blob: c7123e01c2cabc9c58bbe4d3be2c3836d7f5e2e2 [file] [log] [blame]
Jiri Pirkod23b8ad2015-01-15 09:52:39 +01001/*
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>
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010016#include <linux/bpf.h>
17
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010018#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
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010024#define BPF_TAB_MASK 15
25#define ACT_BPF_NAME_LEN 256
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010026
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010027struct tcf_bpf_cfg {
28 struct bpf_prog *filter;
29 struct sock_filter *bpf_ops;
Daniel Borkmannf4eaed22015-07-29 18:40:56 +020030 const char *bpf_name;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010031 u32 bpf_fd;
32 u16 bpf_num_ops;
Daniel Borkmannf4eaed22015-07-29 18:40:56 +020033 bool is_ebpf;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010034};
35
WANG Congddf97cc2016-02-22 15:57:53 -080036static int bpf_net_id;
37
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010038static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010039 struct tcf_result *res)
40{
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010041 struct tcf_bpf *prog = act->priv;
Alexei Starovoitovcff82452015-08-25 20:06:35 -070042 struct bpf_prog *filter;
Daniel Borkmannced585c2015-03-17 20:25:57 +010043 int action, filter_res;
Alexei Starovoitov34312052015-06-04 10:11:53 -070044 bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010045
Alexei Starovoitova1661512015-04-15 12:55:45 -070046 if (unlikely(!skb_mac_header_was_set(skb)))
47 return TC_ACT_UNSPEC;
48
Alexei Starovoitovcff82452015-08-25 20:06:35 -070049 tcf_lastuse_update(&prog->tcf_tm);
50 bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
Daniel Borkmannced585c2015-03-17 20:25:57 +010051
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010052 rcu_read_lock();
Alexei Starovoitovcff82452015-08-25 20:06:35 -070053 filter = rcu_dereference(prog->filter);
Alexei Starovoitov34312052015-06-04 10:11:53 -070054 if (at_ingress) {
55 __skb_push(skb, skb->mac_len);
Alexei Starovoitovdb58ba42016-05-05 19:49:12 -070056 bpf_compute_data_end(skb);
Alexei Starovoitovcff82452015-08-25 20:06:35 -070057 filter_res = BPF_PROG_RUN(filter, skb);
Alexei Starovoitov34312052015-06-04 10:11:53 -070058 __skb_pull(skb, skb->mac_len);
59 } else {
Alexei Starovoitovdb58ba42016-05-05 19:49:12 -070060 bpf_compute_data_end(skb);
Alexei Starovoitovcff82452015-08-25 20:06:35 -070061 filter_res = BPF_PROG_RUN(filter, skb);
Alexei Starovoitov34312052015-06-04 10:11:53 -070062 }
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010063 rcu_read_unlock();
Daniel Borkmannced585c2015-03-17 20:25:57 +010064
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:
Alexei Starovoitov27b29f62015-09-15 23:05:43 -070079 case TC_ACT_REDIRECT:
Daniel Borkmannced585c2015-03-17 20:25:57 +010080 action = filter_res;
81 break;
82 case TC_ACT_SHOT:
83 action = filter_res;
Alexei Starovoitovcff82452015-08-25 20:06:35 -070084 qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats));
Daniel Borkmannced585c2015-03-17 20:25:57 +010085 break;
86 case TC_ACT_UNSPEC:
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010087 action = prog->tcf_action;
Daniel Borkmannced585c2015-03-17 20:25:57 +010088 break;
89 default:
90 action = TC_ACT_UNSPEC;
91 break;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010092 }
93
Jiri Pirkod23b8ad2015-01-15 09:52:39 +010094 return action;
95}
96
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +010097static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog)
98{
99 return !prog->bpf_ops;
100}
101
102static 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
120static 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
133static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100134 int bind, int ref)
135{
136 unsigned char *tp = skb_tail_pointer(skb);
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100137 struct tcf_bpf *prog = act->priv;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100138 struct tc_act_bpf opt = {
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100139 .index = prog->tcf_index,
140 .refcnt = prog->tcf_refcnt - ref,
141 .bindcnt = prog->tcf_bindcnt - bind,
142 .action = prog->tcf_action,
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100143 };
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100144 struct tcf_t tm;
145 int ret;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100146
147 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
148 goto nla_put_failure;
149
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100150 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)
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100155 goto nla_put_failure;
156
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100157 tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install);
158 tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse);
159 tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires);
160
Nicolas Dichtel98545182016-04-26 10:06:18 +0200161 if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm,
162 TCA_ACT_BPF_PAD))
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100163 goto nla_put_failure;
164
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100165 return skb->len;
166
167nla_put_failure:
168 nlmsg_trim(skb, tp);
169 return -1;
170}
171
172static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
173 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100174 [TCA_ACT_BPF_FD] = { .type = NLA_U32 },
175 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN },
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100176 [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
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100181static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100182{
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100183 struct sock_filter *bpf_ops;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100184 struct sock_fprog_kern fprog_tmp;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100185 struct bpf_prog *fp;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100186 u16 bpf_size, bpf_num_ops;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100187 int ret;
188
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100189 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);
Daniel Borkmannfd3e6462015-01-22 10:58:19 +0100194 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
195 return -EINVAL;
196
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100197 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100198 if (bpf_ops == NULL)
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100199 return -ENOMEM;
200
201 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
202
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100203 fprog_tmp.len = bpf_num_ops;
204 fprog_tmp.filter = bpf_ops;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100205
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100206 ret = bpf_prog_create(&fp, &fprog_tmp);
207 if (ret < 0) {
208 kfree(bpf_ops);
209 return ret;
210 }
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100211
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100212 cfg->bpf_ops = bpf_ops;
213 cfg->bpf_num_ops = bpf_num_ops;
214 cfg->filter = fp;
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200215 cfg->is_ebpf = false;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100216
217 return 0;
218}
219
220static 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
228 fp = bpf_prog_get(bpf_fd);
229 if (IS_ERR(fp))
230 return PTR_ERR(fp);
231
232 if (fp->type != BPF_PROG_TYPE_SCHED_ACT) {
233 bpf_prog_put(fp);
234 return -EINVAL;
235 }
236
237 if (tb[TCA_ACT_BPF_NAME]) {
238 name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]),
239 nla_len(tb[TCA_ACT_BPF_NAME]),
240 GFP_KERNEL);
241 if (!name) {
242 bpf_prog_put(fp);
243 return -ENOMEM;
244 }
245 }
246
247 cfg->bpf_fd = bpf_fd;
248 cfg->bpf_name = name;
249 cfg->filter = fp;
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200250 cfg->is_ebpf = true;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100251
252 return 0;
253}
254
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200255static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg)
256{
257 if (cfg->is_ebpf)
258 bpf_prog_put(cfg->filter);
259 else
260 bpf_prog_destroy(cfg->filter);
261
262 kfree(cfg->bpf_ops);
263 kfree(cfg->bpf_name);
264}
265
266static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
267 struct tcf_bpf_cfg *cfg)
268{
269 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700270 /* updates to prog->filter are prevented, since it's called either
271 * with rtnl lock or during final cleanup in rcu callback
272 */
273 cfg->filter = rcu_dereference_protected(prog->filter, 1);
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200274
275 cfg->bpf_ops = prog->bpf_ops;
276 cfg->bpf_name = prog->bpf_name;
277}
278
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100279static int tcf_bpf_init(struct net *net, struct nlattr *nla,
280 struct nlattr *est, struct tc_action *act,
281 int replace, int bind)
282{
WANG Congddf97cc2016-02-22 15:57:53 -0800283 struct tc_action_net *tn = net_generic(net, bpf_net_id);
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100284 struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200285 struct tcf_bpf_cfg cfg, old;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100286 struct tc_act_bpf *parm;
287 struct tcf_bpf *prog;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100288 bool is_bpf, is_ebpf;
Daniel Borkmanna5c90b22015-08-03 16:21:57 +0200289 int ret, res = 0;
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100290
291 if (!nla)
292 return -EINVAL;
293
294 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
295 if (ret < 0)
296 return ret;
297
Daniel Borkmanna5c90b22015-08-03 16:21:57 +0200298 if (!tb[TCA_ACT_BPF_PARMS])
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100299 return -EINVAL;
300
301 parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
302
WANG Congddf97cc2016-02-22 15:57:53 -0800303 if (!tcf_hash_check(tn, parm->index, act, bind)) {
304 ret = tcf_hash_create(tn, parm->index, est, act,
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700305 sizeof(*prog), bind, true);
Daniel Borkmanna5c90b22015-08-03 16:21:57 +0200306 if (ret < 0)
307 return ret;
308
309 res = ACT_P_CREATED;
310 } else {
311 /* Don't override defaults. */
312 if (bind)
313 return 0;
314
315 tcf_hash_release(act, bind);
316 if (!replace)
317 return -EEXIST;
318 }
319
320 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
321 is_ebpf = tb[TCA_ACT_BPF_FD];
322
323 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
324 ret = -EINVAL;
325 goto out;
326 }
327
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100328 memset(&cfg, 0, sizeof(cfg));
329
330 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
331 tcf_bpf_init_from_efd(tb, &cfg);
332 if (ret < 0)
Daniel Borkmanna5c90b22015-08-03 16:21:57 +0200333 goto out;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100334
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100335 prog = to_bpf(act);
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700336 ASSERT_RTNL();
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100337
Alexei Starovoitovfaa54be2015-08-25 20:06:32 -0700338 if (res != ACT_P_CREATED)
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200339 tcf_bpf_prog_fill_cfg(prog, &old);
340
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100341 prog->bpf_ops = cfg.bpf_ops;
342 prog->bpf_name = cfg.bpf_name;
343
344 if (cfg.bpf_num_ops)
345 prog->bpf_num_ops = cfg.bpf_num_ops;
346 if (cfg.bpf_fd)
347 prog->bpf_fd = cfg.bpf_fd;
348
349 prog->tcf_action = parm->action;
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700350 rcu_assign_pointer(prog->filter, cfg.filter);
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100351
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700352 if (res == ACT_P_CREATED) {
WANG Congddf97cc2016-02-22 15:57:53 -0800353 tcf_hash_insert(tn, act);
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700354 } else {
355 /* make sure the program being replaced is no longer executing */
356 synchronize_rcu();
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200357 tcf_bpf_cfg_cleanup(&old);
Alexei Starovoitovcff82452015-08-25 20:06:35 -0700358 }
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100359
Daniel Borkmanna5c90b22015-08-03 16:21:57 +0200360 return res;
361out:
362 if (res == ACT_P_CREATED)
363 tcf_hash_cleanup(act, est);
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100364
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100365 return ret;
366}
367
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100368static void tcf_bpf_cleanup(struct tc_action *act, int bind)
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100369{
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200370 struct tcf_bpf_cfg tmp;
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100371
Daniel Borkmannf4eaed22015-07-29 18:40:56 +0200372 tcf_bpf_prog_fill_cfg(act->priv, &tmp);
373 tcf_bpf_cfg_cleanup(&tmp);
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100374}
375
WANG Congddf97cc2016-02-22 15:57:53 -0800376static int tcf_bpf_walker(struct net *net, struct sk_buff *skb,
377 struct netlink_callback *cb, int type,
378 struct tc_action *a)
379{
380 struct tc_action_net *tn = net_generic(net, bpf_net_id);
381
382 return tcf_generic_walker(tn, skb, cb, type, a);
383}
384
385static int tcf_bpf_search(struct net *net, struct tc_action *a, u32 index)
386{
387 struct tc_action_net *tn = net_generic(net, bpf_net_id);
388
389 return tcf_hash_search(tn, a, index);
390}
391
Daniel Borkmanna8cb5f52015-03-20 15:11:12 +0100392static struct tc_action_ops act_bpf_ops __read_mostly = {
393 .kind = "bpf",
394 .type = TCA_ACT_BPF,
395 .owner = THIS_MODULE,
396 .act = tcf_bpf,
397 .dump = tcf_bpf_dump,
398 .cleanup = tcf_bpf_cleanup,
399 .init = tcf_bpf_init,
WANG Congddf97cc2016-02-22 15:57:53 -0800400 .walk = tcf_bpf_walker,
401 .lookup = tcf_bpf_search,
402};
403
404static __net_init int bpf_init_net(struct net *net)
405{
406 struct tc_action_net *tn = net_generic(net, bpf_net_id);
407
408 return tc_action_net_init(tn, &act_bpf_ops, BPF_TAB_MASK);
409}
410
411static void __net_exit bpf_exit_net(struct net *net)
412{
413 struct tc_action_net *tn = net_generic(net, bpf_net_id);
414
415 tc_action_net_exit(tn);
416}
417
418static struct pernet_operations bpf_net_ops = {
419 .init = bpf_init_net,
420 .exit = bpf_exit_net,
421 .id = &bpf_net_id,
422 .size = sizeof(struct tc_action_net),
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100423};
424
425static int __init bpf_init_module(void)
426{
WANG Congddf97cc2016-02-22 15:57:53 -0800427 return tcf_register_action(&act_bpf_ops, &bpf_net_ops);
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100428}
429
430static void __exit bpf_cleanup_module(void)
431{
WANG Congddf97cc2016-02-22 15:57:53 -0800432 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops);
Jiri Pirkod23b8ad2015-01-15 09:52:39 +0100433}
434
435module_init(bpf_init_module);
436module_exit(bpf_cleanup_module);
437
438MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
439MODULE_DESCRIPTION("TC BPF based action");
440MODULE_LICENSE("GPL v2");