Commit | Line | Data |
---|---|---|
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; | |
30 | }; | |
31 | ||
32 | struct cls_bpf_prog { | |
7ae457c1 | 33 | struct bpf_prog *filter; |
7d1d65cb DB |
34 | struct sock_filter *bpf_ops; |
35 | struct tcf_exts exts; | |
36 | struct tcf_result res; | |
37 | struct list_head link; | |
38 | u32 handle; | |
39 | u16 bpf_len; | |
40 | }; | |
41 | ||
42 | static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = { | |
43 | [TCA_BPF_CLASSID] = { .type = NLA_U32 }, | |
44 | [TCA_BPF_OPS_LEN] = { .type = NLA_U16 }, | |
45 | [TCA_BPF_OPS] = { .type = NLA_BINARY, | |
46 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
47 | }; | |
48 | ||
7d1d65cb DB |
49 | static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, |
50 | struct tcf_result *res) | |
51 | { | |
52 | struct cls_bpf_head *head = tp->root; | |
53 | struct cls_bpf_prog *prog; | |
54 | int ret; | |
55 | ||
56 | list_for_each_entry(prog, &head->plist, link) { | |
7ae457c1 | 57 | int filter_res = BPF_PROG_RUN(prog->filter, skb); |
7d1d65cb DB |
58 | |
59 | if (filter_res == 0) | |
60 | continue; | |
61 | ||
62 | *res = prog->res; | |
63 | if (filter_res != -1) | |
64 | res->classid = filter_res; | |
65 | ||
66 | ret = tcf_exts_exec(skb, &prog->exts, res); | |
67 | if (ret < 0) | |
68 | continue; | |
69 | ||
70 | return ret; | |
71 | } | |
72 | ||
73 | return -1; | |
74 | } | |
75 | ||
76 | static int cls_bpf_init(struct tcf_proto *tp) | |
77 | { | |
78 | struct cls_bpf_head *head; | |
79 | ||
80 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
81 | if (head == NULL) | |
82 | return -ENOBUFS; | |
83 | ||
84 | INIT_LIST_HEAD(&head->plist); | |
85 | tp->root = head; | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog) | |
91 | { | |
92 | tcf_unbind_filter(tp, &prog->res); | |
93 | tcf_exts_destroy(tp, &prog->exts); | |
94 | ||
7ae457c1 | 95 | bpf_prog_destroy(prog->filter); |
7d1d65cb DB |
96 | |
97 | kfree(prog->bpf_ops); | |
98 | kfree(prog); | |
99 | } | |
100 | ||
101 | static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) | |
102 | { | |
103 | struct cls_bpf_head *head = tp->root; | |
104 | struct cls_bpf_prog *prog, *todel = (struct cls_bpf_prog *) arg; | |
105 | ||
106 | list_for_each_entry(prog, &head->plist, link) { | |
107 | if (prog == todel) { | |
108 | tcf_tree_lock(tp); | |
109 | list_del(&prog->link); | |
110 | tcf_tree_unlock(tp); | |
111 | ||
112 | cls_bpf_delete_prog(tp, prog); | |
113 | return 0; | |
114 | } | |
115 | } | |
116 | ||
117 | return -ENOENT; | |
118 | } | |
119 | ||
120 | static void cls_bpf_destroy(struct tcf_proto *tp) | |
121 | { | |
122 | struct cls_bpf_head *head = tp->root; | |
123 | struct cls_bpf_prog *prog, *tmp; | |
124 | ||
125 | list_for_each_entry_safe(prog, tmp, &head->plist, link) { | |
126 | list_del(&prog->link); | |
127 | cls_bpf_delete_prog(tp, prog); | |
128 | } | |
129 | ||
130 | kfree(head); | |
131 | } | |
132 | ||
133 | static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle) | |
134 | { | |
135 | struct cls_bpf_head *head = tp->root; | |
136 | struct cls_bpf_prog *prog; | |
137 | unsigned long ret = 0UL; | |
138 | ||
139 | if (head == NULL) | |
140 | return 0UL; | |
141 | ||
142 | list_for_each_entry(prog, &head->plist, link) { | |
143 | if (prog->handle == handle) { | |
144 | ret = (unsigned long) prog; | |
145 | break; | |
146 | } | |
147 | } | |
148 | ||
149 | return ret; | |
150 | } | |
151 | ||
152 | static void cls_bpf_put(struct tcf_proto *tp, unsigned long f) | |
153 | { | |
154 | } | |
155 | ||
156 | static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp, | |
157 | struct cls_bpf_prog *prog, | |
158 | unsigned long base, struct nlattr **tb, | |
2f7ef2f8 | 159 | struct nlattr *est, bool ovr) |
7d1d65cb DB |
160 | { |
161 | struct sock_filter *bpf_ops, *bpf_old; | |
162 | struct tcf_exts exts; | |
b1fcd35c | 163 | struct sock_fprog_kern tmp; |
7ae457c1 | 164 | struct bpf_prog *fp, *fp_old; |
7d1d65cb DB |
165 | u16 bpf_size, bpf_len; |
166 | u32 classid; | |
167 | int ret; | |
168 | ||
169 | if (!tb[TCA_BPF_OPS_LEN] || !tb[TCA_BPF_OPS] || !tb[TCA_BPF_CLASSID]) | |
170 | return -EINVAL; | |
171 | ||
5da57f42 | 172 | tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
2f7ef2f8 | 173 | ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr); |
7d1d65cb DB |
174 | if (ret < 0) |
175 | return ret; | |
176 | ||
177 | classid = nla_get_u32(tb[TCA_BPF_CLASSID]); | |
178 | bpf_len = nla_get_u16(tb[TCA_BPF_OPS_LEN]); | |
179 | if (bpf_len > BPF_MAXINSNS || bpf_len == 0) { | |
180 | ret = -EINVAL; | |
181 | goto errout; | |
182 | } | |
183 | ||
184 | bpf_size = bpf_len * sizeof(*bpf_ops); | |
185 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); | |
186 | if (bpf_ops == NULL) { | |
187 | ret = -ENOMEM; | |
188 | goto errout; | |
189 | } | |
190 | ||
191 | memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size); | |
192 | ||
193 | tmp.len = bpf_len; | |
b1fcd35c | 194 | tmp.filter = bpf_ops; |
7d1d65cb | 195 | |
7ae457c1 | 196 | ret = bpf_prog_create(&fp, &tmp); |
7d1d65cb DB |
197 | if (ret) |
198 | goto errout_free; | |
199 | ||
200 | tcf_tree_lock(tp); | |
201 | fp_old = prog->filter; | |
202 | bpf_old = prog->bpf_ops; | |
203 | ||
204 | prog->bpf_len = bpf_len; | |
205 | prog->bpf_ops = bpf_ops; | |
206 | prog->filter = fp; | |
207 | prog->res.classid = classid; | |
208 | tcf_tree_unlock(tp); | |
209 | ||
210 | tcf_bind_filter(tp, &prog->res, base); | |
211 | tcf_exts_change(tp, &prog->exts, &exts); | |
212 | ||
213 | if (fp_old) | |
7ae457c1 | 214 | bpf_prog_destroy(fp_old); |
7d1d65cb DB |
215 | if (bpf_old) |
216 | kfree(bpf_old); | |
217 | ||
218 | return 0; | |
219 | ||
220 | errout_free: | |
221 | kfree(bpf_ops); | |
222 | errout: | |
223 | tcf_exts_destroy(tp, &exts); | |
224 | return ret; | |
225 | } | |
226 | ||
227 | static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, | |
228 | struct cls_bpf_head *head) | |
229 | { | |
230 | unsigned int i = 0x80000000; | |
231 | ||
232 | do { | |
233 | if (++head->hgen == 0x7FFFFFFF) | |
234 | head->hgen = 1; | |
235 | } while (--i > 0 && cls_bpf_get(tp, head->hgen)); | |
236 | if (i == 0) | |
237 | pr_err("Insufficient number of handles\n"); | |
238 | ||
239 | return i; | |
240 | } | |
241 | ||
242 | static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, | |
243 | struct tcf_proto *tp, unsigned long base, | |
244 | u32 handle, struct nlattr **tca, | |
2f7ef2f8 | 245 | unsigned long *arg, bool ovr) |
7d1d65cb DB |
246 | { |
247 | struct cls_bpf_head *head = tp->root; | |
248 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) *arg; | |
249 | struct nlattr *tb[TCA_BPF_MAX + 1]; | |
250 | int ret; | |
251 | ||
252 | if (tca[TCA_OPTIONS] == NULL) | |
253 | return -EINVAL; | |
254 | ||
255 | ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy); | |
256 | if (ret < 0) | |
257 | return ret; | |
258 | ||
259 | if (prog != NULL) { | |
260 | if (handle && prog->handle != handle) | |
261 | return -EINVAL; | |
262 | return cls_bpf_modify_existing(net, tp, prog, base, tb, | |
2f7ef2f8 | 263 | tca[TCA_RATE], ovr); |
7d1d65cb DB |
264 | } |
265 | ||
266 | prog = kzalloc(sizeof(*prog), GFP_KERNEL); | |
267 | if (prog == NULL) | |
268 | return -ENOBUFS; | |
269 | ||
5da57f42 | 270 | tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
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 | ||
284 | tcf_tree_lock(tp); | |
285 | list_add(&prog->link, &head->plist); | |
286 | tcf_tree_unlock(tp); | |
287 | ||
288 | *arg = (unsigned long) prog; | |
289 | ||
290 | return 0; | |
291 | errout: | |
292 | if (*arg == 0UL && prog) | |
293 | kfree(prog); | |
294 | ||
295 | return ret; | |
296 | } | |
297 | ||
832d1d5b | 298 | static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, |
7d1d65cb DB |
299 | struct sk_buff *skb, struct tcmsg *tm) |
300 | { | |
301 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh; | |
302 | struct nlattr *nest, *nla; | |
303 | ||
304 | if (prog == NULL) | |
305 | return skb->len; | |
306 | ||
307 | tm->tcm_handle = prog->handle; | |
308 | ||
309 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
310 | if (nest == NULL) | |
311 | goto nla_put_failure; | |
312 | ||
313 | if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid)) | |
314 | goto nla_put_failure; | |
315 | if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_len)) | |
316 | goto nla_put_failure; | |
317 | ||
318 | nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_len * | |
319 | sizeof(struct sock_filter)); | |
320 | if (nla == NULL) | |
321 | goto nla_put_failure; | |
322 | ||
1fab9abc | 323 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); |
7d1d65cb | 324 | |
5da57f42 | 325 | if (tcf_exts_dump(skb, &prog->exts) < 0) |
7d1d65cb DB |
326 | goto nla_put_failure; |
327 | ||
328 | nla_nest_end(skb, nest); | |
329 | ||
5da57f42 | 330 | if (tcf_exts_dump_stats(skb, &prog->exts) < 0) |
7d1d65cb DB |
331 | goto nla_put_failure; |
332 | ||
333 | return skb->len; | |
334 | ||
335 | nla_put_failure: | |
336 | nla_nest_cancel(skb, nest); | |
337 | return -1; | |
338 | } | |
339 | ||
340 | static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
341 | { | |
342 | struct cls_bpf_head *head = tp->root; | |
343 | struct cls_bpf_prog *prog; | |
344 | ||
345 | list_for_each_entry(prog, &head->plist, link) { | |
346 | if (arg->count < arg->skip) | |
347 | goto skip; | |
348 | if (arg->fn(tp, (unsigned long) prog, arg) < 0) { | |
349 | arg->stop = 1; | |
350 | break; | |
351 | } | |
352 | skip: | |
353 | arg->count++; | |
354 | } | |
355 | } | |
356 | ||
357 | static struct tcf_proto_ops cls_bpf_ops __read_mostly = { | |
358 | .kind = "bpf", | |
359 | .owner = THIS_MODULE, | |
360 | .classify = cls_bpf_classify, | |
361 | .init = cls_bpf_init, | |
362 | .destroy = cls_bpf_destroy, | |
363 | .get = cls_bpf_get, | |
364 | .put = cls_bpf_put, | |
365 | .change = cls_bpf_change, | |
366 | .delete = cls_bpf_delete, | |
367 | .walk = cls_bpf_walk, | |
368 | .dump = cls_bpf_dump, | |
369 | }; | |
370 | ||
371 | static int __init cls_bpf_init_mod(void) | |
372 | { | |
373 | return register_tcf_proto_ops(&cls_bpf_ops); | |
374 | } | |
375 | ||
376 | static void __exit cls_bpf_exit_mod(void) | |
377 | { | |
378 | unregister_tcf_proto_ops(&cls_bpf_ops); | |
379 | } | |
380 | ||
381 | module_init(cls_bpf_init_mod); | |
382 | module_exit(cls_bpf_exit_mod); |