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d23b8ad8 JP |
1 | /* |
2 | * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
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> | |
a8cb5f55 DB |
16 | #include <linux/bpf.h> |
17 | ||
d23b8ad8 JP |
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 | ||
a8cb5f55 DB |
24 | #define BPF_TAB_MASK 15 |
25 | #define ACT_BPF_NAME_LEN 256 | |
26 | ||
27 | struct tcf_bpf_cfg { | |
28 | struct bpf_prog *filter; | |
29 | struct sock_filter *bpf_ops; | |
f4eaed28 | 30 | const char *bpf_name; |
a8cb5f55 DB |
31 | u32 bpf_fd; |
32 | u16 bpf_num_ops; | |
f4eaed28 | 33 | bool is_ebpf; |
a8cb5f55 | 34 | }; |
d23b8ad8 | 35 | |
ddf97ccd WC |
36 | static int bpf_net_id; |
37 | ||
a8cb5f55 | 38 | static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act, |
d23b8ad8 JP |
39 | struct tcf_result *res) |
40 | { | |
a8cb5f55 | 41 | struct tcf_bpf *prog = act->priv; |
cff82457 | 42 | struct bpf_prog *filter; |
ced585c8 | 43 | int action, filter_res; |
3431205e | 44 | bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS; |
d23b8ad8 | 45 | |
a166151c AS |
46 | if (unlikely(!skb_mac_header_was_set(skb))) |
47 | return TC_ACT_UNSPEC; | |
48 | ||
cff82457 AS |
49 | tcf_lastuse_update(&prog->tcf_tm); |
50 | bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb); | |
d23b8ad8 | 51 | |
a8cb5f55 | 52 | rcu_read_lock(); |
cff82457 | 53 | filter = rcu_dereference(prog->filter); |
3431205e AS |
54 | if (at_ingress) { |
55 | __skb_push(skb, skb->mac_len); | |
db58ba45 | 56 | bpf_compute_data_end(skb); |
cff82457 | 57 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e AS |
58 | __skb_pull(skb, skb->mac_len); |
59 | } else { | |
db58ba45 | 60 | bpf_compute_data_end(skb); |
cff82457 | 61 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e | 62 | } |
a8cb5f55 | 63 | rcu_read_unlock(); |
ced585c8 DB |
64 | |
65 | /* A BPF program may overwrite the default action opcode. | |
66 | * Similarly as in cls_bpf, if filter_res == -1 we use the | |
67 | * default action specified from tc. | |
68 | * | |
69 | * In case a different well-known TC_ACT opcode has been | |
70 | * returned, it will overwrite the default one. | |
71 | * | |
72 | * For everything else that is unkown, TC_ACT_UNSPEC is | |
73 | * returned. | |
74 | */ | |
75 | switch (filter_res) { | |
76 | case TC_ACT_PIPE: | |
77 | case TC_ACT_RECLASSIFY: | |
78 | case TC_ACT_OK: | |
27b29f63 | 79 | case TC_ACT_REDIRECT: |
ced585c8 DB |
80 | action = filter_res; |
81 | break; | |
82 | case TC_ACT_SHOT: | |
83 | action = filter_res; | |
cff82457 | 84 | qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats)); |
ced585c8 DB |
85 | break; |
86 | case TC_ACT_UNSPEC: | |
a8cb5f55 | 87 | action = prog->tcf_action; |
ced585c8 DB |
88 | break; |
89 | default: | |
90 | action = TC_ACT_UNSPEC; | |
91 | break; | |
d23b8ad8 JP |
92 | } |
93 | ||
d23b8ad8 JP |
94 | return action; |
95 | } | |
96 | ||
a8cb5f55 DB |
97 | static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) |
98 | { | |
99 | return !prog->bpf_ops; | |
100 | } | |
101 | ||
102 | static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, | |
103 | struct sk_buff *skb) | |
104 | { | |
105 | struct nlattr *nla; | |
106 | ||
107 | if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) | |
108 | return -EMSGSIZE; | |
109 | ||
110 | nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * | |
111 | sizeof(struct sock_filter)); | |
112 | if (nla == NULL) | |
113 | return -EMSGSIZE; | |
114 | ||
115 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, | |
121 | struct sk_buff *skb) | |
122 | { | |
123 | if (nla_put_u32(skb, TCA_ACT_BPF_FD, prog->bpf_fd)) | |
124 | return -EMSGSIZE; | |
125 | ||
126 | if (prog->bpf_name && | |
127 | nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) | |
128 | return -EMSGSIZE; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, | |
d23b8ad8 JP |
134 | int bind, int ref) |
135 | { | |
136 | unsigned char *tp = skb_tail_pointer(skb); | |
a8cb5f55 | 137 | struct tcf_bpf *prog = act->priv; |
d23b8ad8 | 138 | struct tc_act_bpf opt = { |
a8cb5f55 DB |
139 | .index = prog->tcf_index, |
140 | .refcnt = prog->tcf_refcnt - ref, | |
141 | .bindcnt = prog->tcf_bindcnt - bind, | |
142 | .action = prog->tcf_action, | |
d23b8ad8 | 143 | }; |
a8cb5f55 DB |
144 | struct tcf_t tm; |
145 | int ret; | |
d23b8ad8 JP |
146 | |
147 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) | |
148 | goto nla_put_failure; | |
149 | ||
a8cb5f55 DB |
150 | if (tcf_bpf_is_ebpf(prog)) |
151 | ret = tcf_bpf_dump_ebpf_info(prog, skb); | |
152 | else | |
153 | ret = tcf_bpf_dump_bpf_info(prog, skb); | |
154 | if (ret) | |
d23b8ad8 JP |
155 | goto nla_put_failure; |
156 | ||
a8cb5f55 DB |
157 | tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install); |
158 | tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse); | |
53eb440f | 159 | tm.firstuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.firstuse); |
a8cb5f55 | 160 | tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires); |
d23b8ad8 | 161 | |
9854518e ND |
162 | if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm, |
163 | TCA_ACT_BPF_PAD)) | |
d23b8ad8 | 164 | goto nla_put_failure; |
a8cb5f55 | 165 | |
d23b8ad8 JP |
166 | return skb->len; |
167 | ||
168 | nla_put_failure: | |
169 | nlmsg_trim(skb, tp); | |
170 | return -1; | |
171 | } | |
172 | ||
173 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
174 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
a8cb5f55 DB |
175 | [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, |
176 | [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN }, | |
d23b8ad8 JP |
177 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, |
178 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
179 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
180 | }; | |
181 | ||
a8cb5f55 | 182 | static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
d23b8ad8 | 183 | { |
d23b8ad8 | 184 | struct sock_filter *bpf_ops; |
a8cb5f55 | 185 | struct sock_fprog_kern fprog_tmp; |
d23b8ad8 | 186 | struct bpf_prog *fp; |
a8cb5f55 | 187 | u16 bpf_size, bpf_num_ops; |
d23b8ad8 JP |
188 | int ret; |
189 | ||
d23b8ad8 JP |
190 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); |
191 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
192 | return -EINVAL; | |
193 | ||
194 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
fd3e646c DB |
195 | if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
196 | return -EINVAL; | |
197 | ||
d23b8ad8 | 198 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
a8cb5f55 | 199 | if (bpf_ops == NULL) |
d23b8ad8 JP |
200 | return -ENOMEM; |
201 | ||
202 | memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); | |
203 | ||
a8cb5f55 DB |
204 | fprog_tmp.len = bpf_num_ops; |
205 | fprog_tmp.filter = bpf_ops; | |
d23b8ad8 | 206 | |
a8cb5f55 DB |
207 | ret = bpf_prog_create(&fp, &fprog_tmp); |
208 | if (ret < 0) { | |
209 | kfree(bpf_ops); | |
210 | return ret; | |
211 | } | |
d23b8ad8 | 212 | |
a8cb5f55 DB |
213 | cfg->bpf_ops = bpf_ops; |
214 | cfg->bpf_num_ops = bpf_num_ops; | |
215 | cfg->filter = fp; | |
f4eaed28 | 216 | cfg->is_ebpf = false; |
a8cb5f55 DB |
217 | |
218 | return 0; | |
219 | } | |
220 | ||
221 | static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) | |
222 | { | |
223 | struct bpf_prog *fp; | |
224 | char *name = NULL; | |
225 | u32 bpf_fd; | |
226 | ||
227 | bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); | |
228 | ||
229 | fp = bpf_prog_get(bpf_fd); | |
230 | if (IS_ERR(fp)) | |
231 | return PTR_ERR(fp); | |
232 | ||
233 | if (fp->type != BPF_PROG_TYPE_SCHED_ACT) { | |
234 | bpf_prog_put(fp); | |
235 | return -EINVAL; | |
236 | } | |
237 | ||
238 | if (tb[TCA_ACT_BPF_NAME]) { | |
239 | name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]), | |
240 | nla_len(tb[TCA_ACT_BPF_NAME]), | |
241 | GFP_KERNEL); | |
242 | if (!name) { | |
243 | bpf_prog_put(fp); | |
244 | return -ENOMEM; | |
245 | } | |
246 | } | |
247 | ||
248 | cfg->bpf_fd = bpf_fd; | |
249 | cfg->bpf_name = name; | |
250 | cfg->filter = fp; | |
f4eaed28 | 251 | cfg->is_ebpf = true; |
a8cb5f55 DB |
252 | |
253 | return 0; | |
254 | } | |
255 | ||
f4eaed28 DB |
256 | static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) |
257 | { | |
258 | if (cfg->is_ebpf) | |
259 | bpf_prog_put(cfg->filter); | |
260 | else | |
261 | bpf_prog_destroy(cfg->filter); | |
262 | ||
263 | kfree(cfg->bpf_ops); | |
264 | kfree(cfg->bpf_name); | |
265 | } | |
266 | ||
267 | static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, | |
268 | struct tcf_bpf_cfg *cfg) | |
269 | { | |
270 | cfg->is_ebpf = tcf_bpf_is_ebpf(prog); | |
cff82457 AS |
271 | /* updates to prog->filter are prevented, since it's called either |
272 | * with rtnl lock or during final cleanup in rcu callback | |
273 | */ | |
274 | cfg->filter = rcu_dereference_protected(prog->filter, 1); | |
f4eaed28 DB |
275 | |
276 | cfg->bpf_ops = prog->bpf_ops; | |
277 | cfg->bpf_name = prog->bpf_name; | |
278 | } | |
279 | ||
a8cb5f55 DB |
280 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, |
281 | struct nlattr *est, struct tc_action *act, | |
282 | int replace, int bind) | |
283 | { | |
ddf97ccd | 284 | struct tc_action_net *tn = net_generic(net, bpf_net_id); |
a8cb5f55 | 285 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; |
f4eaed28 | 286 | struct tcf_bpf_cfg cfg, old; |
a8cb5f55 DB |
287 | struct tc_act_bpf *parm; |
288 | struct tcf_bpf *prog; | |
a8cb5f55 | 289 | bool is_bpf, is_ebpf; |
a5c90b29 | 290 | int ret, res = 0; |
a8cb5f55 DB |
291 | |
292 | if (!nla) | |
293 | return -EINVAL; | |
294 | ||
295 | ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); | |
296 | if (ret < 0) | |
297 | return ret; | |
298 | ||
a5c90b29 | 299 | if (!tb[TCA_ACT_BPF_PARMS]) |
a8cb5f55 DB |
300 | return -EINVAL; |
301 | ||
302 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
303 | ||
ddf97ccd WC |
304 | if (!tcf_hash_check(tn, parm->index, act, bind)) { |
305 | ret = tcf_hash_create(tn, parm->index, est, act, | |
cff82457 | 306 | sizeof(*prog), bind, true); |
a8cb5f55 | 307 | if (ret < 0) |
a5c90b29 | 308 | return ret; |
d23b8ad8 | 309 | |
a5c90b29 | 310 | res = ACT_P_CREATED; |
d23b8ad8 | 311 | } else { |
a8cb5f55 | 312 | /* Don't override defaults. */ |
d23b8ad8 | 313 | if (bind) |
a5c90b29 | 314 | return 0; |
a8cb5f55 DB |
315 | |
316 | tcf_hash_release(act, bind); | |
a5c90b29 DB |
317 | if (!replace) |
318 | return -EEXIST; | |
d23b8ad8 JP |
319 | } |
320 | ||
a5c90b29 DB |
321 | is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; |
322 | is_ebpf = tb[TCA_ACT_BPF_FD]; | |
323 | ||
324 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) { | |
325 | ret = -EINVAL; | |
326 | goto out; | |
327 | } | |
328 | ||
329 | memset(&cfg, 0, sizeof(cfg)); | |
330 | ||
331 | ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : | |
332 | tcf_bpf_init_from_efd(tb, &cfg); | |
333 | if (ret < 0) | |
334 | goto out; | |
335 | ||
a8cb5f55 | 336 | prog = to_bpf(act); |
cff82457 | 337 | ASSERT_RTNL(); |
a8cb5f55 | 338 | |
faa54be4 | 339 | if (res != ACT_P_CREATED) |
f4eaed28 DB |
340 | tcf_bpf_prog_fill_cfg(prog, &old); |
341 | ||
a8cb5f55 DB |
342 | prog->bpf_ops = cfg.bpf_ops; |
343 | prog->bpf_name = cfg.bpf_name; | |
344 | ||
345 | if (cfg.bpf_num_ops) | |
346 | prog->bpf_num_ops = cfg.bpf_num_ops; | |
347 | if (cfg.bpf_fd) | |
348 | prog->bpf_fd = cfg.bpf_fd; | |
349 | ||
350 | prog->tcf_action = parm->action; | |
cff82457 | 351 | rcu_assign_pointer(prog->filter, cfg.filter); |
d23b8ad8 | 352 | |
cff82457 | 353 | if (res == ACT_P_CREATED) { |
ddf97ccd | 354 | tcf_hash_insert(tn, act); |
cff82457 AS |
355 | } else { |
356 | /* make sure the program being replaced is no longer executing */ | |
357 | synchronize_rcu(); | |
f4eaed28 | 358 | tcf_bpf_cfg_cleanup(&old); |
cff82457 | 359 | } |
a8cb5f55 | 360 | |
a5c90b29 DB |
361 | return res; |
362 | out: | |
363 | if (res == ACT_P_CREATED) | |
364 | tcf_hash_cleanup(act, est); | |
d23b8ad8 | 365 | |
d23b8ad8 JP |
366 | return ret; |
367 | } | |
368 | ||
a8cb5f55 | 369 | static void tcf_bpf_cleanup(struct tc_action *act, int bind) |
d23b8ad8 | 370 | { |
f4eaed28 | 371 | struct tcf_bpf_cfg tmp; |
ddf06c1e | 372 | |
f4eaed28 DB |
373 | tcf_bpf_prog_fill_cfg(act->priv, &tmp); |
374 | tcf_bpf_cfg_cleanup(&tmp); | |
d23b8ad8 JP |
375 | } |
376 | ||
ddf97ccd WC |
377 | static int tcf_bpf_walker(struct net *net, struct sk_buff *skb, |
378 | struct netlink_callback *cb, int type, | |
379 | struct tc_action *a) | |
380 | { | |
381 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
382 | ||
383 | return tcf_generic_walker(tn, skb, cb, type, a); | |
384 | } | |
385 | ||
386 | static int tcf_bpf_search(struct net *net, struct tc_action *a, u32 index) | |
387 | { | |
388 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
389 | ||
390 | return tcf_hash_search(tn, a, index); | |
391 | } | |
392 | ||
a8cb5f55 DB |
393 | static struct tc_action_ops act_bpf_ops __read_mostly = { |
394 | .kind = "bpf", | |
395 | .type = TCA_ACT_BPF, | |
396 | .owner = THIS_MODULE, | |
397 | .act = tcf_bpf, | |
398 | .dump = tcf_bpf_dump, | |
399 | .cleanup = tcf_bpf_cleanup, | |
400 | .init = tcf_bpf_init, | |
ddf97ccd WC |
401 | .walk = tcf_bpf_walker, |
402 | .lookup = tcf_bpf_search, | |
403 | }; | |
404 | ||
405 | static __net_init int bpf_init_net(struct net *net) | |
406 | { | |
407 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
408 | ||
409 | return tc_action_net_init(tn, &act_bpf_ops, BPF_TAB_MASK); | |
410 | } | |
411 | ||
412 | static void __net_exit bpf_exit_net(struct net *net) | |
413 | { | |
414 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
415 | ||
416 | tc_action_net_exit(tn); | |
417 | } | |
418 | ||
419 | static struct pernet_operations bpf_net_ops = { | |
420 | .init = bpf_init_net, | |
421 | .exit = bpf_exit_net, | |
422 | .id = &bpf_net_id, | |
423 | .size = sizeof(struct tc_action_net), | |
d23b8ad8 JP |
424 | }; |
425 | ||
426 | static int __init bpf_init_module(void) | |
427 | { | |
ddf97ccd | 428 | return tcf_register_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
429 | } |
430 | ||
431 | static void __exit bpf_cleanup_module(void) | |
432 | { | |
ddf97ccd | 433 | tcf_unregister_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
434 | } |
435 | ||
436 | module_init(bpf_init_module); | |
437 | module_exit(bpf_cleanup_module); | |
438 | ||
439 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
440 | MODULE_DESCRIPTION("TC BPF based action"); | |
441 | MODULE_LICENSE("GPL v2"); |