On Tue. 12 Jul. 2022 at 03:44, Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote:
> Enable the PF_CAN infrastructure to handle CAN XL frames. A new ethernet
> protocol type ETH_P_CANXL is defined to tag skbuffs containing the CAN XL
> frame data structure.
>
> As the length information is now a uint16 value for CAN XL a new helper
> function can_get_data_len() is introduced to retrieve the data length
> from all types of CAN frames.
>
> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
> ---
> include/linux/can/skb.h | 14 ++++++++++
> include/uapi/linux/if_ether.h | 1 +
> net/can/af_can.c | 49 +++++++++++++++++++++++++++++------
> 3 files changed, 56 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
> index 182749e858b3..d043bc4afd6d 100644
> --- a/include/linux/can/skb.h
> +++ b/include/linux/can/skb.h
> @@ -101,6 +101,20 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb)
> {
> /* the CAN specific type of skb is identified by its data length */
> return skb->len == CANFD_MTU;
> }
>
> +/* get data length inside of CAN frame for all frame types */> +static inline unsigned int can_get_data_len(struct sk_buff *skb)
> +{
> + if(skb->len == CANXL_MTU) {
> + const struct canxl_frame *cfx = (struct canxl_frame *)skb->data;
> +
> + return cfx->len;
> + } else {
> + const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
> +
> + return cfd->len;
> + }
> +}
What about the RTR frames?
If there are cases in which we intentionally want the declared length
and not the actual length, it might be good to have two distinct
helper functions.
/* get data length inside of CAN frame for all frame types. For
* RTR frames, return zero. */
static inline unsigned int can_get_actual_len(struct sk_buff *skb)
{
const struct canxl_frame *cfx = (struct canxl_frame *)skb->data;
const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
if (skb->len == CANXL_MTU)
return cfx->len;
/* RTR frames have an actual length of zero */
if (skb->len == CAN_MTU && cfd->flags & CAN_RTR_FLAG)
return 0;
return cfd->len;
}
/* get data length inside of CAN frame for all frame types. For
* RTR frames, return requested length. */
static inline unsigned int can_get_declared_len(struct sk_buff *skb)
{
const struct canxl_frame *cfx = (struct canxl_frame *)skb->data;
const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
if (skb->len == CANXL_MTU)
return cfx->len;
return cfd->len;
}
> +
> #endif /* !_CAN_SKB_H */
> diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
> index d370165bc621..69e0457eb200 100644
> --- a/include/uapi/linux/if_ether.h
> +++ b/include/uapi/linux/if_ether.h
> @@ -136,10 +136,11 @@
> #define ETH_P_WAN_PPP 0x0007 /* Dummy type for WAN PPP frames*/
> #define ETH_P_PPP_MP 0x0008 /* Dummy type for PPP MP frames */
> #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@xxxxxxxx) */
> #define ETH_P_CONTROL 0x0016 /* Card specific control frames */
> #define ETH_P_IRDA 0x0017 /* Linux-IrDA */
> diff --git a/net/can/af_can.c b/net/can/af_can.c
> index 1fb49d51b25d..2c9f48aa5f1f 100644
> --- a/net/can/af_can.c
> +++ b/net/can/af_can.c
> @@ -197,31 +197,32 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
> * -EINVAL when the skb->data does not contain a valid CAN frame
> */
> int can_send(struct sk_buff *skb, int loop)
> {
> struct sk_buff *newskb = NULL;
> - struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
> + unsigned int len = can_get_data_len(skb);
> struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
> int err = -EINVAL;
>
> if (skb->len == CAN_MTU) {
> skb->protocol = htons(ETH_P_CAN);
> - if (unlikely(cfd->len > CAN_MAX_DLEN))
> + if (unlikely(len > CAN_MAX_DLEN))
> goto inval_skb;
> } else if (skb->len == CANFD_MTU) {
> skb->protocol = htons(ETH_P_CANFD);
> - if (unlikely(cfd->len > CANFD_MAX_DLEN))
> + if (unlikely(len > CANFD_MAX_DLEN))
> + goto inval_skb;
> + } else if (skb->len == CANXL_MTU) {
> + skb->protocol = htons(ETH_P_CANXL);
> + if (unlikely(len > CANXL_MAX_DLEN || len == 0))
> goto inval_skb;
> } 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;
> }
>
> if (unlikely(skb->dev->type != ARPHRD_CAN)) {
> @@ -725,10 +726,36 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
> free_skb:
> kfree_skb(skb);
> return NET_RX_DROP;
> }
>
> +static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
> + struct packet_type *pt, struct net_device *orig_dev)
> +{
> + struct canxl_frame *cfx = (struct canxl_frame *)skb->data;
> +
> + if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANXL_MTU)) {
> + pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
> + dev->type, skb->len);
> + goto free_skb;
> + }
> +
> + /* This check is made separately since cfx->len would be uninitialized if skb->len = 0. */
> + if (unlikely(cfx->len > CANXL_MAX_DLEN || cfx->len == 0)) {
> + pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d, datalen %d\n",
> + dev->type, skb->len, cfx->len);
> + goto free_skb;
> + }
> +
> + can_receive(skb, dev);
> + return NET_RX_SUCCESS;
> +
> +free_skb:
> + kfree_skb(skb);
> + return NET_RX_DROP;
> +}
> +
> /* af_can protocol functions */
>
> /**
> * can_proto_register - register CAN transport protocol
> * @cp: pointer to CAN protocol structure
> @@ -849,10 +876,15 @@ static struct packet_type can_packet __read_mostly = {
> static struct packet_type canfd_packet __read_mostly = {
> .type = cpu_to_be16(ETH_P_CANFD),
> .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,
> .owner = THIS_MODULE,
> };
> @@ -888,10 +920,11 @@ static __init int can_init(void)
> if (err)
> goto out_sock;
>
> dev_add_pack(&can_packet);
> dev_add_pack(&canfd_packet);
> + dev_add_pack(&canxl_packet);
>
> return 0;
>
> out_sock:
> unregister_pernet_subsys(&can_pernet_ops);
> --
> 2.30.2
>
