act_simple.c

  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	nla_strscpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
 76	spin_unlock_bh(&d->tcf_lock);
 77	if (goto_ch)
 78		tcf_chain_put_by_act(goto_ch);
 79	return 0;
 80}
 81
 82static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
 83	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },
 84	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },
 85};
 86
 87static int tcf_simp_init(struct net *net, struct nlattr *nla,
 88			 struct nlattr *est, struct tc_action **a,
 89			 struct tcf_proto *tp, u32 flags,
 90			 struct netlink_ext_ack *extack)
 91{
 92	struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
 93	bool bind = flags & TCA_ACT_FLAGS_BIND;
 94	struct nlattr *tb[TCA_DEF_MAX + 1];
 95	struct tcf_chain *goto_ch = NULL;
 96	struct tc_defact *parm;
 97	struct tcf_defact *d;
 98	bool exists = false;
 99	int ret = 0, err;
100	u32 index;
101
102	if (nla == NULL)
103		return -EINVAL;
104
105	err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
106					  NULL);
107	if (err < 0)
108		return err;
109
110	if (tb[TCA_DEF_PARMS] == NULL)
111		return -EINVAL;
112
113	parm = nla_data(tb[TCA_DEF_PARMS]);
114	index = parm->index;
115	err = tcf_idr_check_alloc(tn, &index, a, bind);
116	if (err < 0)
117		return err;
118	exists = err;
119	if (exists && bind)
120		return ACT_P_BOUND;
121
122	if (tb[TCA_DEF_DATA] == NULL) {
123		if (exists)
124			tcf_idr_release(*a, bind);
125		else
126			tcf_idr_cleanup(tn, index);
127		return -EINVAL;
128	}
129
130	if (!exists) {
131		ret = tcf_idr_create(tn, index, est, a,
132				     &act_simp_ops, bind, false, flags);
133		if (ret) {
134			tcf_idr_cleanup(tn, index);
135			return ret;
136		}
137
138		d = to_defact(*a);
139		err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
140					       extack);
141		if (err < 0)
142			goto release_idr;
143
144		err = alloc_defdata(d, tb[TCA_DEF_DATA]);
145		if (err < 0)
146			goto put_chain;
147
148		tcf_action_set_ctrlact(*a, parm->action, goto_ch);
149		ret = ACT_P_CREATED;
150	} else {
151		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
152			err = -EEXIST;
153			goto release_idr;
154		}
155
156		err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
157		if (err)
158			goto release_idr;
159	}
160
161	return ret;
162put_chain:
163	if (goto_ch)
164		tcf_chain_put_by_act(goto_ch);
165release_idr:
166	tcf_idr_release(*a, bind);
167	return err;
168}
169
170static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
171			 int bind, int ref)
172{
173	unsigned char *b = skb_tail_pointer(skb);
174	struct tcf_defact *d = to_defact(a);
175	struct tc_defact opt = {
176		.index   = d->tcf_index,
177		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
178		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
179	};
180	struct tcf_t t;
181
182	spin_lock_bh(&d->tcf_lock);
183	opt.action = d->tcf_action;
184	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
185	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
186		goto nla_put_failure;
187
188	tcf_tm_dump(&t, &d->tcf_tm);
189	if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
190		goto nla_put_failure;
191	spin_unlock_bh(&d->tcf_lock);
192
193	return skb->len;
194
195nla_put_failure:
196	spin_unlock_bh(&d->tcf_lock);
197	nlmsg_trim(skb, b);
198	return -1;
199}
200
201static struct tc_action_ops act_simp_ops = {
202	.kind		=	"simple",
203	.id		=	TCA_ID_SIMP,
204	.owner		=	THIS_MODULE,
205	.act		=	tcf_simp_act,
206	.dump		=	tcf_simp_dump,
207	.cleanup	=	tcf_simp_release,
208	.init		=	tcf_simp_init,
209	.size		=	sizeof(struct tcf_defact),
210};
211MODULE_ALIAS_NET_ACT("simple");
212
213static __net_init int simp_init_net(struct net *net)
214{
215	struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
216
217	return tc_action_net_init(net, tn, &act_simp_ops);
218}
219
220static void __net_exit simp_exit_net(struct list_head *net_list)
221{
222	tc_action_net_exit(net_list, act_simp_ops.net_id);
223}
224
225static struct pernet_operations simp_net_ops = {
226	.init = simp_init_net,
227	.exit_batch = simp_exit_net,
228	.id   = &act_simp_ops.net_id,
229	.size = sizeof(struct tc_action_net),
230};
231
232MODULE_AUTHOR("Jamal Hadi Salim(2005)");
233MODULE_DESCRIPTION("Simple example action");
234MODULE_LICENSE("GPL");
235
236static int __init simp_init_module(void)
237{
238	int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
239	if (!ret)
240		pr_info("Simple TC action Loaded\n");
241	return ret;
242}
243
244static void __exit simp_cleanup_module(void)
245{
246	tcf_unregister_action(&act_simp_ops, &simp_net_ops);
247}
248
249module_init(simp_init_module);
250module_exit(simp_cleanup_module);