Subject: Re: [PATCH RESEND bpf-next 13/15] selftests/bpf: Allow VLAN packets in xdp_hw_metadata

From: Stanislav Fomichev <[email-masked]>
Date: Fri, 12 May 2023 11:33:34 -0700

On 05/12, Larysa Zaremba wrote:
> Make VLAN c-tag and s-tag XDP hint testing more convenient
> by not skipping VLAN-ed packets.
> 
> Allow both 802.1ad and 802.1Q headers.

Can we also extend non-hw test? That should require adding metadata
handlers to veth to extract relevant parts from skb + update ip link
commands to add vlan id. Should be relatively easy to do?

> 
> Signed-off-by: Larysa Zaremba <[email-masked]>
> ---
>  tools/testing/selftests/bpf/progs/xdp_hw_metadata.c | 9 ++++++++-
>  tools/testing/selftests/bpf/xdp_metadata.h          | 8 ++++++++
>  2 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> index b2dfd7066c6e..f95f82a8b449 100644
> --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> @@ -26,15 +26,22 @@ int rx(struct xdp_md *ctx)
>  {
>  	void *data, *data_meta, *data_end;
>  	struct ipv6hdr *ip6h = NULL;
> -	struct ethhdr *eth = NULL;
>  	struct udphdr *udp = NULL;
>  	struct iphdr *iph = NULL;
>  	struct xdp_meta *meta;
> +	struct ethhdr *eth;
>  	int err;
>  
>  	data = (void *)(long)ctx->data;
>  	data_end = (void *)(long)ctx->data_end;
>  	eth = data;
> +
> +	if (eth + 1 < data_end && eth->h_proto == bpf_htons(ETH_P_8021AD))
> +		eth = (void *)eth + sizeof(struct vlan_hdr);
> +
> +	if (eth + 1 < data_end && eth->h_proto == bpf_htons(ETH_P_8021Q))
> +		eth = (void *)eth + sizeof(struct vlan_hdr);
> +
>  	if (eth + 1 < data_end) {
>  		if (eth->h_proto == bpf_htons(ETH_P_IP)) {
>  			iph = (void *)(eth + 1);
> diff --git a/tools/testing/selftests/bpf/xdp_metadata.h b/tools/testing/selftests/bpf/xdp_metadata.h
> index 938a729bd307..6664893c2c77 100644
> --- a/tools/testing/selftests/bpf/xdp_metadata.h
> +++ b/tools/testing/selftests/bpf/xdp_metadata.h
> @@ -9,6 +9,14 @@
>  #define ETH_P_IPV6 0x86DD
>  #endif
>  
> +#ifndef ETH_P_8021Q
> +#define ETH_P_8021Q 0x8100
> +#endif
> +
> +#ifndef ETH_P_8021AD
> +#define ETH_P_8021AD 0x88A8
> +#endif
> +
>  struct xdp_meta {
>  	__u64 rx_timestamp;
>  	__u64 xdp_timestamp;
> -- 
> 2.35.3
>