1/*
2 * net/sched/simp.c	Simple example of an action
3 *
4 *		This program is free software; you can redistribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 *
9 * Authors:	Jamal Hadi Salim (2005-8)
10 *
11 */
12
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/skbuff.h>
18#include <linux/rtnetlink.h>
19#include <net/netlink.h>
20#include <net/pkt_sched.h>
21
22#define TCA_ACT_SIMP 22
23
24#include <linux/tc_act/tc_defact.h>
25#include <net/tc_act/tc_defact.h>
26
27#define SIMP_TAB_MASK     7
28static struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
29static u32 simp_idx_gen;
30static DEFINE_RWLOCK(simp_lock);
31
32static struct tcf_hashinfo simp_hash_info = {
33	.htab	=	tcf_simp_ht,
34	.hmask	=	SIMP_TAB_MASK,
35	.lock	=	&simp_lock,
36};
37
38#define SIMP_MAX_DATA	32
39static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
40		    struct tcf_result *res)
41{
42	struct tcf_defact *d = a->priv;
43
44	spin_lock(&d->tcf_lock);
45	d->tcf_tm.lastuse = jiffies;
46	bstats_update(&d->tcf_bstats, skb);
47
48	/* print policy string followed by _ then packet count
49	 * Example if this was the 3rd packet and the string was "hello"
50	 * then it would look like "hello_3" (without quotes)
51	 */
52	pr_info("simple: %s_%d\n",
53	       (char *)d->tcfd_defdata, d->tcf_bstats.packets);
54	spin_unlock(&d->tcf_lock);
55	return d->tcf_action;
56}
57
58static int tcf_simp_release(struct tcf_defact *d, int bind)
59{
60	int ret = 0;
61	if (d) {
62		if (bind)
63			d->tcf_bindcnt--;
64		d->tcf_refcnt--;
65		if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
66			kfree(d->tcfd_defdata);
67			tcf_hash_destroy(&d->common, &simp_hash_info);
68			ret = 1;
69		}
70	}
71	return ret;
72}
73
74static int alloc_defdata(struct tcf_defact *d, char *defdata)
75{
76	d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
77	if (unlikely(!d->tcfd_defdata))
78		return -ENOMEM;
79	strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
80	return 0;
81}
82
83static void reset_policy(struct tcf_defact *d, char *defdata,
84			 struct tc_defact *p)
85{
86	spin_lock_bh(&d->tcf_lock);
87	d->tcf_action = p->action;
88	memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
89	strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
90	spin_unlock_bh(&d->tcf_lock);
91}
92
93static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
94	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },
95	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },
96};
97
98static int tcf_simp_init(struct net *net, struct nlattr *nla,
99			 struct nlattr *est, struct tc_action *a,
100			 int ovr, int bind)
101{
102	struct nlattr *tb[TCA_DEF_MAX + 1];
103	struct tc_defact *parm;
104	struct tcf_defact *d;
105	struct tcf_common *pc;
106	char *defdata;
107	int ret = 0, err;
108
109	if (nla == NULL)
110		return -EINVAL;
111
112	err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
113	if (err < 0)
114		return err;
115
116	if (tb[TCA_DEF_PARMS] == NULL)
117		return -EINVAL;
118
119	if (tb[TCA_DEF_DATA] == NULL)
120		return -EINVAL;
121
122	parm = nla_data(tb[TCA_DEF_PARMS]);
123	defdata = nla_data(tb[TCA_DEF_DATA]);
124
125	pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
126	if (!pc) {
127		pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
128				     &simp_idx_gen, &simp_hash_info);
129		if (IS_ERR(pc))
130			return PTR_ERR(pc);
131
132		d = to_defact(pc);
133		ret = alloc_defdata(d, defdata);
134		if (ret < 0) {
135			if (est)
136				gen_kill_estimator(&pc->tcfc_bstats,
137						   &pc->tcfc_rate_est);
138			kfree_rcu(pc, tcfc_rcu);
139			return ret;
140		}
141		d->tcf_action = parm->action;
142		ret = ACT_P_CREATED;
143	} else {
144		d = to_defact(pc);
145		if (!ovr) {
146			tcf_simp_release(d, bind);
147			return -EEXIST;
148		}
149		reset_policy(d, defdata, parm);
150	}
151
152	if (ret == ACT_P_CREATED)
153		tcf_hash_insert(pc, &simp_hash_info);
154	return ret;
155}
156
157static int tcf_simp_cleanup(struct tc_action *a, int bind)
158{
159	struct tcf_defact *d = a->priv;
160
161	if (d)
162		return tcf_simp_release(d, bind);
163	return 0;
164}
165
166static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
167			 int bind, int ref)
168{
169	unsigned char *b = skb_tail_pointer(skb);
170	struct tcf_defact *d = a->priv;
171	struct tc_defact opt = {
172		.index   = d->tcf_index,
173		.refcnt  = d->tcf_refcnt - ref,
174		.bindcnt = d->tcf_bindcnt - bind,
175		.action  = d->tcf_action,
176	};
177	struct tcf_t t;
178
179	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
180	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
181		goto nla_put_failure;
182	t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
183	t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
184	t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
185	if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
186		goto nla_put_failure;
187	return skb->len;
188
189nla_put_failure:
190	nlmsg_trim(skb, b);
191	return -1;
192}
193
194static struct tc_action_ops act_simp_ops = {
195	.kind		=	"simple",
196	.hinfo		=	&simp_hash_info,
197	.type		=	TCA_ACT_SIMP,
198	.capab		=	TCA_CAP_NONE,
199	.owner		=	THIS_MODULE,
200	.act		=	tcf_simp,
201	.dump		=	tcf_simp_dump,
202	.cleanup	=	tcf_simp_cleanup,
203	.init		=	tcf_simp_init,
204	.walk		=	tcf_generic_walker,
205};
206
207MODULE_AUTHOR("Jamal Hadi Salim(2005)");
208MODULE_DESCRIPTION("Simple example action");
209MODULE_LICENSE("GPL");
210
211static int __init simp_init_module(void)
212{
213	int ret = tcf_register_action(&act_simp_ops);
214	if (!ret)
215		pr_info("Simple TC action Loaded\n");
216	return ret;
217}
218
219static void __exit simp_cleanup_module(void)
220{
221	tcf_unregister_action(&act_simp_ops);
222}
223
224module_init(simp_init_module);
225module_exit(simp_cleanup_module);
226