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Merge tag 'acpi-4.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[karo-tx-linux.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, bool *last)
278 {
279         struct cls_bpf_head *head = rtnl_dereference(tp->root);
280
281         __cls_bpf_delete(tp, (struct cls_bpf_prog *) arg);
282         *last = list_empty(&head->plist);
283         return 0;
284 }
285
286 static void cls_bpf_destroy(struct tcf_proto *tp)
287 {
288         struct cls_bpf_head *head = rtnl_dereference(tp->root);
289         struct cls_bpf_prog *prog, *tmp;
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 }
296
297 static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
298 {
299         struct cls_bpf_head *head = rtnl_dereference(tp->root);
300         struct cls_bpf_prog *prog;
301         unsigned long ret = 0UL;
302
303         list_for_each_entry(prog, &head->plist, link) {
304                 if (prog->handle == handle) {
305                         ret = (unsigned long) prog;
306                         break;
307                 }
308         }
309
310         return ret;
311 }
312
313 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
314 {
315         struct sock_filter *bpf_ops;
316         struct sock_fprog_kern fprog_tmp;
317         struct bpf_prog *fp;
318         u16 bpf_size, bpf_num_ops;
319         int ret;
320
321         bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
322         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
323                 return -EINVAL;
324
325         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
326         if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
327                 return -EINVAL;
328
329         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
330         if (bpf_ops == NULL)
331                 return -ENOMEM;
332
333         memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
334
335         fprog_tmp.len = bpf_num_ops;
336         fprog_tmp.filter = bpf_ops;
337
338         ret = bpf_prog_create(&fp, &fprog_tmp);
339         if (ret < 0) {
340                 kfree(bpf_ops);
341                 return ret;
342         }
343
344         prog->bpf_ops = bpf_ops;
345         prog->bpf_num_ops = bpf_num_ops;
346         prog->bpf_name = NULL;
347         prog->filter = fp;
348
349         return 0;
350 }
351
352 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
353                                  const struct tcf_proto *tp)
354 {
355         struct bpf_prog *fp;
356         char *name = NULL;
357         u32 bpf_fd;
358
359         bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
360
361         fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
362         if (IS_ERR(fp))
363                 return PTR_ERR(fp);
364
365         if (tb[TCA_BPF_NAME]) {
366                 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
367                 if (!name) {
368                         bpf_prog_put(fp);
369                         return -ENOMEM;
370                 }
371         }
372
373         prog->bpf_ops = NULL;
374         prog->bpf_name = name;
375         prog->filter = fp;
376
377         if (fp->dst_needed && !(tp->q->flags & TCQ_F_INGRESS))
378                 netif_keep_dst(qdisc_dev(tp->q));
379
380         return 0;
381 }
382
383 static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
384                                    struct cls_bpf_prog *prog,
385                                    unsigned long base, struct nlattr **tb,
386                                    struct nlattr *est, bool ovr)
387 {
388         bool is_bpf, is_ebpf, have_exts = false;
389         struct tcf_exts exts;
390         u32 gen_flags = 0;
391         int ret;
392
393         is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
394         is_ebpf = tb[TCA_BPF_FD];
395         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
396                 return -EINVAL;
397
398         ret = tcf_exts_init(&exts, TCA_BPF_ACT, TCA_BPF_POLICE);
399         if (ret < 0)
400                 return ret;
401         ret = tcf_exts_validate(net, tp, tb, est, &exts, ovr);
402         if (ret < 0)
403                 goto errout;
404
405         if (tb[TCA_BPF_FLAGS]) {
406                 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
407
408                 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT) {
409                         ret = -EINVAL;
410                         goto errout;
411                 }
412
413                 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
414         }
415         if (tb[TCA_BPF_FLAGS_GEN]) {
416                 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
417                 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
418                     !tc_flags_valid(gen_flags)) {
419                         ret = -EINVAL;
420                         goto errout;
421                 }
422         }
423
424         prog->exts_integrated = have_exts;
425         prog->gen_flags = gen_flags;
426
427         ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
428                        cls_bpf_prog_from_efd(tb, prog, tp);
429         if (ret < 0)
430                 goto errout;
431
432         if (tb[TCA_BPF_CLASSID]) {
433                 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
434                 tcf_bind_filter(tp, &prog->res, base);
435         }
436
437         tcf_exts_change(tp, &prog->exts, &exts);
438         return 0;
439
440 errout:
441         tcf_exts_destroy(&exts);
442         return ret;
443 }
444
445 static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
446                                    struct cls_bpf_head *head)
447 {
448         unsigned int i = 0x80000000;
449         u32 handle;
450
451         do {
452                 if (++head->hgen == 0x7FFFFFFF)
453                         head->hgen = 1;
454         } while (--i > 0 && cls_bpf_get(tp, head->hgen));
455
456         if (unlikely(i == 0)) {
457                 pr_err("Insufficient number of handles\n");
458                 handle = 0;
459         } else {
460                 handle = head->hgen;
461         }
462
463         return handle;
464 }
465
466 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
467                           struct tcf_proto *tp, unsigned long base,
468                           u32 handle, struct nlattr **tca,
469                           unsigned long *arg, bool ovr)
470 {
471         struct cls_bpf_head *head = rtnl_dereference(tp->root);
472         struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
473         struct nlattr *tb[TCA_BPF_MAX + 1];
474         struct cls_bpf_prog *prog;
475         int ret;
476
477         if (tca[TCA_OPTIONS] == NULL)
478                 return -EINVAL;
479
480         ret = nla_parse_nested(tb, TCA_BPF_MAX, tca[TCA_OPTIONS], bpf_policy,
481                                NULL);
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);