tools/testing/selftests/bpf/xdp_synproxy.c

   1 // SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
   2 /* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
   3
   4 #include <stdnoreturn.h>
   5 #include <stdlib.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <unistd.h>
  10 #include <getopt.h>
  11 #include <signal.h>
  12 #include <sys/types.h>
  13 #include <bpf/bpf.h>
  14 #include <bpf/libbpf.h>
  15 #include <net/if.h>
  16 #include <linux/if_link.h>
  17 #include <linux/limits.h>
  18
  19 static unsigned int ifindex;
  20 static __u32 attached_prog_id;
  21 static bool attached_tc;
  22
  23 static void noreturn cleanup(int sig)
  24 {
  25         LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
  26         int prog_fd;
  27         int err;
  28
  29         if (attached_prog_id == 0)
  30                 exit(0);
  31
  32         if (attached_tc) {
  33                 LIBBPF_OPTS(bpf_tc_hook, hook,
  34                             .ifindex = ifindex,
  35                             .attach_point = BPF_TC_INGRESS);
  36
  37                 err = bpf_tc_hook_destroy(&hook);
  38                 if (err < 0) {
  39                         fprintf(stderr, "Error: bpf_tc_hook_destroy: %s\n", strerror(-err));
  40                         fprintf(stderr, "Failed to destroy the TC hook\n");
  41                         exit(1);
  42                 }
  43                 exit(0);
  44         }
  45
  46         prog_fd = bpf_prog_get_fd_by_id(attached_prog_id);
  47         if (prog_fd < 0) {
  48                 fprintf(stderr, "Error: bpf_prog_get_fd_by_id: %s\n", strerror(-prog_fd));
  49                 err = bpf_xdp_attach(ifindex, -1, 0, NULL);
  50                 if (err < 0) {
  51                         fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n", strerror(-err));
  52                         fprintf(stderr, "Failed to detach XDP program\n");
  53                         exit(1);
  54                 }
  55         } else {
  56                 opts.old_prog_fd = prog_fd;
  57                 err = bpf_xdp_attach(ifindex, -1, XDP_FLAGS_REPLACE, &opts);
  58                 close(prog_fd);
  59                 if (err < 0) {
  60                         fprintf(stderr, "Error: bpf_set_link_xdp_fd_opts: %s\n", strerror(-err));
  61                         /* Not an error if already replaced by someone else. */
  62                         if (err != -EEXIST) {
  63                                 fprintf(stderr, "Failed to detach XDP program\n");
  64                                 exit(1);
  65                         }
  66                 }
  67         }
  68         exit(0);
  69 }
  70
  71 static noreturn void usage(const char *progname)
  72 {
  73         fprintf(stderr, "Usage: %s [--iface <iface>|--prog <prog_id>] [--mss4 <mss ipv4> --mss6 <mss ipv6> --wscale <wscale> --ttl <ttl>] [--ports <port1>,<port2>,...] [--single] [--tc]\n",
  74                 progname);
  75         exit(1);
  76 }
  77
  78 static unsigned long parse_arg_ul(const char *progname, const char *arg, unsigned long limit)
  79 {
  80         unsigned long res;
  81         char *endptr;
  82
  83         errno = 0;
  84         res = strtoul(arg, &endptr, 10);
  85         if (errno != 0 || *endptr != '\0' || arg[0] == '\0' || res > limit)
  86                 usage(progname);
  87
  88         return res;
  89 }
  90
  91 static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *prog_id,
  92                           __u64 *tcpipopts, char **ports, bool *single, bool *tc)
  93 {
  94         static struct option long_options[] = {
  95                 { "help", no_argument, NULL, 'h' },
  96                 { "iface", required_argument, NULL, 'i' },
  97                 { "prog", required_argument, NULL, 'x' },
  98                 { "mss4", required_argument, NULL, 4 },
  99                 { "mss6", required_argument, NULL, 6 },
 100                 { "wscale", required_argument, NULL, 'w' },
 101                 { "ttl", required_argument, NULL, 't' },
 102                 { "ports", required_argument, NULL, 'p' },
 103                 { "single", no_argument, NULL, 's' },
 104                 { "tc", no_argument, NULL, 'c' },
 105                 { NULL, 0, NULL, 0 },
 106         };
 107         unsigned long mss4, wscale, ttl;
 108         unsigned long long mss6;
 109         unsigned int tcpipopts_mask = 0;
 110
 111         if (argc < 2)
 112                 usage(argv[0]);
 113
 114         *ifindex = 0;
 115         *prog_id = 0;
 116         *tcpipopts = 0;
 117         *ports = NULL;
 118         *single = false;
 119         *tc = false;
 120
 121         while (true) {
 122                 int opt;
 123
 124                 opt = getopt_long(argc, argv, "", long_options, NULL);
 125                 if (opt == -1)
 126                         break;
 127
 128                 switch (opt) {
 129                 case 'h':
 130                         usage(argv[0]);
 131                         break;
 132                 case 'i':
 133                         *ifindex = if_nametoindex(optarg);
 134                         if (*ifindex == 0)
 135                                 usage(argv[0]);
 136                         break;
 137                 case 'x':
 138                         *prog_id = parse_arg_ul(argv[0], optarg, UINT32_MAX);
 139                         if (*prog_id == 0)
 140                                 usage(argv[0]);
 141                         break;
 142                 case 4:
 143                         mss4 = parse_arg_ul(argv[0], optarg, UINT16_MAX);
 144                         tcpipopts_mask |= 1 << 0;
 145                         break;
 146                 case 6:
 147                         mss6 = parse_arg_ul(argv[0], optarg, UINT16_MAX);
 148                         tcpipopts_mask |= 1 << 1;
 149                         break;
 150                 case 'w':
 151                         wscale = parse_arg_ul(argv[0], optarg, 14);
 152                         tcpipopts_mask |= 1 << 2;
 153                         break;
 154                 case 't':
 155                         ttl = parse_arg_ul(argv[0], optarg, UINT8_MAX);
 156                         tcpipopts_mask |= 1 << 3;
 157                         break;
 158                 case 'p':
 159                         *ports = optarg;
 160                         break;
 161                 case 's':
 162                         *single = true;
 163                         break;
 164                 case 'c':
 165                         *tc = true;
 166                         break;
 167                 default:
 168                         usage(argv[0]);
 169                 }
 170         }
 171         if (optind < argc)
 172                 usage(argv[0]);
 173
 174         if (tcpipopts_mask == 0xf) {
 175                 if (mss4 == 0 || mss6 == 0 || wscale == 0 || ttl == 0)
 176                         usage(argv[0]);
 177                 *tcpipopts = (mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;
 178         } else if (tcpipopts_mask != 0) {
 179                 usage(argv[0]);
 180         }
 181
 182         if (*ifindex != 0 && *prog_id != 0)
 183                 usage(argv[0]);
 184         if (*ifindex == 0 && *prog_id == 0)
 185                 usage(argv[0]);
 186 }
 187
 188 static int syncookie_attach(const char *argv0, unsigned int ifindex, bool tc)
 189 {
 190         struct bpf_prog_info info = {};
 191         __u32 info_len = sizeof(info);
 192         char xdp_filename[PATH_MAX];
 193         struct bpf_program *prog;
 194         struct bpf_object *obj;
 195         int prog_fd;
 196         int err;
 197
 198         snprintf(xdp_filename, sizeof(xdp_filename), "%s_kern.bpf.o", argv0);
 199         obj = bpf_object__open_file(xdp_filename, NULL);
 200         err = libbpf_get_error(obj);
 201         if (err < 0) {
 202                 fprintf(stderr, "Error: bpf_object__open_file: %s\n", strerror(-err));
 203                 return err;
 204         }
 205
 206         err = bpf_object__load(obj);
 207         if (err < 0) {
 208                 fprintf(stderr, "Error: bpf_object__open_file: %s\n", strerror(-err));
 209                 return err;
 210         }
 211
 212         prog = bpf_object__find_program_by_name(obj, tc ? "syncookie_tc" : "syncookie_xdp");
 213         if (!prog) {
 214                 fprintf(stderr, "Error: bpf_object__find_program_by_name: program was not found\n");
 215                 return -ENOENT;
 216         }
 217
 218         prog_fd = bpf_program__fd(prog);
 219
 220         err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
 221         if (err < 0) {
 222                 fprintf(stderr, "Error: bpf_prog_get_info_by_fd: %s\n",
 223                         strerror(-err));
 224                 goto out;
 225         }
 226         attached_tc = tc;
 227         attached_prog_id = info.id;
 228         signal(SIGINT, cleanup);
 229         signal(SIGTERM, cleanup);
 230         if (tc) {
 231                 LIBBPF_OPTS(bpf_tc_hook, hook,
 232                             .ifindex = ifindex,
 233                             .attach_point = BPF_TC_INGRESS);
 234                 LIBBPF_OPTS(bpf_tc_opts, opts,
 235                             .handle = 1,
 236                             .priority = 1,
 237                             .prog_fd = prog_fd);
 238
 239                 err = bpf_tc_hook_create(&hook);
 240                 if (err < 0) {
 241                         fprintf(stderr, "Error: bpf_tc_hook_create: %s\n",
 242                                 strerror(-err));
 243                         goto fail;
 244                 }
 245                 err = bpf_tc_attach(&hook, &opts);
 246                 if (err < 0) {
 247                         fprintf(stderr, "Error: bpf_tc_attach: %s\n",
 248                                 strerror(-err));
 249                         goto fail;
 250                 }
 251
 252         } else {
 253                 err = bpf_xdp_attach(ifindex, prog_fd,
 254                                      XDP_FLAGS_UPDATE_IF_NOEXIST, NULL);
 255                 if (err < 0) {
 256                         fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n",
 257                                 strerror(-err));
 258                         goto fail;
 259                 }
 260         }
 261         err = 0;
 262 out:
 263         bpf_object__close(obj);
 264         return err;
 265 fail:
 266         signal(SIGINT, SIG_DFL);
 267         signal(SIGTERM, SIG_DFL);
 268         attached_prog_id = 0;
 269         goto out;
 270 }
 271
 272 static int syncookie_open_bpf_maps(__u32 prog_id, int *values_map_fd, int *ports_map_fd)
 273 {
 274         struct bpf_prog_info prog_info;
 275         __u32 map_ids[8];
 276         __u32 info_len;
 277         int prog_fd;
 278         int err;
 279         int i;
 280
 281         *values_map_fd = -1;
 282         *ports_map_fd = -1;
 283
 284         prog_fd = bpf_prog_get_fd_by_id(prog_id);
 285         if (prog_fd < 0) {
 286                 fprintf(stderr, "Error: bpf_prog_get_fd_by_id: %s\n", strerror(-prog_fd));
 287                 return prog_fd;
 288         }
 289
 290         prog_info = (struct bpf_prog_info) {
 291                 .nr_map_ids = 8,
 292                 .map_ids = (__u64)(unsigned long)map_ids,
 293         };
 294         info_len = sizeof(prog_info);
 295
 296         err = bpf_prog_get_info_by_fd(prog_fd, &prog_info, &info_len);
 297         if (err != 0) {
 298                 fprintf(stderr, "Error: bpf_prog_get_info_by_fd: %s\n",
 299                         strerror(-err));
 300                 goto out;
 301         }
 302
 303         if (prog_info.nr_map_ids < 2) {
 304                 fprintf(stderr, "Error: Found %u BPF maps, expected at least 2\n",
 305                         prog_info.nr_map_ids);
 306                 err = -ENOENT;
 307                 goto out;
 308         }
 309
 310         for (i = 0; i < prog_info.nr_map_ids; i++) {
 311                 struct bpf_map_info map_info = {};
 312                 int map_fd;
 313
 314                 err = bpf_map_get_fd_by_id(map_ids[i]);
 315                 if (err < 0) {
 316                         fprintf(stderr, "Error: bpf_map_get_fd_by_id: %s\n", strerror(-err));
 317                         goto err_close_map_fds;
 318                 }
 319                 map_fd = err;
 320
 321                 info_len = sizeof(map_info);
 322                 err = bpf_map_get_info_by_fd(map_fd, &map_info, &info_len);
 323                 if (err != 0) {
 324                         fprintf(stderr, "Error: bpf_map_get_info_by_fd: %s\n",
 325                                 strerror(-err));
 326                         close(map_fd);
 327                         goto err_close_map_fds;
 328                 }
 329                 if (strcmp(map_info.name, "values") == 0) {
 330                         *values_map_fd = map_fd;
 331                         continue;
 332                 }
 333                 if (strcmp(map_info.name, "allowed_ports") == 0) {
 334                         *ports_map_fd = map_fd;
 335                         continue;
 336                 }
 337                 close(map_fd);
 338         }
 339
 340         if (*values_map_fd != -1 && *ports_map_fd != -1) {
 341                 err = 0;
 342                 goto out;
 343         }
 344
 345         err = -ENOENT;
 346
 347 err_close_map_fds:
 348         if (*values_map_fd != -1)
 349                 close(*values_map_fd);
 350         if (*ports_map_fd != -1)
 351                 close(*ports_map_fd);
 352         *values_map_fd = -1;
 353         *ports_map_fd = -1;
 354
 355 out:
 356         close(prog_fd);
 357         return err;
 358 }
 359
 360 int main(int argc, char *argv[])
 361 {
 362         int values_map_fd, ports_map_fd;
 363         __u64 tcpipopts;
 364         bool firstiter;
 365         __u64 prevcnt;
 366         __u32 prog_id;
 367         char *ports;
 368         bool single;
 369         int err = 0;
 370         bool tc;
 371
 372         parse_options(argc, argv, &ifindex, &prog_id, &tcpipopts, &ports,
 373                       &single, &tc);
 374
 375         if (prog_id == 0) {
 376                 if (!tc) {
 377                         err = bpf_xdp_query_id(ifindex, 0, &prog_id);
 378                         if (err < 0) {
 379                                 fprintf(stderr, "Error: bpf_get_link_xdp_id: %s\n",
 380                                         strerror(-err));
 381                                 goto out;
 382                         }
 383                 }
 384                 if (prog_id == 0) {
 385                         err = syncookie_attach(argv[0], ifindex, tc);
 386                         if (err < 0)
 387                                 goto out;
 388                         prog_id = attached_prog_id;
 389                 }
 390         }
 391
 392         err = syncookie_open_bpf_maps(prog_id, &values_map_fd, &ports_map_fd);
 393         if (err < 0)
 394                 goto out;
 395
 396         if (ports) {
 397                 __u16 port_last = 0;
 398                 __u32 port_idx = 0;
 399                 char *p = ports;
 400
 401                 fprintf(stderr, "Replacing allowed ports\n");
 402
 403                 while (p && *p != '\0') {
 404                         char *token = strsep(&p, ",");
 405                         __u16 port;
 406
 407                         port = parse_arg_ul(argv[0], token, UINT16_MAX);
 408                         err = bpf_map_update_elem(ports_map_fd, &port_idx, &port, BPF_ANY);
 409                         if (err != 0) {
 410                                 fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
 411                                 fprintf(stderr, "Failed to add port %u (index %u)\n",
 412                                         port, port_idx);
 413                                 goto out_close_maps;
 414                         }
 415                         fprintf(stderr, "Added port %u\n", port);
 416                         port_idx++;
 417                 }
 418                 err = bpf_map_update_elem(ports_map_fd, &port_idx, &port_last, BPF_ANY);
 419                 if (err != 0) {
 420                         fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
 421                         fprintf(stderr, "Failed to add the terminator value 0 (index %u)\n",
 422                                 port_idx);
 423                         goto out_close_maps;
 424                 }
 425         }
 426
 427         if (tcpipopts) {
 428                 __u32 key = 0;
 429
 430                 fprintf(stderr, "Replacing TCP/IP options\n");
 431
 432                 err = bpf_map_update_elem(values_map_fd, &key, &tcpipopts, BPF_ANY);
 433                 if (err != 0) {
 434                         fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
 435                         goto out_close_maps;
 436                 }
 437         }
 438
 439         if ((ports || tcpipopts) && attached_prog_id == 0 && !single)
 440                 goto out_close_maps;
 441
 442         prevcnt = 0;
 443         firstiter = true;
 444         while (true) {
 445                 __u32 key = 1;
 446                 __u64 value;
 447
 448                 err = bpf_map_lookup_elem(values_map_fd, &key, &value);
 449                 if (err != 0) {
 450                         fprintf(stderr, "Error: bpf_map_lookup_elem: %s\n", strerror(-err));
 451                         goto out_close_maps;
 452                 }
 453                 if (firstiter) {
 454                         prevcnt = value;
 455                         firstiter = false;
 456                 }
 457                 if (single) {
 458                         printf("Total SYNACKs generated: %llu\n", value);
 459                         break;
 460                 }
 461                 printf("SYNACKs generated: %llu (total %llu)\n", value - prevcnt, value);
 462                 prevcnt = value;
 463                 sleep(1);
 464         }
 465
 466 out_close_maps:
 467         close(values_map_fd);
 468         close(ports_map_fd);
 469 out:
 470         return err == 0 ? 0 : 1;
 471 }