Commit 5ffb260f authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
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selftests/bpf: Make sure we trigger metadata kfuncs for dst 8080 



xdp_metadata test is flaky sometimes:

  verify_xsk_metadata:FAIL:rx_hash_type unexpected rx_hash_type: actual 8 != expected 0

Where 8 means XDP_RSS_TYPE_L4_ANY and is exported from veth driver only when
'skb->l4_hash' condition is met. This makes me think that the program is
triggering again for some other packet.

Let's have a filter, similar to xdp_hw_metadata, where we trigger XDP kfuncs
only for UDP packets destined to port 8080.

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20231204174423.3460052-1-sdf@google.com
parent 5c399ae0

tools/testing/selftests/bpf/progs/xdp_metadata.c

+30 −1
Original line number Diff line number Diff line
@@ -27,11 +27,40 @@ extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash, 
SEC("xdp")

int rx(struct xdp_md *ctx)

{

	void *data, *data_meta;

	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;

	u64 timestamp = -1;

	int ret;



	data = (void *)(long)ctx->data;

	data_end = (void *)(long)ctx->data_end;

	eth = data;

	if (eth + 1 < data_end) {

		if (eth->h_proto == bpf_htons(ETH_P_IP)) {

			iph = (void *)(eth + 1);

			if (iph + 1 < data_end && iph->protocol == IPPROTO_UDP)

				udp = (void *)(iph + 1);

		}

		if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {

			ip6h = (void *)(eth + 1);

			if (ip6h + 1 < data_end && ip6h->nexthdr == IPPROTO_UDP)

				udp = (void *)(ip6h + 1);

		}

		if (udp && udp + 1 > data_end)

			udp = NULL;

	}



	if (!udp)

		return XDP_PASS;



	/* Forwarding UDP:8080 to AF_XDP */

	if (udp->dest != bpf_htons(8080))

		return XDP_PASS;



	/* Reserve enough for all custom metadata. */



	ret = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));