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Commit | Line | Data |
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7d1d65cb DB |
1 | /* |
2 | * Berkeley Packet Filter based traffic classifier | |
3 | * | |
4 | * Might be used to classify traffic through flexible, user-defined and | |
5 | * possibly JIT-ed BPF filters for traffic control as an alternative to | |
6 | * ematches. | |
7 | * | |
8 | * (C) 2013 Daniel Borkmann <dborkman@redhat.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/types.h> | |
17 | #include <linux/skbuff.h> | |
18 | #include <linux/filter.h> | |
19 | #include <net/rtnetlink.h> | |
20 | #include <net/pkt_cls.h> | |
21 | #include <net/sock.h> | |
22 | ||
23 | MODULE_LICENSE("GPL"); | |
24 | MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); | |
25 | MODULE_DESCRIPTION("TC BPF based classifier"); | |
26 | ||
27 | struct cls_bpf_head { | |
28 | struct list_head plist; | |
29 | u32 hgen; | |
1f947bf1 | 30 | struct rcu_head rcu; |
7d1d65cb DB |
31 | }; |
32 | ||
33 | struct cls_bpf_prog { | |
7ae457c1 | 34 | struct bpf_prog *filter; |
7d1d65cb DB |
35 | struct sock_filter *bpf_ops; |
36 | struct tcf_exts exts; | |
37 | struct tcf_result res; | |
38 | struct list_head link; | |
39 | u32 handle; | |
40 | u16 bpf_len; | |
1f947bf1 JF |
41 | struct tcf_proto *tp; |
42 | struct rcu_head rcu; | |
7d1d65cb DB |
43 | }; |
44 | ||
45 | static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = { | |
46 | [TCA_BPF_CLASSID] = { .type = NLA_U32 }, | |
47 | [TCA_BPF_OPS_LEN] = { .type = NLA_U16 }, | |
48 | [TCA_BPF_OPS] = { .type = NLA_BINARY, | |
49 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
50 | }; | |
51 | ||
7d1d65cb DB |
52 | static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, |
53 | struct tcf_result *res) | |
54 | { | |
80dcbd12 | 55 | struct cls_bpf_head *head = rcu_dereference_bh(tp->root); |
7d1d65cb DB |
56 | struct cls_bpf_prog *prog; |
57 | int ret; | |
58 | ||
1f947bf1 | 59 | list_for_each_entry_rcu(prog, &head->plist, link) { |
7ae457c1 | 60 | int filter_res = BPF_PROG_RUN(prog->filter, skb); |
7d1d65cb DB |
61 | |
62 | if (filter_res == 0) | |
63 | continue; | |
64 | ||
65 | *res = prog->res; | |
66 | if (filter_res != -1) | |
67 | res->classid = filter_res; | |
68 | ||
69 | ret = tcf_exts_exec(skb, &prog->exts, res); | |
70 | if (ret < 0) | |
71 | continue; | |
72 | ||
73 | return ret; | |
74 | } | |
75 | ||
76 | return -1; | |
77 | } | |
78 | ||
79 | static int cls_bpf_init(struct tcf_proto *tp) | |
80 | { | |
81 | struct cls_bpf_head *head; | |
82 | ||
83 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
84 | if (head == NULL) | |
85 | return -ENOBUFS; | |
86 | ||
1f947bf1 JF |
87 | INIT_LIST_HEAD_RCU(&head->plist); |
88 | rcu_assign_pointer(tp->root, head); | |
7d1d65cb DB |
89 | |
90 | return 0; | |
91 | } | |
92 | ||
93 | static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog) | |
94 | { | |
18d0264f | 95 | tcf_exts_destroy(&prog->exts); |
7d1d65cb | 96 | |
7ae457c1 | 97 | bpf_prog_destroy(prog->filter); |
7d1d65cb DB |
98 | |
99 | kfree(prog->bpf_ops); | |
100 | kfree(prog); | |
101 | } | |
102 | ||
1f947bf1 JF |
103 | static void __cls_bpf_delete_prog(struct rcu_head *rcu) |
104 | { | |
105 | struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu); | |
106 | ||
107 | cls_bpf_delete_prog(prog->tp, prog); | |
108 | } | |
109 | ||
7d1d65cb DB |
110 | static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) |
111 | { | |
1f947bf1 | 112 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
113 | struct cls_bpf_prog *prog, *todel = (struct cls_bpf_prog *) arg; |
114 | ||
115 | list_for_each_entry(prog, &head->plist, link) { | |
116 | if (prog == todel) { | |
1f947bf1 | 117 | list_del_rcu(&prog->link); |
18cdb37e | 118 | tcf_unbind_filter(tp, &prog->res); |
1f947bf1 | 119 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
7d1d65cb DB |
120 | return 0; |
121 | } | |
122 | } | |
123 | ||
124 | return -ENOENT; | |
125 | } | |
126 | ||
127 | static void cls_bpf_destroy(struct tcf_proto *tp) | |
128 | { | |
1f947bf1 | 129 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
130 | struct cls_bpf_prog *prog, *tmp; |
131 | ||
132 | list_for_each_entry_safe(prog, tmp, &head->plist, link) { | |
1f947bf1 | 133 | list_del_rcu(&prog->link); |
18cdb37e | 134 | tcf_unbind_filter(tp, &prog->res); |
1f947bf1 | 135 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
7d1d65cb DB |
136 | } |
137 | ||
1f947bf1 JF |
138 | RCU_INIT_POINTER(tp->root, NULL); |
139 | kfree_rcu(head, rcu); | |
7d1d65cb DB |
140 | } |
141 | ||
142 | static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle) | |
143 | { | |
1f947bf1 | 144 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
145 | struct cls_bpf_prog *prog; |
146 | unsigned long ret = 0UL; | |
147 | ||
148 | if (head == NULL) | |
149 | return 0UL; | |
150 | ||
1f947bf1 | 151 | list_for_each_entry_rcu(prog, &head->plist, link) { |
7d1d65cb DB |
152 | if (prog->handle == handle) { |
153 | ret = (unsigned long) prog; | |
154 | break; | |
155 | } | |
156 | } | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | static void cls_bpf_put(struct tcf_proto *tp, unsigned long f) | |
162 | { | |
163 | } | |
164 | ||
165 | static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp, | |
166 | struct cls_bpf_prog *prog, | |
167 | unsigned long base, struct nlattr **tb, | |
2f7ef2f8 | 168 | struct nlattr *est, bool ovr) |
7d1d65cb | 169 | { |
1f947bf1 | 170 | struct sock_filter *bpf_ops; |
7d1d65cb | 171 | struct tcf_exts exts; |
b1fcd35c | 172 | struct sock_fprog_kern tmp; |
1f947bf1 | 173 | struct bpf_prog *fp; |
7d1d65cb DB |
174 | u16 bpf_size, bpf_len; |
175 | u32 classid; | |
176 | int ret; | |
177 | ||
178 | if (!tb[TCA_BPF_OPS_LEN] || !tb[TCA_BPF_OPS] || !tb[TCA_BPF_CLASSID]) | |
179 | return -EINVAL; | |
180 | ||
5da57f42 | 181 | tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
2f7ef2f8 | 182 | ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr); |
7d1d65cb DB |
183 | if (ret < 0) |
184 | return ret; | |
185 | ||
186 | classid = nla_get_u32(tb[TCA_BPF_CLASSID]); | |
187 | bpf_len = nla_get_u16(tb[TCA_BPF_OPS_LEN]); | |
188 | if (bpf_len > BPF_MAXINSNS || bpf_len == 0) { | |
189 | ret = -EINVAL; | |
190 | goto errout; | |
191 | } | |
192 | ||
193 | bpf_size = bpf_len * sizeof(*bpf_ops); | |
194 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); | |
195 | if (bpf_ops == NULL) { | |
196 | ret = -ENOMEM; | |
197 | goto errout; | |
198 | } | |
199 | ||
200 | memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size); | |
201 | ||
202 | tmp.len = bpf_len; | |
b1fcd35c | 203 | tmp.filter = bpf_ops; |
7d1d65cb | 204 | |
7ae457c1 | 205 | ret = bpf_prog_create(&fp, &tmp); |
7d1d65cb DB |
206 | if (ret) |
207 | goto errout_free; | |
208 | ||
7d1d65cb DB |
209 | prog->bpf_len = bpf_len; |
210 | prog->bpf_ops = bpf_ops; | |
211 | prog->filter = fp; | |
212 | prog->res.classid = classid; | |
7d1d65cb DB |
213 | |
214 | tcf_bind_filter(tp, &prog->res, base); | |
215 | tcf_exts_change(tp, &prog->exts, &exts); | |
216 | ||
7d1d65cb | 217 | return 0; |
7d1d65cb DB |
218 | errout_free: |
219 | kfree(bpf_ops); | |
220 | errout: | |
18d0264f | 221 | tcf_exts_destroy(&exts); |
7d1d65cb DB |
222 | return ret; |
223 | } | |
224 | ||
225 | static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, | |
226 | struct cls_bpf_head *head) | |
227 | { | |
228 | unsigned int i = 0x80000000; | |
229 | ||
230 | do { | |
231 | if (++head->hgen == 0x7FFFFFFF) | |
232 | head->hgen = 1; | |
233 | } while (--i > 0 && cls_bpf_get(tp, head->hgen)); | |
234 | if (i == 0) | |
235 | pr_err("Insufficient number of handles\n"); | |
236 | ||
237 | return i; | |
238 | } | |
239 | ||
240 | static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, | |
241 | struct tcf_proto *tp, unsigned long base, | |
242 | u32 handle, struct nlattr **tca, | |
2f7ef2f8 | 243 | unsigned long *arg, bool ovr) |
7d1d65cb | 244 | { |
1f947bf1 JF |
245 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
246 | struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg; | |
7d1d65cb | 247 | struct nlattr *tb[TCA_BPF_MAX + 1]; |
1f947bf1 | 248 | struct cls_bpf_prog *prog; |
7d1d65cb DB |
249 | int ret; |
250 | ||
251 | if (tca[TCA_OPTIONS] == NULL) | |
252 | return -EINVAL; | |
253 | ||
254 | ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy); | |
255 | if (ret < 0) | |
256 | return ret; | |
257 | ||
7d1d65cb | 258 | prog = kzalloc(sizeof(*prog), GFP_KERNEL); |
1f947bf1 | 259 | if (!prog) |
7d1d65cb DB |
260 | return -ENOBUFS; |
261 | ||
5da57f42 | 262 | tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
1f947bf1 JF |
263 | |
264 | if (oldprog) { | |
265 | if (handle && oldprog->handle != handle) { | |
266 | ret = -EINVAL; | |
267 | goto errout; | |
268 | } | |
269 | } | |
270 | ||
7d1d65cb DB |
271 | if (handle == 0) |
272 | prog->handle = cls_bpf_grab_new_handle(tp, head); | |
273 | else | |
274 | prog->handle = handle; | |
275 | if (prog->handle == 0) { | |
276 | ret = -EINVAL; | |
277 | goto errout; | |
278 | } | |
279 | ||
2f7ef2f8 | 280 | ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr); |
7d1d65cb DB |
281 | if (ret < 0) |
282 | goto errout; | |
283 | ||
1f947bf1 JF |
284 | if (oldprog) { |
285 | list_replace_rcu(&prog->link, &oldprog->link); | |
18cdb37e | 286 | tcf_unbind_filter(tp, &oldprog->res); |
1f947bf1 JF |
287 | call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); |
288 | } else { | |
289 | list_add_rcu(&prog->link, &head->plist); | |
290 | } | |
7d1d65cb DB |
291 | |
292 | *arg = (unsigned long) prog; | |
7d1d65cb DB |
293 | return 0; |
294 | errout: | |
1f947bf1 | 295 | kfree(prog); |
7d1d65cb DB |
296 | |
297 | return ret; | |
298 | } | |
299 | ||
832d1d5b | 300 | static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, |
7d1d65cb DB |
301 | struct sk_buff *skb, struct tcmsg *tm) |
302 | { | |
303 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh; | |
304 | struct nlattr *nest, *nla; | |
305 | ||
306 | if (prog == NULL) | |
307 | return skb->len; | |
308 | ||
309 | tm->tcm_handle = prog->handle; | |
310 | ||
311 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
312 | if (nest == NULL) | |
313 | goto nla_put_failure; | |
314 | ||
315 | if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid)) | |
316 | goto nla_put_failure; | |
317 | if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_len)) | |
318 | goto nla_put_failure; | |
319 | ||
320 | nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_len * | |
321 | sizeof(struct sock_filter)); | |
322 | if (nla == NULL) | |
323 | goto nla_put_failure; | |
324 | ||
1fab9abc | 325 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); |
7d1d65cb | 326 | |
5da57f42 | 327 | if (tcf_exts_dump(skb, &prog->exts) < 0) |
7d1d65cb DB |
328 | goto nla_put_failure; |
329 | ||
330 | nla_nest_end(skb, nest); | |
331 | ||
5da57f42 | 332 | if (tcf_exts_dump_stats(skb, &prog->exts) < 0) |
7d1d65cb DB |
333 | goto nla_put_failure; |
334 | ||
335 | return skb->len; | |
336 | ||
337 | nla_put_failure: | |
338 | nla_nest_cancel(skb, nest); | |
339 | return -1; | |
340 | } | |
341 | ||
342 | static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
343 | { | |
1f947bf1 | 344 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
345 | struct cls_bpf_prog *prog; |
346 | ||
1f947bf1 | 347 | list_for_each_entry_rcu(prog, &head->plist, link) { |
7d1d65cb DB |
348 | if (arg->count < arg->skip) |
349 | goto skip; | |
350 | if (arg->fn(tp, (unsigned long) prog, arg) < 0) { | |
351 | arg->stop = 1; | |
352 | break; | |
353 | } | |
354 | skip: | |
355 | arg->count++; | |
356 | } | |
357 | } | |
358 | ||
359 | static struct tcf_proto_ops cls_bpf_ops __read_mostly = { | |
360 | .kind = "bpf", | |
361 | .owner = THIS_MODULE, | |
362 | .classify = cls_bpf_classify, | |
363 | .init = cls_bpf_init, | |
364 | .destroy = cls_bpf_destroy, | |
365 | .get = cls_bpf_get, | |
366 | .put = cls_bpf_put, | |
367 | .change = cls_bpf_change, | |
368 | .delete = cls_bpf_delete, | |
369 | .walk = cls_bpf_walk, | |
370 | .dump = cls_bpf_dump, | |
371 | }; | |
372 | ||
373 | static int __init cls_bpf_init_mod(void) | |
374 | { | |
375 | return register_tcf_proto_ops(&cls_bpf_ops); | |
376 | } | |
377 | ||
378 | static void __exit cls_bpf_exit_mod(void) | |
379 | { | |
380 | unregister_tcf_proto_ops(&cls_bpf_ops); | |
381 | } | |
382 | ||
383 | module_init(cls_bpf_init_mod); | |
384 | module_exit(cls_bpf_exit_mod); |