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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Berkeley Packet Filter based traffic classifier
4 *
5 * Might be used to classify traffic through flexible, user-defined and
6 * possibly JIT-ed BPF filters for traffic control as an alternative to
7 * ematches.
8 *
9 * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
10 */
11
12#include <linux/module.h>
13#include <linux/types.h>
14#include <linux/skbuff.h>
15#include <linux/filter.h>
16#include <linux/bpf.h>
17#include <linux/idr.h>
18
19#include <net/rtnetlink.h>
20#include <net/pkt_cls.h>
21#include <net/sock.h>
22
23MODULE_LICENSE("GPL");
24MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
25MODULE_DESCRIPTION("TC BPF based classifier");
26
27#define CLS_BPF_NAME_LEN 256
28#define CLS_BPF_SUPPORTED_GEN_FLAGS \
29 (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
30
31struct cls_bpf_head {
32 struct list_head plist;
33 struct idr handle_idr;
34 struct rcu_head rcu;
35};
36
37struct cls_bpf_prog {
38 struct bpf_prog *filter;
39 struct list_head link;
40 struct tcf_result res;
41 bool exts_integrated;
42 u32 gen_flags;
43 unsigned int in_hw_count;
44 struct tcf_exts exts;
45 u32 handle;
46 u16 bpf_num_ops;
47 struct sock_filter *bpf_ops;
48 const char *bpf_name;
49 struct tcf_proto *tp;
50 struct rcu_work rwork;
51};
52
53static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
54 [TCA_BPF_CLASSID] = { .type = NLA_U32 },
55 [TCA_BPF_FLAGS] = { .type = NLA_U32 },
56 [TCA_BPF_FLAGS_GEN] = { .type = NLA_U32 },
57 [TCA_BPF_FD] = { .type = NLA_U32 },
58 [TCA_BPF_NAME] = { .type = NLA_NUL_STRING,
59 .len = CLS_BPF_NAME_LEN },
60 [TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
61 [TCA_BPF_OPS] = { .type = NLA_BINARY,
62 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
63};
64
65static int cls_bpf_exec_opcode(int code)
66{
67 switch (code) {
68 case TC_ACT_OK:
69 case TC_ACT_SHOT:
70 case TC_ACT_STOLEN:
71 case TC_ACT_TRAP:
72 case TC_ACT_REDIRECT:
73 case TC_ACT_UNSPEC:
74 return code;
75 default:
76 return TC_ACT_UNSPEC;
77 }
78}
79
80static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
81 struct tcf_result *res)
82{
83 struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
84 bool at_ingress = skb_at_tc_ingress(skb);
85 struct cls_bpf_prog *prog;
86 int ret = -1;
87
88 /* Needed here for accessing maps. */
89 rcu_read_lock();
90 list_for_each_entry_rcu(prog, &head->plist, link) {
91 int filter_res;
92
93 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
94
95 if (tc_skip_sw(prog->gen_flags)) {
96 filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
97 } else if (at_ingress) {
98 /* It is safe to push/pull even if skb_shared() */
99 __skb_push(skb, skb->mac_len);
100 bpf_compute_data_pointers(skb);
101 filter_res = BPF_PROG_RUN(prog->filter, skb);
102 __skb_pull(skb, skb->mac_len);
103 } else {
104 bpf_compute_data_pointers(skb);
105 filter_res = BPF_PROG_RUN(prog->filter, skb);
106 }
107
108 if (prog->exts_integrated) {
109 res->class = 0;
110 res->classid = TC_H_MAJ(prog->res.classid) |
111 qdisc_skb_cb(skb)->tc_classid;
112
113 ret = cls_bpf_exec_opcode(filter_res);
114 if (ret == TC_ACT_UNSPEC)
115 continue;
116 break;
117 }
118
119 if (filter_res == 0)
120 continue;
121 if (filter_res != -1) {
122 res->class = 0;
123 res->classid = filter_res;
124 } else {
125 *res = prog->res;
126 }
127
128 ret = tcf_exts_exec(skb, &prog->exts, res);
129 if (ret < 0)
130 continue;
131
132 break;
133 }
134 rcu_read_unlock();
135
136 return ret;
137}
138
139static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
140{
141 return !prog->bpf_ops;
142}
143
144static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
145 struct cls_bpf_prog *oldprog,
146 struct netlink_ext_ack *extack)
147{
148 struct tcf_block *block = tp->chain->block;
149 struct tc_cls_bpf_offload cls_bpf = {};
150 struct cls_bpf_prog *obj;
151 bool skip_sw;
152 int err;
153
154 skip_sw = prog && tc_skip_sw(prog->gen_flags);
155 obj = prog ?: oldprog;
156
157 tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags, extack);
158 cls_bpf.command = TC_CLSBPF_OFFLOAD;
159 cls_bpf.exts = &obj->exts;
160 cls_bpf.prog = prog ? prog->filter : NULL;
161 cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
162 cls_bpf.name = obj->bpf_name;
163 cls_bpf.exts_integrated = obj->exts_integrated;
164
165 if (oldprog && prog)
166 err = tc_setup_cb_replace(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
167 skip_sw, &oldprog->gen_flags,
168 &oldprog->in_hw_count,
169 &prog->gen_flags, &prog->in_hw_count,
170 true);
171 else if (prog)
172 err = tc_setup_cb_add(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
173 skip_sw, &prog->gen_flags,
174 &prog->in_hw_count, true);
175 else
176 err = tc_setup_cb_destroy(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
177 skip_sw, &oldprog->gen_flags,
178 &oldprog->in_hw_count, true);
179
180 if (prog && err) {
181 cls_bpf_offload_cmd(tp, oldprog, prog, extack);
182 return err;
183 }
184
185 if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
186 return -EINVAL;
187
188 return 0;
189}
190
191static u32 cls_bpf_flags(u32 flags)
192{
193 return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
194}
195
196static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
197 struct cls_bpf_prog *oldprog,
198 struct netlink_ext_ack *extack)
199{
200 if (prog && oldprog &&
201 cls_bpf_flags(prog->gen_flags) !=
202 cls_bpf_flags(oldprog->gen_flags))
203 return -EINVAL;
204
205 if (prog && tc_skip_hw(prog->gen_flags))
206 prog = NULL;
207 if (oldprog && tc_skip_hw(oldprog->gen_flags))
208 oldprog = NULL;
209 if (!prog && !oldprog)
210 return 0;
211
212 return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
213}
214
215static void cls_bpf_stop_offload(struct tcf_proto *tp,
216 struct cls_bpf_prog *prog,
217 struct netlink_ext_ack *extack)
218{
219 int err;
220
221 err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
222 if (err)
223 pr_err("Stopping hardware offload failed: %d\n", err);
224}
225
226static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
227 struct cls_bpf_prog *prog)
228{
229 struct tcf_block *block = tp->chain->block;
230 struct tc_cls_bpf_offload cls_bpf = {};
231
232 tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
233 cls_bpf.command = TC_CLSBPF_STATS;
234 cls_bpf.exts = &prog->exts;
235 cls_bpf.prog = prog->filter;
236 cls_bpf.name = prog->bpf_name;
237 cls_bpf.exts_integrated = prog->exts_integrated;
238
239 tc_setup_cb_call(block, TC_SETUP_CLSBPF, &cls_bpf, false, true);
240}
241
242static int cls_bpf_init(struct tcf_proto *tp)
243{
244 struct cls_bpf_head *head;
245
246 head = kzalloc(sizeof(*head), GFP_KERNEL);
247 if (head == NULL)
248 return -ENOBUFS;
249
250 INIT_LIST_HEAD_RCU(&head->plist);
251 idr_init(&head->handle_idr);
252 rcu_assign_pointer(tp->root, head);
253
254 return 0;
255}
256
257static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
258{
259 if (cls_bpf_is_ebpf(prog))
260 bpf_prog_put(prog->filter);
261 else
262 bpf_prog_destroy(prog->filter);
263
264 kfree(prog->bpf_name);
265 kfree(prog->bpf_ops);
266}
267
268static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
269{
270 tcf_exts_destroy(&prog->exts);
271 tcf_exts_put_net(&prog->exts);
272
273 cls_bpf_free_parms(prog);
274 kfree(prog);
275}
276
277static void cls_bpf_delete_prog_work(struct work_struct *work)
278{
279 struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
280 struct cls_bpf_prog,
281 rwork);
282 rtnl_lock();
283 __cls_bpf_delete_prog(prog);
284 rtnl_unlock();
285}
286
287static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
288 struct netlink_ext_ack *extack)
289{
290 struct cls_bpf_head *head = rtnl_dereference(tp->root);
291
292 idr_remove(&head->handle_idr, prog->handle);
293 cls_bpf_stop_offload(tp, prog, extack);
294 list_del_rcu(&prog->link);
295 tcf_unbind_filter(tp, &prog->res);
296 if (tcf_exts_get_net(&prog->exts))
297 tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
298 else
299 __cls_bpf_delete_prog(prog);
300}
301
302static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
303 bool rtnl_held, struct netlink_ext_ack *extack)
304{
305 struct cls_bpf_head *head = rtnl_dereference(tp->root);
306
307 __cls_bpf_delete(tp, arg, extack);
308 *last = list_empty(&head->plist);
309 return 0;
310}
311
312static void cls_bpf_destroy(struct tcf_proto *tp, bool rtnl_held,
313 struct netlink_ext_ack *extack)
314{
315 struct cls_bpf_head *head = rtnl_dereference(tp->root);
316 struct cls_bpf_prog *prog, *tmp;
317
318 list_for_each_entry_safe(prog, tmp, &head->plist, link)
319 __cls_bpf_delete(tp, prog, extack);
320
321 idr_destroy(&head->handle_idr);
322 kfree_rcu(head, rcu);
323}
324
325static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
326{
327 struct cls_bpf_head *head = rtnl_dereference(tp->root);
328 struct cls_bpf_prog *prog;
329
330 list_for_each_entry(prog, &head->plist, link) {
331 if (prog->handle == handle)
332 return prog;
333 }
334
335 return NULL;
336}
337
338static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
339{
340 struct sock_filter *bpf_ops;
341 struct sock_fprog_kern fprog_tmp;
342 struct bpf_prog *fp;
343 u16 bpf_size, bpf_num_ops;
344 int ret;
345
346 bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
347 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
348 return -EINVAL;
349
350 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
351 if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
352 return -EINVAL;
353
354 bpf_ops = kmemdup(nla_data(tb[TCA_BPF_OPS]), bpf_size, GFP_KERNEL);
355 if (bpf_ops == NULL)
356 return -ENOMEM;
357
358 fprog_tmp.len = bpf_num_ops;
359 fprog_tmp.filter = bpf_ops;
360
361 ret = bpf_prog_create(&fp, &fprog_tmp);
362 if (ret < 0) {
363 kfree(bpf_ops);
364 return ret;
365 }
366
367 prog->bpf_ops = bpf_ops;
368 prog->bpf_num_ops = bpf_num_ops;
369 prog->bpf_name = NULL;
370 prog->filter = fp;
371
372 return 0;
373}
374
375static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
376 u32 gen_flags, const struct tcf_proto *tp)
377{
378 struct bpf_prog *fp;
379 char *name = NULL;
380 bool skip_sw;
381 u32 bpf_fd;
382
383 bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
384 skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
385
386 fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
387 if (IS_ERR(fp))
388 return PTR_ERR(fp);
389
390 if (tb[TCA_BPF_NAME]) {
391 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
392 if (!name) {
393 bpf_prog_put(fp);
394 return -ENOMEM;
395 }
396 }
397
398 prog->bpf_ops = NULL;
399 prog->bpf_name = name;
400 prog->filter = fp;
401
402 if (fp->dst_needed)
403 tcf_block_netif_keep_dst(tp->chain->block);
404
405 return 0;
406}
407
408static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
409 struct cls_bpf_prog *prog, unsigned long base,
410 struct nlattr **tb, struct nlattr *est, bool ovr,
411 struct netlink_ext_ack *extack)
412{
413 bool is_bpf, is_ebpf, have_exts = false;
414 u32 gen_flags = 0;
415 int ret;
416
417 is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
418 is_ebpf = tb[TCA_BPF_FD];
419 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
420 return -EINVAL;
421
422 ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr, true,
423 extack);
424 if (ret < 0)
425 return ret;
426
427 if (tb[TCA_BPF_FLAGS]) {
428 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
429
430 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
431 return -EINVAL;
432
433 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
434 }
435 if (tb[TCA_BPF_FLAGS_GEN]) {
436 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
437 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
438 !tc_flags_valid(gen_flags))
439 return -EINVAL;
440 }
441
442 prog->exts_integrated = have_exts;
443 prog->gen_flags = gen_flags;
444
445 ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
446 cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
447 if (ret < 0)
448 return ret;
449
450 if (tb[TCA_BPF_CLASSID]) {
451 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
452 tcf_bind_filter(tp, &prog->res, base);
453 }
454
455 return 0;
456}
457
458static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
459 struct tcf_proto *tp, unsigned long base,
460 u32 handle, struct nlattr **tca,
461 void **arg, bool ovr, bool rtnl_held,
462 struct netlink_ext_ack *extack)
463{
464 struct cls_bpf_head *head = rtnl_dereference(tp->root);
465 struct cls_bpf_prog *oldprog = *arg;
466 struct nlattr *tb[TCA_BPF_MAX + 1];
467 struct cls_bpf_prog *prog;
468 int ret;
469
470 if (tca[TCA_OPTIONS] == NULL)
471 return -EINVAL;
472
473 ret = nla_parse_nested_deprecated(tb, TCA_BPF_MAX, tca[TCA_OPTIONS],
474 bpf_policy, NULL);
475 if (ret < 0)
476 return ret;
477
478 prog = kzalloc(sizeof(*prog), GFP_KERNEL);
479 if (!prog)
480 return -ENOBUFS;
481
482 ret = tcf_exts_init(&prog->exts, net, TCA_BPF_ACT, TCA_BPF_POLICE);
483 if (ret < 0)
484 goto errout;
485
486 if (oldprog) {
487 if (handle && oldprog->handle != handle) {
488 ret = -EINVAL;
489 goto errout;
490 }
491 }
492
493 if (handle == 0) {
494 handle = 1;
495 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
496 INT_MAX, GFP_KERNEL);
497 } else if (!oldprog) {
498 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
499 handle, GFP_KERNEL);
500 }
501
502 if (ret)
503 goto errout;
504 prog->handle = handle;
505
506 ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
507 extack);
508 if (ret < 0)
509 goto errout_idr;
510
511 ret = cls_bpf_offload(tp, prog, oldprog, extack);
512 if (ret)
513 goto errout_parms;
514
515 if (!tc_in_hw(prog->gen_flags))
516 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
517
518 if (oldprog) {
519 idr_replace(&head->handle_idr, prog, handle);
520 list_replace_rcu(&oldprog->link, &prog->link);
521 tcf_unbind_filter(tp, &oldprog->res);
522 tcf_exts_get_net(&oldprog->exts);
523 tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
524 } else {
525 list_add_rcu(&prog->link, &head->plist);
526 }
527
528 *arg = prog;
529 return 0;
530
531errout_parms:
532 cls_bpf_free_parms(prog);
533errout_idr:
534 if (!oldprog)
535 idr_remove(&head->handle_idr, prog->handle);
536errout:
537 tcf_exts_destroy(&prog->exts);
538 kfree(prog);
539 return ret;
540}
541
542static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
543 struct sk_buff *skb)
544{
545 struct nlattr *nla;
546
547 if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
548 return -EMSGSIZE;
549
550 nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
551 sizeof(struct sock_filter));
552 if (nla == NULL)
553 return -EMSGSIZE;
554
555 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
556
557 return 0;
558}
559
560static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
561 struct sk_buff *skb)
562{
563 struct nlattr *nla;
564
565 if (prog->bpf_name &&
566 nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
567 return -EMSGSIZE;
568
569 if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
570 return -EMSGSIZE;
571
572 nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
573 if (nla == NULL)
574 return -EMSGSIZE;
575
576 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
577
578 return 0;
579}
580
581static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
582 struct sk_buff *skb, struct tcmsg *tm, bool rtnl_held)
583{
584 struct cls_bpf_prog *prog = fh;
585 struct nlattr *nest;
586 u32 bpf_flags = 0;
587 int ret;
588
589 if (prog == NULL)
590 return skb->len;
591
592 tm->tcm_handle = prog->handle;
593
594 cls_bpf_offload_update_stats(tp, prog);
595
596 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
597 if (nest == NULL)
598 goto nla_put_failure;
599
600 if (prog->res.classid &&
601 nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
602 goto nla_put_failure;
603
604 if (cls_bpf_is_ebpf(prog))
605 ret = cls_bpf_dump_ebpf_info(prog, skb);
606 else
607 ret = cls_bpf_dump_bpf_info(prog, skb);
608 if (ret)
609 goto nla_put_failure;
610
611 if (tcf_exts_dump(skb, &prog->exts) < 0)
612 goto nla_put_failure;
613
614 if (prog->exts_integrated)
615 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
616 if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
617 goto nla_put_failure;
618 if (prog->gen_flags &&
619 nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
620 goto nla_put_failure;
621
622 nla_nest_end(skb, nest);
623
624 if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
625 goto nla_put_failure;
626
627 return skb->len;
628
629nla_put_failure:
630 nla_nest_cancel(skb, nest);
631 return -1;
632}
633
634static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
635{
636 struct cls_bpf_prog *prog = fh;
637
638 if (prog && prog->res.classid == classid)
639 prog->res.class = cl;
640}
641
642static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg,
643 bool rtnl_held)
644{
645 struct cls_bpf_head *head = rtnl_dereference(tp->root);
646 struct cls_bpf_prog *prog;
647
648 list_for_each_entry(prog, &head->plist, link) {
649 if (arg->count < arg->skip)
650 goto skip;
651 if (arg->fn(tp, prog, arg) < 0) {
652 arg->stop = 1;
653 break;
654 }
655skip:
656 arg->count++;
657 }
658}
659
660static int cls_bpf_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
661 void *cb_priv, struct netlink_ext_ack *extack)
662{
663 struct cls_bpf_head *head = rtnl_dereference(tp->root);
664 struct tcf_block *block = tp->chain->block;
665 struct tc_cls_bpf_offload cls_bpf = {};
666 struct cls_bpf_prog *prog;
667 int err;
668
669 list_for_each_entry(prog, &head->plist, link) {
670 if (tc_skip_hw(prog->gen_flags))
671 continue;
672
673 tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags,
674 extack);
675 cls_bpf.command = TC_CLSBPF_OFFLOAD;
676 cls_bpf.exts = &prog->exts;
677 cls_bpf.prog = add ? prog->filter : NULL;
678 cls_bpf.oldprog = add ? NULL : prog->filter;
679 cls_bpf.name = prog->bpf_name;
680 cls_bpf.exts_integrated = prog->exts_integrated;
681
682 err = tc_setup_cb_reoffload(block, tp, add, cb, TC_SETUP_CLSBPF,
683 &cls_bpf, cb_priv, &prog->gen_flags,
684 &prog->in_hw_count);
685 if (err)
686 return err;
687 }
688
689 return 0;
690}
691
692static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
693 .kind = "bpf",
694 .owner = THIS_MODULE,
695 .classify = cls_bpf_classify,
696 .init = cls_bpf_init,
697 .destroy = cls_bpf_destroy,
698 .get = cls_bpf_get,
699 .change = cls_bpf_change,
700 .delete = cls_bpf_delete,
701 .walk = cls_bpf_walk,
702 .reoffload = cls_bpf_reoffload,
703 .dump = cls_bpf_dump,
704 .bind_class = cls_bpf_bind_class,
705};
706
707static int __init cls_bpf_init_mod(void)
708{
709 return register_tcf_proto_ops(&cls_bpf_ops);
710}
711
712static void __exit cls_bpf_exit_mod(void)
713{
714 unregister_tcf_proto_ops(&cls_bpf_ops);
715}
716
717module_init(cls_bpf_init_mod);
718module_exit(cls_bpf_exit_mod);
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
25MODULE_LICENSE("GPL");
26MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
27MODULE_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
33struct cls_bpf_head {
34 struct list_head plist;
35 u32 hgen;
36 struct rcu_head rcu;
37};
38
39struct 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
55static 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
67static 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
81static 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
140static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
141{
142 return !prog->bpf_ops;
143}
144
145static 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
152 offload.type = TC_SETUP_CLSBPF;
153 offload.cls_bpf = &bpf_offload;
154
155 bpf_offload.command = cmd;
156 bpf_offload.exts = &prog->exts;
157 bpf_offload.prog = prog->filter;
158 bpf_offload.name = prog->bpf_name;
159 bpf_offload.exts_integrated = prog->exts_integrated;
160 bpf_offload.gen_flags = prog->gen_flags;
161
162 return dev->netdev_ops->ndo_setup_tc(dev, tp->q->handle,
163 tp->protocol, &offload);
164}
165
166static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
167 struct cls_bpf_prog *oldprog)
168{
169 struct net_device *dev = tp->q->dev_queue->dev;
170 struct cls_bpf_prog *obj = prog;
171 enum tc_clsbpf_command cmd;
172 bool skip_sw;
173 int ret;
174
175 skip_sw = tc_skip_sw(prog->gen_flags) ||
176 (oldprog && tc_skip_sw(oldprog->gen_flags));
177
178 if (oldprog && oldprog->offloaded) {
179 if (tc_should_offload(dev, tp, prog->gen_flags)) {
180 cmd = TC_CLSBPF_REPLACE;
181 } else if (!tc_skip_sw(prog->gen_flags)) {
182 obj = oldprog;
183 cmd = TC_CLSBPF_DESTROY;
184 } else {
185 return -EINVAL;
186 }
187 } else {
188 if (!tc_should_offload(dev, tp, prog->gen_flags))
189 return skip_sw ? -EINVAL : 0;
190 cmd = TC_CLSBPF_ADD;
191 }
192
193 ret = cls_bpf_offload_cmd(tp, obj, cmd);
194 if (ret)
195 return skip_sw ? ret : 0;
196
197 obj->offloaded = true;
198 if (oldprog)
199 oldprog->offloaded = false;
200
201 return 0;
202}
203
204static void cls_bpf_stop_offload(struct tcf_proto *tp,
205 struct cls_bpf_prog *prog)
206{
207 int err;
208
209 if (!prog->offloaded)
210 return;
211
212 err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
213 if (err) {
214 pr_err("Stopping hardware offload failed: %d\n", err);
215 return;
216 }
217
218 prog->offloaded = false;
219}
220
221static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
222 struct cls_bpf_prog *prog)
223{
224 if (!prog->offloaded)
225 return;
226
227 cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS);
228}
229
230static int cls_bpf_init(struct tcf_proto *tp)
231{
232 struct cls_bpf_head *head;
233
234 head = kzalloc(sizeof(*head), GFP_KERNEL);
235 if (head == NULL)
236 return -ENOBUFS;
237
238 INIT_LIST_HEAD_RCU(&head->plist);
239 rcu_assign_pointer(tp->root, head);
240
241 return 0;
242}
243
244static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
245{
246 tcf_exts_destroy(&prog->exts);
247
248 if (cls_bpf_is_ebpf(prog))
249 bpf_prog_put(prog->filter);
250 else
251 bpf_prog_destroy(prog->filter);
252
253 kfree(prog->bpf_name);
254 kfree(prog->bpf_ops);
255 kfree(prog);
256}
257
258static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
259{
260 __cls_bpf_delete_prog(container_of(rcu, struct cls_bpf_prog, rcu));
261}
262
263static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
264{
265 cls_bpf_stop_offload(tp, prog);
266 list_del_rcu(&prog->link);
267 tcf_unbind_filter(tp, &prog->res);
268 call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
269}
270
271static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
272{
273 __cls_bpf_delete(tp, (struct cls_bpf_prog *) arg);
274 return 0;
275}
276
277static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
278{
279 struct cls_bpf_head *head = rtnl_dereference(tp->root);
280 struct cls_bpf_prog *prog, *tmp;
281
282 if (!force && !list_empty(&head->plist))
283 return false;
284
285 list_for_each_entry_safe(prog, tmp, &head->plist, link)
286 __cls_bpf_delete(tp, prog);
287
288 kfree_rcu(head, rcu);
289 return true;
290}
291
292static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
293{
294 struct cls_bpf_head *head = rtnl_dereference(tp->root);
295 struct cls_bpf_prog *prog;
296 unsigned long ret = 0UL;
297
298 list_for_each_entry(prog, &head->plist, link) {
299 if (prog->handle == handle) {
300 ret = (unsigned long) prog;
301 break;
302 }
303 }
304
305 return ret;
306}
307
308static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
309{
310 struct sock_filter *bpf_ops;
311 struct sock_fprog_kern fprog_tmp;
312 struct bpf_prog *fp;
313 u16 bpf_size, bpf_num_ops;
314 int ret;
315
316 bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
317 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
318 return -EINVAL;
319
320 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
321 if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
322 return -EINVAL;
323
324 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
325 if (bpf_ops == NULL)
326 return -ENOMEM;
327
328 memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
329
330 fprog_tmp.len = bpf_num_ops;
331 fprog_tmp.filter = bpf_ops;
332
333 ret = bpf_prog_create(&fp, &fprog_tmp);
334 if (ret < 0) {
335 kfree(bpf_ops);
336 return ret;
337 }
338
339 prog->bpf_ops = bpf_ops;
340 prog->bpf_num_ops = bpf_num_ops;
341 prog->bpf_name = NULL;
342 prog->filter = fp;
343
344 return 0;
345}
346
347static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
348 const struct tcf_proto *tp)
349{
350 struct bpf_prog *fp;
351 char *name = NULL;
352 u32 bpf_fd;
353
354 bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
355
356 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
357 if (IS_ERR(fp))
358 return PTR_ERR(fp);
359
360 if (tb[TCA_BPF_NAME]) {
361 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
362 if (!name) {
363 bpf_prog_put(fp);
364 return -ENOMEM;
365 }
366 }
367
368 prog->bpf_ops = NULL;
369 prog->bpf_name = name;
370 prog->filter = fp;
371
372 if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
373 netif_keep_dst(qdisc_dev(tp->q));
374
375 return 0;
376}
377
378static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
379 struct cls_bpf_prog *prog,
380 unsigned long base, struct nlattr **tb,
381 struct nlattr *est, bool ovr)
382{
383 bool is_bpf, is_ebpf, have_exts = false;
384 struct tcf_exts exts;
385 u32 gen_flags = 0;
386 int ret;
387
388 is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
389 is_ebpf = tb[TCA_BPF_FD];
390 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
391 return -EINVAL;
392
393 ret = tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
394 if (ret < 0)
395 return ret;
396 ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
397 if (ret < 0)
398 goto errout;
399
400 if (tb[TCA_BPF_FLAGS]) {
401 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
402
403 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
404 ret = -EINVAL;
405 goto errout;
406 }
407
408 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
409 }
410 if (tb[TCA_BPF_FLAGS_GEN]) {
411 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
412 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
413 !tc_flags_valid(gen_flags)) {
414 ret = -EINVAL;
415 goto errout;
416 }
417 }
418
419 prog->exts_integrated = have_exts;
420 prog->gen_flags = gen_flags;
421
422 ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
423 cls_bpf_prog_from_efd(tb, prog, tp);
424 if (ret < 0)
425 goto errout;
426
427 if (tb[TCA_BPF_CLASSID]) {
428 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
429 tcf_bind_filter(tp, &prog->res, base);
430 }
431
432 tcf_exts_change(tp, &prog->exts, &exts);
433 return 0;
434
435errout:
436 tcf_exts_destroy(&exts);
437 return ret;
438}
439
440static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
441 struct cls_bpf_head *head)
442{
443 unsigned int i = 0x80000000;
444 u32 handle;
445
446 do {
447 if (++head->hgen == 0x7FFFFFFF)
448 head->hgen = 1;
449 } while (--i > 0 && cls_bpf_get(tp, head->hgen));
450
451 if (unlikely(i == 0)) {
452 pr_err("Insufficient number of handles\n");
453 handle = 0;
454 } else {
455 handle = head->hgen;
456 }
457
458 return handle;
459}
460
461static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
462 struct tcf_proto *tp, unsigned long base,
463 u32 handle, struct nlattr **tca,
464 unsigned long *arg, bool ovr)
465{
466 struct cls_bpf_head *head = rtnl_dereference(tp->root);
467 struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
468 struct nlattr *tb[TCA_BPF_MAX + 1];
469 struct cls_bpf_prog *prog;
470 int ret;
471
472 if (tca[TCA_OPTIONS] == NULL)
473 return -EINVAL;
474
475 ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy);
476 if (ret < 0)
477 return ret;
478
479 prog = kzalloc(sizeof(*prog), GFP_KERNEL);
480 if (!prog)
481 return -ENOBUFS;
482
483 ret = tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
484 if (ret < 0)
485 goto errout;
486
487 if (oldprog) {
488 if (handle && oldprog->handle != handle) {
489 ret = -EINVAL;
490 goto errout;
491 }
492 }
493
494 if (handle == 0)
495 prog->handle = cls_bpf_grab_new_handle(tp, head);
496 else
497 prog->handle = handle;
498 if (prog->handle == 0) {
499 ret = -EINVAL;
500 goto errout;
501 }
502
503 ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE],
504 ovr);
505 if (ret < 0)
506 goto errout;
507
508 ret = cls_bpf_offload(tp, prog, oldprog);
509 if (ret) {
510 __cls_bpf_delete_prog(prog);
511 return ret;
512 }
513
514 if (oldprog) {
515 list_replace_rcu(&oldprog->link, &prog->link);
516 tcf_unbind_filter(tp, &oldprog->res);
517 call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
518 } else {
519 list_add_rcu(&prog->link, &head->plist);
520 }
521
522 *arg = (unsigned long) prog;
523 return 0;
524
525errout:
526 tcf_exts_destroy(&prog->exts);
527 kfree(prog);
528 return ret;
529}
530
531static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
532 struct sk_buff *skb)
533{
534 struct nlattr *nla;
535
536 if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
537 return -EMSGSIZE;
538
539 nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
540 sizeof(struct sock_filter));
541 if (nla == NULL)
542 return -EMSGSIZE;
543
544 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
545
546 return 0;
547}
548
549static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
550 struct sk_buff *skb)
551{
552 struct nlattr *nla;
553
554 if (prog->bpf_name &&
555 nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
556 return -EMSGSIZE;
557
558 nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
559 if (nla == NULL)
560 return -EMSGSIZE;
561
562 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
563
564 return 0;
565}
566
567static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
568 struct sk_buff *skb, struct tcmsg *tm)
569{
570 struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
571 struct nlattr *nest;
572 u32 bpf_flags = 0;
573 int ret;
574
575 if (prog == NULL)
576 return skb->len;
577
578 tm->tcm_handle = prog->handle;
579
580 cls_bpf_offload_update_stats(tp, prog);
581
582 nest = nla_nest_start(skb, TCA_OPTIONS);
583 if (nest == NULL)
584 goto nla_put_failure;
585
586 if (prog->res.classid &&
587 nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
588 goto nla_put_failure;
589
590 if (cls_bpf_is_ebpf(prog))
591 ret = cls_bpf_dump_ebpf_info(prog, skb);
592 else
593 ret = cls_bpf_dump_bpf_info(prog, skb);
594 if (ret)
595 goto nla_put_failure;
596
597 if (tcf_exts_dump(skb, &prog->exts) < 0)
598 goto nla_put_failure;
599
600 if (prog->exts_integrated)
601 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
602 if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
603 goto nla_put_failure;
604 if (prog->gen_flags &&
605 nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
606 goto nla_put_failure;
607
608 nla_nest_end(skb, nest);
609
610 if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
611 goto nla_put_failure;
612
613 return skb->len;
614
615nla_put_failure:
616 nla_nest_cancel(skb, nest);
617 return -1;
618}
619
620static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
621{
622 struct cls_bpf_head *head = rtnl_dereference(tp->root);
623 struct cls_bpf_prog *prog;
624
625 list_for_each_entry(prog, &head->plist, link) {
626 if (arg->count < arg->skip)
627 goto skip;
628 if (arg->fn(tp, (unsigned long) prog, arg) < 0) {
629 arg->stop = 1;
630 break;
631 }
632skip:
633 arg->count++;
634 }
635}
636
637static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
638 .kind = "bpf",
639 .owner = THIS_MODULE,
640 .classify = cls_bpf_classify,
641 .init = cls_bpf_init,
642 .destroy = cls_bpf_destroy,
643 .get = cls_bpf_get,
644 .change = cls_bpf_change,
645 .delete = cls_bpf_delete,
646 .walk = cls_bpf_walk,
647 .dump = cls_bpf_dump,
648};
649
650static int __init cls_bpf_init_mod(void)
651{
652 return register_tcf_proto_ops(&cls_bpf_ops);
653}
654
655static void __exit cls_bpf_exit_mod(void)
656{
657 unregister_tcf_proto_ops(&cls_bpf_ops);
658}
659
660module_init(cls_bpf_init_mod);
661module_exit(cls_bpf_exit_mod);