Subject: Re: [PATCH bpf-next v3 20/21] selftests/bpf: Check VLAN tag and proto in xdp_metadata

From: Stanislav Fomichev <[email-masked]>
Date: Thu, 20 Jul 2023 15:14:15 -0700

On 07/19, Larysa Zaremba wrote:
> Verify, whether VLAN tag and proto are set correctly.
> 
> To simulate "stripped" VLAN tag on veth, send test packet from VLAN
> interface.
> 
> Signed-off-by: Larysa Zaremba <[email-masked]>

Acked-by: Stanislav Fomichev <[email-masked]>

> ---
>  .../selftests/bpf/prog_tests/xdp_metadata.c   | 22 +++++++++++++++++--
>  .../selftests/bpf/progs/xdp_metadata.c        |  4 ++++
>  2 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
> index 1877e5c6d6c7..6665cf0c59cc 100644
> --- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
> @@ -38,7 +38,15 @@
>  #define TX_MAC "00:00:00:00:00:01"
>  #define RX_MAC "00:00:00:00:00:02"
>  
> +#define VLAN_ID 59
> +#define VLAN_ID_STR "59"

I was looking whether we have some str(x) macro in the selftests,
but doesn't look like we have any...

> +#define VLAN_PROTO "802.1Q"
> +#define VLAN_PID htons(ETH_P_8021Q)
> +#define TX_NAME_VLAN TX_NAME "." VLAN_ID_STR
> +#define RX_NAME_VLAN RX_NAME "." VLAN_ID_STR
> +
>  #define XDP_RSS_TYPE_L4 BIT(3)
> +#define VLAN_VID_MASK 0xfff
>  
>  struct xsk {
>  	void *umem_area;
> @@ -215,6 +223,12 @@ static int verify_xsk_metadata(struct xsk *xsk)
>  	if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type"))
>  		return -1;
>  
> +	if (!ASSERT_EQ(meta->rx_vlan_tci & VLAN_VID_MASK, VLAN_ID, "rx_vlan_tci"))
> +		return -1;
> +
> +	if (!ASSERT_EQ(meta->rx_vlan_proto, VLAN_PID, "rx_vlan_proto"))
> +		return -1;
> +
>  	xsk_ring_cons__release(&xsk->rx, 1);
>  	refill_rx(xsk, comp_addr);
>  
> @@ -248,10 +262,14 @@ void test_xdp_metadata(void)
>  
>  	SYS(out, "ip link set dev " TX_NAME " address " TX_MAC);
>  	SYS(out, "ip link set dev " TX_NAME " up");
> -	SYS(out, "ip addr add " TX_ADDR "/" PREFIX_LEN " dev " TX_NAME);
> +
> +	SYS(out, "ip link add link " TX_NAME " " TX_NAME_VLAN
> +		 " type vlan proto " VLAN_PROTO " id " VLAN_ID_STR);
> +	SYS(out, "ip link set dev " TX_NAME_VLAN " up");
> +	SYS(out, "ip addr add " TX_ADDR "/" PREFIX_LEN " dev " TX_NAME_VLAN);
>  
>  	/* Avoid ARP calls */
> -	SYS(out, "ip -4 neigh add " RX_ADDR " lladdr " RX_MAC " dev " TX_NAME);
> +	SYS(out, "ip -4 neigh add " RX_ADDR " lladdr " RX_MAC " dev " TX_NAME_VLAN);
>  	close_netns(tok);
>  
>  	tok = open_netns(RX_NETNS_NAME);
> diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c
> index d151d406a123..d3111649170e 100644
> --- a/tools/testing/selftests/bpf/progs/xdp_metadata.c
> +++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c
> @@ -23,6 +23,9 @@ extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx,
>  					 __u64 *timestamp) __ksym;
>  extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
>  				    enum xdp_rss_hash_type *rss_type) __ksym;
> +extern int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
> +					__u16 *vlan_tci,
> +					__be16 *vlan_proto) __ksym;
>  
>  SEC("xdp")
>  int rx(struct xdp_md *ctx)
> @@ -57,6 +60,7 @@ int rx(struct xdp_md *ctx)
>  		meta->rx_timestamp = 1;
>  
>  	bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash, &meta->rx_hash_type);
> +	bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_tci, &meta->rx_vlan_proto);
>  
>  	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
>  }
> -- 
> 2.41.0
>