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                                struct netlink_ext_ack *extack)
 152 {
 153         struct tcf_block *block = tp->chain->block;
 154         struct tc_cls_bpf_offload cls_bpf = {};
 155         struct cls_bpf_prog *obj;
 156         bool skip_sw;
 157         int err;
 158
 159         skip_sw = prog && tc_skip_sw(prog->gen_flags);
 160         obj = prog ?: oldprog;
 161
 162         tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags,
 163                                    extack);
 164         cls_bpf.command = TC_CLSBPF_OFFLOAD;
 165         cls_bpf.exts = &obj->exts;
 166         cls_bpf.prog = prog ? prog->filter : NULL;
 167         cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
 168         cls_bpf.name = obj->bpf_name;
 169         cls_bpf.exts_integrated = obj->exts_integrated;
 170
 171         if (oldprog)
 172                 tcf_block_offload_dec(block, &oldprog->gen_flags);
 173
 174         err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
 175         if (prog) {
 176                 if (err < 0) {
 177                         cls_bpf_offload_cmd(tp, oldprog, prog, extack);
 178                         return err;
 179                 } else if (err > 0) {
 180                         tcf_block_offload_inc(block, &prog->gen_flags);
 181                 }
 182         }
 183
 184         if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
 185                 return -EINVAL;
 186
 187         return 0;
 188 }
 189
 190 static u32 cls_bpf_flags(u32 flags)
 191 {
 192         return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
 193 }
 194
 195 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 196                            struct cls_bpf_prog *oldprog,
 197                            struct netlink_ext_ack *extack)
 198 {
 199         if (prog && oldprog &&
 200             cls_bpf_flags(prog->gen_flags) !=
 201             cls_bpf_flags(oldprog->gen_flags))
 202                 return -EINVAL;
 203
 204         if (prog && tc_skip_hw(prog->gen_flags))
 205                 prog = NULL;
 206         if (oldprog && tc_skip_hw(oldprog->gen_flags))
 207                 oldprog = NULL;
 208         if (!prog && !oldprog)
 209                 return 0;
 210
 211         return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
 212 }
 213
 214 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 215                                  struct cls_bpf_prog *prog,
 216                                  struct netlink_ext_ack *extack)
 217 {
 218         int err;
 219
 220         err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
 221         if (err)
 222                 pr_err("Stopping hardware offload failed: %d\n", err);
 223 }
 224
 225 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 226                                          struct cls_bpf_prog *prog)
 227 {
 228         struct tcf_block *block = tp->chain->block;
 229         struct tc_cls_bpf_offload cls_bpf = {};
 230
 231         tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
 232         cls_bpf.command = TC_CLSBPF_STATS;
 233         cls_bpf.exts = &prog->exts;
 234         cls_bpf.prog = prog->filter;
 235         cls_bpf.name = prog->bpf_name;
 236         cls_bpf.exts_integrated = prog->exts_integrated;
 237
 238         tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 239 }
 240
 241 static int cls_bpf_init(struct tcf_proto *tp)
 242 {
 243         struct cls_bpf_head *head;
 244
 245         head = kzalloc(sizeof(*head), GFP_KERNEL);
 246         if (head == NULL)
 247                 return -ENOBUFS;
 248
 249         INIT_LIST_HEAD_RCU(&head->plist);
 250         idr_init(&head->handle_idr);
 251         rcu_assign_pointer(tp->root, head);
 252
 253         return 0;
 254 }
 255
 256 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
 257 {
 258         if (cls_bpf_is_ebpf(prog))
 259                 bpf_prog_put(prog->filter);
 260         else
 261                 bpf_prog_destroy(prog->filter);
 262
 263         kfree(prog->bpf_name);
 264         kfree(prog->bpf_ops);
 265 }
 266
 267 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 268 {
 269         tcf_exts_destroy(&prog->exts);
 270         tcf_exts_put_net(&prog->exts);
 271
 272         cls_bpf_free_parms(prog);
 273         kfree(prog);
 274 }
 275
 276 static void cls_bpf_delete_prog_work(struct work_struct *work)
 277 {
 278         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 279
 280         rtnl_lock();
 281         __cls_bpf_delete_prog(prog);
 282         rtnl_unlock();
 283 }
 284
 285 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 286 {
 287         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 288
 289         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 290         tcf_queue_work(&prog->work);
 291 }
 292
 293 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 294                              struct netlink_ext_ack *extack)
 295 {
 296         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 297
 298         idr_remove(&head->handle_idr, prog->handle);
 299         cls_bpf_stop_offload(tp, prog, extack);
 300         list_del_rcu(&prog->link);
 301         tcf_unbind_filter(tp, &prog->res);
 302         if (tcf_exts_get_net(&prog->exts))
 303                 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 304         else
 305                 __cls_bpf_delete_prog(prog);
 306 }
 307
 308 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
 309                           struct netlink_ext_ack *extack)
 310 {
 311         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 312
 313         __cls_bpf_delete(tp, arg, extack);
 314         *last = list_empty(&head->plist);
 315         return 0;
 316 }
 317
 318 static void cls_bpf_destroy(struct tcf_proto *tp,
 319                             struct netlink_ext_ack *extack)
 320 {
 321         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 322         struct cls_bpf_prog *prog, *tmp;
 323
 324         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 325                 __cls_bpf_delete(tp, prog, extack);
 326
 327         idr_destroy(&head->handle_idr);
 328         kfree_rcu(head, rcu);
 329 }
 330
 331 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 332 {
 333         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 334         struct cls_bpf_prog *prog;
 335
 336         list_for_each_entry(prog, &head->plist, link) {
 337                 if (prog->handle == handle)
 338                         return prog;
 339         }
 340
 341         return NULL;
 342 }
 343
 344 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 345 {
 346         struct sock_filter *bpf_ops;
 347         struct sock_fprog_kern fprog_tmp;
 348         struct bpf_prog *fp;
 349         u16 bpf_size, bpf_num_ops;
 350         int ret;
 351
 352         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 353         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 354                 return -EINVAL;
 355
 356         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 357         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 358                 return -EINVAL;
 359
 360         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 361         if (bpf_ops == NULL)
 362                 return -ENOMEM;
 363
 364         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 365
 366         fprog_tmp.len = bpf_num_ops;
 367         fprog_tmp.filter = bpf_ops;
 368
 369         ret = bpf_prog_create(&fp, &fprog_tmp);
 370         if (ret < 0) {
 371                 kfree(bpf_ops);
 372                 return ret;
 373         }
 374
 375         prog->bpf_ops = bpf_ops;
 376         prog->bpf_num_ops = bpf_num_ops;
 377         prog->bpf_name = NULL;
 378         prog->filter = fp;
 379
 380         return 0;
 381 }
 382
 383 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 384                                  u32 gen_flags, const struct tcf_proto *tp)
 385 {
 386         struct bpf_prog *fp;
 387         char *name = NULL;
 388         bool skip_sw;
 389         u32 bpf_fd;
 390
 391         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 392         skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
 393
 394         fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
 395         if (IS_ERR(fp))
 396                 return PTR_ERR(fp);
 397
 398         if (tb[TCA_BPF_NAME]) {
 399                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 400                 if (!name) {
 401                         bpf_prog_put(fp);
 402                         return -ENOMEM;
 403                 }
 404         }
 405
 406         prog->bpf_ops = NULL;
 407         prog->bpf_name = name;
 408         prog->filter = fp;
 409
 410         if (fp->dst_needed)
 411                 tcf_block_netif_keep_dst(tp->chain->block);
 412
 413         return 0;
 414 }
 415
 416 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 417                              struct cls_bpf_prog *prog, unsigned long base,
 418                              struct nlattr **tb, struct nlattr *est, bool ovr,
 419                              struct netlink_ext_ack *extack)
 420 {
 421         bool is_bpf, is_ebpf, have_exts = false;
 422         u32 gen_flags = 0;
 423         int ret;
 424
 425         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 426         is_ebpf = tb[TCA_BPF_FD];
 427         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 428                 return -EINVAL;
 429
 430         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr, extack);
 431         if (ret < 0)
 432                 return ret;
 433
 434         if (tb[TCA_BPF_FLAGS]) {
 435                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 436
 437                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 438                         return -EINVAL;
 439
 440                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 441         }
 442         if (tb[TCA_BPF_FLAGS_GEN]) {
 443                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 444                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 445                     !tc_flags_valid(gen_flags))
 446                         return -EINVAL;
 447         }
 448
 449         prog->exts_integrated = have_exts;
 450         prog->gen_flags = gen_flags;
 451
 452         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 453                        cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
 454         if (ret < 0)
 455                 return ret;
 456
 457         if (tb[TCA_BPF_CLASSID]) {
 458                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 459                 tcf_bind_filter(tp, &prog->res, base);
 460         }
 461
 462         return 0;
 463 }
 464
 465 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 466                           struct tcf_proto *tp, unsigned long base,
 467                           u32 handle, struct nlattr **tca,
 468                           void **arg, bool ovr, struct netlink_ext_ack *extack)
 469 {
 470         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 471         struct cls_bpf_prog *oldprog = *arg;
 472         struct nlattr *tb[TCA_BPF_MAX + 1];
 473         struct cls_bpf_prog *prog;
 474         int ret;
 475
 476         if (tca[TCA_OPTIONS] == NULL)
 477                 return -EINVAL;
 478
 479         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 480                                NULL);
 481         if (ret < 0)
 482                 return ret;
 483
 484         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 485         if (!prog)
 486                 return -ENOBUFS;
 487
 488         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 489         if (ret < 0)
 490                 goto errout;
 491
 492         if (oldprog) {
 493                 if (handle && oldprog->handle != handle) {
 494                         ret = -EINVAL;
 495                         goto errout;
 496                 }
 497         }
 498
 499         if (handle == 0) {
 500                 handle = 1;
 501                 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
 502                                     INT_MAX, GFP_KERNEL);
 503         } else if (!oldprog) {
 504                 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
 505                                     handle, GFP_KERNEL);
 506         }
 507
 508         if (ret)
 509                 goto errout;
 510         prog->handle = handle;
 511
 512         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
 513                                 extack);
 514         if (ret < 0)
 515                 goto errout_idr;
 516
 517         ret = cls_bpf_offload(tp, prog, oldprog, extack);
 518         if (ret)
 519                 goto errout_parms;
 520
 521         if (!tc_in_hw(prog->gen_flags))
 522                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 523
 524         if (oldprog) {
 525                 idr_replace(&head->handle_idr, prog, handle);
 526                 list_replace_rcu(&oldprog->link, &prog->link);
 527                 tcf_unbind_filter(tp, &oldprog->res);
 528                 tcf_exts_get_net(&oldprog->exts);
 529                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 530         } else {
 531                 list_add_rcu(&prog->link, &head->plist);
 532         }
 533
 534         *arg = prog;
 535         return 0;
 536
 537 errout_parms:
 538         cls_bpf_free_parms(prog);
 539 errout_idr:
 540         if (!oldprog)
 541                 idr_remove(&head->handle_idr, prog->handle);
 542 errout:
 543         tcf_exts_destroy(&prog->exts);
 544         kfree(prog);
 545         return ret;
 546 }
 547
 548 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 549                                  struct sk_buff *skb)
 550 {
 551         struct nlattr *nla;
 552
 553         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 554                 return -EMSGSIZE;
 555
 556         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 557                           sizeof(struct sock_filter));
 558         if (nla == NULL)
 559                 return -EMSGSIZE;
 560
 561         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 562
 563         return 0;
 564 }
 565
 566 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 567                                   struct sk_buff *skb)
 568 {
 569         struct nlattr *nla;
 570
 571         if (prog->bpf_name &&
 572             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 573                 return -EMSGSIZE;
 574
 575         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 576                 return -EMSGSIZE;
 577
 578         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 579         if (nla == NULL)
 580                 return -EMSGSIZE;
 581
 582         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 583
 584         return 0;
 585 }
 586
 587 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 588                         struct sk_buff *skb, struct tcmsg *tm)
 589 {
 590         struct cls_bpf_prog *prog = fh;
 591         struct nlattr *nest;
 592         u32 bpf_flags = 0;
 593         int ret;
 594
 595         if (prog == NULL)
 596                 return skb->len;
 597
 598         tm->tcm_handle = prog->handle;
 599
 600         cls_bpf_offload_update_stats(tp, prog);
 601
 602         nest = nla_nest_start(skb, TCA_OPTIONS);
 603         if (nest == NULL)
 604                 goto nla_put_failure;
 605
 606         if (prog->res.classid &&
 607             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 608                 goto nla_put_failure;
 609
 610         if (cls_bpf_is_ebpf(prog))
 611                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 612         else
 613                 ret = cls_bpf_dump_bpf_info(prog, skb);
 614         if (ret)
 615                 goto nla_put_failure;
 616
 617         if (tcf_exts_dump(skb, &prog->exts) < 0)
 618                 goto nla_put_failure;
 619
 620         if (prog->exts_integrated)
 621                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 622         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 623                 goto nla_put_failure;
 624         if (prog->gen_flags &&
 625             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 626                 goto nla_put_failure;
 627
 628         nla_nest_end(skb, nest);
 629
 630         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 631                 goto nla_put_failure;
 632
 633         return skb->len;
 634
 635 nla_put_failure:
 636         nla_nest_cancel(skb, nest);
 637         return -1;
 638 }
 639
 640 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 641 {
 642         struct cls_bpf_prog *prog = fh;
 643
 644         if (prog && prog->res.classid == classid)
 645                 prog->res.class = cl;
 646 }
 647
 648 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 649 {
 650         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 651         struct cls_bpf_prog *prog;
 652
 653         list_for_each_entry(prog, &head->plist, link) {
 654                 if (arg->count < arg->skip)
 655                         goto skip;
 656                 if (arg->fn(tp, prog, arg) < 0) {
 657                         arg->stop = 1;
 658                         break;
 659                 }
 660 skip:
 661                 arg->count++;
 662         }
 663 }
 664
 665 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 666         .kind           =       "bpf",
 667         .owner          =       THIS_MODULE,
 668         .classify       =       cls_bpf_classify,
 669         .init           =       cls_bpf_init,
 670         .destroy        =       cls_bpf_destroy,
 671         .get            =       cls_bpf_get,
 672         .change         =       cls_bpf_change,
 673         .delete         =       cls_bpf_delete,
 674         .walk           =       cls_bpf_walk,
 675         .dump           =       cls_bpf_dump,
 676         .bind_class     =       cls_bpf_bind_class,
 677 };
 678
 679 static int __init cls_bpf_init_mod(void)
 680 {
 681         return register_tcf_proto_ops(&cls_bpf_ops);
 682 }
 683
 684 static void __exit cls_bpf_exit_mod(void)
 685 {
 686         unregister_tcf_proto_ops(&cls_bpf_ops);
 687 }
 688
 689 module_init(cls_bpf_init_mod);
 690 module_exit(cls_bpf_exit_mod);