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
test_xdp_link(void)9 void test_xdp_link(void)
10 {
11 __u32 duration = 0, id1, id2, id0 = 0, prog_fd1, prog_fd2, err;
12 DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts, .old_fd = -1);
13 struct test_xdp_link *skel1 = NULL, *skel2 = NULL;
14 struct bpf_link_info link_info;
15 struct bpf_prog_info prog_info;
16 struct bpf_link *link;
17 __u32 link_info_len = sizeof(link_info);
18 __u32 prog_info_len = sizeof(prog_info);
19
20 skel1 = test_xdp_link__open_and_load();
21 if (CHECK(!skel1, "skel_load", "skeleton open and load failed\n"))
22 goto cleanup;
23 prog_fd1 = bpf_program__fd(skel1->progs.xdp_handler);
24
25 skel2 = test_xdp_link__open_and_load();
26 if (CHECK(!skel2, "skel_load", "skeleton open and load failed\n"))
27 goto cleanup;
28 prog_fd2 = bpf_program__fd(skel2->progs.xdp_handler);
29
30 memset(&prog_info, 0, sizeof(prog_info));
31 err = bpf_obj_get_info_by_fd(prog_fd1, &prog_info, &prog_info_len);
32 if (CHECK(err, "fd_info1", "failed %d\n", -errno))
33 goto cleanup;
34 id1 = prog_info.id;
35
36 memset(&prog_info, 0, sizeof(prog_info));
37 err = bpf_obj_get_info_by_fd(prog_fd2, &prog_info, &prog_info_len);
38 if (CHECK(err, "fd_info2", "failed %d\n", -errno))
39 goto cleanup;
40 id2 = prog_info.id;
41
42 /* set initial prog attachment */
43 err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd1, XDP_FLAGS_REPLACE, &opts);
44 if (CHECK(err, "fd_attach", "initial prog attach failed: %d\n", err))
45 goto cleanup;
46
47 /* validate prog ID */
48 err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
49 CHECK(err || id0 != id1, "id1_check",
50 "loaded prog id %u != id1 %u, err %d", id0, id1, err);
51
52 /* BPF link is not allowed to replace prog attachment */
53 link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
54 if (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
55 bpf_link__destroy(link);
56 /* best-effort detach prog */
57 opts.old_fd = prog_fd1;
58 bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
59 goto cleanup;
60 }
61
62 /* detach BPF program */
63 opts.old_fd = prog_fd1;
64 err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
65 if (CHECK(err, "prog_detach", "failed %d\n", err))
66 goto cleanup;
67
68 /* now BPF link should attach successfully */
69 link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
70 if (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
71 goto cleanup;
72 skel1->links.xdp_handler = link;
73
74 /* validate prog ID */
75 err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
76 if (CHECK(err || id0 != id1, "id1_check",
77 "loaded prog id %u != id1 %u, err %d", id0, id1, err))
78 goto cleanup;
79
80 /* BPF prog attach is not allowed to replace BPF link */
81 opts.old_fd = prog_fd1;
82 err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd2, XDP_FLAGS_REPLACE, &opts);
83 if (CHECK(!err, "prog_attach_fail", "unexpected success\n"))
84 goto cleanup;
85
86 /* Can't force-update when BPF link is active */
87 err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd2, 0);
88 if (CHECK(!err, "prog_update_fail", "unexpected success\n"))
89 goto cleanup;
90
91 /* Can't force-detach when BPF link is active */
92 err = bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
93 if (CHECK(!err, "prog_detach_fail", "unexpected success\n"))
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 (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
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 (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
109 goto cleanup;
110 skel2->links.xdp_handler = link;
111
112 err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
113 if (CHECK(err || id0 != id2, "id2_check",
114 "loaded prog id %u != id2 %u, err %d", id0, id1, err))
115 goto cleanup;
116
117 /* updating program under active BPF link works as expected */
118 err = bpf_link__update_program(link, skel1->progs.xdp_handler);
119 if (CHECK(err, "link_upd", "failed: %d\n", err))
120 goto cleanup;
121
122 memset(&link_info, 0, sizeof(link_info));
123 err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
124 if (CHECK(err, "link_info", "failed: %d\n", err))
125 goto cleanup;
126
127 CHECK(link_info.type != BPF_LINK_TYPE_XDP, "link_type",
128 "got %u != exp %u\n", link_info.type, BPF_LINK_TYPE_XDP);
129 CHECK(link_info.prog_id != id1, "link_prog_id",
130 "got %u != exp %u\n", link_info.prog_id, id1);
131 CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
132 "got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
133
134 err = bpf_link__detach(link);
135 if (CHECK(err, "link_detach", "failed %d\n", err))
136 goto cleanup;
137
138 memset(&link_info, 0, sizeof(link_info));
139 err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
140 if (CHECK(err, "link_info", "failed: %d\n", err))
141 goto cleanup;
142 CHECK(link_info.prog_id != id1, "link_prog_id",
143 "got %u != exp %u\n", link_info.prog_id, id1);
144 /* ifindex should be zeroed out */
145 CHECK(link_info.xdp.ifindex != 0, "link_ifindex",
146 "got %u != exp %u\n", link_info.xdp.ifindex, 0);
147
148 cleanup:
149 test_xdp_link__destroy(skel1);
150 test_xdp_link__destroy(skel2);
151 }
152