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
tcf_proto_lookup_ops(struct nlattr * kind)43 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
44 {
45 const 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
register_tcf_proto_ops(struct tcf_proto_ops * ops)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
unregister_tcf_proto_ops(struct tcf_proto_ops * ops)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
tcf_auto_prio(struct tcf_proto * tp)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
tc_ctl_tfilter(struct sk_buff * skb,struct nlmsghdr * n,void * arg)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 const 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 ||
153 !(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(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 cops = q->ops->cl_ops;
181 if (!cops)
182 return -EINVAL;
183
184 if (cops->tcf_chain == NULL)
185 return -EOPNOTSUPP;
186
187 /* Do we search for filter, attached to class? */
188 if (TC_H_MIN(parent)) {
189 cl = cops->get(q, parent);
190 if (cl == 0)
191 return -ENOENT;
192 }
193
194 /* And the last stroke */
195 chain = cops->tcf_chain(q, cl);
196 err = -EINVAL;
197 if (chain == NULL)
198 goto errout;
199
200 /* Check the chain for existence of proto-tcf with this priority */
201 for (back = chain; (tp = *back) != NULL; back = &tp->next) {
202 if (tp->prio >= prio) {
203 if (tp->prio == prio) {
204 if (!nprio ||
205 (tp->protocol != protocol && protocol))
206 goto errout;
207 } else
208 tp = NULL;
209 break;
210 }
211 }
212
213 root_lock = qdisc_root_sleeping_lock(q);
214
215 if (tp == NULL) {
216 /* Proto-tcf does not exist, create new one */
217
218 if (tca[TCA_KIND] == NULL || !protocol)
219 goto errout;
220
221 err = -ENOENT;
222 if (n->nlmsg_type != RTM_NEWTFILTER ||
223 !(n->nlmsg_flags & NLM_F_CREATE))
224 goto errout;
225
226
227 /* Create new proto tcf */
228
229 err = -ENOBUFS;
230 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
231 if (tp == NULL)
232 goto errout;
233 err = -ENOENT;
234 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
235 if (tp_ops == NULL) {
236 #ifdef CONFIG_MODULES
237 struct nlattr *kind = tca[TCA_KIND];
238 char name[IFNAMSIZ];
239
240 if (kind != NULL &&
241 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
242 rtnl_unlock();
243 request_module("cls_%s", name);
244 rtnl_lock();
245 tp_ops = tcf_proto_lookup_ops(kind);
246 /* We dropped the RTNL semaphore in order to
247 * perform the module load. So, even if we
248 * succeeded in loading the module we have to
249 * replay the request. We indicate this using
250 * -EAGAIN.
251 */
252 if (tp_ops != NULL) {
253 module_put(tp_ops->owner);
254 err = -EAGAIN;
255 }
256 }
257 #endif
258 kfree(tp);
259 goto errout;
260 }
261 tp->ops = tp_ops;
262 tp->protocol = protocol;
263 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
264 tp->q = q;
265 tp->classify = tp_ops->classify;
266 tp->classid = parent;
267
268 err = tp_ops->init(tp);
269 if (err != 0) {
270 module_put(tp_ops->owner);
271 kfree(tp);
272 goto errout;
273 }
274
275 tp_created = 1;
276
277 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
278 goto errout;
279
280 fh = tp->ops->get(tp, t->tcm_handle);
281
282 if (fh == 0) {
283 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
284 spin_lock_bh(root_lock);
285 *back = tp->next;
286 spin_unlock_bh(root_lock);
287
288 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
289 tcf_destroy(tp);
290 err = 0;
291 goto errout;
292 }
293
294 err = -ENOENT;
295 if (n->nlmsg_type != RTM_NEWTFILTER ||
296 !(n->nlmsg_flags & NLM_F_CREATE))
297 goto errout;
298 } else {
299 switch (n->nlmsg_type) {
300 case RTM_NEWTFILTER:
301 err = -EEXIST;
302 if (n->nlmsg_flags & NLM_F_EXCL) {
303 if (tp_created)
304 tcf_destroy(tp);
305 goto errout;
306 }
307 break;
308 case RTM_DELTFILTER:
309 err = tp->ops->delete(tp, fh);
310 if (err == 0)
311 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
312 goto errout;
313 case RTM_GETTFILTER:
314 err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
315 goto errout;
316 default:
317 err = -EINVAL;
318 goto errout;
319 }
320 }
321
322 err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
323 if (err == 0) {
324 if (tp_created) {
325 spin_lock_bh(root_lock);
326 tp->next = *back;
327 *back = tp;
328 spin_unlock_bh(root_lock);
329 }
330 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
331 } else {
332 if (tp_created)
333 tcf_destroy(tp);
334 }
335
336 errout:
337 if (cl)
338 cops->put(q, cl);
339 if (err == -EAGAIN)
340 /* Replay the request. */
341 goto replay;
342 return err;
343 }
344
tcf_fill_node(struct sk_buff * skb,struct tcf_proto * tp,unsigned long fh,u32 pid,u32 seq,u16 flags,int event)345 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
346 unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
347 {
348 struct tcmsg *tcm;
349 struct nlmsghdr *nlh;
350 unsigned char *b = skb_tail_pointer(skb);
351
352 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
353 tcm = NLMSG_DATA(nlh);
354 tcm->tcm_family = AF_UNSPEC;
355 tcm->tcm__pad1 = 0;
356 tcm->tcm__pad2 = 0;
357 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
358 tcm->tcm_parent = tp->classid;
359 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
360 NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
361 tcm->tcm_handle = fh;
362 if (RTM_DELTFILTER != event) {
363 tcm->tcm_handle = 0;
364 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
365 goto nla_put_failure;
366 }
367 nlh->nlmsg_len = skb_tail_pointer(skb) - b;
368 return skb->len;
369
370 nlmsg_failure:
371 nla_put_failure:
372 nlmsg_trim(skb, b);
373 return -1;
374 }
375
tfilter_notify(struct net * net,struct sk_buff * oskb,struct nlmsghdr * n,struct tcf_proto * tp,unsigned long fh,int event)376 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
377 struct nlmsghdr *n, struct tcf_proto *tp,
378 unsigned long fh, int event)
379 {
380 struct sk_buff *skb;
381 u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
382
383 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
384 if (!skb)
385 return -ENOBUFS;
386
387 if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
388 kfree_skb(skb);
389 return -EINVAL;
390 }
391
392 return rtnetlink_send(skb, net, pid, RTNLGRP_TC,
393 n->nlmsg_flags & NLM_F_ECHO);
394 }
395
396 struct tcf_dump_args {
397 struct tcf_walker w;
398 struct sk_buff *skb;
399 struct netlink_callback *cb;
400 };
401
tcf_node_dump(struct tcf_proto * tp,unsigned long n,struct tcf_walker * arg)402 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
403 struct tcf_walker *arg)
404 {
405 struct tcf_dump_args *a = (void *)arg;
406
407 return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
408 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
409 }
410
411 /* called with RTNL */
tc_dump_tfilter(struct sk_buff * skb,struct netlink_callback * cb)412 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
413 {
414 struct net *net = sock_net(skb->sk);
415 int t;
416 int s_t;
417 struct net_device *dev;
418 struct Qdisc *q;
419 struct tcf_proto *tp, **chain;
420 struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
421 unsigned long cl = 0;
422 const struct Qdisc_class_ops *cops;
423 struct tcf_dump_args arg;
424
425 if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
426 return skb->len;
427 dev = __dev_get_by_index(net, tcm->tcm_ifindex);
428 if (!dev)
429 return skb->len;
430
431 if (!tcm->tcm_parent)
432 q = dev->qdisc;
433 else
434 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
435 if (!q)
436 goto out;
437 cops = q->ops->cl_ops;
438 if (!cops)
439 goto errout;
440 if (cops->tcf_chain == NULL)
441 goto errout;
442 if (TC_H_MIN(tcm->tcm_parent)) {
443 cl = cops->get(q, tcm->tcm_parent);
444 if (cl == 0)
445 goto errout;
446 }
447 chain = cops->tcf_chain(q, cl);
448 if (chain == NULL)
449 goto errout;
450
451 s_t = cb->args[0];
452
453 for (tp = *chain, t = 0; tp; tp = tp->next, t++) {
454 if (t < s_t)
455 continue;
456 if (TC_H_MAJ(tcm->tcm_info) &&
457 TC_H_MAJ(tcm->tcm_info) != tp->prio)
458 continue;
459 if (TC_H_MIN(tcm->tcm_info) &&
460 TC_H_MIN(tcm->tcm_info) != tp->protocol)
461 continue;
462 if (t > s_t)
463 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
464 if (cb->args[1] == 0) {
465 if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
466 cb->nlh->nlmsg_seq, NLM_F_MULTI,
467 RTM_NEWTFILTER) <= 0)
468 break;
469
470 cb->args[1] = 1;
471 }
472 if (tp->ops->walk == NULL)
473 continue;
474 arg.w.fn = tcf_node_dump;
475 arg.skb = skb;
476 arg.cb = cb;
477 arg.w.stop = 0;
478 arg.w.skip = cb->args[1] - 1;
479 arg.w.count = 0;
480 tp->ops->walk(tp, &arg.w);
481 cb->args[1] = arg.w.count + 1;
482 if (arg.w.stop)
483 break;
484 }
485
486 cb->args[0] = t;
487
488 errout:
489 if (cl)
490 cops->put(q, cl);
491 out:
492 return skb->len;
493 }
494
tcf_exts_destroy(struct tcf_proto * tp,struct tcf_exts * exts)495 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
496 {
497 #ifdef CONFIG_NET_CLS_ACT
498 if (exts->action) {
499 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
500 exts->action = NULL;
501 }
502 #endif
503 }
504 EXPORT_SYMBOL(tcf_exts_destroy);
505
tcf_exts_validate(struct tcf_proto * tp,struct nlattr ** tb,struct nlattr * rate_tlv,struct tcf_exts * exts,const struct tcf_ext_map * map)506 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
507 struct nlattr *rate_tlv, struct tcf_exts *exts,
508 const struct tcf_ext_map *map)
509 {
510 memset(exts, 0, sizeof(*exts));
511
512 #ifdef CONFIG_NET_CLS_ACT
513 {
514 struct tc_action *act;
515
516 if (map->police && tb[map->police]) {
517 act = tcf_action_init_1(tb[map->police], rate_tlv,
518 "police", TCA_ACT_NOREPLACE,
519 TCA_ACT_BIND);
520 if (IS_ERR(act))
521 return PTR_ERR(act);
522
523 act->type = TCA_OLD_COMPAT;
524 exts->action = act;
525 } else if (map->action && tb[map->action]) {
526 act = tcf_action_init(tb[map->action], rate_tlv, NULL,
527 TCA_ACT_NOREPLACE, TCA_ACT_BIND);
528 if (IS_ERR(act))
529 return PTR_ERR(act);
530
531 exts->action = act;
532 }
533 }
534 #else
535 if ((map->action && tb[map->action]) ||
536 (map->police && tb[map->police]))
537 return -EOPNOTSUPP;
538 #endif
539
540 return 0;
541 }
542 EXPORT_SYMBOL(tcf_exts_validate);
543
tcf_exts_change(struct tcf_proto * tp,struct tcf_exts * dst,struct tcf_exts * src)544 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
545 struct tcf_exts *src)
546 {
547 #ifdef CONFIG_NET_CLS_ACT
548 if (src->action) {
549 struct tc_action *act;
550 tcf_tree_lock(tp);
551 act = dst->action;
552 dst->action = src->action;
553 tcf_tree_unlock(tp);
554 if (act)
555 tcf_action_destroy(act, TCA_ACT_UNBIND);
556 }
557 #endif
558 }
559 EXPORT_SYMBOL(tcf_exts_change);
560
tcf_exts_dump(struct sk_buff * skb,struct tcf_exts * exts,const struct tcf_ext_map * map)561 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
562 const struct tcf_ext_map *map)
563 {
564 #ifdef CONFIG_NET_CLS_ACT
565 if (map->action && exts->action) {
566 /*
567 * again for backward compatible mode - we want
568 * to work with both old and new modes of entering
569 * tc data even if iproute2 was newer - jhs
570 */
571 struct nlattr *nest;
572
573 if (exts->action->type != TCA_OLD_COMPAT) {
574 nest = nla_nest_start(skb, map->action);
575 if (nest == NULL)
576 goto nla_put_failure;
577 if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
578 goto nla_put_failure;
579 nla_nest_end(skb, nest);
580 } else if (map->police) {
581 nest = nla_nest_start(skb, map->police);
582 if (nest == NULL)
583 goto nla_put_failure;
584 if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
585 goto nla_put_failure;
586 nla_nest_end(skb, nest);
587 }
588 }
589 #endif
590 return 0;
591 nla_put_failure: __attribute__ ((unused))
592 return -1;
593 }
594 EXPORT_SYMBOL(tcf_exts_dump);
595
596
tcf_exts_dump_stats(struct sk_buff * skb,struct tcf_exts * exts,const struct tcf_ext_map * map)597 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
598 const struct tcf_ext_map *map)
599 {
600 #ifdef CONFIG_NET_CLS_ACT
601 if (exts->action)
602 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
603 goto nla_put_failure;
604 #endif
605 return 0;
606 nla_put_failure: __attribute__ ((unused))
607 return -1;
608 }
609 EXPORT_SYMBOL(tcf_exts_dump_stats);
610
tc_filter_init(void)611 static int __init tc_filter_init(void)
612 {
613 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL);
614 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL);
615 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
616 tc_dump_tfilter, NULL);
617
618 return 0;
619 }
620
621 subsys_initcall(tc_filter_init);
622