On Mon, 2024-05-06 at 20:08 +0300, Ilpo Järvinen wrote:
> 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??
I guess GFP_KERNEL but I'm not sure so I'll let gfp_any() decide for
netdev_get_by_index() too.
>
> > + 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.
OK
...
thanks
-- Christoph
