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[karo-tx-linux.git] / net / sched / act_bpf.c
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>
16 #include <linux/bpf.h>
17
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
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 };
34
35 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
36                    struct tcf_result *res)
37 {
38         struct tcf_bpf *prog = act->priv;
39         int action, filter_res;
40         bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
41
42         if (unlikely(!skb_mac_header_was_set(skb)))
43                 return TC_ACT_UNSPEC;
44
45         spin_lock(&prog->tcf_lock);
46
47         prog->tcf_tm.lastuse = jiffies;
48         bstats_update(&prog->tcf_bstats, skb);
49
50         /* Needed here for accessing maps. */
51         rcu_read_lock();
52         if (at_ingress) {
53                 __skb_push(skb, skb->mac_len);
54                 filter_res = BPF_PROG_RUN(prog->filter, skb);
55                 __skb_pull(skb, skb->mac_len);
56         } else {
57                 filter_res = BPF_PROG_RUN(prog->filter, skb);
58         }
59         rcu_read_unlock();
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:
75                 action = filter_res;
76                 break;
77         case TC_ACT_SHOT:
78                 action = filter_res;
79                 prog->tcf_qstats.drops++;
80                 break;
81         case TC_ACT_UNSPEC:
82                 action = prog->tcf_action;
83                 break;
84         default:
85                 action = TC_ACT_UNSPEC;
86                 break;
87         }
88
89         spin_unlock(&prog->tcf_lock);
90         return action;
91 }
92
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 {
119         if (nla_put_u32(skb, TCA_ACT_BPF_FD, prog->bpf_fd))
120                 return -EMSGSIZE;
121
122         if (prog->bpf_name &&
123             nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name))
124                 return -EMSGSIZE;
125
126         return 0;
127 }
128
129 static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
130                         int bind, int ref)
131 {
132         unsigned char *tp = skb_tail_pointer(skb);
133         struct tcf_bpf *prog = act->priv;
134         struct tc_act_bpf opt = {
135                 .index   = prog->tcf_index,
136                 .refcnt  = prog->tcf_refcnt - ref,
137                 .bindcnt = prog->tcf_bindcnt - bind,
138                 .action  = prog->tcf_action,
139         };
140         struct tcf_t tm;
141         int ret;
142
143         if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
144                 goto nla_put_failure;
145
146         if (tcf_bpf_is_ebpf(prog))
147                 ret = tcf_bpf_dump_ebpf_info(prog, skb);
148         else
149                 ret = tcf_bpf_dump_bpf_info(prog, skb);
150         if (ret)
151                 goto nla_put_failure;
152
153         tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install);
154         tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse);
155         tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires);
156
157         if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm))
158                 goto nla_put_failure;
159
160         return skb->len;
161
162 nla_put_failure:
163         nlmsg_trim(skb, tp);
164         return -1;
165 }
166
167 static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
168         [TCA_ACT_BPF_PARMS]     = { .len = sizeof(struct tc_act_bpf) },
169         [TCA_ACT_BPF_FD]        = { .type = NLA_U32 },
170         [TCA_ACT_BPF_NAME]      = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN },
171         [TCA_ACT_BPF_OPS_LEN]   = { .type = NLA_U16 },
172         [TCA_ACT_BPF_OPS]       = { .type = NLA_BINARY,
173                                     .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
174 };
175
176 static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
177 {
178         struct sock_filter *bpf_ops;
179         struct sock_fprog_kern fprog_tmp;
180         struct bpf_prog *fp;
181         u16 bpf_size, bpf_num_ops;
182         int ret;
183
184         bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
185         if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
186                 return -EINVAL;
187
188         bpf_size = bpf_num_ops * sizeof(*bpf_ops);
189         if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
190                 return -EINVAL;
191
192         bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
193         if (bpf_ops == NULL)
194                 return -ENOMEM;
195
196         memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
197
198         fprog_tmp.len = bpf_num_ops;
199         fprog_tmp.filter = bpf_ops;
200
201         ret = bpf_prog_create(&fp, &fprog_tmp);
202         if (ret < 0) {
203                 kfree(bpf_ops);
204                 return ret;
205         }
206
207         cfg->bpf_ops = bpf_ops;
208         cfg->bpf_num_ops = bpf_num_ops;
209         cfg->filter = fp;
210
211         return 0;
212 }
213
214 static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
215 {
216         struct bpf_prog *fp;
217         char *name = NULL;
218         u32 bpf_fd;
219
220         bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]);
221
222         fp = bpf_prog_get(bpf_fd);
223         if (IS_ERR(fp))
224                 return PTR_ERR(fp);
225
226         if (fp->type != BPF_PROG_TYPE_SCHED_ACT) {
227                 bpf_prog_put(fp);
228                 return -EINVAL;
229         }
230
231         if (tb[TCA_ACT_BPF_NAME]) {
232                 name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]),
233                                nla_len(tb[TCA_ACT_BPF_NAME]),
234                                GFP_KERNEL);
235                 if (!name) {
236                         bpf_prog_put(fp);
237                         return -ENOMEM;
238                 }
239         }
240
241         cfg->bpf_fd = bpf_fd;
242         cfg->bpf_name = name;
243         cfg->filter = fp;
244
245         return 0;
246 }
247
248 static int tcf_bpf_init(struct net *net, struct nlattr *nla,
249                         struct nlattr *est, struct tc_action *act,
250                         int replace, int bind)
251 {
252         struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
253         struct tc_act_bpf *parm;
254         struct tcf_bpf *prog;
255         struct tcf_bpf_cfg cfg;
256         bool is_bpf, is_ebpf;
257         int ret;
258
259         if (!nla)
260                 return -EINVAL;
261
262         ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
263         if (ret < 0)
264                 return ret;
265
266         is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
267         is_ebpf = tb[TCA_ACT_BPF_FD];
268
269         if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) ||
270             !tb[TCA_ACT_BPF_PARMS])
271                 return -EINVAL;
272
273         parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
274
275         memset(&cfg, 0, sizeof(cfg));
276
277         ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
278                        tcf_bpf_init_from_efd(tb, &cfg);
279         if (ret < 0)
280                 return ret;
281
282         if (!tcf_hash_check(parm->index, act, bind)) {
283                 ret = tcf_hash_create(parm->index, est, act,
284                                       sizeof(*prog), bind);
285                 if (ret < 0)
286                         goto destroy_fp;
287
288                 ret = ACT_P_CREATED;
289         } else {
290                 /* Don't override defaults. */
291                 if (bind)
292                         goto destroy_fp;
293
294                 tcf_hash_release(act, bind);
295                 if (!replace) {
296                         ret = -EEXIST;
297                         goto destroy_fp;
298                 }
299         }
300
301         prog = to_bpf(act);
302         spin_lock_bh(&prog->tcf_lock);
303
304         prog->bpf_ops = cfg.bpf_ops;
305         prog->bpf_name = cfg.bpf_name;
306
307         if (cfg.bpf_num_ops)
308                 prog->bpf_num_ops = cfg.bpf_num_ops;
309         if (cfg.bpf_fd)
310                 prog->bpf_fd = cfg.bpf_fd;
311
312         prog->tcf_action = parm->action;
313         prog->filter = cfg.filter;
314
315         spin_unlock_bh(&prog->tcf_lock);
316
317         if (ret == ACT_P_CREATED)
318                 tcf_hash_insert(act);
319
320         return ret;
321
322 destroy_fp:
323         if (is_ebpf)
324                 bpf_prog_put(cfg.filter);
325         else
326                 bpf_prog_destroy(cfg.filter);
327
328         kfree(cfg.bpf_ops);
329         kfree(cfg.bpf_name);
330
331         return ret;
332 }
333
334 static void tcf_bpf_cleanup(struct tc_action *act, int bind)
335 {
336         const struct tcf_bpf *prog = act->priv;
337
338         if (tcf_bpf_is_ebpf(prog))
339                 bpf_prog_put(prog->filter);
340         else
341                 bpf_prog_destroy(prog->filter);
342 }
343
344 static struct tc_action_ops act_bpf_ops __read_mostly = {
345         .kind           =       "bpf",
346         .type           =       TCA_ACT_BPF,
347         .owner          =       THIS_MODULE,
348         .act            =       tcf_bpf,
349         .dump           =       tcf_bpf_dump,
350         .cleanup        =       tcf_bpf_cleanup,
351         .init           =       tcf_bpf_init,
352 };
353
354 static int __init bpf_init_module(void)
355 {
356         return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK);
357 }
358
359 static void __exit bpf_cleanup_module(void)
360 {
361         tcf_unregister_action(&act_bpf_ops);
362 }
363
364 module_init(bpf_init_module);
365 module_exit(bpf_cleanup_module);
366
367 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
368 MODULE_DESCRIPTION("TC BPF based action");
369 MODULE_LICENSE("GPL v2");