3725d8fa29db7c02185636336bba3cd59922d124
[pandora-kernel.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/netlink.h>
26 #include <linux/err.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
35 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
36
37 /* Protects list of registered TC modules. It is pure SMP lock. */
38 static DEFINE_RWLOCK(cls_mod_lock);
39
40 /* Find classifier type by string name */
41
42 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
43 {
44         struct tcf_proto_ops *t = NULL;
45
46         if (kind) {
47                 read_lock(&cls_mod_lock);
48                 for (t = tcf_proto_base; t; t = t->next) {
49                         if (nla_strcmp(kind, t->kind) == 0) {
50                                 if (!try_module_get(t->owner))
51                                         t = NULL;
52                                 break;
53                         }
54                 }
55                 read_unlock(&cls_mod_lock);
56         }
57         return t;
58 }
59
60 /* Register(unregister) new classifier type */
61
62 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
63 {
64         struct tcf_proto_ops *t, **tp;
65         int rc = -EEXIST;
66
67         write_lock(&cls_mod_lock);
68         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
69                 if (!strcmp(ops->kind, t->kind))
70                         goto out;
71
72         ops->next = NULL;
73         *tp = ops;
74         rc = 0;
75 out:
76         write_unlock(&cls_mod_lock);
77         return rc;
78 }
79 EXPORT_SYMBOL(register_tcf_proto_ops);
80
81 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
82 {
83         struct tcf_proto_ops *t, **tp;
84         int rc = -ENOENT;
85
86         write_lock(&cls_mod_lock);
87         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
88                 if (t == ops)
89                         break;
90
91         if (!t)
92                 goto out;
93         *tp = t->next;
94         rc = 0;
95 out:
96         write_unlock(&cls_mod_lock);
97         return rc;
98 }
99 EXPORT_SYMBOL(unregister_tcf_proto_ops);
100
101 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
102                           struct tcf_proto *tp, unsigned long fh, int event);
103
104
105 /* Select new prio value from the range, managed by kernel. */
106
107 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
108 {
109         u32 first = TC_H_MAKE(0xC0000000U, 0U);
110
111         if (tp)
112                 first = tp->prio-1;
113
114         return first;
115 }
116
117 /* Add/change/delete/get a filter node */
118
119 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
120 {
121         struct net *net = sock_net(skb->sk);
122         struct nlattr *tca[TCA_MAX + 1];
123         spinlock_t *root_lock;
124         struct tcmsg *t;
125         u32 protocol;
126         u32 prio;
127         u32 nprio;
128         u32 parent;
129         struct net_device *dev;
130         struct Qdisc  *q;
131         struct tcf_proto **back, **chain;
132         struct tcf_proto *tp;
133         struct tcf_proto_ops *tp_ops;
134         const struct Qdisc_class_ops *cops;
135         unsigned long cl;
136         unsigned long fh;
137         int err;
138         int tp_created = 0;
139
140         if (!net_eq(net, &init_net))
141                 return -EINVAL;
142
143 replay:
144         t = NLMSG_DATA(n);
145         protocol = TC_H_MIN(t->tcm_info);
146         prio = TC_H_MAJ(t->tcm_info);
147         nprio = prio;
148         parent = t->tcm_parent;
149         cl = 0;
150
151         if (prio == 0) {
152                 /* If no priority is given, user wants we allocated it. */
153                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
154                         return -ENOENT;
155                 prio = TC_H_MAKE(0x80000000U, 0U);
156         }
157
158         /* Find head of filter chain. */
159
160         /* Find link */
161         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
162         if (dev == NULL)
163                 return -ENODEV;
164
165         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
166         if (err < 0)
167                 return err;
168
169         /* Find qdisc */
170         if (!parent) {
171                 q = dev->qdisc;
172                 parent = q->handle;
173         } else {
174                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
175                 if (q == NULL)
176                         return -EINVAL;
177         }
178
179         /* Is it classful? */
180         if ((cops = q->ops->cl_ops) == NULL)
181                 return -EINVAL;
182
183         if (cops->tcf_chain == NULL)
184                 return -EOPNOTSUPP;
185
186         /* Do we search for filter, attached to class? */
187         if (TC_H_MIN(parent)) {
188                 cl = cops->get(q, parent);
189                 if (cl == 0)
190                         return -ENOENT;
191         }
192
193         /* And the last stroke */
194         chain = cops->tcf_chain(q, cl);
195         err = -EINVAL;
196         if (chain == NULL)
197                 goto errout;
198
199         /* Check the chain for existence of proto-tcf with this priority */
200         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
201                 if (tp->prio >= prio) {
202                         if (tp->prio == prio) {
203                                 if (!nprio || (tp->protocol != protocol && protocol))
204                                         goto errout;
205                         } else
206                                 tp = NULL;
207                         break;
208                 }
209         }
210
211         root_lock = qdisc_root_sleeping_lock(q);
212
213         if (tp == NULL) {
214                 /* Proto-tcf does not exist, create new one */
215
216                 if (tca[TCA_KIND] == NULL || !protocol)
217                         goto errout;
218
219                 err = -ENOENT;
220                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
221                         goto errout;
222
223
224                 /* Create new proto tcf */
225
226                 err = -ENOBUFS;
227                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
228                 if (tp == NULL)
229                         goto errout;
230                 err = -ENOENT;
231                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
232                 if (tp_ops == NULL) {
233 #ifdef CONFIG_MODULES
234                         struct nlattr *kind = tca[TCA_KIND];
235                         char name[IFNAMSIZ];
236
237                         if (kind != NULL &&
238                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
239                                 rtnl_unlock();
240                                 request_module("cls_%s", name);
241                                 rtnl_lock();
242                                 tp_ops = tcf_proto_lookup_ops(kind);
243                                 /* We dropped the RTNL semaphore in order to
244                                  * perform the module load.  So, even if we
245                                  * succeeded in loading the module we have to
246                                  * replay the request.  We indicate this using
247                                  * -EAGAIN.
248                                  */
249                                 if (tp_ops != NULL) {
250                                         module_put(tp_ops->owner);
251                                         err = -EAGAIN;
252                                 }
253                         }
254 #endif
255                         kfree(tp);
256                         goto errout;
257                 }
258                 tp->ops = tp_ops;
259                 tp->protocol = protocol;
260                 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
261                 tp->q = q;
262                 tp->classify = tp_ops->classify;
263                 tp->classid = parent;
264
265                 err = tp_ops->init(tp);
266                 if (err != 0) {
267                         module_put(tp_ops->owner);
268                         kfree(tp);
269                         goto errout;
270                 }
271
272                 tp_created = 1;
273
274         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
275                 goto errout;
276
277         fh = tp->ops->get(tp, t->tcm_handle);
278
279         if (fh == 0) {
280                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
281                         spin_lock_bh(root_lock);
282                         *back = tp->next;
283                         spin_unlock_bh(root_lock);
284
285                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
286                         tcf_destroy(tp);
287                         err = 0;
288                         goto errout;
289                 }
290
291                 err = -ENOENT;
292                 if (n->nlmsg_type != RTM_NEWTFILTER ||
293                     !(n->nlmsg_flags & NLM_F_CREATE))
294                         goto errout;
295         } else {
296                 switch (n->nlmsg_type) {
297                 case RTM_NEWTFILTER:
298                         err = -EEXIST;
299                         if (n->nlmsg_flags & NLM_F_EXCL) {
300                                 if (tp_created)
301                                         tcf_destroy(tp);
302                                 goto errout;
303                         }
304                         break;
305                 case RTM_DELTFILTER:
306                         err = tp->ops->delete(tp, fh);
307                         if (err == 0)
308                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
309                         goto errout;
310                 case RTM_GETTFILTER:
311                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
312                         goto errout;
313                 default:
314                         err = -EINVAL;
315                         goto errout;
316                 }
317         }
318
319         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
320         if (err == 0) {
321                 if (tp_created) {
322                         spin_lock_bh(root_lock);
323                         tp->next = *back;
324                         *back = tp;
325                         spin_unlock_bh(root_lock);
326                 }
327                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
328         } else {
329                 if (tp_created)
330                         tcf_destroy(tp);
331         }
332
333 errout:
334         if (cl)
335                 cops->put(q, cl);
336         if (err == -EAGAIN)
337                 /* Replay the request. */
338                 goto replay;
339         return err;
340 }
341
342 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
343                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
344 {
345         struct tcmsg *tcm;
346         struct nlmsghdr  *nlh;
347         unsigned char *b = skb_tail_pointer(skb);
348
349         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
350         tcm = NLMSG_DATA(nlh);
351         tcm->tcm_family = AF_UNSPEC;
352         tcm->tcm__pad1 = 0;
353         tcm->tcm__pad2 = 0;
354         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
355         tcm->tcm_parent = tp->classid;
356         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
357         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
358         tcm->tcm_handle = fh;
359         if (RTM_DELTFILTER != event) {
360                 tcm->tcm_handle = 0;
361                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
362                         goto nla_put_failure;
363         }
364         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
365         return skb->len;
366
367 nlmsg_failure:
368 nla_put_failure:
369         nlmsg_trim(skb, b);
370         return -1;
371 }
372
373 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
374                           struct tcf_proto *tp, unsigned long fh, int event)
375 {
376         struct sk_buff *skb;
377         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
378
379         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
380         if (!skb)
381                 return -ENOBUFS;
382
383         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
384                 kfree_skb(skb);
385                 return -EINVAL;
386         }
387
388         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
389                               n->nlmsg_flags & NLM_F_ECHO);
390 }
391
392 struct tcf_dump_args {
393         struct tcf_walker w;
394         struct sk_buff *skb;
395         struct netlink_callback *cb;
396 };
397
398 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
399                          struct tcf_walker *arg)
400 {
401         struct tcf_dump_args *a = (void *)arg;
402
403         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
404                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
405 }
406
407 /* called with RTNL */
408 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
409 {
410         struct net *net = sock_net(skb->sk);
411         int t;
412         int s_t;
413         struct net_device *dev;
414         struct Qdisc *q;
415         struct tcf_proto *tp, **chain;
416         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
417         unsigned long cl = 0;
418         const struct Qdisc_class_ops *cops;
419         struct tcf_dump_args arg;
420
421         if (!net_eq(net, &init_net))
422                 return 0;
423
424         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
425                 return skb->len;
426         if ((dev = __dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
427                 return skb->len;
428
429         if (!tcm->tcm_parent)
430                 q = dev->qdisc;
431         else
432                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
433         if (!q)
434                 goto out;
435         if ((cops = q->ops->cl_ops) == NULL)
436                 goto errout;
437         if (cops->tcf_chain == NULL)
438                 goto errout;
439         if (TC_H_MIN(tcm->tcm_parent)) {
440                 cl = cops->get(q, tcm->tcm_parent);
441                 if (cl == 0)
442                         goto errout;
443         }
444         chain = cops->tcf_chain(q, cl);
445         if (chain == NULL)
446                 goto errout;
447
448         s_t = cb->args[0];
449
450         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
451                 if (t < s_t) continue;
452                 if (TC_H_MAJ(tcm->tcm_info) &&
453                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
454                         continue;
455                 if (TC_H_MIN(tcm->tcm_info) &&
456                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
457                         continue;
458                 if (t > s_t)
459                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
460                 if (cb->args[1] == 0) {
461                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
462                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
463                                           RTM_NEWTFILTER) <= 0)
464                                 break;
465
466                         cb->args[1] = 1;
467                 }
468                 if (tp->ops->walk == NULL)
469                         continue;
470                 arg.w.fn = tcf_node_dump;
471                 arg.skb = skb;
472                 arg.cb = cb;
473                 arg.w.stop = 0;
474                 arg.w.skip = cb->args[1]-1;
475                 arg.w.count = 0;
476                 tp->ops->walk(tp, &arg.w);
477                 cb->args[1] = arg.w.count+1;
478                 if (arg.w.stop)
479                         break;
480         }
481
482         cb->args[0] = t;
483
484 errout:
485         if (cl)
486                 cops->put(q, cl);
487 out:
488         return skb->len;
489 }
490
491 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
492 {
493 #ifdef CONFIG_NET_CLS_ACT
494         if (exts->action) {
495                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
496                 exts->action = NULL;
497         }
498 #endif
499 }
500 EXPORT_SYMBOL(tcf_exts_destroy);
501
502 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
503                   struct nlattr *rate_tlv, struct tcf_exts *exts,
504                   const struct tcf_ext_map *map)
505 {
506         memset(exts, 0, sizeof(*exts));
507
508 #ifdef CONFIG_NET_CLS_ACT
509         {
510                 struct tc_action *act;
511
512                 if (map->police && tb[map->police]) {
513                         act = tcf_action_init_1(tb[map->police], rate_tlv,
514                                                 "police", TCA_ACT_NOREPLACE,
515                                                 TCA_ACT_BIND);
516                         if (IS_ERR(act))
517                                 return PTR_ERR(act);
518
519                         act->type = TCA_OLD_COMPAT;
520                         exts->action = act;
521                 } else if (map->action && tb[map->action]) {
522                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
523                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
524                         if (IS_ERR(act))
525                                 return PTR_ERR(act);
526
527                         exts->action = act;
528                 }
529         }
530 #else
531         if ((map->action && tb[map->action]) ||
532             (map->police && tb[map->police]))
533                 return -EOPNOTSUPP;
534 #endif
535
536         return 0;
537 }
538 EXPORT_SYMBOL(tcf_exts_validate);
539
540 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
541                      struct tcf_exts *src)
542 {
543 #ifdef CONFIG_NET_CLS_ACT
544         if (src->action) {
545                 struct tc_action *act;
546                 tcf_tree_lock(tp);
547                 act = dst->action;
548                 dst->action = src->action;
549                 tcf_tree_unlock(tp);
550                 if (act)
551                         tcf_action_destroy(act, TCA_ACT_UNBIND);
552         }
553 #endif
554 }
555 EXPORT_SYMBOL(tcf_exts_change);
556
557 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
558                   const struct tcf_ext_map *map)
559 {
560 #ifdef CONFIG_NET_CLS_ACT
561         if (map->action && exts->action) {
562                 /*
563                  * again for backward compatible mode - we want
564                  * to work with both old and new modes of entering
565                  * tc data even if iproute2  was newer - jhs
566                  */
567                 struct nlattr *nest;
568
569                 if (exts->action->type != TCA_OLD_COMPAT) {
570                         nest = nla_nest_start(skb, map->action);
571                         if (nest == NULL)
572                                 goto nla_put_failure;
573                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
574                                 goto nla_put_failure;
575                         nla_nest_end(skb, nest);
576                 } else if (map->police) {
577                         nest = nla_nest_start(skb, map->police);
578                         if (nest == NULL)
579                                 goto nla_put_failure;
580                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
581                                 goto nla_put_failure;
582                         nla_nest_end(skb, nest);
583                 }
584         }
585 #endif
586         return 0;
587 nla_put_failure: __attribute__ ((unused))
588         return -1;
589 }
590 EXPORT_SYMBOL(tcf_exts_dump);
591
592
593 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
594                         const struct tcf_ext_map *map)
595 {
596 #ifdef CONFIG_NET_CLS_ACT
597         if (exts->action)
598                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
599                         goto nla_put_failure;
600 #endif
601         return 0;
602 nla_put_failure: __attribute__ ((unused))
603         return -1;
604 }
605 EXPORT_SYMBOL(tcf_exts_dump_stats);
606
607 static int __init tc_filter_init(void)
608 {
609         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
610         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
611         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
612                                                  tc_dump_tfilter);
613
614         return 0;
615 }
616
617 subsys_initcall(tc_filter_init);