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 static void test_chk_segs_flag(struct test_check_mtu *skel, __u32 mtu) 157 { 158 int err, prog_fd = bpf_program__fd(skel->progs.tc_chk_segs_flag); 159 struct __sk_buff skb = { 160 .gso_size = 10, 161 }; 162 LIBBPF_OPTS(bpf_test_run_opts, topts, 163 .data_in = &pkt_v4, 164 .data_size_in = sizeof(pkt_v4), 165 .ctx_in = &skb, 166 .ctx_size_in = sizeof(skb), 167 ); 168 169 /* Lower the mtu to test the BPF_MTU_CHK_SEGS */ 170 SYS_NOFAIL("ip link set dev lo mtu 10"); 171 err = bpf_prog_test_run_opts(prog_fd, &topts); 172 SYS_NOFAIL("ip link set dev lo mtu %u", mtu); 173 ASSERT_OK(err, "test_run"); 174 ASSERT_EQ(topts.retval, BPF_OK, "retval"); 175 } 176 177 static void test_check_mtu_tc(__u32 mtu, __u32 ifindex) 178 { 179 struct test_check_mtu *skel; 180 int err; 181 182 skel = test_check_mtu__open(); 183 if (CHECK(!skel, "skel_open", "failed")) 184 return; 185 186 /* Update "constants" in BPF-prog *BEFORE* libbpf load */ 187 skel->rodata->GLOBAL_USER_MTU = mtu; 188 skel->rodata->GLOBAL_USER_IFINDEX = ifindex; 189 190 err = test_check_mtu__load(skel); 191 if (CHECK(err, "skel_load", "failed: %d\n", err)) 192 goto cleanup; 193 194 test_check_mtu_run_tc(skel, skel->progs.tc_use_helper, mtu); 195 test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu, mtu); 196 test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu_da, mtu); 197 test_check_mtu_run_tc(skel, skel->progs.tc_minus_delta, mtu); 198 test_check_mtu_run_tc(skel, skel->progs.tc_input_len, mtu); 199 test_check_mtu_run_tc(skel, skel->progs.tc_input_len_exceed, mtu); 200 test_chk_segs_flag(skel, mtu); 201 cleanup: 202 test_check_mtu__destroy(skel); 203 } 204 205 void test_ns_check_mtu(void) 206 { 207 int mtu_lo; 208 209 if (test__start_subtest("bpf_check_mtu XDP-attach")) 210 test_check_mtu_xdp_attach(); 211 212 mtu_lo = read_mtu_device_lo(); 213 if (CHECK(mtu_lo < 0, "reading MTU value", "failed (err:%d)", mtu_lo)) 214 return; 215 216 if (test__start_subtest("bpf_check_mtu XDP-run")) 217 test_check_mtu_xdp(mtu_lo, 0); 218 219 if (test__start_subtest("bpf_check_mtu XDP-run ifindex-lookup")) 220 test_check_mtu_xdp(mtu_lo, IFINDEX_LO); 221 222 if (test__start_subtest("bpf_check_mtu TC-run")) 223 test_check_mtu_tc(mtu_lo, 0); 224 225 if (test__start_subtest("bpf_check_mtu TC-run ifindex-lookup")) 226 test_check_mtu_tc(mtu_lo, IFINDEX_LO); 227 } 228