2 * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us>
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.
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>
18 #include <net/netlink.h>
19 #include <net/pkt_sched.h>
21 #include <linux/tc_act/tc_bpf.h>
22 #include <net/tc_act/tc_bpf.h>
24 #define BPF_TAB_MASK 15
25 #define ACT_BPF_NAME_LEN 256
28 struct bpf_prog *filter;
29 struct sock_filter *bpf_ops;
35 static unsigned int bpf_net_id;
36 static struct tc_action_ops act_bpf_ops;
38 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
39 struct tcf_result *res)
41 bool at_ingress = skb_at_tc_ingress(skb);
42 struct tcf_bpf *prog = to_bpf(act);
43 struct bpf_prog *filter;
44 int action, filter_res;
46 tcf_lastuse_update(&prog->tcf_tm);
47 bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
50 filter = rcu_dereference(prog->filter);
52 __skb_push(skb, skb->mac_len);
53 bpf_compute_data_end(skb);
54 filter_res = BPF_PROG_RUN(filter, skb);
55 __skb_pull(skb, skb->mac_len);
57 bpf_compute_data_end(skb);
58 filter_res = BPF_PROG_RUN(filter, skb);
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.
66 * In case a different well-known TC_ACT opcode has been
67 * returned, it will overwrite the default one.
69 * For everything else that is unkown, TC_ACT_UNSPEC is
74 case TC_ACT_RECLASSIFY:
81 qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats));
84 action = prog->tcf_action;
87 action = TC_ACT_UNSPEC;
94 static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog)
96 return !prog->bpf_ops;
99 static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog,
104 if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops))
107 nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops *
108 sizeof(struct sock_filter));
112 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
117 static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog,
122 if (prog->bpf_name &&
123 nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name))
126 nla = nla_reserve(skb, TCA_ACT_BPF_DIGEST,
127 sizeof(prog->filter->digest));
131 memcpy(nla_data(nla), prog->filter->digest, nla_len(nla));
136 static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
139 unsigned char *tp = skb_tail_pointer(skb);
140 struct tcf_bpf *prog = to_bpf(act);
141 struct tc_act_bpf opt = {
142 .index = prog->tcf_index,
143 .refcnt = prog->tcf_refcnt - ref,
144 .bindcnt = prog->tcf_bindcnt - bind,
145 .action = prog->tcf_action,
150 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
151 goto nla_put_failure;
153 if (tcf_bpf_is_ebpf(prog))
154 ret = tcf_bpf_dump_ebpf_info(prog, skb);
156 ret = tcf_bpf_dump_bpf_info(prog, skb);
158 goto nla_put_failure;
160 tcf_tm_dump(&tm, &prog->tcf_tm);
161 if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm,
163 goto nla_put_failure;
172 static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
173 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) },
174 [TCA_ACT_BPF_FD] = { .type = NLA_U32 },
175 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING,
176 .len = ACT_BPF_NAME_LEN },
177 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 },
178 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY,
179 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
182 static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
184 struct sock_filter *bpf_ops;
185 struct sock_fprog_kern fprog_tmp;
187 u16 bpf_size, bpf_num_ops;
190 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]);
191 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
194 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
195 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS]))
198 bpf_ops = kzalloc(bpf_size, GFP_KERNEL);
202 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size);
204 fprog_tmp.len = bpf_num_ops;
205 fprog_tmp.filter = bpf_ops;
207 ret = bpf_prog_create(&fp, &fprog_tmp);
213 cfg->bpf_ops = bpf_ops;
214 cfg->bpf_num_ops = bpf_num_ops;
216 cfg->is_ebpf = false;
221 static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
227 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]);
229 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT);
233 if (tb[TCA_ACT_BPF_NAME]) {
234 name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL);
241 cfg->bpf_name = name;
248 static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg)
251 bpf_prog_put(cfg->filter);
253 bpf_prog_destroy(cfg->filter);
256 kfree(cfg->bpf_name);
259 static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
260 struct tcf_bpf_cfg *cfg)
262 cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
263 /* updates to prog->filter are prevented, since it's called either
264 * with rtnl lock or during final cleanup in rcu callback
266 cfg->filter = rcu_dereference_protected(prog->filter, 1);
268 cfg->bpf_ops = prog->bpf_ops;
269 cfg->bpf_name = prog->bpf_name;
272 static int tcf_bpf_init(struct net *net, struct nlattr *nla,
273 struct nlattr *est, struct tc_action **act,
274 int replace, int bind)
276 struct tc_action_net *tn = net_generic(net, bpf_net_id);
277 struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
278 struct tcf_bpf_cfg cfg, old;
279 struct tc_act_bpf *parm;
280 struct tcf_bpf *prog;
281 bool is_bpf, is_ebpf;
287 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy);
291 if (!tb[TCA_ACT_BPF_PARMS])
294 parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
296 if (!tcf_hash_check(tn, parm->index, act, bind)) {
297 ret = tcf_hash_create(tn, parm->index, est, act,
298 &act_bpf_ops, bind, true);
304 /* Don't override defaults. */
308 tcf_hash_release(*act, bind);
313 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
314 is_ebpf = tb[TCA_ACT_BPF_FD];
316 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf)) {
321 memset(&cfg, 0, sizeof(cfg));
323 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) :
324 tcf_bpf_init_from_efd(tb, &cfg);
331 if (res != ACT_P_CREATED)
332 tcf_bpf_prog_fill_cfg(prog, &old);
334 prog->bpf_ops = cfg.bpf_ops;
335 prog->bpf_name = cfg.bpf_name;
338 prog->bpf_num_ops = cfg.bpf_num_ops;
340 prog->tcf_action = parm->action;
341 rcu_assign_pointer(prog->filter, cfg.filter);
343 if (res == ACT_P_CREATED) {
344 tcf_hash_insert(tn, *act);
346 /* make sure the program being replaced is no longer executing */
348 tcf_bpf_cfg_cleanup(&old);
353 if (res == ACT_P_CREATED)
354 tcf_hash_cleanup(*act, est);
359 static void tcf_bpf_cleanup(struct tc_action *act, int bind)
361 struct tcf_bpf_cfg tmp;
363 tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp);
364 tcf_bpf_cfg_cleanup(&tmp);
367 static int tcf_bpf_walker(struct net *net, struct sk_buff *skb,
368 struct netlink_callback *cb, int type,
369 const struct tc_action_ops *ops)
371 struct tc_action_net *tn = net_generic(net, bpf_net_id);
373 return tcf_generic_walker(tn, skb, cb, type, ops);
376 static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index)
378 struct tc_action_net *tn = net_generic(net, bpf_net_id);
380 return tcf_hash_search(tn, a, index);
383 static struct tc_action_ops act_bpf_ops __read_mostly = {
386 .owner = THIS_MODULE,
388 .dump = tcf_bpf_dump,
389 .cleanup = tcf_bpf_cleanup,
390 .init = tcf_bpf_init,
391 .walk = tcf_bpf_walker,
392 .lookup = tcf_bpf_search,
393 .size = sizeof(struct tcf_bpf),
396 static __net_init int bpf_init_net(struct net *net)
398 struct tc_action_net *tn = net_generic(net, bpf_net_id);
400 return tc_action_net_init(tn, &act_bpf_ops, BPF_TAB_MASK);
403 static void __net_exit bpf_exit_net(struct net *net)
405 struct tc_action_net *tn = net_generic(net, bpf_net_id);
407 tc_action_net_exit(tn);
410 static struct pernet_operations bpf_net_ops = {
411 .init = bpf_init_net,
412 .exit = bpf_exit_net,
414 .size = sizeof(struct tc_action_net),
417 static int __init bpf_init_module(void)
419 return tcf_register_action(&act_bpf_ops, &bpf_net_ops);
422 static void __exit bpf_cleanup_module(void)
424 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops);
427 module_init(bpf_init_module);
428 module_exit(bpf_cleanup_module);
430 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
431 MODULE_DESCRIPTION("TC BPF based action");
432 MODULE_LICENSE("GPL v2");