1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2020 Facebook */
3#include <uapi/linux/if_link.h>
4#include <test_progs.h>
5#include "test_xdp_link.skel.h"
6
7#define IFINDEX_LO 1
8
9void serial_test_xdp_link(void)
10{
11	struct test_xdp_link *skel1 = NULL, *skel2 = NULL;
12	__u32 id1, id2, id0 = 0, prog_fd1, prog_fd2;
13	LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
14	struct bpf_link_info link_info;
15	struct bpf_prog_info prog_info;
16	struct bpf_link *link;
17	int err;
18	__u32 link_info_len = sizeof(link_info);
19	__u32 prog_info_len = sizeof(prog_info);
20
21	skel1 = test_xdp_link__open_and_load();
22	if (!ASSERT_OK_PTR(skel1, "skel_load"))
23		goto cleanup;
24	prog_fd1 = bpf_program__fd(skel1->progs.xdp_handler);
25
26	skel2 = test_xdp_link__open_and_load();
27	if (!ASSERT_OK_PTR(skel2, "skel_load"))
28		goto cleanup;
29	prog_fd2 = bpf_program__fd(skel2->progs.xdp_handler);
30
31	memset(&prog_info, 0, sizeof(prog_info));
32	err = bpf_prog_get_info_by_fd(prog_fd1, &prog_info, &prog_info_len);
33	if (!ASSERT_OK(err, "fd_info1"))
34		goto cleanup;
35	id1 = prog_info.id;
36
37	memset(&prog_info, 0, sizeof(prog_info));
38	err = bpf_prog_get_info_by_fd(prog_fd2, &prog_info, &prog_info_len);
39	if (!ASSERT_OK(err, "fd_info2"))
40		goto cleanup;
41	id2 = prog_info.id;
42
43	/* set initial prog attachment */
44	err = bpf_xdp_attach(IFINDEX_LO, prog_fd1, XDP_FLAGS_REPLACE, &opts);
45	if (!ASSERT_OK(err, "fd_attach"))
46		goto cleanup;
47
48	/* validate prog ID */
49	err = bpf_xdp_query_id(IFINDEX_LO, 0, &id0);
50	if (!ASSERT_OK(err, "id1_check_err") || !ASSERT_EQ(id0, id1, "id1_check_val"))
51		goto cleanup;
52
53	/* BPF link is not allowed to replace prog attachment */
54	link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
55	if (!ASSERT_ERR_PTR(link, "link_attach_should_fail")) {
56		bpf_link__destroy(link);
57		/* best-effort detach prog */
58		opts.old_prog_fd = prog_fd1;
59		bpf_xdp_detach(IFINDEX_LO, XDP_FLAGS_REPLACE, &opts);
60		goto cleanup;
61	}
62
63	/* detach BPF program */
64	opts.old_prog_fd = prog_fd1;
65	err = bpf_xdp_detach(IFINDEX_LO, XDP_FLAGS_REPLACE, &opts);
66	if (!ASSERT_OK(err, "prog_detach"))
67		goto cleanup;
68
69	/* now BPF link should attach successfully */
70	link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
71	if (!ASSERT_OK_PTR(link, "link_attach"))
72		goto cleanup;
73	skel1->links.xdp_handler = link;
74
75	/* validate prog ID */
76	err = bpf_xdp_query_id(IFINDEX_LO, 0, &id0);
77	if (!ASSERT_OK(err, "id1_check_err") || !ASSERT_EQ(id0, id1, "id1_check_val"))
78		goto cleanup;
79
80	/* BPF prog attach is not allowed to replace BPF link */
81	opts.old_prog_fd = prog_fd1;
82	err = bpf_xdp_attach(IFINDEX_LO, prog_fd2, XDP_FLAGS_REPLACE, &opts);
83	if (!ASSERT_ERR(err, "prog_attach_fail"))
84		goto cleanup;
85
86	/* Can't force-update when BPF link is active */
87	err = bpf_xdp_attach(IFINDEX_LO, prog_fd2, 0, NULL);
88	if (!ASSERT_ERR(err, "prog_update_fail"))
89		goto cleanup;
90
91	/* Can't force-detach when BPF link is active */
92	err = bpf_xdp_detach(IFINDEX_LO, 0, NULL);
93	if (!ASSERT_ERR(err, "prog_detach_fail"))
94		goto cleanup;
95
96	/* BPF link is not allowed to replace another BPF link */
97	link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
98	if (!ASSERT_ERR_PTR(link, "link_attach_should_fail")) {
99		bpf_link__destroy(link);
100		goto cleanup;
101	}
102
103	bpf_link__destroy(skel1->links.xdp_handler);
104	skel1->links.xdp_handler = NULL;
105
106	/* new link attach should succeed */
107	link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
108	if (!ASSERT_OK_PTR(link, "link_attach"))
109		goto cleanup;
110	skel2->links.xdp_handler = link;
111
112	err = bpf_xdp_query_id(IFINDEX_LO, 0, &id0);
113	if (!ASSERT_OK(err, "id2_check_err") || !ASSERT_EQ(id0, id2, "id2_check_val"))
114		goto cleanup;
115
116	/* updating program under active BPF link works as expected */
117	err = bpf_link__update_program(link, skel1->progs.xdp_handler);
118	if (!ASSERT_OK(err, "link_upd"))
119		goto cleanup;
120
121	memset(&link_info, 0, sizeof(link_info));
122	err = bpf_link_get_info_by_fd(bpf_link__fd(link),
123				      &link_info, &link_info_len);
124	if (!ASSERT_OK(err, "link_info"))
125		goto cleanup;
126
127	ASSERT_EQ(link_info.type, BPF_LINK_TYPE_XDP, "link_type");
128	ASSERT_EQ(link_info.prog_id, id1, "link_prog_id");
129	ASSERT_EQ(link_info.xdp.ifindex, IFINDEX_LO, "link_ifindex");
130
131	/* updating program under active BPF link with different type fails */
132	err = bpf_link__update_program(link, skel1->progs.tc_handler);
133	if (!ASSERT_ERR(err, "link_upd_invalid"))
134		goto cleanup;
135
136	err = bpf_link__detach(link);
137	if (!ASSERT_OK(err, "link_detach"))
138		goto cleanup;
139
140	memset(&link_info, 0, sizeof(link_info));
141	err = bpf_link_get_info_by_fd(bpf_link__fd(link),
142				      &link_info, &link_info_len);
143
144	ASSERT_OK(err, "link_info");
145	ASSERT_EQ(link_info.prog_id, id1, "link_prog_id");
146	/* ifindex should be zeroed out */
147	ASSERT_EQ(link_info.xdp.ifindex, 0, "link_ifindex");
148
149cleanup:
150	test_xdp_link__destroy(skel1);
151	test_xdp_link__destroy(skel2);
152}
153