1
2
3
4
5
6
7
8
9
10
11
12
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
31struct cls_bpf_head {
32 struct list_head plist;
33 u32 hgen;
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 struct tcf_exts exts;
42 u32 handle;
43 union {
44 u32 bpf_fd;
45 u16 bpf_num_ops;
46 };
47 struct sock_filter *bpf_ops;
48 const char *bpf_name;
49 struct tcf_proto *tp;
50 struct rcu_head rcu;
51};
52
53static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
54 [TCA_BPF_CLASSID] = { .type = NLA_U32 },
55 [TCA_BPF_FD] = { .type = NLA_U32 },
56 [TCA_BPF_NAME] = { .type = NLA_NUL_STRING, .len = CLS_BPF_NAME_LEN },
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
62static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
63 struct tcf_result *res)
64{
65 struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
66 struct cls_bpf_prog *prog;
67 int ret = -1;
68
69 if (unlikely(!skb_mac_header_was_set(skb)))
70 return -1;
71
72
73 rcu_read_lock();
74 list_for_each_entry_rcu(prog, &head->plist, link) {
75 int filter_res = BPF_PROG_RUN(prog->filter, skb);
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
88 break;
89 }
90 rcu_read_unlock();
91
92 return ret;
93}
94
95static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
96{
97 return !prog->bpf_ops;
98}
99
100static 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
108 INIT_LIST_HEAD_RCU(&head->plist);
109 rcu_assign_pointer(tp->root, head);
110
111 return 0;
112}
113
114static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
115{
116 tcf_exts_destroy(&prog->exts);
117
118 if (cls_bpf_is_ebpf(prog))
119 bpf_prog_put(prog->filter);
120 else
121 bpf_prog_destroy(prog->filter);
122
123 kfree(prog->bpf_name);
124 kfree(prog->bpf_ops);
125 kfree(prog);
126}
127
128static 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
135static int cls_bpf_delete(struct tcf_proto *tp, unsigned long arg)
136{
137 struct cls_bpf_prog *prog = (struct cls_bpf_prog *) arg;
138
139 list_del_rcu(&prog->link);
140 tcf_unbind_filter(tp, &prog->res);
141 call_rcu(&prog->rcu, __cls_bpf_delete_prog);
142
143 return 0;
144}
145
146static bool cls_bpf_destroy(struct tcf_proto *tp, bool force)
147{
148 struct cls_bpf_head *head = rtnl_dereference(tp->root);
149 struct cls_bpf_prog *prog, *tmp;
150
151 if (!force && !list_empty(&head->plist))
152 return false;
153
154 list_for_each_entry_safe(prog, tmp, &head->plist, link) {
155 list_del_rcu(&prog->link);
156 tcf_unbind_filter(tp, &prog->res);
157 call_rcu(&prog->rcu, __cls_bpf_delete_prog);
158 }
159
160 RCU_INIT_POINTER(tp->root, NULL);
161 kfree_rcu(head, rcu);
162 return true;
163}
164
165static unsigned long cls_bpf_get(struct tcf_proto *tp, u32 handle)
166{
167 struct cls_bpf_head *head = rtnl_dereference(tp->root);
168 struct cls_bpf_prog *prog;
169 unsigned long ret = 0UL;
170
171 if (head == NULL)
172 return 0UL;
173
174 list_for_each_entry(prog, &head->plist, link) {
175 if (prog->handle == handle) {
176 ret = (unsigned long) prog;
177 break;
178 }
179 }
180
181 return ret;
182}
183
184static int cls_bpf_prog_from_ops(struct nlattr **tb,
185 struct cls_bpf_prog *prog, u32 classid)
186{
187 struct sock_filter *bpf_ops;
188 struct sock_fprog_kern fprog_tmp;
189 struct bpf_prog *fp;
190 u16 bpf_size, bpf_num_ops;
191 int ret;
192
193 bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
194 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
195 return -EINVAL;
196
197 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
198 if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
199 return -EINVAL;
200
201 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
202 if (bpf_ops == NULL)
203 return -ENOMEM;
204
205 memcpy(bpf_ops, nla_data(tb[TCA_BPF_OPS]), bpf_size);
206
207 fprog_tmp.len = bpf_num_ops;
208 fprog_tmp.filter = bpf_ops;
209
210 ret = bpf_prog_create(&fp, &fprog_tmp);
211 if (ret < 0) {
212 kfree(bpf_ops);
213 return ret;
214 }
215
216 prog->bpf_ops = bpf_ops;
217 prog->bpf_num_ops = bpf_num_ops;
218 prog->bpf_name = NULL;
219
220 prog->filter = fp;
221 prog->res.classid = classid;
222
223 return 0;
224}
225
226static 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
264static 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
295 tcf_bind_filter(tp, &prog->res, base);
296 tcf_exts_change(tp, &prog->exts, &exts);
297
298 return 0;
299}
300
301static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp,
302 struct cls_bpf_head *head)
303{
304 unsigned int i = 0x80000000;
305 u32 handle;
306
307 do {
308 if (++head->hgen == 0x7FFFFFFF)
309 head->hgen = 1;
310 } while (--i > 0 && cls_bpf_get(tp, head->hgen));
311
312 if (unlikely(i == 0)) {
313 pr_err("Insufficient number of handles\n");
314 handle = 0;
315 } else {
316 handle = head->hgen;
317 }
318
319 return handle;
320}
321
322static 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,
325 unsigned long *arg, bool ovr)
326{
327 struct cls_bpf_head *head = rtnl_dereference(tp->root);
328 struct cls_bpf_prog *oldprog = (struct cls_bpf_prog *) *arg;
329 struct nlattr *tb[TCA_BPF_MAX + 1];
330 struct cls_bpf_prog *prog;
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
340 prog = kzalloc(sizeof(*prog), GFP_KERNEL);
341 if (!prog)
342 return -ENOBUFS;
343
344 tcf_exts_init(&prog->exts, TCA_BPF_ACT, TCA_BPF_POLICE);
345
346 if (oldprog) {
347 if (handle && oldprog->handle != handle) {
348 ret = -EINVAL;
349 goto errout;
350 }
351 }
352
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
362 ret = cls_bpf_modify_existing(net, tp, prog, base, tb, tca[TCA_RATE], ovr);
363 if (ret < 0)
364 goto errout;
365
366 if (oldprog) {
367 list_replace_rcu(&prog->link, &oldprog->link);
368 tcf_unbind_filter(tp, &oldprog->res);
369 call_rcu(&oldprog->rcu, __cls_bpf_delete_prog);
370 } else {
371 list_add_rcu(&prog->link, &head->plist);
372 }
373
374 *arg = (unsigned long) prog;
375 return 0;
376errout:
377 kfree(prog);
378
379 return ret;
380}
381
382static 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
400static 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
413static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
414 struct sk_buff *skb, struct tcmsg *tm)
415{
416 struct cls_bpf_prog *prog = (struct cls_bpf_prog *) fh;
417 struct nlattr *nest;
418 int ret;
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;
431
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)
437 goto nla_put_failure;
438
439 if (tcf_exts_dump(skb, &prog->exts) < 0)
440 goto nla_put_failure;
441
442 nla_nest_end(skb, nest);
443
444 if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
445 goto nla_put_failure;
446
447 return skb->len;
448
449nla_put_failure:
450 nla_nest_cancel(skb, nest);
451 return -1;
452}
453
454static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg)
455{
456 struct cls_bpf_head *head = rtnl_dereference(tp->root);
457 struct cls_bpf_prog *prog;
458
459 list_for_each_entry(prog, &head->plist, link) {
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 }
466skip:
467 arg->count++;
468 }
469}
470
471static 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,
478 .change = cls_bpf_change,
479 .delete = cls_bpf_delete,
480 .walk = cls_bpf_walk,
481 .dump = cls_bpf_dump,
482};
483
484static int __init cls_bpf_init_mod(void)
485{
486 return register_tcf_proto_ops(&cls_bpf_ops);
487}
488
489static void __exit cls_bpf_exit_mod(void)
490{
491 unregister_tcf_proto_ops(&cls_bpf_ops);
492}
493
494module_init(cls_bpf_init_mod);
495module_exit(cls_bpf_exit_mod);
496
