xref: /kernel/linux/linux-5.10/net/sched/cls_fw.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/cls_fw.c	Classifier mapping ipchains' fwmark to traffic class.
4 *
5 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 *
7 * Changes:
8 * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_walk off by one
9 * Karlis Peisenieks <karlis@mt.lv> : 990415 : fw_delete killed all the filter (and kernel).
10 * Alex <alex@pilotsoft.com> : 2004xxyy: Added Action extension
11 */
12
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/string.h>
18#include <linux/errno.h>
19#include <linux/skbuff.h>
20#include <net/netlink.h>
21#include <net/act_api.h>
22#include <net/pkt_cls.h>
23#include <net/sch_generic.h>
24
25#define HTSIZE 256
26
27struct fw_head {
28	u32			mask;
29	struct fw_filter __rcu	*ht[HTSIZE];
30	struct rcu_head		rcu;
31};
32
33struct fw_filter {
34	struct fw_filter __rcu	*next;
35	u32			id;
36	struct tcf_result	res;
37	int			ifindex;
38	struct tcf_exts		exts;
39	struct tcf_proto	*tp;
40	struct rcu_work		rwork;
41};
42
43static u32 fw_hash(u32 handle)
44{
45	handle ^= (handle >> 16);
46	handle ^= (handle >> 8);
47	return handle % HTSIZE;
48}
49
50static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
51		       struct tcf_result *res)
52{
53	struct fw_head *head = rcu_dereference_bh(tp->root);
54	struct fw_filter *f;
55	int r;
56	u32 id = skb->mark;
57
58	if (head != NULL) {
59		id &= head->mask;
60
61		for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
62		     f = rcu_dereference_bh(f->next)) {
63			if (f->id == id) {
64				*res = f->res;
65				if (!tcf_match_indev(skb, f->ifindex))
66					continue;
67				r = tcf_exts_exec(skb, &f->exts, res);
68				if (r < 0)
69					continue;
70
71				return r;
72			}
73		}
74	} else {
75		struct Qdisc *q = tcf_block_q(tp->chain->block);
76
77		/* Old method: classify the packet using its skb mark. */
78		if (id && (TC_H_MAJ(id) == 0 ||
79			   !(TC_H_MAJ(id ^ q->handle)))) {
80			res->classid = id;
81			res->class = 0;
82			return 0;
83		}
84	}
85
86	return -1;
87}
88
89static void *fw_get(struct tcf_proto *tp, u32 handle)
90{
91	struct fw_head *head = rtnl_dereference(tp->root);
92	struct fw_filter *f;
93
94	if (head == NULL)
95		return NULL;
96
97	f = rtnl_dereference(head->ht[fw_hash(handle)]);
98	for (; f; f = rtnl_dereference(f->next)) {
99		if (f->id == handle)
100			return f;
101	}
102	return NULL;
103}
104
105static int fw_init(struct tcf_proto *tp)
106{
107	/* We don't allocate fw_head here, because in the old method
108	 * we don't need it at all.
109	 */
110	return 0;
111}
112
113static void __fw_delete_filter(struct fw_filter *f)
114{
115	tcf_exts_destroy(&f->exts);
116	tcf_exts_put_net(&f->exts);
117	kfree(f);
118}
119
120static void fw_delete_filter_work(struct work_struct *work)
121{
122	struct fw_filter *f = container_of(to_rcu_work(work),
123					   struct fw_filter,
124					   rwork);
125	rtnl_lock();
126	__fw_delete_filter(f);
127	rtnl_unlock();
128}
129
130static void fw_destroy(struct tcf_proto *tp, bool rtnl_held,
131		       struct netlink_ext_ack *extack)
132{
133	struct fw_head *head = rtnl_dereference(tp->root);
134	struct fw_filter *f;
135	int h;
136
137	if (head == NULL)
138		return;
139
140	for (h = 0; h < HTSIZE; h++) {
141		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
142			RCU_INIT_POINTER(head->ht[h],
143					 rtnl_dereference(f->next));
144			tcf_unbind_filter(tp, &f->res);
145			if (tcf_exts_get_net(&f->exts))
146				tcf_queue_work(&f->rwork, fw_delete_filter_work);
147			else
148				__fw_delete_filter(f);
149		}
150	}
151	kfree_rcu(head, rcu);
152}
153
154static int fw_delete(struct tcf_proto *tp, void *arg, bool *last,
155		     bool rtnl_held, struct netlink_ext_ack *extack)
156{
157	struct fw_head *head = rtnl_dereference(tp->root);
158	struct fw_filter *f = arg;
159	struct fw_filter __rcu **fp;
160	struct fw_filter *pfp;
161	int ret = -EINVAL;
162	int h;
163
164	if (head == NULL || f == NULL)
165		goto out;
166
167	fp = &head->ht[fw_hash(f->id)];
168
169	for (pfp = rtnl_dereference(*fp); pfp;
170	     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
171		if (pfp == f) {
172			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
173			tcf_unbind_filter(tp, &f->res);
174			tcf_exts_get_net(&f->exts);
175			tcf_queue_work(&f->rwork, fw_delete_filter_work);
176			ret = 0;
177			break;
178		}
179	}
180
181	*last = true;
182	for (h = 0; h < HTSIZE; h++) {
183		if (rcu_access_pointer(head->ht[h])) {
184			*last = false;
185			break;
186		}
187	}
188
189out:
190	return ret;
191}
192
193static const struct nla_policy fw_policy[TCA_FW_MAX + 1] = {
194	[TCA_FW_CLASSID]	= { .type = NLA_U32 },
195	[TCA_FW_INDEV]		= { .type = NLA_STRING, .len = IFNAMSIZ },
196	[TCA_FW_MASK]		= { .type = NLA_U32 },
197};
198
199static int fw_set_parms(struct net *net, struct tcf_proto *tp,
200			struct fw_filter *f, struct nlattr **tb,
201			struct nlattr **tca, unsigned long base, bool ovr,
202			struct netlink_ext_ack *extack)
203{
204	struct fw_head *head = rtnl_dereference(tp->root);
205	u32 mask;
206	int err;
207
208	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &f->exts, ovr,
209				true, extack);
210	if (err < 0)
211		return err;
212
213	if (tb[TCA_FW_INDEV]) {
214		int ret;
215		ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack);
216		if (ret < 0)
217			return ret;
218		f->ifindex = ret;
219	}
220
221	err = -EINVAL;
222	if (tb[TCA_FW_MASK]) {
223		mask = nla_get_u32(tb[TCA_FW_MASK]);
224		if (mask != head->mask)
225			return err;
226	} else if (head->mask != 0xFFFFFFFF)
227		return err;
228
229	if (tb[TCA_FW_CLASSID]) {
230		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
231		tcf_bind_filter(tp, &f->res, base);
232	}
233
234	return 0;
235}
236
237static int fw_change(struct net *net, struct sk_buff *in_skb,
238		     struct tcf_proto *tp, unsigned long base,
239		     u32 handle, struct nlattr **tca, void **arg,
240		     bool ovr, bool rtnl_held,
241		     struct netlink_ext_ack *extack)
242{
243	struct fw_head *head = rtnl_dereference(tp->root);
244	struct fw_filter *f = *arg;
245	struct nlattr *opt = tca[TCA_OPTIONS];
246	struct nlattr *tb[TCA_FW_MAX + 1];
247	int err;
248
249	if (!opt)
250		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
251
252	err = nla_parse_nested_deprecated(tb, TCA_FW_MAX, opt, fw_policy,
253					  NULL);
254	if (err < 0)
255		return err;
256
257	if (f) {
258		struct fw_filter *pfp, *fnew;
259		struct fw_filter __rcu **fp;
260
261		if (f->id != handle && handle)
262			return -EINVAL;
263
264		fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
265		if (!fnew)
266			return -ENOBUFS;
267
268		fnew->id = f->id;
269		fnew->ifindex = f->ifindex;
270		fnew->tp = f->tp;
271
272		err = tcf_exts_init(&fnew->exts, net, TCA_FW_ACT,
273				    TCA_FW_POLICE);
274		if (err < 0) {
275			kfree(fnew);
276			return err;
277		}
278
279		err = fw_set_parms(net, tp, fnew, tb, tca, base, ovr, extack);
280		if (err < 0) {
281			tcf_exts_destroy(&fnew->exts);
282			kfree(fnew);
283			return err;
284		}
285
286		fp = &head->ht[fw_hash(fnew->id)];
287		for (pfp = rtnl_dereference(*fp); pfp;
288		     fp = &pfp->next, pfp = rtnl_dereference(*fp))
289			if (pfp == f)
290				break;
291
292		RCU_INIT_POINTER(fnew->next, rtnl_dereference(pfp->next));
293		rcu_assign_pointer(*fp, fnew);
294		tcf_unbind_filter(tp, &f->res);
295		tcf_exts_get_net(&f->exts);
296		tcf_queue_work(&f->rwork, fw_delete_filter_work);
297
298		*arg = fnew;
299		return err;
300	}
301
302	if (!handle)
303		return -EINVAL;
304
305	if (!head) {
306		u32 mask = 0xFFFFFFFF;
307		if (tb[TCA_FW_MASK])
308			mask = nla_get_u32(tb[TCA_FW_MASK]);
309
310		head = kzalloc(sizeof(*head), GFP_KERNEL);
311		if (!head)
312			return -ENOBUFS;
313		head->mask = mask;
314
315		rcu_assign_pointer(tp->root, head);
316	}
317
318	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
319	if (f == NULL)
320		return -ENOBUFS;
321
322	err = tcf_exts_init(&f->exts, net, TCA_FW_ACT, TCA_FW_POLICE);
323	if (err < 0)
324		goto errout;
325	f->id = handle;
326	f->tp = tp;
327
328	err = fw_set_parms(net, tp, f, tb, tca, base, ovr, extack);
329	if (err < 0)
330		goto errout;
331
332	RCU_INIT_POINTER(f->next, head->ht[fw_hash(handle)]);
333	rcu_assign_pointer(head->ht[fw_hash(handle)], f);
334
335	*arg = f;
336	return 0;
337
338errout:
339	tcf_exts_destroy(&f->exts);
340	kfree(f);
341	return err;
342}
343
344static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
345		    bool rtnl_held)
346{
347	struct fw_head *head = rtnl_dereference(tp->root);
348	int h;
349
350	if (head == NULL)
351		arg->stop = 1;
352
353	if (arg->stop)
354		return;
355
356	for (h = 0; h < HTSIZE; h++) {
357		struct fw_filter *f;
358
359		for (f = rtnl_dereference(head->ht[h]); f;
360		     f = rtnl_dereference(f->next)) {
361			if (arg->count < arg->skip) {
362				arg->count++;
363				continue;
364			}
365			if (arg->fn(tp, f, arg) < 0) {
366				arg->stop = 1;
367				return;
368			}
369			arg->count++;
370		}
371	}
372}
373
374static int fw_dump(struct net *net, struct tcf_proto *tp, void *fh,
375		   struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
376{
377	struct fw_head *head = rtnl_dereference(tp->root);
378	struct fw_filter *f = fh;
379	struct nlattr *nest;
380
381	if (f == NULL)
382		return skb->len;
383
384	t->tcm_handle = f->id;
385
386	if (!f->res.classid && !tcf_exts_has_actions(&f->exts))
387		return skb->len;
388
389	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
390	if (nest == NULL)
391		goto nla_put_failure;
392
393	if (f->res.classid &&
394	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
395		goto nla_put_failure;
396	if (f->ifindex) {
397		struct net_device *dev;
398		dev = __dev_get_by_index(net, f->ifindex);
399		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
400			goto nla_put_failure;
401	}
402	if (head->mask != 0xFFFFFFFF &&
403	    nla_put_u32(skb, TCA_FW_MASK, head->mask))
404		goto nla_put_failure;
405
406	if (tcf_exts_dump(skb, &f->exts) < 0)
407		goto nla_put_failure;
408
409	nla_nest_end(skb, nest);
410
411	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
412		goto nla_put_failure;
413
414	return skb->len;
415
416nla_put_failure:
417	nla_nest_cancel(skb, nest);
418	return -1;
419}
420
421static void fw_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
422			  unsigned long base)
423{
424	struct fw_filter *f = fh;
425
426	if (f && f->res.classid == classid) {
427		if (cl)
428			__tcf_bind_filter(q, &f->res, base);
429		else
430			__tcf_unbind_filter(q, &f->res);
431	}
432}
433
434static struct tcf_proto_ops cls_fw_ops __read_mostly = {
435	.kind		=	"fw",
436	.classify	=	fw_classify,
437	.init		=	fw_init,
438	.destroy	=	fw_destroy,
439	.get		=	fw_get,
440	.change		=	fw_change,
441	.delete		=	fw_delete,
442	.walk		=	fw_walk,
443	.dump		=	fw_dump,
444	.bind_class	=	fw_bind_class,
445	.owner		=	THIS_MODULE,
446};
447
448static int __init init_fw(void)
449{
450	return register_tcf_proto_ops(&cls_fw_ops);
451}
452
453static void __exit exit_fw(void)
454{
455	unregister_tcf_proto_ops(&cls_fw_ops);
456}
457
458module_init(init_fw)
459module_exit(exit_fw)
460MODULE_LICENSE("GPL");
461