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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; | |
30 | char *bpf_name; | |
31 | u32 bpf_fd; | |
32 | u16 bpf_num_ops; | |
33 | }; | |
d23b8ad8 | 34 | |
a8cb5f55 | 35 | static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act, |
d23b8ad8 JP |
36 | struct tcf_result *res) |
37 | { | |
a8cb5f55 | 38 | struct tcf_bpf *prog = act->priv; |
ced585c8 | 39 | int action, filter_res; |
d23b8ad8 | 40 | |
a166151c AS |
41 | if (unlikely(!skb_mac_header_was_set(skb))) |
42 | return TC_ACT_UNSPEC; | |
43 | ||
a8cb5f55 | 44 | spin_lock(&prog->tcf_lock); |
ced585c8 | 45 | |
a8cb5f55 DB |
46 | prog->tcf_tm.lastuse = jiffies; |
47 | bstats_update(&prog->tcf_bstats, skb); | |
d23b8ad8 | 48 | |
a8cb5f55 DB |
49 | /* Needed here for accessing maps. */ |
50 | rcu_read_lock(); | |
51 | filter_res = BPF_PROG_RUN(prog->filter, skb); | |
52 | rcu_read_unlock(); | |
ced585c8 DB |
53 | |
54 | /* A BPF program may overwrite the default action opcode. | |
55 | * Similarly as in cls_bpf, if filter_res == -1 we use the | |
56 | * default action specified from tc. | |
57 | * | |
58 | * In case a different well-known TC_ACT opcode has been | |
59 | * returned, it will overwrite the default one. | |
60 | * | |
61 | * For everything else that is unkown, TC_ACT_UNSPEC is | |
62 | * returned. | |
63 | */ | |
64 | switch (filter_res) { | |
65 | case TC_ACT_PIPE: | |
66 | case TC_ACT_RECLASSIFY: | |
67 | case TC_ACT_OK: | |
68 | action = filter_res; | |
69 | break; | |
70 | case TC_ACT_SHOT: | |
71 | action = filter_res; | |
a8cb5f55 | 72 | prog->tcf_qstats.drops++; |
ced585c8 DB |
73 | break; |
74 | case TC_ACT_UNSPEC: | |
a8cb5f55 | 75 | action = prog->tcf_action; |
ced585c8 DB |
76 | break; |
77 | default: | |
78 | action = TC_ACT_UNSPEC; | |
79 | break; | |
d23b8ad8 JP |
80 | } |
81 | ||
a8cb5f55 | 82 | spin_unlock(&prog->tcf_lock); |
d23b8ad8 JP |
83 | return action; |
84 | } | |
85 | ||
a8cb5f55 DB |
86 | static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) |
87 | { | |
88 | return !prog->bpf_ops; | |
89 | } | |
90 | ||
91 | static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, | |
92 | struct sk_buff *skb) | |
93 | { | |
94 | struct nlattr *nla; | |
95 | ||
96 | if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) | |
97 | return -EMSGSIZE; | |
98 | ||
99 | nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * | |
100 | sizeof(struct sock_filter)); | |
101 | if (nla == NULL) | |
102 | return -EMSGSIZE; | |
103 | ||
104 | memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, | |
110 | struct sk_buff *skb) | |
111 | { | |
112 | if (nla_put_u32(skb, TCA_ACT_BPF_FD, prog->bpf_fd)) | |
113 | return -EMSGSIZE; | |
114 | ||
115 | if (prog->bpf_name && | |
116 | nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) | |
117 | return -EMSGSIZE; | |
118 | ||
119 | return 0; | |
120 | } | |
121 | ||
122 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, | |
d23b8ad8 JP |
123 | int bind, int ref) |
124 | { | |
125 | unsigned char *tp = skb_tail_pointer(skb); | |
a8cb5f55 | 126 | struct tcf_bpf *prog = act->priv; |
d23b8ad8 | 127 | struct tc_act_bpf opt = { |
a8cb5f55 DB |
128 | .index = prog->tcf_index, |
129 | .refcnt = prog->tcf_refcnt - ref, | |
130 | .bindcnt = prog->tcf_bindcnt - bind, | |
131 | .action = prog->tcf_action, | |
d23b8ad8 | 132 | }; |
a8cb5f55 DB |
133 | struct tcf_t tm; |
134 | int ret; | |
d23b8ad8 JP |
135 | |
136 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) | |
137 | goto nla_put_failure; | |
138 | ||
a8cb5f55 DB |
139 | if (tcf_bpf_is_ebpf(prog)) |
140 | ret = tcf_bpf_dump_ebpf_info(prog, skb); | |
141 | else | |
142 | ret = tcf_bpf_dump_bpf_info(prog, skb); | |
143 | if (ret) | |
d23b8ad8 JP |
144 | goto nla_put_failure; |
145 | ||
a8cb5f55 DB |
146 | tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install); |
147 | tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse); | |
148 | tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires); | |
d23b8ad8 | 149 | |
a8cb5f55 | 150 | if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm)) |
d23b8ad8 | 151 | goto nla_put_failure; |
a8cb5f55 | 152 | |
d23b8ad8 JP |
153 | return skb->len; |
154 | ||
155 | nla_put_failure: | |
156 | nlmsg_trim(skb, tp); | |
157 | return -1; | |
158 | } | |
159 | ||
160 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
161 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
a8cb5f55 DB |
162 | [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, |
163 | [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN }, | |
d23b8ad8 JP |
164 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, |
165 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
166 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
167 | }; | |
168 | ||
a8cb5f55 | 169 | static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
d23b8ad8 | 170 | { |
d23b8ad8 | 171 | struct sock_filter *bpf_ops; |
a8cb5f55 | 172 | struct sock_fprog_kern fprog_tmp; |
d23b8ad8 | 173 | struct bpf_prog *fp; |
a8cb5f55 | 174 | u16 bpf_size, bpf_num_ops; |
d23b8ad8 JP |
175 | int ret; |
176 | ||
d23b8ad8 JP |
177 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); |
178 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
179 | return -EINVAL; | |
180 | ||
181 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
fd3e646c DB |
182 | if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
183 | return -EINVAL; | |
184 | ||
d23b8ad8 | 185 | bpf_ops = kzalloc(bpf_size, GFP_KERNEL); |
a8cb5f55 | 186 | if (bpf_ops == NULL) |
d23b8ad8 JP |
187 | return -ENOMEM; |
188 | ||
189 | memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); | |
190 | ||
a8cb5f55 DB |
191 | fprog_tmp.len = bpf_num_ops; |
192 | fprog_tmp.filter = bpf_ops; | |
d23b8ad8 | 193 | |
a8cb5f55 DB |
194 | ret = bpf_prog_create(&fp, &fprog_tmp); |
195 | if (ret < 0) { | |
196 | kfree(bpf_ops); | |
197 | return ret; | |
198 | } | |
d23b8ad8 | 199 | |
a8cb5f55 DB |
200 | cfg->bpf_ops = bpf_ops; |
201 | cfg->bpf_num_ops = bpf_num_ops; | |
202 | cfg->filter = fp; | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
207 | static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) | |
208 | { | |
209 | struct bpf_prog *fp; | |
210 | char *name = NULL; | |
211 | u32 bpf_fd; | |
212 | ||
213 | bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); | |
214 | ||
215 | fp = bpf_prog_get(bpf_fd); | |
216 | if (IS_ERR(fp)) | |
217 | return PTR_ERR(fp); | |
218 | ||
219 | if (fp->type != BPF_PROG_TYPE_SCHED_ACT) { | |
220 | bpf_prog_put(fp); | |
221 | return -EINVAL; | |
222 | } | |
223 | ||
224 | if (tb[TCA_ACT_BPF_NAME]) { | |
225 | name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]), | |
226 | nla_len(tb[TCA_ACT_BPF_NAME]), | |
227 | GFP_KERNEL); | |
228 | if (!name) { | |
229 | bpf_prog_put(fp); | |
230 | return -ENOMEM; | |
231 | } | |
232 | } | |
233 | ||
234 | cfg->bpf_fd = bpf_fd; | |
235 | cfg->bpf_name = name; | |
236 | cfg->filter = fp; | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, | |
242 | struct nlattr *est, struct tc_action *act, | |
243 | int replace, int bind) | |
244 | { | |
245 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; | |
246 | struct tc_act_bpf *parm; | |
247 | struct tcf_bpf *prog; | |
248 | struct tcf_bpf_cfg cfg; | |
249 | bool is_bpf, is_ebpf; | |
250 | int ret; | |
251 | ||
252 | if (!nla) | |
253 | return -EINVAL; | |
254 | ||
255 | ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); | |
256 | if (ret < 0) | |
257 | return ret; | |
258 | ||
259 | is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; | |
260 | is_ebpf = tb[TCA_ACT_BPF_FD]; | |
261 | ||
262 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) || | |
263 | !tb[TCA_ACT_BPF_PARMS]) | |
264 | return -EINVAL; | |
265 | ||
266 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
267 | ||
268 | memset(&cfg, 0, sizeof(cfg)); | |
269 | ||
270 | ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : | |
271 | tcf_bpf_init_from_efd(tb, &cfg); | |
272 | if (ret < 0) | |
273 | return ret; | |
274 | ||
275 | if (!tcf_hash_check(parm->index, act, bind)) { | |
276 | ret = tcf_hash_create(parm->index, est, act, | |
277 | sizeof(*prog), bind); | |
278 | if (ret < 0) | |
d23b8ad8 JP |
279 | goto destroy_fp; |
280 | ||
281 | ret = ACT_P_CREATED; | |
282 | } else { | |
a8cb5f55 | 283 | /* Don't override defaults. */ |
d23b8ad8 JP |
284 | if (bind) |
285 | goto destroy_fp; | |
a8cb5f55 DB |
286 | |
287 | tcf_hash_release(act, bind); | |
288 | if (!replace) { | |
d23b8ad8 JP |
289 | ret = -EEXIST; |
290 | goto destroy_fp; | |
291 | } | |
292 | } | |
293 | ||
a8cb5f55 DB |
294 | prog = to_bpf(act); |
295 | spin_lock_bh(&prog->tcf_lock); | |
296 | ||
297 | prog->bpf_ops = cfg.bpf_ops; | |
298 | prog->bpf_name = cfg.bpf_name; | |
299 | ||
300 | if (cfg.bpf_num_ops) | |
301 | prog->bpf_num_ops = cfg.bpf_num_ops; | |
302 | if (cfg.bpf_fd) | |
303 | prog->bpf_fd = cfg.bpf_fd; | |
304 | ||
305 | prog->tcf_action = parm->action; | |
306 | prog->filter = cfg.filter; | |
307 | ||
308 | spin_unlock_bh(&prog->tcf_lock); | |
d23b8ad8 JP |
309 | |
310 | if (ret == ACT_P_CREATED) | |
a8cb5f55 DB |
311 | tcf_hash_insert(act); |
312 | ||
d23b8ad8 JP |
313 | return ret; |
314 | ||
315 | destroy_fp: | |
a8cb5f55 DB |
316 | if (is_ebpf) |
317 | bpf_prog_put(cfg.filter); | |
318 | else | |
319 | bpf_prog_destroy(cfg.filter); | |
320 | ||
321 | kfree(cfg.bpf_ops); | |
322 | kfree(cfg.bpf_name); | |
323 | ||
d23b8ad8 JP |
324 | return ret; |
325 | } | |
326 | ||
a8cb5f55 | 327 | static void tcf_bpf_cleanup(struct tc_action *act, int bind) |
d23b8ad8 | 328 | { |
a8cb5f55 | 329 | const struct tcf_bpf *prog = act->priv; |
d23b8ad8 | 330 | |
a8cb5f55 DB |
331 | if (tcf_bpf_is_ebpf(prog)) |
332 | bpf_prog_put(prog->filter); | |
333 | else | |
334 | bpf_prog_destroy(prog->filter); | |
d23b8ad8 JP |
335 | } |
336 | ||
a8cb5f55 DB |
337 | static struct tc_action_ops act_bpf_ops __read_mostly = { |
338 | .kind = "bpf", | |
339 | .type = TCA_ACT_BPF, | |
340 | .owner = THIS_MODULE, | |
341 | .act = tcf_bpf, | |
342 | .dump = tcf_bpf_dump, | |
343 | .cleanup = tcf_bpf_cleanup, | |
344 | .init = tcf_bpf_init, | |
d23b8ad8 JP |
345 | }; |
346 | ||
347 | static int __init bpf_init_module(void) | |
348 | { | |
349 | return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK); | |
350 | } | |
351 | ||
352 | static void __exit bpf_cleanup_module(void) | |
353 | { | |
354 | tcf_unregister_action(&act_bpf_ops); | |
355 | } | |
356 | ||
357 | module_init(bpf_init_module); | |
358 | module_exit(bpf_cleanup_module); | |
359 | ||
360 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
361 | MODULE_DESCRIPTION("TC BPF based action"); | |
362 | MODULE_LICENSE("GPL v2"); |