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