Merge patch series "can: support CAN XL"

Oliver Hartkopp <socketcan@hartkopp.net> says:

The CAN with eXtended data Length (CAN XL) is a new CAN protocol with
a 10Mbit/s data transfer with a new physical layer transceiver (for
this data section). CAN XL allows up to 2048 byte of payload and
shares the arbitration principle (11 bit priority) known from
Classical CAN and CAN FD. RTR and 29 bit identifiers are not
implemented in CAN XL.

A short introduction to CAN XL can be found here:
https://www.can-cia.org/can-knowledge/can/can-xl/
https://github.com/linux-can/can-doc/blob/master/presentations/CAN-XL-Intro.pdf

V1: https://lore.kernel.org/all/20220711183426.96446-1-socketcan@hartkopp.net

V2: Major rework after discussion and feedback on Linux-CAN ML
    https://lore.kernel.org/all/20220714160541.2071-1-socketcan@hartkopp.net

- rework of struct canxl_frame
- CANXL_XLF flag is now the switch between CAN XL and CAN/CANFD
- variable length in r/w operations for CAN XL frames
- write CAN XL frame to raw socket enforces size <-> canxl_frame.len sync

V3: Fix length for CAN XL frames inside the sk_buff
    https://lore.kernel.org/all/20220717132730.30295-1-socketcan@hartkopp.net

- extend the CAN_RAW sockopt to handle fixed/truncated read/write operations

V4: Fix patch 5 (can: raw: add CAN XL support)
    https://lore.kernel.org/all/20220719054204.29061-1-socketcan@hartkopp.net

- fix return value (move 'err = -EINVAL' in raw_sendmsg())
- add CAN XL frame handling in can_rcv()
- change comment for CAN_RAW_XL_[RT]X_DYN definition (allow -> enable)

V5: Remove CAN_RAW_XL_[RT]X_DYN definition again
    https://lore.kernel.org/all/20220719112748.3281-1-socketcan@hartkopp.net

- CAN_RAW_XL_[RT]X_DYN (truncated data) feature is now enabled by default
- use CANXL_MIN_DLEN instead of '1' in canxl_frame definition
- add missing 'err = -EINVAL' initialization in raw_sendmsg())

V6: https://lore.kernel.org/all/20220724074402.117394-1-socketcan@hartkopp.net

- rework an separate skb identification and length helpers
- add CANFD_FDF flag in all CAN FD frame structures
- simplify patches for infrastructure and raw sockets
- add vxcan support in virtual CAN interface patch

V7: https://lore.kernel.org/all/20220729154107.1875-1-socketcan@hartkopp.net

- fixed indention as remarked by Marc
- set CANFD_FDF flag when detecting CAN FD frames generated by PF_PACKET
- Allow to use variable CAN XL MTU sizes to enforce real time requirements
  on CAN XL segments (e.g. to support of CAN CiA segmentation concept)

V8: https://lore.kernel.org/all/20220801190010.3344-1-socketcan@hartkopp.net

- fixed typo as remarked by Vincent
- rebased to latest can-next/net-next tree

V9: https://lore.kernel.org/all/20220912170725.120748-1-socketcan@hartkopp.net

- rebased to latest can-next/net-next tree
- updated and extended public available CAN XL documenatation in cover letter
- renamed struct canxl_frame variable cfx to cxl as suggested by Vincent
- Added Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> tag

Link: https://lore.kernel.org/all/20220912170725.120748-1-socketcan@hartkopp.netSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/ctucanfd/ctucanfd_base.c

@@ -657,7 +657,6 @@ static void ctucan_read_rx_frame(struct ctucan_priv *priv, struct canfd_frame *c
 		cf->can_id = (idw >> 18) & CAN_SFF_MASK;
 
 	/* BRS, ESI, RTR Flags */
-	cf->flags = 0;
 	if (FIELD_GET(REG_FRAME_FORMAT_W_FDF, ffw)) {
 		if (FIELD_GET(REG_FRAME_FORMAT_W_BRS, ffw))
 			cf->flags |= CANFD_BRS;

drivers/net/can/dev/rx-offload.c

@@ -247,7 +247,7 @@ unsigned int can_rx_offload_get_echo_skb(struct can_rx_offload *offload,
 	struct net_device *dev = offload->dev;
 	struct net_device_stats *stats = &dev->stats;
 	struct sk_buff *skb;
-	u8 len;
+	unsigned int len;
 	int err;
 
 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);

drivers/net/can/dev/skb.c

@@ -91,8 +91,8 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 EXPORT_SYMBOL_GPL(can_put_echo_skb);
 
 struct sk_buff *
-__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr,
-		   unsigned int *frame_len_ptr)
+__can_get_echo_skb(struct net_device *dev, unsigned int idx,
+		   unsigned int *len_ptr, unsigned int *frame_len_ptr)
 {
 	struct can_priv *priv = netdev_priv(dev);
 
@@ -108,16 +108,12 @@ __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr,
 		 */
 		struct sk_buff *skb = priv->echo_skb[idx];
 		struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
-		struct canfd_frame *cf = (struct canfd_frame *)skb->data;
 
 		if (skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)
 			skb_tstamp_tx(skb, skb_hwtstamps(skb));
 
 		/* get the real payload length for netdev statistics */
-		if (cf->can_id & CAN_RTR_FLAG)
-			*len_ptr = 0;
-		else
-			*len_ptr = cf->len;
+		*len_ptr = can_skb_get_data_len(skb);
 
 		if (frame_len_ptr)
 			*frame_len_ptr = can_skb_priv->frame_len;
@@ -147,7 +143,7 @@ unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx,
 			      unsigned int *frame_len_ptr)
 {
 	struct sk_buff *skb;
-	u8 len;
+	unsigned int len;
 
 	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
 	if (!skb)
@@ -191,6 +187,20 @@ void can_free_echo_skb(struct net_device *dev, unsigned int idx,
 }
 EXPORT_SYMBOL_GPL(can_free_echo_skb);
 
+/* fill common values for CAN sk_buffs */
+static void init_can_skb_reserve(struct sk_buff *skb)
+{
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->skbcnt = 0;
+}
+
 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 {
 	struct sk_buff *skb;
@@ -204,16 +214,8 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 	}
 
 	skb->protocol = htons(ETH_P_CAN);
-	skb->pkt_type = PACKET_BROADCAST;
-	skb->ip_summed = CHECKSUM_UNNECESSARY;
-
-	skb_reset_mac_header(skb);
-	skb_reset_network_header(skb);
-	skb_reset_transport_header(skb);
-
-	can_skb_reserve(skb);
+	init_can_skb_reserve(skb);
 	can_skb_prv(skb)->ifindex = dev->ifindex;
-	can_skb_prv(skb)->skbcnt = 0;
 
 	*cf = skb_put_zero(skb, sizeof(struct can_frame));
 
@@ -235,23 +237,51 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 	}
 
 	skb->protocol = htons(ETH_P_CANFD);
-	skb->pkt_type = PACKET_BROADCAST;
-	skb->ip_summed = CHECKSUM_UNNECESSARY;
-
-	skb_reset_mac_header(skb);
-	skb_reset_network_header(skb);
-	skb_reset_transport_header(skb);
-
-	can_skb_reserve(skb);
+	init_can_skb_reserve(skb);
 	can_skb_prv(skb)->ifindex = dev->ifindex;
-	can_skb_prv(skb)->skbcnt = 0;
 
 	*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
 
+	/* set CAN FD flag by default */
+	(*cfd)->flags = CANFD_FDF;
+
 	return skb;
 }
 EXPORT_SYMBOL_GPL(alloc_canfd_skb);
 
+struct sk_buff *alloc_canxl_skb(struct net_device *dev,
+				struct canxl_frame **cxl,
+				unsigned int data_len)
+{
+	struct sk_buff *skb;
+
+	if (data_len < CANXL_MIN_DLEN || data_len > CANXL_MAX_DLEN)
+		goto out_error;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       CANXL_HDR_SIZE + data_len);
+	if (unlikely(!skb))
+		goto out_error;
+
+	skb->protocol = htons(ETH_P_CANXL);
+	init_can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*cxl = skb_put_zero(skb, CANXL_HDR_SIZE + data_len);
+
+	/* set CAN XL flag and length information by default */
+	(*cxl)->flags = CANXL_XLF;
+	(*cxl)->len = data_len;
+
+	return skb;
+
+out_error:
+	*cxl = NULL;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(alloc_canxl_skb);
+
 struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
 {
 	struct sk_buff *skb;
@@ -291,6 +321,14 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
 		skb_reset_mac_header(skb);
 		skb_reset_network_header(skb);
 		skb_reset_transport_header(skb);
+
+		/* set CANFD_FDF flag for CAN FD frames */
+		if (can_is_canfd_skb(skb)) {
+			struct canfd_frame *cfd;
+
+			cfd = (struct canfd_frame *)skb->data;
+			cfd->flags |= CANFD_FDF;
+		}
 	}
 
 	return true;
@@ -299,18 +337,25 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
 /* Drop a given socketbuffer if it does not contain a valid CAN frame. */
 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
 {
-	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct can_priv *priv = netdev_priv(dev);
 
-	if (skb->protocol == htons(ETH_P_CAN)) {
-		if (unlikely(skb->len != CAN_MTU ||
-			     cfd->len > CAN_MAX_DLEN))
+	switch (ntohs(skb->protocol)) {
+	case ETH_P_CAN:
+		if (!can_is_can_skb(skb))
 			goto inval_skb;
-	} else if (skb->protocol == htons(ETH_P_CANFD)) {
-		if (unlikely(skb->len != CANFD_MTU ||
-			     cfd->len > CANFD_MAX_DLEN))
+		break;
+
+	case ETH_P_CANFD:
+		if (!can_is_canfd_skb(skb))
 			goto inval_skb;
-	} else {
+		break;
+
+	case ETH_P_CANXL:
+		if (!can_is_canxl_skb(skb))
+			goto inval_skb;
+		break;
+
+	default:
 		goto inval_skb;
 	}
 

drivers/net/can/vcan.c

@@ -71,11 +71,10 @@ MODULE_PARM_DESC(echo, "Echo sent frames (for testing). Default: 0 (Off)");
 
 static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 {
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
 
 	stats->rx_packets++;
-	stats->rx_bytes += cfd->len;
+	stats->rx_bytes += can_skb_get_data_len(skb);
 
 	skb->pkt_type  = PACKET_BROADCAST;
 	skb->dev       = dev;
@@ -86,14 +85,14 @@ static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 
 static netdev_tx_t vcan_tx(struct sk_buff *skb, struct net_device *dev)
 {
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct net_device_stats *stats = &dev->stats;
-	int loop, len;
+	unsigned int len;
+	int loop;
 
 	if (can_dropped_invalid_skb(dev, skb))
 		return NETDEV_TX_OK;
 
-	len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len;
+	len = can_skb_get_data_len(skb);
 	stats->tx_packets++;
 	stats->tx_bytes += len;
 
@@ -137,7 +136,8 @@ static int vcan_change_mtu(struct net_device *dev, int new_mtu)
 	if (dev->flags & IFF_UP)
 		return -EBUSY;
 
-	if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
+	if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU &&
+	    !can_is_canxl_dev_mtu(new_mtu))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;

drivers/net/can/vxcan.c

@@ -38,10 +38,9 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *oskb, struct net_device *dev)
 {
 	struct vxcan_priv *priv = netdev_priv(dev);
 	struct net_device *peer;
-	struct canfd_frame *cfd = (struct canfd_frame *)oskb->data;
 	struct net_device_stats *peerstats, *srcstats = &dev->stats;
 	struct sk_buff *skb;
-	u8 len;
+	unsigned int len;
 
 	if (can_dropped_invalid_skb(dev, oskb))
 		return NETDEV_TX_OK;
@@ -70,7 +69,7 @@ static netdev_tx_t vxcan_xmit(struct sk_buff *oskb, struct net_device *dev)
 	skb->dev        = peer;
 	skb->ip_summed  = CHECKSUM_UNNECESSARY;
 
-	len = cfd->can_id & CAN_RTR_FLAG ? 0 : cfd->len;
+	len = can_skb_get_data_len(skb);
 	if (netif_rx(skb) == NET_RX_SUCCESS) {
 		srcstats->tx_packets++;
 		srcstats->tx_bytes += len;
@@ -132,7 +131,8 @@ static int vxcan_change_mtu(struct net_device *dev, int new_mtu)
 	if (dev->flags & IFF_UP)
 		return -EBUSY;
 
-	if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU)
+	if (new_mtu != CAN_MTU && new_mtu != CANFD_MTU &&
+	    !can_is_canxl_dev_mtu(new_mtu))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;

include/linux/can/dev.h

@@ -147,6 +147,11 @@ static inline u32 can_get_static_ctrlmode(struct can_priv *priv)
 	return priv->ctrlmode & ~priv->ctrlmode_supported;
 }
 
+static inline bool can_is_canxl_dev_mtu(unsigned int mtu)
+{
+	return (mtu >= CANXL_MIN_MTU && mtu <= CANXL_MAX_MTU);
+}
+
 void can_setup(struct net_device *dev);
 
 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,

include/linux/can/skb.h

@@ -20,7 +20,8 @@ void can_flush_echo_skb(struct net_device *dev);
 int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 		     unsigned int idx, unsigned int frame_len);
 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
-				   u8 *len_ptr, unsigned int *frame_len_ptr);
+				   unsigned int *len_ptr,
+				   unsigned int *frame_len_ptr);
 unsigned int __must_check can_get_echo_skb(struct net_device *dev,
 					   unsigned int idx,
 					   unsigned int *frame_len_ptr);
@@ -29,6 +30,9 @@ void can_free_echo_skb(struct net_device *dev, unsigned int idx,
 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 				struct canfd_frame **cfd);
+struct sk_buff *alloc_canxl_skb(struct net_device *dev,
+				struct canxl_frame **cxl,
+				unsigned int data_len);
 struct sk_buff *alloc_can_err_skb(struct net_device *dev,
 				  struct can_frame **cf);
 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb);
@@ -97,10 +101,59 @@ static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
 	return nskb;
 }
 
+static inline bool can_is_can_skb(const struct sk_buff *skb)
+{
+	struct can_frame *cf = (struct can_frame *)skb->data;
+
+	/* the CAN specific type of skb is identified by its data length */
+	return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);
+}
+
 static inline bool can_is_canfd_skb(const struct sk_buff *skb)
 {
+	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
 	/* the CAN specific type of skb is identified by its data length */
-	return skb->len == CANFD_MTU;
+	return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);
+}
+
+static inline bool can_is_canxl_skb(const struct sk_buff *skb)
+{
+	const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
+
+	if (skb->len < CANXL_HDR_SIZE + CANXL_MIN_DLEN || skb->len > CANXL_MTU)
+		return false;
+
+	/* this also checks valid CAN XL data length boundaries */
+	if (skb->len != CANXL_HDR_SIZE + cxl->len)
+		return false;
+
+	return cxl->flags & CANXL_XLF;
+}
+
+/* get length element value from can[|fd|xl]_frame structure */
+static inline unsigned int can_skb_get_len_val(struct sk_buff *skb)
+{
+	const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
+	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
+	if (can_is_canxl_skb(skb))
+		return cxl->len;
+
+	return cfd->len;
+}
+
+/* get needed data length inside CAN frame for all frame types (RTR aware) */
+static inline unsigned int can_skb_get_data_len(struct sk_buff *skb)
+{
+	unsigned int len = can_skb_get_len_val(skb);
+	const struct can_frame *cf = (struct can_frame *)skb->data;
+
+	/* RTR frames have an actual length of zero */
+	if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG)
+		return 0;
+
+	return len;
 }
 
 #endif /* !_CAN_SKB_H */

include/uapi/linux/can.h

@@ -48,6 +48,7 @@
 
 #include <linux/types.h>
 #include <linux/socket.h>
+#include <linux/stddef.h> /* for offsetof */
 
 /* controller area network (CAN) kernel definitions */
 
@@ -60,6 +61,7 @@
 #define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
 #define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
 #define CAN_ERR_MASK 0x1FFFFFFFU /* omit EFF, RTR, ERR flags */
+#define CANXL_PRIO_MASK CAN_SFF_MASK /* 11 bit priority mask */
 
 /*
  * Controller Area Network Identifier structure
@@ -73,6 +75,7 @@ typedef __u32 canid_t;
 
 #define CAN_SFF_ID_BITS		11
 #define CAN_EFF_ID_BITS		29
+#define CANXL_PRIO_BITS		CAN_SFF_ID_BITS
 
 /*
  * Controller Area Network Error Message Frame Mask structure
@@ -91,6 +94,16 @@ typedef __u32 can_err_mask_t;
 #define CANFD_MAX_DLC 15
 #define CANFD_MAX_DLEN 64
 
+/*
+ * CAN XL payload length and DLC definitions according to ISO 11898-1
+ * CAN XL DLC ranges from 0 .. 2047 => data length from 1 .. 2048 byte
+ */
+#define CANXL_MIN_DLC 0
+#define CANXL_MAX_DLC 2047
+#define CANXL_MAX_DLC_MASK 0x07FF
+#define CANXL_MIN_DLEN 1
+#define CANXL_MAX_DLEN 2048
+
 /**
  * struct can_frame - Classical CAN frame structure (aka CAN 2.0B)
  * @can_id:   CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
@@ -141,8 +154,8 @@ struct can_frame {
  * When this is done the former differentiation via CAN_MTU / CANFD_MTU gets
  * lost. CANFD_FDF allows programmers to mark CAN FD frames in the case of
  * using struct canfd_frame for mixed CAN / CAN FD content (dual use).
- * N.B. the Kernel APIs do NOT provide mixed CAN / CAN FD content inside of
- * struct canfd_frame therefore the CANFD_FDF flag is disregarded by Linux.
+ * Since the introduction of CAN XL the CANFD_FDF flag is set in all CAN FD
+ * frame structures provided by the CAN subsystem of the Linux kernel.
  */
 #define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
 #define CANFD_ESI 0x02 /* error state indicator of the transmitting node */
@@ -166,8 +179,46 @@ struct canfd_frame {
 	__u8    data[CANFD_MAX_DLEN] __attribute__((aligned(8)));
 };
 
+/*
+ * defined bits for canxl_frame.flags
+ *
+ * The canxl_frame.flags element contains two bits CANXL_XLF and CANXL_SEC
+ * and shares the relative position of the struct can[fd]_frame.len element.
+ * The CANXL_XLF bit ALWAYS needs to be set to indicate a valid CAN XL frame.
+ * As a side effect setting this bit intentionally breaks the length checks
+ * for Classical CAN and CAN FD frames.
+ *
+ * Undefined bits in canxl_frame.flags are reserved and shall be set to zero.
+ */
+#define CANXL_XLF 0x80 /* mandatory CAN XL frame flag (must always be set!) */
+#define CANXL_SEC 0x01 /* Simple Extended Content (security/segmentation) */
+
+/**
+ * struct canxl_frame - CAN with e'X'tended frame 'L'ength frame structure
+ * @prio:  11 bit arbitration priority with zero'ed CAN_*_FLAG flags
+ * @flags: additional flags for CAN XL
+ * @sdt:   SDU (service data unit) type
+ * @len:   frame payload length in byte (CANXL_MIN_DLEN .. CANXL_MAX_DLEN)
+ * @af:    acceptance field
+ * @data:  CAN XL frame payload (CANXL_MIN_DLEN .. CANXL_MAX_DLEN byte)
+ *
+ * @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) */
+	__u8    flags; /* additional flags for CAN XL */
+	__u8    sdt;   /* SDU (service data unit) type */
+	__u16   len;   /* frame payload length in byte */
+	__u32   af;    /* acceptance field */
+	__u8    data[CANXL_MAX_DLEN];
+};
+
 #define CAN_MTU		(sizeof(struct can_frame))
 #define CANFD_MTU	(sizeof(struct canfd_frame))
+#define CANXL_MTU	(sizeof(struct canxl_frame))
+#define CANXL_HDR_SIZE	(offsetof(struct canxl_frame, data))
+#define CANXL_MIN_MTU	(CANXL_HDR_SIZE + 64)
+#define CANXL_MAX_MTU	CANXL_MTU
 
 /* particular protocols of the protocol family PF_CAN */
 #define CAN_RAW		1 /* RAW sockets */

include/uapi/linux/can/raw.h

@@ -62,6 +62,7 @@ enum {
 	CAN_RAW_RECV_OWN_MSGS,	/* receive my own msgs (default:off) */
 	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) */
 };
 
 #endif /* !_UAPI_CAN_RAW_H */

include/uapi/linux/if_ether.h

@@ -138,6 +138,7 @@
 #define ETH_P_LOCALTALK 0x0009		/* Localtalk pseudo type 	*/
 #define ETH_P_CAN	0x000C		/* CAN: Controller Area Network */
 #define ETH_P_CANFD	0x000D		/* CANFD: CAN flexible data rate*/
+#define ETH_P_CANXL	0x000E		/* CANXL: eXtended frame Length */
 #define ETH_P_PPPTALK	0x0010		/* Dummy type for Atalk over PPP*/
 #define ETH_P_TR_802_2	0x0011		/* 802.2 frames 		*/
 #define ETH_P_MOBITEX	0x0015		/* Mobitex (kaz@cafe.net)	*/

net/can/af_can.c

@@ -199,27 +199,26 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
 int can_send(struct sk_buff *skb, int loop)
 {
 	struct sk_buff *newskb = NULL;
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
 	int err = -EINVAL;
 
-	if (skb->len == CAN_MTU) {
+	if (can_is_canxl_skb(skb)) {
+		skb->protocol = htons(ETH_P_CANXL);
+	} else if (can_is_can_skb(skb)) {
 		skb->protocol = htons(ETH_P_CAN);
-		if (unlikely(cfd->len > CAN_MAX_DLEN))
-			goto inval_skb;
-	} else if (skb->len == CANFD_MTU) {
+	} else if (can_is_canfd_skb(skb)) {
+		struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
 		skb->protocol = htons(ETH_P_CANFD);
-		if (unlikely(cfd->len > CANFD_MAX_DLEN))
-			goto inval_skb;
+
+		/* set CAN FD flag for CAN FD frames by default */
+		cfd->flags |= CANFD_FDF;
 	} else {
 		goto inval_skb;
 	}
 
-	/* Make sure the CAN frame can pass the selected CAN netdevice.
-	 * As structs can_frame and canfd_frame are similar, we can provide
-	 * CAN FD frames to legacy CAN drivers as long as the length is <= 8
-	 */
-	if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {
+	/* Make sure the CAN frame can pass the selected CAN netdevice. */
+	if (unlikely(skb->len > skb->dev->mtu)) {
 		err = -EMSGSIZE;
 		goto inval_skb;
 	}
@@ -678,53 +677,46 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev)
 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
 		   struct packet_type *pt, struct net_device *orig_dev)
 {
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
-
-	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU)) {
+	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_can_skb(skb)))) {
 		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
-		goto free_skb;
-	}
 
-	/* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */
-	if (unlikely(cfd->len > CAN_MAX_DLEN)) {
-		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d, datalen %d\n",
-			     dev->type, skb->len, cfd->len);
-		goto free_skb;
+		kfree_skb(skb);
+		return NET_RX_DROP;
 	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;
-
-free_skb:
-	kfree_skb(skb);
-	return NET_RX_DROP;
 }
 
 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
 		     struct packet_type *pt, struct net_device *orig_dev)
 {
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
-
-	if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU)) {
+	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canfd_skb(skb)))) {
 		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
-		goto free_skb;
-	}
 
-	/* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */
-	if (unlikely(cfd->len > CANFD_MAX_DLEN)) {
-		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d, datalen %d\n",
-			     dev->type, skb->len, cfd->len);
-		goto free_skb;
+		kfree_skb(skb);
+		return NET_RX_DROP;
 	}
 
 	can_receive(skb, dev);
 	return NET_RX_SUCCESS;
+}
+
+static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
+		     struct packet_type *pt, struct net_device *orig_dev)
+{
+	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canxl_skb(skb)))) {
+		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
+			     dev->type, skb->len);
 
-free_skb:
 		kfree_skb(skb);
 		return NET_RX_DROP;
+	}
+
+	can_receive(skb, dev);
+	return NET_RX_SUCCESS;
 }
 
 /* af_can protocol functions */
@@ -851,6 +843,11 @@ static struct packet_type canfd_packet __read_mostly = {
 	.func = canfd_rcv,
 };
 
+static struct packet_type canxl_packet __read_mostly = {
+	.type = cpu_to_be16(ETH_P_CANXL),
+	.func = canxl_rcv,
+};
+
 static const struct net_proto_family can_family_ops = {
 	.family = PF_CAN,
 	.create = can_create,
@@ -890,6 +887,7 @@ static __init int can_init(void)
 
 	dev_add_pack(&can_packet);
 	dev_add_pack(&canfd_packet);
+	dev_add_pack(&canxl_packet);
 
 	return 0;
 

net/can/bcm.c

@@ -648,8 +648,13 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data)
 		return;
 
 	/* make sure to handle the correct frame type (CAN / CAN FD) */
-	if (skb->len != op->cfsiz)
+	if (op->flags & CAN_FD_FRAME) {
+		if (!can_is_canfd_skb(skb))
+			return;
+	} else {
+		if (!can_is_can_skb(skb))
 			return;
+	}
 
 	/* disable timeout */
 	hrtimer_cancel(&op->timer);

net/can/gw.c

@@ -463,10 +463,10 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
 
 	/* process strictly Classic CAN or CAN FD frames */
 	if (gwj->flags & CGW_FLAGS_CAN_FD) {
-		if (skb->len != CANFD_MTU)
+		if (!can_is_canfd_skb(skb))
 			return;
 	} else {
-		if (skb->len != CAN_MTU)
+		if (!can_is_can_skb(skb))
 			return;
 	}
 

net/can/isotp.c

@@ -669,7 +669,7 @@ static void isotp_rcv(struct sk_buff *skb, void *data)
 		if (cf->len <= CAN_MAX_DLEN) {
 			isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
 		} else {
-			if (skb->len == CANFD_MTU) {
+			if (can_is_canfd_skb(skb)) {
 				/* We have a CAN FD frame and CAN_DL is greater than 8:
 				 * Only frames with the SF_DL == 0 ESC value are valid.
 				 *

net/can/j1939/main.c

@@ -42,6 +42,10 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data)
 	struct j1939_sk_buff_cb *skcb, *iskcb;
 	struct can_frame *cf;
 
+	/* make sure we only get Classical CAN frames */
+	if (!can_is_can_skb(iskb))
+		return;
+
 	/* create a copy of the skb
 	 * j1939 only delivers the real data bytes,
 	 * the header goes into sockaddr.

net/can/raw.c

@@ -50,6 +50,7 @@
 #include <linux/skbuff.h>
 #include <linux/can.h>
 #include <linux/can/core.h>
+#include <linux/can/dev.h> /* for can_is_canxl_dev_mtu() */
 #include <linux/can/skb.h>
 #include <linux/can/raw.h>
 #include <net/sock.h>
@@ -87,6 +88,7 @@ struct raw_sock {
 	int loopback;
 	int recv_own_msgs;
 	int fd_frames;
+	int xl_frames;
 	int join_filters;
 	int count;                 /* number of active filters */
 	struct can_filter dfilter; /* default/single filter */
@@ -129,8 +131,9 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	if (!ro->recv_own_msgs && oskb->sk == sk)
 		return;
 
-	/* do not pass non-CAN2.0 frames to a legacy socket */
-	if (!ro->fd_frames && oskb->len != CAN_MTU)
+	/* make sure to not pass oversized frames to the socket */
+	if ((can_is_canfd_skb(oskb) && !ro->fd_frames && !ro->xl_frames) ||
+	    (can_is_canxl_skb(oskb) && !ro->xl_frames))
 		return;
 
 	/* eliminate multiple filter matches for the same skb */
@@ -345,6 +348,7 @@ static int raw_init(struct sock *sk)
 	ro->loopback         = 1;
 	ro->recv_own_msgs    = 0;
 	ro->fd_frames        = 0;
+	ro->xl_frames        = 0;
 	ro->join_filters     = 0;
 
 	/* alloc_percpu provides zero'ed memory */
@@ -668,6 +672,15 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
 
 		break;
 
+	case CAN_RAW_XL_FRAMES:
+		if (optlen != sizeof(ro->xl_frames))
+			return -EINVAL;
+
+		if (copy_from_sockptr(&ro->xl_frames, optval, optlen))
+			return -EFAULT;
+
+		break;
+
 	case CAN_RAW_JOIN_FILTERS:
 		if (optlen != sizeof(ro->join_filters))
 			return -EINVAL;
@@ -750,6 +763,12 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
 		val = &ro->fd_frames;
 		break;
 
+	case CAN_RAW_XL_FRAMES:
+		if (len > sizeof(int))
+			len = sizeof(int);
+		val = &ro->xl_frames;
+		break;
+
 	case CAN_RAW_JOIN_FILTERS:
 		if (len > sizeof(int))
 			len = sizeof(int);
@@ -775,7 +794,11 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	struct sk_buff *skb;
 	struct net_device *dev;
 	int ifindex;
-	int err;
+	int err = -EINVAL;
+
+	/* check for valid CAN frame sizes */
+	if (size < CANXL_HDR_SIZE + CANXL_MIN_DLEN || size > CANXL_MTU)
+		return -EINVAL;
 
 	if (msg->msg_name) {
 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
@@ -795,15 +818,6 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	if (!dev)
 		return -ENXIO;
 
-	err = -EINVAL;
-	if (ro->fd_frames && dev->mtu == CANFD_MTU) {
-		if (unlikely(size != CANFD_MTU && size != CAN_MTU))
-			goto put_dev;
-	} else {
-		if (unlikely(size != CAN_MTU))
-			goto put_dev;
-	}
-
 	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
 				  msg->msg_flags & MSG_DONTWAIT, &err);
 	if (!skb)
@@ -813,10 +827,27 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	can_skb_prv(skb)->ifindex = dev->ifindex;
 	can_skb_prv(skb)->skbcnt = 0;
 
+	/* fill the skb before testing for valid CAN frames */
 	err = memcpy_from_msg(skb_put(skb, size), msg, size);
 	if (err < 0)
 		goto free_skb;
 
+	err = -EINVAL;
+	if (ro->xl_frames && can_is_canxl_dev_mtu(dev->mtu)) {
+		/* CAN XL, CAN FD and Classical CAN */
+		if (!can_is_canxl_skb(skb) && !can_is_canfd_skb(skb) &&
+		    !can_is_can_skb(skb))
+			goto free_skb;
+	} else if (ro->fd_frames && dev->mtu == CANFD_MTU) {
+		/* CAN FD and Classical CAN */
+		if (!can_is_canfd_skb(skb) && !can_is_can_skb(skb))
+			goto free_skb;
+	} else {
+		/* Classical CAN */
+		if (!can_is_can_skb(skb))
+			goto free_skb;
+	}
+
 	sockcm_init(&sockc, sk);
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(sk, msg, &sockc);