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