[PATCH bpf-next v4 20/21] selftests/bpf: Check VLAN tag and proto in xdp_metadata

[Larysa Zaremba <larysa.zaremba@xxxxxxxxx>]

Verify, whether VLAN tag and proto are set correctly.

To simulate "stripped" VLAN tag on veth, send test packet from VLAN
interface.

Also, add TO_STR() macro for convenience.

Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
 .../selftests/bpf/prog_tests/xdp_metadata.c   | 21 +++++++++++++++++--
 .../selftests/bpf/progs/xdp_metadata.c        |  5 +++++
 tools/testing/selftests/bpf/testing_helpers.h |  3 +++
 3 files changed, 27 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..61e1b073a4b2 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -38,7 +38,14 @@
 #define TX_MAC "00:00:00:00:00:01"
 #define RX_MAC "00:00:00:00:00:02"
 
+#define VLAN_ID 59
+#define VLAN_PROTO "802.1Q"
+#define VLAN_PID htons(ETH_P_8021Q)
+#define TX_NAME_VLAN TX_NAME "." TO_STR(VLAN_ID)
+#define RX_NAME_VLAN RX_NAME "." TO_STR(VLAN_ID)
+
 #define XDP_RSS_TYPE_L4 BIT(3)
+#define VLAN_VID_MASK 0xfff
 
 struct xsk {
 	void *umem_area;
@@ -215,6 +222,12 @@ 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 +261,14 @@ 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 " TO_STR(VLAN_ID));
+	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..f3db5cef4726 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 +60,8 @@ 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);
 }
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 5312323881b6..7e0f8543a3a4 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -8,6 +8,9 @@
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 
+#define __TO_STR(x) #x
+#define TO_STR(x) __TO_STR(x)
+
 int parse_num_list(const char *s, bool **set, int *set_len);
 __u32 link_info_prog_id(const struct bpf_link *link, struct bpf_link_info *info);
 int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
-- 
2.41.0