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

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/xdp_metadata.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/xdp_metadata.c
Extension
.c
Size
2783 bytes
Lines
112
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

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));
	if (ret != 0)
		return XDP_DROP;

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

	if (data_meta + sizeof(struct xdp_meta) > data)
		return XDP_DROP;

	meta = data_meta;

	/* Export metadata. */

	/* We expect veth bpf_xdp_metadata_rx_timestamp to return 0 HW
	 * timestamp, so put some non-zero value into AF_XDP frame for
	 * the userspace.
	 */
	bpf_xdp_metadata_rx_timestamp(ctx, &timestamp);
	if (timestamp == 0)
		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_proto,
				     &meta->rx_vlan_tci);

	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
}

SEC("xdp")
int redirect(struct xdp_md *ctx)
{
	return bpf_redirect_map(&dev_map, ctx->rx_queue_index, XDP_PASS);
}

char _license[] SEC("license") = "GPL";

Annotation

Implementation Notes