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can: canxl: add virtual CAN network identifier support

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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: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20240212213550.18516-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp 2024-02-12 22:35:50 +01:00 committed by Marc Kleine-Budde
parent 383de5664c
commit c83c22ec14
4 changed files with 110 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
include/uapi/linux/can.h
View file

@ -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 */

16
include/uapi/linux/can/raw.h
View file

@ -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 */

2
net/can/af_can.c
View file

@ -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));

93
net/can/raw.c
View file

@ -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);