1
2
3
4
5
6
7
8
9
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 BPF_TAB_MASK 15
25#define ACT_BPF_NAME_LEN 256
26
27struct tcf_bpf_cfg {
28 struct bpf_prog *filter;
29 struct sock_filter *bpf_ops;
30 const char *bpf_name;
31 u32 bpf_fd;
32 u16 bpf_num_ops;
33 bool is_ebpf;
34};
35
36static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
37 struct tcf_result *res)
38{
39 struct tcf_bpf *prog = act->priv;
40 struct bpf_prog *filter;
41 int action, filter_res;
42 bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
43
44 if (unlikely(!skb_mac_header_was_set(skb)))
45 return TC_ACT_UNSPEC;
46
47 tcf_lastuse_update(&prog->tcf_tm);
48 bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
49
50 rcu_read_lock();
51 filter = rcu_dereference(prog->filter);
52 if (at_ingress) {
53 __skb_push(skb, skb->mac_len);
54 filter_res = BPF_PROG_RUN(filter, skb);
55 __skb_pull(skb, skb->mac_len);
56 } else {
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 if (nla_put_u32(skb, TCA_ACT_BPF_FD, prog->bpf_fd))
120 return -EMSGSIZE;
121
122 if (prog->bpf_name &&
123 nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name))
124 return -EMSGSIZE;
125
126 return 0;
127}
128
129static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
130 int bind, int ref)
131{
132 unsigned char *tp = skb_tail_pointer(skb);
133 struct tcf_bpf *prog = act->priv;
134 struct tc_act_bpf opt = {
135 .index = prog->tcf_index,
136 .refcnt = prog->tcf_refcnt - ref,
137 .bindcnt = prog->tcf_bindcnt - bind,
138 .action = prog->tcf_action,
139 };
140 struct tcf_t tm;
141 int ret;
142
143 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
144 goto nla_put_failure;
145
146 if (tcf_bpf_is_ebpf(prog))
147 ret = tcf_bpf_dump_ebpf_info(prog, skb);
148 else
149 ret = tcf_bpf_dump_bpf_info(prog, skb);
150 if (ret)
151 goto nla_put_failure;
152
153 tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install);
154 tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse);
155 tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires);
156
157 if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm))
158 goto nla_put_failure;
159
160 return skb->len;
161
162nla_put_failure:
163 nlmsg_trim(skb, tp);
164 return -1;
165}
166
167static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
168 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
169 [TCA_ACT_BPF_FD] = { .type = NLA_U32 },
170 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN },
171 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
172 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
173 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
174};
175
176static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
177{
178 struct sock_filter *bpf_ops;
179 struct sock_fprog_kern fprog_tmp;
180 struct bpf_prog *fp;
181 u16 bpf_size, bpf_num_ops;
182 int ret;
183
184 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
185 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
186 return -EINVAL;
187
188 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
189 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
190 return -EINVAL;
191
192 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
193 if (bpf_ops == NULL)
194 return -ENOMEM;
195
196 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
197
198 fprog_tmp.len = bpf_num_ops;
199 fprog_tmp.filter = bpf_ops;
200
201 ret = bpf_prog_create(&fp, &fprog_tmp);
202 if (ret < 0) {
203 kfree(bpf_ops);
204 return ret;
205 }
206
207 cfg->bpf_ops = bpf_ops;
208 cfg->bpf_num_ops = bpf_num_ops;
209 cfg->filter = fp;
210 cfg->is_ebpf = false;
211
212 return 0;
213}
214
215static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
216{
217 struct bpf_prog *fp;
218 char *name = NULL;
219 u32 bpf_fd;
220
221 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]);
222
223 fp = bpf_prog_get(bpf_fd);
224 if (IS_ERR(fp))
225 return PTR_ERR(fp);
226
227 if (fp->type != BPF_PROG_TYPE_SCHED_ACT) {
228 bpf_prog_put(fp);
229 return -EINVAL;
230 }
231
232 if (tb[TCA_ACT_BPF_NAME]) {
233 name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]),
234 nla_len(tb[TCA_ACT_BPF_NAME]),
235 GFP_KERNEL);
236 if (!name) {
237 bpf_prog_put(fp);
238 return -ENOMEM;
239 }
240 }
241
242 cfg->bpf_fd = bpf_fd;
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 if (cfg->is_ebpf)
253 bpf_prog_put(cfg->filter);
254 else
255 bpf_prog_destroy(cfg->filter);
256
257 kfree(cfg->bpf_ops);
258 kfree(cfg->bpf_name);
259}
260
261static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
262 struct tcf_bpf_cfg *cfg)
263{
264 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
265
266
267
268 cfg->filter = rcu_dereference_protected(prog->filter, 1);
269
270 cfg->bpf_ops = prog->bpf_ops;
271 cfg->bpf_name = prog->bpf_name;
272}
273
274static int tcf_bpf_init(struct net *net, struct nlattr *nla,
275 struct nlattr *est, struct tc_action *act,
276 int replace, int bind)
277{
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);
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_hash_check(parm->index, act, bind)) {
298 ret = tcf_hash_create(parm->index, est, act,
299 sizeof(*prog), 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_hash_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 if (cfg.bpf_fd)
341 prog->bpf_fd = cfg.bpf_fd;
342
343 prog->tcf_action = parm->action;
344 rcu_assign_pointer(prog->filter, cfg.filter);
345
346 if (res == ACT_P_CREATED) {
347 tcf_hash_insert(act);
348 } else {
349
350 synchronize_rcu();
351 tcf_bpf_cfg_cleanup(&old);
352 }
353
354 return res;
355out:
356 if (res == ACT_P_CREATED)
357 tcf_hash_cleanup(act, est);
358
359 return ret;
360}
361
362static void tcf_bpf_cleanup(struct tc_action *act, int bind)
363{
364 struct tcf_bpf_cfg tmp;
365
366 tcf_bpf_prog_fill_cfg(act->priv, &tmp);
367 tcf_bpf_cfg_cleanup(&tmp);
368}
369
370static struct tc_action_ops act_bpf_ops __read_mostly = {
371 .kind = "bpf",
372 .type = TCA_ACT_BPF,
373 .owner = THIS_MODULE,
374 .act = tcf_bpf,
375 .dump = tcf_bpf_dump,
376 .cleanup = tcf_bpf_cleanup,
377 .init = tcf_bpf_init,
378};
379
380static int __init bpf_init_module(void)
381{
382 return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK);
383}
384
385static void __exit bpf_cleanup_module(void)
386{
387 tcf_unregister_action(&act_bpf_ops);
388}
389
390module_init(bpf_init_module);
391module_exit(bpf_cleanup_module);
392
393MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
394MODULE_DESCRIPTION("TC BPF based action");
395MODULE_LICENSE("GPL v2");
396
