1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Jesper Dangaard Brouer */
3
4 #include <linux/if_link.h> /* before test_progs.h, avoid bpf_util.h redefines */
5 #include <test_progs.h>
6 #include "test_check_mtu.skel.h"
7 #include "network_helpers.h"
8
9 #include <stdlib.h>
10 #include <inttypes.h>
11
12 #define IFINDEX_LO 1
13
14 static __u32 duration; /* Hint: needed for CHECK macro */
15
16 static int read_mtu_device_lo(void)
17 {
18 const char *filename = "/sys/class/net/lo/mtu";
19 char buf[11] = {};
20 int value, n, fd;
21
22 fd = open(filename, 0, O_RDONLY);
23 if (fd == -1)
24 return -1;
25
26 n = read(fd, buf, sizeof(buf));
27 close(fd);
28
29 if (n == -1)
30 return -2;
31
32 value = strtoimax(buf, NULL, 10);
33 if (errno == ERANGE)
34 return -3;
35
36 return value;
37 }
38
39 static void test_check_mtu_xdp_attach(void)
40 {
41 struct bpf_link_info link_info;
42 __u32 link_info_len = sizeof(link_info);
43 struct test_check_mtu *skel;
44 struct bpf_program *prog;
45 struct bpf_link *link;
46 int err = 0;
47 int fd;
48
49 skel = test_check_mtu__open_and_load();
50 if (CHECK(!skel, "open and load skel", "failed"))
51 return; /* Exit if e.g. helper unknown to kernel */
52
53 prog = skel->progs.xdp_use_helper_basic;
54
55 link = bpf_program__attach_xdp(prog, IFINDEX_LO);
56 if (!ASSERT_OK_PTR(link, "link_attach"))
57 goto out;
58 skel->links.xdp_use_helper_basic = link;
59
60 memset(&link_info, 0, sizeof(link_info));
61 fd = bpf_link__fd(link);
62 err = bpf_link_get_info_by_fd(fd, &link_info, &link_info_len);
63 if (CHECK(err, "link_info", "failed: %d\n", err))
64 goto out;
65
66 CHECK(link_info.type != BPF_LINK_TYPE_XDP, "link_type",
67 "got %u != exp %u\n", link_info.type, BPF_LINK_TYPE_XDP);
68 CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
69 "got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
70
71 err = bpf_link__detach(link);
72 CHECK(err, "link_detach", "failed %d\n", err);
73
74 out:
75 test_check_mtu__destroy(skel);
76 }
77
78 static void test_check_mtu_run_xdp(struct test_check_mtu *skel,
79 struct bpf_program *prog,
80 __u32 mtu_expect)
81 {
82 int retval_expect = XDP_PASS;
83 __u32 mtu_result = 0;
84 char buf[256] = {};
85 int err, prog_fd = bpf_program__fd(prog);
86 LIBBPF_OPTS(bpf_test_run_opts, topts,
87 .repeat = 1,
88 .data_in = &pkt_v4,
89 .data_size_in = sizeof(pkt_v4),
90 .data_out = buf,
91 .data_size_out = sizeof(buf),
92 );
93
94 err = bpf_prog_test_run_opts(prog_fd, &topts);
95 ASSERT_OK(err, "test_run");
96 ASSERT_EQ(topts.retval, retval_expect, "retval");
97
98 /* Extract MTU that BPF-prog got */
99 mtu_result = skel->bss->global_bpf_mtu_xdp;
100 ASSERT_EQ(mtu_result, mtu_expect, "MTU-compare-user");
101 }
102
103
104 static void test_check_mtu_xdp(__u32 mtu, __u32 ifindex)
105 {
106 struct test_check_mtu *skel;
107 int err;
108
109 skel = test_check_mtu__open();
110 if (CHECK(!skel, "skel_open", "failed"))
111 return;
112
113 /* Update "constants" in BPF-prog *BEFORE* libbpf load */
114 skel->rodata->GLOBAL_USER_MTU = mtu;
115 skel->rodata->GLOBAL_USER_IFINDEX = ifindex;
116
117 err = test_check_mtu__load(skel);
118 if (CHECK(err, "skel_load", "failed: %d\n", err))
119 goto cleanup;
120
121 test_check_mtu_run_xdp(skel, skel->progs.xdp_use_helper, mtu);
122 test_check_mtu_run_xdp(skel, skel->progs.xdp_exceed_mtu, mtu);
123 test_check_mtu_run_xdp(skel, skel->progs.xdp_minus_delta, mtu);
124 test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len, mtu);
125 test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len_exceed, mtu);
126
127 cleanup:
128 test_check_mtu__destroy(skel);
129 }
130
131 static void test_check_mtu_run_tc(struct test_check_mtu *skel,
132 struct bpf_program *prog,
133 __u32 mtu_expect)
134 {
135 int retval_expect = BPF_OK;
136 __u32 mtu_result = 0;
137 char buf[256] = {};
138 int err, prog_fd = bpf_program__fd(prog);
139 LIBBPF_OPTS(bpf_test_run_opts, topts,
140 .data_in = &pkt_v4,
141 .data_size_in = sizeof(pkt_v4),
142 .data_out = buf,
143 .data_size_out = sizeof(buf),
144 .repeat = 1,
145 );
146
147 err = bpf_prog_test_run_opts(prog_fd, &topts);
148 ASSERT_OK(err, "test_run");
149 ASSERT_EQ(topts.retval, retval_expect, "retval");
150
151 /* Extract MTU that BPF-prog got */
152 mtu_result = skel->bss->global_bpf_mtu_tc;
153 ASSERT_EQ(mtu_result, mtu_expect, "MTU-compare-user");
154 }
155
156
157 static void test_check_mtu_tc(__u32 mtu, __u32 ifindex)
158 {
159 struct test_check_mtu *skel;
160 int err;
161
162 skel = test_check_mtu__open();
163 if (CHECK(!skel, "skel_open", "failed"))
164 return;
165
166 /* Update "constants" in BPF-prog *BEFORE* libbpf load */
167 skel->rodata->GLOBAL_USER_MTU = mtu;
168 skel->rodata->GLOBAL_USER_IFINDEX = ifindex;
169
170 err = test_check_mtu__load(skel);
171 if (CHECK(err, "skel_load", "failed: %d\n", err))
172 goto cleanup;
173
174 test_check_mtu_run_tc(skel, skel->progs.tc_use_helper, mtu);
175 test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu, mtu);
176 test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu_da, mtu);
177 test_check_mtu_run_tc(skel, skel->progs.tc_minus_delta, mtu);
178 test_check_mtu_run_tc(skel, skel->progs.tc_input_len, mtu);
179 test_check_mtu_run_tc(skel, skel->progs.tc_input_len_exceed, mtu);
180 cleanup:
181 test_check_mtu__destroy(skel);
182 }
183
184 void serial_test_check_mtu(void)
185 {
186 int mtu_lo;
187
188 if (test__start_subtest("bpf_check_mtu XDP-attach"))
189 test_check_mtu_xdp_attach();
190
191 mtu_lo = read_mtu_device_lo();
192 if (CHECK(mtu_lo < 0, "reading MTU value", "failed (err:%d)", mtu_lo))
193 return;
194
195 if (test__start_subtest("bpf_check_mtu XDP-run"))
196 test_check_mtu_xdp(mtu_lo, 0);
197
198 if (test__start_subtest("bpf_check_mtu XDP-run ifindex-lookup"))
199 test_check_mtu_xdp(mtu_lo, IFINDEX_LO);
200
201 if (test__start_subtest("bpf_check_mtu TC-run"))
202 test_check_mtu_tc(mtu_lo, 0);
203
204 if (test__start_subtest("bpf_check_mtu TC-run ifindex-lookup"))
205 test_check_mtu_tc(mtu_lo, IFINDEX_LO);
206 }
207
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