bpf/prog_tests/check_mtu.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2020 Jesper Dangaard Brouer */
0003
0004 #include <linux/if_link.h> /* before test_progs.h, avoid bpf_util.h redefines */
0005 #include <test_progs.h>
0006 #include "test_check_mtu.skel.h"
0007 #include "network_helpers.h"
0008
0009 #include <stdlib.h>
0010 #include <inttypes.h>
0011
0012 #define IFINDEX_LO 1
0013
0014 static __u32 duration; /* Hint: needed for CHECK macro */
0015
0016 static int read_mtu_device_lo(void)
0017 {
0018     const char *filename = "/sys/class/net/lo/mtu";
0019     char buf[11] = {};
0020     int value, n, fd;
0021
0022     fd = open(filename, 0, O_RDONLY);
0023     if (fd == -1)
0024         return -1;
0025
0026     n = read(fd, buf, sizeof(buf));
0027     close(fd);
0028
0029     if (n == -1)
0030         return -2;
0031
0032     value = strtoimax(buf, NULL, 10);
0033     if (errno == ERANGE)
0034         return -3;
0035
0036     return value;
0037 }
0038
0039 static void test_check_mtu_xdp_attach(void)
0040 {
0041     struct bpf_link_info link_info;
0042     __u32 link_info_len = sizeof(link_info);
0043     struct test_check_mtu *skel;
0044     struct bpf_program *prog;
0045     struct bpf_link *link;
0046     int err = 0;
0047     int fd;
0048
0049     skel = test_check_mtu__open_and_load();
0050     if (CHECK(!skel, "open and load skel", "failed"))
0051         return; /* Exit if e.g. helper unknown to kernel */
0052
0053     prog = skel->progs.xdp_use_helper_basic;
0054
0055     link = bpf_program__attach_xdp(prog, IFINDEX_LO);
0056     if (!ASSERT_OK_PTR(link, "link_attach"))
0057         goto out;
0058     skel->links.xdp_use_helper_basic = link;
0059
0060     memset(&link_info, 0, sizeof(link_info));
0061     fd = bpf_link__fd(link);
0062     err = bpf_obj_get_info_by_fd(fd, &link_info, &link_info_len);
0063     if (CHECK(err, "link_info", "failed: %d\n", err))
0064         goto out;
0065
0066     CHECK(link_info.type != BPF_LINK_TYPE_XDP, "link_type",
0067           "got %u != exp %u\n", link_info.type, BPF_LINK_TYPE_XDP);
0068     CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
0069           "got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
0070
0071     err = bpf_link__detach(link);
0072     CHECK(err, "link_detach", "failed %d\n", err);
0073
0074 out:
0075     test_check_mtu__destroy(skel);
0076 }
0077
0078 static void test_check_mtu_run_xdp(struct test_check_mtu *skel,
0079                    struct bpf_program *prog,
0080                    __u32 mtu_expect)
0081 {
0082     int retval_expect = XDP_PASS;
0083     __u32 mtu_result = 0;
0084     char buf[256] = {};
0085     int err, prog_fd = bpf_program__fd(prog);
0086     LIBBPF_OPTS(bpf_test_run_opts, topts,
0087         .repeat = 1,
0088         .data_in = &pkt_v4,
0089         .data_size_in = sizeof(pkt_v4),
0090         .data_out = buf,
0091         .data_size_out = sizeof(buf),
0092     );
0093
0094     err = bpf_prog_test_run_opts(prog_fd, &topts);
0095     ASSERT_OK(err, "test_run");
0096     ASSERT_EQ(topts.retval, retval_expect, "retval");
0097
0098     /* Extract MTU that BPF-prog got */
0099     mtu_result = skel->bss->global_bpf_mtu_xdp;
0100     ASSERT_EQ(mtu_result, mtu_expect, "MTU-compare-user");
0101 }
0102
0103
0104 static void test_check_mtu_xdp(__u32 mtu, __u32 ifindex)
0105 {
0106     struct test_check_mtu *skel;
0107     int err;
0108
0109     skel = test_check_mtu__open();
0110     if (CHECK(!skel, "skel_open", "failed"))
0111         return;
0112
0113     /* Update "constants" in BPF-prog *BEFORE* libbpf load */
0114     skel->rodata->GLOBAL_USER_MTU = mtu;
0115     skel->rodata->GLOBAL_USER_IFINDEX = ifindex;
0116
0117     err = test_check_mtu__load(skel);
0118     if (CHECK(err, "skel_load", "failed: %d\n", err))
0119         goto cleanup;
0120
0121     test_check_mtu_run_xdp(skel, skel->progs.xdp_use_helper, mtu);
0122     test_check_mtu_run_xdp(skel, skel->progs.xdp_exceed_mtu, mtu);
0123     test_check_mtu_run_xdp(skel, skel->progs.xdp_minus_delta, mtu);
0124     test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len, mtu);
0125     test_check_mtu_run_xdp(skel, skel->progs.xdp_input_len_exceed, mtu);
0126
0127 cleanup:
0128     test_check_mtu__destroy(skel);
0129 }
0130
0131 static void test_check_mtu_run_tc(struct test_check_mtu *skel,
0132                   struct bpf_program *prog,
0133                   __u32 mtu_expect)
0134 {
0135     int retval_expect = BPF_OK;
0136     __u32 mtu_result = 0;
0137     char buf[256] = {};
0138     int err, prog_fd = bpf_program__fd(prog);
0139     LIBBPF_OPTS(bpf_test_run_opts, topts,
0140         .data_in = &pkt_v4,
0141         .data_size_in = sizeof(pkt_v4),
0142         .data_out = buf,
0143         .data_size_out = sizeof(buf),
0144         .repeat = 1,
0145     );
0146
0147     err = bpf_prog_test_run_opts(prog_fd, &topts);
0148     ASSERT_OK(err, "test_run");
0149     ASSERT_EQ(topts.retval, retval_expect, "retval");
0150
0151     /* Extract MTU that BPF-prog got */
0152     mtu_result = skel->bss->global_bpf_mtu_tc;
0153     ASSERT_EQ(mtu_result, mtu_expect, "MTU-compare-user");
0154 }
0155
0156
0157 static void test_check_mtu_tc(__u32 mtu, __u32 ifindex)
0158 {
0159     struct test_check_mtu *skel;
0160     int err;
0161
0162     skel = test_check_mtu__open();
0163     if (CHECK(!skel, "skel_open", "failed"))
0164         return;
0165
0166     /* Update "constants" in BPF-prog *BEFORE* libbpf load */
0167     skel->rodata->GLOBAL_USER_MTU = mtu;
0168     skel->rodata->GLOBAL_USER_IFINDEX = ifindex;
0169
0170     err = test_check_mtu__load(skel);
0171     if (CHECK(err, "skel_load", "failed: %d\n", err))
0172         goto cleanup;
0173
0174     test_check_mtu_run_tc(skel, skel->progs.tc_use_helper, mtu);
0175     test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu, mtu);
0176     test_check_mtu_run_tc(skel, skel->progs.tc_exceed_mtu_da, mtu);
0177     test_check_mtu_run_tc(skel, skel->progs.tc_minus_delta, mtu);
0178     test_check_mtu_run_tc(skel, skel->progs.tc_input_len, mtu);
0179     test_check_mtu_run_tc(skel, skel->progs.tc_input_len_exceed, mtu);
0180 cleanup:
0181     test_check_mtu__destroy(skel);
0182 }
0183
0184 void serial_test_check_mtu(void)
0185 {
0186     __u32 mtu_lo;
0187
0188     if (test__start_subtest("bpf_check_mtu XDP-attach"))
0189         test_check_mtu_xdp_attach();
0190
0191     mtu_lo = read_mtu_device_lo();
0192     if (CHECK(mtu_lo < 0, "reading MTU value", "failed (err:%d)", mtu_lo))
0193         return;
0194
0195     if (test__start_subtest("bpf_check_mtu XDP-run"))
0196         test_check_mtu_xdp(mtu_lo, 0);
0197
0198     if (test__start_subtest("bpf_check_mtu XDP-run ifindex-lookup"))
0199         test_check_mtu_xdp(mtu_lo, IFINDEX_LO);
0200
0201     if (test__start_subtest("bpf_check_mtu TC-run"))
0202         test_check_mtu_tc(mtu_lo, 0);
0203
0204     if (test__start_subtest("bpf_check_mtu TC-run ifindex-lookup"))
0205         test_check_mtu_tc(mtu_lo, IFINDEX_LO);
0206 }