net/sched/cls_api.c

   1 /*
   2  * net/sched/cls_api.c  Packet classifier API.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  * Changes:
  12  *
  13  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/err.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/init.h>
  25 #include <linux/kmod.h>
  26 #include <linux/err.h>
  27 #include <linux/slab.h>
  28 #include <net/net_namespace.h>
  29 #include <net/sock.h>
  30 #include <net/netlink.h>
  31 #include <net/pkt_sched.h>
  32 #include <net/pkt_cls.h>
  33
  34 /* The list of all installed classifier types */
  35 static LIST_HEAD(tcf_proto_base);
  36
  37 /* Protects list of registered TC modules. It is pure SMP lock. */
  38 static DEFINE_RWLOCK(cls_mod_lock);
  39
  40 /* Find classifier type by string name */
  41
  42 static const struct tcf_proto_ops *tcf_proto_lookup_ops(const char *kind)
  43 {
  44         const struct tcf_proto_ops *t, *res = NULL;
  45
  46         if (kind) {
  47                 read_lock(&cls_mod_lock);
  48                 list_for_each_entry(t, &tcf_proto_base, head) {
  49                         if (strcmp(kind, t->kind) == 0) {
  50                                 if (try_module_get(t->owner))
  51                                         res = t;
  52                                 break;
  53                         }
  54                 }
  55                 read_unlock(&cls_mod_lock);
  56         }
  57         return res;
  58 }
  59
  60 /* Register(unregister) new classifier type */
  61
  62 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  63 {
  64         struct tcf_proto_ops *t;
  65         int rc = -EEXIST;
  66
  67         write_lock(&cls_mod_lock);
  68         list_for_each_entry(t, &tcf_proto_base, head)
  69                 if (!strcmp(ops->kind, t->kind))
  70                         goto out;
  71
  72         list_add_tail(&ops->head, &tcf_proto_base);
  73         rc = 0;
  74 out:
  75         write_unlock(&cls_mod_lock);
  76         return rc;
  77 }
  78 EXPORT_SYMBOL(register_tcf_proto_ops);
  79
  80 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  81 {
  82         struct tcf_proto_ops *t;
  83         int rc = -ENOENT;
  84
  85         /* Wait for outstanding call_rcu()s, if any, from a
  86          * tcf_proto_ops's destroy() handler.
  87          */
  88         rcu_barrier();
  89
  90         write_lock(&cls_mod_lock);
  91         list_for_each_entry(t, &tcf_proto_base, head) {
  92                 if (t == ops) {
  93                         list_del(&t->head);
  94                         rc = 0;
  95                         break;
  96                 }
  97         }
  98         write_unlock(&cls_mod_lock);
  99         return rc;
 100 }
 101 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 102
 103 /* Select new prio value from the range, managed by kernel. */
 104
 105 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 106 {
 107         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 108
 109         if (tp)
 110                 first = tp->prio - 1;
 111
 112         return TC_H_MAJ(first);
 113 }
 114
 115 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
 116                                           u32 prio, u32 parent, struct Qdisc *q,
 117                                           struct tcf_chain *chain)
 118 {
 119         struct tcf_proto *tp;
 120         int err;
 121
 122         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 123         if (!tp)
 124                 return ERR_PTR(-ENOBUFS);
 125
 126         err = -ENOENT;
 127         tp->ops = tcf_proto_lookup_ops(kind);
 128         if (!tp->ops) {
 129 #ifdef CONFIG_MODULES
 130                 rtnl_unlock();
 131                 request_module("cls_%s", kind);
 132                 rtnl_lock();
 133                 tp->ops = tcf_proto_lookup_ops(kind);
 134                 /* We dropped the RTNL semaphore in order to perform
 135                  * the module load. So, even if we succeeded in loading
 136                  * the module we have to replay the request. We indicate
 137                  * this using -EAGAIN.
 138                  */
 139                 if (tp->ops) {
 140                         module_put(tp->ops->owner);
 141                         err = -EAGAIN;
 142                 } else {
 143                         err = -ENOENT;
 144                 }
 145                 goto errout;
 146 #endif
 147         }
 148         tp->classify = tp->ops->classify;
 149         tp->protocol = protocol;
 150         tp->prio = prio;
 151         tp->classid = parent;
 152         tp->q = q;
 153         tp->chain = chain;
 154
 155         err = tp->ops->init(tp);
 156         if (err) {
 157                 module_put(tp->ops->owner);
 158                 goto errout;
 159         }
 160         return tp;
 161
 162 errout:
 163         kfree(tp);
 164         return ERR_PTR(err);
 165 }
 166
 167 static void tcf_proto_destroy(struct tcf_proto *tp)
 168 {
 169         tp->ops->destroy(tp);
 170         module_put(tp->ops->owner);
 171         kfree_rcu(tp, rcu);
 172 }
 173
 174 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 175                                           u32 chain_index)
 176 {
 177         struct tcf_chain *chain;
 178
 179         chain = kzalloc(sizeof(*chain), GFP_KERNEL);
 180         if (!chain)
 181                 return NULL;
 182         list_add_tail(&chain->list, &block->chain_list);
 183         chain->block = block;
 184         chain->index = chain_index;
 185         chain->refcnt = 1;
 186         return chain;
 187 }
 188
 189 static void tcf_chain_flush(struct tcf_chain *chain)
 190 {
 191         struct tcf_proto *tp;
 192
 193         if (chain->p_filter_chain)
 194                 RCU_INIT_POINTER(*chain->p_filter_chain, NULL);
 195         while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) {
 196                 RCU_INIT_POINTER(chain->filter_chain, tp->next);
 197                 tcf_chain_put(chain);
 198                 tcf_proto_destroy(tp);
 199         }
 200 }
 201
 202 static void tcf_chain_destroy(struct tcf_chain *chain)
 203 {
 204         list_del(&chain->list);
 205         kfree(chain);
 206 }
 207
 208 static void tcf_chain_hold(struct tcf_chain *chain)
 209 {
 210         ++chain->refcnt;
 211 }
 212
 213 struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
 214                                 bool create)
 215 {
 216         struct tcf_chain *chain;
 217
 218         list_for_each_entry(chain, &block->chain_list, list) {
 219                 if (chain->index == chain_index) {
 220                         tcf_chain_hold(chain);
 221                         return chain;
 222                 }
 223         }
 224
 225         return create ? tcf_chain_create(block, chain_index) : NULL;
 226 }
 227 EXPORT_SYMBOL(tcf_chain_get);
 228
 229 void tcf_chain_put(struct tcf_chain *chain)
 230 {
 231         if (--chain->refcnt == 0)
 232                 tcf_chain_destroy(chain);
 233 }
 234 EXPORT_SYMBOL(tcf_chain_put);
 235
 236 static void
 237 tcf_chain_filter_chain_ptr_set(struct tcf_chain *chain,
 238                                struct tcf_proto __rcu **p_filter_chain)
 239 {
 240         chain->p_filter_chain = p_filter_chain;
 241 }
 242
 243 int tcf_block_get(struct tcf_block **p_block,
 244                   struct tcf_proto __rcu **p_filter_chain)
 245 {
 246         struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
 247         struct tcf_chain *chain;
 248         int err;
 249
 250         if (!block)
 251                 return -ENOMEM;
 252         INIT_LIST_HEAD(&block->chain_list);
 253         /* Create chain 0 by default, it has to be always present. */
 254         chain = tcf_chain_create(block, 0);
 255         if (!chain) {
 256                 err = -ENOMEM;
 257                 goto err_chain_create;
 258         }
 259         tcf_chain_filter_chain_ptr_set(chain, p_filter_chain);
 260         *p_block = block;
 261         return 0;
 262
 263 err_chain_create:
 264         kfree(block);
 265         return err;
 266 }
 267 EXPORT_SYMBOL(tcf_block_get);
 268
 269 void tcf_block_put(struct tcf_block *block)
 270 {
 271         struct tcf_chain *chain, *tmp;
 272
 273         if (!block)
 274                 return;
 275
 276         /* XXX: Standalone actions are not allowed to jump to any chain, and
 277          * bound actions should be all removed after flushing. However,
 278          * filters are destroyed in RCU callbacks, we have to hold the chains
 279          * first, otherwise we would always race with RCU callbacks on this list
 280          * without proper locking.
 281          */
 282
 283         /* Wait for existing RCU callbacks to cool down. */
 284         rcu_barrier();
 285
 286         /* Hold a refcnt for all chains, except 0, in case they are gone. */
 287         list_for_each_entry(chain, &block->chain_list, list)
 288                 if (chain->index)
 289                         tcf_chain_hold(chain);
 290
 291         /* No race on the list, because no chain could be destroyed. */
 292         list_for_each_entry(chain, &block->chain_list, list)
 293                 tcf_chain_flush(chain);
 294
 295         /* Wait for RCU callbacks to release the reference count. */
 296         rcu_barrier();
 297
 298         /* At this point, all the chains should have refcnt == 1. */
 299         list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
 300                 tcf_chain_put(chain);
 301         kfree(block);
 302 }
 303 EXPORT_SYMBOL(tcf_block_put);
 304
 305 /* Main classifier routine: scans classifier chain attached
 306  * to this qdisc, (optionally) tests for protocol and asks
 307  * specific classifiers.
 308  */
 309 int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 310                  struct tcf_result *res, bool compat_mode)
 311 {
 312         __be16 protocol = tc_skb_protocol(skb);
 313 #ifdef CONFIG_NET_CLS_ACT
 314         const int max_reclassify_loop = 4;
 315         const struct tcf_proto *orig_tp = tp;
 316         const struct tcf_proto *first_tp;
 317         int limit = 0;
 318
 319 reclassify:
 320 #endif
 321         for (; tp; tp = rcu_dereference_bh(tp->next)) {
 322                 int err;
 323
 324                 if (tp->protocol != protocol &&
 325                     tp->protocol != htons(ETH_P_ALL))
 326                         continue;
 327
 328                 err = tp->classify(skb, tp, res);
 329 #ifdef CONFIG_NET_CLS_ACT
 330                 if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
 331                         first_tp = orig_tp;
 332                         goto reset;
 333                 } else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
 334                         first_tp = res->goto_tp;
 335                         goto reset;
 336                 }
 337 #endif
 338                 if (err >= 0)
 339                         return err;
 340         }
 341
 342         return TC_ACT_UNSPEC; /* signal: continue lookup */
 343 #ifdef CONFIG_NET_CLS_ACT
 344 reset:
 345         if (unlikely(limit++ >= max_reclassify_loop)) {
 346                 net_notice_ratelimited("%s: reclassify loop, rule prio %u, protocol %02x\n",
 347                                        tp->q->ops->id, tp->prio & 0xffff,
 348                                        ntohs(tp->protocol));
 349                 return TC_ACT_SHOT;
 350         }
 351
 352         tp = first_tp;
 353         protocol = tc_skb_protocol(skb);
 354         goto reclassify;
 355 #endif
 356 }
 357 EXPORT_SYMBOL(tcf_classify);
 358
 359 struct tcf_chain_info {
 360         struct tcf_proto __rcu **pprev;
 361         struct tcf_proto __rcu *next;
 362 };
 363
 364 static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
 365 {
 366         return rtnl_dereference(*chain_info->pprev);
 367 }
 368
 369 static void tcf_chain_tp_insert(struct tcf_chain *chain,
 370                                 struct tcf_chain_info *chain_info,
 371                                 struct tcf_proto *tp)
 372 {
 373         if (chain->p_filter_chain &&
 374             *chain_info->pprev == chain->filter_chain)
 375                 rcu_assign_pointer(*chain->p_filter_chain, tp);
 376         RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
 377         rcu_assign_pointer(*chain_info->pprev, tp);
 378         tcf_chain_hold(chain);
 379 }
 380
 381 static void tcf_chain_tp_remove(struct tcf_chain *chain,
 382                                 struct tcf_chain_info *chain_info,
 383                                 struct tcf_proto *tp)
 384 {
 385         struct tcf_proto *next = rtnl_dereference(chain_info->next);
 386
 387         if (chain->p_filter_chain && tp == chain->filter_chain)
 388                 RCU_INIT_POINTER(*chain->p_filter_chain, next);
 389         RCU_INIT_POINTER(*chain_info->pprev, next);
 390         tcf_chain_put(chain);
 391 }
 392
 393 static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
 394                                            struct tcf_chain_info *chain_info,
 395                                            u32 protocol, u32 prio,
 396                                            bool prio_allocate)
 397 {
 398         struct tcf_proto **pprev;
 399         struct tcf_proto *tp;
 400
 401         /* Check the chain for existence of proto-tcf with this priority */
 402         for (pprev = &chain->filter_chain;
 403              (tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
 404                 if (tp->prio >= prio) {
 405                         if (tp->prio == prio) {
 406                                 if (prio_allocate ||
 407                                     (tp->protocol != protocol && protocol))
 408                                         return ERR_PTR(-EINVAL);
 409                         } else {
 410                                 tp = NULL;
 411                         }
 412                         break;
 413                 }
 414         }
 415         chain_info->pprev = pprev;
 416         chain_info->next = tp ? tp->next : NULL;
 417         return tp;
 418 }
 419
 420 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
 421                          struct tcf_proto *tp, void *fh, u32 portid,
 422                          u32 seq, u16 flags, int event)
 423 {
 424         struct tcmsg *tcm;
 425         struct nlmsghdr  *nlh;
 426         unsigned char *b = skb_tail_pointer(skb);
 427
 428         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 429         if (!nlh)
 430                 goto out_nlmsg_trim;
 431         tcm = nlmsg_data(nlh);
 432         tcm->tcm_family = AF_UNSPEC;
 433         tcm->tcm__pad1 = 0;
 434         tcm->tcm__pad2 = 0;
 435         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 436         tcm->tcm_parent = tp->classid;
 437         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 438         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 439                 goto nla_put_failure;
 440         if (nla_put_u32(skb, TCA_CHAIN, tp->chain->index))
 441                 goto nla_put_failure;
 442         if (!fh) {
 443                 tcm->tcm_handle = 0;
 444         } else {
 445                 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
 446                         goto nla_put_failure;
 447         }
 448         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 449         return skb->len;
 450
 451 out_nlmsg_trim:
 452 nla_put_failure:
 453         nlmsg_trim(skb, b);
 454         return -1;
 455 }
 456
 457 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 458                           struct nlmsghdr *n, struct tcf_proto *tp,
 459                           void *fh, int event, bool unicast)
 460 {
 461         struct sk_buff *skb;
 462         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 463
 464         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 465         if (!skb)
 466                 return -ENOBUFS;
 467
 468         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq,
 469                           n->nlmsg_flags, event) <= 0) {
 470                 kfree_skb(skb);
 471                 return -EINVAL;
 472         }
 473
 474         if (unicast)
 475                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
 476
 477         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 478                               n->nlmsg_flags & NLM_F_ECHO);
 479 }
 480
 481 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 482                               struct nlmsghdr *n, struct tcf_proto *tp,
 483                               void *fh, bool unicast, bool *last)
 484 {
 485         struct sk_buff *skb;
 486         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 487         int err;
 488
 489         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 490         if (!skb)
 491                 return -ENOBUFS;
 492
 493         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq,
 494                           n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
 495                 kfree_skb(skb);
 496                 return -EINVAL;
 497         }
 498
 499         err = tp->ops->delete(tp, fh, last);
 500         if (err) {
 501                 kfree_skb(skb);
 502                 return err;
 503         }
 504
 505         if (unicast)
 506                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
 507
 508         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 509                               n->nlmsg_flags & NLM_F_ECHO);
 510 }
 511
 512 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
 513                                  struct nlmsghdr *n,
 514                                  struct tcf_chain *chain, int event)
 515 {
 516         struct tcf_proto *tp;
 517
 518         for (tp = rtnl_dereference(chain->filter_chain);
 519              tp; tp = rtnl_dereference(tp->next))
 520                 tfilter_notify(net, oskb, n, tp, 0, event, false);
 521 }
 522
 523 /* Add/change/delete/get a filter node */
 524
 525 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 526                           struct netlink_ext_ack *extack)
 527 {
 528         struct net *net = sock_net(skb->sk);
 529         struct nlattr *tca[TCA_MAX + 1];
 530         struct tcmsg *t;
 531         u32 protocol;
 532         u32 prio;
 533         bool prio_allocate;
 534         u32 parent;
 535         u32 chain_index;
 536         struct net_device *dev;
 537         struct Qdisc  *q;
 538         struct tcf_chain_info chain_info;
 539         struct tcf_chain *chain = NULL;
 540         struct tcf_block *block;
 541         struct tcf_proto *tp;
 542         const struct Qdisc_class_ops *cops;
 543         unsigned long cl;
 544         void *fh;
 545         int err;
 546         int tp_created;
 547
 548         if ((n->nlmsg_type != RTM_GETTFILTER) &&
 549             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 550                 return -EPERM;
 551
 552 replay:
 553         tp_created = 0;
 554
 555         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
 556         if (err < 0)
 557                 return err;
 558
 559         t = nlmsg_data(n);
 560         protocol = TC_H_MIN(t->tcm_info);
 561         prio = TC_H_MAJ(t->tcm_info);
 562         prio_allocate = false;
 563         parent = t->tcm_parent;
 564         cl = 0;
 565
 566         if (prio == 0) {
 567                 switch (n->nlmsg_type) {
 568                 case RTM_DELTFILTER:
 569                         if (protocol || t->tcm_handle || tca[TCA_KIND])
 570                                 return -ENOENT;
 571                         break;
 572                 case RTM_NEWTFILTER:
 573                         /* If no priority is provided by the user,
 574                          * we allocate one.
 575                          */
 576                         if (n->nlmsg_flags & NLM_F_CREATE) {
 577                                 prio = TC_H_MAKE(0x80000000U, 0U);
 578                                 prio_allocate = true;
 579                                 break;
 580                         }
 581                         /* fall-through */
 582                 default:
 583                         return -ENOENT;
 584                 }
 585         }
 586
 587         /* Find head of filter chain. */
 588
 589         /* Find link */
 590         dev = __dev_get_by_index(net, t->tcm_ifindex);
 591         if (dev == NULL)
 592                 return -ENODEV;
 593
 594         /* Find qdisc */
 595         if (!parent) {
 596                 q = dev->qdisc;
 597                 parent = q->handle;
 598         } else {
 599                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 600                 if (q == NULL)
 601                         return -EINVAL;
 602         }
 603
 604         /* Is it classful? */
 605         cops = q->ops->cl_ops;
 606         if (!cops)
 607                 return -EINVAL;
 608
 609         if (!cops->tcf_block)
 610                 return -EOPNOTSUPP;
 611
 612         /* Do we search for filter, attached to class? */
 613         if (TC_H_MIN(parent)) {
 614                 cl = cops->find(q, parent);
 615                 if (cl == 0)
 616                         return -ENOENT;
 617         }
 618
 619         /* And the last stroke */
 620         block = cops->tcf_block(q, cl);
 621         if (!block) {
 622                 err = -EINVAL;
 623                 goto errout;
 624         }
 625
 626         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
 627         if (chain_index > TC_ACT_EXT_VAL_MASK) {
 628                 err = -EINVAL;
 629                 goto errout;
 630         }
 631         chain = tcf_chain_get(block, chain_index,
 632                               n->nlmsg_type == RTM_NEWTFILTER);
 633         if (!chain) {
 634                 err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;
 635                 goto errout;
 636         }
 637
 638         if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
 639                 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
 640                 tcf_chain_flush(chain);
 641                 err = 0;
 642                 goto errout;
 643         }
 644
 645         tp = tcf_chain_tp_find(chain, &chain_info, protocol,
 646                                prio, prio_allocate);
 647         if (IS_ERR(tp)) {
 648                 err = PTR_ERR(tp);
 649                 goto errout;
 650         }
 651
 652         if (tp == NULL) {
 653                 /* Proto-tcf does not exist, create new one */
 654
 655                 if (tca[TCA_KIND] == NULL || !protocol) {
 656                         err = -EINVAL;
 657                         goto errout;
 658                 }
 659
 660                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 661                     !(n->nlmsg_flags & NLM_F_CREATE)) {
 662                         err = -ENOENT;
 663                         goto errout;
 664                 }
 665
 666                 if (prio_allocate)
 667                         prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));
 668
 669                 tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
 670                                       protocol, prio, parent, q, chain);
 671                 if (IS_ERR(tp)) {
 672                         err = PTR_ERR(tp);
 673                         goto errout;
 674                 }
 675                 tp_created = 1;
 676         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
 677                 err = -EINVAL;
 678                 goto errout;
 679         }
 680
 681         fh = tp->ops->get(tp, t->tcm_handle);
 682
 683         if (!fh) {
 684                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 685                         tcf_chain_tp_remove(chain, &chain_info, tp);
 686                         tfilter_notify(net, skb, n, tp, fh,
 687                                        RTM_DELTFILTER, false);
 688                         tcf_proto_destroy(tp);
 689                         err = 0;
 690                         goto errout;
 691                 }
 692
 693                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 694                     !(n->nlmsg_flags & NLM_F_CREATE)) {
 695                         err = -ENOENT;
 696                         goto errout;
 697                 }
 698         } else {
 699                 bool last;
 700
 701                 switch (n->nlmsg_type) {
 702                 case RTM_NEWTFILTER:
 703                         if (n->nlmsg_flags & NLM_F_EXCL) {
 704                                 if (tp_created)
 705                                         tcf_proto_destroy(tp);
 706                                 err = -EEXIST;
 707                                 goto errout;
 708                         }
 709                         break;
 710                 case RTM_DELTFILTER:
 711                         err = tfilter_del_notify(net, skb, n, tp, fh, false,
 712                                                  &last);
 713                         if (err)
 714                                 goto errout;
 715                         if (last) {
 716                                 tcf_chain_tp_remove(chain, &chain_info, tp);
 717                                 tcf_proto_destroy(tp);
 718                         }
 719                         goto errout;
 720                 case RTM_GETTFILTER:
 721                         err = tfilter_notify(net, skb, n, tp, fh,
 722                                              RTM_NEWTFILTER, true);
 723                         goto errout;
 724                 default:
 725                         err = -EINVAL;
 726                         goto errout;
 727                 }
 728         }
 729
 730         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
 731                               n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
 732         if (err == 0) {
 733                 if (tp_created)
 734                         tcf_chain_tp_insert(chain, &chain_info, tp);
 735                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER, false);
 736         } else {
 737                 if (tp_created)
 738                         tcf_proto_destroy(tp);
 739         }
 740
 741 errout:
 742         if (chain)
 743                 tcf_chain_put(chain);
 744         if (err == -EAGAIN)
 745                 /* Replay the request. */
 746                 goto replay;
 747         return err;
 748 }
 749
 750 struct tcf_dump_args {
 751         struct tcf_walker w;
 752         struct sk_buff *skb;
 753         struct netlink_callback *cb;
 754 };
 755
 756 static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 757 {
 758         struct tcf_dump_args *a = (void *)arg;
 759         struct net *net = sock_net(a->skb->sk);
 760
 761         return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
 762                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
 763                              RTM_NEWTFILTER);
 764 }
 765
 766 static bool tcf_chain_dump(struct tcf_chain *chain, struct sk_buff *skb,
 767                            struct netlink_callback *cb,
 768                            long index_start, long *p_index)
 769 {
 770         struct net *net = sock_net(skb->sk);
 771         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 772         struct tcf_dump_args arg;
 773         struct tcf_proto *tp;
 774
 775         for (tp = rtnl_dereference(chain->filter_chain);
 776              tp; tp = rtnl_dereference(tp->next), (*p_index)++) {
 777                 if (*p_index < index_start)
 778                         continue;
 779                 if (TC_H_MAJ(tcm->tcm_info) &&
 780                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 781                         continue;
 782                 if (TC_H_MIN(tcm->tcm_info) &&
 783                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 784                         continue;
 785                 if (*p_index > index_start)
 786                         memset(&cb->args[1], 0,
 787                                sizeof(cb->args) - sizeof(cb->args[0]));
 788                 if (cb->args[1] == 0) {
 789                         if (tcf_fill_node(net, skb, tp, 0,
 790                                           NETLINK_CB(cb->skb).portid,
 791                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 792                                           RTM_NEWTFILTER) <= 0)
 793                                 return false;
 794
 795                         cb->args[1] = 1;
 796                 }
 797                 if (!tp->ops->walk)
 798                         continue;
 799                 arg.w.fn = tcf_node_dump;
 800                 arg.skb = skb;
 801                 arg.cb = cb;
 802                 arg.w.stop = 0;
 803                 arg.w.skip = cb->args[1] - 1;
 804                 arg.w.count = 0;
 805                 tp->ops->walk(tp, &arg.w);
 806                 cb->args[1] = arg.w.count + 1;
 807                 if (arg.w.stop)
 808                         return false;
 809         }
 810         return true;
 811 }
 812
 813 /* called with RTNL */
 814 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 815 {
 816         struct net *net = sock_net(skb->sk);
 817         struct nlattr *tca[TCA_MAX + 1];
 818         struct net_device *dev;
 819         struct Qdisc *q;
 820         struct tcf_block *block;
 821         struct tcf_chain *chain;
 822         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 823         unsigned long cl = 0;
 824         const struct Qdisc_class_ops *cops;
 825         long index_start;
 826         long index;
 827         int err;
 828
 829         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
 830                 return skb->len;
 831
 832         err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL);
 833         if (err)
 834                 return err;
 835
 836         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
 837         if (!dev)
 838                 return skb->len;
 839
 840         if (!tcm->tcm_parent)
 841                 q = dev->qdisc;
 842         else
 843                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 844         if (!q)
 845                 goto out;
 846         cops = q->ops->cl_ops;
 847         if (!cops)
 848                 goto out;
 849         if (!cops->tcf_block)
 850                 goto out;
 851         if (TC_H_MIN(tcm->tcm_parent)) {
 852                 cl = cops->find(q, tcm->tcm_parent);
 853                 if (cl == 0)
 854                         goto out;
 855         }
 856         block = cops->tcf_block(q, cl);
 857         if (!block)
 858                 goto out;
 859
 860         index_start = cb->args[0];
 861         index = 0;
 862
 863         list_for_each_entry(chain, &block->chain_list, list) {
 864                 if (tca[TCA_CHAIN] &&
 865                     nla_get_u32(tca[TCA_CHAIN]) != chain->index)
 866                         continue;
 867                 if (!tcf_chain_dump(chain, skb, cb, index_start, &index))
 868                         break;
 869         }
 870
 871         cb->args[0] = index;
 872
 873 out:
 874         return skb->len;
 875 }
 876
 877 void tcf_exts_destroy(struct tcf_exts *exts)
 878 {
 879 #ifdef CONFIG_NET_CLS_ACT
 880         LIST_HEAD(actions);
 881
 882         tcf_exts_to_list(exts, &actions);
 883         tcf_action_destroy(&actions, TCA_ACT_UNBIND);
 884         kfree(exts->actions);
 885         exts->nr_actions = 0;
 886 #endif
 887 }
 888 EXPORT_SYMBOL(tcf_exts_destroy);
 889
 890 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 891                       struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
 892 {
 893 #ifdef CONFIG_NET_CLS_ACT
 894         {
 895                 struct tc_action *act;
 896
 897                 if (exts->police && tb[exts->police]) {
 898                         act = tcf_action_init_1(net, tp, tb[exts->police],
 899                                                 rate_tlv, "police", ovr,
 900                                                 TCA_ACT_BIND);
 901                         if (IS_ERR(act))
 902                                 return PTR_ERR(act);
 903
 904                         act->type = exts->type = TCA_OLD_COMPAT;
 905                         exts->actions[0] = act;
 906                         exts->nr_actions = 1;
 907                 } else if (exts->action && tb[exts->action]) {
 908                         LIST_HEAD(actions);
 909                         int err, i = 0;
 910
 911                         err = tcf_action_init(net, tp, tb[exts->action],
 912                                               rate_tlv, NULL, ovr, TCA_ACT_BIND,
 913                                               &actions);
 914                         if (err)
 915                                 return err;
 916                         list_for_each_entry(act, &actions, list)
 917                                 exts->actions[i++] = act;
 918                         exts->nr_actions = i;
 919                 }
 920         }
 921 #else
 922         if ((exts->action && tb[exts->action]) ||
 923             (exts->police && tb[exts->police]))
 924                 return -EOPNOTSUPP;
 925 #endif
 926
 927         return 0;
 928 }
 929 EXPORT_SYMBOL(tcf_exts_validate);
 930
 931 void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src)
 932 {
 933 #ifdef CONFIG_NET_CLS_ACT
 934         struct tcf_exts old = *dst;
 935
 936         *dst = *src;
 937         tcf_exts_destroy(&old);
 938 #endif
 939 }
 940 EXPORT_SYMBOL(tcf_exts_change);
 941
 942 #ifdef CONFIG_NET_CLS_ACT
 943 static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts)
 944 {
 945         if (exts->nr_actions == 0)
 946                 return NULL;
 947         else
 948                 return exts->actions[0];
 949 }
 950 #endif
 951
 952 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 953 {
 954 #ifdef CONFIG_NET_CLS_ACT
 955         struct nlattr *nest;
 956
 957         if (exts->action && tcf_exts_has_actions(exts)) {
 958                 /*
 959                  * again for backward compatible mode - we want
 960                  * to work with both old and new modes of entering
 961                  * tc data even if iproute2  was newer - jhs
 962                  */
 963                 if (exts->type != TCA_OLD_COMPAT) {
 964                         LIST_HEAD(actions);
 965
 966                         nest = nla_nest_start(skb, exts->action);
 967                         if (nest == NULL)
 968                                 goto nla_put_failure;
 969
 970                         tcf_exts_to_list(exts, &actions);
 971                         if (tcf_action_dump(skb, &actions, 0, 0) < 0)
 972                                 goto nla_put_failure;
 973                         nla_nest_end(skb, nest);
 974                 } else if (exts->police) {
 975                         struct tc_action *act = tcf_exts_first_act(exts);
 976                         nest = nla_nest_start(skb, exts->police);
 977                         if (nest == NULL || !act)
 978                                 goto nla_put_failure;
 979                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
 980                                 goto nla_put_failure;
 981                         nla_nest_end(skb, nest);
 982                 }
 983         }
 984         return 0;
 985
 986 nla_put_failure:
 987         nla_nest_cancel(skb, nest);
 988         return -1;
 989 #else
 990         return 0;
 991 #endif
 992 }
 993 EXPORT_SYMBOL(tcf_exts_dump);
 994
 995
 996 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
 997 {
 998 #ifdef CONFIG_NET_CLS_ACT
 999         struct tc_action *a = tcf_exts_first_act(exts);
1000         if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
1001                 return -1;
1002 #endif
1003         return 0;
1004 }
1005 EXPORT_SYMBOL(tcf_exts_dump_stats);
1006
1007 int tcf_exts_get_dev(struct net_device *dev, struct tcf_exts *exts,
1008                      struct net_device **hw_dev)
1009 {
1010 #ifdef CONFIG_NET_CLS_ACT
1011         const struct tc_action *a;
1012         LIST_HEAD(actions);
1013
1014         if (!tcf_exts_has_actions(exts))
1015                 return -EINVAL;
1016
1017         tcf_exts_to_list(exts, &actions);
1018         list_for_each_entry(a, &actions, list) {
1019                 if (a->ops->get_dev) {
1020                         a->ops->get_dev(a, dev_net(dev), hw_dev);
1021                         break;
1022                 }
1023         }
1024         if (*hw_dev)
1025                 return 0;
1026 #endif
1027         return -EOPNOTSUPP;
1028 }
1029 EXPORT_SYMBOL(tcf_exts_get_dev);
1030
1031 static int __init tc_filter_init(void)
1032 {
1033         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);
1034         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);
1035         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
1036                       tc_dump_tfilter, 0);
1037
1038         return 0;
1039 }
1040
1041 subsys_initcall(tc_filter_init);