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 > /dev/null"
  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 static int test_foo_bar(void)
  59 {
  60         int drop_prog, allow_prog, foo = 0, bar = 0, rc = 0;
  61
  62         allow_prog = prog_load(1);
  63         if (!allow_prog)
  64                 goto err;
  65
  66         drop_prog = prog_load(0);
  67         if (!drop_prog)
  68                 goto err;
  69
  70         if (setup_cgroup_environment())
  71                 goto err;
  72
  73         /* Create cgroup /foo, get fd, and join it */
  74         foo = create_and_get_cgroup(FOO);
  75         if (!foo)
  76                 goto err;
  77
  78         if (join_cgroup(FOO))
  79                 goto err;
  80
  81         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
  82                 log_err("Attaching prog to /foo");
  83                 goto err;
  84         }
  85
  86         printf("Attached DROP prog. This ping in cgroup /foo should fail...\n");
  87         assert(system(PING_CMD) != 0);
  88
  89         /* Create cgroup /foo/bar, get fd, and join it */
  90         bar = create_and_get_cgroup(BAR);
  91         if (!bar)
  92                 goto err;
  93
  94         if (join_cgroup(BAR))
  95                 goto err;
  96
  97         printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
  98         assert(system(PING_CMD) != 0);
  99
 100         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 101                 log_err("Attaching prog to /foo/bar");
 102                 goto err;
 103         }
 104
 105         printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
 106         assert(system(PING_CMD) == 0);
 107
 108         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 109                 log_err("Detaching program from /foo/bar");
 110                 goto err;
 111         }
 112
 113         printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
 114                "This ping in cgroup /foo/bar should fail...\n");
 115         assert(system(PING_CMD) != 0);
 116
 117         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 118                 log_err("Attaching prog to /foo/bar");
 119                 goto err;
 120         }
 121
 122         if (bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 123                 log_err("Detaching program from /foo");
 124                 goto err;
 125         }
 126
 127         printf("Attached PASS from /foo/bar and detached DROP from /foo.\n"
 128                "This ping in cgroup /foo/bar should pass...\n");
 129         assert(system(PING_CMD) == 0);
 130
 131         if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 132                 log_err("Attaching prog to /foo/bar");
 133                 goto err;
 134         }
 135
 136         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 137                 errno = 0;
 138                 log_err("Unexpected success attaching prog to /foo/bar");
 139                 goto err;
 140         }
 141
 142         if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
 143                 log_err("Detaching program from /foo/bar");
 144                 goto err;
 145         }
 146
 147         if (!bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
 148                 errno = 0;
 149                 log_err("Unexpected success in double detach from /foo");
 150                 goto err;
 151         }
 152
 153         if (bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 154                 log_err("Attaching non-overridable prog to /foo");
 155                 goto err;
 156         }
 157
 158         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
 159                 errno = 0;
 160                 log_err("Unexpected success attaching non-overridable prog to /foo/bar");
 161                 goto err;
 162         }
 163
 164         if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
 165                 errno = 0;
 166                 log_err("Unexpected success attaching overridable prog to /foo/bar");
 167                 goto err;
 168         }
 169
 170         if (!bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
 171                 errno = 0;
 172                 log_err("Unexpected success attaching overridable prog to /foo");
 173                 goto err;
 174         }
 175
 176         if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
 177                 log_err("Attaching different non-overridable prog to /foo");
 178                 goto err;
 179         }
 180
 181         goto out;
 182
 183 err:
 184         rc = 1;
 185
 186 out:
 187         close(foo);
 188         close(bar);
 189         cleanup_cgroup_environment();
 190         if (!rc)
 191                 printf("### override:PASS\n");
 192         else
 193                 printf("### override:FAIL\n");
 194         return rc;
 195 }
 196
 197 static int map_fd = -1;
 198
 199 static int prog_load_cnt(int verdict, int val)
 200 {
 201         if (map_fd < 0)
 202                 map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 8, 1, 0);
 203         if (map_fd < 0) {
 204                 printf("failed to create map '%s'\n", strerror(errno));
 205                 return -1;
 206         }
 207
 208         struct bpf_insn prog[] = {
 209                 BPF_MOV32_IMM(BPF_REG_0, 0),
 210                 BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
 211                 BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 212                 BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
 213                 BPF_LD_MAP_FD(BPF_REG_1, map_fd),
 214                 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
 215                 BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
 216                 BPF_MOV64_IMM(BPF_REG_1, val), /* r1 = 1 */
 217                 BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
 218                 BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
 219                 BPF_EXIT_INSN(),
 220         };
 221         size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
 222         int ret;
 223
 224         ret = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
 225                                prog, insns_cnt, "GPL", 0,
 226                                bpf_log_buf, BPF_LOG_BUF_SIZE);
 227
 228         if (ret < 0) {
 229                 log_err("Loading program");
 230                 printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
 231                 return 0;
 232         }
 233         return ret;
 234 }
 235
 236
 237 static int test_multiprog(void)
 238 {
 239         __u32 prog_ids[4], prog_cnt = 0, attach_flags, saved_prog_id;
 240         int cg1 = 0, cg2 = 0, cg3 = 0, cg4 = 0, cg5 = 0, key = 0;
 241         int drop_prog, allow_prog[6] = {}, rc = 0;
 242         unsigned long long value;
 243         int i = 0;
 244
 245         for (i = 0; i < 6; i++) {
 246                 allow_prog[i] = prog_load_cnt(1, 1 << i);
 247                 if (!allow_prog[i])
 248                         goto err;
 249         }
 250         drop_prog = prog_load_cnt(0, 1);
 251         if (!drop_prog)
 252                 goto err;
 253
 254         if (setup_cgroup_environment())
 255                 goto err;
 256
 257         cg1 = create_and_get_cgroup("/cg1");
 258         if (!cg1)
 259                 goto err;
 260         cg2 = create_and_get_cgroup("/cg1/cg2");
 261         if (!cg2)
 262                 goto err;
 263         cg3 = create_and_get_cgroup("/cg1/cg2/cg3");
 264         if (!cg3)
 265                 goto err;
 266         cg4 = create_and_get_cgroup("/cg1/cg2/cg3/cg4");
 267         if (!cg4)
 268                 goto err;
 269         cg5 = create_and_get_cgroup("/cg1/cg2/cg3/cg4/cg5");
 270         if (!cg5)
 271                 goto err;
 272
 273         if (join_cgroup("/cg1/cg2/cg3/cg4/cg5"))
 274                 goto err;
 275
 276         if (bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS, 2)) {
 277                 log_err("Attaching prog to cg1");
 278                 goto err;
 279         }
 280         if (!bpf_prog_attach(allow_prog[0], cg1, BPF_CGROUP_INET_EGRESS, 2)) {
 281                 log_err("Unexpected success attaching the same prog to cg1");
 282                 goto err;
 283         }
 284         if (bpf_prog_attach(allow_prog[1], cg1, BPF_CGROUP_INET_EGRESS, 2)) {
 285                 log_err("Attaching prog2 to cg1");
 286                 goto err;
 287         }
 288         if (bpf_prog_attach(allow_prog[2], cg2, BPF_CGROUP_INET_EGRESS, 1)) {
 289                 log_err("Attaching prog to cg2");
 290                 goto err;
 291         }
 292         if (bpf_prog_attach(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS, 2)) {
 293                 log_err("Attaching prog to cg3");
 294                 goto err;
 295         }
 296         if (bpf_prog_attach(allow_prog[4], cg4, BPF_CGROUP_INET_EGRESS, 1)) {
 297                 log_err("Attaching prog to cg4");
 298                 goto err;
 299         }
 300         if (bpf_prog_attach(allow_prog[5], cg5, BPF_CGROUP_INET_EGRESS, 0)) {
 301                 log_err("Attaching prog to cg5");
 302                 goto err;
 303         }
 304         assert(system(PING_CMD) == 0);
 305         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 306         assert(value == 1 + 2 + 8 + 32);
 307
 308         /* query the number of effective progs in cg5 */
 309         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 310                               NULL, NULL, &prog_cnt) == 0);
 311         assert(prog_cnt == 4);
 312         /* retrieve prog_ids of effective progs in cg5 */
 313         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 314                               &attach_flags, prog_ids, &prog_cnt) == 0);
 315         assert(prog_cnt == 4);
 316         assert(attach_flags == 0);
 317         saved_prog_id = prog_ids[0];
 318         /* check enospc handling */
 319         prog_ids[0] = 0;
 320         prog_cnt = 2;
 321         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 322                               &attach_flags, prog_ids, &prog_cnt) == -1 &&
 323                errno == ENOSPC);
 324         assert(prog_cnt == 4);
 325         /* check that prog_ids are returned even when buffer is too small */
 326         assert(prog_ids[0] == saved_prog_id);
 327         /* retrieve prog_id of single attached prog in cg5 */
 328         prog_ids[0] = 0;
 329         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0,
 330                               NULL, prog_ids, &prog_cnt) == 0);
 331         assert(prog_cnt == 1);
 332         assert(prog_ids[0] == saved_prog_id);
 333
 334         /* detach bottom program and ping again */
 335         if (bpf_prog_detach2(-1, cg5, BPF_CGROUP_INET_EGRESS)) {
 336                 log_err("Detaching prog from cg5");
 337                 goto err;
 338         }
 339         value = 0;
 340         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 341         assert(system(PING_CMD) == 0);
 342         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 343         assert(value == 1 + 2 + 8 + 16);
 344
 345         /* detach 3rd from bottom program and ping again */
 346         errno = 0;
 347         if (!bpf_prog_detach2(0, cg3, BPF_CGROUP_INET_EGRESS)) {
 348                 log_err("Unexpected success on detach from cg3");
 349                 goto err;
 350         }
 351         if (bpf_prog_detach2(allow_prog[3], cg3, BPF_CGROUP_INET_EGRESS)) {
 352                 log_err("Detaching from cg3");
 353                 goto err;
 354         }
 355         value = 0;
 356         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 357         assert(system(PING_CMD) == 0);
 358         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 359         assert(value == 1 + 2 + 16);
 360
 361         /* detach 2nd from bottom program and ping again */
 362         if (bpf_prog_detach2(-1, cg4, BPF_CGROUP_INET_EGRESS)) {
 363                 log_err("Detaching prog from cg4");
 364                 goto err;
 365         }
 366         value = 0;
 367         assert(bpf_map_update_elem(map_fd, &key, &value, 0) == 0);
 368         assert(system(PING_CMD) == 0);
 369         assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 370         assert(value == 1 + 2 + 4);
 371
 372         prog_cnt = 4;
 373         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, BPF_F_QUERY_EFFECTIVE,
 374                               &attach_flags, prog_ids, &prog_cnt) == 0);
 375         assert(prog_cnt == 3);
 376         assert(attach_flags == 0);
 377         assert(bpf_prog_query(cg5, BPF_CGROUP_INET_EGRESS, 0,
 378                               NULL, prog_ids, &prog_cnt) == 0);
 379         assert(prog_cnt == 0);
 380         goto out;
 381 err:
 382         rc = 1;
 383
 384 out:
 385         for (i = 0; i < 6; i++)
 386                 if (allow_prog[i] > 0)
 387                         close(allow_prog[i]);
 388         close(cg1);
 389         close(cg2);
 390         close(cg3);
 391         close(cg4);
 392         close(cg5);
 393         cleanup_cgroup_environment();
 394         if (!rc)
 395                 printf("### multi:PASS\n");
 396         else
 397                 printf("### multi:FAIL\n");
 398         return rc;
 399 }
 400
 401 int main(int argc, char **argv)
 402 {
 403         int rc = 0;
 404
 405         rc = test_foo_bar();
 406         if (rc)
 407                 return rc;
 408
 409         return test_multiprog();
 410 }