xref: /linux/net/sched/act_gact.c (revision b60a5b8dcf49af9f2c60ae82e0383ee8e62a9a52)
1 /*
2  * net/sched/act_gact.c		Generic actions
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  * copyright 	Jamal Hadi Salim (2002-4)
10  *
11  */
12 
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/skbuff.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23 #include <linux/tc_act/tc_gact.h>
24 #include <net/tc_act/tc_gact.h>
25 
26 static unsigned int gact_net_id;
27 static struct tc_action_ops act_gact_ops;
28 
29 #ifdef CONFIG_GACT_PROB
30 static int gact_net_rand(struct tcf_gact *gact)
31 {
32 	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
33 	if (prandom_u32() % gact->tcfg_pval)
34 		return gact->tcf_action;
35 	return gact->tcfg_paction;
36 }
37 
38 static int gact_determ(struct tcf_gact *gact)
39 {
40 	u32 pack = atomic_inc_return(&gact->packets);
41 
42 	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
43 	if (pack % gact->tcfg_pval)
44 		return gact->tcf_action;
45 	return gact->tcfg_paction;
46 }
47 
48 typedef int (*g_rand)(struct tcf_gact *gact);
49 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
50 #endif /* CONFIG_GACT_PROB */
51 
52 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
53 	[TCA_GACT_PARMS]	= { .len = sizeof(struct tc_gact) },
54 	[TCA_GACT_PROB]		= { .len = sizeof(struct tc_gact_p) },
55 };
56 
57 static int tcf_gact_init(struct net *net, struct nlattr *nla,
58 			 struct nlattr *est, struct tc_action **a,
59 			 int ovr, int bind, bool rtnl_held,
60 			 struct netlink_ext_ack *extack)
61 {
62 	struct tc_action_net *tn = net_generic(net, gact_net_id);
63 	struct nlattr *tb[TCA_GACT_MAX + 1];
64 	struct tc_gact *parm;
65 	struct tcf_gact *gact;
66 	int ret = 0;
67 	int err;
68 #ifdef CONFIG_GACT_PROB
69 	struct tc_gact_p *p_parm = NULL;
70 #endif
71 
72 	if (nla == NULL)
73 		return -EINVAL;
74 
75 	err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy, NULL);
76 	if (err < 0)
77 		return err;
78 
79 	if (tb[TCA_GACT_PARMS] == NULL)
80 		return -EINVAL;
81 	parm = nla_data(tb[TCA_GACT_PARMS]);
82 
83 #ifndef CONFIG_GACT_PROB
84 	if (tb[TCA_GACT_PROB] != NULL)
85 		return -EOPNOTSUPP;
86 #else
87 	if (tb[TCA_GACT_PROB]) {
88 		p_parm = nla_data(tb[TCA_GACT_PROB]);
89 		if (p_parm->ptype >= MAX_RAND)
90 			return -EINVAL;
91 		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
92 			NL_SET_ERR_MSG(extack,
93 				       "goto chain not allowed on fallback");
94 			return -EINVAL;
95 		}
96 	}
97 #endif
98 
99 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
100 	if (!err) {
101 		ret = tcf_idr_create(tn, parm->index, est, a,
102 				     &act_gact_ops, bind, true);
103 		if (ret) {
104 			tcf_idr_cleanup(tn, parm->index);
105 			return ret;
106 		}
107 		ret = ACT_P_CREATED;
108 	} else if (err > 0) {
109 		if (bind)/* dont override defaults */
110 			return 0;
111 		if (!ovr) {
112 			tcf_idr_release(*a, bind);
113 			return -EEXIST;
114 		}
115 	} else {
116 		return err;
117 	}
118 
119 	gact = to_gact(*a);
120 
121 	spin_lock_bh(&gact->tcf_lock);
122 	gact->tcf_action = parm->action;
123 #ifdef CONFIG_GACT_PROB
124 	if (p_parm) {
125 		gact->tcfg_paction = p_parm->paction;
126 		gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
127 		/* Make sure tcfg_pval is written before tcfg_ptype
128 		 * coupled with smp_rmb() in gact_net_rand() & gact_determ()
129 		 */
130 		smp_wmb();
131 		gact->tcfg_ptype   = p_parm->ptype;
132 	}
133 #endif
134 	spin_unlock_bh(&gact->tcf_lock);
135 
136 	if (ret == ACT_P_CREATED)
137 		tcf_idr_insert(tn, *a);
138 	return ret;
139 }
140 
141 static int tcf_gact_act(struct sk_buff *skb, const struct tc_action *a,
142 			struct tcf_result *res)
143 {
144 	struct tcf_gact *gact = to_gact(a);
145 	int action = READ_ONCE(gact->tcf_action);
146 
147 #ifdef CONFIG_GACT_PROB
148 	{
149 	u32 ptype = READ_ONCE(gact->tcfg_ptype);
150 
151 	if (ptype)
152 		action = gact_rand[ptype](gact);
153 	}
154 #endif
155 	bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
156 	if (action == TC_ACT_SHOT)
157 		qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
158 
159 	tcf_lastuse_update(&gact->tcf_tm);
160 
161 	return action;
162 }
163 
164 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
165 				  u64 lastuse, bool hw)
166 {
167 	struct tcf_gact *gact = to_gact(a);
168 	int action = READ_ONCE(gact->tcf_action);
169 	struct tcf_t *tm = &gact->tcf_tm;
170 
171 	_bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
172 			   packets);
173 	if (action == TC_ACT_SHOT)
174 		this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
175 
176 	if (hw)
177 		_bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats_hw),
178 				   bytes, packets);
179 
180 	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
181 }
182 
183 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
184 			 int bind, int ref)
185 {
186 	unsigned char *b = skb_tail_pointer(skb);
187 	struct tcf_gact *gact = to_gact(a);
188 	struct tc_gact opt = {
189 		.index   = gact->tcf_index,
190 		.refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
191 		.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
192 	};
193 	struct tcf_t t;
194 
195 	spin_lock_bh(&gact->tcf_lock);
196 	opt.action = gact->tcf_action;
197 	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
198 		goto nla_put_failure;
199 #ifdef CONFIG_GACT_PROB
200 	if (gact->tcfg_ptype) {
201 		struct tc_gact_p p_opt = {
202 			.paction = gact->tcfg_paction,
203 			.pval    = gact->tcfg_pval,
204 			.ptype   = gact->tcfg_ptype,
205 		};
206 
207 		if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
208 			goto nla_put_failure;
209 	}
210 #endif
211 	tcf_tm_dump(&t, &gact->tcf_tm);
212 	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
213 		goto nla_put_failure;
214 	spin_unlock_bh(&gact->tcf_lock);
215 
216 	return skb->len;
217 
218 nla_put_failure:
219 	spin_unlock_bh(&gact->tcf_lock);
220 	nlmsg_trim(skb, b);
221 	return -1;
222 }
223 
224 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
225 			   struct netlink_callback *cb, int type,
226 			   const struct tc_action_ops *ops,
227 			   struct netlink_ext_ack *extack)
228 {
229 	struct tc_action_net *tn = net_generic(net, gact_net_id);
230 
231 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
232 }
233 
234 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
235 {
236 	struct tc_action_net *tn = net_generic(net, gact_net_id);
237 
238 	return tcf_idr_search(tn, a, index);
239 }
240 
241 static size_t tcf_gact_get_fill_size(const struct tc_action *act)
242 {
243 	size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
244 
245 #ifdef CONFIG_GACT_PROB
246 	if (to_gact(act)->tcfg_ptype)
247 		/* TCA_GACT_PROB */
248 		sz += nla_total_size(sizeof(struct tc_gact_p));
249 #endif
250 
251 	return sz;
252 }
253 
254 static struct tc_action_ops act_gact_ops = {
255 	.kind		=	"gact",
256 	.id		=	TCA_ID_GACT,
257 	.owner		=	THIS_MODULE,
258 	.act		=	tcf_gact_act,
259 	.stats_update	=	tcf_gact_stats_update,
260 	.dump		=	tcf_gact_dump,
261 	.init		=	tcf_gact_init,
262 	.walk		=	tcf_gact_walker,
263 	.lookup		=	tcf_gact_search,
264 	.get_fill_size	=	tcf_gact_get_fill_size,
265 	.size		=	sizeof(struct tcf_gact),
266 };
267 
268 static __net_init int gact_init_net(struct net *net)
269 {
270 	struct tc_action_net *tn = net_generic(net, gact_net_id);
271 
272 	return tc_action_net_init(tn, &act_gact_ops);
273 }
274 
275 static void __net_exit gact_exit_net(struct list_head *net_list)
276 {
277 	tc_action_net_exit(net_list, gact_net_id);
278 }
279 
280 static struct pernet_operations gact_net_ops = {
281 	.init = gact_init_net,
282 	.exit_batch = gact_exit_net,
283 	.id   = &gact_net_id,
284 	.size = sizeof(struct tc_action_net),
285 };
286 
287 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
288 MODULE_DESCRIPTION("Generic Classifier actions");
289 MODULE_LICENSE("GPL");
290 
291 static int __init gact_init_module(void)
292 {
293 #ifdef CONFIG_GACT_PROB
294 	pr_info("GACT probability on\n");
295 #else
296 	pr_info("GACT probability NOT on\n");
297 #endif
298 
299 	return tcf_register_action(&act_gact_ops, &gact_net_ops);
300 }
301 
302 static void __exit gact_cleanup_module(void)
303 {
304 	tcf_unregister_action(&act_gact_ops, &gact_net_ops);
305 }
306 
307 module_init(gact_init_module);
308 module_exit(gact_cleanup_module);
309