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6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/kernel.h>
9#include <linux/skbuff.h>
10#include <linux/rtnetlink.h>
11#include <linux/filter.h>
12#include <linux/bpf.h>
13
14#include <net/netlink.h>
15#include <net/sock.h>
16#include <net/pkt_sched.h>
17#include <net/pkt_cls.h>
18
19#include <linux/tc_act/tc_bpf.h>
20#include <net/tc_act/tc_bpf.h>
21
22#define ACT_BPF_NAME_LEN 256
23
24struct tcf_bpf_cfg {
25 struct bpf_prog *filter;
26 struct sock_filter *bpf_ops;
27 const char *bpf_name;
28 u16 bpf_num_ops;
29 bool is_ebpf;
30};
31
32static unsigned int bpf_net_id;
33static struct tc_action_ops act_bpf_ops;
34
35static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act,
36 struct tcf_result *res)
37{
38 bool at_ingress = skb_at_tc_ingress(skb);
39 struct tcf_bpf *prog = to_bpf(act);
40 struct bpf_prog *filter;
41 int action, filter_res;
42
43 tcf_lastuse_update(&prog->tcf_tm);
44 bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
45
46 rcu_read_lock();
47 filter = rcu_dereference(prog->filter);
48 if (at_ingress) {
49 __skb_push(skb, skb->mac_len);
50 bpf_compute_data_pointers(skb);
51 filter_res = BPF_PROG_RUN(filter, skb);
52 __skb_pull(skb, skb->mac_len);
53 } else {
54 bpf_compute_data_pointers(skb);
55 filter_res = BPF_PROG_RUN(filter, skb);
56 }
57 if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK)
58 skb_orphan(skb);
59 rcu_read_unlock();
60
61
62
63
64
65
66
67
68
69
70
71 switch (filter_res) {
72 case TC_ACT_PIPE:
73 case TC_ACT_RECLASSIFY:
74 case TC_ACT_OK:
75 case TC_ACT_REDIRECT:
76 action = filter_res;
77 break;
78 case TC_ACT_SHOT:
79 action = filter_res;
80 qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats));
81 break;
82 case TC_ACT_UNSPEC:
83 action = prog->tcf_action;
84 break;
85 default:
86 action = TC_ACT_UNSPEC;
87 break;
88 }
89
90 return action;
91}
92
93static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog)
94{
95 return !prog->bpf_ops;
96}
97
98static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog,
99 struct sk_buff *skb)
100{
101 struct nlattr *nla;
102
103 if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops))
104 return -EMSGSIZE;
105
106 nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops *
107 sizeof(struct sock_filter));
108 if (nla == NULL)
109 return -EMSGSIZE;
110
111 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
112
113 return 0;
114}
115
116static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog,
117 struct sk_buff *skb)
118{
119 struct nlattr *nla;
120
121 if (prog->bpf_name &&
122 nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name))
123 return -EMSGSIZE;
124
125 if (nla_put_u32(skb, TCA_ACT_BPF_ID, prog->filter->aux->id))
126 return -EMSGSIZE;
127
128 nla = nla_reserve(skb, TCA_ACT_BPF_TAG, sizeof(prog->filter->tag));
129 if (nla == NULL)
130 return -EMSGSIZE;
131
132 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
133
134 return 0;
135}
136
137static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
138 int bind, int ref)
139{
140 unsigned char *tp = skb_tail_pointer(skb);
141 struct tcf_bpf *prog = to_bpf(act);
142 struct tc_act_bpf opt = {
143 .index = prog->tcf_index,
144 .refcnt = refcount_read(&prog->tcf_refcnt) - ref,
145 .bindcnt = atomic_read(&prog->tcf_bindcnt) - bind,
146 };
147 struct tcf_t tm;
148 int ret;
149
150 spin_lock_bh(&prog->tcf_lock);
151 opt.action = prog->tcf_action;
152 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
153 goto nla_put_failure;
154
155 if (tcf_bpf_is_ebpf(prog))
156 ret = tcf_bpf_dump_ebpf_info(prog, skb);
157 else
158 ret = tcf_bpf_dump_bpf_info(prog, skb);
159 if (ret)
160 goto nla_put_failure;
161
162 tcf_tm_dump(&tm, &prog->tcf_tm);
163 if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm,
164 TCA_ACT_BPF_PAD))
165 goto nla_put_failure;
166
167 spin_unlock_bh(&prog->tcf_lock);
168 return skb->len;
169
170nla_put_failure:
171 spin_unlock_bh(&prog->tcf_lock);
172 nlmsg_trim(skb, tp);
173 return -1;
174}
175
176static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
177 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
178 [TCA_ACT_BPF_FD] = { .type = NLA_U32 },
179 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING,
180 .len = ACT_BPF_NAME_LEN },
181 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
182 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
183 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
184};
185
186static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
187{
188 struct sock_filter *bpf_ops;
189 struct sock_fprog_kern fprog_tmp;
190 struct bpf_prog *fp;
191 u16 bpf_size, bpf_num_ops;
192 int ret;
193
194 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
195 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
196 return -EINVAL;
197
198 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
199 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
200 return -EINVAL;
201
202 bpf_ops = kmemdup(nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size, GFP_KERNEL);
203 if (bpf_ops == NULL)
204 return -ENOMEM;
205
206 fprog_tmp.len = bpf_num_ops;
207 fprog_tmp.filter = bpf_ops;
208
209 ret = bpf_prog_create(&fp, &fprog_tmp);
210 if (ret < 0) {
211 kfree(bpf_ops);
212 return ret;
213 }
214
215 cfg->bpf_ops = bpf_ops;
216 cfg->bpf_num_ops = bpf_num_ops;
217 cfg->filter = fp;
218 cfg->is_ebpf = false;
219
220 return 0;
221}
222
223static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
224{
225 struct bpf_prog *fp;
226 char *name = NULL;
227 u32 bpf_fd;
228
229 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]);
230
231 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT);
232 if (IS_ERR(fp))
233 return PTR_ERR(fp);
234
235 if (tb[TCA_ACT_BPF_NAME]) {
236 name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL);
237 if (!name) {
238 bpf_prog_put(fp);
239 return -ENOMEM;
240 }
241 }
242
243 cfg->bpf_name = name;
244 cfg->filter = fp;
245 cfg->is_ebpf = true;
246
247 return 0;
248}
249
250static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg)
251{
252 struct bpf_prog *filter = cfg->filter;
253
254 if (filter) {
255 if (cfg->is_ebpf)
256 bpf_prog_put(filter);
257 else
258 bpf_prog_destroy(filter);
259 }
260
261 kfree(cfg->bpf_ops);
262 kfree(cfg->bpf_name);
263}
264
265static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
266 struct tcf_bpf_cfg *cfg)
267{
268 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
269
270
271
272 cfg->filter = rcu_dereference_protected(prog->filter, 1);
273
274 cfg->bpf_ops = prog->bpf_ops;
275 cfg->bpf_name = prog->bpf_name;
276}
277
278static int tcf_bpf_init(struct net *net, struct nlattr *nla,
279 struct nlattr *est, struct tc_action **act,
280 int replace, int bind, bool rtnl_held,
281 struct tcf_proto *tp, u32 flags,
282 struct netlink_ext_ack *extack)
283{
284 struct tc_action_net *tn = net_generic(net, bpf_net_id);
285 struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
286 struct tcf_chain *goto_ch = NULL;
287 struct tcf_bpf_cfg cfg, old;
288 struct tc_act_bpf *parm;
289 struct tcf_bpf *prog;
290 bool is_bpf, is_ebpf;
291 int ret, res = 0;
292 u32 index;
293
294 if (!nla)
295 return -EINVAL;
296
297 ret = nla_parse_nested_deprecated(tb, TCA_ACT_BPF_MAX, nla,
298 act_bpf_policy, NULL);
299 if (ret < 0)
300 return ret;
301
302 if (!tb[TCA_ACT_BPF_PARMS])
303 return -EINVAL;
304
305 parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
306 index = parm->index;
307 ret = tcf_idr_check_alloc(tn, &index, act, bind);
308 if (!ret) {
309 ret = tcf_idr_create(tn, index, est, act,
310 &act_bpf_ops, bind, true, 0);
311 if (ret < 0) {
312 tcf_idr_cleanup(tn, index);
313 return ret;
314 }
315
316 res = ACT_P_CREATED;
317 } else if (ret > 0) {
318
319 if (bind)
320 return 0;
321
322 if (!replace) {
323 tcf_idr_release(*act, bind);
324 return -EEXIST;
325 }
326 } else {
327 return ret;
328 }
329
330 ret = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
331 if (ret < 0)
332 goto release_idr;
333
334 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
335 is_ebpf = tb[TCA_ACT_BPF_FD];
336
337 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
338 ret = -EINVAL;
339 goto put_chain;
340 }
341
342 memset(&cfg, 0, sizeof(cfg));
343
344 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
345 tcf_bpf_init_from_efd(tb, &cfg);
346 if (ret < 0)
347 goto put_chain;
348
349 prog = to_bpf(*act);
350
351 spin_lock_bh(&prog->tcf_lock);
352 if (res != ACT_P_CREATED)
353 tcf_bpf_prog_fill_cfg(prog, &old);
354
355 prog->bpf_ops = cfg.bpf_ops;
356 prog->bpf_name = cfg.bpf_name;
357
358 if (cfg.bpf_num_ops)
359 prog->bpf_num_ops = cfg.bpf_num_ops;
360
361 goto_ch = tcf_action_set_ctrlact(*act, parm->action, goto_ch);
362 rcu_assign_pointer(prog->filter, cfg.filter);
363 spin_unlock_bh(&prog->tcf_lock);
364
365 if (goto_ch)
366 tcf_chain_put_by_act(goto_ch);
367
368 if (res == ACT_P_CREATED) {
369 tcf_idr_insert(tn, *act);
370 } else {
371
372 synchronize_rcu();
373 tcf_bpf_cfg_cleanup(&old);
374 }
375
376 return res;
377
378put_chain:
379 if (goto_ch)
380 tcf_chain_put_by_act(goto_ch);
381
382release_idr:
383 tcf_idr_release(*act, bind);
384 return ret;
385}
386
387static void tcf_bpf_cleanup(struct tc_action *act)
388{
389 struct tcf_bpf_cfg tmp;
390
391 tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp);
392 tcf_bpf_cfg_cleanup(&tmp);
393}
394
395static int tcf_bpf_walker(struct net *net, struct sk_buff *skb,
396 struct netlink_callback *cb, int type,
397 const struct tc_action_ops *ops,
398 struct netlink_ext_ack *extack)
399{
400 struct tc_action_net *tn = net_generic(net, bpf_net_id);
401
402 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
403}
404
405static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index)
406{
407 struct tc_action_net *tn = net_generic(net, bpf_net_id);
408
409 return tcf_idr_search(tn, a, index);
410}
411
412static struct tc_action_ops act_bpf_ops __read_mostly = {
413 .kind = "bpf",
414 .id = TCA_ID_BPF,
415 .owner = THIS_MODULE,
416 .act = tcf_bpf_act,
417 .dump = tcf_bpf_dump,
418 .cleanup = tcf_bpf_cleanup,
419 .init = tcf_bpf_init,
420 .walk = tcf_bpf_walker,
421 .lookup = tcf_bpf_search,
422 .size = sizeof(struct tcf_bpf),
423};
424
425static __net_init int bpf_init_net(struct net *net)
426{
427 struct tc_action_net *tn = net_generic(net, bpf_net_id);
428
429 return tc_action_net_init(net, tn, &act_bpf_ops);
430}
431
432static void __net_exit bpf_exit_net(struct list_head *net_list)
433{
434 tc_action_net_exit(net_list, bpf_net_id);
435}
436
437static struct pernet_operations bpf_net_ops = {
438 .init = bpf_init_net,
439 .exit_batch = bpf_exit_net,
440 .id = &bpf_net_id,
441 .size = sizeof(struct tc_action_net),
442};
443
444static int __init bpf_init_module(void)
445{
446 return tcf_register_action(&act_bpf_ops, &bpf_net_ops);
447}
448
449static void __exit bpf_cleanup_module(void)
450{
451 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops);
452}
453
454module_init(bpf_init_module);
455module_exit(bpf_cleanup_module);
456
457MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
458MODULE_DESCRIPTION("TC BPF based action");
459MODULE_LICENSE("GPL v2");
460
