xref: /openbmc/linux/net/sched/act_gact.c (revision 68198dca)
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)
60 {
61 	struct tc_action_net *tn = net_generic(net, gact_net_id);
62 	struct nlattr *tb[TCA_GACT_MAX + 1];
63 	struct tc_gact *parm;
64 	struct tcf_gact *gact;
65 	int ret = 0;
66 	int err;
67 #ifdef CONFIG_GACT_PROB
68 	struct tc_gact_p *p_parm = NULL;
69 #endif
70 
71 	if (nla == NULL)
72 		return -EINVAL;
73 
74 	err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy, NULL);
75 	if (err < 0)
76 		return err;
77 
78 	if (tb[TCA_GACT_PARMS] == NULL)
79 		return -EINVAL;
80 	parm = nla_data(tb[TCA_GACT_PARMS]);
81 
82 #ifndef CONFIG_GACT_PROB
83 	if (tb[TCA_GACT_PROB] != NULL)
84 		return -EOPNOTSUPP;
85 #else
86 	if (tb[TCA_GACT_PROB]) {
87 		p_parm = nla_data(tb[TCA_GACT_PROB]);
88 		if (p_parm->ptype >= MAX_RAND)
89 			return -EINVAL;
90 	}
91 #endif
92 
93 	if (!tcf_idr_check(tn, parm->index, a, bind)) {
94 		ret = tcf_idr_create(tn, parm->index, est, a,
95 				     &act_gact_ops, bind, true);
96 		if (ret)
97 			return ret;
98 		ret = ACT_P_CREATED;
99 	} else {
100 		if (bind)/* dont override defaults */
101 			return 0;
102 		tcf_idr_release(*a, bind);
103 		if (!ovr)
104 			return -EEXIST;
105 	}
106 
107 	gact = to_gact(*a);
108 
109 	ASSERT_RTNL();
110 	gact->tcf_action = parm->action;
111 #ifdef CONFIG_GACT_PROB
112 	if (p_parm) {
113 		gact->tcfg_paction = p_parm->paction;
114 		gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
115 		/* Make sure tcfg_pval is written before tcfg_ptype
116 		 * coupled with smp_rmb() in gact_net_rand() & gact_determ()
117 		 */
118 		smp_wmb();
119 		gact->tcfg_ptype   = p_parm->ptype;
120 	}
121 #endif
122 	if (ret == ACT_P_CREATED)
123 		tcf_idr_insert(tn, *a);
124 	return ret;
125 }
126 
127 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
128 		    struct tcf_result *res)
129 {
130 	struct tcf_gact *gact = to_gact(a);
131 	int action = READ_ONCE(gact->tcf_action);
132 
133 #ifdef CONFIG_GACT_PROB
134 	{
135 	u32 ptype = READ_ONCE(gact->tcfg_ptype);
136 
137 	if (ptype)
138 		action = gact_rand[ptype](gact);
139 	}
140 #endif
141 	bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
142 	if (action == TC_ACT_SHOT)
143 		qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
144 
145 	tcf_lastuse_update(&gact->tcf_tm);
146 
147 	return action;
148 }
149 
150 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
151 				  u64 lastuse)
152 {
153 	struct tcf_gact *gact = to_gact(a);
154 	int action = READ_ONCE(gact->tcf_action);
155 	struct tcf_t *tm = &gact->tcf_tm;
156 
157 	_bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
158 			   packets);
159 	if (action == TC_ACT_SHOT)
160 		this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
161 
162 	tm->lastuse = lastuse;
163 }
164 
165 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
166 			 int bind, int ref)
167 {
168 	unsigned char *b = skb_tail_pointer(skb);
169 	struct tcf_gact *gact = to_gact(a);
170 	struct tc_gact opt = {
171 		.index   = gact->tcf_index,
172 		.refcnt  = gact->tcf_refcnt - ref,
173 		.bindcnt = gact->tcf_bindcnt - bind,
174 		.action  = gact->tcf_action,
175 	};
176 	struct tcf_t t;
177 
178 	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
179 		goto nla_put_failure;
180 #ifdef CONFIG_GACT_PROB
181 	if (gact->tcfg_ptype) {
182 		struct tc_gact_p p_opt = {
183 			.paction = gact->tcfg_paction,
184 			.pval    = gact->tcfg_pval,
185 			.ptype   = gact->tcfg_ptype,
186 		};
187 
188 		if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
189 			goto nla_put_failure;
190 	}
191 #endif
192 	tcf_tm_dump(&t, &gact->tcf_tm);
193 	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
194 		goto nla_put_failure;
195 	return skb->len;
196 
197 nla_put_failure:
198 	nlmsg_trim(skb, b);
199 	return -1;
200 }
201 
202 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
203 			   struct netlink_callback *cb, int type,
204 			   const struct tc_action_ops *ops)
205 {
206 	struct tc_action_net *tn = net_generic(net, gact_net_id);
207 
208 	return tcf_generic_walker(tn, skb, cb, type, ops);
209 }
210 
211 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
212 {
213 	struct tc_action_net *tn = net_generic(net, gact_net_id);
214 
215 	return tcf_idr_search(tn, a, index);
216 }
217 
218 static struct tc_action_ops act_gact_ops = {
219 	.kind		=	"gact",
220 	.type		=	TCA_ACT_GACT,
221 	.owner		=	THIS_MODULE,
222 	.act		=	tcf_gact,
223 	.stats_update	=	tcf_gact_stats_update,
224 	.dump		=	tcf_gact_dump,
225 	.init		=	tcf_gact_init,
226 	.walk		=	tcf_gact_walker,
227 	.lookup		=	tcf_gact_search,
228 	.size		=	sizeof(struct tcf_gact),
229 };
230 
231 static __net_init int gact_init_net(struct net *net)
232 {
233 	struct tc_action_net *tn = net_generic(net, gact_net_id);
234 
235 	return tc_action_net_init(tn, &act_gact_ops);
236 }
237 
238 static void __net_exit gact_exit_net(struct net *net)
239 {
240 	struct tc_action_net *tn = net_generic(net, gact_net_id);
241 
242 	tc_action_net_exit(tn);
243 }
244 
245 static struct pernet_operations gact_net_ops = {
246 	.init = gact_init_net,
247 	.exit = gact_exit_net,
248 	.id   = &gact_net_id,
249 	.size = sizeof(struct tc_action_net),
250 };
251 
252 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
253 MODULE_DESCRIPTION("Generic Classifier actions");
254 MODULE_LICENSE("GPL");
255 
256 static int __init gact_init_module(void)
257 {
258 #ifdef CONFIG_GACT_PROB
259 	pr_info("GACT probability on\n");
260 #else
261 	pr_info("GACT probability NOT on\n");
262 #endif
263 
264 	return tcf_register_action(&act_gact_ops, &gact_net_ops);
265 }
266 
267 static void __exit gact_cleanup_module(void)
268 {
269 	tcf_unregister_action(&act_gact_ops, &gact_net_ops);
270 }
271 
272 module_init(gact_init_module);
273 module_exit(gact_cleanup_module);
274