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                                struct netlink_ext_ack *extack)
 149 {
 150         struct tcf_block *block = tp->chain->block;
 151         struct tc_cls_bpf_offload cls_bpf = {};
 152         struct cls_bpf_prog *obj;
 153         bool skip_sw;
 154         int err;
 155
 156         skip_sw = prog && tc_skip_sw(prog->gen_flags);
 157         obj = prog ?: oldprog;
 158
 159         tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags,
 160                                    extack);
 161         cls_bpf.command = TC_CLSBPF_OFFLOAD;
 162         cls_bpf.exts = &obj->exts;
 163         cls_bpf.prog = prog ? prog->filter : NULL;
 164         cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
 165         cls_bpf.name = obj->bpf_name;
 166         cls_bpf.exts_integrated = obj->exts_integrated;
 167
 168         if (oldprog)
 169                 tcf_block_offload_dec(block, &oldprog->gen_flags);
 170
 171         err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
 172         if (prog) {
 173                 if (err < 0) {
 174                         cls_bpf_offload_cmd(tp, oldprog, prog, extack);
 175                         return err;
 176                 } else if (err > 0) {
 177                         tcf_block_offload_inc(block, &prog->gen_flags);
 178                 }
 179         }
 180
 181         if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
 182                 return -EINVAL;
 183
 184         return 0;
 185 }
 186
 187 static u32 cls_bpf_flags(u32 flags)
 188 {
 189         return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
 190 }
 191
 192 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 193                            struct cls_bpf_prog *oldprog,
 194                            struct netlink_ext_ack *extack)
 195 {
 196         if (prog && oldprog &&
 197             cls_bpf_flags(prog->gen_flags) !=
 198             cls_bpf_flags(oldprog->gen_flags))
 199                 return -EINVAL;
 200
 201         if (prog && tc_skip_hw(prog->gen_flags))
 202                 prog = NULL;
 203         if (oldprog && tc_skip_hw(oldprog->gen_flags))
 204                 oldprog = NULL;
 205         if (!prog && !oldprog)
 206                 return 0;
 207
 208         return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
 209 }
 210
 211 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 212                                  struct cls_bpf_prog *prog,
 213                                  struct netlink_ext_ack *extack)
 214 {
 215         int err;
 216
 217         err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
 218         if (err)
 219                 pr_err("Stopping hardware offload failed: %d\n", err);
 220 }
 221
 222 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 223                                          struct cls_bpf_prog *prog)
 224 {
 225         struct tcf_block *block = tp->chain->block;
 226         struct tc_cls_bpf_offload cls_bpf = {};
 227
 228         tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
 229         cls_bpf.command = TC_CLSBPF_STATS;
 230         cls_bpf.exts = &prog->exts;
 231         cls_bpf.prog = prog->filter;
 232         cls_bpf.name = prog->bpf_name;
 233         cls_bpf.exts_integrated = prog->exts_integrated;
 234
 235         tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 236 }
 237
 238 static int cls_bpf_init(struct tcf_proto *tp)
 239 {
 240         struct cls_bpf_head *head;
 241
 242         head = kzalloc(sizeof(*head), GFP_KERNEL);
 243         if (head == NULL)
 244                 return -ENOBUFS;
 245
 246         INIT_LIST_HEAD_RCU(&head->plist);
 247         idr_init(&head->handle_idr);
 248         rcu_assign_pointer(tp->root, head);
 249
 250         return 0;
 251 }
 252
 253 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
 254 {
 255         if (cls_bpf_is_ebpf(prog))
 256                 bpf_prog_put(prog->filter);
 257         else
 258                 bpf_prog_destroy(prog->filter);
 259
 260         kfree(prog->bpf_name);
 261         kfree(prog->bpf_ops);
 262 }
 263
 264 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 265 {
 266         tcf_exts_destroy(&prog->exts);
 267         tcf_exts_put_net(&prog->exts);
 268
 269         cls_bpf_free_parms(prog);
 270         kfree(prog);
 271 }
 272
 273 static void cls_bpf_delete_prog_work(struct work_struct *work)
 274 {
 275         struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
 276                                                  struct cls_bpf_prog,
 277                                                  rwork);
 278         rtnl_lock();
 279         __cls_bpf_delete_prog(prog);
 280         rtnl_unlock();
 281 }
 282
 283 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 284                              struct netlink_ext_ack *extack)
 285 {
 286         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 287
 288         idr_remove(&head->handle_idr, prog->handle);
 289         cls_bpf_stop_offload(tp, prog, extack);
 290         list_del_rcu(&prog->link);
 291         tcf_unbind_filter(tp, &prog->res);
 292         if (tcf_exts_get_net(&prog->exts))
 293                 tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
 294         else
 295                 __cls_bpf_delete_prog(prog);
 296 }
 297
 298 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
 299                           struct netlink_ext_ack *extack)
 300 {
 301         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 302
 303         __cls_bpf_delete(tp, arg, extack);
 304         *last = list_empty(&head->plist);
 305         return 0;
 306 }
 307
 308 static void cls_bpf_destroy(struct tcf_proto *tp,
 309                             struct netlink_ext_ack *extack)
 310 {
 311         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 312         struct cls_bpf_prog *prog, *tmp;
 313
 314         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 315                 __cls_bpf_delete(tp, prog, extack);
 316
 317         idr_destroy(&head->handle_idr);
 318         kfree_rcu(head, rcu);
 319 }
 320
 321 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 322 {
 323         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 324         struct cls_bpf_prog *prog;
 325
 326         list_for_each_entry(prog, &head->plist, link) {
 327                 if (prog->handle == handle)
 328                         return prog;
 329         }
 330
 331         return NULL;
 332 }
 333
 334 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 335 {
 336         struct sock_filter *bpf_ops;
 337         struct sock_fprog_kern fprog_tmp;
 338         struct bpf_prog *fp;
 339         u16 bpf_size, bpf_num_ops;
 340         int ret;
 341
 342         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 343         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 344                 return -EINVAL;
 345
 346         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 347         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 348                 return -EINVAL;
 349
 350         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 351         if (bpf_ops == NULL)
 352                 return -ENOMEM;
 353
 354         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 355
 356         fprog_tmp.len = bpf_num_ops;
 357         fprog_tmp.filter = bpf_ops;
 358
 359         ret = bpf_prog_create(&fp, &fprog_tmp);
 360         if (ret < 0) {
 361                 kfree(bpf_ops);
 362                 return ret;
 363         }
 364
 365         prog->bpf_ops = bpf_ops;
 366         prog->bpf_num_ops = bpf_num_ops;
 367         prog->bpf_name = NULL;
 368         prog->filter = fp;
 369
 370         return 0;
 371 }
 372
 373 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 374                                  u32 gen_flags, const struct tcf_proto *tp)
 375 {
 376         struct bpf_prog *fp;
 377         char *name = NULL;
 378         bool skip_sw;
 379         u32 bpf_fd;
 380
 381         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 382         skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
 383
 384         fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
 385         if (IS_ERR(fp))
 386                 return PTR_ERR(fp);
 387
 388         if (tb[TCA_BPF_NAME]) {
 389                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 390                 if (!name) {
 391                         bpf_prog_put(fp);
 392                         return -ENOMEM;
 393                 }
 394         }
 395
 396         prog->bpf_ops = NULL;
 397         prog->bpf_name = name;
 398         prog->filter = fp;
 399
 400         if (fp->dst_needed)
 401                 tcf_block_netif_keep_dst(tp->chain->block);
 402
 403         return 0;
 404 }
 405
 406 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 407                              struct cls_bpf_prog *prog, unsigned long base,
 408                              struct nlattr **tb, struct nlattr *est, bool ovr,
 409                              struct netlink_ext_ack *extack)
 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, extack);
 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, gen_flags, 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, struct netlink_ext_ack *extack)
 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         int ret;
 465
 466         if (tca[TCA_OPTIONS] == NULL)
 467                 return -EINVAL;
 468
 469         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 470                                NULL);
 471         if (ret < 0)
 472                 return ret;
 473
 474         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 475         if (!prog)
 476                 return -ENOBUFS;
 477
 478         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 479         if (ret < 0)
 480                 goto errout;
 481
 482         if (oldprog) {
 483                 if (handle && oldprog->handle != handle) {
 484                         ret = -EINVAL;
 485                         goto errout;
 486                 }
 487         }
 488
 489         if (handle == 0) {
 490                 handle = 1;
 491                 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
 492                                     INT_MAX, GFP_KERNEL);
 493         } else if (!oldprog) {
 494                 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
 495                                     handle, GFP_KERNEL);
 496         }
 497
 498         if (ret)
 499                 goto errout;
 500         prog->handle = handle;
 501
 502         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
 503                                 extack);
 504         if (ret < 0)
 505                 goto errout_idr;
 506
 507         ret = cls_bpf_offload(tp, prog, oldprog, extack);
 508         if (ret)
 509                 goto errout_parms;
 510
 511         if (!tc_in_hw(prog->gen_flags))
 512                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 513
 514         if (oldprog) {
 515                 idr_replace(&head->handle_idr, prog, handle);
 516                 list_replace_rcu(&oldprog->link, &prog->link);
 517                 tcf_unbind_filter(tp, &oldprog->res);
 518                 tcf_exts_get_net(&oldprog->exts);
 519                 tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
 520         } else {
 521                 list_add_rcu(&prog->link, &head->plist);
 522         }
 523
 524         *arg = prog;
 525         return 0;
 526
 527 errout_parms:
 528         cls_bpf_free_parms(prog);
 529 errout_idr:
 530         if (!oldprog)
 531                 idr_remove(&head->handle_idr, prog->handle);
 532 errout:
 533         tcf_exts_destroy(&prog->exts);
 534         kfree(prog);
 535         return ret;
 536 }
 537
 538 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 539                                  struct sk_buff *skb)
 540 {
 541         struct nlattr *nla;
 542
 543         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 544                 return -EMSGSIZE;
 545
 546         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 547                           sizeof(struct sock_filter));
 548         if (nla == NULL)
 549                 return -EMSGSIZE;
 550
 551         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 552
 553         return 0;
 554 }
 555
 556 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 557                                   struct sk_buff *skb)
 558 {
 559         struct nlattr *nla;
 560
 561         if (prog->bpf_name &&
 562             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 563                 return -EMSGSIZE;
 564
 565         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 566                 return -EMSGSIZE;
 567
 568         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 569         if (nla == NULL)
 570                 return -EMSGSIZE;
 571
 572         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 573
 574         return 0;
 575 }
 576
 577 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 578                         struct sk_buff *skb, struct tcmsg *tm)
 579 {
 580         struct cls_bpf_prog *prog = fh;
 581         struct nlattr *nest;
 582         u32 bpf_flags = 0;
 583         int ret;
 584
 585         if (prog == NULL)
 586                 return skb->len;
 587
 588         tm->tcm_handle = prog->handle;
 589
 590         cls_bpf_offload_update_stats(tp, prog);
 591
 592         nest = nla_nest_start(skb, TCA_OPTIONS);
 593         if (nest == NULL)
 594                 goto nla_put_failure;
 595
 596         if (prog->res.classid &&
 597             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 598                 goto nla_put_failure;
 599
 600         if (cls_bpf_is_ebpf(prog))
 601                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 602         else
 603                 ret = cls_bpf_dump_bpf_info(prog, skb);
 604         if (ret)
 605                 goto nla_put_failure;
 606
 607         if (tcf_exts_dump(skb, &prog->exts) < 0)
 608                 goto nla_put_failure;
 609
 610         if (prog->exts_integrated)
 611                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 612         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 613                 goto nla_put_failure;
 614         if (prog->gen_flags &&
 615             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 616                 goto nla_put_failure;
 617
 618         nla_nest_end(skb, nest);
 619
 620         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 621                 goto nla_put_failure;
 622
 623         return skb->len;
 624
 625 nla_put_failure:
 626         nla_nest_cancel(skb, nest);
 627         return -1;
 628 }
 629
 630 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 631 {
 632         struct cls_bpf_prog *prog = fh;
 633
 634         if (prog && prog->res.classid == classid)
 635                 prog->res.class = cl;
 636 }
 637
 638 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 639 {
 640         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 641         struct cls_bpf_prog *prog;
 642
 643         list_for_each_entry(prog, &head->plist, link) {
 644                 if (arg->count < arg->skip)
 645                         goto skip;
 646                 if (arg->fn(tp, prog, arg) < 0) {
 647                         arg->stop = 1;
 648                         break;
 649                 }
 650 skip:
 651                 arg->count++;
 652         }
 653 }
 654
 655 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 656         .kind           =       "bpf",
 657         .owner          =       THIS_MODULE,
 658         .classify       =       cls_bpf_classify,
 659         .init           =       cls_bpf_init,
 660         .destroy        =       cls_bpf_destroy,
 661         .get            =       cls_bpf_get,
 662         .change         =       cls_bpf_change,
 663         .delete         =       cls_bpf_delete,
 664         .walk           =       cls_bpf_walk,
 665         .dump           =       cls_bpf_dump,
 666         .bind_class     =       cls_bpf_bind_class,
 667 };
 668
 669 static int __init cls_bpf_init_mod(void)
 670 {
 671         return register_tcf_proto_ops(&cls_bpf_ops);
 672 }
 673
 674 static void __exit cls_bpf_exit_mod(void)
 675 {
 676         unregister_tcf_proto_ops(&cls_bpf_ops);
 677 }
 678
 679 module_init(cls_bpf_init_mod);
 680 module_exit(cls_bpf_exit_mod);