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 static struct workqueue_struct *tc_filter_wq;
  81
  82 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  83 {
  84         struct tcf_proto_ops *t;
  85         int rc = -ENOENT;
  86
  87         /* Wait for outstanding call_rcu()s, if any, from a
  88          * tcf_proto_ops's destroy() handler.
  89          */
  90         rcu_barrier();
  91         flush_workqueue(tc_filter_wq);
  92
  93         write_lock(&cls_mod_lock);
  94         list_for_each_entry(t, &tcf_proto_base, head) {
  95                 if (t == ops) {
  96                         list_del(&t->head);
  97                         rc = 0;
  98                         break;
  99                 }
 100         }
 101         write_unlock(&cls_mod_lock);
 102         return rc;
 103 }
 104 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 105
 106 bool tcf_queue_work(struct work_struct *work)
 107 {
 108         return queue_work(tc_filter_wq, work);
 109 }
 110 EXPORT_SYMBOL(tcf_queue_work);
 111
 112 /* Select new prio value from the range, managed by kernel. */
 113
 114 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 115 {
 116         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 117
 118         if (tp)
 119                 first = tp->prio - 1;
 120
 121         return TC_H_MAJ(first);
 122 }
 123
 124 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
 125                                           u32 prio, u32 parent, struct Qdisc *q,
 126                                           struct tcf_chain *chain)
 127 {
 128         struct tcf_proto *tp;
 129         int err;
 130
 131         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 132         if (!tp)
 133                 return ERR_PTR(-ENOBUFS);
 134
 135         err = -ENOENT;
 136         tp->ops = tcf_proto_lookup_ops(kind);
 137         if (!tp->ops) {
 138 #ifdef CONFIG_MODULES
 139                 rtnl_unlock();
 140                 request_module("cls_%s", kind);
 141                 rtnl_lock();
 142                 tp->ops = tcf_proto_lookup_ops(kind);
 143                 /* We dropped the RTNL semaphore in order to perform
 144                  * the module load. So, even if we succeeded in loading
 145                  * the module we have to replay the request. We indicate
 146                  * this using -EAGAIN.
 147                  */
 148                 if (tp->ops) {
 149                         module_put(tp->ops->owner);
 150                         err = -EAGAIN;
 151                 } else {
 152                         err = -ENOENT;
 153                 }
 154                 goto errout;
 155 #endif
 156         }
 157         tp->classify = tp->ops->classify;
 158         tp->protocol = protocol;
 159         tp->prio = prio;
 160         tp->classid = parent;
 161         tp->q = q;
 162         tp->chain = chain;
 163
 164         err = tp->ops->init(tp);
 165         if (err) {
 166                 module_put(tp->ops->owner);
 167                 goto errout;
 168         }
 169         return tp;
 170
 171 errout:
 172         kfree(tp);
 173         return ERR_PTR(err);
 174 }
 175
 176 static void tcf_proto_destroy(struct tcf_proto *tp)
 177 {
 178         tp->ops->destroy(tp);
 179         module_put(tp->ops->owner);
 180         kfree_rcu(tp, rcu);
 181 }
 182
 183 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 184                                           u32 chain_index)
 185 {
 186         struct tcf_chain *chain;
 187
 188         chain = kzalloc(sizeof(*chain), GFP_KERNEL);
 189         if (!chain)
 190                 return NULL;
 191         list_add_tail(&chain->list, &block->chain_list);
 192         chain->block = block;
 193         chain->index = chain_index;
 194         chain->refcnt = 1;
 195         return chain;
 196 }
 197
 198 static void tcf_chain_flush(struct tcf_chain *chain)
 199 {
 200         struct tcf_proto *tp;
 201
 202         if (chain->p_filter_chain)
 203                 RCU_INIT_POINTER(*chain->p_filter_chain, NULL);
 204         while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) {
 205                 RCU_INIT_POINTER(chain->filter_chain, tp->next);
 206                 tcf_chain_put(chain);
 207                 tcf_proto_destroy(tp);
 208         }
 209 }
 210
 211 static void tcf_chain_destroy(struct tcf_chain *chain)
 212 {
 213         list_del(&chain->list);
 214         kfree(chain);
 215 }
 216
 217 static void tcf_chain_hold(struct tcf_chain *chain)
 218 {
 219         ++chain->refcnt;
 220 }
 221
 222 struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
 223                                 bool create)
 224 {
 225         struct tcf_chain *chain;
 226
 227         list_for_each_entry(chain, &block->chain_list, list) {
 228                 if (chain->index == chain_index) {
 229                         tcf_chain_hold(chain);
 230                         return chain;
 231                 }
 232         }
 233
 234         return create ? tcf_chain_create(block, chain_index) : NULL;
 235 }
 236 EXPORT_SYMBOL(tcf_chain_get);
 237
 238 void tcf_chain_put(struct tcf_chain *chain)
 239 {
 240         if (--chain->refcnt == 0)
 241                 tcf_chain_destroy(chain);
 242 }
 243 EXPORT_SYMBOL(tcf_chain_put);
 244
 245 static void
 246 tcf_chain_filter_chain_ptr_set(struct tcf_chain *chain,
 247                                struct tcf_proto __rcu **p_filter_chain)
 248 {
 249         chain->p_filter_chain = p_filter_chain;
 250 }
 251
 252 int tcf_block_get(struct tcf_block **p_block,
 253                   struct tcf_proto __rcu **p_filter_chain)
 254 {
 255         struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
 256         struct tcf_chain *chain;
 257         int err;
 258
 259         if (!block)
 260                 return -ENOMEM;
 261         INIT_LIST_HEAD(&block->chain_list);
 262         /* Create chain 0 by default, it has to be always present. */
 263         chain = tcf_chain_create(block, 0);
 264         if (!chain) {
 265                 err = -ENOMEM;
 266                 goto err_chain_create;
 267         }
 268         tcf_chain_filter_chain_ptr_set(chain, p_filter_chain);
 269         *p_block = block;
 270         return 0;
 271
 272 err_chain_create:
 273         kfree(block);
 274         return err;
 275 }
 276 EXPORT_SYMBOL(tcf_block_get);
 277
 278 static void tcf_block_put_final(struct work_struct *work)
 279 {
 280         struct tcf_block *block = container_of(work, struct tcf_block, work);
 281         struct tcf_chain *chain, *tmp;
 282
 283         /* At this point, all the chains should have refcnt == 1. */
 284         rtnl_lock();
 285         list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
 286                 tcf_chain_put(chain);
 287         rtnl_unlock();
 288         kfree(block);
 289 }
 290
 291 /* XXX: Standalone actions are not allowed to jump to any chain, and bound
 292  * actions should be all removed after flushing. However, filters are destroyed
 293  * in RCU callbacks, we have to hold the chains first, otherwise we would
 294  * always race with RCU callbacks on this list without proper locking.
 295  */
 296 static void tcf_block_put_deferred(struct work_struct *work)
 297 {
 298         struct tcf_block *block = container_of(work, struct tcf_block, work);
 299         struct tcf_chain *chain;
 300
 301         rtnl_lock();
 302         /* Hold a refcnt for all chains, except 0, in case they are gone. */
 303         list_for_each_entry(chain, &block->chain_list, list)
 304                 if (chain->index)
 305                         tcf_chain_hold(chain);
 306
 307         /* No race on the list, because no chain could be destroyed. */
 308         list_for_each_entry(chain, &block->chain_list, list)
 309                 tcf_chain_flush(chain);
 310
 311         INIT_WORK(&block->work, tcf_block_put_final);
 312         /* Wait for RCU callbacks to release the reference count and make
 313          * sure their works have been queued before this.
 314          */
 315         rcu_barrier();
 316         tcf_queue_work(&block->work);
 317         rtnl_unlock();
 318 }
 319
 320 void tcf_block_put(struct tcf_block *block)
 321 {
 322         if (!block)
 323                 return;
 324
 325         INIT_WORK(&block->work, tcf_block_put_deferred);
 326         /* Wait for existing RCU callbacks to cool down, make sure their works
 327          * have been queued before this. We can not flush pending works here
 328          * because we are holding the RTNL lock.
 329          */
 330         rcu_barrier();
 331         tcf_queue_work(&block->work);
 332 }
 333 EXPORT_SYMBOL(tcf_block_put);
 334
 335 /* Main classifier routine: scans classifier chain attached
 336  * to this qdisc, (optionally) tests for protocol and asks
 337  * specific classifiers.
 338  */
 339 int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 340                  struct tcf_result *res, bool compat_mode)
 341 {
 342         __be16 protocol = tc_skb_protocol(skb);
 343 #ifdef CONFIG_NET_CLS_ACT
 344         const int max_reclassify_loop = 4;
 345         const struct tcf_proto *orig_tp = tp;
 346         const struct tcf_proto *first_tp;
 347         int limit = 0;
 348
 349 reclassify:
 350 #endif
 351         for (; tp; tp = rcu_dereference_bh(tp->next)) {
 352                 int err;
 353
 354                 if (tp->protocol != protocol &&
 355                     tp->protocol != htons(ETH_P_ALL))
 356                         continue;
 357
 358                 err = tp->classify(skb, tp, res);
 359 #ifdef CONFIG_NET_CLS_ACT
 360                 if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
 361                         first_tp = orig_tp;
 362                         goto reset;
 363                 } else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
 364                         first_tp = res->goto_tp;
 365                         goto reset;
 366                 }
 367 #endif
 368                 if (err >= 0)
 369                         return err;
 370         }
 371
 372         return TC_ACT_UNSPEC; /* signal: continue lookup */
 373 #ifdef CONFIG_NET_CLS_ACT
 374 reset:
 375         if (unlikely(limit++ >= max_reclassify_loop)) {
 376                 net_notice_ratelimited("%s: reclassify loop, rule prio %u, protocol %02x\n",
 377                                        tp->q->ops->id, tp->prio & 0xffff,
 378                                        ntohs(tp->protocol));
 379                 return TC_ACT_SHOT;
 380         }
 381
 382         tp = first_tp;
 383         protocol = tc_skb_protocol(skb);
 384         goto reclassify;
 385 #endif
 386 }
 387 EXPORT_SYMBOL(tcf_classify);
 388
 389 struct tcf_chain_info {
 390         struct tcf_proto __rcu **pprev;
 391         struct tcf_proto __rcu *next;
 392 };
 393
 394 static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
 395 {
 396         return rtnl_dereference(*chain_info->pprev);
 397 }
 398
 399 static void tcf_chain_tp_insert(struct tcf_chain *chain,
 400                                 struct tcf_chain_info *chain_info,
 401                                 struct tcf_proto *tp)
 402 {
 403         if (chain->p_filter_chain &&
 404             *chain_info->pprev == chain->filter_chain)
 405                 rcu_assign_pointer(*chain->p_filter_chain, tp);
 406         RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
 407         rcu_assign_pointer(*chain_info->pprev, tp);
 408         tcf_chain_hold(chain);
 409 }
 410
 411 static void tcf_chain_tp_remove(struct tcf_chain *chain,
 412                                 struct tcf_chain_info *chain_info,
 413                                 struct tcf_proto *tp)
 414 {
 415         struct tcf_proto *next = rtnl_dereference(chain_info->next);
 416
 417         if (chain->p_filter_chain && tp == chain->filter_chain)
 418                 RCU_INIT_POINTER(*chain->p_filter_chain, next);
 419         RCU_INIT_POINTER(*chain_info->pprev, next);
 420         tcf_chain_put(chain);
 421 }
 422
 423 static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
 424                                            struct tcf_chain_info *chain_info,
 425                                            u32 protocol, u32 prio,
 426                                            bool prio_allocate)
 427 {
 428         struct tcf_proto **pprev;
 429         struct tcf_proto *tp;
 430
 431         /* Check the chain for existence of proto-tcf with this priority */
 432         for (pprev = &chain->filter_chain;
 433              (tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
 434                 if (tp->prio >= prio) {
 435                         if (tp->prio == prio) {
 436                                 if (prio_allocate ||
 437                                     (tp->protocol != protocol && protocol))
 438                                         return ERR_PTR(-EINVAL);
 439                         } else {
 440                                 tp = NULL;
 441                         }
 442                         break;
 443                 }
 444         }
 445         chain_info->pprev = pprev;
 446         chain_info->next = tp ? tp->next : NULL;
 447         return tp;
 448 }
 449
 450 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
 451                          struct tcf_proto *tp, void *fh, u32 portid,
 452                          u32 seq, u16 flags, int event)
 453 {
 454         struct tcmsg *tcm;
 455         struct nlmsghdr  *nlh;
 456         unsigned char *b = skb_tail_pointer(skb);
 457
 458         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 459         if (!nlh)
 460                 goto out_nlmsg_trim;
 461         tcm = nlmsg_data(nlh);
 462         tcm->tcm_family = AF_UNSPEC;
 463         tcm->tcm__pad1 = 0;
 464         tcm->tcm__pad2 = 0;
 465         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 466         tcm->tcm_parent = tp->classid;
 467         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 468         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 469                 goto nla_put_failure;
 470         if (nla_put_u32(skb, TCA_CHAIN, tp->chain->index))
 471                 goto nla_put_failure;
 472         if (!fh) {
 473                 tcm->tcm_handle = 0;
 474         } else {
 475                 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
 476                         goto nla_put_failure;
 477         }
 478         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 479         return skb->len;
 480
 481 out_nlmsg_trim:
 482 nla_put_failure:
 483         nlmsg_trim(skb, b);
 484         return -1;
 485 }
 486
 487 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 488                           struct nlmsghdr *n, struct tcf_proto *tp,
 489                           void *fh, int event, bool unicast)
 490 {
 491         struct sk_buff *skb;
 492         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 493
 494         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 495         if (!skb)
 496                 return -ENOBUFS;
 497
 498         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq,
 499                           n->nlmsg_flags, event) <= 0) {
 500                 kfree_skb(skb);
 501                 return -EINVAL;
 502         }
 503
 504         if (unicast)
 505                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
 506
 507         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 508                               n->nlmsg_flags & NLM_F_ECHO);
 509 }
 510
 511 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 512                               struct nlmsghdr *n, struct tcf_proto *tp,
 513                               void *fh, bool unicast, bool *last)
 514 {
 515         struct sk_buff *skb;
 516         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 517         int err;
 518
 519         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 520         if (!skb)
 521                 return -ENOBUFS;
 522
 523         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq,
 524                           n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
 525                 kfree_skb(skb);
 526                 return -EINVAL;
 527         }
 528
 529         err = tp->ops->delete(tp, fh, last);
 530         if (err) {
 531                 kfree_skb(skb);
 532                 return err;
 533         }
 534
 535         if (unicast)
 536                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
 537
 538         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 539                               n->nlmsg_flags & NLM_F_ECHO);
 540 }
 541
 542 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
 543                                  struct nlmsghdr *n,
 544                                  struct tcf_chain *chain, int event)
 545 {
 546         struct tcf_proto *tp;
 547
 548         for (tp = rtnl_dereference(chain->filter_chain);
 549              tp; tp = rtnl_dereference(tp->next))
 550                 tfilter_notify(net, oskb, n, tp, 0, event, false);
 551 }
 552
 553 /* Add/change/delete/get a filter node */
 554
 555 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 556                           struct netlink_ext_ack *extack)
 557 {
 558         struct net *net = sock_net(skb->sk);
 559         struct nlattr *tca[TCA_MAX + 1];
 560         struct tcmsg *t;
 561         u32 protocol;
 562         u32 prio;
 563         bool prio_allocate;
 564         u32 parent;
 565         u32 chain_index;
 566         struct net_device *dev;
 567         struct Qdisc  *q;
 568         struct tcf_chain_info chain_info;
 569         struct tcf_chain *chain = NULL;
 570         struct tcf_block *block;
 571         struct tcf_proto *tp;
 572         const struct Qdisc_class_ops *cops;
 573         unsigned long cl;
 574         void *fh;
 575         int err;
 576         int tp_created;
 577
 578         if ((n->nlmsg_type != RTM_GETTFILTER) &&
 579             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 580                 return -EPERM;
 581
 582 replay:
 583         tp_created = 0;
 584
 585         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
 586         if (err < 0)
 587                 return err;
 588
 589         t = nlmsg_data(n);
 590         protocol = TC_H_MIN(t->tcm_info);
 591         prio = TC_H_MAJ(t->tcm_info);
 592         prio_allocate = false;
 593         parent = t->tcm_parent;
 594         cl = 0;
 595
 596         if (prio == 0) {
 597                 switch (n->nlmsg_type) {
 598                 case RTM_DELTFILTER:
 599                         if (protocol || t->tcm_handle || tca[TCA_KIND])
 600                                 return -ENOENT;
 601                         break;
 602                 case RTM_NEWTFILTER:
 603                         /* If no priority is provided by the user,
 604                          * we allocate one.
 605                          */
 606                         if (n->nlmsg_flags & NLM_F_CREATE) {
 607                                 prio = TC_H_MAKE(0x80000000U, 0U);
 608                                 prio_allocate = true;
 609                                 break;
 610                         }
 611                         /* fall-through */
 612                 default:
 613                         return -ENOENT;
 614                 }
 615         }
 616
 617         /* Find head of filter chain. */
 618
 619         /* Find link */
 620         dev = __dev_get_by_index(net, t->tcm_ifindex);
 621         if (dev == NULL)
 622                 return -ENODEV;
 623
 624         /* Find qdisc */
 625         if (!parent) {
 626                 q = dev->qdisc;
 627                 parent = q->handle;
 628         } else {
 629                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 630                 if (q == NULL)
 631                         return -EINVAL;
 632         }
 633
 634         /* Is it classful? */
 635         cops = q->ops->cl_ops;
 636         if (!cops)
 637                 return -EINVAL;
 638
 639         if (!cops->tcf_block)
 640                 return -EOPNOTSUPP;
 641
 642         /* Do we search for filter, attached to class? */
 643         if (TC_H_MIN(parent)) {
 644                 cl = cops->find(q, parent);
 645                 if (cl == 0)
 646                         return -ENOENT;
 647         }
 648
 649         /* And the last stroke */
 650         block = cops->tcf_block(q, cl);
 651         if (!block) {
 652                 err = -EINVAL;
 653                 goto errout;
 654         }
 655
 656         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
 657         if (chain_index > TC_ACT_EXT_VAL_MASK) {
 658                 err = -EINVAL;
 659                 goto errout;
 660         }
 661         chain = tcf_chain_get(block, chain_index,
 662                               n->nlmsg_type == RTM_NEWTFILTER);
 663         if (!chain) {
 664                 err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;
 665                 goto errout;
 666         }
 667
 668         if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
 669                 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
 670                 tcf_chain_flush(chain);
 671                 err = 0;
 672                 goto errout;
 673         }
 674
 675         tp = tcf_chain_tp_find(chain, &chain_info, protocol,
 676                                prio, prio_allocate);
 677         if (IS_ERR(tp)) {
 678                 err = PTR_ERR(tp);
 679                 goto errout;
 680         }
 681
 682         if (tp == NULL) {
 683                 /* Proto-tcf does not exist, create new one */
 684
 685                 if (tca[TCA_KIND] == NULL || !protocol) {
 686                         err = -EINVAL;
 687                         goto errout;
 688                 }
 689
 690                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 691                     !(n->nlmsg_flags & NLM_F_CREATE)) {
 692                         err = -ENOENT;
 693                         goto errout;
 694                 }
 695
 696                 if (prio_allocate)
 697                         prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));
 698
 699                 tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
 700                                       protocol, prio, parent, q, chain);
 701                 if (IS_ERR(tp)) {
 702                         err = PTR_ERR(tp);
 703                         goto errout;
 704                 }
 705                 tp_created = 1;
 706         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
 707                 err = -EINVAL;
 708                 goto errout;
 709         }
 710
 711         fh = tp->ops->get(tp, t->tcm_handle);
 712
 713         if (!fh) {
 714                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 715                         tcf_chain_tp_remove(chain, &chain_info, tp);
 716                         tfilter_notify(net, skb, n, tp, fh,
 717                                        RTM_DELTFILTER, false);
 718                         tcf_proto_destroy(tp);
 719                         err = 0;
 720                         goto errout;
 721                 }
 722
 723                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 724                     !(n->nlmsg_flags & NLM_F_CREATE)) {
 725                         err = -ENOENT;
 726                         goto errout;
 727                 }
 728         } else {
 729                 bool last;
 730
 731                 switch (n->nlmsg_type) {
 732                 case RTM_NEWTFILTER:
 733                         if (n->nlmsg_flags & NLM_F_EXCL) {
 734                                 if (tp_created)
 735                                         tcf_proto_destroy(tp);
 736                                 err = -EEXIST;
 737                                 goto errout;
 738                         }
 739                         break;
 740                 case RTM_DELTFILTER:
 741                         err = tfilter_del_notify(net, skb, n, tp, fh, false,
 742                                                  &last);
 743                         if (err)
 744                                 goto errout;
 745                         if (last) {
 746                                 tcf_chain_tp_remove(chain, &chain_info, tp);
 747                                 tcf_proto_destroy(tp);
 748                         }
 749                         goto errout;
 750                 case RTM_GETTFILTER:
 751                         err = tfilter_notify(net, skb, n, tp, fh,
 752                                              RTM_NEWTFILTER, true);
 753                         goto errout;
 754                 default:
 755                         err = -EINVAL;
 756                         goto errout;
 757                 }
 758         }
 759
 760         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
 761                               n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
 762         if (err == 0) {
 763                 if (tp_created)
 764                         tcf_chain_tp_insert(chain, &chain_info, tp);
 765                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER, false);
 766         } else {
 767                 if (tp_created)
 768                         tcf_proto_destroy(tp);
 769         }
 770
 771 errout:
 772         if (chain)
 773                 tcf_chain_put(chain);
 774         if (err == -EAGAIN)
 775                 /* Replay the request. */
 776                 goto replay;
 777         return err;
 778 }
 779
 780 struct tcf_dump_args {
 781         struct tcf_walker w;
 782         struct sk_buff *skb;
 783         struct netlink_callback *cb;
 784 };
 785
 786 static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 787 {
 788         struct tcf_dump_args *a = (void *)arg;
 789         struct net *net = sock_net(a->skb->sk);
 790
 791         return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
 792                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
 793                              RTM_NEWTFILTER);
 794 }
 795
 796 static bool tcf_chain_dump(struct tcf_chain *chain, struct sk_buff *skb,
 797                            struct netlink_callback *cb,
 798                            long index_start, long *p_index)
 799 {
 800         struct net *net = sock_net(skb->sk);
 801         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 802         struct tcf_dump_args arg;
 803         struct tcf_proto *tp;
 804
 805         for (tp = rtnl_dereference(chain->filter_chain);
 806              tp; tp = rtnl_dereference(tp->next), (*p_index)++) {
 807                 if (*p_index < index_start)
 808                         continue;
 809                 if (TC_H_MAJ(tcm->tcm_info) &&
 810                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 811                         continue;
 812                 if (TC_H_MIN(tcm->tcm_info) &&
 813                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 814                         continue;
 815                 if (*p_index > index_start)
 816                         memset(&cb->args[1], 0,
 817                                sizeof(cb->args) - sizeof(cb->args[0]));
 818                 if (cb->args[1] == 0) {
 819                         if (tcf_fill_node(net, skb, tp, 0,
 820                                           NETLINK_CB(cb->skb).portid,
 821                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 822                                           RTM_NEWTFILTER) <= 0)
 823                                 return false;
 824
 825                         cb->args[1] = 1;
 826                 }
 827                 if (!tp->ops->walk)
 828                         continue;
 829                 arg.w.fn = tcf_node_dump;
 830                 arg.skb = skb;
 831                 arg.cb = cb;
 832                 arg.w.stop = 0;
 833                 arg.w.skip = cb->args[1] - 1;
 834                 arg.w.count = 0;
 835                 tp->ops->walk(tp, &arg.w);
 836                 cb->args[1] = arg.w.count + 1;
 837                 if (arg.w.stop)
 838                         return false;
 839         }
 840         return true;
 841 }
 842
 843 /* called with RTNL */
 844 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 845 {
 846         struct net *net = sock_net(skb->sk);
 847         struct nlattr *tca[TCA_MAX + 1];
 848         struct net_device *dev;
 849         struct Qdisc *q;
 850         struct tcf_block *block;
 851         struct tcf_chain *chain;
 852         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 853         unsigned long cl = 0;
 854         const struct Qdisc_class_ops *cops;
 855         long index_start;
 856         long index;
 857         int err;
 858
 859         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
 860                 return skb->len;
 861
 862         err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL);
 863         if (err)
 864                 return err;
 865
 866         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
 867         if (!dev)
 868                 return skb->len;
 869
 870         if (!tcm->tcm_parent)
 871                 q = dev->qdisc;
 872         else
 873                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 874         if (!q)
 875                 goto out;
 876         cops = q->ops->cl_ops;
 877         if (!cops)
 878                 goto out;
 879         if (!cops->tcf_block)
 880                 goto out;
 881         if (TC_H_MIN(tcm->tcm_parent)) {
 882                 cl = cops->find(q, tcm->tcm_parent);
 883                 if (cl == 0)
 884                         goto out;
 885         }
 886         block = cops->tcf_block(q, cl);
 887         if (!block)
 888                 goto out;
 889
 890         index_start = cb->args[0];
 891         index = 0;
 892
 893         list_for_each_entry(chain, &block->chain_list, list) {
 894                 if (tca[TCA_CHAIN] &&
 895                     nla_get_u32(tca[TCA_CHAIN]) != chain->index)
 896                         continue;
 897                 if (!tcf_chain_dump(chain, skb, cb, index_start, &index))
 898                         break;
 899         }
 900
 901         cb->args[0] = index;
 902
 903 out:
 904         return skb->len;
 905 }
 906
 907 void tcf_exts_destroy(struct tcf_exts *exts)
 908 {
 909 #ifdef CONFIG_NET_CLS_ACT
 910         LIST_HEAD(actions);
 911
 912         ASSERT_RTNL();
 913         tcf_exts_to_list(exts, &actions);
 914         tcf_action_destroy(&actions, TCA_ACT_UNBIND);
 915         kfree(exts->actions);
 916         exts->nr_actions = 0;
 917 #endif
 918 }
 919 EXPORT_SYMBOL(tcf_exts_destroy);
 920
 921 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 922                       struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
 923 {
 924 #ifdef CONFIG_NET_CLS_ACT
 925         {
 926                 struct tc_action *act;
 927
 928                 if (exts->police && tb[exts->police]) {
 929                         act = tcf_action_init_1(net, tp, tb[exts->police],
 930                                                 rate_tlv, "police", ovr,
 931                                                 TCA_ACT_BIND);
 932                         if (IS_ERR(act))
 933                                 return PTR_ERR(act);
 934
 935                         act->type = exts->type = TCA_OLD_COMPAT;
 936                         exts->actions[0] = act;
 937                         exts->nr_actions = 1;
 938                 } else if (exts->action && tb[exts->action]) {
 939                         LIST_HEAD(actions);
 940                         int err, i = 0;
 941
 942                         err = tcf_action_init(net, tp, tb[exts->action],
 943                                               rate_tlv, NULL, ovr, TCA_ACT_BIND,
 944                                               &actions);
 945                         if (err)
 946                                 return err;
 947                         list_for_each_entry(act, &actions, list)
 948                                 exts->actions[i++] = act;
 949                         exts->nr_actions = i;
 950                 }
 951         }
 952 #else
 953         if ((exts->action && tb[exts->action]) ||
 954             (exts->police && tb[exts->police]))
 955                 return -EOPNOTSUPP;
 956 #endif
 957
 958         return 0;
 959 }
 960 EXPORT_SYMBOL(tcf_exts_validate);
 961
 962 void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src)
 963 {
 964 #ifdef CONFIG_NET_CLS_ACT
 965         struct tcf_exts old = *dst;
 966
 967         *dst = *src;
 968         tcf_exts_destroy(&old);
 969 #endif
 970 }
 971 EXPORT_SYMBOL(tcf_exts_change);
 972
 973 #ifdef CONFIG_NET_CLS_ACT
 974 static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts)
 975 {
 976         if (exts->nr_actions == 0)
 977                 return NULL;
 978         else
 979                 return exts->actions[0];
 980 }
 981 #endif
 982
 983 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 984 {
 985 #ifdef CONFIG_NET_CLS_ACT
 986         struct nlattr *nest;
 987
 988         if (exts->action && tcf_exts_has_actions(exts)) {
 989                 /*
 990                  * again for backward compatible mode - we want
 991                  * to work with both old and new modes of entering
 992                  * tc data even if iproute2  was newer - jhs
 993                  */
 994                 if (exts->type != TCA_OLD_COMPAT) {
 995                         LIST_HEAD(actions);
 996
 997                         nest = nla_nest_start(skb, exts->action);
 998                         if (nest == NULL)
 999                                 goto nla_put_failure;
1000
1001                         tcf_exts_to_list(exts, &actions);
1002                         if (tcf_action_dump(skb, &actions, 0, 0) < 0)
1003                                 goto nla_put_failure;
1004                         nla_nest_end(skb, nest);
1005                 } else if (exts->police) {
1006                         struct tc_action *act = tcf_exts_first_act(exts);
1007                         nest = nla_nest_start(skb, exts->police);
1008                         if (nest == NULL || !act)
1009                                 goto nla_put_failure;
1010                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
1011                                 goto nla_put_failure;
1012                         nla_nest_end(skb, nest);
1013                 }
1014         }
1015         return 0;
1016
1017 nla_put_failure:
1018         nla_nest_cancel(skb, nest);
1019         return -1;
1020 #else
1021         return 0;
1022 #endif
1023 }
1024 EXPORT_SYMBOL(tcf_exts_dump);
1025
1026
1027 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
1028 {
1029 #ifdef CONFIG_NET_CLS_ACT
1030         struct tc_action *a = tcf_exts_first_act(exts);
1031         if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
1032                 return -1;
1033 #endif
1034         return 0;
1035 }
1036 EXPORT_SYMBOL(tcf_exts_dump_stats);
1037
1038 int tcf_exts_get_dev(struct net_device *dev, struct tcf_exts *exts,
1039                      struct net_device **hw_dev)
1040 {
1041 #ifdef CONFIG_NET_CLS_ACT
1042         const struct tc_action *a;
1043         LIST_HEAD(actions);
1044
1045         if (!tcf_exts_has_actions(exts))
1046                 return -EINVAL;
1047
1048         tcf_exts_to_list(exts, &actions);
1049         list_for_each_entry(a, &actions, list) {
1050                 if (a->ops->get_dev) {
1051                         a->ops->get_dev(a, dev_net(dev), hw_dev);
1052                         break;
1053                 }
1054         }
1055         if (*hw_dev)
1056                 return 0;
1057 #endif
1058         return -EOPNOTSUPP;
1059 }
1060 EXPORT_SYMBOL(tcf_exts_get_dev);
1061
1062 static int __init tc_filter_init(void)
1063 {
1064         tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
1065         if (!tc_filter_wq)
1066                 return -ENOMEM;
1067
1068         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);
1069         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);
1070         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
1071                       tc_dump_tfilter, 0);
1072
1073         return 0;
1074 }
1075
1076 subsys_initcall(tc_filter_init);