Add selftest validating all the attachment logic around BPF XDP link. Test
also link updates and get_obj_info() APIs.
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
.../selftests/bpf/prog_tests/xdp_link.c | 137 ++++++++++++++++++
.../selftests/bpf/progs/test_xdp_link.c | 12 ++
2 files changed, 149 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_link.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_link.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_link.c b/tools/testing/selftests/bpf/prog_tests/xdp_link.c
new file mode 100644
index 000000000000..52cba6795d40
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_link.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <uapi/linux/if_link.h>
+#include <test_progs.h>
+#include "test_xdp_link.skel.h"
+
+#define IFINDEX_LO 1
+
+void test_xdp_link(void)
+{
+ __u32 duration = 0, id1, id2, id0 = 0, prog_fd1, prog_fd2, err;
+ DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts, .old_fd = -1);
+ struct test_xdp_link *skel1 = NULL, *skel2 = NULL;
+ struct bpf_link_info link_info;
+ struct bpf_prog_info prog_info;
+ struct bpf_link *link;
+ __u32 link_info_len = sizeof(link_info);
+ __u32 prog_info_len = sizeof(prog_info);
+
+ skel1 = test_xdp_link__open_and_load();
+ if (CHECK(!skel1, "skel_load", "skeleton open and load failed\n"))
+ goto cleanup;
+ prog_fd1 = bpf_program__fd(skel1->progs.xdp_handler);
+
+ skel2 = test_xdp_link__open_and_load();
+ if (CHECK(!skel2, "skel_load", "skeleton open and load failed\n"))
+ goto cleanup;
+ prog_fd2 = bpf_program__fd(skel2->progs.xdp_handler);
+
+ memset(&prog_info, 0, sizeof(prog_info));
+ err = bpf_obj_get_info_by_fd(prog_fd1, &prog_info, &prog_info_len);
+ if (CHECK(err, "fd_info1", "failed %d\n", -errno))
+ goto cleanup;
+ id1 = prog_info.id;
+
+ memset(&prog_info, 0, sizeof(prog_info));
+ err = bpf_obj_get_info_by_fd(prog_fd2, &prog_info, &prog_info_len);
+ if (CHECK(err, "fd_info2", "failed %d\n", -errno))
+ goto cleanup;
+ id2 = prog_info.id;
+
+ /* set initial prog attachment */
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd1, XDP_FLAGS_REPLACE, &opts);
+ if (CHECK(err, "fd_attach", "initial prog attach failed: %d\n", err))
+ goto cleanup;
+
+ /* validate prog ID */
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
+ CHECK(err || id0 != id1, "id1_check",
+ "loaded prog id %u != id1 %u, err %d", id0, id1, err);
+
+ /* BPF link is not allowed to replace prog attachment */
+ link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
+ if (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
+ bpf_link__destroy(link);
+ /* best-effort detach prog */
+ opts.old_fd = prog_fd1;
+ bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
+ goto cleanup;
+ }
+
+ /* detach BPF program */
+ opts.old_fd = prog_fd1;
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
+ if (CHECK(err, "prog_detach", "failed %d\n", err))
+ goto cleanup;
+
+ /* now BPF link should attach successfully */
+ link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
+ if (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
+ goto cleanup;
+ skel1->links.xdp_handler = link;
+
+ /* validate prog ID */
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
+ if (CHECK(err || id0 != id1, "id1_check",
+ "loaded prog id %u != id1 %u, err %d", id0, id1, err))
+ goto cleanup;
+
+ /* BPF prog attach is not allowed to replace BPF link */
+ opts.old_fd = prog_fd1;
+ err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd2, XDP_FLAGS_REPLACE, &opts);
+ if (CHECK(!err, "prog_attach_fail", "unexpected success\n"))
+ goto cleanup;
+
+ /* Can't force-update when BPF link is active */
+ err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd2, 0);
+ if (CHECK(!err, "prog_update_fail", "unexpected success\n"))
+ goto cleanup;
+
+ /* Can't force-detach when BPF link is active */
+ err = bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
+ if (CHECK(!err, "prog_detach_fail", "unexpected success\n"))
+ goto cleanup;
+
+ /* BPF link is not allowed to replace another BPF link */
+ link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
+ if (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
+ bpf_link__destroy(link);
+ goto cleanup;
+ }
+
+ bpf_link__destroy(skel1->links.xdp_handler);
+ skel1->links.xdp_handler = NULL;
+
+ /* new link attach should succeed */
+ link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
+ if (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
+ goto cleanup;
+ skel2->links.xdp_handler = link;
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
+ if (CHECK(err || id0 != id2, "id2_check",
+ "loaded prog id %u != id2 %u, err %d", id0, id1, err))
+ goto cleanup;
+
+ /* updating program under active BPF link works as expected */
+ err = bpf_link__update_program(link, skel1->progs.xdp_handler);
+ if (CHECK(err, "link_upd", "failed: %d\n", err))
+ goto cleanup;
+
+ memset(&link_info, 0, sizeof(link_info));
+ err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
+ if (CHECK(err, "link_info", "failed: %d\n", err))
+ goto cleanup;
+
+ CHECK(link_info.type != BPF_LINK_TYPE_XDP, "link_type",
+ "got %u != exp %u\n", link_info.type, BPF_LINK_TYPE_XDP);
+ CHECK(link_info.prog_id != id1, "link_prog_id",
+ "got %u != exp %u\n", link_info.prog_id, id1);
+ CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
+ "got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
+
+cleanup:
+ test_xdp_link__destroy(skel1);
+ test_xdp_link__destroy(skel2);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_link.c b/tools/testing/selftests/bpf/progs/test_xdp_link.c
new file mode 100644
index 000000000000..eb93ea95d1d8
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_link.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char LICENSE[] SEC("license") = "GPL";
+
+SEC("xdp/handler")
+int xdp_handler(struct xdp_md *xdp)
+{
+ return 0;
+}
--
2.24.1
