On Thu, 2 May 2024, Christoph Fritz wrote:
> Enhance CAN broadcast manager with RX_LIN_SETUP and RX_LIN_DELETE
> operations to setup automatic LIN frame responses in responder mode.
>
> Additionally, the patch introduces the LIN_EVENT_FRAME flag to
> setup event-triggered LIN frames.
>
> Signed-off-by: Christoph Fritz <christoph.fritz@xxxxxxxxx>
> ---
> include/uapi/linux/can/bcm.h | 5 ++-
> net/can/bcm.c | 74 +++++++++++++++++++++++++++++++++++-
> 2 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/can/bcm.h b/include/uapi/linux/can/bcm.h
> index f1e45f533a72c..c46268a114078 100644
> --- a/include/uapi/linux/can/bcm.h
> +++ b/include/uapi/linux/can/bcm.h
> @@ -86,7 +86,9 @@ enum {
> TX_EXPIRED, /* notification on performed transmissions (count=0) */
> RX_STATUS, /* reply to RX_READ request */
> RX_TIMEOUT, /* cyclic message is absent */
> - RX_CHANGED /* updated CAN frame (detected content change) */
> + RX_CHANGED, /* updated CAN frame (detected content change) */
> + RX_LIN_SETUP, /* create auto-response for LIN frame */
> + RX_LIN_DELETE, /* remove auto-response for LIN frame */
> };
>
> #define SETTIMER 0x0001
> @@ -101,5 +103,6 @@ enum {
> #define TX_RESET_MULTI_IDX 0x0200
> #define RX_RTR_FRAME 0x0400
> #define CAN_FD_FRAME 0x0800
> +#define LIN_EVENT_FRAME 0x1000
>
> #endif /* !_UAPI_CAN_BCM_H */
> diff --git a/net/can/bcm.c b/net/can/bcm.c
> index 27d5fcf0eac9d..a717e594234d1 100644
> --- a/net/can/bcm.c
> +++ b/net/can/bcm.c
> @@ -59,6 +59,7 @@
> #include <linux/can/bcm.h>
> #include <linux/slab.h>
> #include <net/sock.h>
> +#include <net/lin.h>
> #include <net/net_namespace.h>
>
> /*
> @@ -1330,6 +1331,59 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
> return cfsiz + MHSIZ;
> }
>
> +static int bcm_lin_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
> + int ifindex, struct sock *sk, int cfsiz, int is_active)
> +{
> + struct lin_responder_answer answ;
> + struct net_device *dev;
> + struct sk_buff *skb;
> + struct canfd_frame cf;
> + netdevice_tracker tracker;
> + size_t sz;
> + int ret;
> +
> + if (msg_head->nframes > 1)
> + return -EINVAL;
> +
> + if (!(msg_head->flags & CAN_FD_FRAME))
> + return -EINVAL;
> +
> + ret = memcpy_from_msg(&cf, msg, cfsiz);
> + if (ret < 0)
> + return ret;
> +
> + answ.lf.lin_id = cf.can_id & LIN_ID_MASK;
> + answ.is_active = is_active;
> + answ.is_event_frame = !!(msg_head->flags & LIN_EVENT_FRAME);
> + answ.event_associated_id = msg_head->can_id;
> + answ.lf.len = min(cf.len, LIN_MAX_DLEN);
> + memcpy(answ.lf.data, cf.data, answ.lf.len);
> + sz = min(sizeof(struct lin_responder_answer), sizeof(cf.data));
> + cf.can_id |= LIN_RXOFFLOAD_DATA_FLAG;
> + memcpy(cf.data, &answ, sz);
> +
> + dev = netdev_get_by_index(sock_net(sk), ifindex, &tracker, GFP_KERNEL);
> + if (!dev)
> + return -ENODEV;
> +
> + skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), gfp_any());
You just called the other function with GFP_KERNEL and you now need
gfp_any(). Which is correct??
> + if (!skb)
> + goto lin_out;
> +
> + can_skb_reserve(skb);
> + can_skb_prv(skb)->ifindex = dev->ifindex;
> + can_skb_prv(skb)->skbcnt = 0;
> + skb_put_data(skb, &cf, cfsiz);
> +
> + skb->dev = dev;
> + can_skb_set_owner(skb, sk);
> + ret = can_send(skb, 1); /* send with loopback */
> +
> +lin_out:
> + netdev_put(dev, &tracker);
> + return ret;
> +}
> +
> /*
> * bcm_sendmsg - process BCM commands (opcodes) from the userspace
> */
> @@ -1429,12 +1483,30 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
>
> case TX_SEND:
> /* we need exactly one CAN frame behind the msg head */
> - if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
> + if (msg_head.nframes != 1 || size != cfsiz + MHSIZ)
Unrelated style fix, doesn't belong to this patch.
> ret = -EINVAL;
> else
> ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
> break;
>
> + case RX_LIN_SETUP:
> + /* we need exactly one CAN frame behind the msg head */
> + if (msg_head.nframes != 1 || size != cfsiz + MHSIZ)
> + ret = -EINVAL;
> + else
> + ret = bcm_lin_setup(&msg_head, msg, ifindex, sk, cfsiz,
> + 1);
> + break;
> +
> + case RX_LIN_DELETE:
> + /* we need exactly one CAN frame behind the msg head */
> + if (msg_head.nframes != 1 || size != cfsiz + MHSIZ)
> + ret = -EINVAL;
> + else
> + ret = bcm_lin_setup(&msg_head, msg, ifindex, sk, cfsiz,
> + 0);
> + break;
> +
> default:
> ret = -EINVAL;
> break;
>
--
i.
