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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
d23b8ad8 JP |
2 | /* |
3 | * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> | |
d23b8ad8 JP |
4 | */ |
5 | ||
6 | #include <linux/module.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/kernel.h> | |
9 | #include <linux/skbuff.h> | |
10 | #include <linux/rtnetlink.h> | |
11 | #include <linux/filter.h> | |
a8cb5f55 DB |
12 | #include <linux/bpf.h> |
13 | ||
d23b8ad8 | 14 | #include <net/netlink.h> |
cf7fbe66 | 15 | #include <net/sock.h> |
d23b8ad8 | 16 | #include <net/pkt_sched.h> |
4e181004 | 17 | #include <net/pkt_cls.h> |
d23b8ad8 JP |
18 | |
19 | #include <linux/tc_act/tc_bpf.h> | |
20 | #include <net/tc_act/tc_bpf.h> | |
21 | ||
a8cb5f55 DB |
22 | #define ACT_BPF_NAME_LEN 256 |
23 | ||
24 | struct tcf_bpf_cfg { | |
25 | struct bpf_prog *filter; | |
26 | struct sock_filter *bpf_ops; | |
f4eaed28 | 27 | const char *bpf_name; |
a8cb5f55 | 28 | u16 bpf_num_ops; |
f4eaed28 | 29 | bool is_ebpf; |
a8cb5f55 | 30 | }; |
d23b8ad8 | 31 | |
c7d03a00 | 32 | static unsigned int bpf_net_id; |
a85a970a | 33 | static struct tc_action_ops act_bpf_ops; |
ddf97ccd | 34 | |
2fbec27f JHS |
35 | static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act, |
36 | struct tcf_result *res) | |
d23b8ad8 | 37 | { |
f53d8c7b | 38 | bool at_ingress = skb_at_tc_ingress(skb); |
a85a970a | 39 | struct tcf_bpf *prog = to_bpf(act); |
cff82457 | 40 | struct bpf_prog *filter; |
ced585c8 | 41 | int action, filter_res; |
d23b8ad8 | 42 | |
cff82457 AS |
43 | tcf_lastuse_update(&prog->tcf_tm); |
44 | bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb); | |
d23b8ad8 | 45 | |
a8cb5f55 | 46 | rcu_read_lock(); |
cff82457 | 47 | filter = rcu_dereference(prog->filter); |
3431205e AS |
48 | if (at_ingress) { |
49 | __skb_push(skb, skb->mac_len); | |
6aaae2b6 | 50 | bpf_compute_data_pointers(skb); |
cff82457 | 51 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e AS |
52 | __skb_pull(skb, skb->mac_len); |
53 | } else { | |
6aaae2b6 | 54 | bpf_compute_data_pointers(skb); |
cff82457 | 55 | filter_res = BPF_PROG_RUN(filter, skb); |
3431205e | 56 | } |
cf7fbe66 JS |
57 | if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK) |
58 | skb_orphan(skb); | |
a8cb5f55 | 59 | rcu_read_unlock(); |
ced585c8 DB |
60 | |
61 | /* A BPF program may overwrite the default action opcode. | |
62 | * Similarly as in cls_bpf, if filter_res == -1 we use the | |
63 | * default action specified from tc. | |
64 | * | |
65 | * In case a different well-known TC_ACT opcode has been | |
66 | * returned, it will overwrite the default one. | |
67 | * | |
68 | * For everything else that is unkown, TC_ACT_UNSPEC is | |
69 | * returned. | |
70 | */ | |
71 | switch (filter_res) { | |
72 | case TC_ACT_PIPE: | |
73 | case TC_ACT_RECLASSIFY: | |
74 | case TC_ACT_OK: | |
27b29f63 | 75 | case TC_ACT_REDIRECT: |
ced585c8 DB |
76 | action = filter_res; |
77 | break; | |
78 | case TC_ACT_SHOT: | |
79 | action = filter_res; | |
cff82457 | 80 | qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats)); |
ced585c8 DB |
81 | break; |
82 | case TC_ACT_UNSPEC: | |
a8cb5f55 | 83 | action = prog->tcf_action; |
ced585c8 DB |
84 | break; |
85 | default: | |
86 | action = TC_ACT_UNSPEC; | |
87 | break; | |
d23b8ad8 JP |
88 | } |
89 | ||
d23b8ad8 JP |
90 | return action; |
91 | } | |
92 | ||
a8cb5f55 DB |
93 | static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) |
94 | { | |
95 | return !prog->bpf_ops; | |
96 | } | |
97 | ||
98 | static 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 | ||
116 | static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, | |
117 | struct sk_buff *skb) | |
118 | { | |
7bd509e3 DB |
119 | struct nlattr *nla; |
120 | ||
a8cb5f55 DB |
121 | if (prog->bpf_name && |
122 | nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) | |
123 | return -EMSGSIZE; | |
124 | ||
e8628307 DB |
125 | if (nla_put_u32(skb, TCA_ACT_BPF_ID, prog->filter->aux->id)) |
126 | return -EMSGSIZE; | |
127 | ||
f1f7714e | 128 | nla = nla_reserve(skb, TCA_ACT_BPF_TAG, sizeof(prog->filter->tag)); |
7bd509e3 DB |
129 | if (nla == NULL) |
130 | return -EMSGSIZE; | |
131 | ||
f1f7714e | 132 | memcpy(nla_data(nla), prog->filter->tag, nla_len(nla)); |
7bd509e3 | 133 | |
a8cb5f55 DB |
134 | return 0; |
135 | } | |
136 | ||
137 | static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, | |
d23b8ad8 JP |
138 | int bind, int ref) |
139 | { | |
140 | unsigned char *tp = skb_tail_pointer(skb); | |
a85a970a | 141 | struct tcf_bpf *prog = to_bpf(act); |
d23b8ad8 | 142 | struct tc_act_bpf opt = { |
a8cb5f55 | 143 | .index = prog->tcf_index, |
036bb443 VB |
144 | .refcnt = refcount_read(&prog->tcf_refcnt) - ref, |
145 | .bindcnt = atomic_read(&prog->tcf_bindcnt) - bind, | |
d23b8ad8 | 146 | }; |
a8cb5f55 DB |
147 | struct tcf_t tm; |
148 | int ret; | |
d23b8ad8 | 149 | |
653cd284 | 150 | spin_lock_bh(&prog->tcf_lock); |
2142236b | 151 | opt.action = prog->tcf_action; |
d23b8ad8 JP |
152 | if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) |
153 | goto nla_put_failure; | |
154 | ||
a8cb5f55 DB |
155 | if (tcf_bpf_is_ebpf(prog)) |
156 | ret = tcf_bpf_dump_ebpf_info(prog, skb); | |
157 | else | |
158 | ret = tcf_bpf_dump_bpf_info(prog, skb); | |
159 | if (ret) | |
d23b8ad8 JP |
160 | goto nla_put_failure; |
161 | ||
48d8ee16 | 162 | tcf_tm_dump(&tm, &prog->tcf_tm); |
9854518e ND |
163 | if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm, |
164 | TCA_ACT_BPF_PAD)) | |
d23b8ad8 | 165 | goto nla_put_failure; |
a8cb5f55 | 166 | |
653cd284 | 167 | spin_unlock_bh(&prog->tcf_lock); |
d23b8ad8 JP |
168 | return skb->len; |
169 | ||
170 | nla_put_failure: | |
653cd284 | 171 | spin_unlock_bh(&prog->tcf_lock); |
d23b8ad8 JP |
172 | nlmsg_trim(skb, tp); |
173 | return -1; | |
174 | } | |
175 | ||
176 | static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { | |
177 | [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, | |
a8cb5f55 | 178 | [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, |
0b0f43fe JHS |
179 | [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, |
180 | .len = ACT_BPF_NAME_LEN }, | |
d23b8ad8 JP |
181 | [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, |
182 | [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, | |
183 | .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, | |
184 | }; | |
185 | ||
a8cb5f55 | 186 | static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) |
d23b8ad8 | 187 | { |
d23b8ad8 | 188 | struct sock_filter *bpf_ops; |
a8cb5f55 | 189 | struct sock_fprog_kern fprog_tmp; |
d23b8ad8 | 190 | struct bpf_prog *fp; |
a8cb5f55 | 191 | u16 bpf_size, bpf_num_ops; |
d23b8ad8 JP |
192 | int ret; |
193 | ||
d23b8ad8 JP |
194 | bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); |
195 | if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) | |
196 | return -EINVAL; | |
197 | ||
198 | bpf_size = bpf_num_ops * sizeof(*bpf_ops); | |
fd3e646c DB |
199 | if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) |
200 | return -EINVAL; | |
201 | ||
3f6bcc51 | 202 | bpf_ops = kmemdup(nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size, GFP_KERNEL); |
a8cb5f55 | 203 | if (bpf_ops == NULL) |
d23b8ad8 JP |
204 | return -ENOMEM; |
205 | ||
a8cb5f55 DB |
206 | fprog_tmp.len = bpf_num_ops; |
207 | fprog_tmp.filter = bpf_ops; | |
d23b8ad8 | 208 | |
a8cb5f55 DB |
209 | ret = bpf_prog_create(&fp, &fprog_tmp); |
210 | if (ret < 0) { | |
211 | kfree(bpf_ops); | |
212 | return ret; | |
213 | } | |
d23b8ad8 | 214 | |
a8cb5f55 DB |
215 | cfg->bpf_ops = bpf_ops; |
216 | cfg->bpf_num_ops = bpf_num_ops; | |
217 | cfg->filter = fp; | |
f4eaed28 | 218 | cfg->is_ebpf = false; |
a8cb5f55 DB |
219 | |
220 | return 0; | |
221 | } | |
222 | ||
223 | static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) | |
224 | { | |
225 | struct bpf_prog *fp; | |
226 | char *name = NULL; | |
227 | u32 bpf_fd; | |
228 | ||
229 | bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); | |
230 | ||
113214be | 231 | fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT); |
a8cb5f55 DB |
232 | if (IS_ERR(fp)) |
233 | return PTR_ERR(fp); | |
234 | ||
a8cb5f55 | 235 | if (tb[TCA_ACT_BPF_NAME]) { |
b15ca182 | 236 | name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL); |
a8cb5f55 DB |
237 | if (!name) { |
238 | bpf_prog_put(fp); | |
239 | return -ENOMEM; | |
240 | } | |
241 | } | |
242 | ||
a8cb5f55 DB |
243 | cfg->bpf_name = name; |
244 | cfg->filter = fp; | |
f4eaed28 | 245 | cfg->is_ebpf = true; |
a8cb5f55 DB |
246 | |
247 | return 0; | |
248 | } | |
249 | ||
f4eaed28 DB |
250 | static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) |
251 | { | |
3239534a DC |
252 | struct bpf_prog *filter = cfg->filter; |
253 | ||
254 | if (filter) { | |
255 | if (cfg->is_ebpf) | |
256 | bpf_prog_put(filter); | |
257 | else | |
258 | bpf_prog_destroy(filter); | |
259 | } | |
f4eaed28 DB |
260 | |
261 | kfree(cfg->bpf_ops); | |
262 | kfree(cfg->bpf_name); | |
263 | } | |
264 | ||
265 | static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, | |
266 | struct tcf_bpf_cfg *cfg) | |
267 | { | |
268 | cfg->is_ebpf = tcf_bpf_is_ebpf(prog); | |
cff82457 | 269 | /* updates to prog->filter are prevented, since it's called either |
2142236b | 270 | * with tcf lock or during final cleanup in rcu callback |
cff82457 AS |
271 | */ |
272 | cfg->filter = rcu_dereference_protected(prog->filter, 1); | |
f4eaed28 DB |
273 | |
274 | cfg->bpf_ops = prog->bpf_ops; | |
275 | cfg->bpf_name = prog->bpf_name; | |
276 | } | |
277 | ||
a8cb5f55 | 278 | static int tcf_bpf_init(struct net *net, struct nlattr *nla, |
a85a970a | 279 | struct nlattr *est, struct tc_action **act, |
789871bb | 280 | int replace, int bind, bool rtnl_held, |
abbb0d33 VB |
281 | struct tcf_proto *tp, u32 flags, |
282 | struct netlink_ext_ack *extack) | |
a8cb5f55 | 283 | { |
ddf97ccd | 284 | struct tc_action_net *tn = net_generic(net, bpf_net_id); |
a8cb5f55 | 285 | struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; |
4e181004 | 286 | struct tcf_chain *goto_ch = NULL; |
f4eaed28 | 287 | struct tcf_bpf_cfg cfg, old; |
a8cb5f55 DB |
288 | struct tc_act_bpf *parm; |
289 | struct tcf_bpf *prog; | |
a8cb5f55 | 290 | bool is_bpf, is_ebpf; |
a5c90b29 | 291 | int ret, res = 0; |
7be8ef2c | 292 | u32 index; |
a8cb5f55 DB |
293 | |
294 | if (!nla) | |
295 | return -EINVAL; | |
296 | ||
8cb08174 JB |
297 | ret = nla_parse_nested_deprecated(tb, TCA_ACT_BPF_MAX, nla, |
298 | act_bpf_policy, NULL); | |
a8cb5f55 DB |
299 | if (ret < 0) |
300 | return ret; | |
301 | ||
a5c90b29 | 302 | if (!tb[TCA_ACT_BPF_PARMS]) |
a8cb5f55 DB |
303 | return -EINVAL; |
304 | ||
305 | parm = nla_data(tb[TCA_ACT_BPF_PARMS]); | |
7be8ef2c DL |
306 | index = parm->index; |
307 | ret = tcf_idr_check_alloc(tn, &index, act, bind); | |
0190c1d4 | 308 | if (!ret) { |
7be8ef2c | 309 | ret = tcf_idr_create(tn, index, est, act, |
e3822678 | 310 | &act_bpf_ops, bind, true, 0); |
0190c1d4 | 311 | if (ret < 0) { |
7be8ef2c | 312 | tcf_idr_cleanup(tn, index); |
a5c90b29 | 313 | return ret; |
0190c1d4 | 314 | } |
d23b8ad8 | 315 | |
a5c90b29 | 316 | res = ACT_P_CREATED; |
0190c1d4 | 317 | } else if (ret > 0) { |
a8cb5f55 | 318 | /* Don't override defaults. */ |
d23b8ad8 | 319 | if (bind) |
a5c90b29 | 320 | return 0; |
a8cb5f55 | 321 | |
4e8ddd7f VB |
322 | if (!replace) { |
323 | tcf_idr_release(*act, bind); | |
a5c90b29 | 324 | return -EEXIST; |
4e8ddd7f | 325 | } |
0190c1d4 VB |
326 | } else { |
327 | return ret; | |
d23b8ad8 JP |
328 | } |
329 | ||
4e181004 DC |
330 | ret = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); |
331 | if (ret < 0) | |
332 | goto release_idr; | |
333 | ||
a5c90b29 DB |
334 | is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; |
335 | is_ebpf = tb[TCA_ACT_BPF_FD]; | |
336 | ||
337 | if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) { | |
338 | ret = -EINVAL; | |
4e181004 | 339 | goto put_chain; |
a5c90b29 DB |
340 | } |
341 | ||
342 | memset(&cfg, 0, sizeof(cfg)); | |
343 | ||
344 | ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : | |
345 | tcf_bpf_init_from_efd(tb, &cfg); | |
346 | if (ret < 0) | |
4e181004 | 347 | goto put_chain; |
a5c90b29 | 348 | |
a85a970a | 349 | prog = to_bpf(*act); |
a8cb5f55 | 350 | |
653cd284 | 351 | spin_lock_bh(&prog->tcf_lock); |
faa54be4 | 352 | if (res != ACT_P_CREATED) |
f4eaed28 DB |
353 | tcf_bpf_prog_fill_cfg(prog, &old); |
354 | ||
a8cb5f55 DB |
355 | prog->bpf_ops = cfg.bpf_ops; |
356 | prog->bpf_name = cfg.bpf_name; | |
357 | ||
358 | if (cfg.bpf_num_ops) | |
359 | prog->bpf_num_ops = cfg.bpf_num_ops; | |
a8cb5f55 | 360 | |
4e181004 | 361 | goto_ch = tcf_action_set_ctrlact(*act, parm->action, goto_ch); |
cff82457 | 362 | rcu_assign_pointer(prog->filter, cfg.filter); |
653cd284 | 363 | spin_unlock_bh(&prog->tcf_lock); |
d23b8ad8 | 364 | |
4e181004 DC |
365 | if (goto_ch) |
366 | tcf_chain_put_by_act(goto_ch); | |
367 | ||
e49d8c22 | 368 | if (res != ACT_P_CREATED) { |
cff82457 AS |
369 | /* make sure the program being replaced is no longer executing */ |
370 | synchronize_rcu(); | |
f4eaed28 | 371 | tcf_bpf_cfg_cleanup(&old); |
cff82457 | 372 | } |
a8cb5f55 | 373 | |
a5c90b29 | 374 | return res; |
d23b8ad8 | 375 | |
4e181004 DC |
376 | put_chain: |
377 | if (goto_ch) | |
378 | tcf_chain_put_by_act(goto_ch); | |
379 | ||
380 | release_idr: | |
381 | tcf_idr_release(*act, bind); | |
d23b8ad8 JP |
382 | return ret; |
383 | } | |
384 | ||
9a63b255 | 385 | static void tcf_bpf_cleanup(struct tc_action *act) |
d23b8ad8 | 386 | { |
f4eaed28 | 387 | struct tcf_bpf_cfg tmp; |
ddf06c1e | 388 | |
a85a970a | 389 | tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp); |
f4eaed28 | 390 | tcf_bpf_cfg_cleanup(&tmp); |
d23b8ad8 JP |
391 | } |
392 | ||
ddf97ccd WC |
393 | static int tcf_bpf_walker(struct net *net, struct sk_buff *skb, |
394 | struct netlink_callback *cb, int type, | |
41780105 AA |
395 | const struct tc_action_ops *ops, |
396 | struct netlink_ext_ack *extack) | |
ddf97ccd WC |
397 | { |
398 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
399 | ||
b3620145 | 400 | return tcf_generic_walker(tn, skb, cb, type, ops, extack); |
ddf97ccd WC |
401 | } |
402 | ||
f061b48c | 403 | static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index) |
ddf97ccd WC |
404 | { |
405 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
406 | ||
65a206c0 | 407 | return tcf_idr_search(tn, a, index); |
ddf97ccd WC |
408 | } |
409 | ||
a8cb5f55 DB |
410 | static struct tc_action_ops act_bpf_ops __read_mostly = { |
411 | .kind = "bpf", | |
eddd2cf1 | 412 | .id = TCA_ID_BPF, |
a8cb5f55 | 413 | .owner = THIS_MODULE, |
2fbec27f | 414 | .act = tcf_bpf_act, |
a8cb5f55 DB |
415 | .dump = tcf_bpf_dump, |
416 | .cleanup = tcf_bpf_cleanup, | |
417 | .init = tcf_bpf_init, | |
ddf97ccd WC |
418 | .walk = tcf_bpf_walker, |
419 | .lookup = tcf_bpf_search, | |
a85a970a | 420 | .size = sizeof(struct tcf_bpf), |
ddf97ccd WC |
421 | }; |
422 | ||
423 | static __net_init int bpf_init_net(struct net *net) | |
424 | { | |
425 | struct tc_action_net *tn = net_generic(net, bpf_net_id); | |
426 | ||
981471bd | 427 | return tc_action_net_init(net, tn, &act_bpf_ops); |
ddf97ccd WC |
428 | } |
429 | ||
039af9c6 | 430 | static void __net_exit bpf_exit_net(struct list_head *net_list) |
ddf97ccd | 431 | { |
039af9c6 | 432 | tc_action_net_exit(net_list, bpf_net_id); |
ddf97ccd WC |
433 | } |
434 | ||
435 | static struct pernet_operations bpf_net_ops = { | |
436 | .init = bpf_init_net, | |
039af9c6 | 437 | .exit_batch = bpf_exit_net, |
ddf97ccd WC |
438 | .id = &bpf_net_id, |
439 | .size = sizeof(struct tc_action_net), | |
d23b8ad8 JP |
440 | }; |
441 | ||
442 | static int __init bpf_init_module(void) | |
443 | { | |
ddf97ccd | 444 | return tcf_register_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
445 | } |
446 | ||
447 | static void __exit bpf_cleanup_module(void) | |
448 | { | |
ddf97ccd | 449 | tcf_unregister_action(&act_bpf_ops, &bpf_net_ops); |
d23b8ad8 JP |
450 | } |
451 | ||
452 | module_init(bpf_init_module); | |
453 | module_exit(bpf_cleanup_module); | |
454 | ||
455 | MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); | |
456 | MODULE_DESCRIPTION("TC BPF based action"); | |
457 | MODULE_LICENSE("GPL v2"); |