net/sched/cls_bpf.c

   1 /*
   2  * Berkeley Packet Filter based traffic classifier
   3  *
   4  * Might be used to classify traffic through flexible, user-defined and
   5  * possibly JIT-ed BPF filters for traffic control as an alternative to
   6  * ematches.
   7  *
   8  * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/filter.h>
  19 #include <linux/bpf.h>
  20
  21 #include <net/rtnetlink.h>
  22 #include <net/pkt_cls.h>
  23 #include <net/sock.h>
  24
  25 MODULE_LICENSE("GPL");
  26 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
  27 MODULE_DESCRIPTION("TC BPF based classifier");
  28
  29 #define CLS_BPF_NAME_LEN        256
  30 #define CLS_BPF_SUPPORTED_GEN_FLAGS             \
  31         (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
  32
  33 struct cls_bpf_head {
  34         struct list_head plist;
  35         u32 hgen;
  36         struct rcu_head rcu;
  37 };
  38
  39 struct cls_bpf_prog {
  40         struct bpf_prog *filter;
  41         struct list_head link;
  42         struct tcf_result res;
  43         bool exts_integrated;
  44         bool offloaded;
  45         u32 gen_flags;
  46         struct tcf_exts exts;
  47         u32 handle;
  48         union {
  49                 u32 bpf_fd;
  50                 u16 bpf_num_ops;
  51         };
  52         struct sock_filter *bpf_ops;
  53         const char *bpf_name;
  54         struct tcf_proto *tp;
  55         struct rcu_head rcu;
  56 };
  57
  58 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
  59         [TCA_BPF_CLASSID]       = { .type = NLA_U32 },
  60         [TCA_BPF_FLAGS]         = { .type = NLA_U32 },
  61         [TCA_BPF_FLAGS_GEN]     = { .type = NLA_U32 },
  62         [TCA_BPF_FD]            = { .type = NLA_U32 },
  63         [TCA_BPF_NAME]          = { .type = NLA_NUL_STRING,
  64                                     .len = CLS_BPF_NAME_LEN },
  65         [TCA_BPF_OPS_LEN]       = { .type = NLA_U16 },
  66         [TCA_BPF_OPS]           = { .type = NLA_BINARY,
  67                                     .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
  68 };
  69
  70 static int cls_bpf_exec_opcode(int code)
  71 {
  72         switch (code) {
  73         case TC_ACT_OK:
  74         case TC_ACT_SHOT:
  75         case TC_ACT_STOLEN:
  76         case TC_ACT_REDIRECT:
  77         case TC_ACT_UNSPEC:
  78                 return code;
  79         default:
  80                 return TC_ACT_UNSPEC;
  81         }
  82 }
  83
  84 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  85                             struct tcf_result *res)
  86 {
  87         struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
  88         bool at_ingress = skb_at_tc_ingress(skb);
  89         struct cls_bpf_prog *prog;
  90         int ret = -1;
  91
  92         /* Needed here for accessing maps. */
  93         rcu_read_lock();
  94         list_for_each_entry_rcu(prog, &head->plist, link) {
  95                 int filter_res;
  96
  97                 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
  98
  99                 if (tc_skip_sw(prog->gen_flags)) {
 100                         filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
 101                 } else if (at_ingress) {
 102                         /* It is safe to push/pull even if skb_shared() */
 103                         __skb_push(skb, skb->mac_len);
 104                         bpf_compute_data_end(skb);
 105                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 106                         __skb_pull(skb, skb->mac_len);
 107                 } else {
 108                         bpf_compute_data_end(skb);
 109                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 110                 }
 111
 112                 if (prog->exts_integrated) {
 113                         res->class   = 0;
 114                         res->classid = TC_H_MAJ(prog->res.classid) |
 115                                        qdisc_skb_cb(skb)->tc_classid;
 116
 117                         ret = cls_bpf_exec_opcode(filter_res);
 118                         if (ret == TC_ACT_UNSPEC)
 119                                 continue;
 120                         break;
 121                 }
 122
 123                 if (filter_res == 0)
 124                         continue;
 125                 if (filter_res != -1) {
 126                         res->class   = 0;
 127                         res->classid = filter_res;
 128                 } else {
 129                         *res = prog->res;
 130                 }
 131
 132                 ret = tcf_exts_exec(skb, &prog->exts, res);
 133                 if (ret < 0)
 134                         continue;
 135
 136                 break;
 137         }
 138         rcu_read_unlock();
 139
 140         return ret;
 141 }
 142
 143 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
 144 {
 145         return !prog->bpf_ops;
 146 }
 147
 148 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 149                                enum tc_clsbpf_command cmd)
 150 {
 151         struct net_device *dev = tp->q->dev_queue->dev;
 152         struct tc_cls_bpf_offload bpf_offload = {};
 153         struct tc_to_netdev offload;
 154
 155         offload.type = TC_SETUP_CLSBPF;
 156         offload.cls_bpf = &bpf_offload;
 157
 158         bpf_offload.command = cmd;
 159         bpf_offload.exts = &prog->exts;
 160         bpf_offload.prog = prog->filter;
 161         bpf_offload.name = prog->bpf_name;
 162         bpf_offload.exts_integrated = prog->exts_integrated;
 163         bpf_offload.gen_flags = prog->gen_flags;
 164
 165         return dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
 166                                              tp->protocol, &offload);
 167 }
 168
 169 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 170                            struct cls_bpf_prog *oldprog)
 171 {
 172         struct net_device *dev = tp->q->dev_queue->dev;
 173         struct cls_bpf_prog *obj = prog;
 174         enum tc_clsbpf_command cmd;
 175         bool skip_sw;
 176         int ret;
 177
 178         skip_sw = tc_skip_sw(prog->gen_flags) ||
 179                 (oldprog && tc_skip_sw(oldprog->gen_flags));
 180
 181         if (oldprog && oldprog->offloaded) {
 182                 if (tc_should_offload(dev, tp, prog->gen_flags)) {
 183                         cmd = TC_CLSBPF_REPLACE;
 184                 } else if (!tc_skip_sw(prog->gen_flags)) {
 185                         obj = oldprog;
 186                         cmd = TC_CLSBPF_DESTROY;
 187                 } else {
 188                         return -EINVAL;
 189                 }
 190         } else {
 191                 if (!tc_should_offload(dev, tp, prog->gen_flags))
 192                         return skip_sw ? -EINVAL : 0;
 193                 cmd = TC_CLSBPF_ADD;
 194         }
 195
 196         ret = cls_bpf_offload_cmd(tp, obj, cmd);
 197         if (ret)
 198                 return skip_sw ? ret : 0;
 199
 200         obj->offloaded = true;
 201         if (oldprog)
 202                 oldprog->offloaded = false;
 203
 204         return 0;
 205 }
 206
 207 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 208                                  struct cls_bpf_prog *prog)
 209 {
 210         int err;
 211
 212         if (!prog->offloaded)
 213                 return;
 214
 215         err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
 216         if (err) {
 217                 pr_err("Stopping hardware offload failed: %d\n", err);
 218                 return;
 219         }
 220
 221         prog->offloaded = false;
 222 }
 223
 224 static int cls_bpf_init(struct tcf_proto *tp)
 225 {
 226         struct cls_bpf_head *head;
 227
 228         head = kzalloc(sizeof(*head), GFP_KERNEL);
 229         if (head == NULL)
 230                 return -ENOBUFS;
 231
 232         INIT_LIST_HEAD_RCU(&head->plist);
 233         rcu_assign_pointer(tp->root, head);
 234
 235         return 0;
 236 }
 237
 238 static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 239 {
 240         tcf_exts_destroy(&prog->exts);
 241
 242         if (cls_bpf_is_ebpf(prog))
 243                 bpf_prog_put(prog->filter);
 244         else
 245                 bpf_prog_destroy(prog->filter);
 246
 247         kfree(prog->bpf_name);
 248         kfree(prog->bpf_ops);
 249         kfree(prog);
 250 }
 251
 252 static void __cls_bpf_delete_prog(struct rcu_head *rcu)
 253 {
 254         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 255
 256         cls_bpf_delete_prog(prog->tp, prog);
 257 }
 258
 259 static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
 260 {
 261         struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg;
 262
 263         cls_bpf_stop_offload(tp, prog);
 264         list_del_rcu(&prog->link);
 265         tcf_unbind_filter(tp, &prog->res);
 266         call_rcu(&prog->rcu, __cls_bpf_delete_prog);
 267
 268         return 0;
 269 }
 270
 271 static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
 272 {
 273         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 274         struct cls_bpf_prog *prog, *tmp;
 275
 276         if (!force && !list_empty(&head->plist))
 277                 return false;
 278
 279         list_for_each_entry_safe(prog, tmp, &head->plist, link) {
 280                 cls_bpf_stop_offload(tp, prog);
 281                 list_del_rcu(&prog->link);
 282                 tcf_unbind_filter(tp, &prog->res);
 283                 call_rcu(&prog->rcu, __cls_bpf_delete_prog);
 284         }
 285
 286         RCU_INIT_POINTER(tp->root, NULL);
 287         kfree_rcu(head, rcu);
 288         return true;
 289 }
 290
 291 static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
 292 {
 293         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 294         struct cls_bpf_prog *prog;
 295         unsigned long ret = 0UL;
 296
 297         if (head == NULL)
 298                 return 0UL;
 299
 300         list_for_each_entry(prog, &head->plist, link) {
 301                 if (prog->handle == handle) {
 302                         ret = (unsigned long) prog;
 303                         break;
 304                 }
 305         }
 306
 307         return ret;
 308 }
 309
 310 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 311 {
 312         struct sock_filter *bpf_ops;
 313         struct sock_fprog_kern fprog_tmp;
 314         struct bpf_prog *fp;
 315         u16 bpf_size, bpf_num_ops;
 316         int ret;
 317
 318         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 319         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 320                 return -EINVAL;
 321
 322         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 323         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 324                 return -EINVAL;
 325
 326         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 327         if (bpf_ops == NULL)
 328                 return -ENOMEM;
 329
 330         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 331
 332         fprog_tmp.len = bpf_num_ops;
 333         fprog_tmp.filter = bpf_ops;
 334
 335         ret = bpf_prog_create(&fp, &fprog_tmp);
 336         if (ret < 0) {
 337                 kfree(bpf_ops);
 338                 return ret;
 339         }
 340
 341         prog->bpf_ops = bpf_ops;
 342         prog->bpf_num_ops = bpf_num_ops;
 343         prog->bpf_name = NULL;
 344         prog->filter = fp;
 345
 346         return 0;
 347 }
 348
 349 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 350                                  const struct tcf_proto *tp)
 351 {
 352         struct bpf_prog *fp;
 353         char *name = NULL;
 354         u32 bpf_fd;
 355
 356         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 357
 358         fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
 359         if (IS_ERR(fp))
 360                 return PTR_ERR(fp);
 361
 362         if (tb[TCA_BPF_NAME]) {
 363                 name = kmemdup(nla_data(tb[TCA_BPF_NAME]),
 364                                nla_len(tb[TCA_BPF_NAME]),
 365                                GFP_KERNEL);
 366                 if (!name) {
 367                         bpf_prog_put(fp);
 368                         return -ENOMEM;
 369                 }
 370         }
 371
 372         prog->bpf_ops = NULL;
 373         prog->bpf_fd = bpf_fd;
 374         prog->bpf_name = name;
 375         prog->filter = fp;
 376
 377         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 378                 netif_keep_dst(qdisc_dev(tp->q));
 379
 380         return 0;
 381 }
 382
 383 static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
 384                                    struct cls_bpf_prog *prog,
 385                                    unsigned long base, struct nlattr **tb,
 386                                    struct nlattr *est, bool ovr)
 387 {
 388         bool is_bpf, is_ebpf, have_exts = false;
 389         struct tcf_exts exts;
 390         u32 gen_flags = 0;
 391         int ret;
 392
 393         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 394         is_ebpf = tb[TCA_BPF_FD];
 395         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 396                 return -EINVAL;
 397
 398         ret = tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 399         if (ret < 0)
 400                 return ret;
 401         ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
 402         if (ret < 0)
 403                 goto errout;
 404
 405         if (tb[TCA_BPF_FLAGS]) {
 406                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 407
 408                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
 409                         ret = -EINVAL;
 410                         goto errout;
 411                 }
 412
 413                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 414         }
 415         if (tb[TCA_BPF_FLAGS_GEN]) {
 416                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 417                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 418                     !tc_flags_valid(gen_flags)) {
 419                         ret = -EINVAL;
 420                         goto errout;
 421                 }
 422         }
 423
 424         prog->exts_integrated = have_exts;
 425         prog->gen_flags = gen_flags;
 426
 427         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 428                        cls_bpf_prog_from_efd(tb, prog, tp);
 429         if (ret < 0)
 430                 goto errout;
 431
 432         if (tb[TCA_BPF_CLASSID]) {
 433                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 434                 tcf_bind_filter(tp, &prog->res, base);
 435         }
 436
 437         tcf_exts_change(tp, &prog->exts, &exts);
 438         return 0;
 439
 440 errout:
 441         tcf_exts_destroy(&exts);
 442         return ret;
 443 }
 444
 445 static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
 446                                    struct cls_bpf_head *head)
 447 {
 448         unsigned int i = 0x80000000;
 449         u32 handle;
 450
 451         do {
 452                 if (++head->hgen == 0x7FFFFFFF)
 453                         head->hgen = 1;
 454         } while (--i > 0 && cls_bpf_get(tp, head->hgen));
 455
 456         if (unlikely(i == 0)) {
 457                 pr_err("Insufficient number of handles\n");
 458                 handle = 0;
 459         } else {
 460                 handle = head->hgen;
 461         }
 462
 463         return handle;
 464 }
 465
 466 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 467                           struct tcf_proto *tp, unsigned long base,
 468                           u32 handle, struct nlattr **tca,
 469                           unsigned long *arg, bool ovr)
 470 {
 471         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 472         struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
 473         struct nlattr *tb[TCA_BPF_MAX + 1];
 474         struct cls_bpf_prog *prog;
 475         int ret;
 476
 477         if (tca[TCA_OPTIONS] == NULL)
 478                 return -EINVAL;
 479
 480         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy);
 481         if (ret < 0)
 482                 return ret;
 483
 484         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 485         if (!prog)
 486                 return -ENOBUFS;
 487
 488         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 489         if (ret < 0)
 490                 goto errout;
 491
 492         if (oldprog) {
 493                 if (handle && oldprog->handle != handle) {
 494                         ret = -EINVAL;
 495                         goto errout;
 496                 }
 497         }
 498
 499         if (handle == 0)
 500                 prog->handle = cls_bpf_grab_new_handle(tp, head);
 501         else
 502                 prog->handle = handle;
 503         if (prog->handle == 0) {
 504                 ret = -EINVAL;
 505                 goto errout;
 506         }
 507
 508         ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE],
 509                                       ovr);
 510         if (ret < 0)
 511                 goto errout;
 512
 513         ret = cls_bpf_offload(tp, prog, oldprog);
 514         if (ret) {
 515                 cls_bpf_delete_prog(tp, prog);
 516                 return ret;
 517         }
 518
 519         if (oldprog) {
 520                 list_replace_rcu(&oldprog->link, &prog->link);
 521                 tcf_unbind_filter(tp, &oldprog->res);
 522                 call_rcu(&oldprog->rcu, __cls_bpf_delete_prog);
 523         } else {
 524                 list_add_rcu(&prog->link, &head->plist);
 525         }
 526
 527         *arg = (unsigned long) prog;
 528         return 0;
 529
 530 errout:
 531         tcf_exts_destroy(&prog->exts);
 532         kfree(prog);
 533         return ret;
 534 }
 535
 536 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 537                                  struct sk_buff *skb)
 538 {
 539         struct nlattr *nla;
 540
 541         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 542                 return -EMSGSIZE;
 543
 544         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 545                           sizeof(struct sock_filter));
 546         if (nla == NULL)
 547                 return -EMSGSIZE;
 548
 549         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 550
 551         return 0;
 552 }
 553
 554 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 555                                   struct sk_buff *skb)
 556 {
 557         if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd))
 558                 return -EMSGSIZE;
 559
 560         if (prog->bpf_name &&
 561             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 562                 return -EMSGSIZE;
 563
 564         return 0;
 565 }
 566
 567 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
 568                         struct sk_buff *skb, struct tcmsg *tm)
 569 {
 570         struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
 571         struct nlattr *nest;
 572         u32 bpf_flags = 0;
 573         int ret;
 574
 575         if (prog == NULL)
 576                 return skb->len;
 577
 578         tm->tcm_handle = prog->handle;
 579
 580         nest = nla_nest_start(skb, TCA_OPTIONS);
 581         if (nest == NULL)
 582                 goto nla_put_failure;
 583
 584         if (prog->res.classid &&
 585             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 586                 goto nla_put_failure;
 587
 588         if (cls_bpf_is_ebpf(prog))
 589                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 590         else
 591                 ret = cls_bpf_dump_bpf_info(prog, skb);
 592         if (ret)
 593                 goto nla_put_failure;
 594
 595         if (tcf_exts_dump(skb, &prog->exts) < 0)
 596                 goto nla_put_failure;
 597
 598         if (prog->exts_integrated)
 599                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 600         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 601                 goto nla_put_failure;
 602         if (prog->gen_flags &&
 603             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 604                 goto nla_put_failure;
 605
 606         nla_nest_end(skb, nest);
 607
 608         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 609                 goto nla_put_failure;
 610
 611         return skb->len;
 612
 613 nla_put_failure:
 614         nla_nest_cancel(skb, nest);
 615         return -1;
 616 }
 617
 618 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 619 {
 620         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 621         struct cls_bpf_prog *prog;
 622
 623         list_for_each_entry(prog, &head->plist, link) {
 624                 if (arg->count < arg->skip)
 625                         goto skip;
 626                 if (arg->fn(tp, (unsigned long) prog, arg) < 0) {
 627                         arg->stop = 1;
 628                         break;
 629                 }
 630 skip:
 631                 arg->count++;
 632         }
 633 }
 634
 635 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 636         .kind           =       "bpf",
 637         .owner          =       THIS_MODULE,
 638         .classify       =       cls_bpf_classify,
 639         .init           =       cls_bpf_init,
 640         .destroy        =       cls_bpf_destroy,
 641         .get            =       cls_bpf_get,
 642         .change         =       cls_bpf_change,
 643         .delete         =       cls_bpf_delete,
 644         .walk           =       cls_bpf_walk,
 645         .dump           =       cls_bpf_dump,
 646 };
 647
 648 static int __init cls_bpf_init_mod(void)
 649 {
 650         return register_tcf_proto_ops(&cls_bpf_ops);
 651 }
 652
 653 static void __exit cls_bpf_exit_mod(void)
 654 {
 655         unregister_tcf_proto_ops(&cls_bpf_ops);
 656 }
 657
 658 module_init(cls_bpf_init_mod);
 659 module_exit(cls_bpf_exit_mod);