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         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_pointers(skb);
 106                         filter_res = BPF_PROG_RUN(prog->filter, skb);
 107                         __skb_pull(skb, skb->mac_len);
 108                 } else {
 109                         bpf_compute_data_pointers(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                                struct cls_bpf_prog *oldprog)
 151 {
 152         struct tcf_block *block = tp->chain->block;
 153         struct tc_cls_bpf_offload cls_bpf = {};
 154         struct cls_bpf_prog *obj;
 155         bool skip_sw;
 156         int err;
 157
 158         skip_sw = prog && tc_skip_sw(prog->gen_flags);
 159         obj = prog ?: oldprog;
 160
 161         tc_cls_common_offload_init(&cls_bpf.common, tp);
 162         cls_bpf.command = TC_CLSBPF_OFFLOAD;
 163         cls_bpf.exts = &obj->exts;
 164         cls_bpf.prog = prog ? prog->filter : NULL;
 165         cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
 166         cls_bpf.name = obj->bpf_name;
 167         cls_bpf.exts_integrated = obj->exts_integrated;
 168         cls_bpf.gen_flags = obj->gen_flags;
 169
 170         err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
 171         if (prog) {
 172                 if (err < 0) {
 173                         cls_bpf_offload_cmd(tp, oldprog, prog);
 174                         return err;
 175                 } else if (err > 0) {
 176                         prog->gen_flags |= TCA_CLS_FLAGS_IN_HW;
 177                 }
 178         }
 179
 180         if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
 181                 return -EINVAL;
 182
 183         return 0;
 184 }
 185
 186 static u32 cls_bpf_flags(u32 flags)
 187 {
 188         return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
 189 }
 190
 191 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 192                            struct cls_bpf_prog *oldprog)
 193 {
 194         if (prog && oldprog &&
 195             cls_bpf_flags(prog->gen_flags) !=
 196             cls_bpf_flags(oldprog->gen_flags))
 197                 return -EINVAL;
 198
 199         if (prog && tc_skip_hw(prog->gen_flags))
 200                 prog = NULL;
 201         if (oldprog && tc_skip_hw(oldprog->gen_flags))
 202                 oldprog = NULL;
 203         if (!prog && !oldprog)
 204                 return 0;
 205
 206         return cls_bpf_offload_cmd(tp, prog, oldprog);
 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         err = cls_bpf_offload_cmd(tp, NULL, prog);
 215         if (err)
 216                 pr_err("Stopping hardware offload failed: %d\n", err);
 217 }
 218
 219 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 220                                          struct cls_bpf_prog *prog)
 221 {
 222         struct tcf_block *block = tp->chain->block;
 223         struct tc_cls_bpf_offload cls_bpf = {};
 224
 225         tc_cls_common_offload_init(&cls_bpf.common, tp);
 226         cls_bpf.command = TC_CLSBPF_STATS;
 227         cls_bpf.exts = &prog->exts;
 228         cls_bpf.prog = prog->filter;
 229         cls_bpf.name = prog->bpf_name;
 230         cls_bpf.exts_integrated = prog->exts_integrated;
 231         cls_bpf.gen_flags = prog->gen_flags;
 232
 233         tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 234 }
 235
 236 static int cls_bpf_init(struct tcf_proto *tp)
 237 {
 238         struct cls_bpf_head *head;
 239
 240         head = kzalloc(sizeof(*head), GFP_KERNEL);
 241         if (head == NULL)
 242                 return -ENOBUFS;
 243
 244         INIT_LIST_HEAD_RCU(&head->plist);
 245         idr_init(&head->handle_idr);
 246         rcu_assign_pointer(tp->root, head);
 247
 248         return 0;
 249 }
 250
 251 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
 252 {
 253         if (cls_bpf_is_ebpf(prog))
 254                 bpf_prog_put(prog->filter);
 255         else
 256                 bpf_prog_destroy(prog->filter);
 257
 258         kfree(prog->bpf_name);
 259         kfree(prog->bpf_ops);
 260 }
 261
 262 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 263 {
 264         tcf_exts_destroy(&prog->exts);
 265         tcf_exts_put_net(&prog->exts);
 266
 267         cls_bpf_free_parms(prog);
 268         kfree(prog);
 269 }
 270
 271 static void cls_bpf_delete_prog_work(struct work_struct *work)
 272 {
 273         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 274
 275         rtnl_lock();
 276         __cls_bpf_delete_prog(prog);
 277         rtnl_unlock();
 278 }
 279
 280 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 281 {
 282         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 283
 284         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 285         tcf_queue_work(&prog->work);
 286 }
 287
 288 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 289 {
 290         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 291
 292         idr_remove_ext(&head->handle_idr, prog->handle);
 293         cls_bpf_stop_offload(tp, prog);
 294         list_del_rcu(&prog->link);
 295         tcf_unbind_filter(tp, &prog->res);
 296         if (tcf_exts_get_net(&prog->exts))
 297                 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 298         else
 299                 __cls_bpf_delete_prog(prog);
 300 }
 301
 302 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last)
 303 {
 304         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 305
 306         __cls_bpf_delete(tp, arg);
 307         *last = list_empty(&head->plist);
 308         return 0;
 309 }
 310
 311 static void cls_bpf_destroy(struct tcf_proto *tp)
 312 {
 313         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 314         struct cls_bpf_prog *prog, *tmp;
 315
 316         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 317                 __cls_bpf_delete(tp, prog);
 318
 319         idr_destroy(&head->handle_idr);
 320         kfree_rcu(head, rcu);
 321 }
 322
 323 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 324 {
 325         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 326         struct cls_bpf_prog *prog;
 327
 328         list_for_each_entry(prog, &head->plist, link) {
 329                 if (prog->handle == handle)
 330                         return prog;
 331         }
 332
 333         return NULL;
 334 }
 335
 336 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 337 {
 338         struct sock_filter *bpf_ops;
 339         struct sock_fprog_kern fprog_tmp;
 340         struct bpf_prog *fp;
 341         u16 bpf_size, bpf_num_ops;
 342         int ret;
 343
 344         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 345         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 346                 return -EINVAL;
 347
 348         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 349         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 350                 return -EINVAL;
 351
 352         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 353         if (bpf_ops == NULL)
 354                 return -ENOMEM;
 355
 356         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 357
 358         fprog_tmp.len = bpf_num_ops;
 359         fprog_tmp.filter = bpf_ops;
 360
 361         ret = bpf_prog_create(&fp, &fprog_tmp);
 362         if (ret < 0) {
 363                 kfree(bpf_ops);
 364                 return ret;
 365         }
 366
 367         prog->bpf_ops = bpf_ops;
 368         prog->bpf_num_ops = bpf_num_ops;
 369         prog->bpf_name = NULL;
 370         prog->filter = fp;
 371
 372         return 0;
 373 }
 374
 375 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 376                                  u32 gen_flags, const struct tcf_proto *tp)
 377 {
 378         struct bpf_prog *fp;
 379         char *name = NULL;
 380         bool skip_sw;
 381         u32 bpf_fd;
 382
 383         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 384         skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
 385
 386         fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
 387         if (IS_ERR(fp))
 388                 return PTR_ERR(fp);
 389
 390         if (tb[TCA_BPF_NAME]) {
 391                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 392                 if (!name) {
 393                         bpf_prog_put(fp);
 394                         return -ENOMEM;
 395                 }
 396         }
 397
 398         prog->bpf_ops = NULL;
 399         prog->bpf_name = name;
 400         prog->filter = fp;
 401
 402         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 403                 netif_keep_dst(qdisc_dev(tp->q));
 404
 405         return 0;
 406 }
 407
 408 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 409                              struct cls_bpf_prog *prog, unsigned long base,
 410                              struct nlattr **tb, struct nlattr *est, bool ovr)
 411 {
 412         bool is_bpf, is_ebpf, have_exts = false;
 413         u32 gen_flags = 0;
 414         int ret;
 415
 416         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 417         is_ebpf = tb[TCA_BPF_FD];
 418         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 419                 return -EINVAL;
 420
 421         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr);
 422         if (ret < 0)
 423                 return ret;
 424
 425         if (tb[TCA_BPF_FLAGS]) {
 426                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 427
 428                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 429                         return -EINVAL;
 430
 431                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 432         }
 433         if (tb[TCA_BPF_FLAGS_GEN]) {
 434                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 435                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 436                     !tc_flags_valid(gen_flags))
 437                         return -EINVAL;
 438         }
 439
 440         prog->exts_integrated = have_exts;
 441         prog->gen_flags = gen_flags;
 442
 443         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 444                        cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
 445         if (ret < 0)
 446                 return ret;
 447
 448         if (tb[TCA_BPF_CLASSID]) {
 449                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 450                 tcf_bind_filter(tp, &prog->res, base);
 451         }
 452
 453         return 0;
 454 }
 455
 456 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 457                           struct tcf_proto *tp, unsigned long base,
 458                           u32 handle, struct nlattr **tca,
 459                           void **arg, bool ovr)
 460 {
 461         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 462         struct cls_bpf_prog *oldprog = *arg;
 463         struct nlattr *tb[TCA_BPF_MAX + 1];
 464         struct cls_bpf_prog *prog;
 465         unsigned long idr_index;
 466         int ret;
 467
 468         if (tca[TCA_OPTIONS] == NULL)
 469                 return -EINVAL;
 470
 471         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 472                                NULL);
 473         if (ret < 0)
 474                 return ret;
 475
 476         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 477         if (!prog)
 478                 return -ENOBUFS;
 479
 480         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 481         if (ret < 0)
 482                 goto errout;
 483
 484         if (oldprog) {
 485                 if (handle && oldprog->handle != handle) {
 486                         ret = -EINVAL;
 487                         goto errout;
 488                 }
 489         }
 490
 491         if (handle == 0) {
 492                 ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 493                                     1, 0x7FFFFFFF, GFP_KERNEL);
 494                 if (ret)
 495                         goto errout;
 496                 prog->handle = idr_index;
 497         } else {
 498                 if (!oldprog) {
 499                         ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 500                                             handle, handle + 1, GFP_KERNEL);
 501                         if (ret)
 502                                 goto errout;
 503                 }
 504                 prog->handle = handle;
 505         }
 506
 507         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
 508         if (ret < 0)
 509                 goto errout_idr;
 510
 511         ret = cls_bpf_offload(tp, prog, oldprog);
 512         if (ret)
 513                 goto errout_parms;
 514
 515         if (!tc_in_hw(prog->gen_flags))
 516                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 517
 518         if (oldprog) {
 519                 idr_replace_ext(&head->handle_idr, prog, handle);
 520                 list_replace_rcu(&oldprog->link, &prog->link);
 521                 tcf_unbind_filter(tp, &oldprog->res);
 522                 tcf_exts_get_net(&oldprog->exts);
 523                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 524         } else {
 525                 list_add_rcu(&prog->link, &head->plist);
 526         }
 527
 528         *arg = prog;
 529         return 0;
 530
 531 errout_parms:
 532         cls_bpf_free_parms(prog);
 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);