b61c20ebb314ac8301f66758c6de0d97e38c7a9a
[muen/linux.git] / net / sched / act_gact.c
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         .type           =       TCA_ACT_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);