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 #define GACT_TAB_MASK   15
  27
  28 static int gact_net_id;
  29
  30 #ifdef CONFIG_GACT_PROB
  31 static int gact_net_rand(struct tcf_gact *gact)
  32 {
  33         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  34         if (prandom_u32() % gact->tcfg_pval)
  35                 return gact->tcf_action;
  36         return gact->tcfg_paction;
  37 }
  38
  39 static int gact_determ(struct tcf_gact *gact)
  40 {
  41         u32 pack = atomic_inc_return(&gact->packets);
  42
  43         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  44         if (pack % gact->tcfg_pval)
  45                 return gact->tcf_action;
  46         return gact->tcfg_paction;
  47 }
  48
  49 typedef int (*g_rand)(struct tcf_gact *gact);
  50 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  51 #endif /* CONFIG_GACT_PROB */
  52
  53 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  54         [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  55         [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  56 };
  57
  58 static int tcf_gact_init(struct net *net, struct nlattr *nla,
  59                          struct nlattr *est, struct tc_action *a,
  60                          int ovr, int bind)
  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);
  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         }
  92 #endif
  93
  94         if (!tcf_hash_check(tn, parm->index, a, bind)) {
  95                 ret = tcf_hash_create(tn, parm->index, est, a,
  96                                       sizeof(*gact), bind, true);
  97                 if (ret)
  98                         return ret;
  99                 ret = ACT_P_CREATED;
 100         } else {
 101                 if (bind)/* dont override defaults */
 102                         return 0;
 103                 tcf_hash_release(a, bind);
 104                 if (!ovr)
 105                         return -EEXIST;
 106         }
 107
 108         gact = to_gact(a);
 109
 110         ASSERT_RTNL();
 111         gact->tcf_action = parm->action;
 112 #ifdef CONFIG_GACT_PROB
 113         if (p_parm) {
 114                 gact->tcfg_paction = p_parm->paction;
 115                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 116                 /* Make sure tcfg_pval is written before tcfg_ptype
 117                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 118                  */
 119                 smp_wmb();
 120                 gact->tcfg_ptype   = p_parm->ptype;
 121         }
 122 #endif
 123         if (ret == ACT_P_CREATED)
 124                 tcf_hash_insert(tn, a);
 125         return ret;
 126 }
 127
 128 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
 129                     struct tcf_result *res)
 130 {
 131         struct tcf_gact *gact = a->priv;
 132         int action = READ_ONCE(gact->tcf_action);
 133
 134 #ifdef CONFIG_GACT_PROB
 135         {
 136         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 137
 138         if (ptype)
 139                 action = gact_rand[ptype](gact);
 140         }
 141 #endif
 142         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 143         if (action == TC_ACT_SHOT)
 144                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 145
 146         tcf_lastuse_update(&gact->tcf_tm);
 147
 148         return action;
 149 }
 150
 151 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 152 {
 153         unsigned char *b = skb_tail_pointer(skb);
 154         struct tcf_gact *gact = a->priv;
 155         struct tc_gact opt = {
 156                 .index   = gact->tcf_index,
 157                 .refcnt  = gact->tcf_refcnt - ref,
 158                 .bindcnt = gact->tcf_bindcnt - bind,
 159                 .action  = gact->tcf_action,
 160         };
 161         struct tcf_t t;
 162
 163         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 164                 goto nla_put_failure;
 165 #ifdef CONFIG_GACT_PROB
 166         if (gact->tcfg_ptype) {
 167                 struct tc_gact_p p_opt = {
 168                         .paction = gact->tcfg_paction,
 169                         .pval    = gact->tcfg_pval,
 170                         .ptype   = gact->tcfg_ptype,
 171                 };
 172
 173                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 174                         goto nla_put_failure;
 175         }
 176 #endif
 177         t.install = jiffies_to_clock_t(jiffies - gact->tcf_tm.install);
 178         t.lastuse = jiffies_to_clock_t(jiffies - gact->tcf_tm.lastuse);
 179         t.expires = jiffies_to_clock_t(gact->tcf_tm.expires);
 180         if (nla_put(skb, TCA_GACT_TM, sizeof(t), &t))
 181                 goto nla_put_failure;
 182         return skb->len;
 183
 184 nla_put_failure:
 185         nlmsg_trim(skb, b);
 186         return -1;
 187 }
 188
 189 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 190                            struct netlink_callback *cb, int type,
 191                            struct tc_action *a)
 192 {
 193         struct tc_action_net *tn = net_generic(net, gact_net_id);
 194
 195         return tcf_generic_walker(tn, skb, cb, type, a);
 196 }
 197
 198 static int tcf_gact_search(struct net *net, struct tc_action *a, u32 index)
 199 {
 200         struct tc_action_net *tn = net_generic(net, gact_net_id);
 201
 202         return tcf_hash_search(tn, a, index);
 203 }
 204
 205 static struct tc_action_ops act_gact_ops = {
 206         .kind           =       "gact",
 207         .type           =       TCA_ACT_GACT,
 208         .owner          =       THIS_MODULE,
 209         .act            =       tcf_gact,
 210         .dump           =       tcf_gact_dump,
 211         .init           =       tcf_gact_init,
 212         .walk           =       tcf_gact_walker,
 213         .lookup         =       tcf_gact_search,
 214 };
 215
 216 static __net_init int gact_init_net(struct net *net)
 217 {
 218         struct tc_action_net *tn = net_generic(net, gact_net_id);
 219
 220         return tc_action_net_init(tn, &act_gact_ops, GACT_TAB_MASK);
 221 }
 222
 223 static void __net_exit gact_exit_net(struct net *net)
 224 {
 225         struct tc_action_net *tn = net_generic(net, gact_net_id);
 226
 227         tc_action_net_exit(tn);
 228 }
 229
 230 static struct pernet_operations gact_net_ops = {
 231         .init = gact_init_net,
 232         .exit = gact_exit_net,
 233         .id   = &gact_net_id,
 234         .size = sizeof(struct tc_action_net),
 235 };
 236
 237 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 238 MODULE_DESCRIPTION("Generic Classifier actions");
 239 MODULE_LICENSE("GPL");
 240
 241 static int __init gact_init_module(void)
 242 {
 243 #ifdef CONFIG_GACT_PROB
 244         pr_info("GACT probability on\n");
 245 #else
 246         pr_info("GACT probability NOT on\n");
 247 #endif
 248
 249         return tcf_register_action(&act_gact_ops, &gact_net_ops);
 250 }
 251
 252 static void __exit gact_cleanup_module(void)
 253 {
 254         tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 255 }
 256
 257 module_init(gact_init_module);
 258 module_exit(gact_cleanup_module);