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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_end(skb);
53 filter_res = BPF_PROG_RUN(filter, skb);
54 __skb_pull(skb, skb->mac_len);
55 } else {
56 bpf_compute_data_end(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 if (cfg->is_ebpf)
252 bpf_prog_put(cfg->filter);
253 else
254 bpf_prog_destroy(cfg->filter);
255
256 kfree(cfg->bpf_ops);
257 kfree(cfg->bpf_name);
258}
259
260static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
261 struct tcf_bpf_cfg *cfg)
262{
263 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
264
265
266
267 cfg->filter = rcu_dereference_protected(prog->filter, 1);
268
269 cfg->bpf_ops = prog->bpf_ops;
270 cfg->bpf_name = prog->bpf_name;
271}
272
273static int tcf_bpf_init(struct net *net, struct nlattr *nla,
274 struct nlattr *est, struct tc_action **act,
275 int replace, int bind)
276{
277 struct tc_action_net *tn = net_generic(net, bpf_net_id);
278 struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
279 struct tcf_bpf_cfg cfg, old;
280 struct tc_act_bpf *parm;
281 struct tcf_bpf *prog;
282 bool is_bpf, is_ebpf;
283 int ret, res = 0;
284
285 if (!nla)
286 return -EINVAL;
287
288 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy, NULL);
289 if (ret < 0)
290 return ret;
291
292 if (!tb[TCA_ACT_BPF_PARMS])
293 return -EINVAL;
294
295 parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
296
297 if (!tcf_idr_check(tn, parm->index, act, bind)) {
298 ret = tcf_idr_create(tn, parm->index, est, act,
299 &act_bpf_ops, bind, true);
300 if (ret < 0)
301 return ret;
302
303 res = ACT_P_CREATED;
304 } else {
305
306 if (bind)
307 return 0;
308
309 tcf_idr_release(*act, bind);
310 if (!replace)
311 return -EEXIST;
312 }
313
314 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
315 is_ebpf = tb[TCA_ACT_BPF_FD];
316
317 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
318 ret = -EINVAL;
319 goto out;
320 }
321
322 memset(&cfg, 0, sizeof(cfg));
323
324 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
325 tcf_bpf_init_from_efd(tb, &cfg);
326 if (ret < 0)
327 goto out;
328
329 prog = to_bpf(*act);
330 ASSERT_RTNL();
331
332 if (res != ACT_P_CREATED)
333 tcf_bpf_prog_fill_cfg(prog, &old);
334
335 prog->bpf_ops = cfg.bpf_ops;
336 prog->bpf_name = cfg.bpf_name;
337
338 if (cfg.bpf_num_ops)
339 prog->bpf_num_ops = cfg.bpf_num_ops;
340
341 prog->tcf_action = parm->action;
342 rcu_assign_pointer(prog->filter, cfg.filter);
343
344 if (res == ACT_P_CREATED) {
345 tcf_idr_insert(tn, *act);
346 } else {
347
348 synchronize_rcu();
349 tcf_bpf_cfg_cleanup(&old);
350 }
351
352 return res;
353out:
354 if (res == ACT_P_CREATED)
355 tcf_idr_cleanup(*act, est);
356
357 return ret;
358}
359
360static void tcf_bpf_cleanup(struct tc_action *act, int bind)
361{
362 struct tcf_bpf_cfg tmp;
363
364 tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp);
365 tcf_bpf_cfg_cleanup(&tmp);
366}
367
368static int tcf_bpf_walker(struct net *net, struct sk_buff *skb,
369 struct netlink_callback *cb, int type,
370 const struct tc_action_ops *ops)
371{
372 struct tc_action_net *tn = net_generic(net, bpf_net_id);
373
374 return tcf_generic_walker(tn, skb, cb, type, ops);
375}
376
377static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index)
378{
379 struct tc_action_net *tn = net_generic(net, bpf_net_id);
380
381 return tcf_idr_search(tn, a, index);
382}
383
384static struct tc_action_ops act_bpf_ops __read_mostly = {
385 .kind = "bpf",
386 .type = TCA_ACT_BPF,
387 .owner = THIS_MODULE,
388 .act = tcf_bpf,
389 .dump = tcf_bpf_dump,
390 .cleanup = tcf_bpf_cleanup,
391 .init = tcf_bpf_init,
392 .walk = tcf_bpf_walker,
393 .lookup = tcf_bpf_search,
394 .size = sizeof(struct tcf_bpf),
395};
396
397static __net_init int bpf_init_net(struct net *net)
398{
399 struct tc_action_net *tn = net_generic(net, bpf_net_id);
400
401 return tc_action_net_init(tn, &act_bpf_ops);
402}
403
404static void __net_exit bpf_exit_net(struct net *net)
405{
406 struct tc_action_net *tn = net_generic(net, bpf_net_id);
407
408 tc_action_net_exit(tn);
409}
410
411static struct pernet_operations bpf_net_ops = {
412 .init = bpf_init_net,
413 .exit = bpf_exit_net,
414 .id = &bpf_net_id,
415 .size = sizeof(struct tc_action_net),
416};
417
418static int __init bpf_init_module(void)
419{
420 return tcf_register_action(&act_bpf_ops, &bpf_net_ops);
421}
422
423static void __exit bpf_cleanup_module(void)
424{
425 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops);
426}
427
428module_init(bpf_init_module);
429module_exit(bpf_cleanup_module);
430
431MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
432MODULE_DESCRIPTION("TC BPF based action");
433MODULE_LICENSE("GPL v2");
434
