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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> | |
e2e9b654 DB |
19 | #include <linux/bpf.h> |
20 | ||
7d1d65cb DB |
21 | #include <net/rtnetlink.h> |
22 | #include <net/pkt_cls.h> | |
23 | #include <net/sock.h> | |
24 | ||
25 | MODULE_LICENSE("GPL"); | |
26 | MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>"); | |
27 | MODULE_DESCRIPTION("TC BPF based classifier"); | |
28 | ||
e2e9b654 DB |
29 | #define CLS_BPF_NAME_LEN 256 |
30 | ||
7d1d65cb DB |
31 | struct cls_bpf_head { |
32 | struct list_head plist; | |
33 | u32 hgen; | |
1f947bf1 | 34 | struct rcu_head rcu; |
7d1d65cb DB |
35 | }; |
36 | ||
37 | struct cls_bpf_prog { | |
7ae457c1 | 38 | struct bpf_prog *filter; |
7d1d65cb | 39 | struct list_head link; |
e2e9b654 DB |
40 | struct tcf_result res; |
41 | struct tcf_exts exts; | |
7d1d65cb | 42 | u32 handle; |
e2e9b654 DB |
43 | union { |
44 | u32 bpf_fd; | |
45 | u16 bpf_num_ops; | |
46 | }; | |
47 | struct sock_filter *bpf_ops; | |
48 | const char *bpf_name; | |
1f947bf1 JF |
49 | struct tcf_proto *tp; |
50 | struct rcu_head rcu; | |
7d1d65cb DB |
51 | }; |
52 | ||
53 | static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = { | |
54 | [TCA_BPF_CLASSID] = { .type = NLA_U32 }, | |
e2e9b654 DB |
55 | [TCA_BPF_FD] = { .type = NLA_U32 }, |
56 | [TCA_BPF_NAME] = { .type = NLA_NUL_STRING, .len = CLS_BPF_NAME_LEN }, | |
7d1d65cb DB |
57 | [TCA_BPF_OPS_LEN] = { .type = NLA_U16 }, |
58 | [TCA_BPF_OPS] = { .type = NLA_BINARY, | |
59 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
60 | }; | |
61 | ||
7d1d65cb DB |
62 | static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp, |
63 | struct tcf_result *res) | |
64 | { | |
80dcbd12 | 65 | struct cls_bpf_head *head = rcu_dereference_bh(tp->root); |
7d1d65cb | 66 | struct cls_bpf_prog *prog; |
54720df1 | 67 | int ret = -1; |
7d1d65cb | 68 | |
a166151c AS |
69 | if (unlikely(!skb_mac_header_was_set(skb))) |
70 | return -1; | |
71 | ||
54720df1 DB |
72 | /* Needed here for accessing maps. */ |
73 | rcu_read_lock(); | |
1f947bf1 | 74 | list_for_each_entry_rcu(prog, &head->plist, link) { |
7ae457c1 | 75 | int filter_res = BPF_PROG_RUN(prog->filter, skb); |
7d1d65cb DB |
76 | |
77 | if (filter_res == 0) | |
78 | continue; | |
79 | ||
80 | *res = prog->res; | |
81 | if (filter_res != -1) | |
82 | res->classid = filter_res; | |
83 | ||
84 | ret = tcf_exts_exec(skb, &prog->exts, res); | |
85 | if (ret < 0) | |
86 | continue; | |
87 | ||
54720df1 | 88 | break; |
7d1d65cb | 89 | } |
54720df1 | 90 | rcu_read_unlock(); |
7d1d65cb | 91 | |
54720df1 | 92 | return ret; |
7d1d65cb DB |
93 | } |
94 | ||
e2e9b654 DB |
95 | static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog) |
96 | { | |
97 | return !prog->bpf_ops; | |
98 | } | |
99 | ||
7d1d65cb DB |
100 | static int cls_bpf_init(struct tcf_proto *tp) |
101 | { | |
102 | struct cls_bpf_head *head; | |
103 | ||
104 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
105 | if (head == NULL) | |
106 | return -ENOBUFS; | |
107 | ||
1f947bf1 JF |
108 | INIT_LIST_HEAD_RCU(&head->plist); |
109 | rcu_assign_pointer(tp->root, head); | |
7d1d65cb DB |
110 | |
111 | return 0; | |
112 | } | |
113 | ||
114 | static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog) | |
115 | { | |
18d0264f | 116 | tcf_exts_destroy(&prog->exts); |
7d1d65cb | 117 | |
e2e9b654 DB |
118 | if (cls_bpf_is_ebpf(prog)) |
119 | bpf_prog_put(prog->filter); | |
120 | else | |
121 | bpf_prog_destroy(prog->filter); | |
7d1d65cb | 122 | |
e2e9b654 | 123 | kfree(prog->bpf_name); |
7d1d65cb DB |
124 | kfree(prog->bpf_ops); |
125 | kfree(prog); | |
126 | } | |
127 | ||
1f947bf1 JF |
128 | static void __cls_bpf_delete_prog(struct rcu_head *rcu) |
129 | { | |
130 | struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu); | |
131 | ||
132 | cls_bpf_delete_prog(prog->tp, prog); | |
133 | } | |
134 | ||
7d1d65cb DB |
135 | static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) |
136 | { | |
472f5837 | 137 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg; |
7d1d65cb | 138 | |
472f5837 JP |
139 | list_del_rcu(&prog->link); |
140 | tcf_unbind_filter(tp, &prog->res); | |
141 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); | |
e2e9b654 | 142 | |
472f5837 | 143 | return 0; |
7d1d65cb DB |
144 | } |
145 | ||
1e052be6 | 146 | static bool cls_bpf_destroy(struct tcf_proto *tp, bool force) |
7d1d65cb | 147 | { |
1f947bf1 | 148 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
149 | struct cls_bpf_prog *prog, *tmp; |
150 | ||
1e052be6 CW |
151 | if (!force && !list_empty(&head->plist)) |
152 | return false; | |
153 | ||
7d1d65cb | 154 | list_for_each_entry_safe(prog, tmp, &head->plist, link) { |
1f947bf1 | 155 | list_del_rcu(&prog->link); |
18cdb37e | 156 | tcf_unbind_filter(tp, &prog->res); |
1f947bf1 | 157 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
7d1d65cb DB |
158 | } |
159 | ||
1f947bf1 JF |
160 | RCU_INIT_POINTER(tp->root, NULL); |
161 | kfree_rcu(head, rcu); | |
1e052be6 | 162 | return true; |
7d1d65cb DB |
163 | } |
164 | ||
165 | static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle) | |
166 | { | |
1f947bf1 | 167 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
168 | struct cls_bpf_prog *prog; |
169 | unsigned long ret = 0UL; | |
170 | ||
171 | if (head == NULL) | |
172 | return 0UL; | |
173 | ||
3fe6b49e | 174 | list_for_each_entry(prog, &head->plist, link) { |
7d1d65cb DB |
175 | if (prog->handle == handle) { |
176 | ret = (unsigned long) prog; | |
177 | break; | |
178 | } | |
179 | } | |
180 | ||
181 | return ret; | |
182 | } | |
183 | ||
e2e9b654 DB |
184 | static int cls_bpf_prog_from_ops(struct nlattr **tb, |
185 | struct cls_bpf_prog *prog, u32 classid) | |
7d1d65cb | 186 | { |
1f947bf1 | 187 | struct sock_filter *bpf_ops; |
e2e9b654 | 188 | struct sock_fprog_kern fprog_tmp; |
1f947bf1 | 189 | struct bpf_prog *fp; |
33e9fcc6 | 190 | u16 bpf_size, bpf_num_ops; |
7d1d65cb DB |
191 | int ret; |
192 | ||
33e9fcc6 | 193 | bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]); |
e2e9b654 DB |
194 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) |
195 | return -EINVAL; | |
7d1d65cb | 196 | |
33e9fcc6 | 197 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); |
e2e9b654 DB |
198 | if (bpf_size != nla_len(tb[TCA_BPF_OPS])) |
199 | return -EINVAL; | |
7913ecf6 | 200 | |
7d1d65cb | 201 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
e2e9b654 DB |
202 | if (bpf_ops == NULL) |
203 | return -ENOMEM; | |
7d1d65cb DB |
204 | |
205 | memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size); | |
206 | ||
e2e9b654 DB |
207 | fprog_tmp.len = bpf_num_ops; |
208 | fprog_tmp.filter = bpf_ops; | |
7d1d65cb | 209 | |
e2e9b654 DB |
210 | ret = bpf_prog_create(&fp, &fprog_tmp); |
211 | if (ret < 0) { | |
212 | kfree(bpf_ops); | |
213 | return ret; | |
214 | } | |
7d1d65cb | 215 | |
7d1d65cb | 216 | prog->bpf_ops = bpf_ops; |
e2e9b654 DB |
217 | prog->bpf_num_ops = bpf_num_ops; |
218 | prog->bpf_name = NULL; | |
219 | ||
7d1d65cb DB |
220 | prog->filter = fp; |
221 | prog->res.classid = classid; | |
7d1d65cb | 222 | |
e2e9b654 DB |
223 | return 0; |
224 | } | |
225 | ||
226 | static int cls_bpf_prog_from_efd(struct nlattr **tb, | |
227 | struct cls_bpf_prog *prog, u32 classid) | |
228 | { | |
229 | struct bpf_prog *fp; | |
230 | char *name = NULL; | |
231 | u32 bpf_fd; | |
232 | ||
233 | bpf_fd = nla_get_u32(tb[TCA_BPF_FD]); | |
234 | ||
235 | fp = bpf_prog_get(bpf_fd); | |
236 | if (IS_ERR(fp)) | |
237 | return PTR_ERR(fp); | |
238 | ||
239 | if (fp->type != BPF_PROG_TYPE_SCHED_CLS) { | |
240 | bpf_prog_put(fp); | |
241 | return -EINVAL; | |
242 | } | |
243 | ||
244 | if (tb[TCA_BPF_NAME]) { | |
245 | name = kmemdup(nla_data(tb[TCA_BPF_NAME]), | |
246 | nla_len(tb[TCA_BPF_NAME]), | |
247 | GFP_KERNEL); | |
248 | if (!name) { | |
249 | bpf_prog_put(fp); | |
250 | return -ENOMEM; | |
251 | } | |
252 | } | |
253 | ||
254 | prog->bpf_ops = NULL; | |
255 | prog->bpf_fd = bpf_fd; | |
256 | prog->bpf_name = name; | |
257 | ||
258 | prog->filter = fp; | |
259 | prog->res.classid = classid; | |
260 | ||
261 | return 0; | |
262 | } | |
263 | ||
264 | static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp, | |
265 | struct cls_bpf_prog *prog, | |
266 | unsigned long base, struct nlattr **tb, | |
267 | struct nlattr *est, bool ovr) | |
268 | { | |
269 | struct tcf_exts exts; | |
270 | bool is_bpf, is_ebpf; | |
271 | u32 classid; | |
272 | int ret; | |
273 | ||
274 | is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS]; | |
275 | is_ebpf = tb[TCA_BPF_FD]; | |
276 | ||
277 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) || | |
278 | !tb[TCA_BPF_CLASSID]) | |
279 | return -EINVAL; | |
280 | ||
281 | tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE); | |
282 | ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr); | |
283 | if (ret < 0) | |
284 | return ret; | |
285 | ||
286 | classid = nla_get_u32(tb[TCA_BPF_CLASSID]); | |
287 | ||
288 | ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) : | |
289 | cls_bpf_prog_from_efd(tb, prog, classid); | |
290 | if (ret < 0) { | |
291 | tcf_exts_destroy(&exts); | |
292 | return ret; | |
293 | } | |
294 | ||
7d1d65cb DB |
295 | tcf_bind_filter(tp, &prog->res, base); |
296 | tcf_exts_change(tp, &prog->exts, &exts); | |
297 | ||
7d1d65cb | 298 | return 0; |
7d1d65cb DB |
299 | } |
300 | ||
301 | static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, | |
302 | struct cls_bpf_head *head) | |
303 | { | |
304 | unsigned int i = 0x80000000; | |
3f2ab135 | 305 | u32 handle; |
7d1d65cb DB |
306 | |
307 | do { | |
308 | if (++head->hgen == 0x7FFFFFFF) | |
309 | head->hgen = 1; | |
310 | } while (--i > 0 && cls_bpf_get(tp, head->hgen)); | |
3f2ab135 DB |
311 | |
312 | if (unlikely(i == 0)) { | |
7d1d65cb | 313 | pr_err("Insufficient number of handles\n"); |
3f2ab135 DB |
314 | handle = 0; |
315 | } else { | |
316 | handle = head->hgen; | |
317 | } | |
7d1d65cb | 318 | |
3f2ab135 | 319 | return handle; |
7d1d65cb DB |
320 | } |
321 | ||
322 | static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, | |
323 | struct tcf_proto *tp, unsigned long base, | |
324 | u32 handle, struct nlattr **tca, | |
2f7ef2f8 | 325 | unsigned long *arg, bool ovr) |
7d1d65cb | 326 | { |
1f947bf1 JF |
327 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
328 | struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg; | |
7d1d65cb | 329 | struct nlattr *tb[TCA_BPF_MAX + 1]; |
1f947bf1 | 330 | struct cls_bpf_prog *prog; |
7d1d65cb DB |
331 | int ret; |
332 | ||
333 | if (tca[TCA_OPTIONS] == NULL) | |
334 | return -EINVAL; | |
335 | ||
336 | ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy); | |
337 | if (ret < 0) | |
338 | return ret; | |
339 | ||
7d1d65cb | 340 | prog = kzalloc(sizeof(*prog), GFP_KERNEL); |
1f947bf1 | 341 | if (!prog) |
7d1d65cb DB |
342 | return -ENOBUFS; |
343 | ||
5da57f42 | 344 | tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
1f947bf1 JF |
345 | |
346 | if (oldprog) { | |
347 | if (handle && oldprog->handle != handle) { | |
348 | ret = -EINVAL; | |
349 | goto errout; | |
350 | } | |
351 | } | |
352 | ||
7d1d65cb DB |
353 | if (handle == 0) |
354 | prog->handle = cls_bpf_grab_new_handle(tp, head); | |
355 | else | |
356 | prog->handle = handle; | |
357 | if (prog->handle == 0) { | |
358 | ret = -EINVAL; | |
359 | goto errout; | |
360 | } | |
361 | ||
2f7ef2f8 | 362 | ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr); |
7d1d65cb DB |
363 | if (ret < 0) |
364 | goto errout; | |
365 | ||
1f947bf1 JF |
366 | if (oldprog) { |
367 | list_replace_rcu(&prog->link, &oldprog->link); | |
18cdb37e | 368 | tcf_unbind_filter(tp, &oldprog->res); |
1f947bf1 JF |
369 | call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); |
370 | } else { | |
371 | list_add_rcu(&prog->link, &head->plist); | |
372 | } | |
7d1d65cb DB |
373 | |
374 | *arg = (unsigned long) prog; | |
7d1d65cb DB |
375 | return 0; |
376 | errout: | |
1f947bf1 | 377 | kfree(prog); |
7d1d65cb DB |
378 | |
379 | return ret; | |
380 | } | |
381 | ||
e2e9b654 DB |
382 | static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog, |
383 | struct sk_buff *skb) | |
384 | { | |
385 | struct nlattr *nla; | |
386 | ||
387 | if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops)) | |
388 | return -EMSGSIZE; | |
389 | ||
390 | nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops * | |
391 | sizeof(struct sock_filter)); | |
392 | if (nla == NULL) | |
393 | return -EMSGSIZE; | |
394 | ||
395 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); | |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
400 | static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog, | |
401 | struct sk_buff *skb) | |
402 | { | |
403 | if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd)) | |
404 | return -EMSGSIZE; | |
405 | ||
406 | if (prog->bpf_name && | |
407 | nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name)) | |
408 | return -EMSGSIZE; | |
409 | ||
410 | return 0; | |
411 | } | |
412 | ||
832d1d5b | 413 | static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, |
7d1d65cb DB |
414 | struct sk_buff *skb, struct tcmsg *tm) |
415 | { | |
416 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh; | |
e2e9b654 DB |
417 | struct nlattr *nest; |
418 | int ret; | |
7d1d65cb DB |
419 | |
420 | if (prog == NULL) | |
421 | return skb->len; | |
422 | ||
423 | tm->tcm_handle = prog->handle; | |
424 | ||
425 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
426 | if (nest == NULL) | |
427 | goto nla_put_failure; | |
428 | ||
429 | if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid)) | |
430 | goto nla_put_failure; | |
7d1d65cb | 431 | |
e2e9b654 DB |
432 | if (cls_bpf_is_ebpf(prog)) |
433 | ret = cls_bpf_dump_ebpf_info(prog, skb); | |
434 | else | |
435 | ret = cls_bpf_dump_bpf_info(prog, skb); | |
436 | if (ret) | |
7d1d65cb DB |
437 | goto nla_put_failure; |
438 | ||
5da57f42 | 439 | if (tcf_exts_dump(skb, &prog->exts) < 0) |
7d1d65cb DB |
440 | goto nla_put_failure; |
441 | ||
442 | nla_nest_end(skb, nest); | |
443 | ||
5da57f42 | 444 | if (tcf_exts_dump_stats(skb, &prog->exts) < 0) |
7d1d65cb DB |
445 | goto nla_put_failure; |
446 | ||
447 | return skb->len; | |
448 | ||
449 | nla_put_failure: | |
450 | nla_nest_cancel(skb, nest); | |
451 | return -1; | |
452 | } | |
453 | ||
454 | static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
455 | { | |
1f947bf1 | 456 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
457 | struct cls_bpf_prog *prog; |
458 | ||
3fe6b49e | 459 | list_for_each_entry(prog, &head->plist, link) { |
7d1d65cb DB |
460 | if (arg->count < arg->skip) |
461 | goto skip; | |
462 | if (arg->fn(tp, (unsigned long) prog, arg) < 0) { | |
463 | arg->stop = 1; | |
464 | break; | |
465 | } | |
466 | skip: | |
467 | arg->count++; | |
468 | } | |
469 | } | |
470 | ||
471 | static struct tcf_proto_ops cls_bpf_ops __read_mostly = { | |
472 | .kind = "bpf", | |
473 | .owner = THIS_MODULE, | |
474 | .classify = cls_bpf_classify, | |
475 | .init = cls_bpf_init, | |
476 | .destroy = cls_bpf_destroy, | |
477 | .get = cls_bpf_get, | |
7d1d65cb DB |
478 | .change = cls_bpf_change, |
479 | .delete = cls_bpf_delete, | |
480 | .walk = cls_bpf_walk, | |
481 | .dump = cls_bpf_dump, | |
482 | }; | |
483 | ||
484 | static int __init cls_bpf_init_mod(void) | |
485 | { | |
486 | return register_tcf_proto_ops(&cls_bpf_ops); | |
487 | } | |
488 | ||
489 | static void __exit cls_bpf_exit_mod(void) | |
490 | { | |
491 | unregister_tcf_proto_ops(&cls_bpf_ops); | |
492 | } | |
493 | ||
494 | module_init(cls_bpf_init_mod); | |
495 | module_exit(cls_bpf_exit_mod); |