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 #ifdef CONFIG_GACT_PROB
  29 static int gact_net_rand(struct tcf_gact *gact)
  30 {
  31         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  32         if (prandom_u32() % gact->tcfg_pval)
  33                 return gact->tcf_action;
  34         return gact->tcfg_paction;
  35 }
  36
  37 static int gact_determ(struct tcf_gact *gact)
  38 {
  39         u32 pack = atomic_inc_return(&gact->packets);
  40
  41         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  42         if (pack % gact->tcfg_pval)
  43                 return gact->tcf_action;
  44         return gact->tcfg_paction;
  45 }
  46
  47 typedef int (*g_rand)(struct tcf_gact *gact);
  48 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  49 #endif /* CONFIG_GACT_PROB */
  50
  51 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  52         [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  53         [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  54 };
  55
  56 static int tcf_gact_init(struct net *net, struct nlattr *nla,
  57                          struct nlattr *est, struct tc_action *a,
  58                          int ovr, int bind)
  59 {
  60         struct nlattr *tb[TCA_GACT_MAX + 1];
  61         struct tc_gact *parm;
  62         struct tcf_gact *gact;
  63         int ret = 0;
  64         int err;
  65 #ifdef CONFIG_GACT_PROB
  66         struct tc_gact_p *p_parm = NULL;
  67 #endif
  68
  69         if (nla == NULL)
  70                 return -EINVAL;
  71
  72         err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy);
  73         if (err < 0)
  74                 return err;
  75
  76         if (tb[TCA_GACT_PARMS] == NULL)
  77                 return -EINVAL;
  78         parm = nla_data(tb[TCA_GACT_PARMS]);
  79
  80 #ifndef CONFIG_GACT_PROB
  81         if (tb[TCA_GACT_PROB] != NULL)
  82                 return -EOPNOTSUPP;
  83 #else
  84         if (tb[TCA_GACT_PROB]) {
  85                 p_parm = nla_data(tb[TCA_GACT_PROB]);
  86                 if (p_parm->ptype >= MAX_RAND)
  87                         return -EINVAL;
  88         }
  89 #endif
  90
  91         if (!tcf_hash_check(parm->index, a, bind)) {
  92                 ret = tcf_hash_create(parm->index, est, a, sizeof(*gact),
  93                                       bind, true);
  94                 if (ret)
  95                         return ret;
  96                 ret = ACT_P_CREATED;
  97         } else {
  98                 if (bind)/* dont override defaults */
  99                         return 0;
 100                 tcf_hash_release(a, bind);
 101                 if (!ovr)
 102                         return -EEXIST;
 103         }
 104
 105         gact = to_gact(a);
 106
 107         ASSERT_RTNL();
 108         gact->tcf_action = parm->action;
 109 #ifdef CONFIG_GACT_PROB
 110         if (p_parm) {
 111                 gact->tcfg_paction = p_parm->paction;
 112                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 113                 /* Make sure tcfg_pval is written before tcfg_ptype
 114                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 115                  */
 116                 smp_wmb();
 117                 gact->tcfg_ptype   = p_parm->ptype;
 118         }
 119 #endif
 120         if (ret == ACT_P_CREATED)
 121                 tcf_hash_insert(a);
 122         return ret;
 123 }
 124
 125 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
 126                     struct tcf_result *res)
 127 {
 128         struct tcf_gact *gact = a->priv;
 129         int action = READ_ONCE(gact->tcf_action);
 130
 131 #ifdef CONFIG_GACT_PROB
 132         {
 133         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 134
 135         if (ptype)
 136                 action = gact_rand[ptype](gact);
 137         }
 138 #endif
 139         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 140         if (action == TC_ACT_SHOT)
 141                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 142
 143         tcf_lastuse_update(&gact->tcf_tm);
 144
 145         return action;
 146 }
 147
 148 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 149 {
 150         unsigned char *b = skb_tail_pointer(skb);
 151         struct tcf_gact *gact = a->priv;
 152         struct tc_gact opt = {
 153                 .index   = gact->tcf_index,
 154                 .refcnt  = gact->tcf_refcnt - ref,
 155                 .bindcnt = gact->tcf_bindcnt - bind,
 156                 .action  = gact->tcf_action,
 157         };
 158         struct tcf_t t;
 159
 160         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 161                 goto nla_put_failure;
 162 #ifdef CONFIG_GACT_PROB
 163         if (gact->tcfg_ptype) {
 164                 struct tc_gact_p p_opt = {
 165                         .paction = gact->tcfg_paction,
 166                         .pval    = gact->tcfg_pval,
 167                         .ptype   = gact->tcfg_ptype,
 168                 };
 169
 170                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 171                         goto nla_put_failure;
 172         }
 173 #endif
 174         t.install = jiffies_to_clock_t(jiffies - gact->tcf_tm.install);
 175         t.lastuse = jiffies_to_clock_t(jiffies - gact->tcf_tm.lastuse);
 176         t.expires = jiffies_to_clock_t(gact->tcf_tm.expires);
 177         if (nla_put(skb, TCA_GACT_TM, sizeof(t), &t))
 178                 goto nla_put_failure;
 179         return skb->len;
 180
 181 nla_put_failure:
 182         nlmsg_trim(skb, b);
 183         return -1;
 184 }
 185
 186 static struct tc_action_ops act_gact_ops = {
 187         .kind           =       "gact",
 188         .type           =       TCA_ACT_GACT,
 189         .owner          =       THIS_MODULE,
 190         .act            =       tcf_gact,
 191         .dump           =       tcf_gact_dump,
 192         .init           =       tcf_gact_init,
 193 };
 194
 195 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 196 MODULE_DESCRIPTION("Generic Classifier actions");
 197 MODULE_LICENSE("GPL");
 198
 199 static int __init gact_init_module(void)
 200 {
 201 #ifdef CONFIG_GACT_PROB
 202         pr_info("GACT probability on\n");
 203 #else
 204         pr_info("GACT probability NOT on\n");
 205 #endif
 206         return tcf_register_action(&act_gact_ops, GACT_TAB_MASK);
 207 }
 208
 209 static void __exit gact_cleanup_module(void)
 210 {
 211         tcf_unregister_action(&act_gact_ops);
 212 }
 213
 214 module_init(gact_init_module);
 215 module_exit(gact_cleanup_module);