tools/testing/selftests/bpf/prog_tests/cgroup_link.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <test_progs.h>
   4 #include "cgroup_helpers.h"
   5 #include "testing_helpers.h"
   6 #include "test_cgroup_link.skel.h"
   7
   8 static __u32 duration = 0;
   9 #define PING_CMD        "ping -q -c1 -w1 127.0.0.1 > /dev/null"
  10
  11 static struct test_cgroup_link *skel = NULL;
  12
  13 int ping_and_check(int exp_calls, int exp_alt_calls)
  14 {
  15         skel->bss->calls = 0;
  16         skel->bss->alt_calls = 0;
  17         CHECK_FAIL(system(PING_CMD));
  18         if (CHECK(skel->bss->calls != exp_calls, "call_cnt",
  19                   "exp %d, got %d\n", exp_calls, skel->bss->calls))
  20                 return -EINVAL;
  21         if (CHECK(skel->bss->alt_calls != exp_alt_calls, "alt_call_cnt",
  22                   "exp %d, got %d\n", exp_alt_calls, skel->bss->alt_calls))
  23                 return -EINVAL;
  24         return 0;
  25 }
  26
  27 void test_cgroup_link(void)
  28 {
  29         struct {
  30                 const char *path;
  31                 int fd;
  32         } cgs[] = {
  33                 { "/cg1" },
  34                 { "/cg1/cg2" },
  35                 { "/cg1/cg2/cg3" },
  36                 { "/cg1/cg2/cg3/cg4" },
  37         };
  38         int last_cg = ARRAY_SIZE(cgs) - 1, cg_nr = ARRAY_SIZE(cgs);
  39         DECLARE_LIBBPF_OPTS(bpf_link_update_opts, link_upd_opts);
  40         struct bpf_link *links[ARRAY_SIZE(cgs)] = {}, *tmp_link;
  41         __u32 prog_ids[ARRAY_SIZE(cgs)], prog_cnt = 0, attach_flags, prog_id;
  42         struct bpf_link_info info;
  43         int i = 0, err, prog_fd;
  44         bool detach_legacy = false;
  45
  46         skel = test_cgroup_link__open_and_load();
  47         if (CHECK(!skel, "skel_open_load", "failed to open/load skeleton\n"))
  48                 return;
  49         prog_fd = bpf_program__fd(skel->progs.egress);
  50
  51         err = setup_cgroup_environment();
  52         if (CHECK(err, "cg_init", "failed: %d\n", err))
  53                 goto cleanup;
  54
  55         for (i = 0; i < cg_nr; i++) {
  56                 cgs[i].fd = create_and_get_cgroup(cgs[i].path);
  57                 if (CHECK(cgs[i].fd < 0, "cg_create", "fail: %d\n", cgs[i].fd))
  58                         goto cleanup;
  59         }
  60
  61         err = join_cgroup(cgs[last_cg].path);
  62         if (CHECK(err, "cg_join", "fail: %d\n", err))
  63                 goto cleanup;
  64
  65         for (i = 0; i < cg_nr; i++) {
  66                 links[i] = bpf_program__attach_cgroup(skel->progs.egress,
  67                                                       cgs[i].fd);
  68                 if (CHECK(IS_ERR(links[i]), "cg_attach", "i: %d, err: %ld\n",
  69                                  i, PTR_ERR(links[i])))
  70                         goto cleanup;
  71         }
  72
  73         ping_and_check(cg_nr, 0);
  74
  75         /* query the number of effective progs and attach flags in root cg */
  76         err = bpf_prog_query(cgs[0].fd, BPF_CGROUP_INET_EGRESS,
  77                              BPF_F_QUERY_EFFECTIVE, &attach_flags, NULL,
  78                              &prog_cnt);
  79         CHECK_FAIL(err);
  80         CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
  81         if (CHECK(prog_cnt != 1, "effect_cnt", "exp %d, got %d\n", 1, prog_cnt))
  82                 goto cleanup;
  83
  84         /* query the number of effective progs in last cg */
  85         err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
  86                              BPF_F_QUERY_EFFECTIVE, NULL, NULL,
  87                              &prog_cnt);
  88         CHECK_FAIL(err);
  89         CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
  90         if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
  91                   cg_nr, prog_cnt))
  92                 goto cleanup;
  93
  94         /* query the effective prog IDs in last cg */
  95         err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
  96                              BPF_F_QUERY_EFFECTIVE, &attach_flags,
  97                              prog_ids, &prog_cnt);
  98         CHECK_FAIL(err);
  99         CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
 100         if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
 101                   cg_nr, prog_cnt))
 102                 goto cleanup;
 103         for (i = 1; i < prog_cnt; i++) {
 104                 CHECK(prog_ids[i - 1] != prog_ids[i], "prog_id_check",
 105                       "idx %d, prev id %d, cur id %d\n",
 106                       i, prog_ids[i - 1], prog_ids[i]);
 107         }
 108
 109         /* detach bottom program and ping again */
 110         bpf_link__destroy(links[last_cg]);
 111         links[last_cg] = NULL;
 112
 113         ping_and_check(cg_nr - 1, 0);
 114
 115         /* mix in with non link-based multi-attachments */
 116         err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
 117                               BPF_CGROUP_INET_EGRESS, BPF_F_ALLOW_MULTI);
 118         if (CHECK(err, "cg_attach_legacy", "errno=%d\n", errno))
 119                 goto cleanup;
 120         detach_legacy = true;
 121
 122         links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
 123                                                     cgs[last_cg].fd);
 124         if (CHECK(IS_ERR(links[last_cg]), "cg_attach", "err: %ld\n",
 125                   PTR_ERR(links[last_cg])))
 126                 goto cleanup;
 127
 128         ping_and_check(cg_nr + 1, 0);
 129
 130         /* detach link */
 131         bpf_link__destroy(links[last_cg]);
 132         links[last_cg] = NULL;
 133
 134         /* detach legacy */
 135         err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
 136         if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
 137                 goto cleanup;
 138         detach_legacy = false;
 139
 140         /* attach legacy exclusive prog attachment */
 141         err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
 142                               BPF_CGROUP_INET_EGRESS, 0);
 143         if (CHECK(err, "cg_attach_exclusive", "errno=%d\n", errno))
 144                 goto cleanup;
 145         detach_legacy = true;
 146
 147         /* attempt to mix in with multi-attach bpf_link */
 148         tmp_link = bpf_program__attach_cgroup(skel->progs.egress,
 149                                               cgs[last_cg].fd);
 150         if (CHECK(!IS_ERR(tmp_link), "cg_attach_fail", "unexpected success!\n")) {
 151                 bpf_link__destroy(tmp_link);
 152                 goto cleanup;
 153         }
 154
 155         ping_and_check(cg_nr, 0);
 156
 157         /* detach */
 158         err = bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
 159         if (CHECK(err, "cg_detach_legacy", "errno=%d\n", errno))
 160                 goto cleanup;
 161         detach_legacy = false;
 162
 163         ping_and_check(cg_nr - 1, 0);
 164
 165         /* attach back link-based one */
 166         links[last_cg] = bpf_program__attach_cgroup(skel->progs.egress,
 167                                                     cgs[last_cg].fd);
 168         if (CHECK(IS_ERR(links[last_cg]), "cg_attach", "err: %ld\n",
 169                   PTR_ERR(links[last_cg])))
 170                 goto cleanup;
 171
 172         ping_and_check(cg_nr, 0);
 173
 174         /* check legacy exclusive prog can't be attached */
 175         err = bpf_prog_attach(prog_fd, cgs[last_cg].fd,
 176                               BPF_CGROUP_INET_EGRESS, 0);
 177         if (CHECK(!err, "cg_attach_exclusive", "unexpected success")) {
 178                 bpf_prog_detach2(prog_fd, cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS);
 179                 goto cleanup;
 180         }
 181
 182         /* replace BPF programs inside their links for all but first link */
 183         for (i = 1; i < cg_nr; i++) {
 184                 err = bpf_link__update_program(links[i], skel->progs.egress_alt);
 185                 if (CHECK(err, "prog_upd", "link #%d\n", i))
 186                         goto cleanup;
 187         }
 188
 189         ping_and_check(1, cg_nr - 1);
 190
 191         /* Attempt program update with wrong expected BPF program */
 192         link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress_alt);
 193         link_upd_opts.flags = BPF_F_REPLACE;
 194         err = bpf_link_update(bpf_link__fd(links[0]),
 195                               bpf_program__fd(skel->progs.egress_alt),
 196                               &link_upd_opts);
 197         if (CHECK(err == 0 || errno != EPERM, "prog_cmpxchg1",
 198                   "unexpectedly succeeded, err %d, errno %d\n", err, -errno))
 199                 goto cleanup;
 200
 201         /* Compare-exchange single link program from egress to egress_alt */
 202         link_upd_opts.old_prog_fd = bpf_program__fd(skel->progs.egress);
 203         link_upd_opts.flags = BPF_F_REPLACE;
 204         err = bpf_link_update(bpf_link__fd(links[0]),
 205                               bpf_program__fd(skel->progs.egress_alt),
 206                               &link_upd_opts);
 207         if (CHECK(err, "prog_cmpxchg2", "errno %d\n", -errno))
 208                 goto cleanup;
 209
 210         /* ping */
 211         ping_and_check(0, cg_nr);
 212
 213         /* close cgroup FDs before detaching links */
 214         for (i = 0; i < cg_nr; i++) {
 215                 if (cgs[i].fd > 0) {
 216                         close(cgs[i].fd);
 217                         cgs[i].fd = -1;
 218                 }
 219         }
 220
 221         /* BPF programs should still get called */
 222         ping_and_check(0, cg_nr);
 223
 224         prog_id = link_info_prog_id(links[0], &info);
 225         CHECK(prog_id == 0, "link_info", "failed\n");
 226         CHECK(info.cgroup.cgroup_id == 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
 227
 228         err = bpf_link__detach(links[0]);
 229         if (CHECK(err, "link_detach", "failed %d\n", err))
 230                 goto cleanup;
 231
 232         /* cgroup_id should be zero in link_info */
 233         prog_id = link_info_prog_id(links[0], &info);
 234         CHECK(prog_id == 0, "link_info", "failed\n");
 235         CHECK(info.cgroup.cgroup_id != 0, "cgroup_id", "unexpected %llu\n", info.cgroup.cgroup_id);
 236
 237         /* First BPF program shouldn't be called anymore */
 238         ping_and_check(0, cg_nr - 1);
 239
 240         /* leave cgroup and remove them, don't detach programs */
 241         cleanup_cgroup_environment();
 242
 243         /* BPF programs should have been auto-detached */
 244         ping_and_check(0, 0);
 245
 246 cleanup:
 247         if (detach_legacy)
 248                 bpf_prog_detach2(prog_fd, cgs[last_cg].fd,
 249                                  BPF_CGROUP_INET_EGRESS);
 250
 251         for (i = 0; i < cg_nr; i++) {
 252                 if (!IS_ERR(links[i]))
 253                         bpf_link__destroy(links[i]);
 254         }
 255         test_cgroup_link__destroy(skel);
 256
 257         for (i = 0; i < cg_nr; i++) {
 258                 if (cgs[i].fd > 0)
 259                         close(cgs[i].fd);
 260         }
 261         cleanup_cgroup_environment();
 262 }