[PATCH 2/2] selftests/bpf: validate rx_queue_index in xdp_metadata

[Siddharth C <siddharthcibi@icloud.com>]

From: Siddharth_Cibi <siddharthcibi@icloud.com>

Extend xdp_metadata selftest coverage to validate that
ctx->rx_queue_index is preserved and observable after XDP redirect
execution.

Capture rx_queue_index in metadata and assert that it matches the
expected queue during packet verification.

Signed-off-by: Siddharth_Cibi <siddharthcibi@icloud.com>
---
 tools/testing/selftests/bpf/prog_tests/xdp_metadata.c | 3 ++-
 tools/testing/selftests/bpf/progs/xdp_metadata.c      | 2 +-
 tools/testing/selftests/bpf/xdp_metadata.h            | 1 +
 3 files changed, 4 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 5c31054ad4a4..f8cabbbe7bb7 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -309,7 +309,8 @@ 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->rx_queue_index, QUEUE_ID, "rx_queue_index"))
+        	return -1;
 	if (!sent_from_af_xdp) {
 		if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type"))
 			return -1;
diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c
index 09bb8a038d52..62ae83860d7f 100644
--- a/tools/testing/selftests/bpf/progs/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c
@@ -98,7 +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);
-
+	meta->rx_queue_index = ctx->rx_queue_index;
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }
 
diff --git a/tools/testing/selftests/bpf/xdp_metadata.h b/tools/testing/selftests/bpf/xdp_metadata.h
index 87318ad1117a..1f0ae4c00091 100644
--- a/tools/testing/selftests/bpf/xdp_metadata.h
+++ b/tools/testing/selftests/bpf/xdp_metadata.h
@@ -49,4 +49,5 @@ struct xdp_meta {
 		__s32 rx_vlan_tag_err;
 	};
 	enum xdp_meta_field hint_valid;
+	__u32 rx_queue_index;
 };
-- 
2.53.0