xref: /openbmc/linux/net/sched/act_simple.c (revision 871cf386)
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 
22 static struct tc_action_ops act_simp_ops;
23 
24 #define SIMP_MAX_DATA	32
tcf_simp_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)25 TC_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 
tcf_simp_release(struct tc_action * a)46 static void tcf_simp_release(struct tc_action *a)
47 {
48 	struct tcf_defact *d = to_defact(a);
49 	kfree(d->tcfd_defdata);
50 }
51 
alloc_defdata(struct tcf_defact * d,const struct nlattr * defdata)52 static 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 
reset_policy(struct tc_action * a,const struct nlattr * defdata,struct tc_defact * p,struct tcf_proto * tp,struct netlink_ext_ack * extack)61 static 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 
83 static 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 
tcf_simp_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,struct tcf_proto * tp,u32 flags,struct netlink_ext_ack * extack)88 static 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 0;
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;
163 put_chain:
164 	if (goto_ch)
165 		tcf_chain_put_by_act(goto_ch);
166 release_idr:
167 	tcf_idr_release(*a, bind);
168 	return err;
169 }
170 
tcf_simp_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)171 static 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 
196 nla_put_failure:
197 	spin_unlock_bh(&d->tcf_lock);
198 	nlmsg_trim(skb, b);
199 	return -1;
200 }
201 
202 static 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 };
212 
simp_init_net(struct net * net)213 static __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 
simp_exit_net(struct list_head * net_list)220 static 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 
225 static 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 
232 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
233 MODULE_DESCRIPTION("Simple example action");
234 MODULE_LICENSE("GPL");
235 
simp_init_module(void)236 static 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 
simp_cleanup_module(void)244 static void __exit simp_cleanup_module(void)
245 {
246 	tcf_unregister_action(&act_simp_ops, &simp_net_ops);
247 }
248 
249 module_init(simp_init_module);
250 module_exit(simp_cleanup_module);
251