On Mon, May 14, 2018 at 04:54:36PM -0700, William Tu wrote:
> Before the patch, the erspan BSO bit (Bad/Short/Oversized) is not
> handled. BSO has 4 possible values:
> 00 --> Good frame with no error, or unknown integrity
> 11 --> Payload is a Bad Frame with CRC or Alignment Error
> 01 --> Payload is a Short Frame
> 10 --> Payload is an Oversized Frame
>
> Based the short/oversized definitions in RFC1757, the patch sets
> the bso bit based on the mirrored packet's size.
>
> Reported-by: Xiaoyan Jin <xiaoy...@vmware.com>
> Signed-off-by: William Tu <u9012...@gmail.com>
> ---
> include/net/erspan.h | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/include/net/erspan.h b/include/net/erspan.h
> index d044aa60cc76..5eb95f78ad45 100644
> --- a/include/net/erspan.h
> +++ b/include/net/erspan.h
> @@ -219,6 +219,30 @@ static inline __be32 erspan_get_timestamp(void)
> return htonl((u32)h_usecs);
> }
>
> +/* ERSPAN BSO (Bad/Short/Oversized)
> + * 00b --> Good frame with no error, or unknown integrity
> + * 01b --> Payload is a Short Frame
> + * 10b --> Payload is an Oversized Frame
> + * 11b --> Payload is a Bad Frame with CRC or Alignment Error
> + */
> +enum erspan_bso {
> + BSO_NOERROR,
> + BSO_SHORT,
> + BSO_OVERSIZED,
> + BSO_BAD,
> +};
If we are relying on the values perhaps this would be clearer
BSO_NOERROR = 0x00,
BSO_SHORT = 0x01,
BSO_OVERSIZED = 0x02,
BSO_BAD = 0x03,
> +
> +static inline u8 erspan_detect_bso(struct sk_buff *skb)
> +{
> + if (skb->len < ETH_ZLEN)
> + return BSO_SHORT;
> +
> + if (skb->len > ETH_FRAME_LEN)
> + return BSO_OVERSIZED;
> +
> + return BSO_NOERROR;
> +}
Without having much contextual knowledge around this patch; should we be
doing some check on CRC or alignment (at some stage)? Having BSO_BAD
seems to imply so?
Hope this helps,
Tobin.
