Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[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 <linux/err.h>
27 #include <linux/slab.h>
28 #include <net/net_namespace.h>
29 #include <net/sock.h>
30 #include <net/netlink.h>
31 #include <net/pkt_sched.h>
32 #include <net/pkt_cls.h>
33
34 /* The list of all installed classifier types */
35
36 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
37
38 /* Protects list of registered TC modules. It is pure SMP lock. */
39 static DEFINE_RWLOCK(cls_mod_lock);
40
41 /* Find classifier type by string name */
42
43 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
44 {
45         struct tcf_proto_ops *t = NULL;
46
47         if (kind) {
48                 read_lock(&cls_mod_lock);
49                 for (t = tcf_proto_base; t; t = t->next) {
50                         if (nla_strcmp(kind, t->kind) == 0) {
51                                 if (!try_module_get(t->owner))
52                                         t = NULL;
53                                 break;
54                         }
55                 }
56                 read_unlock(&cls_mod_lock);
57         }
58         return t;
59 }
60
61 /* Register(unregister) new classifier type */
62
63 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
64 {
65         struct tcf_proto_ops *t, **tp;
66         int rc = -EEXIST;
67
68         write_lock(&cls_mod_lock);
69         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
70                 if (!strcmp(ops->kind, t->kind))
71                         goto out;
72
73         ops->next = NULL;
74         *tp = ops;
75         rc = 0;
76 out:
77         write_unlock(&cls_mod_lock);
78         return rc;
79 }
80 EXPORT_SYMBOL(register_tcf_proto_ops);
81
82 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
83 {
84         struct tcf_proto_ops *t, **tp;
85         int rc = -ENOENT;
86
87         write_lock(&cls_mod_lock);
88         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
89                 if (t == ops)
90                         break;
91
92         if (!t)
93                 goto out;
94         *tp = t->next;
95         rc = 0;
96 out:
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
107 /* Select new prio value from the range, managed by kernel. */
108
109 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
110 {
111         u32 first = TC_H_MAKE(0xC0000000U, 0U);
112
113         if (tp)
114                 first = tp->prio-1;
115
116         return first;
117 }
118
119 /* Add/change/delete/get a filter node */
120
121 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
122 {
123         struct net *net = sock_net(skb->sk);
124         struct nlattr *tca[TCA_MAX + 1];
125         spinlock_t *root_lock;
126         struct tcmsg *t;
127         u32 protocol;
128         u32 prio;
129         u32 nprio;
130         u32 parent;
131         struct net_device *dev;
132         struct Qdisc  *q;
133         struct tcf_proto **back, **chain;
134         struct tcf_proto *tp;
135         struct tcf_proto_ops *tp_ops;
136         const struct Qdisc_class_ops *cops;
137         unsigned long cl;
138         unsigned long fh;
139         int err;
140         int tp_created = 0;
141
142 replay:
143         t = NLMSG_DATA(n);
144         protocol = TC_H_MIN(t->tcm_info);
145         prio = TC_H_MAJ(t->tcm_info);
146         nprio = prio;
147         parent = t->tcm_parent;
148         cl = 0;
149
150         if (prio == 0) {
151                 /* If no priority is given, user wants we allocated it. */
152                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
153                         return -ENOENT;
154                 prio = TC_H_MAKE(0x80000000U, 0U);
155         }
156
157         /* Find head of filter chain. */
158
159         /* Find link */
160         dev = __dev_get_by_index(net, t->tcm_ifindex);
161         if (dev == NULL)
162                 return -ENODEV;
163
164         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
165         if (err < 0)
166                 return err;
167
168         /* Find qdisc */
169         if (!parent) {
170                 q = dev->qdisc;
171                 parent = q->handle;
172         } else {
173                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
174                 if (q == NULL)
175                         return -EINVAL;
176         }
177
178         /* Is it classful? */
179         if ((cops = q->ops->cl_ops) == NULL)
180                 return -EINVAL;
181
182         if (cops->tcf_chain == NULL)
183                 return -EOPNOTSUPP;
184
185         /* Do we search for filter, attached to class? */
186         if (TC_H_MIN(parent)) {
187                 cl = cops->get(q, parent);
188                 if (cl == 0)
189                         return -ENOENT;
190         }
191
192         /* And the last stroke */
193         chain = cops->tcf_chain(q, cl);
194         err = -EINVAL;
195         if (chain == NULL)
196                 goto errout;
197
198         /* Check the chain for existence of proto-tcf with this priority */
199         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
200                 if (tp->prio >= prio) {
201                         if (tp->prio == prio) {
202                                 if (!nprio || (tp->protocol != protocol && protocol))
203                                         goto errout;
204                         } else
205                                 tp = NULL;
206                         break;
207                 }
208         }
209
210         root_lock = qdisc_root_sleeping_lock(q);
211
212         if (tp == NULL) {
213                 /* Proto-tcf does not exist, create new one */
214
215                 if (tca[TCA_KIND] == NULL || !protocol)
216                         goto errout;
217
218                 err = -ENOENT;
219                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
220                         goto errout;
221
222
223                 /* Create new proto tcf */
224
225                 err = -ENOBUFS;
226                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
227                 if (tp == NULL)
228                         goto errout;
229                 err = -ENOENT;
230                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
231                 if (tp_ops == NULL) {
232 #ifdef CONFIG_MODULES
233                         struct nlattr *kind = tca[TCA_KIND];
234                         char name[IFNAMSIZ];
235
236                         if (kind != NULL &&
237                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
238                                 rtnl_unlock();
239                                 request_module("cls_%s", name);
240                                 rtnl_lock();
241                                 tp_ops = tcf_proto_lookup_ops(kind);
242                                 /* We dropped the RTNL semaphore in order to
243                                  * perform the module load.  So, even if we
244                                  * succeeded in loading the module we have to
245                                  * replay the request.  We indicate this using
246                                  * -EAGAIN.
247                                  */
248                                 if (tp_ops != NULL) {
249                                         module_put(tp_ops->owner);
250                                         err = -EAGAIN;
251                                 }
252                         }
253 #endif
254                         kfree(tp);
255                         goto errout;
256                 }
257                 tp->ops = tp_ops;
258                 tp->protocol = protocol;
259                 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
260                 tp->q = q;
261                 tp->classify = tp_ops->classify;
262                 tp->classid = parent;
263
264                 err = tp_ops->init(tp);
265                 if (err != 0) {
266                         module_put(tp_ops->owner);
267                         kfree(tp);
268                         goto errout;
269                 }
270
271                 tp_created = 1;
272
273         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
274                 goto errout;
275
276         fh = tp->ops->get(tp, t->tcm_handle);
277
278         if (fh == 0) {
279                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
280                         spin_lock_bh(root_lock);
281                         *back = tp->next;
282                         spin_unlock_bh(root_lock);
283
284                         tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
285                         tcf_destroy(tp);
286                         err = 0;
287                         goto errout;
288                 }
289
290                 err = -ENOENT;
291                 if (n->nlmsg_type != RTM_NEWTFILTER ||
292                     !(n->nlmsg_flags & NLM_F_CREATE))
293                         goto errout;
294         } else {
295                 switch (n->nlmsg_type) {
296                 case RTM_NEWTFILTER:
297                         err = -EEXIST;
298                         if (n->nlmsg_flags & NLM_F_EXCL) {
299                                 if (tp_created)
300                                         tcf_destroy(tp);
301                                 goto errout;
302                         }
303                         break;
304                 case RTM_DELTFILTER:
305                         err = tp->ops->delete(tp, fh);
306                         if (err == 0)
307                                 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
308                         goto errout;
309                 case RTM_GETTFILTER:
310                         err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
311                         goto errout;
312                 default:
313                         err = -EINVAL;
314                         goto errout;
315                 }
316         }
317
318         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
319         if (err == 0) {
320                 if (tp_created) {
321                         spin_lock_bh(root_lock);
322                         tp->next = *back;
323                         *back = tp;
324                         spin_unlock_bh(root_lock);
325                 }
326                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
327         } else {
328                 if (tp_created)
329                         tcf_destroy(tp);
330         }
331
332 errout:
333         if (cl)
334                 cops->put(q, cl);
335         if (err == -EAGAIN)
336                 /* Replay the request. */
337                 goto replay;
338         return err;
339 }
340
341 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
342                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
343 {
344         struct tcmsg *tcm;
345         struct nlmsghdr  *nlh;
346         unsigned char *b = skb_tail_pointer(skb);
347
348         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
349         tcm = NLMSG_DATA(nlh);
350         tcm->tcm_family = AF_UNSPEC;
351         tcm->tcm__pad1 = 0;
352         tcm->tcm__pad2 = 0;
353         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
354         tcm->tcm_parent = tp->classid;
355         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
356         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
357         tcm->tcm_handle = fh;
358         if (RTM_DELTFILTER != event) {
359                 tcm->tcm_handle = 0;
360                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
361                         goto nla_put_failure;
362         }
363         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
364         return skb->len;
365
366 nlmsg_failure:
367 nla_put_failure:
368         nlmsg_trim(skb, b);
369         return -1;
370 }
371
372 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
373                           struct nlmsghdr *n, struct tcf_proto *tp,
374                           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, 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 (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
422                 return skb->len;
423         if ((dev = __dev_get_by_index(net, tcm->tcm_ifindex)) == NULL)
424                 return skb->len;
425
426         if (!tcm->tcm_parent)
427                 q = dev->qdisc;
428         else
429                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
430         if (!q)
431                 goto out;
432         if ((cops = q->ops->cl_ops) == NULL)
433                 goto errout;
434         if (cops->tcf_chain == NULL)
435                 goto errout;
436         if (TC_H_MIN(tcm->tcm_parent)) {
437                 cl = cops->get(q, tcm->tcm_parent);
438                 if (cl == 0)
439                         goto errout;
440         }
441         chain = cops->tcf_chain(q, cl);
442         if (chain == NULL)
443                 goto errout;
444
445         s_t = cb->args[0];
446
447         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
448                 if (t < s_t) continue;
449                 if (TC_H_MAJ(tcm->tcm_info) &&
450                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
451                         continue;
452                 if (TC_H_MIN(tcm->tcm_info) &&
453                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
454                         continue;
455                 if (t > s_t)
456                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
457                 if (cb->args[1] == 0) {
458                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
459                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
460                                           RTM_NEWTFILTER) <= 0)
461                                 break;
462
463                         cb->args[1] = 1;
464                 }
465                 if (tp->ops->walk == NULL)
466                         continue;
467                 arg.w.fn = tcf_node_dump;
468                 arg.skb = skb;
469                 arg.cb = cb;
470                 arg.w.stop = 0;
471                 arg.w.skip = cb->args[1]-1;
472                 arg.w.count = 0;
473                 tp->ops->walk(tp, &arg.w);
474                 cb->args[1] = arg.w.count+1;
475                 if (arg.w.stop)
476                         break;
477         }
478
479         cb->args[0] = t;
480
481 errout:
482         if (cl)
483                 cops->put(q, cl);
484 out:
485         return skb->len;
486 }
487
488 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
489 {
490 #ifdef CONFIG_NET_CLS_ACT
491         if (exts->action) {
492                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
493                 exts->action = NULL;
494         }
495 #endif
496 }
497 EXPORT_SYMBOL(tcf_exts_destroy);
498
499 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
500                   struct nlattr *rate_tlv, struct tcf_exts *exts,
501                   const struct tcf_ext_map *map)
502 {
503         memset(exts, 0, sizeof(*exts));
504
505 #ifdef CONFIG_NET_CLS_ACT
506         {
507                 struct tc_action *act;
508
509                 if (map->police && tb[map->police]) {
510                         act = tcf_action_init_1(tb[map->police], rate_tlv,
511                                                 "police", TCA_ACT_NOREPLACE,
512                                                 TCA_ACT_BIND);
513                         if (IS_ERR(act))
514                                 return PTR_ERR(act);
515
516                         act->type = TCA_OLD_COMPAT;
517                         exts->action = act;
518                 } else if (map->action && tb[map->action]) {
519                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
520                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
521                         if (IS_ERR(act))
522                                 return PTR_ERR(act);
523
524                         exts->action = act;
525                 }
526         }
527 #else
528         if ((map->action && tb[map->action]) ||
529             (map->police && tb[map->police]))
530                 return -EOPNOTSUPP;
531 #endif
532
533         return 0;
534 }
535 EXPORT_SYMBOL(tcf_exts_validate);
536
537 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
538                      struct tcf_exts *src)
539 {
540 #ifdef CONFIG_NET_CLS_ACT
541         if (src->action) {
542                 struct tc_action *act;
543                 tcf_tree_lock(tp);
544                 act = dst->action;
545                 dst->action = src->action;
546                 tcf_tree_unlock(tp);
547                 if (act)
548                         tcf_action_destroy(act, TCA_ACT_UNBIND);
549         }
550 #endif
551 }
552 EXPORT_SYMBOL(tcf_exts_change);
553
554 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
555                   const struct tcf_ext_map *map)
556 {
557 #ifdef CONFIG_NET_CLS_ACT
558         if (map->action && exts->action) {
559                 /*
560                  * again for backward compatible mode - we want
561                  * to work with both old and new modes of entering
562                  * tc data even if iproute2  was newer - jhs
563                  */
564                 struct nlattr *nest;
565
566                 if (exts->action->type != TCA_OLD_COMPAT) {
567                         nest = nla_nest_start(skb, map->action);
568                         if (nest == NULL)
569                                 goto nla_put_failure;
570                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
571                                 goto nla_put_failure;
572                         nla_nest_end(skb, nest);
573                 } else if (map->police) {
574                         nest = nla_nest_start(skb, map->police);
575                         if (nest == NULL)
576                                 goto nla_put_failure;
577                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
578                                 goto nla_put_failure;
579                         nla_nest_end(skb, nest);
580                 }
581         }
582 #endif
583         return 0;
584 nla_put_failure: __attribute__ ((unused))
585         return -1;
586 }
587 EXPORT_SYMBOL(tcf_exts_dump);
588
589
590 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
591                         const struct tcf_ext_map *map)
592 {
593 #ifdef CONFIG_NET_CLS_ACT
594         if (exts->action)
595                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
596                         goto nla_put_failure;
597 #endif
598         return 0;
599 nla_put_failure: __attribute__ ((unused))
600         return -1;
601 }
602 EXPORT_SYMBOL(tcf_exts_dump_stats);
603
604 static int __init tc_filter_init(void)
605 {
606         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
607         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
608         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
609                                                  tc_dump_tfilter);
610
611         return 0;
612 }
613
614 subsys_initcall(tc_filter_init);