[PATCH net-next 16/27] can: raw: instantly reject unsupported CAN frames
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2025-11-26 12:01:24
Also in:
linux-can
Subsystem:
can network layer, the rest · Maintainers:
Oliver Hartkopp, Marc Kleine-Budde, Linus Torvalds
From: Oliver Hartkopp <socketcan@hartkopp.net> For real CAN interfaces the CAN_CTRLMODE_FD and CAN_CTRLMODE_XL control modes indicate whether an interface can handle those CAN FD/XL frames. In the case a CAN XL interface is configured in CANXL-only mode with disabled error-signalling neither CAN CC nor CAN FD frames can be sent. The checks are performed on CAN_RAW sockets to give an instant feedback to the user when writing unsupported CAN frames to the interface. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://patch.msgid.link/20251126-canxl-v8-16-e7e3eb74f889@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> --- net/can/raw.c | 54 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 46 insertions(+), 8 deletions(-)
diff --git a/net/can/raw.c b/net/can/raw.c
index f36a83d3447c..be1ef7cf4204 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c@@ -892,20 +892,58 @@ static void raw_put_canxl_vcid(struct raw_sock *ro, struct sk_buff *skb) } } -static unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu) +static inline bool raw_dev_cc_enabled(struct net_device *dev, + struct can_priv *priv) { - /* Classical CAN -> no checks for flags and device capabilities */ - if (can_is_can_skb(skb)) + /* The CANXL-only mode disables error-signalling on the CAN bus + * which is needed to send CAN CC/FD frames + */ + if (priv) + return !can_dev_in_xl_only_mode(priv); + + /* virtual CAN interfaces always support CAN CC */ + return true; +} + +static inline bool raw_dev_fd_enabled(struct net_device *dev, + struct can_priv *priv) +{ + /* check FD ctrlmode on real CAN interfaces */ + if (priv) + return (priv->ctrlmode & CAN_CTRLMODE_FD); + + /* check MTU for virtual CAN FD interfaces */ + return (READ_ONCE(dev->mtu) >= CANFD_MTU); +} + +static inline bool raw_dev_xl_enabled(struct net_device *dev, + struct can_priv *priv) +{ + /* check XL ctrlmode on real CAN interfaces */ + if (priv) + return (priv->ctrlmode & CAN_CTRLMODE_XL); + + /* check MTU for virtual CAN XL interfaces */ + return can_is_canxl_dev_mtu(READ_ONCE(dev->mtu)); +} + +static unsigned int raw_check_txframe(struct raw_sock *ro, struct sk_buff *skb, + struct net_device *dev) +{ + struct can_priv *priv = safe_candev_priv(dev); + + /* Classical CAN */ + if (can_is_can_skb(skb) && raw_dev_cc_enabled(dev, priv)) return CAN_MTU; - /* CAN FD -> needs to be enabled and a CAN FD or CAN XL device */ + /* CAN FD */ if (ro->fd_frames && can_is_canfd_skb(skb) && - (mtu == CANFD_MTU || can_is_canxl_dev_mtu(mtu))) + raw_dev_fd_enabled(dev, priv)) return CANFD_MTU; - /* CAN XL -> needs to be enabled and a CAN XL device */ + /* CAN XL */ if (ro->xl_frames && can_is_canxl_skb(skb) && - can_is_canxl_dev_mtu(mtu)) + raw_dev_xl_enabled(dev, priv)) return CANXL_MTU; return 0;
@@ -961,7 +999,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) err = -EINVAL; /* check for valid CAN (CC/FD/XL) frame content */ - txmtu = raw_check_txframe(ro, skb, READ_ONCE(dev->mtu)); + txmtu = raw_check_txframe(ro, skb, dev); if (!txmtu) goto free_skb;
--
2.51.0