xref: /linux/net/sched/cls_basic.c (revision 7ff836f064e2c814a7504c91a4464eea45d475bd) 
1 /*
2  * net/sched/cls_basic.c	Basic Packet Classifier.
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:	Thomas Graf <tgraf@suug.ch>
10  */
11 
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/skbuff.h>
20 #include <linux/idr.h>
21 #include <linux/percpu.h>
22 #include <net/netlink.h>
23 #include <net/act_api.h>
24 #include <net/pkt_cls.h>
25 
26 struct basic_head {
27 	struct list_head	flist;
28 	struct idr		handle_idr;
29 	struct rcu_head		rcu;
30 };
31 
32 struct basic_filter {
33 	u32			handle;
34 	struct tcf_exts		exts;
35 	struct tcf_ematch_tree	ematches;
36 	struct tcf_result	res;
37 	struct tcf_proto	*tp;
38 	struct list_head	link;
39 	struct tc_basic_pcnt __percpu *pf;
40 	struct rcu_work		rwork;
41 };
42 
43 static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
44 			  struct tcf_result *res)
45 {
46 	int r;
47 	struct basic_head *head = rcu_dereference_bh(tp->root);
48 	struct basic_filter *f;
49 
50 	list_for_each_entry_rcu(f, &head->flist, link) {
51 		__this_cpu_inc(f->pf->rcnt);
52 		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
53 			continue;
54 		__this_cpu_inc(f->pf->rhit);
55 		*res = f->res;
56 		r = tcf_exts_exec(skb, &f->exts, res);
57 		if (r < 0)
58 			continue;
59 		return r;
60 	}
61 	return -1;
62 }
63 
64 static void *basic_get(struct tcf_proto *tp, u32 handle)
65 {
66 	struct basic_head *head = rtnl_dereference(tp->root);
67 	struct basic_filter *f;
68 
69 	list_for_each_entry(f, &head->flist, link) {
70 		if (f->handle == handle) {
71 			return f;
72 		}
73 	}
74 
75 	return NULL;
76 }
77 
78 static int basic_init(struct tcf_proto *tp)
79 {
80 	struct basic_head *head;
81 
82 	head = kzalloc(sizeof(*head), GFP_KERNEL);
83 	if (head == NULL)
84 		return -ENOBUFS;
85 	INIT_LIST_HEAD(&head->flist);
86 	idr_init(&head->handle_idr);
87 	rcu_assign_pointer(tp->root, head);
88 	return 0;
89 }
90 
91 static void __basic_delete_filter(struct basic_filter *f)
92 {
93 	tcf_exts_destroy(&f->exts);
94 	tcf_em_tree_destroy(&f->ematches);
95 	tcf_exts_put_net(&f->exts);
96 	free_percpu(f->pf);
97 	kfree(f);
98 }
99 
100 static void basic_delete_filter_work(struct work_struct *work)
101 {
102 	struct basic_filter *f = container_of(to_rcu_work(work),
103 					      struct basic_filter,
104 					      rwork);
105 	rtnl_lock();
106 	__basic_delete_filter(f);
107 	rtnl_unlock();
108 }
109 
110 static void basic_destroy(struct tcf_proto *tp, bool rtnl_held,
111 			  struct netlink_ext_ack *extack)
112 {
113 	struct basic_head *head = rtnl_dereference(tp->root);
114 	struct basic_filter *f, *n;
115 
116 	list_for_each_entry_safe(f, n, &head->flist, link) {
117 		list_del_rcu(&f->link);
118 		tcf_unbind_filter(tp, &f->res);
119 		idr_remove(&head->handle_idr, f->handle);
120 		if (tcf_exts_get_net(&f->exts))
121 			tcf_queue_work(&f->rwork, basic_delete_filter_work);
122 		else
123 			__basic_delete_filter(f);
124 	}
125 	idr_destroy(&head->handle_idr);
126 	kfree_rcu(head, rcu);
127 }
128 
129 static int basic_delete(struct tcf_proto *tp, void *arg, bool *last,
130 			bool rtnl_held, struct netlink_ext_ack *extack)
131 {
132 	struct basic_head *head = rtnl_dereference(tp->root);
133 	struct basic_filter *f = arg;
134 
135 	list_del_rcu(&f->link);
136 	tcf_unbind_filter(tp, &f->res);
137 	idr_remove(&head->handle_idr, f->handle);
138 	tcf_exts_get_net(&f->exts);
139 	tcf_queue_work(&f->rwork, basic_delete_filter_work);
140 	*last = list_empty(&head->flist);
141 	return 0;
142 }
143 
144 static const struct nla_policy basic_policy[TCA_BASIC_MAX + 1] = {
145 	[TCA_BASIC_CLASSID]	= { .type = NLA_U32 },
146 	[TCA_BASIC_EMATCHES]	= { .type = NLA_NESTED },
147 };
148 
149 static int basic_set_parms(struct net *net, struct tcf_proto *tp,
150 			   struct basic_filter *f, unsigned long base,
151 			   struct nlattr **tb,
152 			   struct nlattr *est, bool ovr,
153 			   struct netlink_ext_ack *extack)
154 {
155 	int err;
156 
157 	err = tcf_exts_validate(net, tp, tb, est, &f->exts, ovr, true, extack);
158 	if (err < 0)
159 		return err;
160 
161 	err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES], &f->ematches);
162 	if (err < 0)
163 		return err;
164 
165 	if (tb[TCA_BASIC_CLASSID]) {
166 		f->res.classid = nla_get_u32(tb[TCA_BASIC_CLASSID]);
167 		tcf_bind_filter(tp, &f->res, base);
168 	}
169 
170 	f->tp = tp;
171 	return 0;
172 }
173 
174 static int basic_change(struct net *net, struct sk_buff *in_skb,
175 			struct tcf_proto *tp, unsigned long base, u32 handle,
176 			struct nlattr **tca, void **arg, bool ovr,
177 			bool rtnl_held, struct netlink_ext_ack *extack)
178 {
179 	int err;
180 	struct basic_head *head = rtnl_dereference(tp->root);
181 	struct nlattr *tb[TCA_BASIC_MAX + 1];
182 	struct basic_filter *fold = (struct basic_filter *) *arg;
183 	struct basic_filter *fnew;
184 
185 	if (tca[TCA_OPTIONS] == NULL)
186 		return -EINVAL;
187 
188 	err = nla_parse_nested_deprecated(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS],
189 					  basic_policy, NULL);
190 	if (err < 0)
191 		return err;
192 
193 	if (fold != NULL) {
194 		if (handle && fold->handle != handle)
195 			return -EINVAL;
196 	}
197 
198 	fnew = kzalloc(sizeof(*fnew), GFP_KERNEL);
199 	if (!fnew)
200 		return -ENOBUFS;
201 
202 	err = tcf_exts_init(&fnew->exts, net, TCA_BASIC_ACT, TCA_BASIC_POLICE);
203 	if (err < 0)
204 		goto errout;
205 
206 	if (!handle) {
207 		handle = 1;
208 		err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
209 				    INT_MAX, GFP_KERNEL);
210 	} else if (!fold) {
211 		err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
212 				    handle, GFP_KERNEL);
213 	}
214 	if (err)
215 		goto errout;
216 	fnew->handle = handle;
217 	fnew->pf = alloc_percpu(struct tc_basic_pcnt);
218 	if (!fnew->pf) {
219 		err = -ENOMEM;
220 		goto errout;
221 	}
222 
223 	err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr,
224 			      extack);
225 	if (err < 0) {
226 		if (!fold)
227 			idr_remove(&head->handle_idr, fnew->handle);
228 		goto errout;
229 	}
230 
231 	*arg = fnew;
232 
233 	if (fold) {
234 		idr_replace(&head->handle_idr, fnew, fnew->handle);
235 		list_replace_rcu(&fold->link, &fnew->link);
236 		tcf_unbind_filter(tp, &fold->res);
237 		tcf_exts_get_net(&fold->exts);
238 		tcf_queue_work(&fold->rwork, basic_delete_filter_work);
239 	} else {
240 		list_add_rcu(&fnew->link, &head->flist);
241 	}
242 
243 	return 0;
244 errout:
245 	free_percpu(fnew->pf);
246 	tcf_exts_destroy(&fnew->exts);
247 	kfree(fnew);
248 	return err;
249 }
250 
251 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg,
252 		       bool rtnl_held)
253 {
254 	struct basic_head *head = rtnl_dereference(tp->root);
255 	struct basic_filter *f;
256 
257 	list_for_each_entry(f, &head->flist, link) {
258 		if (arg->count < arg->skip)
259 			goto skip;
260 
261 		if (arg->fn(tp, f, arg) < 0) {
262 			arg->stop = 1;
263 			break;
264 		}
265 skip:
266 		arg->count++;
267 	}
268 }
269 
270 static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
271 {
272 	struct basic_filter *f = fh;
273 
274 	if (f && f->res.classid == classid)
275 		f->res.class = cl;
276 }
277 
278 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
279 		      struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
280 {
281 	struct tc_basic_pcnt gpf = {};
282 	struct basic_filter *f = fh;
283 	struct nlattr *nest;
284 	int cpu;
285 
286 	if (f == NULL)
287 		return skb->len;
288 
289 	t->tcm_handle = f->handle;
290 
291 	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
292 	if (nest == NULL)
293 		goto nla_put_failure;
294 
295 	if (f->res.classid &&
296 	    nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
297 		goto nla_put_failure;
298 
299 	for_each_possible_cpu(cpu) {
300 		struct tc_basic_pcnt *pf = per_cpu_ptr(f->pf, cpu);
301 
302 		gpf.rcnt += pf->rcnt;
303 		gpf.rhit += pf->rhit;
304 	}
305 
306 	if (nla_put_64bit(skb, TCA_BASIC_PCNT,
307 			  sizeof(struct tc_basic_pcnt),
308 			  &gpf, TCA_BASIC_PAD))
309 		goto nla_put_failure;
310 
311 	if (tcf_exts_dump(skb, &f->exts) < 0 ||
312 	    tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
313 		goto nla_put_failure;
314 
315 	nla_nest_end(skb, nest);
316 
317 	if (tcf_exts_dump_stats(skb, &f->exts) < 0)
318 		goto nla_put_failure;
319 
320 	return skb->len;
321 
322 nla_put_failure:
323 	nla_nest_cancel(skb, nest);
324 	return -1;
325 }
326 
327 static struct tcf_proto_ops cls_basic_ops __read_mostly = {
328 	.kind		=	"basic",
329 	.classify	=	basic_classify,
330 	.init		=	basic_init,
331 	.destroy	=	basic_destroy,
332 	.get		=	basic_get,
333 	.change		=	basic_change,
334 	.delete		=	basic_delete,
335 	.walk		=	basic_walk,
336 	.dump		=	basic_dump,
337 	.bind_class	=	basic_bind_class,
338 	.owner		=	THIS_MODULE,
339 };
340 
341 static int __init init_basic(void)
342 {
343 	return register_tcf_proto_ops(&cls_basic_ops);
344 }
345 
346 static void __exit exit_basic(void)
347 {
348 	unregister_tcf_proto_ops(&cls_basic_ops);
349 }
350 
351 module_init(init_basic)
352 module_exit(exit_basic)
353 MODULE_LICENSE("GPL");
354