[PATCH bpf-next v3 2/2] selftests/bpf: xdp_metadata: check XDP_REDIRCT support for dev-bound progs

[Lorenzo Bianconi <lorenzo@kernel.org>]

Improve xdp_metadata bpf selftest in order to check it is possible for a
XDP dev-bound program to perform XDP_REDIRECT into a DEVMAP but it is still
not allowed to attach a XDP dev-bound program to a DEVMAP entry.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 .../selftests/bpf/prog_tests/xdp_metadata.c        | 22 +++++++++++++++++++++-
 tools/testing/selftests/bpf/progs/xdp_metadata.c   | 13 +++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index 3d47878ef6bfb55c236dc9df2c100fcc449f8de3..19f92affc2daa23fdd869554e7a0475b86350a4f 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
@@ -351,9 +351,10 @@ void test_xdp_metadata(void)
 	struct xdp_metadata2 *bpf_obj2 = NULL;
 	struct xdp_metadata *bpf_obj = NULL;
 	struct bpf_program *new_prog, *prog;
+	struct bpf_devmap_val devmap_e = {};
+	struct bpf_map *prog_arr, *devmap;
 	struct nstoken *tok = NULL;
 	__u32 queue_id = QUEUE_ID;
-	struct bpf_map *prog_arr;
 	struct xsk tx_xsk = {};
 	struct xsk rx_xsk = {};
 	__u32 val, key = 0;
@@ -409,6 +410,13 @@ void test_xdp_metadata(void)
 	bpf_program__set_ifindex(prog, rx_ifindex);
 	bpf_program__set_flags(prog, BPF_F_XDP_DEV_BOUND_ONLY);
 
+	/* Make sure we can load a dev-bound program that performs
+	 * XDP_REDIRECT into a devmap.
+	 */
+	new_prog = bpf_object__find_program_by_name(bpf_obj->obj, "redirect");
+	bpf_program__set_ifindex(new_prog, rx_ifindex);
+	bpf_program__set_flags(new_prog, BPF_F_XDP_DEV_BOUND_ONLY);
+
 	if (!ASSERT_OK(xdp_metadata__load(bpf_obj), "load skeleton"))
 		goto out;
 
@@ -423,6 +431,18 @@ void test_xdp_metadata(void)
 			"update prog_arr"))
 		goto out;
 
+	/* Make sure we can't add dev-bound programs to devmaps. */
+	devmap = bpf_object__find_map_by_name(bpf_obj->obj, "dev_map");
+	if (!ASSERT_OK_PTR(devmap, "no dev_map found"))
+		goto out;
+
+	devmap_e.bpf_prog.fd = val;
+	if (!ASSERT_ERR(bpf_map__update_elem(devmap, &key, sizeof(key),
+					     &devmap_e, sizeof(devmap_e),
+					     BPF_ANY),
+			"update dev_map"))
+		goto out;
+
 	/* Attach BPF program to RX interface. */
 
 	ret = bpf_xdp_attach(rx_ifindex,
diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c
index 31ca229bb3c0f182483334a4ab0bd204acae20f3..09bb8a038d528cf26c5b314cc927915ac2796bf0 100644
--- a/tools/testing/selftests/bpf/progs/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c
@@ -19,6 +19,13 @@ struct {
 	__type(value, __u32);
 } prog_arr SEC(".maps");
 
+struct {
+	__uint(type, BPF_MAP_TYPE_DEVMAP);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(struct bpf_devmap_val));
+	__uint(max_entries, 1);
+} dev_map SEC(".maps");
+
 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,
@@ -95,4 +102,10 @@ int rx(struct xdp_md *ctx)
 	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";

-- 
2.49.0