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TOMOYO Linux Cross Reference
Linux/net/sched/cls_api.c

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  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/slab.h>
 27 #include <linux/idr.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 extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1];
 35 
 36 /* The list of all installed classifier types */
 37 static LIST_HEAD(tcf_proto_base);
 38 
 39 /* Protects list of registered TC modules. It is pure SMP lock. */
 40 static DEFINE_RWLOCK(cls_mod_lock);
 41 
 42 /* Find classifier type by string name */
 43 
 44 static const struct tcf_proto_ops *__tcf_proto_lookup_ops(const char *kind)
 45 {
 46         const struct tcf_proto_ops *t, *res = NULL;
 47 
 48         if (kind) {
 49                 read_lock(&cls_mod_lock);
 50                 list_for_each_entry(t, &tcf_proto_base, head) {
 51                         if (strcmp(kind, t->kind) == 0) {
 52                                 if (try_module_get(t->owner))
 53                                         res = t;
 54                                 break;
 55                         }
 56                 }
 57                 read_unlock(&cls_mod_lock);
 58         }
 59         return res;
 60 }
 61 
 62 static const struct tcf_proto_ops *
 63 tcf_proto_lookup_ops(const char *kind, struct netlink_ext_ack *extack)
 64 {
 65         const struct tcf_proto_ops *ops;
 66 
 67         ops = __tcf_proto_lookup_ops(kind);
 68         if (ops)
 69                 return ops;
 70 #ifdef CONFIG_MODULES
 71         rtnl_unlock();
 72         request_module("cls_%s", kind);
 73         rtnl_lock();
 74         ops = __tcf_proto_lookup_ops(kind);
 75         /* We dropped the RTNL semaphore in order to perform
 76          * the module load. So, even if we succeeded in loading
 77          * the module we have to replay the request. We indicate
 78          * this using -EAGAIN.
 79          */
 80         if (ops) {
 81                 module_put(ops->owner);
 82                 return ERR_PTR(-EAGAIN);
 83         }
 84 #endif
 85         NL_SET_ERR_MSG(extack, "TC classifier not found");
 86         return ERR_PTR(-ENOENT);
 87 }
 88 
 89 /* Register(unregister) new classifier type */
 90 
 91 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
 92 {
 93         struct tcf_proto_ops *t;
 94         int rc = -EEXIST;
 95 
 96         write_lock(&cls_mod_lock);
 97         list_for_each_entry(t, &tcf_proto_base, head)
 98                 if (!strcmp(ops->kind, t->kind))
 99                         goto out;
100 
101         list_add_tail(&ops->head, &tcf_proto_base);
102         rc = 0;
103 out:
104         write_unlock(&cls_mod_lock);
105         return rc;
106 }
107 EXPORT_SYMBOL(register_tcf_proto_ops);
108 
109 static struct workqueue_struct *tc_filter_wq;
110 
111 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
112 {
113         struct tcf_proto_ops *t;
114         int rc = -ENOENT;
115 
116         /* Wait for outstanding call_rcu()s, if any, from a
117          * tcf_proto_ops's destroy() handler.
118          */
119         rcu_barrier();
120         flush_workqueue(tc_filter_wq);
121 
122         write_lock(&cls_mod_lock);
123         list_for_each_entry(t, &tcf_proto_base, head) {
124                 if (t == ops) {
125                         list_del(&t->head);
126                         rc = 0;
127                         break;
128                 }
129         }
130         write_unlock(&cls_mod_lock);
131         return rc;
132 }
133 EXPORT_SYMBOL(unregister_tcf_proto_ops);
134 
135 bool tcf_queue_work(struct rcu_work *rwork, work_func_t func)
136 {
137         INIT_RCU_WORK(rwork, func);
138         return queue_rcu_work(tc_filter_wq, rwork);
139 }
140 EXPORT_SYMBOL(tcf_queue_work);
141 
142 /* Select new prio value from the range, managed by kernel. */
143 
144 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
145 {
146         u32 first = TC_H_MAKE(0xC0000000U, 0U);
147 
148         if (tp)
149                 first = tp->prio - 1;
150 
151         return TC_H_MAJ(first);
152 }
153 
154 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
155                                           u32 prio, struct tcf_chain *chain,
156                                           struct netlink_ext_ack *extack)
157 {
158         struct tcf_proto *tp;
159         int err;
160 
161         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
162         if (!tp)
163                 return ERR_PTR(-ENOBUFS);
164 
165         tp->ops = tcf_proto_lookup_ops(kind, extack);
166         if (IS_ERR(tp->ops)) {
167                 err = PTR_ERR(tp->ops);
168                 goto errout;
169         }
170         tp->classify = tp->ops->classify;
171         tp->protocol = protocol;
172         tp->prio = prio;
173         tp->chain = chain;
174 
175         err = tp->ops->init(tp);
176         if (err) {
177                 module_put(tp->ops->owner);
178                 goto errout;
179         }
180         return tp;
181 
182 errout:
183         kfree(tp);
184         return ERR_PTR(err);
185 }
186 
187 static void tcf_proto_destroy(struct tcf_proto *tp,
188                               struct netlink_ext_ack *extack)
189 {
190         tp->ops->destroy(tp, extack);
191         module_put(tp->ops->owner);
192         kfree_rcu(tp, rcu);
193 }
194 
195 struct tcf_filter_chain_list_item {
196         struct list_head list;
197         tcf_chain_head_change_t *chain_head_change;
198         void *chain_head_change_priv;
199 };
200 
201 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
202                                           u32 chain_index)
203 {
204         struct tcf_chain *chain;
205 
206         chain = kzalloc(sizeof(*chain), GFP_KERNEL);
207         if (!chain)
208                 return NULL;
209         list_add_tail(&chain->list, &block->chain_list);
210         chain->block = block;
211         chain->index = chain_index;
212         chain->refcnt = 1;
213         if (!chain->index)
214                 block->chain0.chain = chain;
215         return chain;
216 }
217 
218 static void tcf_chain_head_change_item(struct tcf_filter_chain_list_item *item,
219                                        struct tcf_proto *tp_head)
220 {
221         if (item->chain_head_change)
222                 item->chain_head_change(tp_head, item->chain_head_change_priv);
223 }
224 
225 static void tcf_chain0_head_change(struct tcf_chain *chain,
226                                    struct tcf_proto *tp_head)
227 {
228         struct tcf_filter_chain_list_item *item;
229         struct tcf_block *block = chain->block;
230 
231         if (chain->index)
232                 return;
233         list_for_each_entry(item, &block->chain0.filter_chain_list, list)
234                 tcf_chain_head_change_item(item, tp_head);
235 }
236 
237 static void tcf_chain_destroy(struct tcf_chain *chain)
238 {
239         struct tcf_block *block = chain->block;
240 
241         list_del(&chain->list);
242         if (!chain->index)
243                 block->chain0.chain = NULL;
244         kfree(chain);
245         if (list_empty(&block->chain_list) && !refcount_read(&block->refcnt))
246                 kfree_rcu(block, rcu);
247 }
248 
249 static void tcf_chain_hold(struct tcf_chain *chain)
250 {
251         ++chain->refcnt;
252 }
253 
254 static bool tcf_chain_held_by_acts_only(struct tcf_chain *chain)
255 {
256         /* In case all the references are action references, this
257          * chain should not be shown to the user.
258          */
259         return chain->refcnt == chain->action_refcnt;
260 }
261 
262 static struct tcf_chain *tcf_chain_lookup(struct tcf_block *block,
263                                           u32 chain_index)
264 {
265         struct tcf_chain *chain;
266 
267         list_for_each_entry(chain, &block->chain_list, list) {
268                 if (chain->index == chain_index)
269                         return chain;
270         }
271         return NULL;
272 }
273 
274 static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
275                            u32 seq, u16 flags, int event, bool unicast);
276 
277 static struct tcf_chain *__tcf_chain_get(struct tcf_block *block,
278                                          u32 chain_index, bool create,
279                                          bool by_act)
280 {
281         struct tcf_chain *chain = tcf_chain_lookup(block, chain_index);
282 
283         if (chain) {
284                 tcf_chain_hold(chain);
285         } else {
286                 if (!create)
287                         return NULL;
288                 chain = tcf_chain_create(block, chain_index);
289                 if (!chain)
290                         return NULL;
291         }
292 
293         if (by_act)
294                 ++chain->action_refcnt;
295 
296         /* Send notification only in case we got the first
297          * non-action reference. Until then, the chain acts only as
298          * a placeholder for actions pointing to it and user ought
299          * not know about them.
300          */
301         if (chain->refcnt - chain->action_refcnt == 1 && !by_act)
302                 tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
303                                 RTM_NEWCHAIN, false);
304 
305         return chain;
306 }
307 
308 static struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
309                                        bool create)
310 {
311         return __tcf_chain_get(block, chain_index, create, false);
312 }
313 
314 struct tcf_chain *tcf_chain_get_by_act(struct tcf_block *block, u32 chain_index)
315 {
316         return __tcf_chain_get(block, chain_index, true, true);
317 }
318 EXPORT_SYMBOL(tcf_chain_get_by_act);
319 
320 static void tc_chain_tmplt_del(struct tcf_chain *chain);
321 
322 static void __tcf_chain_put(struct tcf_chain *chain, bool by_act)
323 {
324         if (by_act)
325                 chain->action_refcnt--;
326         chain->refcnt--;
327 
328         /* The last dropped non-action reference will trigger notification. */
329         if (chain->refcnt - chain->action_refcnt == 0 && !by_act)
330                 tc_chain_notify(chain, NULL, 0, 0, RTM_DELCHAIN, false);
331 
332         if (chain->refcnt == 0) {
333                 tc_chain_tmplt_del(chain);
334                 tcf_chain_destroy(chain);
335         }
336 }
337 
338 static void tcf_chain_put(struct tcf_chain *chain)
339 {
340         __tcf_chain_put(chain, false);
341 }
342 
343 void tcf_chain_put_by_act(struct tcf_chain *chain)
344 {
345         __tcf_chain_put(chain, true);
346 }
347 EXPORT_SYMBOL(tcf_chain_put_by_act);
348 
349 static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
350 {
351         if (chain->explicitly_created)
352                 tcf_chain_put(chain);
353 }
354 
355 static void tcf_chain_flush(struct tcf_chain *chain)
356 {
357         struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);
358 
359         tcf_chain0_head_change(chain, NULL);
360         while (tp) {
361                 RCU_INIT_POINTER(chain->filter_chain, tp->next);
362                 tcf_proto_destroy(tp, NULL);
363                 tp = rtnl_dereference(chain->filter_chain);
364                 tcf_chain_put(chain);
365         }
366 }
367 
368 static bool tcf_block_offload_in_use(struct tcf_block *block)
369 {
370         return block->offloadcnt;
371 }
372 
373 static int tcf_block_offload_cmd(struct tcf_block *block,
374                                  struct net_device *dev,
375                                  struct tcf_block_ext_info *ei,
376                                  enum tc_block_command command,
377                                  struct netlink_ext_ack *extack)
378 {
379         struct tc_block_offload bo = {};
380 
381         bo.command = command;
382         bo.binder_type = ei->binder_type;
383         bo.block = block;
384         bo.extack = extack;
385         return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
386 }
387 
388 static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
389                                   struct tcf_block_ext_info *ei,
390                                   struct netlink_ext_ack *extack)
391 {
392         struct net_device *dev = q->dev_queue->dev;
393         int err;
394 
395         if (!dev->netdev_ops->ndo_setup_tc)
396                 goto no_offload_dev_inc;
397 
398         /* If tc offload feature is disabled and the block we try to bind
399          * to already has some offloaded filters, forbid to bind.
400          */
401         if (!tc_can_offload(dev) && tcf_block_offload_in_use(block)) {
402                 NL_SET_ERR_MSG(extack, "Bind to offloaded block failed as dev has offload disabled");
403                 return -EOPNOTSUPP;
404         }
405 
406         err = tcf_block_offload_cmd(block, dev, ei, TC_BLOCK_BIND, extack);
407         if (err == -EOPNOTSUPP)
408                 goto no_offload_dev_inc;
409         return err;
410 
411 no_offload_dev_inc:
412         if (tcf_block_offload_in_use(block))
413                 return -EOPNOTSUPP;
414         block->nooffloaddevcnt++;
415         return 0;
416 }
417 
418 static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
419                                      struct tcf_block_ext_info *ei)
420 {
421         struct net_device *dev = q->dev_queue->dev;
422         int err;
423 
424         if (!dev->netdev_ops->ndo_setup_tc)
425                 goto no_offload_dev_dec;
426         err = tcf_block_offload_cmd(block, dev, ei, TC_BLOCK_UNBIND, NULL);
427         if (err == -EOPNOTSUPP)
428                 goto no_offload_dev_dec;
429         return;
430 
431 no_offload_dev_dec:
432         WARN_ON(block->nooffloaddevcnt-- == 0);
433 }
434 
435 static int
436 tcf_chain0_head_change_cb_add(struct tcf_block *block,
437                               struct tcf_block_ext_info *ei,
438                               struct netlink_ext_ack *extack)
439 {
440         struct tcf_chain *chain0 = block->chain0.chain;
441         struct tcf_filter_chain_list_item *item;
442 
443         item = kmalloc(sizeof(*item), GFP_KERNEL);
444         if (!item) {
445                 NL_SET_ERR_MSG(extack, "Memory allocation for head change callback item failed");
446                 return -ENOMEM;
447         }
448         item->chain_head_change = ei->chain_head_change;
449         item->chain_head_change_priv = ei->chain_head_change_priv;
450         if (chain0 && chain0->filter_chain)
451                 tcf_chain_head_change_item(item, chain0->filter_chain);
452         list_add(&item->list, &block->chain0.filter_chain_list);
453         return 0;
454 }
455 
456 static void
457 tcf_chain0_head_change_cb_del(struct tcf_block *block,
458                               struct tcf_block_ext_info *ei)
459 {
460         struct tcf_chain *chain0 = block->chain0.chain;
461         struct tcf_filter_chain_list_item *item;
462 
463         list_for_each_entry(item, &block->chain0.filter_chain_list, list) {
464                 if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
465                     (item->chain_head_change == ei->chain_head_change &&
466                      item->chain_head_change_priv == ei->chain_head_change_priv)) {
467                         if (chain0)
468                                 tcf_chain_head_change_item(item, NULL);
469                         list_del(&item->list);
470                         kfree(item);
471                         return;
472                 }
473         }
474         WARN_ON(1);
475 }
476 
477 struct tcf_net {
478         spinlock_t idr_lock; /* Protects idr */
479         struct idr idr;
480 };
481 
482 static unsigned int tcf_net_id;
483 
484 static int tcf_block_insert(struct tcf_block *block, struct net *net,
485                             struct netlink_ext_ack *extack)
486 {
487         struct tcf_net *tn = net_generic(net, tcf_net_id);
488         int err;
489 
490         idr_preload(GFP_KERNEL);
491         spin_lock(&tn->idr_lock);
492         err = idr_alloc_u32(&tn->idr, block, &block->index, block->index,
493                             GFP_NOWAIT);
494         spin_unlock(&tn->idr_lock);
495         idr_preload_end();
496 
497         return err;
498 }
499 
500 static void tcf_block_remove(struct tcf_block *block, struct net *net)
501 {
502         struct tcf_net *tn = net_generic(net, tcf_net_id);
503 
504         spin_lock(&tn->idr_lock);
505         idr_remove(&tn->idr, block->index);
506         spin_unlock(&tn->idr_lock);
507 }
508 
509 static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
510                                           u32 block_index,
511                                           struct netlink_ext_ack *extack)
512 {
513         struct tcf_block *block;
514 
515         block = kzalloc(sizeof(*block), GFP_KERNEL);
516         if (!block) {
517                 NL_SET_ERR_MSG(extack, "Memory allocation for block failed");
518                 return ERR_PTR(-ENOMEM);
519         }
520         INIT_LIST_HEAD(&block->chain_list);
521         INIT_LIST_HEAD(&block->cb_list);
522         INIT_LIST_HEAD(&block->owner_list);
523         INIT_LIST_HEAD(&block->chain0.filter_chain_list);
524 
525         refcount_set(&block->refcnt, 1);
526         block->net = net;
527         block->index = block_index;
528 
529         /* Don't store q pointer for blocks which are shared */
530         if (!tcf_block_shared(block))
531                 block->q = q;
532         return block;
533 }
534 
535 static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index)
536 {
537         struct tcf_net *tn = net_generic(net, tcf_net_id);
538 
539         return idr_find(&tn->idr, block_index);
540 }
541 
542 static struct tcf_block *tcf_block_refcnt_get(struct net *net, u32 block_index)
543 {
544         struct tcf_block *block;
545 
546         rcu_read_lock();
547         block = tcf_block_lookup(net, block_index);
548         if (block && !refcount_inc_not_zero(&block->refcnt))
549                 block = NULL;
550         rcu_read_unlock();
551 
552         return block;
553 }
554 
555 static void tcf_block_flush_all_chains(struct tcf_block *block)
556 {
557         struct tcf_chain *chain;
558 
559         /* Hold a refcnt for all chains, so that they don't disappear
560          * while we are iterating.
561          */
562         list_for_each_entry(chain, &block->chain_list, list)
563                 tcf_chain_hold(chain);
564 
565         list_for_each_entry(chain, &block->chain_list, list)
566                 tcf_chain_flush(chain);
567 }
568 
569 static void tcf_block_put_all_chains(struct tcf_block *block)
570 {
571         struct tcf_chain *chain, *tmp;
572 
573         /* At this point, all the chains should have refcnt >= 1. */
574         list_for_each_entry_safe(chain, tmp, &block->chain_list, list) {
575                 tcf_chain_put_explicitly_created(chain);
576                 tcf_chain_put(chain);
577         }
578 }
579 
580 static void __tcf_block_put(struct tcf_block *block, struct Qdisc *q,
581                             struct tcf_block_ext_info *ei)
582 {
583         if (refcount_dec_and_test(&block->refcnt)) {
584                 /* Flushing/putting all chains will cause the block to be
585                  * deallocated when last chain is freed. However, if chain_list
586                  * is empty, block has to be manually deallocated. After block
587                  * reference counter reached 0, it is no longer possible to
588                  * increment it or add new chains to block.
589                  */
590                 bool free_block = list_empty(&block->chain_list);
591 
592                 if (tcf_block_shared(block))
593                         tcf_block_remove(block, block->net);
594                 if (!free_block)
595                         tcf_block_flush_all_chains(block);
596 
597                 if (q)
598                         tcf_block_offload_unbind(block, q, ei);
599 
600                 if (free_block)
601                         kfree_rcu(block, rcu);
602                 else
603                         tcf_block_put_all_chains(block);
604         } else if (q) {
605                 tcf_block_offload_unbind(block, q, ei);
606         }
607 }
608 
609 static void tcf_block_refcnt_put(struct tcf_block *block)
610 {
611         __tcf_block_put(block, NULL, NULL);
612 }
613 
614 /* Find tcf block.
615  * Set q, parent, cl when appropriate.
616  */
617 
618 static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q,
619                                         u32 *parent, unsigned long *cl,
620                                         int ifindex, u32 block_index,
621                                         struct netlink_ext_ack *extack)
622 {
623         struct tcf_block *block;
624         int err = 0;
625 
626         if (ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
627                 block = tcf_block_refcnt_get(net, block_index);
628                 if (!block) {
629                         NL_SET_ERR_MSG(extack, "Block of given index was not found");
630                         return ERR_PTR(-EINVAL);
631                 }
632         } else {
633                 const struct Qdisc_class_ops *cops;
634                 struct net_device *dev;
635 
636                 rcu_read_lock();
637 
638                 /* Find link */
639                 dev = dev_get_by_index_rcu(net, ifindex);
640                 if (!dev) {
641                         rcu_read_unlock();
642                         return ERR_PTR(-ENODEV);
643                 }
644 
645                 /* Find qdisc */
646                 if (!*parent) {
647                         *q = dev->qdisc;
648                         *parent = (*q)->handle;
649                 } else {
650                         *q = qdisc_lookup_rcu(dev, TC_H_MAJ(*parent));
651                         if (!*q) {
652                                 NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
653                                 err = -EINVAL;
654                                 goto errout_rcu;
655                         }
656                 }
657 
658                 *q = qdisc_refcount_inc_nz(*q);
659                 if (!*q) {
660                         NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
661                         err = -EINVAL;
662                         goto errout_rcu;
663                 }
664 
665                 /* Is it classful? */
666                 cops = (*q)->ops->cl_ops;
667                 if (!cops) {
668                         NL_SET_ERR_MSG(extack, "Qdisc not classful");
669                         err = -EINVAL;
670                         goto errout_rcu;
671                 }
672 
673                 if (!cops->tcf_block) {
674                         NL_SET_ERR_MSG(extack, "Class doesn't support blocks");
675                         err = -EOPNOTSUPP;
676                         goto errout_rcu;
677                 }
678 
679                 /* At this point we know that qdisc is not noop_qdisc,
680                  * which means that qdisc holds a reference to net_device
681                  * and we hold a reference to qdisc, so it is safe to release
682                  * rcu read lock.
683                  */
684                 rcu_read_unlock();
685 
686                 /* Do we search for filter, attached to class? */
687                 if (TC_H_MIN(*parent)) {
688                         *cl = cops->find(*q, *parent);
689                         if (*cl == 0) {
690                                 NL_SET_ERR_MSG(extack, "Specified class doesn't exist");
691                                 err = -ENOENT;
692                                 goto errout_qdisc;
693                         }
694                 }
695 
696                 /* And the last stroke */
697                 block = cops->tcf_block(*q, *cl, extack);
698                 if (!block) {
699                         err = -EINVAL;
700                         goto errout_qdisc;
701                 }
702                 if (tcf_block_shared(block)) {
703                         NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");
704                         err = -EOPNOTSUPP;
705                         goto errout_qdisc;
706                 }
707 
708                 /* Always take reference to block in order to support execution
709                  * of rules update path of cls API without rtnl lock. Caller
710                  * must release block when it is finished using it. 'if' block
711                  * of this conditional obtain reference to block by calling
712                  * tcf_block_refcnt_get().
713                  */
714                 refcount_inc(&block->refcnt);
715         }
716 
717         return block;
718 
719 errout_rcu:
720         rcu_read_unlock();
721 errout_qdisc:
722         if (*q) {
723                 qdisc_put(*q);
724                 *q = NULL;
725         }
726         return ERR_PTR(err);
727 }
728 
729 static void tcf_block_release(struct Qdisc *q, struct tcf_block *block)
730 {
731         if (!IS_ERR_OR_NULL(block))
732                 tcf_block_refcnt_put(block);
733 
734         if (q)
735                 qdisc_put(q);
736 }
737 
738 struct tcf_block_owner_item {
739         struct list_head list;
740         struct Qdisc *q;
741         enum tcf_block_binder_type binder_type;
742 };
743 
744 static void
745 tcf_block_owner_netif_keep_dst(struct tcf_block *block,
746                                struct Qdisc *q,
747                                enum tcf_block_binder_type binder_type)
748 {
749         if (block->keep_dst &&
750             binder_type != TCF_BLOCK_BINDER_TYPE_CLSACT_INGRESS &&
751             binder_type != TCF_BLOCK_BINDER_TYPE_CLSACT_EGRESS)
752                 netif_keep_dst(qdisc_dev(q));
753 }
754 
755 void tcf_block_netif_keep_dst(struct tcf_block *block)
756 {
757         struct tcf_block_owner_item *item;
758 
759         block->keep_dst = true;
760         list_for_each_entry(item, &block->owner_list, list)
761                 tcf_block_owner_netif_keep_dst(block, item->q,
762                                                item->binder_type);
763 }
764 EXPORT_SYMBOL(tcf_block_netif_keep_dst);
765 
766 static int tcf_block_owner_add(struct tcf_block *block,
767                                struct Qdisc *q,
768                                enum tcf_block_binder_type binder_type)
769 {
770         struct tcf_block_owner_item *item;
771 
772         item = kmalloc(sizeof(*item), GFP_KERNEL);
773         if (!item)
774                 return -ENOMEM;
775         item->q = q;
776         item->binder_type = binder_type;
777         list_add(&item->list, &block->owner_list);
778         return 0;
779 }
780 
781 static void tcf_block_owner_del(struct tcf_block *block,
782                                 struct Qdisc *q,
783                                 enum tcf_block_binder_type binder_type)
784 {
785         struct tcf_block_owner_item *item;
786 
787         list_for_each_entry(item, &block->owner_list, list) {
788                 if (item->q == q && item->binder_type == binder_type) {
789                         list_del(&item->list);
790                         kfree(item);
791                         return;
792                 }
793         }
794         WARN_ON(1);
795 }
796 
797 int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
798                       struct tcf_block_ext_info *ei,
799                       struct netlink_ext_ack *extack)
800 {
801         struct net *net = qdisc_net(q);
802         struct tcf_block *block = NULL;
803         int err;
804 
805         if (ei->block_index)
806                 /* block_index not 0 means the shared block is requested */
807                 block = tcf_block_refcnt_get(net, ei->block_index);
808 
809         if (!block) {
810                 block = tcf_block_create(net, q, ei->block_index, extack);
811                 if (IS_ERR(block))
812                         return PTR_ERR(block);
813                 if (tcf_block_shared(block)) {
814                         err = tcf_block_insert(block, net, extack);
815                         if (err)
816                                 goto err_block_insert;
817                 }
818         }
819 
820         err = tcf_block_owner_add(block, q, ei->binder_type);
821         if (err)
822                 goto err_block_owner_add;
823 
824         tcf_block_owner_netif_keep_dst(block, q, ei->binder_type);
825 
826         err = tcf_chain0_head_change_cb_add(block, ei, extack);
827         if (err)
828                 goto err_chain0_head_change_cb_add;
829 
830         err = tcf_block_offload_bind(block, q, ei, extack);
831         if (err)
832                 goto err_block_offload_bind;
833 
834         *p_block = block;
835         return 0;
836 
837 err_block_offload_bind:
838         tcf_chain0_head_change_cb_del(block, ei);
839 err_chain0_head_change_cb_add:
840         tcf_block_owner_del(block, q, ei->binder_type);
841 err_block_owner_add:
842 err_block_insert:
843         tcf_block_refcnt_put(block);
844         return err;
845 }
846 EXPORT_SYMBOL(tcf_block_get_ext);
847 
848 static void tcf_chain_head_change_dflt(struct tcf_proto *tp_head, void *priv)
849 {
850         struct tcf_proto __rcu **p_filter_chain = priv;
851 
852         rcu_assign_pointer(*p_filter_chain, tp_head);
853 }
854 
855 int tcf_block_get(struct tcf_block **p_block,
856                   struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q,
857                   struct netlink_ext_ack *extack)
858 {
859         struct tcf_block_ext_info ei = {
860                 .chain_head_change = tcf_chain_head_change_dflt,
861                 .chain_head_change_priv = p_filter_chain,
862         };
863 
864         WARN_ON(!p_filter_chain);
865         return tcf_block_get_ext(p_block, q, &ei, extack);
866 }
867 EXPORT_SYMBOL(tcf_block_get);
868 
869 /* XXX: Standalone actions are not allowed to jump to any chain, and bound
870  * actions should be all removed after flushing.
871  */
872 void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,
873                        struct tcf_block_ext_info *ei)
874 {
875         if (!block)
876                 return;
877         tcf_chain0_head_change_cb_del(block, ei);
878         tcf_block_owner_del(block, q, ei->binder_type);
879 
880         __tcf_block_put(block, q, ei);
881 }
882 EXPORT_SYMBOL(tcf_block_put_ext);
883 
884 void tcf_block_put(struct tcf_block *block)
885 {
886         struct tcf_block_ext_info ei = {0, };
887 
888         if (!block)
889                 return;
890         tcf_block_put_ext(block, block->q, &ei);
891 }
892 
893 EXPORT_SYMBOL(tcf_block_put);
894 
895 struct tcf_block_cb {
896         struct list_head list;
897         tc_setup_cb_t *cb;
898         void *cb_ident;
899         void *cb_priv;
900         unsigned int refcnt;
901 };
902 
903 void *tcf_block_cb_priv(struct tcf_block_cb *block_cb)
904 {
905         return block_cb->cb_priv;
906 }
907 EXPORT_SYMBOL(tcf_block_cb_priv);
908 
909 struct tcf_block_cb *tcf_block_cb_lookup(struct tcf_block *block,
910                                          tc_setup_cb_t *cb, void *cb_ident)
911 {       struct tcf_block_cb *block_cb;
912 
913         list_for_each_entry(block_cb, &block->cb_list, list)
914                 if (block_cb->cb == cb && block_cb->cb_ident == cb_ident)
915                         return block_cb;
916         return NULL;
917 }
918 EXPORT_SYMBOL(tcf_block_cb_lookup);
919 
920 void tcf_block_cb_incref(struct tcf_block_cb *block_cb)
921 {
922         block_cb->refcnt++;
923 }
924 EXPORT_SYMBOL(tcf_block_cb_incref);
925 
926 unsigned int tcf_block_cb_decref(struct tcf_block_cb *block_cb)
927 {
928         return --block_cb->refcnt;
929 }
930 EXPORT_SYMBOL(tcf_block_cb_decref);
931 
932 static int
933 tcf_block_playback_offloads(struct tcf_block *block, tc_setup_cb_t *cb,
934                             void *cb_priv, bool add, bool offload_in_use,
935                             struct netlink_ext_ack *extack)
936 {
937         struct tcf_chain *chain;
938         struct tcf_proto *tp;
939         int err;
940 
941         list_for_each_entry(chain, &block->chain_list, list) {
942                 for (tp = rtnl_dereference(chain->filter_chain); tp;
943                      tp = rtnl_dereference(tp->next)) {
944                         if (tp->ops->reoffload) {
945                                 err = tp->ops->reoffload(tp, add, cb, cb_priv,
946                                                          extack);
947                                 if (err && add)
948                                         goto err_playback_remove;
949                         } else if (add && offload_in_use) {
950                                 err = -EOPNOTSUPP;
951                                 NL_SET_ERR_MSG(extack, "Filter HW offload failed - classifier without re-offloading support");
952                                 goto err_playback_remove;
953                         }
954                 }
955         }
956 
957         return 0;
958 
959 err_playback_remove:
960         tcf_block_playback_offloads(block, cb, cb_priv, false, offload_in_use,
961                                     extack);
962         return err;
963 }
964 
965 struct tcf_block_cb *__tcf_block_cb_register(struct tcf_block *block,
966                                              tc_setup_cb_t *cb, void *cb_ident,
967                                              void *cb_priv,
968                                              struct netlink_ext_ack *extack)
969 {
970         struct tcf_block_cb *block_cb;
971         int err;
972 
973         /* Replay any already present rules */
974         err = tcf_block_playback_offloads(block, cb, cb_priv, true,
975                                           tcf_block_offload_in_use(block),
976                                           extack);
977         if (err)
978                 return ERR_PTR(err);
979 
980         block_cb = kzalloc(sizeof(*block_cb), GFP_KERNEL);
981         if (!block_cb)
982                 return ERR_PTR(-ENOMEM);
983         block_cb->cb = cb;
984         block_cb->cb_ident = cb_ident;
985         block_cb->cb_priv = cb_priv;
986         list_add(&block_cb->list, &block->cb_list);
987         return block_cb;
988 }
989 EXPORT_SYMBOL(__tcf_block_cb_register);
990 
991 int tcf_block_cb_register(struct tcf_block *block,
992                           tc_setup_cb_t *cb, void *cb_ident,
993                           void *cb_priv, struct netlink_ext_ack *extack)
994 {
995         struct tcf_block_cb *block_cb;
996 
997         block_cb = __tcf_block_cb_register(block, cb, cb_ident, cb_priv,
998                                            extack);
999         return PTR_ERR_OR_ZERO(block_cb);
1000 }
1001 EXPORT_SYMBOL(tcf_block_cb_register);
1002 
1003 void __tcf_block_cb_unregister(struct tcf_block *block,
1004                                struct tcf_block_cb *block_cb)
1005 {
1006         tcf_block_playback_offloads(block, block_cb->cb, block_cb->cb_priv,
1007                                     false, tcf_block_offload_in_use(block),
1008                                     NULL);
1009         list_del(&block_cb->list);
1010         kfree(block_cb);
1011 }
1012 EXPORT_SYMBOL(__tcf_block_cb_unregister);
1013 
1014 void tcf_block_cb_unregister(struct tcf_block *block,
1015                              tc_setup_cb_t *cb, void *cb_ident)
1016 {
1017         struct tcf_block_cb *block_cb;
1018 
1019         block_cb = tcf_block_cb_lookup(block, cb, cb_ident);
1020         if (!block_cb)
1021                 return;
1022         __tcf_block_cb_unregister(block, block_cb);
1023 }
1024 EXPORT_SYMBOL(tcf_block_cb_unregister);
1025 
1026 static int tcf_block_cb_call(struct tcf_block *block, enum tc_setup_type type,
1027                              void *type_data, bool err_stop)
1028 {
1029         struct tcf_block_cb *block_cb;
1030         int ok_count = 0;
1031         int err;
1032 
1033         /* Make sure all netdevs sharing this block are offload-capable. */
1034         if (block->nooffloaddevcnt && err_stop)
1035                 return -EOPNOTSUPP;
1036 
1037         list_for_each_entry(block_cb, &block->cb_list, list) {
1038                 err = block_cb->cb(type, type_data, block_cb->cb_priv);
1039                 if (err) {
1040                         if (err_stop)
1041                                 return err;
1042                 } else {
1043                         ok_count++;
1044                 }
1045         }
1046         return ok_count;
1047 }
1048 
1049 /* Main classifier routine: scans classifier chain attached
1050  * to this qdisc, (optionally) tests for protocol and asks
1051  * specific classifiers.
1052  */
1053 int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
1054                  struct tcf_result *res, bool compat_mode)
1055 {
1056         __be16 protocol = tc_skb_protocol(skb);
1057 #ifdef CONFIG_NET_CLS_ACT
1058         const int max_reclassify_loop = 4;
1059         const struct tcf_proto *orig_tp = tp;
1060         const struct tcf_proto *first_tp;
1061         int limit = 0;
1062 
1063 reclassify:
1064 #endif
1065         for (; tp; tp = rcu_dereference_bh(tp->next)) {
1066                 int err;
1067 
1068                 if (tp->protocol != protocol &&
1069                     tp->protocol != htons(ETH_P_ALL))
1070                         continue;
1071 
1072                 err = tp->classify(skb, tp, res);
1073 #ifdef CONFIG_NET_CLS_ACT
1074                 if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
1075                         first_tp = orig_tp;
1076                         goto reset;
1077                 } else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
1078                         first_tp = res->goto_tp;
1079                         goto reset;
1080                 }
1081 #endif
1082                 if (err >= 0)
1083                         return err;
1084         }
1085 
1086         return TC_ACT_UNSPEC; /* signal: continue lookup */
1087 #ifdef CONFIG_NET_CLS_ACT
1088 reset:
1089         if (unlikely(limit++ >= max_reclassify_loop)) {
1090                 net_notice_ratelimited("%u: reclassify loop, rule prio %u, protocol %02x\n",
1091                                        tp->chain->block->index,
1092                                        tp->prio & 0xffff,
1093                                        ntohs(tp->protocol));
1094                 return TC_ACT_SHOT;
1095         }
1096 
1097         tp = first_tp;
1098         protocol = tc_skb_protocol(skb);
1099         goto reclassify;
1100 #endif
1101 }
1102 EXPORT_SYMBOL(tcf_classify);
1103 
1104 struct tcf_chain_info {
1105         struct tcf_proto __rcu **pprev;
1106         struct tcf_proto __rcu *next;
1107 };
1108 
1109 static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
1110 {
1111         return rtnl_dereference(*chain_info->pprev);
1112 }
1113 
1114 static void tcf_chain_tp_insert(struct tcf_chain *chain,
1115                                 struct tcf_chain_info *chain_info,
1116                                 struct tcf_proto *tp)
1117 {
1118         if (*chain_info->pprev == chain->filter_chain)
1119                 tcf_chain0_head_change(chain, tp);
1120         RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
1121         rcu_assign_pointer(*chain_info->pprev, tp);
1122         tcf_chain_hold(chain);
1123 }
1124 
1125 static void tcf_chain_tp_remove(struct tcf_chain *chain,
1126                                 struct tcf_chain_info *chain_info,
1127                                 struct tcf_proto *tp)
1128 {
1129         struct tcf_proto *next = rtnl_dereference(chain_info->next);
1130 
1131         if (tp == chain->filter_chain)
1132                 tcf_chain0_head_change(chain, next);
1133         RCU_INIT_POINTER(*chain_info->pprev, next);
1134         tcf_chain_put(chain);
1135 }
1136 
1137 static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
1138                                            struct tcf_chain_info *chain_info,
1139                                            u32 protocol, u32 prio,
1140                                            bool prio_allocate)
1141 {
1142         struct tcf_proto **pprev;
1143         struct tcf_proto *tp;
1144 
1145         /* Check the chain for existence of proto-tcf with this priority */
1146         for (pprev = &chain->filter_chain;
1147              (tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
1148                 if (tp->prio >= prio) {
1149                         if (tp->prio == prio) {
1150                                 if (prio_allocate ||
1151                                     (tp->protocol != protocol && protocol))
1152                                         return ERR_PTR(-EINVAL);
1153                         } else {
1154                                 tp = NULL;
1155                         }
1156                         break;
1157                 }
1158         }
1159         chain_info->pprev = pprev;
1160         chain_info->next = tp ? tp->next : NULL;
1161         return tp;
1162 }
1163 
1164 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
1165                          struct tcf_proto *tp, struct tcf_block *block,
1166                          struct Qdisc *q, u32 parent, void *fh,
1167                          u32 portid, u32 seq, u16 flags, int event)
1168 {
1169         struct tcmsg *tcm;
1170         struct nlmsghdr  *nlh;
1171         unsigned char *b = skb_tail_pointer(skb);
1172 
1173         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1174         if (!nlh)
1175                 goto out_nlmsg_trim;
1176         tcm = nlmsg_data(nlh);
1177         tcm->tcm_family = AF_UNSPEC;
1178         tcm->tcm__pad1 = 0;
1179         tcm->tcm__pad2 = 0;
1180         if (q) {
1181                 tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
1182                 tcm->tcm_parent = parent;
1183         } else {
1184                 tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
1185                 tcm->tcm_block_index = block->index;
1186         }
1187         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
1188         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
1189                 goto nla_put_failure;
1190         if (nla_put_u32(skb, TCA_CHAIN, tp->chain->index))
1191                 goto nla_put_failure;
1192         if (!fh) {
1193                 tcm->tcm_handle = 0;
1194         } else {
1195                 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
1196                         goto nla_put_failure;
1197         }
1198         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1199         return skb->len;
1200 
1201 out_nlmsg_trim:
1202 nla_put_failure:
1203         nlmsg_trim(skb, b);
1204         return -1;
1205 }
1206 
1207 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
1208                           struct nlmsghdr *n, struct tcf_proto *tp,
1209                           struct tcf_block *block, struct Qdisc *q,
1210                           u32 parent, void *fh, int event, bool unicast)
1211 {
1212         struct sk_buff *skb;
1213         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1214 
1215         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1216         if (!skb)
1217                 return -ENOBUFS;
1218 
1219         if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
1220                           n->nlmsg_seq, n->nlmsg_flags, event) <= 0) {
1221                 kfree_skb(skb);
1222                 return -EINVAL;
1223         }
1224 
1225         if (unicast)
1226                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
1227 
1228         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1229                               n->nlmsg_flags & NLM_F_ECHO);
1230 }
1231 
1232 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
1233                               struct nlmsghdr *n, struct tcf_proto *tp,
1234                               struct tcf_block *block, struct Qdisc *q,
1235                               u32 parent, void *fh, bool unicast, bool *last,
1236                               struct netlink_ext_ack *extack)
1237 {
1238         struct sk_buff *skb;
1239         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1240         int err;
1241 
1242         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1243         if (!skb)
1244                 return -ENOBUFS;
1245 
1246         if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
1247                           n->nlmsg_seq, n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
1248                 NL_SET_ERR_MSG(extack, "Failed to build del event notification");
1249                 kfree_skb(skb);
1250                 return -EINVAL;
1251         }
1252 
1253         err = tp->ops->delete(tp, fh, last, extack);
1254         if (err) {
1255                 kfree_skb(skb);
1256                 return err;
1257         }
1258 
1259         if (unicast)
1260                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
1261 
1262         err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1263                              n->nlmsg_flags & NLM_F_ECHO);
1264         if (err < 0)
1265                 NL_SET_ERR_MSG(extack, "Failed to send filter delete notification");
1266         return err;
1267 }
1268 
1269 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
1270                                  struct tcf_block *block, struct Qdisc *q,
1271                                  u32 parent, struct nlmsghdr *n,
1272                                  struct tcf_chain *chain, int event)
1273 {
1274         struct tcf_proto *tp;
1275 
1276         for (tp = rtnl_dereference(chain->filter_chain);
1277              tp; tp = rtnl_dereference(tp->next))
1278                 tfilter_notify(net, oskb, n, tp, block,
1279                                q, parent, NULL, event, false);
1280 }
1281 
1282 static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
1283                           struct netlink_ext_ack *extack)
1284 {
1285         struct net *net = sock_net(skb->sk);
1286         struct nlattr *tca[TCA_MAX + 1];
1287         struct tcmsg *t;
1288         u32 protocol;
1289         u32 prio;
1290         bool prio_allocate;
1291         u32 parent;
1292         u32 chain_index;
1293         struct Qdisc *q = NULL;
1294         struct tcf_chain_info chain_info;
1295         struct tcf_chain *chain = NULL;
1296         struct tcf_block *block;
1297         struct tcf_proto *tp;
1298         unsigned long cl;
1299         void *fh;
1300         int err;
1301         int tp_created;
1302 
1303         if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1304                 return -EPERM;
1305 
1306 replay:
1307         tp_created = 0;
1308 
1309         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
1310         if (err < 0)
1311                 return err;
1312 
1313         t = nlmsg_data(n);
1314         protocol = TC_H_MIN(t->tcm_info);
1315         prio = TC_H_MAJ(t->tcm_info);
1316         prio_allocate = false;
1317         parent = t->tcm_parent;
1318         cl = 0;
1319 
1320         if (prio == 0) {
1321                 /* If no priority is provided by the user,
1322                  * we allocate one.
1323                  */
1324                 if (n->nlmsg_flags & NLM_F_CREATE) {
1325                         prio = TC_H_MAKE(0x80000000U, 0U);
1326                         prio_allocate = true;
1327                 } else {
1328                         NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
1329                         return -ENOENT;
1330                 }
1331         }
1332 
1333         /* Find head of filter chain. */
1334 
1335         block = tcf_block_find(net, &q, &parent, &cl,
1336                                t->tcm_ifindex, t->tcm_block_index, extack);
1337         if (IS_ERR(block)) {
1338                 err = PTR_ERR(block);
1339                 goto errout;
1340         }
1341 
1342         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
1343         if (chain_index > TC_ACT_EXT_VAL_MASK) {
1344                 NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
1345                 err = -EINVAL;
1346                 goto errout;
1347         }
1348         chain = tcf_chain_get(block, chain_index, true);
1349         if (!chain) {
1350                 NL_SET_ERR_MSG(extack, "Cannot create specified filter chain");
1351                 err = -ENOMEM;
1352                 goto errout;
1353         }
1354 
1355         tp = tcf_chain_tp_find(chain, &chain_info, protocol,
1356                                prio, prio_allocate);
1357         if (IS_ERR(tp)) {
1358                 NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
1359                 err = PTR_ERR(tp);
1360                 goto errout;
1361         }
1362 
1363         if (tp == NULL) {
1364                 /* Proto-tcf does not exist, create new one */
1365 
1366                 if (tca[TCA_KIND] == NULL || !protocol) {
1367                         NL_SET_ERR_MSG(extack, "Filter kind and protocol must be specified");
1368                         err = -EINVAL;
1369                         goto errout;
1370                 }
1371 
1372                 if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1373                         NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
1374                         err = -ENOENT;
1375                         goto errout;
1376                 }
1377 
1378                 if (prio_allocate)
1379                         prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));
1380 
1381                 tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
1382                                       protocol, prio, chain, extack);
1383                 if (IS_ERR(tp)) {
1384                         err = PTR_ERR(tp);
1385                         goto errout;
1386                 }
1387                 tp_created = 1;
1388         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
1389                 NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
1390                 err = -EINVAL;
1391                 goto errout;
1392         }
1393 
1394         fh = tp->ops->get(tp, t->tcm_handle);
1395 
1396         if (!fh) {
1397                 if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1398                         NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
1399                         err = -ENOENT;
1400                         goto errout;
1401                 }
1402         } else if (n->nlmsg_flags & NLM_F_EXCL) {
1403                 NL_SET_ERR_MSG(extack, "Filter already exists");
1404                 err = -EEXIST;
1405                 goto errout;
1406         }
1407 
1408         if (chain->tmplt_ops && chain->tmplt_ops != tp->ops) {
1409                 NL_SET_ERR_MSG(extack, "Chain template is set to a different filter kind");
1410                 err = -EINVAL;
1411                 goto errout;
1412         }
1413 
1414         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
1415                               n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE,
1416                               extack);
1417         if (err == 0) {
1418                 if (tp_created)
1419                         tcf_chain_tp_insert(chain, &chain_info, tp);
1420                 tfilter_notify(net, skb, n, tp, block, q, parent, fh,
1421                                RTM_NEWTFILTER, false);
1422         } else {
1423                 if (tp_created)
1424                         tcf_proto_destroy(tp, NULL);
1425         }
1426 
1427 errout:
1428         if (chain)
1429                 tcf_chain_put(chain);
1430         tcf_block_release(q, block);
1431         if (err == -EAGAIN)
1432                 /* Replay the request. */
1433                 goto replay;
1434         return err;
1435 }
1436 
1437 static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
1438                           struct netlink_ext_ack *extack)
1439 {
1440         struct net *net = sock_net(skb->sk);
1441         struct nlattr *tca[TCA_MAX + 1];
1442         struct tcmsg *t;
1443         u32 protocol;
1444         u32 prio;
1445         u32 parent;
1446         u32 chain_index;
1447         struct Qdisc *q = NULL;
1448         struct tcf_chain_info chain_info;
1449         struct tcf_chain *chain = NULL;
1450         struct tcf_block *block;
1451         struct tcf_proto *tp = NULL;
1452         unsigned long cl = 0;
1453         void *fh = NULL;
1454         int err;
1455 
1456         if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1457                 return -EPERM;
1458 
1459         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
1460         if (err < 0)
1461                 return err;
1462 
1463         t = nlmsg_data(n);
1464         protocol = TC_H_MIN(t->tcm_info);
1465         prio = TC_H_MAJ(t->tcm_info);
1466         parent = t->tcm_parent;
1467 
1468         if (prio == 0 && (protocol || t->tcm_handle || tca[TCA_KIND])) {
1469                 NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");
1470                 return -ENOENT;
1471         }
1472 
1473         /* Find head of filter chain. */
1474 
1475         block = tcf_block_find(net, &q, &parent, &cl,
1476                                t->tcm_ifindex, t->tcm_block_index, extack);
1477         if (IS_ERR(block)) {
1478                 err = PTR_ERR(block);
1479                 goto errout;
1480         }
1481 
1482         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
1483         if (chain_index > TC_ACT_EXT_VAL_MASK) {
1484                 NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
1485                 err = -EINVAL;
1486                 goto errout;
1487         }
1488         chain = tcf_chain_get(block, chain_index, false);
1489         if (!chain) {
1490                 /* User requested flush on non-existent chain. Nothing to do,
1491                  * so just return success.
1492                  */
1493                 if (prio == 0) {
1494                         err = 0;
1495                         goto errout;
1496                 }
1497                 NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
1498                 err = -ENOENT;
1499                 goto errout;
1500         }
1501 
1502         if (prio == 0) {
1503                 tfilter_notify_chain(net, skb, block, q, parent, n,
1504                                      chain, RTM_DELTFILTER);
1505                 tcf_chain_flush(chain);
1506                 err = 0;
1507                 goto errout;
1508         }
1509 
1510         tp = tcf_chain_tp_find(chain, &chain_info, protocol,
1511                                prio, false);
1512         if (!tp || IS_ERR(tp)) {
1513                 NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
1514                 err = tp ? PTR_ERR(tp) : -ENOENT;
1515                 goto errout;
1516         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
1517                 NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
1518                 err = -EINVAL;
1519                 goto errout;
1520         }
1521 
1522         fh = tp->ops->get(tp, t->tcm_handle);
1523 
1524         if (!fh) {
1525                 if (t->tcm_handle == 0) {
1526                         tcf_chain_tp_remove(chain, &chain_info, tp);
1527                         tfilter_notify(net, skb, n, tp, block, q, parent, fh,
1528                                        RTM_DELTFILTER, false);
1529                         tcf_proto_destroy(tp, extack);
1530                         err = 0;
1531                 } else {
1532                         NL_SET_ERR_MSG(extack, "Specified filter handle not found");
1533                         err = -ENOENT;
1534                 }
1535         } else {
1536                 bool last;
1537 
1538                 err = tfilter_del_notify(net, skb, n, tp, block,
1539                                          q, parent, fh, false, &last,
1540                                          extack);
1541                 if (err)
1542                         goto errout;
1543                 if (last) {
1544                         tcf_chain_tp_remove(chain, &chain_info, tp);
1545                         tcf_proto_destroy(tp, extack);
1546                 }
1547         }
1548 
1549 errout:
1550         if (chain)
1551                 tcf_chain_put(chain);
1552         tcf_block_release(q, block);
1553         return err;
1554 }
1555 
1556 static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
1557                           struct netlink_ext_ack *extack)
1558 {
1559         struct net *net = sock_net(skb->sk);
1560         struct nlattr *tca[TCA_MAX + 1];
1561         struct tcmsg *t;
1562         u32 protocol;
1563         u32 prio;
1564         u32 parent;
1565         u32 chain_index;
1566         struct Qdisc *q = NULL;
1567         struct tcf_chain_info chain_info;
1568         struct tcf_chain *chain = NULL;
1569         struct tcf_block *block;
1570         struct tcf_proto *tp = NULL;
1571         unsigned long cl = 0;
1572         void *fh = NULL;
1573         int err;
1574 
1575         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
1576         if (err < 0)
1577                 return err;
1578 
1579         t = nlmsg_data(n);
1580         protocol = TC_H_MIN(t->tcm_info);
1581         prio = TC_H_MAJ(t->tcm_info);
1582         parent = t->tcm_parent;
1583 
1584         if (prio == 0) {
1585                 NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
1586                 return -ENOENT;
1587         }
1588 
1589         /* Find head of filter chain. */
1590 
1591         block = tcf_block_find(net, &q, &parent, &cl,
1592                                t->tcm_ifindex, t->tcm_block_index, extack);
1593         if (IS_ERR(block)) {
1594                 err = PTR_ERR(block);
1595                 goto errout;
1596         }
1597 
1598         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
1599         if (chain_index > TC_ACT_EXT_VAL_MASK) {
1600                 NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
1601                 err = -EINVAL;
1602                 goto errout;
1603         }
1604         chain = tcf_chain_get(block, chain_index, false);
1605         if (!chain) {
1606                 NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
1607                 err = -EINVAL;
1608                 goto errout;
1609         }
1610 
1611         tp = tcf_chain_tp_find(chain, &chain_info, protocol,
1612                                prio, false);
1613         if (!tp || IS_ERR(tp)) {
1614                 NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
1615                 err = tp ? PTR_ERR(tp) : -ENOENT;
1616                 goto errout;
1617         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
1618                 NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
1619                 err = -EINVAL;
1620                 goto errout;
1621         }
1622 
1623         fh = tp->ops->get(tp, t->tcm_handle);
1624 
1625         if (!fh) {
1626                 NL_SET_ERR_MSG(extack, "Specified filter handle not found");
1627                 err = -ENOENT;
1628         } else {
1629                 err = tfilter_notify(net, skb, n, tp, block, q, parent,
1630                                      fh, RTM_NEWTFILTER, true);
1631                 if (err < 0)
1632                         NL_SET_ERR_MSG(extack, "Failed to send filter notify message");
1633         }
1634 
1635 errout:
1636         if (chain)
1637                 tcf_chain_put(chain);
1638         tcf_block_release(q, block);
1639         return err;
1640 }
1641 
1642 struct tcf_dump_args {
1643         struct tcf_walker w;
1644         struct sk_buff *skb;
1645         struct netlink_callback *cb;
1646         struct tcf_block *block;
1647         struct Qdisc *q;
1648         u32 parent;
1649 };
1650 
1651 static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
1652 {
1653         struct tcf_dump_args *a = (void *)arg;
1654         struct net *net = sock_net(a->skb->sk);
1655 
1656         return tcf_fill_node(net, a->skb, tp, a->block, a->q, a->parent,
1657                              n, NETLINK_CB(a->cb->skb).portid,
1658                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
1659                              RTM_NEWTFILTER);
1660 }
1661 
1662 static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
1663                            struct sk_buff *skb, struct netlink_callback *cb,
1664                            long index_start, long *p_index)
1665 {
1666         struct net *net = sock_net(skb->sk);
1667         struct tcf_block *block = chain->block;
1668         struct tcmsg *tcm = nlmsg_data(cb->nlh);
1669         struct tcf_dump_args arg;
1670         struct tcf_proto *tp;
1671 
1672         for (tp = rtnl_dereference(chain->filter_chain);
1673              tp; tp = rtnl_dereference(tp->next), (*p_index)++) {
1674                 if (*p_index < index_start)
1675                         continue;
1676                 if (TC_H_MAJ(tcm->tcm_info) &&
1677                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
1678                         continue;
1679                 if (TC_H_MIN(tcm->tcm_info) &&
1680                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
1681                         continue;
1682                 if (*p_index > index_start)
1683                         memset(&cb->args[1], 0,
1684                                sizeof(cb->args) - sizeof(cb->args[0]));
1685                 if (cb->args[1] == 0) {
1686                         if (tcf_fill_node(net, skb, tp, block, q, parent, NULL,
1687                                           NETLINK_CB(cb->skb).portid,
1688                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
1689                                           RTM_NEWTFILTER) <= 0)
1690                                 return false;
1691 
1692                         cb->args[1] = 1;
1693                 }
1694                 if (!tp->ops->walk)
1695                         continue;
1696                 arg.w.fn = tcf_node_dump;
1697                 arg.skb = skb;
1698                 arg.cb = cb;
1699                 arg.block = block;
1700                 arg.q = q;
1701                 arg.parent = parent;
1702                 arg.w.stop = 0;
1703                 arg.w.skip = cb->args[1] - 1;
1704                 arg.w.count = 0;
1705                 arg.w.cookie = cb->args[2];
1706                 tp->ops->walk(tp, &arg.w);
1707                 cb->args[2] = arg.w.cookie;
1708                 cb->args[1] = arg.w.count + 1;
1709                 if (arg.w.stop)
1710                         return false;
1711         }
1712         return true;
1713 }
1714 
1715 /* called with RTNL */
1716 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
1717 {
1718         struct net *net = sock_net(skb->sk);
1719         struct nlattr *tca[TCA_MAX + 1];
1720         struct Qdisc *q = NULL;
1721         struct tcf_block *block;
1722         struct tcf_chain *chain;
1723         struct tcmsg *tcm = nlmsg_data(cb->nlh);
1724         long index_start;
1725         long index;
1726         u32 parent;
1727         int err;
1728 
1729         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
1730                 return skb->len;
1731 
1732         err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL,
1733                           cb->extack);
1734         if (err)
1735                 return err;
1736 
1737         if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
1738                 block = tcf_block_refcnt_get(net, tcm->tcm_block_index);
1739                 if (!block)
1740                         goto out;
1741                 /* If we work with block index, q is NULL and parent value
1742                  * will never be used in the following code. The check
1743                  * in tcf_fill_node prevents it. However, compiler does not
1744                  * see that far, so set parent to zero to silence the warning
1745                  * about parent being uninitialized.
1746                  */
1747                 parent = 0;
1748         } else {
1749                 const struct Qdisc_class_ops *cops;
1750                 struct net_device *dev;
1751                 unsigned long cl = 0;
1752 
1753                 dev = __dev_get_by_index(net, tcm->tcm_ifindex);
1754                 if (!dev)
1755                         return skb->len;
1756 
1757                 parent = tcm->tcm_parent;
1758                 if (!parent) {
1759                         q = dev->qdisc;
1760                         parent = q->handle;
1761                 } else {
1762                         q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
1763                 }
1764                 if (!q)
1765                         goto out;
1766                 cops = q->ops->cl_ops;
1767                 if (!cops)
1768                         goto out;
1769                 if (!cops->tcf_block)
1770                         goto out;
1771                 if (TC_H_MIN(tcm->tcm_parent)) {
1772                         cl = cops->find(q, tcm->tcm_parent);
1773                         if (cl == 0)
1774                                 goto out;
1775                 }
1776                 block = cops->tcf_block(q, cl, NULL);
1777                 if (!block)
1778                         goto out;
1779                 if (tcf_block_shared(block))
1780                         q = NULL;
1781         }
1782 
1783         index_start = cb->args[0];
1784         index = 0;
1785 
1786         list_for_each_entry(chain, &block->chain_list, list) {
1787                 if (tca[TCA_CHAIN] &&
1788                     nla_get_u32(tca[TCA_CHAIN]) != chain->index)
1789                         continue;
1790                 if (!tcf_chain_dump(chain, q, parent, skb, cb,
1791                                     index_start, &index)) {
1792                         err = -EMSGSIZE;
1793                         break;
1794                 }
1795         }
1796 
1797         if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK)
1798                 tcf_block_refcnt_put(block);
1799         cb->args[0] = index;
1800 
1801 out:
1802         /* If we did no progress, the error (EMSGSIZE) is real */
1803         if (skb->len == 0 && err)
1804                 return err;
1805         return skb->len;
1806 }
1807 
1808 static int tc_chain_fill_node(struct tcf_chain *chain, struct net *net,
1809                               struct sk_buff *skb, struct tcf_block *block,
1810                               u32 portid, u32 seq, u16 flags, int event)
1811 {
1812         unsigned char *b = skb_tail_pointer(skb);
1813         const struct tcf_proto_ops *ops;
1814         struct nlmsghdr *nlh;
1815         struct tcmsg *tcm;
1816         void *priv;
1817 
1818         ops = chain->tmplt_ops;
1819         priv = chain->tmplt_priv;
1820 
1821         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
1822         if (!nlh)
1823                 goto out_nlmsg_trim;
1824         tcm = nlmsg_data(nlh);
1825         tcm->tcm_family = AF_UNSPEC;
1826         tcm->tcm__pad1 = 0;
1827         tcm->tcm__pad2 = 0;
1828         tcm->tcm_handle = 0;
1829         if (block->q) {
1830                 tcm->tcm_ifindex = qdisc_dev(block->q)->ifindex;
1831                 tcm->tcm_parent = block->q->handle;
1832         } else {
1833                 tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
1834                 tcm->tcm_block_index = block->index;
1835         }
1836 
1837         if (nla_put_u32(skb, TCA_CHAIN, chain->index))
1838                 goto nla_put_failure;
1839 
1840         if (ops) {
1841                 if (nla_put_string(skb, TCA_KIND, ops->kind))
1842                         goto nla_put_failure;
1843                 if (ops->tmplt_dump(skb, net, priv) < 0)
1844                         goto nla_put_failure;
1845         }
1846 
1847         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1848         return skb->len;
1849 
1850 out_nlmsg_trim:
1851 nla_put_failure:
1852         nlmsg_trim(skb, b);
1853         return -EMSGSIZE;
1854 }
1855 
1856 static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
1857                            u32 seq, u16 flags, int event, bool unicast)
1858 {
1859         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1860         struct tcf_block *block = chain->block;
1861         struct net *net = block->net;
1862         struct sk_buff *skb;
1863 
1864         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1865         if (!skb)
1866                 return -ENOBUFS;
1867 
1868         if (tc_chain_fill_node(chain, net, skb, block, portid,
1869                                seq, flags, event) <= 0) {
1870                 kfree_skb(skb);
1871                 return -EINVAL;
1872         }
1873 
1874         if (unicast)
1875                 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
1876 
1877         return rtnetlink_send(skb, net, portid, RTNLGRP_TC, flags & NLM_F_ECHO);
1878 }
1879 
1880 static int tc_chain_tmplt_add(struct tcf_chain *chain, struct net *net,
1881                               struct nlattr **tca,
1882                               struct netlink_ext_ack *extack)
1883 {
1884         const struct tcf_proto_ops *ops;
1885         void *tmplt_priv;
1886 
1887         /* If kind is not set, user did not specify template. */
1888         if (!tca[TCA_KIND])
1889                 return 0;
1890 
1891         ops = tcf_proto_lookup_ops(nla_data(tca[TCA_KIND]), extack);
1892         if (IS_ERR(ops))
1893                 return PTR_ERR(ops);
1894         if (!ops->tmplt_create || !ops->tmplt_destroy || !ops->tmplt_dump) {
1895                 NL_SET_ERR_MSG(extack, "Chain templates are not supported with specified classifier");
1896                 return -EOPNOTSUPP;
1897         }
1898 
1899         tmplt_priv = ops->tmplt_create(net, chain, tca, extack);
1900         if (IS_ERR(tmplt_priv)) {
1901                 module_put(ops->owner);
1902                 return PTR_ERR(tmplt_priv);
1903         }
1904         chain->tmplt_ops = ops;
1905         chain->tmplt_priv = tmplt_priv;
1906         return 0;
1907 }
1908 
1909 static void tc_chain_tmplt_del(struct tcf_chain *chain)
1910 {
1911         const struct tcf_proto_ops *ops = chain->tmplt_ops;
1912 
1913         /* If template ops are set, no work to do for us. */
1914         if (!ops)
1915                 return;
1916 
1917         ops->tmplt_destroy(chain->tmplt_priv);
1918         module_put(ops->owner);
1919 }
1920 
1921 /* Add/delete/get a chain */
1922 
1923 static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n,
1924                         struct netlink_ext_ack *extack)
1925 {
1926         struct net *net = sock_net(skb->sk);
1927         struct nlattr *tca[TCA_MAX + 1];
1928         struct tcmsg *t;
1929         u32 parent;
1930         u32 chain_index;
1931         struct Qdisc *q = NULL;
1932         struct tcf_chain *chain = NULL;
1933         struct tcf_block *block;
1934         unsigned long cl;
1935         int err;
1936 
1937         if (n->nlmsg_type != RTM_GETCHAIN &&
1938             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1939                 return -EPERM;
1940 
1941 replay:
1942         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
1943         if (err < 0)
1944                 return err;
1945 
1946         t = nlmsg_data(n);
1947         parent = t->tcm_parent;
1948         cl = 0;
1949 
1950         block = tcf_block_find(net, &q, &parent, &cl,
1951                                t->tcm_ifindex, t->tcm_block_index, extack);
1952         if (IS_ERR(block))
1953                 return PTR_ERR(block);
1954 
1955         chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
1956         if (chain_index > TC_ACT_EXT_VAL_MASK) {
1957                 NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
1958                 err = -EINVAL;
1959                 goto errout_block;
1960         }
1961         chain = tcf_chain_lookup(block, chain_index);
1962         if (n->nlmsg_type == RTM_NEWCHAIN) {
1963                 if (chain) {
1964                         if (tcf_chain_held_by_acts_only(chain)) {
1965                                 /* The chain exists only because there is
1966                                  * some action referencing it.
1967                                  */
1968                                 tcf_chain_hold(chain);
1969                         } else {
1970                                 NL_SET_ERR_MSG(extack, "Filter chain already exists");
1971                                 err = -EEXIST;
1972                                 goto errout_block;
1973                         }
1974                 } else {
1975                         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
1976                                 NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain");
1977                                 err = -ENOENT;
1978                                 goto errout_block;
1979                         }
1980                         chain = tcf_chain_create(block, chain_index);
1981                         if (!chain) {
1982                                 NL_SET_ERR_MSG(extack, "Failed to create filter chain");
1983                                 err = -ENOMEM;
1984                                 goto errout_block;
1985                         }
1986                 }
1987         } else {
1988                 if (!chain || tcf_chain_held_by_acts_only(chain)) {
1989                         NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
1990                         err = -EINVAL;
1991                         goto errout_block;
1992                 }
1993                 tcf_chain_hold(chain);
1994         }
1995 
1996         switch (n->nlmsg_type) {
1997         case RTM_NEWCHAIN:
1998                 err = tc_chain_tmplt_add(chain, net, tca, extack);
1999                 if (err)
2000                         goto errout;
2001                 /* In case the chain was successfully added, take a reference
2002                  * to the chain. This ensures that an empty chain
2003                  * does not disappear at the end of this function.
2004                  */
2005                 tcf_chain_hold(chain);
2006                 chain->explicitly_created = true;
2007                 tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
2008                                 RTM_NEWCHAIN, false);
2009                 break;
2010         case RTM_DELCHAIN:
2011                 tfilter_notify_chain(net, skb, block, q, parent, n,
2012                                      chain, RTM_DELTFILTER);
2013                 /* Flush the chain first as the user requested chain removal. */
2014                 tcf_chain_flush(chain);
2015                 /* In case the chain was successfully deleted, put a reference
2016                  * to the chain previously taken during addition.
2017                  */
2018                 tcf_chain_put_explicitly_created(chain);
2019                 chain->explicitly_created = false;
2020                 break;
2021         case RTM_GETCHAIN:
2022                 err = tc_chain_notify(chain, skb, n->nlmsg_seq,
2023                                       n->nlmsg_seq, n->nlmsg_type, true);
2024                 if (err < 0)
2025                         NL_SET_ERR_MSG(extack, "Failed to send chain notify message");
2026                 break;
2027         default:
2028                 err = -EOPNOTSUPP;
2029                 NL_SET_ERR_MSG(extack, "Unsupported message type");
2030                 goto errout;
2031         }
2032 
2033 errout:
2034         tcf_chain_put(chain);
2035 errout_block:
2036         tcf_block_release(q, block);
2037         if (err == -EAGAIN)
2038                 /* Replay the request. */
2039                 goto replay;
2040         return err;
2041 }
2042 
2043 /* called with RTNL */
2044 static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb)
2045 {
2046         struct net *net = sock_net(skb->sk);
2047         struct nlattr *tca[TCA_MAX + 1];
2048         struct Qdisc *q = NULL;
2049         struct tcf_block *block;
2050         struct tcf_chain *chain;
2051         struct tcmsg *tcm = nlmsg_data(cb->nlh);
2052         long index_start;
2053         long index;
2054         u32 parent;
2055         int err;
2056 
2057         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
2058                 return skb->len;
2059 
2060         err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
2061                           cb->extack);
2062         if (err)
2063                 return err;
2064 
2065         if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
2066                 block = tcf_block_refcnt_get(net, tcm->tcm_block_index);
2067                 if (!block)
2068                         goto out;
2069                 /* If we work with block index, q is NULL and parent value
2070                  * will never be used in the following code. The check
2071                  * in tcf_fill_node prevents it. However, compiler does not
2072                  * see that far, so set parent to zero to silence the warning
2073                  * about parent being uninitialized.
2074                  */
2075                 parent = 0;
2076         } else {
2077                 const struct Qdisc_class_ops *cops;
2078                 struct net_device *dev;
2079                 unsigned long cl = 0;
2080 
2081                 dev = __dev_get_by_index(net, tcm->tcm_ifindex);
2082                 if (!dev)
2083                         return skb->len;
2084 
2085                 parent = tcm->tcm_parent;
2086                 if (!parent) {
2087                         q = dev->qdisc;
2088                         parent = q->handle;
2089                 } else {
2090                         q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
2091                 }
2092                 if (!q)
2093                         goto out;
2094                 cops = q->ops->cl_ops;
2095                 if (!cops)
2096                         goto out;
2097                 if (!cops->tcf_block)
2098                         goto out;
2099                 if (TC_H_MIN(tcm->tcm_parent)) {
2100                         cl = cops->find(q, tcm->tcm_parent);
2101                         if (cl == 0)
2102                                 goto out;
2103                 }
2104                 block = cops->tcf_block(q, cl, NULL);
2105                 if (!block)
2106                         goto out;
2107                 if (tcf_block_shared(block))
2108                         q = NULL;
2109         }
2110 
2111         index_start = cb->args[0];
2112         index = 0;
2113 
2114         list_for_each_entry(chain, &block->chain_list, list) {
2115                 if ((tca[TCA_CHAIN] &&
2116                      nla_get_u32(tca[TCA_CHAIN]) != chain->index))
2117                         continue;
2118                 if (index < index_start) {
2119                         index++;
2120                         continue;
2121                 }
2122                 if (tcf_chain_held_by_acts_only(chain))
2123                         continue;
2124                 err = tc_chain_fill_node(chain, net, skb, block,
2125                                          NETLINK_CB(cb->skb).portid,
2126                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
2127                                          RTM_NEWCHAIN);
2128                 if (err <= 0)
2129                         break;
2130                 index++;
2131         }
2132 
2133         if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK)
2134                 tcf_block_refcnt_put(block);
2135         cb->args[0] = index;
2136 
2137 out:
2138         /* If we did no progress, the error (EMSGSIZE) is real */
2139         if (skb->len == 0 && err)
2140                 return err;
2141         return skb->len;
2142 }
2143 
2144 void tcf_exts_destroy(struct tcf_exts *exts)
2145 {
2146 #ifdef CONFIG_NET_CLS_ACT
2147         tcf_action_destroy(exts->actions, TCA_ACT_UNBIND);
2148         kfree(exts->actions);
2149         exts->nr_actions = 0;
2150 #endif
2151 }
2152 EXPORT_SYMBOL(tcf_exts_destroy);
2153 
2154 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
2155                       struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr,
2156                       struct netlink_ext_ack *extack)
2157 {
2158 #ifdef CONFIG_NET_CLS_ACT
2159         {
2160                 struct tc_action *act;
2161                 size_t attr_size = 0;
2162 
2163                 if (exts->police && tb[exts->police]) {
2164                         act = tcf_action_init_1(net, tp, tb[exts->police],
2165                                                 rate_tlv, "police", ovr,
2166                                                 TCA_ACT_BIND, true, extack);
2167                         if (IS_ERR(act))
2168                                 return PTR_ERR(act);
2169 
2170                         act->type = exts->type = TCA_OLD_COMPAT;
2171                         exts->actions[0] = act;
2172                         exts->nr_actions = 1;
2173                 } else if (exts->action && tb[exts->action]) {
2174                         int err;
2175 
2176                         err = tcf_action_init(net, tp, tb[exts->action],
2177                                               rate_tlv, NULL, ovr, TCA_ACT_BIND,
2178                                               exts->actions, &attr_size, true,
2179                                               extack);
2180                         if (err < 0)
2181                                 return err;
2182                         exts->nr_actions = err;
2183                 }
2184                 exts->net = net;
2185         }
2186 #else
2187         if ((exts->action && tb[exts->action]) ||
2188             (exts->police && tb[exts->police])) {
2189                 NL_SET_ERR_MSG(extack, "Classifier actions are not supported per compile options (CONFIG_NET_CLS_ACT)");
2190                 return -EOPNOTSUPP;
2191         }
2192 #endif
2193 
2194         return 0;
2195 }
2196 EXPORT_SYMBOL(tcf_exts_validate);
2197 
2198 void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src)
2199 {
2200 #ifdef CONFIG_NET_CLS_ACT
2201         struct tcf_exts old = *dst;
2202 
2203         *dst = *src;
2204         tcf_exts_destroy(&old);
2205 #endif
2206 }
2207 EXPORT_SYMBOL(tcf_exts_change);
2208 
2209 #ifdef CONFIG_NET_CLS_ACT
2210 static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts)
2211 {
2212         if (exts->nr_actions == 0)
2213                 return NULL;
2214         else
2215                 return exts->actions[0];
2216 }
2217 #endif
2218 
2219 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
2220 {
2221 #ifdef CONFIG_NET_CLS_ACT
2222         struct nlattr *nest;
2223 
2224         if (exts->action && tcf_exts_has_actions(exts)) {
2225                 /*
2226                  * again for backward compatible mode - we want
2227                  * to work with both old and new modes of entering
2228                  * tc data even if iproute2  was newer - jhs
2229                  */
2230                 if (exts->type != TCA_OLD_COMPAT) {
2231                         nest = nla_nest_start(skb, exts->action);
2232                         if (nest == NULL)
2233                                 goto nla_put_failure;
2234 
2235                         if (tcf_action_dump(skb, exts->actions, 0, 0) < 0)
2236                                 goto nla_put_failure;
2237                         nla_nest_end(skb, nest);
2238                 } else if (exts->police) {
2239                         struct tc_action *act = tcf_exts_first_act(exts);
2240                         nest = nla_nest_start(skb, exts->police);
2241                         if (nest == NULL || !act)
2242                                 goto nla_put_failure;
2243                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
2244                                 goto nla_put_failure;
2245                         nla_nest_end(skb, nest);
2246                 }
2247         }
2248         return 0;
2249 
2250 nla_put_failure:
2251         nla_nest_cancel(skb, nest);
2252         return -1;
2253 #else
2254         return 0;
2255 #endif
2256 }
2257 EXPORT_SYMBOL(tcf_exts_dump);
2258 
2259 
2260 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
2261 {
2262 #ifdef CONFIG_NET_CLS_ACT
2263         struct tc_action *a = tcf_exts_first_act(exts);
2264         if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
2265                 return -1;
2266 #endif
2267         return 0;
2268 }
2269 EXPORT_SYMBOL(tcf_exts_dump_stats);
2270 
2271 static int tc_exts_setup_cb_egdev_call(struct tcf_exts *exts,
2272                                        enum tc_setup_type type,
2273                                        void *type_data, bool err_stop)
2274 {
2275         int ok_count = 0;
2276 #ifdef CONFIG_NET_CLS_ACT
2277         const struct tc_action *a;
2278         struct net_device *dev;
2279         int i, ret;
2280 
2281         if (!tcf_exts_has_actions(exts))
2282                 return 0;
2283 
2284         for (i = 0; i < exts->nr_actions; i++) {
2285                 a = exts->actions[i];
2286                 if (!a->ops->get_dev)
2287                         continue;
2288                 dev = a->ops->get_dev(a);
2289                 if (!dev)
2290                         continue;
2291                 ret = tc_setup_cb_egdev_call(dev, type, type_data, err_stop);
2292                 a->ops->put_dev(dev);
2293                 if (ret < 0)
2294                         return ret;
2295                 ok_count += ret;
2296         }
2297 #endif
2298         return ok_count;
2299 }
2300 
2301 int tc_setup_cb_call(struct tcf_block *block, struct tcf_exts *exts,
2302                      enum tc_setup_type type, void *type_data, bool err_stop)
2303 {
2304         int ok_count;
2305         int ret;
2306 
2307         ret = tcf_block_cb_call(block, type, type_data, err_stop);
2308         if (ret < 0)
2309                 return ret;
2310         ok_count = ret;
2311 
2312         if (!exts || ok_count)
2313                 return ok_count;
2314         ret = tc_exts_setup_cb_egdev_call(exts, type, type_data, err_stop);
2315         if (ret < 0)
2316                 return ret;
2317         ok_count += ret;
2318 
2319         return ok_count;
2320 }
2321 EXPORT_SYMBOL(tc_setup_cb_call);
2322 
2323 static __net_init int tcf_net_init(struct net *net)
2324 {
2325         struct tcf_net *tn = net_generic(net, tcf_net_id);
2326 
2327         spin_lock_init(&tn->idr_lock);
2328         idr_init(&tn->idr);
2329         return 0;
2330 }
2331 
2332 static void __net_exit tcf_net_exit(struct net *net)
2333 {
2334         struct tcf_net *tn = net_generic(net, tcf_net_id);
2335 
2336         idr_destroy(&tn->idr);
2337 }
2338 
2339 static struct pernet_operations tcf_net_ops = {
2340         .init = tcf_net_init,
2341         .exit = tcf_net_exit,
2342         .id   = &tcf_net_id,
2343         .size = sizeof(struct tcf_net),
2344 };
2345 
2346 static int __init tc_filter_init(void)
2347 {
2348         int err;
2349 
2350         tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
2351         if (!tc_filter_wq)
2352                 return -ENOMEM;
2353 
2354         err = register_pernet_subsys(&tcf_net_ops);
2355         if (err)
2356                 goto err_register_pernet_subsys;
2357 
2358         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_new_tfilter, NULL, 0);
2359         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_del_tfilter, NULL, 0);
2360         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_get_tfilter,
2361                       tc_dump_tfilter, 0);
2362         rtnl_register(PF_UNSPEC, RTM_NEWCHAIN, tc_ctl_chain, NULL, 0);
2363         rtnl_register(PF_UNSPEC, RTM_DELCHAIN, tc_ctl_chain, NULL, 0);
2364         rtnl_register(PF_UNSPEC, RTM_GETCHAIN, tc_ctl_chain,
2365                       tc_dump_chain, 0);
2366 
2367         return 0;
2368 
2369 err_register_pernet_subsys:
2370         destroy_workqueue(tc_filter_wq);
2371         return err;
2372 }
2373 
2374 subsys_initcall(tc_filter_init);
2375 

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