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 int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 187                            struct cls_bpf_prog *oldprog)
 188 {
 189         if (prog && oldprog && prog->gen_flags != oldprog->gen_flags)
 190                 return -EINVAL;
 191
 192         if (prog && tc_skip_hw(prog->gen_flags))
 193                 prog = NULL;
 194         if (oldprog && tc_skip_hw(oldprog->gen_flags))
 195                 oldprog = NULL;
 196         if (!prog && !oldprog)
 197                 return 0;
 198
 199         return cls_bpf_offload_cmd(tp, prog, oldprog);
 200 }
 201
 202 static void cls_bpf_stop_offload(struct tcf_proto *tp,
 203                                  struct cls_bpf_prog *prog)
 204 {
 205         int err;
 206
 207         err = cls_bpf_offload_cmd(tp, NULL, prog);
 208         if (err)
 209                 pr_err("Stopping hardware offload failed: %d\n", err);
 210 }
 211
 212 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 213                                          struct cls_bpf_prog *prog)
 214 {
 215         struct tcf_block *block = tp->chain->block;
 216         struct tc_cls_bpf_offload cls_bpf = {};
 217
 218         tc_cls_common_offload_init(&cls_bpf.common, tp);
 219         cls_bpf.command = TC_CLSBPF_STATS;
 220         cls_bpf.exts = &prog->exts;
 221         cls_bpf.prog = prog->filter;
 222         cls_bpf.name = prog->bpf_name;
 223         cls_bpf.exts_integrated = prog->exts_integrated;
 224         cls_bpf.gen_flags = prog->gen_flags;
 225
 226         tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 227 }
 228
 229 static int cls_bpf_init(struct tcf_proto *tp)
 230 {
 231         struct cls_bpf_head *head;
 232
 233         head = kzalloc(sizeof(*head), GFP_KERNEL);
 234         if (head == NULL)
 235                 return -ENOBUFS;
 236
 237         INIT_LIST_HEAD_RCU(&head->plist);
 238         idr_init(&head->handle_idr);
 239         rcu_assign_pointer(tp->root, head);
 240
 241         return 0;
 242 }
 243
 244 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
 245 {
 246         if (cls_bpf_is_ebpf(prog))
 247                 bpf_prog_put(prog->filter);
 248         else
 249                 bpf_prog_destroy(prog->filter);
 250
 251         kfree(prog->bpf_name);
 252         kfree(prog->bpf_ops);
 253 }
 254
 255 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 256 {
 257         tcf_exts_destroy(&prog->exts);
 258         tcf_exts_put_net(&prog->exts);
 259
 260         cls_bpf_free_parms(prog);
 261         kfree(prog);
 262 }
 263
 264 static void cls_bpf_delete_prog_work(struct work_struct *work)
 265 {
 266         struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
 267
 268         rtnl_lock();
 269         __cls_bpf_delete_prog(prog);
 270         rtnl_unlock();
 271 }
 272
 273 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 274 {
 275         struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
 276
 277         INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
 278         tcf_queue_work(&prog->work);
 279 }
 280
 281 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 282 {
 283         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 284
 285         idr_remove_ext(&head->handle_idr, prog->handle);
 286         cls_bpf_stop_offload(tp, prog);
 287         list_del_rcu(&prog->link);
 288         tcf_unbind_filter(tp, &prog->res);
 289         if (tcf_exts_get_net(&prog->exts))
 290                 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
 291         else
 292                 __cls_bpf_delete_prog(prog);
 293 }
 294
 295 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last)
 296 {
 297         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 298
 299         __cls_bpf_delete(tp, arg);
 300         *last = list_empty(&head->plist);
 301         return 0;
 302 }
 303
 304 static void cls_bpf_destroy(struct tcf_proto *tp)
 305 {
 306         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 307         struct cls_bpf_prog *prog, *tmp;
 308
 309         list_for_each_entry_safe(prog, tmp, &head->plist, link)
 310                 __cls_bpf_delete(tp, prog);
 311
 312         idr_destroy(&head->handle_idr);
 313         kfree_rcu(head, rcu);
 314 }
 315
 316 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
 317 {
 318         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 319         struct cls_bpf_prog *prog;
 320
 321         list_for_each_entry(prog, &head->plist, link) {
 322                 if (prog->handle == handle)
 323                         return prog;
 324         }
 325
 326         return NULL;
 327 }
 328
 329 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
 330 {
 331         struct sock_filter *bpf_ops;
 332         struct sock_fprog_kern fprog_tmp;
 333         struct bpf_prog *fp;
 334         u16 bpf_size, bpf_num_ops;
 335         int ret;
 336
 337         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
 338         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
 339                 return -EINVAL;
 340
 341         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
 342         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
 343                 return -EINVAL;
 344
 345         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
 346         if (bpf_ops == NULL)
 347                 return -ENOMEM;
 348
 349         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
 350
 351         fprog_tmp.len = bpf_num_ops;
 352         fprog_tmp.filter = bpf_ops;
 353
 354         ret = bpf_prog_create(&fp, &fprog_tmp);
 355         if (ret < 0) {
 356                 kfree(bpf_ops);
 357                 return ret;
 358         }
 359
 360         prog->bpf_ops = bpf_ops;
 361         prog->bpf_num_ops = bpf_num_ops;
 362         prog->bpf_name = NULL;
 363         prog->filter = fp;
 364
 365         return 0;
 366 }
 367
 368 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 369                                  u32 gen_flags, const struct tcf_proto *tp)
 370 {
 371         struct bpf_prog *fp;
 372         char *name = NULL;
 373         bool skip_sw;
 374         u32 bpf_fd;
 375
 376         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 377         skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
 378
 379         fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
 380         if (IS_ERR(fp))
 381                 return PTR_ERR(fp);
 382
 383         if (tb[TCA_BPF_NAME]) {
 384                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 385                 if (!name) {
 386                         bpf_prog_put(fp);
 387                         return -ENOMEM;
 388                 }
 389         }
 390
 391         prog->bpf_ops = NULL;
 392         prog->bpf_name = name;
 393         prog->filter = fp;
 394
 395         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
 396                 netif_keep_dst(qdisc_dev(tp->q));
 397
 398         return 0;
 399 }
 400
 401 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
 402                              struct cls_bpf_prog *prog, unsigned long base,
 403                              struct nlattr **tb, struct nlattr *est, bool ovr)
 404 {
 405         bool is_bpf, is_ebpf, have_exts = false;
 406         u32 gen_flags = 0;
 407         int ret;
 408
 409         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
 410         is_ebpf = tb[TCA_BPF_FD];
 411         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
 412                 return -EINVAL;
 413
 414         ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr);
 415         if (ret < 0)
 416                 return ret;
 417
 418         if (tb[TCA_BPF_FLAGS]) {
 419                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
 420
 421                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
 422                         return -EINVAL;
 423
 424                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
 425         }
 426         if (tb[TCA_BPF_FLAGS_GEN]) {
 427                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
 428                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
 429                     !tc_flags_valid(gen_flags))
 430                         return -EINVAL;
 431         }
 432
 433         prog->exts_integrated = have_exts;
 434         prog->gen_flags = gen_flags;
 435
 436         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
 437                        cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
 438         if (ret < 0)
 439                 return ret;
 440
 441         if (tb[TCA_BPF_CLASSID]) {
 442                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
 443                 tcf_bind_filter(tp, &prog->res, base);
 444         }
 445
 446         return 0;
 447 }
 448
 449 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 450                           struct tcf_proto *tp, unsigned long base,
 451                           u32 handle, struct nlattr **tca,
 452                           void **arg, bool ovr)
 453 {
 454         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 455         struct cls_bpf_prog *oldprog = *arg;
 456         struct nlattr *tb[TCA_BPF_MAX + 1];
 457         struct cls_bpf_prog *prog;
 458         unsigned long idr_index;
 459         int ret;
 460
 461         if (tca[TCA_OPTIONS] == NULL)
 462                 return -EINVAL;
 463
 464         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
 465                                NULL);
 466         if (ret < 0)
 467                 return ret;
 468
 469         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 470         if (!prog)
 471                 return -ENOBUFS;
 472
 473         ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
 474         if (ret < 0)
 475                 goto errout;
 476
 477         if (oldprog) {
 478                 if (handle && oldprog->handle != handle) {
 479                         ret = -EINVAL;
 480                         goto errout;
 481                 }
 482         }
 483
 484         if (handle == 0) {
 485                 ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 486                                     1, 0x7FFFFFFF, GFP_KERNEL);
 487                 if (ret)
 488                         goto errout;
 489                 prog->handle = idr_index;
 490         } else {
 491                 if (!oldprog) {
 492                         ret = idr_alloc_ext(&head->handle_idr, prog, &idr_index,
 493                                             handle, handle + 1, GFP_KERNEL);
 494                         if (ret)
 495                                 goto errout;
 496                 }
 497                 prog->handle = handle;
 498         }
 499
 500         ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
 501         if (ret < 0)
 502                 goto errout_idr;
 503
 504         ret = cls_bpf_offload(tp, prog, oldprog);
 505         if (ret)
 506                 goto errout_parms;
 507
 508         if (!tc_in_hw(prog->gen_flags))
 509                 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 510
 511         if (oldprog) {
 512                 idr_replace_ext(&head->handle_idr, prog, handle);
 513                 list_replace_rcu(&oldprog->link, &prog->link);
 514                 tcf_unbind_filter(tp, &oldprog->res);
 515                 tcf_exts_get_net(&oldprog->exts);
 516                 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
 517         } else {
 518                 list_add_rcu(&prog->link, &head->plist);
 519         }
 520
 521         *arg = prog;
 522         return 0;
 523
 524 errout_parms:
 525         cls_bpf_free_parms(prog);
 526 errout_idr:
 527         if (!oldprog)
 528                 idr_remove_ext(&head->handle_idr, prog->handle);
 529 errout:
 530         tcf_exts_destroy(&prog->exts);
 531         kfree(prog);
 532         return ret;
 533 }
 534
 535 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
 536                                  struct sk_buff *skb)
 537 {
 538         struct nlattr *nla;
 539
 540         if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
 541                 return -EMSGSIZE;
 542
 543         nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
 544                           sizeof(struct sock_filter));
 545         if (nla == NULL)
 546                 return -EMSGSIZE;
 547
 548         memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
 549
 550         return 0;
 551 }
 552
 553 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
 554                                   struct sk_buff *skb)
 555 {
 556         struct nlattr *nla;
 557
 558         if (prog->bpf_name &&
 559             nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
 560                 return -EMSGSIZE;
 561
 562         if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
 563                 return -EMSGSIZE;
 564
 565         nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
 566         if (nla == NULL)
 567                 return -EMSGSIZE;
 568
 569         memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
 570
 571         return 0;
 572 }
 573
 574 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
 575                         struct sk_buff *skb, struct tcmsg *tm)
 576 {
 577         struct cls_bpf_prog *prog = fh;
 578         struct nlattr *nest;
 579         u32 bpf_flags = 0;
 580         int ret;
 581
 582         if (prog == NULL)
 583                 return skb->len;
 584
 585         tm->tcm_handle = prog->handle;
 586
 587         cls_bpf_offload_update_stats(tp, prog);
 588
 589         nest = nla_nest_start(skb, TCA_OPTIONS);
 590         if (nest == NULL)
 591                 goto nla_put_failure;
 592
 593         if (prog->res.classid &&
 594             nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
 595                 goto nla_put_failure;
 596
 597         if (cls_bpf_is_ebpf(prog))
 598                 ret = cls_bpf_dump_ebpf_info(prog, skb);
 599         else
 600                 ret = cls_bpf_dump_bpf_info(prog, skb);
 601         if (ret)
 602                 goto nla_put_failure;
 603
 604         if (tcf_exts_dump(skb, &prog->exts) < 0)
 605                 goto nla_put_failure;
 606
 607         if (prog->exts_integrated)
 608                 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 609         if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
 610                 goto nla_put_failure;
 611         if (prog->gen_flags &&
 612             nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
 613                 goto nla_put_failure;
 614
 615         nla_nest_end(skb, nest);
 616
 617         if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
 618                 goto nla_put_failure;
 619
 620         return skb->len;
 621
 622 nla_put_failure:
 623         nla_nest_cancel(skb, nest);
 624         return -1;
 625 }
 626
 627 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
 628 {
 629         struct cls_bpf_prog *prog = fh;
 630
 631         if (prog && prog->res.classid == classid)
 632                 prog->res.class = cl;
 633 }
 634
 635 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 636 {
 637         struct cls_bpf_head *head = rtnl_dereference(tp->root);
 638         struct cls_bpf_prog *prog;
 639
 640         list_for_each_entry(prog, &head->plist, link) {
 641                 if (arg->count < arg->skip)
 642                         goto skip;
 643                 if (arg->fn(tp, prog, arg) < 0) {
 644                         arg->stop = 1;
 645                         break;
 646                 }
 647 skip:
 648                 arg->count++;
 649         }
 650 }
 651
 652 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
 653         .kind           =       "bpf",
 654         .owner          =       THIS_MODULE,
 655         .classify       =       cls_bpf_classify,
 656         .init           =       cls_bpf_init,
 657         .destroy        =       cls_bpf_destroy,
 658         .get            =       cls_bpf_get,
 659         .change         =       cls_bpf_change,
 660         .delete         =       cls_bpf_delete,
 661         .walk           =       cls_bpf_walk,
 662         .dump           =       cls_bpf_dump,
 663         .bind_class     =       cls_bpf_bind_class,
 664 };
 665
 666 static int __init cls_bpf_init_mod(void)
 667 {
 668         return register_tcf_proto_ops(&cls_bpf_ops);
 669 }
 670
 671 static void __exit cls_bpf_exit_mod(void)
 672 {
 673         unregister_tcf_proto_ops(&cls_bpf_ops);
 674 }
 675
 676 module_init(cls_bpf_init_mod);
 677 module_exit(cls_bpf_exit_mod);