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         u16 bpf_num_ops;
  49         struct sock_filter *bpf_ops;
  50         const char *bpf_name;
  51         struct tcf_proto *tp;
  52         union {
  53                 struct work_struct work;
  54                 struct rcu_head rcu;
  55         };
  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_TRAP:
  77         case TC_ACT_REDIRECT:
  78         case TC_ACT_UNSPEC:
  79                 return code;
  80         default:
  81                 return TC_ACT_UNSPEC;
  82         }
  83 }
  84
  85 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  86                             struct tcf_result *res)
  87 {
  88         struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
  89         bool at_ingress = skb_at_tc_ingress(skb);
  90         struct cls_bpf_prog *prog;
  91         int ret = -1;
  92
  93         /* Needed here for accessing maps. */
  94         rcu_read_lock();
  95         list_for_each_entry_rcu(prog, &head->plist, link) {
  96                 int filter_res;
  97
  98                 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
  99
 100                 if (tc_skip_sw(prog->gen_flags)) {
 101                         filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
 102                 } else if (at_ingress) {
 103                         /* It is safe to push/pull even if skb_shared() */
 104                         __skb_push(skb, skb->mac_len);
 105                         bpf_compute_data_end(skb);
 106                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 107                         __skb_pull(skb, skb->mac_len);
 108                 } else {
 109                         bpf_compute_data_end(skb);
 110                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 111                 }
 112
 113                 if (prog->exts_integrated) {
 114                         res->class   = 0;
 115                         res->classid = TC_H_MAJ(prog->res.classid) |
 116                                        qdisc_skb_cb(skb)->tc_classid;
 117
 118                         ret = cls_bpf_exec_opcode(filter_res);
 119                         if (ret == TC_ACT_UNSPEC)
 120                                 continue;
 121                         break;
 122                 }
 123
 124                 if (filter_res == 0)
 125                         continue;
 126                 if (filter_res != -1) {
 127                         res->class   = 0;
 128                         res->classid = filter_res;
 129                 } else {
 130                         *res = prog->res;
 131                 }
 132
 133                 ret = tcf_exts_exec(skb, &prog->exts, res);
 134                 if (ret < 0)
 135                         continue;
 136
 137                 break;
 138         }
 139         rcu_read_unlock();
 140
 141         return ret;
 142 }
 143
 144 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
 145 {
 146         return !prog->bpf_ops;
 147 }
 148
 149 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 150                                enum tc_clsbpf_command cmd)
 151 {
 152         struct net_device *dev = tp->q->dev_queue->dev;
 153         struct tc_cls_bpf_offload cls_bpf = {};
 154         int err;
 155
 156         tc_cls_common_offload_init(&cls_bpf.common, tp);
 157         cls_bpf.command = cmd;
 158         cls_bpf.exts = &prog->exts;
 159         cls_bpf.prog = prog->filter;
 160         cls_bpf.name = prog->bpf_name;
 161         cls_bpf.exts_integrated = prog->exts_integrated;
 162         cls_bpf.gen_flags = prog->gen_flags;
 163
 164         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_CLSBPF, &cls_bpf);
 165         if (!err && (cmd == TC_CLSBPF_ADD || cmd == TC_CLSBPF_REPLACE))
 166                 prog->gen_flags |= TCA_CLS_FLAGS_IN_HW;
 167
 168         return err;
 169 }
 170
 171 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 172                            struct cls_bpf_prog *oldprog)
 173 {
 174         struct net_device *dev = tp->q->dev_queue->dev;
 175         struct cls_bpf_prog *obj = prog;
 176         enum tc_clsbpf_command cmd;
 177         bool skip_sw;
 178         int ret;
 179
 180         skip_sw = tc_skip_sw(prog->gen_flags) ||
 181                 (oldprog && tc_skip_sw(oldprog->gen_flags));
 182
 183         if (oldprog && oldprog->offloaded) {
 184                 if (tc_should_offload(dev, prog->gen_flags)) {
 185                         cmd = TC_CLSBPF_REPLACE;
 186                 } else if (!tc_skip_sw(prog->gen_flags)) {
 187                         obj = oldprog;
 188                         cmd = TC_CLSBPF_DESTROY;
 189                 } else {
 190                         return -EINVAL;
 191                 }
 192         } else {
 193                 if (!tc_should_offload(dev, prog->gen_flags))
 194                         return skip_sw ? -EINVAL : 0;
 195                 cmd = TC_CLSBPF_ADD;
 196         }
 197
 198         ret = cls_bpf_offload_cmd(tp, obj, cmd);
 199         if (ret)
 200                 return skip_sw ? ret : 0;
 201
 202         obj->offloaded = true;
 203         if (oldprog)
 204                 oldprog->offloaded = false;
 205
 206         return 0;
 207 }
 208
 209 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 210                                  struct cls_bpf_prog *prog)
 211 {
 212         int err;
 213
 214         if (!prog->offloaded)
 215                 return;
 216
 217         err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
 218         if (err) {
 219                 pr_err("Stopping hardware offload failed: %d\n", err);
 220                 return;
 221         }
 222
 223         prog->offloaded = false;
 224 }
 225
 226 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 227                                          struct cls_bpf_prog *prog)
 228 {
 229         if (!prog->offloaded)
 230                 return;
 231
 232         cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS);
 233 }
 234
 235 static int cls_bpf_init(struct tcf_proto *tp)
 236 {
 237         struct cls_bpf_head *head;
 238
 239         head = kzalloc(sizeof(*head), GFP_KERNEL);
 240         if (head == NULL)
 241                 return -ENOBUFS;
 242
 243         INIT_LIST_HEAD_RCU(&head->plist);
 244         rcu_assign_pointer(tp->root, head);
 245
 246         return 0;
 247 }
 248
 249 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 250 {
 251         tcf_exts_destroy(&prog->exts);
 252         tcf_exts_put_net(&prog->exts);
 253
 254         if (cls_bpf_is_ebpf(prog))
 255                 bpf_prog_put(prog->filter);
 256         else
 257                 bpf_prog_destroy(prog->filter);
 258
 259         kfree(prog->bpf_name);
 260         kfree(prog->bpf_ops);
 261         kfree(prog);
 262 }
 263
 264 static void cls_bpf_delete_prog_work(struct work_struct *work)
 265 {
 266         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 267
 268         rtnl_lock();
 269         __cls_bpf_delete_prog(prog);
 270         rtnl_unlock();
 271 }
 272
 273 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 274 {
 275         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 276
 277         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 278         tcf_queue_work(&prog->work);
 279 }
 280
 281 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 282 {
 283         cls_bpf_stop_offload(tp, prog);
 284         list_del_rcu(&prog->link);
 285         tcf_unbind_filter(tp, &prog->res);
 286         if (tcf_exts_get_net(&prog->exts))
 287                 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 288         else
 289                 __cls_bpf_delete_prog(prog);
 290 }
 291
 292 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last)
 293 {
 294         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 295
 296         __cls_bpf_delete(tp, arg);
 297         *last = list_empty(&head->plist);
 298         return 0;
 299 }
 300
 301 static void cls_bpf_destroy(struct tcf_proto *tp)
 302 {
 303         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 304         struct cls_bpf_prog *prog, *tmp;
 305
 306         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 307                 __cls_bpf_delete(tp, prog);
 308
 309         kfree_rcu(head, rcu);
 310 }
 311
 312 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 313 {
 314         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 315         struct cls_bpf_prog *prog;
 316
 317         list_for_each_entry(prog, &head->plist, link) {
 318                 if (prog->handle == handle)
 319                         return prog;
 320         }
 321
 322         return NULL;
 323 }
 324
 325 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 326 {
 327         struct sock_filter *bpf_ops;
 328         struct sock_fprog_kern fprog_tmp;
 329         struct bpf_prog *fp;
 330         u16 bpf_size, bpf_num_ops;
 331         int ret;
 332
 333         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 334         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 335                 return -EINVAL;
 336
 337         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 338         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 339                 return -EINVAL;
 340
 341         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 342         if (bpf_ops == NULL)
 343                 return -ENOMEM;
 344
 345         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 346
 347         fprog_tmp.len = bpf_num_ops;
 348         fprog_tmp.filter = bpf_ops;
 349
 350         ret = bpf_prog_create(&fp, &fprog_tmp);
 351         if (ret < 0) {
 352                 kfree(bpf_ops);
 353                 return ret;
 354         }
 355
 356         prog->bpf_ops = bpf_ops;
 357         prog->bpf_num_ops = bpf_num_ops;
 358         prog->bpf_name = NULL;
 359         prog->filter = fp;
 360
 361         return 0;
 362 }
 363
 364 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 365                                  const struct tcf_proto *tp)
 366 {
 367         struct bpf_prog *fp;
 368         char *name = NULL;
 369         u32 bpf_fd;
 370
 371         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 372
 373         fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
 374         if (IS_ERR(fp))
 375                 return PTR_ERR(fp);
 376
 377         if (tb[TCA_BPF_NAME]) {
 378                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 379                 if (!name) {
 380                         bpf_prog_put(fp);
 381                         return -ENOMEM;
 382                 }
 383         }
 384
 385         prog->bpf_ops = NULL;
 386         prog->bpf_name = name;
 387         prog->filter = fp;
 388
 389         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 390                 netif_keep_dst(qdisc_dev(tp->q));
 391
 392         return 0;
 393 }
 394
 395 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 396                              struct cls_bpf_prog *prog, unsigned long base,
 397                              struct nlattr **tb, struct nlattr *est, bool ovr)
 398 {
 399         bool is_bpf, is_ebpf, have_exts = false;
 400         u32 gen_flags = 0;
 401         int ret;
 402
 403         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 404         is_ebpf = tb[TCA_BPF_FD];
 405         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 406                 return -EINVAL;
 407
 408         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr);
 409         if (ret < 0)
 410                 return ret;
 411
 412         if (tb[TCA_BPF_FLAGS]) {
 413                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 414
 415                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 416                         return -EINVAL;
 417
 418                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 419         }
 420         if (tb[TCA_BPF_FLAGS_GEN]) {
 421                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 422                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 423                     !tc_flags_valid(gen_flags))
 424                         return -EINVAL;
 425         }
 426
 427         prog->exts_integrated = have_exts;
 428         prog->gen_flags = gen_flags;
 429
 430         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 431                        cls_bpf_prog_from_efd(tb, prog, tp);
 432         if (ret < 0)
 433                 return ret;
 434
 435         if (tb[TCA_BPF_CLASSID]) {
 436                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 437                 tcf_bind_filter(tp, &prog->res, base);
 438         }
 439
 440         return 0;
 441 }
 442
 443 static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
 444                                    struct cls_bpf_head *head)
 445 {
 446         unsigned int i = 0x80000000;
 447         u32 handle;
 448
 449         do {
 450                 if (++head->hgen == 0x7FFFFFFF)
 451                         head->hgen = 1;
 452         } while (--i > 0 && cls_bpf_get(tp, head->hgen));
 453
 454         if (unlikely(i == 0)) {
 455                 pr_err("Insufficient number of handles\n");
 456                 handle = 0;
 457         } else {
 458                 handle = head->hgen;
 459         }
 460
 461         return handle;
 462 }
 463
 464 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 465                           struct tcf_proto *tp, unsigned long base,
 466                           u32 handle, struct nlattr **tca,
 467                           void **arg, bool ovr)
 468 {
 469         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 470         struct cls_bpf_prog *oldprog = *arg;
 471         struct nlattr *tb[TCA_BPF_MAX + 1];
 472         struct cls_bpf_prog *prog;
 473         int ret;
 474
 475         if (tca[TCA_OPTIONS] == NULL)
 476                 return -EINVAL;
 477
 478         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 479                                NULL);
 480         if (ret < 0)
 481                 return ret;
 482
 483         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 484         if (!prog)
 485                 return -ENOBUFS;
 486
 487         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 488         if (ret < 0)
 489                 goto errout;
 490
 491         if (oldprog) {
 492                 if (handle && oldprog->handle != handle) {
 493                         ret = -EINVAL;
 494                         goto errout;
 495                 }
 496         }
 497
 498         if (handle == 0)
 499                 prog->handle = cls_bpf_grab_new_handle(tp, head);
 500         else
 501                 prog->handle = handle;
 502         if (prog->handle == 0) {
 503                 ret = -EINVAL;
 504                 goto errout;
 505         }
 506
 507         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
 508         if (ret < 0)
 509                 goto errout;
 510
 511         ret = cls_bpf_offload(tp, prog, oldprog);
 512         if (ret) {
 513                 __cls_bpf_delete_prog(prog);
 514                 return ret;
 515         }
 516
 517         if (!tc_in_hw(prog->gen_flags))
 518                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 519
 520         if (oldprog) {
 521                 list_replace_rcu(&oldprog->link, &prog->link);
 522                 tcf_unbind_filter(tp, &oldprog->res);
 523                 tcf_exts_get_net(&oldprog->exts);
 524                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 525         } else {
 526                 list_add_rcu(&prog->link, &head->plist);
 527         }
 528
 529         *arg = prog;
 530         return 0;
 531
 532 errout:
 533         tcf_exts_destroy(&prog->exts);
 534         kfree(prog);
 535         return ret;
 536 }
 537
 538 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 539                                  struct sk_buff *skb)
 540 {
 541         struct nlattr *nla;
 542
 543         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 544                 return -EMSGSIZE;
 545
 546         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 547                           sizeof(struct sock_filter));
 548         if (nla == NULL)
 549                 return -EMSGSIZE;
 550
 551         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 552
 553         return 0;
 554 }
 555
 556 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 557                                   struct sk_buff *skb)
 558 {
 559         struct nlattr *nla;
 560
 561         if (prog->bpf_name &&
 562             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 563                 return -EMSGSIZE;
 564
 565         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 566                 return -EMSGSIZE;
 567
 568         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 569         if (nla == NULL)
 570                 return -EMSGSIZE;
 571
 572         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 573
 574         return 0;
 575 }
 576
 577 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 578                         struct sk_buff *skb, struct tcmsg *tm)
 579 {
 580         struct cls_bpf_prog *prog = fh;
 581         struct nlattr *nest;
 582         u32 bpf_flags = 0;
 583         int ret;
 584
 585         if (prog == NULL)
 586                 return skb->len;
 587
 588         tm->tcm_handle = prog->handle;
 589
 590         cls_bpf_offload_update_stats(tp, prog);
 591
 592         nest = nla_nest_start(skb, TCA_OPTIONS);
 593         if (nest == NULL)
 594                 goto nla_put_failure;
 595
 596         if (prog->res.classid &&
 597             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 598                 goto nla_put_failure;
 599
 600         if (cls_bpf_is_ebpf(prog))
 601                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 602         else
 603                 ret = cls_bpf_dump_bpf_info(prog, skb);
 604         if (ret)
 605                 goto nla_put_failure;
 606
 607         if (tcf_exts_dump(skb, &prog->exts) < 0)
 608                 goto nla_put_failure;
 609
 610         if (prog->exts_integrated)
 611                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 612         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 613                 goto nla_put_failure;
 614         if (prog->gen_flags &&
 615             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 616                 goto nla_put_failure;
 617
 618         nla_nest_end(skb, nest);
 619
 620         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 621                 goto nla_put_failure;
 622
 623         return skb->len;
 624
 625 nla_put_failure:
 626         nla_nest_cancel(skb, nest);
 627         return -1;
 628 }
 629
 630 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 631 {
 632         struct cls_bpf_prog *prog = fh;
 633
 634         if (prog && prog->res.classid == classid)
 635                 prog->res.class = cl;
 636 }
 637
 638 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 639 {
 640         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 641         struct cls_bpf_prog *prog;
 642
 643         list_for_each_entry(prog, &head->plist, link) {
 644                 if (arg->count < arg->skip)
 645                         goto skip;
 646                 if (arg->fn(tp, prog, arg) < 0) {
 647                         arg->stop = 1;
 648                         break;
 649                 }
 650 skip:
 651                 arg->count++;
 652         }
 653 }
 654
 655 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 656         .kind           =       "bpf",
 657         .owner          =       THIS_MODULE,
 658         .classify       =       cls_bpf_classify,
 659         .init           =       cls_bpf_init,
 660         .destroy        =       cls_bpf_destroy,
 661         .get            =       cls_bpf_get,
 662         .change         =       cls_bpf_change,
 663         .delete         =       cls_bpf_delete,
 664         .walk           =       cls_bpf_walk,
 665         .dump           =       cls_bpf_dump,
 666         .bind_class     =       cls_bpf_bind_class,
 667 };
 668
 669 static int __init cls_bpf_init_mod(void)
 670 {
 671         return register_tcf_proto_ops(&cls_bpf_ops);
 672 }
 673
 674 static void __exit cls_bpf_exit_mod(void)
 675 {
 676         unregister_tcf_proto_ops(&cls_bpf_ops);
 677 }
 678
 679 module_init(cls_bpf_init_mod);
 680 module_exit(cls_bpf_exit_mod);