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_free_parms(struct cls_bpf_prog *prog)
 250 {
 251         if (cls_bpf_is_ebpf(prog))
 252                 bpf_prog_put(prog->filter);
 253         else
 254                 bpf_prog_destroy(prog->filter);
 255
 256         kfree(prog->bpf_name);
 257         kfree(prog->bpf_ops);
 258 }
 259
 260 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 261 {
 262         tcf_exts_destroy(&prog->exts);
 263         tcf_exts_put_net(&prog->exts);
 264
 265         cls_bpf_free_parms(prog);
 266         kfree(prog);
 267 }
 268
 269 static void cls_bpf_delete_prog_work(struct work_struct *work)
 270 {
 271         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 272
 273         rtnl_lock();
 274         __cls_bpf_delete_prog(prog);
 275         rtnl_unlock();
 276 }
 277
 278 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 279 {
 280         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 281
 282         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 283         tcf_queue_work(&prog->work);
 284 }
 285
 286 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 287 {
 288         cls_bpf_stop_offload(tp, prog);
 289         list_del_rcu(&prog->link);
 290         tcf_unbind_filter(tp, &prog->res);
 291         if (tcf_exts_get_net(&prog->exts))
 292                 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 293         else
 294                 __cls_bpf_delete_prog(prog);
 295 }
 296
 297 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last)
 298 {
 299         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 300
 301         __cls_bpf_delete(tp, arg);
 302         *last = list_empty(&head->plist);
 303         return 0;
 304 }
 305
 306 static void cls_bpf_destroy(struct tcf_proto *tp)
 307 {
 308         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 309         struct cls_bpf_prog *prog, *tmp;
 310
 311         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 312                 __cls_bpf_delete(tp, prog);
 313
 314         kfree_rcu(head, rcu);
 315 }
 316
 317 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 318 {
 319         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 320         struct cls_bpf_prog *prog;
 321
 322         list_for_each_entry(prog, &head->plist, link) {
 323                 if (prog->handle == handle)
 324                         return prog;
 325         }
 326
 327         return NULL;
 328 }
 329
 330 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 331 {
 332         struct sock_filter *bpf_ops;
 333         struct sock_fprog_kern fprog_tmp;
 334         struct bpf_prog *fp;
 335         u16 bpf_size, bpf_num_ops;
 336         int ret;
 337
 338         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 339         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 340                 return -EINVAL;
 341
 342         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 343         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 344                 return -EINVAL;
 345
 346         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 347         if (bpf_ops == NULL)
 348                 return -ENOMEM;
 349
 350         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 351
 352         fprog_tmp.len = bpf_num_ops;
 353         fprog_tmp.filter = bpf_ops;
 354
 355         ret = bpf_prog_create(&fp, &fprog_tmp);
 356         if (ret < 0) {
 357                 kfree(bpf_ops);
 358                 return ret;
 359         }
 360
 361         prog->bpf_ops = bpf_ops;
 362         prog->bpf_num_ops = bpf_num_ops;
 363         prog->bpf_name = NULL;
 364         prog->filter = fp;
 365
 366         return 0;
 367 }
 368
 369 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 370                                  const struct tcf_proto *tp)
 371 {
 372         struct bpf_prog *fp;
 373         char *name = NULL;
 374         u32 bpf_fd;
 375
 376         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 377
 378         fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
 379         if (IS_ERR(fp))
 380                 return PTR_ERR(fp);
 381
 382         if (tb[TCA_BPF_NAME]) {
 383                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 384                 if (!name) {
 385                         bpf_prog_put(fp);
 386                         return -ENOMEM;
 387                 }
 388         }
 389
 390         prog->bpf_ops = NULL;
 391         prog->bpf_name = name;
 392         prog->filter = fp;
 393
 394         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 395                 netif_keep_dst(qdisc_dev(tp->q));
 396
 397         return 0;
 398 }
 399
 400 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 401                              struct cls_bpf_prog *prog, unsigned long base,
 402                              struct nlattr **tb, struct nlattr *est, bool ovr)
 403 {
 404         bool is_bpf, is_ebpf, have_exts = false;
 405         u32 gen_flags = 0;
 406         int ret;
 407
 408         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 409         is_ebpf = tb[TCA_BPF_FD];
 410         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 411                 return -EINVAL;
 412
 413         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr);
 414         if (ret < 0)
 415                 return ret;
 416
 417         if (tb[TCA_BPF_FLAGS]) {
 418                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 419
 420                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 421                         return -EINVAL;
 422
 423                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 424         }
 425         if (tb[TCA_BPF_FLAGS_GEN]) {
 426                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 427                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 428                     !tc_flags_valid(gen_flags))
 429                         return -EINVAL;
 430         }
 431
 432         prog->exts_integrated = have_exts;
 433         prog->gen_flags = gen_flags;
 434
 435         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 436                        cls_bpf_prog_from_efd(tb, prog, tp);
 437         if (ret < 0)
 438                 return ret;
 439
 440         if (tb[TCA_BPF_CLASSID]) {
 441                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 442                 tcf_bind_filter(tp, &prog->res, base);
 443         }
 444
 445         return 0;
 446 }
 447
 448 static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
 449                                    struct cls_bpf_head *head)
 450 {
 451         unsigned int i = 0x80000000;
 452         u32 handle;
 453
 454         do {
 455                 if (++head->hgen == 0x7FFFFFFF)
 456                         head->hgen = 1;
 457         } while (--i > 0 && cls_bpf_get(tp, head->hgen));
 458
 459         if (unlikely(i == 0)) {
 460                 pr_err("Insufficient number of handles\n");
 461                 handle = 0;
 462         } else {
 463                 handle = head->hgen;
 464         }
 465
 466         return handle;
 467 }
 468
 469 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 470                           struct tcf_proto *tp, unsigned long base,
 471                           u32 handle, struct nlattr **tca,
 472                           void **arg, bool ovr)
 473 {
 474         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 475         struct cls_bpf_prog *oldprog = *arg;
 476         struct nlattr *tb[TCA_BPF_MAX + 1];
 477         struct cls_bpf_prog *prog;
 478         int ret;
 479
 480         if (tca[TCA_OPTIONS] == NULL)
 481                 return -EINVAL;
 482
 483         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 484                                NULL);
 485         if (ret < 0)
 486                 return ret;
 487
 488         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 489         if (!prog)
 490                 return -ENOBUFS;
 491
 492         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 493         if (ret < 0)
 494                 goto errout;
 495
 496         if (oldprog) {
 497                 if (handle && oldprog->handle != handle) {
 498                         ret = -EINVAL;
 499                         goto errout;
 500                 }
 501         }
 502
 503         if (handle == 0)
 504                 prog->handle = cls_bpf_grab_new_handle(tp, head);
 505         else
 506                 prog->handle = handle;
 507         if (prog->handle == 0) {
 508                 ret = -EINVAL;
 509                 goto errout;
 510         }
 511
 512         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
 513         if (ret < 0)
 514                 goto errout;
 515
 516         ret = cls_bpf_offload(tp, prog, oldprog);
 517         if (ret)
 518                 goto errout_parms;
 519
 520         if (!tc_in_hw(prog->gen_flags))
 521                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 522
 523         if (oldprog) {
 524                 list_replace_rcu(&oldprog->link, &prog->link);
 525                 tcf_unbind_filter(tp, &oldprog->res);
 526                 tcf_exts_get_net(&oldprog->exts);
 527                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 528         } else {
 529                 list_add_rcu(&prog->link, &head->plist);
 530         }
 531
 532         *arg = prog;
 533         return 0;
 534
 535 errout_parms:
 536         cls_bpf_free_parms(prog);
 537 errout:
 538         tcf_exts_destroy(&prog->exts);
 539         kfree(prog);
 540         return ret;
 541 }
 542
 543 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 544                                  struct sk_buff *skb)
 545 {
 546         struct nlattr *nla;
 547
 548         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 549                 return -EMSGSIZE;
 550
 551         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 552                           sizeof(struct sock_filter));
 553         if (nla == NULL)
 554                 return -EMSGSIZE;
 555
 556         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 557
 558         return 0;
 559 }
 560
 561 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 562                                   struct sk_buff *skb)
 563 {
 564         struct nlattr *nla;
 565
 566         if (prog->bpf_name &&
 567             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 568                 return -EMSGSIZE;
 569
 570         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 571                 return -EMSGSIZE;
 572
 573         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 574         if (nla == NULL)
 575                 return -EMSGSIZE;
 576
 577         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 578
 579         return 0;
 580 }
 581
 582 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 583                         struct sk_buff *skb, struct tcmsg *tm)
 584 {
 585         struct cls_bpf_prog *prog = fh;
 586         struct nlattr *nest;
 587         u32 bpf_flags = 0;
 588         int ret;
 589
 590         if (prog == NULL)
 591                 return skb->len;
 592
 593         tm->tcm_handle = prog->handle;
 594
 595         cls_bpf_offload_update_stats(tp, prog);
 596
 597         nest = nla_nest_start(skb, TCA_OPTIONS);
 598         if (nest == NULL)
 599                 goto nla_put_failure;
 600
 601         if (prog->res.classid &&
 602             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 603                 goto nla_put_failure;
 604
 605         if (cls_bpf_is_ebpf(prog))
 606                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 607         else
 608                 ret = cls_bpf_dump_bpf_info(prog, skb);
 609         if (ret)
 610                 goto nla_put_failure;
 611
 612         if (tcf_exts_dump(skb, &prog->exts) < 0)
 613                 goto nla_put_failure;
 614
 615         if (prog->exts_integrated)
 616                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 617         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 618                 goto nla_put_failure;
 619         if (prog->gen_flags &&
 620             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 621                 goto nla_put_failure;
 622
 623         nla_nest_end(skb, nest);
 624
 625         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 626                 goto nla_put_failure;
 627
 628         return skb->len;
 629
 630 nla_put_failure:
 631         nla_nest_cancel(skb, nest);
 632         return -1;
 633 }
 634
 635 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 636 {
 637         struct cls_bpf_prog *prog = fh;
 638
 639         if (prog && prog->res.classid == classid)
 640                 prog->res.class = cl;
 641 }
 642
 643 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 644 {
 645         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 646         struct cls_bpf_prog *prog;
 647
 648         list_for_each_entry(prog, &head->plist, link) {
 649                 if (arg->count < arg->skip)
 650                         goto skip;
 651                 if (arg->fn(tp, prog, arg) < 0) {
 652                         arg->stop = 1;
 653                         break;
 654                 }
 655 skip:
 656                 arg->count++;
 657         }
 658 }
 659
 660 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 661         .kind           =       "bpf",
 662         .owner          =       THIS_MODULE,
 663         .classify       =       cls_bpf_classify,
 664         .init           =       cls_bpf_init,
 665         .destroy        =       cls_bpf_destroy,
 666         .get            =       cls_bpf_get,
 667         .change         =       cls_bpf_change,
 668         .delete         =       cls_bpf_delete,
 669         .walk           =       cls_bpf_walk,
 670         .dump           =       cls_bpf_dump,
 671         .bind_class     =       cls_bpf_bind_class,
 672 };
 673
 674 static int __init cls_bpf_init_mod(void)
 675 {
 676         return register_tcf_proto_ops(&cls_bpf_ops);
 677 }
 678
 679 static void __exit cls_bpf_exit_mod(void)
 680 {
 681         unregister_tcf_proto_ops(&cls_bpf_ops);
 682 }
 683
 684 module_init(cls_bpf_init_mod);
 685 module_exit(cls_bpf_exit_mod);