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10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/skbuff.h>
14#include <linux/rtnetlink.h>
15#include <linux/filter.h>
16#include <linux/bpf.h>
17
18#include <net/netlink.h>
19#include <net/pkt_sched.h>
20
21#include <linux/tc_act/tc_bpf.h>
22#include <net/tc_act/tc_bpf.h>
23
24#define ACT_BPF_NAME_LEN 256
25
26struct tcf_bpf_cfg {
27 struct bpf_prog *filter;
28 struct sock_filter *bpf_ops;
29 const char *bpf_name;
30 u16 bpf_num_ops;
31 bool is_ebpf;
32};
33
34static unsigned int bpf_net_id;
35static struct tc_action_ops act_bpf_ops;
36
37static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
38 struct tcf_result *res)
39{
40 bool at_ingress = skb_at_tc_ingress(skb);
41 struct tcf_bpf *prog = to_bpf(act);
42 struct bpf_prog *filter;
43 int action, filter_res;
44
45 tcf_lastuse_update(&prog->tcf_tm);
46 bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
47
48 rcu_read_lock();
49 filter = rcu_dereference(prog->filter);
50 if (at_ingress) {
51 __skb_push(skb, skb->mac_len);
52 bpf_compute_data_pointers(skb);
53 filter_res = BPF_PROG_RUN(filter, skb);
54 __skb_pull(skb, skb->mac_len);
55 } else {
56 bpf_compute_data_pointers(skb);
57 filter_res = BPF_PROG_RUN(filter, skb);
58 }
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 = prog->tcf_refcnt - ref,
145 .bindcnt = prog->tcf_bindcnt - bind,
146 .action = prog->tcf_action,
147 };
148 struct tcf_t tm;
149 int ret;
150
151 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
152 goto nla_put_failure;
153
154 if (tcf_bpf_is_ebpf(prog))
155 ret = tcf_bpf_dump_ebpf_info(prog, skb);
156 else
157 ret = tcf_bpf_dump_bpf_info(prog, skb);
158 if (ret)
159 goto nla_put_failure;
160
161 tcf_tm_dump(&tm, &prog->tcf_tm);
162 if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm,
163 TCA_ACT_BPF_PAD))
164 goto nla_put_failure;
165
166 return skb->len;
167
168nla_put_failure:
169 nlmsg_trim(skb, tp);
170 return -1;
171}
172
173static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
174 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
175 [TCA_ACT_BPF_FD] = { .type = NLA_U32 },
176 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING,
177 .len = ACT_BPF_NAME_LEN },
178 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
179 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
180 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
181};
182
183static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
184{
185 struct sock_filter *bpf_ops;
186 struct sock_fprog_kern fprog_tmp;
187 struct bpf_prog *fp;
188 u16 bpf_size, bpf_num_ops;
189 int ret;
190
191 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
192 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
193 return -EINVAL;
194
195 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
196 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
197 return -EINVAL;
198
199 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
200 if (bpf_ops == NULL)
201 return -ENOMEM;
202
203 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
204
205 fprog_tmp.len = bpf_num_ops;
206 fprog_tmp.filter = bpf_ops;
207
208 ret = bpf_prog_create(&fp, &fprog_tmp);
209 if (ret < 0) {
210 kfree(bpf_ops);
211 return ret;
212 }
213
214 cfg->bpf_ops = bpf_ops;
215 cfg->bpf_num_ops = bpf_num_ops;
216 cfg->filter = fp;
217 cfg->is_ebpf = false;
218
219 return 0;
220}
221
222static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
223{
224 struct bpf_prog *fp;
225 char *name = NULL;
226 u32 bpf_fd;
227
228 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]);
229
230 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT);
231 if (IS_ERR(fp))
232 return PTR_ERR(fp);
233
234 if (tb[TCA_ACT_BPF_NAME]) {
235 name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL);
236 if (!name) {
237 bpf_prog_put(fp);
238 return -ENOMEM;
239 }
240 }
241
242 cfg->bpf_name = name;
243 cfg->filter = fp;
244 cfg->is_ebpf = true;
245
246 return 0;
247}
248
249static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg)
250{
251 struct bpf_prog *filter = cfg->filter;
252
253 if (filter) {
254 if (cfg->is_ebpf)
255 bpf_prog_put(filter);
256 else
257 bpf_prog_destroy(filter);
258 }
259
260 kfree(cfg->bpf_ops);
261 kfree(cfg->bpf_name);
262}
263
264static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
265 struct tcf_bpf_cfg *cfg)
266{
267 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
268
269
270
271 cfg->filter = rcu_dereference_protected(prog->filter, 1);
272
273 cfg->bpf_ops = prog->bpf_ops;
274 cfg->bpf_name = prog->bpf_name;
275}
276
277static int tcf_bpf_init(struct net *net, struct nlattr *nla,
278 struct nlattr *est, struct tc_action **act,
279 int replace, int bind, struct netlink_ext_ack *extack)
280{
281 struct tc_action_net *tn = net_generic(net, bpf_net_id);
282 struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
283 struct tcf_bpf_cfg cfg, old;
284 struct tc_act_bpf *parm;
285 struct tcf_bpf *prog;
286 bool is_bpf, is_ebpf;
287 int ret, res = 0;
288
289 if (!nla)
290 return -EINVAL;
291
292 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy, NULL);
293 if (ret < 0)
294 return ret;
295
296 if (!tb[TCA_ACT_BPF_PARMS])
297 return -EINVAL;
298
299 parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
300
301 if (!tcf_idr_check(tn, parm->index, act, bind)) {
302 ret = tcf_idr_create(tn, parm->index, est, act,
303 &act_bpf_ops, bind, true);
304 if (ret < 0)
305 return ret;
306
307 res = ACT_P_CREATED;
308 } else {
309
310 if (bind)
311 return 0;
312
313 tcf_idr_release(*act, bind);
314 if (!replace)
315 return -EEXIST;
316 }
317
318 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
319 is_ebpf = tb[TCA_ACT_BPF_FD];
320
321 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
322 ret = -EINVAL;
323 goto out;
324 }
325
326 memset(&cfg, 0, sizeof(cfg));
327
328 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
329 tcf_bpf_init_from_efd(tb, &cfg);
330 if (ret < 0)
331 goto out;
332
333 prog = to_bpf(*act);
334 ASSERT_RTNL();
335
336 if (res != ACT_P_CREATED)
337 tcf_bpf_prog_fill_cfg(prog, &old);
338
339 prog->bpf_ops = cfg.bpf_ops;
340 prog->bpf_name = cfg.bpf_name;
341
342 if (cfg.bpf_num_ops)
343 prog->bpf_num_ops = cfg.bpf_num_ops;
344
345 prog->tcf_action = parm->action;
346 rcu_assign_pointer(prog->filter, cfg.filter);
347
348 if (res == ACT_P_CREATED) {
349 tcf_idr_insert(tn, *act);
350 } else {
351
352 synchronize_rcu();
353 tcf_bpf_cfg_cleanup(&old);
354 }
355
356 return res;
357out:
358 if (res == ACT_P_CREATED)
359 tcf_idr_release(*act, bind);
360
361 return ret;
362}
363
364static void tcf_bpf_cleanup(struct tc_action *act)
365{
366 struct tcf_bpf_cfg tmp;
367
368 tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp);
369 tcf_bpf_cfg_cleanup(&tmp);
370}
371
372static int tcf_bpf_walker(struct net *net, struct sk_buff *skb,
373 struct netlink_callback *cb, int type,
374 const struct tc_action_ops *ops,
375 struct netlink_ext_ack *extack)
376{
377 struct tc_action_net *tn = net_generic(net, bpf_net_id);
378
379 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
380}
381
382static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index,
383 struct netlink_ext_ack *extack)
384{
385 struct tc_action_net *tn = net_generic(net, bpf_net_id);
386
387 return tcf_idr_search(tn, a, index);
388}
389
390static struct tc_action_ops act_bpf_ops __read_mostly = {
391 .kind = "bpf",
392 .type = TCA_ACT_BPF,
393 .owner = THIS_MODULE,
394 .act = tcf_bpf,
395 .dump = tcf_bpf_dump,
396 .cleanup = tcf_bpf_cleanup,
397 .init = tcf_bpf_init,
398 .walk = tcf_bpf_walker,
399 .lookup = tcf_bpf_search,
400 .size = sizeof(struct tcf_bpf),
401};
402
403static __net_init int bpf_init_net(struct net *net)
404{
405 struct tc_action_net *tn = net_generic(net, bpf_net_id);
406
407 return tc_action_net_init(tn, &act_bpf_ops);
408}
409
410static void __net_exit bpf_exit_net(struct list_head *net_list)
411{
412 tc_action_net_exit(net_list, bpf_net_id);
413}
414
415static struct pernet_operations bpf_net_ops = {
416 .init = bpf_init_net,
417 .exit_batch = bpf_exit_net,
418 .id = &bpf_net_id,
419 .size = sizeof(struct tc_action_net),
420};
421
422static int __init bpf_init_module(void)
423{
424 return tcf_register_action(&act_bpf_ops, &bpf_net_ops);
425}
426
427static void __exit bpf_cleanup_module(void)
428{
429 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops);
430}
431
432module_init(bpf_init_module);
433module_exit(bpf_cleanup_module);
434
435MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
436MODULE_DESCRIPTION("TC BPF based action");
437MODULE_LICENSE("GPL v2");
438
