selftests/bpf: Add selftest support for bpf_xdp_metadata_rx_checksum

Introduce support to xdp_metadata selftest for bpf_xdp_metadata_rx_checksum
kfunc.

Signed-off-by: Lorenzo Bianconi <[email protected]>

Author: LorenzoBianconi

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

@@ -258,6 +258,7 @@ static void refill_rx(struct xsk *xsk, __u64 addr)
 
 static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp)
 {
+	__u8 ip_summed = sent_from_af_xdp ? XDP_CHECKSUM_NONE : XDP_CHECKSUM_PARTIAL;
 	const struct xdp_desc *rx_desc;
 	struct pollfd fds = {};
 	struct xdp_meta *meta;
@@ -310,6 +311,12 @@ static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp)
 	if (!ASSERT_NEQ(meta->rx_hash, 0, "rx_hash"))
 		return -1;
 
+	if (!ASSERT_EQ(meta->ip_summed, ip_summed, "rx_ip_summed"))
+		return -1;
+
+	if (!ASSERT_EQ(meta->cksum_meta, 0, "rx_cksum_meta"))
+		return -1;
+
 	if (!sent_from_af_xdp) {
 		if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type"))
 			return -1;

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

@@ -98,6 +98,7 @@ int rx(struct xdp_md *ctx)
 	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);
+	bpf_xdp_metadata_rx_checksum(ctx, &meta->ip_summed, &meta->cksum_meta);
 
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }

tools/testing/selftests/bpf/xdp_metadata.h

@@ -30,6 +30,11 @@ enum xdp_meta_field {
 	XDP_META_FIELD_VLAN_TAG	= BIT(2),
 };
 
+#define XDP_CHECKSUM_NONE		0
+#define XDP_CHECKSUM_UNNECESSARY	1
+#define XDP_CHECKSUM_COMPLETE		2
+#define XDP_CHECKSUM_PARTIAL		3
+
 struct xdp_meta {
 	union {
 		__u64 rx_timestamp;
@@ -48,5 +53,9 @@ struct xdp_meta {
 		};
 		__s32 rx_vlan_tag_err;
 	};
+	struct {
+		__u8 ip_summed;
+		__u32 cksum_meta;
+	};
 	enum xdp_meta_field hint_valid;
 };