1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/act_simple.c	Simple example of an action
4 *
5 * Authors:	Jamal Hadi Salim (2005-8)
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/skbuff.h>
13#include <linux/rtnetlink.h>
14#include <net/netlink.h>
15#include <net/pkt_sched.h>
16#include <net/pkt_cls.h>
17#include <net/tc_wrapper.h>
18
19#include <linux/tc_act/tc_defact.h>
20#include <net/tc_act/tc_defact.h>
21
22static struct tc_action_ops act_simp_ops;
23
24#define SIMP_MAX_DATA	32
25TC_INDIRECT_SCOPE int tcf_simp_act(struct sk_buff *skb,
26				   const struct tc_action *a,
27				   struct tcf_result *res)
28{
29	struct tcf_defact *d = to_defact(a);
30
31	spin_lock(&d->tcf_lock);
32	tcf_lastuse_update(&d->tcf_tm);
33	bstats_update(&d->tcf_bstats, skb);
34
35	/* print policy string followed by _ then packet count
36	 * Example if this was the 3rd packet and the string was "hello"
37	 * then it would look like "hello_3" (without quotes)
38	 */
39	pr_info("simple: %s_%llu\n",
40		(char *)d->tcfd_defdata,
41		u64_stats_read(&d->tcf_bstats.packets));
42	spin_unlock(&d->tcf_lock);
43	return d->tcf_action;
44}
45
46static void tcf_simp_release(struct tc_action *a)
47{
48	struct tcf_defact *d = to_defact(a);
49	kfree(d->tcfd_defdata);
50}
51
52static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)
53{
54	d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
55	if (unlikely(!d->tcfd_defdata))
56		return -ENOMEM;
57	nla_strscpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
58	return 0;
59}
60
61static int reset_policy(struct tc_action *a, const struct nlattr *defdata,
62			struct tc_defact *p, struct tcf_proto *tp,
63			struct netlink_ext_ack *extack)
64{
65	struct tcf_chain *goto_ch = NULL;
66	struct tcf_defact *d;
67	int err;
68
69	err = tcf_action_check_ctrlact(p->action, tp, &goto_ch, extack);
70	if (err < 0)
71		return err;
72	d = to_defact(a);
73	spin_lock_bh(&d->tcf_lock);
74	goto_ch = tcf_action_set_ctrlact(a, p->action, goto_ch);
75	memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
76	nla_strscpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
77	spin_unlock_bh(&d->tcf_lock);
78	if (goto_ch)
79		tcf_chain_put_by_act(goto_ch);
80	return 0;
81}
82
83static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
84	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },
85	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },
86};
87
88static int tcf_simp_init(struct net *net, struct nlattr *nla,
89			 struct nlattr *est, struct tc_action **a,
90			 struct tcf_proto *tp, u32 flags,
91			 struct netlink_ext_ack *extack)
92{
93	struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
94	bool bind = flags & TCA_ACT_FLAGS_BIND;
95	struct nlattr *tb[TCA_DEF_MAX + 1];
96	struct tcf_chain *goto_ch = NULL;
97	struct tc_defact *parm;
98	struct tcf_defact *d;
99	bool exists = false;
100	int ret = 0, err;
101	u32 index;
102
103	if (nla == NULL)
104		return -EINVAL;
105
106	err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
107					  NULL);
108	if (err < 0)
109		return err;
110
111	if (tb[TCA_DEF_PARMS] == NULL)
112		return -EINVAL;
113
114	parm = nla_data(tb[TCA_DEF_PARMS]);
115	index = parm->index;
116	err = tcf_idr_check_alloc(tn, &index, a, bind);
117	if (err < 0)
118		return err;
119	exists = err;
120	if (exists && bind)
121		return ACT_P_BOUND;
122
123	if (tb[TCA_DEF_DATA] == NULL) {
124		if (exists)
125			tcf_idr_release(*a, bind);
126		else
127			tcf_idr_cleanup(tn, index);
128		return -EINVAL;
129	}
130
131	if (!exists) {
132		ret = tcf_idr_create(tn, index, est, a,
133				     &act_simp_ops, bind, false, flags);
134		if (ret) {
135			tcf_idr_cleanup(tn, index);
136			return ret;
137		}
138
139		d = to_defact(*a);
140		err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
141					       extack);
142		if (err < 0)
143			goto release_idr;
144
145		err = alloc_defdata(d, tb[TCA_DEF_DATA]);
146		if (err < 0)
147			goto put_chain;
148
149		tcf_action_set_ctrlact(*a, parm->action, goto_ch);
150		ret = ACT_P_CREATED;
151	} else {
152		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
153			err = -EEXIST;
154			goto release_idr;
155		}
156
157		err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
158		if (err)
159			goto release_idr;
160	}
161
162	return ret;
163put_chain:
164	if (goto_ch)
165		tcf_chain_put_by_act(goto_ch);
166release_idr:
167	tcf_idr_release(*a, bind);
168	return err;
169}
170
171static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
172			 int bind, int ref)
173{
174	unsigned char *b = skb_tail_pointer(skb);
175	struct tcf_defact *d = to_defact(a);
176	struct tc_defact opt = {
177		.index   = d->tcf_index,
178		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
179		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
180	};
181	struct tcf_t t;
182
183	spin_lock_bh(&d->tcf_lock);
184	opt.action = d->tcf_action;
185	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
186	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
187		goto nla_put_failure;
188
189	tcf_tm_dump(&t, &d->tcf_tm);
190	if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
191		goto nla_put_failure;
192	spin_unlock_bh(&d->tcf_lock);
193
194	return skb->len;
195
196nla_put_failure:
197	spin_unlock_bh(&d->tcf_lock);
198	nlmsg_trim(skb, b);
199	return -1;
200}
201
202static struct tc_action_ops act_simp_ops = {
203	.kind		=	"simple",
204	.id		=	TCA_ID_SIMP,
205	.owner		=	THIS_MODULE,
206	.act		=	tcf_simp_act,
207	.dump		=	tcf_simp_dump,
208	.cleanup	=	tcf_simp_release,
209	.init		=	tcf_simp_init,
210	.size		=	sizeof(struct tcf_defact),
211};
212MODULE_ALIAS_NET_ACT("simple");
213
214static __net_init int simp_init_net(struct net *net)
215{
216	struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
217
218	return tc_action_net_init(net, tn, &act_simp_ops);
219}
220
221static void __net_exit simp_exit_net(struct list_head *net_list)
222{
223	tc_action_net_exit(net_list, act_simp_ops.net_id);
224}
225
226static struct pernet_operations simp_net_ops = {
227	.init = simp_init_net,
228	.exit_batch = simp_exit_net,
229	.id   = &act_simp_ops.net_id,
230	.size = sizeof(struct tc_action_net),
231};
232
233MODULE_AUTHOR("Jamal Hadi Salim(2005)");
234MODULE_DESCRIPTION("Simple example action");
235MODULE_LICENSE("GPL");
236
237static int __init simp_init_module(void)
238{
239	int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
240	if (!ret)
241		pr_info("Simple TC action Loaded\n");
242	return ret;
243}
244
245static void __exit simp_cleanup_module(void)
246{
247	tcf_unregister_action(&act_simp_ops, &simp_net_ops);
248}
249
250module_init(simp_init_module);
251module_exit(simp_cleanup_module);
252