]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - net/sched/cls_bpf.c
Merge tag 'mfd-for-linus-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd
[mirror_ubuntu-artful-kernel.git] / net / sched / cls_bpf.c
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 <linux/bpf.h>
20
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
29 #define CLS_BPF_NAME_LEN 256
30 #define CLS_BPF_SUPPORTED_GEN_FLAGS \
31 (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
32
33 struct cls_bpf_head {
34 struct list_head plist;
35 u32 hgen;
36 struct rcu_head rcu;
37 };
38
39 struct cls_bpf_prog {
40 struct bpf_prog *filter;
41 struct list_head link;
42 struct tcf_result res;
43 bool exts_integrated;
44 bool offloaded;
45 u32 gen_flags;
46 struct tcf_exts exts;
47 u32 handle;
48 u16 bpf_num_ops;
49 struct sock_filter *bpf_ops;
50 const char *bpf_name;
51 struct tcf_proto *tp;
52 struct rcu_head rcu;
53 };
54
55 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
56 [TCA_BPF_CLASSID] = { .type = NLA_U32 },
57 [TCA_BPF_FLAGS] = { .type = NLA_U32 },
58 [TCA_BPF_FLAGS_GEN] = { .type = NLA_U32 },
59 [TCA_BPF_FD] = { .type = NLA_U32 },
60 [TCA_BPF_NAME] = { .type = NLA_NUL_STRING,
61 .len = CLS_BPF_NAME_LEN },
62 [TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
63 [TCA_BPF_OPS] = { .type = NLA_BINARY,
64 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
65 };
66
67 static int cls_bpf_exec_opcode(int code)
68 {
69 switch (code) {
70 case TC_ACT_OK:
71 case TC_ACT_SHOT:
72 case TC_ACT_STOLEN:
73 case TC_ACT_REDIRECT:
74 case TC_ACT_UNSPEC:
75 return code;
76 default:
77 return TC_ACT_UNSPEC;
78 }
79 }
80
81 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
82 struct tcf_result *res)
83 {
84 struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
85 bool at_ingress = skb_at_tc_ingress(skb);
86 struct cls_bpf_prog *prog;
87 int ret = -1;
88
89 /* Needed here for accessing maps. */
90 rcu_read_lock();
91 list_for_each_entry_rcu(prog, &head->plist, link) {
92 int filter_res;
93
94 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
95
96 if (tc_skip_sw(prog->gen_flags)) {
97 filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
98 } else if (at_ingress) {
99 /* It is safe to push/pull even if skb_shared() */
100 __skb_push(skb, skb->mac_len);
101 bpf_compute_data_end(skb);
102 filter_res = BPF_PROG_RUN(prog->filter, skb);
103 __skb_pull(skb, skb->mac_len);
104 } else {
105 bpf_compute_data_end(skb);
106 filter_res = BPF_PROG_RUN(prog->filter, skb);
107 }
108
109 if (prog->exts_integrated) {
110 res->class = 0;
111 res->classid = TC_H_MAJ(prog->res.classid) |
112 qdisc_skb_cb(skb)->tc_classid;
113
114 ret = cls_bpf_exec_opcode(filter_res);
115 if (ret == TC_ACT_UNSPEC)
116 continue;
117 break;
118 }
119
120 if (filter_res == 0)
121 continue;
122 if (filter_res != -1) {
123 res->class = 0;
124 res->classid = filter_res;
125 } else {
126 *res = prog->res;
127 }
128
129 ret = tcf_exts_exec(skb, &prog->exts, res);
130 if (ret < 0)
131 continue;
132
133 break;
134 }
135 rcu_read_unlock();
136
137 return ret;
138 }
139
140 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
141 {
142 return !prog->bpf_ops;
143 }
144
145 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
146 enum tc_clsbpf_command cmd)
147 {
148 struct net_device *dev = tp->q->dev_queue->dev;
149 struct tc_cls_bpf_offload bpf_offload = {};
150 struct tc_to_netdev offload;
151 int err;
152
153 offload.type = TC_SETUP_CLSBPF;
154 offload.cls_bpf = &bpf_offload;
155
156 bpf_offload.command = cmd;
157 bpf_offload.exts = &prog->exts;
158 bpf_offload.prog = prog->filter;
159 bpf_offload.name = prog->bpf_name;
160 bpf_offload.exts_integrated = prog->exts_integrated;
161 bpf_offload.gen_flags = prog->gen_flags;
162
163 err = dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
164 tp->protocol, &offload);
165
166 if (!err && (cmd == TC_CLSBPF_ADD || cmd == TC_CLSBPF_REPLACE))
167 prog->gen_flags |= TCA_CLS_FLAGS_IN_HW;
168
169 return err;
170 }
171
172 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
173 struct cls_bpf_prog *oldprog)
174 {
175 struct net_device *dev = tp->q->dev_queue->dev;
176 struct cls_bpf_prog *obj = prog;
177 enum tc_clsbpf_command cmd;
178 bool skip_sw;
179 int ret;
180
181 skip_sw = tc_skip_sw(prog->gen_flags) ||
182 (oldprog && tc_skip_sw(oldprog->gen_flags));
183
184 if (oldprog && oldprog->offloaded) {
185 if (tc_should_offload(dev, tp, prog->gen_flags)) {
186 cmd = TC_CLSBPF_REPLACE;
187 } else if (!tc_skip_sw(prog->gen_flags)) {
188 obj = oldprog;
189 cmd = TC_CLSBPF_DESTROY;
190 } else {
191 return -EINVAL;
192 }
193 } else {
194 if (!tc_should_offload(dev, tp, prog->gen_flags))
195 return skip_sw ? -EINVAL : 0;
196 cmd = TC_CLSBPF_ADD;
197 }
198
199 ret = cls_bpf_offload_cmd(tp, obj, cmd);
200 if (ret)
201 return skip_sw ? ret : 0;
202
203 obj->offloaded = true;
204 if (oldprog)
205 oldprog->offloaded = false;
206
207 return 0;
208 }
209
210 static void cls_bpf_stop_offload(struct tcf_proto *tp,
211 struct cls_bpf_prog *prog)
212 {
213 int err;
214
215 if (!prog->offloaded)
216 return;
217
218 err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
219 if (err) {
220 pr_err("Stopping hardware offload failed: %d\n", err);
221 return;
222 }
223
224 prog->offloaded = false;
225 }
226
227 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
228 struct cls_bpf_prog *prog)
229 {
230 if (!prog->offloaded)
231 return;
232
233 cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS);
234 }
235
236 static int cls_bpf_init(struct tcf_proto *tp)
237 {
238 struct cls_bpf_head *head;
239
240 head = kzalloc(sizeof(*head), GFP_KERNEL);
241 if (head == NULL)
242 return -ENOBUFS;
243
244 INIT_LIST_HEAD_RCU(&head->plist);
245 rcu_assign_pointer(tp->root, head);
246
247 return 0;
248 }
249
250 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
251 {
252 tcf_exts_destroy(&prog->exts);
253
254 if (cls_bpf_is_ebpf(prog))
255 bpf_prog_put(prog->filter);
256 else
257 bpf_prog_destroy(prog->filter);
258
259 kfree(prog->bpf_name);
260 kfree(prog->bpf_ops);
261 kfree(prog);
262 }
263
264 static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
265 {
266 __cls_bpf_delete_prog(container_of(rcu, struct cls_bpf_prog, rcu));
267 }
268
269 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
270 {
271 cls_bpf_stop_offload(tp, prog);
272 list_del_rcu(&prog->link);
273 tcf_unbind_filter(tp, &prog->res);
274 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
275 }
276
277 static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
278 {
279 __cls_bpf_delete(tp, (struct cls_bpf_prog *) arg);
280 return 0;
281 }
282
283 static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
284 {
285 struct cls_bpf_head *head = rtnl_dereference(tp->root);
286 struct cls_bpf_prog *prog, *tmp;
287
288 if (!force && !list_empty(&head->plist))
289 return false;
290
291 list_for_each_entry_safe(prog, tmp, &head->plist, link)
292 __cls_bpf_delete(tp, prog);
293
294 kfree_rcu(head, rcu);
295 return true;
296 }
297
298 static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
299 {
300 struct cls_bpf_head *head = rtnl_dereference(tp->root);
301 struct cls_bpf_prog *prog;
302 unsigned long ret = 0UL;
303
304 list_for_each_entry(prog, &head->plist, link) {
305 if (prog->handle == handle) {
306 ret = (unsigned long) prog;
307 break;
308 }
309 }
310
311 return ret;
312 }
313
314 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
315 {
316 struct sock_filter *bpf_ops;
317 struct sock_fprog_kern fprog_tmp;
318 struct bpf_prog *fp;
319 u16 bpf_size, bpf_num_ops;
320 int ret;
321
322 bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
323 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
324 return -EINVAL;
325
326 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
327 if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
328 return -EINVAL;
329
330 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
331 if (bpf_ops == NULL)
332 return -ENOMEM;
333
334 memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
335
336 fprog_tmp.len = bpf_num_ops;
337 fprog_tmp.filter = bpf_ops;
338
339 ret = bpf_prog_create(&fp, &fprog_tmp);
340 if (ret < 0) {
341 kfree(bpf_ops);
342 return ret;
343 }
344
345 prog->bpf_ops = bpf_ops;
346 prog->bpf_num_ops = bpf_num_ops;
347 prog->bpf_name = NULL;
348 prog->filter = fp;
349
350 return 0;
351 }
352
353 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
354 const struct tcf_proto *tp)
355 {
356 struct bpf_prog *fp;
357 char *name = NULL;
358 u32 bpf_fd;
359
360 bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
361
362 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
363 if (IS_ERR(fp))
364 return PTR_ERR(fp);
365
366 if (tb[TCA_BPF_NAME]) {
367 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
368 if (!name) {
369 bpf_prog_put(fp);
370 return -ENOMEM;
371 }
372 }
373
374 prog->bpf_ops = NULL;
375 prog->bpf_name = name;
376 prog->filter = fp;
377
378 if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
379 netif_keep_dst(qdisc_dev(tp->q));
380
381 return 0;
382 }
383
384 static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
385 struct cls_bpf_prog *prog,
386 unsigned long base, struct nlattr **tb,
387 struct nlattr *est, bool ovr)
388 {
389 bool is_bpf, is_ebpf, have_exts = false;
390 struct tcf_exts exts;
391 u32 gen_flags = 0;
392 int ret;
393
394 is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
395 is_ebpf = tb[TCA_BPF_FD];
396 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
397 return -EINVAL;
398
399 ret = tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
400 if (ret < 0)
401 return ret;
402 ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
403 if (ret < 0)
404 goto errout;
405
406 if (tb[TCA_BPF_FLAGS]) {
407 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
408
409 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
410 ret = -EINVAL;
411 goto errout;
412 }
413
414 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
415 }
416 if (tb[TCA_BPF_FLAGS_GEN]) {
417 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
418 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
419 !tc_flags_valid(gen_flags)) {
420 ret = -EINVAL;
421 goto errout;
422 }
423 }
424
425 prog->exts_integrated = have_exts;
426 prog->gen_flags = gen_flags;
427
428 ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
429 cls_bpf_prog_from_efd(tb, prog, tp);
430 if (ret < 0)
431 goto errout;
432
433 if (tb[TCA_BPF_CLASSID]) {
434 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
435 tcf_bind_filter(tp, &prog->res, base);
436 }
437
438 tcf_exts_change(tp, &prog->exts, &exts);
439 return 0;
440
441 errout:
442 tcf_exts_destroy(&exts);
443 return ret;
444 }
445
446 static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
447 struct cls_bpf_head *head)
448 {
449 unsigned int i = 0x80000000;
450 u32 handle;
451
452 do {
453 if (++head->hgen == 0x7FFFFFFF)
454 head->hgen = 1;
455 } while (--i > 0 && cls_bpf_get(tp, head->hgen));
456
457 if (unlikely(i == 0)) {
458 pr_err("Insufficient number of handles\n");
459 handle = 0;
460 } else {
461 handle = head->hgen;
462 }
463
464 return handle;
465 }
466
467 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
468 struct tcf_proto *tp, unsigned long base,
469 u32 handle, struct nlattr **tca,
470 unsigned long *arg, bool ovr)
471 {
472 struct cls_bpf_head *head = rtnl_dereference(tp->root);
473 struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
474 struct nlattr *tb[TCA_BPF_MAX + 1];
475 struct cls_bpf_prog *prog;
476 int ret;
477
478 if (tca[TCA_OPTIONS] == NULL)
479 return -EINVAL;
480
481 ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy);
482 if (ret < 0)
483 return ret;
484
485 prog = kzalloc(sizeof(*prog), GFP_KERNEL);
486 if (!prog)
487 return -ENOBUFS;
488
489 ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
490 if (ret < 0)
491 goto errout;
492
493 if (oldprog) {
494 if (handle && oldprog->handle != handle) {
495 ret = -EINVAL;
496 goto errout;
497 }
498 }
499
500 if (handle == 0)
501 prog->handle = cls_bpf_grab_new_handle(tp, head);
502 else
503 prog->handle = handle;
504 if (prog->handle == 0) {
505 ret = -EINVAL;
506 goto errout;
507 }
508
509 ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE],
510 ovr);
511 if (ret < 0)
512 goto errout;
513
514 ret = cls_bpf_offload(tp, prog, oldprog);
515 if (ret) {
516 __cls_bpf_delete_prog(prog);
517 return ret;
518 }
519
520 if (!tc_in_hw(prog->gen_flags))
521 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
522
523 if (oldprog) {
524 list_replace_rcu(&oldprog->link, &prog->link);
525 tcf_unbind_filter(tp, &oldprog->res);
526 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
527 } else {
528 list_add_rcu(&prog->link, &head->plist);
529 }
530
531 *arg = (unsigned long) prog;
532 return 0;
533
534 errout:
535 tcf_exts_destroy(&prog->exts);
536 kfree(prog);
537 return ret;
538 }
539
540 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
541 struct sk_buff *skb)
542 {
543 struct nlattr *nla;
544
545 if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
546 return -EMSGSIZE;
547
548 nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
549 sizeof(struct sock_filter));
550 if (nla == NULL)
551 return -EMSGSIZE;
552
553 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
554
555 return 0;
556 }
557
558 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
559 struct sk_buff *skb)
560 {
561 struct nlattr *nla;
562
563 if (prog->bpf_name &&
564 nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
565 return -EMSGSIZE;
566
567 nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
568 if (nla == NULL)
569 return -EMSGSIZE;
570
571 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
572
573 return 0;
574 }
575
576 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
577 struct sk_buff *skb, struct tcmsg *tm)
578 {
579 struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
580 struct nlattr *nest;
581 u32 bpf_flags = 0;
582 int ret;
583
584 if (prog == NULL)
585 return skb->len;
586
587 tm->tcm_handle = prog->handle;
588
589 cls_bpf_offload_update_stats(tp, prog);
590
591 nest = nla_nest_start(skb, TCA_OPTIONS);
592 if (nest == NULL)
593 goto nla_put_failure;
594
595 if (prog->res.classid &&
596 nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
597 goto nla_put_failure;
598
599 if (cls_bpf_is_ebpf(prog))
600 ret = cls_bpf_dump_ebpf_info(prog, skb);
601 else
602 ret = cls_bpf_dump_bpf_info(prog, skb);
603 if (ret)
604 goto nla_put_failure;
605
606 if (tcf_exts_dump(skb, &prog->exts) < 0)
607 goto nla_put_failure;
608
609 if (prog->exts_integrated)
610 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
611 if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
612 goto nla_put_failure;
613 if (prog->gen_flags &&
614 nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
615 goto nla_put_failure;
616
617 nla_nest_end(skb, nest);
618
619 if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
620 goto nla_put_failure;
621
622 return skb->len;
623
624 nla_put_failure:
625 nla_nest_cancel(skb, nest);
626 return -1;
627 }
628
629 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
630 {
631 struct cls_bpf_head *head = rtnl_dereference(tp->root);
632 struct cls_bpf_prog *prog;
633
634 list_for_each_entry(prog, &head->plist, link) {
635 if (arg->count < arg->skip)
636 goto skip;
637 if (arg->fn(tp, (unsigned long) prog, arg) < 0) {
638 arg->stop = 1;
639 break;
640 }
641 skip:
642 arg->count++;
643 }
644 }
645
646 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
647 .kind = "bpf",
648 .owner = THIS_MODULE,
649 .classify = cls_bpf_classify,
650 .init = cls_bpf_init,
651 .destroy = cls_bpf_destroy,
652 .get = cls_bpf_get,
653 .change = cls_bpf_change,
654 .delete = cls_bpf_delete,
655 .walk = cls_bpf_walk,
656 .dump = cls_bpf_dump,
657 };
658
659 static int __init cls_bpf_init_mod(void)
660 {
661 return register_tcf_proto_ops(&cls_bpf_ops);
662 }
663
664 static void __exit cls_bpf_exit_mod(void)
665 {
666 unregister_tcf_proto_ops(&cls_bpf_ops);
667 }
668
669 module_init(cls_bpf_init_mod);
670 module_exit(cls_bpf_exit_mod);