xref: /openbmc/linux/net/sched/act_simple.c (revision 22246614)
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/init.h>
15 #include <linux/kernel.h>
16 #include <linux/skbuff.h>
17 #include <linux/rtnetlink.h>
18 #include <net/netlink.h>
19 #include <net/pkt_sched.h>
20 
21 #define TCA_ACT_SIMP 22
22 
23 #include <linux/tc_act/tc_defact.h>
24 #include <net/tc_act/tc_defact.h>
25 
26 #define SIMP_TAB_MASK     7
27 static struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
28 static u32 simp_idx_gen;
29 static DEFINE_RWLOCK(simp_lock);
30 
31 static struct tcf_hashinfo simp_hash_info = {
32 	.htab	=	tcf_simp_ht,
33 	.hmask	=	SIMP_TAB_MASK,
34 	.lock	=	&simp_lock,
35 };
36 
37 #define SIMP_MAX_DATA	32
38 static int tcf_simp(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
39 {
40 	struct tcf_defact *d = a->priv;
41 
42 	spin_lock(&d->tcf_lock);
43 	d->tcf_tm.lastuse = jiffies;
44 	d->tcf_bstats.bytes += skb->len;
45 	d->tcf_bstats.packets++;
46 
47 	/* print policy string followed by _ then packet count
48 	 * Example if this was the 3rd packet and the string was "hello"
49 	 * then it would look like "hello_3" (without quotes)
50 	 **/
51 	printk("simple: %s_%d\n",
52 	       (char *)d->tcfd_defdata, d->tcf_bstats.packets);
53 	spin_unlock(&d->tcf_lock);
54 	return d->tcf_action;
55 }
56 
57 static int tcf_simp_release(struct tcf_defact *d, int bind)
58 {
59 	int ret = 0;
60 	if (d) {
61 		if (bind)
62 			d->tcf_bindcnt--;
63 		d->tcf_refcnt--;
64 		if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
65 			kfree(d->tcfd_defdata);
66 			tcf_hash_destroy(&d->common, &simp_hash_info);
67 			ret = 1;
68 		}
69 	}
70 	return ret;
71 }
72 
73 static int alloc_defdata(struct tcf_defact *d, char *defdata)
74 {
75 	d->tcfd_defdata = kstrndup(defdata, SIMP_MAX_DATA, GFP_KERNEL);
76 	if (unlikely(!d->tcfd_defdata))
77 		return -ENOMEM;
78 
79 	return 0;
80 }
81 
82 static void reset_policy(struct tcf_defact *d, char *defdata,
83 			 struct tc_defact *p)
84 {
85 	spin_lock_bh(&d->tcf_lock);
86 	d->tcf_action = p->action;
87 	memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
88 	strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
89 	spin_unlock_bh(&d->tcf_lock);
90 }
91 
92 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
93 	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },
94 	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },
95 };
96 
97 static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,
98 			 struct tc_action *a, int ovr, int bind)
99 {
100 	struct nlattr *tb[TCA_DEF_MAX + 1];
101 	struct tc_defact *parm;
102 	struct tcf_defact *d;
103 	struct tcf_common *pc;
104 	char *defdata;
105 	int ret = 0, err;
106 
107 	if (nla == NULL)
108 		return -EINVAL;
109 
110 	err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
111 	if (err < 0)
112 		return err;
113 
114 	if (tb[TCA_DEF_PARMS] == NULL)
115 		return -EINVAL;
116 
117 	if (tb[TCA_DEF_DATA] == NULL)
118 		return -EINVAL;
119 
120 	parm = nla_data(tb[TCA_DEF_PARMS]);
121 	defdata = nla_data(tb[TCA_DEF_DATA]);
122 
123 	pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
124 	if (!pc) {
125 		pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
126 				     &simp_idx_gen, &simp_hash_info);
127 		if (unlikely(!pc))
128 			return -ENOMEM;
129 
130 		d = to_defact(pc);
131 		ret = alloc_defdata(d, defdata);
132 		if (ret < 0) {
133 			kfree(pc);
134 			return ret;
135 		}
136 		d->tcf_action = parm->action;
137 		ret = ACT_P_CREATED;
138 	} else {
139 		d = to_defact(pc);
140 		if (!ovr) {
141 			tcf_simp_release(d, bind);
142 			return -EEXIST;
143 		}
144 		reset_policy(d, defdata, parm);
145 	}
146 
147 	if (ret == ACT_P_CREATED)
148 		tcf_hash_insert(pc, &simp_hash_info);
149 	return ret;
150 }
151 
152 static inline int tcf_simp_cleanup(struct tc_action *a, int bind)
153 {
154 	struct tcf_defact *d = a->priv;
155 
156 	if (d)
157 		return tcf_simp_release(d, bind);
158 	return 0;
159 }
160 
161 static inline int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
162 				int bind, int ref)
163 {
164 	unsigned char *b = skb_tail_pointer(skb);
165 	struct tcf_defact *d = a->priv;
166 	struct tc_defact opt;
167 	struct tcf_t t;
168 
169 	opt.index = d->tcf_index;
170 	opt.refcnt = d->tcf_refcnt - ref;
171 	opt.bindcnt = d->tcf_bindcnt - bind;
172 	opt.action = d->tcf_action;
173 	NLA_PUT(skb, TCA_DEF_PARMS, sizeof(opt), &opt);
174 	NLA_PUT_STRING(skb, TCA_DEF_DATA, d->tcfd_defdata);
175 	t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
176 	t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
177 	t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
178 	NLA_PUT(skb, TCA_DEF_TM, sizeof(t), &t);
179 	return skb->len;
180 
181 nla_put_failure:
182 	nlmsg_trim(skb, b);
183 	return -1;
184 }
185 
186 static struct tc_action_ops act_simp_ops = {
187 	.kind		=	"simple",
188 	.hinfo		=	&simp_hash_info,
189 	.type		=	TCA_ACT_SIMP,
190 	.capab		=	TCA_CAP_NONE,
191 	.owner		=	THIS_MODULE,
192 	.act		=	tcf_simp,
193 	.dump		=	tcf_simp_dump,
194 	.cleanup	=	tcf_simp_cleanup,
195 	.init		=	tcf_simp_init,
196 	.walk		=	tcf_generic_walker,
197 };
198 
199 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
200 MODULE_DESCRIPTION("Simple example action");
201 MODULE_LICENSE("GPL");
202 
203 static int __init simp_init_module(void)
204 {
205 	int ret = tcf_register_action(&act_simp_ops);
206 	if (!ret)
207 		printk("Simple TC action Loaded\n");
208 	return ret;
209 }
210 
211 static void __exit simp_cleanup_module(void)
212 {
213 	tcf_unregister_action(&act_simp_ops);
214 }
215 
216 module_init(simp_init_module);
217 module_exit(simp_cleanup_module);
218