9eeb3c6c82f4e4aa557689aa23734f0467edaa0e
[linux-2.6.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 <net/net_namespace.h>
27 #include <net/sock.h>
28 #include <net/netlink.h>
29 #include <net/pkt_sched.h>
30 #include <net/pkt_cls.h>
31
32 /* The list of all installed classifier types */
33
34 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
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 struct tcf_proto_ops *tcf_proto_lookup_ops(struct rtattr *kind)
42 {
43         struct tcf_proto_ops *t = NULL;
44
45         if (kind) {
46                 read_lock(&cls_mod_lock);
47                 for (t = tcf_proto_base; t; t = t->next) {
48                         if (rtattr_strcmp(kind, t->kind) == 0) {
49                                 if (!try_module_get(t->owner))
50                                         t = NULL;
51                                 break;
52                         }
53                 }
54                 read_unlock(&cls_mod_lock);
55         }
56         return t;
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, **tp;
64         int rc = -EEXIST;
65
66         write_lock(&cls_mod_lock);
67         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
68                 if (!strcmp(ops->kind, t->kind))
69                         goto out;
70
71         ops->next = NULL;
72         *tp = ops;
73         rc = 0;
74 out:
75         write_unlock(&cls_mod_lock);
76         return rc;
77 }
78 EXPORT_SYMBOL(register_tcf_proto_ops);
79
80 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
81 {
82         struct tcf_proto_ops *t, **tp;
83         int rc = -ENOENT;
84
85         write_lock(&cls_mod_lock);
86         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
87                 if (t == ops)
88                         break;
89
90         if (!t)
91                 goto out;
92         *tp = t->next;
93         rc = 0;
94 out:
95         write_unlock(&cls_mod_lock);
96         return rc;
97 }
98 EXPORT_SYMBOL(unregister_tcf_proto_ops);
99
100 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
101                           struct tcf_proto *tp, unsigned long fh, int event);
102
103
104 /* Select new prio value from the range, managed by kernel. */
105
106 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
107 {
108         u32 first = TC_H_MAKE(0xC0000000U, 0U);
109
110         if (tp)
111                 first = tp->prio-1;
112
113         return first;
114 }
115
116 /* Add/change/delete/get a filter node */
117
118 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
119 {
120         struct net *net = skb->sk->sk_net;
121         struct rtattr **tca;
122         struct tcmsg *t;
123         u32 protocol;
124         u32 prio;
125         u32 nprio;
126         u32 parent;
127         struct net_device *dev;
128         struct Qdisc  *q;
129         struct tcf_proto **back, **chain;
130         struct tcf_proto *tp;
131         struct tcf_proto_ops *tp_ops;
132         const struct Qdisc_class_ops *cops;
133         unsigned long cl;
134         unsigned long fh;
135         int err;
136
137         if (net != &init_net)
138                 return -EINVAL;
139
140 replay:
141         tca = arg;
142         t = NLMSG_DATA(n);
143         protocol = TC_H_MIN(t->tcm_info);
144         prio = TC_H_MAJ(t->tcm_info);
145         nprio = prio;
146         parent = t->tcm_parent;
147         cl = 0;
148
149         if (prio == 0) {
150                 /* If no priority is given, user wants we allocated it. */
151                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
152                         return -ENOENT;
153                 prio = TC_H_MAKE(0x80000000U, 0U);
154         }
155
156         /* Find head of filter chain. */
157
158         /* Find link */
159         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
160         if (dev == NULL)
161                 return -ENODEV;
162
163         /* Find qdisc */
164         if (!parent) {
165                 q = dev->qdisc_sleeping;
166                 parent = q->handle;
167         } else {
168                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
169                 if (q == NULL)
170                         return -EINVAL;
171         }
172
173         /* Is it classful? */
174         if ((cops = q->ops->cl_ops) == NULL)
175                 return -EINVAL;
176
177         /* Do we search for filter, attached to class? */
178         if (TC_H_MIN(parent)) {
179                 cl = cops->get(q, parent);
180                 if (cl == 0)
181                         return -ENOENT;
182         }
183
184         /* And the last stroke */
185         chain = cops->tcf_chain(q, cl);
186         err = -EINVAL;
187         if (chain == NULL)
188                 goto errout;
189
190         /* Check the chain for existence of proto-tcf with this priority */
191         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
192                 if (tp->prio >= prio) {
193                         if (tp->prio == prio) {
194                                 if (!nprio || (tp->protocol != protocol && protocol))
195                                         goto errout;
196                         } else
197                                 tp = NULL;
198                         break;
199                 }
200         }
201
202         if (tp == NULL) {
203                 /* Proto-tcf does not exist, create new one */
204
205                 if (tca[TCA_KIND-1] == NULL || !protocol)
206                         goto errout;
207
208                 err = -ENOENT;
209                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
210                         goto errout;
211
212
213                 /* Create new proto tcf */
214
215                 err = -ENOBUFS;
216                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
217                 if (tp == NULL)
218                         goto errout;
219                 err = -EINVAL;
220                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND-1]);
221                 if (tp_ops == NULL) {
222 #ifdef CONFIG_KMOD
223                         struct rtattr *kind = tca[TCA_KIND-1];
224                         char name[IFNAMSIZ];
225
226                         if (kind != NULL &&
227                             rtattr_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
228                                 rtnl_unlock();
229                                 request_module("cls_%s", name);
230                                 rtnl_lock();
231                                 tp_ops = tcf_proto_lookup_ops(kind);
232                                 /* We dropped the RTNL semaphore in order to
233                                  * perform the module load.  So, even if we
234                                  * succeeded in loading the module we have to
235                                  * replay the request.  We indicate this using
236                                  * -EAGAIN.
237                                  */
238                                 if (tp_ops != NULL) {
239                                         module_put(tp_ops->owner);
240                                         err = -EAGAIN;
241                                 }
242                         }
243 #endif
244                         kfree(tp);
245                         goto errout;
246                 }
247                 tp->ops = tp_ops;
248                 tp->protocol = protocol;
249                 tp->prio = nprio ? : tcf_auto_prio(*back);
250                 tp->q = q;
251                 tp->classify = tp_ops->classify;
252                 tp->classid = parent;
253
254                 err = tp_ops->init(tp);
255                 if (err != 0) {
256                         module_put(tp_ops->owner);
257                         kfree(tp);
258                         goto errout;
259                 }
260
261                 qdisc_lock_tree(dev);
262                 tp->next = *back;
263                 *back = tp;
264                 qdisc_unlock_tree(dev);
265
266         } else if (tca[TCA_KIND-1] && rtattr_strcmp(tca[TCA_KIND-1], tp->ops->kind))
267                 goto errout;
268
269         fh = tp->ops->get(tp, t->tcm_handle);
270
271         if (fh == 0) {
272                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
273                         qdisc_lock_tree(dev);
274                         *back = tp->next;
275                         qdisc_unlock_tree(dev);
276
277                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
278                         tcf_destroy(tp);
279                         err = 0;
280                         goto errout;
281                 }
282
283                 err = -ENOENT;
284                 if (n->nlmsg_type != RTM_NEWTFILTER ||
285                     !(n->nlmsg_flags & NLM_F_CREATE))
286                         goto errout;
287         } else {
288                 switch (n->nlmsg_type) {
289                 case RTM_NEWTFILTER:
290                         err = -EEXIST;
291                         if (n->nlmsg_flags & NLM_F_EXCL)
292                                 goto errout;
293                         break;
294                 case RTM_DELTFILTER:
295                         err = tp->ops->delete(tp, fh);
296                         if (err == 0)
297                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
298                         goto errout;
299                 case RTM_GETTFILTER:
300                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
301                         goto errout;
302                 default:
303                         err = -EINVAL;
304                         goto errout;
305                 }
306         }
307
308         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
309         if (err == 0)
310                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
311
312 errout:
313         if (cl)
314                 cops->put(q, cl);
315         if (err == -EAGAIN)
316                 /* Replay the request. */
317                 goto replay;
318         return err;
319 }
320
321 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
322                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
323 {
324         struct tcmsg *tcm;
325         struct nlmsghdr  *nlh;
326         unsigned char *b = skb_tail_pointer(skb);
327
328         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
329         tcm = NLMSG_DATA(nlh);
330         tcm->tcm_family = AF_UNSPEC;
331         tcm->tcm__pad1 = 0;
332         tcm->tcm__pad1 = 0;
333         tcm->tcm_ifindex = tp->q->dev->ifindex;
334         tcm->tcm_parent = tp->classid;
335         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
336         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, tp->ops->kind);
337         tcm->tcm_handle = fh;
338         if (RTM_DELTFILTER != event) {
339                 tcm->tcm_handle = 0;
340                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
341                         goto rtattr_failure;
342         }
343         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
344         return skb->len;
345
346 nlmsg_failure:
347 rtattr_failure:
348         nlmsg_trim(skb, b);
349         return -1;
350 }
351
352 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
353                           struct tcf_proto *tp, unsigned long fh, int event)
354 {
355         struct sk_buff *skb;
356         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
357
358         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
359         if (!skb)
360                 return -ENOBUFS;
361
362         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
363                 kfree_skb(skb);
364                 return -EINVAL;
365         }
366
367         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
368                               n->nlmsg_flags & NLM_F_ECHO);
369 }
370
371 struct tcf_dump_args {
372         struct tcf_walker w;
373         struct sk_buff *skb;
374         struct netlink_callback *cb;
375 };
376
377 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
378                          struct tcf_walker *arg)
379 {
380         struct tcf_dump_args *a = (void *)arg;
381
382         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
383                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
384 }
385
386 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
387 {
388         struct net *net = skb->sk->sk_net;
389         int t;
390         int s_t;
391         struct net_device *dev;
392         struct Qdisc *q;
393         struct tcf_proto *tp, **chain;
394         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
395         unsigned long cl = 0;
396         const struct Qdisc_class_ops *cops;
397         struct tcf_dump_args arg;
398
399         if (net != &init_net)
400                 return 0;
401
402         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
403                 return skb->len;
404         if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
405                 return skb->len;
406
407         if (!tcm->tcm_parent)
408                 q = dev->qdisc_sleeping;
409         else
410                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
411         if (!q)
412                 goto out;
413         if ((cops = q->ops->cl_ops) == NULL)
414                 goto errout;
415         if (TC_H_MIN(tcm->tcm_parent)) {
416                 cl = cops->get(q, tcm->tcm_parent);
417                 if (cl == 0)
418                         goto errout;
419         }
420         chain = cops->tcf_chain(q, cl);
421         if (chain == NULL)
422                 goto errout;
423
424         s_t = cb->args[0];
425
426         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
427                 if (t < s_t) continue;
428                 if (TC_H_MAJ(tcm->tcm_info) &&
429                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
430                         continue;
431                 if (TC_H_MIN(tcm->tcm_info) &&
432                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
433                         continue;
434                 if (t > s_t)
435                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
436                 if (cb->args[1] == 0) {
437                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
438                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
439                                           RTM_NEWTFILTER) <= 0)
440                                 break;
441
442                         cb->args[1] = 1;
443                 }
444                 if (tp->ops->walk == NULL)
445                         continue;
446                 arg.w.fn = tcf_node_dump;
447                 arg.skb = skb;
448                 arg.cb = cb;
449                 arg.w.stop = 0;
450                 arg.w.skip = cb->args[1]-1;
451                 arg.w.count = 0;
452                 tp->ops->walk(tp, &arg.w);
453                 cb->args[1] = arg.w.count+1;
454                 if (arg.w.stop)
455                         break;
456         }
457
458         cb->args[0] = t;
459
460 errout:
461         if (cl)
462                 cops->put(q, cl);
463 out:
464         dev_put(dev);
465         return skb->len;
466 }
467
468 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
469 {
470 #ifdef CONFIG_NET_CLS_ACT
471         if (exts->action) {
472                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
473                 exts->action = NULL;
474         }
475 #endif
476 }
477 EXPORT_SYMBOL(tcf_exts_destroy);
478
479 int tcf_exts_validate(struct tcf_proto *tp, struct rtattr **tb,
480                   struct rtattr *rate_tlv, struct tcf_exts *exts,
481                   struct tcf_ext_map *map)
482 {
483         memset(exts, 0, sizeof(*exts));
484
485 #ifdef CONFIG_NET_CLS_ACT
486         {
487                 int err;
488                 struct tc_action *act;
489
490                 if (map->police && tb[map->police-1]) {
491                         act = tcf_action_init_1(tb[map->police-1], rate_tlv,
492                                                 "police", TCA_ACT_NOREPLACE,
493                                                 TCA_ACT_BIND, &err);
494                         if (act == NULL)
495                                 return err;
496
497                         act->type = TCA_OLD_COMPAT;
498                         exts->action = act;
499                 } else if (map->action && tb[map->action-1]) {
500                         act = tcf_action_init(tb[map->action-1], rate_tlv, NULL,
501                                 TCA_ACT_NOREPLACE, TCA_ACT_BIND, &err);
502                         if (act == NULL)
503                                 return err;
504
505                         exts->action = act;
506                 }
507         }
508 #else
509         if ((map->action && tb[map->action-1]) ||
510             (map->police && tb[map->police-1]))
511                 return -EOPNOTSUPP;
512 #endif
513
514         return 0;
515 }
516 EXPORT_SYMBOL(tcf_exts_validate);
517
518 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
519                      struct tcf_exts *src)
520 {
521 #ifdef CONFIG_NET_CLS_ACT
522         if (src->action) {
523                 struct tc_action *act;
524                 tcf_tree_lock(tp);
525                 act = xchg(&dst->action, src->action);
526                 tcf_tree_unlock(tp);
527                 if (act)
528                         tcf_action_destroy(act, TCA_ACT_UNBIND);
529         }
530 #endif
531 }
532 EXPORT_SYMBOL(tcf_exts_change);
533
534 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
535               struct tcf_ext_map *map)
536 {
537 #ifdef CONFIG_NET_CLS_ACT
538         if (map->action && exts->action) {
539                 /*
540                  * again for backward compatible mode - we want
541                  * to work with both old and new modes of entering
542                  * tc data even if iproute2  was newer - jhs
543                  */
544                 struct rtattr *p_rta = (struct rtattr *)skb_tail_pointer(skb);
545
546                 if (exts->action->type != TCA_OLD_COMPAT) {
547                         RTA_PUT(skb, map->action, 0, NULL);
548                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
549                                 goto rtattr_failure;
550                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
551                 } else if (map->police) {
552                         RTA_PUT(skb, map->police, 0, NULL);
553                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
554                                 goto rtattr_failure;
555                         p_rta->rta_len = skb_tail_pointer(skb) - (u8 *)p_rta;
556                 }
557         }
558 #endif
559         return 0;
560 rtattr_failure: __attribute__ ((unused))
561         return -1;
562 }
563 EXPORT_SYMBOL(tcf_exts_dump);
564
565
566 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
567                         struct tcf_ext_map *map)
568 {
569 #ifdef CONFIG_NET_CLS_ACT
570         if (exts->action)
571                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
572                         goto rtattr_failure;
573 #endif
574         return 0;
575 rtattr_failure: __attribute__ ((unused))
576         return -1;
577 }
578 EXPORT_SYMBOL(tcf_exts_dump_stats);
579
580 static int __init tc_filter_init(void)
581 {
582         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
583         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
584         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
585                                                  tc_dump_tfilter);
586
587         return 0;
588 }
589
590 subsys_initcall(tc_filter_init);