1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/act_gact.c		Generic actions
4 *
5 * copyright 	Jamal Hadi Salim (2002-4)
6 */
7
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <linux/string.h>
11#include <linux/errno.h>
12#include <linux/skbuff.h>
13#include <linux/rtnetlink.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <net/netlink.h>
17#include <net/pkt_sched.h>
18#include <net/pkt_cls.h>
19#include <linux/tc_act/tc_gact.h>
20#include <net/tc_act/tc_gact.h>
21#include <net/tc_wrapper.h>
22
23static struct tc_action_ops act_gact_ops;
24
25#ifdef CONFIG_GACT_PROB
26static int gact_net_rand(struct tcf_gact *gact)
27{
28	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
29	if (get_random_u32_below(gact->tcfg_pval))
30		return gact->tcf_action;
31	return gact->tcfg_paction;
32}
33
34static int gact_determ(struct tcf_gact *gact)
35{
36	u32 pack = atomic_inc_return(&gact->packets);
37
38	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
39	if (pack % gact->tcfg_pval)
40		return gact->tcf_action;
41	return gact->tcfg_paction;
42}
43
44typedef int (*g_rand)(struct tcf_gact *gact);
45static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
46#endif /* CONFIG_GACT_PROB */
47
48static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
49	[TCA_GACT_PARMS]	= { .len = sizeof(struct tc_gact) },
50	[TCA_GACT_PROB]		= { .len = sizeof(struct tc_gact_p) },
51};
52
53static int tcf_gact_init(struct net *net, struct nlattr *nla,
54			 struct nlattr *est, struct tc_action **a,
55			 struct tcf_proto *tp, u32 flags,
56			 struct netlink_ext_ack *extack)
57{
58	struct tc_action_net *tn = net_generic(net, act_gact_ops.net_id);
59	bool bind = flags & TCA_ACT_FLAGS_BIND;
60	struct nlattr *tb[TCA_GACT_MAX + 1];
61	struct tcf_chain *goto_ch = NULL;
62	struct tc_gact *parm;
63	struct tcf_gact *gact;
64	int ret = 0;
65	u32 index;
66	int err;
67#ifdef CONFIG_GACT_PROB
68	struct tc_gact_p *p_parm = NULL;
69#endif
70
71	if (nla == NULL)
72		return -EINVAL;
73
74	err = nla_parse_nested_deprecated(tb, TCA_GACT_MAX, nla, gact_policy,
75					  NULL);
76	if (err < 0)
77		return err;
78
79	if (tb[TCA_GACT_PARMS] == NULL)
80		return -EINVAL;
81	parm = nla_data(tb[TCA_GACT_PARMS]);
82	index = parm->index;
83
84#ifndef CONFIG_GACT_PROB
85	if (tb[TCA_GACT_PROB] != NULL)
86		return -EOPNOTSUPP;
87#else
88	if (tb[TCA_GACT_PROB]) {
89		p_parm = nla_data(tb[TCA_GACT_PROB]);
90		if (p_parm->ptype >= MAX_RAND)
91			return -EINVAL;
92		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
93			NL_SET_ERR_MSG(extack,
94				       "goto chain not allowed on fallback");
95			return -EINVAL;
96		}
97	}
98#endif
99
100	err = tcf_idr_check_alloc(tn, &index, a, bind);
101	if (!err) {
102		ret = tcf_idr_create_from_flags(tn, index, est, a,
103						&act_gact_ops, bind, flags);
104		if (ret) {
105			tcf_idr_cleanup(tn, index);
106			return ret;
107		}
108		ret = ACT_P_CREATED;
109	} else if (err > 0) {
110		if (bind)/* dont override defaults */
111			return ACT_P_BOUND;
112		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
113			tcf_idr_release(*a, bind);
114			return -EEXIST;
115		}
116	} else {
117		return err;
118	}
119
120	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
121	if (err < 0)
122		goto release_idr;
123	gact = to_gact(*a);
124
125	spin_lock_bh(&gact->tcf_lock);
126	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
127#ifdef CONFIG_GACT_PROB
128	if (p_parm) {
129		gact->tcfg_paction = p_parm->paction;
130		gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
131		/* Make sure tcfg_pval is written before tcfg_ptype
132		 * coupled with smp_rmb() in gact_net_rand() & gact_determ()
133		 */
134		smp_wmb();
135		gact->tcfg_ptype   = p_parm->ptype;
136	}
137#endif
138	spin_unlock_bh(&gact->tcf_lock);
139
140	if (goto_ch)
141		tcf_chain_put_by_act(goto_ch);
142
143	return ret;
144release_idr:
145	tcf_idr_release(*a, bind);
146	return err;
147}
148
149TC_INDIRECT_SCOPE int tcf_gact_act(struct sk_buff *skb,
150				   const struct tc_action *a,
151				   struct tcf_result *res)
152{
153	struct tcf_gact *gact = to_gact(a);
154	int action = READ_ONCE(gact->tcf_action);
155
156#ifdef CONFIG_GACT_PROB
157	{
158	u32 ptype = READ_ONCE(gact->tcfg_ptype);
159
160	if (ptype)
161		action = gact_rand[ptype](gact);
162	}
163#endif
164	tcf_action_update_bstats(&gact->common, skb);
165	if (action == TC_ACT_SHOT)
166		tcf_action_inc_drop_qstats(&gact->common);
167
168	tcf_lastuse_update(&gact->tcf_tm);
169
170	return action;
171}
172
173static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u64 packets,
174				  u64 drops, u64 lastuse, bool hw)
175{
176	struct tcf_gact *gact = to_gact(a);
177	int action = READ_ONCE(gact->tcf_action);
178	struct tcf_t *tm = &gact->tcf_tm;
179
180	tcf_action_update_stats(a, bytes, packets,
181				action == TC_ACT_SHOT ? packets : drops, hw);
182	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
183}
184
185static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
186			 int bind, int ref)
187{
188	unsigned char *b = skb_tail_pointer(skb);
189	struct tcf_gact *gact = to_gact(a);
190	struct tc_gact opt = {
191		.index   = gact->tcf_index,
192		.refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
193		.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
194	};
195	struct tcf_t t;
196
197	spin_lock_bh(&gact->tcf_lock);
198	opt.action = gact->tcf_action;
199	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
200		goto nla_put_failure;
201#ifdef CONFIG_GACT_PROB
202	if (gact->tcfg_ptype) {
203		struct tc_gact_p p_opt = {
204			.paction = gact->tcfg_paction,
205			.pval    = gact->tcfg_pval,
206			.ptype   = gact->tcfg_ptype,
207		};
208
209		if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
210			goto nla_put_failure;
211	}
212#endif
213	tcf_tm_dump(&t, &gact->tcf_tm);
214	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
215		goto nla_put_failure;
216	spin_unlock_bh(&gact->tcf_lock);
217
218	return skb->len;
219
220nla_put_failure:
221	spin_unlock_bh(&gact->tcf_lock);
222	nlmsg_trim(skb, b);
223	return -1;
224}
225
226static size_t tcf_gact_get_fill_size(const struct tc_action *act)
227{
228	size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
229
230#ifdef CONFIG_GACT_PROB
231	if (to_gact(act)->tcfg_ptype)
232		/* TCA_GACT_PROB */
233		sz += nla_total_size(sizeof(struct tc_gact_p));
234#endif
235
236	return sz;
237}
238
239static int tcf_gact_offload_act_setup(struct tc_action *act, void *entry_data,
240				      u32 *index_inc, bool bind,
241				      struct netlink_ext_ack *extack)
242{
243	if (bind) {
244		struct flow_action_entry *entry = entry_data;
245
246		if (is_tcf_gact_ok(act)) {
247			entry->id = FLOW_ACTION_ACCEPT;
248		} else if (is_tcf_gact_shot(act)) {
249			entry->id = FLOW_ACTION_DROP;
250		} else if (is_tcf_gact_trap(act)) {
251			entry->id = FLOW_ACTION_TRAP;
252		} else if (is_tcf_gact_goto_chain(act)) {
253			entry->id = FLOW_ACTION_GOTO;
254			entry->chain_index = tcf_gact_goto_chain_index(act);
255		} else if (is_tcf_gact_continue(act)) {
256			NL_SET_ERR_MSG_MOD(extack, "Offload of \"continue\" action is not supported");
257			return -EOPNOTSUPP;
258		} else if (is_tcf_gact_reclassify(act)) {
259			NL_SET_ERR_MSG_MOD(extack, "Offload of \"reclassify\" action is not supported");
260			return -EOPNOTSUPP;
261		} else if (is_tcf_gact_pipe(act)) {
262			NL_SET_ERR_MSG_MOD(extack, "Offload of \"pipe\" action is not supported");
263			return -EOPNOTSUPP;
264		} else {
265			NL_SET_ERR_MSG_MOD(extack, "Unsupported generic action offload");
266			return -EOPNOTSUPP;
267		}
268		*index_inc = 1;
269	} else {
270		struct flow_offload_action *fl_action = entry_data;
271
272		if (is_tcf_gact_ok(act))
273			fl_action->id = FLOW_ACTION_ACCEPT;
274		else if (is_tcf_gact_shot(act))
275			fl_action->id = FLOW_ACTION_DROP;
276		else if (is_tcf_gact_trap(act))
277			fl_action->id = FLOW_ACTION_TRAP;
278		else if (is_tcf_gact_goto_chain(act))
279			fl_action->id = FLOW_ACTION_GOTO;
280		else
281			return -EOPNOTSUPP;
282	}
283
284	return 0;
285}
286
287static struct tc_action_ops act_gact_ops = {
288	.kind		=	"gact",
289	.id		=	TCA_ID_GACT,
290	.owner		=	THIS_MODULE,
291	.act		=	tcf_gact_act,
292	.stats_update	=	tcf_gact_stats_update,
293	.dump		=	tcf_gact_dump,
294	.init		=	tcf_gact_init,
295	.get_fill_size	=	tcf_gact_get_fill_size,
296	.offload_act_setup =	tcf_gact_offload_act_setup,
297	.size		=	sizeof(struct tcf_gact),
298};
299MODULE_ALIAS_NET_ACT("gact");
300
301static __net_init int gact_init_net(struct net *net)
302{
303	struct tc_action_net *tn = net_generic(net, act_gact_ops.net_id);
304
305	return tc_action_net_init(net, tn, &act_gact_ops);
306}
307
308static void __net_exit gact_exit_net(struct list_head *net_list)
309{
310	tc_action_net_exit(net_list, act_gact_ops.net_id);
311}
312
313static struct pernet_operations gact_net_ops = {
314	.init = gact_init_net,
315	.exit_batch = gact_exit_net,
316	.id   = &act_gact_ops.net_id,
317	.size = sizeof(struct tc_action_net),
318};
319
320MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
321MODULE_DESCRIPTION("Generic Classifier actions");
322MODULE_LICENSE("GPL");
323
324static int __init gact_init_module(void)
325{
326#ifdef CONFIG_GACT_PROB
327	pr_info("GACT probability on\n");
328#else
329	pr_info("GACT probability NOT on\n");
330#endif
331
332	return tcf_register_action(&act_gact_ops, &gact_net_ops);
333}
334
335static void __exit gact_cleanup_module(void)
336{
337	tcf_unregister_action(&act_gact_ops, &gact_net_ops);
338}
339
340module_init(gact_init_module);
341module_exit(gact_cleanup_module);
342