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