selftests/bpf: add test for bpf_xdp_query xdp-features support

Introduce a self-test to verify libbpf bpf_xdp_query capability to dump
the xdp-features supported by the device (lo and veth in this case).
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/534550318a2c883e174811683909544c63632f05.1675245258.git.lorenzo@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -4,10 +4,12 @@
 #include <net/if.h>
 #include <linux/if_ether.h>
 #include <linux/if_packet.h>
+#include <linux/if_link.h>
 #include <linux/ipv6.h>
 #include <linux/in6.h>
 #include <linux/udp.h>
 #include <bpf/bpf_endian.h>
+#include <uapi/linux/netdev.h>
 #include "test_xdp_do_redirect.skel.h"
 
 #define SYS(fmt, ...)						\
@@ -96,7 +98,7 @@ void test_xdp_do_redirect(void)
 	struct test_xdp_do_redirect *skel = NULL;
 	struct nstoken *nstoken = NULL;
 	struct bpf_link *link;
-
+	LIBBPF_OPTS(bpf_xdp_query_opts, query_opts);
 	struct xdp_md ctx_in = { .data = sizeof(__u32),
 				 .data_end = sizeof(data) };
 	DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
@@ -157,6 +159,29 @@ void test_xdp_do_redirect(void)
 	    !ASSERT_NEQ(ifindex_dst, 0, "ifindex_dst"))
 		goto out;
 
+	/* Check xdp features supported by veth driver */
+	err = bpf_xdp_query(ifindex_src, XDP_FLAGS_DRV_MODE, &query_opts);
+	if (!ASSERT_OK(err, "veth_src bpf_xdp_query"))
+		goto out;
+
+	if (!ASSERT_EQ(query_opts.feature_flags,
+		       NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
+		       NETDEV_XDP_ACT_NDO_XMIT | NETDEV_XDP_ACT_RX_SG |
+		       NETDEV_XDP_ACT_NDO_XMIT_SG,
+		       "veth_src query_opts.feature_flags"))
+		goto out;
+
+	err = bpf_xdp_query(ifindex_dst, XDP_FLAGS_DRV_MODE, &query_opts);
+	if (!ASSERT_OK(err, "veth_dst bpf_xdp_query"))
+		goto out;
+
+	if (!ASSERT_EQ(query_opts.feature_flags,
+		       NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
+		       NETDEV_XDP_ACT_NDO_XMIT | NETDEV_XDP_ACT_RX_SG |
+		       NETDEV_XDP_ACT_NDO_XMIT_SG,
+		       "veth_dst query_opts.feature_flags"))
+		goto out;
+
 	memcpy(skel->rodata->expect_dst, &pkt_udp.eth.h_dest, ETH_ALEN);
 	skel->rodata->ifindex_out = ifindex_src; /* redirect back to the same iface */
 	skel->rodata->ifindex_in = ifindex_src;

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

@@ -8,6 +8,7 @@ void serial_test_xdp_info(void)
 {
 	__u32 len = sizeof(struct bpf_prog_info), duration = 0, prog_id;
 	const char *file = "./xdp_dummy.bpf.o";
+	LIBBPF_OPTS(bpf_xdp_query_opts, opts);
 	struct bpf_prog_info info = {};
 	struct bpf_object *obj;
 	int err, prog_fd;
@@ -61,6 +62,13 @@ void serial_test_xdp_info(void)
 	if (CHECK(prog_id, "prog_id_drv", "unexpected prog_id=%u\n", prog_id))
 		goto out;
 
+	/* Check xdp features supported by lo device */
+	opts.feature_flags = ~0;
+	err = bpf_xdp_query(IFINDEX_LO, XDP_FLAGS_DRV_MODE, &opts);
+	if (!ASSERT_OK(err, "bpf_xdp_query"))
+		goto out;
+
+	ASSERT_EQ(opts.feature_flags, 0, "opts.feature_flags");
 out:
 	bpf_xdp_detach(IFINDEX_LO, 0, NULL);
 out_close: