Re: [dpdk-dev] [RFC] ethdev: add sanity packet checks

[Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>]

On 2/28/21 10:48 PM, Ori Kam wrote:
> Currently, DPDK application can offload the checksum check,
> and report it in the mbuf.
>
> However, this approach doesn't work if the traffic
> is offloaded and should not arrive to the application.
>
> This commit introduces rte flow item that enables
> matching on the checksum of the L3 and L4 layers,
> in addition to other checks that can determine if
> the packet is valid.
> some of those tests can be packet len, data len,
> unsupported flags, and so on.
>
> The full check is HW dependent.
>
> Signed-off-by: Ori Kam <orika@nvidia.com>

In general, I strongly dislike the approach. If such checks are required,
it must be done per item basis. I.e. we should add non-header boolean
flags to IPv4, TCP, UDP etc items. E.g.

struct rte_flow_item_ipv4 {
        struct rte_ipv4_hdr hdr; /**< IPv4 header definition. */
        bool hdr_checksum_valid;
};

Also it will allow to filter by packets with invalid checksum as well and
redirect to dedicated Rx path or drop and/or count etc.