data section
#define	CAN_ERR_PROT_LOC_CRC_SEQ   0x08
	CRC sequence.
#define	CAN_ERR_PROT_LOC_CRC_DEL   0x18
	CRC delimiter.
#define	CAN_ERR_PROT_LOC_ACK   0x19
	ACK slot.
#define	CAN_ERR_PROT_LOC_ACK_DEL   0x1B
	ACK delimiter.
#define	CAN_ERR_PROT_LOC_EOF   0x1A
	end of frame
#define	CAN_ERR_PROT_LOC_INTERM   0x12
	intermission
Protocol error location
Error in the data[4] field of struct can_frame.
#define	CAN_ERR_TRX_UNSPEC   0x00
	0000 0000
#define	CAN_ERR_TRX_CANH_NO_WIRE   0x04
	0000 0100
#define	CAN_ERR_TRX_CANH_SHORT_TO_BAT   0x05
	0000 0101
#define	CAN_ERR_TRX_CANH_SHORT_TO_VCC   0x06
	0000 0110
#define	CAN_ERR_TRX_CANH_SHORT_TO_GND   0x07
	0000 0111
#define	CAN_ERR_TRX_CANL_NO_WIRE   0x40
	0100 0000
#define	CAN_ERR_TRX_CANL_SHORT_TO_BAT   0x50
	0101 0000
#define	CAN_ERR_TRX_CANL_SHORT_TO_VCC   0x60
	0110 0000
#define	CAN_ERR_TRX_CANL_SHORT_TO_GND   0x70
	0111 0000
#define	CAN_ERR_TRX_CANL_SHORT_TO_CANH   0x80
	1000 0000
CAN protocols
Possible protocols for PF_CAN protocol family
enum	CAN_PROTO { CAN_PROTO_RAW }
CAN operation modes
Modes into which CAN controllers can be set
enum	CAN_MODE { CAN_MODE_STOP = 0, CAN_MODE_START, CAN_MODE_SLEEP }
CAN controller states
States a CAN controller can be in.
enum	CAN_STATE {   CAN_STATE_ACTIVE = 0, CAN_STATE_BUS_WARNING, CAN_STATE_BUS_PASSIVE, CAN_STATE_BUS_OFF,   CAN_STATE_SCANNING_BAUDRATE, CAN_STATE_STOPPED, CAN_STATE_SLEEPING }
Defines
#define	AF_CAN   29
	CAN address family.
#define	PF_CAN   AF_CAN
	CAN protocol family.
Typedefs
typedef uint32_t	can_id_t
	Type of CAN id (see CAN_xxx_MASK and CAN_xxx_FLAG).
typedef can_id_t	can_err_mask_t
	Type of CAN error mask.
typedef uint32_t	can_baudrate_t
	Baudrate definition in bits per second.
typedef enum CAN_BITTIME_TYPE	can_bittime_type_t
	See CAN_BITTIME_TYPE.
typedef enum CAN_MODE	can_mode_t
	See CAN_MODE.
typedef int	can_ctrlmode_t
	See CAN_CTRLMODE.
typedef enum CAN_STATE	can_state_t
	See CAN_STATE.
typedef can_filter	can_filter_t
	Filter for reception of CAN messages.
typedef can_frame	can_frame_t
	Raw CAN frame.
Enumerations
enum	CAN_BITTIME_TYPE { CAN_BITTIME_STD, CAN_BITTIME_BTR }
	Supported CAN bit-time types. More...

---

Define Documentation

#define CAN_RAW_ERR_FILTER   0x2

CAN error mask. A CAN error mask (see Errors) can be set with setsockopt. This mask is then used to decided if error frames are send to this socket in case of error condidtions. The error frames are marked with the CAN_ERR_FLAG of CAN_xxx_FLAG and must be handled by the application properly. A detailed description of the error can be found in the can_id and the data fields of struct can_frame (see Errors for futher details). Parameters: [in]  level  SOL_CAN_RAW [in]  optname  CAN_RAW_ERR_FILTER [in]  optval  Pointer to error mask of type can_err_mask_t. [in]  optlen  Size of error mask: sizeof(can_err_mask_t). Environments: non-RT (RT optional) Specific return values: -EFAULT (It was not possible to access user space memory area at the specified address.) -EINVAL (Invalid length "optlen")

#define CAN_RAW_FILTER   0x1

CAN filter definition. A CAN raw filter list with elements of struct can_filter can be installed with setsockopt. This list is used upon reception of CAN frames to decide whether the bound socket will receive a frame. An empty filter list can also be defined using optlen = 0, which is recommanded for write-only sockets. If the socket was already bound with Bind, the old filter list gets replaced with the new one. Be aware that already received, but not read out CAN frames may stay in the socket buffer. Parameters: [in]  level  SOL_CAN_RAW [in]  optname  CAN_RAW_FILTER [in]  optval  Pointer to array of struct can_filter. [in]  optlen  Size of filter list: count * sizeof( struct can_filter). Environments: non-RT (RT optional) Specific return values: -EFAULT (It was not possible to access user space memory area at the specified address.) -ENOMEM (Not enough memory to fulfill the operation) -EINVAL (Invalid length "optlen") -ENOSPC (No space to store filter list, check RT-Socket-CAN kernel parameters)

#define CAN_RAW_TX_LOOPBACK   0x3

CAN TX loopback. The TX loopback to other local sockets can be selected with this setsockopt. Note: The TX loopback feature must be enabled in the kernel and then the loopback to other local TX sockets is enabled by default. Parameters: [in]  level  SOL_CAN_RAW [in]  optname  CAN_RAW_TX_LOOPBACK [in]  optval  Pointer to integer value. [in]  optlen  Size of int: sizeof(int). Environments: non-RT (RT optional) Specific return values: -EFAULT (It was not possible to access user space memory area at the specified address.) -EINVAL (Invalid length "optlen") -EOPNOTSUPP (not supported, check RT-Socket-CAN kernel parameters).

#define RTCAN_RTIOC_RCV_TIMEOUT   _IOW(RTIOC_TYPE_CAN, 0x0A, nanosecs_rel_t)

Specify a reception timeout for a socket. Defines a timeout for all receive operations via a socket which will take effect when one of the receive functions is called without the MSG_DONTWAIT flag set. The default value for a newly created socket is an infinite timeout. Note: The setting of the timeout value is not done atomically to avoid locks. Please set the value before receiving messages from the socket. Parameters: [in]  arg  Pointer to nanosecs_rel_t variable. The value is interpreted as relative timeout in nanoseconds in case of a positive value. See Timeouts for special timeouts. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: never.

#define RTCAN_RTIOC_SND_TIMEOUT   _IOW(RTIOC_TYPE_CAN, 0x0B, nanosecs_rel_t)

Specify a transmission timeout for a socket. Defines a timeout for all send operations via a socket which will take effect when one of the send functions is called without the MSG_DONTWAIT flag set. The default value for a newly created socket is an infinite timeout. Note: The setting of the timeout value is not done atomically to avoid locks. Please set the value before sending messages to the socket. Parameters: [in]  arg  Pointer to nanosecs_rel_t variable. The value is interpreted as relative timeout in nanoseconds in case of a positive value. See Timeouts for special timeouts. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: never.

#define RTCAN_RTIOC_TAKE_TIMESTAMP   _IOW(RTIOC_TYPE_CAN, 0x09, int)

Enable or disable storing a high precision timestamp upon reception of a CAN frame. A newly created socket takes no timestamps by default. Parameters: [in]  arg  int variable, see Timestamp switches Returns: 0 on success. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Note: Activating taking timestamps only has an effect on newly received CAN messages from the bus. Frames that already are in the socket buffer do not have timestamps if it was deactivated before. See Receive for more details. Rescheduling: never.

#define SIOCGCANBAUDRATE   _IOWR(RTIOC_TYPE_CAN, 0x02, struct ifreq)

Get baud rate. Parameters: [in,out]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru will be filled with an instance of can_baudrate_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No baud rate was set yet. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: never.

#define SIOCGCANCTRLMODE   _IOWR(RTIOC_TYPE_CAN, 0x08, struct ifreq)

Get special controller modes. Parameters: [in]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru must be filled with an instance of can_ctrlmode_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No baud rate was set yet. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: possible.

#define SIOCGCANCUSTOMBITTIME   _IOWR(RTIOC_TYPE_CAN, 0x04, struct ifreq)

Get custum bit-time parameters. Parameters: [in,out]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru will be filled with an instance of struct can_bittime. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No baud rate was set yet. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: never.

#define SIOCGCANSTATE   _IOWR(RTIOC_TYPE_CAN, 0x06, struct ifreq)

Get current state of CAN controller. States are divided into main states and additional error indicators. A CAN controller is always in exactly one main state. CAN bus errors are registered by the CAN hardware and collected by the driver. There is one error indicator (bit) per error type. If this IOCTL is triggered the error types which occured since the last call of this IOCTL are reported and thereafter the error indicators are cleared. See also CAN controller states. Parameters: [in,out]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru will be filled with an instance of can_mode_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: possible.

#define SIOCGIFINDEX   _IOWR(RTIOC_TYPE_CAN, 0x00, struct ifreq)

Get CAN interface index by name. Parameters: [in,out]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). If ifr_name holds a valid CAN interface name ifr_ifindex will be filled with the corresponding interface index. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Rescheduling: never.

#define SIOCSCANBAUDRATE   _IOW(RTIOC_TYPE_CAN, 0x01, struct ifreq)

Set baud rate. The baudrate must be specified in bits per second. The driver will try to calculate resonable CAN bit-timing parameters. You can use SIOCSCANCUSTOMBITTIME to set custom bit-timing. Parameters: [in]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru must be filled with an instance of can_baudrate_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No valid baud rate, see can_baudrate_t. -EDOM : Baud rate not possible. -EAGAIN: Request could not be successully fulfilled. Try again. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Note: Setting the baud rate is a configuration task. It should be done deliberately or otherwise CAN messages will likely be lost. Rescheduling: possible.

#define SIOCSCANCTRLMODE   _IOW(RTIOC_TYPE_CAN, 0x07, struct ifreq)

Set special controller modes. Various special controller modes could be or'ed together (see CAN_CTRLMODE for further information). Parameters: [in]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru must be filled with an instance of can_ctrlmode_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No valid baud rate, see can_baudrate_t. -EAGAIN: Request could not be successully fulfilled. Try again. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Note: Setting specia controlelr modes is a configuration task. It should be done deliberately or otherwise CAN messages will likely be lost. Rescheduling: possible.

#define SIOCSCANCUSTOMBITTIME   _IOW(RTIOC_TYPE_CAN, 0x03, struct ifreq)

Set custom bit time parameter. Custem-bit time could be defined in various formats (see struct can_bittime). Parameters: [in]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru must be filled with an instance of struct can_bittime. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EINVAL: No valid baud rate, see can_baudrate_t. -EAGAIN: Request could not be successully fulfilled. Try again. Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Note: Setting the bit-time is a configuration task. It should be done deliberately or otherwise CAN messages will likely be lost. Rescheduling: possible.

#define SIOCSCANMODE   _IOW(RTIOC_TYPE_CAN, 0x05, struct ifreq)

Set operation mode of CAN controller. See CAN controller modes for available modes. Parameters: [in]  arg  Pointer to interface request structure buffer (struct ifreq from linux/if.h). ifr_name must hold a valid CAN interface name, ifr_ifru must be filled with an instance of can_mode_t. Returns: 0 on success, otherwise: -EFAULT: It was not possible to access user space memory area at the specified address. -ENODEV: No device with specified name exists. -EAGAIN: (CAN_MODE_START, CAN_MODE_STOP) Could not successfully set mode, hardware is busy. Try again. -EINVAL: (CAN_MODE_START) Cannot start controller, set baud rate first. -ENETDOWN: (CAN_MODE_SLEEP) Cannot go into sleep mode because controller is stopped or bus off. -EOPNOTSUPP: unknown mode Environments: This service can be called from: Kernel module initialization/cleanup code Kernel-based task User-space task (RT, non-RT) Note: Setting a CAN controller into normal operation after a bus-off can take some time (128 occurrences of 11 consecutive recessive bits). In such a case, although this IOCTL will return immediately with success and SIOCGCANSTATE will report CAN_STATE_ACTIVE, bus-off recovery may still be in progress. If a controller is bus-off, setting it into stop mode will return no error but the controller remains bus-off. Rescheduling: possible.

---

Typedef Documentation

typedef struct can_filter can_filter_t

Filter for reception of CAN messages. This filter works as follows: A received CAN ID is AND'ed bitwise with can_mask and then compared to can_id. If this comparison is true the message will be received by the socket. Multiple filters can be arranged in a filter list and set with Sockopts. If one of these filters matches a CAN ID upon reception of a CAN frame, this frame is accepted. Note: Only CAN_EFF_FLAG of CAN ID flags is valid for can_id and none for can_mask. This means that the RTR bit is not taken into account while filtering messages. Extended IDs are received only if CAN_EFF_FLAG is set in can_id. If it is cleared only standard IDs are accepted.

typedef struct can_frame can_frame_t

Raw CAN frame. Central structure for receiving and sending CAN frames.

---

Enumeration Type Documentation

enum CAN_BITTIME_TYPE

Supported CAN bit-time types. Enumerator: CAN_BITTIME_STD  Standard bit-time definition according to Bosch. CAN_BITTIME_BTR  Hardware-specific BTR bit-time definition.

enum CAN_MODE

Enumerator: CAN_MODE_STOP  Set controller in Stop mode (no reception / transmission possible). CAN_MODE_START  Set controller into normal operation. Coming from stopped mode or bus off, the controller begins with no errors in CAN_STATE_ACTIVE. CAN_MODE_SLEEP  Set controller into Sleep mode. This is only possible if the controller is not stopped or bus-off. Notice that sleep mode will only be entered when there is no bus activity. If the controller detects bus activity while "sleeping" it will go into operating mode again. To actively leave sleep mode again trigger CAN_MODE_START.

enum CAN_PROTO

Enumerator: CAN_PROTO_RAW  Raw protocol of PF_CAN, applicable to socket type SOCK_RAW.

enum CAN_STATE

Enumerator: CAN_STATE_ACTIVE  CAN controller is error active. CAN_STATE_BUS_WARNING  CAN controller is error active, warning level is reached. CAN_STATE_BUS_PASSIVE  CAN controller is error passive. CAN_STATE_BUS_OFF  CAN controller went into Bus Off. CAN_STATE_SCANNING_BAUDRATE  CAN controller is scanning to get the baudrate. CAN_STATE_STOPPED  CAN controller is in stopped mode. CAN_STATE_SLEEPING  CAN controller is in Sleep mode.

---