Re: [dpdk-dev] [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel packets

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Ivan Malov <ivan.malov@oktetlabs.ru>
> Sent: Friday, September 17, 2021 2:50 AM
> To: dev@dpdk.org
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org; Andrew
> Rybchenko <andrew.rybchenko@oktetlabs.ru>; Xia, Chenbo <chenbo.xia@intel.com>;
> Yuanhan Liu <yuanhan.liu@linux.intel.com>; Olivier Matz
> <olivier.matz@6wind.com>
> Subject: [PATCH v2] net/virtio: handle Tx checksums correctly for tunnel
> packets
> 
> Tx prepare method calls rte_net_intel_cksum_prepare(), which
> handles tunnel packets correctly, but Tx burst path does not
> take tunnel presence into account when computing the offsets.
> 
> Fixes: 58169a9c8153 ("net/virtio: support Tx checksum offload")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>  drivers/net/virtio/virtqueue.h | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> index 03957b2bd0..b83ff32efb 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -620,19 +620,21 @@ static inline void
>  virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
>  {
>  	uint64_t csum_l4 = cookie->ol_flags & PKT_TX_L4_MASK;
> +	uint16_t o_l23_len = (cookie->ol_flags & PKT_TX_TUNNEL_MASK) ?
> +			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
> 
>  	if (cookie->ol_flags & PKT_TX_TCP_SEG)
>  		csum_l4 |= PKT_TX_TCP_CKSUM;
> 
>  	switch (csum_l4) {
>  	case PKT_TX_UDP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
> 
>  	case PKT_TX_TCP_CKSUM:
> -		hdr->csum_start = cookie->l2_len + cookie->l3_len;
> +		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
>  		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
>  		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
>  		break;
> @@ -650,7 +652,8 @@ virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct
> rte_mbuf *cookie)
>  			VIRTIO_NET_HDR_GSO_TCPV6 :
>  			VIRTIO_NET_HDR_GSO_TCPV4;
>  		hdr->gso_size = cookie->tso_segsz;
> -		hdr->hdr_len = cookie->l2_len + cookie->l3_len + cookie->l4_len;
> +		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
> +			       cookie->l4_len;
>  	} else {
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
>  		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
> --
> 2.20.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>