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> | |
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; |
3431205e AS |
67 | #ifdef CONFIG_NET_CLS_ACT |
68 | bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS; | |
69 | #else | |
70 | bool at_ingress = false; | |
71 | #endif | |
54720df1 | 72 | int ret = -1; |
7d1d65cb | 73 | |
a166151c AS |
74 | if (unlikely(!skb_mac_header_was_set(skb))) |
75 | return -1; | |
76 | ||
54720df1 DB |
77 | /* Needed here for accessing maps. */ |
78 | rcu_read_lock(); | |
1f947bf1 | 79 | list_for_each_entry_rcu(prog, &head->plist, link) { |
3431205e AS |
80 | int filter_res; |
81 | ||
82 | if (at_ingress) { | |
83 | /* It is safe to push/pull even if skb_shared() */ | |
84 | __skb_push(skb, skb->mac_len); | |
85 | filter_res = BPF_PROG_RUN(prog->filter, skb); | |
86 | __skb_pull(skb, skb->mac_len); | |
87 | } else { | |
88 | filter_res = BPF_PROG_RUN(prog->filter, skb); | |
89 | } | |
7d1d65cb DB |
90 | |
91 | if (filter_res == 0) | |
92 | continue; | |
93 | ||
94 | *res = prog->res; | |
95 | if (filter_res != -1) | |
96 | res->classid = filter_res; | |
97 | ||
98 | ret = tcf_exts_exec(skb, &prog->exts, res); | |
99 | if (ret < 0) | |
100 | continue; | |
101 | ||
54720df1 | 102 | break; |
7d1d65cb | 103 | } |
54720df1 | 104 | rcu_read_unlock(); |
7d1d65cb | 105 | |
54720df1 | 106 | return ret; |
7d1d65cb DB |
107 | } |
108 | ||
e2e9b654 DB |
109 | static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog) |
110 | { | |
111 | return !prog->bpf_ops; | |
112 | } | |
113 | ||
7d1d65cb DB |
114 | static int cls_bpf_init(struct tcf_proto *tp) |
115 | { | |
116 | struct cls_bpf_head *head; | |
117 | ||
118 | head = kzalloc(sizeof(*head), GFP_KERNEL); | |
119 | if (head == NULL) | |
120 | return -ENOBUFS; | |
121 | ||
1f947bf1 JF |
122 | INIT_LIST_HEAD_RCU(&head->plist); |
123 | rcu_assign_pointer(tp->root, head); | |
7d1d65cb DB |
124 | |
125 | return 0; | |
126 | } | |
127 | ||
128 | static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog) | |
129 | { | |
18d0264f | 130 | tcf_exts_destroy(&prog->exts); |
7d1d65cb | 131 | |
e2e9b654 DB |
132 | if (cls_bpf_is_ebpf(prog)) |
133 | bpf_prog_put(prog->filter); | |
134 | else | |
135 | bpf_prog_destroy(prog->filter); | |
7d1d65cb | 136 | |
e2e9b654 | 137 | kfree(prog->bpf_name); |
7d1d65cb DB |
138 | kfree(prog->bpf_ops); |
139 | kfree(prog); | |
140 | } | |
141 | ||
1f947bf1 JF |
142 | static void __cls_bpf_delete_prog(struct rcu_head *rcu) |
143 | { | |
144 | struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu); | |
145 | ||
146 | cls_bpf_delete_prog(prog->tp, prog); | |
147 | } | |
148 | ||
7d1d65cb DB |
149 | static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg) |
150 | { | |
472f5837 | 151 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg; |
7d1d65cb | 152 | |
472f5837 JP |
153 | list_del_rcu(&prog->link); |
154 | tcf_unbind_filter(tp, &prog->res); | |
155 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); | |
e2e9b654 | 156 | |
472f5837 | 157 | return 0; |
7d1d65cb DB |
158 | } |
159 | ||
1e052be6 | 160 | static bool cls_bpf_destroy(struct tcf_proto *tp, bool force) |
7d1d65cb | 161 | { |
1f947bf1 | 162 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
163 | struct cls_bpf_prog *prog, *tmp; |
164 | ||
1e052be6 CW |
165 | if (!force && !list_empty(&head->plist)) |
166 | return false; | |
167 | ||
7d1d65cb | 168 | list_for_each_entry_safe(prog, tmp, &head->plist, link) { |
1f947bf1 | 169 | list_del_rcu(&prog->link); |
18cdb37e | 170 | tcf_unbind_filter(tp, &prog->res); |
1f947bf1 | 171 | call_rcu(&prog->rcu, __cls_bpf_delete_prog); |
7d1d65cb DB |
172 | } |
173 | ||
1f947bf1 JF |
174 | RCU_INIT_POINTER(tp->root, NULL); |
175 | kfree_rcu(head, rcu); | |
1e052be6 | 176 | return true; |
7d1d65cb DB |
177 | } |
178 | ||
179 | static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle) | |
180 | { | |
1f947bf1 | 181 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
182 | struct cls_bpf_prog *prog; |
183 | unsigned long ret = 0UL; | |
184 | ||
185 | if (head == NULL) | |
186 | return 0UL; | |
187 | ||
3fe6b49e | 188 | list_for_each_entry(prog, &head->plist, link) { |
7d1d65cb DB |
189 | if (prog->handle == handle) { |
190 | ret = (unsigned long) prog; | |
191 | break; | |
192 | } | |
193 | } | |
194 | ||
195 | return ret; | |
196 | } | |
197 | ||
e2e9b654 DB |
198 | static int cls_bpf_prog_from_ops(struct nlattr **tb, |
199 | struct cls_bpf_prog *prog, u32 classid) | |
7d1d65cb | 200 | { |
1f947bf1 | 201 | struct sock_filter *bpf_ops; |
e2e9b654 | 202 | struct sock_fprog_kern fprog_tmp; |
1f947bf1 | 203 | struct bpf_prog *fp; |
33e9fcc6 | 204 | u16 bpf_size, bpf_num_ops; |
7d1d65cb DB |
205 | int ret; |
206 | ||
33e9fcc6 | 207 | bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]); |
e2e9b654 DB |
208 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) |
209 | return -EINVAL; | |
7d1d65cb | 210 | |
33e9fcc6 | 211 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); |
e2e9b654 DB |
212 | if (bpf_size != nla_len(tb[TCA_BPF_OPS])) |
213 | return -EINVAL; | |
7913ecf6 | 214 | |
7d1d65cb | 215 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
e2e9b654 DB |
216 | if (bpf_ops == NULL) |
217 | return -ENOMEM; | |
7d1d65cb DB |
218 | |
219 | memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size); | |
220 | ||
e2e9b654 DB |
221 | fprog_tmp.len = bpf_num_ops; |
222 | fprog_tmp.filter = bpf_ops; | |
7d1d65cb | 223 | |
e2e9b654 DB |
224 | ret = bpf_prog_create(&fp, &fprog_tmp); |
225 | if (ret < 0) { | |
226 | kfree(bpf_ops); | |
227 | return ret; | |
228 | } | |
7d1d65cb | 229 | |
7d1d65cb | 230 | prog->bpf_ops = bpf_ops; |
e2e9b654 DB |
231 | prog->bpf_num_ops = bpf_num_ops; |
232 | prog->bpf_name = NULL; | |
233 | ||
7d1d65cb DB |
234 | prog->filter = fp; |
235 | prog->res.classid = classid; | |
7d1d65cb | 236 | |
e2e9b654 DB |
237 | return 0; |
238 | } | |
239 | ||
240 | static int cls_bpf_prog_from_efd(struct nlattr **tb, | |
241 | struct cls_bpf_prog *prog, u32 classid) | |
242 | { | |
243 | struct bpf_prog *fp; | |
244 | char *name = NULL; | |
245 | u32 bpf_fd; | |
246 | ||
247 | bpf_fd = nla_get_u32(tb[TCA_BPF_FD]); | |
248 | ||
249 | fp = bpf_prog_get(bpf_fd); | |
250 | if (IS_ERR(fp)) | |
251 | return PTR_ERR(fp); | |
252 | ||
253 | if (fp->type != BPF_PROG_TYPE_SCHED_CLS) { | |
254 | bpf_prog_put(fp); | |
255 | return -EINVAL; | |
256 | } | |
257 | ||
258 | if (tb[TCA_BPF_NAME]) { | |
259 | name = kmemdup(nla_data(tb[TCA_BPF_NAME]), | |
260 | nla_len(tb[TCA_BPF_NAME]), | |
261 | GFP_KERNEL); | |
262 | if (!name) { | |
263 | bpf_prog_put(fp); | |
264 | return -ENOMEM; | |
265 | } | |
266 | } | |
267 | ||
268 | prog->bpf_ops = NULL; | |
269 | prog->bpf_fd = bpf_fd; | |
270 | prog->bpf_name = name; | |
271 | ||
272 | prog->filter = fp; | |
273 | prog->res.classid = classid; | |
274 | ||
275 | return 0; | |
276 | } | |
277 | ||
278 | static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp, | |
279 | struct cls_bpf_prog *prog, | |
280 | unsigned long base, struct nlattr **tb, | |
281 | struct nlattr *est, bool ovr) | |
282 | { | |
283 | struct tcf_exts exts; | |
284 | bool is_bpf, is_ebpf; | |
285 | u32 classid; | |
286 | int ret; | |
287 | ||
288 | is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS]; | |
289 | is_ebpf = tb[TCA_BPF_FD]; | |
290 | ||
291 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) || | |
292 | !tb[TCA_BPF_CLASSID]) | |
293 | return -EINVAL; | |
294 | ||
295 | tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE); | |
296 | ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr); | |
297 | if (ret < 0) | |
298 | return ret; | |
299 | ||
300 | classid = nla_get_u32(tb[TCA_BPF_CLASSID]); | |
301 | ||
302 | ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog, classid) : | |
303 | cls_bpf_prog_from_efd(tb, prog, classid); | |
304 | if (ret < 0) { | |
305 | tcf_exts_destroy(&exts); | |
306 | return ret; | |
307 | } | |
308 | ||
7d1d65cb DB |
309 | tcf_bind_filter(tp, &prog->res, base); |
310 | tcf_exts_change(tp, &prog->exts, &exts); | |
311 | ||
7d1d65cb | 312 | return 0; |
7d1d65cb DB |
313 | } |
314 | ||
315 | static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, | |
316 | struct cls_bpf_head *head) | |
317 | { | |
318 | unsigned int i = 0x80000000; | |
3f2ab135 | 319 | u32 handle; |
7d1d65cb DB |
320 | |
321 | do { | |
322 | if (++head->hgen == 0x7FFFFFFF) | |
323 | head->hgen = 1; | |
324 | } while (--i > 0 && cls_bpf_get(tp, head->hgen)); | |
3f2ab135 DB |
325 | |
326 | if (unlikely(i == 0)) { | |
7d1d65cb | 327 | pr_err("Insufficient number of handles\n"); |
3f2ab135 DB |
328 | handle = 0; |
329 | } else { | |
330 | handle = head->hgen; | |
331 | } | |
7d1d65cb | 332 | |
3f2ab135 | 333 | return handle; |
7d1d65cb DB |
334 | } |
335 | ||
336 | static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, | |
337 | struct tcf_proto *tp, unsigned long base, | |
338 | u32 handle, struct nlattr **tca, | |
2f7ef2f8 | 339 | unsigned long *arg, bool ovr) |
7d1d65cb | 340 | { |
1f947bf1 JF |
341 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
342 | struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg; | |
7d1d65cb | 343 | struct nlattr *tb[TCA_BPF_MAX + 1]; |
1f947bf1 | 344 | struct cls_bpf_prog *prog; |
7d1d65cb DB |
345 | int ret; |
346 | ||
347 | if (tca[TCA_OPTIONS] == NULL) | |
348 | return -EINVAL; | |
349 | ||
350 | ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy); | |
351 | if (ret < 0) | |
352 | return ret; | |
353 | ||
7d1d65cb | 354 | prog = kzalloc(sizeof(*prog), GFP_KERNEL); |
1f947bf1 | 355 | if (!prog) |
7d1d65cb DB |
356 | return -ENOBUFS; |
357 | ||
5da57f42 | 358 | tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE); |
1f947bf1 JF |
359 | |
360 | if (oldprog) { | |
361 | if (handle && oldprog->handle != handle) { | |
362 | ret = -EINVAL; | |
363 | goto errout; | |
364 | } | |
365 | } | |
366 | ||
7d1d65cb DB |
367 | if (handle == 0) |
368 | prog->handle = cls_bpf_grab_new_handle(tp, head); | |
369 | else | |
370 | prog->handle = handle; | |
371 | if (prog->handle == 0) { | |
372 | ret = -EINVAL; | |
373 | goto errout; | |
374 | } | |
375 | ||
2f7ef2f8 | 376 | ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr); |
7d1d65cb DB |
377 | if (ret < 0) |
378 | goto errout; | |
379 | ||
1f947bf1 JF |
380 | if (oldprog) { |
381 | list_replace_rcu(&prog->link, &oldprog->link); | |
18cdb37e | 382 | tcf_unbind_filter(tp, &oldprog->res); |
1f947bf1 JF |
383 | call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); |
384 | } else { | |
385 | list_add_rcu(&prog->link, &head->plist); | |
386 | } | |
7d1d65cb DB |
387 | |
388 | *arg = (unsigned long) prog; | |
7d1d65cb DB |
389 | return 0; |
390 | errout: | |
1f947bf1 | 391 | kfree(prog); |
7d1d65cb DB |
392 | |
393 | return ret; | |
394 | } | |
395 | ||
e2e9b654 DB |
396 | static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog, |
397 | struct sk_buff *skb) | |
398 | { | |
399 | struct nlattr *nla; | |
400 | ||
401 | if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops)) | |
402 | return -EMSGSIZE; | |
403 | ||
404 | nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops * | |
405 | sizeof(struct sock_filter)); | |
406 | if (nla == NULL) | |
407 | return -EMSGSIZE; | |
408 | ||
409 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); | |
410 | ||
411 | return 0; | |
412 | } | |
413 | ||
414 | static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog, | |
415 | struct sk_buff *skb) | |
416 | { | |
417 | if (nla_put_u32(skb, TCA_BPF_FD, prog->bpf_fd)) | |
418 | return -EMSGSIZE; | |
419 | ||
420 | if (prog->bpf_name && | |
421 | nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name)) | |
422 | return -EMSGSIZE; | |
423 | ||
424 | return 0; | |
425 | } | |
426 | ||
832d1d5b | 427 | static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, |
7d1d65cb DB |
428 | struct sk_buff *skb, struct tcmsg *tm) |
429 | { | |
430 | struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh; | |
e2e9b654 DB |
431 | struct nlattr *nest; |
432 | int ret; | |
7d1d65cb DB |
433 | |
434 | if (prog == NULL) | |
435 | return skb->len; | |
436 | ||
437 | tm->tcm_handle = prog->handle; | |
438 | ||
439 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
440 | if (nest == NULL) | |
441 | goto nla_put_failure; | |
442 | ||
443 | if (nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid)) | |
444 | goto nla_put_failure; | |
7d1d65cb | 445 | |
e2e9b654 DB |
446 | if (cls_bpf_is_ebpf(prog)) |
447 | ret = cls_bpf_dump_ebpf_info(prog, skb); | |
448 | else | |
449 | ret = cls_bpf_dump_bpf_info(prog, skb); | |
450 | if (ret) | |
7d1d65cb DB |
451 | goto nla_put_failure; |
452 | ||
5da57f42 | 453 | if (tcf_exts_dump(skb, &prog->exts) < 0) |
7d1d65cb DB |
454 | goto nla_put_failure; |
455 | ||
456 | nla_nest_end(skb, nest); | |
457 | ||
5da57f42 | 458 | if (tcf_exts_dump_stats(skb, &prog->exts) < 0) |
7d1d65cb DB |
459 | goto nla_put_failure; |
460 | ||
461 | return skb->len; | |
462 | ||
463 | nla_put_failure: | |
464 | nla_nest_cancel(skb, nest); | |
465 | return -1; | |
466 | } | |
467 | ||
468 | static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg) | |
469 | { | |
1f947bf1 | 470 | struct cls_bpf_head *head = rtnl_dereference(tp->root); |
7d1d65cb DB |
471 | struct cls_bpf_prog *prog; |
472 | ||
3fe6b49e | 473 | list_for_each_entry(prog, &head->plist, link) { |
7d1d65cb DB |
474 | if (arg->count < arg->skip) |
475 | goto skip; | |
476 | if (arg->fn(tp, (unsigned long) prog, arg) < 0) { | |
477 | arg->stop = 1; | |
478 | break; | |
479 | } | |
480 | skip: | |
481 | arg->count++; | |
482 | } | |
483 | } | |
484 | ||
485 | static struct tcf_proto_ops cls_bpf_ops __read_mostly = { | |
486 | .kind = "bpf", | |
487 | .owner = THIS_MODULE, | |
488 | .classify = cls_bpf_classify, | |
489 | .init = cls_bpf_init, | |
490 | .destroy = cls_bpf_destroy, | |
491 | .get = cls_bpf_get, | |
7d1d65cb DB |
492 | .change = cls_bpf_change, |
493 | .delete = cls_bpf_delete, | |
494 | .walk = cls_bpf_walk, | |
495 | .dump = cls_bpf_dump, | |
496 | }; | |
497 | ||
498 | static int __init cls_bpf_init_mod(void) | |
499 | { | |
500 | return register_tcf_proto_ops(&cls_bpf_ops); | |
501 | } | |
502 | ||
503 | static void __exit cls_bpf_exit_mod(void) | |
504 | { | |
505 | unregister_tcf_proto_ops(&cls_bpf_ops); | |
506 | } | |
507 | ||
508 | module_init(cls_bpf_init_mod); | |
509 | module_exit(cls_bpf_exit_mod); |