Commit c83c22ec authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: canxl: add virtual CAN network identifier support 



CAN XL data frames contain an 8-bit virtual CAN network identifier (VCID).
A VCID value of zero represents an 'untagged' CAN XL frame.

To receive and send these optional VCIDs via CAN_RAW sockets a new socket
option CAN_RAW_XL_VCID_OPTS is introduced to define/access VCID content:

- tx: set the outgoing VCID value by the kernel (one fixed 8-bit value)
- tx: pass through VCID values from the user space (e.g. for traffic replay)
- rx: apply VCID receive filter (value/mask) to be passed to the user space

With the 'tx pass through' option CAN_RAW_XL_VCID_TX_PASS all valid VCID
values can be sent, e.g. to replay full qualified CAN XL traffic.

The VCID value provided for the CAN_RAW_XL_VCID_TX_SET option will
override the VCID value in the struct canxl_frame.prio defined for
CAN_RAW_XL_VCID_TX_PASS when both flags are set.

With a rx_vcid_mask of zero all possible VCID values (0x00 - 0xFF) are
passed to the user space when the CAN_RAW_XL_VCID_RX_FILTER flag is set.
Without this flag only untagged CAN XL frames (VCID = 0x00) are delivered
to the user space (default).

The 8-bit VCID is stored inside the CAN XL prio element (only in CAN XL
frames!) to not interfere with other CAN content or the CAN filters
provided by the CAN_RAW sockets and kernel infrastruture.

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20240212213550.18516-1-socketcan@hartkopp.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 383de566

include/uapi/linux/can.h

+7 −2
Original line number Diff line number Diff line
@@ -193,9 +193,14 @@ struct canfd_frame { 
#define CANXL_XLF 0x80 /* mandatory CAN XL frame flag (must always be set!) */

#define CANXL_SEC 0x01 /* Simple Extended Content (security/segmentation) */



/* the 8-bit VCID is optionally placed in the canxl_frame.prio element */

#define CANXL_VCID_OFFSET 16 /* bit offset of VCID in prio element */

#define CANXL_VCID_VAL_MASK 0xFFUL /* VCID is an 8-bit value */

#define CANXL_VCID_MASK (CANXL_VCID_VAL_MASK << CANXL_VCID_OFFSET)



/**

 * struct canxl_frame - CAN with e'X'tended frame 'L'ength frame structure

 * @prio:  11 bit arbitration priority with zero'ed CAN_*_FLAG flags

 * @prio:  11 bit arbitration priority with zero'ed CAN_*_FLAG flags / VCID

 * @flags: additional flags for CAN XL

 * @sdt:   SDU (service data unit) type

 * @len:   frame payload length in byte (CANXL_MIN_DLEN .. CANXL_MAX_DLEN)
@@ -205,7 +210,7 @@ struct canfd_frame { 
 * @prio shares the same position as @can_id from struct can[fd]_frame.

 */

struct canxl_frame {

	canid_t prio;  /* 11 bit priority for arbitration (canid_t) */

	canid_t prio;  /* 11 bit priority for arbitration / 8 bit VCID */

	__u8    flags; /* additional flags for CAN XL */

	__u8    sdt;   /* SDU (service data unit) type */

	__u16   len;   /* frame payload length in byte */

include/uapi/linux/can/raw.h

+16 −0
Original line number Diff line number Diff line
@@ -65,6 +65,22 @@ enum { 
	CAN_RAW_FD_FRAMES,	/* allow CAN FD frames (default:off) */

	CAN_RAW_JOIN_FILTERS,	/* all filters must match to trigger */

	CAN_RAW_XL_FRAMES,	/* allow CAN XL frames (default:off) */

	CAN_RAW_XL_VCID_OPTS,	/* CAN XL VCID configuration options */

};



/* configuration for CAN XL virtual CAN identifier (VCID) handling */

struct can_raw_vcid_options {



	__u8 flags;		/* flags for vcid (filter) behaviour */

	__u8 tx_vcid;		/* VCID value set into canxl_frame.prio */

	__u8 rx_vcid;		/* VCID value for VCID filter */

	__u8 rx_vcid_mask;	/* VCID mask for VCID filter */



};



/* can_raw_vcid_options.flags for CAN XL virtual CAN identifier handling */

#define CAN_RAW_XL_VCID_TX_SET		0x01

#define CAN_RAW_XL_VCID_TX_PASS		0x02

#define CAN_RAW_XL_VCID_RX_FILTER	0x04



#endif /* !_UAPI_CAN_RAW_H */

net/can/af_can.c

+2 −0
Original line number Diff line number Diff line
@@ -865,6 +865,8 @@ static __init int can_init(void) 
	/* check for correct padding to be able to use the structs similarly */

	BUILD_BUG_ON(offsetof(struct can_frame, len) !=

		     offsetof(struct canfd_frame, len) ||

		     offsetof(struct can_frame, len) !=

		     offsetof(struct canxl_frame, flags) ||

		     offsetof(struct can_frame, data) !=

		     offsetof(struct canfd_frame, data));

net/can/raw.c

+85 −8
Original line number Diff line number Diff line
@@ -91,6 +91,10 @@ struct raw_sock { 
	int recv_own_msgs;

	int fd_frames;

	int xl_frames;

	struct can_raw_vcid_options raw_vcid_opts;

	canid_t tx_vcid_shifted;

	canid_t rx_vcid_shifted;

	canid_t rx_vcid_mask_shifted;

	int join_filters;

	int count;                 /* number of active filters */

	struct can_filter dfilter; /* default/single filter */
@@ -134,10 +138,29 @@ static void raw_rcv(struct sk_buff *oskb, void *data) 
		return;



	/* make sure to not pass oversized frames to the socket */

	if ((!ro->fd_frames && can_is_canfd_skb(oskb)) ||

	    (!ro->xl_frames && can_is_canxl_skb(oskb)))

	if (!ro->fd_frames && can_is_canfd_skb(oskb))

		return;



	if (can_is_canxl_skb(oskb)) {

		struct canxl_frame *cxl = (struct canxl_frame *)oskb->data;



		/* make sure to not pass oversized frames to the socket */

		if (!ro->xl_frames)

			return;



		/* filter CAN XL VCID content */

		if (ro->raw_vcid_opts.flags & CAN_RAW_XL_VCID_RX_FILTER) {

			/* apply VCID filter if user enabled the filter */

			if ((cxl->prio & ro->rx_vcid_mask_shifted) !=

			    (ro->rx_vcid_shifted & ro->rx_vcid_mask_shifted))

				return;

		} else {

			/* no filter => do not forward VCID tagged frames */

			if (cxl->prio & CANXL_VCID_MASK)

				return;

		}

	}



	/* eliminate multiple filter matches for the same skb */

	if (this_cpu_ptr(ro->uniq)->skb == oskb &&

	    this_cpu_ptr(ro->uniq)->skbcnt == can_skb_prv(oskb)->skbcnt) {
@@ -698,6 +721,19 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, 
			ro->fd_frames = ro->xl_frames;

		break;



	case CAN_RAW_XL_VCID_OPTS:

		if (optlen != sizeof(ro->raw_vcid_opts))

			return -EINVAL;



		if (copy_from_sockptr(&ro->raw_vcid_opts, optval, optlen))

			return -EFAULT;



		/* prepare 32 bit values for handling in hot path */

		ro->tx_vcid_shifted = ro->raw_vcid_opts.tx_vcid << CANXL_VCID_OFFSET;

		ro->rx_vcid_shifted = ro->raw_vcid_opts.rx_vcid << CANXL_VCID_OFFSET;

		ro->rx_vcid_mask_shifted = ro->raw_vcid_opts.rx_vcid_mask << CANXL_VCID_OFFSET;

		break;



	case CAN_RAW_JOIN_FILTERS:

		if (optlen != sizeof(ro->join_filters))

			return -EINVAL;
@@ -786,6 +822,21 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, 
		val = &ro->xl_frames;

		break;



	case CAN_RAW_XL_VCID_OPTS:

		/* user space buffer to small for VCID opts? */

		if (len < sizeof(ro->raw_vcid_opts)) {

			/* return -ERANGE and needed space in optlen */

			err = -ERANGE;

			if (put_user(sizeof(ro->raw_vcid_opts), optlen))

				err = -EFAULT;

		} else {

			if (len > sizeof(ro->raw_vcid_opts))

				len = sizeof(ro->raw_vcid_opts);

			if (copy_to_user(optval, &ro->raw_vcid_opts, len))

				err = -EFAULT;

		}

		break;



	case CAN_RAW_JOIN_FILTERS:

		if (len > sizeof(int))

			len = sizeof(int);
@@ -803,23 +854,41 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, 
	return 0;

}



static bool raw_bad_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu)

static void raw_put_canxl_vcid(struct raw_sock *ro, struct sk_buff *skb)

{

	struct canxl_frame *cxl = (struct canxl_frame *)skb->data;



	/* sanitize non CAN XL bits */

	cxl->prio &= (CANXL_PRIO_MASK | CANXL_VCID_MASK);



	/* clear VCID in CAN XL frame if pass through is disabled */

	if (!(ro->raw_vcid_opts.flags & CAN_RAW_XL_VCID_TX_PASS))

		cxl->prio &= CANXL_PRIO_MASK;



	/* set VCID in CAN XL frame if enabled */

	if (ro->raw_vcid_opts.flags & CAN_RAW_XL_VCID_TX_SET) {

		cxl->prio &= CANXL_PRIO_MASK;

		cxl->prio |= ro->tx_vcid_shifted;

	}

}



static unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu)

{

	/* Classical CAN -> no checks for flags and device capabilities */

	if (can_is_can_skb(skb))

		return false;

		return CAN_MTU;



	/* CAN FD -> needs to be enabled and a CAN FD or CAN XL device */

	if (ro->fd_frames && can_is_canfd_skb(skb) &&

	    (mtu == CANFD_MTU || can_is_canxl_dev_mtu(mtu)))

		return false;

		return CANFD_MTU;



	/* CAN XL -> needs to be enabled and a CAN XL device */

	if (ro->xl_frames && can_is_canxl_skb(skb) &&

	    can_is_canxl_dev_mtu(mtu))

		return false;

		return CANXL_MTU;



	return true;

	return 0;

}



static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
@@ -829,6 +898,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	struct sockcm_cookie sockc;

	struct sk_buff *skb;

	struct net_device *dev;

	unsigned int txmtu;

	int ifindex;

	int err = -EINVAL;
@@ -869,9 +939,16 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
		goto free_skb;



	err = -EINVAL;

	if (raw_bad_txframe(ro, skb, dev->mtu))



	/* check for valid CAN (CC/FD/XL) frame content */

	txmtu = raw_check_txframe(ro, skb, dev->mtu);

	if (!txmtu)

		goto free_skb;



	/* only CANXL: clear/forward/set VCID value */

	if (txmtu == CANXL_MTU)

		raw_put_canxl_vcid(ro, skb);



	sockcm_init(&sockc, sk);

	if (msg->msg_controllen) {

		err = sock_cmsg_send(sk, msg, &sockc);