samples/bpf/test_cgrp2_attach2.c

   1 /* eBPF example program:
   2  *
   3  * - Creates arraymap in kernel with 4 bytes keys and 8 byte values
   4  *
   5  * - Loads eBPF program
   6  *
   7  *   The eBPF program accesses the map passed in to store two pieces of
   8  *   information. The number of invocations of the program, which maps
   9  *   to the number of packets received, is stored to key 0. Key 1 is
  10  *   incremented on each iteration by the number of bytes stored in
  11  *   the skb.
  12  *
  13  * - Attaches the new program to a cgroup using BPF_PROG_ATTACH
  14  *
  15  * - Every second, reads map[0] and map[1] to see how many bytes and
  16  *   packets were seen on any socket of tasks in the given cgroup.
  17  */
  18
  19 #define _GNU_SOURCE
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <assert.h>
  24 #include <unistd.h>
  25
  26 #include <linux/bpf.h>
  27
  28 #include "libbpf.h"
  29 #include "cgroup_helpers.h"
  30
  31 #define FOO             "/foo"
  32 #define BAR             "/foo/bar/"
  33 #define PING_CMD        "ping -c1 -w1 127.0.0.1"
  34
  35 char bpf_log_buf[BPF_LOG_BUF_SIZE];
  36
  37 static int prog_load(int verdict)
  38 {
  39         int ret;
  40         struct bpf_insn prog[] = {
  41                 BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
  42                 BPF_EXIT_INSN(),
  43         };
  44         size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
  45
  46         ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
  47                                prog, insns_cnt, "GPL", 0,
  48                                bpf_log_buf, BPF_LOG_BUF_SIZE);
  49
  50         if (ret < 0) {
  51                 log_err("Loading program");
  52                 printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
  53                 return 0;
  54         }
  55         return ret;
  56 }
  57
  58
  59 int main(int argc, char **argv)
  60 {
  61         int drop_prog, allow_prog, foo = 0, bar = 0, rc = 0;
  62
  63         allow_prog = prog_load(1);
  64         if (!allow_prog)
  65                 goto err;
  66
  67         drop_prog = prog_load(0);
  68         if (!drop_prog)
  69                 goto err;
  70
  71         if (setup_cgroup_environment())
  72                 goto err;
  73
  74         /* Create cgroup /foo, get fd, and join it */
  75         foo = create_and_get_cgroup(FOO);
  76         if (!foo)
  77                 goto err;
  78
  79         if (join_cgroup(FOO))
  80                 goto err;
  81
  82         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
  83                 log_err("Attaching prog to /foo");
  84                 goto err;
  85         }
  86
  87         printf("Attached DROP prog. This ping in cgroup /foo should fail...\n");
  88         assert(system(PING_CMD) != 0);
  89
  90         /* Create cgroup /foo/bar, get fd, and join it */
  91         bar = create_and_get_cgroup(BAR);
  92         if (!bar)
  93                 goto err;
  94
  95         if (join_cgroup(BAR))
  96                 goto err;
  97
  98         printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
  99         assert(system(PING_CMD) != 0);
 100
 101         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 102                 log_err("Attaching prog to /foo/bar");
 103                 goto err;
 104         }
 105
 106         printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
 107         assert(system(PING_CMD) == 0);
 108
 109         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 110                 log_err("Detaching program from /foo/bar");
 111                 goto err;
 112         }
 113
 114         printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
 115                "This ping in cgroup /foo/bar should fail...\n");
 116         assert(system(PING_CMD) != 0);
 117
 118         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 119                 log_err("Attaching prog to /foo/bar");
 120                 goto err;
 121         }
 122
 123         if (bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 124                 log_err("Detaching program from /foo");
 125                 goto err;
 126         }
 127
 128         printf("Attached PASS from /foo/bar and detached DROP from /foo.\n"
 129                "This ping in cgroup /foo/bar should pass...\n");
 130         assert(system(PING_CMD) == 0);
 131
 132         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 133                 log_err("Attaching prog to /foo/bar");
 134                 goto err;
 135         }
 136
 137         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 138                 errno = 0;
 139                 log_err("Unexpected success attaching prog to /foo/bar");
 140                 goto err;
 141         }
 142
 143         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 144                 log_err("Detaching program from /foo/bar");
 145                 goto err;
 146         }
 147
 148         if (!bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 149                 errno = 0;
 150                 log_err("Unexpected success in double detach from /foo");
 151                 goto err;
 152         }
 153
 154         if (bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 155                 log_err("Attaching non-overridable prog to /foo");
 156                 goto err;
 157         }
 158
 159         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 160                 errno = 0;
 161                 log_err("Unexpected success attaching non-overridable prog to /foo/bar");
 162                 goto err;
 163         }
 164
 165         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 166                 errno = 0;
 167                 log_err("Unexpected success attaching overridable prog to /foo/bar");
 168                 goto err;
 169         }
 170
 171         if (!bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
 172                 errno = 0;
 173                 log_err("Unexpected success attaching overridable prog to /foo");
 174                 goto err;
 175         }
 176
 177         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 178                 log_err("Attaching different non-overridable prog to /foo");
 179                 goto err;
 180         }
 181
 182         goto out;
 183
 184 err:
 185         rc = 1;
 186
 187 out:
 188         close(foo);
 189         close(bar);
 190         cleanup_cgroup_environment();
 191         if (!rc)
 192                 printf("PASS\n");
 193         else
 194                 printf("FAIL\n");
 195         return rc;
 196 }