net/sched/act_simple.c

   1 /*
   2  * net/sched/simp.c     Simple example of an action
   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  * Authors:     Jamal Hadi Salim (2005-8)
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/rtnetlink.h>
  19 #include <net/netlink.h>
  20 #include <net/pkt_sched.h>
  21
  22 #define TCA_ACT_SIMP 22
  23
  24 #include <linux/tc_act/tc_defact.h>
  25 #include <net/tc_act/tc_defact.h>
  26
  27 #define SIMP_TAB_MASK     7
  28 static struct tcf_hashinfo simp_hash_info;
  29
  30 #define SIMP_MAX_DATA   32
  31 static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  32                     struct tcf_result *res)
  33 {
  34         struct tcf_defact *d = a->priv;
  35
  36         spin_lock(&d->tcf_lock);
  37         d->tcf_tm.lastuse = jiffies;
  38         bstats_update(&d->tcf_bstats, skb);
  39
  40         /* print policy string followed by _ then packet count
  41          * Example if this was the 3rd packet and the string was "hello"
  42          * then it would look like "hello_3" (without quotes)
  43          */
  44         pr_info("simple: %s_%d\n",
  45                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  46         spin_unlock(&d->tcf_lock);
  47         return d->tcf_action;
  48 }
  49
  50 static int tcf_simp_release(struct tcf_defact *d, int bind)
  51 {
  52         int ret = 0;
  53         if (d) {
  54                 if (bind)
  55                         d->tcf_bindcnt--;
  56                 d->tcf_refcnt--;
  57                 if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  58                         kfree(d->tcfd_defdata);
  59                         tcf_hash_destroy(&d->common, &simp_hash_info);
  60                         ret = 1;
  61                 }
  62         }
  63         return ret;
  64 }
  65
  66 static int alloc_defdata(struct tcf_defact *d, char *defdata)
  67 {
  68         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  69         if (unlikely(!d->tcfd_defdata))
  70                 return -ENOMEM;
  71         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  72         return 0;
  73 }
  74
  75 static void reset_policy(struct tcf_defact *d, char *defdata,
  76                          struct tc_defact *p)
  77 {
  78         spin_lock_bh(&d->tcf_lock);
  79         d->tcf_action = p->action;
  80         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  81         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  82         spin_unlock_bh(&d->tcf_lock);
  83 }
  84
  85 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  86         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  87         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  88 };
  89
  90 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  91                          struct nlattr *est, struct tc_action *a,
  92                          int ovr, int bind)
  93 {
  94         struct nlattr *tb[TCA_DEF_MAX + 1];
  95         struct tc_defact *parm;
  96         struct tcf_defact *d;
  97         struct tcf_common *pc;
  98         char *defdata;
  99         int ret = 0, err;
 100
 101         if (nla == NULL)
 102                 return -EINVAL;
 103
 104         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
 105         if (err < 0)
 106                 return err;
 107
 108         if (tb[TCA_DEF_PARMS] == NULL)
 109                 return -EINVAL;
 110
 111         if (tb[TCA_DEF_DATA] == NULL)
 112                 return -EINVAL;
 113
 114         parm = nla_data(tb[TCA_DEF_PARMS]);
 115         defdata = nla_data(tb[TCA_DEF_DATA]);
 116
 117         pc = tcf_hash_check(parm->index, a, bind);
 118         if (!pc) {
 119                 pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind);
 120                 if (IS_ERR(pc))
 121                         return PTR_ERR(pc);
 122
 123                 d = to_defact(pc);
 124                 ret = alloc_defdata(d, defdata);
 125                 if (ret < 0) {
 126                         if (est)
 127                                 gen_kill_estimator(&pc->tcfc_bstats,
 128                                                    &pc->tcfc_rate_est);
 129                         kfree_rcu(pc, tcfc_rcu);
 130                         return ret;
 131                 }
 132                 d->tcf_action = parm->action;
 133                 ret = ACT_P_CREATED;
 134         } else {
 135                 d = to_defact(pc);
 136
 137                 if (bind)
 138                         return 0;
 139                 tcf_simp_release(d, bind);
 140                 if (!ovr)
 141                         return -EEXIST;
 142
 143                 reset_policy(d, defdata, parm);
 144         }
 145
 146         if (ret == ACT_P_CREATED)
 147                 tcf_hash_insert(pc, a->ops->hinfo);
 148         return ret;
 149 }
 150
 151 static int tcf_simp_cleanup(struct tc_action *a, int bind)
 152 {
 153         struct tcf_defact *d = a->priv;
 154
 155         if (d)
 156                 return tcf_simp_release(d, bind);
 157         return 0;
 158 }
 159
 160 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 161                          int bind, int ref)
 162 {
 163         unsigned char *b = skb_tail_pointer(skb);
 164         struct tcf_defact *d = a->priv;
 165         struct tc_defact opt = {
 166                 .index   = d->tcf_index,
 167                 .refcnt  = d->tcf_refcnt - ref,
 168                 .bindcnt = d->tcf_bindcnt - bind,
 169                 .action  = d->tcf_action,
 170         };
 171         struct tcf_t t;
 172
 173         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 174             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 175                 goto nla_put_failure;
 176         t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
 177         t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
 178         t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
 179         if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
 180                 goto nla_put_failure;
 181         return skb->len;
 182
 183 nla_put_failure:
 184         nlmsg_trim(skb, b);
 185         return -1;
 186 }
 187
 188 static struct tc_action_ops act_simp_ops = {
 189         .kind           =       "simple",
 190         .hinfo          =       &simp_hash_info,
 191         .type           =       TCA_ACT_SIMP,
 192         .owner          =       THIS_MODULE,
 193         .act            =       tcf_simp,
 194         .dump           =       tcf_simp_dump,
 195         .cleanup        =       tcf_simp_cleanup,
 196         .init           =       tcf_simp_init,
 197 };
 198
 199 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 200 MODULE_DESCRIPTION("Simple example action");
 201 MODULE_LICENSE("GPL");
 202
 203 static int __init simp_init_module(void)
 204 {
 205         int err, ret;
 206         err = tcf_hashinfo_init(&simp_hash_info, SIMP_TAB_MASK);
 207         if (err)
 208                 return err;
 209
 210         ret = tcf_register_action(&act_simp_ops);
 211         if (!ret)
 212                 pr_info("Simple TC action Loaded\n");
 213         else
 214                 tcf_hashinfo_destroy(&simp_hash_info);
 215
 216         return ret;
 217 }
 218
 219 static void __exit simp_cleanup_module(void)
 220 {
 221         tcf_hashinfo_destroy(&simp_hash_info);
 222         tcf_unregister_action(&act_simp_ops);
 223 }
 224
 225 module_init(simp_init_module);
 226 module_exit(simp_cleanup_module);