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 #include <linux/idr.h>
  21
  22 #include <net/rtnetlink.h>
  23 #include <net/pkt_cls.h>
  24 #include <net/sock.h>
  25
  26 MODULE_LICENSE("GPL");
  27 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
  28 MODULE_DESCRIPTION("TC BPF based classifier");
  29
  30 #define CLS_BPF_NAME_LEN        256
  31 #define CLS_BPF_SUPPORTED_GEN_FLAGS             \
  32         (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
  33
  34 struct cls_bpf_head {
  35         struct list_head plist;
  36         struct idr handle_idr;
  37         struct rcu_head rcu;
  38 };
  39
  40 struct cls_bpf_prog {
  41         struct bpf_prog *filter;
  42         struct list_head link;
  43         struct tcf_result res;
  44         bool exts_integrated;
  45         bool offloaded;
  46         u32 gen_flags;
  47         struct tcf_exts exts;
  48         u32 handle;
  49         u16 bpf_num_ops;
  50         struct sock_filter *bpf_ops;
  51         const char *bpf_name;
  52         struct tcf_proto *tp;
  53         union {
  54                 struct work_struct work;
  55                 struct rcu_head rcu;
  56         };
  57 };
  58
  59 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
  60         [TCA_BPF_CLASSID]       = { .type = NLA_U32 },
  61         [TCA_BPF_FLAGS]         = { .type = NLA_U32 },
  62         [TCA_BPF_FLAGS_GEN]     = { .type = NLA_U32 },
  63         [TCA_BPF_FD]            = { .type = NLA_U32 },
  64         [TCA_BPF_NAME]          = { .type = NLA_NUL_STRING,
  65                                     .len = CLS_BPF_NAME_LEN },
  66         [TCA_BPF_OPS_LEN]       = { .type = NLA_U16 },
  67         [TCA_BPF_OPS]           = { .type = NLA_BINARY,
  68                                     .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
  69 };
  70
  71 static int cls_bpf_exec_opcode(int code)
  72 {
  73         switch (code) {
  74         case TC_ACT_OK:
  75         case TC_ACT_SHOT:
  76         case TC_ACT_STOLEN:
  77         case TC_ACT_TRAP:
  78         case TC_ACT_REDIRECT:
  79         case TC_ACT_UNSPEC:
  80                 return code;
  81         default:
  82                 return TC_ACT_UNSPEC;
  83         }
  84 }
  85
  86 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
  87                             struct tcf_result *res)
  88 {
  89         struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
  90         bool at_ingress = skb_at_tc_ingress(skb);
  91         struct cls_bpf_prog *prog;
  92         int ret = -1;
  93
  94         /* Needed here for accessing maps. */
  95         rcu_read_lock();
  96         list_for_each_entry_rcu(prog, &head->plist, link) {
  97                 int filter_res;
  98
  99                 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
 100
 101                 if (tc_skip_sw(prog->gen_flags)) {
 102                         filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
 103                 } else if (at_ingress) {
 104                         /* It is safe to push/pull even if skb_shared() */
 105                         __skb_push(skb, skb->mac_len);
 106                         bpf_compute_data_pointers(skb);
 107                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 108                         __skb_pull(skb, skb->mac_len);
 109                 } else {
 110                         bpf_compute_data_pointers(skb);
 111                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 112                 }
 113
 114                 if (prog->exts_integrated) {
 115                         res->class   = 0;
 116                         res->classid = TC_H_MAJ(prog->res.classid) |
 117                                        qdisc_skb_cb(skb)->tc_classid;
 118
 119                         ret = cls_bpf_exec_opcode(filter_res);
 120                         if (ret == TC_ACT_UNSPEC)
 121                                 continue;
 122                         break;
 123                 }
 124
 125                 if (filter_res == 0)
 126                         continue;
 127                 if (filter_res != -1) {
 128                         res->class   = 0;
 129                         res->classid = filter_res;
 130                 } else {
 131                         *res = prog->res;
 132                 }
 133
 134                 ret = tcf_exts_exec(skb, &prog->exts, res);
 135                 if (ret < 0)
 136                         continue;
 137
 138                 break;
 139         }
 140         rcu_read_unlock();
 141
 142         return ret;
 143 }
 144
 145 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
 146 {
 147         return !prog->bpf_ops;
 148 }
 149
 150 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 151                                enum tc_clsbpf_command cmd)
 152 {
 153         bool addorrep = cmd == TC_CLSBPF_ADD || cmd == TC_CLSBPF_REPLACE;
 154         struct tcf_block *block = tp->chain->block;
 155         bool skip_sw = tc_skip_sw(prog->gen_flags);
 156         struct tc_cls_bpf_offload cls_bpf = {};
 157         int err;
 158
 159         tc_cls_common_offload_init(&cls_bpf.common, tp);
 160         cls_bpf.command = cmd;
 161         cls_bpf.exts = &prog->exts;
 162         cls_bpf.prog = prog->filter;
 163         cls_bpf.name = prog->bpf_name;
 164         cls_bpf.exts_integrated = prog->exts_integrated;
 165         cls_bpf.gen_flags = prog->gen_flags;
 166
 167         err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
 168         if (addorrep) {
 169                 if (err < 0) {
 170                         cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
 171                         return err;
 172                 } else if (err > 0) {
 173                         prog->gen_flags |= TCA_CLS_FLAGS_IN_HW;
 174                 }
 175         }
 176
 177         if (addorrep && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
 178                 return -EINVAL;
 179
 180         return 0;
 181 }
 182
 183 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 184                            struct cls_bpf_prog *oldprog)
 185 {
 186         struct cls_bpf_prog *obj = prog;
 187         enum tc_clsbpf_command cmd;
 188         bool skip_sw;
 189         int ret;
 190
 191         skip_sw = tc_skip_sw(prog->gen_flags) ||
 192                 (oldprog && tc_skip_sw(oldprog->gen_flags));
 193
 194         if (oldprog && oldprog->offloaded) {
 195                 if (!tc_skip_hw(prog->gen_flags)) {
 196                         cmd = TC_CLSBPF_REPLACE;
 197                 } else if (!tc_skip_sw(prog->gen_flags)) {
 198                         obj = oldprog;
 199                         cmd = TC_CLSBPF_DESTROY;
 200                 } else {
 201                         return -EINVAL;
 202                 }
 203         } else {
 204                 if (tc_skip_hw(prog->gen_flags))
 205                         return skip_sw ? -EINVAL : 0;
 206                 cmd = TC_CLSBPF_ADD;
 207         }
 208
 209         ret = cls_bpf_offload_cmd(tp, obj, cmd);
 210         if (ret)
 211                 return ret;
 212
 213         obj->offloaded = true;
 214         if (oldprog)
 215                 oldprog->offloaded = false;
 216
 217         return 0;
 218 }
 219
 220 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 221                                  struct cls_bpf_prog *prog)
 222 {
 223         int err;
 224
 225         if (!prog->offloaded)
 226                 return;
 227
 228         err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
 229         if (err) {
 230                 pr_err("Stopping hardware offload failed: %d\n", err);
 231                 return;
 232         }
 233
 234         prog->offloaded = false;
 235 }
 236
 237 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 238                                          struct cls_bpf_prog *prog)
 239 {
 240         if (!prog->offloaded)
 241                 return;
 242
 243         cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS);
 244 }
 245
 246 static int cls_bpf_init(struct tcf_proto *tp)
 247 {
 248         struct cls_bpf_head *head;
 249
 250         head = kzalloc(sizeof(*head), GFP_KERNEL);
 251         if (head == NULL)
 252                 return -ENOBUFS;
 253
 254         INIT_LIST_HEAD_RCU(&head->plist);
 255         idr_init(&head->handle_idr);
 256         rcu_assign_pointer(tp->root, head);
 257
 258         return 0;
 259 }
 260
 261 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 262 {
 263         tcf_exts_destroy(&prog->exts);
 264
 265         if (cls_bpf_is_ebpf(prog))
 266                 bpf_prog_put(prog->filter);
 267         else
 268                 bpf_prog_destroy(prog->filter);
 269
 270         kfree(prog->bpf_name);
 271         kfree(prog->bpf_ops);
 272         kfree(prog);
 273 }
 274
 275 static void cls_bpf_delete_prog_work(struct work_struct *work)
 276 {
 277         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 278
 279         rtnl_lock();
 280         __cls_bpf_delete_prog(prog);
 281         rtnl_unlock();
 282 }
 283
 284 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 285 {
 286         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 287
 288         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 289         tcf_queue_work(&prog->work);
 290 }
 291
 292 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 293 {
 294         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 295
 296         idr_remove_ext(&head->handle_idr, prog->handle);
 297         cls_bpf_stop_offload(tp, prog);
 298         list_del_rcu(&prog->link);
 299         tcf_unbind_filter(tp, &prog->res);
 300         call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 301 }
 302
 303 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last)
 304 {
 305         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 306
 307         __cls_bpf_delete(tp, arg);
 308         *last = list_empty(&head->plist);
 309         return 0;
 310 }
 311
 312 static void cls_bpf_destroy(struct tcf_proto *tp)
 313 {
 314         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 315         struct cls_bpf_prog *prog, *tmp;
 316
 317         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 318                 __cls_bpf_delete(tp, prog);
 319
 320         idr_destroy(&head->handle_idr);
 321         kfree_rcu(head, rcu);
 322 }
 323
 324 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 325 {
 326         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 327         struct cls_bpf_prog *prog;
 328
 329         list_for_each_entry(prog, &head->plist, link) {
 330                 if (prog->handle == handle)
 331                         return prog;
 332         }
 333
 334         return NULL;
 335 }
 336
 337 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 338 {
 339         struct sock_filter *bpf_ops;
 340         struct sock_fprog_kern fprog_tmp;
 341         struct bpf_prog *fp;
 342         u16 bpf_size, bpf_num_ops;
 343         int ret;
 344
 345         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 346         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 347                 return -EINVAL;
 348
 349         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 350         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 351                 return -EINVAL;
 352
 353         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 354         if (bpf_ops == NULL)
 355                 return -ENOMEM;
 356
 357         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 358
 359         fprog_tmp.len = bpf_num_ops;
 360         fprog_tmp.filter = bpf_ops;
 361
 362         ret = bpf_prog_create(&fp, &fprog_tmp);
 363         if (ret < 0) {
 364                 kfree(bpf_ops);
 365                 return ret;
 366         }
 367
 368         prog->bpf_ops = bpf_ops;
 369         prog->bpf_num_ops = bpf_num_ops;
 370         prog->bpf_name = NULL;
 371         prog->filter = fp;
 372
 373         return 0;
 374 }
 375
 376 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 377                                  const struct tcf_proto *tp)
 378 {
 379         struct bpf_prog *fp;
 380         char *name = NULL;
 381         u32 bpf_fd;
 382
 383         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 384
 385         fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
 386         if (IS_ERR(fp))
 387                 return PTR_ERR(fp);
 388
 389         if (tb[TCA_BPF_NAME]) {
 390                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 391                 if (!name) {
 392                         bpf_prog_put(fp);
 393                         return -ENOMEM;
 394                 }
 395         }
 396
 397         prog->bpf_ops = NULL;
 398         prog->bpf_name = name;
 399         prog->filter = fp;
 400
 401         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 402                 netif_keep_dst(qdisc_dev(tp->q));
 403
 404         return 0;
 405 }
 406
 407 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 408                              struct cls_bpf_prog *prog, unsigned long base,
 409                              struct nlattr **tb, struct nlattr *est, bool ovr)
 410 {
 411         bool is_bpf, is_ebpf, have_exts = false;
 412         u32 gen_flags = 0;
 413         int ret;
 414
 415         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 416         is_ebpf = tb[TCA_BPF_FD];
 417         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 418                 return -EINVAL;
 419
 420         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr);
 421         if (ret < 0)
 422                 return ret;
 423
 424         if (tb[TCA_BPF_FLAGS]) {
 425                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 426
 427                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 428                         return -EINVAL;
 429
 430                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 431         }
 432         if (tb[TCA_BPF_FLAGS_GEN]) {
 433                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 434                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 435                     !tc_flags_valid(gen_flags))
 436                         return -EINVAL;
 437         }
 438
 439         prog->exts_integrated = have_exts;
 440         prog->gen_flags = gen_flags;
 441
 442         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 443                        cls_bpf_prog_from_efd(tb, prog, tp);
 444         if (ret < 0)
 445                 return ret;
 446
 447         if (tb[TCA_BPF_CLASSID]) {
 448                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 449                 tcf_bind_filter(tp, &prog->res, base);
 450         }
 451
 452         return 0;
 453 }
 454
 455 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 456                           struct tcf_proto *tp, unsigned long base,
 457                           u32 handle, struct nlattr **tca,
 458                           void **arg, bool ovr)
 459 {
 460         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 461         struct cls_bpf_prog *oldprog = *arg;
 462         struct nlattr *tb[TCA_BPF_MAX + 1];
 463         struct cls_bpf_prog *prog;
 464         unsigned long idr_index;
 465         int ret;
 466
 467         if (tca[TCA_OPTIONS] == NULL)
 468                 return -EINVAL;
 469
 470         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 471                                NULL);
 472         if (ret < 0)
 473                 return ret;
 474
 475         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 476         if (!prog)
 477                 return -ENOBUFS;
 478
 479         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 480         if (ret < 0)
 481                 goto errout;
 482
 483         if (oldprog) {
 484                 if (handle && oldprog->handle != handle) {
 485                         ret = -EINVAL;
 486                         goto errout;
 487                 }
 488         }
 489
 490         if (handle == 0) {
 491                 ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 492                                     1, 0x7FFFFFFF, GFP_KERNEL);
 493                 if (ret)
 494                         goto errout;
 495                 prog->handle = idr_index;
 496         } else {
 497                 if (!oldprog) {
 498                         ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 499                                             handle, handle + 1, GFP_KERNEL);
 500                         if (ret)
 501                                 goto errout;
 502                 }
 503                 prog->handle = handle;
 504         }
 505
 506         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
 507         if (ret < 0)
 508                 goto errout_idr;
 509
 510         ret = cls_bpf_offload(tp, prog, oldprog);
 511         if (ret) {
 512                 if (!oldprog)
 513                         idr_remove_ext(&head->handle_idr, prog->handle);
 514                 __cls_bpf_delete_prog(prog);
 515                 return ret;
 516         }
 517
 518         if (!tc_in_hw(prog->gen_flags))
 519                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 520
 521         if (oldprog) {
 522                 idr_replace_ext(&head->handle_idr, prog, handle);
 523                 list_replace_rcu(&oldprog->link, &prog->link);
 524                 tcf_unbind_filter(tp, &oldprog->res);
 525                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 526         } else {
 527                 list_add_rcu(&prog->link, &head->plist);
 528         }
 529
 530         *arg = prog;
 531         return 0;
 532
 533 errout_idr:
 534         if (!oldprog)
 535                 idr_remove_ext(&head->handle_idr, prog->handle);
 536 errout:
 537         tcf_exts_destroy(&prog->exts);
 538         kfree(prog);
 539         return ret;
 540 }
 541
 542 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 543                                  struct sk_buff *skb)
 544 {
 545         struct nlattr *nla;
 546
 547         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 548                 return -EMSGSIZE;
 549
 550         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 551                           sizeof(struct sock_filter));
 552         if (nla == NULL)
 553                 return -EMSGSIZE;
 554
 555         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 556
 557         return 0;
 558 }
 559
 560 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 561                                   struct sk_buff *skb)
 562 {
 563         struct nlattr *nla;
 564
 565         if (prog->bpf_name &&
 566             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 567                 return -EMSGSIZE;
 568
 569         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 570                 return -EMSGSIZE;
 571
 572         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 573         if (nla == NULL)
 574                 return -EMSGSIZE;
 575
 576         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 577
 578         return 0;
 579 }
 580
 581 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 582                         struct sk_buff *skb, struct tcmsg *tm)
 583 {
 584         struct cls_bpf_prog *prog = fh;
 585         struct nlattr *nest;
 586         u32 bpf_flags = 0;
 587         int ret;
 588
 589         if (prog == NULL)
 590                 return skb->len;
 591
 592         tm->tcm_handle = prog->handle;
 593
 594         cls_bpf_offload_update_stats(tp, prog);
 595
 596         nest = nla_nest_start(skb, TCA_OPTIONS);
 597         if (nest == NULL)
 598                 goto nla_put_failure;
 599
 600         if (prog->res.classid &&
 601             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 602                 goto nla_put_failure;
 603
 604         if (cls_bpf_is_ebpf(prog))
 605                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 606         else
 607                 ret = cls_bpf_dump_bpf_info(prog, skb);
 608         if (ret)
 609                 goto nla_put_failure;
 610
 611         if (tcf_exts_dump(skb, &prog->exts) < 0)
 612                 goto nla_put_failure;
 613
 614         if (prog->exts_integrated)
 615                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 616         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 617                 goto nla_put_failure;
 618         if (prog->gen_flags &&
 619             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 620                 goto nla_put_failure;
 621
 622         nla_nest_end(skb, nest);
 623
 624         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 625                 goto nla_put_failure;
 626
 627         return skb->len;
 628
 629 nla_put_failure:
 630         nla_nest_cancel(skb, nest);
 631         return -1;
 632 }
 633
 634 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 635 {
 636         struct cls_bpf_prog *prog = fh;
 637
 638         if (prog && prog->res.classid == classid)
 639                 prog->res.class = cl;
 640 }
 641
 642 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 643 {
 644         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 645         struct cls_bpf_prog *prog;
 646
 647         list_for_each_entry(prog, &head->plist, link) {
 648                 if (arg->count < arg->skip)
 649                         goto skip;
 650                 if (arg->fn(tp, prog, arg) < 0) {
 651                         arg->stop = 1;
 652                         break;
 653                 }
 654 skip:
 655                 arg->count++;
 656         }
 657 }
 658
 659 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 660         .kind           =       "bpf",
 661         .owner          =       THIS_MODULE,
 662         .classify       =       cls_bpf_classify,
 663         .init           =       cls_bpf_init,
 664         .destroy        =       cls_bpf_destroy,
 665         .get            =       cls_bpf_get,
 666         .change         =       cls_bpf_change,
 667         .delete         =       cls_bpf_delete,
 668         .walk           =       cls_bpf_walk,
 669         .dump           =       cls_bpf_dump,
 670         .bind_class     =       cls_bpf_bind_class,
 671 };
 672
 673 static int __init cls_bpf_init_mod(void)
 674 {
 675         return register_tcf_proto_ops(&cls_bpf_ops);
 676 }
 677
 678 static void __exit cls_bpf_exit_mod(void)
 679 {
 680         unregister_tcf_proto_ops(&cls_bpf_ops);
 681 }
 682
 683 module_init(cls_bpf_init_mod);
 684 module_exit(cls_bpf_exit_mod);