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

[Thomas Monjalon <thomas@monjalon.net>]

09/03/2021 10:01, Andrew Rybchenko:
> 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.

+1

I think the only drawback of this solution is for HW giving a global
check status without knowing which header is valid or invalid.