selftest/bpf: Add various selftests for program limits

Add various tests to check maximum number of supported programs
being attached:

  # ./vmtest.sh -- ./test_progs -t tc_opts
  [...]
  ./test_progs -t tc_opts
  [    1.185325] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.186826] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.270123] tsc: Refined TSC clocksource calibration: 3407.988 MHz
  [    1.272428] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
  [    1.276408] clocksource: Switched to clocksource tsc
  #252     tc_opts_after:OK
  #253     tc_opts_append:OK
  #254     tc_opts_basic:OK
  #255     tc_opts_before:OK
  #256     tc_opts_chain_classic:OK
  #257     tc_opts_chain_mixed:OK
  #258     tc_opts_delete_empty:OK
  #259     tc_opts_demixed:OK
  #260     tc_opts_detach:OK
  #261     tc_opts_detach_after:OK
  #262     tc_opts_detach_before:OK
  #263     tc_opts_dev_cleanup:OK
  #264     tc_opts_invalid:OK
  #265     tc_opts_max:OK              <--- (new test)
  #266     tc_opts_mixed:OK
  #267     tc_opts_prepend:OK
  #268     tc_opts_replace:OK
  #269     tc_opts_revision:OK
  Summary: 18/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230929204121.20305-2-daniel@iogearbox.net

diff --git a/tools/testing/selftests/bpf/prog_tests/tc_opts.c b/tools/testing/selftests/bpf/prog_tests/tc_opts.c
index 7a2ecd4eca5dd397d317d488ab09038e898a87ba..99af79ea21a9ccb576f5a4fc8f4b004545642fa3 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/tc_opts.c
+++ b/tools/testing/selftests/bpf/prog_tests/tc_opts.c
@@ -2378,3 +2378,87 @@ void serial_test_tc_opts_chain_mixed(void)
        test_tc_chain_mixed(BPF_TCX_INGRESS);
        test_tc_chain_mixed(BPF_TCX_EGRESS);
 }
+
+static int generate_dummy_prog(void)
+{
+       const struct bpf_insn prog_insns[] = {
+               BPF_MOV64_IMM(BPF_REG_0, 0),
+               BPF_EXIT_INSN(),
+       };
+       const size_t prog_insn_cnt = sizeof(prog_insns) / sizeof(struct bpf_insn);
+       LIBBPF_OPTS(bpf_prog_load_opts, opts);
+       const size_t log_buf_sz = 256;
+       char *log_buf;
+       int fd = -1;
+
+       log_buf = malloc(log_buf_sz);
+       if (!ASSERT_OK_PTR(log_buf, "log_buf_alloc"))
+               return fd;
+       opts.log_buf = log_buf;
+       opts.log_size = log_buf_sz;
+
+       log_buf[0] = '\0';
+       opts.log_level = 0;
+       fd = bpf_prog_load(BPF_PROG_TYPE_SCHED_CLS, "tcx_prog", "GPL",
+                          prog_insns, prog_insn_cnt, &opts);
+       ASSERT_STREQ(log_buf, "", "log_0");
+       ASSERT_GE(fd, 0, "prog_fd");
+       free(log_buf);
+       return fd;
+}
+
+static void test_tc_opts_max_target(int target, int flags, bool relative)
+{
+       int err, ifindex, i, prog_fd, last_fd = -1;
+       LIBBPF_OPTS(bpf_prog_attach_opts, opta);
+       const int max_progs = 63;
+
+       ASSERT_OK(system("ip link add dev tcx_opts1 type veth peer name tcx_opts2"), "add veth");
+       ifindex = if_nametoindex("tcx_opts1");
+       ASSERT_NEQ(ifindex, 0, "non_zero_ifindex");
+
+       assert_mprog_count_ifindex(ifindex, target, 0);
+
+       for (i = 0; i < max_progs; i++) {
+               prog_fd = generate_dummy_prog();
+               if (!ASSERT_GE(prog_fd, 0, "dummy_prog"))
+                       goto cleanup;
+               err = bpf_prog_attach_opts(prog_fd, ifindex, target, &opta);
+               if (!ASSERT_EQ(err, 0, "prog_attach"))
+                       goto cleanup;
+               assert_mprog_count_ifindex(ifindex, target, i + 1);
+               if (i == max_progs - 1 && relative)
+                       last_fd = prog_fd;
+               else
+                       close(prog_fd);
+       }
+
+       prog_fd = generate_dummy_prog();
+       if (!ASSERT_GE(prog_fd, 0, "dummy_prog"))
+               goto cleanup;
+       opta.flags = flags;
+       if (last_fd > 0)
+               opta.relative_fd = last_fd;
+       err = bpf_prog_attach_opts(prog_fd, ifindex, target, &opta);
+       ASSERT_EQ(err, -ERANGE, "prog_64_attach");
+       assert_mprog_count_ifindex(ifindex, target, max_progs);
+       close(prog_fd);
+cleanup:
+       if (last_fd > 0)
+               close(last_fd);
+       ASSERT_OK(system("ip link del dev tcx_opts1"), "del veth");
+       ASSERT_EQ(if_nametoindex("tcx_opts1"), 0, "dev1_removed");
+       ASSERT_EQ(if_nametoindex("tcx_opts2"), 0, "dev2_removed");
+}
+
+void serial_test_tc_opts_max(void)
+{
+       test_tc_opts_max_target(BPF_TCX_INGRESS, 0, false);
+       test_tc_opts_max_target(BPF_TCX_EGRESS, 0, false);
+
+       test_tc_opts_max_target(BPF_TCX_INGRESS, BPF_F_BEFORE, false);
+       test_tc_opts_max_target(BPF_TCX_EGRESS, BPF_F_BEFORE, true);
+
+       test_tc_opts_max_target(BPF_TCX_INGRESS, BPF_F_AFTER, true);
+       test_tc_opts_max_target(BPF_TCX_EGRESS, BPF_F_AFTER, false);
+}