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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Facebook */
   3 #include <uapi/linux/if_link.h>
   4 #include <test_progs.h>
   5 #include "test_xdp_link.skel.h"
   6
   7 #define IFINDEX_LO 1
   8
   9 void test_xdp_link(void)
  10 {
  11         __u32 duration = 0, id1, id2, id0 = 0, prog_fd1, prog_fd2, err;
  12         DECLARE_LIBBPF_OPTS(bpf_xdp_set_link_opts, opts, .old_fd = -1);
  13         struct test_xdp_link *skel1 = NULL, *skel2 = NULL;
  14         struct bpf_link_info link_info;
  15         struct bpf_prog_info prog_info;
  16         struct bpf_link *link;
  17         __u32 link_info_len = sizeof(link_info);
  18         __u32 prog_info_len = sizeof(prog_info);
  19
  20         skel1 = test_xdp_link__open_and_load();
  21         if (CHECK(!skel1, "skel_load", "skeleton open and load failed\n"))
  22                 goto cleanup;
  23         prog_fd1 = bpf_program__fd(skel1->progs.xdp_handler);
  24
  25         skel2 = test_xdp_link__open_and_load();
  26         if (CHECK(!skel2, "skel_load", "skeleton open and load failed\n"))
  27                 goto cleanup;
  28         prog_fd2 = bpf_program__fd(skel2->progs.xdp_handler);
  29
  30         memset(&prog_info, 0, sizeof(prog_info));
  31         err = bpf_obj_get_info_by_fd(prog_fd1, &prog_info, &prog_info_len);
  32         if (CHECK(err, "fd_info1", "failed %d\n", -errno))
  33                 goto cleanup;
  34         id1 = prog_info.id;
  35
  36         memset(&prog_info, 0, sizeof(prog_info));
  37         err = bpf_obj_get_info_by_fd(prog_fd2, &prog_info, &prog_info_len);
  38         if (CHECK(err, "fd_info2", "failed %d\n", -errno))
  39                 goto cleanup;
  40         id2 = prog_info.id;
  41
  42         /* set initial prog attachment */
  43         err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd1, XDP_FLAGS_REPLACE, &opts);
  44         if (CHECK(err, "fd_attach", "initial prog attach failed: %d\n", err))
  45                 goto cleanup;
  46
  47         /* validate prog ID */
  48         err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
  49         CHECK(err || id0 != id1, "id1_check",
  50               "loaded prog id %u != id1 %u, err %d", id0, id1, err);
  51
  52         /* BPF link is not allowed to replace prog attachment */
  53         link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
  54         if (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
  55                 bpf_link__destroy(link);
  56                 /* best-effort detach prog */
  57                 opts.old_fd = prog_fd1;
  58                 bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
  59                 goto cleanup;
  60         }
  61
  62         /* detach BPF program */
  63         opts.old_fd = prog_fd1;
  64         err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, -1, XDP_FLAGS_REPLACE, &opts);
  65         if (CHECK(err, "prog_detach", "failed %d\n", err))
  66                 goto cleanup;
  67
  68         /* now BPF link should attach successfully */
  69         link = bpf_program__attach_xdp(skel1->progs.xdp_handler, IFINDEX_LO);
  70         if (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
  71                 goto cleanup;
  72         skel1->links.xdp_handler = link;
  73
  74         /* validate prog ID */
  75         err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
  76         if (CHECK(err || id0 != id1, "id1_check",
  77                   "loaded prog id %u != id1 %u, err %d", id0, id1, err))
  78                 goto cleanup;
  79
  80         /* BPF prog attach is not allowed to replace BPF link */
  81         opts.old_fd = prog_fd1;
  82         err = bpf_set_link_xdp_fd_opts(IFINDEX_LO, prog_fd2, XDP_FLAGS_REPLACE, &opts);
  83         if (CHECK(!err, "prog_attach_fail", "unexpected success\n"))
  84                 goto cleanup;
  85
  86         /* Can't force-update when BPF link is active */
  87         err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd2, 0);
  88         if (CHECK(!err, "prog_update_fail", "unexpected success\n"))
  89                 goto cleanup;
  90
  91         /* Can't force-detach when BPF link is active */
  92         err = bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
  93         if (CHECK(!err, "prog_detach_fail", "unexpected success\n"))
  94                 goto cleanup;
  95
  96         /* BPF link is not allowed to replace another BPF link */
  97         link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
  98         if (CHECK(!IS_ERR(link), "link_attach_fail", "unexpected success\n")) {
  99                 bpf_link__destroy(link);
 100                 goto cleanup;
 101         }
 102
 103         bpf_link__destroy(skel1->links.xdp_handler);
 104         skel1->links.xdp_handler = NULL;
 105
 106         /* new link attach should succeed */
 107         link = bpf_program__attach_xdp(skel2->progs.xdp_handler, IFINDEX_LO);
 108         if (CHECK(IS_ERR(link), "link_attach", "failed: %ld\n", PTR_ERR(link)))
 109                 goto cleanup;
 110         skel2->links.xdp_handler = link;
 111
 112         err = bpf_get_link_xdp_id(IFINDEX_LO, &id0, 0);
 113         if (CHECK(err || id0 != id2, "id2_check",
 114                   "loaded prog id %u != id2 %u, err %d", id0, id1, err))
 115                 goto cleanup;
 116
 117         /* updating program under active BPF link works as expected */
 118         err = bpf_link__update_program(link, skel1->progs.xdp_handler);
 119         if (CHECK(err, "link_upd", "failed: %d\n", err))
 120                 goto cleanup;
 121
 122         memset(&link_info, 0, sizeof(link_info));
 123         err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
 124         if (CHECK(err, "link_info", "failed: %d\n", err))
 125                 goto cleanup;
 126
 127         CHECK(link_info.type != BPF_LINK_TYPE_XDP, "link_type",
 128               "got %u != exp %u\n", link_info.type, BPF_LINK_TYPE_XDP);
 129         CHECK(link_info.prog_id != id1, "link_prog_id",
 130               "got %u != exp %u\n", link_info.prog_id, id1);
 131         CHECK(link_info.xdp.ifindex != IFINDEX_LO, "link_ifindex",
 132               "got %u != exp %u\n", link_info.xdp.ifindex, IFINDEX_LO);
 133
 134         err = bpf_link__detach(link);
 135         if (CHECK(err, "link_detach", "failed %d\n", err))
 136                 goto cleanup;
 137
 138         memset(&link_info, 0, sizeof(link_info));
 139         err = bpf_obj_get_info_by_fd(bpf_link__fd(link), &link_info, &link_info_len);
 140         if (CHECK(err, "link_info", "failed: %d\n", err))
 141                 goto cleanup;
 142         CHECK(link_info.prog_id != id1, "link_prog_id",
 143               "got %u != exp %u\n", link_info.prog_id, id1);
 144         /* ifindex should be zeroed out */
 145         CHECK(link_info.xdp.ifindex != 0, "link_ifindex",
 146               "got %u != exp %u\n", link_info.xdp.ifindex, 0);
 147
 148 cleanup:
 149         test_xdp_link__destroy(skel1);
 150         test_xdp_link__destroy(skel2);
 151 }