Re: [dpdk-dev] [dpdk-stable] [PATCH 1/4] net/tap: fix Rx cksum flags on IP options packets

[Olivier Matz <olivier.matz@6wind.com>]

Hi Ferruh, Andrew,

On Tue, Jun 08, 2021 at 01:13:59PM +0300, Andrew Rybchenko wrote:
> On 4/30/21 5:48 PM, Ferruh Yigit wrote:
> > On 4/27/2021 2:57 PM, Olivier Matz wrote:
> >> When packet type is IPV4_EXT, the checksum is always marked as good in
> >> the mbuf offload flags.
> >>
> >> Since we know the header lengths, we can easily call
> >> rte_ipv4_udptcp_cksum() in this case too.
> >>
> >> Fixes: 8ae3023387e9 ("net/tap: add Rx/Tx checksum offload support")
> >> Cc: stable@dpdk.org
> >>
> >> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> >> ---
> >>  drivers/net/tap/rte_eth_tap.c | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> >> index 68baa18523..e7b185a4b5 100644
> >> --- a/drivers/net/tap/rte_eth_tap.c
> >> +++ b/drivers/net/tap/rte_eth_tap.c
> >> @@ -350,7 +350,7 @@ tap_verify_csum(struct rte_mbuf *mbuf)
> >>  		/* Don't verify checksum for multi-segment packets. */
> >>  		if (mbuf->nb_segs > 1)
> >>  			return;
> >> -		if (l3 == RTE_PTYPE_L3_IPV4) {
> >> +		if (l3 == RTE_PTYPE_L3_IPV4 || l3 == RTE_PTYPE_L3_IPV4_EXT) {
> > 
> > Should we take 'RTE_PTYPE_L3_IPV4_EXT_UNKNOWN' into account?
> 
> I think we should.

I think 'RTE_PTYPE_L3_IPV4_EXT_UNKNOWN' cannot happen here:

- mbuf->packet_type is generated by rte_net_get_ptype(), which cannot
  return 'RTE_PTYPE_L3_IPV4_EXT_UNKNOWN'
- right above this code, we already returned if l3 is not in
  (RTE_PTYPE_L3_IPV4, RTE_PTYPE_L3_IPV4_EXT, RTE_PTYPE_L3_IPV6)

> > 
> >>  			if (l4 == RTE_PTYPE_L4_UDP) {
> >>  				udp_hdr = (struct rte_udp_hdr *)l4_hdr;
> >>  				if (udp_hdr->dgram_cksum == 0) {
> >> @@ -364,7 +364,7 @@ tap_verify_csum(struct rte_mbuf *mbuf)
> >>  				}
> >>  			}
> >>  			cksum = ~rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr);
> >> -		} else if (l3 == RTE_PTYPE_L3_IPV6) {
> >> +		} else { /* l3 == RTE_PTYPE_L3_IPV6, checked above */
> >>  			cksum = ~rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr);
> >>  		}
> >>  		mbuf->ol_flags |= cksum ?
> >>
>