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Commit | Line | Data |
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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 | 31 | u16 bpf_num_ops; |
f4eaed28 | 32 | bool is_ebpf; |
a8cb5f55 | 33 | }; |
d23b8ad8 | 34 | |
c7d03a00 | 35 | static unsigned int bpf_net_id; |
a85a970a | 36 | static struct tc_action_ops act_bpf_ops; |
ddf97ccd | 37 | |
a8cb5f55 | 38 | static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act, |
d23b8ad8 JP |
39 | struct tcf_result *res) |
40 | { | |
f53d8c7b | 41 | bool at_ingress = skb_at_tc_ingress(skb); |
a85a970a | 42 | struct tcf_bpf *prog = to_bpf(act); |
cff82457 | 43 | struct bpf_prog *filter; |
ced585c8 | 44 | int action, filter_res; |
d23b8ad8 | 45 | |
cff82457 AS |
46 | tcf_lastuse_update(&prog->tcf_tm); |
47 | bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb); | |
d23b8ad8 | 48 | |
a8cb5f55 | 49 | rcu_read_lock(); |
cff82457 | 50 | filter = rcu_dereference(prog->filter); |
3431205e AS |
51 | if (at_ingress) { |
52 | __skb_push(skb, skb->mac_len); | |
db58ba45 | 53 | bpf_compute_data_end(skb); |
cff82457 | 54 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e AS |
55 | __skb_pull(skb, skb->mac_len); |
56 | } else { | |
db58ba45 | 57 | bpf_compute_data_end(skb); |
cff82457 | 58 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e | 59 | } |
a8cb5f55 | 60 | rcu_read_unlock(); |
ced585c8 DB |
61 | |
62 | /* A BPF program may overwrite the default action opcode. | |
63 | * Similarly as in cls_bpf, if filter_res == -1 we use the | |
64 | * default action specified from tc. | |
65 | * | |
66 | * In case a different well-known TC_ACT opcode has been | |
67 | * returned, it will overwrite the default one. | |
68 | * | |
69 | * For everything else that is unkown, TC_ACT_UNSPEC is | |
70 | * returned. | |
71 | */ | |
72 | switch (filter_res) { | |
73 | case TC_ACT_PIPE: | |
74 | case TC_ACT_RECLASSIFY: | |
75 | case TC_ACT_OK: | |
27b29f63 | 76 | case TC_ACT_REDIRECT: |
ced585c8 DB |
77 | action = filter_res; |
78 | break; | |
79 | case TC_ACT_SHOT: | |
80 | action = filter_res; | |
cff82457 | 81 | qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats)); |
ced585c8 DB |
82 | break; |
83 | case TC_ACT_UNSPEC: | |
a8cb5f55 | 84 | action = prog->tcf_action; |
ced585c8 DB |
85 | break; |
86 | default: | |
87 | action = TC_ACT_UNSPEC; | |
88 | break; | |
d23b8ad8 JP |
89 | } |
90 | ||
d23b8ad8 JP |
91 | return action; |
92 | } | |
93 | ||
a8cb5f55 DB |
94 | static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) |
95 | { | |
96 | return !prog->bpf_ops; | |
97 | } | |
98 | ||
99 | static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, | |
100 | struct sk_buff *skb) | |
101 | { | |
102 | struct nlattr *nla; | |
103 | ||
104 | if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) | |
105 | return -EMSGSIZE; | |
106 | ||
107 | nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * | |
108 | sizeof(struct sock_filter)); | |
109 | if (nla == NULL) | |
110 | return -EMSGSIZE; | |
111 | ||
112 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, | |
118 | struct sk_buff *skb) | |
119 | { | |
7bd509e3 DB |
120 | struct nlattr *nla; |
121 | ||
a8cb5f55 DB |
122 | if (prog->bpf_name && |
123 | nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) | |
124 | return -EMSGSIZE; | |
125 | ||
f1f7714e | 126 | nla = nla_reserve(skb, TCA_ACT_BPF_TAG, sizeof(prog->filter->tag)); |
7bd509e3 DB |
127 | if (nla == NULL) |
128 | return -EMSGSIZE; | |
129 | ||
f1f7714e | 130 | memcpy(nla_data(nla), prog->filter->tag, nla_len(nla)); |
7bd509e3 | 131 | |
a8cb5f55 DB |
132 | return 0; |
133 | } | |
134 | ||
135 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, | |
d23b8ad8 JP |
136 | int bind, int ref) |
137 | { | |
138 | unsigned char *tp = skb_tail_pointer(skb); | |
a85a970a | 139 | struct tcf_bpf *prog = to_bpf(act); |
d23b8ad8 | 140 | struct tc_act_bpf opt = { |
a8cb5f55 DB |
141 | .index = prog->tcf_index, |
142 | .refcnt = prog->tcf_refcnt - ref, | |
143 | .bindcnt = prog->tcf_bindcnt - bind, | |
144 | .action = prog->tcf_action, | |
d23b8ad8 | 145 | }; |
a8cb5f55 DB |
146 | struct tcf_t tm; |
147 | int ret; | |
d23b8ad8 JP |
148 | |
149 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) | |
150 | goto nla_put_failure; | |
151 | ||
a8cb5f55 DB |
152 | if (tcf_bpf_is_ebpf(prog)) |
153 | ret = tcf_bpf_dump_ebpf_info(prog, skb); | |
154 | else | |
155 | ret = tcf_bpf_dump_bpf_info(prog, skb); | |
156 | if (ret) | |
d23b8ad8 JP |
157 | goto nla_put_failure; |
158 | ||
48d8ee16 | 159 | tcf_tm_dump(&tm, &prog->tcf_tm); |
9854518e ND |
160 | if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm, |
161 | TCA_ACT_BPF_PAD)) | |
d23b8ad8 | 162 | goto nla_put_failure; |
a8cb5f55 | 163 | |
d23b8ad8 JP |
164 | return skb->len; |
165 | ||
166 | nla_put_failure: | |
167 | nlmsg_trim(skb, tp); | |
168 | return -1; | |
169 | } | |
170 | ||
171 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
172 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
a8cb5f55 | 173 | [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, |
0b0f43fe JHS |
174 | [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, |
175 | .len = ACT_BPF_NAME_LEN }, | |
d23b8ad8 JP |
176 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, |
177 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
178 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
179 | }; | |
180 | ||
a8cb5f55 | 181 | static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
d23b8ad8 | 182 | { |
d23b8ad8 | 183 | struct sock_filter *bpf_ops; |
a8cb5f55 | 184 | struct sock_fprog_kern fprog_tmp; |
d23b8ad8 | 185 | struct bpf_prog *fp; |
a8cb5f55 | 186 | u16 bpf_size, bpf_num_ops; |
d23b8ad8 JP |
187 | int ret; |
188 | ||
d23b8ad8 JP |
189 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); |
190 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
191 | return -EINVAL; | |
192 | ||
193 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
fd3e646c DB |
194 | if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
195 | return -EINVAL; | |
196 | ||
d23b8ad8 | 197 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
a8cb5f55 | 198 | if (bpf_ops == NULL) |
d23b8ad8 JP |
199 | return -ENOMEM; |
200 | ||
201 | memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); | |
202 | ||
a8cb5f55 DB |
203 | fprog_tmp.len = bpf_num_ops; |
204 | fprog_tmp.filter = bpf_ops; | |
d23b8ad8 | 205 | |
a8cb5f55 DB |
206 | ret = bpf_prog_create(&fp, &fprog_tmp); |
207 | if (ret < 0) { | |
208 | kfree(bpf_ops); | |
209 | return ret; | |
210 | } | |
d23b8ad8 | 211 | |
a8cb5f55 DB |
212 | cfg->bpf_ops = bpf_ops; |
213 | cfg->bpf_num_ops = bpf_num_ops; | |
214 | cfg->filter = fp; | |
f4eaed28 | 215 | cfg->is_ebpf = false; |
a8cb5f55 DB |
216 | |
217 | return 0; | |
218 | } | |
219 | ||
220 | static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) | |
221 | { | |
222 | struct bpf_prog *fp; | |
223 | char *name = NULL; | |
224 | u32 bpf_fd; | |
225 | ||
226 | bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); | |
227 | ||
113214be | 228 | fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT); |
a8cb5f55 DB |
229 | if (IS_ERR(fp)) |
230 | return PTR_ERR(fp); | |
231 | ||
a8cb5f55 | 232 | if (tb[TCA_ACT_BPF_NAME]) { |
b15ca182 | 233 | name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL); |
a8cb5f55 DB |
234 | if (!name) { |
235 | bpf_prog_put(fp); | |
236 | return -ENOMEM; | |
237 | } | |
238 | } | |
239 | ||
a8cb5f55 DB |
240 | cfg->bpf_name = name; |
241 | cfg->filter = fp; | |
f4eaed28 | 242 | cfg->is_ebpf = true; |
a8cb5f55 DB |
243 | |
244 | return 0; | |
245 | } | |
246 | ||
f4eaed28 DB |
247 | static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) |
248 | { | |
249 | if (cfg->is_ebpf) | |
250 | bpf_prog_put(cfg->filter); | |
251 | else | |
252 | bpf_prog_destroy(cfg->filter); | |
253 | ||
254 | kfree(cfg->bpf_ops); | |
255 | kfree(cfg->bpf_name); | |
256 | } | |
257 | ||
258 | static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, | |
259 | struct tcf_bpf_cfg *cfg) | |
260 | { | |
261 | cfg->is_ebpf = tcf_bpf_is_ebpf(prog); | |
cff82457 AS |
262 | /* updates to prog->filter are prevented, since it's called either |
263 | * with rtnl lock or during final cleanup in rcu callback | |
264 | */ | |
265 | cfg->filter = rcu_dereference_protected(prog->filter, 1); | |
f4eaed28 DB |
266 | |
267 | cfg->bpf_ops = prog->bpf_ops; | |
268 | cfg->bpf_name = prog->bpf_name; | |
269 | } | |
270 | ||
a8cb5f55 | 271 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, |
a85a970a | 272 | struct nlattr *est, struct tc_action **act, |
a8cb5f55 DB |
273 | int replace, int bind) |
274 | { | |
ddf97ccd | 275 | struct tc_action_net *tn = net_generic(net, bpf_net_id); |
a8cb5f55 | 276 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; |
f4eaed28 | 277 | struct tcf_bpf_cfg cfg, old; |
a8cb5f55 DB |
278 | struct tc_act_bpf *parm; |
279 | struct tcf_bpf *prog; | |
a8cb5f55 | 280 | bool is_bpf, is_ebpf; |
a5c90b29 | 281 | int ret, res = 0; |
a8cb5f55 DB |
282 | |
283 | if (!nla) | |
284 | return -EINVAL; | |
285 | ||
fceb6435 | 286 | ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy, NULL); |
a8cb5f55 DB |
287 | if (ret < 0) |
288 | return ret; | |
289 | ||
a5c90b29 | 290 | if (!tb[TCA_ACT_BPF_PARMS]) |
a8cb5f55 DB |
291 | return -EINVAL; |
292 | ||
293 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
294 | ||
ddf97ccd WC |
295 | if (!tcf_hash_check(tn, parm->index, act, bind)) { |
296 | ret = tcf_hash_create(tn, parm->index, est, act, | |
a85a970a | 297 | &act_bpf_ops, bind, true); |
a8cb5f55 | 298 | if (ret < 0) |
a5c90b29 | 299 | return ret; |
d23b8ad8 | 300 | |
a5c90b29 | 301 | res = ACT_P_CREATED; |
d23b8ad8 | 302 | } else { |
a8cb5f55 | 303 | /* Don't override defaults. */ |
d23b8ad8 | 304 | if (bind) |
a5c90b29 | 305 | return 0; |
a8cb5f55 | 306 | |
a85a970a | 307 | tcf_hash_release(*act, bind); |
a5c90b29 DB |
308 | if (!replace) |
309 | return -EEXIST; | |
d23b8ad8 JP |
310 | } |
311 | ||
a5c90b29 DB |
312 | is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; |
313 | is_ebpf = tb[TCA_ACT_BPF_FD]; | |
314 | ||
315 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) { | |
316 | ret = -EINVAL; | |
317 | goto out; | |
318 | } | |
319 | ||
320 | memset(&cfg, 0, sizeof(cfg)); | |
321 | ||
322 | ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : | |
323 | tcf_bpf_init_from_efd(tb, &cfg); | |
324 | if (ret < 0) | |
325 | goto out; | |
326 | ||
a85a970a | 327 | prog = to_bpf(*act); |
cff82457 | 328 | ASSERT_RTNL(); |
a8cb5f55 | 329 | |
faa54be4 | 330 | if (res != ACT_P_CREATED) |
f4eaed28 DB |
331 | tcf_bpf_prog_fill_cfg(prog, &old); |
332 | ||
a8cb5f55 DB |
333 | prog->bpf_ops = cfg.bpf_ops; |
334 | prog->bpf_name = cfg.bpf_name; | |
335 | ||
336 | if (cfg.bpf_num_ops) | |
337 | prog->bpf_num_ops = cfg.bpf_num_ops; | |
a8cb5f55 DB |
338 | |
339 | prog->tcf_action = parm->action; | |
cff82457 | 340 | rcu_assign_pointer(prog->filter, cfg.filter); |
d23b8ad8 | 341 | |
cff82457 | 342 | if (res == ACT_P_CREATED) { |
a85a970a | 343 | tcf_hash_insert(tn, *act); |
cff82457 AS |
344 | } else { |
345 | /* make sure the program being replaced is no longer executing */ | |
346 | synchronize_rcu(); | |
f4eaed28 | 347 | tcf_bpf_cfg_cleanup(&old); |
cff82457 | 348 | } |
a8cb5f55 | 349 | |
a5c90b29 DB |
350 | return res; |
351 | out: | |
352 | if (res == ACT_P_CREATED) | |
a85a970a | 353 | tcf_hash_cleanup(*act, est); |
d23b8ad8 | 354 | |
d23b8ad8 JP |
355 | return ret; |
356 | } | |
357 | ||
a8cb5f55 | 358 | static void tcf_bpf_cleanup(struct tc_action *act, int bind) |
d23b8ad8 | 359 | { |
f4eaed28 | 360 | struct tcf_bpf_cfg tmp; |
ddf06c1e | 361 | |
a85a970a | 362 | tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp); |
f4eaed28 | 363 | tcf_bpf_cfg_cleanup(&tmp); |
d23b8ad8 JP |
364 | } |
365 | ||
ddf97ccd WC |
366 | static int tcf_bpf_walker(struct net *net, struct sk_buff *skb, |
367 | struct netlink_callback *cb, int type, | |
a85a970a | 368 | const struct tc_action_ops *ops) |
ddf97ccd WC |
369 | { |
370 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
371 | ||
a85a970a | 372 | return tcf_generic_walker(tn, skb, cb, type, ops); |
ddf97ccd WC |
373 | } |
374 | ||
a85a970a | 375 | static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index) |
ddf97ccd WC |
376 | { |
377 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
378 | ||
379 | return tcf_hash_search(tn, a, index); | |
380 | } | |
381 | ||
a8cb5f55 DB |
382 | static struct tc_action_ops act_bpf_ops __read_mostly = { |
383 | .kind = "bpf", | |
384 | .type = TCA_ACT_BPF, | |
385 | .owner = THIS_MODULE, | |
386 | .act = tcf_bpf, | |
387 | .dump = tcf_bpf_dump, | |
388 | .cleanup = tcf_bpf_cleanup, | |
389 | .init = tcf_bpf_init, | |
ddf97ccd WC |
390 | .walk = tcf_bpf_walker, |
391 | .lookup = tcf_bpf_search, | |
a85a970a | 392 | .size = sizeof(struct tcf_bpf), |
ddf97ccd WC |
393 | }; |
394 | ||
395 | static __net_init int bpf_init_net(struct net *net) | |
396 | { | |
397 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
398 | ||
399 | return tc_action_net_init(tn, &act_bpf_ops, BPF_TAB_MASK); | |
400 | } | |
401 | ||
402 | static void __net_exit bpf_exit_net(struct net *net) | |
403 | { | |
404 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
405 | ||
406 | tc_action_net_exit(tn); | |
407 | } | |
408 | ||
409 | static struct pernet_operations bpf_net_ops = { | |
410 | .init = bpf_init_net, | |
411 | .exit = bpf_exit_net, | |
412 | .id = &bpf_net_id, | |
413 | .size = sizeof(struct tc_action_net), | |
d23b8ad8 JP |
414 | }; |
415 | ||
416 | static int __init bpf_init_module(void) | |
417 | { | |
ddf97ccd | 418 | return tcf_register_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
419 | } |
420 | ||
421 | static void __exit bpf_cleanup_module(void) | |
422 | { | |
ddf97ccd | 423 | tcf_unregister_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
424 | } |
425 | ||
426 | module_init(bpf_init_module); | |
427 | module_exit(bpf_cleanup_module); | |
428 | ||
429 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
430 | MODULE_DESCRIPTION("TC BPF based action"); | |
431 | MODULE_LICENSE("GPL v2"); |