regulator: Kconfig: Fix typo
[cascardo/linux.git] / 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/skbuff.h>
23 #include <linux/init.h>
24 #include <linux/kmod.h>
25 #include <linux/err.h>
26 #include <linux/slab.h>
27 #include <net/net_namespace.h>
28 #include <net/sock.h>
29 #include <net/netlink.h>
30 #include <net/pkt_sched.h>
31 #include <net/pkt_cls.h>
32
33 /* The list of all installed classifier types */
34 static LIST_HEAD(tcf_proto_base);
35
36 /* Protects list of registered TC modules. It is pure SMP lock. */
37 static DEFINE_RWLOCK(cls_mod_lock);
38
39 /* Find classifier type by string name */
40
41 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
42 {
43         const struct tcf_proto_ops *t, *res = NULL;
44
45         if (kind) {
46                 read_lock(&cls_mod_lock);
47                 list_for_each_entry(t, &tcf_proto_base, head) {
48                         if (nla_strcmp(kind, t->kind) == 0) {
49                                 if (try_module_get(t->owner))
50                                         res = t;
51                                 break;
52                         }
53                 }
54                 read_unlock(&cls_mod_lock);
55         }
56         return res;
57 }
58
59 /* Register(unregister) new classifier type */
60
61 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
62 {
63         struct tcf_proto_ops *t;
64         int rc = -EEXIST;
65
66         write_lock(&cls_mod_lock);
67         list_for_each_entry(t, &tcf_proto_base, head)
68                 if (!strcmp(ops->kind, t->kind))
69                         goto out;
70
71         list_add_tail(&ops->head, &tcf_proto_base);
72         rc = 0;
73 out:
74         write_unlock(&cls_mod_lock);
75         return rc;
76 }
77 EXPORT_SYMBOL(register_tcf_proto_ops);
78
79 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
80 {
81         struct tcf_proto_ops *t;
82         int rc = -ENOENT;
83
84         /* Wait for outstanding call_rcu()s, if any, from a
85          * tcf_proto_ops's destroy() handler.
86          */
87         rcu_barrier();
88
89         write_lock(&cls_mod_lock);
90         list_for_each_entry(t, &tcf_proto_base, head) {
91                 if (t == ops) {
92                         list_del(&t->head);
93                         rc = 0;
94                         break;
95                 }
96         }
97         write_unlock(&cls_mod_lock);
98         return rc;
99 }
100 EXPORT_SYMBOL(unregister_tcf_proto_ops);
101
102 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
103                           struct nlmsghdr *n, struct tcf_proto *tp,
104                           unsigned long fh, int event);
105
106 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
107                                  struct nlmsghdr *n,
108                                  struct tcf_proto __rcu **chain, int event)
109 {
110         struct tcf_proto __rcu **it_chain;
111         struct tcf_proto *tp;
112
113         for (it_chain = chain; (tp = rtnl_dereference(*it_chain)) != NULL;
114              it_chain = &tp->next)
115                 tfilter_notify(net, oskb, n, tp, 0, event);
116 }
117
118 /* Select new prio value from the range, managed by kernel. */
119
120 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
121 {
122         u32 first = TC_H_MAKE(0xC0000000U, 0U);
123
124         if (tp)
125                 first = tp->prio - 1;
126
127         return first;
128 }
129
130 /* Add/change/delete/get a filter node */
131
132 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n)
133 {
134         struct net *net = sock_net(skb->sk);
135         struct nlattr *tca[TCA_MAX + 1];
136         struct tcmsg *t;
137         u32 protocol;
138         u32 prio;
139         u32 nprio;
140         u32 parent;
141         struct net_device *dev;
142         struct Qdisc  *q;
143         struct tcf_proto __rcu **back;
144         struct tcf_proto __rcu **chain;
145         struct tcf_proto *tp;
146         const struct tcf_proto_ops *tp_ops;
147         const struct Qdisc_class_ops *cops;
148         unsigned long cl;
149         unsigned long fh;
150         int err;
151         int tp_created = 0;
152
153         if ((n->nlmsg_type != RTM_GETTFILTER) &&
154             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
155                 return -EPERM;
156
157 replay:
158         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
159         if (err < 0)
160                 return err;
161
162         t = nlmsg_data(n);
163         protocol = TC_H_MIN(t->tcm_info);
164         prio = TC_H_MAJ(t->tcm_info);
165         nprio = prio;
166         parent = t->tcm_parent;
167         cl = 0;
168
169         if (prio == 0) {
170                 switch (n->nlmsg_type) {
171                 case RTM_DELTFILTER:
172                         if (protocol || t->tcm_handle || tca[TCA_KIND])
173                                 return -ENOENT;
174                         break;
175                 case RTM_NEWTFILTER:
176                         /* If no priority is provided by the user,
177                          * we allocate one.
178                          */
179                         if (n->nlmsg_flags & NLM_F_CREATE) {
180                                 prio = TC_H_MAKE(0x80000000U, 0U);
181                                 break;
182                         }
183                         /* fall-through */
184                 default:
185                         return -ENOENT;
186                 }
187         }
188
189         /* Find head of filter chain. */
190
191         /* Find link */
192         dev = __dev_get_by_index(net, t->tcm_ifindex);
193         if (dev == NULL)
194                 return -ENODEV;
195
196         /* Find qdisc */
197         if (!parent) {
198                 q = dev->qdisc;
199                 parent = q->handle;
200         } else {
201                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
202                 if (q == NULL)
203                         return -EINVAL;
204         }
205
206         /* Is it classful? */
207         cops = q->ops->cl_ops;
208         if (!cops)
209                 return -EINVAL;
210
211         if (cops->tcf_chain == NULL)
212                 return -EOPNOTSUPP;
213
214         /* Do we search for filter, attached to class? */
215         if (TC_H_MIN(parent)) {
216                 cl = cops->get(q, parent);
217                 if (cl == 0)
218                         return -ENOENT;
219         }
220
221         /* And the last stroke */
222         chain = cops->tcf_chain(q, cl);
223         err = -EINVAL;
224         if (chain == NULL)
225                 goto errout;
226         if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
227                 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
228                 tcf_destroy_chain(chain);
229                 err = 0;
230                 goto errout;
231         }
232
233         /* Check the chain for existence of proto-tcf with this priority */
234         for (back = chain;
235              (tp = rtnl_dereference(*back)) != NULL;
236              back = &tp->next) {
237                 if (tp->prio >= prio) {
238                         if (tp->prio == prio) {
239                                 if (!nprio ||
240                                     (tp->protocol != protocol && protocol))
241                                         goto errout;
242                         } else
243                                 tp = NULL;
244                         break;
245                 }
246         }
247
248         if (tp == NULL) {
249                 /* Proto-tcf does not exist, create new one */
250
251                 if (tca[TCA_KIND] == NULL || !protocol)
252                         goto errout;
253
254                 err = -ENOENT;
255                 if (n->nlmsg_type != RTM_NEWTFILTER ||
256                     !(n->nlmsg_flags & NLM_F_CREATE))
257                         goto errout;
258
259
260                 /* Create new proto tcf */
261
262                 err = -ENOBUFS;
263                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
264                 if (tp == NULL)
265                         goto errout;
266                 err = -ENOENT;
267                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
268                 if (tp_ops == NULL) {
269 #ifdef CONFIG_MODULES
270                         struct nlattr *kind = tca[TCA_KIND];
271                         char name[IFNAMSIZ];
272
273                         if (kind != NULL &&
274                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
275                                 rtnl_unlock();
276                                 request_module("cls_%s", name);
277                                 rtnl_lock();
278                                 tp_ops = tcf_proto_lookup_ops(kind);
279                                 /* We dropped the RTNL semaphore in order to
280                                  * perform the module load.  So, even if we
281                                  * succeeded in loading the module we have to
282                                  * replay the request.  We indicate this using
283                                  * -EAGAIN.
284                                  */
285                                 if (tp_ops != NULL) {
286                                         module_put(tp_ops->owner);
287                                         err = -EAGAIN;
288                                 }
289                         }
290 #endif
291                         kfree(tp);
292                         goto errout;
293                 }
294                 tp->ops = tp_ops;
295                 tp->protocol = protocol;
296                 tp->prio = nprio ? :
297                                TC_H_MAJ(tcf_auto_prio(rtnl_dereference(*back)));
298                 tp->q = q;
299                 tp->classify = tp_ops->classify;
300                 tp->classid = parent;
301
302                 err = tp_ops->init(tp);
303                 if (err != 0) {
304                         module_put(tp_ops->owner);
305                         kfree(tp);
306                         goto errout;
307                 }
308
309                 tp_created = 1;
310
311         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
312                 goto errout;
313
314         fh = tp->ops->get(tp, t->tcm_handle);
315
316         if (fh == 0) {
317                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
318                         struct tcf_proto *next = rtnl_dereference(tp->next);
319
320                         RCU_INIT_POINTER(*back, next);
321
322                         tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
323                         tcf_destroy(tp, true);
324                         err = 0;
325                         goto errout;
326                 }
327
328                 err = -ENOENT;
329                 if (n->nlmsg_type != RTM_NEWTFILTER ||
330                     !(n->nlmsg_flags & NLM_F_CREATE))
331                         goto errout;
332         } else {
333                 switch (n->nlmsg_type) {
334                 case RTM_NEWTFILTER:
335                         err = -EEXIST;
336                         if (n->nlmsg_flags & NLM_F_EXCL) {
337                                 if (tp_created)
338                                         tcf_destroy(tp, true);
339                                 goto errout;
340                         }
341                         break;
342                 case RTM_DELTFILTER:
343                         err = tp->ops->delete(tp, fh);
344                         if (err == 0) {
345                                 struct tcf_proto *next = rtnl_dereference(tp->next);
346
347                                 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
348                                 if (tcf_destroy(tp, false))
349                                         RCU_INIT_POINTER(*back, next);
350                         }
351                         goto errout;
352                 case RTM_GETTFILTER:
353                         err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
354                         goto errout;
355                 default:
356                         err = -EINVAL;
357                         goto errout;
358                 }
359         }
360
361         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
362                               n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
363         if (err == 0) {
364                 if (tp_created) {
365                         RCU_INIT_POINTER(tp->next, rtnl_dereference(*back));
366                         rcu_assign_pointer(*back, tp);
367                 }
368                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
369         } else {
370                 if (tp_created)
371                         tcf_destroy(tp, true);
372         }
373
374 errout:
375         if (cl)
376                 cops->put(q, cl);
377         if (err == -EAGAIN)
378                 /* Replay the request. */
379                 goto replay;
380         return err;
381 }
382
383 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
384                          struct tcf_proto *tp, unsigned long fh, u32 portid,
385                          u32 seq, u16 flags, int event)
386 {
387         struct tcmsg *tcm;
388         struct nlmsghdr  *nlh;
389         unsigned char *b = skb_tail_pointer(skb);
390
391         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
392         if (!nlh)
393                 goto out_nlmsg_trim;
394         tcm = nlmsg_data(nlh);
395         tcm->tcm_family = AF_UNSPEC;
396         tcm->tcm__pad1 = 0;
397         tcm->tcm__pad2 = 0;
398         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
399         tcm->tcm_parent = tp->classid;
400         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
401         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
402                 goto nla_put_failure;
403         tcm->tcm_handle = fh;
404         if (RTM_DELTFILTER != event) {
405                 tcm->tcm_handle = 0;
406                 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
407                         goto nla_put_failure;
408         }
409         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
410         return skb->len;
411
412 out_nlmsg_trim:
413 nla_put_failure:
414         nlmsg_trim(skb, b);
415         return -1;
416 }
417
418 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
419                           struct nlmsghdr *n, struct tcf_proto *tp,
420                           unsigned long fh, int event)
421 {
422         struct sk_buff *skb;
423         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
424
425         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
426         if (!skb)
427                 return -ENOBUFS;
428
429         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) {
430                 kfree_skb(skb);
431                 return -EINVAL;
432         }
433
434         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
435                               n->nlmsg_flags & NLM_F_ECHO);
436 }
437
438 struct tcf_dump_args {
439         struct tcf_walker w;
440         struct sk_buff *skb;
441         struct netlink_callback *cb;
442 };
443
444 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
445                          struct tcf_walker *arg)
446 {
447         struct tcf_dump_args *a = (void *)arg;
448         struct net *net = sock_net(a->skb->sk);
449
450         return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
451                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
452 }
453
454 /* called with RTNL */
455 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
456 {
457         struct net *net = sock_net(skb->sk);
458         int t;
459         int s_t;
460         struct net_device *dev;
461         struct Qdisc *q;
462         struct tcf_proto *tp, __rcu **chain;
463         struct tcmsg *tcm = nlmsg_data(cb->nlh);
464         unsigned long cl = 0;
465         const struct Qdisc_class_ops *cops;
466         struct tcf_dump_args arg;
467
468         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
469                 return skb->len;
470         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
471         if (!dev)
472                 return skb->len;
473
474         if (!tcm->tcm_parent)
475                 q = dev->qdisc;
476         else
477                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
478         if (!q)
479                 goto out;
480         cops = q->ops->cl_ops;
481         if (!cops)
482                 goto errout;
483         if (cops->tcf_chain == NULL)
484                 goto errout;
485         if (TC_H_MIN(tcm->tcm_parent)) {
486                 cl = cops->get(q, tcm->tcm_parent);
487                 if (cl == 0)
488                         goto errout;
489         }
490         chain = cops->tcf_chain(q, cl);
491         if (chain == NULL)
492                 goto errout;
493
494         s_t = cb->args[0];
495
496         for (tp = rtnl_dereference(*chain), t = 0;
497              tp; tp = rtnl_dereference(tp->next), t++) {
498                 if (t < s_t)
499                         continue;
500                 if (TC_H_MAJ(tcm->tcm_info) &&
501                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
502                         continue;
503                 if (TC_H_MIN(tcm->tcm_info) &&
504                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
505                         continue;
506                 if (t > s_t)
507                         memset(&cb->args[1], 0,
508                                sizeof(cb->args)-sizeof(cb->args[0]));
509                 if (cb->args[1] == 0) {
510                         if (tcf_fill_node(net, skb, tp, 0,
511                                           NETLINK_CB(cb->skb).portid,
512                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
513                                           RTM_NEWTFILTER) <= 0)
514                                 break;
515
516                         cb->args[1] = 1;
517                 }
518                 if (tp->ops->walk == NULL)
519                         continue;
520                 arg.w.fn = tcf_node_dump;
521                 arg.skb = skb;
522                 arg.cb = cb;
523                 arg.w.stop = 0;
524                 arg.w.skip = cb->args[1] - 1;
525                 arg.w.count = 0;
526                 tp->ops->walk(tp, &arg.w);
527                 cb->args[1] = arg.w.count + 1;
528                 if (arg.w.stop)
529                         break;
530         }
531
532         cb->args[0] = t;
533
534 errout:
535         if (cl)
536                 cops->put(q, cl);
537 out:
538         return skb->len;
539 }
540
541 void tcf_exts_destroy(struct tcf_exts *exts)
542 {
543 #ifdef CONFIG_NET_CLS_ACT
544         tcf_action_destroy(&exts->actions, TCA_ACT_UNBIND);
545         INIT_LIST_HEAD(&exts->actions);
546 #endif
547 }
548 EXPORT_SYMBOL(tcf_exts_destroy);
549
550 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
551                   struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
552 {
553 #ifdef CONFIG_NET_CLS_ACT
554         {
555                 struct tc_action *act;
556
557                 INIT_LIST_HEAD(&exts->actions);
558                 if (exts->police && tb[exts->police]) {
559                         act = tcf_action_init_1(net, tb[exts->police], rate_tlv,
560                                                 "police", ovr,
561                                                 TCA_ACT_BIND);
562                         if (IS_ERR(act))
563                                 return PTR_ERR(act);
564
565                         act->type = exts->type = TCA_OLD_COMPAT;
566                         list_add(&act->list, &exts->actions);
567                 } else if (exts->action && tb[exts->action]) {
568                         int err;
569                         err = tcf_action_init(net, tb[exts->action], rate_tlv,
570                                               NULL, ovr,
571                                               TCA_ACT_BIND, &exts->actions);
572                         if (err)
573                                 return err;
574                 }
575         }
576 #else
577         if ((exts->action && tb[exts->action]) ||
578             (exts->police && tb[exts->police]))
579                 return -EOPNOTSUPP;
580 #endif
581
582         return 0;
583 }
584 EXPORT_SYMBOL(tcf_exts_validate);
585
586 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
587                      struct tcf_exts *src)
588 {
589 #ifdef CONFIG_NET_CLS_ACT
590         LIST_HEAD(tmp);
591         tcf_tree_lock(tp);
592         list_splice_init(&dst->actions, &tmp);
593         list_splice(&src->actions, &dst->actions);
594         dst->type = src->type;
595         tcf_tree_unlock(tp);
596         tcf_action_destroy(&tmp, TCA_ACT_UNBIND);
597 #endif
598 }
599 EXPORT_SYMBOL(tcf_exts_change);
600
601 #define tcf_exts_first_act(ext)                                 \
602         list_first_entry_or_null(&(exts)->actions,              \
603                                  struct tc_action, list)
604
605 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
606 {
607 #ifdef CONFIG_NET_CLS_ACT
608         struct nlattr *nest;
609
610         if (exts->action && !list_empty(&exts->actions)) {
611                 /*
612                  * again for backward compatible mode - we want
613                  * to work with both old and new modes of entering
614                  * tc data even if iproute2  was newer - jhs
615                  */
616                 if (exts->type != TCA_OLD_COMPAT) {
617                         nest = nla_nest_start(skb, exts->action);
618                         if (nest == NULL)
619                                 goto nla_put_failure;
620                         if (tcf_action_dump(skb, &exts->actions, 0, 0) < 0)
621                                 goto nla_put_failure;
622                         nla_nest_end(skb, nest);
623                 } else if (exts->police) {
624                         struct tc_action *act = tcf_exts_first_act(exts);
625                         nest = nla_nest_start(skb, exts->police);
626                         if (nest == NULL || !act)
627                                 goto nla_put_failure;
628                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
629                                 goto nla_put_failure;
630                         nla_nest_end(skb, nest);
631                 }
632         }
633         return 0;
634
635 nla_put_failure:
636         nla_nest_cancel(skb, nest);
637         return -1;
638 #else
639         return 0;
640 #endif
641 }
642 EXPORT_SYMBOL(tcf_exts_dump);
643
644
645 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
646 {
647 #ifdef CONFIG_NET_CLS_ACT
648         struct tc_action *a = tcf_exts_first_act(exts);
649         if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
650                 return -1;
651 #endif
652         return 0;
653 }
654 EXPORT_SYMBOL(tcf_exts_dump_stats);
655
656 static int __init tc_filter_init(void)
657 {
658         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL);
659         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL);
660         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
661                       tc_dump_tfilter, NULL);
662
663         return 0;
664 }
665
666 subsys_initcall(tc_filter_init);