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