selftests/bpf: Add flags and VLAN hint to xdp_hw_metadata

Add VLAN hint to the xdp_hw_metadata program.

Also, to make metadata layout more straightforward, add flags field
to pass information about validity of every separate hint separately.

Acked-by: Stanislav Fomichev <[e-mail]>
Signed-off-by: Larysa Zaremba <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

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

···
 					 __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,
+					__be16 *vlan_proto,
+					__u16 *vlan_tci) __ksym;
 
 SEC("xdp.frags")
 int rx(struct xdp_md *ctx)
···
 		return XDP_PASS;
 	}
 
-	err = bpf_xdp_metadata_rx_timestamp(ctx, &meta->rx_timestamp);
-	if (!err)
-		meta->xdp_timestamp = bpf_ktime_get_tai_ns();
-	else
-		meta->rx_timestamp = 0; /* Used by AF_XDP as not avail signal */
+	meta->hint_valid = 0;
 
-	err = bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash, &meta->rx_hash_type);
-	if (err < 0)
-		meta->rx_hash_err = err; /* Used by AF_XDP as no hash signal */
+	meta->xdp_timestamp = bpf_ktime_get_tai_ns();
+	err = bpf_xdp_metadata_rx_timestamp(ctx, &meta->rx_timestamp);
+	if (err)
+		meta->rx_timestamp_err = err;
+	else
+		meta->hint_valid |= XDP_META_FIELD_TS;
+
+	err = bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash,
+				       &meta->rx_hash_type);
+	if (err)
+		meta->rx_hash_err = err;
+	else
+		meta->hint_valid |= XDP_META_FIELD_RSS;
+
+	err = bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto,
+					   &meta->rx_vlan_tci);
+	if (err)
+		meta->rx_vlan_tag_err = err;
+	else
+		meta->hint_valid |= XDP_META_FIELD_VLAN_TAG;
 
 	__sync_add_and_fetch(&pkts_redir, 1);
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);

tools/testing/selftests/bpf/xdp_hw_metadata.c

···
 #include "xsk.h"
 
 #include <error.h>
+#include <linux/kernel.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
 #include <linux/errqueue.h>
 #include <linux/if_link.h>
 #include <linux/net_tstamp.h>
···
 	       (double)delta / 1000);
 }
 
+#define VLAN_PRIO_MASK		GENMASK(15, 13) /* Priority Code Point */
+#define VLAN_DEI_MASK		GENMASK(12, 12) /* Drop Eligible Indicator */
+#define VLAN_VID_MASK		GENMASK(11, 0)	/* VLAN Identifier */
+static void print_vlan_tci(__u16 tag)
+{
+	__u16 vlan_id = FIELD_GET(VLAN_VID_MASK, tag);
+	__u8 pcp = FIELD_GET(VLAN_PRIO_MASK, tag);
+	bool dei = FIELD_GET(VLAN_DEI_MASK, tag);
+
+	printf("PCP=%u, DEI=%d, VID=0x%X\n", pcp, dei, vlan_id);
+}
+
 static void verify_xdp_metadata(void *data, clockid_t clock_id)
 {
 	struct xdp_meta *meta;
 
 	meta = data - sizeof(*meta);
 
-	if (meta->rx_hash_err < 0)
-		printf("No rx_hash err=%d\n", meta->rx_hash_err);
-	else
+	if (meta->hint_valid & XDP_META_FIELD_RSS)
 		printf("rx_hash: 0x%X with RSS type:0x%X\n",
 		       meta->rx_hash, meta->rx_hash_type);
+	else
+		printf("No rx_hash, err=%d\n", meta->rx_hash_err);
 
-	if (meta->rx_timestamp) {
+	if (meta->hint_valid & XDP_META_FIELD_TS) {
 		__u64 ref_tstamp = gettime(clock_id);
 
 		/* store received timestamps to calculate a delta at tx */
···
 		print_tstamp_delta("XDP RX-time", "User RX-time",
 				   meta->xdp_timestamp, ref_tstamp);
 	} else {
-		printf("No rx_timestamp\n");
+		printf("No rx_timestamp, err=%d\n", meta->rx_timestamp_err);
+	}
+
+	if (meta->hint_valid & XDP_META_FIELD_VLAN_TAG) {
+		printf("rx_vlan_proto: 0x%X\n", ntohs(meta->rx_vlan_proto));
+		printf("rx_vlan_tci: ");
+		print_vlan_tci(meta->rx_vlan_tci);
+	} else {
+		printf("No rx_vlan_tci or rx_vlan_proto, err=%d\n",
+		       meta->rx_vlan_tag_err);
 	}
 }
 

tools/testing/selftests/bpf/xdp_metadata.h

···
 #define ETH_P_8021AD 0x88A8
 #endif
 
+#ifndef BIT
+#define BIT(nr)			(1 << (nr))
+#endif
+
+/* Non-existent checksum status */
+#define XDP_CHECKSUM_MAGIC	BIT(2)
+
+enum xdp_meta_field {
+	XDP_META_FIELD_TS	= BIT(0),
+	XDP_META_FIELD_RSS	= BIT(1),
+	XDP_META_FIELD_VLAN_TAG	= BIT(2),
+};
+
 struct xdp_meta {
-	__u64 rx_timestamp;
+	union {
+		__u64 rx_timestamp;
+		__s32 rx_timestamp_err;
+	};
 	__u64 xdp_timestamp;
 	__u32 rx_hash;
 	union {
 		__u32 rx_hash_type;
 		__s32 rx_hash_err;
 	};
+	union {
+		struct {
+			__be16 rx_vlan_proto;
+			__u16 rx_vlan_tci;
+		};
+		__s32 rx_vlan_tag_err;
+	};
+	enum xdp_meta_field hint_valid;
 };